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<H1 CLASS="title">Function Template <CODE>compose</CODE></H1>
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<DT><A href="#description">Description</A></DT>
<DT><A href="#headers">Headers</A></DT>
<DT><A href="#reference">Reference</A></DT>
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<A NAME="description"></A>
<H2>Description</H2>
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Given a Filter <CODE>f</CODE> and a Device <CODE>d</CODE>, we may construct a device <CODE>c</CODE> whose member functions are implemented by invoking the fundamental i/o operations <A HREF='../functions/read.html'><CODE>read</CODE></A>, <A HREF='../functions/write.html'><CODE>write</CODE></A>, <I>etc.</I> with <CODE>f</CODE> as the first argument and <CODE>d</CODE> as the second. Similarly, if we are given two filters <CODE>f1</CODE> and <CODE>f2</CODE>, we may construct a third filter <CODE>f3</CODE> whose member function templates are implemented by invoking the fundamental i/o operations <A HREF='../functions/read.html'><CODE>read</CODE></A>, <A HREF='../functions/write.html'><CODE>write</CODE></A>, <I>etc.</I>, with first argument equal to <CODE>f1</CODE> and second argument equal to the result of composing <CODE>f2</CODE> with the provided Device.
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The function template <A HREF='#composite'><CODE>composite</CODE></A> represents a Filter or Device which has been constructed in the above manner. The function template <A HREF='#compose'><CODE>compose</CODE></A> is an <A HREF='http://www.boost.org/more/generic_programming.html#object_generator' TARGET='_top'>object generator</A> which given a pair of components returns an appropriate instance of <CODE>composite</CODE>.
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The <A HREF='../guide/modes.html'>mode</A> of a <CODE>composite</CODE> is defined to provide a maximal subset of the common functionality of the two components. A <CODE>composite</CODE> is <A HREF='../concepts/closable.html'>Closable</A>, <A HREF='../concepts/flushable.html'>Flushable</A>, <A HREF='../concepts/localizable.html'>Localizable</A> and <A HREF='../concepts/optimally_buffered.html'>OptimallyBuffered</A>.
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<H2>Headers</H2>
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<DT><A CLASS="header" HREF="../../../../boost/iostreams/compose.hpp"><CODE><boost/iostreams/compose.hpp></CODE></A></DT>
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<A NAME="reference"></A>
<H2>Reference</H2>
<A NAME="synopsis"></A>
<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="#composite_template_params">Filter</A>, <SPAN CLASS="keyword">typename</SPAN> <A CLASS="documented" HREF="#composite_template_params">FilterOrDevice</A>>
<SPAN CLASS='keyword'>class</SPAN> <A CLASS='documented' HREF='#composite'>composite</A> {
<SPAN CLASS='keyword'>public:</SPAN>
<SPAN CLASS='keyword'>typedef</SPAN> <SPAN CLASS='keyword'>typename</SPAN> <A CLASS='documented' HREF='../guide/traits.html#char_type'>char_type_of</A><Filter>::type char_type;
<SPAN CLASS='keyword'>typedef</SPAN> <SPAN CLASS='omitted'>implementation-defined</SPAN> mode;
<A CLASS='documented' HREF='#composite_ctor'>composite</A>(<SPAN CLASS='keyword'>const</SPAN> Filter& first, [<SPAN CLASS='keyword'>const</SPAN>] FilterOrDevice& second);
<SPAN CLASS='comment'>// Filter or Device member functions</SPAN>
};
<SPAN CLASS="keyword">template</SPAN><<SPAN CLASS="keyword">typename</SPAN> <A CLASS="documented" HREF="#compose_template_params">Filter</A>, <SPAN CLASS="keyword">typename</SPAN> <A CLASS="documented" HREF="#compose_template_params">FilterOrDevice</A>>
<A CLASS='documented' HREF='#composite'>composite</A><Filter, FilterOrDevice>
<A CLASS='documented' HREF='#compose'>compose</A>(<SPAN CLASS='keyword'>const</SPAN> Filter& first, [<SPAN CLASS='keyword'>const</SPAN>] FilterOrDevice& second);
} } // End namespace boost::io</PRE>
<A NAME="composite"></A>
<H2>Class Template <CODE>composite</CODE></H2>
<A NAME="composite_template_params"></A>
<H4>Template parameters</H4>
<TABLE STYLE="margin-left:2em" BORDER=0 CELLPADDING=2>
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<TD VALIGN="top"><I>Filter</I></TD><TD WIDTH="2em" VALIGN="top">-</TD>
<TD>A model of <A HREF='../concepts/filter.html'>Filter</A></TD>
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<TD VALIGN="top"><I>FilterOrDevice</I></TD><TD WIDTH="2em" VALIGN="top">-</TD>
<TD>A model of <A HREF='../concepts/filter.html'>Filter</A> or <A HREF='../concepts/device.html'>Device</A></TD>
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<A NAME="composite_ctor"></A>
<H4><CODE>composite::composite</CODE></H4>
<PRE CLASS="broken_ie"> composite(<SPAN CLASS='keyword'>const</SPAN> Filter& first, [<SPAN CLASS='keyword'>const</SPAN>] FilterOrDevice& second);</PRE>
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Constructs an instance of <CODE>composite</CODE> based on the given components. If <CODE>FilterOrDevice</CODE> is a stream or stream buffer type, the second parameter is a non-<CODE>const</CODE> reference; otherwise it is a <CODE>const</CODE> reference.
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<A NAME="compose"></A>
<H2>Function Template <CODE>compose</CODE></H2>
<PRE CLASS="broken_ie"> composite(<SPAN CLASS='keyword'>const</SPAN> Filter& first, [<SPAN CLASS='keyword'>const</SPAN>] FilterOrDevice& second);</PRE>
<A NAME="compose_template_params"></A>
<H4>Template parameters</H4>
<TABLE STYLE="margin-left:2em" BORDER=0 CELLPADDING=2>
<TR>
<TR>
<TD VALIGN="top"><I>Filter</I></TD><TD WIDTH="2em" VALIGN="top">-</TD>
<TD>A model of <A HREF='../concepts/filter.html'>Filter</A></TD>
</TR>
<TR>
<TD VALIGN="top"><I>FilterOrDevice</I></TD><TD WIDTH="2em" VALIGN="top">-</TD>
<TD>A model of <A HREF='../concepts/filter.html'>Filter</A> or <A HREF='../concepts/device.html'>Device</A></TD>
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Returns an instance of an appropriate specialization of <CODE>composite</CODE> constructed from the given components. If <CODE>FilterOrDevice</CODE> is a stream or stream buffer type, the second parameter is a non-<CODE>const</CODE> reference; otherwise it is a <CODE>const</CODE> reference.
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<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>
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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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