char_traits.html 4.4 KB

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  10. <H1 CLASS="title">Class Template <CODE>char_traits</CODE></H1>
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  14. <DT><A href="#description">Description</A></DT>
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  20. <H2>Description</H2>
  21. <P>
  22. 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.
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  25. The constants <CODE>WOULD_BLOCK</CODE> and <CODE>WWOULD_BLOCK</CODE> are provided for convenience.
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  30. <DT><A CLASS="header" HREF="../../../../boost/iostreams/char_traits.hpp"><CODE>&lt;boost/iostreams/char_traits.hpp&gt;</CODE></A></DT>
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  33. <H2>Reference</H2>
  34. <A NAME="synopsis"></A>
  35. <H3>Synopsis</H3>
  36. <PRE CLASS="broken_ie"><SPAN CLASS="keyword">namespace</SPAN> boost { <SPAN CLASS="keyword">namespace</SPAN> iostreams {
  37. <SPAN CLASS="keyword">const</SPAN> <SPAN CLASS="keyword">int</SPAN> <A CLASS="documented" HREF="#WOULD_BLOCK">WOULD_BLOCK</A>;
  38. <SPAN CLASS="keyword">const</SPAN> std::wint_t <A CLASS="documented" HREF="#WWOULD_BLOCK">WWOULD_BLOCK</A>;
  39. <SPAN CLASS="keyword">template</SPAN>&lt;<SPAN CLASS="keyword">typename</SPAN> <A CLASS="documented" HREF="#template_params">Ch</A>&gt;
  40. <SPAN CLASS="keyword">class</SPAN> <A CLASS="documented" HREF="#template_params">char_traits</A> : public std::char_traits&lt;Ch&gt; {
  41. <SPAN CLASS='keyword'>static</SPAN> <SPAN CLASS='keyword'>typename</SPAN> std::char_traits&lt;Ch&gt;::int_type <A CLASS='documented' HREF='#would_block_function'>would_block</A>();
  42. };
  43. } } // End namespace boost::io</PRE>
  44. <A NAME="WOULD_BLOCK"></A>
  45. <H3>Constant <CODE>WOULD_BLOCK</CODE></H3>
  46. <PRE CLASS="broken_ie"> <SPAN CLASS="keyword">const</SPAN> <SPAN CLASS="keyword">int</SPAN> WOULD_BLOCK;</PRE>
  47. <P>The return value of <CODE>char_traits&lt;char&gt;::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>
  48. <A NAME="WWOULD_BLOCK"></A>
  49. <H3>Constant <CODE>WWOULD_BLOCK</CODE></H3>
  50. <PRE CLASS="broken_ie"> <SPAN CLASS="keyword">const</SPAN> std::wint_t WWOULD_BLOCK;</PRE>
  51. <P>The return value of <CODE>char_traits&lt;wchar_t&gt;::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>
  52. <A NAME="char_traits"></A>
  53. <H3>Class Template <CODE>boost::iostreams::char_traits</CODE></H3>
  54. <A NAME="template_params"></A>
  55. <H4>Template parameters</H4>
  56. <TABLE STYLE="margin-left:2em" BORDER=0 CELLPADDING=2>
  57. <TR>
  58. <TD VALIGN="top"><I>Ch</I></TD><TD WIDTH="2em" VALIGN="top">-</TD>
  59. <TD>The character type</TD>
  60. </TR>
  61. </TABLE>
  62. <A NAME="would_block_function"></A>
  63. <H4><CODE>char_traits::would_block</CODE></H4>
  64. <PRE CLASS="broken_ie"> <SPAN CLASS='keyword'>static</SPAN> <SPAN CLASS='keyword'>typename</SPAN> std::char_traits&lt;Ch&gt;::int_type would_block();</PRE>
  65. <P>
  66. 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.
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  70. <P CLASS="copyright">&copy; Copyright 2008 <a href="http://www.coderage.com/" target="_top">CodeRage, LLC</a><br/>&copy; Copyright 2004-2007 <a href="https://www.boost.org/users/people/jonathan_turkanis.html" target="_top">Jonathan Turkanis</a></P>
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  72. 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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