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

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  12     <H1 CLASS="title">Function Template <CODE>optimal_buffer_size</CODE></H1>
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  24 <H2>Overview</H2>
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  26 <P>
  27     The function template <CODE>optimal_buffer_size</CODE> returns the size of the character buffer which is allocated for a Filter or Device by library streams, stream buffers and chains if no buffer size is explicitly specified.
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  34   <DT><A CLASS="header" HREF="../../../../boost/iostreams/optimal_buffer_size.hpp"><CODE>&lt;boost/iostreams/optimal_buffer_size.hpp&gt;</CODE></A></DT>
  35   <DT><A CLASS="header" HREF="../../../../boost/iostreams/operations.hpp"><CODE>&lt;boost/iostreams/operations.hpp&gt;</CODE></A></DT>
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  39 <H2>Reference</H2>
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  41 <A NAME="synopsis"></A>
  42 <H4>Synopsis</H4>
  43
  44 <PRE CLASS="broken_ie"><SPAN CLASS="keyword">namespace</SPAN> boost { <SPAN CLASS="keyword">namespace</SPAN> iostreams {
  45
  46 <SPAN CLASS="keyword">template</SPAN>&lt;<SPAN CLASS="keyword">typename</SPAN> <A CLASS="documented" HREF="#template_params">T</A>&gt;
  47 std::streamsize <A CLASS="documented" HREF="#optimal_buffer_size">optimal_buffer_size</A>(T&amp; t);
  48
  49 } } <SPAN CLASS="comment">// End namespace boost::io</SPAN></PRE>
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  51 <A NAME="template_params"></A>
  52 <H4>Template Parameters</H4>
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  54 <TABLE STYLE="margin-left:2em" BORDER=0 CELLPADDING=2>
  55 <TR>
  56     <TR>
  57         <TD VALIGN="top"><I>T</I></TD><TD WIDTH="2em" VALIGN="top">-</TD>
  58         <TD>A model of <A HREF="../concepts/filter.html">Filter</A> or <A HREF="../concepts/device.html">Device</A>.
  59     </TR>
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  62 <A NAME="optimal_buffer_size"></A>
  63 <PRE CLASS="broken_ie"><SPAN CLASS="keyword">template</SPAN>&lt;<SPAN CLASS="keyword">typename</SPAN> T&gt;
  64 std::streamsize optimal_buffer_size(T&amp; t);</PRE>
  65
  66 <P>The semantics of <CODE>optimal_buffer_size</CODE> depends on the <A HREF="../guide/traits.html#category">category</A> of <CODE>T</CODE> as follows:</P>
  67
  68 <TABLE STYLE="margin-left:2em;margin-bottom:2em" BORDER=1 CELLPADDING=4>
  69     <TR><TH><CODE>category_of&lt;T&gt;::type</CODE></TH><TH>semantics</TH></TR>
  70     <TR>
  71         <TD VALIGN="top">convertible to <A HREF="../guide/traits.html#category_tags"><CODE>optimally_buffered_tag</CODE></A></TD>
  72         <TD>Returns <CODE>t.optimal_buffer_size()</CODE>.</TD>
  73     </TR>
  74     <TR>
  75         <TD VALIGN="top">convertible to <A HREF="../guide/traits.html#category_tags"><CODE>filter_tag</CODE></A> but not to <A HREF="../guide/traits.html#category_tags"><CODE>optimally_buffered_tag</CODE></A></TD>
  76         <TD>Returns <A HREF='../macros/buffer_sizes.html'><CODE>default_filter_buffer_size</CODE></A>.</TD>
  77     </TR>
  78     <TR>
  79         <TD VALIGN="top">otherwise</TD>
  80         <TD>Returns <A HREF='../macros/buffer_sizes.html'><CODE>default_device_buffer_size</CODE></A>.</TD>
  81     </TR>
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  88 <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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  90     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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