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171 lines
7.3 KiB
HTML
Executable File
171 lines
7.3 KiB
HTML
Executable File
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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<HTML>
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<HEAD>
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<TITLE>Memory-Mapped Files</TITLE>
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<LINK REL='stylesheet' HREF='../../../../boost.css'>
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<LINK REL='stylesheet' HREF='../theme/iostreams.css'>
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</HEAD>
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<BODY>
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<!-- Begin Banner -->
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<H1 CLASS='title'>Memory-Mapped Files</H1>
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<HR CLASS='banner'>
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<!-- End Banner -->
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<DL class='page-index'>
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<DT><A href='#overview'>Overview</A></DT>
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<DT><A href='#acknowledgments'>Acknowledgments</A></DT>
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<DT><A href='#installation'>Installation</A></DT>
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<DT><A href='#headers'>Headers</A></DT>
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<DT><A href='#reference'>Reference</A>
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<UL>
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<LI CLASS='square'><A href='#mapped_file_source'>Class <CODE>mapped_file_source</CODE></A></LI>
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<LI CLASS='square'><A href='#mapped_file_sink'>Class <CODE>mapped_file_sink</CODE></A></LI>
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<LI CLASS='square'><A href='#mapped_file'>Class <CODE>mapped_file</CODE></A></LI>
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</UL>
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</DT>
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</DL>
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<HR>
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<A NAME='overview'>
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<H2>Overview</H2>
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<P>
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The classes <CODE>mapped_file_source</CODE>, <CODE>mapped_file_sink</CODE> and <CODE>mapped_file</CODE> provide access to memory-mapped files on Windows and POSIX systems. These <A HREF="../concepts.html#device_concepts">Devices</A> behave much like the <A HREF="file.html">File Wrappers</A> <CODE>basic_file_source</CODE>, <CODE>basic_file_sink</CODE> and <CODE>basic_file</CODE>, with the following important differences:
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</P>
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<UL>
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<LI CLASS='square'>Files must exist before being opened, and are never truncated; attempting to write past the end of a file results in an error.
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<LI CLASS='square'>Files are always opened in binary mode.
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<LI CLASS='square'>Wide-character streams are not supported.
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</UL>
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<P>
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Wide-character versions of the memory-mapped file Devices may be defined as follows, using the template <A HREF='converter.html'><CODE>converter</CODE></A>:
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<PRE CLASS='broken_ie'> <SPAN CLASS="preprocessor">#include</SPAN> <A CLASS='header' HREF='../../../../boost/iostreams/converter.hpp'><SPAN CLASS="literal"><boost/iostreams/converter.hpp></SPAN></A>
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<SPAN CLASS="preprocessor">#include</SPAN> <A CLASS='header' HREF='../../../../boost/iostreams/device/mapped_file.hpp'><SPAN CLASS="literal"><boost/iostreams/maped_file.hpp></SPAN></A>
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typedef converter<mapped_file_source> <SPAN CLASS="defined">wmapped_file_source</SPAN>;
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typedef converter<mapped_file_sink> <SPAN CLASS="defined">wmapped_file_sink</SPAN>;</PRE>
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</P>
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<A NAME='acknowledgments'>
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<H2>Acknowledgments</H2>
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<P>
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The memory-mapped file Devices are based on the work of Craig Henderson (<A CLASS='bib_ref' HREF='../bibliography.html#henderson'>[Henderson]</A>).
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</P>
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<A NAME='installation'>
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<H2>Installation</H2>
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<P>
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The memory-mapped file Devices depend on the source file <A CLASS='header' HREF='../../src/mapped_file.cpp'><CODE><libs/iostreams/src/mapped_file.cpp></CODE></A>. This source file makes use of Windows or POSIX headers depending on the user's operating system. For installation instructions see <A HREF='../installation.html'>Installation</A>.
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</P>
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<A NAME='headers'>
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<H2>Headers</H2>
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<DL class='page-index'>
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<DT><A CLASS='header' HREF='../../../../boost/iostreams/device/mapped_file.hpp'><CODE><boost/iostreams/device/mapped_file.hpp></CODE></A></DT>
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</DL>
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<A NAME='reference'>
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<H2>Reference</H2>
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<A NAME='mapped_file_source'>
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<H3>Class <CODE>mapped_file_source</CODE></H3>
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<H4>Description</H4>
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<P>Model of <A HREF='../concepts/source.html'>Source</A> providing read-only access to memory-mapped files on Windows and POSIX systems.</P>
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<H4>Synopsis</H4>
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<PRE CLASS='broken_ie'><SPAN CLASS="keyword">namespace</SPAN> boost { <SPAN CLASS="keyword">namespace</SPAN> iostreams {
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<SPAN CLASS="keyword">class</SPAN> <SPAN CLASS="defined">mapped_file_source</SPAN> : <SPAN CLASS="keyword">public</SPAN> <A CLASS="documented" HREF="device.html#synopsis">source</A> { <SPAN CLASS="comment">// Exposition only</SPAN>
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<SPAN CLASS="keyword">public</SPAN>:
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<A CLASS="documented" HREF="#mapped_file_source_constructor">mapped_file_source</A>(<SPAN CLASS="keyword">const</SPAN> std::string& path);
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<SPAN CLASS='omitted'>...</SPAN>
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};
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} } // End namespace boost::io</PRE>
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<A NAME='mapped_file_source_constructor'></A>
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<H4><CODE>mapped_file_source::mapped_file_source</CODE></H4>
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<PRE CLASS='broken_ie'> mapped_file_source(<SPAN CLASS="keyword">const</SPAN> std::string& path);</PRE>
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<P>Constructs a <CODE>mapped_file_source</CODE> to access the file with the given pathname.</P>
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<A NAME='mapped_file_sink'>
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<H3>Class <CODE>mapped_file_sink</CODE></H3>
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<H4>Description</H4>
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<P>Model of <A HREF='../concepts/sink.html'>Sink</A> providing write-only access to memory-mapped files on Windows and POSIX systems.</P>
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<H4>Synopsis</H4>
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<PRE CLASS='broken_ie'><SPAN CLASS="keyword">namespace</SPAN> boost { <SPAN CLASS="keyword">namespace</SPAN> iostreams {
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<SPAN CLASS="keyword">class</SPAN> <SPAN CLASS="defined">mapped_file_sink</SPAN> : <SPAN CLASS="keyword">public</SPAN> <A CLASS="documented" HREF="device.html#synopsis">sink</A> { <SPAN CLASS="comment">// Exposition only</SPAN>
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<SPAN CLASS="keyword">public</SPAN>:
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<A CLASS="documented" HREF="#mapped_file_sink_constructor">mapped_file_sink</A>(<SPAN CLASS="keyword">const</SPAN> std::string& path);
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<SPAN CLASS='omitted'>...</SPAN>
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};
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} } // End namespace boost::io</PRE>
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<A NAME='mapped_file_sink_constructor'></A>
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<H4><CODE>mapped_file_sink::mapped_file_sink</CODE></H4>
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<PRE CLASS='broken_ie'> mapped_file_sink(<SPAN CLASS="keyword">const</SPAN> std::string& path);</PRE>
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<P>Constructs a <CODE>mapped_file_sink</CODE> to access the file with the given pathname.</P>
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<A NAME='mapped_file'>
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<H3>Class <CODE>mapped_file</CODE></H3>
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<H4>Description</H4>
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<P>Model of <A HREF='../concepts/seekable_device.html'>SeekableDevice</A> providing read-write access to memory-mapped files on Windows and POSIX systems.</P>
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<H4>Synopsis</H4>
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<PRE CLASS='broken_ie'><SPAN CLASS="keyword">namespace</SPAN> boost { <SPAN CLASS="keyword">namespace</SPAN> iostreams {
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<SPAN CLASS="keyword">class</SPAN> <SPAN CLASS="defined">mapped_file</SPAN> : <SPAN CLASS="keyword">public</SPAN> <A CLASS="documented" HREF="device.html#description">device<seekable></A> { <SPAN CLASS="comment">// Exposition only</SPAN>
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<SPAN CLASS="keyword">public</SPAN>:
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<A CLASS="documented" HREF="#mapped_file_constructor">mapped_file</A>(<SPAN CLASS="keyword">const</SPAN> std::string& path);
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<SPAN CLASS='omitted'>...</SPAN>
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};
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} } // End namespace boost::io</PRE>
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<A NAME='mapped_file_constructor'></A>
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<H4><CODE>mapped_file_::mapped_file</CODE></H4>
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<PRE CLASS='broken_ie'> mapped_file(<SPAN CLASS="keyword">const</SPAN> std::string& path);</PRE>
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<P>Constructs a <CODE>mapped_file</CODE> to access the file with the given pathname.</P>
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<!-- Begin Footer -->
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<HR>
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<P CLASS='copyright'>Revised
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<!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->
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20 May, 2004
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<!--webbot bot="Timestamp" endspan i-checksum="38504" -->
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</P>
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<P CLASS='copyright'>© Copyright Jonathan Turkanis, 2004</P>
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<P CLASS='copyright'>
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Distributed under the Boost Software License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at <A HREF='http://www.boost.org/LICENSE_1_0.txt'>http://www.boost.org/LICENSE_1_0.txt</A>)
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</P>
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<!-- End Footer -->
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