ceph/src/boost/libs/proto/doc/reference/proto_typeof.xml

   1 <?xml version="1.0" encoding="utf-8"?>
   2 <!--
   3   Copyright 2012 Eric Niebler
   4
   5   Distributed under the Boost
   6   Software License, Version 1.0. (See accompanying
   7   file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   8   -->
   9 <header name="boost/proto/proto_typeof.hpp">
  10   <para>Boost.Typeof registrations for Proto's types, and definition of the
  11     <computeroutput><macroname>BOOST_PROTO_AUTO</macroname>()</computeroutput> macro.</para>
  12   <macro name="BOOST_PROTO_AUTO" kind="functionlike">
  13     <macro-parameter name="Var"/>
  14     <macro-parameter name="Expr"/>
  15     <purpose>For defining a local variable that stores a Proto expression template,
  16       deep-copying the expression so there are no dangling references.</purpose>
  17     <description>
  18       <para>
  19         To define a local variable <computeroutput>ex</computeroutput> that stores the expression
  20         <computeroutput><functionname alt="boost::proto::lit">proto::lit</functionname>(1) + 2</computeroutput>,
  21         do the following:<programlisting>BOOST_PROTO_AUTO( ex, <functionname alt="boost::proto::lit">proto::lit</functionname>(1) + 2 );</programlisting>.
  22         The above is equivalent to the following:
  23         <programlisting>BOOST_AUTO( ex, <functionname alt="boost::proto::deep_copy">proto::deep_copy</functionname>( <functionname alt="boost::proto::lit">proto::lit</functionname>(1) + 2 ) );</programlisting>
  24       </para>
  25     </description>
  26   </macro>
  27 </header>