| <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> |
| <HTML> |
| <HEAD> |
| <TITLE>Class Template chain</TITLE> |
| <LINK REL="stylesheet" HREF="../../../../boost.css"> |
| <LINK REL="stylesheet" HREF="../theme/iostreams.css"> |
| </HEAD> |
| <BODY> |
| |
| <!-- Begin Banner --> |
| |
| <H1 CLASS="title">Class Template <CODE>char_traits</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 template <CODE>boost::iostreams::char_traits</CODE> is a derived class of <CODE>std::char_traits</CODE> which has an additional static function <A HREF='#would_block_function'><CODE>would_block</CODE></A>, used to indicate that an attempt to read a character has failed because no input is currently available. |
| </P> |
| |
| <P> |
| The constants <CODE>WOULD_BLOCK</CODE> and <CODE>WWOULD_BLOCK</CODE> are provided for convenience. |
| </P> |
| |
| <A NAME="headers"></A> |
| <H2>Headers</H2> |
| |
| <DL class="page-index"> |
| <DT><A CLASS="header" HREF="../../../../boost/iostreams/char_traits.hpp"><CODE><boost/iostreams/char_traits.hpp></CODE></A></DT> |
| </DL> |
| |
| <A NAME="reference"></A> |
| <H2>Reference</H2> |
| |
| <A NAME="synopsis"></A> |
| <H3>Synopsis</H3> |
| |
| <PRE CLASS="broken_ie"><SPAN CLASS="keyword">namespace</SPAN> boost { <SPAN CLASS="keyword">namespace</SPAN> iostreams { |
| |
| <SPAN CLASS="keyword">const</SPAN> <SPAN CLASS="keyword">int</SPAN> <A CLASS="documented" HREF="#WOULD_BLOCK">WOULD_BLOCK</A>; |
| |
| <SPAN CLASS="keyword">const</SPAN> std::wint_t <A CLASS="documented" HREF="#WWOULD_BLOCK">WWOULD_BLOCK</A>; |
| |
| <SPAN CLASS="keyword">template</SPAN><<SPAN CLASS="keyword">typename</SPAN> <A CLASS="documented" HREF="#template_params">Ch</A>> |
| <SPAN CLASS="keyword">class</SPAN> <A CLASS="documented" HREF="#template_params">char_traits</A> : public std::char_traits<Ch> { |
| <SPAN CLASS='keyword'>static</SPAN> <SPAN CLASS='keyword'>typename</SPAN> std::char_traits<Ch>::int_type <A CLASS='documented' HREF='#would_block_function'>would_block</A>(); |
| }; |
| |
| } } // End namespace boost::io</PRE> |
| |
| <A NAME="WOULD_BLOCK"></A> |
| <H3>Constant <CODE>WOULD_BLOCK</CODE></H3> |
| |
| <PRE CLASS="broken_ie"> <SPAN CLASS="keyword">const</SPAN> <SPAN CLASS="keyword">int</SPAN> WOULD_BLOCK;</PRE> |
| |
| <P>The return value of <CODE>char_traits<char>::would_block</CODE>. Used by the function template <A HREF="../functions/get.html"><CODE>get</CODE></A> to indicate that no character could be returned because input was temporarily unavailable.</P> |
| |
| <A NAME="WWOULD_BLOCK"></A> |
| <H3>Constant <CODE>WWOULD_BLOCK</CODE></H3> |
| |
| <PRE CLASS="broken_ie"> <SPAN CLASS="keyword">const</SPAN> std::wint_t WWOULD_BLOCK;</PRE> |
| |
| <P>The return value of <CODE>char_traits<wchar_t>::would_block</CODE>. Used by the function template <A HREF="../functions/get.html"><CODE>get</CODE></A> to indicate that no character could be returned because input was temporarily unavailable.</P> |
| |
| <A NAME="char_traits"></A> |
| <H3>Class Template <CODE>boost::iostreams::char_traits</CODE></H3> |
| |
| <A NAME="template_params"></A> |
| <H4>Template parameters</H4> |
| |
| <TABLE STYLE="margin-left:2em" BORDER=0 CELLPADDING=2> |
| <TR> |
| <TD VALIGN="top"><I>Ch</I></TD><TD WIDTH="2em" VALIGN="top">-</TD> |
| <TD>The character type</TD> |
| </TR> |
| </TABLE> |
| |
| <A NAME="would_block_function"></A> |
| <H4><CODE>char_traits::would_block</CODE></H4> |
| |
| <PRE CLASS="broken_ie"> <SPAN CLASS='keyword'>static</SPAN> <SPAN CLASS='keyword'>typename</SPAN> std::char_traits<Ch>::int_type would_block();</PRE> |
| |
| <P> |
| Returns an instance of <CODE>int_type</CODE> used by the function template <A HREF='../functions/get.html'><CODE>get</CODE></A> to indicate that an attempt to read a character from a <A HREF='../concepts/source.html'>Source</A> has failed because no input is currently available. Future attempts to read a character may succeed. |
| </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> |
| |
| <!-- End Footer --> |
| |
| </BODY> |
