ceph/src/boost/libs/iostreams/doc/functions/putback.html

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  12     <H1 CLASS="title">Function Template <CODE>putback</CODE></H1>
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  18   <DT><A href="#overview">Overview</A></DT>
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  20   <DT><A href="#reference">Reference</A></DT>
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  23 <A NAME="overview"></A>
  24 <H2>Overview</H2>
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  26 <P>
  27     The function template <CODE>putback</CODE> provides a uniform interface for putting back characters read from models of <A HREF="../concepts/peekable.html">Peekable</A>, for use in the definitions of <A HREF="../concepts/filter.html">Filters</A>.
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  34   <DT><A CLASS="header" HREF="../../../../boost/iostreams/operations.hpp"><CODE>&lt;boost/iostreams/operations.hpp&gt;</CODE></A></DT>
  35   <DT><A CLASS="header" HREF="../../../../boost/iostreams/putback.hpp"><CODE>&lt;boost/iostreams/putback.hpp&gt;</CODE></A></DT>
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  39 <H2>Reference</H2>
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  41 <A NAME="description"></A>
  42 <H4>Description</H4>
  43
  44 <P>Attempt to putback a character to a given instance of the template parameter <CODE>Peekable</CODE>, returning <CODE>true</CODE> for success.</P>
  45
  46 <A NAME="synopsis"></A>
  47 <H4>Synopsis</H4>
  48
  49 <PRE CLASS="broken_ie"><SPAN CLASS="keyword">namespace</SPAN> boost { <SPAN CLASS="keyword">namespace</SPAN> iostreams {
  50
  51     <SPAN CLASS="keyword">template</SPAN>&lt;<SPAN CLASS="keyword">typename</SPAN> <A CLASS="documented" HREF="#template_params">Peekable</A>&gt;
  52     <SPAN CLASS="keyword">bool</SPAN> <A CLASS="documented" HREF="#semantics">putback</A>(Peekable&amp; peekable, <SPAN CLASS="keyword">typename</SPAN> <A CLASS="documented" HREF="../guide/traits.html#char_type_of_ref">char_type_of</A>&lt;Peekable&gt;::type c);
  53
  54 } } <SPAN CLASS="comment">// End namespace boost::io</SPAN></PRE>
  55
  56 <A NAME="template_params"></A>
  57 <H4>Template Parameters</H4>
  58
  59 <TABLE STYLE="margin-left:2em" BORDER=0 CELLPADDING=2>
  60 <TR>
  61     <TR>
  62         <TD VALIGN="top"><I>Peekable</I></TD><TD WIDTH="2em" VALIGN="top">-</TD>
  63         <TD>A model of <A HREF="../concepts/peekable.html">Peekable</A>.
  64     </TR>
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  66
  67 <A NAME="semantics"></A>
  68 <H4>Semantics</H4>
  69
  70 <P>The semantics of <CODE>putback</CODE> depends on the <A HREF="../guide/traits.html#category">category</A> of <CODE>Peekable</CODE> as follows:</P>
  71
  72 <TABLE STYLE="margin:0,0,2em,2em" BORDER=1 CELLPADDING=4>
  73     <TR><TH><CODE>category_of&lt;Peekable&gt;::type</CODE></TH><TH>semantics</TH></TR>
  74     <TR>
  75         <TD VALIGN="top">convertible to <A HREF="../guide/traits.html#category_tags"><CODE>istream_tag</CODE></A></TD>
  76         <TD>invokes <CODE>peekable.rdbuf()->putback(c)</CODE> and returns <CODE>true</CODE> if the operation was successful</CODE></TD>
  77     </TR>
  78     <TR>
  79         <TD VALIGN="top">convertible to <A HREF="../guide/traits.html#category_tags"><CODE>streambuf_tag</CODE></A> but not to <A HREF="../guide/traits.html#category_tags"><CODE>istream_tag</CODE></A></TD>
  80         <TD>invokes <CODE>peekable.sputbackc(c)</CODE> and returns <CODE>true</CODE> if the operation was successful</TD>
  81     </TR>
  82     <TR>
  83         <TD VALIGN="top">convertible to <A HREF="../guide/traits.html#category_tags"><CODE>peekable_tag</CODE></A> but not to <A HREF="../guide/traits.html#category_tags"><CODE>streambuf_tag</CODE></A> or <A HREF="../guide/traits.html#category_tags"><CODE>istream_tag</CODE></A></TD>
  84         <TD>returns <CODE>peekable.putback(c)</CODE></TD>
  85     </TR>
  86     <TR>
  87         <TD VALIGN="top">otherwise</TD>
  88         <TD>compile-time error</CODE></TD>
  89     </TR>
  90 </TABLE>
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  96 <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>
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  98     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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