| <html> |
| <head> |
| <meta http-equiv="Content-Type" content="text/html; charset=US-ASCII"> |
| <title>Function deconstruct</title> |
| <link rel="stylesheet" href="../../../../doc/src/boostbook.css" type="text/css"> |
| <meta name="generator" content="DocBook XSL Stylesheets V1.75.2"> |
| <link rel="home" href="../../index.html" title="The Boost C++ Libraries BoostBook Documentation Subset"> |
| <link rel="up" href="../../signals2/reference.html#header.boost.signals2.deconstruct_hpp" title="Header <boost/signals2/deconstruct.hpp>"> |
| <link rel="prev" href="scoped_connection.html" title="Class scoped_connection"> |
| <link rel="next" href="deconstruct_access.html" title="Class deconstruct_access"> |
| </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="scoped_connection.html"><img src="../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../../signals2/reference.html#header.boost.signals2.deconstruct_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="deconstruct_access.html"><img src="../../../../doc/src/images/next.png" alt="Next"></a> |
| </div> |
| <div class="refentry"> |
| <a name="boost.signals2.deconstruct"></a><div class="titlepage"></div> |
| <div class="refnamediv"> |
| <h2><span class="refentrytitle">Function deconstruct</span></h2> |
| <p>boost::signals2::deconstruct — Create a <code class="computeroutput">shared_ptr</code> with support for post-constructors and pre-destructors.</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="../../signals2/reference.html#header.boost.signals2.deconstruct_hpp" title="Header <boost/signals2/deconstruct.hpp>">boost/signals2/deconstruct.hpp</a>> |
| |
| </span> |
| <span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> T<span class="special">></span> <a class="link" href="postconstructor_invoker.html" title="Class postconstructor_invoker">postconstructor_invoker</a><span class="special"><</span><span class="identifier">T</span><span class="special">></span> <span class="identifier">deconstruct</span><span class="special">(</span><span class="special">)</span><span class="special">;</span> |
| <span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> T<span class="special">,</span> <span class="keyword">typename</span> A1<span class="special">></span> |
| <a class="link" href="postconstructor_invoker.html" title="Class postconstructor_invoker">postconstructor_invoker</a><span class="special"><</span><span class="identifier">T</span><span class="special">></span> <span class="identifier">deconstruct</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">A1</span> <span class="special">&</span> arg1<span class="special">)</span><span class="special">;</span> |
| <span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> T<span class="special">,</span> <span class="keyword">typename</span> A1<span class="special">,</span> <span class="keyword">typename</span> A2<span class="special">></span> |
| <a class="link" href="postconstructor_invoker.html" title="Class postconstructor_invoker">postconstructor_invoker</a><span class="special"><</span><span class="identifier">T</span><span class="special">></span> <span class="identifier">deconstruct</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">A1</span> <span class="special">&</span> arg1<span class="special">,</span> <span class="keyword">const</span> <span class="identifier">A2</span> <span class="special">&</span> arg2<span class="special">)</span><span class="special">;</span> |
| <span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> T<span class="special">,</span> <span class="keyword">typename</span> A1<span class="special">,</span> <span class="keyword">typename</span> A2, ...<span class="special">,</span> <span class="keyword">typename</span> AN<span class="special">></span> |
| <a class="link" href="postconstructor_invoker.html" title="Class postconstructor_invoker">postconstructor_invoker</a><span class="special"><</span><span class="identifier">T</span><span class="special">></span> |
| <span class="identifier">deconstruct</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">A1</span> <span class="special">&</span> arg1<span class="special">,</span> <span class="keyword">const</span> <span class="identifier">A2</span> <span class="special">&</span> arg2<span class="special">,</span> <span class="special">...</span><span class="special">,</span> <span class="keyword">const</span> <span class="identifier">AN</span> <span class="special">&</span> argN<span class="special">)</span><span class="special">;</span></pre></div> |
| <div class="refsect1"> |
| <a name="id2545223"></a><h2>Description</h2> |
| <p>Creates an object and its owning <code class="computeroutput">shared_ptr<T></code> |
| (wrapped inside a <code class="computeroutput"><a class="link" href="postconstructor_invoker.html" title="Class postconstructor_invoker">postconstructor_invoker</a></code>) |
| using only a single allocation, |
| in a manner similar |
| to that of <code class="computeroutput">boost::make_shared()</code>. In addition, <code class="computeroutput">deconstruct</code> |
| supports postconstructors and predestructors. The returned |
| <code class="computeroutput">shared_ptr</code> is wrapped inside a <code class="computeroutput"><a class="link" href="postconstructor_invoker.html" title="Class postconstructor_invoker">postconstructor_invoker</a></code> |
| in order to provide the user with an opportunity to pass arguments to a postconstructor, |
| while insuring the postconstructor is run before the wrapped |
| <code class="computeroutput">shared_ptr</code> is accessible. |
| </p> |
| <p> |
| In order to use <code class="computeroutput">deconstruct</code> you must define a postconstructor for your class. |
| More specifically, you must define |
| an <code class="computeroutput">adl_postconstruct</code> function which can be found via argument-dependent |
| lookup. Typically, this means defining an <code class="computeroutput">adl_postconstruct</code> function |
| in the same namespace as its associated class. See the reference for |
| <code class="computeroutput"><a class="link" href="postconstructor_invoker.html" title="Class postconstructor_invoker">postconstructor_invoker</a></code> |
| for a specification of what arguments are passed to the <code class="computeroutput">adl_postconstruct</code> |
| call. |
| </p> |
| <p> |
| Optionally, you may define a predestructor for your class. This is done by |
| defining an <code class="computeroutput">adl_predestruct</code> function which may be found |
| by argument-dependent lookup. The deleter of the <code class="computeroutput">shared_ptr</code> |
| created by <code class="computeroutput">deconstruct</code> will make an unqualified call to |
| <code class="computeroutput">adl_predestruct</code> with a single |
| argument: a pointer to the object which is about to be deleted. |
| As a convenience, the pointer will always be cast to point to a non-const type |
| before being passed to <code class="computeroutput">adl_predestruct</code>. |
| If no user-defined <code class="computeroutput">adl_predestruct</code> function is found via |
| argument-dependent lookup, a default function (which does nothing) will |
| be used. After <code class="computeroutput">adl_predestruct</code> is called, the deleter |
| will delete the object with |
| <code class="computeroutput">checked_delete</code>. |
| </p> |
| <p> |
| Any arguments passed to a |
| <code class="computeroutput">deconstruct()</code> call are forwarded to the matching constructor of the |
| template type |
| <code class="computeroutput">T</code>. Arguments may also be passed to the class' associated |
| <code class="computeroutput">adl_postconstruct</code> function by using the |
| <code class="computeroutput"><a class="link" href="postconstructor_invoker.html#id648330-bb">postconstructor_invoker::postconstruct()</a></code> methods. |
| </p> |
| <div class="variablelist"><table border="0"> |
| <col align="left" valign="top"> |
| <tbody> |
| <tr> |
| <td><p><span class="term">Notes:</span></p></td> |
| <td> |
| <p>If your compiler supports the C++0x features of rvalue references |
| and variadic templates, then <code class="computeroutput">deconstruct</code> will perform perfect |
| forwarding of arguments to the <code class="computeroutput">T</code> constructor, using |
| a prototype of: |
| </p> |
| <pre class="programlisting"><span class="keyword">template</span><span class="special"><</span> <span class="keyword">typename</span> <span class="identifier">T</span><span class="special">,</span> <span class="keyword">typename</span><span class="special">...</span> <span class="identifier">Args</span> <span class="special">></span> <span class="identifier">postconstructor_invoker</span><span class="special"><</span> <span class="identifier">T</span> <span class="special">></span> <span class="identifier">deconstruct</span><span class="special">(</span> <span class="identifier">Args</span> <span class="special">&&</span> <span class="special">...</span> <span class="identifier">args</span> <span class="special">)</span><span class="special">;</span></pre> |
| <p>Otherwise, argument forwarding is performed via const references, as specified in |
| the synopsis. In order to pass non-const references to a constructor, you will need |
| to wrap them in reference wrappers using boost::ref. |
| </p> |
| <p>You may give all the <code class="computeroutput">deconstruct</code> overloads access to your class' |
| private and protected constructors by |
| declaring <a class="link" href="deconstruct_access.html" title="Class deconstruct_access">deconstruct_access</a> a friend. Using private |
| constructors in conjunction with <a class="link" href="deconstruct_access.html" title="Class deconstruct_access">deconstruct_access</a> |
| can be useful to |
| ensure your objects are only created by <code class="computeroutput">deconstruct</code>, and thus |
| their postconstructors or predestructors will always be called. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term">Returns:</span></p></td> |
| <td><p>A <code class="computeroutput">postconstructor_invoker<T></code> owning a newly allocated object of |
| type <code class="computeroutput">T</code>.</p></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 © 2001-2004 Douglas Gregor<br>Copyright © 2007-2009 Frank Mori Hess<p>Distributed under the Boost |
| Software License, Version 1.0. (See accompanying file |
| <code class="filename">LICENSE_1_0.txt</code> 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="scoped_connection.html"><img src="../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../../signals2/reference.html#header.boost.signals2.deconstruct_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="deconstruct_access.html"><img src="../../../../doc/src/images/next.png" alt="Next"></a> |
| </div> |
| </body> |
| </html> |
