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235 lines
10 KiB
HTML
Executable File
235 lines
10 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>File Wrappers</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'>File Wrappers</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='#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='#file_source'>Class template <CODE>basic_file_source</CODE></A></LI>
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<LI CLASS='square'><A href='#file_sink'>Class template <CODE>basic_file_sink</CODE></A></LI>
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<LI CLASS='square'><A href='#file'>Class template <CODE>basic_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 class templates <CODE>basic_file_source</CODE>, <CODE>basic_file_sink</CODE> and <CODE>basic_file</CODE> are wrappers for <CODE>std::basic_filebuf</CODE> which are <A HREF='http://www.boost.org/libs/utility/CopyConstructible.html'>CopyConstructible</A> and <A HREF='http://www.boost.org/libs/utility/Assignable.html'>Assignable</A>. They are useful whenever one wants to access a file without managing the lifetime of a standard file stream or stream buffer. This is because when a stream or stream buffer is added to a <A HREF='filtering_streambuf.html'><CODE>filtering_streambuf</CODE></A> or <A HREF='filtering_stream.html'><CODE>filtering_stream</CODE></A> it is stored as a reference which must remain valid until that stream or stream buffer is removed from the chain.
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</P>
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<P>
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These templates are used extensively by the <A HREF='../portability.html'>regression tests</A> to test <A HREF='../policy_based_streams.html'><CODE>streambuf_facade</CODE></A> and <A HREF='../filtering_streams.html'><CODE>filtering_streambuf</CODE></A>.
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</P>
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<P>
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The most common specializations are accessible via the typedefs <CODE>file_source</CODE>, <CODE>file_sink</CODE>, <CODE>file</CODE>, <CODE>wfile_source</CODE>, <CODE>wfile_sink</CODE> and <CODE>wfile</CODE>.
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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/file.hpp'><CODE><boost/iostreams/device/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='file_source'>
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<H3>Class template <CODE>basic_file_source</CODE></H3>
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<H4>Description</H4>
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<P>
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<A HREF='http://www.boost.org/libs/utility/CopyConstructible.html'>CopyConstructible</A> and <A HREF='http://www.boost.org/libs/utility/Assignable.html'>Assignable</A> wrapper for a <CODE>std::basic_filebuf</CODE> opened in read-only mode.
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<P>
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<A NAME='file_source_synopsis'>
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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">template</SPAN><<SPAN CLASS="keyword">typename</SPAN> <A CLASS="documented" HREF="#basic_file_source_params">Ch</A>, <SPAN CLASS="keyword">typename</SPAN> <A CLASS="documented" HREF="#basic_file_source_params">Tr</A> = std::char_traits<Ch> >
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<SPAN CLASS="keyword">class</SPAN> <A CLASS="documented" HREF="#basic_file_source_params">basic_file_source</A> {
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<SPAN CLASS="keyword">public</SPAN>:
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<SPAN CLASS="keyword">typedef</SPAN> Ch char_type;
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<SPAN CLASS="keyword">typedef</SPAN> <SPAN CLASS='omitted'>implementation-defined</SPAN> io_category;
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<A CLASS="documented" HREF="#basic_file_source_constructor">basic_file_source</A>( <SPAN CLASS="keyword">const</SPAN> std::string& path,
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std::ios_base::openmode mode =
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std::ios_base::in );
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<SPAN CLASS='omitted'>...</SPAN>
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};
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<SPAN CLASS="keyword">typedef</SPAN> basic_file_source<<SPAN CLASS="keyword">char</SPAN>> <SPAN CLASS="defined">file_source</SPAN>;
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<SPAN CLASS="keyword">typedef</SPAN> basic_file_source<<SPAN CLASS="keyword">wchar_t</SPAN>> <SPAN CLASS="defined">wfile_source</SPAN>;
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} } // End namespace boost::io</PRE>
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<A NAME='basic_file_source_params'></A>
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<H4>Template parameters</H4>
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<TABLE STYLE='margin-left:2em'>
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<TR>
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<TD><I>Ch</I></TD><TD VALIGN='top'>-</TD>
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<TD>The character type.</TD></TR>
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<TR>
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<TD><I>Tr</I></TD><TD VALIGN='top'>-</TD>
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<TD>The traits type.</TD></TR>
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</TABLE>
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<A NAME='basic_file_source_constructor'></A>
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<H4><CODE>basic_file_source::basic_file_source</CODE></H4>
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<A NAME='basic_file_source_constructor'></A>
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<PRE CLASS='broken_ie'> basic_file_source( <SPAN CLASS="keyword">const</SPAN> std::string& path,
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std::ios_base::openmode mode );</PRE>
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<P>
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Constructs a <CODE>basic_file_source</CODE> which wraps a <CODE>std::basic_filebuf</CODE> <CODE>buf</CODE> opened as follows:
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<PRE CLASS='broken_ie'> mode |= std::ios_base::in;
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mode &= ~std::ios_base::out;
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buf.open(path.c_str(), mode);</PRE>
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</P>
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<A NAME='file_sink'>
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<H3>Class template <CODE>basic_file_sink</CODE></H3>
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<H4>Description</H4>
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<P>
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<A HREF='http://www.boost.org/libs/utility/CopyConstructible.html'>CopyConstructible</A> and <A HREF='http://www.boost.org/libs/utility/Assignable.html'>Assignable</A> wrapper for a <CODE>std::basic_filebuf</CODE> opened in write-only mode.
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<P>
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<A NAME='file_sink_synopsis'>
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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">template</SPAN><<SPAN CLASS="keyword">typename</SPAN> <A CLASS="documented" HREF="#basic_file_sink_params">Ch</A>, <SPAN CLASS="keyword">typename</SPAN> <A CLASS="documented" HREF="#basic_file_sink_params">Tr</A> = std::char_traits<Ch> >
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<SPAN CLASS="keyword">class</SPAN> <A CLASS="documented" HREF="#basic_file_sink_params">basic_file_sink</A> {
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<SPAN CLASS="keyword">public</SPAN>:
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<SPAN CLASS="keyword">typedef</SPAN> Ch char_type;
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<SPAN CLASS="keyword">typedef</SPAN> <SPAN CLASS='omitted'>implementation-defined</SPAN> io_category;
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<A CLASS="documented" HREF="#basic_file_sink_constructor">basic_file_sink</A>( <SPAN CLASS="keyword">const</SPAN> std::string& path,
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std::ios_base::openmode mode =
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std::ios_base::out );
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<SPAN CLASS='omitted'>...</SPAN>
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};
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<SPAN CLASS="keyword">typedef</SPAN> basic_file_sink<<SPAN CLASS="keyword">char</SPAN>> <SPAN CLASS="defined">file_sink</SPAN>;
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<SPAN CLASS="keyword">typedef</SPAN> basic_file_sink<<SPAN CLASS="keyword">wchar_t</SPAN>> <SPAN CLASS="defined">wfile_sink</SPAN>;
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} } // End namespace boost::io</PRE>
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<A NAME='basic_file_sink_params'></A>
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<H4>Template parameters</H4>
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<TABLE STYLE='margin-left:2em'>
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<TR>
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<TD><I>Ch</I></TD><TD VALIGN='top'>-</TD>
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<TD>The character type.</TD></TR>
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<TR>
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<TD><I>Tr</I></TD><TD VALIGN='top'>-</TD>
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<TD>The traits type.</TD></TR>
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</TABLE>
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<A NAME='basic_file_sink_constructor'></A>
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<H4><CODE>basic_file_sink::basic_file_sink</CODE></H4>
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<A NAME='basic_file_sink_constructor'></A>
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<PRE CLASS='broken_ie'> basic_file_sink( <SPAN CLASS="keyword">const</SPAN> std::string& path,
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std::ios_base::openmode mode );</PRE>
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<P>
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Constructs a <CODE>basic_file_sink</CODE> which wraps a <CODE>std::basic_filebuf</CODE> <CODE>buf</CODE> opened as follows:
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<PRE CLASS='broken_ie'> mode |= std::ios_base::out;
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mode &= ~std::ios_base::in;
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buf.open(path.c_str(), mode);</PRE>
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</P>
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<A NAME='file'>
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<H3>Class template <CODE>basic_file</CODE></H3>
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<H4>Description</H4>
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<P><A HREF='http://www.boost.org/libs/utility/CopyConstructible.html'>CopyConstructible</A> and <A HREF='http://www.boost.org/libs/utility/Assignable.html'>Assignable</A> wrapper for a <CODE>std::basic_filebuf</CODE> opened in read-write mode by default.
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<A NAME='file_synopsis'>
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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">template</SPAN><<SPAN CLASS="keyword">typename</SPAN> <A CLASS="documented" HREF="#basic_file_params">Ch</A>, <SPAN CLASS="keyword">typename</SPAN> <A CLASS="documented" HREF="#basic_file_params">Tr</A> = std::char_traits<Ch> >
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<SPAN CLASS="keyword">class</SPAN> <A CLASS="documented" HREF="#basic_file_params">basic_file</A> {
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<SPAN CLASS="keyword">public</SPAN>:
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<SPAN CLASS="keyword">typedef</SPAN> Ch char_type;
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<SPAN CLASS="keyword">typedef</SPAN> <SPAN CLASS='omitted'>implementation-defined</SPAN> io_category;
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<A CLASS="documented" HREF="#basic_file_constructor">basic_file</A>( <SPAN CLASS="keyword">const</SPAN> std::string& path,
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std::ios_base::openmode mode =
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std::ios_base::in | std::ios_base::out );
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<SPAN CLASS='omitted'>...</SPAN>
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};
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<SPAN CLASS="keyword">typedef</SPAN> basic_file<<SPAN CLASS="keyword">char</SPAN>> <SPAN CLASS="defined">file</SPAN>;
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<SPAN CLASS="keyword">typedef</SPAN> basic_file<<SPAN CLASS="keyword">wchar_t</SPAN>> <SPAN CLASS="defined">wfile</SPAN>;
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} } // End namespace boost::io</PRE>
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<A NAME='basic_file_params'></A>
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<H4>Template parameters</H4>
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<TABLE STYLE='margin-left:2em'>
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<TR>
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<TD><I>Ch</I></TD><TD VALIGN='top'>-</TD>
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<TD>The character type.</TD></TR>
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<TR>
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<TD><I>Tr</I></TD><TD VALIGN='top'>-</TD>
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<TD>The traits type.</TD></TR>
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</TABLE>
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<A NAME='basic_file_constructor'></A>
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<H4><CODE>basic_file_::basic_file</CODE></H4>
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<A NAME='basic_file_constructor'></A>
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<PRE CLASS='broken_ie'> basic_file( <SPAN CLASS="keyword">const</SPAN> std::string& path,
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std::ios_base::openmode mode );</PRE>
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<P>
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Constructs a <CODE>basic_file</CODE> which wraps a <CODE>std::basic_filebuf</CODE> <CODE>buf</CODE> opened as follows:
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<PRE CLASS='broken_ie'> mode |= std::ios_base::in | std::ios_base::out;
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buf.open(path.c_str(), mode);</PRE>
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</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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</BODY> |