projects / ceph.git / blame
| Commit | Line | Data |
|---|---|---|
| 7c673cae FG |
1 | <html> |
| 2 | <head> | |
| 3 | <meta http-equiv="Content-Type" content="text/html; charset=US-ASCII"> | |
| 4 | <title>is_copy_constructible</title> | |
| 5 | <link rel="stylesheet" href="../../../../../../doc/src/boostbook.css" type="text/css"> | |
| 6 | <meta name="generator" content="DocBook XSL Stylesheets V1.77.1"> | |
| 7 | <link rel="home" href="../../index.html" title="Chapter 1. Boost.TypeTraits"> | |
| 8 | <link rel="up" href="../reference.html" title="Alphabetical Reference"> | |
| 9 | <link rel="prev" href="is_copy_assignable.html" title="is_copy_assignable"> | |
| 10 | <link rel="next" href="is_default_constructible.html" title="is_default_constructible"> | |
| 11 | </head> | |
| 12 | <body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> | |
| 13 | <table cellpadding="2" width="100%"><tr> | |
| 14 | <td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../../boost.png"></td> | |
| 15 | <td align="center"><a href="../../../../../../index.html">Home</a></td> | |
| 16 | <td align="center"><a href="../../../../../../libs/libraries.htm">Libraries</a></td> | |
| 17 | <td align="center"><a href="http://www.boost.org/users/people.html">People</a></td> | |
| 18 | <td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td> | |
| 19 | <td align="center"><a href="../../../../../../more/index.htm">More</a></td> | |
| 20 | </tr></table> | |
| 21 | <hr> | |
| 22 | <div class="spirit-nav"> | |
| 23 | <a accesskey="p" href="is_copy_assignable.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../reference.html"><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="is_default_constructible.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a> | |
| 24 | </div> | |
| 25 | <div class="section"> | |
| 26 | <div class="titlepage"><div><div><h3 class="title"> | |
| 27 | <a name="boost_typetraits.reference.is_copy_constructible"></a><a class="link" href="is_copy_constructible.html" title="is_copy_constructible">is_copy_constructible</a> | |
| 28 | </h3></div></div></div> | |
| 29 | <pre class="programlisting"><span class="keyword">template</span> <span class="special"><</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">></span> | |
| 30 | <span class="keyword">struct</span> <span class="identifier">is_copy_constructible</span> <span class="special">:</span> <span class="keyword">public</span> <em class="replaceable"><code><a class="link" href="integral_constant.html" title="integral_constant">true_type</a>-or-<a class="link" href="integral_constant.html" title="integral_constant">false_type</a></code></em> <span class="special">{};</span> | |
| 31 | </pre> | |
| 32 | <p> | |
| 33 | <span class="bold"><strong>Inherits:</strong></span> If <code class="computeroutput"><span class="identifier">T</span></code> | |
| 34 | is a (possibly cv-qualified) type with a copy constructor, then inherits | |
| 35 | from <a class="link" href="integral_constant.html" title="integral_constant">true_type</a>, | |
| 36 | otherwise inherits from <a class="link" href="integral_constant.html" title="integral_constant">false_type</a>. | |
| 37 | Type <code class="computeroutput"><span class="identifier">T</span></code> must be a complete | |
| 38 | type. | |
| 39 | </p> | |
| 40 | <p> | |
| 41 | In other words, inherits from <a class="link" href="integral_constant.html" title="integral_constant">true_type</a> | |
| 42 | only if copy constructor of <code class="computeroutput"><span class="identifier">T</span></code> | |
| 43 | not marked with <code class="computeroutput"><span class="special">=</span> <span class="keyword">delete</span></code>, | |
| 44 | <code class="computeroutput"><span class="identifier">T</span></code> does not derives from | |
| 45 | <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">noncopyable</span></code> and does not marked with <code class="computeroutput"><span class="identifier">BOOST_MOVABLE_BUT_NOT_COPYABLE</span><span class="special">(</span><span class="identifier">T</span><span class="special">)</span></code>. | |
| 46 | </p> | |
| 47 | <p> | |
| 48 | <span class="bold"><strong>Compiler Compatibility:</strong></span> This trait requires | |
| 49 | the C++11 features <code class="computeroutput"><span class="keyword">decltype</span></code> | |
| 50 | and SFINAE-expression support for full support. | |
| 51 | </p> | |
| 52 | <p> | |
| 53 | If your compiler does not support C++11 deleted functions (<code class="computeroutput"><span class="special">=</span> <span class="keyword">delete</span></code>) | |
| 54 | or does not support SFINAE for the deleted constructors, then derive your | |
| 55 | classes from <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">noncopyable</span></code> or mark them with <code class="computeroutput"><span class="identifier">BOOST_MOVABLE_BUT_NOT_COPYABLE</span><span class="special">(</span><span class="identifier">T</span><span class="special">)</span></code> to show | |
| 56 | that class is noncopyable. | |
| 57 | </p> | |
| 58 | <p> | |
| 59 | The trait does not care about access modifiers, so if you see errors like | |
| 60 | this: | |
| 61 | </p> | |
| 62 | <pre class="programlisting"><span class="char">'T::T(const T&)'</span> <span class="identifier">is</span> <span class="keyword">private</span> | |
| 63 | <span class="identifier">boost</span><span class="special">/</span><span class="identifier">type_traits</span><span class="special">/</span><span class="identifier">is_copy_constructible</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">:</span><span class="number">68</span><span class="special">:</span><span class="number">5</span><span class="special">:</span> <span class="identifier">error</span><span class="special">:</span> <span class="identifier">within</span> <span class="keyword">this</span> <span class="identifier">context</span> | |
| 64 | </pre> | |
| 65 | <p> | |
| 66 | then you are trying to call that macro for a structure with private constructor: | |
| 67 | </p> | |
| 68 | <pre class="programlisting"><span class="keyword">struct</span> <span class="identifier">T</span> <span class="special">{</span> | |
| 69 | <span class="comment">// ...</span> | |
| 70 | <span class="keyword">private</span><span class="special">:</span> | |
| 71 | <span class="identifier">T</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">T</span> <span class="special">&);</span> | |
| 72 | <span class="comment">// ...</span> | |
| 73 | <span class="special">};</span> | |
| 74 | </pre> | |
| 75 | <p> | |
| 76 | To fix that you must modify your structure, explicitly marking it as noncopyable | |
| 77 | (<code class="computeroutput"><span class="special">=</span> <span class="keyword">delete</span></code>, | |
| 78 | <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">noncopyable</span></code> or <code class="computeroutput"><span class="identifier">BOOST_MOVABLE_BUT_NOT_COPYABLE</span><span class="special">(</span><span class="identifier">T</span><span class="special">)</span></code>) | |
| 79 | or explicitly <a class="link" href="../user_defined.html" title="User Defined Specializations">specialize trait</a>. | |
| 80 | </p> | |
| 81 | <p> | |
| 82 | <span class="bold"><strong>Header:</strong></span> <code class="computeroutput"> <span class="preprocessor">#include</span> | |
| 83 | <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">type_traits</span><span class="special">/</span><span class="identifier">is_copy_constructible</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span></code> | |
| 84 | or <code class="computeroutput"> <span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">type_traits</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span></code> | |
| 85 | </p> | |
| 86 | </div> | |
| 87 | <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> | |
| 88 | <td align="left"></td> | |
| 89 | <td align="right"><div class="copyright-footer">Copyright © 2000, 2011 Adobe Systems Inc, David Abrahams, | |
| 90 | Frederic Bron, Steve Cleary, Beman Dawes, Aleksey Gurtovoy, Howard Hinnant, | |
| 91 | Jesse Jones, Mat Marcus, Itay Maman, John Maddock, Alexander Nasonov, Thorsten | |
| 92 | Ottosen, Roman Perepelitsa, Robert Ramey, Jeremy Siek, Robert Stewart and Steven | |
| 93 | Watanabe<p> | |
| 94 | Distributed under the Boost Software License, Version 1.0. (See accompanying | |
| 95 | 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>) | |
| 96 | </p> | |
| 97 | </div></td> | |
| 98 | </tr></table> | |
| 99 | <hr> | |
| 100 | <div class="spirit-nav"> | |
| 101 | <a accesskey="p" href="is_copy_assignable.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../reference.html"><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="is_default_constructible.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a> | |
| 102 | </div> | |
| 103 | </body> | |
| 104 | </html> |