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     <H1 CLASS="title">Class Template <CODE>code_converter</CODE></H1>
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 <DL class="page-index">
   <DT><A href="#description">Description</A></DT>
   <DT><A href="#headers">Headers</A></DT>
   <DT><A href="#reference">Reference</A></DT>
 </DL>

 <HR>

 <A NAME="description"></A>
 <H2>Description</H2>

 <P>
     The class templates <CODE>code_converter</CODE> is a <SPAN CLASS="term">Device adapter</SPAN> which takes a Device with a narrow <A HREF="../guide/traits.html#char_type">character type</A>  typically <CODE>char</CODE>  and produces a Device with wide character type  typically <CODE>wchar_t</CODE>  by introducing a layer of <A HREF="../guide/code_conversion.html">code conversion</A>. The code conversion is performed using a <CODE>std::codecvt</CODE> facet which can either be specified as a template parameter or be fetched from a <CODE>std::locale</CODE> provided at runtime.
 </P>
 <P>
     For example, we can define a wide-character Device for reading from a memory-mapped file as follows:
     <PRE CLASS="broken_ie">    <SPAN CLASS="preprocessor">#include</SPAN> <A CLASS="header" HREF="../../../../boost/iostreams/device/mapped_file.hpp"><SPAN CLASS="literal">&lt;boost/iostreams/maped_file.hpp&gt;</SPAN></A>

     <SPAN CLASS="keyword">typedef</SPAN> code_converter&lt;mapped_file_source&gt; my_source;</PRE>

     Similarly, we can define a wide-character Device which writes multibyte characters to an in-memory character sequence as follows:

     <PRE CLASS="broken_ie">    <SPAN CLASS="preprocessor">#include</SPAN> <A CLASS="header" HREF="../../../../boost/iostreams/device/array.hpp"><SPAN CLASS="literal">&lt;boost/iostreams/device/array.hpp&gt;</SPAN></A>

     <SPAN CLASS="keyword">typedef</SPAN> code_converter&lt;array_sink&gt; my_sink;</PRE>
 </P>
 <P>
     The <A HREF="../guide/modes.html">mode</A> of a specialization of <CODE>code_converter</CODE> is determined as follows. If a narrow character Device is read-only, the resulting specialization of <CODE>code_converter</CODE> has mode <A HREF="../guide/modes.html#input">input</A>. If a narrow character Device is write-only, the resulting specialization of <CODE>code_converter</CODE> has mode <A HREF="../guide/modes.html#output">output</A>. If a narrow character Device performs input and output using two distinct sequences (<I>see</I> <A HREF="../guide/modes.html">Modes</A>), the resulting specialization of <CODE>code_converter</CODE> has mode <A HREF="../guide/modes.html#bidirectional">bidirectional</A>. Otherwise, attempting to spcialize <CODE>code_converter</CODE> results in a compile-time error.
 </P>

 <A NAME="headers"></A>
 <H2>Headers</H2>

 <DL class="page-index">
   <DT><A CLASS="header" HREF="../../../../boost/iostreams/code_converter.hpp"><CODE>&lt;boost/iostreams/code_converter.hpp&gt;</CODE></A></DT>
 </DL>

 <A NAME="reference"></A>
 <H2>Reference</H2>

 <H4>Synopsis</H4>

 <PRE CLASS="broken_ie"><SPAN CLASS="keyword">namespace</SPAN> boost { <SPAN CLASS="keyword">namespace</SPAN> iostreams {

 <SPAN CLASS="keyword">template</SPAN>&lt; <SPAN CLASS="keyword">typename</SPAN> <A CLASS="documented" HREF="#template_params">Device</A>,
           <SPAN CLASS="keyword">typename</SPAN> <A CLASS="documented" HREF="#template_params">Codecvt</A> = <SPAN CLASS='omitted'>default_value</SPAN>
           <SPAN CLASS="keyword">typename</SPAN> <A CLASS="documented" HREF="#template_params">Alloc</A> = std::allocator&lt;<CODE>char</CODE>&gt; &gt;
 <SPAN CLASS="keyword">class</SPAN> <A CLASS="documented" HREF="#template_params">code_converter</A> {
 <SPAN CLASS="keyword">public</SPAN>:
     <SPAN CLASS="keyword">typedef</SPAN> <SPAN CLASS="keyword">typename</SPAN> Codecvt::intern_type  char_type;
     <SPAN CLASS="keyword">typedef</SPAN> <SPAN CLASS="omitted">implementation-defined</SPAN>         category;
     <A CLASS="documented" HREF="#constructors">code_converter</A>();
     <A CLASS="documented" HREF="#constructors">code_converter</A>( <SPAN CLASS="keyword">const</SPAN> Device& dev,
                     std::streamsize buffer_size = <SPAN CLASS="omitted">default_value</SPAN> );
     <SPAN CLASS="keyword">void</SPAN> <A CLASS="documented" HREF="#open">open</A>( <SPAN CLASS="keyword">const</SPAN> Device& dev,
                std::streamsize buffer_size = <SPAN CLASS="omitted">default_value</SPAN> );
     <SPAN CLASS="keyword">bool</SPAN> <A CLASS="documented" HREF="#is_open">is_open</A>() <SPAN CLASS="keyword">const</SPAN>;
     <SPAN CLASS="keyword">void</SPAN> <A CLASS="documented" HREF="#close">close</A>();
     std::locale <A CLASS="documented" HREF="#imbue">imbue</A>(<SPAN CLASS="keyword">const</SPAN> std::locale& loc);
     Device& <A CLASS="documented" HREF="#operator_star">operator*</A>();
     Device* <A CLASS="documented" HREF="#operator_arrow">operator-&gt;</A>();
 };

 } } <SPAN CLASS="comment">// End namespace boost::io</SPAN></PRE>

 <A NAME="template_params"></A>
 <H4>Template parameters</H4>

 <TABLE STYLE="margin-left:2em" BORDER=0 CELLPADDING=2>
 <TR>
     <TR>
         <TD VALIGN="top"><I>Device</I></TD><TD WIDTH="2em" VALIGN="top">-</TD>
         <TD>A model of one of the <A HREF="../guide/concepts.html#device_concepts">Device</A> concepts; typically has <A HREF="../guide/traits.html#char_type">character type</A> <CODE>char</CODE>.</TD>
     </TR>
     <TR>
         <TD VALIGN="top"><I>Codecvt</I></TD><TD WIDTH="2em" VALIGN="top">-</TD>
         <TD>
             A standard library codecvt facet, which must be default constructible. If this parameter is not specified,
             an instance of <CODE>std::codecvt&lt;wchar_t, char, std::mbstate_t&gt;</CODE> will be fetched from the global
             local when a <CODE>code_converter</CODE> is constructed or opened.
         </TD>
     </TR>
     <TR>
         <TD VALIGN="top"><I>Alloc</I></TD><TD WIDTH="2em" VALIGN="top">-</TD>
         <TD>A standard library allocator type (<A CLASS="bib_ref" HREF="../bibliography.html#iso">[ISO]</A>, 20.1.5), used to allocate character buffers</TD>
     </TR>
 </TABLE>

 <A NAME="constructors"></A>
 <H4><CODE>code_converter::code_converter</CODE></H4>

 <PRE CLASS="broken_ie">    code_converter();
     code_converter( <SPAN CLASS="keyword">const</SPAN> Device& dev,
                     std::streamsize buffer_size );</PRE>

 <P>
     The first member constructs a <CODE>code_converter</CODE> with no associated instance of the Device type <CODE>Device</CODE>. Before the instance can be used for i/o, the member function <CODE>open()</CODE> must be invoked.
 </P>

 <P>
     The second member constructs a <CODE>code_converter</CODE> based on the given instance of <CODE>Device</CODE>. The second parameter determines the size of the buffers or buffers used for code conversion. If a <CODE>std::codecvt</CODE> was specified as a template parameter, an instance of it will be default constructed. Otherwise, a copy of the global <CODE>locale</CODE> will be made, and an instance of <CODE>std::codecvt&lt;wchar_t, char, std::mbstate_t&gt;</CODE> will be fetched from it.
 </P>

 <A NAME="imbue"></A>
 <H4><CODE>code_converter::imbue</CODE></H4>

 <PRE CLASS="broken_ie">    std::locale imbue(<SPAN CLASS="keyword">const</SPAN> std::locale& loc);</PRE>

 <P>
     Used to specify a locale from which a <CODE>std::codecvt</CODE> facet will be fetched to perform code conversion. The effect of invoking imbue while code conversion is in progress is undefined.
 </P>

 <P>
     This function is a no-op if a <CODE>std::codecvt</CODE> facet was specified as a template parameter.
 </P>

 <A NAME="open"></A>
 <H4><CODE>code_converter::open</CODE></H4>

 <PRE CLASS="broken_ie">     <SPAN CLASS="keyword">void</SPAN> open( <SPAN CLASS="keyword">const</SPAN> Device& dev,
                 std::streamsize buffer_size = <SPAN CLASS="omitted">default_value</SPAN> );</PRE>

 <P>
     Assocaites the given instance of <CODE>Device</CODE> with <CODE>this</CODE> instance of <CODE>code_converter</CODE>, if there is no such instance currently associated; otherwise, throws <CODE>std::ios_base::failure</CODE>. The second parameter determines the size of the buffer or buffers used for code conversion. If a <CODE>std::codecvt</CODE> was specified as a template parameter, an instance of it will be default constructed. Otherwise, a copy of the global <CODE>locale</CODE> will be made, and an instance of <CODE>std::codecvt&lt;wchar_t, char, std::mbstate_t&gt;</CODE> will be fetched from it.
 </P>

 <A NAME="is_open"></A>
 <H4><CODE>code_converter::is_open</CODE></H4>

 <PRE CLASS="broken_ie">    <SPAN CLASS="keyword">bool</SPAN> is_open() <SPAN CLASS="keyword">const</SPAN>;</PRE>

 <P>Returns true if there is an instance of the Device type <CODE>Device</CODE> associated with <CODE>this</CODE> instance of <CODE>code_converter</CODE>.</P>

 <A NAME="close"></A>
 <H4><CODE>code_converter::close</CODE></H4>

 <PRE CLASS="broken_ie">    <SPAN CLASS="keyword">void</SPAN> close();</PRE>

 <P>
     Disassociates from <CODE>this</CODE> instance of <CODE>code_converter</CODE> any instance of the Device type <CODE>Device</CODE> currently associated with it, calling cleanup functions as appropriate and destroying the associated instance of <CODE>Device</CODE>.
 </P>

 <A NAME="operator_star"></A>
 <H4><CODE>code_converter::operator*</CODE></H4>

 <PRE CLASS="broken_ie">    Device& operator*();</PRE>

 <P>
      Returns a reference to the instance of Device associated with this instance of <CODE>code_converter</CODE>, which must be <A HREF="#is_open">open</A>.
 </P>

 <A NAME="operator_arrow"></A>
 <H4><CODE>code_converter::operator-></CODE></H4>

 <PRE CLASS="broken_ie">    Device* operator->();</PRE>

 <P>
     Returns a pointer to the instance of Device associated with this instance of <CODE>code_converter</CODE>, which must be <A HREF="#is_open">open</A>.
 </P>

 <!-- Begin Footer -->

 <HR>
 <P CLASS="copyright">Revised 02 Feb 2008</P>

 <P CLASS="copyright">&copy; Copyright 2008 <a href="http://www.coderage.com/" target="_top">CodeRage, LLC</a><br/>&copy; Copyright 2004-2007 <a href="http://www.coderage.com/turkanis/" target="_top">Jonathan Turkanis</a></P>
 <P CLASS="copyright">
     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>)
 </P>

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	<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
	<HTML>
	<HEAD>
	<TITLE>Class Template code_converter</TITLE>
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	<!-- Begin Banner -->

	<H1 CLASS="title">Class Template <CODE>code_converter</CODE></H1>
	<HR CLASS="banner">

	<!-- End Banner -->

	<DL class="page-index">
	<DT><A href="#description">Description</A></DT>
	<DT><A href="#headers">Headers</A></DT>
	<DT><A href="#reference">Reference</A></DT>
	</DL>

	<HR>

	<A NAME="description"></A>
	<H2>Description</H2>

	<P>
	The class templates <CODE>code_converter</CODE> is a <SPAN CLASS="term">Device adapter</SPAN> which takes a Device with a narrow <A HREF="../guide/traits.html#char_type">character type</A> typically <CODE>char</CODE> and produces a Device with wide character type typically <CODE>wchar_t</CODE> by introducing a layer of <A HREF="../guide/code_conversion.html">code conversion</A>. The code conversion is performed using a <CODE>std::codecvt</CODE> facet which can either be specified as a template parameter or be fetched from a <CODE>std::locale</CODE> provided at runtime.
	</P>
	<P>
	For example, we can define a wide-character Device for reading from a memory-mapped file as follows:
	<PRE CLASS="broken_ie"> <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>

	<SPAN CLASS="keyword">typedef</SPAN> code_converter<mapped_file_source> my_source;</PRE>

	Similarly, we can define a wide-character Device which writes multibyte characters to an in-memory character sequence as follows:

	<PRE CLASS="broken_ie"> <SPAN CLASS="preprocessor">#include</SPAN> <A CLASS="header" HREF="../../../../boost/iostreams/device/array.hpp"><SPAN CLASS="literal"><boost/iostreams/device/array.hpp></SPAN></A>

	<SPAN CLASS="keyword">typedef</SPAN> code_converter<array_sink> my_sink;</PRE>
	</P>
	<P>
	The <A HREF="../guide/modes.html">mode</A> of a specialization of <CODE>code_converter</CODE> is determined as follows. If a narrow character Device is read-only, the resulting specialization of <CODE>code_converter</CODE> has mode <A HREF="../guide/modes.html#input">input</A>. If a narrow character Device is write-only, the resulting specialization of <CODE>code_converter</CODE> has mode <A HREF="../guide/modes.html#output">output</A>. If a narrow character Device performs input and output using two distinct sequences (<I>see</I> <A HREF="../guide/modes.html">Modes</A>), the resulting specialization of <CODE>code_converter</CODE> has mode <A HREF="../guide/modes.html#bidirectional">bidirectional</A>. Otherwise, attempting to spcialize <CODE>code_converter</CODE> results in a compile-time error.
	</P>

	<A NAME="headers"></A>
	<H2>Headers</H2>

	<DL class="page-index">
	<DT><A CLASS="header" HREF="../../../../boost/iostreams/code_converter.hpp"><CODE><boost/iostreams/code_converter.hpp></CODE></A></DT>
	</DL>

	<A NAME="reference"></A>
	<H2>Reference</H2>

	<H4>Synopsis</H4>

	<PRE CLASS="broken_ie"><SPAN CLASS="keyword">namespace</SPAN> boost { <SPAN CLASS="keyword">namespace</SPAN> iostreams {

	<SPAN CLASS="keyword">template</SPAN>< <SPAN CLASS="keyword">typename</SPAN> <A CLASS="documented" HREF="#template_params">Device</A>,
	<SPAN CLASS="keyword">typename</SPAN> <A CLASS="documented" HREF="#template_params">Codecvt</A> = <SPAN CLASS='omitted'>default_value</SPAN>
	<SPAN CLASS="keyword">typename</SPAN> <A CLASS="documented" HREF="#template_params">Alloc</A> = std::allocator<<CODE>char</CODE>> >
	<SPAN CLASS="keyword">class</SPAN> <A CLASS="documented" HREF="#template_params">code_converter</A> {
	<SPAN CLASS="keyword">public</SPAN>:
	<SPAN CLASS="keyword">typedef</SPAN> <SPAN CLASS="keyword">typename</SPAN> Codecvt::intern_type char_type;
	<SPAN CLASS="keyword">typedef</SPAN> <SPAN CLASS="omitted">implementation-defined</SPAN> category;
	<A CLASS="documented" HREF="#constructors">code_converter</A>();
	<A CLASS="documented" HREF="#constructors">code_converter</A>( <SPAN CLASS="keyword">const</SPAN> Device& dev,
	std::streamsize buffer_size = <SPAN CLASS="omitted">default_value</SPAN> );
	<SPAN CLASS="keyword">void</SPAN> <A CLASS="documented" HREF="#open">open</A>( <SPAN CLASS="keyword">const</SPAN> Device& dev,
	std::streamsize buffer_size = <SPAN CLASS="omitted">default_value</SPAN> );
	<SPAN CLASS="keyword">bool</SPAN> <A CLASS="documented" HREF="#is_open">is_open</A>() <SPAN CLASS="keyword">const</SPAN>;
	<SPAN CLASS="keyword">void</SPAN> <A CLASS="documented" HREF="#close">close</A>();
	std::locale <A CLASS="documented" HREF="#imbue">imbue</A>(<SPAN CLASS="keyword">const</SPAN> std::locale& loc);
	Device& <A CLASS="documented" HREF="#operator_star">operator*</A>();
	Device* <A CLASS="documented" HREF="#operator_arrow">operator-></A>();
	};

	} } <SPAN CLASS="comment">// End namespace boost::io</SPAN></PRE>

	<A NAME="template_params"></A>
	<H4>Template parameters</H4>

	<TABLE STYLE="margin-left:2em" BORDER=0 CELLPADDING=2>
	<TR>
	<TR>
	<TD VALIGN="top"><I>Device</I></TD><TD WIDTH="2em" VALIGN="top">-</TD>
	<TD>A model of one of the <A HREF="../guide/concepts.html#device_concepts">Device</A> concepts; typically has <A HREF="../guide/traits.html#char_type">character type</A> <CODE>char</CODE>.</TD>
	</TR>
	<TR>
	<TD VALIGN="top"><I>Codecvt</I></TD><TD WIDTH="2em" VALIGN="top">-</TD>
	<TD>
	A standard library codecvt facet, which must be default constructible. If this parameter is not specified,
	an instance of <CODE>std::codecvt<wchar_t, char, std::mbstate_t></CODE> will be fetched from the global
	local when a <CODE>code_converter</CODE> is constructed or opened.
	</TD>
	</TR>
	<TR>
	<TD VALIGN="top"><I>Alloc</I></TD><TD WIDTH="2em" VALIGN="top">-</TD>
	<TD>A standard library allocator type (<A CLASS="bib_ref" HREF="../bibliography.html#iso">[ISO]</A>, 20.1.5), used to allocate character buffers</TD>
	</TR>
	</TABLE>

	<A NAME="constructors"></A>
	<H4><CODE>code_converter::code_converter</CODE></H4>

	<PRE CLASS="broken_ie"> code_converter();
	code_converter( <SPAN CLASS="keyword">const</SPAN> Device& dev,
	std::streamsize buffer_size );</PRE>

	<P>
	The first member constructs a <CODE>code_converter</CODE> with no associated instance of the Device type <CODE>Device</CODE>. Before the instance can be used for i/o, the member function <CODE>open()</CODE> must be invoked.
	</P>

	<P>
	The second member constructs a <CODE>code_converter</CODE> based on the given instance of <CODE>Device</CODE>. The second parameter determines the size of the buffers or buffers used for code conversion. If a <CODE>std::codecvt</CODE> was specified as a template parameter, an instance of it will be default constructed. Otherwise, a copy of the global <CODE>locale</CODE> will be made, and an instance of <CODE>std::codecvt<wchar_t, char, std::mbstate_t></CODE> will be fetched from it.
	</P>

	<A NAME="imbue"></A>
	<H4><CODE>code_converter::imbue</CODE></H4>

	<PRE CLASS="broken_ie"> std::locale imbue(<SPAN CLASS="keyword">const</SPAN> std::locale& loc);</PRE>

	<P>
	Used to specify a locale from which a <CODE>std::codecvt</CODE> facet will be fetched to perform code conversion. The effect of invoking imbue while code conversion is in progress is undefined.
	</P>

	<P>
	This function is a no-op if a <CODE>std::codecvt</CODE> facet was specified as a template parameter.
	</P>

	<A NAME="open"></A>
	<H4><CODE>code_converter::open</CODE></H4>

	<PRE CLASS="broken_ie"> <SPAN CLASS="keyword">void</SPAN> open( <SPAN CLASS="keyword">const</SPAN> Device& dev,
	std::streamsize buffer_size = <SPAN CLASS="omitted">default_value</SPAN> );</PRE>

	<P>
	Assocaites the given instance of <CODE>Device</CODE> with <CODE>this</CODE> instance of <CODE>code_converter</CODE>, if there is no such instance currently associated; otherwise, throws <CODE>std::ios_base::failure</CODE>. The second parameter determines the size of the buffer or buffers used for code conversion. If a <CODE>std::codecvt</CODE> was specified as a template parameter, an instance of it will be default constructed. Otherwise, a copy of the global <CODE>locale</CODE> will be made, and an instance of <CODE>std::codecvt<wchar_t, char, std::mbstate_t></CODE> will be fetched from it.
	</P>

	<A NAME="is_open"></A>
	<H4><CODE>code_converter::is_open</CODE></H4>

	<PRE CLASS="broken_ie"> <SPAN CLASS="keyword">bool</SPAN> is_open() <SPAN CLASS="keyword">const</SPAN>;</PRE>

	<P>Returns true if there is an instance of the Device type <CODE>Device</CODE> associated with <CODE>this</CODE> instance of <CODE>code_converter</CODE>.</P>

	<A NAME="close"></A>
	<H4><CODE>code_converter::close</CODE></H4>

	<PRE CLASS="broken_ie"> <SPAN CLASS="keyword">void</SPAN> close();</PRE>

	<P>
	Disassociates from <CODE>this</CODE> instance of <CODE>code_converter</CODE> any instance of the Device type <CODE>Device</CODE> currently associated with it, calling cleanup functions as appropriate and destroying the associated instance of <CODE>Device</CODE>.
	</P>

	<A NAME="operator_star"></A>
	<H4><CODE>code_converter::operator*</CODE></H4>

	<PRE CLASS="broken_ie"> Device& operator*();</PRE>

	<P>
	Returns a reference to the instance of Device associated with this instance of <CODE>code_converter</CODE>, which must be <A HREF="#is_open">open</A>.
	</P>

	<A NAME="operator_arrow"></A>
	<H4><CODE>code_converter::operator-></CODE></H4>

	<PRE CLASS="broken_ie"> Device* operator->();</PRE>

	<P>
	Returns a pointer to the instance of Device associated with this instance of <CODE>code_converter</CODE>, which must be <A HREF="#is_open">open</A>.
	</P>

	<!-- Begin Footer -->

	<HR>
	<P CLASS="copyright">Revised 02 Feb 2008</P>

	<P CLASS="copyright">© Copyright 2008 <a href="http://www.coderage.com/" target="_top">CodeRage, LLC</a><br/>© Copyright 2004-2007 <a href="http://www.coderage.com/turkanis/" target="_top">Jonathan Turkanis</a></P>
	<P CLASS="copyright">
	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>)
	</P>

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