1<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 2<html> 3<head> 4<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 5<title>Macro BOOST_MOVE_RET</title> 6<link rel="stylesheet" href="../../doc/src/boostbook.css" type="text/css"> 7<meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> 8<link rel="home" href="index.html" title="The Boost C++ Libraries BoostBook Documentation Subset"> 9<link rel="up" href="move/reference.html#header.boost.move.core_hpp" title="Header <boost/move/core.hpp>"> 10<link rel="prev" href="BOOST_FWD_REF.html" title="Macro BOOST_FWD_REF"> 11<link rel="next" href="BOOST_MOVE_BASE.html" title="Macro BOOST_MOVE_BASE"> 12</head> 13<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> 14<table cellpadding="2" width="100%"><tr> 15<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../boost.png"></td> 16<td align="center"><a href="../../index.html">Home</a></td> 17<td align="center"><a href="../../libs/libraries.htm">Libraries</a></td> 18<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td> 19<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td> 20<td align="center"><a href="../../more/index.htm">More</a></td> 21</tr></table> 22<hr> 23<div class="spirit-nav"> 24<a accesskey="p" href="BOOST_FWD_REF.html"><img src="../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="move/reference.html#header.boost.move.core_hpp"><img src="../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="index.html"><img src="../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="BOOST_MOVE_BASE.html"><img src="../../doc/src/images/next.png" alt="Next"></a> 25</div> 26<div class="refentry"> 27<a name="BOOST_MOVE_RET"></a><div class="titlepage"></div> 28<div class="refnamediv"> 29<h2><span class="refentrytitle">Macro BOOST_MOVE_RET</span></h2> 30<p>BOOST_MOVE_RET</p> 31</div> 32<h2 xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv-title">Synopsis</h2> 33<div xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv"><pre class="synopsis"><span class="comment">// In header: <<a class="link" href="move/reference.html#header.boost.move.core_hpp" title="Header <boost/move/core.hpp>">boost/move/core.hpp</a>> 34 35</span>BOOST_MOVE_RET(RET_TYPE, REF)</pre></div> 36<div class="refsect1"> 37<a name="id-1.3.26.20.8.16.4"></a><h2>Description</h2> 38<p>This macro is used to achieve portable move return semantics. The C++11 Standard allows implicit move returns when the object to be returned is designated by a lvalue and:</p> 39<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 40<li class="listitem"><p>The criteria for elision of a copy operation are met OR</p></li> 41<li class="listitem"><p>The criteria would be met save for the fact that the source object is a function parameter</p></li> 42</ul></div> 43<p> 44</p> 45<p>For C++11 conforming compilers this macros only yields to REF: <code class="computeroutput">return BOOST_MOVE_RET(RET_TYPE, REF);</code> -> <code class="computeroutput">return REF;</code></p> 46<p>For compilers without rvalue references this macro does an explicit move if the move emulation is activated and the return type (RET_TYPE) is not a reference.</p> 47<p>For non-conforming compilers with rvalue references like Visual 2010 & 2012, an explicit move is performed if RET_TYPE is not a reference.</p> 48<p><span class="bold"><strong>Caution</strong></span>: When using this macro in non-conforming or C++03 compilers, a move will be performed even if the C++11 standard does not allow it (e.g. returning a static variable). The user is responsible for using this macro only to return local objects that met C++11 criteria. </p> 49</div> 50</div> 51<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 52<td align="left"></td> 53<td align="right"><div class="copyright-footer">Copyright © 2008-2014 Ion Gaztanaga<p> 54 Distributed under the Boost Software License, Version 1.0. (See accompanying 55 file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>) 56 </p> 57</div></td> 58</tr></table> 59<hr> 60<div class="spirit-nav"> 61<a accesskey="p" href="BOOST_FWD_REF.html"><img src="../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="move/reference.html#header.boost.move.core_hpp"><img src="../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="index.html"><img src="../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="BOOST_MOVE_BASE.html"><img src="../../doc/src/images/next.png" alt="Next"></a> 62</div> 63</body> 64</html> 65
