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45 Commits

Author SHA1 Message Date
nobody
c8bd5fe1d8 This commit was manufactured by cvs2svn to create branch
'compiler_supported_error_messages'.

[SVN r13249]
2002-03-22 12:16:42 +00:00
William E. Kempf
2775a2a945 Updated <runtime-link> info in Jamfile
[SVN r13198]
2002-03-14 23:29:18 +00:00
William E. Kempf
c43c1febba Fixed bug in example in mutex.html
[SVN r13197]
2002-03-14 23:24:16 +00:00
William E. Kempf
ceb6471d57 Updated thread.html for new documentation style.
[SVN r13196]
2002-03-14 23:23:48 +00:00
William E. Kempf
b99cc044f3 Updated Jamfile
[SVN r13095]
2002-03-05 16:27:46 +00:00
Rene Rivera
d91429dcec Moved the <runtime-link> to the build request.
[SVN r13018]
2002-03-02 18:41:22 +00:00
William E. Kempf
b1d1f7d8f1 Jamfile modifications
[SVN r13001]
2002-03-01 23:10:11 +00:00
Dave Abrahams
86b608cf41 Updates to work on Linux
[SVN r12981]
2002-02-28 12:35:05 +00:00
Dave Abrahams
f263f75751 Killed bogus runtime-link specification
[SVN r12946]
2002-02-27 02:11:12 +00:00
William E. Kempf
24bec05b86 Added .cvsignore and updated Jam stuff
[SVN r12944]
2002-02-26 21:02:13 +00:00
William E. Kempf
ce1a5e9359 fixed missing } bug
[SVN r12903]
2002-02-22 18:32:08 +00:00
William E. Kempf
311525bc06 replaced <dll>thread_mon with $(THREADMON_DLL)
[SVN r12902]
2002-02-22 18:31:20 +00:00
William E. Kempf
ecdfd96529 fixed typename warnings
[SVN r12901]
2002-02-22 18:30:34 +00:00
William E. Kempf
5aab32bc1a More Jamfile changes.
[SVN r12857]
2002-02-18 23:04:25 +00:00
William E. Kempf
e152a1c6f2 Updated Jamfiles for new Boost.Build system
[SVN r12856]
2002-02-18 23:02:38 +00:00
Rene Rivera
e84fde78ec Updated the basic Jamfiles for the new Boost.Build changes.
[SVN r12798]
2002-02-14 04:08:20 +00:00
William E. Kempf
6ec4652bcf Updated thread documentation to use new templates.
[SVN r12785]
2002-02-11 23:13:04 +00:00
William E. Kempf
a5239c820b Fixed tabs in files
[SVN r12622]
2002-02-01 17:31:46 +00:00
William E. Kempf
41b001b22c Removed warnings reported by gcc.
[SVN r12492]
2002-01-24 19:17:36 +00:00
William E. Kempf
34e903b8b0 Fixed bug in example.
[SVN r12489]
2002-01-24 19:13:19 +00:00
Mac Murrett
2b67e953fd Changed prefix file to debug_prefix.hpp
[SVN r12487]
2002-01-24 17:33:03 +00:00
Mac Murrett
aa0d3adf1d *** empty log message ***
[SVN r12486]
2002-01-24 17:26:13 +00:00
Mac Murrett
a1f57a8a80 *** empty log message ***
[SVN r12485]
2002-01-24 17:19:44 +00:00
William E. Kempf
6bc82a8580 Added Mac Carbon implementation to Boost.Threads.
[SVN r12480]
2002-01-24 16:32:23 +00:00
William E. Kempf
c4c2e5d3a2 Fixed bug in notify_one that caused deadlock.
[SVN r12178]
2001-12-31 17:18:46 +00:00
Dave Abrahams
dd7d4b2173 Metrowerks needs BOOST_NO_STD_LOCALE in config to be able to compile regex
regex test Jamfile updates so that some tests will actually run
warning suppression for condition.cpp

unit-test rule now accepts input files
updated metrowerks and borland to properly set up path for running tests

----------------------------------------------------------------------
Modified Files:
	boost/config/compiler/metrowerks.hpp
	libs/python/src/gen_function.py libs/regex/test/Jamfile
 Tag: thread-initial
	libs/thread/src/condition.cpp
 No tag
	tools/build/boost-base.jam tools/build/borland-tools.jam
	tools/build/metrowerks-tools.jam
----------------------------------------------------------------------


[SVN r11853]
2001-12-02 17:43:45 +00:00
Beman Dawes
2719c4d545 Try to get the date stamps in sync
[SVN r11618]
2001-11-07 00:37:59 +00:00
Beman Dawes
33c1e36b54 Add "Why has semaphore disappeared" FAQ
[SVN r11586]
2001-11-05 15:42:10 +00:00
William E. Kempf
e7e46e185e Fixed bug found compiling with gcc.
[SVN r11584]
2001-11-05 15:13:57 +00:00
William E. Kempf
9200d48873 Added lock_ops<> detail concept.
[SVN r11540]
2001-11-02 23:34:50 +00:00
William E. Kempf
831d054d24 Added exceptions.cpp.
[SVN r11502]
2001-11-01 16:19:44 +00:00
William E. Kempf
f3af804ddb Removed semaphores. Fixed some reported bugs. Switched to CRITICAL_SECTION implementations.
[SVN r11501]
2001-11-01 16:18:57 +00:00
John Maddock
1f35149ef0 Added code to normalise timespec structures.
[SVN r11500]
2001-11-01 12:56:57 +00:00
William E. Kempf
554a18842f Switched to void* for HANDLE types. Changed boost::once_init to the macro BOOST_ONCE_INIT.
[SVN r11475]
2001-10-30 22:12:37 +00:00
William E. Kempf
869243b6d1 Updated Jamfiles for PTW32, removed _atomic.cpp and added Win32 conditional compilation blocks for threadmon files.
[SVN r11468]
2001-10-29 22:20:50 +00:00
William E. Kempf
c0da02326a Fixed reported documentation bugs.
[SVN r11462]
2001-10-29 16:58:17 +00:00
William E. Kempf
9b5f666fc5 Removed tabs and trailing white space.
[SVN r11403]
2001-10-18 19:56:32 +00:00
William E. Kempf
1ce93426a4 Fixed Jamfile.
[SVN r11396]
2001-10-16 22:10:45 +00:00
William E. Kempf
6dacf3478b Fixed sprintf bugs in once.cpp.
[SVN r11395]
2001-10-16 19:32:20 +00:00
William E. Kempf
dff91699c3 Fixed more warnings and errors found when compiling with gcc.
[SVN r11388]
2001-10-15 21:28:11 +00:00
William E. Kempf
9f83e8c1fc Modified Jamfile to allow for building using pthreads-win32 (code is commented out).
[SVN r11387]
2001-10-15 18:34:01 +00:00
William E. Kempf
7b07cb0759 Fixed errors and warnings for gcc. Still some outstanding issues for gcc on Win32.
[SVN r11386]
2001-10-15 18:32:21 +00:00
William E. Kempf
c2e7091632 Fixed reported warnings. Fixed once bug with void* and function pointer conversion.
[SVN r11385]
2001-10-15 00:48:51 +00:00
Beman Dawes
1ab320042e Minor typo fix and wording improvements
[SVN r11365]
2001-10-08 20:20:07 +00:00
William E. Kempf
b0cd307eaf Ran "tidy" against documentation.
[SVN r11329]
2001-10-02 16:13:25 +00:00
105 changed files with 8110 additions and 4285 deletions

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# in all copies. This software is provided "as is" without express or implied
# warranty, and with no claim as to its suitability for any purpose.
#
# Boost.Threads build and test Jamfile
# Boost.Threads build Jamfile
#
# Declares the following targets:
# 1. libboost_thread, a static link library.
# 1a. On Win32, a dynamic link library libboost_threadmon,
# which must be used in conjunction with libboost_thread.
# 1a. On Win32 (when PTW32 is not defined), a dynamic link library
# boost_threadmon, which must be used in conjunction with
# libboost_thread. Note that this DLL *must* be used through static
# linking to the import library. Dynamic loading will cause undefined
# behavior.
# Additional configuration variables used:
# 1. PTW32 may be used on Win32 platforms to specify that the pthreads-win32
# library should be used instead of "native" threads. This feature is
# mostly used for testing and it's generally recommended you use the
# native threading libraries instead. PTW32 should be set to be a list
# of two strings, the first specifying the installation path of the
# pthreads-win32 library and the second specifying which library
# variant to link against (see the pthreads-win32 documentation).
# Example: jam -sPTW32="c:\pthreads-win32 pthreadVCE.lib"
# declare the location of this subproject relative to the root
# Declare the location of this subproject relative to the root.
subproject libs/thread/build ;
# Include threads.jam for Boost.Threads global build information.
# This greatly simplifies the Jam code needed to configure the build
# for the various Win32 build types.
SEARCH on <module@>threads.jam = $(BOOST_ROOT)/libs/thread/build ;
include <module@>threads.jam ;
#######################
# Conditionally declare the Boost.Threads dynamic link library boost_threadmon.
#
# Declare the Boost.Threads static link library.
#
# For Win32 we need to build a special DLL, libboost_threadmon, to handle
# TSS destruction.
if $(NT)
if $(NT) && ! $(PTW32)
{
dll libboost_threadmon : ../src/threadmon.cpp
# requirements
: <threading>multi
: debug release ;
dll boost_threadmon
: ../src/threadmon.cpp
: <include>$(BOOST_ROOT)
<threading>multi
: debug release <runtime-link>static/dynamic
;
}
# Base names of the source files for libboost_thread
CPP_SOURCES =
condition mutex recursive_mutex semaphore thread tss xtime once ;
#######################
# Declare the Boost.Threads static link library libboost_thread.
lib libboost_thread : ../src/$(CPP_SOURCES).cpp
# requirements
# Base names of the source files for libboost_thread.
CPP_SOURCES =
condition mutex recursive_mutex thread tss xtime once exceptions ;
lib boost_thread
: ../src/$(CPP_SOURCES).cpp
: <include>$(BOOST_ROOT)
<threading>multi
: debug release ;
<threading>multi
$(pthreads-win32)
: debug release <runtime-link>static/dynamic
;
#######################
# Stage the generated targets.
stage bin-stage
: <lib>boost_thread $(threadmon)
: <tag><runtime-link-static>"s"
<tag><debug>"d"
: debug release <runtime-link>static/dynamic
;

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# Do some OS-specific setup
threadmon = ;
pthreads-win32 = ;
if $(NT)
{
if $(PTW32)
{
local install-path = $(PTW32[1]) ;
local lib = $(PTW32[2]) ;
pthreads-win32 =
<define>BOOST_HAS_PTHREADS
<define>PtW32NoCatchWarn
<include>$(install-path)/pre-built/include
<library-file>$(install-path)/pre-built/lib/$(lib)
;
}
else
{
threadmon = <dll>../build/boost_threadmon ;
}
}

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<html>
<head>
<meta http-equiv="Content-Type" content=
"text/html; charset=windows-1252">
<meta name="GENERATOR" content="Microsoft FrontPage 4.0">
<meta name="ProgId" content="FrontPage.Editor.Document">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=windows-1252">
<meta name="GENERATOR" content="Microsoft FrontPage 4.0">
<meta name="ProgId" content="FrontPage.Editor.Document">
<title>Boost.Threads Acknowledgements</title>
</head>
<title>Boost.Threads Acknowledgements</title>
</head>
<body bgcolor="#FFFFFF" text="#000000">
<body bgcolor="#FFFFFF" text="#000000">
<table summary="header" border="0" cellpadding="7" cellspacing="0"
width="100%">
<tr>
<td valign="top" width="300">
<h3><img src="../../../c++boost.gif" alt="C++ Boost" width=
"277" height="86"></h3>
</td>
<table border="0" cellpadding="7" cellspacing="0" width="100%">
<tr>
<td valign="top" width="300">
<h3><img src="../../../c++boost.gif" alt="C++ Boost" width="277" height="86"></h3>
</td>
<td valign="top">
<h1 align="center">Boost.Threads</h1>
<h2 align="center">Acknowledgements</h2>
</td>
</tr>
</table>
<td valign="top">
<h1 align="center">Boost.Threads</h1>
<h2>Acknowledgments</h2>
<h2 align="center">Acknowledgements</h2>
</td>
</tr>
</table>
<p><a href="../../../people/william_kempf.htm">William E. Kempf</a> was the
architect, designer, and implementor of <b>Boost.Threads</b>.</p>
<h2>Acknowledgments</h2>
<p>Important contributions were also made by Jeremy Siek (lots of input on
the design and on the implementation), Alexander Terekhov (lots of input on
the Win32 implementation, especially in regards to boost::condition, as well
as a lot of explanation of POSIX behavior), Greg Colvin (lots of input on the
design), and Paul Mclachlan, Thomas Matelich and Iain Hanson (for help in
trying to get the build to work on other platforms).</p>
<p><a href="../../../people/william_kempf.htm">William E. Kempf</a> was
the architect, designer, and implementor of <b>Boost.Threads</b>.</p>
<p>The documentation was written by William E. Kempf. Beman Dawes provided
additional documentation material and editing.</p>
<p>Mac OS Carbon implementation written by
<a href="../../../people/mac_murrett.htm">Mac Murrett</a>.</p>
<p>Discussions on the boost.org mailing list were essential in the development
of <b>Boost.Threads</b>. As of August 1, 2001, participants included Alan Griffiths,
Albrecht Fritzsche, Aleksey Gurtovoy, Alexander Terekhov, Andrew Green, Andy Sawyer,
Asger Alstrup Nielsen, Beman Dawes, Bill Klein, Bill Rutiser, Bill Wade, Branko
Èibej, Brent Verner, Craig Henderson, Csaba Szepesvari, Dale Peakall, Damian
Dixon, Dan Nuffer, Darryl Green, Daryle Walker, David Abrahams, David Allan
Finch, Dejan Jelovic, Dietmar Kuehl, Doug Gregor, Douglas Gregor, Duncan Harris,
Ed Brey, Eric Swanson, Eugene Karpachov, Fabrice Truillot, Frank
Gerlach, Gary Powell, Gernot Neppert, Geurt Vos, Ghazi Ramadan, Greg Colvin,
Gregory Seidman, HYS, Iain Hanson, Ian Bruntlett, J Panzer, Jeff Garland, Jeff
Paquette, Jens Maurer, Jeremy Siek, Jesse Jones, Joe Gottman, John (EBo) David,
John Bandela, John Maddock, John Max Skaller, John Panzer, Jon Jagger , Karl
Nelson, Kevlin Henney, KG Chandrasekhar, Levente Farkas, Lie-Quan Lee, Lois
Goldthwaite, Luis Pedro Coelho, Marc Girod, Mark A. Borgerding, Mark Rodgers,
Marshall Clow, Matthew Austern, Matthew Hurd, Michael D. Crawford, Michael H.
Cox , Mike Haller, Miki Jovanovic, Nathan Myers, Paul Moore, Pavel Cisler, Peter
Dimov, Petr Kocmid, Philip Nash, Rainer Deyke, Reid Sweatman, Ross Smith, Scott
McCaskill, Shalom Reich , Steve Cleary, Steven Kirk, Thomas Holenstein, Thomas
Matelich, Trevor Perrin, Valentin Bonnard, Vesa Karvonen, Wayne Miller, and
William Kempf.</p>
<p>Important contributions were also made by Jeremy Siek (lots of input
on the design and on the implementation), Alexander Terekhov (lots of
input on the Win32 implementation, especially in regards to
boost::condition, as well as a lot of explanation of POSIX behavior),
Greg Colvin (lots of input on the design), and Paul Mclachlan, Thomas
Matelich and Iain Hanson (for help in trying to get the build to work
on other platforms).</p>
<p>Apologies for anyone inadvertently missed.</p>
<p>The documentation was written by William E. Kempf. Beman Dawes
provided additional documentation material and editing.</p>
<hr>
<p>Discussions on the boost.org mailing list were essential in the
development of <b>Boost.Threads</b>. As of August 1, 2001, participants
included Alan Griffiths, Albrecht Fritzsche, Aleksey Gurtovoy,
Alexander Terekhov, Andrew Green, Andy Sawyer, Asger Alstrup Nielsen,
Beman Dawes, Bill Klein, Bill Rutiser, Bill Wade, Branko &Egrave;ibej,
Brent Verner, Craig Henderson, Csaba Szepesvari, Dale Peakall, Damian
Dixon, Dan Nuffer, Darryl Green, Daryle Walker, David Abrahams, David
Allan Finch, Dejan Jelovic, Dietmar Kuehl, Doug Gregor, Douglas Gregor,
Duncan Harris, Ed Brey, Eric Swanson, Eugene Karpachov, Fabrice
Truillot, Frank Gerlach, Gary Powell, Gernot Neppert, Geurt Vos, Ghazi
Ramadan, Greg Colvin, Gregory Seidman, HYS, Iain Hanson, Ian Bruntlett,
J Panzer, Jeff Garland, Jeff Paquette, Jens Maurer, Jeremy Siek, Jesse
Jones, Joe Gottman, John (EBo) David, John Bandela, John Maddock, John
Max Skaller, John Panzer, Jon Jagger , Karl Nelson, Kevlin Henney, KG
Chandrasekhar, Levente Farkas, Lie-Quan Lee, Lois Goldthwaite, Luis
Pedro Coelho, Marc Girod, Mark A. Borgerding, Mark Rodgers, Marshall
Clow, Matthew Austern, Matthew Hurd, Michael D. Crawford, Michael H.
Cox , Mike Haller, Miki Jovanovic, Nathan Myers, Paul Moore, Pavel
Cisler, Peter Dimov, Petr Kocmid, Philip Nash, Rainer Deyke, Reid
Sweatman, Ross Smith, Scott McCaskill, Shalom Reich , Steve Cleary,
Steven Kirk, Thomas Holenstein, Thomas Matelich, Trevor Perrin,
Valentin Bonnard, Vesa Karvonen, Wayne Miller, and William Kempf.</p>
<p>Revised <!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->01 October, 2001<!--webbot bot="Timestamp" endspan i-checksum="38291" -->
</p>
<p>Apologies for anyone inadvertently missed.</p>
<hr>
<p>©<i> Copyright <a href="mailto:williamkempf@hotmail.com">William E. Kempf</a>
2001</i></p>
</body>
<p>Revised
<!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->05 November, 2001<!--webbot bot="Timestamp" endspan i-checksum="39359" --></p>
<p>&copy; <i>Copyright <a href="mailto:williamkempf@hotmail.com">
William E. Kempf</a> 2001</i></p>
</body>
</html>

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@@ -1,145 +1,222 @@
<html>
<head>
<meta http-equiv="Content-Type" content=
"text/html; charset=windows-1252">
<meta name="GENERATOR" content="Microsoft FrontPage 4.0">
<meta name="ProgId" content="FrontPage.Editor.Document">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=windows-1252">
<meta name="GENERATOR" content="Microsoft FrontPage 4.0">
<meta name="ProgId" content="FrontPage.Editor.Document">
<title>Boost.Threads Bibliography</title>
</head>
<title>Boost.Threads Bibliography</title>
</head>
<body bgcolor="#FFFFFF" text="#000000">
<body bgcolor="#FFFFFF" text="#000000">
<table summary="header" border="0" cellpadding="7" cellspacing="0"
width="100%">
<tr>
<td valign="top" width="300">
<h3><img src="../../../c++boost.gif" alt="C++ Boost" width=
"277" height="86"></h3>
</td>
<table border="0" cellpadding="7" cellspacing="0" width="100%">
<tr>
<td valign="top" width="300">
<h3><img src="../../../c++boost.gif" alt="C++ Boost" width="277" height="86"></h3>
</td>
<td valign="top">
<h1 align="center">Boost.Threads</h1>
<h2 align="center">Bibliography</h2>
</td>
</tr>
</table>
<h2>Bibliography</h2>
<table border="0" cellpadding="5" width="777">
<tr>
<td width="102" valign="top" align="left"><b>[<a name="Andrews-83">Andrews
83</a>]</b></td>
<td width="645">
Gregory R. Andrews, Fred B. Schneider, <cite>Concepts and Notations for Concurrent
Programming</cite>, ACM Computing Surveys, Vol. 15, No. 1, March, 1983. <a href="http://www.acm.org/pubs/citations/journals/surveys/1983-15-1/p3-andrews/">http://www.acm.org/pubs/citations/journals/surveys/1983-15-1/p3-andrews/</a>
<p>Good general background reading.&nbsp; Includes descriptions of Path
Expressions, Message Passing, and Remote Procedure Call in addition to the
basics.&nbsp;
</td>
</tr>
<tr>
<td width="102" valign="top" align="left"><b>[<a name="Boost">Boost</a>]</b></td>
<td width="645">
The <cite> Boost</cite> world-wide web site.&nbsp; <a href="http://www.boost.org">http://www.boost.org</a>
<p>Boost.Threads is one of many Boost libraries.&nbsp; The Boost web site
includes a great deal of documentation and general information which applies to
all Boost libraries. Current copies of the libraries including documentation and
test programs may be downloaded from the web site.
</td>
</tr>
<tr>
<td width="102" valign="top" align="left"><b>[<a name="Brinch-Hansen-73">Brinch
Hansen 73</a>]</b></td>
<td width="645">
Per Brinch Hansen, <cite>Concurrent Programming Concepts</cite>, ACM Computing
Surveys, Vol. 5, No. 4, December, 1973. <a href="http://www.acm.org/pubs/articles/journals/surveys/1973-5-4/p223-hansen/p223-hansen.pdf">http://www.acm.org/pubs/articles/journals/surveys/1973-5-4/p223-hansen/</a>
<p>&quot;This paper describes the evolution of language features for
multiprogramming from event queues and semaphores to critical regions and
monitors.&quot; Includes analysis of&nbsp; why <i>events</i> are considered
error-prone. Also noteworthy because of an introductory quotation from
Christopher Alexander; Brinch Hansen was years ahead of others in recognizing
pattern concepts applied to software too.
</td>
</tr>
<tr>
<td width="102" valign="top" align="left"><b>]<a name="Butenhof-97">Butenhof
97</a>]</b></td>
<td width="645">
<p> David R. Butenhof, <cite>Programming with
POSIX Threads</cite>, Addison-Wesley 1997, ISBN 0-201-63392-2&nbsp; <a href="http://cseng.aw.com/book/0,3828,0201633922,00.html">http://cseng.aw.com/book/0,3828,0201633922,00.html</a></p>
<p>This is a very readable explanation of threads and how to use them.&nbsp; Many
of the insights given apply to all multi-threaded programming, not just POSIX
Threads.</p>
</td>
</tr>
<tr>
<td width="102" valign="top" align="left"><b>[<a name="Hoare-74">Hoare 74</a>]</b></td>
<td width="645">
<p>C.A.R Hoare, <cite> Monitors: An Operating System Structuring Concept</cite>,
Communications of the ACM, Vol. 17, No. 10. October
1974, pp. 549-557&nbsp; <a href="http://www.acm.org/classics/feb96/">http://www.acm.org/classics/feb96/ </a></p>
<p>Hoare and Brinch Hansen's work on Monitors is the basis for reliable
multi-threading patterns. This is one of the most often referenced papers in
all of computer science, and with good reason.</p>
</td>
</tr>
<tr>
<td width="102" valign="top" align="left"><b>[<a name="ISO-98">ISO 98</a>]</b></td>
<td width="645">
<p>ISO/IEC 14882:1998(E) <cite> Programming Language C++</cite>&nbsp; <a href="http://www.ansi.org">http://www.ansi.org</a></p>
<p>This is the official C++ Standards
document. Available from the ANSI (American
National Standards Institute) Electronic Standards Store.</p>
</td>
</tr>
<tr>
<td width="102" valign="top" align="left"><b>[<a name="McDowell-89">McDowell
89</a>]</b></td>
<td width="645">
Charles E McDowell, David P. Helmbold, <cite>Debugging Concurrent Programs</cite>,
ACM Computing Surveys, Vol. 21, No. 2, December, 1989. <a href="http://www.acm.org/pubs/citations/journals/surveys/1989-21-4/p593-mcdowell/">http://www.acm.org/pubs/citations/journals/surveys/1989-21-4/p593-mcdowell/</a>
<p>Identifies many of the unique failure modes and debugging difficulties
associated with concurrent programs.
</td>
</tr>
<tr>
<td width="102" valign="top" align="left"> <b>[<a name="Schmidt">Schmidt</a>]&nbsp;</b></td>
<td width="645">
<p> Douglas C. Schmidt and Irfan Pyarali, <cite>Strategies for
Implementing POSIX Condition Variables on Win32</cite>,&nbsp; Department of Computer Science, Washington University, St. Louis, Missouri.&nbsp;
<a href="http://www.cs.wustl.edu/~schmidt/win32-cv-1.html">http://www.cs.wustl.edu/~schmidt/win32-cv-1.html</a></p>
<p>Rationale for understanding Boost.Threads condition variables. Note that Alexander Terekhov found some bugs in
the implementation given in this article, so pthreads-win32 and Boost.Threads
are even more complicated yet.</p>
</td>
</tr>
<tr>
<td width="102" valign="top" align="left"> <b>[<a name="Schmidt-00">Schmidt
00</a>]&nbsp;</b></td>
<td width="645">
<p> Douglas C. Schmidt, Michael Stal, Hans Rohnert and Frank Buschmann, <cite>Pattern-Oriented Software Architecture Volume 2 - Patterns for
Concurrent and Networked Objects</cite>,&nbsp; Wiley 2000, ISBN 0-471-60695-2&nbsp; <a href="http://www.wiley.com/Corporate/Website/Objects/Products/0,9049,104671,00.html">http://www.wiley.com/Corporate/Website/Objects/Products/0,9049,104671,00.html</a></p>
<p>This is a very good explanation of how to apply several patterns useful for concurrent programming.
Among the patterns documented is the Monitor Pattern mentioned frequently in the <b>Boost.Threads</b>
documentation.</p>
</td>
</tr>
<tr>
<td width="102" valign="top" align="left"> <b>[<a name="Stroustrup-00">Stroustrup
00</a>]</b></td>
<td width="645">
Bjarne Stroustrup, <cite> The C++ Programming Language</cite>, Special Edition, Addison-Wesley
2000, ISBN 0-201-70073-5 <a href="http://cseng.aw.com/book/0,3828,0201700735,00.html">http://cseng.aw.com/book/0,3828,0201700735,00.html</a>
<p>The first book a C++ programmer should own.&nbsp; Note that the 3rd edition
(and subsequent editions like the Special Edition) has been rewritten to cover
the ISO standard language and library.
</td>
</tr>
</table>
<p>Note: The URL's above are provided in plain text form so that they will be visible
on printed copies of this document.</p>
<hr>
<p>Revised <!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %b %Y" startspan -->01 Oct 2001<!--webbot bot="Timestamp" endspan i-checksum="14990" -->
</p>
<td valign="top">
<h1 align="center">Boost.Threads</h1>
<p>© Copyright Beman Dawes, 2001</p>
<h2 align="center">Bibliography</h2>
</td>
</tr>
</table>
</body>
<h2>Bibliography</h2>
<table summary="Bibliography" border="0" cellpadding="5" width="777">
<tr>
<td width="102" valign="top" align="left"><b>[<a name=
"Andrews-83">Andrews 83</a>]</b></td>
<td width="645">
Gregory R. Andrews, Fred B. Schneider, <cite>Concepts and
Notations for Concurrent Programming</cite>, ACM Computing
Surveys, Vol. 15, No. 1, March, 1983. <a href=
"http://www.acm.org/pubs/citations/journals/surveys/1983-15-1/p3-andrews/">
http://www.acm.org/pubs/citations/journals/surveys/1983-15-1/p3-andrews/</a>
<p>Good general background reading. Includes descriptions
of Path Expressions, Message Passing, and Remote Procedure
Call in addition to the basics.</p>
</td>
</tr>
<tr>
<td width="102" valign="top" align="left"><b>[<a name=
"Boost">Boost</a>]</b></td>
<td width="645">
The <cite>Boost</cite> world-wide web site. <a href=
"http://www.boost.org">http://www.boost.org</a>
<p>Boost.Threads is one of many Boost libraries. The Boost
web site includes a great deal of documentation and general
information which applies to all Boost libraries. Current
copies of the libraries including documentation and test
programs may be downloaded from the web site.</p>
</td>
</tr>
<tr>
<td width="102" valign="top" align="left"><b>[<a name=
"Brinch-Hansen-73">Brinch Hansen 73</a>]</b></td>
<td width="645">
Per Brinch Hansen, <cite>Concurrent Programming
Concepts</cite>, ACM Computing Surveys, Vol. 5, No. 4,
December, 1973. <a href=
"http://www.acm.org/pubs/articles/journals/surveys/1973-5-4/p223-hansen/p223-hansen.pdf">
http://www.acm.org/pubs/articles/journals/surveys/1973-5-4/p223-hansen/</a>
<p>&quot;This paper describes the evolution of language
features for multiprogramming from event queues and
semaphores to critical regions and monitors.&quot; Includes
analysis of why <i>events</i> are considered error-prone.
Also noteworthy because of an introductory quotation from
Christopher Alexander; Brinch Hansen was years ahead of
others in recognizing pattern concepts applied to software
too.</p>
</td>
</tr>
<tr>
<td width="102" valign="top" align="left"><b>]<a name=
"Butenhof-97">Butenhof 97</a>]</b></td>
<td width="645">
<p>David R. Butenhof, <cite>Programming with POSIX
Threads</cite>, Addison-Wesley 1997, ISBN 0-201-63392-2 <a
href="http://cseng.aw.com/book/0,3828,0201633922,00.html">
http://cseng.aw.com/book/0,3828,0201633922,00.html</a></p>
<p>This is a very readable explanation of threads and how
to use them. Many of the insights given apply to all
multi-threaded programming, not just POSIX Threads.</p>
</td>
</tr>
<tr>
<td width="102" valign="top" align="left"><b>[<a name=
"Hoare-74">Hoare 74</a>]</b></td>
<td width="645">
<p>C.A.R Hoare, <cite>Monitors: An Operating System
Structuring Concept</cite>, Communications of the ACM, Vol.
17, No. 10. October 1974, pp. 549-557 <a href=
"http://www.acm.org/classics/feb96/">
http://www.acm.org/classics/feb96/</a></p>
<p>Hoare and Brinch Hansen&#39;s work on Monitors is the
basis for reliable multi-threading patterns. This is one of
the most often referenced papers in all of computer
science, and with good reason.</p>
</td>
</tr>
<tr>
<td width="102" valign="top" align="left"><b>[<a name=
"ISO-98">ISO 98</a>]</b></td>
<td width="645">
<p>ISO/IEC 14882:1998(E) <cite>Programming Language
C++</cite> <a href="http://www.ansi.org">
http://www.ansi.org</a></p>
<p>This is the official C++ Standards document. Available
from the ANSI (American National Standards Institute)
Electronic Standards Store.</p>
</td>
</tr>
<tr>
<td width="102" valign="top" align="left"><b>[<a name=
"McDowell-89">McDowell 89</a>]</b></td>
<td width="645">
Charles E McDowell, David P. Helmbold, <cite>Debugging
Concurrent Programs</cite>, ACM Computing Surveys, Vol. 21,
No. 2, December, 1989. <a href=
"http://www.acm.org/pubs/citations/journals/surveys/1989-21-4/p593-mcdowell/">
http://www.acm.org/pubs/citations/journals/surveys/1989-21-4/p593-mcdowell/</a>
<p>Identifies many of the unique failure modes and
debugging difficulties associated with concurrent
programs.</p>
</td>
</tr>
<tr>
<td width="102" valign="top" align="left"><b>[<a name=
"Schmidt">Schmidt</a>]</b> </td>
<td width="645">
<p>Douglas C. Schmidt and Irfan Pyarali, <cite>Strategies
for Implementing POSIX Condition Variables on Win32</cite>,
Department of Computer Science, Washington University, St.
Louis, Missouri. <a href=
"http://www.cs.wustl.edu/~schmidt/win32-cv-1.html">
http://www.cs.wustl.edu/~schmidt/win32-cv-1.html</a></p>
<p>Rationale for understanding Boost.Threads condition
variables. Note that Alexander Terekhov found some bugs in
the implementation given in this article, so pthreads-win32
and Boost.Threads are even more complicated yet.</p>
</td>
</tr>
<tr>
<td width="102" valign="top" align="left"><b>[<a name=
"Schmidt-00">Schmidt 00</a>]</b> </td>
<td width="645">
<p>Douglas C. Schmidt, Michael Stal, Hans Rohnert and Frank
Buschmann, <cite>Pattern-Oriented Software Architecture
Volume 2 - Patterns for Concurrent and Networked
Objects</cite>, Wiley 2000, ISBN 0-471-60695-2 <a href=
"http://www.wiley.com/Corporate/Website/Objects/Products/0,9049,104671,00.html">
http://www.wiley.com/Corporate/Website/Objects/Products/0,9049,104671,00.html</a></p>
<p>This is a very good explanation of how to apply several
patterns useful for concurrent programming. Among the
patterns documented is the Monitor Pattern mentioned
frequently in the <b>Boost.Threads</b> documentation.</p>
</td>
</tr>
<tr>
<td width="102" valign="top" align="left"><b>[<a name=
"Stroustrup-00">Stroustrup 00</a>]</b></td>
<td width="645">
Bjarne Stroustrup, <cite>The C++ Programming
Language</cite>, Special Edition, Addison-Wesley 2000, ISBN
0-201-70073-5 <a href=
"http://cseng.aw.com/book/0,3828,0201700735,00.html">
http://cseng.aw.com/book/0,3828,0201700735,00.html</a>
<p>The first book a C++ programmer should own. Note that
the 3rd edition (and subsequent editions like the Special
Edition) has been rewritten to cover the ISO standard
language and library.</p>
</td>
</tr>
</table>
<p>Note: The URL&#39;s above are provided in plain text form so that
they will be visible on printed copies of this document.</p>
<hr>
<p>Revised
<!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %b %Y" startspan -->05 Nov 2001<!--webbot bot="Timestamp" endspan i-checksum="15246" --></p>
<p>&copy; Copyright Beman Dawes, 2001</p>
</body>
</html>

View File

@@ -1,48 +1,52 @@
<html>
<head>
<meta http-equiv="Content-Type" content=
"text/html; charset=iso-8859-1">
<meta name="keywords" content=
"threads, Boost.Threads, thread library, C++">
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<meta name="keywords" content="threads, Boost.Threads, thread library, C++">
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<title>Boost.Threads, call_once</title>
</head>
<title>Boost.Threads, call_once</title>
</head>
<body bgcolor="#FFFFFF" link="#0000FF" vlink="#800080">
<body bgcolor="#FFFFFF" link="#0000FF" vlink="#800080">
<table summary="header" border="0" cellpadding="7" cellspacing="0"
width="100%">
<tr>
<td valign="top" width="300">
<h3><img src="../../../c++boost.gif" alt="C++ Boost" width=
"277" height="86"></h3>
</td>
<table border="0" cellpadding="7" cellspacing="0" width="100%">
<tr>
<td valign="top" width="300">
<h3><img src="../../../c++boost.gif" alt="C++ Boost" width="277" height="86"></h3>
</td>
<td valign="top">
<h1 align="center">Boost.Threads</h1>
<h2 align="center">call_once</h2>
</td>
</tr>
</table>
<td valign="top">
<h1 align="center">Boost.Threads</h1>
<hr>
<h2 align="center">call_once</h2>
</td>
</tr>
</table>
<hr>
<p><A href="#Introduction">Introduction</A><br>
<A href="#Header">Header</A><br>
<A href="#Synopsis">Synopsis</A><br>
<A href="#Members">Members</A><br>
<A href="#Example">Example</A></p>
<p><a href="#Introduction">Introduction</a><br>
<a href="#Header">Header</a><br>
<a href="#Synopsis">Synopsis</a><br>
<a href="#Members">Members</a><br>
<a href="#Example">Example</a></p>
<h2><a name="Introduction">Introduction</a></h2>
<h2><a name="Introduction">Introduction</a></h2>
<p>The <code>call_once</code> routine and <code>once_flag</code> type can be used to
run a routine exactly once. This can be used to initialize data in a
<a href="definitions.html#Thread-safe">thread-safe</a> manner.</p>
<h2><a name="Header">Header</a></h2>
<p>The <code>call_once</code> routine and <code>once_flag</code> type
can be used to run a routine exactly once. This can be used to
initialize data in a <a href="definitions.html#Thread-safe">
thread-safe</a> manner.</p>
<h2><a name="Header">Header</a></h2>
<pre>
#include <a href="../../../boost/thread/once.hpp">&lt;boost/thread/once.hpp&gt;</a>
#include <a href=
"../../../boost/thread/once.hpp">&lt;boost/thread/once.hpp&gt;</a>
</pre>
<h2><a name="Synopsis">Synopsis</a></h2>
<h2><a name="Synopsis">Synopsis</a></h2>
<pre>
namespace boost {
@@ -53,44 +57,45 @@ void call_once(void (*func)(), once_flag&amp; flag);
} // namespace boost
</pre>
<h2><a name="Reference">Reference</a></h2>
<h2><a name="Reference">Reference</a></h2>
<hr>
<hr>
<h3>once_flag</h3>
<h3>once_flag</h3>
<p>This implementation defined type is used as a flag to insure a routine is called only once.
Instances of this type should be statically initialized to <code>once_init</code>.</p>
<p>This implementation defined type is used as a flag to insure a
routine is called only once. Instances of this type should be
statically initialized to <code>once_init</code>.</p>
<hr>
<hr>
<h3>once_init</h3>
<h3>once_init</h3>
<p>This is a constant value used to initialize <code>once_flag</code> instances
to indicate that the logically associated routine has not been run yet.</p>
<hr>
<h3>call_once</h3>
<p>This is a constant value used to initialize <code>once_flag</code>
instances to indicate that the logically associated routine has not
been run yet.</p>
<hr>
<h3>call_once</h3>
<pre>
void call_once(void (*func)(), once_flag&amp; flag);
</pre>
<p><b>Requires:</b> The function <code>func</code> shall not throw exceptions.</p>
<p><b>Requires:</b> The function <code>func</code> shall not throw
exceptions.</p>
<p><b>Effects:</b> As if (in an atomic fashion)</p>
<p><b>Effects:</b> As if (in an atomic fashion)</p>
<code>&nbsp;&nbsp;&nbsp;if (flag == once_init)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;func();</code>
<code>
&nbsp;&nbsp;&nbsp;if (flag == once_init)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;func();
</code>
<p><b>Postcondition:</b> <code>flag</code> != <code>once_init</code></p>
<hr>
<h2><a name="Example">Example Usage</a></h2>
<p><b>Postcondition:</b> <code>flag</code> != <code>
once_init</code></p>
<hr>
<h2><a name="Example">Example Usage</a></h2>
<pre>
#include <a href="../../../boost/thread/thread.hpp">&lt;boost/thread/thread.hpp&gt;</a>
#include <a href="../../../boost/thread/tss.hpp">&lt;boost/thread/once.hpp&gt;</a>
#include <a href=
"../../../boost/thread/thread.hpp">&lt;boost/thread/thread.hpp&gt;</a>
#include <a href=
"../../../boost/thread/tss.hpp">&lt;boost/thread/once.hpp&gt;</a>
#include &lt;cassert&gt;
int value=0;
@@ -98,7 +103,7 @@ boost::once_flag once = boost::once_init;
void init()
{
++value;
++value;
}
void thread_proc()
@@ -115,14 +120,13 @@ int main(int argc, char* argv[])
assert(value == 1);
}
</pre>
<hr>
<hr>
<p>Revised
<!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->05 November, 2001<!--webbot bot="Timestamp" endspan i-checksum="39359" --></p>
<p>Revised <!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->01 October, 2001<!--webbot bot="Timestamp" endspan i-checksum="38291" -->
</p>
<p><i>© Copyright <a href="mailto:williamkempf@hotmail.com">William E. Kempf</a>
2001 all rights reserved.</i></p>
</body>
<p><i>&copy; Copyright <a href="mailto:williamkempf@hotmail.com">
William E. Kempf</a> 2001 all rights reserved.</i></p>
</body>
</html>

View File

@@ -1,72 +1,80 @@
<html>
<head>
<meta http-equiv="Content-Type" content=
"text/html; charset=iso-8859-1">
<meta name="keywords" content="threads, BTL, thread library, C++">
<link rel="stylesheet" type="text/css" href="styles.css">
<head>
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<meta name="keywords" content="threads, BTL, thread library, C++">
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<title>Boost.Threads, condition</title>
</head>
<title>Boost.Threads, condition</title>
</head>
<body bgcolor="#ffffff" link="#0000ff" vlink="#800080" text="#000000">
<body bgcolor="#ffffff" link="#0000ff" vlink="#800080" text="#000000">
<table summary="header" border="0" cellpadding="7" cellspacing="0"
width="100%">
<tr>
<td valign="top" width="300">
<h3><img height="86" alt="C++ Boost" src=
"../../../c++boost.gif" width="277"></h3>
</td>
<table border="0" cellpadding="7" cellspacing="0" width="100%">
<tr>
<td valign="top" width="300">
<h3><IMG height=86 alt="C++ Boost" src="../../../c++boost.gif" width=277></h3>
</td>
<td valign="top">
<h1 align="center">Boost.Threads</h1>
<h2 align="center">condition</h2>
</td>
</tr>
</table>
<td valign="top">
<h1 align="center">Boost.Threads</h1>
<hr>
<h2 align="center">condition</h2>
</td>
</tr>
</table>
<hr>
<p><A href="#Introduction">Introduction</a><br>
<A href="#Header">Header</a><br>
<A href="#Synopsis">Synopsis</a><br>
<A href="#Members">Members</a><br>
<A href="#Example">Example</a></p>
<p><a href="#Introduction">Introduction</a><br>
<a href="#Header">Header</a><br>
<a href="#Synopsis">Synopsis</a><br>
<a href="#Members">Members</a><br>
<a href="#Example">Example</a></p>
<h2><a name="Introduction">Introduction</a></h2>
<h2><a name="Introduction">Introduction</a></h2>
<p>An object of class <code>condition</code> is a synchronization primitive used to
cause a thread to wait until a particular shared-data condition (or time) is met.
A <code>condition</code> object is always used in conjunction with a mutex
object modeling a <a href="mutex_concept.html">Mutex Concept</a>. The mutex must be locked prior to waiting on the
<code>condition</code>, which is ensured by passing a lock object modeling a <a href="lock_concept.html">Lock
Concept</a> to the <code>condition</code> object's <code>wait</code> functions. While the thread is waiting on the <code>condition</code>
object,
the mutex associated with the lock is unlocked. When the thread returns
from a call to one of the <code>condition</code> object's <code>wait</code> functions,
the mutex is again locked. The tricky lock/unlock/lock sequence is performed
automatically by the <code>condition</code> object's <code>wait</code>
functions.</p>
<p>An object of class <code>condition</code> is a synchronization
primitive used to cause a thread to wait until a particular shared-data
condition (or time) is met. A <code>condition</code> object is always
used in conjunction with a mutex object modeling a <a href=
"mutex_concept.html">Mutex Concept</a>. The mutex must be locked prior
to waiting on the <code>condition</code>, which is ensured by passing a
lock object modeling a <a href="lock_concept.html">Lock Concept</a> to
the <code>condition</code> object&#39;s <code>wait</code> functions.
While the thread is waiting on the <code>condition</code> object, the
mutex associated with the lock is unlocked. When the thread returns
from a call to one of the <code>condition</code> object&#39;s <code>
wait</code> functions, the mutex is again locked. The tricky
lock/unlock/lock sequence is performed automatically by the <code>
condition</code> object&#39;s <code>wait</code> functions.</p>
<p>The <code>condition</code> type is often used to implement the <i>Monitor Object</i>
and other important patterns. See <A href="bibliography.html#Schmidt-00">[Schmidt-00]</a>
and <A href="bibliography.html#Hoare-74">[Hoare 74]</a>. Monitors are one of the most
important patterns for creating reliable multithreaded programs.</p>
<p>The <code>condition</code> type is often used to implement the <i>
Monitor Object</i> and other important patterns. See <a href=
"bibliography.html#Schmidt-00">[Schmidt-00]</a> and <a href=
"bibliography.html#Hoare-74">[Hoare 74]</a>. Monitors are one of the
most important patterns for creating reliable multithreaded
programs.</p>
<p>See <A href="definitions.html">Formal Definitions</a> for definitions of thread
states <A href="definitions.html#state">blocked</a> and
<A href="definitions.html#state">ready</a>. Note that "waiting" is a synonym
for blocked.</p>
<h2><a name="Header">Header</a></h2>
<p>See <a href="definitions.html">Formal Definitions</a> for
definitions of thread states <a href="definitions.html#state">
blocked</a> and <a href="definitions.html#state">ready</a>. Note that
&quot;waiting&quot; is a synonym for blocked.</p>
<h2><a name="Header">Header</a></h2>
<pre>
#include <A href="../../../boost/thread/condition.hpp">&lt;boost/thread/condition.hpp&gt;</a>
#include <a href=
"../../../boost/thread/condition.hpp">&lt;boost/thread/condition.hpp&gt;</a>
</pre>
<h2><a name="Synopsis">Synopsis</a></h2>
<h2><a name="Synopsis">Synopsis</a></h2>
<pre>
namespace boost {
class condition : private <A href="../../utility/utility.htm#Class noncopyable">boost::noncopyable</a> // Exposition only.
// Class condition meets the <a href="overview.html#NonCopyable">NonCopyable</a> requirement.
class condition : private <a href=
"../../utility/utility.htm#Class noncopyable">boost::noncopyable</a> // Exposition only.
// Class condition meets the <a href=
"overview.html#NonCopyable">NonCopyable</a> requirement.
{
public:
condition();
@@ -76,171 +84,170 @@ public:
void notify_all();
template &lt;typename <a href="scoped_lock.html">ScopedLock</a>&gt;
void wait(<a href="scoped_lock.html">ScopedLock</a>&amp; lock);
template &lt;typename <a href="scoped_lock.html">ScopedLock</a>, typename <A href="http://www.sgi.com/tech/stl/Predicate.html">Predicate</A>&gt;
void wait(<a href="scoped_lock.html">ScopedLock</a>&amp; lock, <A href="http://www.sgi.com/tech/stl/Predicate.html">Predicate</A> pred);
template &lt;typename <a href="scoped_lock.html">ScopedLock</a>, typename <a
href="http://www.sgi.com/tech/stl/Predicate.html">Predicate</a>&gt;
void wait(<a href="scoped_lock.html">ScopedLock</a>&amp; lock, <a href=
"http://www.sgi.com/tech/stl/Predicate.html">Predicate</a> pred);
template &lt;typename <a href="scoped_lock.html">ScopedLock</a>&gt;
bool timed_wait(<a href="scoped_lock.html">ScopedLock</a>&amp; lock, const xtime&amp; xt);
template &lt;typename <a href="scoped_lock.html">ScopedLock</a>, typename <A href="http://www.sgi.com/tech/stl/Predicate.html">Predicate</A>&gt;
bool timed_wait(<a href="scoped_lock.html">ScopedLock</a>&amp; lock, const xtime&amp; xt, <A href="http://www.sgi.com/tech/stl/Predicate.html">Predicate</A> pred);
bool timed_wait(<a href=
"scoped_lock.html">ScopedLock</a>&amp; lock, const xtime&amp; xt);
template &lt;typename <a href="scoped_lock.html">ScopedLock</a>, typename <a
href="http://www.sgi.com/tech/stl/Predicate.html">Predicate</a>&gt;
bool timed_wait(<a href=
"scoped_lock.html">ScopedLock</a>&amp; lock, const xtime&amp; xt, <a href=
"http://www.sgi.com/tech/stl/Predicate.html">Predicate</a> pred);
};
} // namespace boost
</pre>
<h2><a name="Members">Members</a></h2>
<hr>
<h3>Constructor</h3>
<h2><a name="Members">Members</a></h2>
<hr>
<h3>Constructor</h3>
<pre>
condition();
</pre>
<p><b>Effects:</b> Constructs a <code>condition</code>.</p>
<hr>
<h3>Destructor</h3>
<p><b>Effects:</b> Constructs a <code>condition</code>.</p>
<hr>
<h3>Destructor</h3>
<pre>
~condition();
</pre>
<p><b>Effects:</b> Destroys <code>*this</code>.</p>
<hr>
<h3>notify_one</h3>
<p><b>Effects:</b> Destroys <code>*this</code>.</p>
<hr>
<h3>notify_one</h3>
<pre>
void notify_one();
</pre>
<p><b>Effects:</b> If there is a thread waiting on <code>*this</code>, change
that thread's state to ready. Otherwise there is no effect.</p>
<p><b>Effects:</b> If there is a thread waiting on <code>*this</code>,
change that thread&#39;s state to ready. Otherwise there is no
effect.</p>
<p><b>Notes:</b> If more that one thread is waiting on the condition, it is
unspecified which is made ready.</p>
<hr>
<h3>notify_all</h3>
<p><b>Notes:</b> If more that one thread is waiting on the condition,
it is unspecified which is made ready.</p>
<hr>
<h3>notify_all</h3>
<pre>
void notify_all();
</pre>
<p><b>Effects:</b> Change the state of all threads waiting on <code>*this</code>
to ready. If there are no waiting threads, <code>notify_all()</code> has no effect.</p>
<hr>
<h3>wait</h3>
<p><b>Effects:</b> Change the state of all threads waiting on <code>
*this</code> to ready. If there are no waiting threads, <code>
notify_all()</code> has no effect.</p>
<hr>
<h3>wait</h3>
<pre>
template &lt;typename ScopedLock&gt;
void wait(ScopedLock&amp; lock);
</pre>
<p><b>Requires:</b> ScopedLock meets the
<A href="lock_concept.html#ScopedLock">ScopedLock</a> requirements.</p>
<p><b>Requires:</b> ScopedLock meets the <a href=
"lock_concept.html#ScopedLock">ScopedLock</a> requirements.</p>
<p><b>Effects:</b> Releases the lock on the <A href="mutex_concept.html">mutex model</a>
associated with <code>lock</code>, blocks the current thread of execution until readied
by a call to <code>this-&gt;notify_one()</code> or <code>this-&gt;notify_all()</code>,
and then reacquires the lock. All effects occur in an atomic fashion.</p>
<p><b>Effects:</b> Releases the lock on the <a href=
"mutex_concept.html">mutex model</a> associated with <code>lock</code>,
blocks the current thread of execution until readied by a call to
<code>this-&gt;notify_one()</code> or <code>
this-&gt;notify_all()</code>, and then reacquires the lock. All effects
occur in an atomic fashion.</p>
<p><b>Throws:</b> <code><A href="lock_error.html">lock_error</a></code>
if <code>!lock.locked()</code></p>
<p><b>Danger:</b> This version should always be used within a loop checking that the
state logically associated with the <code>condition</code> has become true. Without
the loop, race conditions can ensue due to possible "spurious wake ups". The second
version encapsulates this loop idiom internally and is generally the preferred method.</p>
<p><b>Throws:</b> <code><a href="lock_error.html">lock_error</a></code>
if <code>!lock.locked()</code></p>
<p><b>Danger:</b> This version should always be used within a loop
checking that the state logically associated with the <code>
condition</code> has become true. Without the loop, race conditions can
ensue due to possible &quot;spurious wake ups&quot;. The second version
encapsulates this loop idiom internally and is generally the preferred
method.</p>
<pre>
template &lt;typename ScopedLock, typename Pr&gt;
void wait(ScopedLock&amp; lock, Pr pred);
</pre>
<p><b>Requires:</b> ScopedLock meets the
<A href="lock_concept.html#ScopedLock">ScopedLock</a> requirements, return from
<code>pred()</code> convertible to bool.</p>
<p><b>Requires:</b> ScopedLock meets the <a href=
"lock_concept.html#ScopedLock">ScopedLock</a> requirements, return from
<code>pred()</code> convertible to bool.</p>
<p><b>Effects:</b> As if:</p>
<p><b>Effects:</b> As if:</p>
<code>&nbsp;&nbsp;&nbsp;while (!pred()) wait(lock)</code>
<code>
&nbsp;&nbsp;&nbsp;while (!pred()) wait(lock)
</code>
<p><b>Throws:</b> <code><A href="lock_error.html">lock_error</a></code> if
<code>!lock.locked()</code></p>
<hr>
<h3>timed_wait</h3>
<p><b>Throws:</b> <code><a href="lock_error.html">lock_error</a></code>
if <code>!lock.locked()</code></p>
<hr>
<h3>timed_wait</h3>
<pre>
template &lt;typename ScopedTimedLock&gt;
bool timed_wait(ScopedTimedLock&amp; lock, const <a href="xtime.html">xtime</a>&amp; xt);
template &lt;typename ScopedLock&gt;
bool timed_wait(ScopedLock&amp; lock, const <a href=
"xtime.html">xtime</a>&amp; xt);
</pre>
<p><b>Requires:</b> ScopedTimeLock meets the
<A href="lock_concept.html#ScopedTimedLock">ScopedTimedLock</a> requirements.</p>
<p><b>Requires:</b> ScopedLock meets the <a href=
"lock_concept.html#ScopedLock">ScopedLock</a>
requirements.</p>
<p><b>Effects:</b> Releases the lock on the <A href="mutex_concept.html">mutex model</a>
associated with the <code>lock</code>, blocks the current thread of execution until
readied by a call to <code>this-&gt;notify_one()</code> or
<code>this-&gt;notify_all()</code>, or until <code>xt</code>, and then reacquires the
lock. All effects occur in an atomic fashion.</p>
<p><b>Effects:</b> Releases the lock on the <a href=
"mutex_concept.html">mutex model</a> associated with the <code>
lock</code>, blocks the current thread of execution until readied by a
call to <code>this-&gt;notify_one()</code> or <code>
this-&gt;notify_all()</code>, or until <code>xt</code>, and then
reacquires the lock. All effects occur in an atomic fashion.</p>
<p><b>Throws:</b> <code><A href="lock_error.html">lock_error</a></code> if
<code>!lock.locked()</code></p>
<p><b>Throws:</b> <code><a href="lock_error.html">lock_error</a></code>
if <code>!lock.locked()</code></p>
<p><b>Danger:</b> This version should always be used within a loop checking that the
state logically associated with the <code>condition</code> has become true. Without
the loop, race conditions can ensue due to "spurious wake ups". The second version
encapsulates this loop idiom internally and is generally the preferred method.</p>
<p><b>Returns:</b> <code>false</code> if <code>xt</code> is reached, otherwise
<code>true</code>.</p>
<p><b>Danger:</b> This version should always be used within a loop
checking that the state logically associated with the <code>
condition</code> has become true. Without the loop, race conditions can
ensue due to &quot;spurious wake ups&quot;. The second version
encapsulates this loop idiom internally and is generally the preferred
method.</p>
<p><b>Returns:</b> <code>false</code> if <code>xt</code> is reached,
otherwise <code>true</code>.</p>
<pre>
template &lt;typename ScopedTimedLock, typename Pr&gt;
bool timed_wait(ScopedTimedLock&amp; lock, const <a href="xtime.html">xtime</a>&amp; xt, Pr pred);
template &lt;typename ScopedLock, typename Pr&gt;
bool timed_wait(ScopedLock&amp; lock, const <a href=
"xtime.html">xtime</a>&amp; xt, Pr pred);
</pre>
<p><b>Requires: </b>ScopedTimeLock meets the
<A href="lock_concept.html#ScopedTimedLock">ScopedTimedLock</a> requirements,
return from <code>pred()</code> convertible to bool.</p>
<p><b>Requires:</b> ScopedLock meets the <a href=
"lock_concept.html#ScopedLock">ScopedLock</a> requirements,
return from <code>pred()</code> convertible to bool.</p>
<p><b>Effects: </b>As if:</p>
<p><b>Effects:</b> As if:</p>
<code>&nbsp;&nbsp;&nbsp;while (!pred())<br>
&nbsp;&nbsp;&nbsp;{<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;if (!timed_wait(lock, xt))<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;return
false;<br>
&nbsp;&nbsp;&nbsp;}</code>
<code>
&nbsp;&nbsp;&nbsp;while (!pred())<br>
&nbsp;&nbsp;&nbsp;{<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;if (!timed_wait(lock, xt))<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;return false;<br>
&nbsp;&nbsp;&nbsp;}
</code>
<p><b>Throws:</b> <code><a href="lock_error.html">lock_error</a></code>
if <code>!lock.locked()</code></p>
<p><b>Throws:</b> <code><A href="lock_error.html">lock_error</a></code> if
<code>!lock.locked()</code></p>
<p><b>Returns:</b> <code>false</code> if <code>xt</code> is reached, otherwise
<code>true</code>.</p>
<hr>
<h2><a name="Example">Example Usage</a></h2>
<p><b>Returns:</b> <code>false</code> if <code>xt</code> is reached,
otherwise <code>true</code>.</p>
<hr>
<h2><a name="Example">Example Usage</a></h2>
<pre>
#include &lt;iostream&gt;
#include &lt;vector&gt;
#include <A href="../../../boost/utility.hpp">&lt;boost/utility.hpp&gt;</a>
#include <A href="../../../boost/thread/condition.hpp">&lt;boost/thread/condition.hpp&gt;</a>
#include <A href="../../../boost/thread/thread.hpp">&lt;boost/thread/thread.hpp&gt;</a>
#include <a href="../../../boost/utility.hpp">&lt;boost/utility.hpp&gt;</a>
#include <a href=
"../../../boost/thread/condition.hpp">&lt;boost/thread/condition.hpp&gt;</a>
#include <a href=
"../../../boost/thread/thread.hpp">&lt;boost/thread/thread.hpp&gt;</a>
class bounded_buffer : private boost::noncopyable
{
@@ -306,8 +313,7 @@ int main(int, char*[])
}
</pre>
<p>Typical output (dependent on scheduling policies) is:</p>
<p>Typical output (dependent on scheduling policies) is:</p>
<pre>
sent: 0
sent: 1
@@ -320,14 +326,13 @@ received: 3
sent: 4
received: 4
</pre>
<hr>
<hr>
<p>Revised
<!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->05 November, 2001<!--webbot bot="Timestamp" endspan i-checksum="39359" --></p>
<p>Revised <!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->01 October, 2001<!--webbot bot="Timestamp" endspan i-checksum="38291" -->
</p>
<p><i>© Copyright <A href="mailto:williamkempf@hotmail.com">William E. Kempf</a>
2001 all rights reserved.</i></p>
</body>
<p><i>&copy; Copyright <a href="mailto:williamkempf@hotmail.com">
William E. Kempf</a> 2001 all rights reserved.</i></p>
</body>
</html>

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@@ -1,103 +0,0 @@
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<meta name="keywords" content="threads, BTL, thread library, C++">
<title>Boost.Threads, Configuration Information</title>
</head>
<body bgcolor="#FFFFFF" link="#0000FF" vlink="#800080">
<table border="0" cellpadding="7" cellspacing="0" width="100%">
<tr>
<td valign="top" width="300">
<h3><img src="../../../c++boost.gif" alt="C++ Boost" width="277" height="86"></h3>
</td>
<td valign="top">
<h1 align="center">Boost.Threads</h1>
<h2 align="center">Configuration Information</h2>
</td>
</tr>
</table>
<hr>
<p><b>Boost.Threads</b> uses several configuration macros in <a href="../../config/config.htm"> &lt;boost/config.hpp&gt;</a>.
These macros are documented here. Most of the macros are
of interest only to developers attempting to provide new implementations of <b>Boost.Threads</b>.
The one exception to this is BOOST_HAS_THREADS.</p>
<table cellspacing="10" width="100%">
<tr>
<td valign="top">
<b>Macro</b>
</td>
<td valign="top">
<b>Meaning</b>
</td>
</tr>
<tr>
<td valign="top">
BOOST_HAS_THREADS
</td>
<td valign="top">
Indicates that threading support is available. This means both that there is a
platform specific implementation for <b>Boost.Threads</b> and that threading
support has been enabled in a platform specific manner. For instance, on the
Win32 platform there's an implementation for <b>Boost.Threads</b> but unless
the program is compiled against one of the multi-threading runtimes
(often determined by the
compiler predefining the macro _MT) the
BOOST_HAS_THREADS macro remains undefined.
</td>
</tr>
<tr>
<td valign="top">
BOOST_HAS_WINTHREADS
</td>
<td valign="top">
Indicates that the platform has the Microsoft Win32 threading libraries,
and that they should be used
to implement <b>Boost.Threads</b>.
</td>
</tr>
<tr>
<td valign="top">
BOOST_HAS_PTHREADS
</td>
<td valign="top">
Indicates that the platform has the POSIX pthreads libraries, and that
they should be used
to implement <b>Boost.Threads</b>.
</td>
</tr>
<tr>
<td valign="top">
BOOST_HAS_FTIME
</td>
<td valign="top">
Indicates that the implementation should use GetSystemTimeAsFileTime() and
the FILETIME type to calculate the current time. This is an implementation
detail used by boost::detail::getcurtime().
</td>
</tr>
<tr>
<td valign="top">
BOOST_HAS_GETTTIMEOFDAY
</td>
<td valign="top">
Indicates that the implementation should use gettimeofday() to calculate the
current time. This is an implementation detail used by boost::detail::getcurtime().
</td>
</tr>
</table>
<hr>
<p>Revised <!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->01 October, 2001<!--webbot bot="Timestamp" endspan i-checksum="38291" -->
</p>
<p><i>© Copyright <a href="mailto:williamkempf@hotmail.com">William E. Kempf</a>
2001 all rights reserved.</i></p>
</body>
</html>

94
doc/configuration.html Normal file
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@@ -0,0 +1,94 @@
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<link rel="stylesheet" type="text/css" href="../../../boost.css">
<title>Boost.Threads - Configuration</title>
</head>
<body link="#0000ff" vlink="#800080">
<table border="0" cellpadding="7" cellspacing="0" width="100%" summary=
"header">
<tr>
<td valign="top" width="300">
<h3><a href="../../../index.htm"><img height="86" width="277" alt="C++ Boost" src="../../../c++boost.gif" border="0"></a></h3>
</td>
<td valign="top">
<h1 align="center">Boost.Threads</h1>
<h2 align="center">Configuration</h2>
</td>
</tr>
</table>
<hr>
<dl class="page-index">
<dt><a href="#introduction">Introduction</a></dt>
<dt><a href="#lib-defined-public">Public Library Defined Macros</a></dt>
<dt><a href="#lib-defined-impl">Library Defined Implementation Macros</a></dt>
</dl>
<h2><a name="introduction"></a>Introduction</h2>
<p><b>Boost.Threads</b> uses several configuration macros in <a href="../../config/config.htm">&lt;boost/config.hpp&gt;</a>,
as well as configuration macros meant to be supplied by the application. These
macros are documented here.</p>
<h2><a name="lib-defined-public"></a>Public Library Defined Macros</h2>
<p>These macros are defined by <b>Boost.Threads</b> but are expected to be used by application
code.</p>
<table summary="public library defined macros" cellspacing="10" width="100%">
<tr>
<td><b>Macro</b></td>
<td><b>Meaning</b></td>
</tr>
<tr>
<td>BOOST_HAS_THREADS</td>
<td>Indicates that threading support is available. This means both that there
is a platform specific implementation for <b>Boost.Threads</b> and that
threading support has been enabled in a platform specific manner. For instance,
on the Win32 platform there&#39;s an implementation for <b>Boost.Threads</b>
but unless the program is compiled against one of the multi-threading runtimes
(often determined by the compiler predefining the macro _MT) the BOOST_HAS_THREADS
macro remains undefined.</td>
</tr>
</table>
<h2><a name="lib-defined-impl"></a>Library Defined Implementation Macros</h2>
<p>These macros are defined by <b>Boost.Threads</b> and are implementation details of interest
only to implementers.</p>
<table summary="library defined implementation macros" cellspacing="10" width="100%">
<tr>
<td><b>Macro</b></td>
<td><b>Meaning</b></td>
</tr>
<tr>
<td>BOOST_HAS_WINTHREADS</td>
<td>Indicates that the platform has the Microsoft Win32 threading libraries,
and that they should be used to implement <b>Boost.Threads</b>.</td>
</tr>
<tr>
<td>BOOST_HAS_PTHREADS</td>
<td>Indicates that the platform has the POSIX pthreads libraries, and that
they should be used to implement <b>Boost.Threads</b>.</td>
</tr>
<tr>
<td>BOOST_HAS_FTIME</td>
<td>Indicates that the implementation should use GetSystemTimeAsFileTime()
and the FILETIME type to calculate the current time. This is an implementation
detail used by boost::detail::getcurtime().</td>
</tr>
<tr>
<td>BOOST_HAS_GETTTIMEOFDAY</td>
<td>Indicates that the implementation should use gettimeofday() to calculate
the current time. This is an implementation detail used by boost::detail::getcurtime().</td>
</tr>
</table>
<hr>
<p>Revised
<!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->
05 November, 2001
<!--webbot bot="Timestamp" endspan i-checksum="39359" -->
</p>
<p><i>&copy; Copyright <a href="mailto:wekempf@cox.net">William E. Kempf</a> 2001-2002.
All Rights Reserved.</i></p>
<p>Permission to use, copy, modify, distribute and sell this software and its
documentation for any purpose is hereby granted without fee, provided that the
above copyright notice appear in all copies and that both that copyright notice
and this permission notice appear in supporting documentation. William E. Kempf
makes no representations about the suitability of this software for any purpose.
It is provided &quot;as is&quot; without express or implied warranty.</p>
</body>
</html>

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@@ -1,244 +1,348 @@
<html>
<head>
<meta http-equiv="Content-Language" content="en-us">
<meta http-equiv="Content-Type" content=
"text/html; charset=windows-1252">
<meta name="GENERATOR" content="Microsoft FrontPage 4.0">
<meta name="ProgId" content="FrontPage.Editor.Document">
<head>
<meta http-equiv="Content-Language" content="en-us">
<meta http-equiv="Content-Type" content="text/html; charset=windows-1252">
<meta name="GENERATOR" content="Microsoft FrontPage 4.0">
<meta name="ProgId" content="FrontPage.Editor.Document">
<title>Boost.Threads Definitions</title>
</head>
<title>Boost.Threads Definitions</title>
</head>
<body bgcolor="#FFFFFF">
<body bgcolor="#FFFFFF">
<table summary="header" border="0" cellpadding="7" cellspacing="0"
width="100%">
<tr>
<td valign="top" width="300">
<h3><img src="../../../c++boost.gif" alt="C++ Boost" width=
"277" height="86"></h3>
</td>
<table border="0" cellpadding="7" cellspacing="0" width="100%">
<tr>
<td valign="top" width="300">
<h3><img src="../../../c++boost.gif" alt="C++ Boost" width="277" height="86"></h3>
</td>
<td valign="top">
<h1 align="center">Boost.Threads</h1>
<h2 align="center"> Definitions</h2>
</td>
</tr>
</table>
<h2>Introduction</h2>
<p>The definitions are given in terms of the <a href="bibliography.html#ISO-98"> C++ Standard</a>.&nbsp; References to the standard
are in the form [1.2.3/4], which
represents the section number, with the paragraph number following the &quot;/&quot;.</p>
<p>Because the definitions are written in something akin to
&quot;standardese&quot;, they can be difficult to understand.&nbsp; The intent
isn't to confuse, but rather to clarify the additional requirements
Boost.Threads places on a C++ implementation as defined by the C++ Standard.</p>
<h2>Definitions</h2>
<h3>Thread</h3>
<p>Thread is short for &quot;thread of execution&quot;. A thread of execution is an execution environment [1.9/7] within the execution environment
of a C++ program [1.9]. The main() function [3.6.1] of the program is the
initial function of the initial thread. A program in a multi-threading
environment always has an initial thread even if the program explicitly creates
no additional threads.</p>
<p>Unless otherwise specified, each thread shares all aspects of its execution environment with
other threads in the program. Shared aspects of the execution environment
include, but are not limited to, the following:</p>
<ul>
<li>Static storage duration (static, extern) objects [3.7.1].</li>
</ul>
<ul>
<li>Dynamic storage duration (heap) objects [3.7.3].&nbsp; Thus each memory
allocation will return a unique addresses, regardless of the thread making
the allocation request.</li>
</ul>
<ul>
<li>Automatic storage duration (stack) objects [3.7.2] accessed via pointer or
reference from another thread.</li>
</ul>
<ul>
<li>Resources provided by the operating
system.&nbsp; For example, files.</li>
</ul>
<ul>
<li>The program itself.&nbsp; In other words, each thread is executing some
function of the same program, not a totally different program.</li>
</ul>
<p>Each thread has its own:</p>
<ul>
<li>Registers and current execution sequence (program counter) [1.9/5].</li>
</ul>
<ul>
<li>Automatic storage duration (stack) objects [3.7.2].</li>
</ul>
<h3><a name="Thread-safe">Thread-safe</a></h3>
<p>A program is thread-safe if it has no <a href="#Race condition">race
conditions</a>, does not <a href="#Deadlock">deadlock</a>, and has no <a href="#Priority failure">priority
failures</a>.</p>
<p>Note that thread-safety does not necessarily imply efficiency, and than while
some thread-safety violations can be determined statically at compile time, many
thread-safety errors can only only be detected at runtime.</p>
<h3>Thread <a name="State">State</a></h3>
<p>During the lifetime of a thread, it shall be in one of the following
states:</p>
<table border="1" cellpadding="5">
<tr>
<td><b>State</b></td>
<td><b>Description</b></td>
</tr>
<tr>
<td>Ready</td>
<td>Ready to run, but waiting for a processor.</td>
</tr>
<tr>
<td>Running</td>
<td>Currently executing on a processor. Zero or more threads may be running
at any time, with a maximum equal to the number of processors.&nbsp;</td>
</tr>
<tr>
<td>Blocked</td>
<td>Waiting for some resource other than a processor which is not currently
available, or for the completion of calls to library functions [1.9/6].
The term &quot;waiting&quot; is synonymous for &quot;blocked&quot;</td>
</tr>
<tr>
<td>Terminated</td>
<td>Finished execution but not yet detached or joined.</td>
</tr>
</table>
<p>Thread state transitions shall occur only as specified:</p>
<table border="1" cellpadding="5">
<tr>
<td><b>From</b></td>
<td><b>To</b></td>
<td><b>Cause</b></td>
</tr>
<tr>
<td>
<p align="left">[none]</td>
<td>Ready</td>
<td>Thread is created by a call to a library function.&nbsp; In the case of
the initial thread, creation is implicit and occurs during the startup of
the main() function [3.6.1].</td>
</tr>
<tr>
<td>Ready</td>
<td>Running</td>
<td>Processor becomes available.</td>
</tr>
<tr>
<td>Running</td>
<td>Ready</td>
<td>Thread preempted.</td>
</tr>
<tr>
<td>Running</td>
<td>Blocked</td>
<td>Thread calls a library function which waits for a resource or for the
completion of I/O.</td>
</tr>
<tr>
<td>Running</td>
<td>Terminated</td>
<td>Thread returns from its initial function, calls a thread termination
library function, or is cancelled by some other thread calling a thread
termination library function.</td>
</tr>
<tr>
<td>Blocked</td>
<td>Ready</td>
<td>The resource being waited for becomes available, or the blocking library
function completes.</td>
</tr>
<tr>
<td>Terminated</td>
<td>[none]</td>
<td>Thread is detached or joined by some other thread calling the
appropriate library function, or by program termination [3.6.3].</td>
</tr>
</table>
<p>[Note: if a suspend() function is added to the threading library, additional
transitions to the blocked state will have to be added to the above table.]</p>
<h3><a name="Race condition">Race condition</a></h3>
<p>A race condition is what occurs when multiple threads read and
write to the same memory without proper synchronization, resulting in an
incorrect value being read or written.&nbsp; The result of a race condition may
be a bit pattern which isn't even a valid value for the data type. A race
condition results in undefined behavior [1.3.12].</p>
<p>Race conditions can be prevented by serializing memory access
using the tools provided by Boost.Threads.&nbsp;</p>
<h3><a name="Deadlock">Deadlock</a></h3>
<p>Deadlock is an execution state where for some set of threads, each thread in
the set is blocked waiting for some action by one of the other threads in the
set. Since each is waiting on the others, none will ever become ready again.</p>
<h3><a name="Priority failure">Priority failure</a></h3>
<p>A priority failure (such as priority inversion or infinite overtaking) occurs
when threads executed in such a sequence that required work is not performed in
time to be useful.</p>
<h2>Memory visibility between threads</h2>
<p>An address [1.7] shall always point to the same memory byte, regardless of the
thread or processor dereferencing the address.</p>
<p>An object [1.8, 1.9] is accessible from multiple threads if it is of
static storage duration (static, extern) [3.7.1], or if a pointer or reference to
it is explicitly or
implicitly dereferenced in multiple threads.</p>
<p>For an object accessible from multiple threads, the value of the object
accessed from one thread may be indeterminate or different than the value
accessed from another thread, except under the conditions specified in the following
table.&nbsp;&nbsp; For the same row of the table, the value of an object
accessible at the indicated sequence point in thread A will be determinate and the
same if accessed at or after the indicated sequence point in thread B, provided
the object is not otherwise modified. In the table, the
&quot;sequence point at a call&quot; is the sequence point after the evaluation
of all function arguments [1.9/17], while the &quot;sequence point after a
call&quot; is the sequence point after the copying of the returned
value...&quot; [1.9/17].</p>
<table border="1" cellpadding="5">
<tr>
<td align="center"><b>Thread A</b></td>
<td align="center"><b>Thread B</b></td>
</tr>
<tr>
<td>The sequence point at a call to a library thread-creation
function.&nbsp;</td>
<td>The first sequence point of the initial function in the new thread
created by the Thread A call.</td>
</tr>
<tr>
<td>The sequence point at a call to a library function which locks a mutex,
directly or by waiting for a condition variable.</td>
<td>The sequence point after a call to a library function which unlocks the
same mutex.</td>
</tr>
<tr>
<td>The last sequence point before thread termination.</td>
<td>The sequence point after a call to a library function which joins the
terminated thread.</td>
</tr>
<tr>
<td>The sequence point at a call to a library function which signals or
broadcasts a condition variable.</td>
<td>The sequence point after the call to the library function which was
waiting on that same condition variable or signal.</td>
</tr>
</table>
<p>The architecture of the execution environment and the observable behavior of
the abstract machine [1.9] shall be the same on all processors.</p>
<p>The latitude granted by the C++ standard for an implementation to alter the
definition of observable behavior of the abstract machine to include additional library I/O
functions [1.9/6] is extended to include threading library functions.</p>
<p>When an exception is thrown and there is no matching exception handler in the
same thread, behavior is undefined.&nbsp; The preferred behavior is the same as when there is no matching exception handler
in a program [15.3/9].&nbsp; That is, terminate() is called, and it is implementation defined
whether or not the stack is unwound.</p>
<h2><a name="Acknowledgements">Acknowledgements</a></h2>
<p>This document has been much improved by the incorporation of comments from
William Kempf.</p>
<p>The visibility rules are based on <a href="bibliography.html#Butenhof-97">[Butenhof
97]</a>.&nbsp;</p>
<hr>
<p>Revised <!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %b %Y" startspan -->01 Oct 2001<!--webbot bot="Timestamp" endspan i-checksum="14990" -->
</p>
<p>© Copyright Beman Dawes, 2001</p>
<p>&nbsp;</p>
<p>&nbsp;</p>
<p>&nbsp;</p>
<td valign="top">
<h1 align="center">Boost.Threads</h1>
</body>
<h2 align="center">Definitions</h2>
</td>
</tr>
</table>
<h2>Introduction</h2>
<p>The definitions are given in terms of the <a href=
"bibliography.html#ISO-98">C++ Standard</a>. References to the standard
are in the form [1.2.3/4], which represents the section number, with
the paragraph number following the &quot;/&quot;.</p>
<p>Because the definitions are written in something akin to
&quot;standardese&quot;, they can be difficult to understand. The
intent isn&#39;t to confuse, but rather to clarify the additional
requirements Boost.Threads places on a C++ implementation as defined by
the C++ Standard.</p>
<h2>Definitions</h2>
<h3>Thread</h3>
<p>Thread is short for &quot;thread of execution&quot;. A thread of
execution is an execution environment [1.9/7] within the execution
environment of a C++ program [1.9]. The main() function [3.6.1] of the
program is the initial function of the initial thread. A program in a
multi-threading environment always has an initial thread even if the
program explicitly creates no additional threads.</p>
<p>Unless otherwise specified, each thread shares all aspects of its
execution environment with other threads in the program. Shared aspects
of the execution environment include, but are not limited to, the
following:</p>
<ul>
<li>Static storage duration (static, extern) objects [3.7.1].</li>
</ul>
<ul>
<li>Dynamic storage duration (heap) objects [3.7.3]. Thus each
memory allocation will return a unique addresses, regardless of the
thread making the allocation request.</li>
</ul>
<ul>
<li>Automatic storage duration (stack) objects [3.7.2] accessed via
pointer or reference from another thread.</li>
</ul>
<ul>
<li>Resources provided by the operating system. For example,
files.</li>
</ul>
<ul>
<li>The program itself. In other words, each thread is executing
some function of the same program, not a totally different
program.</li>
</ul>
<p>Each thread has its own:</p>
<ul>
<li>Registers and current execution sequence (program counter)
[1.9/5].</li>
</ul>
<ul>
<li>Automatic storage duration (stack) objects [3.7.2].</li>
</ul>
<h3><a name="Thread-safe">Thread-safe</a></h3>
<p>A program is thread-safe if it has no <a href="#Race condition">race
conditions</a>, does not <a href="#Deadlock">deadlock</a>, and has no
<a href="#Priority failure">priority failures</a>.</p>
<p>Note that thread-safety does not necessarily imply efficiency, and
than while some thread-safety violations can be determined statically
at compile time, many thread-safety errors can only only be detected at
runtime.</p>
<h3>Thread <a name="State">State</a></h3>
<p>During the lifetime of a thread, it shall be in one of the following
states:</p>
<table summary="thread states" border="1" cellpadding="5">
<tr>
<td><b>State</b></td>
<td><b>Description</b></td>
</tr>
<tr>
<td>Ready</td>
<td>Ready to run, but waiting for a processor.</td>
</tr>
<tr>
<td>Running</td>
<td>Currently executing on a processor. Zero or more threads
may be running at any time, with a maximum equal to the number
of processors.</td>
</tr>
<tr>
<td>Blocked</td>
<td>Waiting for some resource other than a processor which is
not currently available, or for the completion of calls to
library functions [1.9/6]. The term &quot;waiting&quot; is
synonymous for &quot;blocked&quot;</td>
</tr>
<tr>
<td>Terminated</td>
<td>Finished execution but not yet detached or joined.</td>
</tr>
</table>
<p>Thread state transitions shall occur only as specified:</p>
<table summary="state transitions" border="1" cellpadding="5">
<tr>
<td><b>From</b></td>
<td><b>To</b></td>
<td><b>Cause</b></td>
</tr>
<tr>
<td>
<p align="left">[none]</p>
</td>
<td>Ready</td>
<td>Thread is created by a call to a library function. In the
case of the initial thread, creation is implicit and occurs
during the startup of the main() function [3.6.1].</td>
</tr>
<tr>
<td>Ready</td>
<td>Running</td>
<td>Processor becomes available.</td>
</tr>
<tr>
<td>Running</td>
<td>Ready</td>
<td>Thread preempted.</td>
</tr>
<tr>
<td>Running</td>
<td>Blocked</td>
<td>Thread calls a library function which waits for a resource
or for the completion of I/O.</td>
</tr>
<tr>
<td>Running</td>
<td>Terminated</td>
<td>Thread returns from its initial function, calls a thread
termination library function, or is cancelled by some other
thread calling a thread termination library function.</td>
</tr>
<tr>
<td>Blocked</td>
<td>Ready</td>
<td>The resource being waited for becomes available, or the
blocking library function completes.</td>
</tr>
<tr>
<td>Terminated</td>
<td>[none]</td>
<td>Thread is detached or joined by some other thread calling
the appropriate library function, or by program termination
[3.6.3].</td>
</tr>
</table>
<p>[Note: if a suspend() function is added to the threading library,
additional transitions to the blocked state will have to be added to
the above table.]</p>
<h3><a name="Race condition">Race condition</a></h3>
<p>A race condition is what occurs when multiple threads read and write
to the same memory without proper synchronization, resulting in an
incorrect value being read or written. The result of a race condition
may be a bit pattern which isn&#39;t even a valid value for the data
type. A race condition results in undefined behavior [1.3.12].</p>
<p>Race conditions can be prevented by serializing memory access using
the tools provided by Boost.Threads.</p>
<h3><a name="Deadlock">Deadlock</a></h3>
<p>Deadlock is an execution state where for some set of threads, each
thread in the set is blocked waiting for some action by one of the
other threads in the set. Since each is waiting on the others, none
will ever become ready again.</p>
<h3><a name="Priority failure">Priority failure</a></h3>
<p>A priority failure (such as priority inversion or infinite
overtaking) occurs when threads executed in such a sequence that
required work is not performed in time to be useful.</p>
<h2>Memory visibility between threads</h2>
<p>An address [1.7] shall always point to the same memory byte,
regardless of the thread or processor dereferencing the address.</p>
<p>An object [1.8, 1.9] is accessible from multiple threads if it is of
static storage duration (static, extern) [3.7.1], or if a pointer or
reference to it is explicitly or implicitly dereferenced in multiple
threads.</p>
<p>For an object accessible from multiple threads, the value of the
object accessed from one thread may be indeterminate or different than
the value accessed from another thread, except under the conditions
specified in the following table. For the same row of the table, the
value of an object accessible at the indicated sequence point in thread
A will be determinate and the same if accessed at or after the
indicated sequence point in thread B, provided the object is not
otherwise modified. In the table, the &quot;sequence point at a
call&quot; is the sequence point after the evaluation of all function
arguments [1.9/17], while the &quot;sequence point after a call&quot;
is the sequence point after the copying of the returned value...&quot;
[1.9/17].</p>
<table summary="memory visibility" border="1" cellpadding="5">
<tr>
<td align="center"><b>Thread A</b></td>
<td align="center"><b>Thread B</b></td>
</tr>
<tr>
<td>The sequence point at a call to a library thread-creation
function.</td>
<td>The first sequence point of the initial function in the new
thread created by the Thread A call.</td>
</tr>
<tr>
<td>The sequence point at a call to a library function which
locks a mutex, directly or by waiting for a condition
variable.</td>
<td>The sequence point after a call to a library function which
unlocks the same mutex.</td>
</tr>
<tr>
<td>The last sequence point before thread termination.</td>
<td>The sequence point after a call to a library function which
joins the terminated thread.</td>
</tr>
<tr>
<td>The sequence point at a call to a library function which
signals or broadcasts a condition variable.</td>
<td>The sequence point after the call to the library function
which was waiting on that same condition variable or
signal.</td>
</tr>
</table>
<p>The architecture of the execution environment and the observable
behavior of the abstract machine [1.9] shall be the same on all
processors.</p>
<p>The latitude granted by the C++ standard for an implementation to
alter the definition of observable behavior of the abstract machine to
include additional library I/O functions [1.9/6] is extended to include
threading library functions.</p>
<p>When an exception is thrown and there is no matching exception
handler in the same thread, behavior is undefined. The preferred
behavior is the same as when there is no matching exception handler in
a program [15.3/9]. That is, terminate() is called, and it is
implementation defined whether or not the stack is unwound.</p>
<h2><a name="Acknowledgements">Acknowledgements</a></h2>
<p>This document has been much improved by the incorporation of
comments from William Kempf.</p>
<p>The visibility rules are based on <a href=
"bibliography.html#Butenhof-97">[Butenhof 97]</a>.</p>
<hr>
<p>Revised
<!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %b %Y" startspan -->05 Nov 2001<!--webbot bot="Timestamp" endspan i-checksum="15246" --></p>
<p>&copy; Copyright Beman Dawes, 2001</p>
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<h1 align="center">Boost.Threads</h1>
<h2 align="center">Frequently Asked Questions</h2>
</td>
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</table>
<td valign="top">
<h1 align="center">Boost.Threads</h1>
<hr>
<h2 align="center">Frequently Asked Questions</h2>
</td>
</tr>
</table>
<hr>
<h2>1. Are lock objects <a href="definitions.html#Thread-safe">thread-safe</a>?</h2>
<h2>1. Are lock objects <a href="definitions.html#Thread-safe">
thread-safe</a>?</h2>
<p><b>No!</b> Lock objects are not meant to be shared between threads. They are meant to
be short lived objects created on automatic storage within a code block. Any other usage
is just likely to lead to errors and won't really be of actual benefit any way. Share
<a href="mutex_concept.html">mutexes</a>, not locks. For more information see the
<a href="rationale.html#lock_objects">rationale</a> behind the design for lock objects.</p>
<p><b>No!</b> Lock objects are not meant to be shared between threads.
They are meant to be short lived objects created on automatic storage
within a code block. Any other usage is just likely to lead to errors
and won&#39;t really be of actual benefit any way. Share <a href=
"mutex_concept.html">mutexes</a>, not locks. For more information see
the <a href="rationale.html#lock_objects">rationale</a> behind the
design for lock objects.</p>
<h2>2a. Why was Boost.Threads modeled after (specific library name)?</h2>
<h2>2a. Why was Boost.Threads modeled after (specific library
name)?</h2>
<p>It wasn't. Boost.Threads was designed from scratch. Extensive design
discussions involved numerous people representing a wide range of experience across
many platforms. To ensure portability, the initial implements were done in
parallel using POSIX Threads and theWin32 threading API. But the Boost.Threads
design is very much in the spirit of C++, and thus doesn't model such C based
APIs.</p>
<p>It wasn&#39;t. Boost.Threads was designed from scratch. Extensive
design discussions involved numerous people representing a wide range
of experience across many platforms. To ensure portability, the initial
implements were done in parallel using POSIX Threads and theWin32
threading API. But the Boost.Threads design is very much in the spirit
of C++, and thus doesn&#39;t model such C based APIs.</p>
<h2>2b. Why wasn't Boost.Threads modeled after (specific library name)?</h2>
<h2>2b. Why wasn&#39;t Boost.Threads modeled after (specific library
name)?</h2>
<p>Existing C++ libraries either seemed dangerous (often failing to take
advantage of prior art to reduce errors) or had excessive dependencies on
library components unrelated to threading. Existing C libraries couldn't meet
our C++ requirements, and were also missing certain features. For
instance, POSIX threads doesn't support a maximum value for semaphores.
The WIN32 thread API lacks condition variables, even though these are critical
for the important Monitor pattern <a href="bibliography.html#Schmidt-00">[Schmidt
00]</a>.</p>
<p>Existing C++ libraries either seemed dangerous (often failing to
take advantage of prior art to reduce errors) or had excessive
dependencies on library components unrelated to threading. Existing C
libraries couldn&#39;t meet our C++ requirements, and were also missing
certain features. For instance, the WIN32 thread API lacks condition
variables, even though these are critical for the important Monitor
pattern <a href="bibliography.html#Schmidt-00">[Schmidt 00]</a>.</p>
<h2>3. Why do <a href="mutex_concept.html"> Mutexes</a> have noncopyable semantics?</h2>
<h2>3. Why do <a href="mutex_concept.html">Mutexes</a> have noncopyable
semantics?</h2>
<p>To ensure that <a href="definitions.html#Deadlock"> deadlocks</a> don't occur. The only logical form of copy would be to
use some sort of shallow copy semantics in which multiple mutex objects could refer
to the same mutex state. This means that if ObjA has a mutex object as part of its state
and ObjB is copy constructed from it, then when ObjB::foo() locks the mutex it has effectively
locked ObjA as well. This behavior can result in deadlock. Other
copy semantics result in similar problems (if you think you can prove this to
be wrong then supply us with an alternative and we'll reconsider).</p>
<p>To ensure that <a href="definitions.html#Deadlock">deadlocks</a>
don&#39;t occur. The only logical form of copy would be to use some
sort of shallow copy semantics in which multiple mutex objects could
refer to the same mutex state. This means that if ObjA has a mutex
object as part of its state and ObjB is copy constructed from it, then
when ObjB::foo() locks the mutex it has effectively locked ObjA as
well. This behavior can result in deadlock. Other copy semantics result
in similar problems (if you think you can prove this to be wrong then
supply us with an alternative and we&#39;ll reconsider).</p>
<h2>4. How can you prevent <a href="definitions.html#Deadlock"> deadlock</a> from occurring when a thread must lock multiple
mutexes?</h2>
<h2>4. How can you prevent <a href="definitions.html#Deadlock">
deadlock</a> from occurring when a thread must lock multiple
mutexes?</h2>
<p>Always lock them in the same order. One easy way of doing this is to use
each mutex's address to determine the order in which they are locked. A future
Boost.Threads concept may wrap this pattern up in a reusable class.</p>
<p>Always lock them in the same order. One easy way of doing this is to
use each mutex&#39;s address to determine the order in which they are
locked. A future Boost.Threads concept may wrap this pattern up in a
reusable class.</p>
<h2>5. Don't noncopyable <a href="mutex_concept.html"> mutex</a> semantics mean that a
class with a mutex member will be noncopyable as well?</h2>
<p>No, but what it does mean is that the compiler can't generate a copy constructor
and assignment operator, so they will have to be coded explicitly. This is a
<b>good thing</b>, however, since the compiler generated operations would not
be <a href="definitions.html#Thread-safe">thread-safe</a>. The following is a
simple example of a class with copyable semantics and internal synchronization through
a mutex member.</p>
<h2>5. Don&#39;t noncopyable <a href="mutex_concept.html">mutex</a>
semantics mean that a class with a mutex member will be noncopyable as
well?</h2>
<p>No, but what it does mean is that the compiler can&#39;t generate a
copy constructor and assignment operator, so they will have to be coded
explicitly. This is a <b>good thing</b>, however, since the compiler
generated operations would not be <a href=
"definitions.html#Thread-safe">thread-safe</a>. The following is a
simple example of a class with copyable semantics and internal
synchronization through a mutex member.</p>
<pre>
class counter
{
@@ -127,48 +139,55 @@ private:
};
</pre>
<h2>6. How can you lock a <a href="mutex_concept.html"> mutex</a> member in a const member function, in order to
implement the Monitor Pattern?</h2>
<h2>6. How can you lock a <a href="mutex_concept.html">mutex</a> member
in a const member function, in order to implement the Monitor
Pattern?</h2>
<p>The Monitor Pattern mutex <a href="bibliography.html#Schmidt-00">[Schmidt
00]</a> should simply be declared as mutable. See the example code above. The internal state of mutex
types could have been made mutable, with all lock calls made via const
functions, but
this does a poor job of documenting the actual semantics. Declaring a mutex member
as mutable clearly documentations the intended semantics.</p>
<p>The Monitor Pattern mutex <a href="bibliography.html#Schmidt-00">
[Schmidt 00]</a> should simply be declared as mutable. See the example
code above. The internal state of mutex types could have been made
mutable, with all lock calls made via const functions, but this does a
poor job of documenting the actual semantics. Declaring a mutex member
as mutable clearly documentations the intended semantics.</p>
<h2>7. Why supply <a href="condition.html">condition variables</a> rather than <a href="rationale.html#Events">
event variables</a>?</h2>
<h2>7. Why supply <a href="condition.html">condition variables</a>
rather than <a href="rationale.html#Events">event variables</a>?</h2>
<p>Condition variables result in user code much less prone to <a href="definitions.html#Race condition">race
conditions</a> than event variables. See <a href="rationale.html#Events">Rationale</a>
for analysis. Also see <a href="bibliography.html#Hoare-74">[Hoare74]</a>
and <a href="bibliography.html#Schmidt-00">[Schmidt
00]</a>.</p>
<p>Condition variables result in user code much less prone to <a href=
"definitions.html#Race condition">race conditions</a> than event
variables. See <a href="rationale.html#Events">Rationale</a> for
analysis. Also see <a href="bibliography.html#Hoare-74">[Hoare74]</a>
and <a href="bibliography.html#Schmidt-00">[Schmidt 00]</a>.</p>
<h2>8. Why isn't thread cancellation or termination provided?</h2>
<h2>8. Why isn&#39;t thread cancellation or termination provided?</h2>
<p>There's a valid need for thread termination, so at some point Boost.Threads
probably will include it, but only after we can find a truly safe (and portable)
mechanism for this concept.</p>
<p>There&#39;s a valid need for thread termination, so at some point
Boost.Threads probably will include it, but only after we can find a
truly safe (and portable) mechanism for this concept.</p>
<h2>9. Is it safe for threads to share automatic storage duration (stack)
objects via pointers or references?</h2>
<h2>9. Is it safe for threads to share automatic storage duration
(stack) objects via pointers or references?</h2>
<p>Only if you can guarantee that the lifetime of the stack object will not end
while other threads might still access the object. Thus the safest practice is
to avoid sharing stack objects, particularly in designs where threads are
created and destroyed dynamically. Restrict sharing of stack objects to simple
designs with very clear and unchanging function and thread lifetimes. (Suggested
by Darryl Green).</p>
<p>Only if you can guarantee that the lifetime of the stack object will
not end while other threads might still access the object. Thus the
safest practice is to avoid sharing stack objects, particularly in
designs where threads are created and destroyed dynamically. Restrict
sharing of stack objects to simple designs with very clear and
unchanging function and thread lifetimes. (Suggested by Darryl
Green).</p>
<hr>
<h2>10. Why has class semaphore disappeared?</h2>
<p>Revised <!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->01 October, 2001<!--webbot bot="Timestamp" endspan i-checksum="38291" -->
</p>
<p>Semaphore was removed as too error prone. The same effect can be
achieved with greater safety by the combination of a mutex and a
condition variable.</p>
<hr>
<p><i>© Copyright <a href="mailto:williamkempf@hotmail.com">William E. Kempf</a>
2001 all rights reserved.</i></p>
<p>Revised
<!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->05 November, 2001<!--webbot bot="Timestamp" endspan i-checksum="39359" --></p>
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<p><i>&copy; Copyright <a href="mailto:williamkempf@hotmail.com">
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<h1 align="center">Boost.Threads</h1>
<h2 align="center">Index</h2>
</td>
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<hr>
<h2>Contents</h2>
<ul>
<li><a href="overview.html">Overview</a></li>
<li>Class <a href="semaphore.html">semaphore</a></li>
<li><a href="mutex_concept.html">Mutex Concepts</a></li>
<ul>
<li><a href="mutex_concept.html#Mutex">Mutex</a></li>
<li><a href="mutex_concept.html#TryMutex">TryMutex</a></li>
<li><a href="mutex_concept.html#TimedMutex">TimedMutex</a></li>
</ul>
<li>Mutex Classes</li>
<ul>
<li><a href="mutex.html">mutex / try_mutex / timed_mutex</a></li>
<li><a href="recursive_mutex.html">recursive_mutex / recursive_try_mutex / recursive_timed_mutex</a></li>
</ul>
<li><a href="lock_concept.html">Lock Concepts</a></li>
<ul>
<li><a href="lock_concept.html#Lock">Lock</a></li>
<li><a href="lock_concept.html#ScopedLock">ScopedLock</a></li>
<li><a href="lock_concept.html#ScopedTryLock">ScopedTryLock</a></li>
<li><a href="lock_concept.html#ScopedTimedLock">ScopedTimedLock</a></li>
</ul>
<li>Lock Classes</li>
<ul>
<li><a href="scoped_lock.html">scoped_lock</a></li>
<li><a href="scoped_try_lock.html">scoped_try_lock</a></li>
<li><a href="scoped_timed_lock.html">scoped_timed_lock</a></li>
</ul>
<li>Class <a href="condition.html">condition</a></li>
<li>Class <a href="thread_specific_ptr.html">thread_specific_ptr</a></li>
<li>Class <a href="thread.html">thread</a></li>
<li>Class <a href="thread_group.html">thread_group</a></li>
<li>Class <a href="xtime.html">xtime</a></li>
<li>Class <a href="lock_error.html">lock_error</a></li>
<li>Class <a href="thread_resource_error.html">thread_resource_error</a></li>
<li>Routine <a href="call_once.html">call_once</a></li>
<li><a href="config.html">Configuration Information</a></li>
<li><a href="introduction.html">Introduction to design</a></li>
<li><a href="rationale.html">Rationale for design decisions</a></li>
<li><a href="definitions.html">Definitions</a></li>
<li><a href="faq.html">Frequently Asked Questions</a></li>
<li><a href="bibliography.html">Bibliography</a></li>
<li><a href="acknowledgements.html">Acknowledgements</a></li>
</ul>
<dl class="index">
<dt><a href="overview.html">Overview</a></dt>
<dt><a href="mutex_concept.html">Mutex Concepts</a></dt>
<dl class="index">
<dt><a href="mutex_concept.html#Mutex">Mutex</a></dt>
<dt><a href="mutex_concept.html#TryMutex">TryMutex</a></dt>
<dt><a href="mutex_concept.html#TimedMutex">TimedMutex</a></dt>
</dl>
<dt><a href="lock_concept.html">Lock Concepts</a></dt>
<dl class="index">
<dt><a href="lock_concept.html#Lock">Lock</a></dt>
<dt><a href="lock_concept.html#ScopedLock">ScopedLock</a></dt>
<dt><a href="lock_concept.html#ScopedTryLock">ScopedTryLock</a></dt>
<dt><a href="lock_concept.html#ScopedTimedLock">ScopedTimedLock</a></dt>
</dl>
<dt>Reference</dt>
<dl class="index">
<dt><a href="mutex.html">&lt;boost/condition.hpp&gt;</a></dt>
<dl class="index">
<dt><a href="header.html#classes">Classes</a></dt>
<dl class="index">
<dt><a href="header.html#mutex">condition</a></dt>
</dl>
</dl>
</dl>
<dl class="index">
<dt><a href="mutex.html">&lt;boost/mutex.hpp&gt;</a></dt>
<dl class="index">
<dt><a href="header.html#classes">Classes</a></dt>
<dl class="index">
<dt><a href="header.html#mutex">mutex</a></dt>
</dl>
<dl class="index">
<dt><a href="header.html#try_mutex">try_mutex</a></dt>
</dl>
<dl class="index">
<dt><a href="header.html#timed_mutex">timed_mutex</a></dt>
</dl>
</dl>
<dt><a href="mutex.html">&lt;boost/recursive_mutex.hpp&gt;</a></dt>
<dl class="index">
<dt><a href="header.html#classes">Classes</a></dt>
<dl class="index">
<dt><a href="header.html#recursive_mutex">recursive_mutex</a></dt>
</dl>
<dl class="index">
<dt><a href="header.html#recursive_try_mutex">recursive_try_mutex</a></dt>
</dl>
<dl class="index">
<dt><a href="header.html#recursive_timed_mutex">recursive_timed_mutex</a></dt>
</dl>
</dl>
</dl>
<dl class="index">
<dt><a href="mutex.html">&lt;boost/tss.hpp&gt;</a></dt>
<dl class="index">
<dt><a href="header.html#classes">Classes</a></dt>
<dl class="index">
<dt><a href="header.html#mutex">thread_specific_ptr</a></dt>
</dl>
</dl>
</dl>
<dl class="index">
<dt><a href="mutex.html">&lt;boost/thread.hpp&gt;</a></dt>
<dl class="index">
<dt><a href="header.html#classes">Classes</a></dt>
<dl class="index">
<dt><a href="header.html#mutex">thread</a></dt>
</dl>
<dl class="index">
<dt><a href="header.html#mutex">thread_group</a></dt>
</dl>
</dl>
</dl>
<dl class="index">
<dt><a href="xtime.html">&lt;boost/xtime.hpp&gt;</a></dt>
<dl class="index">
<dt><a href="header.html#classes">Classes</a></dt>
<dl class="index">
<dt><a href="header.html#mutex">xtime</a></dt>
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<dt><a href="configuration.html">Configuration Information</a></dt>
<dt><a href="introduction.html">Introduction to Design</a></dt>
<dt><a href="rationale.html">Rationale</a></dt>
<dt><a href="definitions.html">Definitions</a></dt>
<dt><a href="faq.html">Frequently Asked Questions (FAQs)</a></dt>
<dt><a href="bibliography.html">Bibliography</a></dt>
<dt><a href="acknowledgments.html">Acknowledgments</a></dt>
</dl>
<hr>
<p>Revised <!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->01 October, 2001<!--webbot bot="Timestamp" endspan i-checksum="38291" -->
<p>Revised
<!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->
05 November, 2001
<!--webbot bot="Timestamp" endspan i-checksum="39359" -->
</p>
<p>©<i> Copyright <a href="mailto:williamkempf@hotmail.com">William E. Kempf</a>
2001</i></p>
<p>Permission to use, copy, modify, distribute and sell this software
and its documentation for any purpose is hereby granted without fee,
provided that the above copyright notice appear in all copies and
that both that copyright notice and this permission notice appear
in supporting documentation. William E. Kempf makes no representations
about the suitability of this software for any purpose.
It is provided &quot;as is&quot; without express or implied warranty.</p>
<p><i>&copy; Copyright <a href="mailto:wekempf@cox.net">William E. Kempf</a> 2001-2002.
All Rights Reserved.</i></p>
<p>Permission to use, copy, modify, distribute and sell this software and its
documentation for any purpose is hereby granted without fee, provided that the
above copyright notice appear in all copies and that both that copyright notice
and this permission notice appear in supporting documentation. William E. Kempf
makes no representations about the suitability of this software for any purpose.
It is provided &quot;as is&quot; without express or implied warranty.</p>
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<title>Boost.Threads, Introduction</title>
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<title>Boost.Threads - Overview</title>
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<h2 align="center">Introduction</h2>
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<h1 align="center">Boost.Threads</h1>
<h2 align="center">Introduction to Design</h2>
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<hr>
<h3>Motivation</h3>
<p>With client/server and three-tier architectures becoming common place in today's
world, it's becoming increasingly important for programs to be able to handle parallel
processing. Modern day operating systems usually provide some support for this
through native thread APIs. Unfortunately, writing portable code that makes use
of parallel processing in C++ is made very difficult by a lack of a standard interface
for these native APIs. Further, these APIs are almost universally C APIs and fail to
take advantage of C++'s strengths, or to address C++'s issues.</p>
<p>The <b>Boost.Threads</b> library is an attempt to define a portable interface for writing
parallel processes in C++.</p>
<h3>Goals</h3>
<p>The <b>Boost.Threads</b> library has several goals that should help to set it apart from
other solutions. These goals are listed in order of precedence with full descriptions
below.<p>
<dl class="page-index">
<dt><a href="#motivation">Motivation</a></dt>
<dt><a href="#goals">Goals</a></dt>
<dt><a href="#phases">Iterative Phases</a></dt>
<dl class="page-index">
<dt><a href="#phase1">Phase 1, Synchronization Primitives</a></dt>
<dt><a href="#phase2">Phase 2, Thread Management and Thread Specific Storage</a></dt>
<dt><a href="#next-phase">The Next Phase</a></dt>
</dl>
</dl>
<h2><a name="motivation"></a>Motivation</h2>
<p>With client/server and three-tier architectures becoming common place in today&#39;s
world, it&#39;s becoming increasingly important for programs to be able to handle
parallel processing. Modern day operating systems usually provide some support
for this through native thread APIs. Unfortunately, writing portable code that
makes use of parallel processing in C++ is made very difficult by a lack of
a standard interface for these native APIs. Further, these APIs are almost universally
C APIs and fail to take advantage of C++&#39;s strengths, or to address C++&#39;s
issues.</p>
<p>The <b>Boost.Threads</b> library is an attempt to define a portable interface
for writing parallel processes in C++.</p>
<h2><a name="goals"></a>Goals</h2>
<p>The <b>Boost.Threads</b> library has several goals that should help to set
it apart from other solutions. These goals are listed in order of precedence
with full descriptions below.</p>
<ul>
<li><b>Portability</b>
<p><b>Boost.Threads</b> was designed to be highly portable. The goal is for the
interface to be easily implemented on any platform that supports threads,
and possibly even on platforms without native thread support.</p>
<li><b>Safety</b>
<p><b>Boost.Threads</b> was designed to be as safe as possible. Writing
<a href="definitions.html#Thread-safe">thread-safe</a>
code is very difficult and successful libraries must strive to insulate
the programmer from dangerous constructs as much as possible. This is accomplished
in several ways:</p>
<ul>
<li><p align="left">C++ language features are used make correct usage easy (if possible,
the default) and error-prone impossible or at least more difficult.
For example, see the <a href="mutex_concept.html">Mutex</a> and <a href="lock_concept.html">Lock</a>
designs, and how note how they interact.</p></li>
<li>
<p align="left">Certain traditional concurrent programming features
are considered so error-prone that they are not provided at all. For
example, see the <a href="rationale.html#Events">Events Not Provided</a>
rationale.</p>
</li>
<li>
<p align="left">Dangerous features, or features which may be misused,
are identified as such in the documentation to make users aware of
potential pitfalls. For example, see <a href="semaphore.html#Danger">Semaphore</a>.</p>
</li>
</ul>
<li><b>Flexibility</b>
<p><b>Boost.Threads</b> was designed to be flexible. This goal is often at odds
with <i>safety</i>. When functionality might be compromised by the desire
to keep the interface safe, <b>Boost.Threads</b> has been designed to provide
the functionality, but to make it's use prohibitive for general use.</p>
<li><b>Efficiency</b>
<p><b>Boost.Threads</b> was designed to be as efficient as possible. When building
a library on top of another library there is always a danger that the result
will be so much slower than the "native" API that programmers are inclined
to ignore the higher level API. <b>Boost.Threads</b> was designed to minimize the
chances of this occurring. The interfaces have been crafted to allow an
implementation the greatest chance of being as efficient as possible. This
goal is often at odds with the goal for <i>safety</i>. Every effort was made to
ensure efficient implementations, but when in conflict <i>safety</i> has always taken
precedence.</p>
</li>
<li> <b>Portability</b>
<p><b>Boost.Threads</b> was designed to be highly portable. The goal is for
the interface to be easily implemented on any platform that supports threads,
and possibly even on platforms without native thread support.</p>
</li>
<li> <b>Safety</b>
<p><b>Boost.Threads</b> was designed to be as safe as possible. Writing <a href="definitions.html#Thread-safe">thread-safe</a>
code is very difficult and successful libraries must strive to insulate
the programmer from dangerous constructs as much as possible. This is accomplished
in several ways:</p>
<ul>
<li>
<p align="left">C++ language features are used make correct usage easy
(if possible, the default) and error-prone impossible or at least more
difficult. For example, see the <a href="mutex_concept.html">Mutex</a>
and <a href="lock_concept.html">Lock</a> designs, and how note how they
interact.</p>
</li>
<li>
<p align="left">Certain traditional concurrent programming features are
considered so error-prone that they are not provided at all. For example,
see the <a
href="rationale.html#Events">Events Not Provided</a> rationale.</p>
</li>
<li>
<p align="left">Dangerous features, or features which may be misused,
are identified as such in the documentation to make users aware of potential
pitfalls.</p>
</li>
</ul>
</li>
<li> <b>Flexibility</b>
<p><b>Boost.Threads</b> was designed to be flexible. This goal is often at
odds with <i>safety</i>. When functionality might be compromised by the
desire to keep the interface safe, <b> Boost.Threads</b> has been designed
to provide the functionality, but to make it&#39;s use prohibitive for general
use.</p>
</li>
<li> <b>Efficiency</b>
<p><b>Boost.Threads</b> was designed to be as efficient as possible. When
building a library on top of another library there is always a danger that
the result will be so much slower than the &quot;native&quot; API that programmers
are inclined to ignore the higher level API. <b>Boost.Threads</b> was designed
to minimize the chances of this occurring. The interfaces have been crafted
to allow an implementation the greatest chance of being as efficient as
possible. This goal is often at odds with the goal for <i>safety</i>. Every
effort was made to ensure efficient implementations, but when in conflict
<i>safety</i> has always taken precedence.</p>
</li>
</ul>
<h3>Iterative Phases</h3>
<p>Another goal of <b>Boost.Threads</b> was to take a dynamic, iterative
approach in its development. The computing industry is still exploring the concepts of parallel programming.
Most thread libraries supply only simple primitive concepts for thread synchronization.
These concepts are very simple, but they are very difficult to use safely or to provide
formal proofs for constructs built on top of them. Until recently, these primitives
were "state of the art" and the only concepts available to programmers. Recently
there has been a lot of research in other concepts, such as in "Communicating Sequential
Processes." <b>Boost.Threads</b> was designed in iterative steps, providing the building
blocks necessary for the next step, and giving the researcher the tools necessary to
explore new concepts in a portable manner.</p>
<p>Given the goal of following a dynamic, iterative approach <b>Boost.Threads</b> shall go through
several growth cycles. Each phase in its development shall be roughly documented here.</p>
<h4>Phase 1, Synchronization Primitives</h4>
<p>Boost is all about providing high quality libraries with implementations for many platforms.
Unfortunately, there's a big problem faced by developers wishing to supply such high quality
libraries, namely thread-safety. The C++ standard doesn't address threads at all, but real
world programs often make use of native threading support. A portable library that doesn't
address the issue of thread-safety is there for not much help to a programmer who wants to
use the library in his multi-threaded application. So there's a very great need for portable
primitives that will allow the library developer to create <a href="definitions.html#Thread-safe">thread-safe</a>
implementations. This
need far out weighs the need for portable methods to create and manage threads.</p>
<p>Because of this need, the first phase of <b>Boost.Threads</b> focuses solely on providing
portable primitive concepts for thread synchronization. Types provided in this phase include
the <A href="semaphore.html">semaphore</a>, <A href="mutex.html">mutex/try_mutex/timed_mutex</a>,
<A href="recursive_mutex.html">recursive_mutex/recursive_try_mutex/recursive_timed_mutex</a>,
<A href="scoped_lock.html">scoped_lock</a>, <A href="scoped_try_lock.html">scoped_try_lock</a>,
<A href="scoped_timed_lock.html">scoped_timed_lock</a> and <A href="lock_error.html">lock_error</a>.
These are considered the "core" synchronization primitives, though there are others that will
be added in later phases.</p>
<h4>Phase 2, Thread Management and Thread Specific Storage</h4>
<p>This phase addresses the creation and management of threads and provides a mechanism for
thread specific storage (data associated with a thread instance). Thread management is a tricky
issue in C++, so this phase addresses only the basic needs of multi-threaded program. Later
phases are likely to add additional functionality in this area. This phase of <b>Boost.Threads</b>
adds the <A href="thread.html">thread</a> and
<A href="thread_specific_ptr.html">thread_specific_ptr</a> types. With these additions
the <b>Boost.Threads</b> library can be considered minimal but complete.</p>
<h4>The Next Phase</h4>
<p>The next phase will address more advanced synchronization concepts, such as read/write mutexes
and barriers.</p>
<h2><a name="phases"></a>Iterative Phases</h2>
<p>Another goal of <b>Boost.Threads</b> was to take a dynamic, iterative approach
in its development. The computing industry is still exploring the concepts of
parallel programming. Most thread libraries supply only simple primitive concepts
for thread synchronization. These concepts are very simple, but they are very
difficult to use safely or to provide formal proofs for constructs built on
top of them. Until recently, these primitives were &quot;state of the art&quot;
and the only concepts available to programmers. Recently there has been a lot
of research in other concepts, such as in &quot;Communicating Sequential Processes.&quot;
<b>Boost.Threads</b> was designed in iterative steps, providing the building
blocks necessary for the next step, and giving the researcher the tools necessary
to explore new concepts in a portable manner.</p>
<p>Given the goal of following a dynamic, iterative approach <b> Boost.Threads</b>
shall go through several growth cycles. Each phase in its development shall
be roughly documented here.</p>
<h3><a name="phase1"></a>Phase 1, Synchronization Primitives</h3>
<p>Boost is all about providing high quality libraries with implementations for
many platforms. Unfortunately, there&#39;s a big problem faced by developers
wishing to supply such high quality libraries, namely thread-safety. The C++
standard doesn&#39;t address threads at all, but real world programs often make
use of native threading support. A portable library that doesn&#39;t address
the issue of thread-safety is there for not much help to a programmer who wants
to use the library in his multi-threaded application. So there&#39;s a very
great need for portable primitives that will allow the library developer to
create <a href="definitions.html#Thread-safe"> thread-safe</a> implementations.
This need far out weighs the need for portable methods to create and manage
threads.</p>
<p>Because of this need, the first phase of <b>Boost.Threads</b> focuses solely
on providing portable primitive concepts for thread synchronization. Types provided
in this phase include the <a href="mutex.html"> mutex/try_mutex/timed_mutex</a>,
<a href="recursive_mutex.html"> recursive_mutex/recursive_try_mutex/recursive_timed_mutex</a>,
<a href=
"scoped_lock.html">scoped_lock</a>, <a href="scoped_try_lock.html"> scoped_try_lock</a>,
<a href="scoped_timed_lock.html"> scoped_timed_lock</a> and <a href="lock_error.html">lock_error</a>.
These are considered the &quot;core&quot; synchronization primitives, though
there are others that will be added in later phases.</p>
<h3><a name="phase2"></a>Phase 2, Thread Management and Thread Specific Storage</h3>
<p>This phase addresses the creation and management of threads and provides a
mechanism for thread specific storage (data associated with a thread instance).
Thread management is a tricky issue in C++, so this phase addresses only the
basic needs of multi-threaded program. Later phases are likely to add additional
functionality in this area. This phase of <b>Boost.Threads</b> adds the <a href="thread.html">thread</a>
and <a href="thread_specific_ptr.html">thread_specific_ptr</a> types. With these
additions the <b>Boost.Threads</b> library can be considered minimal but complete.</p>
<h3><a name="next-phase"></a>The Next Phase</h3>
<p>The next phase will address more advanced synchronization concepts, such as
read/write mutexes and barriers.</p>
<hr>
<p>Revised <!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->01 October, 2001<!--webbot bot="Timestamp" endspan i-checksum="38291" -->
<hr>
<p>Revised
<!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->
05 November, 2001
<!--webbot bot="Timestamp" endspan i-checksum="39359" -->
</p>
<p><i>© Copyright <A href="mailto:williamkempf@hotmail.com">William E. Kempf</a>
2001 all rights reserved.</i></p>
<p><i>&copy; Copyright <a href="mailto:wekempf@cox.net">William E. Kempf</a> 2001-2002.
All Rights Reserved.</i></p>
<p>Permission to use, copy, modify, distribute and sell this software and its
documentation for any purpose is hereby granted without fee, provided that the
above copyright notice appear in all copies and that both that copyright notice
and this permission notice appear in supporting documentation. William E. Kempf
makes no representations about the suitability of this software for any purpose.
It is provided &quot;as is&quot; without express or implied warranty.</p>
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<tr>
<td valign="top" width="300">
<h3><img src="../../../c++boost.gif" alt="C++ Boost" width="277" height="86"></h3>
</td>
<td valign="top">
<h1 align="center">Boost.Threads</h1>
<h2 align="center">Lock Concepts</h2>
</td>
</tr>
</table>
<td valign="top">
<h1 align="center">Boost.Threads</h1>
<hr>
<h2 align="center">Lock Concepts</h2>
</td>
</tr>
</table>
<hr>
<p><a href="#Introduction">Introduction</a><br>
<a href="#Requirements">Concept Requirements</a><br>
<a href="#Lock">Lock Concept</a><br>
<a href="#ScopedLock">ScopedLock Concept</a><br>
<a href="#ScopedTryLock">ScopedTryLock Concept</a><br>
<a href="#ScopedTimedLock">ScopedTimedLock Concept</a><br>
<a href="#Models">Models</a></p>
<p><a href="#Introduction">Introduction</a><br>
<a href="#Requirements">Concept Requirements</a><br>
<a href="#Lock">Lock Concept</a><br>
<a href="#ScopedLock">ScopedLock Concept</a><br>
<a href="#ScopedTryLock">ScopedTryLock Concept</a><br>
<a href="#ScopedTimedLock">ScopedTimedLock Concept</a><br>
<a href="#Models">Models</a></p>
<h2><a name="Introduction">Introduction</a></h2>
<h2><a name="Introduction">Introduction</a></h2>
<p>The lock concepts provide exception safe means for locking and unlocking a
<a href="mutex_concept.html">mutex model</a>. In other words they are an
implementation of the <i>Scoped Locking</i>
<a href="bibliography.html#Schmidt 00">[Schmidt 00]</a> pattern. The
<a href="#ScopedLock">ScopedLock</a> concept, with
<a href="#ScopedTryLock">ScopedTryLock</a> and
<a href="#ScopedTimedLock">ScopedTimedLock</a> refinements, formalize the
requirements.</p>
<p>The lock concepts provide exception safe means for locking and
unlocking a <a href="mutex_concept.html">mutex model</a>. In other
words they are an implementation of the <i>Scoped Locking</i> <a href=
"bibliography.html#Schmidt 00">[Schmidt 00]</a> pattern. The <a href=
"#ScopedLock">ScopedLock</a> concept, with <a href="#ScopedTryLock">
ScopedTryLock</a> and <a href="#ScopedTimedLock">ScopedTimedLock</a>
refinements, formalize the requirements.</p>
<p>Lock models are constructed with a reference to a
<a href="mutex_concept.html">mutex model</a> and typically acquire ownership of the
<a href="mutex_concept.html">mutex model</a> by setting its state to locked. They also
ensure ownership is relinquished in the destructor. Lock models also expose functions
to query the lock status and to manually lock and unlock the
<a href="mutex_concept.html">mutex model</a>.</p>
<p>Lock models are constructed with a reference to a <a href=
"mutex_concept.html">mutex model</a> and typically acquire ownership of
the <a href="mutex_concept.html">mutex model</a> by setting its state
to locked. They also ensure ownership is relinquished in the
destructor. Lock models also expose functions to query the lock status
and to manually lock and unlock the <a href="mutex_concept.html">mutex
model</a>.</p>
<p>Instances of lock models are meant to be short lived, expected to be used at block
scope only. The lock models are not
<a href="definitions.html#Thread-safe">thread-safe</a>. Lock models must maintain state
to indicate whether or not they've been locked and this state is not protected by any
synchronization concepts. For this reason an instance of a lock model should never be
shared between multiple threads.</p>
<p>Instances of lock models are meant to be short lived, expected to be
used at block scope only. The lock models are not <a href=
"definitions.html#Thread-safe">thread-safe</a>. Lock models must
maintain state to indicate whether or not they&#39;ve been locked and
this state is not protected by any synchronization concepts. For this
reason an instance of a lock model should never be shared between
multiple threads.</p>
<h2>Concept <a name="Requirements">Requirements</a></h2>
<h2>Concept <a name="Requirements">Requirements</a></h2>
<p>[For documentation purposes, portions of the concept requirements are
repeated in the documentation for specific lock classes. Those copies need
to be kept in sync with the requirements here.]</p>
<p>[For documentation purposes, portions of the concept requirements
are repeated in the documentation for specific lock classes. Those
copies need to be kept in sync with the requirements here.]</p>
<h3><a name="Lock">Lock</a> Concept</h3>
<h3><a name="Lock">Lock</a> Concept</h3>
<p>For a <a href="#ScopedLock"> ScopedLock</a>,
<a href="#ScopedTryLock">ScopedTryLock</a>, or
<a href="#ScopedTimedLock">ScopedTimedLock</a> type <code>L</code> and an object
<code>lk</code> and const object <code>clk</code> of that type, the following expressions
must be well-formed and have the indicated effects.</p>
<p>For a <a href="#ScopedLock">ScopedLock</a>, <a href=
"#ScopedTryLock">ScopedTryLock</a>, or <a href="#ScopedTimedLock">
ScopedTimedLock</a> type <code>L</code> and an object <code>lk</code>
and const object <code>clk</code> of that type, the following
expressions must be well-formed and have the indicated effects.</p>
<p>The Lock concept is used as a base for the <a href="#ScopedLock">ScopedLock</a>,
<a href="#ScopedTryLock">ScopedTryLock</a>, and
<a href="#ScopedTimedLock">ScopedTimedLock</a> refinements. The associated mutex type
is as specified for each of those refinements respectively.</p>
<p>The Lock concept is used as a base for the <a href="#ScopedLock">
ScopedLock</a>, <a href="#ScopedTryLock">ScopedTryLock</a>, and <a
href="#ScopedTimedLock">ScopedTimedLock</a> refinements. The associated
mutex type is as specified for each of those refinements
respectively.</p>
<table border="1" cellpadding="5">
<tr>
<td><b>Expression</b></td>
<td><b>Effects</b></td>
</tr>
<tr>
<td valign="top"><code>(&amp;lk)-&gt;~L();</code></td>
<td><code>if (locked()) unlock();</code></td>
</tr>
<tr>
<td valign="top"><code>(&amp;clk)-&gt;operator const void*()</code></td>
<td>Returns type void*, non-zero if if the associated mutex has been locked
by <code>clk</code>, otherwise 0.</td>
</tr>
<tr>
<td valign="top"><code>clk.locked()</code></td>
<td>Returns a <code>bool</code>, <code>(&amp;clk)-&gt;operator const void*() != 0</code></td>
</tr>
<tr>
<td valign="top"><code>lk.lock()</code></td>
<td>Throws lock_error if locked(). If the associated mutex is already locked by some other
thread, places the current thread in the
<a href="definitions.html#State">Blocked</a> state until the associated mutex is
unlocked, after which the current thread is placed in the
<a href="definitions.html#State">Ready</a> state, eventually to be returned to the
<a href="definitions.html#State">Running</a> state.<br>
Postcondition: locked()</td>
</tr>
<tr>
<td valign="top"><code>lk.unlock()</code></td>
<td>If !locked(), throws lock_error, otherwise unlocks the associated mutex.<br>
Postcondition: !locked()</td>
</tr>
</table>
<table summary="Lock expressions" border="1" cellpadding="5">
<tr>
<td><b>Expression</b></td>
<h3><a name="ScopedLock">ScopedLock</a> Concept</h3>
<td><b>Effects</b></td>
</tr>
<p>A ScopedLock must meet the <a href="#Lock">Lock</a> requirements. For a ScopedLock
type <code>L</code> and an object <code>lk</code> of that type,
and an object <code>m</code> of a type meeting the
<a href="mutex_concept.html#Mutex">Mutex</a> requirements, and an object <code>b</code>
of type <code>bool</code>, the following expressions must be well-formed and have the
indicated effects.</p>
<tr>
<td valign="top"><code>(&amp;lk)-&gt;~L();</code></td>
<table border="1" cellpadding="5">
<tr>
<td><b>Expression</b></td>
<td><b>Effects</b></td>
</tr>
<tr>
<td valign="top"><code>L lk(m);</code></td>
<td>Constructs an object <code>lk</code>, and associates mutex <code>m</code> with
it, then calls <code>lock()</code></td>
</tr>
<tr>
<td valign="top"><code>L lk(m,b);</code></td>
<td>Constructs an object <code>lk</code>, and associates mutex <code>m</code> with
it, then if <code>b</code>, calls <code>lock()</code></td>
</tr>
</table>
<td><code>if (locked()) unlock();</code></td>
</tr>
<h3><a name="ScopedTryLock">ScopedTryLock</a> Concept</h3>
<tr>
<td valign="top"><code>(&amp;clk)-&gt;operator const
void*()</code></td>
<p>A ScopedTryLock must meet the <a href="#Lock">Lock</a> requirements. For a
ScopedTryLock type <code>L</code> and an object <code>lk</code> of that type,
and an object <code>m</code> of a type meeting the
<a href="mutex_concept.html#TryMutex">TryMutex</a> requirements, and an object
<code>b</code> of type <code>bool</code>, the following expressions must be well-formed
and have the indicated effects.</p>
<td>Returns type void*, non-zero if if the associated mutex has
been locked by <code>clk</code>, otherwise 0.</td>
</tr>
<table border="1" cellpadding="5">
<tr>
<td><b>Expression</b></td>
<td><b>Effects</b></td>
</tr>
<tr>
<td valign="top"><code>L lk(m);</code></td>
<td>Constructs an object <code>lk</code>, and associates mutex <code>m</code> with
it, then calls <code>try_lock()</code></td>
</tr>
<tr>
<td valign="top"><code>L lk(m,b);</code></td>
<td>Constructs an object <code>lk</code>, and associates mutex <code>m</code> with
it, then if <code>b</code>, calls <code>lock()</code></td>
</tr>
<tr>
<td valign="top"><code>lk.try_lock()</code></td>
<td>If locked(), throws <code>lock_error</code>. Makes a non-blocking attempt to
lock the associated mutex, returning <code>true</code> if the lock attempt is
successful, otherwise <code>false</code>.</td>
</tr>
</table>
<tr>
<td valign="top"><code>clk.locked()</code></td>
<h3><a name="ScopedTimedLock">ScopedTimedLock</a> Concept</h3>
<td>Returns a <code>bool</code>, <code>(&amp;clk)-&gt;operator
const void*() != 0</code></td>
</tr>
<p>A ScopedTimedLock must meet the <a href="#Lock">Lock</a> requirements. For a
ScopedTimedLock type <code>L</code> and an object <code>lk</code> of that type,
and an object <code>m</code> of a type meeting the
<a href="mutex_concept.html#TimedMutex">TimedMutex</a> requirements, and an object
<code>b</code> of type <code>bool</code>, and an object <code>t</code> of type
<code><a href="xtime.html">xtime</a></code>, the following expressions must be well-formed and have the indicated
effects.</p>
<tr>
<td valign="top"><code>lk.lock()</code></td>
<table border="1" cellpadding="5">
<tr>
<td><b>Expression</b></td>
<td><b>Effects</b></td>
</tr>
<tr>
<td valign="top"><code>L lk(m,t);</code></td>
<td>Constructs an object <code>lk</code>, and associates mutex <code>m</code> with
it, then calls <code>timed_lock(t)</code></td>
</tr>
<tr>
<td valign="top"><code>L lk(m,b);</code></td>
<td>Constructs an object <code>lk</code>, and associates mutex <code>m</code> with
it, then if <code>b</code>, calls <code>lock()</code></td>
</tr>
<tr>
<td valign="top"><code>lk.timed_lock(t)</code></td>
<td>If locked(), throws lock_error. Makes a blocking attempt to lock the
associated mutex, and returns <code>true</code> if successful within the specified
time <code>t</code>, otherwise <code>false</code>.</td>
</tr>
</table>
<td>Throws lock_error if locked(). If the associated mutex is
already locked by some other thread, places the current thread
in the <a href="definitions.html#State">Blocked</a> state until
the associated mutex is unlocked, after which the current
thread is placed in the <a href="definitions.html#State">
Ready</a> state, eventually to be returned to the <a href=
"definitions.html#State">Running</a> state.<br>
Postcondition: locked()</td>
</tr>
<h2><a name="Models">Models</a></h2>
<tr>
<td valign="top"><code>lk.unlock()</code></td>
<p><b>Boost.Threads</b> currently supplies three classes which model lock concepts.</p>
<td>If !locked(), throws lock_error, otherwise unlocks the
associated mutex.<br>
Postcondition: !locked()</td>
</tr>
</table>
<p>These classes are normally accessed via typedefs of the same name supplied by
a <a href="mutex_concept.html">mutex model</a>.</p>
<h3><a name="ScopedLock">ScopedLock</a> Concept</h3>
<table border="1" cellpadding="5">
<tr>
<td><b>Concept</b></td>
<td><b>Refines</b></td>
<td><b>Classes Modeling the Concept</b></td>
</tr>
<tr>
<td><a href="#ScopedLock">ScopedLock</a></td>
<td>&nbsp;</td>
<td><a href="scoped_lock.html">scoped_lock</a></td>
</tr>
<tr>
<td><a href="#ScopedTryLock">ScopedTryLock</a></td>
<td><a href="#ScopedLock">ScopedLock</a></td>
<td><a href="scoped_try_lock.html">scoped_try_lock</a> </td>
</tr>
<tr>
<td><a href="#ScopedTimedLock">ScopedTimedLock</a></td>
<td><a href="#ScopedLock">ScopedLock</a></td>
<td><a href="scoped_timed_lock.html">scoped_timed_lock</a></td>
</tr>
</table>
<p>A ScopedLock must meet the <a href="#Lock">Lock</a> requirements.
For a ScopedLock type <code>L</code> and an object <code>lk</code> of
that type, and an object <code>m</code> of a type meeting the <a href=
"mutex_concept.html#Mutex">Mutex</a> requirements, and an object <code>
b</code> of type <code>bool</code>, the following expressions must be
well-formed and have the indicated effects.</p>
<hr>
<table summary="ScopedLock expressions" border="1" cellpadding="5">
<tr>
<td><b>Expression</b></td>
<p>Revised <!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->01 October, 2001<!--webbot bot="Timestamp" endspan i-checksum="38291" -->
</p>
<td><b>Effects</b></td>
</tr>
<p><i>© Copyright <a href="mailto:williamkempf@hotmail.com">William E. Kempf</a>
2001 all rights reserved.</i></p>
<tr>
<td valign="top"><code>L lk(m);</code></td>
</body>
<td>Constructs an object <code>lk</code>, and associates mutex
<code>m</code> with it, then calls <code>lock()</code></td>
</tr>
<tr>
<td valign="top"><code>L lk(m,b);</code></td>
<td>Constructs an object <code>lk</code>, and associates mutex
<code>m</code> with it, then if <code>b</code>, calls <code>
lock()</code></td>
</tr>
</table>
<h3><a name="ScopedTryLock">ScopedTryLock</a> Concept</h3>
<p>A ScopedTryLock must meet the <a href="#Lock">Lock</a> requirements.
For a ScopedTryLock type <code>L</code> and an object <code>lk</code>
of that type, and an object <code>m</code> of a type meeting the <a
href="mutex_concept.html#TryMutex">TryMutex</a> requirements, and an
object <code>b</code> of type <code>bool</code>, the following
expressions must be well-formed and have the indicated effects.</p>
<table summary="ScopedTryLock expressions" border="1" cellpadding="5">
<tr>
<td><b>Expression</b></td>
<td><b>Effects</b></td>
</tr>
<tr>
<td valign="top"><code>L lk(m);</code></td>
<td>Constructs an object <code>lk</code>, and associates mutex
<code>m</code> with it, then calls <code>try_lock()</code></td>
</tr>
<tr>
<td valign="top"><code>L lk(m,b);</code></td>
<td>Constructs an object <code>lk</code>, and associates mutex
<code>m</code> with it, then if <code>b</code>, calls <code>
lock()</code></td>
</tr>
<tr>
<td valign="top"><code>lk.try_lock()</code></td>
<td>If locked(), throws <code>lock_error</code>. Makes a
non-blocking attempt to lock the associated mutex, returning
<code>true</code> if the lock attempt is successful, otherwise
<code>false</code>.</td>
</tr>
</table>
<h3><a name="ScopedTimedLock">ScopedTimedLock</a> Concept</h3>
<p>A ScopedTimedLock must meet the <a href="#Lock">Lock</a>
requirements. For a ScopedTimedLock type <code>L</code> and an object
<code>lk</code> of that type, and an object <code>m</code> of a type
meeting the <a href="mutex_concept.html#TimedMutex">TimedMutex</a>
requirements, and an object <code>b</code> of type <code>bool</code>,
and an object <code>t</code> of type <code><a href="xtime.html">
xtime</a></code>, the following expressions must be well-formed and
have the indicated effects.</p>
<table summary="ScopedTimedLock expressions" border="1" cellpadding=
"5">
<tr>
<td><b>Expression</b></td>
<td><b>Effects</b></td>
</tr>
<tr>
<td valign="top"><code>L lk(m,t);</code></td>
<td>Constructs an object <code>lk</code>, and associates mutex
<code>m</code> with it, then calls <code>
timed_lock(t)</code></td>
</tr>
<tr>
<td valign="top"><code>L lk(m,b);</code></td>
<td>Constructs an object <code>lk</code>, and associates mutex
<code>m</code> with it, then if <code>b</code>, calls <code>
lock()</code></td>
</tr>
<tr>
<td valign="top"><code>lk.timed_lock(t)</code></td>
<td>If locked(), throws lock_error. Makes a blocking attempt to
lock the associated mutex, and returns <code>true</code> if
successful within the specified time <code>t</code>, otherwise
<code>false</code>.</td>
</tr>
</table>
<h2><a name="Models">Models</a></h2>
<p><b>Boost.Threads</b> currently supplies three classes which model
lock concepts.</p>
<p>These classes are normally accessed via typedefs of the same name
supplied by a <a href="mutex_concept.html">mutex model</a>.</p>
<table summary="Lock concept classes" border="1" cellpadding="5">
<tr>
<td><b>Concept</b></td>
<td><b>Refines</b></td>
<td><b>Classes Modeling the Concept</b></td>
</tr>
<tr>
<td><a href="#ScopedLock">ScopedLock</a></td>
<td>&nbsp;</td>
<td><a href="scoped_lock.html">scoped_lock</a></td>
</tr>
<tr>
<td><a href="#ScopedTryLock">ScopedTryLock</a></td>
<td><a href="#ScopedLock">ScopedLock</a></td>
<td><a href="scoped_try_lock.html">scoped_try_lock</a> </td>
</tr>
<tr>
<td><a href="#ScopedTimedLock">ScopedTimedLock</a></td>
<td><a href="#ScopedLock">ScopedLock</a></td>
<td><a href="scoped_timed_lock.html">scoped_timed_lock</a></td>
</tr>
</table>
<hr>
<p>Revised
<!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->05 November, 2001<!--webbot bot="Timestamp" endspan i-checksum="39359" --></p>
<p><i>&copy; Copyright <a href="mailto:williamkempf@hotmail.com">
William E. Kempf</a> 2001 all rights reserved.</i></p>
</body>
</html>

View File

@@ -1,49 +1,52 @@
<html>
<head>
<meta http-equiv="Content-Type" content=
"text/html; charset=iso-8859-1">
<meta name="keywords" content="threads, BTL, thread library, C++">
<link rel="stylesheet" type="text/css" href="styles.css">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<meta name="keywords" content="threads, BTL, thread library, C++">
<link rel="stylesheet" type="text/css" href="styles.css">
<title>Boost.Threads, lock_error</title>
</head>
<title>Boost.Threads, lock_error</title>
</head>
<body bgcolor="#FFFFFF" link="#0000FF" vlink="#800080">
<body bgcolor="#FFFFFF" link="#0000FF" vlink="#800080">
<table summary="header" border="0" cellpadding="7" cellspacing="0"
width="100%">
<tr>
<td valign="top" width="300">
<h3><img src="../../../c++boost.gif" alt="C++ Boost" width=
"277" height="86"></h3>
</td>
<table border="0" cellpadding="7" cellspacing="0" width="100%">
<tr>
<td valign="top" width="300">
<h3><img src="../../../c++boost.gif" alt="C++ Boost" width="277" height="86"></h3>
</td>
<td valign="top">
<h1 align="center">Boost.Threads</h1>
<h2 align="center">lock_error</h2>
</td>
</tr>
</table>
<td valign="top">
<h1 align="center">Boost.Threads</h1>
<hr>
<h2 align="center">lock_error</h2>
</td>
</tr>
</table>
<hr>
<p><a href="#Introduction">Introduction</a><br>
<a href="#Header">Header</a><br>
<a href="#Synopsis">Synopsis</a><br>
<a href="#Members">Members</a><br>
<a href="#Example">Example</a></p>
<p><a href="#Introduction">Introduction</a><br>
<a href="#Header">Header</a><br>
<a href="#Synopsis">Synopsis</a><br>
<a href="#Members">Members</a><br>
<a href="#Example">Example</a></p>
<h2><a name="Introduction">Introduction</a></h2>
<h2><a name="Introduction">Introduction</a></h2>
<p>The <tt>lock_error</tt> class defines an exception type thrown to indicate a
locking related error has been detected. Examples of such errors include a lock
operation which can be determined to result in a deadlock, or unlock operations
attempted by a thread that does not own the lock.</p>
<h2><a name="Header">Header</a></h2>
<p>The <tt>lock_error</tt> class defines an exception type thrown to
indicate a locking related error has been detected. Examples of such
errors include a lock operation which can be determined to result in a
deadlock, or unlock operations attempted by a thread that does not own
the lock.</p>
<h2><a name="Header">Header</a></h2>
<pre>
#include <a href="../../../boost/thread/thread.hpp">&lt;boost/thread/thread.hpp&gt;</a>
#include <a href=
"../../../boost/thread/thread.hpp">&lt;boost/thread/thread.hpp&gt;</a>
</pre>
<h2><a name="Synopsis">Synopsis</a></h2>
<h2><a name="Synopsis">Synopsis</a></h2>
<pre>
namespace boost
@@ -55,25 +58,23 @@ namespace boost
}
</pre>
<h2><a name="Members">Members</a></h2>
<hr>
<h3>Constructor</h3>
<h2><a name="Members">Members</a></h2>
<hr>
<h3>Constructor</h3>
<pre>
lock_error();
</pre>
<p>Constructs a <tt>lock_error</tt> object.</p>
<hr>
<h2><a name="Example">Example</a> Usage</h2>
<p>Constructs a <tt>lock_error</tt> object.</p>
<hr>
<h2><a name="Example">Example</a> Usage</h2>
<pre>
#include <a href="../../../boost/thread/mutex.hpp">&lt;boost/thread/mutex.hpp&gt;</a>
#include <a href="../../../boost/thread/thread.hpp">&lt;boost/thread/thread.hpp&gt;</a>
#include <a href=
"../../../boost/thread/mutex.hpp">&lt;boost/thread/mutex.hpp&gt;</a>
#include <a href=
"../../../boost/thread/thread.hpp">&lt;boost/thread/thread.hpp&gt;</a>
#include &lt;iostream&gt;
int main(int, char*[])
@@ -93,19 +94,17 @@ int main(int, char*[])
}
</pre>
<p>The output is:</p>
<p>The output is:</p>
<pre>
thread lock error - deadlock occurred.
</pre>
<hr>
<hr>
<p>Revised
<!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->05 November, 2001<!--webbot bot="Timestamp" endspan i-checksum="39359" --></p>
<p>Revised <!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->01 October, 2001<!--webbot bot="Timestamp" endspan i-checksum="38291" -->
</p>
<p><i>© Copyright <a href="mailto:williamkempf@hotmail.com">William E. Kempf</a>
2001 all rights reserved.</i></p>
</body>
<p><i>&copy; Copyright <a href="mailto:williamkempf@hotmail.com">
William E. Kempf</a> 2001 all rights reserved.</i></p>
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<title>Boost.Threads, mutex</title>
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<title>Boost.Threads, mutex</title>
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<h3><img alt="C++ Boost" src="../../../c++boost.gif" width=
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<h3><IMG alt="C++ Boost" src="../../../c++boost.gif" width="277" height="86"></h3>
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<td valign="top">
<h1 align="center">Boost.Threads</h1>
<h2 align="center">mutex<br>
try_mutex<br>
timed_mutex</h2>
</td>
</tr>
</table>
<td valign="top">
<h1 align="center">Boost.Threads</h1>
<hr>
<h2 align="center">mutex<br>
try_mutex<br>
timed_mutex</h2>
</td>
</tr>
</table>
<hr>
<p><a href="#Introduction">Introduction</a><br>
<a href="#Header">Header</a><br>
<a href="#mutex Synopsis">Class mutex Synopsis</a><br>
<a href="#mutex Members">Class mutex Members</a><br>
<a href="#try_mutex Synopsis">Class try_mutex Synopsis</a><br>
<a href="#try_mutex Members">Class try_mutex Members</a><br>
<a href="#timed_mutex Synopsis">Class timed_mutex Synopsis</a><br>
<a href="#timed_mutex Members">Class timed_mutex Members</a><br>
<a href="#Example">Example</a></p>
<p><a href="#Introduction">Introduction</a><br>
<a href="#Header">Header</a><br>
<a href="#mutex Synopsis">Class mutex Synopsis</a><br>
<a href="#mutex Members">Class mutex Members</a><br>
<a href="#try_mutex Synopsis">Class try_mutex Synopsis</a><br>
<a href="#try_mutex Members">Class try_mutex Members</a><br>
<a href="#timed_mutex Synopsis">Class timed_mutex Synopsis</a><br>
<a href="#timed_mutex Members">Class timed_mutex Members</a><br>
<a href="#Example">Example</a></p>
<h2><a name="Introduction">Introduction</a></h2>
<h2><a name="Introduction">Introduction</a></h2>
<p>The <tt><a href="#mutex Synopsis">mutex</a></tt>, <tt><a href="#try_mutex Synopsis">try_mutex</a></tt> and <tt><a href="#timed_mutex Synopsis">timed_mutex</a></tt> classes define full featured
models of the <a href="mutex_concept.html#Mutex">Mutex</a>, <a href="mutex_concept.html#TryMutex">TryMutex</a>,
and <a href="mutex_concept.html#TimedMutex">TimedMutex</a> concepts. These types should be used to
non-recursively synchronize access to
shared resources. For recursive locking mechanics, see <a href="recursive_mutex.html">recursive
mutexes</a>.</p>
<p>The <tt><a href="#mutex Synopsis">mutex</a></tt>, <tt><a href=
"#try_mutex Synopsis">try_mutex</a></tt> and <tt><a href=
"#timed_mutex Synopsis">timed_mutex</a></tt> classes define full
featured models of the <a href="mutex_concept.html#Mutex">Mutex</a>, <a
href="mutex_concept.html#TryMutex">TryMutex</a>, and <a href=
"mutex_concept.html#TimedMutex">TimedMutex</a> concepts. These types
should be used to non-recursively synchronize access to shared
resources. For recursive locking mechanics, see <a href=
"recursive_mutex.html">recursive mutexes</a>.</p>
<p>Each class supplies one or more typedefs for lock types which model matching
lock concepts. For the best possible performance you should use the mutex class that supports
the minimum set of lock
types that you need.</p>
<p>Each class supplies one or more typedefs for lock types which model
matching lock concepts. For the best possible performance you should
use the mutex class that supports the minimum set of lock types that
you need.</p>
<table border="1" cellpadding="5">
<tr>
<td><b>Mutex Class</b></td>
<td><b>Lock name</b></td>
<td><b>Implementation defined Lock Type</b></td>
<td><b>&nbsp;Lock Concept</b></td>
</tr>
<tr>
<td valign="top"><a href="#mutex Synopsis"><code>mutex</code></a></td>
<td valign="middle"><code>scoped_lock</code></td>
<td valign="middle"><code><a href="scoped_lock.html">boost::</a></code><a href="scoped_lock.html"><code>detail::thread::scoped_lock&lt;mutex&gt;</code></a></td>
<td valign="middle"><a href="lock_concept.html#ScopedLock">ScopedLock</a></td>
</tr>
<tr>
<td valign="top"><tt><a href="#try_mutex Synopsis">try_mutex</a></tt> </td>
<td valign="middle"><code>scoped_lock<br>
scoped_try_lock</code></td>
<td valign="middle"><code><a href="scoped_lock.html">boost::</a></code><a href="scoped_lock.html"><code>detail::thread::scoped_lock&lt;try_mutex&gt;<br>
</code></a><code><a href="scoped_try_lock.html">boost::detail::thread::scoped_try_lock&lt;try_mutex&gt;</a></code></td>
<td valign="middle"><a href="lock_concept.html#ScopedLock">ScopedLock</a><br>
<a href="lock_concept.html#ScopedTryLock">ScopedTryLock</a></td>
</tr>
<tr>
<td valign="top"><code><a href="#timed_mutex Synopsis">timed_mutex</a></code> </td>
<td valign="middle"><code>scoped_lock<br>
scoped_try_lock<br>
scoped_timed_lock</code></td>
<td valign="middle"><code><a href="scoped_lock.html">boost::</a></code><a href="scoped_lock.html"><code>detail::thread::scoped_lock&lt;timed_mutex&gt;</code></a><br>
<code><a href="scoped_try_lock.html">boost::</a></code><a href="scoped_try_lock.html"><code>detail::thread::scoped_try_lock&lt;timed_mutex&gt;</code></a><br>
<code><a href="scoped_timed_lock.html">boost::</a></code><a href="scoped_timed_lock.html"><code>detail::thread::scoped_timed_lock&lt;timed_mutex&gt;</code></a></td>
<td valign="middle"><a href="lock_concept.html#ScopedLock">ScopedLock</a><br>
<a href="lock_concept.html#ScopedTryLock">ScopedTryLock</a><br>
<a href="lock_concept.html#ScopedTimedLock">ScopedTimedLock</a></td>
</tr>
</table>
<table summary="lock types" border="1" cellpadding="5">
<tr>
<td><b>Mutex Class</b></td>
<p>The <tt>mutex</tt>, <tt>try_mutex</tt> and <tt>timed_mutex</tt> classes use an <tt>Unspecified</tt>
<A href="mutex_concept.html#LockingStrategies">locking strategy</a>, so attempts to recursively lock
them or attempts to unlock them by threads that don't own a lock on them result in <b>undefined behavior</b>.
This strategy allows implementations to be as efficient as possible on any given platform. It is, however,
recommended that implementations include debugging support to detect misuse when <tt>NDEBUG</tt> is
not defined.</p>
<td><b>Lock name</b></td>
<p>Like all the <b>Boost.Threads</b> <A href="mutex_concept.html">mutex models</a>, the <tt>mutex</tt>,
<tt>try_mutex</tt> and <tt>timed_mutex</tt> leave the
<A href="mutex_concept.html#SchedulingPolicies">scheduling policy</a> as <tt>Unspecified</tt>.
Programmers should assume that threads waiting for a lock on objects of these types
acquire
the lock in a random order, even though the specific behavior for a given platform may be different.</p>
<td><b>Implementation defined Lock Type</b></td>
<h2><a name="Header">Header</a></h2>
<td><b>Lock Concept</b></td>
</tr>
<tr>
<td valign="top"><a href="#mutex Synopsis"><code>
mutex</code></a></td>
<td valign="middle"><code>scoped_lock</code></td>
<td valign="middle"><code><a href="scoped_lock.html">
boost::</a></code><a href=
"scoped_lock.html"><code>detail::thread::scoped_lock&lt;mutex&gt;</code></a></td>
<td valign="middle"><a href="lock_concept.html#ScopedLock">
ScopedLock</a></td>
</tr>
<tr>
<td valign="top"><tt><a href="#try_mutex Synopsis">
try_mutex</a></tt> </td>
<td valign="middle"><code>scoped_lock<br>
scoped_try_lock</code></td>
<td valign="middle"><code><a href="scoped_lock.html">
boost::</a></code><a href=
"scoped_lock.html"><code>detail::thread::scoped_lock&lt;try_mutex&gt;<br>
</code></a> <code><a href="scoped_try_lock.html">
boost::detail::thread::scoped_try_lock&lt;try_mutex&gt;</a></code></td>
<td valign="middle"><a href="lock_concept.html#ScopedLock">
ScopedLock</a><br>
<a href="lock_concept.html#ScopedTryLock">
ScopedTryLock</a></td>
</tr>
<tr>
<td valign="top"><code><a href="#timed_mutex Synopsis">
timed_mutex</a></code> </td>
<td valign="middle"><code>scoped_lock<br>
scoped_try_lock<br>
scoped_timed_lock</code></td>
<td valign="middle"><code><a href="scoped_lock.html">
boost::</a></code><a href=
"scoped_lock.html"><code>detail::thread::scoped_lock&lt;timed_mutex&gt;</code></a><br>
<code><a href="scoped_try_lock.html">boost::</a></code><a
href=
"scoped_try_lock.html"><code>detail::thread::scoped_try_lock&lt;timed_mutex&gt;</code></a><br>
<code><a href="scoped_timed_lock.html">boost::</a></code><a
href=
"scoped_timed_lock.html"><code>detail::thread::scoped_timed_lock&lt;timed_mutex&gt;</code></a></td>
<td valign="middle"><a href="lock_concept.html#ScopedLock">
ScopedLock</a><br>
<a href="lock_concept.html#ScopedTryLock">
ScopedTryLock</a><br>
<a href="lock_concept.html#ScopedTimedLock">
ScopedTimedLock</a></td>
</tr>
</table>
<p>The <tt>mutex</tt>, <tt>try_mutex</tt> and <tt>timed_mutex</tt>
classes use an <tt>Unspecified</tt> <a href=
"mutex_concept.html#LockingStrategies">locking strategy</a>, so
attempts to recursively lock them or attempts to unlock them by threads
that don&#39;t own a lock on them result in <b>undefined behavior</b>.
This strategy allows implementations to be as efficient as possible on
any given platform. It is, however, recommended that implementations
include debugging support to detect misuse when <tt>NDEBUG</tt> is not
defined.</p>
<p>Like all the <b>Boost.Threads</b> <a href="mutex_concept.html">mutex
models</a>, the <tt>mutex</tt>, <tt>try_mutex</tt> and <tt>
timed_mutex</tt> leave the <a href=
"mutex_concept.html#SchedulingPolicies">scheduling policy</a> as <tt>
Unspecified</tt>. Programmers should assume that threads waiting for a
lock on objects of these types acquire the lock in a random order, even
though the specific behavior for a given platform may be different.</p>
<h2><a name="Header">Header</a></h2>
<pre>
#include <a href="../../../boost/thread/mutex.hpp">&lt;boost/thread/mutex.hpp&gt;</a>
#include <a href=
"../../../boost/thread/mutex.hpp">&lt;boost/thread/mutex.hpp&gt;</a>
</pre>
<h2>Class <a name="mutex Synopsis"> mutex Synopsis</a></h2>
<h2>Class <a name="mutex Synopsis">mutex Synopsis</a></h2>
<pre>
namespace boost
{
class mutex : private <a href="../../utility/utility.htm">boost::noncopyable</a> // Exposition only.
// Class mutex meets the <a href="overview.html#NonCopyable">NonCopyable</a> requirement.
class mutex : private <a href=
"../../utility/utility.htm">boost::noncopyable</a> // Exposition only.
// Class mutex meets the <a href=
"overview.html#NonCopyable">NonCopyable</a> requirement.
{
public:
typedef <i>[implementation defined; see <a href="#Introduction">Introduction</a>]</i> scoped_lock;
typedef <i>[implementation defined; see <a href=
"#Introduction">Introduction</a>]</i> scoped_lock;
mutex();
~mutex();
@@ -122,50 +172,45 @@ namespace boost
}
</pre>
<h2>
Class <a name="mutex Members">mutex Members</a>
</h2>
<hr>
<h3>Constructor</h3>
<h2>Class <a name="mutex Members">mutex Members</a></h2>
<hr>
<h3>Constructor</h3>
<pre>
mutex();
</pre>
<p><b>Postconditions: </b><code>*this</code> is in the unlocked state.</p>
<hr>
<h3>Destructor</h3>
<p><b>Postconditions:</b> <code>*this</code> is in the unlocked
state.</p>
<hr>
<h3>Destructor</h3>
<pre>
~mutex();
</pre>
<p><b>Requires:</b> <code>*this</code> is in the unlocked state.</p>
<p><b>Requires:</b> <code>*this</code> is in the unlocked state.</p>
<p><b>Effects:</b> Destroys <code>*this</code>.</p>
<p><b>Effects:</b> Destroys <code>*this</code>.</p>
<p><b>Dangers:</b> Destruction of a locked mutex is a serious programming error
resulting in undefined behavior such as a program crash.</p>
<hr>
<h2>
Class <a name="try_mutex Synopsis">try_mutex Synopsis</a>
</h2>
<p><b>Dangers:</b> Destruction of a locked mutex is a serious
programming error resulting in undefined behavior such as a program
crash.</p>
<hr>
<h2>Class <a name="try_mutex Synopsis">try_mutex Synopsis</a></h2>
<pre>
namespace boost
{
class try_mutex : private boost::noncopyable // Exposition only.
// Class try_mutex meets the <a href="overview.html#NonCopyable">NonCopyable</a> requirement.
// Class try_mutex meets the <a href=
"overview.html#NonCopyable">NonCopyable</a> requirement.
{
public:
typedef <i>[implementation defined; see <a href="#Introduction">Introduction</a>]</i> scoped_lock;
typedef <i>[implementation defined; see <a href="#Introduction">Introduction</a>]</i> scoped_try_lock;
typedef <i>[implementation defined; see <a href=
"#Introduction">Introduction</a>]</i> scoped_lock;
typedef <i>[implementation defined; see <a href=
"#Introduction">Introduction</a>]</i> scoped_try_lock;
try_mutex();
~try_mutex();
@@ -173,49 +218,47 @@ namespace boost
}
</pre>
<h2>Class <a name="try_mutex Members">try_mutex Members</a></h2>
<hr>
<h3>Constructor</h3>
<h2>Class <a name="try_mutex Members">try_mutex Members</a></h2>
<hr>
<h3>Constructor</h3>
<pre>
try_mutex();
</pre>
<p><b>Postconditions: </b><code>*this</code> is in the unlocked state.</p>
<hr>
<h3>Destructor</h3>
<p><b>Postconditions:</b> <code>*this</code> is in the unlocked
state.</p>
<hr>
<h3>Destructor</h3>
<pre>
~try_mutex();
</pre>
<p><b>Requires:</b> <code>*this</code> is in the unlocked state.</p>
<p><b>Requires:</b> <code>*this</code> is in the unlocked state.</p>
<p><b>Effects:</b> Destroys <code>*this</code>.</p>
<p><b>Effects:</b> Destroys <code>*this</code>.</p>
<p><b>Dangers:</b> Destruction of a locked mutex is a serious programming error
resulting in undefined behavior such as a program crash.</p>
<hr>
<h2>
Class <a name="timed_mutex Synopsis">timed_mutex Synopsis</a>
</h2>
<p><b>Dangers:</b> Destruction of a locked mutex is a serious
programming error resulting in undefined behavior such as a program
crash.</p>
<hr>
<h2>Class <a name="timed_mutex Synopsis">timed_mutex Synopsis</a></h2>
<pre>
namespace boost
{
class timed_mutex : private boost::noncopyable // Exposition only.
// Class timed_mutex meets the <a href="overview.html#NonCopyable">NonCopyable</a> requirement.
// Class timed_mutex meets the <a href=
"overview.html#NonCopyable">NonCopyable</a> requirement.
{
public:
typedef <i>[implementation defined; see <a href="#Introduction">Introduction</a>]</i> scoped_lock;
typedef <i>[implementation defined; see <a href="#Introduction">Introduction</a>]</i> scoped_try_lock;
typedef <i>[implementation defined; see <a href="#Introduction">Introduction</a>]</i> scoped_timed_lock;
typedef <i>[implementation defined; see <a href=
"#Introduction">Introduction</a>]</i> scoped_lock;
typedef <i>[implementation defined; see <a href=
"#Introduction">Introduction</a>]</i> scoped_try_lock;
typedef <i>[implementation defined; see <a href=
"#Introduction">Introduction</a>]</i> scoped_timed_lock;
timed_mutex();
~timed_mutex();
@@ -223,43 +266,42 @@ namespace boost
}
</pre>
<h2>Class <a name="timed_mutex Members">timed_mutex Members</a></h2>
<hr>
<h3>Constructor</h3>
<h2>Class <a name="timed_mutex Members">timed_mutex Members</a></h2>
<hr>
<h3>Constructor</h3>
<pre>
timed_mutex();
</pre>
<p><b>Postconditions: </b><code>*this</code> is in the unlocked state.</p>
<hr>
<h3>Destructor</h3>
<p><b>Postconditions:</b> <code>*this</code> is in the unlocked
state.</p>
<hr>
<h3>Destructor</h3>
<pre>
~timed_mutex();
</pre>
<p><b>Requires:</b> <code>*this</code> is in the unlocked state.</p>
<p><b>Requires:</b> <code>*this</code> is in the unlocked state.</p>
<p><b>Effects:</b> Destroys <code>*this</code>.</p>
<p><b>Effects:</b> Destroys <code>*this</code>.</p>
<p><b>Dangers:</b> Destruction of a locked mutex is a serious programming error
resulting in undefined behavior such as a program crash.</p>
<hr>
<h2><a name="Example">Example</a> Usage</h2>
<p><b>Dangers:</b> Destruction of a locked mutex is a serious
programming error resulting in undefined behavior such as a program
crash.</p>
<hr>
<h2><a name="Example">Example</a> Usage</h2>
<pre>
#include <a href="../../../boost/thread/mutex.hpp">&lt;boost/thread/mutex.hpp&gt;</a>
#include <a href="../../../boost/thread/thread.hpp">&lt;boost/thread/thread.hpp&gt;</a>
#include <a href=
"../../../boost/thread/mutex.hpp">&lt;boost/thread/mutex.hpp&gt;</a>
#include <a href=
"../../../boost/thread/thread.hpp">&lt;boost/thread/thread.hpp&gt;</a>
#include &lt;iostream&gt;
boost::mutex io_mutex; // The iostreams are not guaranteed to be <a href="definitions.html#Thread-safe">thread-safe</a>!
boost::mutex io_mutex; // The iostreams are not guaranteed to be <a href=
"definitions.html#Thread-safe">thread-safe</a>!
class counter
{
@@ -278,7 +320,7 @@ private:
counter c;
void change_count(void*)
void change_count()
{
int i = c.increment();
boost::mutex::scoped_lock scoped_lock(io_mutex);
@@ -290,7 +332,7 @@ int main(int, char*[])
const int num_threads = 4;
boost::thread_group thrds;
for (int i=0; i &lt; num_threads; ++i)
thrds.create_thread(&amp;change_count, 0);
thrds.create_thread(&amp;change_count);
thrds.join_all();
@@ -298,22 +340,20 @@ int main(int, char*[])
}
</pre>
<p>The output is:</p>
<p>The output is:</p>
<pre>
count == 1
count == 2
count == 3
count == 4
</pre>
<hr>
<hr>
<p>Revised
<!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->05 November, 2001<!--webbot bot="Timestamp" endspan i-checksum="39359" --></p>
<p>Revised <!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->01 October, 2001<!--webbot bot="Timestamp" endspan i-checksum="38291" -->
</p>
<p><i>© Copyright <A href="mailto:williamkempf@hotmail.com">William E. Kempf</a>
2001 all rights reserved.</i></p>
</body>
<p><i>&copy; Copyright <a href="mailto:williamkempf@hotmail.com">
William E. Kempf</a> 2001 all rights reserved.</i></p>
</body>
</html>

View File

@@ -1,275 +1,337 @@
<html>
<head>
<meta http-equiv="Content-Type" content=
"text/html; charset=iso-8859-1">
<meta name="keywords" content="threads, BTL, thread library, C++">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<meta name="keywords" content="threads, BTL, thread library, C++">
<title>Boost.Threads, Mutex Concept</title>
</head>
<title>Boost.Threads, Mutex Concept</title>
</head>
<body bgcolor="#ffffff" link="#0000ff" vlink="#800080">
<body bgcolor="#ffffff" link="#0000ff" vlink="#800080">
<table summary="header" border="0" cellpadding="7" cellspacing="0"
width="100%">
<tr>
<td valign="top" width="300">
<h3><img height="86" alt="C++ Boost" src=
"../../../c++boost.gif" width="277"></h3>
</td>
<table border="0" cellpadding="7" cellspacing="0" width="100%">
<tr>
<td valign="top" width="300">
<h3><IMG height=86 alt="C++ Boost" src="../../../c++boost.gif" width=277></h3>
</td>
<td valign="top">
<h1 align="center">Boost.Threads</h1>
<h2 align="center">Mutex Concepts</h2>
</td>
</tr>
</table>
<td valign="top">
<h1 align="center">Boost.Threads</h1>
<hr>
<h2 align="center">Mutex Concepts</h2>
</td>
</tr>
</table>
<hr>
<p><a href="#Introduction">Introduction</a><br>
<a href="#LockingStrategies">Locking Strategies</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#Recursive">Recursive</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#CheckedStrategy">Checked</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#UncheckedStrategy">Unchecked</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#UnspecifiedStrategy">Unspecified</a><br>
<a href="#SchedulingPolicies">Scheduling Policies</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#FIFO">FIFO</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#Priority Driven">Priority Driven</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#UndefinedScheduling">Undefined</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#UnspecifiedScheduling">Unspecified</a><br>
<a href="#Requirements">Concept Requirements</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#Mutex">Mutex Concept</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#TryMutex">TryMutex Concept</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#TimedMutex">TimedMutex Concept</a><br>
<a href="#Models">Models</a></p>
<p><a href="#Introduction">Introduction</a><br>
<a href="#LockingStrategies">Locking Strategies</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#Recursive">Recursive</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#CheckedStrategy">Checked</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#UncheckedStrategy">Unchecked</a><br>
&nbsp;&nbsp;&nbsp;&nbsp; <a href="#UnspecifiedStrategy">
Unspecified</a><br>
<a href="#SchedulingPolicies">Scheduling Policies</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#FIFO">FIFO</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#Priority Driven">Priority
Driven</a><br>
&nbsp;&nbsp;&nbsp;&nbsp; <a href="#UndefinedScheduling">
Undefined</a><br>
&nbsp;&nbsp;&nbsp;&nbsp; <a href="#UnspecifiedScheduling">
Unspecified</a><br>
<a href="#Requirements">Concept Requirements</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#Mutex">Mutex Concept</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#TryMutex">TryMutex Concept</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#TimedMutex">TimedMutex
Concept</a><br>
<a href="#Models">Models</a></p>
<h2><a name="Introduction">Introduction</a></h2>
<h2><a name="Introduction">Introduction</a></h2>
<p>A mutex (short for mutual-exclusion) concept serializes access to
a resource shared between multiple threads. The <a href="#Mutex">Mutex</a>
concept, with <a href="#TryMutex">TryMutex</a> and <a href="#TimedMutex">TimedMutex</a>
refinements, formalize the requirements. A model that implements Mutex and its
refinements has two states: <b> locked</b> and <b>unlocked</b>. Before using a
shared resource, a thread locks a Boost.Threads mutex model object,
insuring <a href="definitions.html#Thread-safe">thread-safe</a> access to the shared
resource. When use of the shared resource is complete, the thread unlocks the mutex
model object, allowing another thread to acquire the lock and use the shared resource.</p>
<p>A mutex (short for mutual-exclusion) concept serializes access to a
resource shared between multiple threads. The <a href="#Mutex">
Mutex</a> concept, with <a href="#TryMutex">TryMutex</a> and <a href=
"#TimedMutex">TimedMutex</a> refinements, formalize the requirements. A
model that implements Mutex and its refinements has two states: <b>
locked</b> and <b>unlocked</b>. Before using a shared resource, a
thread locks a Boost.Threads mutex model object, insuring <a href=
"definitions.html#Thread-safe">thread-safe</a> access to the shared
resource. When use of the shared resource is complete, the thread
unlocks the mutex model object, allowing another thread to acquire the
lock and use the shared resource.</p>
<p>Traditional C thread APIs, like Pthreads or the Windows thread APIs, expose
functions to lock and unlock a mutex model. This is dangerous since it's easy to forget
to unlock a locked mutex. When the flow of control is complex, with multiple return
points, the likelihood of forgetting to unlock a mutex model would become even greater.
When exceptions are thrown, it becomes nearly impossible to ensure that the mutex is
unlocked properly when using these traditional API's. The result is
<a href="definitions.html#Deadlock">deadlock</a>.</p>
<p>Traditional C thread APIs, like Pthreads or the Windows thread APIs,
expose functions to lock and unlock a mutex model. This is dangerous
since it&#39;s easy to forget to unlock a locked mutex. When the flow
of control is complex, with multiple return points, the likelihood of
forgetting to unlock a mutex model would become even greater. When
exceptions are thrown, it becomes nearly impossible to ensure that the
mutex is unlocked properly when using these traditional API&#39;s. The
result is <a href="definitions.html#Deadlock">deadlock</a>.</p>
<p>Many C++ threading libraries use a pattern known as <i>Scoped Locking</i>
<a href="bibliography.html#Schmidt 00">[Schmidt 00]</a> to free the programmer from the
need to explicitly lock and unlock mutexes. With this pattern, a
<A href="lock_concept.html">lock concept</A> is employed where the lock model's
constructor locks the associated mutex model and the destructor automatically does the
unlocking. The <b>Boost.Threads</b> library takes this pattern to the extreme in that
lock concepts are the only way to lock and unlock a mutex model: lock and unlock
functions are not exposed by any <b>Boost.Threads </b>mutex models. This helps to
ensure safe usage patterns, especially when code throws exceptions.</p>
<p>Many C++ threading libraries use a pattern known as <i>Scoped
Locking</i> <a href="bibliography.html#Schmidt 00">[Schmidt 00]</a> to
free the programmer from the need to explicitly lock and unlock
mutexes. With this pattern, a <a href="lock_concept.html">lock
concept</a> is employed where the lock model&#39;s constructor locks
the associated mutex model and the destructor automatically does the
unlocking. The <b>Boost.Threads</b> library takes this pattern to the
extreme in that lock concepts are the only way to lock and unlock a
mutex model: lock and unlock functions are not exposed by any <b>
Boost.Threads</b> mutex models. This helps to ensure safe usage
patterns, especially when code throws exceptions.</p>
<h2><a name="LockingStrategies">Locking Strategies</a></h2>
<h2><a name="LockingStrategies">Locking Strategies</a></h2>
<p>Every mutex model follows one of several locking strategies. These strategies
define the semantics for the locking operation when the calling thread already
owns a lock on the mutex model.</p>
<p>Every mutex model follows one of several locking strategies. These
strategies define the semantics for the locking operation when the
calling thread already owns a lock on the mutex model.</p>
<h3><a name="Recursive">Recursive</a></h3>
<h3><a name="Recursive">Recursive</a></h3>
<p>With a recursive locking strategy when a thread attempts to acquire a lock on
the mutex model for which it already owns a lock, the operation is successful.
Note the distinction between a thread, which may have multiple locks outstanding
on a recursive mutex, and a lock object, which even for a recursive mutex cannot
have its lock() function called multiple times without first calling unlock().</p>
<p>With a recursive locking strategy when a thread attempts to acquire
a lock on the mutex model for which it already owns a lock, the
operation is successful. Note the distinction between a thread, which
may have multiple locks outstanding on a recursive mutex, and a lock
object, which even for a recursive mutex cannot have its lock()
function called multiple times without first calling unlock().</p>
<p>Internally a lock count is maintained and the owning thread must unlock the
mutex model the same number of times that it's locked it before the mutex model's
state returns to unlocked. Since mutex models in <b>Boost.Threads</b> expose
locking functionality only through lock concepts, a thread will always unlock a mutex
model the same number of times that it locked it. This helps to eliminate a whole set
of errors typically found in traditional C style thread APIs.</p>
<p>Internally a lock count is maintained and the owning thread must
unlock the mutex model the same number of times that it&#39;s locked it
before the mutex model&#39;s state returns to unlocked. Since mutex
models in <b>Boost.Threads</b> expose locking functionality only
through lock concepts, a thread will always unlock a mutex model the
same number of times that it locked it. This helps to eliminate a whole
set of errors typically found in traditional C style thread APIs.</p>
<p>Classes <A href="recursive_mutex.html">recursive_mutex</A>,
<A href="recursive_mutex.html">recursive_try_mutex</A> and
<A href="recursive_mutex.html">recursive_timed_mutex</A> use this locking strategy.</p>
<p>Classes <a href="recursive_mutex.html">recursive_mutex</a>, <a href=
"recursive_mutex.html">recursive_try_mutex</a> and <a href=
"recursive_mutex.html">recursive_timed_mutex</a> use this locking
strategy.</p>
<h3><a name="CheckedStrategy">Checked</a></h3>
<h3><a name="CheckedStrategy">Checked</a></h3>
<p>With a checked locking strategy when a thread attempts to acquire a lock on
the mutex model for which the thread already owns a lock, the operation will fail with
some sort of error indication. Further, attempts by a thread to unlock a mutex
that was not locked by the thread will also return some sort of error indication.
In <b>Boost.Threads</b>, an exception of type <A href="lock_error.html">lock_error</A>
would be thrown in these cases.</p>
<p>With a checked locking strategy when a thread attempts to acquire a
lock on the mutex model for which the thread already owns a lock, the
operation will fail with some sort of error indication. Further,
attempts by a thread to unlock a mutex that was not locked by the
thread will also return some sort of error indication. In <b>
Boost.Threads</b>, an exception of type <a href="lock_error.html">
lock_error</a> would be thrown in these cases.</p>
<p><b>Boost.Threads</b> does not currently provide any mutex models that use this
strategy.</p>
<p><b>Boost.Threads</b> does not currently provide any mutex models
that use this strategy.</p>
<h3><a name="UncheckedStrategy">Unchecked</a></h3>
<h3><a name="UncheckedStrategy">Unchecked</a></h3>
<p>With an unchecked locking strategy when a thread attempts to acquire a lock
on the mutex model for which the thread already owns a lock the operation will
<a href="definitions.html#Deadlock">deadlock</a>. In general this locking strategy is
less safe than a checked or recursive strategy, but it's also a faster strategy and so
is employed by many libraries.</p>
<p>With an unchecked locking strategy when a thread attempts to acquire
a lock on the mutex model for which the thread already owns a lock the
operation will <a href="definitions.html#Deadlock">deadlock</a>. In
general this locking strategy is less safe than a checked or recursive
strategy, but it&#39;s also a faster strategy and so is employed by
many libraries.</p>
<p><b>Boost.Threads</b> does not currently provide any mutex models that use this
strategy.</p>
<p><b>Boost.Threads</b> does not currently provide any mutex models
that use this strategy.</p>
<h3><a name="UnspecifiedStrategy">Unspecified</a></h3>
<h3><a name="UnspecifiedStrategy">Unspecified</a></h3>
<p>With an unspecified locking strategy, when a thread attempts to acquire a lock
on a mutex model for which the thread already owns a lock the operation results in
<b>undefined behavior</b>. When a mutex model has an unspecified locking strategy the
programmer must assume that the mutex model instead uses an unchecked strategy.</p>
<p>With an unspecified locking strategy, when a thread attempts to
acquire a lock on a mutex model for which the thread already owns a
lock the operation results in <b>undefined behavior</b>. When a mutex
model has an unspecified locking strategy the programmer must assume
that the mutex model instead uses an unchecked strategy.</p>
<p>In general a mutex model with an unspecified locking strategy is unsafe, and it
requires programmer discipline to use the mutex model properly. However, this strategy
allows an implementation to be as fast as possible with no restrictions on its
implementation. This is especially true for portable implementations that wrap the
native threading support of a platform. For this reason, the classes
<A href="mutex.html">mutex</A>, <A href="mutex.html">try_mutex</A> and
<A href="mutex.html">timed_mutex</A> use this locking strategy despite the lack of
safety.</p>
<p>In general a mutex model with an unspecified locking strategy is
unsafe, and it requires programmer discipline to use the mutex model
properly. However, this strategy allows an implementation to be as fast
as possible with no restrictions on its implementation. This is
especially true for portable implementations that wrap the native
threading support of a platform. For this reason, the classes <a href=
"mutex.html">mutex</a>, <a href="mutex.html">try_mutex</a> and <a href=
"mutex.html">timed_mutex</a> use this locking strategy despite the lack
of safety.</p>
<h2><a name="SchedulingPolicies">Scheduling Policies</a></h2>
<h2><a name="SchedulingPolicies">Scheduling Policies</a></h2>
<p>Every mutex model follows one of several scheduling policies. These policies
define the semantics when the mutex model is unlocked and there is more than one
thread waiting to acquire a lock. In other words, the policy defines which waiting
thread shall acquire the lock.</p>
<p>Every mutex model follows one of several scheduling policies. These
policies define the semantics when the mutex model is unlocked and
there is more than one thread waiting to acquire a lock. In other
words, the policy defines which waiting thread shall acquire the
lock.</p>
<h3><a name="FIFO">FIFO</a></h3>
<h3><a name="FIFO">FIFO</a></h3>
<p>With a FIFO scheduling policy, threads waiting for the lock will acquire it in
a first come first serve order (or First In First Out). This can help prevent a
high priority thread from starving lower priority threads that are also waiting
on the mutex lock.</p>
<p>With a FIFO scheduling policy, threads waiting for the lock will
acquire it in a first come first serve order (or First In First Out).
This can help prevent a high priority thread from starving lower
priority threads that are also waiting on the mutex lock.</p>
<h3><a name="Priority Driven">Priority Driven</a></h3>
<h3><a name="Priority Driven">Priority Driven</a></h3>
<p>With a Priority Driven scheduling policy, the thread with the highest priority
acquires the lock. Note that this means that low-priority threads may never acquire
the lock if the mutex model has high contention and there is always at least one
high-priority thread waiting. This is known as thread starvation. When multiple threads
of the same priority are waiting on the mutex lock one of the other scheduling
priorities will determine which thread shall acquire the lock.</p>
<p>With a Priority Driven scheduling policy, the thread with the
highest priority acquires the lock. Note that this means that
low-priority threads may never acquire the lock if the mutex model has
high contention and there is always at least one high-priority thread
waiting. This is known as thread starvation. When multiple threads of
the same priority are waiting on the mutex lock one of the other
scheduling priorities will determine which thread shall acquire the
lock.</p>
<h3><a name="UndefinedScheduling">Undefined</a></h3>
<h3><a name="UndefinedScheduling">Undefined</a></h3>
<p>Threads acquire the lock in no particular order. Users should assume that
low-priority threads may wait indefinitely, and that threads of the same
priority acquire the lock in essentially random order.</p>
<p>Threads acquire the lock in no particular order. Users should assume
that low-priority threads may wait indefinitely, and that threads of
the same priority acquire the lock in essentially random order.</p>
<h3><a name="UnspecifiedScheduling">Unspecified</a></h3>
<h3><a name="UnspecifiedScheduling">Unspecified</a></h3>
<p>The mutex model does not specify which scheduling policy is used. The programmer
must assume that an undefined scheduling policy is used. In order to ensure portability,
all <b>Boost.Threads</b> mutex models use an unspecified scheduling policy.</p>
<p>The mutex model does not specify which scheduling policy is used.
The programmer must assume that an undefined scheduling policy is used.
In order to ensure portability, all <b>Boost.Threads</b> mutex models
use an unspecified scheduling policy.</p>
<h2>Concept <a name="Requirements">Requirements</a></h2>
<h2>Concept <a name="Requirements">Requirements</a></h2>
<h3><a name="Mutex">Mutex</a> Concept</h3>
<h3><a name="Mutex">Mutex</a> Concept</h3>
<p>A Mutex object has two states: locked and unlocked. Mutex object state can only be
determined by an object meeting the <a href="lock_concept.html#ScopedLock">ScopedLock</a>
requirements and constructed for the Mutex object.</p>
<p>A Mutex object has two states: locked and unlocked. Mutex object
state can only be determined by an object meeting the <a href=
"lock_concept.html#ScopedLock">ScopedLock</a> requirements and
constructed for the Mutex object.</p>
<p>A Mutex is <a href="../../utility/utility.htm#Class noncopyable">noncopyable</a>.</p>
<p>A Mutex is <a href="../../utility/utility.htm#Class noncopyable">
noncopyable</a>.</p>
<p>For a Mutex type M and an object m of that type, the following expressions must be
well-formed and have the indicated effects.</p>
<p>For a Mutex type M and an object m of that type, the following
expressions must be well-formed and have the indicated effects.</p>
<table border="1" cellpadding="5">
<tr>
<td><b>Expression</b></td>
<td><b>Effects</b></td>
</tr>
<tr>
<td><code>M m;</code></td>
<td>Constructs a mutex object m. Post-condition: m is unlocked.</td>
</tr>
<tr>
<td><code>(&amp;m)-&gt;~M();</code></td>
<td>Precondition: m is unlocked. Destroys a mutex object m.</td>
</tr>
<tr>
<td><code>M::scoped_lock</code></td>
<td>A type meeting the <a href="lock_concept.html#ScopedLock">ScopedLock</a>
requirements.</td>
</tr>
</table>
<table summary="Mutex expressions" border="1" cellpadding="5">
<tr>
<td><b>Expression</b></td>
<h3><a name="TryMutex">TryMutex</a> Concept</h3>
<p>A TryMutex must meet the <a href="#Mutex"> Mutex</a> requirements. In addition, for a
TryMutex type M and an object m of that type, the following expressions must be
well-formed and have the indicated effects.</p>
<table border="1" cellpadding="5">
<tr>
<td><b>Expression</b></td>
<td><b>Effects</b></td>
</tr>
<tr>
<td><code>M::scoped_try_lock</code></td>
<td>A type meeting the <a href="lock_concept.html#ScopedTryLock">ScopedTryLock</a>
requirements.</td>
</tr>
</table>
<h3><a name="TimedMutex">TimedMutex</a> Concept</h3>
<p>A TimedMutex must meet the <a href="#TryMutex"> TryMutex</a> requirements. In addition, for a
TimedMutex type M and an object m of that type, the following
expressions must be well-formed and have the indicated effects.</p>
<table border="1" cellpadding="5">
<tr>
<td><b>Expression</b></td>
<td><b>Effects</b></td>
</tr>
<tr>
<td><code>M::scoped_timed_lock</code></td>
<td>A type meeting the <a href="lock_concept.html#ScopedTimedLock">ScopedTimedLock</a>
requirements.</td>
</tr>
</table>
<td><b>Effects</b></td>
</tr>
<h2><a name="Models">Models</a></h2>
<tr>
<td><code>M m;</code></td>
<p> <b>Boost.Threads</b> currently supplies six classes which model mutex
concepts.</p>
<td>Constructs a mutex object m. Post-condition: m is
unlocked.</td>
</tr>
<table border="1" cellpadding="5">
<tr>
<td><b>Concept</b></td>
<td><b>Refines</b></td>
<td><b>Classes Modeling the Concept</b></td>
</tr>
<tr>
<td valign="top"><a href="#Mutex">Mutex</a></td>
<td valign="top">&nbsp;</td>
<td><A href="mutex.html">mutex</A><br>
<A href="recursive_mutex.html">recursive_mutex</A></td>
</tr>
<tr>
<td valign="top"><a href="#TryMutex">TryMutex</a></td>
<td valign="top"><a href="#Mutex">Mutex</a></td>
<td><A href="mutex.html">try_mutex<br>
</A><A href="recursive_mutex.html">recursive_try_mutex</A> </td>
</tr>
<tr>
<td valign="top"><a href="#TimedMutex">TimedMutex</a></td>
<td valign="top"><a href="#TryMutex">TryMutex</a></td>
<td><A href="mutex.html">timed_mutex<br>
</A><A href="recursive_mutex.html">recursive_timed_mutex</A></td>
</tr>
</table>
<tr>
<td><code>(&amp;m)-&gt;~M();</code></td>
<hr>
<td>Precondition: m is unlocked. Destroys a mutex object
m.</td>
</tr>
<p>Revised <!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->01 October, 2001<!--webbot bot="Timestamp" endspan i-checksum="38291" -->
</p>
<tr>
<td><code>M::scoped_lock</code></td>
<p><i>© Copyright <A href="mailto:williamkempf@hotmail.com">William E. Kempf</A>
2001 all rights reserved.</i></p>
<td>A type meeting the <a href="lock_concept.html#ScopedLock">
ScopedLock</a> requirements.</td>
</tr>
</table>
</body>
<h3><a name="TryMutex">TryMutex</a> Concept</h3>
<p>A TryMutex must meet the <a href="#Mutex">Mutex</a> requirements. In
addition, for a TryMutex type M and an object m of that type, the
following expressions must be well-formed and have the indicated
effects.</p>
<table summary="TryMutex expressions" border="1" cellpadding="5">
<tr>
<td><b>Expression</b></td>
<td><b>Effects</b></td>
</tr>
<tr>
<td><code>M::scoped_try_lock</code></td>
<td>A type meeting the <a href=
"lock_concept.html#ScopedTryLock">ScopedTryLock</a>
requirements.</td>
</tr>
</table>
<h3><a name="TimedMutex">TimedMutex</a> Concept</h3>
<p>A TimedMutex must meet the <a href="#TryMutex">TryMutex</a>
requirements. In addition, for a TimedMutex type M and an object m of
that type, the following expressions must be well-formed and have the
indicated effects.</p>
<table summary="TimedMutex expressions" border="1" cellpadding="5">
<tr>
<td><b>Expression</b></td>
<td><b>Effects</b></td>
</tr>
<tr>
<td><code>M::scoped_timed_lock</code></td>
<td>A type meeting the <a href=
"lock_concept.html#ScopedTimedLock">ScopedTimedLock</a>
requirements.</td>
</tr>
</table>
<h2><a name="Models">Models</a></h2>
<p><b>Boost.Threads</b> currently supplies six classes which model
mutex concepts.</p>
<table summary="Mutex concept classes" border="1" cellpadding="5">
<tr>
<td><b>Concept</b></td>
<td><b>Refines</b></td>
<td><b>Classes Modeling the Concept</b></td>
</tr>
<tr>
<td valign="top"><a href="#Mutex">Mutex</a></td>
<td valign="top">&nbsp;</td>
<td><a href="mutex.html">mutex</a><br>
<a href="recursive_mutex.html">recursive_mutex</a></td>
</tr>
<tr>
<td valign="top"><a href="#TryMutex">TryMutex</a></td>
<td valign="top"><a href="#Mutex">Mutex</a></td>
<td><a href="mutex.html">try_mutex<br>
</a> <a href="recursive_mutex.html">recursive_try_mutex</a>
</td>
</tr>
<tr>
<td valign="top"><a href="#TimedMutex">TimedMutex</a></td>
<td valign="top"><a href="#TryMutex">TryMutex</a></td>
<td><a href="mutex.html">timed_mutex<br>
</a> <a href="recursive_mutex.html">
recursive_timed_mutex</a></td>
</tr>
</table>
<hr>
<p>Revised
<!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->05 November, 2001<!--webbot bot="Timestamp" endspan i-checksum="39359" --></p>
<p><i>&copy; Copyright <a href="mailto:williamkempf@hotmail.com">
William E. Kempf</a> 2001 all rights reserved.</i></p>
</body>
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<h3><IMG height=86 alt="C++ Boost" src="../../../c++boost.gif" width=277></h3>
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<h1 align="center">Boost.Threads</h1>
<h2 align="center">Overview</h2>
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<td valign="top">
<h1 align="center">Boost.Threads</h1>
<h2 align="center">Overview</h2>
</td>
</tr>
</table>
<p><a href="#Introduction">Introduction</a><br>
<a href="#Dangers">Dangers</a><br>
<a href="#Library">C++ Standard Library usage</a><br>
<a href="#Common">Common requirements</a></p>
<h2><a name="Introduction">Introduction</a></h2>
<p>Boost.Threads allows C++ programs to execute as multiple, asynchronous,
independent, threads-of-execution. Each thread has its own machine state
including program instruction counter and registers. Programs which execute as
multiple threads are call multi-threaded programs to distinguish them from
traditional single-threaded programs. <a href="definitions.html">Definitions</a>
gives a more complete description of the multi-threading execution environment.</p>
<hr>
<dl class="index">
<dt><a href="#introduction">Introduction</a></dt>
<dt><a href="#dangers">Dangers</a></dt>
<dl class="index">
<dt><a href="#testing-debugging">Testing and debugging considerations</a></dt>
<dt><a href="#head-start">Getting a head start</a></dt>
</dl>
<dt><a href="#library">C++ Standard Library usage in multi-threaded programs</a></dt>
<dl class="index">
<dt><a href="#runtime-libraries">Runtime libraries</a></dt>
<dt><a href="#non-thread-safe-functions">Potentially non-thread-safe functions</a></dt>
</dl>
<dt><a href="#common-requirements">Common requirements for all Boost.Threads components</a></dt>
<dl class="index">
<dt><a href="#exceptions">Exceptions</a></dt>
<dt><a href="#non-copyable">NonCopyable requirement</a></dt>
</dl>
</dl>
<h2><a name="introduction"></a>Introduction</h2>
<p>Boost.Threads allows C++ programs to execute as multiple, asynchronous, independent,
threads-of-execution. Each thread has its own machine state including program
instruction counter and registers. Programs which execute as multiple threads
are called multi-threaded programs to distinguish them from traditional single-threaded
programs. <a href="definitions.html">Definitions</a> gives a more complete description
of the multi-threading execution environment.</p>
<p>Multi-threading provides several advantages:</p>
<ul>
<li>Programs which would otherwise block waiting for some external event can
continue to respond if the blocking operation is placed in a separate
thread.&nbsp; Multi-threading is usually an absolute requirement for these
programs.</li>
<li>Programs which would otherwise block waiting for some external event can
continue to respond if the blocking operation is placed in a separate thread.
Multi-threading is usually an absolute requirement for these programs.</li>
</ul>
<ul>
<li>Well-designed multi-threaded programs may execute faster than single-threaded
programs, particularly on multi-processor hardware.&nbsp;
Note, however, that poorly-designed multi-threaded programs are often slower
that single-threaded programs.</li>
<li>Well-designed multi-threaded programs may execute faster than single-threaded
programs, particularly on multi-processor hardware. Note, however, that poorly-designed
multi-threaded programs are often slower that single-threaded programs.</li>
</ul>
<ul>
<li>Some program designs may be easier to formulate using a multi-threaded
approach.
After all, the real world is asynchronous!&nbsp;</li>
<li>Some program designs may be easier to formulate using a multi-threaded approach.
After all, the real world is asynchronous!</li>
</ul>
<h2><a name="Dangers">Dangers</a></h2>
<p>Beyond the errors which can occur in single-threaded programs, multi-threaded
programs are subject to additional errors:</p>
<h2><a name="dangers"></a>Dangers</h2>
<p>Beyond the errors which can occur in single-threaded programs, multi-threaded
programs are subject to additional errors:</p>
<ul>
<li><a href="definitions.html#Race condition">Race conditions</a>.
<li><a href="definitions.html#Deadlock">Deadlock</a> (sometimes called
&quot;deadly embrace&quot;)
<li><a href="definitions.html#Priority failure">Priority failures</a>
(priority inversion, infinite overtaking, starvation, etc.)</li>
<li><a href="definitions.html#Race condition">Race conditions</a>.</li>
<li><a href="definitions.html#Deadlock">Deadlock</a> (sometimes called &quot;deadly
embrace&quot;)</li>
<li><a href="definitions.html#Priority failure">Priority failures</a> (priority
inversion, infinite overtaking, starvation, etc.)</li>
</ul>
<p>Every multi-threaded program must be designed carefully to avoid race
conditions and deadlock.&nbsp; These aren't rare or exotic failures - they are
virtually guaranteed to occur unless multi-threaded code is designed to avoid
them.&nbsp; Priority failures are somewhat less common, but are none-the-less
serious.</p>
<p>The <a href="introduction.html">Boost.Threads design</a> attempts to minimize
these errors, but they will still occur unless the programmer proactively
designs to avoid them.</p>
<h3>Testing and debugging considerations</h3>
<p>Multi-threaded programs are non-deterministic. In other words, the same
program with the same input data may follow different execution paths each time
it is invoked.&nbsp; That can make testing and debugging a nightmare:</p>
<p>Every multi-threaded program must be designed carefully to avoid race conditions
and deadlock. These aren&#39;t rare or exotic failures - they are virtually
guaranteed to occur unless multi-threaded code is designed to avoid them. Priority
failures are somewhat less common, but are none-the-less serious.</p>
<p>The <a href="introduction.html">Boost.Threads design</a> attempts to minimize
these errors, but they will still occur unless the programmer proactively designs
to avoid them.</p>
<h3><a name="testing-debugging"></a>Testing and debugging considerations</h3>
<p>Multi-threaded programs are non-deterministic. In other words, the same program
with the same input data may follow different execution paths each time it is
invoked. That can make testing and debugging a nightmare:</p>
<ul>
<li>Failures are often not repeatable.
<li>Probe effect causes debuggers to produce very different results from
non-debug uses.
<li>Debuggers require special support to show thread state.
<li>Tests on a single processor system may give no indication of serious
errors which would appear on multiprocessor systems, and visa versa. Thus test
cases should include a varying number of processors.&nbsp;</li>
<li>For programs which create a varying number of threads according to
workload, tests which don't span the full range of possibilities may miss
serious errors.</li>
<li>Failures are often not repeatable.</li>
<li>Probe effect causes debuggers to produce very different results from non-debug
uses.</li>
<li>Debuggers require special support to show thread state.</li>
<li>Tests on a single processor system may give no indication of serious errors
which would appear on multiprocessor systems, and visa versa. Thus test cases
should include a varying number of processors.</li>
<li>For programs which create a varying number of threads according to workload,
tests which don&#39;t span the full range of possibilities may miss serious
errors.</li>
</ul>
<h3>Getting a head start</h3>
<p>Although it might appear that multi-threaded programs are inherently
unreliable, many reliable multi-threaded programs do exist. Multi-threading
techniques are known which lead to reliable programs.</p>
<p>Design patterns for reliable multi-threaded programs, including the important
<i>monitor</i> pattern, are presented in <cite>Pattern-Oriented Software Architecture Volume 2 - Patterns for
Concurrent and Networked Objects</cite> [<a href="bibliography.html#Schmidt-00">Schmidt
00</a>].&nbsp; Many important multi-threading programming considerations
(independent of threading library) are discussed in <cite>Programming with
POSIX Threads</cite> [<a href="bibliography.html#Butenhof-97">Butenhof 97</a>].</p>
<p>Reading and study first yields a head start toward designing reliable
multi-threaded programs.</p>
<h2><a name="Library">C++ Standard Library usage in multi-threaded programs</a></h2>
<h3>Runtime libraries</h3>
<p><b>Warning:</b> Multi-threaded programs such as those using <b>Boost.Threads</b> must link to
<a href="definitions.html#Thread-safe">thread-safe</a> versions of all runtime
libraries used by the program, including the runtime library for the C++
Standard Library. Otherwise <a href="definitions.html#Race condition">race
conditions</a> will occur when multiple threads simultaneously execute runtime
library functions for <i>new</i>, <i>delete</i>, or other language features
which imply shared state.&nbsp;&nbsp;</p>
<h3>Potentially non-thread-safe functions</h3>
<p>Certain C++ Standard Library functions inherited from C are particular
problems because they hold internal state between calls:</p>
<h3><a name="head-start"></a>Getting a head start</h3>
<p>Although it might appear that multi-threaded programs are inherently unreliable,
many reliable multi-threaded programs do exist. Multi-threading techniques are
known which lead to reliable programs.</p>
<p>Design patterns for reliable multi-threaded programs, including the important
<i>monitor</i> pattern, are presented in <cite> Pattern-Oriented Software Architecture
Volume 2 - Patterns for Concurrent and Networked Objects</cite> [<a href=
"bibliography.html#Schmidt-00">Schmidt 00</a>]. Many important multi-threading
programming considerations (independent of threading library) are discussed
in <cite>Programming with POSIX Threads</cite> [<a href="bibliography.html#Butenhof-97">Butenhof
97</a>].</p>
<p>Doing some reading before attempting multi-threaded designs will give you a
head start toward reliable multi-threaded programs.</p>
<h2><a name="library"></a>C++ Standard Library usage in multi-threaded programs</h2>
<h3><a name="runtime-libraries"></a>Runtime libraries</h3>
<p><b>Warning:</b> Multi-threaded programs such as those using <b> Boost.Threads</b>
must link to <a href="definitions.html#Thread-safe"> thread-safe</a> versions
of all runtime libraries used by the program, including the runtime library
for the C++ Standard Library. Otherwise <a href="definitions.html#Race condition">race
conditions</a> will occur when multiple threads simultaneously execute runtime
library functions for <i>new</i>, <i>delete</i>, or other language features
which imply shared state.</p>
<h3><a name="non-thread-safe-functions"></a>Potentially non-thread-safe functions</h3>
<p>Certain C++ Standard Library functions inherited from C are particular problems
because they hold internal state between calls:</p>
<ul>
<li>rand</li>
<li>strtok</li>
<li>asctime</li>
<li>ctime&nbsp;</li>
<li>ctime</li>
<li>gmtime</li>
<li>localtime</li>
</ul>
<p>It is possible to write thread-safe implementations of these by using <a href="thread_specific_ptr.html">thread-specific
storage</a>, and several C++ compiler vendors do just that.&nbsp; The technique
is well-know and is explained in [<a href="bibliography.html#Butenhof-97">Buttenhof-97</a>].</p>
<p>But at least one vendor (HP-UX) does not provide thread-safe implementations
of the above functions in their otherwise thread-safe runtime library.&nbsp;
Instead they provide replacement functions with different names and arguments.</p>
<p><b>Recommendation:</b> For the most portable, yet thread-safe code, use Boost
replacements for the problem functions.&nbsp; See the <a href="../../random/index.html">Boost
Random Number Library</a> and <a href="../../tokenizer/index.htm">Boost
Tokenizer Library</a>.</p>
<h2><a name="Common">Common</a> requirements for all Boost.Threads components</h2>
<h3>Exceptions</h3>
<p> <b>Boost.Threads</b> destructors never throw exceptions. Unless otherwise
specified, other <b>Boost.Threads</b>
functions that do not have an exception-specification may throw implementation-defined exceptions.</p>
<p>In particular, <b>Boost.Threads</b> reports failure to allocate storage by throwing an exception of type
std::bad_alloc, or a class derived from std::bad_alloc, failure to obtain
thread resources other than memory by throwing an exception of type <a href="thread_resource_error.html">boost::thread_resource_error</a>,
and certain lock related failures by throwing an exception of type <a href="lock_error.html">boost::lock_error</a></p>
<p><b>Rationale: </b>Follows the C++ Standard Library practice of allowing all
functions except destructors or other specified functions to throw exceptions on
errors.</p>
<h3><a name="NonCopyable">NonCopyable</a> requirement</h3>
<p><b>Boost.Threads</b> classes documented as meeting the NonCopyable requirement disallow copy
construction and copy assignment. For the sake of exposition, the synopsis of
such classes show private derivation from <a href="../../utility/utility.htm">boost::noncopyable</a>.
Users should not depend on this derivation, however, as implementations are free
to meet the NonCopyable requirement in other ways.</p>
<p>It is possible to write thread-safe implementations of these by using <a href="thread_specific_ptr.html">thread-specific
storage</a>, and several C++ compiler vendors do just that. The technique is
well-know and is explained in [<a href=
"bibliography.html#Butenhof-97">Buttenhof-97</a>].</p>
<p>But at least one vendor (HP-UX) does not provide thread-safe implementations
of the above functions in their otherwise thread-safe runtime library. Instead
they provide replacement functions with different names and arguments.</p>
<p><b>Recommendation:</b> For the most portable, yet thread-safe code, use Boost
replacements for the problem functions. See the <a href=
"../../random/index.html">Boost Random Number Library</a> and <a href=
"../../tokenizer/index.htm">Boost Tokenizer Library</a>.</p>
<h2><a name="common-requirements"></a>Common requirements for all Boost.Threads components</h2>
<h3><a name="exceptions"></a>Exceptions</h3>
<p><b>Boost.Threads</b> destructors never throw exceptions. Unless otherwise specified,
other <b>Boost.Threads</b> functions that do not have an exception-specification
may throw implementation-defined exceptions.</p>
<p>In particular, <b>Boost.Threads</b> reports failure to allocate storage by
throwing an exception of type std::bad_alloc, or a class derived from std::bad_alloc,
failure to obtain thread resources other than memory by throwing an exception
of type <a href=
"thread_resource_error.html">boost::thread_resource_error</a>, and certain
lock related failures by throwing an exception of type <a href=
"lock_error.html">boost::lock_error</a></p>
<p><b>Rationale:</b> Follows the C++ Standard Library practice of allowing all
functions except destructors or other specified functions to throw exceptions
on errors.</p>
<h3><a name="non-copyable"></a>NonCopyable requirement</h3>
<p><b>Boost.Threads</b> classes documented as meeting the NonCopyable requirement
disallow copy construction and copy assignment. For the sake of exposition,
the synopsis of such classes show private derivation from <a href="../../utility/utility.htm">
boost::noncopyable</a>. Users should not depend on this derivation, however,
as implementations are free to meet the NonCopyable requirement in other ways.</p>
<hr>
<p>Revised <!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->01 October, 2001<!--webbot bot="Timestamp" endspan i-checksum="38291" -->
<p>Revised
<!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->
05 November, 2001
<!--webbot bot="Timestamp" endspan i-checksum="39359" -->
</p>
<p>© Copyright 2001 Beman Dawes</p>
<p><i>&copy; Copyright <a href="mailto:wekempf@cox.net">William E. Kempf</a> 2001-2002.
All Rights Reserved.</i></p>
<p>Permission to use, copy, modify, distribute and sell this software and its
documentation for any purpose is hereby granted without fee, provided that the
above copyright notice appear in all copies and that both that copyright notice
and this permission notice appear in supporting documentation. William E. Kempf
makes no representations about the suitability of this software for any purpose.
It is provided &quot;as is&quot; without express or implied warranty.</p>
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<p>This page explains the rationale behind various design decisions in the <b> Boost.Threads</b>
library. Having the rationale documented here should explain how we arrived at the current
design as well as prevent future rehashing of discussions and thought processes that have
already occurred. It can also give users a lot of insight into the design process required
for this library.</p>
<h2><a name="library">Rationale for the Creation of Boost.Threads</a></h2>
<p>Processes often have a degree of "potential parallelism" and it can often be more intuitive
to design systems with this in mind. Further, these parallel processes can result in more responsive
programs. The benefits for multi-threaded programming are quite well known to most modern programmers,
yet the C++ language doesn't directly support this concept.</p>
<p>Many platforms support multi-threaded programming despite the fact that the language doesn't support
it. They do this through external libraries, which are, unfortunately, platform specific. POSIX has
tried to address this problem through the standardization of a "pthread" library. However, this
is a standard only on POSIX platforms, so its portability is limited.</p>
<p>Another problem with POSIX and other platform specific thread libraries is that they are
almost universally C based libraries. This leaves several C++ specific issues unresolved, such
as what happens when an exception is thrown in a thread. Further, there are some C++ concepts,
such as destructors, that can make usage much easier than what's available in a C library.</p>
<p>What's truly needed is C++ language support for threads. However, the C++ standards committee needs
existing practice or a good proposal as a starting point for adding this to the standard.</p>
<p>The Boost.Threads library was developed to provide a C++ developer with a portable interface
for writing multi-threaded programs on numerous platforms. There's a hope that the library can
be the basis for a more detailed proposal for the C++ standards committee to consider for inclusion
in the next C++ standard.</p>
<h2><a name="primitives">Rationale for the Low Level Primitives Supported in Boost.Threads</a></h2>
<p>The Boost.Threads library supplies a set of low level primitives for writing multi-threaded
programs, such as semaphores, mutexes and condition variables. In fact, the first release of
Boost.Threads supports only these low level primitives. However, computer
science research has shown
that use of these primitives is difficult since there's no way to mathematically prove that a
usage pattern is correct, meaning it doesn't result in race conditions or deadlocks. There
are several algebras (such as CSP, CCS and Join calculus) that have been developed to help write
provably correct parallel processes. In order to prove the correctness these processes must
be coded using higher level abstractions. So why does Boost.Threads support the lower level
concepts?</p>
<p>The reason is simple: the higher level concepts need to be implemented using at least some
of the lower level concepts. So having portable lower level concepts makes it easier to develop
the higher level concepts and will allow researchers to experiment with various techniques.</p>
<p>Beyond this theoretical application of higher level concepts, however, the fact remains that
many multi-threaded programs are written using only the lower level concepts, so they are
useful in and of themselves, even if it's hard to prove that their usage is correct. Since
many users will be familiar with these lower level concepts but be unfamiliar with any of the
higher level concepts there's also an argument for accessibility.</p>
<h2><a name="lock_objects">Rationale for the Lock Design</a></h2>
<p>Programmers who are used to multi-threaded programming issues will quickly note that the
Boost.Thread's design for mutex lock concepts is not <a href="definitions.html#Thread-safe">thread-safe</a>
(this is clearly documented
as well). At first this may seem like a serious design flaw. Why have a multi-threading primitive
that's not thread-safe itself?</p>
<p>A lock object is not a synchronization primitive. A lock object's sole responsibility is
to ensure that a mutex is both locked and unlocked in a manner that won't result in the common
error of locking a mutex and then forgetting to unlock it. This means that instances of a
lock object are only going to be created, at least in theory, within block scope and won't
be shared between threads. Only the mutex objects will be created outside of block scope and/or
shared between threads. Though it's possible to create a lock object outside of block scope and
to share it between threads to do so would not be a typical usage. Nor are there any cases when
such usage would be required.</p>
<p>Lock objects must maintain some state information. In order to allow a program to determine
if a try_lock or timed_lock was successful the lock object must retain state indicating
the success or failure of the call made in its constructor. If a lock object were to have
such state and remain thread-safe it would need to synchronize access to the state information
which would result in roughly doubling the time of most operations. Worse, since checking
the state can occur only by a call after construction we'd have a race condition if the lock
object were shared between threads.</p>
<p>So, to avoid the overhead of synchronizing access to the state information and to avoid
the race condition the Boost.Threads library simply does nothing to make lock objects thread-safe. Instead, sharing a lock object between threads results in undefined behavior. Since the
only proper usage of lock objects is within block scope this isn't a problem, and so long
as the lock object is properly used there's no danger of any multi-threading issues.</p>
<h2><a name="thread">Rationale for Non-copyable Thread Type</a></h2>
<p>Programmers who are used to C libraries for multi-threaded programming are likely to
wonder why Boost.Threads uses a non-copyable design for <a href="thread.html">boost::thread</a>. After all, the C
thread types are copyable, and you often have a need for copying them within user code.
However, careful comparison of C designs to C++ designs shows a flaw in this logic.</p>
<p>All C types are copyable. It is, in fact, not possible to make a non-copyable type in
C. For this reason types that represent system resources in C are often designed to behave
very similarly to a pointer to dynamic memory. There's an API for acquiring the resource
and an API for releasing the resources. For memory we have pointers as the type and
alloc/free for the acquisition and release APIs. For files we have FILE* as the type
and fopen/fclose for the acquisition and release APIs. You can freely copy instances of the
types but must manually manage the lifetime of the actual resource through the acquisition
and release APIs.</p>
<p>C++ designs recognize that the acquisition and release APIs are error prone and try
to eliminate possible errors by acquiring the resource in the constructor and releasing it
in the destructor. The best example of such a design is the std::iostream set of classes
which can represent the same resource as the FILE* type in C. A file is opened in the
std::fstream's constructor and closed in its destructor. However, if an iostream were
copyable it could lead to a file being closed twice, an obvious error, so the std::iostream
types are noncopyable by design. This is the same design used by boost::thread, which
is a simple and easy to understand design that's consistent with other C++ standard types.</p>
<p>During the design of boost::thread it was pointed out that it would be possible to allow
it to be a copyable type if some form of "reference management" were used, such as ref-counting
or ref-lists, and many argued for a boost::thread_ref design instead. The reasoning was
that copying "thread" objects was a typical need in the C libraries, and so presumably would
be in the C++ libraries as well. It was also thought that implementations could provide
more efficient reference management then wrappers (such as boost::shared_ptr) around a noncopyable
thread concept. Analysis of whether or not these arguments would hold true don't appear to
bear them out. To illustrate the analysis we'll first provide pseudo-code illustrating the six
typical usage patterns of a thread object.</p>
<dl class="index">
<dt><a href="#introduction">Introduction</a></dt>
<dt><a href="#library">Rationale for the Creation of <b>Boost.Threads</b></a></dt>
<dt><a href="#primitives">Rationale for the Low Level Primitives Supported in
<b>Boost.Threads</b></a></dt>
<dt><a href="#lock_objects">Rationale for the Lock Design</a></dt>
<dt><a href="#non-copyable">Rationale for Non-copyable Thread Type</a></dt>
<dt><a href="#events">Rationale for not providing <i>Event Variables</i></a></dt>
</dl>
<h2><a name="introduction"></a>Introduction</h2>
<p>This page explains the rationale behind various design decisions in the <b>Boost.Threads</b>
library. Having the rationale documented here should explain how we arrived
at the current design as well as prevent future rehashing of discussions and
thought processes that have already occurred. It can also give users a lot of
insight into the design process required for this library.</p>
<h2><a name="library"></a>Rationale for the Creation of <b>Boost.Threads</b></h2>
<p>Processes often have a degree of &quot;potential parallelism&quot; and it can
often be more intuitive to design systems with this in mind. Further, these
parallel processes can result in more responsive programs. The benefits for
multi-threaded programming are quite well known to most modern programmers,
yet the C++ language doesn&#39;t directly support this concept.</p>
<p>Many platforms support multi-threaded programming despite the fact that the
language doesn&#39;t support it. They do this through external libraries, which
are, unfortunately, platform specific. POSIX has tried to address this problem
through the standardization of a &quot;pthread&quot; library. However, this
is a standard only on POSIX platforms, so its portability is limited.</p>
<p>Another problem with POSIX and other platform specific thread libraries is
that they are almost universally C based libraries. This leaves several C++
specific issues unresolved, such as what happens when an exception is thrown
in a thread. Further, there are some C++ concepts, such as destructors, that
can make usage much easier than what&#39;s available in a C library.</p>
<p>What&#39;s truly needed is C++ language support for threads. However, the C++
standards committee needs existing practice or a good proposal as a starting
point for adding this to the standard.</p>
<p>The <b>Boost.Threads</b> library was developed to provide a C++ developer with
a portable interface for writing multi-threaded programs on numerous platforms.
There&#39;s a hope that the library can be the basis for a more detailed proposal
for the C++ standards committee to consider for inclusion in the next C++ standard.</p>
<h2><a name="primitives"></a>Rationale for the Low Level Primitives Supported
in <b>Boost.Threads</b></h2>
<p>The <b>Boost.Threads</b> library supplies a set of low level primitives for
writing multi-threaded programs, such as mutexes and condition variables. In
fact, the first release of <b>Boost.Threads</b> supports only these low level
primitives. However, computer science research has shown that use of these primitives
is difficult since there&#39;s no way to mathematically prove that a usage pattern
is correct, meaning it doesn&#39;t result in race conditions or deadlocks. There
are several algebras (such as CSP, CCS and Join calculus) that have been developed
to help write provably correct parallel processes. In order to prove the correctness
these processes must be coded using higher level abstractions. So why does <b>Boost.Threads</b>
support the lower level concepts?</p>
<p>The reason is simple: the higher level concepts need to be implemented using
at least some of the lower level concepts. So having portable lower level concepts
makes it easier to develop the higher level concepts and will allow researchers
to experiment with various techniques.</p>
<p>Beyond this theoretical application of higher level concepts, however, the
fact remains that many multi-threaded programs are written using only the lower
level concepts, so they are useful in and of themselves, even if it&#39;s hard
to prove that their usage is correct. Since many users will be familiar with
these lower level concepts but be unfamiliar with any of the higher level concepts
there&#39;s also an argument for accessibility.</p>
<h2><a name="lock_objects"></a>Rationale for the Lock Design</h2>
<p>Programmers who are used to multi-threaded programming issues will quickly
note that the Boost.Thread&#39;s design for mutex lock concepts is not <a href="definitions.html#Thread-safe">thread-safe</a>
(this is clearly documented as well). At first this may seem like a serious
design flaw. Why have a multi-threading primitive that&#39;s not thread-safe
itself?</p>
<p>A lock object is not a synchronization primitive. A lock object&#39;s sole
responsibility is to ensure that a mutex is both locked and unlocked in a manner
that won&#39;t result in the common error of locking a mutex and then forgetting
to unlock it. This means that instances of a lock object are only going to be
created, at least in theory, within block scope and won&#39;t be shared between
threads. Only the mutex objects will be created outside of block scope and/or
shared between threads. Though it&#39;s possible to create a lock object outside
of block scope and to share it between threads to do so would not be a typical
usage. Nor are there any cases when such usage would be required.</p>
<p>Lock objects must maintain some state information. In order to allow a program
to determine if a try_lock or timed_lock was successful the lock object must
retain state indicating the success or failure of the call made in its constructor.
If a lock object were to have such state and remain thread-safe it would need
to synchronize access to the state information which would result in roughly
doubling the time of most operations. Worse, since checking the state can occur
only by a call after construction we&#39;d have a race condition if the lock
object were shared between threads.</p>
<p>So, to avoid the overhead of synchronizing access to the state information
and to avoid the race condition the <b>Boost.Threads</b> library simply does
nothing to make lock objects thread-safe. Instead, sharing a lock object between
threads results in undefined behavior. Since the only proper usage of lock objects
is within block scope this isn&#39;t a problem, and so long as the lock object
is properly used there&#39;s no danger of any multi-threading issues.</p>
<h2><a name="non-copyable"></a>Rationale for Non-copyable Thread Type</h2>
<p>Programmers who are used to C libraries for multi-threaded programming are
likely to wonder why <b>Boost.Threads</b> uses a non-copyable design for <a href="thread.html">boost::thread</a>.
After all, the C thread types are copyable, and you often have a need for copying
them within user code. However, careful comparison of C designs to C++ designs
shows a flaw in this logic.</p>
<p>All C types are copyable. It is, in fact, not possible to make a non-copyable
type in C. For this reason types that represent system resources in C are often
designed to behave very similarly to a pointer to dynamic memory. There&#39;s
an API for acquiring the resource and an API for releasing the resources. For
memory we have pointers as the type and alloc/free for the acquisition and release
APIs. For files we have FILE* as the type and fopen/fclose for the acquisition
and release APIs. You can freely copy instances of the types but must manually
manage the lifetime of the actual resource through the acquisition and release
APIs.</p>
<p>C++ designs recognize that the acquisition and release APIs are error prone
and try to eliminate possible errors by acquiring the resource in the constructor
and releasing it in the destructor. The best example of such a design is the
std::iostream set of classes which can represent the same resource as the FILE*
type in C. A file is opened in the std::fstream&#39;s constructor and closed
in its destructor. However, if an iostream were copyable it could lead to a
file being closed twice, an obvious error, so the std::iostream types are noncopyable
by design. This is the same design used by boost::thread, which is a simple
and easy to understand design that&#39;s consistent with other C++ standard
types.</p>
<p>During the design of boost::thread it was pointed out that it would be possible
to allow it to be a copyable type if some form of &quot;reference management&quot;
were used, such as ref-counting or ref-lists, and many argued for a boost::thread_ref
design instead. The reasoning was that copying &quot;thread&quot; objects was
a typical need in the C libraries, and so presumably would be in the C++ libraries
as well. It was also thought that implementations could provide more efficient
reference management then wrappers (such as boost::shared_ptr) around a noncopyable
thread concept. Analysis of whether or not these arguments would hold true don&#39;t
appear to bear them out. To illustrate the analysis we&#39;ll first provide
pseudo-code illustrating the six typical usage patterns of a thread object.</p>
<h3>1. Simple creation of a thread.</h3>
<pre>
void foo()
{
create_thread(&amp;bar);
}
</pre>
<h3>2. Creation of a thread that's later joined.</h3>
<pre>
void foo()
{
@@ -159,9 +157,7 @@ void foo()
join(thread);
}
</pre>
<h3>3. Simple creation of several threads in a loop.</h3>
<h3>3. Simple creation of several threads in a loop.</h3>
<pre>
void foo()
{
@@ -169,9 +165,7 @@ void foo()
create_thread(&amp;bar);
}
</pre>
<h3>4. Creation of several threads in a loop which are later joined.</h3>
<pre>
void foo()
{
@@ -181,9 +175,7 @@ void foo()
threads[i].join();
}
</pre>
<h3>5. Creation of a thread whose ownership is passed to another object/method.</h3>
<h3>5. Creation of a thread whose ownership is passed to another object/method.</h3>
<pre>
void foo()
{
@@ -191,9 +183,7 @@ void foo()
manager.owns(thread);
}
</pre>
<h3>6. Creation of a thread whose ownership is shared between multiple objects.</h3>
<h3>6. Creation of a thread whose ownership is shared between multiple objects.</h3>
<pre>
void foo()
{
@@ -202,30 +192,24 @@ void foo()
manager2.add(thread);
}
</pre>
<p>Of these usage patterns there's only one that requires reference management (number 6).
Hopefully it's fairly obvious that this usage pattern simply won't occur as often as the
other usage patterns. So there really isn't a "typical need" for a thread concept, though
there is some need.</p>
<p>Since the need isn't typical we must use different criteria for deciding on either a
thread_ref or thread design. Possible criteria include ease of use and performance. So let's
analyze both of these carefully.</p>
<p>With ease of use we can look at existing experience. The standard C++ objects that
represent a system resource, such as std::iostream, are noncopyable, so we know that C++
programmers must at least be experienced with this design. Most C++ developers are also
used to smart pointers such as boost::shared_ptr, so we know they can at least adapt to
a thread_ref concept with little effort. So existing experience isn't going to lead us
to a choice.</p>
<p>The other thing we can look at is how difficult it is to use both types for the six usage
patterns above. If we find it overly difficult to use a concept for any of the usage patterns
there would be a good argument for choosing the other design. So we'll code all six usage
patterns using both designs.</p>
<p>Of these usage patterns there&#39;s only one that requires reference management
(number 6). Hopefully it&#39;s fairly obvious that this usage pattern simply
won&#39;t occur as often as the other usage patterns. So there really isn&#39;t
a &quot;typical need&quot; for a thread concept, though there is some need.</p>
<p>Since the need isn&#39;t typical we must use different criteria for deciding
on either a thread_ref or thread design. Possible criteria include ease of use
and performance. So let&#39;s analyze both of these carefully.</p>
<p>With ease of use we can look at existing experience. The standard C++ objects
that represent a system resource, such as std::iostream, are noncopyable, so
we know that C++ programmers must at least be experienced with this design.
Most C++ developers are also used to smart pointers such as boost::shared_ptr,
so we know they can at least adapt to a thread_ref concept with little effort.
So existing experience isn&#39;t going to lead us to a choice.</p>
<p>The other thing we can look at is how difficult it is to use both types for
the six usage patterns above. If we find it overly difficult to use a concept
for any of the usage patterns there would be a good argument for choosing the
other design. So we&#39;ll code all six usage patterns using both designs.</p>
<h3>1.</h3>
<pre>
void foo()
{
@@ -237,9 +221,7 @@ void foo()
thread_ref thrd = create_thread(&amp;bar);
}
</pre>
<h3>2.</h3>
<pre>
void foo()
{
@@ -253,9 +235,7 @@ void foo()
create_thread(&amp;bar);thrd-&gt;join();
}
</pre>
<h3>3.</h3>
<pre>
void foo()
{
@@ -269,9 +249,7 @@ void foo()
thread_ref thrd = create_thread(&amp;bar);
}
</pre>
<h3>4.</h3>
<pre>
void foo()
{
@@ -291,9 +269,7 @@ void foo()
++i)threads[i]-&gt;join();
}
</pre>
<h3>5.</h3>
<pre>
void foo()
{
@@ -307,9 +283,7 @@ void foo()
manager.owns(thrd);
}
</pre>
<h3>6.</h3>
<pre>
void foo()
{
@@ -325,15 +299,14 @@ void foo()
manager2.add(thrd);
}
</pre>
<p>This shows the usage patterns being nearly identical in complexity for both designs.
The only actual added complexity occurs because of the use of operator new in (4), (5)
and (6) and the use of std::auto_ptr and boost::shared_ptr in (4) and (6) respectively.
However, that's not really much added complexity, and C++ programmers are used to using
these idioms any way. Some may dislike the presence of operator new in user code,
but this can be eliminated by proper design of higher level concepts, such as the
boost::thread_group class that simplifies example (4) down to:</p>
<p>This shows the usage patterns being nearly identical in complexity for both
designs. The only actual added complexity occurs because of the use of operator
new in (4), (5) and (6) and the use of std::auto_ptr and boost::shared_ptr in
(4) and (6) respectively. However, that&#39;s not really much added complexity,
and C++ programmers are used to using these idioms any way. Some may dislike
the presence of operator new in user code, but this can be eliminated by proper
design of higher level concepts, such as the boost::thread_group class that
simplifies example (4) down to:</p>
<pre>
void foo()
{
@@ -343,89 +316,83 @@ void foo()
threads.join_all();
}
</pre>
<p>So ease of use is really a wash and not much help in picking a design.</p>
<p>So what about performance? If you look at the above code examples we can analyze
the theoretical impact to performance that both designs have. For (1) we can see that
platforms that don't have a ref-counted native thread type (POSIX, for instance) will
be impacted by a thread_ref design. Even if the native thread type is ref-counted there
may be an impact if more state information has to be maintained for concepts foreign
to the native API, such as clean up stacks for Win32 implementations. For (2) the
performance impact will be identical to (1). The same for (3). For (4) things get a
little more interesting and we find that theoretically at least the thread_ref may
perform faster since the thread design requires dynamic memory allocation/deallocation.
However, in practice there may be dynamic allocation for the thread_ref design as well,
it will just be hidden from the user. As long as the implementation has to do dynamic
allocations the thread_ref loses again because of the reference management. For (5)
we see the same impact as we do for (4). For (6) we still have a possible impact
to the thread design because of dynamic allocation but thread_ref no longer suffers
because of it's reference management, and in fact, theoretically at least, the thread_ref
may do a better job of managing the references. All of this indicates that thread wins
for (1), (2) and (3), with (4) and (5) the winner depends on the implementation and the platform
but the thread design probably has a better chance, and with (6) it will again
depend on the implementation and platform but this time we favor thread_ref slightly.
Given all of this it's a narrow margin, but the thread design prevails.</p>
<p>Given this analysis, and the fact that noncopyable objects for system resources are
the normal designs that C++ programmers are used to dealing with, the Boost.Threads
library has gone with a noncopyable design.</p>
<h2>Rationale for not providing <i><a name="Events">Event</a> Variables</i></h2>
<p><i>Event variables </i>are simply far too error-prone.&nbsp; <a href="condition.html">Condition
variables</a> are a much safer alternative.</p>
<p>[Note that Graphical User Interface <i>events</i> are a different concept,
and are not what is being discussed here.]</p>
<p>Event variables were one of the first synchronization primitives. They are
still used today, for example, in the native Windows multithreading API.</p>
<p>Yet both respected computer science researchers and experienced
multithreading practitioners believe event variables are so inherently
error-prone that they should never be used, and thus should not be part of a
multithreading library.</p>
<p>Per Brinch Hansen <a href="bibliography.html#Brinch-Hansen-73">[Brinch Hansen
73]</a> analyzed event variables in some detail, pointing out [emphasis his]
that &quot;<i>event operations force the programmer to be aware of the relative
speeds of the sending and receiving processes</i>&quot;. His summary:</p>
<blockquote>
<p>We must therefore conclude that event variables of the previous type are
impractical for system design. <i>The effect of an interaction between two
processes must be independent of the speed at which it is carried out.</i></p>
<p>So what about performance? If you look at the above code examples we can analyze
the theoretical impact to performance that both designs have. For (1) we can
see that platforms that don&#39;t have a ref-counted native thread type (POSIX,
for instance) will be impacted by a thread_ref design. Even if the native thread
type is ref-counted there may be an impact if more state information has to
be maintained for concepts foreign to the native API, such as clean up stacks
for Win32 implementations. For (2) the performance impact will be identical
to (1). The same for (3). For (4) things get a little more interesting and we
find that theoretically at least the thread_ref may perform faster since the
thread design requires dynamic memory allocation/deallocation. However, in practice
there may be dynamic allocation for the thread_ref design as well, it will just
be hidden from the user. As long as the implementation has to do dynamic allocations
the thread_ref loses again because of the reference management. For (5) we see
the same impact as we do for (4). For (6) we still have a possible impact to
the thread design because of dynamic allocation but thread_ref no longer suffers
because of it&#39;s reference management, and in fact, theoretically at least,
the thread_ref may do a better job of managing the references. All of this indicates
that thread wins for (1), (2) and (3), with (4) and (5) the winner depends on
the implementation and the platform but the thread design probably has a better
chance, and with (6) it will again depend on the implementation and platform
but this time we favor thread_ref slightly. Given all of this it&#39;s a narrow
margin, but the thread design prevails.</p>
<p>Given this analysis, and the fact that noncopyable objects for system resources
are the normal designs that C++ programmers are used to dealing with, the <b>Boost.Threads</b>
library has gone with a noncopyable design.</p>
<h2><a name="events"></a>Rationale for not providing <i>Event Variables</i></h2>
<p><i>Event variables</i> are simply far too error-prone. <a href=
"condition.html">Condition variables</a> are a much safer alternative.</p>
<p>[Note that Graphical User Interface <i>events</i> are a different concept,
and are not what is being discussed here.]</p>
<p>Event variables were one of the first synchronization primitives. They are
still used today, for example, in the native Windows multithreading API.</p>
<p>Yet both respected computer science researchers and experienced multithreading
practitioners believe event variables are so inherently error-prone that they
should never be used, and thus should not be part of a multithreading library.</p>
<p>Per Brinch Hansen <a href="bibliography.html#Brinch-Hansen-73"> [Brinch Hansen
73]</a> analyzed event variables in some detail, pointing out [emphasis his]
that &quot;<i>event operations force the programmer to be aware of the relative
speeds of the sending and receiving processes</i>&quot;. His summary:</p>
<blockquote>
<p>We must therefore conclude that event variables of the previous type are
impractical for system design. <i>The effect of an interaction between two
processes must be independent of the speed at which it is carried out.</i></p>
</blockquote>
<p>Experienced programmers using the Windows platform today
report that event variables are a continuing source of errors, even after previous
bad experiences caused them to be very careful in their use of event
variables.&nbsp; Overt problems can be avoided, for example, by teaming the
event variable with a mutex, but that may just convert a <a href="definitions.html#Race condition">race
condition</a> into another problem, such as excessive resource use. One of the most
distressing aspects of the experience reports is the claim that many defects are
latent.&nbsp; That is, the programs appear to work correctly, but contain
hidden timing dependencies which will cause them to fail when environmental
factors or usage patterns change, altering relative thread timings.</p>
<p>The decision to exclude event variables from Boost.Threads has been
surprising to some Windows programmers.&nbsp; They have written programs which
work using event variables, and wonder what the problem is.&nbsp; It seems
similar to the &quot;goto considered harmful&quot; controversy of 30 years ago.
It isn't that events, like gotos, can't be made to work, but rather that
virtually all programs using alternatives will be easier to write, debug,
read, maintain, and be less likely to contain latent defects.</p>
<p>Experienced programmers using the Windows platform today report that event
variables are a continuing source of errors, even after previous bad experiences
caused them to be very careful in their use of event variables. Overt problems
can be avoided, for example, by teaming the event variable with a mutex, but
that may just convert a <a href=
"definitions.html#Race condition">race condition</a> into another problem,
such as excessive resource use. One of the most distressing aspects of the experience
reports is the claim that many defects are latent. That is, the programs appear
to work correctly, but contain hidden timing dependencies which will cause them
to fail when environmental factors or usage patterns change, altering relative
thread timings.</p>
<p>The decision to exclude event variables from <b>Boost.Threads</b> has been
surprising to some Windows programmers. They have written programs which work
using event variables, and wonder what the problem is. It seems similar to the
&quot;goto considered harmful&quot; controversy of 30 years ago. It isn&#39;t
that events, like gotos, can&#39;t be made to work, but rather that virtually
all programs using alternatives will be easier to write, debug, read, maintain,
and be less likely to contain latent defects.</p>
<p>[Rationale provided by Beman Dawes]</p>
<hr>
<p>Revised <!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->01 October, 2001<!--webbot bot="Timestamp" endspan i-checksum="38291" -->
<p>Revised
<!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->
05 November, 2001
<!--webbot bot="Timestamp" endspan i-checksum="39359" -->
</p>
<p><i>© Copyright <A href="mailto:williamkempf@hotmail.com">William E. Kempf</A>
2001 all rights reserved.</i></p>
<p><i>&copy; Copyright <a href="mailto:wekempf@cox.net">William E. Kempf</a> 2001-2002.
All Rights Reserved.</i></p>
<p>Permission to use, copy, modify, distribute and sell this software and its
documentation for any purpose is hereby granted without fee, provided that the
above copyright notice appear in all copies and that both that copyright notice
and this permission notice appear in supporting documentation. William E. Kempf
makes no representations about the suitability of this software for any purpose.
It is provided &quot;as is&quot; without express or implied warranty.</p>
</body>
</html>

View File

@@ -1,126 +1,173 @@
<html>
<head>
<meta http-equiv="Content-Type" content=
"text/html; charset=iso-8859-1">
<meta name="keywords" content="threads, BTL, thread library, C++">
<link rel="stylesheet" type="text/css" href="styles.css">
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<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<meta name="keywords" content="threads, BTL, thread library, C++">
<link rel="stylesheet" type="text/css" href="styles.css">
<title>Boost.Threads, recursive_mutex</title>
</head>
<title>Boost.Threads, recursive_mutex</title>
</head>
<body bgcolor="#FFFFFF" link="#0000FF" vlink="#800080">
<body bgcolor="#FFFFFF" link="#0000FF" vlink="#800080">
<table summary="header" border="0" cellpadding="7" cellspacing="0" width="100%">
<tr>
<td valign="top" width="300">
<h3><img src="../../../c++boost.gif" alt="C++ Boost" width=
"277" height="86"></h3>
</td>
<table border="0" cellpadding="7" cellspacing="0" width="100%">
<tr>
<td valign="top" width="300">
<h3><img src="../../../c++boost.gif" alt="C++ Boost" width="277" height="86"></h3>
</td>
<td valign="top">
<h1 align="center">Boost.Threads</h1>
<h2 align="center">recursive_mutex<br>
recursive_try_mutex<br>
recursive_timed_mutex</h2>
</td>
</tr>
</table>
<td valign="top">
<h1 align="center">Boost.Threads</h1>
<hr>
<h2 align="center">recursive_mutex<br>
recursive_try_mutex<br>
recursive_timed_mutex</h2>
</td>
</tr>
</table>
<hr>
<p><a href="#Introduction">Introduction</a><br>
<a href="#Header">Header</a><br>
<a href="#recursive_mutex Synopsis">Class recursive_mutex Synopsis</a><br>
<a href="#recursive_mutex Members">Class recursive_mutex Members</a><br>
<a href="#recursive_try_mutex Synopsis">Class recursive_try_mutex Synopsis</a><br>
<a href="#recursive_try_mutex Members">Class recursive_try_mutex Members</a><br>
<a href="#recursive_timed_mutex Synopsis">Class recursive_timed_mutex Synopsis</a><br>
<a href="#recursive_timed_mutex Members">Class recursive_timed_mutex Members</a><br>
<a href="#Example">Example</a></p>
<p><a href="#Introduction">Introduction</a><br>
<a href="#Header">Header</a><br>
<a href="#recursive_mutex Synopsis">Class recursive_mutex
Synopsis</a><br>
<a href="#recursive_mutex Members">Class recursive_mutex
Members</a><br>
<a href="#recursive_try_mutex Synopsis">Class recursive_try_mutex
Synopsis</a><br>
<a href="#recursive_try_mutex Members">Class recursive_try_mutex
Members</a><br>
<a href="#recursive_timed_mutex Synopsis">Class recursive_timed_mutex
Synopsis</a><br>
<a href="#recursive_timed_mutex Members">Class recursive_timed_mutex
Members</a><br>
<a href="#Example">Example</a></p>
<h2><a name="Introduction">Introduction</a></h2>
<h2><a name="Introduction">Introduction</a></h2>
<p>The <code>recursive_mutex</code>, <code>recursive_try_mutex</code> and
<code>recursive_timed_mutex</code> classes define full featured models of the
<a href="mutex_concept.html#Mutex">Mutex</a>,
<a href="mutex_concept.html#TryMutex">TryMutex</a> and
<a href="mutex_concept.html#TimedMutex">TimedMutex</a> concepts with recursive locking
semantics. These types should be used to synchronize access to shared resources
when recursive locking by a single thread is likely to occur. A good example for this
is when a class supplies "internal synchronization" to ensure
<a href="definitions.html#Thread-safe">thread-safety</a> and a function of the class
may have to call other functions of the class which also attempt to lock the mutex.
For recursive locking mechanics, see <a href="mutex.html">mutexes</a>.
<p>The <code>recursive_mutex</code>, <code>recursive_try_mutex</code>
and <code>recursive_timed_mutex</code> classes define full featured
models of the <a href="mutex_concept.html#Mutex">Mutex</a>, <a href=
"mutex_concept.html#TryMutex">TryMutex</a> and <a href=
"mutex_concept.html#TimedMutex">TimedMutex</a> concepts with recursive
locking semantics. These types should be used to synchronize access to
shared resources when recursive locking by a single thread is likely to
occur. A good example for this is when a class supplies &quot;internal
synchronization&quot; to ensure <a href="definitions.html#Thread-safe">
thread-safety</a> and a function of the class may have to call other
functions of the class which also attempt to lock the mutex. For
recursive locking mechanics, see <a href="mutex.html">mutexes</a>.</p>
<p>Each class supplies one or more typedefs for lock types which model matching
lock concepts. For the best possible performance you should use the mutex class that
supports the minimum set of lock types that you need.</p>
<p>Each class supplies one or more typedefs for lock types which model
matching lock concepts. For the best possible performance you should
use the mutex class that supports the minimum set of lock types that
you need.</p>
<table border="1" cellpadding="5">
<tr>
<td><b>Mutex Class</b></td>
<td><b>Lock name</b></td>
<td><b>Implementation defined Lock Type</b></td>
<td><b>Lock Concept</b></td>
</tr>
<tr>
<td valign="top"><a href="#recursive_mutex Synopsis"><code>recursive_mutex</code></a></td>
<td valign="middle"><code>scoped_lock</code></td>
<td valign="middle"><a href="scoped_lock.html"><code>detail::thread::scoped_lock&lt;recursive_mutex&gt;</code></a></td>
<td valign="middle"><a href="lock_concept.html#ScopedLock">ScopedLock</a></td>
</tr>
<tr>
<td valign="top"><code><a href="#recursive_try_mutex Synopsis">recursive_try_mutex</a></code></td>
<td valign="middle"><code>scoped_lock<br>
scoped_try_lock</code></td>
<td valign="middle"><a href="scoped_lock.html"><code>detail::thread::scoped_lock&lt;recursive_try_mutex&gt;<br>
</code></a><code><a href="scoped_try_lock.html">detail::thread::scoped_try_lock&lt;recursive_try_mutex&gt;</a></code></td>
<td valign="middle"><a href="lock_concept.html#ScopedLock">ScopedLock</a><br>
<a href="lock_concept.html#ScopedTryLock">ScopedTryLock</a></td>
</tr>
<tr>
<td valign="top"><code><a href="#recursive_timed_mutex Synopsis">recursive_timed_mutex</a></code> </td>
<td valign="middle"><code>scoped_lock<br>
scoped_try_lock<br>
scoped_timed_lock</code></td>
<td valign="middle"><a href="scoped_lock.html"><code>detail::thread::scoped_lock&lt;recursive_timed_mutex&gt;</code></a><br>
<a href="scoped_try_lock.html"><code>detail::thread::scoped_try_lock&lt;recursive_timed_mutex&gt;</code></a><br>
<a href="scoped_timed_lock.html"><code>detail::thread::scoped_timed_lock&lt;recursive_timed_mutex&gt;</code></a></td>
<td valign="middle"><a href="lock_concept.html#ScopedLock">ScopedLock</a><br>
<a href="lock_concept.html#ScopedTryLock">ScopedTryLock</a><br>
<a href="lock_concept.html#ScopedTimedLock">ScopedTimedLock</a></td>
</tr>
</table>
<table summary="lock types" border="1" cellpadding="5">
<tr>
<td><b>Mutex Class</b></td>
<p>The <code>recursive_mutex</code>, <code>recursive_try_mutex</code> and
<code>recursive_timed_mutex</code> employ a <code>Recursive</code>
<a href="mutex_concept.html#LockingStrategies">locking strategy</a>, so attempts to
recursively lock them succeed and an internal "lock count" is maintained. Attempts
to unlock them by a thread that does not own a lock on them will result in a
<a href="lock_error.html">lock_error</a> exception being thrown.</p>
<td><b>Lock name</b></td>
<p>The <code>recursive_mutex</code>, <code>recursive_try_mutex</code> and
<code>recursive_timed_mutex</code> leave the
<a href="mutex_concept.html#SchedulingPolicies">scheduling policy</a> as
<code>Unspecified</code>. Programmers should assume that threads waiting for a lock on
objects of these types acquire the lock in a random order, even though the specific
behavior for a given platform may be different.</p>
<td><b>Implementation defined Lock Type</b></td>
<h2><a name="Header">Header</a></h2>
<td><b>Lock Concept</b></td>
</tr>
<tr>
<td valign="top"><a href="#recursive_mutex Synopsis"><code>
recursive_mutex</code></a></td>
<td valign="middle"><code>scoped_lock</code></td>
<td valign="middle"><a href="scoped_lock.html"><code>
detail::thread::scoped_lock&lt;recursive_mutex&gt;</code></a></td>
<td valign="middle"><a href="lock_concept.html#ScopedLock">
ScopedLock</a></td>
</tr>
<tr>
<td valign="top"><code><a href="#recursive_try_mutex Synopsis">
recursive_try_mutex</a></code></td>
<td valign="middle"><code>scoped_lock<br>
scoped_try_lock</code></td>
<td valign="middle"><a href="scoped_lock.html"><code>
detail::thread::scoped_lock&lt;recursive_try_mutex&gt;<br>
</code></a> <code><a href="scoped_try_lock.html">
detail::thread::scoped_try_lock&lt;recursive_try_mutex&gt;</a></code></td>
<td valign="middle"><a href="lock_concept.html#ScopedLock">
ScopedLock</a><br>
<a href="lock_concept.html#ScopedTryLock">
ScopedTryLock</a></td>
</tr>
<tr>
<td valign="top"><code><a href=
"#recursive_timed_mutex Synopsis">
recursive_timed_mutex</a></code> </td>
<td valign="middle"><code>scoped_lock<br>
scoped_try_lock<br>
scoped_timed_lock</code></td>
<td valign="middle"><a href="scoped_lock.html"><code>
detail::thread::scoped_lock&lt;recursive_timed_mutex&gt;</code></a><br>
<a href="scoped_try_lock.html"><code>
detail::thread::scoped_try_lock&lt;recursive_timed_mutex&gt;</code></a><br>
<a href="scoped_timed_lock.html"><code>
detail::thread::scoped_timed_lock&lt;recursive_timed_mutex&gt;</code></a></td>
<td valign="middle"><a href="lock_concept.html#ScopedLock">
ScopedLock</a><br>
<a href="lock_concept.html#ScopedTryLock">
ScopedTryLock</a><br>
<a href="lock_concept.html#ScopedTimedLock">
ScopedTimedLock</a></td>
</tr>
</table>
<p>The <code>recursive_mutex</code>, <code>recursive_try_mutex</code>
and <code>recursive_timed_mutex</code> employ a <code>Recursive</code>
<a href="mutex_concept.html#LockingStrategies">locking strategy</a>, so
attempts to recursively lock them succeed and an internal &quot;lock
count&quot; is maintained. Attempts to unlock them by a thread that
does not own a lock on them will result in a <a href="lock_error.html">
lock_error</a> exception being thrown.</p>
<p>The <code>recursive_mutex</code>, <code>recursive_try_mutex</code>
and <code>recursive_timed_mutex</code> leave the <a href=
"mutex_concept.html#SchedulingPolicies">scheduling policy</a> as <code>
Unspecified</code>. Programmers should assume that threads waiting for
a lock on objects of these types acquire the lock in a random order,
even though the specific behavior for a given platform may be
different.</p>
<h2><a name="Header">Header</a></h2>
<pre>
#include <a href="../../../boost/thread/recursive_mutex.hpp">&lt;boost/thread/recursive_mutex.hpp&gt;</a>
#include <a href=
"../../../boost/thread/recursive_mutex.hpp">&lt;boost/thread/recursive_mutex.hpp&gt;</a>
</pre>
<h2>Class <a name="recursive_mutex Synopsis"> recursive_mutex Synopsis</a></h2>
<hr>
<h2>Class <a name="recursive_mutex Synopsis">recursive_mutex
Synopsis</a></h2>
<hr>
<pre>
namespace boost
{
class recursive_mutex : private <a href="../../utility/utility.htm">boost::noncopyable</a> // Exposition only.
// Class recursive_mutex meets the <a href="overview.html#NonCopyable">NonCopyable</a> requirement.
class recursive_mutex : private <a href=
"../../utility/utility.htm">boost::noncopyable</a> // Exposition only.
// Class recursive_mutex meets the <a href=
"overview.html#NonCopyable">NonCopyable</a> requirement.
{
public:
typedef <i>[implementation defined; see <a href="#Introduction">Introduction</a>]</i> scoped_lock;
typedef <i>[implementation defined; see <a href=
"#Introduction">Introduction</a>]</i> scoped_lock;
recursive_mutex();
~recursive_mutex();
@@ -128,48 +175,47 @@ namespace boost
}
</pre>
<h2>Class <a name="recursive_mutex Members">recursive_mutex Members</a></h2>
<hr>
<h3>Constructor</h3>
<h2>Class <a name="recursive_mutex Members">recursive_mutex
Members</a></h2>
<hr>
<h3>Constructor</h3>
<pre>
recursive_mutex();
</pre>
<p><b>Postconditions: </b><code>*this</code> is in the unlocked state.</p>
<hr>
<h3>Destructor</h3>
<p><b>Postconditions:</b> <code>*this</code> is in the unlocked
state.</p>
<hr>
<h3>Destructor</h3>
<pre>
~recursive_mutex();
</pre>
<p><b>Requires:</b> <code>*this</code> is in the unlocked state.</p>
<p><b>Requires:</b> <code>*this</code> is in the unlocked state.</p>
<p><b>Effects:</b> Destroys <code>*this</code>.</p>
<p><b>Effects:</b> Destroys <code>*this</code>.</p>
<p><b>Dangers:</b> Destruction of a locked mutex is a serious programming error
resulting in undefined behavior such as a program crash..</p>
<hr>
<h2>
Class <a name="recursive_try_mutex Synopsis">recursive_try_mutex Synopsis</a>
</h2>
<p><b>Dangers:</b> Destruction of a locked mutex is a serious
programming error resulting in undefined behavior such as a program
crash..</p>
<hr>
<h2>Class <a name="recursive_try_mutex Synopsis">recursive_try_mutex
Synopsis</a></h2>
<pre>
namespace boost
{
class recursive_try_mutex : private boost::noncopyable // Exposition only.
// Class recursive_try_mutex meets the <a href="overview.html#NonCopyable">NonCopyable</a> requirement.
// Class recursive_try_mutex meets the <a href=
"overview.html#NonCopyable">NonCopyable</a> requirement.
{
public:
typedef <i>[implementation defined; see <a href="#Introduction">Introduction</a>]</i> scoped_lock;
typedef <i>[implementation defined; see <a href="#Introduction">Introduction</a>]</i> scoped_try_lock;
typedef <i>[implementation defined; see <a href=
"#Introduction">Introduction</a>]</i> scoped_lock;
typedef <i>[implementation defined; see <a href=
"#Introduction">Introduction</a>]</i> scoped_try_lock;
recursive_try_mutex();
~recursive_try_mutex();
@@ -177,49 +223,49 @@ namespace boost
}
</pre>
<h2>Class <a name="recursive_try_mutex Members">recursive_try_mutex Members</a></h2>
<hr>
<h3>Constructor</h3>
<h2>Class <a name="recursive_try_mutex Members">recursive_try_mutex
Members</a></h2>
<hr>
<h3>Constructor</h3>
<pre>
recursive_try_mutex();
</pre>
<p><b>Postconditions: </b><code>*this</code> is in the unlocked state.</p>
<hr>
<h3>Destructor</h3>
<p><b>Postconditions:</b> <code>*this</code> is in the unlocked
state.</p>
<hr>
<h3>Destructor</h3>
<pre>
~recursive_try_mutex();
</pre>
<p><b>Requires:</b> <code>*this</code> is in the unlocked state.</p>
<p><b>Requires:</b> <code>*this</code> is in the unlocked state.</p>
<p><b>Effects:</b> Destroys <code>*this</code>.</p>
<p><b>Effects:</b> Destroys <code>*this</code>.</p>
<p><b>Dangers:</b> Destruction of a locked mutex is a serious programming error
resulting in undefined behavior such as a program crash..</p>
<hr>
<h2>
Class <a name="recursive_timed_mutex Synopsis">recursive_timed_mutex Synopsis</a>
</h2>
<p><b>Dangers:</b> Destruction of a locked mutex is a serious
programming error resulting in undefined behavior such as a program
crash..</p>
<hr>
<h2>Class <a name="recursive_timed_mutex Synopsis">
recursive_timed_mutex Synopsis</a></h2>
<pre>
namespace boost
{
class recursive_timed_mutex : private boost::noncopyable // Exposition only.
// Class recursive_timed_mutex meets the <a href="overview.html#NonCopyable">NonCopyable</a> requirement.
// Class recursive_timed_mutex meets the <a href=
"overview.html#NonCopyable">NonCopyable</a> requirement.
{
public:
typedef <i>[implementation defined; see <a href="#Introduction">Introduction</a>]</i> scoped_lock;
typedef <i>[implementation defined; see <a href="#Introduction">Introduction</a>]</i> scoped_try_lock;
typedef <i>[implementation defined; see <a href="#Introduction">Introduction</a>]</i> scoped_timed_lock;
typedef <i>[implementation defined; see <a href=
"#Introduction">Introduction</a>]</i> scoped_lock;
typedef <i>[implementation defined; see <a href=
"#Introduction">Introduction</a>]</i> scoped_try_lock;
typedef <i>[implementation defined; see <a href=
"#Introduction">Introduction</a>]</i> scoped_timed_lock;
recursive_timed_mutex();
~recursive_timed_mutex();
@@ -227,42 +273,39 @@ namespace boost
}
</pre>
<h2>
Class <a name="recursive_timed_mutex Members">recursive_timed_mutex Members</a>
</h2>
<hr>
<h3>Constructor</h3>
<h2>Class <a name="recursive_timed_mutex Members">recursive_timed_mutex
Members</a></h2>
<hr>
<h3>Constructor</h3>
<pre>
recursive_timed_mutex();
</pre>
<p><b>Postconditions: </b><code>*this</code> is in the unlocked state.</p>
<hr>
<h3>Destructor</h3>
<p><b>Postconditions:</b> <code>*this</code> is in the unlocked
state.</p>
<hr>
<h3>Destructor</h3>
<pre>
~recursive_timed_mutex();
</pre>
<p><b>Requires:</b> <code>*this</code> is in the unlocked state.</p>
<p><b>Requires:</b> <code>*this</code> is in the unlocked state.</p>
<p><b>Effects:</b> Destroys <code>*this</code>.</p>
<p><b>Effects:</b> Destroys <code>*this</code>.</p>
<p><b>Dangers:</b> Destruction of a locked mutex is a serious programming error
resulting in undefined behavior such as a program crash..</p>
<hr>
<h2><a name="Example">Example</a> Usage</h2>
<p><b>Dangers:</b> Destruction of a locked mutex is a serious
programming error resulting in undefined behavior such as a program
crash..</p>
<hr>
<h2><a name="Example">Example</a> Usage</h2>
<pre>
#include <a href="../../../boost/thread/recursive_mutex.hpp">&lt;boost/thread/recursive_mutex.hpp&gt;</a>
#include <a href="../../../boost/thread/thread.hpp">&lt;boost/thread/thread.hpp&gt;</a>
#include <a href=
"../../../boost/thread/recursive_mutex.hpp">&lt;boost/thread/recursive_mutex.hpp&gt;</a>
#include <a href=
"../../../boost/thread/thread.hpp">&lt;boost/thread/thread.hpp&gt;</a>
#include &lt;iostream&gt;
class counter
@@ -306,22 +349,20 @@ int main(int, char*[])
}
</pre>
<p>The output is:</p>
<p>The output is:</p>
<pre>
count == 1
count == 2
count == 3
count == 4
</pre>
<hr>
<hr>
<p>Revised
<!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->05 November, 2001<!--webbot bot="Timestamp" endspan i-checksum="39359" --></p>
<p>Revised <!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->01 October, 2001<!--webbot bot="Timestamp" endspan i-checksum="38291" -->
</p>
<p><i>© Copyright <a href="mailto:williamkempf@hotmail.com">William E. Kempf</a>
2001 all rights reserved.</i></p>
</body>
<p><i>&copy; Copyright <a href="mailto:williamkempf@hotmail.com">
William E. Kempf</a> 2001 all rights reserved.</i></p>
</body>
</html>

View File

@@ -124,7 +124,7 @@ int test_main(int, char*[])
<hr>
<p>Revised <!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->01 October, 2001<!--webbot bot="Timestamp" endspan i-checksum="38291" -->
<p>Revised <!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->05 November, 2001<!--webbot bot="Timestamp" endspan i-checksum="39359" -->
</p>
<p><i>© Copyright <a href="mailto:williamkempf@hotmail.com">William E. Kempf</a>

View File

@@ -1,80 +1,90 @@
<html>
<head>
<meta http-equiv="Content-Type" content=
"text/html; charset=iso-8859-1">
<meta name="keywords" content="threads, BTL, thread library, C++">
<link rel="stylesheet" type="text/css" href="styles.css">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<meta name="keywords" content="threads, BTL, thread library, C++">
<link rel="stylesheet" type="text/css" href="styles.css">
<title>Boost.Threads, scoped_lock</title>
</head>
<title>Boost.Threads, scoped_lock</title>
</head>
<body bgcolor="#FFFFFF" link="#0000FF" vlink="#800080">
<body bgcolor="#FFFFFF" link="#0000FF" vlink="#800080">
<table summary="header" border="0" cellpadding="7" cellspacing="0"
width="100%">
<tr>
<td valign="top" width="300">
<h3><img src="../../../c++boost.gif" alt="C++ Boost" width=
"277" height="86"></h3>
</td>
<table border="0" cellpadding="7" cellspacing="0" width="100%">
<tr>
<td valign="top" width="300">
<h3><img src="../../../c++boost.gif" alt="C++ Boost" width="277" height="86"></h3>
</td>
<td valign="top">
<h1 align="center">Boost.Threads</h1>
<h2 align="center">scoped_lock</h2>
</td>
</tr>
</table>
<td valign="top">
<h1 align="center">Boost.Threads</h1>
<hr>
<h2 align="center">scoped_lock</h2>
</td>
</tr>
</table>
<hr>
<p><a href="#Introduction">Introduction</a><br>
<a href="#Header">Header</a><br>
<a href="#Synopsis">Synopsis</a><br>
<a href="#Members">Members</a><br>
<a href="#Example">Example</a></p>
<p><a href="#Introduction">Introduction</a><br>
<a href="#Header">Header</a><br>
<a href="#Synopsis">Synopsis</a><br>
<a href="#Members">Members</a><br>
<a href="#Example">Example</a></p>
<h2><a name="Introduction">Introduction</a></h2>
<h2><a name="Introduction">Introduction</a></h2>
<p>This class template defines a generic lock type which meets the
<a href="lock_concept.html#ScopedLock">ScopedLock</a> requirements. The
<a href="mutex.html">mutex</a>, <a href="mutex.html">try_mutex</a>,
<a href="mutex.html">timed_mutex</a>, <a href="recursive_mutex.html">recursive_mutex</a>,
<a href="recursive_mutex.html">recursive_try_mutex</a> and
<a href="recursive_mutex.html">recursive_timed_mutex</a> classes all use this template
to define their <code>scoped_lock</code> types.</p>
<p>This class template defines a generic lock type which meets the <a
href="lock_concept.html#ScopedLock">ScopedLock</a> requirements. The <a
href="mutex.html">mutex</a>, <a href="mutex.html">try_mutex</a>, <a
href="mutex.html">timed_mutex</a>, <a href="recursive_mutex.html">
recursive_mutex</a>, <a href="recursive_mutex.html">
recursive_try_mutex</a> and <a href="recursive_mutex.html">
recursive_timed_mutex</a> classes all use this template to define their
<code>scoped_lock</code> types.</p>
<p>Like all the <b>Boost.Threads</b> <a href="lock_concept.html">lock models</a>,
<code>scoped_lock</code> objects are meant to be short-lived. Objects of the class
are not <a href="definitions.html#thread-safe">thread-safe</a>, and so should not be
shared between threads.</p>
<p>Like all the <b>Boost.Threads</b> <a href="lock_concept.html">lock
models</a>, <code>scoped_lock</code> objects are meant to be
short-lived. Objects of the class are not <a href=
"definitions.html#thread-safe">thread-safe</a>, and so should not be
shared between threads.</p>
<p>Class <code> scoped_lock</code> follows the &quot;resource acquisition is
initialization&quot; idiom <a href="bibliography.html#Stroustrup-00">[Stroustrup
00 14.4.1]</a> and is a realization of the &quot;Scoped Locking Pattern&quot;
<a href="bibliography.html#Schmidt-00">[Schmidt-00]</a>. Thus the usage is to let the
constructor do the locking, and then let the destructor do the unlocking automatically at
the end of the enclosing scope. The lock() and unlock() members are usually not
explicitly called, but are provided to allow for complex overlapping locks of multiple
mutexes.</p>
<p>Class <code>scoped_lock</code> follows the &quot;resource
acquisition is initialization&quot; idiom <a href=
"bibliography.html#Stroustrup-00">[Stroustrup 00 14.4.1]</a> and is a
realization of the &quot;Scoped Locking Pattern&quot; <a href=
"bibliography.html#Schmidt-00">[Schmidt-00]</a>. Thus the usage is to
let the constructor do the locking, and then let the destructor do the
unlocking automatically at the end of the enclosing scope. The lock()
and unlock() members are usually not explicitly called, but are
provided to allow for complex overlapping locks of multiple
mutexes.</p>
<p>The type used to instantiate the class must meet the
<a href="mutex_concept.html#Mutex">Mutex</a> requirements.</p>
<p>The type used to instantiate the class must meet the <a href=
"mutex_concept.html#Mutex">Mutex</a> requirements.</p>
<p>Although this class is an implementation detail, it is publicly documented here because
of its importance.</p>
<h2><a name="Header">Header</a></h2>
<p>Although this class is an implementation detail, it is publicly
documented here because of its importance.</p>
<h2><a name="Header">Header</a></h2>
<pre>
#include <a href="../../../boost/thread/detail/lock.hpp">&lt;boost/thread/detail/lock.hpp&gt;</a>
#include <a href=
"../../../boost/thread/detail/lock.hpp">&lt;boost/thread/detail/lock.hpp&gt;</a>
<i>This header is usually not included directly by programmers
because it is supplied by <a href="../../../boost/thread/mutex.hpp">&lt;boost/thread/mutex.hpp&gt;</a> or
<a href="../../../boost/thread/recursive_mutex.hpp">&lt;boost/thread/recursive_mutex.hpp&gt;</a></i>
because it is supplied by <a href=
"../../../boost/thread/mutex.hpp">&lt;boost/thread/mutex.hpp&gt;</a> or
<a href=
"../../../boost/thread/recursive_mutex.hpp">&lt;boost/thread/recursive_mutex.hpp&gt;</a></i>
</pre>
<h2><a name="Synopsis">Synopsis</a></h2>
<h2><a name="Synopsis">Synopsis</a></h2>
<pre>
namespace boost { namespace detail { namespace thread {
template &lt;typename Mutex&gt;
class scoped_lock : private <a href="../../utility/utility.htm#Class noncopyable">boost::noncopyable</a> // Exposition only.
// Class scoped_lock meets the <a href="overview.html#NonCopyable">NonCopyable</a> requirement.
class scoped_lock : private <a href=
"../../utility/utility.htm#Class noncopyable">boost::noncopyable</a> // Exposition only.
// Class scoped_lock meets the <a href=
"overview.html#NonCopyable">NonCopyable</a> requirement.
{
public:
typedef Mutex mutex_type;
@@ -93,121 +103,125 @@ namespace boost { namespace detail { namespace thread {
} // namespace boost
</pre>
<h2><a name="Members">Members</a></h2>
<hr>
<h3>Constructor</h3>
<h2><a name="Members">Members</a></h2>
<hr>
<h3>Constructor</h3>
<pre>
explicit scoped_lock(Mutex&amp; mx, bool initially_locked=true);
</pre>
<p><b>Effects:</b> Associates mutex <code>mx</code> with <code>*this</code>.
If <code>initially_locked</code> is <code>true,</code> calls <code>lock()</code>.</p>
<hr>
<h3>Destructor</h3>
<p><b>Effects:</b> Associates mutex <code>mx</code> with <code>
*this</code>. If <code>initially_locked</code> is <code>true,</code>
calls <code>lock()</code>.</p>
<hr>
<h3>Destructor</h3>
<pre>
~scoped_lock();
</pre>
<p><b>Effects:</b> If <code> locked()</code>, calls <code>unlock()</code>. Destroys
<code>*this</code>.</p>
<hr>
<h3>lock</h3>
<p><b>Effects:</b> If <code>locked()</code>, calls <code>
unlock()</code>. Destroys <code>*this</code>.</p>
<hr>
<h3>lock</h3>
<pre>
void lock();
</pre>
<p><b>Effects:</b> If the associated mutex is already locked by another lock in the
current thread, the effects depend on the locking strategy of the associated mutex, as
shown in the following table:</p>
<p><b>Effects:</b> If the associated mutex is already locked by another
lock in the current thread, the effects depend on the locking strategy
of the associated mutex, as shown in the following table:</p>
<table border="1" cellpadding="5">
<tr>
<td><i><a href="mutex_concept.html#LockingStrategies">Locking Strategy</a><br>
of associated mutex</i></td>
<td><i>Effect if associated mutex is already locked by the current thread</i></td>
</tr>
<tr>
<td>Recursive</td>
<td>As if an additional lock were added to the mutex.</td>
</tr>
<tr>
<td>Checked</td>
<td>Throws <a href="lock_error.html">lock_error</a>.</td>
</tr>
<tr>
<td>Unchecked</td>
<td>Undefined behavior [<a href="bibliography.html#ISO">ISO</a> 1.3.12] (but
typically, <a href="definitions.html#Deadlock">deadlock</a>.)</td>
</tr>
</table>
<table summary="lock effects" border="1" cellpadding="5">
<tr>
<td><i><a href="mutex_concept.html#LockingStrategies">Locking
Strategy</a><br>
of associated mutex</i></td>
<p>If the associated mutex is already locked by some other thread, places the
current thread in the <a href="definitions.html#State">Blocked</a> state until
the associated mutex is unlocked, after which the current thread is placed in
the <a href="definitions.html#State">Ready</a> state, eventually to be returned
to the <a href="definitions.html#State">Running</a> state.
<td><i>Effect if associated mutex is already locked by the
current thread</i></td>
</tr>
<p><b>Postcondition:</b> locked()
<tr>
<td>Recursive</td>
<p><b>Throws:</b> <a href="lock_error.html">lock_error</a> if <code>locked()</code> or
as indicated in <b>Effects</b>.</p>
<td>As if an additional lock were added to the mutex.</td>
</tr>
<hr>
<tr>
<td>Checked</td>
<h3>unlock</h3>
<td>Throws <a href="lock_error.html">lock_error</a>.</td>
</tr>
<tr>
<td>Unchecked</td>
<td>Undefined behavior [<a href="bibliography.html#ISO">ISO</a>
1.3.12] (but typically, <a href="definitions.html#Deadlock">
deadlock</a>.)</td>
</tr>
</table>
<p>If the associated mutex is already locked by some other thread,
places the current thread in the <a href="definitions.html#State">
Blocked</a> state until the associated mutex is unlocked, after which
the current thread is placed in the <a href="definitions.html#State">
Ready</a> state, eventually to be returned to the <a href=
"definitions.html#State">Running</a> state.</p>
<p><b>Postcondition:</b> locked()</p>
<p><b>Throws:</b> <a href="lock_error.html">lock_error</a> if <code>
locked()</code> or as indicated in <b>Effects</b>.</p>
<hr>
<h3>unlock</h3>
<pre>
void unlock();
</pre>
<p><b>Effects: </b>Unlocks the associated mutex.</p>
<p><b>Effects:</b> Unlocks the associated mutex.</p>
<p><b>Throws:</b> <a href="lock_error.html">lock_error</a> if <code>!locked()</code>.</p>
<hr>
<h3>const void* Conversion</h3>
<p><b>Throws:</b> <a href="lock_error.html">lock_error</a> if <code>
!locked()</code>.</p>
<hr>
<h3>const void* Conversion</h3>
<pre>
operator const void*() const;
</pre>
<p><b>Returns:</b> If the associated mutex is currently locked, a value convertible to
<code>true</code>, else a value convertible to <code>false</code>.</p>
<p><b>Returns:</b> If the associated mutex is currently locked, a value
convertible to <code>true</code>, else a value convertible to <code>
false</code>.</p>
<p><b>Rationale:</b> A <code>const void*</code> conversion is considered safer than a
conversion to <code>bool</code>.</p>
<p><b>Rationale:</b> A <code>const void*</code> conversion is
considered safer than a conversion to <code>bool</code>.</p>
<hr>
<hr>
<h3>locked</h3>
<h3>locked</h3>
<pre>
bool locked() const;
</pre>
<p><b>Returns:</b> <code>this-&gt;operator const void*() != 0</code>.</p>
<hr>
<p><b>Returns:</b> <code>this-&gt;operator const void*() !=
0</code>.</p>
<hr>
<h2><a name="Example">Example</a> Usage</h2>
<h2><a name="Example">Example</a> Usage</h2>
<p>See the example given in the documentation for the <a href="mutex.html">mutex</a>
class.</p>
<p>See the example given in the documentation for the <a href=
"mutex.html">mutex</a> class.</p>
<hr>
<hr>
<p>Revised
<!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->05 November, 2001<!--webbot bot="Timestamp" endspan i-checksum="39359" --></p>
<p>Revised <!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->01 October, 2001<!--webbot bot="Timestamp" endspan i-checksum="38291" -->
</p>
<p><i>© Copyright <a href="mailto:williamkempf@hotmail.com">William E. Kempf</a>
2001 all rights reserved.</i></p>
</body>
<p><i>&copy; Copyright <a href="mailto:williamkempf@hotmail.com">
William E. Kempf</a> 2001 all rights reserved.</i></p>
</body>
</html>

View File

@@ -1,78 +1,87 @@
<html>
<head>
<meta http-equiv="Content-Type" content=
"text/html; charset=iso-8859-1">
<meta name="keywords" content="threads, BTL, thread library, C++">
<link rel="stylesheet" type="text/css" href="styles.css">
<head>
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<meta name="keywords" content="threads, BTL, thread library, C++">
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<title>Boost.Threads, scoped_timed_lock</title>
</head>
<title>Boost.Threads, scoped_timed_lock</title>
</head>
<body bgcolor="#FFFFFF" link="#0000FF" vlink="#800080">
<body bgcolor="#FFFFFF" link="#0000FF" vlink="#800080">
<table summary="header" border="0" cellpadding="7" cellspacing="0"
width="100%">
<tr>
<td valign="top" width="300">
<h3><img src="../../../c++boost.gif" alt="C++ Boost" width=
"277" height="86"></h3>
</td>
<table border="0" cellpadding="7" cellspacing="0" width="100%">
<tr>
<td valign="top" width="300">
<h3><img src="../../../c++boost.gif" alt="C++ Boost" width="277" height="86"></h3>
</td>
<td valign="top">
<h1 align="center">Boost.Threads</h1>
<h2 align="center">scoped_timed_lock</h2>
</td>
</tr>
</table>
<td valign="top">
<h1 align="center">Boost.Threads</h1>
<hr>
<h2 align="center">scoped_timed_lock</h2>
</td>
</tr>
</table>
<hr>
<p><a href="#Introduction">Introduction</a><br>
<a href="#Header">Header</a><br>
<a href="#Synopsis">Synopsis</a><br>
<a href="#Members">Members</a><br>
<a href="#Example">Example</a></p>
<p><a href="#Introduction">Introduction</a><br>
<a href="#Header">Header</a><br>
<a href="#Synopsis">Synopsis</a><br>
<a href="#Members">Members</a><br>
<a href="#Example">Example</a></p>
<h2><a name="Introduction">Introduction</a></h2>
<h2><a name="Introduction">Introduction</a></h2>
<p>This class template defines a generic lock type which meets the
<a href="lock_concept.html#ScopedTimedLock">ScopedTimedLock</a> requirements. The
<a href="mutex.html">timed_mutex</a> and
<a href="recursive_mutex.html">recursive_timed_mutex</a> classes use this template to
define their <code>scoped_timed_lock</code> types.</p>
<p>This class template defines a generic lock type which meets the <a
href="lock_concept.html#ScopedTimedLock">ScopedTimedLock</a>
requirements. The <a href="mutex.html">timed_mutex</a> and <a href=
"recursive_mutex.html">recursive_timed_mutex</a> classes use this
template to define their <code>scoped_timed_lock</code> types.</p>
<p>Like all the <b>Boost.Threads</b> <a href="lock_concept.html">lock models</a>,
<code>scoped_timed_lock</code> objects are meant to be short-lived. Objects of the
class are not <a href="definitions.html#thread-safe">thread-safe</a>, and so should
not be shared between threads.</p>
<p>Like all the <b>Boost.Threads</b> <a href="lock_concept.html">lock
models</a>, <code>scoped_timed_lock</code> objects are meant to be
short-lived. Objects of the class are not <a href=
"definitions.html#thread-safe">thread-safe</a>, and so should not be
shared between threads.</p>
<p>Class <code>scoped_timed_lock</code> follows the &quot;resource acquisition is
initialization&quot; idiom <a href="bibliography.html#Stroustrup-00">[Stroustrup
00 14.4.1]</a> and is a realization of the &quot;Scoped Locking Pattern&quot;
<a href="bibliography.html#Schmidt-00">[Schmidt-00]</a>. Thus the usage is to let the
constructor do the locking, and then let the destructor do the unlocking automatically
at the end of the enclosing scope. The lock() and unlock() members are usually not
explicitly called, but are provided to allow for complex overlapping locks of multiple
mutexes.</p>
<p>Class <code>scoped_timed_lock</code> follows the &quot;resource
acquisition is initialization&quot; idiom <a href=
"bibliography.html#Stroustrup-00">[Stroustrup 00 14.4.1]</a> and is a
realization of the &quot;Scoped Locking Pattern&quot; <a href=
"bibliography.html#Schmidt-00">[Schmidt-00]</a>. Thus the usage is to
let the constructor do the locking, and then let the destructor do the
unlocking automatically at the end of the enclosing scope. The lock()
and unlock() members are usually not explicitly called, but are
provided to allow for complex overlapping locks of multiple
mutexes.</p>
<p>The type used to instantiate the class must meet the
<a href="mutex_concept.html#TimedMutex">TimedMutex</a> requirements.</p>
<p>The type used to instantiate the class must meet the <a href=
"mutex_concept.html#TimedMutex">TimedMutex</a> requirements.</p>
<p>Although this class is an implementation detail, it is publicly documented here because
of its importance.</p>
<h2><a name="Header">Header</a></h2>
<p>Although this class is an implementation detail, it is publicly
documented here because of its importance.</p>
<h2><a name="Header">Header</a></h2>
<pre>
#include <a href="../../../boost/thread/detail/lock.hpp">&lt;boost/thread/detail/lock.hpp&gt;</a>
#include <a href=
"../../../boost/thread/detail/lock.hpp">&lt;boost/thread/detail/lock.hpp&gt;</a>
<i>This header is usually not included directly by programmers
because it is supplied by <a href="../../../boost/thread/mutex.hpp">&lt;boost/thread/mutex.hpp&gt;</a> or
<a href="../../../boost/thread/recursive_mutex.hpp">&lt;boost/thread/recursive_mutex.hpp&gt;</a></i>
because it is supplied by <a href=
"../../../boost/thread/mutex.hpp">&lt;boost/thread/mutex.hpp&gt;</a> or
<a href=
"../../../boost/thread/recursive_mutex.hpp">&lt;boost/thread/recursive_mutex.hpp&gt;</a></i>
</pre>
<h2><a name="Synopsis">Synopsis</a></h2>
<h2><a name="Synopsis">Synopsis</a></h2>
<pre>
namespace boost { namespace detail { namespace thread {
template &lt;typename TimedMutex&gt;
class scoped_timed_lock : private <a href="../../utility/utility.htm#Class noncopyable">boost::noncopyable</a> // Exposition only.
// Class scoped_timed_lock meets the <a href="overview.html#NonCopyable">NonCopyable</a> requirement.
class scoped_timed_lock : private <a href=
"../../utility/utility.htm#Class noncopyable">boost::noncopyable</a> // Exposition only.
// Class scoped_timed_lock meets the <a href=
"overview.html#NonCopyable">NonCopyable</a> requirement.
{
public:
typedef TimedMutex mutex_type;
@@ -92,138 +101,137 @@ namespace boost { namespace detail { namespace thread {
} // namespace boost
</pre>
<h2><a name="Members">Members</a></h2>
<hr>
<h3>Constructor</h3>
<h2><a name="Members">Members</a></h2>
<hr>
<h3>Constructor</h3>
<pre>
scoped_timed_lock(TimedMutex&amp; mx, const <a href="xtime.html">xtime</a>&amp; xt);
scoped_timed_lock(TimedMutex&amp; mx, const <a href=
"xtime.html">xtime</a>&amp; xt);
</pre>
<p><b>Effects:</b> Associates mutex <code>mx</code> with <code>*this</code>.
Calls <code>timed_lock</code>( <code>xt</code>)</p>
<hr>
<p><b>Effects:</b> Associates mutex <code>mx</code> with <code>
*this</code>. Calls <code>timed_lock</code>( <code>xt</code>)</p>
<hr>
<pre>
scoped_timed_lock(TimedMutex&amp; mx, bool initially_locked);
</pre>
<p><b>Effects:</b> Associates mutex <code>mx</code> with <code>*this</code>.
If <code>initially_locked</code> is <code>true</code>, calls <code>lock()</code>.</p>
<hr>
<h3>Destructor</h3>
<p><b>Effects:</b> Associates mutex <code>mx</code> with <code>
*this</code>. If <code>initially_locked</code> is <code>true</code>,
calls <code>lock()</code>.</p>
<hr>
<h3>Destructor</h3>
<pre>
~scoped_timed_lock();
</pre>
<p><b>Effects:</b> If <code> locked()</code>, calls <code>unlock()</code>. Destroys
<code>*this</code>.</p>
<hr>
<h3>lock</h3>
<p><b>Effects:</b> If <code>locked()</code>, calls <code>
unlock()</code>. Destroys <code>*this</code>.</p>
<hr>
<h3>lock</h3>
<pre>
void lock();
</pre>
<p><b>Effects:</b> If the associated mutex is already locked by another lock in the
current thread, the effects depend on the locking strategy of the associated mutex, as
shown in the following table:</p>
<p><b>Effects:</b> If the associated mutex is already locked by another
lock in the current thread, the effects depend on the locking strategy
of the associated mutex, as shown in the following table:</p>
<table border="1" cellpadding="5">
<tr>
<td><i><a href="mutex_concept.html#LockingStrategies">Locking Strategy</a><br>
of associated mutex</i></td>
<td><i>Effect if associated mutex is already locked by the current thread</i></td>
</tr>
<tr>
<td>Recursive</td>
<td>As if an additional lock were added to the mutex.</td>
</tr>
<tr>
<td>Checked</td>
<td>Throws <a href="lock_error.html">lock_error</a>.</td>
</tr>
<tr>
<td>Unchecked</td>
<td>Undefined behavior [<a href="bibliography.html#ISO">ISO</a> 1.3.12] (but
typically, <a href="definitions.html#Deadlock">deadlock</a>.)</td>
</tr>
</table>
<table summary="lock effects" border="1" cellpadding="5">
<tr>
<td><i><a href="mutex_concept.html#LockingStrategies">Locking
Strategy</a><br>
of associated mutex</i></td>
<p>If the associated mutex is already locked by some other thread, places the
current thread in the <a href="definitions.html#State">Blocked</a> state until
the associated mutex is unlocked, after which the current thread is placed in
the <a href="definitions.html#State">Ready</a> state, eventually to be returned
to the <a href="definitions.html#State">Running</a> state. Places the associated
mutex in the locked state.
<td><i>Effect if associated mutex is already locked by the
current thread</i></td>
</tr>
<p><b>Throws:</b> <a href="lock_error.html">lock_error</a> if <code>locked()</code> or
as indicated in <b>Effects</b>.</p>
<tr>
<td>Recursive</td>
<hr>
<td>As if an additional lock were added to the mutex.</td>
</tr>
<h3>timed_lock</h3>
<tr>
<td>Checked</td>
<td>Throws <a href="lock_error.html">lock_error</a>.</td>
</tr>
<tr>
<td>Unchecked</td>
<td>Undefined behavior [<a href="bibliography.html#ISO">ISO</a>
1.3.12] (but typically, <a href="definitions.html#Deadlock">
deadlock</a>.)</td>
</tr>
</table>
<p>If the associated mutex is already locked by some other thread,
places the current thread in the <a href="definitions.html#State">
Blocked</a> state until the associated mutex is unlocked, after which
the current thread is placed in the <a href="definitions.html#State">
Ready</a> state, eventually to be returned to the <a href=
"definitions.html#State">Running</a> state. Places the associated mutex
in the locked state.</p>
<p><b>Throws:</b> <a href="lock_error.html">lock_error</a> if <code>
locked()</code> or as indicated in <b>Effects</b>.</p>
<hr>
<h3>timed_lock</h3>
<pre>
bool timed_lock(const <a href="xtime.html">xtime</a>&amp; xt);
</pre>
<p><b>Effects:</b> Same as <code>lock()</code>, except that if xt is reached,
places the current thread in the <a href="definitions.html#State">Ready</a>
state without further ado.</p>
<p><b>Effects:</b> Same as <code>lock()</code>, except that if xt is
reached, places the current thread in the <a href=
"definitions.html#State">Ready</a> state without further ado.</p>
<p><b>Returns:</b> <code>locked()</code>.</p>
<p><b>Returns:</b> <code>locked()</code>.</p>
<p><b>Throws:</b> <a href="lock_error.html">lock_error</a> if <code>locked()</code> or
as indicated in <b>Effects</b>.</p>
<hr>
<h3>unlock</h3>
<p><b>Throws:</b> <a href="lock_error.html">lock_error</a> if <code>
locked()</code> or as indicated in <b>Effects</b>.</p>
<hr>
<h3>unlock</h3>
<pre>
void unlock();
</pre>
<p><b>Effects: </b>Unlocks the associated mutex.</p>
<p><b>Effects:</b> Unlocks the associated mutex.</p>
<p><b>Throws:</b> <a href="lock_error.html">lock_error</a> if <code>!locked()</code>.</p>
<hr>
<h3>const void* Conversion</h3>
<p><b>Throws:</b> <a href="lock_error.html">lock_error</a> if <code>
!locked()</code>.</p>
<hr>
<h3>const void* Conversion</h3>
<pre>
operator const void*() const;
</pre>
<p><b>Returns:</b> If the associated mutex is currently locked, a value convertible to
<code>true</code>, else a value convertible to <code>false</code>.</p>
<p><b>Returns:</b> If the associated mutex is currently locked, a value
convertible to <code>true</code>, else a value convertible to <code>
false</code>.</p>
<p><b>Rationale:</b> A <code>const void*</code> conversion is considered safer than a
conversion to <code>bool</code>.</p>
<hr>
<h3>locked</h3>
<p><b>Rationale:</b> A <code>const void*</code> conversion is
considered safer than a conversion to <code>bool</code>.</p>
<hr>
<h3>locked</h3>
<pre>
bool locked() const;
</pre>
<p><b>Returns:</b> <code>this-&gt;operator const void*() != 0</code>.</p>
<hr>
<h2><a name="Example">Example</a> Usage</h2>
<p><b>Returns:</b> <code>this-&gt;operator const void*() !=
0</code>.</p>
<hr>
<h2><a name="Example">Example</a> Usage</h2>
<pre>
#include &lt;boost/thread/mutex.hpp&gt;
#include &lt;iostream&gt;
@@ -243,19 +251,17 @@ int main(int, char*[])
}
</pre>
<p>The output is:</p>
<p>The output is:</p>
<pre>
locked
</pre>
<hr>
<hr>
<p>Revised
<!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%B %d, %Y" startspan -->November 05, 2001<!--webbot bot="Timestamp" endspan i-checksum="39585" --></p>
<p>Revised <!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%B %d, %Y" startspan -->October 01, 2001<!--webbot bot="Timestamp" endspan i-checksum="30079" -->
</p>
<p><i>© Copyright <a href="mailto:williamkempf@hotmail.com">William E. Kempf</a>
2001 all rights reserved.</i></p>
</body>
<p><i>&copy; Copyright <a href="mailto:williamkempf@hotmail.com">
William E. Kempf</a> 2001 all rights reserved.</i></p>
</body>
</html>

View File

@@ -1,78 +1,89 @@
<html>
<head>
<meta http-equiv="Content-Type" content=
"text/html; charset=iso-8859-1">
<meta name="keywords" content="threads, BTL, thread library, C++">
<link rel="stylesheet" type="text/css" href="styles.css">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<meta name="keywords" content="threads, BTL, thread library, C++">
<link rel="stylesheet" type="text/css" href="styles.css">
<title>Boost.Threads, scoped_try_lock</title>
</head>
<title>Boost.Threads, scoped_try_lock</title>
</head>
<body bgcolor="#FFFFFF" link="#0000FF" vlink="#800080">
<body bgcolor="#FFFFFF" link="#0000FF" vlink="#800080">
<table summary="header" border="0" cellpadding="7" cellspacing="0"
width="100%">
<tr>
<td valign="top" width="300">
<h3><img src="../../../c++boost.gif" alt="C++ Boost" width=
"277" height="86"></h3>
</td>
<table border="0" cellpadding="7" cellspacing="0" width="100%">
<tr>
<td valign="top" width="300">
<h3><img src="../../../c++boost.gif" alt="C++ Boost" width="277" height="86"></h3>
</td>
<td valign="top">
<h1 align="center">Boost.Threads</h1>
<h2 align="center">scoped_try_lock</h2>
</td>
</tr>
</table>
<td valign="top">
<h1 align="center">Boost.Threads</h1>
<hr>
<h2 align="center">scoped_try_lock</h2>
</td>
</tr>
</table>
<hr>
<p><a href="#Introduction">Introduction</a><br>
<a href="#Header">Header</a><br>
<a href="#Synopsis">Synopsis</a><br>
<a href="#Members">Members</a><br>
<a href="#Example">Example</a></p>
<p><a href="#Introduction">Introduction</a><br>
<a href="#Header">Header</a><br>
<a href="#Synopsis">Synopsis</a><br>
<a href="#Members">Members</a><br>
<a href="#Example">Example</a></p>
<h2><a name="Introduction">Introduction</a></h2>
<h2><a name="Introduction">Introduction</a></h2>
<p>This class template defines a generic lock type which meets the
<a href="lock_concept.html#ScopedTryLock">ScopedTryLock</a> requirements. The
<a href="mutex.html">try_mutex</a>, <a href="mutex.html">timed_mutex</a>,
<a href="recursive_mutex.html">recursive_try_mutex</a> and
<a href="recursive_mutex.html">recursive_timed_mutex</a> classes use this template
to define their <code>scoped_try_lock</code> types.</p>
<p>This class template defines a generic lock type which meets the <a
href="lock_concept.html#ScopedTryLock">ScopedTryLock</a> requirements.
The <a href="mutex.html">try_mutex</a>, <a href="mutex.html">
timed_mutex</a>, <a href="recursive_mutex.html">recursive_try_mutex</a>
and <a href="recursive_mutex.html">recursive_timed_mutex</a> classes
use this template to define their <code>scoped_try_lock</code>
types.</p>
<p>Like all the <b>Boost.Threads</b> <a href="lock_concept.html">lock models</a>,
<code>scoped_try_lock</code> objects are meant to be short-lived. Objects of the
class are not <a href="definitions.html#thread-safe">thread-safe</a>, and
so should not be shared between threads.</p>
<p>Like all the <b>Boost.Threads</b> <a href="lock_concept.html">lock
models</a>, <code>scoped_try_lock</code> objects are meant to be
short-lived. Objects of the class are not <a href=
"definitions.html#thread-safe">thread-safe</a>, and so should not be
shared between threads.</p>
<p>Class <code> scoped_try_lock</code> follows the &quot;resource acquisition is
initialization&quot; idiom <a href="bibliography.html#Stroustrup-00">[Stroustrup
00 14.4.1]</a> and is a realization of the &quot;Scoped Locking Pattern&quot;
<a href="bibliography.html#Schmidt-00">[Schmidt-00]</a>. Thus the usage is to let the
constructor do the locking, and then let the destructor do the unlocking automatically at
the end of the enclosing scope. The lock() and unlock() members are usually not
explicitly called, but are provided to allow for complex overlapping locks of multiple
mutexes.</p>
<p>Class <code>scoped_try_lock</code> follows the &quot;resource
acquisition is initialization&quot; idiom <a href=
"bibliography.html#Stroustrup-00">[Stroustrup 00 14.4.1]</a> and is a
realization of the &quot;Scoped Locking Pattern&quot; <a href=
"bibliography.html#Schmidt-00">[Schmidt-00]</a>. Thus the usage is to
let the constructor do the locking, and then let the destructor do the
unlocking automatically at the end of the enclosing scope. The lock()
and unlock() members are usually not explicitly called, but are
provided to allow for complex overlapping locks of multiple
mutexes.</p>
<p>Although this class is an implementation detail, it is publicly documented here because
of its importance.</p>
<p>Although this class is an implementation detail, it is publicly
documented here because of its importance.</p>
<p>The type used to instantiate the class must meet the <a href="mutex_concept.html#TryMutex">TryMutex</a> requirements.</p>
<h2><a name="Header">Header</a></h2>
<p>The type used to instantiate the class must meet the <a href=
"mutex_concept.html#TryMutex">TryMutex</a> requirements.</p>
<h2><a name="Header">Header</a></h2>
<pre>
#include <a href="../../../boost/thread/detail/lock.hpp">&lt;boost/thread/detail/lock.hpp&gt;</a>
#include <a href=
"../../../boost/thread/detail/lock.hpp">&lt;boost/thread/detail/lock.hpp&gt;</a>
<i>This header is usually not included directly by programmers
because it is supplied by <a href="../../../boost/thread/mutex.hpp">&lt;boost/thread/mutex.hpp&gt;</a> or
<a href="../../../boost/thread/recursive_mutex.hpp">&lt;boost/thread/recursive_mutex.hpp&gt;</a></i>
because it is supplied by <a href=
"../../../boost/thread/mutex.hpp">&lt;boost/thread/mutex.hpp&gt;</a> or
<a href=
"../../../boost/thread/recursive_mutex.hpp">&lt;boost/thread/recursive_mutex.hpp&gt;</a></i>
</pre>
<h2><a name="Synopsis">Synopsis</a></h2>
<h2><a name="Synopsis">Synopsis</a></h2>
<pre>
namespace boost { namespace detail { namespace thread {
template &lt;typename TryMutex&gt;
class scoped_try_lock : private <a href="../../utility/utility.htm#Class noncopyable">boost::noncopyable</a> // Exposition only.
// Class scoped_try_lock meets the <a href="overview.html#NonCopyable">NonCopyable</a> requirement.
class scoped_try_lock : private <a href=
"../../utility/utility.htm#Class noncopyable">boost::noncopyable</a> // Exposition only.
// Class scoped_try_lock meets the <a href=
"overview.html#NonCopyable">NonCopyable</a> requirement.
{
public:
typedef TryMutex mutex_type;
@@ -92,164 +103,178 @@ namespace boost { namespace detail { namespace thread {
} // namespace boost
</pre>
<h2><a name="Members">Members</a></h2>
<hr>
<h3>Constructors</h3>
<h2><a name="Members">Members</a></h2>
<hr>
<h3>Constructors</h3>
<pre>
explicit scoped_try_lock(TryMutex&amp; mx);
</pre>
<p><b>Effects:</b> Associates mutex <code>mx</code> with <code>*this</code>.
Calls <code>try_lock()</code>.</p>
<hr>
<p><b>Effects:</b> Associates mutex <code>mx</code> with <code>
*this</code>. Calls <code>try_lock()</code>.</p>
<hr>
<pre>
scoped_try_lock(TryMutex&amp; mx, bool initially_locked);
</pre>
<p><b>Effects:</b> Associates mutex <code>mx</code> with <code>*this</code>.
If <code>initially_locked</code> is <code>true,</code> calls <code>lock()</code>.</p>
<hr>
<h3>Destructor</h3>
<p><b>Effects:</b> Associates mutex <code>mx</code> with <code>
*this</code>. If <code>initially_locked</code> is <code>true,</code>
calls <code>lock()</code>.</p>
<hr>
<h3>Destructor</h3>
<pre>
~scoped_try_lock();
</pre>
<p><b>Effects:</b> If <code>locked()</code>, calls <code>unlock()</code>. Destroys
<code>*this</code>.</p>
<hr>
<h3>lock</h3>
<p><b>Effects:</b> If <code>locked()</code>, calls <code>
unlock()</code>. Destroys <code>*this</code>.</p>
<hr>
<h3>lock</h3>
<pre>
void lock();
</pre>
<p><b>Effects:</b> If the associated mutex is already locked by another lock in the
current thread, the effects depend on the locking strategy of the associated mutex, as
shown in the following table:</p>
<p><b>Effects:</b> If the associated mutex is already locked by another
lock in the current thread, the effects depend on the locking strategy
of the associated mutex, as shown in the following table:</p>
<table border="1" cellpadding="5" height="147">
<tr>
<td height="34"><i><a href="mutex_concept.html#LockingStrategies">Locking Strategy</a><br>
of associated mutex</i></td>
<td height="34"><i>Effect if associated mutex is already locked by the
current thread</i></td>
</tr>
<tr>
<td height="19">Recursive</td>
<td height="19">As if an additional lock were added to the mutex.</td>
</tr>
<tr>
<td height="19">Checked</td>
<td height="19">Throws <a href="lock_error.html">lock_error</a>.</td>
</tr>
<tr>
<td height="19">Unchecked</td>
<td height="19">Undefined behavior [<a href="bibliography.html#ISO">ISO</a> 1.3.12] (but
typically, <a href="definitions.html#Deadlock">deadlock</a>.)</td>
</tr>
</table>
<table summary="lock effects" border="1" cellpadding="5" height="147">
<tr>
<td height="34"><i><a href=
"mutex_concept.html#LockingStrategies">Locking Strategy</a><br>
of associated mutex</i></td>
<p>If the associated mutex is already locked by some other thread, places the
current thread in the <a href="definitions.html#State">Blocked</a> state until
the associated mutex is unlocked, after which the current thread is placed in
the <a href="definitions.html#State">Ready</a> state, eventually to be returned
to the <a href="definitions.html#State">Running</a> state. Places the associated
mutex in the locked state.</p>
<td height="34"><i>Effect if associated mutex is already locked
by the current thread</i></td>
</tr>
<p><b>Throws:</b> <a href="lock_error.html">lock_error</a> if <code>locked()</code> or
as indicated in <b>Effects</b>.</p>
<tr>
<td height="19">Recursive</td>
<hr>
<td height="19">As if an additional lock were added to the
mutex.</td>
</tr>
<h3>try_lock</h3>
<tr>
<td height="19">Checked</td>
<td height="19">Throws <a href="lock_error.html">
lock_error</a>.</td>
</tr>
<tr>
<td height="19">Unchecked</td>
<td height="19">Undefined behavior [<a href=
"bibliography.html#ISO">ISO</a> 1.3.12] (but typically, <a
href="definitions.html#Deadlock">deadlock</a>.)</td>
</tr>
</table>
<p>If the associated mutex is already locked by some other thread,
places the current thread in the <a href="definitions.html#State">
Blocked</a> state until the associated mutex is unlocked, after which
the current thread is placed in the <a href="definitions.html#State">
Ready</a> state, eventually to be returned to the <a href=
"definitions.html#State">Running</a> state. Places the associated mutex
in the locked state.</p>
<p><b>Throws:</b> <a href="lock_error.html">lock_error</a> if <code>
locked()</code> or as indicated in <b>Effects</b>.</p>
<hr>
<h3>try_lock</h3>
<pre>
bool try_lock();
</pre>
<p><b>Effects:</b> If the associated mutex is already locked by another lock in the
current thread, the effects depend on the locking strategy of the associated mutex, as
shown in the following table:</p>
<p><b>Effects:</b> If the associated mutex is already locked by another
lock in the current thread, the effects depend on the locking strategy
of the associated mutex, as shown in the following table:</p>
<table border="1" cellpadding="5" height="147">
<tr>
<td height="34"><i><a href="mutex_concept.html#LockingStrategies">Locking Strategy</a><br>
of associated mutex</i></td>
<td height="34"><i>Effect if associated mutex is already locked by the
current thread</i></td>
</tr>
<tr>
<td height="19">Recursive</td>
<td height="19">As if an additional lock were added to the mutex.</td>
</tr>
<tr>
<td height="19">Checked</td>
<td height="19">Throws <a href="lock_error.html">lock_error</a>.</td>
</tr>
<tr>
<td height="19">Unspecified</td>
<td height="19">Undefined behavior [<a href="bibliography.html#ISO">ISO</a> 1.3.12] (but
typically, <a href="definitions.html#Deadlock">deadlock</a>.)</td>
</tr>
</table>
<table summary="try_lock effects" border="1" cellpadding="5" height=
"147">
<tr>
<td height="34"><i><a href=
"mutex_concept.html#LockingStrategies">Locking Strategy</a><br>
of associated mutex</i></td>
<p>If the associated mutex is not already locked by some other thread, locks the
associated mutex and returns true, else returns false.</p>
<td height="34"><i>Effect if associated mutex is already locked
by the current thread</i></td>
</tr>
<p><b>Returns:</b> See effects.</p>
<tr>
<td height="19">Recursive</td>
<p><b>Throws:</b> <a href="lock_error.html">lock_error</a> if <code>locked()</code> or
as indicated in <b>Effects</b>.</p>
<td height="19">As if an additional lock were added to the
mutex.</td>
</tr>
<hr>
<tr>
<td height="19">Checked</td>
<h3>unlock</h3>
<td height="19">Throws <a href="lock_error.html">
lock_error</a>.</td>
</tr>
<tr>
<td height="19">Unspecified</td>
<td height="19">Undefined behavior [<a href=
"bibliography.html#ISO">ISO</a> 1.3.12] (but typically, <a
href="definitions.html#Deadlock">deadlock</a>.)</td>
</tr>
</table>
<p>If the associated mutex is not already locked by some other thread,
locks the associated mutex and returns true, else returns false.</p>
<p><b>Returns:</b> See effects.</p>
<p><b>Throws:</b> <a href="lock_error.html">lock_error</a> if <code>
locked()</code> or as indicated in <b>Effects</b>.</p>
<hr>
<h3>unlock</h3>
<pre>
void unlock();
</pre>
<p><b>Effects: </b>Unlocks the associated mutex.</p>
<p><b>Effects:</b> Unlocks the associated mutex.</p>
<p><b>Throws:</b> <a href="lock_error.html">lock_error</a> if <code>!locked()</code>.</p>
<hr>
<h3>const void* Conversion</h3>
<p><b>Throws:</b> <a href="lock_error.html">lock_error</a> if <code>
!locked()</code>.</p>
<hr>
<h3>const void* Conversion</h3>
<pre>
operator const void*() const;
</pre>
<p><b>Returns:</b> If the associated mutex is currently locked, a value convertible to
<code>true</code>, else a value convertible to <code>false</code>.</p>
<p><b>Returns:</b> If the associated mutex is currently locked, a value
convertible to <code>true</code>, else a value convertible to <code>
false</code>.</p>
<p><b>Rationale:</b> A <code>const void*</code> conversion is considered safer
than a conversion to <code>bool</code>.</p>
<hr>
<h3>locked</h3>
<p><b>Rationale:</b> A <code>const void*</code> conversion is
considered safer than a conversion to <code>bool</code>.</p>
<hr>
<h3>locked</h3>
<pre>
bool locked() const;
</pre>
<p><b>Returns:</b> <code>this-&gt;operator const void*() != 0</code>.</p>
<hr>
<h2><a name="Example">Example</a> Usage</h2>
<p><b>Returns:</b> <code>this-&gt;operator const void*() !=
0</code>.</p>
<hr>
<h2><a name="Example">Example</a> Usage</h2>
<pre>
#include <a href="../../../boost/thread/mutex.hpp">&lt;boost/thread/mutex.hpp&gt;</a>
#include <a href=
"../../../boost/thread/mutex.hpp">&lt;boost/thread/mutex.hpp&gt;</a>
#include &lt;iostream&gt;
int main(int, char*[])
@@ -264,19 +289,17 @@ int main(int, char*[])
}
</pre>
<p>The output is:</p>
<p>The output is:</p>
<pre>
locked
</pre>
<hr>
<hr>
<p>Revised
<!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->05 November, 2001<!--webbot bot="Timestamp" endspan i-checksum="39359" --></p>
<p>Revised <!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->01 October, 2001<!--webbot bot="Timestamp" endspan i-checksum="38291" -->
</p>
<p><i>© Copyright <a href="mailto:williamkempf@hotmail.com">William E. Kempf</a>
2001 all rights reserved.</i></p>
</body>
<p><i>&copy; Copyright <a href="mailto:williamkempf@hotmail.com">
William E. Kempf</a> 2001 all rights reserved.</i></p>
</body>
</html>

View File

@@ -1,226 +0,0 @@
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<meta name="keywords" content="threads, BTL, thread library, C++">
<link rel="stylesheet" type="text/css" href="styles.css">
<title>Boost.Threads, semaphore</title>
</head>
<body bgcolor="#ffffff" link="#0000ff" vlink="#800080">
<table border="0" cellpadding="7" cellspacing="0" width="100%">
<tr>
<td valign="top" width="300">
<h3><IMG height=86 alt="C++ Boost" src="../../../c++boost.gif" width=277></h3>
</td>
<td valign="top">
<h1 align="center">Boost.Threads</h1>
<h2 align="center">semaphore</h2>
</td>
</tr>
</table>
<hr>
<p><a href="#Introduction">Introduction</a><br>
<a href="#Header">Header</a><br>
<a href="#Synopsis">Synopsis</a><br>
<a href="#Members">Members</a><br>
<a href="#Example">Example</a></p>
<h2><a name="Introduction">Introduction</a></h2>
<p>The <tt>semaphore</tt> class defines a classic synchronization primitive invented by the
Dutch computer scientist Edsger W. Dijkstra. A semaphore manages an internal counter. This
counter never goes below zero, or above a specified maximum value. When calling
<tt>semaphore::down</tt> the calling thread will block until the value is non-zero and then
decrement the value in a single atomic operation. When calling <tt>semaphore::up</tt> the
calling thread will increment the value in a single atomic operation, failing if the value has
already reached the specified maximum.</p>
<p><b>Rationale:</b> The semaphore is the simplest synchronization primitive available and is generally the
primitive used to build other synchronization concepts at some level of implementation. For this
reason <b>Boost.Threads</b> defines the <tt>semaphore</tt> type in the classic form. This simplifies
usage and implementation, but it means that the interface is not as safe as other <b>Boost.Threads</b>
interfaces.</p>
<p><b><a name="Danger">Danger</a>:</b> Unlike the <A href="mutex_concept.html">mutex models</a> supplied by <b>Boost.Threads,</b>
there is no <A href="lock_concept.html">lock_concept</a> for the semaphore to help ensure proper
usage. Great care must be taken when using a <tt>semaphore</tt> object to ensure
<a href="definitions.html#Deadlock"> deadlock</a> or <a href="definitions.html#Race condition">race conditions</a> do not occur.&nbsp;</p>
<p>The dangers are spelled out by <a href="bibliography.html#Andrews-83">[Andrews-83]</a>
(function names updated, see historical note below):&nbsp;</p>
<blockquote>
<p>Although semaphores can be used to program almost any kind of synchronization,
<b>down()</b> and <b>up()</b> are rather unstructured primitives, and so it is easy to err when using them. Execution of each critical section must begin with a
<b>down()</b> and end with a <b>up()</b> (on the same semaphore). Omitting a <b>down()</b>
or <b>up()</b>, or accidentally coding a <b>down()</b> on one semaphore and a <b>up()</b>
on another can have disastrous effects, since mutually exclusive execution would no longer be ensured. Also, when using semaphores, a programmer can forget to include in critical sections all statements that reference shared objects. This, too, could destroy the mutual exclusion required within critical sections. A second difficulty with using semaphores is that both condition synchronization and mutual exclusion are programmed using the same pair of primitives. This makes it difficult to identify the purpose of a given
<b>down()</b> or <b>up()</b> operation without looking at the other operations on the corresponding semaphore. Since mutual exclusion and condition synchronization are distinct concepts, they should have distinct notations.</p>
</blockquote>
<p><b>Historical note: </b>Dijkstra's original name for <b>down()</b> was <b>P</b>
(short for the Dutch &quot;passeren&quot;, &quot;to pass&quot;), and for <b>up()</b>
was <b>V</b> (short for the Dutch &quot;vrygeven&quot;, &quot;to release&quot;).</p>
<h2><a name="Header">Header</a></h2>
<pre>
#include <a href="../../../boost/thread/semaphore.hpp">&lt;boost/thread/semaphore.hpp&gt;</a>
</pre>
<h2><a name="Synopsis">Synopsis</a></h2>
<pre>
namespace boost
{
class semaphore : private <a href="../../utility/utility.htm#Class noncopyable">boost::noncopyable</a> // Exposition only.
// Class semaphore meets the <a href="overview.html#NonCopyable">NonCopyable</a> requirement.
{
public:
explicit semaphore(unsigned count=0, unsigned max=0);
~semaphore();
bool up(unsigned count=1, unsigned* prev=0);
void down();
bool down(const xtime&amp; xt);
private:
unsigned m_count; <i>exposition only [ISO 17.3.2.3/2]
</i> unsigned m_max; <i>exposition only [ISO 17.3.2.3/2]</i>
};
}
</pre>
<h2><a name="Members">Members</a></h2>
<hr>
<h3>Constructor</h3>
<pre>
explicit semaphore(unsigned count=0, unsigned max=0);
</pre>
<p><b>Effects:</b> As if:</p>
<p><code>&nbsp;&nbsp;&nbsp;&nbsp; m_count = count;<br>
&nbsp;&nbsp;&nbsp;&nbsp; m_max = (max == 0 ? std::numeric_limits&lt;unsigned&gt;::max()
? max );</code></p>
<hr>
<h3>Destructor</h3>
<pre>
~semaphore();
</pre>
<p><b>Effects:</b> Destroys <code>*this</code>.</p>
<hr>
<h3>up</h3>
<pre>
bool up(unsigned count=1, unsigned* prev=0);
</pre>
<p><b>Effects:</b> As if:</p>
<p><code>&nbsp;&nbsp;&nbsp; unsigned ct;<br>
&nbsp;&nbsp;&nbsp; bool ret;<br>
&nbsp;&nbsp;&nbsp; { // as a single atomic operation:<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; ct = m_count;<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; if (m_count == m_max) ret =
false;<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; else<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; {<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; ret =
true;<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; ++m_count;<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; }<br>
&nbsp;&nbsp;&nbsp; }<br>
&nbsp;&nbsp;&nbsp; if (prev) *prev = m_count;<br>
&nbsp;&nbsp;&nbsp; return ret;</code></p>
<hr>
<h3>down</h3>
<pre>
void down();
</pre>
<p><b>Effects:</b> If <code>m_count == 0</code>, places the current thread in
the <a href="definitions.html#State">blocked</a> state until <code>m_count != 0</code>.
Finally, <code>--m_count</code>.<code>&nbsp;</code></p>
<hr>
<pre>
bool down(const <a href="xtime.html">xtime</a>&amp; xt);
</pre>
<p><b>Effects:</b> If <code>m_count == 0</code>, places the current thread in
the <a href="definitions.html#State">blocked</a> state until <code>m_count != 0</code>
or <code>xt</code> is reached. Finally, <code>--m_count</code>.<code>&nbsp;</code></p>
<p><b>Returns:</b> If xt was reached, true, else false.</p>
<hr>
<h2><a name="Example">Example</a> Usage</h2>
<pre>
#include <a href="../../../boost/thread/semaphore.hpp">&lt;boost/thread/semaphore.hpp&gt;</a>
#include <a href="../../../boost/thread/thread.hpp">&lt;boost/thread/thread.hpp&gt;</a>
#include &lt;iostream&gt;
int global_data = 0;
boost::semaphore global_semaphore(1);
void change_global_data(void*)
{
global_semaphore.down();
++global_data;
std::cout &lt;&lt; &quot;global_data == &quot; &lt;&lt; global_data &lt;&lt; std::endl;
global_semaphore.up();
}
int main(int, char*[])
{
const int num_threads = 4;
boost::thread_group thrds;
for (int i=0; i &lt; num_threads; ++i)
thrds.create_thread(&amp;change_global_data, 0);
thrds.join_all();
return 0;
}
</pre>
<p>The output is:</p>
<pre>
global_data == 1
global_data == 2
global_data == 3
global_data == 4
</pre>
<hr>
<p>Revised <!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->01 October, 2001<!--webbot bot="Timestamp" endspan i-checksum="38291" -->
</p>
<p><i>© Copyright <A href="mailto:williamkempf@hotmail.com">William E. Kempf</a>
2001 all rights reserved.</i></p>
</body>
</html>

View File

@@ -1,82 +1,94 @@
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<meta name="keywords" content="threads, Boost.Threads, thread library, C++">
<link rel="stylesheet" type="text/css" href="styles.css">
<title>Boost.Threads, thread</title>
<link rel="stylesheet" type="text/css" href="../../../boost.css">
<title>Boost.Threads - &lt;boost/thread.hpp&gt;</title>
</head>
<body bgcolor="#ffffff" link="#0000ff" vlink="#800080">
<table border="0" cellpadding="7" cellspacing="0" width="100%">
<tr>
<td valign="top" width="300">
<h3><IMG height=86 alt="C++ Boost" src="../../../c++boost.gif" width=277></h3>
</td>
<td valign="top">
<h1 align="center">Boost.Threads</h1>
<h2 align="center">Class thread</h2>
</td>
</tr>
<body link="#0000ff" vlink="#800080">
<table border="0" cellpadding="7" cellspacing="0" width="100%" summary=
"header">
<tr>
<td valign="top" width="300">
<h3><a href="../../../index.htm"><img height="86" width="277" alt="C++ Boost" src="../../../c++boost.gif" border="0"></a></h3>
</td>
<td valign="top">
<h1 align="center">Boost.Threads</h1>
<h2 align="center">Header &lt;boost/thread.hpp&gt;</h2>
</td>
</tr>
</table>
<hr>
<p><A href="#Introduction">Introduction</A><br>
<A href="#Header">Header</A><br>
<A href="#Synopsis">Synopsis</A><br>
<A href="#Members">Members</A><br>
<A href="#Example">Example</A></p>
<h2><a name="Introduction">Introduction</a></h2>
<p>The <code>thread</code> class represents threads of execution, and provides
the functionality to create and manage threads within the <b>Boost.Threads</b>
library. See <A href="definitions.html">Definitions</A> for a precise description of
"thread of execution", and for definitions of threading related terms and of thread
states such as "blocked".</p>
<p>A thread of execution has an initial function. For the program's
initial thread, the initial function is <code>main()</code>. For other
threads, the initial function is <code>operator()</code> of the function object
passed to the class <code>thread</code> constructor.</p>
<p>A thread of execution is said to be "finished" or "finished execution" when its
initial function returns or is terminated. This includes completion of all thread
cleanup handlers, and completion of the normal C++ function return behaviors, such
as destruction of automatic storage (stack) objects and releasing any associated
implementation resources.</p>
<p>A thread object has an associated state which is either "joinable" or
"non-joinable".</p>
<p>Except as described below, the policy used by an implementation of
<b>Boost.Threads</b> to schedule transitions between thread states is unspecified.</p>
<p><b>Note: </b>Just as the lifetime of a file may be different from the
lifetime of an iostream object which represents the file, the lifetime of a
thread of execution may be different from the <code>thread</code> object which
represents the thread of execution. In particular, after a call to <code>join()</code>,
the thread of execution will no longer exist even though the <code>thread</code>
object continues to exist until the end of its normal lifetime. The
converse is also possible; if a <code>thread</code> object is destroyed without
<code>join()</code> having first been called, the thread of execution continues until
its initial function completes.</p>
<h2><a name="Header">Header</a></h2>
<pre>
#include <A href="../../../boost/thread/thread.hpp">&lt;boost/thread/thread.hpp&gt;</A>
</pre>
<h2><a name="Synopsis">Synopsis</a></h2>
<h2>Contents</h2>
<dl class="page-index">
<dt><a href="#introduction">Introduction</a></dt>
<dt><a href="#classes">Classes</a></dt>
<dl class="page-index">
<dt><a href="#class-thread">Class <code>thread</code></a></dt>
<dl class="page-index">
<dt><a href="#class-thread-synopsis">Class <code>thread</code> synopsis</a></dt>
<dt><a href="#class-thread-ctors">Class <code>thread</code> constructors
and destructor</a></dt>
<dt><a href="#class-thread-comparisons">Class <code>thread</code>
comparison functions</a></dt>
<dt><a href="#class-thread-modifiers">Class <code>thread</code> modifier
functions</a></dt>
<dt><a href="#class-thread-statics">Class <code>thread</code> static
functions</a></dt>
</dl>
<dt><a href="#class-thread_group">Class <code>thread_group</code></a></dt>
<dl class="page-index">
<dt><a href="#class-thread_group-synopsis">Class <code>thread_group</code> synopsis</a></dt>
<dt><a href="#class-thread_group-ctors">Class <code>thread_group</code> constructors
and destructor</a></dt>
<dt><a href="#class-thread_group-modifiers">Class <code>thread_group</code> modifier
functions</a></dt>
</dl>
</dl>
<dt><a href="#examples">Example(s)</a></dt>
<dl class="page-index">
<dt><a href="#example-thread">Simple usage of <code>boost::thread</code></a></dt>
<dt><a href="#example-thread_group">Simple usage of <code>boost::thread_group</code></a></dt>
</dl>
</dl>
<hr>
<h2><a name="introduction"></a>Introduction</h2>
<p>The <code>boost/thread.hpp</code> header contains classes used to create and manage threads.</p>
<h2><a name="classes"></a>Classes</h2>
<h3><a name="class-thread"></a>Class <code>thread</code></h3>
<p>The <code>thread</code> class represents threads of execution, and provides
the functionality to create and manage threads within the <b> Boost.Threads</b>
library. See <a href="definitions.html"> Definitions</a> for a precise description
of &quot;thread of execution&quot;, and for definitions of threading related
terms and of thread states such as &quot;blocked&quot;.</p>
<p>A thread of execution has an initial function. For the program&#39;s initial
thread, the initial function is <code>main()</code>. For other threads, the
initial function is <code>operator()</code> of the function object passed to
the class <code>thread</code> constructor.</p>
<p>A thread of execution is said to be &quot;finished&quot; or &quot;finished
execution&quot; when its initial function returns or is terminated. This includes
completion of all thread cleanup handlers, and completion of the normal C++
function return behaviors, such as destruction of automatic storage (stack)
objects and releasing any associated implementation resources.</p>
<p>A thread object has an associated state which is either &quot;joinable&quot;
or &quot;non-joinable&quot;.</p>
<p>Except as described below, the policy used by an implementation of <b>Boost.Threads</b>
to schedule transitions between thread states is unspecified.</p>
<p><b>Note:</b> Just as the lifetime of a file may be different from the lifetime
of an iostream object which represents the file, the lifetime of a thread of
execution may be different from the <code> thread</code> object which represents
the thread of execution. In particular, after a call to <code>join()</code>,
the thread of execution will no longer exist even though the <code>thread</code>
object continues to exist until the end of its normal lifetime. The converse
is also possible; if a <code>thread</code> object is destroyed without <code>join()</code>
having first been called, the thread of execution continues until its initial
function completes.</p>
<h4><a name="class-thread-synopsis"></a>Class <code>thread</code> synopsis</h4>
<pre>
namespace boost {
class thread : <a href="../../utility/utility.htm#noncopyable">boost::noncopyable</a> // Exposition only.
// Class thread meets the <a href="overview.html#NonCopyable">NonCopyable</a> requirement.
class thread : <a href=
"../../utility/utility.htm#Class noncopyable">boost::noncopyable</a> // Exposition only.
// Class thread meets the <a href=
"overview.html#non-copyable">NonCopyable</a> requirement.
{
public:
thread();
@@ -91,120 +103,192 @@ public:
static void sleep(const xtime&amp; xt);
static void yield();
};
} // namespace boost
</pre>
<h2><a name="Members">Members</a></h2>
<hr>
<h3>Constructors</h3>
<h4><a name="class-thread-ctors"></a>Class <code>thread</code> constructors and destructor</h4>
<pre>
thread();
thread();
</pre>
<p><b>Effects:</b> Constructs a <code>thread</code> object representing the current thread
of execution.</p>
<p><b>Postcondition:</b> <code>*this</code> is non-joinable.</p>
<p><b>Danger:</b> <code>*this</code> is valid only within the current thread.</p>
<dl class="function-semantics">
<dt><b>Effects:</b> Constructs a <code>thread</code> object representing
the current thread of execution.</dt>
<dt><b>Postconditions:</b> <code>*this</code> is non-joinable.</dt>
<dt><b>Danger:</b> <code>*this</code> is valid only within the current
thread.</dt>
</dl>
<pre>
thread(const <A href="../../function/index.html">boost::function0</A>&lt;void&gt;&amp; threadfunc);
thread(const <a href="../../function/index.html">boost::function0</a>&lt;void&gt;&amp; threadfunc);
</pre>
<p><b>Effects:</b> Starts a new thread of execution and constructs a <code>thread</code> object
representing it. Copies <code>threadfunc</code>
(which in turn copies the function object wrapped by <code>threadfunc</code>) to an
internal location which persists for the lifetime of the new thread of execution. Calls
<code>operator()</code> on the copy of the <code>threadfunc</code> function object in
the new thread of execution.</p>
<p><b>Postcondition:</b> <code>*this</code> is joinable.</p>
<p><b>Throws:</b> <code>boost::thread_resource_error</code> if a new thread of execution
cannot be started.</p>
<hr>
<h3>Destructor</h3>
<dl class="function-semantics">
<dt><b>Effects:</b> Starts a new thread of execution and constructs a
<code>thread</code> object representing it. Copies <code>
threadfunc</code> (which in turn copies the function object wrapped by
<code>threadfunc</code>) to an internal location which persists for the
lifetime of the new thread of execution. Calls <code>operator()</code>
on the copy of the <code>threadfunc</code> function object in the new
thread of execution.</dt>
<dt><b>Postconditions:</b> <code>*this</code> is joinable.</dt>
<dt><b>Throws:</b> <code>boost::thread_resource_error</code> if a new
thread of execution cannot be started.</dt>
</dl>
<pre>
~thread();
~thread();
</pre>
<p><b>Effects:</b> Destroys <code>*this</code>. The actual thread of execution may
continue to execute after the <code>thread</code> object has been destroyed.</p>
<p><b>Notes:</b> If <code>*this</code> is joinable the actual thread of execution
becomes "detached". Any resources used by the thread will be reclaimed when the
thread of execution completes. To ensure such a thread of execution runs to completion
before the <code>thread</code> object is destroyed, call <code>join()</code>.</p>
<hr>
<h3>Comparison Operators</h3>
<dl class="function-semantics">
<dt><b>Effects:</b> Destroys <code>*this</code>. The actual thread of
execution may continue to execute after the <code>thread</code> object
has been destroyed.</dt>
<dt><b>Note:</b> If <code>*this</code> is joinable the actual thread of
execution becomes &quot;detached&quot;. Any resources used by the
thread will be reclaimed when the thread of execution completes. To
ensure such a thread of execution runs to completion before the <code>
thread</code> object is destroyed, call <code>join()</code>.</dt>
</dl>
<h4><a name="class-thread-comparisons"></a>Class <code>thread</code> comparison functions</h4>
<pre>
bool operator==(const thread&amp; rhs);
bool operator==(const thread&amp; rhs) const;
</pre>
<p><b>Requires:</b> The thread is non-terminated or <code>*this</code> is joinable.</p>
<p><b>Returns:</b> <code>true</code> if <code>*this</code> and <code>rhs</code>
represent the same thread of execution.</p>
<dl class="function-semantics">
<dt><b>Requires:</b> The thread is non-terminated or <code>*this</code>
is joinable.</dt>
<dt><b>Returns:</b> <code>true</code> if <code>*this</code> and <code>
rhs</code> represent the same thread of execution.</dt>
</dl>
<pre>
bool operator!=(const thread&amp; rhs);
bool operator!=(const thread&amp; rhs) const;
</pre>
<p><b>Returns:</b> <code>!(*this==rhs)</code>.</p>
<hr>
<h3>join</h3>
<dl class="function-semantics">
<dt><b>Requires:</b> The thread is non-terminated or <code>*this</code>
is joinable.</dt>
<dt><b>Returns:</b> <code>!(*this==rhs)</code>.</dt>
</dl>
<h4><a name="class-thread-modifiers"></a>Class <code>thread</code> modifier functions</h4>
<pre>
void join();
void join();
</pre>
<p><b>Requires:</b> <code>*this</code> is joinable.</p>
<p><b>Effects:</b> The current thread of execution blocks until the initial function of
the thread of execution represented by <code>*this</code> finishes and all resources
are reclaimed.</p>
<p><b>Postcondition:</b> <code>*this</code> is non-joinable.</p>
<p><b>Note:</b></p> If <code>*this == thread()</code> the result is implementation defined.
If the implementation doesn't detect this the result will be
<a href="definitions.html#Deadlock">deadlock</a>.</p>
<hr>
<h3>sleep</h3>
<dl class="function-semantics">
<dt><b>Requires:</b> <code>*this</code> is joinable.</dt>
<dt><b>Effects:</b> The current thread of execution blocks until the
initial function of the thread of execution represented by <code>
*this</code> finishes and all resources are reclaimed.</dt>
<dt><b>Postconditions:</b> <code>*this</code> is non-joinable.</dt>
<dt><b>Notes:</b> If <code>*this == thread()</code> the result is
implementation defined. If the implementation doesn&#39;t detect this
the result will be <a href="definitions.html#Deadlock">
deadlock</a>.</dt>
</dl>
<h4><a name="class-thread-statics"></a>Class <code>thread</code> static functions</h4>
<pre>
static void sleep(const <a href="xtime.html">xtime</a>&amp; xt);
static void sleep(const <a href="xtime.html">xtime</a>&amp; xt);
</pre>
<p><b>Effects:</b> The current thread of execution blocks until <code>xt</code> is
reached.</p>
<hr>
<h3>yield</h3>
<dl class="function-semantics">
<dt><b>Effects:</b> The current thread of execution blocks until <code>
xt</code> is reached.</dt>
</dl>
<pre>
static void yield();
static void yield();
</pre>
<dl class="function-semantics">
<dt><b>Effects:</b> The current thread of execution is placed in the
&quot;ready&quot; state.</dt>
<dt><b>Notes:</b> Allow the current thread to give up the rest of its
time slice (or other scheduling quota) to another thread. Particularly
useful in non-preemptive implementations.</dt>
</dl>
<h3><a name="class-thread_group"></a>Class <code>thread_group</code></h3>
<p>The <tt>thread_group</tt> class provides a container for easy
grouping of threads to simplify several common thread creation and
management idioms.</p>
<p><b>Effects:</b> The current thread of execution is placed in the "ready" state.</p>
<p>All <tt>thread_group</tt> member functions are <a href=
"definitions.html#thread-safe">thread-safe</a>, except destruction.</p>
<p><b>Notes:</b> Allow the current thread to give up the rest of its time slice
(or other scheduling quota) to another thread. Particularly useful in non-preemptive
implementations.</p>
<hr>
<h2><a name="Example">Example Usage</a></h2>
<h4><a name="class-thread_group-synopsis"></a>Class <code>thread_group</code> synopsis</h4>
<pre>
namespace boost {
class thread_group : <a href=
"../../utility/utility.htm#Class noncopyable">boost::noncopyable</a>
{
public:
thread_group();
~thread_group();
thread* create_thread(const boost::function0&lt;void&gt;&amp; threadfunc);
void add_thread(thread* thrd);
void remove_thread(thread* thrd);
void join_all();
};
} // namespace boost
</pre>
<h4><a name="class-thread_group-ctors"></a>Class <code>thread_group</code> constructors and destructor</h4>
<pre>
thread_group();
</pre>
<dl class="function-semantics">
<dt><b>Effects:</b> Constructs an empty <code>thread_group</code>
container.</dt>
</dl>
<pre>
~thread_group();
</pre>
<dl class="function-semantics">
<dt><b>Effects:</b> Destroys each contained thread object. Destroys
<code>*this</code>.</dt>
<dt><b>Notes:</b> Behavior is undefined if another thread references
*this during the execution of the destructor.</dt>
</dl>
<h4><a name="class-thread_group-modifiers"></a>Class <code>thread_group</code> modifier functions</h4>
<pre>
thread* create_thread(const boost::function0&lt;void&gt;&amp; threadfunc);
</pre>
<dl class="function-semantics">
<dt><b>Effects:</b> Creates a new <tt>thread</tt> object that executes
<tt>threadfunc</tt> and adds it to the <tt>thread_group</tt> container
object&#39;s list of managed <tt>thread</tt> objects.</dt>
<dt><b>Returns:</b> Pointer to the newly created thread.</dt>
</dl>
<pre>
void add_thread(thread* thrd);
</pre>
<dl class="function-semantics">
<dt><b>Effects:</b> Adds <tt>thrd</tt> to the <tt>thread_group</tt>
object&#39;s list of managed <tt>thread</tt> objects. The <tt>thrd</tt>
object must have been allocated via operator new and will be deleted
when the group is destroyed.</dt>
</dl>
<pre>
void remove_thread(thread* thrd);
</pre>
<dl class="function-semantics">
<dt><b>Effects:</b> Removes <code>*this</code>&#39;s list of managed
<tt>thread</tt> objects.</dt>
<dt><b>Throws:</b> ? if <tt>thrd</tt> is not it <code>*this</code>&#39;s
list of managed <tt>thread</tt> objects.</dt>
</dl>
<pre>
void join_all();
</pre>
<dl class="function-semantics">
<dt><b>Effects:</b> Calls <code>join()</code> on each of the managed
<tt>thread</tt> objects.</dt>
</dl>
<h2><a name="functions"></a>Functions</h2>
<pre>
<a name="function-spec"></a>{{function}}
</pre>
<dl class="function-semantics">
<dt><b>Requires:</b> {{text}}</dt>
<dt><b>Effects:</b> {{text}}</dt>
<dt><b>Postconditions:</b> {{text}}</dt>
<dt><b>Returns:</b> {{text}}</dt>
<dt><b>Throws:</b> {{text}}</dt>
<dt><b>Complexity:</b> {{text}}</dt>
<dt><b>Rationale:</b> {{text}}</dt>
</dl>
<h2><a name="objects"></a>Objects</h2>
<p><a name="object-spec"></a>{{Object specifications}}</p>
<h2><a name="examples"></a>Example(s)</h2>
<h3><a name="example-thread"></a>Simple usage of <code>boost::thread</code></h3>
<pre>
#include &lt;boost/thread/thread.hpp&gt;
#include &lt;iostream&gt;
@@ -230,25 +314,59 @@ int main(int argc, char* argv[])
{
int secs = 5;
std::cout &lt;&lt; &quot;setting alarm for 5 seconds...&quot; &lt;&lt; std::endl;
boost::thread thrd(thread_alarm(secs));
thread_alarm alarm(secs);
boost::thread thrd(alarm);
thrd.join();
}
</pre>
<p>The output is:</p>
<p>The output is:</p>
<pre>
setting alarm for 5 seconds...
alarm sounded...
</pre>
<h3><a name="example-thread_group"></a>Simple usage of <code>boost::thread_group</code></h3>
<pre>
#include &lt;boost/thread/thread.hpp&gt;
#include &lt;iostream&gt;
<hr>
int count = 0;
boost::mutex mutex;
<p>Revised <!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->01 October, 2001<!--webbot bot="Timestamp" endspan i-checksum="38291" -->
void increment_count()
{
boost::mutex::lock lock(mutex);
std::cout &lt;&lt; &quot;count = &quot; &lt;&lt; ++count &lt;&lt; std::endl;
}
int main(int argc, char* argv[])
{
boost::thread_group threads;
for (int i = 0; i &lt; 10; ++i)
threads.create_thread(&amp;increment_count);
threads.join_all();
}
</pre>
<p>The output is:</p>
<pre>
count = 1
count = 2
count = 3
count = 4
count = 5
count = 6
count = 7
count = 8
count = 9
count = 10
</pre>
<p>Revised
<!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->
05 November, 2001
<!--webbot bot="Timestamp" endspan i-checksum="39359" -->
</p>
<p><i>© Copyright <A href="mailto:williamkempf@hotmail.com">William E. Kempf</A>
2001 all rights reserved.</i></p>
<p><i>&copy; Copyright <a href="mailto:{{address}}">{{author}}</a> 2002. All Rights
Reserved.</i></p>
</body>
</html>

View File

@@ -1,54 +1,58 @@
<html>
<head>
<meta http-equiv="Content-Type" content=
"text/html; charset=iso-8859-1">
<meta name="keywords" content="threads, BTL, thread library, C++">
<link rel="stylesheet" type="text/css" href="styles.css">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<meta name="keywords" content="threads, BTL, thread library, C++">
<link rel="stylesheet" type="text/css" href="styles.css">
<title>Boost.Threads, thread_group</title>
</head>
<title>Boost.Threads, thread_group</title>
</head>
<body bgcolor="#FFFFFF" link="#0000FF" vlink="#800080">
<body bgcolor="#FFFFFF" link="#0000FF" vlink="#800080">
<table summary="header" border="0" cellpadding="7" cellspacing="0"
width="100%">
<tr>
<td valign="top" width="300">
<h3><img src="../../../c++boost.gif" alt="C++ Boost" width=
"277" height="86"></h3>
</td>
<table border="0" cellpadding="7" cellspacing="0" width="100%">
<tr>
<td valign="top" width="300">
<h3><img src="../../../c++boost.gif" alt="C++ Boost" width="277" height="86"></h3>
</td>
<td valign="top">
<h1 align="center">Boost.Threads</h1>
<h2 align="center">thread_group</h2>
</td>
</tr>
</table>
<td valign="top">
<h1 align="center">Boost.Threads</h1>
<hr>
<h2 align="center">thread_group</h2>
</td>
</tr>
</table>
<hr>
<p><a href="#Introduction">Introduction</a><br>
<a href="#Header">Header</a><br>
<a href="#Synopsis">Synopsis</a><br>
<a href="#Members">Members</a><br>
<a href="#Example">Example</a></p>
<p><a href="#Introduction">Introduction</a><br>
<a href="#Header">Header</a><br>
<a href="#Synopsis">Synopsis</a><br>
<a href="#Members">Members</a><br>
<a href="#Example">Example</a></p>
<h2><a name="Introduction">Introduction</a></h2>
<h2><a name="Introduction">Introduction</a></h2>
<p>The <tt>thread_group</tt> class provides a container for easy grouping of threads to simplify several
common thread creation and management idioms.</p>
<p>The <tt>thread_group</tt> class provides a container for easy
grouping of threads to simplify several common thread creation and
management idioms.</p>
<p>All <tt>thread_group</tt> member functions are <a href="definitions.html#thread-safe">thread-safe</a>,
except destruction.</p>
<h2><a name="Header">Header</a></h2>
<p>All <tt>thread_group</tt> member functions are <a href=
"definitions.html#thread-safe">thread-safe</a>, except destruction.</p>
<h2><a name="Header">Header</a></h2>
<pre>
#include <a href="../../../boost/thread/thread.hpp">&lt;boost/thread/thread.hpp&gt;</a>
#include <a href=
"../../../boost/thread/thread.hpp">&lt;boost/thread/thread.hpp&gt;</a>
</pre>
<h2><a name="Synopsis">Synopsis</a></h2>
<h2><a name="Synopsis">Synopsis</a></h2>
<pre>
namespace boost
{
class thread_group : <a href="../../utility/utility.htm#noncopyable">boost::noncopyable</a>
class thread_group : <a href=
"../../utility/utility.htm#noncopyable">boost::noncopyable</a>
{
public:
thread_group();
@@ -60,85 +64,77 @@ namespace boost
void join_all();
};
}
</pre>
</pre>
<h2><a name="Members">Members</a></h2>
<hr>
<h3>Constructor</h3>
<h2><a name="Members">Members</a></h2>
<hr>
<h3>Constructor</h3>
<pre>
thread_group();
</pre>
<p><b>Effects:</b> Constructs an empty <tt>thread_group</tt> container.</p>
<hr>
<h3>Destructor</h3>
<p><b>Effects:</b> Constructs an empty <tt>thread_group</tt>
container.</p>
<hr>
<h3>Destructor</h3>
<pre>
~thread_group();
</pre>
<p><b>Effects:</b> Destroys each contained thread object.&nbsp; Destroys <code>*this</code>.</p>
<p><b>Effects:</b> Destroys each contained thread object. Destroys
<code>*this</code>.</p>
<p><b>Notes:</b> Behavior is undefined if another thread references *this during
the execution of the destructor.</p>
<hr>
<h3>create_thread</h3>
<p><b>Notes:</b> Behavior is undefined if another thread references
*this during the execution of the destructor.</p>
<hr>
<h3>create_thread</h3>
<pre>
thread* create_thread(const boost::function0&lt;void&gt;&amp; threadfunc);
</pre>
<p><b>Effects:</b> Creates a new <tt>thread</tt> object that executes <tt>threadfunc</tt> and adds it to the
<tt>thread_group</tt> container object's list of managed <tt>thread</tt> objects.</p>
<p><b>Effects:</b> Creates a new <tt>thread</tt> object that executes
<tt>threadfunc</tt> and adds it to the <tt>thread_group</tt> container
object&#39;s list of managed <tt>thread</tt> objects.</p>
<p><b>Returns:</b> Pointer to the newly created thread.</p>
<hr>
<h3>add_thread</h3>
<p><b>Returns:</b> Pointer to the newly created thread.</p>
<hr>
<h3>add_thread</h3>
<pre>
void add_thread(thread* thrd);
</pre>
<p><b>Effects:</b> Adds <tt>thrd</tt> to the <tt>thread_group</tt> object's list of managed <tt>thread</tt>
objects. The <tt>thrd</tt> object must have been allocated via operator new and will
be deleted when the group is destroyed.</p>
<hr>
<h3>remove_thread</h3>
<p><b>Effects:</b> Adds <tt>thrd</tt> to the <tt>thread_group</tt>
object&#39;s list of managed <tt>thread</tt> objects. The <tt>thrd</tt>
object must have been allocated via operator new and will be deleted
when the group is destroyed.</p>
<hr>
<h3>remove_thread</h3>
<pre>
void remove_thread(thread* thrd);
</pre>
<p><b>Effects:</b> Removes <code>*this</code>'s list of managed <tt>thread</tt>
objects.</p>
<p><b>Effects:</b> Removes <code>*this</code>&#39;s list of managed
<tt>thread</tt> objects.</p>
<p><b>Throws: </b>? if <tt>thrd</tt> is not it <code>*this</code>'s list of managed <tt>thread</tt>
objects.</p>
<hr>
<h3>join_all</h3>
<p><b>Throws:</b> ? if <tt>thrd</tt> is not it <code>*this</code>&#39;s
list of managed <tt>thread</tt> objects.</p>
<hr>
<h3>join_all</h3>
<pre>
void join_all();
</pre>
<p><b>Effects:</b> Calls <code> join()</code> on each of the managed <tt>thread</tt> objects.</p>
<hr>
<h2><a name="Example">Example</a> Usage</h2>
<p><b>Effects:</b> Calls <code>join()</code> on each of the managed
<tt>thread</tt> objects.</p>
<hr>
<h2><a name="Example">Example</a> Usage</h2>
<pre>
#include &lt;boost/thread/thread.hpp&gt;
#include &lt;iostream&gt;
@@ -161,8 +157,7 @@ int main(int argc, char* argv[])
}
</pre>
<p>The output is:</p>
<p>The output is:</p>
<pre>
count = 1
count = 2
@@ -175,13 +170,13 @@ count = 8
count = 9
count = 10
</pre>
<hr>
<hr>
<p>Revised <!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->01 October, 2001<!--webbot bot="Timestamp" endspan i-checksum="38291" -->
</p>
<p>Revised
<!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->05 November, 2001<!--webbot bot="Timestamp" endspan i-checksum="39359" --></p>
<p><i>© Copyright <a href="mailto:williamkempf@hotmail.com">William E. Kempf</a>
2001 all rights reserved.</i></p>
</body>
<p><i>&copy; Copyright <a href="mailto:williamkempf@hotmail.com">
William E. Kempf</a> 2001 all rights reserved.</i></p>
</body>
</html>

View File

@@ -1,50 +1,51 @@
<html>
<head>
<meta http-equiv="Content-Type" content=
"text/html; charset=iso-8859-1">
<meta name="keywords" content="threads, BTL, thread library, C++">
<link rel="stylesheet" type="text/css" href="styles.css">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<meta name="keywords" content="threads, BTL, thread library, C++">
<link rel="stylesheet" type="text/css" href="styles.css">
<title>Boost.Threads, thread_resource_error</title>
</head>
<title>Boost.Threads, thread_resource_error</title>
</head>
<body bgcolor="#FFFFFF" link="#0000FF" vlink="#800080">
<body bgcolor="#FFFFFF" link="#0000FF" vlink="#800080">
<table summary="header" border="0" cellpadding="7" cellspacing="0" width="100%">
<tr>
<td valign="top" width="300">
<h3><img src="../../../c++boost.gif" alt="C++ Boost" width=
"277" height="86"></h3>
</td>
<table border="0" cellpadding="7" cellspacing="0" width="100%">
<tr>
<td valign="top" width="300">
<h3><img src="../../../c++boost.gif" alt="C++ Boost" width="277" height="86"></h3>
</td>
<td valign="top">
<h1 align="center">Boost.Threads</h1>
<h2 align="center">thread_resource_error</h2>
</td>
</tr>
</table>
<td valign="top">
<h1 align="center">Boost.Threads</h1>
<hr>
<h2 align="center">thread_resource_error</h2>
</td>
</tr>
</table>
<hr>
<p><a href="#Introduction">Introduction</a><br>
<a href="#Header">Header</a><br>
<a href="#Synopsis">Synopsis</a><br>
<a href="#Members">Members</a><br>
<a href="#Example">Example</a></p>
<p><a href="#Introduction">Introduction</a><br>
<a href="#Header">Header</a><br>
<a href="#Synopsis">Synopsis</a><br>
<a href="#Members">Members</a><br>
<a href="#Example">Example</a></p>
<h2><a name="Introduction">Introduction</a></h2>
<h2><a name="Introduction">Introduction</a></h2>
<p>The <code>thread_resource_error</code> class defines an exception type that is thrown
by constructors in the <b>Boost.Threads</b> library when thread related resources
can not be
acquired. This does not include memory allocation failures which instead throw
std::bad_alloc.</p>
<h2><a name="Header">Header</a></h2>
<p>The <code>thread_resource_error</code> class defines an exception
type that is thrown by constructors in the <b>Boost.Threads</b> library
when thread related resources can not be acquired. This does not
include memory allocation failures which instead throw
std::bad_alloc.</p>
<h2><a name="Header">Header</a></h2>
<pre>
#include <a href="../../../boost/thread/thread.hpp">&lt;boost/thread/exceptions.hpp&gt;</a>
#include <a href=
"../../../boost/thread/thread.hpp">&lt;boost/thread/exceptions.hpp&gt;</a>
</pre>
<h2><a name="Synopsis">Synopsis</a></h2>
<h2><a name="Synopsis">Synopsis</a></h2>
<pre>
namespace boost
{
@@ -56,25 +57,22 @@ namespace boost
}
</pre>
<h2><a name="Members">Members</a></h2>
<hr>
<h3>Constructor</h3>
<h2><a name="Members">Members</a></h2>
<hr>
<h3>Constructor</h3>
<pre>
thread_resource_error();
</pre>
<p>Constructs a <code>thread_resource_error</code> object.</p>
<p>Constructs a <code>thread_resource_error</code> object.</p>
<hr>
<hr>
<p>Revised
<!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->05 November, 2001<!--webbot bot="Timestamp" endspan i-checksum="39359" --></p>
<p>Revised <!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->01 October, 2001<!--webbot bot="Timestamp" endspan i-checksum="38291" -->
</p>
<p><i>© Copyright <a href="mailto:williamkempf@hotmail.com">William E. Kempf</a>
2001 all rights reserved.</i></p>
</body>
<p><i>&copy; Copyright <a href="mailto:williamkempf@hotmail.com">
William E. Kempf</a> 2001 all rights reserved.</i></p>
</body>
</html>

View File

@@ -1,70 +1,79 @@
<html>
<head>
<meta http-equiv="Content-Type" content=
"text/html; charset=iso-8859-1">
<meta name="keywords" content=
"threads, Boost.Threads, thread library, C++">
<link rel="stylesheet" type="text/css" href="styles.css">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<meta name="keywords" content="threads, Boost.Threads, thread library, C++">
<link rel="stylesheet" type="text/css" href="styles.css">
<title>Boost.Threads, thread_specific_ptr</title>
</head>
<title>Boost.Threads, thread_specific_ptr</title>
</head>
<body bgcolor="#FFFFFF" link="#0000FF" vlink="#800080">
<body bgcolor="#FFFFFF" link="#0000FF" vlink="#800080">
<table summary="header" border="0" cellpadding="7" cellspacing="0"
width="100%">
<tr>
<td valign="top" width="300">
<h3><img src="../../../c++boost.gif" alt="C++ Boost" width=
"277" height="86"></h3>
</td>
<table border="0" cellpadding="7" cellspacing="0" width="100%">
<tr>
<td valign="top" width="300">
<h3><img src="../../../c++boost.gif" alt="C++ Boost" width="277" height="86"></h3>
</td>
<td valign="top">
<h1 align="center">Boost.Threads</h1>
<h2 align="center">thread_specific_ptr</h2>
</td>
</tr>
</table>
<td valign="top">
<h1 align="center">Boost.Threads</h1>
<hr>
<h2 align="center">thread_specific_ptr</h2>
</td>
</tr>
</table>
<hr>
<p><A href="#Introduction">Introduction</A><br>
<A href="#Header">Header</A><br>
<A href="#Synopsis">Synopsis</A><br>
<A href="#Members">Members</A><br>
<A href="#Example">Example</A></p>
<p><a href="#Introduction">Introduction</a><br>
<a href="#Header">Header</a><br>
<a href="#Synopsis">Synopsis</a><br>
<a href="#Members">Members</a><br>
<a href="#Example">Example</a></p>
<h2><a name="Introduction">Introduction</a></h2>
<h2><a name="Introduction">Introduction</a></h2>
<p>The <code>thread_specific_ptr</code> class defines an interface for using thread
specific storage. Thread specific storage is data associated with individual threads
and is often used to make operations
<a href="definitions.html#Thread-safe">thread-safe</a> that rely on global data.</p>
<p>The <code>thread_specific_ptr</code> class defines an interface for
using thread specific storage. Thread specific storage is data
associated with individual threads and is often used to make operations
<a href="definitions.html#Thread-safe">thread-safe</a> that rely on
global data.</p>
<p>Template <code>thread_specific_ptr</code> stores a pointer to an object obtained via
<code>new</code> on a thread-by-thread basis and calls delete on the contained pointer
when the thread terminates. Each thread initially stores the null pointer in each
<code>thread_specific_ptr</code> instance.</p>
<p>Template <code>thread_specific_ptr</code> stores a pointer to an
object obtained via <code>new</code> on a thread-by-thread basis and
calls delete on the contained pointer when the thread terminates. Each
thread initially stores the null pointer in each <code>
thread_specific_ptr</code> instance.</p>
<p>The template <code>thread_specific_ptr</code> is useful in the following cases:</p>
<p>The template <code>thread_specific_ptr</code> is useful in the
following cases:</p>
<ul>
<li>An interface was original written assuming a single thread of control and is
being ported to a multi-threaded environment.</li>
<li>Each thread of control invokes sequences of methods that share data that must be
logically accessed through a globally visible access point, but are physically
unique for each thread, instead of being explicitly passed.</li>
</ul>
<ul>
<li>An interface was original written assuming a single thread of
control and is being ported to a multi-threaded environment.</li>
<h2><a name="Header">Header</a></h2>
<li>Each thread of control invokes sequences of methods that share
data that must be logically accessed through a globally visible
access point, but are physically unique for each thread, instead of
being explicitly passed.</li>
</ul>
<h2><a name="Header">Header</a></h2>
<pre>
#include <a href="../../../boost/thread/tss.hpp">&lt;boost/thread/tss.hpp&gt;</a>
#include <a href=
"../../../boost/thread/tss.hpp">&lt;boost/thread/tss.hpp&gt;</a>
</pre>
<h2><a name="Synopsis">Synopsis</a></h2>
<h2><a name="Synopsis">Synopsis</a></h2>
<pre>
namespace boost {
template &lt;typename T&gt;
class thread_specific_ptr : private boost::noncopyable // Exposition only.
// Class thread_specific_ptr meets the <a href="overview.html#NonCopyable">NonCopyable</a> requirement.
// Class thread_specific_ptr meets the <a href=
"overview.html#NonCopyable">NonCopyable</a> requirement.
{
public:
thread_specific_ptr();
@@ -78,100 +87,101 @@ public:
};
} // namespace boost
</pre>
</pre>
<h2><a name="Members">Members</a></h2>
<hr>
<h3>Constructor</h3>
<h2><a name="Members">Members</a></h2>
<hr>
<h3>Constructor</h3>
<pre>
thread_specific_ptr();
</pre>
<p><b>Postconditions:</b> A thread specific storage has been reserved for use by *this
in all threads, with each thread initially storing a null pointer.</p>
<p><b>Postconditions:</b> A thread specific storage has been reserved
for use by *this in all threads, with each thread initially storing a
null pointer.</p>
<p><b>Requires:</b> The expression <code>delete get()</code> is well formed.</p>
<p><b>Requires:</b> The expression <code>delete get()</code> is well
formed.</p>
<p><b>Throws:</b> <code>boost::thread_resource_error</code> if the necessary resources
can not be obtained.</p>
<p><b>Throws:</b> <code>boost::thread_resource_error</code> if the
necessary resources can not be obtained.</p>
<p><b>Notes:</b> There is an implementation specific limit to the number of thread
specific storage objects that can be created, and this limit may be small.</p>
<hr>
<h3>Destructor</h3>
<p><b>Notes:</b> There is an implementation specific limit to the
number of thread specific storage objects that can be created, and this
limit may be small.</p>
<hr>
<h3>Destructor</h3>
<pre>
~thread_specific_ptr();
</pre>
<p><b>Notes:</b> Does not destroy any data that may be stored in any thread's thread
specific storage. For this reason you should not destroy a
<code>thread_specific_ptr</code> object until you are certain there are no threads
running that have made use of its thread specific storage.</p>
<hr>
<h3>get</h3>
<p><b>Notes:</b> Does not destroy any data that may be stored in any
thread&#39;s thread specific storage. For this reason you should not
destroy a <code>thread_specific_ptr</code> object until you are certain
there are no threads running that have made use of its thread specific
storage.</p>
<hr>
<h3>get</h3>
<pre>
T* get() const;
</pre>
<p><b>Returns:</b> The object stored in thread specific storage for the current thread
for *this.</p>
<p><b>Returns:</b> The object stored in thread specific storage for the
current thread for *this.</p>
<p><b>Notes:</b> Each thread initially returns 0.</p>
<hr>
<h3>Smart Pointer Operations</h3>
<p><b>Notes:</b> Each thread initially returns 0.</p>
<hr>
<h3>Smart Pointer Operations</h3>
<pre>
T* operator-&gt;() const;
</pre>
<p><b>Returns:</b> <code>get()</code></p>
<p><b>Returns:</b> <code>get()</code></p>
<pre>
T&amp; operator*() const;
</pre>
<p><b>Returns:</b> <code>get()</code></p>
<p><b>Returns:</b> <code>get()</code></p>
<p><b>Requires:</b> <code>get() != 0</code></p>
<hr>
<h3>Release</h3>
<p><b>Requires:</b> <code>get() != 0</code></p>
<hr>
<h3>Release</h3>
<pre>
T* release();
</pre>
<p><b>Returns:</b> <code>get()</code></p>
<p><b>Returns:</b> <code>get()</code></p>
<p><b>Postcondition:</b> *this holds the null pointer for the current thread.</p>
<hr>
<h3>Reset</h3>
<p><b>Postcondition:</b> *this holds the null pointer for the current
thread.</p>
<hr>
<h3>Reset</h3>
<pre>
void reset(T* p=0);
</pre>
<p><b>Effects:</b> If <code>get()!= p</code> then <code>delete get()</code>.</p>
<p><b>Effects:</b> If <code>get()!= p</code> then <code>delete
get()</code>.</p>
<p><b>Postconditions:</b> <code>*this</code> holds the pointer <code>p</code> for
the current thread.</p>
<p><b>Postconditions:</b> <code>*this</code> holds the pointer <code>
p</code> for the current thread.</p>
<p><b>Notes:</b> The pointer will be deleted when the thread terminates.</p>
<hr>
<h2><a name="Example">Example Usage</a></h2>
<p><b>Notes:</b> The pointer will be deleted when the thread
terminates.</p>
<hr>
<h2><a name="Example">Example Usage</a></h2>
<pre>
#include <a href="../../../boost/thread/thread.hpp">&lt;boost/thread/thread.hpp&gt;</a>
#include <a href="../../../boost/thread/tss.hpp">&lt;boost/thread/tss.hpp&gt;</a>
#include <a href=
"../../../boost/thread/thread.hpp">&lt;boost/thread/thread.hpp&gt;</a>
#include <a href=
"../../../boost/thread/tss.hpp">&lt;boost/thread/tss.hpp&gt;</a>
#include &lt;cassert&gt;
boost::thread_specific_ptr&lt;int&gt; value;
@@ -184,7 +194,7 @@ void increment()
void thread_proc()
{
value.reset(new int(0)); // initialize the thread's storage
value.reset(new int(0)); // initialize the thread&#39;s storage
for (int i=0; i&lt;10; ++i)
{
increment();
@@ -201,14 +211,13 @@ int main(int argc, char* argv[])
threads.join_all();
}
</pre>
<hr>
<hr>
<p>Revised
<!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->05 November, 2001<!--webbot bot="Timestamp" endspan i-checksum="39359" --></p>
<p>Revised <!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->01 October, 2001<!--webbot bot="Timestamp" endspan i-checksum="38291" -->
</p>
<p><i>© Copyright <a href="mailto:williamkempf@hotmail.com">William E. Kempf</a>
2001 all rights reserved.</i></p>
</body>
<p><i>&copy; Copyright <a href="mailto:williamkempf@hotmail.com">
William E. Kempf</a> 2001 all rights reserved.</i></p>
</body>
</html>

View File

@@ -1,50 +1,54 @@
<html>
<head>
<meta http-equiv="Content-Type" content=
"text/html; charset=iso-8859-1">
<meta name="keywords" content=
"threads, Boost.Threads, thread library, C++">
<link rel="stylesheet" type="text/css" href="styles.css">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<meta name="keywords" content="threads, Boost.Threads, thread library, C++">
<link rel="stylesheet" type="text/css" href="styles.css">
<title>Boost.Threads, xtime</title>
</head>
<title>Boost.Threads, xtime</title>
</head>
<body bgcolor="#FFFFFF" link="#0000FF" vlink="#800080">
<body bgcolor="#FFFFFF" link="#0000FF" vlink="#800080">
<table summary="header" border="0" cellpadding="7" cellspacing="0"
width="100%">
<tr>
<td valign="top" width="300">
<h3><img src="../../../c++boost.gif" alt="C++ Boost" width=
"277" height="86"></h3>
</td>
<table border="0" cellpadding="7" cellspacing="0" width="100%">
<tr>
<td valign="top" width="300">
<h3><img src="../../../c++boost.gif" alt="C++ Boost" width="277" height="86"></h3>
</td>
<td valign="top">
<h1 align="center">Boost.Threads</h1>
<h2 align="center">xtime</h2>
</td>
</tr>
</table>
<td valign="top">
<h1 align="center">Boost.Threads</h1>
<hr>
<h2 align="center">xtime</h2>
</td>
</tr>
</table>
<hr>
<p><A href="#Introduction">Introduction</A><br>
<A href="#Header">Header</A><br>
<A href="#Synopsis">Synopsis</A><br>
<A href="#Reference">Reference</A><br>
<A href="#Example">Example</A></p>
<p><a href="#Introduction">Introduction</a><br>
<a href="#Header">Header</a><br>
<a href="#Synopsis">Synopsis</a><br>
<a href="#Reference">Reference</a><br>
<a href="#Example">Example</a></p>
<h2><a name="Introduction">Introduction</a></h2>
<h2><a name="Introduction">Introduction</a></h2>
<p>The <code>xtime</code> type is used to represent a point on some time scale or
a duration in time. This type may be proposed for the C standard by Markus Kuhn.
<b>Boost.Threads</b> provides only a very minimal implementation of this proposal
and it's expected that a full implementation will be provided in Boost as a separate
library, at which time <b>Boost.Threads</b> will deprecate its implementation.</p>
<h2><a name="Header">Header</a></h2>
<p>The <code>xtime</code> type is used to represent a point on some
time scale or a duration in time. This type may be proposed for the C
standard by Markus Kuhn. <b>Boost.Threads</b> provides only a very
minimal implementation of this proposal and it&#39;s expected that a
full implementation will be provided in Boost as a separate library, at
which time <b>Boost.Threads</b> will deprecate its implementation.</p>
<h2><a name="Header">Header</a></h2>
<pre>
#include <a href="../../../boost/thread/xtime.hpp">&lt;boost/thread/xtime.hpp&gt;</a>
#include <a href=
"../../../boost/thread/xtime.hpp">&lt;boost/thread/xtime.hpp&gt;</a>
</pre>
<h2><a name="Synopsis">Synopsis</a></h2>
<h2><a name="Synopsis">Synopsis</a></h2>
<pre>
namespace boost {
@@ -66,19 +70,19 @@ struct xtime
int xtime_get(struct xtime* xtp, int clock_type);
} // namespace boost
</pre>
</pre>
<h2><a name="Reference">Reference</a></h2>
<h2><a name="Reference">Reference</a></h2>
<hr>
<hr>
<h3>TIME_UTC</h3>
<h3>TIME_UTC</h3>
<p>The clock type for Coordinated Universal Time (UTC). The epoch for this clock type
is 1970-01-01 00:00:00. This is the only clock type supported by <b>Boost.Threads</b>.</p>
<hr>
<h3>xtime</h3>
<p>The clock type for Coordinated Universal Time (UTC). The epoch for
this clock type is 1970-01-01 00:00:00. This is the only clock type
supported by <b>Boost.Threads</b>.</p>
<hr>
<h3>xtime</h3>
<pre>
struct xtime
{
@@ -91,34 +95,37 @@ is 1970-01-01 00:00:00. This is the only clock type supported by <b>Boost.Thread
};
</pre>
<p><b>sec</b> represents the whole seconds that have passed since the epoch.</p>
<p><b>sec</b> represents the whole seconds that have passed since the
epoch.</p>
<p><b>nsec</b> represents the nanoseconds since <code>sec.</code>
<hr>
<h3>xtime_get</h3>
<p><b>nsec</b> represents the nanoseconds since <code>sec.</code></p>
<hr>
<h3>xtime_get</h3>
<pre>
int xtime_get(struct xtime* xtp, int clock_type);
</pre>
<p><b>Postcondition:</b> <code>xtp</code> represents the current point in time
as a duration since the epoch specified by the <code>clock_type</code>.</p>
<p><b>Postcondition:</b> <code>xtp</code> represents the current point
in time as a duration since the epoch specified by the <code>
clock_type</code>.</p>
<p><b>Returns:</b> <code>clock_type</code> if successful, otherwise 0.
<p><b>Returns:</b> <code>clock_type</code> if successful, otherwise
0.</p>
<p><b>Notes:</b> The resolution is implementation specific. For many
implementations the best resolution of time is far more than one nanosecond, and
even when the resolution is reasonably good, the latency of a call to <code>xtime_get()</code>
may be significant. For maximum portability, avoid durations of less than
one second.</p>
<hr>
<h2><a name="Example">Example Usage</a></h2>
<p><b>Notes:</b> The resolution is implementation specific. For many
implementations the best resolution of time is far more than one
nanosecond, and even when the resolution is reasonably good, the
latency of a call to <code>xtime_get()</code> may be significant. For
maximum portability, avoid durations of less than one second.</p>
<hr>
<h2><a name="Example">Example Usage</a></h2>
<pre>
#include <a href="../../../boost/thread/thread.hpp">&lt;boost/thread/thread.hpp&gt;</a>
#include <a href="../../../boost/thread/tss.hpp">&lt;boost/thread/xtime.hpp&gt;</a>
#include <a href=
"../../../boost/thread/thread.hpp">&lt;boost/thread/thread.hpp&gt;</a>
#include <a href=
"../../../boost/thread/tss.hpp">&lt;boost/thread/xtime.hpp&gt;</a>
int main(int argc, char* argv[])
{
@@ -128,14 +135,13 @@ int main(int argc, char* argv[])
boost::thread::sleep(xt); // Sleep for 1 second
}
</pre>
<hr>
<hr>
<p>Revised
<!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->05 November, 2001<!--webbot bot="Timestamp" endspan i-checksum="39359" --></p>
<p>Revised <!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->01 October, 2001<!--webbot bot="Timestamp" endspan i-checksum="38291" -->
</p>
<p><i>© Copyright <a href="mailto:williamkempf@hotmail.com">William E. Kempf</a>
2001 all rights reserved.</i></p>
</body>
<p><i>&copy; Copyright <a href="mailto:williamkempf@hotmail.com">
William E. Kempf</a> 2001 all rights reserved.</i></p>
</body>
</html>

2
example/.cvsignore Normal file
View File

@@ -0,0 +1,2 @@
bin
*.pdb

View File

@@ -0,0 +1,68 @@
# (C) Copyright William E. Kempf 2001. Permission to copy, use, modify, sell and
# distribute this software is granted provided this copyright notice appears
# in all copies. This software is provided "as is" without express or implied
# warranty, and with no claim as to its suitability for any purpose.
#
# Boost.Threads build and test Jamfile
#
# Declares the following targets:
# 1. monitor, an example program.
# 2. starvephil, an example program.
# 3. tennis, an example program.
# Additional configuration variables used:
# 1. PTW32 may be used on Win32 platforms to specify that the pthreads-win32
# library should be used instead of "native" threads. This feature is
# mostly used for testing and it's generally recommended you use the
# native threading libraries instead. PTW32 should be set to be a list
# of two strings, the first specifying the installation path of the
# pthreads-win32 library and the second specifying which library
# variant to link against (see the pthreads-win32 documentation).
# Example: jam -sPTW32="c:\pthreads-win32 pthreadVCE.lib"
# Declare the location of this subproject relative to the root.
subproject libs/thread/example ;
# Include threads.jam for Boost.Threads global build information.
# This greatly simplifies the Jam code needed to configure the build
# for the various Win32 build types.
SEARCH on <module@>threads.jam = $(BOOST_ROOT)/libs/thread/build ;
include <module@>threads.jam ;
#######################
# Declare the Boost.Threads example program monitor.
exe monitor
: monitor/monitor.cpp
<lib>../build/boost_thread
$(threadmon)
: <include>$(BOOST_ROOT)
$(pthreads-win32)
<threading>multi
: debug release <runtime-link>static/dynamic
;
#######################
# Declare the Boost.Threads example program starvephil.
exe starvephil
: starvephil/starvephil.cpp
<lib>../build/boost_thread
$(threadmon)
: <include>$(BOOST_ROOT)
$(pthreads-win32)
<threading>multi
: debug release <runtime-link>static/dynamic
;
#######################
# Declare the Boost.Threads example program tennis.
exe tennis
: tennis/tennis.cpp
<lib>../build/boost_thread
$(threadmon)
: <include>$(BOOST_ROOT)
$(pthreads-win32)
<threading>multi
: debug release <runtime-link>static/dynamic
;

1
example/monitor/Carbon.r Normal file
View File

@@ -0,0 +1 @@
/*

View File

@@ -8,19 +8,19 @@
namespace {
const int ITERS = 100;
boost::mutex io_mutex;
};
}
template <typename M>
class buffer_t
{
public:
typedef typename M::scoped_lock scoped_lock;
buffer_t(int n)
: p(0), c(0), full(0), buf(n)
{
}
void send(int m)
{
scoped_lock lk(mutex);
@@ -29,7 +29,7 @@ public:
buf[p] = m;
p = (p+1) % buf.size();
++full;
cond.notify_all();
cond.notify_one();
}
int receive()
{
@@ -39,41 +39,40 @@ public:
int i = buf[c];
c = (c+1) % buf.size();
--full;
cond.notify_all();
cond.notify_one();
return i;
}
static buffer_t& get_buffer()
{
static buffer_t buf(2);
return buf;
}
static void do_sender_thread()
{
for (int n = 0; n < ITERS; ++n)
{
get_buffer().send(n);
{
boost::mutex::scoped_lock lock(io_mutex);
std::cout << "sent: " << n << std::endl;
std::cout << "sending: " << n << std::endl;
}
get_buffer().send(n);
}
}
static void do_receiver_thread()
{
int n;
do
for (int x=0; x < (ITERS/2); ++x)
{
n = get_buffer().receive();
int n = get_buffer().receive();
{
boost::mutex::scoped_lock lock(io_mutex);
std::cout << "received: " << n << std::endl;
}
} while (n < ITERS - 1);
}
}
private:
M mutex;
boost::condition cond;
@@ -86,10 +85,12 @@ void do_test(M* dummy=0)
{
typedef buffer_t<M> buffer_type;
buffer_type::get_buffer();
boost::thread thrd1(&buffer_type::do_sender_thread);
boost::thread thrd1(&buffer_type::do_receiver_thread);
boost::thread thrd2(&buffer_type::do_receiver_thread);
boost::thread thrd3(&buffer_type::do_sender_thread);
thrd1.join();
thrd2.join();
thrd3.join();
}
void test_buffer()

BIN
example/monitor/monitor.mcp Normal file

Binary file not shown.

View File

@@ -0,0 +1 @@
/*

View File

@@ -7,124 +7,124 @@
namespace
{
boost::mutex iomx;
};
boost::mutex iomx;
}
class canteen
{
public:
canteen() : m_chickens(0) { }
canteen() : m_chickens(0) { }
void get(int id)
{
boost::mutex::scoped_lock lock(m_mutex);
while (m_chickens == 0)
{
{
boost::mutex::scoped_lock lock(iomx);
std::cout << "(" << clock() << ") Phil" << id <<
": wot, no chickens? I'll WAIT ..." << std::endl;
}
m_condition.wait(lock);
}
{
boost::mutex::scoped_lock lock(iomx);
std::cout << "(" << clock() << ") Phil" << id <<
": those chickens look good ... one please ..." << std::endl;
}
m_chickens--;
}
void put(int value)
{
boost::mutex::scoped_lock lock(m_mutex);
{
boost::mutex::scoped_lock lock(iomx);
std::cout << "(" << clock() <<
") Chef: ouch ... make room ... this dish is very hot ..." << std::endl;
}
void get(int id)
{
boost::mutex::scoped_lock lock(m_mutex);
while (m_chickens == 0)
{
{
boost::mutex::scoped_lock lock(iomx);
std::cout << "(" << clock() << ") Phil" << id <<
": wot, no chickens? I'll WAIT ..." << std::endl;
}
m_condition.wait(lock);
}
{
boost::mutex::scoped_lock lock(iomx);
std::cout << "(" << clock() << ") Phil" << id <<
": those chickens look good ... one please ..." << std::endl;
}
m_chickens--;
}
void put(int value)
{
boost::mutex::scoped_lock lock(m_mutex);
{
boost::mutex::scoped_lock lock(iomx);
std::cout << "(" << clock() <<
") Chef: ouch ... make room ... this dish is very hot ..." << std::endl;
}
boost::xtime xt;
boost::xtime_get(&xt, boost::TIME_UTC);
xt.sec += 3;
boost::thread::sleep(xt);
m_chickens += value;
{
boost::mutex::scoped_lock lock(iomx);
std::cout << "(" << clock() <<
") Chef: more chickens ... " << m_chickens <<
" now available ... NOTIFYING ..." << std::endl;
}
m_condition.notify_all();
}
m_chickens += value;
{
boost::mutex::scoped_lock lock(iomx);
std::cout << "(" << clock() <<
") Chef: more chickens ... " << m_chickens <<
" now available ... NOTIFYING ..." << std::endl;
}
m_condition.notify_all();
}
private:
boost::mutex m_mutex;
boost::condition m_condition;
int m_chickens;
boost::mutex m_mutex;
boost::condition m_condition;
int m_chickens;
};
canteen g_canteen;
void chef()
{
const int chickens = 4;
{
boost::mutex::scoped_lock lock(iomx);
std::cout << "(" << clock() << ") Chef: starting ..." << std::endl;
}
for (;;)
{
{
boost::mutex::scoped_lock lock(iomx);
std::cout << "(" << clock() << ") Chef: cooking ..." << std::endl;
}
const int chickens = 4;
{
boost::mutex::scoped_lock lock(iomx);
std::cout << "(" << clock() << ") Chef: starting ..." << std::endl;
}
for (;;)
{
{
boost::mutex::scoped_lock lock(iomx);
std::cout << "(" << clock() << ") Chef: cooking ..." << std::endl;
}
boost::xtime xt;
boost::xtime_get(&xt, boost::TIME_UTC);
xt.sec += 2;
boost::thread::sleep(xt);
{
boost::mutex::scoped_lock lock(iomx);
std::cout << "(" << clock() << ") Chef: " << chickens
<< " chickens, ready-to-go ..." << std::endl;
}
g_canteen.put(chickens);
}
{
boost::mutex::scoped_lock lock(iomx);
std::cout << "(" << clock() << ") Chef: " << chickens
<< " chickens, ready-to-go ..." << std::endl;
}
g_canteen.put(chickens);
}
}
struct phil
{
phil(int id) : m_id(id) { }
phil(int id) : m_id(id) { }
void run() {
{
boost::mutex::scoped_lock lock(iomx);
std::cout << "(" << clock() << ") Phil" << m_id << ": starting ..." << std::endl;
}
for (;;)
{
if (m_id > 0)
{
boost::mutex::scoped_lock lock(iomx);
std::cout << "(" << clock() << ") Phil" << m_id << ": starting ..." << std::endl;
}
for (;;)
{
if (m_id > 0)
{
boost::xtime xt;
boost::xtime_get(&xt, boost::TIME_UTC);
xt.sec += 3;
boost::thread::sleep(xt);
}
{
boost::mutex::scoped_lock lock(iomx);
std::cout << "(" << clock() << ") Phil" << m_id
<< ": gotta eat ..." << std::endl;
}
g_canteen.get(m_id);
{
boost::mutex::scoped_lock lock(iomx);
std::cout << "(" << clock() << ") Phil" << m_id
<< ": mmm ... that's good ..." << std::endl;
}
}
{
boost::mutex::scoped_lock lock(iomx);
std::cout << "(" << clock() << ") Phil" << m_id
<< ": gotta eat ..." << std::endl;
}
g_canteen.get(m_id);
{
boost::mutex::scoped_lock lock(iomx);
std::cout << "(" << clock() << ") Phil" << m_id
<< ": mmm ... that's good ..." << std::endl;
}
}
}
static void do_thread(void* param) {
static void do_thread(void* param) {
static_cast<phil*>(param)->run();
}
}
int m_id;
int m_id;
};
struct thread_adapt

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1
example/tennis/Carbon.r Normal file
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@@ -0,0 +1 @@
/*

View File

@@ -1,13 +1,12 @@
#include <boost/thread/mutex.hpp>
#include <boost/thread/condition.hpp>
#include <boost/thread/semaphore.hpp>
#include <boost/thread/thread.hpp>
#include <boost/thread/xtime.hpp>
#include <iostream>
#if defined(BOOST_HAS_WINTHREADS)
# include <windows.h>
# include <process.h>
# include <windows.h>
# include <process.h>
#endif
enum game_state

BIN
example/tennis/tennis.mcp Normal file

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View File

@@ -6,7 +6,7 @@
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. William E. Kempf makes no representations
// about the suitability of this software for any purpose.
// about the suitability of this software for any purpose.
// It is provided "as is" without express or implied warranty.
#ifndef BOOST_CONDITION_WEK070601_HPP
@@ -14,14 +14,17 @@
#include <boost/config.hpp>
#ifndef BOOST_HAS_THREADS
# error Thread support is unavailable!
# error Thread support is unavailable!
#endif
#include <boost/thread/exceptions.hpp>
#include <boost/utility.hpp>
#include <boost/thread/detail/lock.hpp>
#if defined(BOOST_HAS_PTHREADS)
# include <pthread.h>
#elif defined(BOOST_HAS_MPTASKS)
# include "scoped_critical_region.hpp"
#endif
namespace boost {
@@ -33,7 +36,7 @@ class condition : private noncopyable
public:
condition();
~condition();
void notify_one();
void notify_all();
@@ -42,7 +45,7 @@ public:
{
if (!lock)
throw lock_error();
do_wait(lock.m_mutex);
}
@@ -51,7 +54,7 @@ public:
{
if (!lock)
throw lock_error();
while (!pred())
do_wait(lock.m_mutex);
}
@@ -61,7 +64,7 @@ public:
{
if (!lock)
throw lock_error();
return do_timed_wait(lock.m_mutex, xt);
}
@@ -70,7 +73,7 @@ public:
{
if (!lock)
throw lock_error();
while (!pred())
{
if (!do_timed_wait(lock.m_mutex, xt))
@@ -84,46 +87,48 @@ private:
template <typename M>
void do_wait(M& mutex)
{
#if defined(BOOST_HAS_WINTHREADS)
#if (defined(BOOST_HAS_WINTHREADS) || defined(BOOST_HAS_MPTASKS))
enter_wait();
#endif
typename M::cv_state state;
mutex.do_unlock(state);
typedef typename detail::thread::lock_ops<M> lock_ops;
typename lock_ops::lock_state state;
lock_ops::unlock(mutex, state);
#if defined(BOOST_HAS_PTHREADS)
do_wait(state.pmutex);
#elif defined(BOOST_HAS_WINTHREADS)
#elif (defined(BOOST_HAS_WINTHREADS) || defined(BOOST_HAS_MPTASKS))
do_wait();
#endif
mutex.do_lock(state);
lock_ops::lock(mutex, state);
}
template <typename M>
bool do_timed_wait(M& mutex, const xtime& xt)
{
#if defined(BOOST_HAS_WINTHREADS)
#if (defined(BOOST_HAS_WINTHREADS) || defined(BOOST_HAS_MPTASKS))
enter_wait();
#endif
typename M::cv_state state;
mutex.do_unlock(state);
typedef typename detail::thread::lock_ops<M> lock_ops;
typename lock_ops::lock_state state;
lock_ops::unlock(mutex, state);
bool ret = false;
#if defined(BOOST_HAS_PTHREADS)
ret = do_timed_wait(xt, state.pmutex);
#elif defined(BOOST_HAS_WINTHREADS)
#elif (defined(BOOST_HAS_WINTHREADS) || defined(BOOST_HAS_MPTASKS))
ret = do_timed_wait(xt);
#endif
mutex.do_lock(state);
lock_ops::lock(mutex, state);
return ret;
}
#if defined(BOOST_HAS_WINTHREADS)
#if (defined(BOOST_HAS_WINTHREADS) || defined(BOOST_HAS_MPTASKS))
void enter_wait();
void do_wait();
bool do_timed_wait(const xtime& xt);
@@ -133,15 +138,24 @@ private:
#endif
#if defined(BOOST_HAS_WINTHREADS)
unsigned long m_gate;
unsigned long m_queue;
unsigned long m_mutex;
void* m_gate;
void* m_queue;
void* m_mutex;
unsigned m_gone; // # threads that timed out and never made it to the m_queue
unsigned long m_blocked; // # threads m_blocked m_waiting for the condition
unsigned m_waiting; // # threads m_waiting no longer m_waiting for the condition but still
// m_waiting to be removed from the m_queue
#elif defined(BOOST_HAS_PTHREADS)
pthread_cond_t m_condition;
#elif defined(BOOST_HAS_MPTASKS)
MPSemaphoreID m_gate;
MPSemaphoreID m_queue;
threads::mac::detail::scoped_critical_region m_mutex;
threads::mac::detail::scoped_critical_region m_mutex_mutex;
unsigned m_gone; // # threads that timed out and never made it to the m_queue
unsigned long m_blocked; // # threads m_blocked m_waiting for the condition
unsigned m_waiting; // # threads m_waiting no longer m_waiting for the condition but still
// m_waiting to be removed from the m_queue
#endif
};

View File

@@ -6,7 +6,7 @@
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. William E. Kempf makes no representations
// about the suitability of this software for any purpose.
// about the suitability of this software for any purpose.
// It is provided "as is" without express or implied warranty.
// This file is used to configure Boost.Threads during development

View File

@@ -0,0 +1,44 @@
// Copyright (C) 2001
// Mac Murrett
//
// Permission to use, copy, modify, distribute and sell this software
// and its documentation for any purpose is hereby granted without fee,
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. Mac Murrett makes no representations
// about the suitability of this software for any purpose. It is
// provided "as is" without express or implied warranty.
//
// See http://www.boost.org for most recent version including documentation.
#ifndef BOOST_FORCE_CAST_MJM012402_HPP
#define BOOST_FORCE_CAST_MJM012402_HPP
namespace boost {
namespace detail {
namespace thread {
// force_cast will convert anything to anything.
// general case
template<class Return_Type, class Argument_Type>
inline Return_Type &force_cast(Argument_Type &rSrc)
{ return(*reinterpret_cast<Return_Type *>(&rSrc)); }
// specialization for const
template<class Return_Type, class Argument_Type>
inline const Return_Type &force_cast(const Argument_Type &rSrc)
{ return(*reinterpret_cast<const Return_Type *>(&rSrc)); }
} // namespace thread
} // namespace detail
} // namespace boost
#endif // BOOST_FORCE_CAST_MJM012402_HPP

View File

@@ -6,7 +6,7 @@
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. William E. Kempf makes no representations
// about the suitability of this software for any purpose.
// about the suitability of this software for any purpose.
// It is provided "as is" without express or implied warranty.
#ifndef BOOST_XLOCK_WEK070601_HPP
@@ -22,12 +22,47 @@ struct xtime;
namespace detail { namespace thread {
template <typename Mutex>
class lock_ops : private noncopyable
{
private:
lock_ops() { }
public:
typedef typename Mutex::cv_state lock_state;
static void lock(Mutex& m)
{
m.do_lock();
}
static bool trylock(Mutex& m)
{
return m.do_trylock();
}
static bool timedlock(Mutex& m, const xtime& xt)
{
return m.do_timedlock(xt);
}
static void unlock(Mutex& m)
{
m.do_unlock();
}
static void lock(Mutex& m, lock_state& state)
{
m.do_lock(state);
}
static void unlock(Mutex& m, lock_state& state)
{
m.do_unlock(state);
}
};
template <typename Mutex>
class scoped_lock : private noncopyable
{
public:
typedef Mutex mutex_type;
explicit scoped_lock(Mutex& mx, bool initially_locked=true)
: m_mutex(mx), m_locked(false)
{
@@ -37,26 +72,26 @@ struct xtime;
{
if (m_locked) unlock();
}
void lock()
{
if (m_locked) throw lock_error();
m_mutex.do_lock();
lock_ops<Mutex>::lock(m_mutex);
m_locked = true;
}
void unlock()
{
if (!m_locked) throw lock_error();
m_mutex.do_unlock();
lock_ops<Mutex>::unlock(m_mutex);
m_locked = false;
}
bool locked() const { return m_locked; }
bool locked() const { return m_locked; }
operator const void*() const { return m_locked ? this : 0; }
private:
friend class boost::condition;
Mutex& m_mutex;
bool m_locked;
};
@@ -66,7 +101,7 @@ struct xtime;
{
public:
typedef TryMutex mutex_type;
explicit scoped_try_lock(TryMutex& mx)
: m_mutex(mx), m_locked(false)
{
@@ -81,31 +116,31 @@ struct xtime;
{
if (m_locked) unlock();
}
void lock()
{
if (m_locked) throw lock_error();
m_mutex.do_lock();
lock_ops<TryMutex>::lock(m_mutex);
m_locked = true;
}
bool try_lock()
{
if (m_locked) throw lock_error();
return (m_locked = m_mutex.do_trylock());
return (m_locked = lock_ops<TryMutex>::trylock(m_mutex));
}
void unlock()
{
if (!m_locked) throw lock_error();
m_mutex.do_unlock();
lock_ops<TryMutex>::unlock(m_mutex);
m_locked = false;
}
bool locked() const { return m_locked; }
bool locked() const { return m_locked; }
operator const void*() const { return m_locked ? this : 0; }
private:
friend class boost::condition;
TryMutex& m_mutex;
bool m_locked;
};
@@ -115,7 +150,7 @@ struct xtime;
{
public:
typedef TimedMutex mutex_type;
scoped_timed_lock(TimedMutex& mx, const xtime& xt)
: m_mutex(mx), m_locked(false)
{
@@ -130,31 +165,31 @@ struct xtime;
{
if (m_locked) unlock();
}
void lock()
{
if (m_locked) throw lock_error();
m_mutex.do_lock();
lock_ops<TimedMutex>::lock(m_mutex);
m_locked = true;
}
bool timed_lock(const xtime& xt)
{
if (m_locked) throw lock_error();
return (m_locked = m_mutex.do_timedlock(xt));
return (m_locked = lock_ops<TimedMutex>::timedlock(m_mutex, xt));
}
void unlock()
{
if (!m_locked) throw lock_error();
m_mutex.do_unlock();
lock_ops<TimedMutex>::unlock(m_mutex);
m_locked = false;
}
bool locked() const { return m_locked; }
bool locked() const { return m_locked; }
operator const void*() const { return m_locked ? this : 0; }
private:
friend class boost::condition;
TimedMutex& m_mutex;
bool m_locked;
};

View File

@@ -0,0 +1,64 @@
// Copyright (C) 2001
// Mac Murrett
//
// Permission to use, copy, modify, distribute and sell this software
// and its documentation for any purpose is hereby granted without fee,
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. Mac Murrett makes no representations
// about the suitability of this software for any purpose. It is
// provided "as is" without express or implied warranty.
//
// See http://www.boost.org for most recent version including documentation.
#ifndef BOOST_SINGLETON_MJM012402_HPP
#define BOOST_SINGLETON_MJM012402_HPP
namespace boost {
namespace detail {
namespace thread {
// class singleton has the same goal as all singletons: create one instance of a
// class on demand, then dish it out as requested.
template<class T>
class singleton: private T
{
private:
singleton();
~singleton();
public:
static T &instance();
};
template<class T>
inline singleton<T>::singleton()
{ /* no-op */ }
template<class T>
inline singleton<T>::~singleton()
{ /* no-op */ }
template<class T>
/*static*/ T &singleton<T>::instance()
{
// function-local static to force this to work correctly at static initialization
// time.
static singleton<T> s_oT;
return(s_oT);
}
} // namespace thread
} // namespace detail
} // namespace boost
#endif // BOOST_SINGLETON_MJM012402_HPP

View File

@@ -9,13 +9,6 @@
// about the suitability of this software for any purpose.
// It is provided "as is" without express or implied warranty.
// This file is used to configure Boost.Threads during development
// in order to decouple dependency on any Boost release. Once
// accepted into Boost these contents will be moved to <boost/config>
// or some other appropriate build configuration and all
// #include <boost/thread/config.hpp> statements will be changed
// accordingly.
#ifndef BOOST_THREAD_EXCEPTIONS_PDM070801_H
#define BOOST_THREAD_EXCEPTIONS_PDM070801_H
@@ -32,13 +25,13 @@ namespace boost {
class lock_error : public std::runtime_error
{
public:
lock_error() : std::runtime_error("thread lock error") { }
lock_error();
};
class thread_resource_error : public std::runtime_error
{
public:
thread_resource_error() : std::runtime_error("thread resource error") { }
thread_resource_error();
};
} // namespace boost

View File

@@ -6,7 +6,7 @@
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. William E. Kempf makes no representations
// about the suitability of this software for any purpose.
// about the suitability of this software for any purpose.
// It is provided "as is" without express or implied warranty.
#ifndef BOOST_MUTEX_WEK070601_HPP
@@ -14,7 +14,7 @@
#include <boost/config.hpp>
#ifndef BOOST_HAS_THREADS
# error Thread support is unavailable!
# error Thread support is unavailable!
#endif
#include <boost/utility.hpp>
@@ -24,22 +24,24 @@
# include <pthread.h>
#endif
#if defined(BOOST_HAS_MPTASKS)
# include "scoped_critical_region.hpp"
#endif
namespace boost {
class condition;
struct xtime;
class mutex : private noncopyable
{
public:
friend class detail::thread::scoped_lock<mutex>;
friend class condition;
friend class detail::thread::lock_ops<mutex>;
typedef detail::thread::scoped_lock<mutex> scoped_lock;
mutex();
~mutex();
private:
#if defined(BOOST_HAS_WINTHREADS)
typedef void* cv_state;
@@ -48,6 +50,10 @@ private:
{
pthread_mutex_t* pmutex;
};
#elif defined(BOOST_HAS_MPTASKS)
struct cv_state
{
};
#endif
void do_lock();
void do_unlock();
@@ -55,25 +61,26 @@ private:
void do_unlock(cv_state& state);
#if defined(BOOST_HAS_WINTHREADS)
unsigned long m_mutex;
void* m_mutex;
#elif defined(BOOST_HAS_PTHREADS)
pthread_mutex_t m_mutex;
#elif defined(BOOST_HAS_MPTASKS)
threads::mac::detail::scoped_critical_region m_mutex;
threads::mac::detail::scoped_critical_region m_mutex_mutex;
#endif
};
class try_mutex : private noncopyable
{
public:
friend class detail::thread::scoped_lock<try_mutex>;
friend class detail::thread::scoped_try_lock<try_mutex>;
friend class condition;
friend class detail::thread::lock_ops<try_mutex>;
typedef detail::thread::scoped_lock<try_mutex> scoped_lock;
typedef detail::thread::scoped_try_lock<try_mutex> scoped_try_lock;
try_mutex();
~try_mutex();
private:
#if defined(BOOST_HAS_WINTHREADS)
typedef void* cv_state;
@@ -82,6 +89,10 @@ private:
{
pthread_mutex_t* pmutex;
};
#elif defined(BOOST_HAS_MPTASKS)
struct cv_state
{
};
#endif
void do_lock();
bool do_trylock();
@@ -90,27 +101,27 @@ private:
void do_unlock(cv_state& state);
#if defined(BOOST_HAS_WINTHREADS)
unsigned long m_mutex;
void* m_mutex;
#elif defined(BOOST_HAS_PTHREADS)
pthread_mutex_t m_mutex;
#elif defined(BOOST_HAS_MPTASKS)
threads::mac::detail::scoped_critical_region m_mutex;
threads::mac::detail::scoped_critical_region m_mutex_mutex;
#endif
};
class timed_mutex : private noncopyable
{
public:
friend class detail::thread::scoped_lock<timed_mutex>;
friend class detail::thread::scoped_try_lock<timed_mutex>;
friend class detail::thread::scoped_timed_lock<timed_mutex>;
friend class condition;
friend class detail::thread::lock_ops<timed_mutex>;
typedef detail::thread::scoped_lock<timed_mutex> scoped_lock;
typedef detail::thread::scoped_try_lock<timed_mutex> scoped_try_lock;
typedef detail::thread::scoped_timed_lock<timed_mutex> scoped_timed_lock;
timed_mutex();
~timed_mutex();
private:
#if defined(BOOST_HAS_WINTHREADS)
typedef void* cv_state;
@@ -119,6 +130,10 @@ private:
{
pthread_mutex_t* pmutex;
};
#elif defined(BOOST_HAS_MPTASKS)
struct cv_state
{
};
#endif
void do_lock();
bool do_trylock();
@@ -126,13 +141,16 @@ private:
void do_unlock();
void do_lock(cv_state& state);
void do_unlock(cv_state& state);
#if defined(BOOST_HAS_WINTHREADS)
unsigned long m_mutex;
void* m_mutex;
#elif defined(BOOST_HAS_PTHREADS)
pthread_mutex_t m_mutex;
pthread_cond_t m_condition;
bool m_locked;
#elif defined(BOOST_HAS_MPTASKS)
threads::mac::detail::scoped_critical_region m_mutex;
threads::mac::detail::scoped_critical_region m_mutex_mutex;
#endif
};

View File

@@ -6,7 +6,7 @@
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. William E. Kempf makes no representations
// about the suitability of this software for any purpose.
// about the suitability of this software for any purpose.
// It is provided "as is" without express or implied warranty.
#ifndef BOOST_ONCE_WEK080101_HPP
@@ -14,7 +14,7 @@
#include <boost/config.hpp>
#ifndef BOOST_HAS_THREADS
# error Thread support is unavailable!
# error Thread support is unavailable!
#endif
#if defined(BOOST_HAS_PTHREADS)
@@ -26,12 +26,12 @@ namespace boost {
#if defined(BOOST_HAS_PTHREADS)
typedef pthread_once_t once_flag;
const once_flag once_init = PTHREAD_ONCE_INIT;
#define BOOST_ONCE_INIT PTHREAD_ONCE_INIT
#elif defined(BOOST_HAS_WINTHREADS)
#elif (defined(BOOST_HAS_WINTHREADS) || defined(BOOST_HAS_MPTASKS))
typedef bool once_flag;
const once_flag once_init = false;
#define BOOST_ONCE_INIT false
#endif

View File

@@ -6,7 +6,7 @@
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. William E. Kempf makes no representations
// about the suitability of this software for any purpose.
// about the suitability of this software for any purpose.
// It is provided "as is" without express or implied warranty.
#ifndef BOOST_RECURSIVE_MUTEX_WEK070601_HPP
@@ -14,7 +14,7 @@
#include <boost/config.hpp>
#ifndef BOOST_HAS_THREADS
# error Thread support is unavailable!
# error Thread support is unavailable!
#endif
#include <boost/utility.hpp>
@@ -22,26 +22,26 @@
#if defined(BOOST_HAS_PTHREADS)
# include <pthread.h>
#elif defined(BOOST_HAS_MPTASKS)
# include "scoped_critical_region.hpp"
#endif
namespace boost {
class condition;
struct xtime;
class recursive_mutex : private noncopyable
{
public:
friend class detail::thread::scoped_lock<recursive_mutex>;
friend class condition;
friend class detail::thread::lock_ops<recursive_mutex>;
typedef detail::thread::scoped_lock<recursive_mutex> scoped_lock;
recursive_mutex();
~recursive_mutex();
private:
#if defined(BOOST_HAS_WINTHREADS)
#if (defined(BOOST_HAS_WINTHREADS) || defined(BOOST_HAS_MPTASKS))
typedef std::size_t cv_state;
#elif defined(BOOST_HAS_PTHREADS)
struct cv_state
@@ -56,7 +56,7 @@ private:
void do_unlock(cv_state& state);
#if defined(BOOST_HAS_WINTHREADS)
unsigned long m_mutex;
void* m_mutex;
unsigned long m_count;
#elif defined(BOOST_HAS_PTHREADS)
pthread_mutex_t m_mutex;
@@ -66,24 +66,26 @@ private:
pthread_t m_thread_id;
bool m_valid_id;
# endif
#elif defined(BOOST_HAS_MPTASKS)
threads::mac::detail::scoped_critical_region m_mutex;
threads::mac::detail::scoped_critical_region m_mutex_mutex;
std::size_t m_count;
#endif
};
class recursive_try_mutex : private noncopyable
{
public:
friend class detail::thread::scoped_lock<recursive_try_mutex>;
friend class detail::thread::scoped_try_lock<recursive_try_mutex>;
friend class condition;
friend class detail::thread::lock_ops<recursive_try_mutex>;
typedef detail::thread::scoped_lock<recursive_try_mutex> scoped_lock;
typedef detail::thread::scoped_try_lock<recursive_try_mutex> scoped_try_lock;
recursive_try_mutex();
~recursive_try_mutex();
private:
#if defined(BOOST_HAS_WINTHREADS)
#if (defined(BOOST_HAS_WINTHREADS) || defined(BOOST_HAS_MPTASKS))
typedef std::size_t cv_state;
#elif defined(BOOST_HAS_PTHREADS)
struct cv_state
@@ -97,9 +99,9 @@ private:
void do_unlock();
void do_lock(cv_state& state);
void do_unlock(cv_state& state);
#if defined(BOOST_HAS_WINTHREADS)
unsigned long m_mutex;
void* m_mutex;
unsigned long m_count;
#elif defined(BOOST_HAS_PTHREADS)
pthread_mutex_t m_mutex;
@@ -109,26 +111,27 @@ private:
pthread_t m_thread_id;
bool m_valid_id;
# endif
#elif defined(BOOST_HAS_MPTASKS)
threads::mac::detail::scoped_critical_region m_mutex;
threads::mac::detail::scoped_critical_region m_mutex_mutex;
std::size_t m_count;
#endif
};
class recursive_timed_mutex : private noncopyable
{
public:
friend class detail::thread::scoped_lock<recursive_timed_mutex>;
friend class detail::thread::scoped_try_lock<recursive_timed_mutex>;
friend class detail::thread::scoped_timed_lock<recursive_timed_mutex>;
friend class condition;
friend class detail::thread::lock_ops<recursive_timed_mutex>;
typedef detail::thread::scoped_lock<recursive_timed_mutex> scoped_lock;
typedef detail::thread::scoped_try_lock<recursive_timed_mutex> scoped_try_lock;
typedef detail::thread::scoped_timed_lock<recursive_timed_mutex> scoped_timed_lock;
recursive_timed_mutex();
~recursive_timed_mutex();
private:
#if defined(BOOST_HAS_WINTHREADS)
#if (defined(BOOST_HAS_WINTHREADS) || defined(BOOST_HAS_MPTASKS))
typedef std::size_t cv_state;
#elif defined(BOOST_HAS_PTHREADS)
struct cv_state
@@ -143,9 +146,9 @@ private:
void do_unlock();
void do_lock(cv_state& state);
void do_unlock(cv_state& state);
#if defined(BOOST_HAS_WINTHREADS)
unsigned long m_mutex;
void* m_mutex;
unsigned long m_count;
#elif defined(BOOST_HAS_PTHREADS)
pthread_mutex_t m_mutex;
@@ -153,6 +156,10 @@ private:
pthread_t m_thread_id;
bool m_valid_id;
unsigned m_count;
#elif defined(BOOST_HAS_MPTASKS)
threads::mac::detail::scoped_critical_region m_mutex;
threads::mac::detail::scoped_critical_region m_mutex_mutex;
std::size_t m_count;
#endif
};

View File

@@ -1,57 +0,0 @@
// Copyright (C) 2001
// William E. Kempf
//
// Permission to use, copy, modify, distribute and sell this software
// and its documentation for any purpose is hereby granted without fee,
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. William E. Kempf makes no representations
// about the suitability of this software for any purpose.
// It is provided "as is" without express or implied warranty.
#ifndef BOOST_SEMAPHORE_WEK070601_HPP
#define BOOST_SEMAPHORE_WEK070601_HPP
#include <boost/config.hpp>
#ifndef BOOST_HAS_THREADS
# error Thread support is unavailable!
#endif
#include <boost/utility.hpp>
#if defined(BOOST_HAS_PTHREADS)
# include <pthread.h>
#endif
namespace boost {
struct xtime;
class semaphore : private noncopyable
{
public:
explicit semaphore(unsigned count=0, unsigned max=0);
~semaphore();
bool up(unsigned count=1, unsigned* prev=0);
void down();
bool down(const xtime& xt);
private:
#if defined(BOOST_HAS_WINTHREADS)
unsigned long m_sema;
#elif defined(BOOST_HAS_PTHREADS)
pthread_mutex_t m_mutex;
pthread_cond_t m_condition;
unsigned m_available;
unsigned m_max;
#endif
};
} // namespace boost
// Change Log:
// 8 Feb 01 WEKEMPF Initial version.
// 22 May 01 WEKEMPF Modified to use xtime for time outs.
#endif // BOOST_SEMAPHORE_WEK070601_HPP

View File

@@ -6,7 +6,7 @@
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. William E. Kempf makes no representations
// about the suitability of this software for any purpose.
// about the suitability of this software for any purpose.
// It is provided "as is" without express or implied warranty.
#ifndef BOOST_THREAD_WEK070601_HPP
@@ -14,7 +14,7 @@
#include <boost/config.hpp>
#ifndef BOOST_HAS_THREADS
# error Thread support is unavailable!
# error Thread support is unavailable!
#endif
#include <boost/utility.hpp>
@@ -26,6 +26,8 @@
#if defined(BOOST_HAS_PTHREADS)
# include <pthread.h>
# include <boost/thread/condition.hpp>
#elif defined(BOOST_HAS_MPTASKS)
# include <Multiprocessing.h>
#endif
namespace boost {
@@ -49,11 +51,14 @@ public:
private:
#if defined(BOOST_HAS_WINTHREADS)
unsigned long m_thread;
void* m_thread;
unsigned int m_id;
#elif defined(BOOST_HAS_PTHREADS)
private:
pthread_t m_thread;
#elif defined(BOOST_HAS_MPTASKS)
MPQueueID m_pJoinQueueID;
MPTaskID m_pTaskID;
#endif
bool m_joinable;
};

View File

@@ -6,7 +6,7 @@
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. William E. Kempf makes no representations
// about the suitability of this software for any purpose.
// about the suitability of this software for any purpose.
// It is provided "as is" without express or implied warranty.
#ifndef BOOST_TSS_WEK070601_HPP
@@ -14,13 +14,15 @@
#include <boost/config.hpp>
#ifndef BOOST_HAS_THREADS
# error Thread support is unavailable!
# error Thread support is unavailable!
#endif
#include <boost/utility.hpp>
#if defined(BOOST_HAS_PTHREADS)
# include <pthread.h>
#elif defined(BOOST_HAS_MPTASKS)
# include <Multiprocessing.h>
#endif
namespace boost {
@@ -41,8 +43,15 @@ namespace boost {
void (*m_cleanup)(void*);
#elif defined(BOOST_HAS_PTHREADS)
pthread_key_t m_key;
#elif defined(BOOST_HAS_MPTASKS)
TaskStorageIndex m_key;
void (*m_cleanup)(void*);
#endif
};
#if defined(BOOST_HAS_MPTASKS)
void thread_cleanup();
#endif
}
template <typename T>

View File

@@ -6,7 +6,7 @@
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. William E. Kempf makes no representations
// about the suitability of this software for any purpose.
// about the suitability of this software for any purpose.
// It is provided "as is" without express or implied warranty.
#ifndef BOOST_XTIME_WEK070601_HPP

View File

@@ -1,80 +0,0 @@
/*
*
* Copyright (C) 2001
* William E. Kempf
*
* Permission to use, copy, modify, distribute and sell this software
* and its documentation for any purpose is hereby granted without fee,
* provided that the above copyright notice appear in all copies and
* that both that copyright notice and this permission notice appear
* in supporting documentation. William E. Kempf makes no representations
* about the suitability of this software for any purpose.
* It is provided "as is" without express or implied warranty.
*
* Revision History (excluding minor changes for specific compilers)
* 8 Feb 01 Initial version.
*/
#include <boost/thread/atomic.hpp>
#if defined(BOOST_HAS_WINTHREADS)
# include <windows.h>
#endif
namespace boost {
atomic_t::value_type read(const atomic_t& x)
{
return x._value;
}
#if defined(BOOST_HAS_WINTHREADS)
atomic_t::value_type increment(atomic_t& x)
{
return InterlockedIncrement(const_cast<long*>(&x._value));
}
atomic_t::value_type decrement(atomic_t& x)
{
return InterlockedDecrement(const_cast<long*>(&x._value));
}
atomic_t::value_type swap(atomic_t& x, atomic_t::value_type y)
{
return InterlockedExchange(const_cast<long*>(&x._value), y);
}
atomic_t::value_type compare_swap(atomic_t& x, atomic_t::value_type y, atomic_t::value_type z)
{
return InterlockedCompareExchange(const_cast<long*>(&x._value), y, z);
}
#else
atomic_t::value_type increment(atomic_t& x)
{
mutex::lock lock(x._mutex);
return ++x._value;
}
atomic_t::value_type decrement(atomic_t& x)
{
mutex::lock lock(x._mutex);
return --x._value;
}
atomic_t::value_type swap(atomic_t& x, atomic_t::value_type y)
{
mutex::lock lock(x._mutex);
atomic_t::value_type temp = x._value;
x._value = y;
return temp;
}
atomic_t::value_type compare_swap(atomic_t& x, atomic_t::value_type y, atomic_t::value_type z)
{
mutex::lock lock(x._mutex);
atomic_t::value_type temp = x._value;
if (temp == z)
x._value = y;
return temp;
}
#endif
} // namespace boost

View File

@@ -6,22 +6,28 @@
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. William E. Kempf makes no representations
// about the suitability of this software for any purpose.
// about the suitability of this software for any purpose.
// It is provided "as is" without express or implied warranty.
#include <boost/thread/condition.hpp>
#include <boost/thread/xtime.hpp>
#include <boost/thread/thread.hpp>
#include <boost/thread/thread.hpp>
#include <boost/thread/exceptions.hpp>
#include <boost/limits.hpp>
#include <cassert>
#include "timeconv.inl"
#if defined(BOOST_HAS_WINTHREADS)
# define NOMINMAX
# ifndef NOMINMAX
# define NOMINMAX
# endif
# include <windows.h>
#elif defined(BOOST_HAS_PTHREADS)
# include <errno.h>
#elif defined(BOOST_HAS_MPTASKS)
# include <MacErrors.h>
# include "mac/init.hpp"
# include "mac/safe.hpp"
#endif
namespace boost {
@@ -30,28 +36,28 @@ namespace boost {
condition::condition()
: m_gone(0), m_blocked(0), m_waiting(0)
{
m_gate = reinterpret_cast<unsigned long>(CreateSemaphore(0, 1, 1, 0));
m_queue = reinterpret_cast<unsigned long>(CreateSemaphore(0, 0, std::numeric_limits<long>::max(), 0));
m_mutex = reinterpret_cast<unsigned long>(CreateMutex(0, 0, 0));
m_gate = reinterpret_cast<void*>(CreateSemaphore(0, 1, 1, 0));
m_queue = reinterpret_cast<void*>(CreateSemaphore(0, 0, std::numeric_limits<long>::max(), 0));
m_mutex = reinterpret_cast<void*>(CreateMutex(0, 0, 0));
if (!m_gate || !m_queue || !m_mutex)
{
int res = 0;
if (m_gate)
{
res = CloseHandle(reinterpret_cast<HANDLE>(m_gate));
assert(res);
}
if (m_queue)
{
res = CloseHandle(reinterpret_cast<HANDLE>(m_queue));
assert(res);
}
if (m_mutex)
{
res = CloseHandle(reinterpret_cast<HANDLE>(m_mutex));
assert(res);
}
if (m_gate)
{
res = CloseHandle(reinterpret_cast<HANDLE>(m_gate));
assert(res);
}
if (m_queue)
{
res = CloseHandle(reinterpret_cast<HANDLE>(m_queue));
assert(res);
}
if (m_mutex)
{
res = CloseHandle(reinterpret_cast<HANDLE>(m_mutex));
assert(res);
}
throw thread_resource_error();
}
@@ -87,6 +93,7 @@ void condition::notify_one()
++m_waiting;
--m_blocked;
signals = 1;
}
else
{
@@ -107,15 +114,15 @@ void condition::notify_one()
res = ReleaseSemaphore(reinterpret_cast<HANDLE>(m_gate), 1, 0);
assert(res);
}
}
res = ReleaseMutex(reinterpret_cast<HANDLE>(m_mutex));
res = ReleaseMutex(reinterpret_cast<HANDLE>(m_mutex));
assert(res);
if (signals)
{
res = ReleaseSemaphore(reinterpret_cast<HANDLE>(m_queue), signals, 0);
assert(res);
if (signals)
{
res = ReleaseSemaphore(reinterpret_cast<HANDLE>(m_queue), signals, 0);
assert(res);
}
}
}
@@ -185,7 +192,7 @@ void condition::do_wait()
int res = 0;
res = WaitForSingleObject(reinterpret_cast<HANDLE>(m_queue), INFINITE);
assert(res == WAIT_OBJECT_0);
unsigned was_waiting=0;
unsigned was_gone=0;
@@ -240,12 +247,12 @@ bool condition::do_timed_wait(const xtime& xt)
unsigned milliseconds;
to_duration(xt, milliseconds);
int res = 0;
unsigned int res = 0;
res = WaitForSingleObject(reinterpret_cast<HANDLE>(m_queue), milliseconds);
assert(res != WAIT_FAILED && res != WAIT_ABANDONED);
bool ret = (res == WAIT_OBJECT_0);
unsigned was_waiting=0;
unsigned was_gone=0;
@@ -351,6 +358,285 @@ bool condition::do_timed_wait(const xtime& xt, pthread_mutex_t* pmutex)
return res != ETIMEDOUT;
}
#elif defined(BOOST_HAS_MPTASKS)
using threads::mac::detail::safe_enter_critical_region;
using threads::mac::detail::safe_wait_on_semaphore;
condition::condition()
: m_gone(0), m_blocked(0), m_waiting(0)
{
threads::mac::detail::thread_init();
OSStatus lStatus = noErr;
lStatus = MPCreateSemaphore(1, 1, &m_gate);
if(lStatus == noErr)
lStatus = MPCreateSemaphore(ULONG_MAX, 0, &m_queue);
if(lStatus != noErr || !m_gate || !m_queue)
{
if (m_gate)
{
lStatus = MPDeleteSemaphore(m_gate);
assert(lStatus == noErr);
}
if (m_queue)
{
lStatus = MPDeleteSemaphore(m_queue);
assert(lStatus == noErr);
}
throw thread_resource_error();
}
}
condition::~condition()
{
OSStatus lStatus = noErr;
lStatus = MPDeleteSemaphore(m_gate);
assert(lStatus == noErr);
lStatus = MPDeleteSemaphore(m_queue);
assert(lStatus == noErr);
}
void condition::notify_one()
{
unsigned signals = 0;
OSStatus lStatus = noErr;
lStatus = safe_enter_critical_region(m_mutex, kDurationForever, m_mutex_mutex);
assert(lStatus == noErr);
if (m_waiting != 0) // the m_gate is already closed
{
if (m_blocked == 0)
{
lStatus = MPExitCriticalRegion(m_mutex);
assert(lStatus == noErr);
return;
}
++m_waiting;
--m_blocked;
}
else
{
lStatus = safe_wait_on_semaphore(m_gate, kDurationForever);
assert(lStatus == noErr);
if (m_blocked > m_gone)
{
if (m_gone != 0)
{
m_blocked -= m_gone;
m_gone = 0;
}
signals = m_waiting = 1;
--m_blocked;
}
else
{
lStatus = MPSignalSemaphore(m_gate);
assert(lStatus == noErr);
}
lStatus = MPExitCriticalRegion(m_mutex);
assert(lStatus == noErr);
while (signals)
{
lStatus = MPSignalSemaphore(m_queue);
assert(lStatus == noErr);
--signals;
}
}
}
void condition::notify_all()
{
unsigned signals = 0;
OSStatus lStatus = noErr;
lStatus = safe_enter_critical_region(m_mutex, kDurationForever, m_mutex_mutex);
assert(lStatus == noErr);
if (m_waiting != 0) // the m_gate is already closed
{
if (m_blocked == 0)
{
lStatus = MPExitCriticalRegion(m_mutex);
assert(lStatus == noErr);
return;
}
m_waiting += (signals = m_blocked);
m_blocked = 0;
}
else
{
lStatus = safe_wait_on_semaphore(m_gate, kDurationForever);
assert(lStatus == noErr);
if (m_blocked > m_gone)
{
if (m_gone != 0)
{
m_blocked -= m_gone;
m_gone = 0;
}
signals = m_waiting = m_blocked;
m_blocked = 0;
}
else
{
lStatus = MPSignalSemaphore(m_gate);
assert(lStatus == noErr);
}
lStatus = MPExitCriticalRegion(m_mutex);
assert(lStatus == noErr);
while (signals)
{
lStatus = MPSignalSemaphore(m_queue);
assert(lStatus == noErr);
--signals;
}
}
}
void condition::enter_wait()
{
OSStatus lStatus = noErr;
lStatus = safe_wait_on_semaphore(m_gate, kDurationForever);
assert(lStatus == noErr);
++m_blocked;
lStatus = MPSignalSemaphore(m_gate);
assert(lStatus == noErr);
}
void condition::do_wait()
{
OSStatus lStatus = noErr;
lStatus = safe_wait_on_semaphore(m_queue, kDurationForever);
assert(lStatus == noErr);
unsigned was_waiting=0;
unsigned was_gone=0;
lStatus = safe_enter_critical_region(m_mutex, kDurationForever, m_mutex_mutex);
assert(lStatus == noErr);
was_waiting = m_waiting;
was_gone = m_gone;
if (was_waiting != 0)
{
if (--m_waiting == 0)
{
if (m_blocked != 0)
{
lStatus = MPSignalSemaphore(m_gate); // open m_gate
assert(lStatus == noErr);
was_waiting = 0;
}
else if (m_gone != 0)
m_gone = 0;
}
}
else if (++m_gone == (std::numeric_limits<unsigned>::max() / 2))
{
// timeout occured, normalize the m_gone count
// this may occur if many calls to wait with a timeout are made and
// no call to notify_* is made
lStatus = safe_wait_on_semaphore(m_gate, kDurationForever);
assert(lStatus == noErr);
m_blocked -= m_gone;
lStatus = MPSignalSemaphore(m_gate);
assert(lStatus == noErr);
m_gone = 0;
}
lStatus = MPExitCriticalRegion(m_mutex);
assert(lStatus == noErr);
if (was_waiting == 1)
{
for (/**/ ; was_gone; --was_gone)
{
// better now than spurious later
lStatus = safe_wait_on_semaphore(m_queue, kDurationForever);
assert(lStatus == noErr);
}
lStatus = MPSignalSemaphore(m_gate);
assert(lStatus == noErr);
}
}
bool condition::do_timed_wait(const xtime& xt)
{
unsigned milliseconds;
to_duration(xt, milliseconds);
OSStatus lStatus = noErr;
lStatus = safe_wait_on_semaphore(m_queue, milliseconds);
assert(lStatus == noErr || lStatus == kMPTimeoutErr);
bool ret = (lStatus == noErr);
unsigned was_waiting=0;
unsigned was_gone=0;
lStatus = safe_enter_critical_region(m_mutex, kDurationForever, m_mutex_mutex);
assert(lStatus == noErr);
was_waiting = m_waiting;
was_gone = m_gone;
if (was_waiting != 0)
{
if (!ret) // timeout
{
if (m_blocked != 0)
--m_blocked;
else
++m_gone; // count spurious wakeups
}
if (--m_waiting == 0)
{
if (m_blocked != 0)
{
lStatus = MPSignalSemaphore(m_gate); // open m_gate
assert(lStatus == noErr);
was_waiting = 0;
}
else if (m_gone != 0)
m_gone = 0;
}
}
else if (++m_gone == (std::numeric_limits<unsigned>::max() / 2))
{
// timeout occured, normalize the m_gone count
// this may occur if many calls to wait with a timeout are made and
// no call to notify_* is made
lStatus = safe_wait_on_semaphore(m_gate, kDurationForever);
assert(lStatus == noErr);
m_blocked -= m_gone;
lStatus = MPSignalSemaphore(m_gate);
assert(lStatus == noErr);
m_gone = 0;
}
lStatus = MPExitCriticalRegion(m_mutex);
assert(lStatus == noErr);
if (was_waiting == 1)
{
for (/**/ ; was_gone; --was_gone)
{
// better now than spurious later
lStatus = safe_wait_on_semaphore(m_queue, kDurationForever);
assert(lStatus == noErr);
}
lStatus = MPSignalSemaphore(m_gate);
assert(lStatus == noErr);
}
return ret;
}
#endif
} // namespace boost

25
src/exceptions.cpp Normal file
View File

@@ -0,0 +1,25 @@
// Copyright (C) 2001
// William E. Kempf
//
// Permission to use, copy, modify, distribute and sell this software
// and its documentation for any purpose is hereby granted without fee,
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. William E. Kempf makes no representations
// about the suitability of this software for any purpose.
// It is provided "as is" without express or implied warranty.
#include <boost/thread/exceptions.hpp>
#include <string>
namespace boost {
lock_error::lock_error() : std::runtime_error("thread lock error")
{
}
thread_resource_error::thread_resource_error() : std::runtime_error("thread resource error")
{
}
} // namespace boost

14
src/mac/debug_prefix.hpp Normal file
View File

@@ -0,0 +1,14 @@
// Copyright (C) 2001
// Mac Murrett
//
// Permission to use, copy, modify, distribute and sell this software
// and its documentation for any purpose is hereby granted without fee,
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. Mac Murrett makes no representations
// about the suitability of this software for any purpose. It is
// provided "as is" without express or implied warranty.
//
// See http://www.boost.org for most recent version including documentation.
#define TARGET_CARBON 1

72
src/mac/delivery_man.cpp Normal file
View File

@@ -0,0 +1,72 @@
// Copyright (C) 2001
// Mac Murrett
//
// Permission to use, copy, modify, distribute and sell this software
// and its documentation for any purpose is hereby granted without fee,
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. Mac Murrett makes no representations
// about the suitability of this software for any purpose. It is
// provided "as is" without express or implied warranty.
//
// See http://www.boost.org for most recent version including documentation.
#include "delivery_man.hpp"
#include "os.hpp"
#include "execution_context.hpp"
namespace boost {
namespace threads {
namespace mac {
namespace detail {
delivery_man::delivery_man():
m_pPackage(NULL),
m_pSemaphore(kInvalidID),
m_bPackageWaiting(false)
{
assert(at_st());
OSStatus lStatus = MPCreateSemaphore(1UL, 0UL, &m_pSemaphore);
// TODO - throw on error here
assert(lStatus == noErr);
}
delivery_man::~delivery_man()
{
assert(m_bPackageWaiting == false);
OSStatus lStatus = MPDeleteSemaphore(m_pSemaphore);
assert(lStatus == noErr);
}
void delivery_man::accept_deliveries()
{
if(m_bPackageWaiting)
{
assert(m_pPackage != NULL);
m_pPackage->accept();
m_pPackage = NULL;
m_bPackageWaiting = false;
// signal to the thread making the call that we're done
OSStatus lStatus = MPSignalSemaphore(m_pSemaphore);
assert(lStatus == noErr);
}
}
} // namespace detail
} // namespace mac
} // namespace threads
} // namespace boost

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// Copyright (C) 2001
// Mac Murrett
//
// Permission to use, copy, modify, distribute and sell this software
// and its documentation for any purpose is hereby granted without fee,
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. Mac Murrett makes no representations
// about the suitability of this software for any purpose. It is
// provided "as is" without express or implied warranty.
//
// See http://www.boost.org for most recent version including documentation.
#ifndef BOOST_DELIVERY_MAN_MJM012402_HPP
#define BOOST_DELIVERY_MAN_MJM012402_HPP
#include <boost/function.hpp>
#include <boost/utility.hpp>
#include <boost/thread/mutex.hpp>
#include "package.hpp"
#include <Multiprocessing.h>
namespace boost {
namespace threads {
namespace mac {
namespace detail {
// class delivery_man is intended to move boost::function objects from MP tasks to
// other execution contexts (such as deferred task time or system task time).
class delivery_man: private noncopyable
{
public:
delivery_man();
~delivery_man();
public:
template<class R>
R deliver(function<R> &rFunctor);
void accept_deliveries();
private:
base_package *m_pPackage;
mutex m_oMutex;
MPSemaphoreID m_pSemaphore;
bool m_bPackageWaiting;
};
template<class R>
R delivery_man::deliver(function<R> &rFunctor)
{
assert(at_mp());
// lock our mutex
mutex::scoped_lock oLock(m_oMutex);
// create a package and save it
package<R> oPackage(rFunctor);
m_pPackage = &oPackage;
m_bPackageWaiting = true;
// wait on the semaphore
OSStatus lStatus = MPWaitOnSemaphore(m_pSemaphore, kDurationForever);
assert(lStatus == noErr);
return(oPackage.return_value());
}
} // namespace detail
} // namespace mac
} // namespace threads
} // namespace boost
#endif // BOOST_DELIVERY_MAN_MJM012402_HPP

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// Copyright (C) 2001
// Mac Murrett
//
// Permission to use, copy, modify, distribute and sell this software
// and its documentation for any purpose is hereby granted without fee,
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. Mac Murrett makes no representations
// about the suitability of this software for any purpose. It is
// provided "as is" without express or implied warranty.
//
// See http://www.boost.org for most recent version including documentation.
#include "dt_scheduler.hpp"
#include "ot_context.hpp"
#include <boost/thread/detail/singleton.hpp>
#include <OpenTransportProtocol.h>
namespace boost {
namespace threads {
namespace mac {
namespace detail {
const OTTimeout k_ulTimerTaskDelay = 1UL;
dt_scheduler::dt_scheduler():
m_bReschedule(false),
m_uppTask(NULL),
m_lTask(0UL)
{
using ::boost::detail::thread::singleton;
ot_context &rContext(singleton<ot_context>::instance());
m_uppTask = NewOTProcessUPP(task_entry);
m_lTask = OTCreateTimerTaskInContext(m_uppTask, this, rContext.get_context());
}
dt_scheduler::~dt_scheduler()
{
OTDestroyTimerTask(m_lTask);
m_lTask = 0UL;
DisposeOTProcessUPP(m_uppTask);
m_uppTask = NULL;
}
void dt_scheduler::start_polling()
{
m_bReschedule = true;
schedule_task();
}
void dt_scheduler::stop_polling()
{
m_bReschedule = false;
}
void dt_scheduler::schedule_task()
{
if(m_bReschedule)
{
OTScheduleTimerTask(m_lTask, k_ulTimerTaskDelay);
}
}
/*static*/ pascal void dt_scheduler::task_entry(void *pRefCon)
{
dt_scheduler *pThis = reinterpret_cast<dt_scheduler *>(pRefCon);
assert(pThis != NULL);
pThis->task();
}
void dt_scheduler::task()
{
periodic_function();
schedule_task();
}
} // namespace detail
} // namespace mac
} // namespace threads
} // namespace boost

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// Copyright (C) 2001
// Mac Murrett
//
// Permission to use, copy, modify, distribute and sell this software
// and its documentation for any purpose is hereby granted without fee,
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. Mac Murrett makes no representations
// about the suitability of this software for any purpose. It is
// provided "as is" without express or implied warranty.
//
// See http://www.boost.org for most recent version including documentation.
#ifndef BOOST_DT_SCHEDULER_MJM012402_HPP
#define BOOST_DT_SCHEDULER_MJM012402_HPP
#include "periodical.hpp"
#include <OpenTransport.h>
namespace boost {
namespace threads {
namespace mac {
namespace detail {
// class dt_scheduler calls its pure-virtual periodic_function method periodically at
// deferred task time. This is generally 1kHz under Mac OS 9.
class dt_scheduler
{
public:
dt_scheduler();
virtual ~dt_scheduler();
protected:
void start_polling();
void stop_polling();
private:
virtual void periodic_function() = 0;
private:
void schedule_task();
static pascal void task_entry(void *pRefCon);
void task();
private:
bool m_bReschedule;
OTProcessUPP m_uppTask;
long m_lTask;
};
} // namespace detail
} // namespace mac
} // namespace threads
} // namespace boost
#endif // BOOST_DT_SCHEDULER_MJM012402_HPP

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// Copyright (C) 2001
// Mac Murrett
//
// Permission to use, copy, modify, distribute and sell this software
// and its documentation for any purpose is hereby granted without fee,
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. Mac Murrett makes no representations
// about the suitability of this software for any purpose. It is
// provided "as is" without express or implied warranty.
//
// See http://www.boost.org for most recent version including documentation.
#include <Debugging.h>
#include <Multiprocessing.h>
#include "execution_context.hpp"
#include "init.hpp"
namespace boost {
namespace threads {
namespace mac {
execution_context_t execution_context()
{
// make sure that MP services are available the first time through
static bool bIgnored = detail::thread_init();
// first check if we're an MP task
if(MPTaskIsPreemptive(kInvalidID))
{
return(k_eExecutionContextMPTask);
}
#if TARGET_CARBON
// Carbon has TaskLevel
UInt32 ulLevel = TaskLevel();
if(ulLevel == 0UL)
{
return(k_eExecutionContextSystemTask);
}
if(ulLevel & kInDeferredTaskMask)
{
return(k_eExecutionContextDeferredTask);
}
return(k_eExecutionContextOther);
#else
// this can be implemented using TaskLevel if you don't mind linking against
// DebugLib (and therefore breaking Mac OS 8.6 support), or CurrentExecutionLevel.
# error execution_context unimplimented
#endif
}
} // namespace mac
} // namespace threads
} // namespace boost

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// Copyright (C) 2001
// Mac Murrett
//
// Permission to use, copy, modify, distribute and sell this software
// and its documentation for any purpose is hereby granted without fee,
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. Mac Murrett makes no representations
// about the suitability of this software for any purpose. It is
// provided "as is" without express or implied warranty.
//
// See http://www.boost.org for most recent version including documentation.
#ifndef BOOST_EXECUTION_CONTEXT_MJM012402_HPP
#define BOOST_EXECUTION_CONTEXT_MJM012402_HPP
namespace boost {
namespace threads {
namespace mac {
// utility functions for figuring out what context your code is executing in.
// Bear in mind that at_mp and in_blue are the only functions guarenteed by
// Apple to work. There is simply no way of being sure that you will not get
// false readings about task level at interrupt time in blue.
typedef enum {
k_eExecutionContextSystemTask,
k_eExecutionContextDeferredTask,
k_eExecutionContextMPTask,
k_eExecutionContextOther
} execution_context_t;
execution_context_t execution_context();
inline bool at_st()
{ return(execution_context() == k_eExecutionContextSystemTask); }
inline bool at_mp()
{ return(execution_context() == k_eExecutionContextMPTask); }
inline bool in_blue()
{ return(!at_mp()); }
} // namespace mac
} // namespace threads
} // namespace boost
#endif // BOOST_EXECUTION_CONTEXT_MJM012402_HPP

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// Copyright (C) 2001
// Mac Murrett
//
// Permission to use, copy, modify, distribute and sell this software
// and its documentation for any purpose is hereby granted without fee,
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. Mac Murrett makes no representations
// about the suitability of this software for any purpose. It is
// provided "as is" without express or implied warranty.
//
// See http://www.boost.org for most recent version including documentation.
#include "init.hpp"
#include "remote_call_manager.hpp"
#include <boost/thread/detail/singleton.hpp>
#include <Multiprocessing.h>
namespace boost {
namespace threads {
namespace mac {
namespace detail {
namespace {
// force these to get called by the end of static initialization time.
static bool g_bInitialized = (thread_init() && create_singletons());
}
bool thread_init()
{
static bool bResult = MPLibraryIsLoaded();
return(bResult);
}
bool create_singletons()
{
using ::boost::detail::thread::singleton;
singleton<remote_call_manager>::instance();
return(true);
}
} // namespace detail
} // namespace mac
} // namespace threads
} // namespace boost

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// Copyright (C) 2001
// Mac Murrett
//
// Permission to use, copy, modify, distribute and sell this software
// and its documentation for any purpose is hereby granted without fee,
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. Mac Murrett makes no representations
// about the suitability of this software for any purpose. It is
// provided "as is" without express or implied warranty.
//
// See http://www.boost.org for most recent version including documentation.
#ifndef BOOST_INIT_MJM012402_HPP
#define BOOST_INIT_MJM012402_HPP
namespace boost {
namespace threads {
namespace mac {
namespace detail {
bool thread_init();
bool create_singletons();
} // namespace detail
} // namespace mac
} // namespace threads
} // namespace boost
#endif // BOOST_INIT_MJM012402_HPP

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// Copyright (C) 2001
// Mac Murrett
//
// Permission to use, copy, modify, distribute and sell this software
// and its documentation for any purpose is hereby granted without fee,
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. Mac Murrett makes no representations
// about the suitability of this software for any purpose. It is
// provided "as is" without express or implied warranty.
//
// See http://www.boost.org for most recent version including documentation.
#include <cassert>
#include <cstdio>
#include <MacTypes.h>
#include "remote_calls.hpp"
// this function will be called when an assertion fails. We redirect the assertion
// to DebugStr (MacsBug under Mac OS 1.x-9.x, Console under Mac OS X).
void __assertion_failed(char const *pszAssertion, char const *pszFile, int nLine)
{
using std::snprintf;
unsigned char strlDebug[sizeof(Str255) + 1];
char *pszDebug = reinterpret_cast<char *>(&strlDebug[1]);
strlDebug[0] = snprintf(pszDebug, sizeof(Str255), "assertion failed: \"%s\", %s, line %d", pszAssertion, pszFile, nLine);
boost::threads::mac::dt_remote_call(DebugStr, static_cast<ConstStringPtr>(strlDebug));
}

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// Copyright (C) 2001
// Mac Murrett
//
// Permission to use, copy, modify, distribute and sell this software
// and its documentation for any purpose is hereby granted without fee,
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. Mac Murrett makes no representations
// about the suitability of this software for any purpose. It is
// provided "as is" without express or implied warranty.
//
// See http://www.boost.org for most recent version including documentation.
//
// includes
//
#include <abort_exit.h>
#include <console.h>
#include <console_io.h>
#include <misc_io.h>
#include <SIOUX.h>
#include "remote_calls.hpp"
//
// using declarations
//
using std::__file_handle;
using std::__idle_proc;
using std::__io_error;
using std::__no_io_error;
using std::size_t;
using boost::threads::mac::st_remote_call;
//
// prototypes
//
static bool check_console();
static int do_read_console(__file_handle ulHandle, unsigned char *pBuffer, size_t *pCount, __idle_proc pfnIdleProc);
static int do_write_console(__file_handle ulHandle, unsigned char *pBuffer, size_t *pCount, __idle_proc pfnIdleProc);
//
// MSL function replacements
//
// these two functions are called by cin and cout, respectively, as well as by (all?)
// other functions in MSL that do console I/O. All that they do is as the remote
// call manager to ensure that their guts are called at system task time.
int __read_console(__file_handle handle, unsigned char * buffer, size_t * count, __idle_proc idle_proc)
{
return(st_remote_call(do_read_console, handle, buffer, count, idle_proc));
}
int __write_console(__file_handle handle, unsigned char * buffer, size_t * count, __idle_proc idle_proc)
{
return(st_remote_call(do_write_console, handle, buffer, count, idle_proc));
}
//
// implementations
//
static bool check_console()
{
static bool s_bHaveConsole(false);
static bool s_bWontHaveConsole(false);
if(s_bHaveConsole)
{
return(true);
}
if(s_bWontHaveConsole == false)
{
__stdio_atexit();
if(InstallConsole(0) != 0)
{
s_bWontHaveConsole = true;
return(false);
}
__console_exit = RemoveConsole;
s_bHaveConsole = true;
return(true);
}
return(false);
}
int do_read_console(__file_handle /*ulHandle*/, unsigned char *pBuffer, size_t *pCount, __idle_proc /*pfnIdleProc*/)
{
assert(pCount != NULL);
assert(pBuffer != NULL || *pCount == 0UL);
if(check_console() == false)
{
return(__io_error);
}
std::fflush(stdout);
long lCount = ReadCharsFromConsole(reinterpret_cast<char *>(pBuffer), static_cast<long>(*pCount));
*pCount = static_cast<size_t>(lCount);
if(lCount == -1L)
{
return(__io_error);
}
return(__no_io_error);
}
int do_write_console(__file_handle /*ulHandle*/, unsigned char *pBuffer, size_t *pCount, __idle_proc /*pfnIdleProc*/)
{
if(check_console() == false)
{
return(__io_error);
}
long lCount = WriteCharsToConsole(reinterpret_cast<char *>(pBuffer), static_cast<long>(*pCount));
*pCount = static_cast<size_t>(lCount);
if(lCount == -1L)
{
return(__io_error);
}
return(__no_io_error);
}

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// Copyright (C) 2001
// Mac Murrett
//
// Permission to use, copy, modify, distribute and sell this software
// and its documentation for any purpose is hereby granted without fee,
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. Mac Murrett makes no representations
// about the suitability of this software for any purpose. It is
// provided "as is" without express or implied warranty.
//
// See http://www.boost.org for most recent version including documentation.
//
// includes
//
#include <cstdlib>
#include <Multiprocessing.h>
//
// using declarations
//
using std::size_t;
extern "C" {
//
// prototypes
//
void *malloc(size_t ulSize);
void free(void *pBlock);
}
//
// MSL function replacements
//
// all allocation/deallocation currently goes through MPAllocateAligned/MPFree. This
// solution is sub-optimal at best, but will have to do for now.
void *malloc(size_t ulSize)
{
static bool bIgnored = MPLibraryIsLoaded();
return(MPAllocateAligned(ulSize, kMPAllocateDefaultAligned, 0UL));
}
void free(void *pBlock)
{
if(pBlock == NULL) return;
MPFree(pBlock);
}

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// Copyright (C) 2001
// Mac Murrett
//
// Permission to use, copy, modify, distribute and sell this software
// and its documentation for any purpose is hereby granted without fee,
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. Mac Murrett makes no representations
// about the suitability of this software for any purpose. It is
// provided "as is" without express or implied warranty.
//
// See http://www.boost.org for most recent version including documentation.
//
// includes
//
#include <new>
#include <Multiprocessing.h>
//
// using declarations
//
using std::size_t;
using std::bad_alloc;
using std::nothrow_t;
using std::nothrow;
//
// local utility functions
//
// all allocation/deallocation currently goes through MPAllocateAligned/MPFree. This
// solution is sub-optimal at best, but will have to do for now.
inline static void *allocate(size_t ulSize, const nothrow_t &)
{
static bool bIgnored = MPLibraryIsLoaded();
return(MPAllocateAligned(ulSize, kMPAllocateDefaultAligned, 0UL));
}
inline static void *allocate(size_t ulSize)
{
void *pBlock = allocate(ulSize, nothrow);
if(pBlock == NULL)
throw(bad_alloc());
return(pBlock);
}
inline static void deallocate(void *pBlock)
{
if(pBlock == NULL) return;
MPFree(pBlock);
}
//
// global operators
//
void *operator new(size_t ulSize)
{
return(allocate(ulSize));
}
void *operator new[](size_t ulSize)
{
return(allocate(ulSize));
}
void *operator new(size_t ulSize, const nothrow_t &rNoThrow)
{
return(allocate(ulSize, rNoThrow));
}
void *operator new[](size_t ulSize, const nothrow_t &rNoThrow)
{
return(allocate(ulSize, rNoThrow));
}
void operator delete(void *pBlock)
{
deallocate(pBlock);
}
void operator delete[](void *pBlock)
{
deallocate(pBlock);
}
void operator delete(void *pBlock, const nothrow_t &)
{
deallocate(pBlock);
}
void operator delete[](void *pBlock, const nothrow_t &)
{
deallocate(pBlock);
}

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// Copyright (C) 2001
// Mac Murrett
//
// Permission to use, copy, modify, distribute and sell this software
// and its documentation for any purpose is hereby granted without fee,
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. Mac Murrett makes no representations
// about the suitability of this software for any purpose. It is
// provided "as is" without express or implied warranty.
//
// See http://www.boost.org for most recent version including documentation.
#include <cassert>
// we include timesize.mac.h to get whether or not __TIMESIZE_DOUBLE__ is
// defined. This is not safe, given that __TIMESIZE_DOUBLE__ affects MSL
// at MSL's compile time, not ours, so be forgiving if you have changed it
// since you have built MSL.
#include <timesize.mac.h>
#include <time.h>
#include <boost/thread/detail/force_cast.hpp>
#include <boost/thread/xtime.hpp>
#include "execution_context.hpp"
#include <DriverServices.h>
extern "C"
{
clock_t __get_clock();
time_t __get_time();
int __to_gm_time(time_t *pTime);
int __is_dst();
}
static inline uint64_t get_nanoseconds()
{
using boost::detail::thread::force_cast;
return(force_cast<uint64_t>(AbsoluteToNanoseconds(UpTime())));
}
#ifdef __TIMESIZE_DOUBLE__
// return number of microseconds since startup as a double
clock_t __get_clock()
{
static const double k_dNanosecondsPerMicrosecond(1000.0);
return(get_nanoseconds() / k_dNanosecondsPerMicrosecond);
}
#else
// return number of ticks (60th of a second) since startup as a long
clock_t __get_clock()
{
static const uint64_t k_ullTicksPerSecond(60ULL);
static const uint64_t k_ullNanosecondsPerSecond(1000ULL * 1000ULL * 1000ULL);
static const uint64_t k_ullNanosecondsPerTick(k_ullNanosecondsPerSecond / k_ullTicksPerSecond);
return(get_nanoseconds() / k_ullNanosecondsPerTick);
}
#endif
// return number of seconds elapsed since Jan 1, 1970
time_t __get_time()
{
boost::xtime sTime;
int nType = boost::xtime_get(&sTime, boost::TIME_UTC);
assert(nType == boost::TIME_UTC);
return(static_cast<time_t>(sTime.sec));
}
static inline MachineLocation &read_location()
{
static MachineLocation s_sLocation;
assert(boost::threads::mac::at_st());
ReadLocation(&s_sLocation);
return(s_sLocation);
}
static inline MachineLocation &get_location()
{
static MachineLocation &s_rLocation(read_location());
return(s_rLocation);
}
// force the machine location to be cached at static initlialization
static MachineLocation &g_rIgnored(get_location());
static inline long calculate_delta()
{
MachineLocation &rLocation(get_location());
// gmtDelta is a 24-bit, signed integer. We need to strip out the lower 24 bits,
// then sign-extend what we have.
long lDelta = rLocation.u.gmtDelta & 0x00ffffffL;
if((lDelta & 0x00800000L) != 0L)
{
lDelta |= 0xFF000000;
}
return(lDelta);
}
static inline bool check_if_location_is_broken()
{
MachineLocation &rLocation(get_location());
if(rLocation.latitude == 0 && rLocation.longitude == 0 && rLocation.u.gmtDelta == 0)
return(true);
return(false);
}
static inline bool location_is_broken()
{
static bool s_bLocationIsBroken(check_if_location_is_broken());
return(s_bLocationIsBroken);
}
// translate time to GMT
int __to_gm_time(time_t *pTime)
{
if(location_is_broken())
{
return(0);
}
static long s_lDelta(calculate_delta());
*pTime -= s_lDelta;
return(1);
}
static inline bool is_daylight_savings_time()
{
MachineLocation &rLocation(get_location());
return(rLocation.u.dlsDelta != 0);
}
// check if we're in daylight savings time
int __is_dst()
{
if(location_is_broken())
{
return(-1);
}
static bool bIsDaylightSavingsTime(is_daylight_savings_time());
return(static_cast<int>(bIsDaylightSavingsTime));
}

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// Copyright (C) 2001
// Mac Murrett
//
// Permission to use, copy, modify, distribute and sell this software
// and its documentation for any purpose is hereby granted without fee,
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. Mac Murrett makes no representations
// about the suitability of this software for any purpose. It is
// provided "as is" without express or implied warranty.
//
// See http://www.boost.org for most recent version including documentation.
#include "os.hpp"
#include <cassert>
#include <Gestalt.h>
namespace boost {
namespace threads {
namespace mac {
namespace os {
// read the OS version from Gestalt
static inline long get_version()
{
long lVersion;
OSErr nErr = Gestalt(gestaltSystemVersion, &lVersion);
assert(nErr == noErr);
return(lVersion);
}
// check if we're running under Mac OS X and cache that information
bool x()
{
static bool bX = (version() >= 0x1000);
return(bX);
}
// read the OS version and cache it
long version()
{
static long lVersion = get_version();
return(lVersion);
}
} // namespace os
} // namespace mac
} // namespace threads
} // namespace boost

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// Copyright (C) 2001
// Mac Murrett
//
// Permission to use, copy, modify, distribute and sell this software
// and its documentation for any purpose is hereby granted without fee,
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. Mac Murrett makes no representations
// about the suitability of this software for any purpose. It is
// provided "as is" without express or implied warranty.
//
// See http://www.boost.org for most recent version including documentation.
#ifndef BOOST_OS_MJM012402_HPP
#define BOOST_OS_MJM012402_HPP
namespace boost {
namespace threads {
namespace mac {
namespace os {
// functions to determine the OS environment. With namespaces, you get a cute call:
// mac::os::x
bool x();
long version();
} // namespace os
} // namespace mac
} // namespace threads
} // namespace boost
#endif // BOOST_OS_MJM012402_HPP

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// Copyright (C) 2001
// Mac Murrett
//
// Permission to use, copy, modify, distribute and sell this software
// and its documentation for any purpose is hereby granted without fee,
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. Mac Murrett makes no representations
// about the suitability of this software for any purpose. It is
// provided "as is" without express or implied warranty.
//
// See http://www.boost.org for most recent version including documentation.
#include "ot_context.hpp"
#include "execution_context.hpp"
#include <cassert>
namespace boost {
namespace threads {
namespace mac {
namespace detail {
ot_context::ot_context()
{
assert(at_st());
OSStatus lStatus = InitOpenTransportInContext(0UL, &m_pContext);
// TODO - throw on error
assert(lStatus == noErr);
}
ot_context::~ot_context()
{
CloseOpenTransportInContext(m_pContext);
}
} // namespace detail
} // namespace mac
} // namespace threads
} // namespace boost

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// Copyright (C) 2001
// Mac Murrett
//
// Permission to use, copy, modify, distribute and sell this software
// and its documentation for any purpose is hereby granted without fee,
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. Mac Murrett makes no representations
// about the suitability of this software for any purpose. It is
// provided "as is" without express or implied warranty.
//
// See http://www.boost.org for most recent version including documentation.
#ifndef BOOST_OT_CONTEXT_MJM012402_HPP
#define BOOST_OT_CONTEXT_MJM012402_HPP
#include <OpenTransport.h>
#include <boost/utility.hpp>
namespace boost {
namespace threads {
namespace mac {
namespace detail {
// class ot_context is intended to be used only as a singleton. All that this class
// does is ask OpenTransport to create him an OTClientContextPtr, and then doles
// this out to anyone who wants it. ot_context should only be instantiated at
// system task time.
class ot_context: private noncopyable
{
protected:
ot_context();
~ot_context();
public:
OTClientContextPtr get_context();
private:
OTClientContextPtr m_pContext;
};
inline OTClientContextPtr ot_context::get_context()
{ return(m_pContext); }
} // namespace detail
} // namespace mac
} // namespace threads
} // namespace boost
#endif // BOOST_OT_CONTEXT_MJM012402_HPP

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// Copyright (C) 2001
// Mac Murrett
//
// Permission to use, copy, modify, distribute and sell this software
// and its documentation for any purpose is hereby granted without fee,
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. Mac Murrett makes no representations
// about the suitability of this software for any purpose. It is
// provided "as is" without express or implied warranty.
//
// See http://www.boost.org for most recent version including documentation.
#ifndef BOOST_PACKAGE_MJM012402_HPP
#define BOOST_PACKAGE_MJM012402_HPP
namespace boost {
namespace threads {
namespace mac {
namespace detail {
class base_package: private noncopyable
{
public:
virtual void accept() = 0;
};
template<class R>
class package: public base_package
{
public:
inline package(function<R> &rFunctor):
m_rFunctor(rFunctor)
{ /* no-op */ }
inline ~package()
{ /* no-op */ }
virtual void accept()
{ m_oR = m_rFunctor(); }
inline R return_value()
{ return(m_oR); }
private:
function<R> &m_rFunctor;
R m_oR;
};
template<>
class package<void>: public base_package
{
public:
inline package(function<void> &rFunctor):
m_rFunctor(rFunctor)
{ /* no-op */ }
inline ~package()
{ /* no-op */ }
virtual void accept()
{ m_rFunctor(); }
inline void return_value()
{ return; }
private:
function<void> &m_rFunctor;
};
} // namespace detail
} // namespace mac
} // namespace threads
} // namespace boost
#endif // BOOST_PACKAGE_MJM012402_HPP

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// Copyright (C) 2001
// Mac Murrett
//
// Permission to use, copy, modify, distribute and sell this software
// and its documentation for any purpose is hereby granted without fee,
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. Mac Murrett makes no representations
// about the suitability of this software for any purpose. It is
// provided "as is" without express or implied warranty.
//
// See http://www.boost.org for most recent version including documentation.
#ifndef BOOST_PERIODICAL_MJM012402_HPP
#define BOOST_PERIODICAL_MJM012402_HPP
#include <boost/function.hpp>
#include <boost/utility.hpp>
namespace boost {
namespace threads {
namespace mac {
namespace detail {
// class periodical inherits from its template parameter, which should follow the
// pattern set by classes dt_scheduler and st_scheduler. periodical knows how to
// call a boost::function, where the xx_scheduler classes only know to to call a
// member periodically.
template<class Scheduler>
class periodical: private noncopyable, private Scheduler
{
public:
periodical(function<void> &rFunction);
~periodical();
public:
void start();
void stop();
protected:
virtual void periodic_function();
private:
function<void> m_oFunction;
};
template<class Scheduler>
periodical<Scheduler>::periodical(function<void> &rFunction):
m_oFunction(rFunction)
{
// no-op
}
template<class Scheduler>
periodical<Scheduler>::~periodical()
{
stop();
}
template<class Scheduler>
void periodical<Scheduler>::start()
{
start_polling();
}
template<class Scheduler>
void periodical<Scheduler>::stop()
{
stop_polling();
}
template<class Scheduler>
inline void periodical<Scheduler>::periodic_function()
{
try
{
m_oFunction();
}
catch(...)
{
}
}
} // namespace detail
} // namespace mac
} // namespace threads
} // namespace boost
#endif // BOOST_PERIODICAL_MJM012402_HPP

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// Copyright (C) 2001
// Mac Murrett
//
// Permission to use, copy, modify, distribute and sell this software
// and its documentation for any purpose is hereby granted without fee,
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. Mac Murrett makes no representations
// about the suitability of this software for any purpose. It is
// provided "as is" without express or implied warranty.
//
// See http://www.boost.org for most recent version including documentation.
#define NDEBUG
#define TARGET_CARBON 1

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// Copyright (C) 2001
// Mac Murrett
//
// Permission to use, copy, modify, distribute and sell this software
// and its documentation for any purpose is hereby granted without fee,
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. Mac Murrett makes no representations
// about the suitability of this software for any purpose. It is
// provided "as is" without express or implied warranty.
//
// See http://www.boost.org for most recent version including documentation.
#include "remote_call_manager.hpp"
#include <boost/bind.hpp>
namespace boost {
namespace threads {
namespace mac {
namespace detail {
using detail::delivery_man;
remote_call_manager::remote_call_manager():
m_oDTDeliveryMan(),
m_oSTDeliveryMan(),
m_oDTFunction(bind(&delivery_man::accept_deliveries, &m_oDTDeliveryMan)),
m_oSTFunction(bind(&delivery_man::accept_deliveries, &m_oSTDeliveryMan)),
m_oDTPeriodical(m_oDTFunction),
m_oSTPeriodical(m_oSTFunction)
{
m_oDTPeriodical.start();
m_oSTPeriodical.start();
}
remote_call_manager::~remote_call_manager()
{
}
} // namespace detail
} // namespace mac
} // namespace threads
} // namespace boost

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// Copyright (C) 2001
// Mac Murrett
//
// Permission to use, copy, modify, distribute and sell this software
// and its documentation for any purpose is hereby granted without fee,
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. Mac Murrett makes no representations
// about the suitability of this software for any purpose. It is
// provided "as is" without express or implied warranty.
//
// See http://www.boost.org for most recent version including documentation.
#ifndef BOOST_REMOTE_CALL_MANAGER_MJM012402_HPP
#define BOOST_REMOTE_CALL_MANAGER_MJM012402_HPP
#include <boost/utility.hpp>
#include "delivery_man.hpp"
#include "dt_scheduler.hpp"
#include "periodical.hpp"
#include "execution_context.hpp"
#include "st_scheduler.hpp"
namespace boost {
namespace threads {
namespace mac {
namespace detail {
// class remote_call_manager is used by the remote call functions (dt_remote_call and
// st_remote_call) to execute functions in non-MP contexts.
class remote_call_manager: private noncopyable
{
protected:
remote_call_manager();
~remote_call_manager();
public:
template<class R>
R execute_at_dt(function<R> &rFunctor);
template<class R>
R execute_at_st(function<R> &rFunctor);
private:
template<class R>
static R execute_now(function<R> &rFunctor);
private:
delivery_man m_oDTDeliveryMan;
delivery_man m_oSTDeliveryMan;
function<void> m_oDTFunction;
function<void> m_oSTFunction;
periodical<dt_scheduler> m_oDTPeriodical;
periodical<st_scheduler> m_oSTPeriodical;
};
template<class R>
/*static*/ inline R remote_call_manager::execute_now(function<R> &rFunctor)
{
return(rFunctor());
}
template<>
/*static*/ inline void remote_call_manager::execute_now<void>(function<void> &rFunctor)
{
rFunctor();
}
template<class R>
inline R remote_call_manager::execute_at_dt(function<R> &rFunctor)
{
if(at_mp())
{
return(m_oDTDeliveryMan.deliver(rFunctor));
}
return(execute_now(rFunctor));
}
template<class R>
inline R remote_call_manager::execute_at_st(function<R> &rFunctor)
{
if(at_mp())
{
return(m_oSTDeliveryMan.deliver(rFunctor));
}
assert(at_st());
return(execute_now(rFunctor));
}
} // namespace detail
} // namespace mac
} // namespace threads
} // namespace boost
#endif // BOOST_REMOTE_CALL_MANAGER_MJM012402_HPP

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// Copyright (C) 2001
// Mac Murrett
//
// Permission to use, copy, modify, distribute and sell this software
// and its documentation for any purpose is hereby granted without fee,
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. Mac Murrett makes no representations
// about the suitability of this software for any purpose. It is
// provided "as is" without express or implied warranty.
//
// See http://www.boost.org for most recent version including documentation.
#ifndef BOOST_REMOTE_CALLS_MJM012402_HPP
#define BOOST_REMOTE_CALLS_MJM012402_HPP
#include <boost/bind.hpp>
#include "remote_call_manager.hpp"
#include <boost/thread/detail/singleton.hpp>
// this file contains macros to generate functions with the signatures:
// ReturnType st_remote_call([pascal] ReturnType (*pfnFunction)(
// [Argument1Type[, Argument2Type[...]]])
// [, Argument1Type oArgument1[, Argument2Type oArgument2[...]]])
// and
// ReturnType dt_remote_call([pascal] ReturnType (*pfnFunction)(
// [Argument1Type[, Argument2Type[...]]])
// [, Argument1Type oArgument1[, Argument2Type oArgument2[...]]])
// in other words, identical to the function pointer versions of boost::bind, but
// with the return type returned. The purpose of these functions is to be able to
// request that a function be called at system task time or deferred task time, then
// sleep until it is called, and finally get back its return value.
#define BOOST_REMOTE_CALL_CLASS_LIST_0
#define BOOST_REMOTE_CALL_CLASS_LIST_1 BOOST_REMOTE_CALL_CLASS_LIST_0, class A1
#define BOOST_REMOTE_CALL_CLASS_LIST_2 BOOST_REMOTE_CALL_CLASS_LIST_1, class A2
#define BOOST_REMOTE_CALL_CLASS_LIST_3 BOOST_REMOTE_CALL_CLASS_LIST_2, class A3
#define BOOST_REMOTE_CALL_CLASS_LIST_4 BOOST_REMOTE_CALL_CLASS_LIST_3, class A4
#define BOOST_REMOTE_CALL_CLASS_LIST_5 BOOST_REMOTE_CALL_CLASS_LIST_4, class A5
#define BOOST_REMOTE_CALL_CLASS_LIST_6 BOOST_REMOTE_CALL_CLASS_LIST_5, class A6
#define BOOST_REMOTE_CALL_CLASS_LIST_7 BOOST_REMOTE_CALL_CLASS_LIST_6, class A7
#define BOOST_REMOTE_CALL_CLASS_LIST_8 BOOST_REMOTE_CALL_CLASS_LIST_7, class A8
#define BOOST_REMOTE_CALL_CLASS_LIST_9 BOOST_REMOTE_CALL_CLASS_LIST_8, class A9
#define BOOST_REMOTE_CALL_ARGUMENT_LIST_0
#define BOOST_REMOTE_CALL_ARGUMENT_LIST_1 BOOST_REMOTE_CALL_ARGUMENT_LIST_0 A1 oA1
#define BOOST_REMOTE_CALL_ARGUMENT_LIST_2 BOOST_REMOTE_CALL_ARGUMENT_LIST_1, A2 oA2
#define BOOST_REMOTE_CALL_ARGUMENT_LIST_3 BOOST_REMOTE_CALL_ARGUMENT_LIST_2, A3 oA3
#define BOOST_REMOTE_CALL_ARGUMENT_LIST_4 BOOST_REMOTE_CALL_ARGUMENT_LIST_3, A4 oA4
#define BOOST_REMOTE_CALL_ARGUMENT_LIST_5 BOOST_REMOTE_CALL_ARGUMENT_LIST_4, A5 oA5
#define BOOST_REMOTE_CALL_ARGUMENT_LIST_6 BOOST_REMOTE_CALL_ARGUMENT_LIST_5, A6 oA6
#define BOOST_REMOTE_CALL_ARGUMENT_LIST_7 BOOST_REMOTE_CALL_ARGUMENT_LIST_6, A7 oA7
#define BOOST_REMOTE_CALL_ARGUMENT_LIST_8 BOOST_REMOTE_CALL_ARGUMENT_LIST_7, A8 oA8
#define BOOST_REMOTE_CALL_ARGUMENT_LIST_9 BOOST_REMOTE_CALL_ARGUMENT_LIST_8, A9 oA9
#define BOOST_REMOTE_CALL_FUNCTION_ARGUMENT_LIST_0
#define BOOST_REMOTE_CALL_FUNCTION_ARGUMENT_LIST_1 BOOST_REMOTE_CALL_FUNCTION_ARGUMENT_LIST_0, oA1
#define BOOST_REMOTE_CALL_FUNCTION_ARGUMENT_LIST_2 BOOST_REMOTE_CALL_FUNCTION_ARGUMENT_LIST_1, oA2
#define BOOST_REMOTE_CALL_FUNCTION_ARGUMENT_LIST_3 BOOST_REMOTE_CALL_FUNCTION_ARGUMENT_LIST_2, oA3
#define BOOST_REMOTE_CALL_FUNCTION_ARGUMENT_LIST_4 BOOST_REMOTE_CALL_FUNCTION_ARGUMENT_LIST_3, oA4
#define BOOST_REMOTE_CALL_FUNCTION_ARGUMENT_LIST_5 BOOST_REMOTE_CALL_FUNCTION_ARGUMENT_LIST_4, oA5
#define BOOST_REMOTE_CALL_FUNCTION_ARGUMENT_LIST_6 BOOST_REMOTE_CALL_FUNCTION_ARGUMENT_LIST_5, oA6
#define BOOST_REMOTE_CALL_FUNCTION_ARGUMENT_LIST_7 BOOST_REMOTE_CALL_FUNCTION_ARGUMENT_LIST_6, oA7
#define BOOST_REMOTE_CALL_FUNCTION_ARGUMENT_LIST_8 BOOST_REMOTE_CALL_FUNCTION_ARGUMENT_LIST_7, oA8
#define BOOST_REMOTE_CALL_FUNCTION_ARGUMENT_LIST_9 BOOST_REMOTE_CALL_FUNCTION_ARGUMENT_LIST_8, oA9
#define BOOST_REMOTE_CALL_COMMA_0
#define BOOST_REMOTE_CALL_COMMA_1 ,
#define BOOST_REMOTE_CALL_COMMA_2 ,
#define BOOST_REMOTE_CALL_COMMA_3 ,
#define BOOST_REMOTE_CALL_COMMA_4 ,
#define BOOST_REMOTE_CALL_COMMA_5 ,
#define BOOST_REMOTE_CALL_COMMA_6 ,
#define BOOST_REMOTE_CALL_COMMA_7 ,
#define BOOST_REMOTE_CALL_COMMA_8 ,
#define BOOST_REMOTE_CALL_COMMA_9 ,
// this is the macro that ties it all together. From here, we generate all forms of
// dt_remote_call and st_remote_call.
#define BOOST_REMOTE_CALL(context, stack, n) \
template<class R BOOST_REMOTE_CALL_CLASS_LIST_ ## n> \
inline R context ## _remote_call(stack R (*pfnF)( \
BOOST_REMOTE_CALL_ARGUMENT_LIST_ ## n) \
BOOST_REMOTE_CALL_COMMA_ ## n \
BOOST_REMOTE_CALL_ARGUMENT_LIST_ ## n) \
{ \
using ::boost::detail::thread::singleton; \
using detail::remote_call_manager; \
function<R> oFunc(bind(pfnF BOOST_REMOTE_CALL_FUNCTION_ARGUMENT_LIST_ ## n)); \
remote_call_manager &rManager(singleton<remote_call_manager>::instance()); \
return(rManager.execute_at_ ## context(oFunc)); \
}
namespace boost {
namespace threads {
namespace mac {
BOOST_REMOTE_CALL(st, , 0)
BOOST_REMOTE_CALL(st, , 1)
BOOST_REMOTE_CALL(st, , 2)
BOOST_REMOTE_CALL(st, , 3)
BOOST_REMOTE_CALL(st, , 4)
BOOST_REMOTE_CALL(st, , 5)
BOOST_REMOTE_CALL(st, , 6)
BOOST_REMOTE_CALL(st, , 7)
BOOST_REMOTE_CALL(st, , 8)
BOOST_REMOTE_CALL(st, , 9)
BOOST_REMOTE_CALL(dt, , 0)
BOOST_REMOTE_CALL(dt, , 1)
BOOST_REMOTE_CALL(dt, , 2)
BOOST_REMOTE_CALL(dt, , 3)
BOOST_REMOTE_CALL(dt, , 4)
BOOST_REMOTE_CALL(dt, , 5)
BOOST_REMOTE_CALL(dt, , 6)
BOOST_REMOTE_CALL(dt, , 7)
BOOST_REMOTE_CALL(dt, , 8)
BOOST_REMOTE_CALL(dt, , 9)
BOOST_REMOTE_CALL(st, pascal, 0)
BOOST_REMOTE_CALL(st, pascal, 1)
BOOST_REMOTE_CALL(st, pascal, 2)
BOOST_REMOTE_CALL(st, pascal, 3)
BOOST_REMOTE_CALL(st, pascal, 4)
BOOST_REMOTE_CALL(st, pascal, 5)
BOOST_REMOTE_CALL(st, pascal, 6)
BOOST_REMOTE_CALL(st, pascal, 7)
BOOST_REMOTE_CALL(st, pascal, 8)
BOOST_REMOTE_CALL(st, pascal, 9)
BOOST_REMOTE_CALL(dt, pascal, 0)
BOOST_REMOTE_CALL(dt, pascal, 1)
BOOST_REMOTE_CALL(dt, pascal, 2)
BOOST_REMOTE_CALL(dt, pascal, 3)
BOOST_REMOTE_CALL(dt, pascal, 4)
BOOST_REMOTE_CALL(dt, pascal, 5)
BOOST_REMOTE_CALL(dt, pascal, 6)
BOOST_REMOTE_CALL(dt, pascal, 7)
BOOST_REMOTE_CALL(dt, pascal, 8)
BOOST_REMOTE_CALL(dt, pascal, 9)
} // namespace mac
} // namespace threads
} // namespace boost
#endif // BOOST_REMOTE_CALLS_MJM012402_HPP

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// Copyright (C) 2001
// Mac Murrett
//
// Permission to use, copy, modify, distribute and sell this software
// and its documentation for any purpose is hereby granted without fee,
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. Mac Murrett makes no representations
// about the suitability of this software for any purpose. It is
// provided "as is" without express or implied warranty.
//
// See http://www.boost.org for most recent version including documentation.
#include <DriverServices.h>
#include <Events.h>
#include <Multiprocessing.h>
#include <Threads.h>
#include <boost/bind.hpp>
#include <boost/function.hpp>
#include <boost/thread/detail/force_cast.hpp>
#include <limits>
#include "execution_context.hpp"
using boost::detail::thread::force_cast;
namespace boost {
namespace threads {
namespace mac {
namespace detail {
static OSStatus safe_wait(function<OSStatus, Duration> &rFunction, Duration lDuration);
// we call WNE to allow tasks that own the resource the blue is waiting on system
// task time, in case they are blocked on an ST remote call (or a memory allocation
// for that matter).
static void idle()
{
if(at_st())
{
EventRecord sEvent;
bool bEvent = WaitNextEvent(0U, &sEvent, 0UL, NULL);
}
}
OSStatus safe_wait_on_semaphore(MPSemaphoreID pSemaphoreID, Duration lDuration)
{
function<OSStatus, Duration> oWaitOnSemaphore;
oWaitOnSemaphore = bind(MPWaitOnSemaphore, pSemaphoreID, _1);
return(safe_wait(oWaitOnSemaphore, lDuration));
}
OSStatus safe_enter_critical_region(MPCriticalRegionID pCriticalRegionID, Duration lDuration, MPCriticalRegionID pCriticalRegionCriticalRegionID/* = kInvalidID*/)
{
if(pCriticalRegionCriticalRegionID != kInvalidID)
{
if(at_mp())
{
// enter the critical region's critical region
OSStatus lStatus = noErr;
AbsoluteTime sExpiration;
if(lDuration != kDurationImmediate && lDuration != kDurationForever)
{
sExpiration = AddDurationToAbsolute(lDuration, UpTime());
}
lStatus = MPEnterCriticalRegion(pCriticalRegionCriticalRegionID, lDuration);
assert(lStatus == noErr || lStatus == kMPTimeoutErr);
if(lStatus == noErr)
{
// calculate a new duration
if(lDuration != kDurationImmediate && lDuration != kDurationForever)
{
// check if we have any time left
AbsoluteTime sUpTime(UpTime());
if(force_cast<uint64_t>(sExpiration) > force_cast<uint64_t>(sUpTime))
{
// reset our duration to our remaining time
lDuration = AbsoluteDeltaToDuration(sExpiration, sUpTime);
}
else
{
// no time left
lDuration = kDurationImmediate;
}
}
// if we entered the critical region, exit it again
lStatus = MPExitCriticalRegion(pCriticalRegionCriticalRegionID);
assert(lStatus == noErr);
}
else
{
// otherwise, give up
return(lStatus);
}
}
else
{
// if we're at system task time, try to enter the critical region's critical
// region until we succeed. MP tasks will block on this until we let it go.
OSStatus lStatus;
do
{
lStatus = MPEnterCriticalRegion(pCriticalRegionCriticalRegionID, kDurationImmediate);
} while(lStatus == kMPTimeoutErr);
assert(lStatus == noErr);
}
}
// try to enter the critical region
function<OSStatus, Duration> oEnterCriticalRegion;
oEnterCriticalRegion = bind(MPEnterCriticalRegion, pCriticalRegionID, _1);
OSStatus lStatus = safe_wait(oEnterCriticalRegion, lDuration);
// if we entered the critical region's critical region to get the critical region,
// exit the critical region's critical region.
if(pCriticalRegionCriticalRegionID != kInvalidID && at_mp() == false)
{
lStatus = MPExitCriticalRegion(pCriticalRegionCriticalRegionID);
assert(lStatus == noErr);
}
return(lStatus);
}
OSStatus safe_wait_on_queue(MPQueueID pQueueID, void **pParam1, void **pParam2, void **pParam3, Duration lDuration)
{
function<OSStatus, Duration> oWaitOnQueue;
oWaitOnQueue = bind(MPWaitOnQueue, pQueueID, pParam1, pParam2, pParam3, _1);
return(safe_wait(oWaitOnQueue, lDuration));
}
OSStatus safe_delay_until(AbsoluteTime *pWakeUpTime)
{
if(execution_context() == k_eExecutionContextMPTask)
{
return(MPDelayUntil(pWakeUpTime));
}
else
{
uint64_t ullWakeUpTime = force_cast<uint64_t>(*pWakeUpTime);
while(force_cast<uint64_t>(UpTime()) < ullWakeUpTime)
{
idle();
}
return(noErr);
}
}
OSStatus safe_wait(function<OSStatus, Duration> &rFunction, Duration lDuration)
{
if(execution_context() == k_eExecutionContextMPTask)
{
return(rFunction(lDuration));
}
else
{
uint64_t ullExpiration = 0ULL;
// get the expiration time in UpTime units
if(lDuration == kDurationForever)
{
ullExpiration = ::std::numeric_limits<uint64_t>::max();
}
else if(lDuration == kDurationImmediate)
{
ullExpiration = force_cast<uint64_t>(UpTime());
}
else
{
AbsoluteTime sExpiration = AddDurationToAbsolute(lDuration, UpTime());
ullExpiration = force_cast<uint64_t>(sExpiration);
}
OSStatus lStatus;
bool bExpired = false;
do
{
lStatus = rFunction(kDurationImmediate);
// mm - "if" #if 0'd out to allow task time to threads blocked on I/O
#if 0
if(lStatus == kMPTimeoutErr)
#endif
{
idle();
}
if(lDuration != kDurationForever)
{
bExpired = (force_cast<uint64_t>(UpTime()) < ullExpiration);
}
} while(lStatus == kMPTimeoutErr && bExpired == false);
return(lStatus);
}
}
} // namespace detail
} // namespace mac
} // namespace threads
} // namespace boost

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// Copyright (C) 2001
// Mac Murrett
//
// Permission to use, copy, modify, distribute and sell this software
// and its documentation for any purpose is hereby granted without fee,
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. Mac Murrett makes no representations
// about the suitability of this software for any purpose. It is
// provided "as is" without express or implied warranty.
//
// See http://www.boost.org for most recent version including documentation.
#ifndef BOOST_SAFE_MJM012402_HPP
#define BOOST_SAFE_MJM012402_HPP
#include <Multiprocessing.h>
namespace boost {
namespace threads {
namespace mac {
namespace detail {
// these functions are used to wain in an execution context-independent manor. All of these
// functions are both MP- and ST-safe.
OSStatus safe_wait_on_semaphore(MPSemaphoreID pSemaphoreID, Duration lDuration);
OSStatus safe_enter_critical_region(MPCriticalRegionID pCriticalRegionID, Duration lDuration, MPCriticalRegionID pCriticalRegionCriticalRegionID = kInvalidID);
OSStatus safe_wait_on_queue(MPQueueID pQueueID, void **pParam1, void **pParam2, void **pParam3, Duration lDuration);
OSStatus safe_delay_until(AbsoluteTime *pWakeUpTime);
} // namespace detail
} // namespace mac
} // namespace threads
} // namespace boost
#endif // BOOST_SAFE_MJM012402_HPP

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@@ -0,0 +1,53 @@
// Copyright (C) 2001
// Mac Murrett
//
// Permission to use, copy, modify, distribute and sell this software
// and its documentation for any purpose is hereby granted without fee,
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. Mac Murrett makes no representations
// about the suitability of this software for any purpose. It is
// provided "as is" without express or implied warranty.
//
// See http://www.boost.org for most recent version including documentation.
#include "scoped_critical_region.hpp"
#include "init.hpp"
#include <cassert>
namespace boost {
namespace threads {
namespace mac {
namespace detail {
scoped_critical_region::scoped_critical_region():
m_pCriticalRegionID(kInvalidID)
{
static bool bIgnored = thread_init();
OSStatus lStatus = MPCreateCriticalRegion(&m_pCriticalRegionID);
if(lStatus != noErr || m_pCriticalRegionID == kInvalidID)
throw(thread_resource_error());
}
scoped_critical_region::~scoped_critical_region()
{
OSStatus lStatus = MPDeleteCriticalRegion(m_pCriticalRegionID);
assert(lStatus == noErr);
}
} // namespace detail
} // namespace mac
} // namespace threads
} // namespace boost

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@@ -0,0 +1,69 @@
// Copyright (C) 2001
// Mac Murrett
//
// Permission to use, copy, modify, distribute and sell this software
// and its documentation for any purpose is hereby granted without fee,
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. Mac Murrett makes no representations
// about the suitability of this software for any purpose. It is
// provided "as is" without express or implied warranty.
//
// See http://www.boost.org for most recent version including documentation.
#ifndef BOOST_SCOPED_CRITICAL_REGION_MJM012402_HPP
#define BOOST_SCOPED_CRITICAL_REGION_MJM012402_HPP
#include <boost/thread/exceptions.hpp>
#include <Multiprocessing.h>
namespace boost {
namespace threads {
namespace mac {
namespace detail {
// class scoped_critical_region probably needs a new name. Although the current name
// is accurate, it can be read to mean that a critical region is entered for the
// current scope. In reality, a critical region is _created_ for the current scope.
// This class is intended as a replacement for MPCriticalRegionID that will
// automatically create and dispose of itself.
class scoped_critical_region
{
public:
scoped_critical_region();
~scoped_critical_region();
public:
operator const MPCriticalRegionID &() const;
const MPCriticalRegionID &get() const;
private:
MPCriticalRegionID m_pCriticalRegionID;
};
// these are inlined for speed.
inline scoped_critical_region::operator const MPCriticalRegionID &() const
{ return(m_pCriticalRegionID); }
inline const MPCriticalRegionID &scoped_critical_region::get() const
{ return(m_pCriticalRegionID); }
} // namespace detail
} // namespace mac
} // namespace threads
} // namespace boost
#endif // BOOST_SCOPED_CRITICAL_REGION_MJM012402_HPP

91
src/mac/st_scheduler.cpp Normal file
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@@ -0,0 +1,91 @@
// Copyright (C) 2001
// Mac Murrett
//
// Permission to use, copy, modify, distribute and sell this software
// and its documentation for any purpose is hereby granted without fee,
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. Mac Murrett makes no representations
// about the suitability of this software for any purpose. It is
// provided "as is" without express or implied warranty.
//
// See http://www.boost.org for most recent version including documentation.
#include "st_scheduler.hpp"
#include <cassert>
namespace boost {
namespace threads {
namespace mac {
namespace detail {
#if TARGET_CARBON
st_scheduler::st_scheduler():
m_uppTask(NULL),
m_pTimer(NULL)
{
m_uppTask = NewEventLoopTimerUPP(task_entry);
// TODO - throw on error
assert(m_uppTask != NULL);
}
st_scheduler::~st_scheduler()
{
DisposeEventLoopTimerUPP(m_uppTask);
m_uppTask = NULL;
}
void st_scheduler::start_polling()
{
assert(m_pTimer == NULL);
OSStatus lStatus = InstallEventLoopTimer(GetMainEventLoop(),
0 * kEventDurationSecond,
kEventDurationMillisecond,
m_uppTask,
this,
&m_pTimer);
// TODO - throw on error
assert(lStatus == noErr);
}
void st_scheduler::stop_polling()
{
assert(m_pTimer != NULL);
OSStatus lStatus = RemoveEventLoopTimer(m_pTimer);
assert(lStatus == noErr);
m_pTimer = NULL;
}
/*static*/ pascal void st_scheduler::task_entry(EventLoopTimerRef /*pTimer*/, void *pRefCon)
{
st_scheduler *pThis = reinterpret_cast<st_scheduler *>(pRefCon);
assert(pThis != NULL);
pThis->task();
}
void st_scheduler::task()
{
periodic_function();
}
#else
# error st_scheduler unimplemented!
#endif
} // namespace detail
} // namespace mac
} // namespace threads
} // namespace boost

73
src/mac/st_scheduler.hpp Normal file
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@@ -0,0 +1,73 @@
// Copyright (C) 2001
// Mac Murrett
//
// Permission to use, copy, modify, distribute and sell this software
// and its documentation for any purpose is hereby granted without fee,
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. Mac Murrett makes no representations
// about the suitability of this software for any purpose. It is
// provided "as is" without express or implied warranty.
//
// See http://www.boost.org for most recent version including documentation.
#ifndef BOOST_ST_SCHEDULER_MJM012402_HPP
#define BOOST_ST_SCHEDULER_MJM012402_HPP
#include <CarbonEvents.h>
namespace boost {
namespace threads {
namespace mac {
namespace detail {
// class st_scheduler calls its pure-virtual periodic_function method periodically at
// system task time. This is generally 40Hz under Mac OS 9.
class st_scheduler
{
public:
st_scheduler();
virtual ~st_scheduler();
protected:
void start_polling();
void stop_polling();
private:
virtual void periodic_function() = 0;
#if TARGET_CARBON
// use event loop timers under Carbon
private:
static pascal void task_entry(EventLoopTimerRef pTimer, void *pRefCon);
void task();
private:
EventLoopTimerUPP m_uppTask;
EventLoopTimerRef m_pTimer;
#else
// this can be implemented using OT system tasks. This would be mostly a copy-and-
// paste of the dt_scheduler code, replacing DeferredTask with SystemTask and DT
// with ST.
# error st_scheduler unimplemented!
#endif
};
} // namespace detail
} // namespace mac
} // namespace threads
} // namespace boost
#endif // BOOST_ST_SCHEDULER_MJM012402_HPP

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@@ -0,0 +1,62 @@
// Copyright (C) 2001
// Mac Murrett
//
// Permission to use, copy, modify, distribute and sell this software
// and its documentation for any purpose is hereby granted without fee,
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. Mac Murrett makes no representations
// about the suitability of this software for any purpose. It is
// provided "as is" without express or implied warranty.
//
// See http://www.boost.org for most recent version including documentation.
#include "thread_cleanup.hpp"
namespace boost {
namespace threads {
namespace mac {
namespace detail {
namespace {
TaskStorageIndex g_ulIndex(0UL);
} // anonymous namespace
void do_thread_startup()
{
if(g_ulIndex == 0UL)
{
OSStatus lStatus = MPAllocateTaskStorageIndex(&g_ulIndex);
assert(lStatus == noErr);
}
set_thread_cleanup_task(NULL);
}
void do_thread_cleanup()
{
void (*pfnTask)() = MPGetTaskValue(g_ulIndex)
}
void set_thread_cleanup_task(void (*pfnTask)())
{
lStatus = MPSetTaskValue(g_ulIndex, reinterpret_cast<TaskStorageValue>(pfnTask));
assert(lStatus == noErr);
}
} // namespace detail
} // namespace mac
} // namespace threads
} // namespace boost

View File

@@ -0,0 +1,42 @@
// Copyright (C) 2001
// Mac Murrett
//
// Permission to use, copy, modify, distribute and sell this software
// and its documentation for any purpose is hereby granted without fee,
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. Mac Murrett makes no representations
// about the suitability of this software for any purpose. It is
// provided "as is" without express or implied warranty.
//
// See http://www.boost.org for most recent version including documentation.
#ifndef BOOST_THREAD_CLEANUP_MJM012402_HPP
#define BOOST_THREAD_CLEANUP_MJM012402_HPP
namespace boost {
namespace threads {
namespace mac {
namespace detail {
void do_thread_startup();
void do_thread_cleanup();
void set_thread_cleanup_task();
} // namespace detail
} // namespace mac
} // namespace threads
} // namespace boost
#endif // BOOST_THREAD_CLEANUP_MJM012402_HPP

View File

@@ -6,7 +6,7 @@
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. William E. Kempf makes no representations
// about the suitability of this software for any purpose.
// about the suitability of this software for any purpose.
// It is provided "as is" without express or implied warranty.
#include <boost/thread/mutex.hpp>
@@ -16,6 +16,7 @@
#include <boost/limits.hpp>
#include <stdexcept>
#include <cassert>
#include <new>
#include "timeconv.inl"
#if defined(BOOST_HAS_WINTHREADS)
@@ -23,6 +24,11 @@
# include <time.h>
#elif defined(BOOST_HAS_PTHREADS)
# include <errno.h>
#elif defined(BOOST_HAS_MPTASKS)
# include <MacErrors.h>
# include "mac/init.hpp"
# include "mac/safe.hpp"
#endif
namespace boost {
@@ -30,30 +36,26 @@ namespace boost {
#if defined(BOOST_HAS_WINTHREADS)
mutex::mutex()
{
m_mutex = reinterpret_cast<unsigned long>(CreateMutex(0, 0, 0));
m_mutex = reinterpret_cast<void*>(new(std::nothrow) CRITICAL_SECTION);
if (!m_mutex)
throw thread_resource_error();
InitializeCriticalSection(reinterpret_cast<LPCRITICAL_SECTION>(m_mutex));
}
mutex::~mutex()
{
int res = 0;
res = CloseHandle(reinterpret_cast<HANDLE>(m_mutex));
assert(res);
DeleteCriticalSection(reinterpret_cast<LPCRITICAL_SECTION>(m_mutex));
delete reinterpret_cast<LPCRITICAL_SECTION>(m_mutex);
}
void mutex::do_lock()
{
int res = 0;
res = WaitForSingleObject(reinterpret_cast<HANDLE>(m_mutex), INFINITE);
assert(res == WAIT_OBJECT_0);
EnterCriticalSection(reinterpret_cast<LPCRITICAL_SECTION>(m_mutex));
}
void mutex::do_unlock()
{
int res = 0;
res = ReleaseMutex(reinterpret_cast<HANDLE>(m_mutex));
assert(res);
LeaveCriticalSection(reinterpret_cast<LPCRITICAL_SECTION>(m_mutex));
}
void mutex::do_lock(cv_state&)
@@ -68,7 +70,7 @@ void mutex::do_unlock(cv_state&)
try_mutex::try_mutex()
{
m_mutex = reinterpret_cast<unsigned long>(CreateMutex(0, 0, 0));
m_mutex = reinterpret_cast<void*>(CreateMutex(0, 0, 0));
if (!m_mutex)
throw thread_resource_error();
}
@@ -89,7 +91,7 @@ void try_mutex::do_lock()
bool try_mutex::do_trylock()
{
int res = 0;
unsigned int res = 0;
res = WaitForSingleObject(reinterpret_cast<HANDLE>(m_mutex), 0);
assert(res != WAIT_FAILED && res != WAIT_ABANDONED);
return res == WAIT_OBJECT_0;
@@ -114,7 +116,7 @@ void try_mutex::do_unlock(cv_state&)
timed_mutex::timed_mutex()
{
m_mutex = reinterpret_cast<unsigned long>(CreateMutex(0, 0, 0));
m_mutex = reinterpret_cast<void*>(CreateMutex(0, 0, 0));
if (!m_mutex)
throw thread_resource_error();
}
@@ -135,7 +137,7 @@ void timed_mutex::do_lock()
bool timed_mutex::do_trylock()
{
int res = 0;
unsigned int res = 0;
res = WaitForSingleObject(reinterpret_cast<HANDLE>(m_mutex), 0);
assert(res != WAIT_FAILED && res != WAIT_ABANDONED);
return res == WAIT_OBJECT_0;
@@ -146,7 +148,7 @@ bool timed_mutex::do_timedlock(const xtime& xt)
unsigned milliseconds;
to_duration(xt, milliseconds);
int res = WaitForSingleObject(reinterpret_cast<HANDLE>(m_mutex), milliseconds);
unsigned int res = WaitForSingleObject(reinterpret_cast<HANDLE>(m_mutex), milliseconds);
assert(res != WAIT_FAILED && res != WAIT_ABANDONED);
return res == WAIT_OBJECT_0;
}
@@ -199,7 +201,7 @@ void mutex::do_unlock()
assert(res == 0);
}
void mutex::do_lock(cv_state& state)
void mutex::do_lock(cv_state&)
{
}
@@ -248,7 +250,7 @@ void try_mutex::do_unlock()
assert(res == 0);
}
void try_mutex::do_lock(cv_state& state)
void try_mutex::do_lock(cv_state&)
{
}
@@ -338,7 +340,7 @@ bool timed_mutex::do_timedlock(const xtime& xt)
if (res == ETIMEDOUT)
break;
}
bool ret = false;
if (!m_locked)
{
@@ -367,7 +369,7 @@ void timed_mutex::do_unlock()
assert(res == 0);
}
void timed_mutex::do_lock(cv_state& state)
void timed_mutex::do_lock(cv_state&)
{
int res = 0;
while (m_locked)
@@ -397,6 +399,134 @@ void timed_mutex::do_unlock(cv_state& state)
state.pmutex = &m_mutex;
}
#elif defined(BOOST_HAS_MPTASKS)
using threads::mac::detail::safe_enter_critical_region;
mutex::mutex()
{
}
mutex::~mutex()
{
}
void mutex::do_lock()
{
OSStatus lStatus = noErr;
lStatus = safe_enter_critical_region(m_mutex, kDurationForever, m_mutex_mutex);
assert(lStatus == noErr);
}
void mutex::do_unlock()
{
OSStatus lStatus = noErr;
lStatus = MPExitCriticalRegion(m_mutex);
assert(lStatus == noErr);
}
void mutex::do_lock(cv_state& /*state*/)
{
do_lock();
}
void mutex::do_unlock(cv_state& /*state*/)
{
do_unlock();
}
try_mutex::try_mutex()
{
}
try_mutex::~try_mutex()
{
}
void try_mutex::do_lock()
{
OSStatus lStatus = noErr;
lStatus = safe_enter_critical_region(m_mutex, kDurationForever, m_mutex_mutex);
assert(lStatus == noErr);
}
bool try_mutex::do_trylock()
{
OSStatus lStatus = noErr;
lStatus = MPEnterCriticalRegion(m_mutex, kDurationImmediate);
assert(lStatus == noErr || lStatus == kMPTimeoutErr);
return lStatus == noErr;
}
void try_mutex::do_unlock()
{
OSStatus lStatus = noErr;
lStatus = MPExitCriticalRegion(m_mutex);
assert(lStatus == noErr);
}
void try_mutex::do_lock(cv_state& /*state*/)
{
do_lock();
}
void try_mutex::do_unlock(cv_state& /*state*/)
{
do_unlock();
}
timed_mutex::timed_mutex()
{
}
timed_mutex::~timed_mutex()
{
}
void timed_mutex::do_lock()
{
OSStatus lStatus = noErr;
lStatus = safe_enter_critical_region(m_mutex, kDurationForever, m_mutex_mutex);
assert(lStatus == noErr);
}
bool timed_mutex::do_trylock()
{
OSStatus lStatus = noErr;
lStatus = MPEnterCriticalRegion(m_mutex, kDurationImmediate);
assert(lStatus == noErr || lStatus == kMPTimeoutErr);
return(lStatus == noErr);
}
bool timed_mutex::do_timedlock(const xtime& xt)
{
unsigned microseconds;
to_microduration(xt, microseconds);
Duration lDuration = kDurationMicrosecond * microseconds;
OSStatus lStatus = noErr;
lStatus = safe_enter_critical_region(m_mutex, lDuration, m_mutex_mutex);
assert(lStatus == noErr || lStatus == kMPTimeoutErr);
return(lStatus == noErr);
}
void timed_mutex::do_unlock()
{
OSStatus lStatus = noErr;
lStatus = MPExitCriticalRegion(m_mutex);
assert(lStatus == noErr);
}
void timed_mutex::do_lock(cv_state& /*state*/)
{
do_lock();
}
void timed_mutex::do_unlock(cv_state& /*state*/)
{
do_unlock();
}
#endif
} // namespace boost

View File

@@ -6,7 +6,7 @@
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. William E. Kempf makes no representations
// about the suitability of this software for any purpose.
// about the suitability of this software for any purpose.
// It is provided "as is" without express or implied warranty.
#include <boost/thread/once.hpp>
@@ -15,6 +15,21 @@
#if defined(BOOST_HAS_WINTHREADS)
# include <windows.h>
# if defined(BOOST_NO_STRINGSTREAM)
# include <strstream>
class unfreezer
{
public:
unfreezer(std::ostrstream& s) : m_stream(s) {}
~unfreezer() { m_stream.freeze(false); }
private:
std::ostrstream& m_stream;
};
# else
# include <sstream>
# endif
#elif defined(BOOST_HAS_MPTASKS)
# include <Multiprocessing.h>
#endif
#ifdef BOOST_NO_STDC_NAMESPACE
@@ -38,10 +53,23 @@ static void key_init()
static void do_once()
{
once_callback cb = reinterpret_cast<once_callback>(pthread_getspecific(key));
(*cb)();
once_callback* cb = reinterpret_cast<once_callback*>(pthread_getspecific(key));
(**cb)();
}
}
#elif defined(BOOST_HAS_MPTASKS)
void *remote_call_proxy(void *pData)
{
std::pair<void (*)(), boost::once_flag *> &rData(*reinterpret_cast<std::pair<void (*)(), boost::once_flag *> *>(pData));
if(*rData.second == false)
{
rData.first();
*rData.second = true;
}
return(NULL);
}
#endif
@@ -55,11 +83,18 @@ void call_once(void (*func)(), once_flag& flag)
// Memory barrier would be needed here to prevent race conditions on some platforms with
// partial ordering.
if (!tmp)
{
char name[41];
std::sprintf(name, "2AC1A572DB6944B0A65C38C4140AF2F4%X%X", GetCurrentProcessId(), &flag);
HANDLE mutex = CreateMutex(NULL, FALSE, name);
if (!tmp)
{
#if defined(BOOST_NO_STRINGSTREAM)
std::ostrstream strm;
strm << "2AC1A572DB6944B0A65C38C4140AF2F4" << std::hex << GetCurrentProcessId() << &flag << std::ends;
unfreezer unfreeze(strm);
HANDLE mutex = CreateMutex(NULL, FALSE, strm.str());
#else
std::ostringstream strm;
strm << "2AC1A572DB6944B0A65C38C4140AF2F4" << std::hex << GetCurrentProcessId() << &flag;
HANDLE mutex = CreateMutex(NULL, FALSE, strm.str().c_str());
#endif
assert(mutex != NULL);
int res = 0;
@@ -67,26 +102,34 @@ void call_once(void (*func)(), once_flag& flag)
assert(res == WAIT_OBJECT_0);
tmp = flag;
if (!tmp)
{
func();
if (!tmp)
{
func();
tmp = true;
// Memory barrier would be needed here to prevent race conditions on some platforms
// with partial ordering.
flag = tmp;
}
flag = tmp;
}
res = ReleaseMutex(mutex);
res = ReleaseMutex(mutex);
assert(res);
res = CloseHandle(mutex);
assert(res);
}
}
#elif defined(BOOST_HAS_PTHREADS)
pthread_once(&once, &key_init);
pthread_setspecific(key, func);
pthread_once(&flag, do_once);
pthread_setspecific(key, &func);
pthread_once(&flag, do_once);
#elif defined(BOOST_HAS_MPTASKS)
if(flag == false)
{
// all we do here is make a remote call to blue, as blue is not reentrant.
std::pair<void (*)(), once_flag *> sData(func, &flag);
MPRemoteCall(remote_call_proxy, &sData, kMPOwningProcessRemoteContext);
assert(flag == true);
}
#endif
}

View File

@@ -6,11 +6,11 @@
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. William E. Kempf makes no representations
// about the suitability of this software for any purpose.
// about the suitability of this software for any purpose.
// It is provided "as is" without express or implied warranty.
#include <boost/thread/recursive_mutex.hpp>
#include <boost/thread/xtime.hpp>
#include <boost/thread/xtime.hpp>
#include <boost/thread/thread.hpp>
#include <boost/limits.hpp>
#include <stdexcept>
@@ -22,6 +22,9 @@
# include <time.h>
#elif defined(BOOST_HAS_PTHREADS)
# include <errno.h>
#elif defined(BOOST_HAS_MPTASKS)
# include <MacErrors.h>
# include "safe.hpp"
#endif
namespace boost {
@@ -30,47 +33,35 @@ namespace boost {
recursive_mutex::recursive_mutex()
: m_count(0)
{
m_mutex = reinterpret_cast<unsigned long>(CreateMutex(0, 0, 0));
m_mutex = reinterpret_cast<void*>(new(std::nothrow) CRITICAL_SECTION);
if (!m_mutex)
throw thread_resource_error();
InitializeCriticalSection(reinterpret_cast<LPCRITICAL_SECTION>(m_mutex));
}
recursive_mutex::~recursive_mutex()
{
int res = 0;
res = CloseHandle(reinterpret_cast<HANDLE>(m_mutex));
assert(res);
DeleteCriticalSection(reinterpret_cast<LPCRITICAL_SECTION>(m_mutex));
delete reinterpret_cast<LPCRITICAL_SECTION>(m_mutex);
}
void recursive_mutex::do_lock()
{
int res = 0;
res = WaitForSingleObject(reinterpret_cast<HANDLE>(m_mutex), INFINITE);
assert(res == WAIT_OBJECT_0);
EnterCriticalSection(reinterpret_cast<LPCRITICAL_SECTION>(m_mutex));
if (++m_count > 1)
{
res = ReleaseMutex(reinterpret_cast<HANDLE>(m_mutex));
assert(res);
}
LeaveCriticalSection(reinterpret_cast<LPCRITICAL_SECTION>(m_mutex));
}
void recursive_mutex::do_unlock()
{
if (--m_count == 0)
{
int res = 0;
res = ReleaseMutex(reinterpret_cast<HANDLE>(m_mutex));
assert(res);
}
LeaveCriticalSection(reinterpret_cast<LPCRITICAL_SECTION>(m_mutex));
}
void recursive_mutex::do_lock(cv_state& state)
{
int res = 0;
res = WaitForSingleObject(reinterpret_cast<HANDLE>(m_mutex), INFINITE);
assert(res == WAIT_OBJECT_0);
EnterCriticalSection(reinterpret_cast<LPCRITICAL_SECTION>(m_mutex));
m_count = state;
}
@@ -78,16 +69,13 @@ void recursive_mutex::do_unlock(cv_state& state)
{
state = m_count;
m_count = 0;
int res = 0;
res = ReleaseMutex(reinterpret_cast<HANDLE>(m_mutex));
assert(res);
LeaveCriticalSection(reinterpret_cast<LPCRITICAL_SECTION>(m_mutex));
}
recursive_try_mutex::recursive_try_mutex()
: m_count(0)
{
m_mutex = reinterpret_cast<unsigned long>(CreateMutex(0, 0, 0));
m_mutex = reinterpret_cast<void*>(CreateMutex(0, 0, 0));
if (!m_mutex)
throw thread_resource_error();
}
@@ -114,7 +102,7 @@ void recursive_try_mutex::do_lock()
bool recursive_try_mutex::do_trylock()
{
int res = 0;
unsigned int res = 0;
res = WaitForSingleObject(reinterpret_cast<HANDLE>(m_mutex), 0);
assert(res != WAIT_FAILED && res != WAIT_ABANDONED);
@@ -162,7 +150,7 @@ void recursive_try_mutex::do_unlock(cv_state& state)
recursive_timed_mutex::recursive_timed_mutex()
: m_count(0)
{
m_mutex = reinterpret_cast<unsigned long>(CreateMutex(0, 0, 0));
m_mutex = reinterpret_cast<void*>(CreateMutex(0, 0, 0));
if (!m_mutex)
throw thread_resource_error();
}
@@ -189,7 +177,7 @@ void recursive_timed_mutex::do_lock()
bool recursive_timed_mutex::do_trylock()
{
int res = 0;
unsigned int res = 0;
res = WaitForSingleObject(reinterpret_cast<HANDLE>(m_mutex), 0);
assert(res != WAIT_FAILED && res != WAIT_ABANDONED);
@@ -210,7 +198,7 @@ bool recursive_timed_mutex::do_timedlock(const xtime& xt)
unsigned milliseconds;
to_duration(xt, milliseconds);
int res = 0;
unsigned int res = 0;
res = WaitForSingleObject(reinterpret_cast<HANDLE>(m_mutex), milliseconds);
assert(res != WAIT_FAILED && res != WAIT_ABANDONED);
@@ -249,7 +237,7 @@ void recursive_timed_mutex::do_unlock(cv_state& state)
{
state = m_count;
m_count = 0;
int res = 0;
res = ReleaseMutex(reinterpret_cast<HANDLE>(m_mutex));
assert(res);
@@ -610,7 +598,7 @@ recursive_timed_mutex::recursive_timed_mutex()
res = pthread_mutex_init(&m_mutex, 0);
if (res != 0)
throw thread_resource_error();
res = pthread_cond_init(&m_unlocked, 0);
if (res != 0)
{
@@ -706,7 +694,7 @@ bool recursive_timed_mutex::do_timedlock(const xtime& xt)
break;
assert(res == 0);
}
if (!m_valid_id)
{
m_thread_id = tid;
@@ -781,6 +769,221 @@ void recursive_timed_mutex::do_unlock(cv_state& state)
state.pmutex = &m_mutex;
state.count = m_count;
}
#elif defined(BOOST_HAS_MPTASKS)
using threads::mac::detail::safe_enter_critical_region;
recursive_mutex::recursive_mutex()
: m_count(0)
{
}
recursive_mutex::~recursive_mutex()
{
}
void recursive_mutex::do_lock()
{
OSStatus lStatus = noErr;
lStatus = safe_enter_critical_region(m_mutex, kDurationForever, m_mutex_mutex);
assert(lStatus == noErr);
if (++m_count > 1)
{
lStatus = MPExitCriticalRegion(m_mutex);
assert(lStatus == noErr);
}
}
void recursive_mutex::do_unlock()
{
if (--m_count == 0)
{
OSStatus lStatus = noErr;
lStatus = MPExitCriticalRegion(m_mutex);
assert(lStatus == noErr);
}
}
void recursive_mutex::do_lock(cv_state& state)
{
OSStatus lStatus = noErr;
lStatus = safe_enter_critical_region(m_mutex, kDurationForever, m_mutex_mutex);
assert(lStatus == noErr);
m_count = state;
}
void recursive_mutex::do_unlock(cv_state& state)
{
state = m_count;
m_count = 0;
OSStatus lStatus = noErr;
lStatus = MPExitCriticalRegion(m_mutex);
assert(lStatus == noErr);
}
recursive_try_mutex::recursive_try_mutex()
: m_count(0)
{
}
recursive_try_mutex::~recursive_try_mutex()
{
}
void recursive_try_mutex::do_lock()
{
OSStatus lStatus = noErr;
lStatus = safe_enter_critical_region(m_mutex, kDurationForever, m_mutex_mutex);
assert(lStatus == noErr);
if (++m_count > 1)
{
lStatus = MPExitCriticalRegion(m_mutex);
assert(lStatus == noErr);
}
}
bool recursive_try_mutex::do_trylock()
{
OSStatus lStatus = noErr;
lStatus = MPEnterCriticalRegion(m_mutex, kDurationImmediate);
assert(lStatus == noErr || lStatus == kMPTimeoutErr);
if (lStatus == noErr)
{
if (++m_count > 1)
{
lStatus = MPExitCriticalRegion(m_mutex);
assert(lStatus == noErr);
}
return true;
}
return false;
}
void recursive_try_mutex::do_unlock()
{
if (--m_count == 0)
{
OSStatus lStatus = noErr;
lStatus = MPExitCriticalRegion(m_mutex);
assert(lStatus == noErr);
}
}
void recursive_try_mutex::do_lock(cv_state& state)
{
OSStatus lStatus = noErr;
lStatus = safe_enter_critical_region(m_mutex, kDurationForever, m_mutex_mutex);
assert(lStatus == noErr);
m_count = state;
}
void recursive_try_mutex::do_unlock(cv_state& state)
{
state = m_count;
m_count = 0;
OSStatus lStatus = noErr;
lStatus = MPExitCriticalRegion(m_mutex);
assert(lStatus == noErr);
}
recursive_timed_mutex::recursive_timed_mutex()
: m_count(0)
{
}
recursive_timed_mutex::~recursive_timed_mutex()
{
}
void recursive_timed_mutex::do_lock()
{
OSStatus lStatus = noErr;
lStatus = safe_enter_critical_region(m_mutex, kDurationForever, m_mutex_mutex);
assert(lStatus == noErr);
if (++m_count > 1)
{
lStatus = MPExitCriticalRegion(m_mutex);
assert(lStatus == noErr);
}
}
bool recursive_timed_mutex::do_trylock()
{
OSStatus lStatus = noErr;
lStatus = MPEnterCriticalRegion(m_mutex, kDurationImmediate);
assert(lStatus == noErr || lStatus == kMPTimeoutErr);
if (lStatus == noErr)
{
if (++m_count > 1)
{
lStatus = MPExitCriticalRegion(m_mutex);
assert(lStatus == noErr);
}
return true;
}
return false;
}
bool recursive_timed_mutex::do_timedlock(const xtime& xt)
{
unsigned microseconds;
to_microduration(xt, microseconds);
Duration lDuration = kDurationMicrosecond * microseconds;
OSStatus lStatus = noErr;
lStatus = safe_enter_critical_region(m_mutex, lDuration, m_mutex_mutex);
assert(lStatus == noErr || lStatus == kMPTimeoutErr);
if (lStatus == noErr)
{
if (++m_count > 1)
{
lStatus = MPExitCriticalRegion(m_mutex);
assert(lStatus == noErr);
}
return true;
}
return false;
}
void recursive_timed_mutex::do_unlock()
{
if (--m_count == 0)
{
OSStatus lStatus = noErr;
lStatus = MPExitCriticalRegion(m_mutex);
assert(lStatus == noErr);
}
}
void recursive_timed_mutex::do_lock(cv_state& state)
{
OSStatus lStatus = noErr;
lStatus = safe_enter_critical_region(m_mutex, kDurationForever, m_mutex_mutex);
assert(lStatus == noErr);
m_count = state;
}
void recursive_timed_mutex::do_unlock(cv_state& state)
{
state = m_count;
m_count = 0;
OSStatus lStatus = noErr;
lStatus = MPExitCriticalRegion(m_mutex);
assert(lStatus == noErr);
}
#endif
} // namespace boost

View File

@@ -1,179 +0,0 @@
// Copyright (C) 2001
// William E. Kempf
//
// Permission to use, copy, modify, distribute and sell this software
// and its documentation for any purpose is hereby granted without fee,
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. William E. Kempf makes no representations
// about the suitability of this software for any purpose.
// It is provided "as is" without express or implied warranty.
#include <boost/thread/semaphore.hpp>
#include <boost/thread/xtime.hpp>
#include <boost/limits.hpp>
#include <boost/thread/exceptions.hpp>
#include <stdexcept>
#include <cassert>
#include "timeconv.inl"
#if defined(BOOST_HAS_WINTHREADS)
# include <windows.h>
#elif defined(BOOST_HAS_PTHREADS)
# include <pthread.h>
# include <errno.h>
# include <boost/thread/mutex.hpp>
# include <boost/thread/condition.hpp>
#endif
namespace boost {
#if defined(BOOST_HAS_WINTHREADS)
semaphore::semaphore(unsigned count, unsigned max)
{
if (static_cast<long>(max) <= 0)
max = std::numeric_limits<long>::max();
m_sema = reinterpret_cast<unsigned long>(CreateSemaphore(0, count, max, 0));
if (!m_sema)
throw thread_resource_error();
}
semaphore::~semaphore()
{
int res = 0;
res = CloseHandle(reinterpret_cast<HANDLE>(m_sema));
assert(res);
}
bool semaphore::up(unsigned count, unsigned* prev)
{
long p;
bool ret = !!ReleaseSemaphore(reinterpret_cast<HANDLE>(m_sema), count, &p);
if (prev)
*prev = p;
return ret;
}
void semaphore::down()
{
int res = 0;
res = WaitForSingleObject(reinterpret_cast<HANDLE>(m_sema), INFINITE);
assert(res == WAIT_OBJECT_0);
}
bool semaphore::down(const xtime& xt)
{
unsigned milliseconds;
to_duration(xt, milliseconds);
int res = 0;
res = WaitForSingleObject(reinterpret_cast<HANDLE>(m_sema), milliseconds);
assert(res != WAIT_FAILED && res != WAIT_ABANDONED);
return res == WAIT_OBJECT_0;
}
#elif defined(BOOST_HAS_PTHREADS)
semaphore::semaphore(unsigned count, unsigned max)
: m_available(count), m_max(max ? max : std::numeric_limits<unsigned>::max())
{
int res = 0;
res = pthread_mutex_init(&m_mutex, 0);
if (res != 0)
throw thread_resource_error();
res = pthread_cond_init(&m_condition, 0);
if (res != 0)
{
pthread_mutex_destroy(&m_mutex);
throw thread_resource_error();
}
}
semaphore::~semaphore()
{
int res = 0;
res = pthread_mutex_destroy(&m_mutex);
assert(res == 0);
res = pthread_cond_destroy(&m_condition);
assert(res == 0);
}
bool semaphore::up(unsigned count, unsigned* prev)
{
int res = 0;
res = pthread_mutex_lock(&m_mutex);
assert(res == 0);
if (prev)
*prev = m_available;
if (m_available + count > m_max)
{
res = pthread_mutex_unlock(&m_mutex);
assert(res == 0);
return false;
}
m_available += count;
res = pthread_cond_broadcast(&m_condition);
assert(res == 0);
res = pthread_mutex_unlock(&m_mutex);
assert(res == 0);
return true;
}
void semaphore::down()
{
int res = 0;
res = pthread_mutex_lock(&m_mutex);
assert(res == 0);
while (m_available == 0)
{
res = pthread_cond_wait(&m_condition, &m_mutex);
assert(res == 0);
}
m_available--;
res = pthread_mutex_unlock(&m_mutex);
assert(res == 0);
}
bool semaphore::down(const xtime& xt)
{
int res = 0;
res = pthread_mutex_lock(&m_mutex);
assert(res == 0);
timespec ts;
to_timespec(xt, ts);
while (m_available == 0)
{
res = pthread_cond_timedwait(&m_condition, &m_mutex, &ts);
assert(res == 0 || res == ETIMEDOUT);
if (res == ETIMEDOUT)
{
res = pthread_mutex_unlock(&m_mutex);
assert(res == 0);
return false;
}
}
m_available--;
res = pthread_mutex_unlock(&m_mutex);
assert(res == 0);
return true;
}
#endif
} // namespace boost
// Change Log:
// 8 Feb 01 WEKEMPF Initial version.
// 22 May 01 WEKEMPF Modified to use xtime for time outs.

View File

@@ -6,11 +6,10 @@
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. William E. Kempf makes no representations
// about the suitability of this software for any purpose.
// about the suitability of this software for any purpose.
// It is provided "as is" without express or implied warranty.
#include <boost/thread/thread.hpp>
#include <boost/thread/semaphore.hpp>
#include <boost/thread/xtime.hpp>
#include <boost/thread/condition.hpp>
#include <cassert>
@@ -18,6 +17,12 @@
#if defined(BOOST_HAS_WINTHREADS)
# include <windows.h>
# include <process.h>
#elif defined(BOOST_HAS_MPTASKS)
# include <DriverServices.h>
# include "init.hpp"
# include "safe.hpp"
# include <boost/thread/tss.hpp>
#endif
#include "timeconv.inl"
@@ -54,6 +59,8 @@ extern "C" {
unsigned __stdcall thread_proxy(void* param)
#elif defined(BOOST_HAS_PTHREADS)
static void* thread_proxy(void* param)
#elif defined(BOOST_HAS_MPTASKS)
static OSStatus thread_proxy(void* param)
#endif
{
try
@@ -66,6 +73,9 @@ static void* thread_proxy(void* param)
catch (...)
{
}
#if defined(BOOST_HAS_MPTASKS)
::boost::detail::thread_cleanup();
#endif
return 0;
}
@@ -77,10 +87,15 @@ thread::thread()
: m_joinable(false)
{
#if defined(BOOST_HAS_WINTHREADS)
m_thread = reinterpret_cast<unsigned long>(GetCurrentThread());
m_thread = reinterpret_cast<void*>(GetCurrentThread());
m_id = GetCurrentThreadId();
#elif defined(BOOST_HAS_PTHREADS)
m_thread = pthread_self();
#elif defined(BOOST_HAS_MPTASKS)
threads::mac::detail::thread_init();
threads::mac::detail::create_singletons();
m_pTaskID = MPCurrentTaskID();
m_pJoinQueueID = kInvalidID;
#endif
}
@@ -89,7 +104,7 @@ thread::thread(const function0<void>& threadfunc)
{
thread_param param(threadfunc);
#if defined(BOOST_HAS_WINTHREADS)
m_thread = _beginthreadex(0, 0, &thread_proxy, &param, 0, &m_id);
m_thread = reinterpret_cast<void*>(_beginthreadex(0, 0, &thread_proxy, &param, 0, &m_id));
if (!m_thread)
throw thread_resource_error();
#elif defined(BOOST_HAS_PTHREADS)
@@ -97,6 +112,25 @@ thread::thread(const function0<void>& threadfunc)
res = pthread_create(&m_thread, 0, &thread_proxy, &param);
if (res != 0)
throw thread_resource_error();
#elif defined(BOOST_HAS_MPTASKS)
threads::mac::detail::thread_init();
threads::mac::detail::create_singletons();
OSStatus lStatus = noErr;
m_pJoinQueueID = kInvalidID;
m_pTaskID = kInvalidID;
lStatus = MPCreateQueue(&m_pJoinQueueID);
if(lStatus != noErr) throw thread_resource_error();
lStatus = MPCreateTask(&thread_proxy, &param, 0UL, m_pJoinQueueID, NULL, NULL,
0UL, &m_pTaskID);
if(lStatus != noErr)
{
lStatus = MPDeleteQueue(m_pJoinQueueID);
assert(lStatus == noErr);
throw thread_resource_error();
}
#endif
param.wait();
}
@@ -111,6 +145,10 @@ thread::~thread()
assert(res);
#elif defined(BOOST_HAS_PTHREADS)
pthread_detach(m_thread);
#elif defined(BOOST_HAS_MPTASKS)
assert(m_pJoinQueueID != kInvalidID);
OSStatus lStatus = MPDeleteQueue(m_pJoinQueueID);
assert(lStatus == noErr);
#endif
}
}
@@ -121,6 +159,8 @@ bool thread::operator==(const thread& other) const
return other.m_id == m_id;
#elif defined(BOOST_HAS_PTHREADS)
return pthread_equal(m_thread, other.m_thread) != 0;
#elif defined(BOOST_HAS_MPTASKS)
return other.m_pTaskID == m_pTaskID;
#endif
}
@@ -140,6 +180,9 @@ void thread::join()
#elif defined(BOOST_HAS_PTHREADS)
res = pthread_join(m_thread, 0);
assert(res == 0);
#elif defined(BOOST_HAS_MPTASKS)
OSStatus lStatus = threads::mac::detail::safe_wait_on_queue(m_pJoinQueueID, NULL, NULL, NULL, kDurationForever);
assert(lStatus == noErr);
#endif
// This isn't a race condition since any race that could occur would
// have us in undefined behavior territory any way.
@@ -163,13 +206,21 @@ void thread::sleep(const xtime& xt)
timespec ts;
to_timespec_duration(xt, ts);
// nanosleep takes a timespec that is an offset, not
// an absolute time.
// nanosleep takes a timespec that is an offset, not
// an absolute time.
nanosleep(&ts, 0);
# else
semaphore sema;
sema.down(xt);
mutex mx;
mutex::scoped_lock lock(mx);
condition cond;
cond.timed_wait(lock, xt);
# endif
#elif defined(BOOST_HAS_MPTASKS)
unsigned microseconds;
to_microduration(xt, microseconds);
Duration lMicroseconds(kDurationMicrosecond * microseconds);
AbsoluteTime sWakeTime(DurationToAbsolute(lMicroseconds));
threads::mac::detail::safe_delay_until(&sWakeTime);
#endif
}
@@ -191,6 +242,8 @@ void thread::yield()
xtime_get(&xt, TIME_UTC);
sleep(xt);
# endif
#elif defined(BOOST_HAS_MPTASKS)
MPYield();
#endif
}

View File

@@ -4,10 +4,15 @@
#define BOOST_THREADMON_EXPORTS
#include "threadmon.hpp"
#define WIN32_LEAN_AND_MEAN // Exclude rarely-used stuff from Windows headers
#ifdef BOOST_HAS_WINTHREADS
#define WIN32_LEAN_AND_MEAN // Exclude rarely-used stuff from Windows headers
#include <windows.h>
#pragma warning(disable : 4786)
#ifdef BOOST_MSVC
# pragma warning(disable : 4786)
#endif
#include <list>
#include <set>
#include <algorithm>
@@ -30,14 +35,14 @@ namespace
BOOL APIENTRY DllMain(HANDLE module, DWORD reason, LPVOID)
{
switch (reason)
{
case DLL_PROCESS_ATTACH:
{
case DLL_PROCESS_ATTACH:
InitializeCriticalSection(&cs);
key = TlsAlloc();
break;
case DLL_THREAD_ATTACH:
case DLL_THREAD_ATTACH:
break;
case DLL_THREAD_DETACH:
case DLL_THREAD_DETACH:
{
// Call the thread's exit handlers.
exit_handlers* handlers = static_cast<exit_handlers*>(TlsGetValue(key));
@@ -54,7 +59,7 @@ BOOL APIENTRY DllMain(HANDLE module, DWORD reason, LPVOID)
}
}
break;
case DLL_PROCESS_DETACH:
case DLL_PROCESS_DETACH:
{
// Assume the main thread is ending (call its handlers) and all other threads
// have already ended. If this DLL is loaded and unloaded dynamically at run time
@@ -76,7 +81,7 @@ BOOL APIENTRY DllMain(HANDLE module, DWORD reason, LPVOID)
DeleteCriticalSection(&cs);
TlsFree(key);
}
break;
break;
}
return TRUE;
}
@@ -136,3 +141,5 @@ int on_thread_exit(void (__cdecl * func)(void))
return 0;
}
#endif // BOOST_HAS_WINTHREADS

View File

@@ -1,10 +1,17 @@
#include <boost/config.hpp>
#ifndef BOOST_HAS_THREADS
# error Thread support is unavailable!
#endif
// The following ifdef block is the standard way of creating macros which make exporting
#ifdef BOOST_HAS_WINTHREADS
// The following ifdef block is the standard way of creating macros which make exporting
// from a DLL simpler. All files within this DLL are compiled with the BOOST_THREADMON_EXPORTS
// symbol defined on the command line. this symbol should not be defined on any project
// that uses this DLL. This way any other project whose source files include this file see
// that uses this DLL. This way any other project whose source files include this file see
// BOOST_THREADMON_API functions as being imported from a DLL, wheras this DLL sees symbols
// defined with this macro as being exported.
#ifdef BOOST_THREADMON_EXPORTS
#define BOOST_THREADMON_API __declspec(dllexport)
#else
@@ -12,3 +19,5 @@
#endif
extern "C" BOOST_THREADMON_API int on_thread_exit(void (__cdecl * func)(void));
#endif // BOOST_HAS_WINTHREADS

View File

@@ -6,14 +6,17 @@
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. William E. Kempf makes no representations
// about the suitability of this software for any purpose.
// about the suitability of this software for any purpose.
// It is provided "as is" without express or implied warranty.
namespace {
const unsigned MILLISECONDS_PER_SECOND = 1000;
const unsigned NANOSECONDS_PER_SECOND = 1000000000;
const unsigned NANOSECONDS_PER_MILLISECOND = 1000000;
const unsigned MICROSECONDS_PER_SECOND = 1000000;
const unsigned NANOSECONDS_PER_MICROSECOND = 1000;
inline void to_time(unsigned milliseconds, boost::xtime& xt)
{
int res = 0;
@@ -23,7 +26,7 @@ namespace {
xt.sec += (milliseconds / MILLISECONDS_PER_SECOND);
xt.nsec += ((milliseconds % MILLISECONDS_PER_SECOND) * NANOSECONDS_PER_MILLISECOND);
if (xt.nsec > NANOSECONDS_PER_SECOND)
if (xt.nsec > static_cast<const int>(NANOSECONDS_PER_SECOND))
{
++xt.sec;
xt.nsec -= NANOSECONDS_PER_SECOND;
@@ -35,6 +38,11 @@ namespace {
{
ts.tv_sec = static_cast<int>(xt.sec);
ts.tv_nsec = static_cast<int>(xt.nsec);
if(ts.tv_nsec > static_cast<const int>(NANOSECONDS_PER_SECOND))
{
ts.tv_sec += ts.tv_nsec / NANOSECONDS_PER_SECOND;
ts.tv_nsec %= NANOSECONDS_PER_SECOND;
}
}
inline void to_time(unsigned milliseconds, timespec& ts)
@@ -66,6 +74,11 @@ namespace {
ts.tv_sec -= 1;
ts.tv_nsec += NANOSECONDS_PER_SECOND;
}
if(ts.tv_nsec > static_cast<const int>(NANOSECONDS_PER_SECOND))
{
ts.tv_sec += ts.tv_nsec / NANOSECONDS_PER_SECOND;
ts.tv_nsec %= NANOSECONDS_PER_SECOND;
}
}
}
#endif
@@ -86,6 +99,23 @@ namespace {
NANOSECONDS_PER_MILLISECOND));
}
}
inline void to_microduration(const boost::xtime& xt, unsigned& microseconds)
{
boost::xtime cur;
int res = 0;
res = boost::xtime_get(&cur, boost::TIME_UTC);
assert(res == boost::TIME_UTC);
if (xt.sec < cur.sec || (xt.sec == cur.sec && xt.nsec < cur.nsec))
microseconds = 0;
else
{
microseconds = static_cast<unsigned long>(((xt.sec - cur.sec) * MICROSECONDS_PER_SECOND) +
(((xt.nsec - cur.nsec) + (NANOSECONDS_PER_MICROSECOND/2)) /
NANOSECONDS_PER_MICROSECOND));
}
}
}
// Change Log:

View File

@@ -6,7 +6,7 @@
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. William E. Kempf makes no representations
// about the suitability of this software for any purpose.
// about the suitability of this software for any purpose.
// It is provided "as is" without express or implied warranty.
#include <boost/thread/tss.hpp>
@@ -27,7 +27,7 @@ namespace {
typedef std::map<int, cleanup_info> cleanup_handlers;
DWORD key;
boost::once_flag once = boost::once_init;
boost::once_flag once = BOOST_ONCE_INIT;
void init_cleanup_key()
{
@@ -72,6 +72,72 @@ namespace {
return handlers;
}
}
#elif defined(BOOST_HAS_MPTASKS)
#include <map>
namespace {
typedef std::pair<void(*)(void*), void*> cleanup_info;
typedef std::map<int, cleanup_info> cleanup_handlers;
TaskStorageIndex key;
boost::once_flag once = BOOST_ONCE_INIT;
void init_cleanup_key()
{
OSStatus lStatus = MPAllocateTaskStorageIndex(&key);
assert(lStatus == noErr);
}
cleanup_handlers* get_handlers()
{
boost::call_once(&init_cleanup_key, once);
cleanup_handlers* handlers = reinterpret_cast<cleanup_handlers*>(MPGetTaskStorageValue(key));
if (!handlers)
{
try
{
handlers = new cleanup_handlers;
}
catch (...)
{
return 0;
}
OSStatus lStatus = noErr;
lStatus = MPSetTaskStorageValue(key, reinterpret_cast<TaskStorageValue>(handlers));
assert(lStatus == noErr);
// TODO - create a generalized mechanism for registering thread exit functions
// and use it here.
}
return handlers;
}
}
namespace boost {
namespace detail {
void thread_cleanup()
{
cleanup_handlers* handlers = reinterpret_cast<cleanup_handlers*>(MPGetTaskStorageValue(key));
if(handlers != NULL)
{
for (cleanup_handlers::iterator it = handlers->begin(); it != handlers->end(); ++it)
{
cleanup_info info = it->second;
if (info.second)
info.first(info.second);
}
delete handlers;
}
}
} // namespace detail
} // namespace boost
#endif
namespace boost { namespace detail {
@@ -106,8 +172,8 @@ bool tss::set(void* value)
assert(handlers);
if (!handlers)
return false;
cleanup_info info(m_cleanup, value);
(*handlers)[m_key] = info;
cleanup_info info(m_cleanup, value);
(*handlers)[m_key] = info;
}
return !!TlsSetValue(m_key, value);
}
@@ -136,6 +202,42 @@ bool tss::set(void* value)
{
return pthread_setspecific(m_key, value) == 0;
}
#elif defined(BOOST_HAS_MPTASKS)
tss::tss(void (*cleanup)(void*))
{
OSStatus lStatus = MPAllocateTaskStorageIndex(&m_key);
if(lStatus != noErr)
throw thread_resource_error();
m_cleanup = cleanup;
}
tss::~tss()
{
OSStatus lStatus = MPDeallocateTaskStorageIndex(m_key);
assert(lStatus == noErr);
}
void* tss::get() const
{
TaskStorageValue ulValue = MPGetTaskStorageValue(m_key);
return(reinterpret_cast<void *>(ulValue));
}
bool tss::set(void* value)
{
if (value && m_cleanup)
{
cleanup_handlers* handlers = get_handlers();
assert(handlers);
if (!handlers)
return false;
cleanup_info info(m_cleanup, value);
(*handlers)[m_key] = info;
}
OSStatus lStatus = MPSetTaskStorageValue(m_key, reinterpret_cast<TaskStorageValue>(value));
return(lStatus == noErr);
}
#endif
} // namespace detail

View File

@@ -6,7 +6,7 @@
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. William E. Kempf makes no representations
// about the suitability of this software for any purpose.
// about the suitability of this software for any purpose.
// It is provided "as is" without express or implied warranty.
#include <boost/thread/xtime.hpp>
@@ -14,11 +14,62 @@
#if defined(BOOST_HAS_FTIME)
# include <windows.h>
#elif defined(BOOST_HAS_GETTIMEOFDAY)
# include <sys/time.h>
# include <sys/time.h>
#elif defined(BOOST_HAS_MPTASKS)
# include <DriverServices.h>
# include <boost/thread/detail/force_cast.hpp>
#endif
namespace boost {
#ifdef BOOST_HAS_MPTASKS
namespace detail
{
using thread::force_cast;
struct startup_time_info
{
startup_time_info()
{
// 1970 Jan 1 at 00:00:00
static const DateTimeRec k_sUNIXBase = {1970, 1, 1, 0, 0, 0, 0};
static unsigned long s_ulUNIXBaseSeconds = 0UL;
if(s_ulUNIXBaseSeconds == 0UL)
{
// calculate the number of seconds between the Mac OS base and the UNIX base
// the first time we enter this constructor.
DateToSeconds(&k_sUNIXBase, &s_ulUNIXBaseSeconds);
}
unsigned long ulSeconds;
// get the time in UpTime units twice, with the time in seconds in the middle.
uint64_t ullFirstUpTime = force_cast<uint64_t>(UpTime());
GetDateTime(&ulSeconds);
uint64_t ullSecondUpTime = force_cast<uint64_t>(UpTime());
// calculate the midpoint of the two UpTimes, and save that.
uint64_t ullAverageUpTime = (ullFirstUpTime + ullSecondUpTime) / 2ULL;
m_sStartupAbsoluteTime = force_cast<AbsoluteTime>(ullAverageUpTime);
// save the number of seconds, recentered at the UNIX base.
m_ulStartupSeconds = ulSeconds - s_ulUNIXBaseSeconds;
}
AbsoluteTime m_sStartupAbsoluteTime;
UInt32 m_ulStartupSeconds;
};
static startup_time_info g_sStartupTimeInfo;
} // namespace detail
#endif
int xtime_get(struct xtime* xtp, int clock_type)
{
if (clock_type == TIME_UTC)
@@ -26,7 +77,7 @@ int xtime_get(struct xtime* xtp, int clock_type)
#if defined(BOOST_HAS_FTIME)
FILETIME ft;
GetSystemTimeAsFileTime(&ft);
const __int64 TIMESPEC_TO_FILETIME_OFFSET = ((__int64)27111902 << 32) + (__int64)3577643008;
const boost::uint64_t TIMESPEC_TO_FILETIME_OFFSET = ((boost::uint64_t)27111902UL << 32) + (boost::uint64_t)3577643008UL;
xtp->sec = (int)((*(__int64*)&ft - TIMESPEC_TO_FILETIME_OFFSET) / 10000000);
xtp->nsec = (int)((*(__int64*)&ft - TIMESPEC_TO_FILETIME_OFFSET -
((__int64)xtp->sec * (__int64)10000000)) * 100);
@@ -43,6 +94,19 @@ int xtime_get(struct xtime* xtp, int clock_type)
xtp->sec = ts.tv_sec;
xtp->nsec = ts.tv_nsec;
return clock_type;
#elif defined(BOOST_HAS_MPTASKS)
using detail::thread::force_cast;
// the Mac OS does not have an MP-safe way of getting the date/time, so we use a
// delta from the startup time. We _could_ defer this and use something that is
// interrupt-safe, but this would be _SLOW_, and we need speed here.
const uint64_t k_ullNanosecondsPerSecond(1000ULL * 1000ULL * 1000ULL);
AbsoluteTime sUpTime(UpTime());
uint64_t ullNanoseconds(force_cast<uint64_t>(AbsoluteDeltaToNanoseconds(sUpTime, detail::g_sStartupTimeInfo.m_sStartupAbsoluteTime)));
uint64_t ullSeconds = (ullNanoseconds / k_ullNanosecondsPerSecond);
ullNanoseconds -= (ullSeconds * k_ullNanosecondsPerSecond);
xtp->sec = detail::g_sStartupTimeInfo.m_ulStartupSeconds + ullSeconds;
xtp->nsec = ullNanoseconds;
return clock_type;
#else
# error "xtime_get implementation undefined"
#endif

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