<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=US-ASCII"> <title>Function call</title> <link rel="stylesheet" href="../../../../doc/src/boostbook.css" type="text/css"> <meta name="generator" content="DocBook XSL Stylesheets V1.78.1"> <link rel="home" href="../../index.html" title="The Boost C++ Libraries BoostBook Documentation Subset"> <link rel="up" href="../../boost_typeerasure/reference.html#header.boost.type_erasure.call_hpp" title="Header <boost/type_erasure/call.hpp>"> <link rel="prev" href="typeid_.html" title="Struct template typeid_"> <link rel="next" href="callable.html" title="Struct template callable"> </head> <body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> <table cellpadding="2" width="100%"><tr> <td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../boost.png"></td> <td align="center"><a href="../../../../index.html">Home</a></td> <td align="center"><a href="../../../../libs/libraries.htm">Libraries</a></td> <td align="center"><a href="http://www.boost.org/users/people.html">People</a></td> <td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td> <td align="center"><a href="../../../../more/index.htm">More</a></td> </tr></table> <hr> <div class="spirit-nav"> <a accesskey="p" href="typeid_.html"><img src="../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../../boost_typeerasure/reference.html#header.boost.type_erasure.call_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="callable.html"><img src="../../../../doc/src/images/next.png" alt="Next"></a> </div> <div class="refentry"> <a name="boost.type_erasure.call_idm45506884907840"></a><div class="titlepage"></div> <div class="refnamediv"> <h2><span class="refentrytitle">Function call</span></h2> <p>boost::type_erasure::call</p> </div> <h2 xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv-title">Synopsis</h2> <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="../../boost_typeerasure/reference.html#header.boost.type_erasure.call_hpp" title="Header <boost/type_erasure/call.hpp>">boost/type_erasure/call.hpp</a>> </span> <span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> Concept<span class="special">,</span> <span class="keyword">typename</span> Op<span class="special">,</span> <span class="keyword">class</span><span class="special">...</span> U<span class="special">></span> <span class="emphasis"><em><span class="identifier">unspecified</span></em></span> <span class="identifier">call</span><span class="special">(</span><span class="keyword">const</span> <a class="link" href="binding.html" title="Class template binding">binding</a><span class="special"><</span> <span class="identifier">Concept</span> <span class="special">></span> <span class="special">&</span> binding<span class="special">,</span> <span class="keyword">const</span> <span class="identifier">Op</span> <span class="special">&</span><span class="special">,</span> <span class="identifier">U</span> <span class="special">&&</span><span class="special">...</span> args<span class="special">)</span><span class="special">;</span> <span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> Op<span class="special">,</span> <span class="keyword">class</span><span class="special">...</span> U<span class="special">></span> <span class="emphasis"><em><span class="identifier">unspecified</span></em></span> <span class="identifier">call</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">Op</span> <span class="special">&</span><span class="special">,</span> <span class="identifier">U</span> <span class="special">&&</span><span class="special">...</span> args<span class="special">)</span><span class="special">;</span></pre></div> <div class="refsect1"> <a name="idm45555079389120"></a><h2>Description</h2> <p>Dispatches a type erased function.</p> <p><code class="computeroutput">Op</code> must be a primitive concept which is present in <code class="computeroutput">Concept</code>. Its signature determines how the arguments of <code class="computeroutput"><a class="link" href="call_idm45506884907840.html" title="Function call">call</a></code> are handled. If the argument is a <code class="computeroutput"><a class="link" href="placeholder.html" title="Struct placeholder">placeholder</a></code>, <code class="computeroutput"><a class="link" href="call_idm45506884907840.html" title="Function call">call</a></code> expects an <code class="computeroutput"><a class="link" href="any.html" title="Class template any">any</a></code> using that <code class="computeroutput"><a class="link" href="placeholder.html" title="Struct placeholder">placeholder</a></code>. This <code class="computeroutput"><a class="link" href="any.html" title="Class template any">any</a></code> is unwrapped by <code class="computeroutput"><a class="link" href="call_idm45506884907840.html" title="Function call">call</a></code>. The type that it stores must be the same type specified by <code class="computeroutput">binding</code>. Any arguments that are not placeholders in the signature of <code class="computeroutput">Op</code> are passed through unchanged.</p> <p>If <code class="computeroutput">binding</code> is not specified, it will be deduced from the arguments. Naturally this requires at least one argument to be an <code class="computeroutput"><a class="link" href="any.html" title="Class template any">any</a></code>. In this case, all <code class="computeroutput"><a class="link" href="any.html" title="Class template any">any</a></code> arguments must have the same <code class="computeroutput"><a class="link" href="binding.html" title="Class template binding">binding</a></code>.</p> <p> Example:</p> <pre class="programlisting"><span class="keyword">typedef</span> <span class="identifier">mpl</span><span class="special">::</span><span class="identifier">vector</span><span class="special"><</span> <span class="identifier">copy_constructible</span><span class="special"><</span><span class="identifier">_b</span><span class="special">></span><span class="special">,</span> <span class="identifier">addable</span><span class="special"><</span><span class="identifier">_a</span><span class="special">,</span> <span class="keyword">int</span><span class="special">,</span> <span class="identifier">_b</span><span class="special">></span> <span class="special">></span> <span class="identifier">concept</span><span class="special">;</span> <span class="identifier">any</span><span class="special"><</span><span class="identifier">concept</span><span class="special">,</span> <span class="identifier">_a</span><span class="special">></span> <span class="identifier">a</span> <span class="special">=</span> <span class="special">...</span><span class="special">;</span> <span class="identifier">any</span><span class="special"><</span><span class="identifier">concept</span><span class="special">,</span> <span class="identifier">_b</span><span class="special">></span> <span class="identifier">b</span><span class="special">(</span><span class="identifier">call</span><span class="special">(</span><span class="identifier">addable</span><span class="special"><</span><span class="identifier">_a</span><span class="special">,</span> <span class="keyword">int</span><span class="special">,</span> <span class="identifier">_b</span><span class="special">></span><span class="special">(</span><span class="special">)</span><span class="special">,</span> <span class="identifier">a</span><span class="special">,</span> <span class="number">10</span><span class="special">)</span><span class="special">)</span><span class="special">;</span> </pre> <p>The signature of <code class="computeroutput"><a class="link" href="addable.html" title="Struct template addable">addable</a></code> is <code class="computeroutput">_b(const _a&, const int&)</code> </p> <div class="variablelist"><table border="0" class="variablelist compact"> <colgroup> <col align="left" valign="top"> <col> </colgroup> <tbody> <tr> <td><p><span class="term">Returns:</span></p></td> <td><p>The result of the operation. If the result type of the signature of <code class="computeroutput">Op</code> is a placeholder, the result will be converted to the appropriate <a class="link" href="any.html" title="Class template any">any</a> type.</p></td> </tr> <tr> <td><p><span class="term">Throws:</span></p></td> <td> <a class="link" href="../bad_function_call.html" title="Class bad_function_call">bad_function_call</a> if <a class="link" href="relaxed.html" title="Struct relaxed">relaxed</a> is in <code class="computeroutput">Concept</code> and there is a type mismatch.</td> </tr> </tbody> </table></div> </div> </div> <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> <td align="left"></td> <td align="right"><div class="copyright-footer">Copyright © 2011-2013 Steven Watanabe<p> 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" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>) </p> </div></td> </tr></table> <hr> <div class="spirit-nav"> <a accesskey="p" href="typeid_.html"><img src="../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../../boost_typeerasure/reference.html#header.boost.type_erasure.call_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="callable.html"><img src="../../../../doc/src/images/next.png" alt="Next"></a> </div> </body> </html>