ceph/src/boost/libs/smart_ptr/make_unique.html

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   8     <h1><img height="86" alt="boost.png (6897 bytes)" src="../../boost.png"
   9       width="277" align="middle" border="0">make_unique</h1>
  10     <p><a href="#introduction">Introduction</a><br>
  11       <a href="#synopsis">Synopsis</a><br>
  12       <a href="#common">Common Requirements</a><br>
  13       <a href="#functions">Free Functions</a><br>
  14       <a href="#history">History</a></p>
  15     <h2><a name="introduction">Introduction</a></h2>
  16     <p>The header file &lt;boost/make_unique.hpp&gt; provides overloaded
  17       function template <code>make_unique</code> for convenient creation of
  18       <code>unique_ptr</code> objects.</p>
  19     <h2><a name="synopsis">Synopsis</a></h2>
  20     <pre>namespace boost {
  21     template&lt;class U&gt; // U is not array
  22     unique_ptr&lt;U&gt; <a href="#functions">make_unique</a>();
  23
  24 #if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
  25     template&lt;class U, class... Args&gt; // U is not array
  26     unique_ptr&lt;U&gt; <a href="#functions">make_unique</a>(Args&amp;&amp;... args);
  27 #endif
  28
  29     template&lt;class U&gt; // U is not array
  30     unique_ptr&lt;U&gt; <a href="#functions">make_unique</a>(U&amp;&amp; value);
  31
  32     template&lt;class U&gt; // U is T[]
  33     unique_ptr&lt;U&gt; <a href="#functions">make_unique</a>(size_t size);
  34
  35     template&lt;class U&gt; // U is not array
  36     unique_ptr&lt;U&gt; <a href="#functions">make_unique_noinit</a>();
  37
  38     template&lt;class U&gt; // U is T[]
  39     unique_ptr&lt;U&gt; <a href="#functions">make_unique_noinit</a>(size_t size);
  40 }</pre>
  41     <h2><a name="common">Common Requirements</a></h2>
  42     <pre>template&lt;class U&gt;
  43     unique_ptr&lt;U&gt; make_unique(<em>args</em>);
  44 template&lt;class U&gt;
  45     unique_ptr&lt;U&gt; make_unique_noinit(<em>args</em>);</pre>
  46     <blockquote>
  47       <p><b>Effects:</b> Allocates memory for an object of type <code>U</code>
  48         (or <code>T[size]</code> when <code>U</code> is <code>T[]</code>,
  49         where <code>size</code> is determined from <code>args</code> as
  50         specified by the concrete overload). The object is initialized from
  51         <code>args</code> as specified by the concrete overload. If an
  52         exception is thrown, the functions have no effect.</p>
  53       <p><b>Returns:</b> A <code>unique_ptr</code> instance that stores and
  54         owns the address of the newly constructed object.</p>
  55       <p><b>Postconditions:</b> <code>r.get() != 0</code>, where
  56         <code>r</code> is the return value.</p>
  57       <p><b>Throws:</b> <code>bad_alloc</code>, or an exception thrown from
  58         the initialization of the object.</p>
  59       <p><b>Remarks:</b></p>
  60       <blockquote>
  61         <p>When an object of a non-array type <code>T</code> is specified to
  62           be initialized to a value <code>value</code>, or to
  63           <code>T(list...)</code>, where <code>list...</code> is a list of
  64           constructor arguments, <code>make_unique</code> shall perform this
  65           initialization via the expression <code>new T(value)</code> or
  66           <code>new T(list...)</code> respectively.</p>
  67         <p>When an object of type <code>T</code> is specified to be
  68           value-initialized, <code>make_unique</code> shall perform this
  69           initialization via the expression <code>new T()</code>.</p>
  70         <p>When an object of type <code>T</code> is specified to be
  71           default-initialized, <code>make_unique_noinit</code> shall perform
  72           this initialization via the expression <code>new T</code>.</p>
  73       </blockquote>
  74     </blockquote>
  75     <h2><a name="functions">Free Functions</a></h2>
  76     <pre>template&lt;class U, class... Args&gt;
  77 unique_ptr&lt;U&gt; make_unique(Args&amp;&amp;... args);</pre>
  78     <blockquote>
  79       <p><b>Returns:</b> A unique_ptr to an object of type <code>U</code>,
  80         initialized to <code>U(forward&lt;Args&gt;(args)...)</code>.</p>
  81       <p><b>Remarks:</b> This overload shall only participate in overload
  82         resolution when <code>U</code> is not an array type.</p>
  83       <p><b>Examples:</b></p>
  84       <blockquote>
  85         <pre>unique_ptr&lt;float&gt; p1 = boost::make_unique&lt;float&gt;();
  86 unique_ptr&lt;point&gt; p2 = boost::make_unique&lt;point&gt;(x, y);</pre>
  87       </blockquote>
  88     </blockquote>
  89     <pre>template&lt;class U&gt;
  90 unique_ptr&lt;U&gt; make_unique(U&amp;&amp; value);</pre>
  91     <blockquote>
  92       <p><b>Returns:</b> A unique_ptr to an object of type <code>U</code>,
  93         initialized to <code>move(value)</code>.</p>
  94       <p><b>Remarks:</b> This overload shall only participate in overload
  95         resolution when <code>U</code> is not an array type.</p>
  96       <p><b>Examples:</b></p>
  97       <blockquote>
  98         <pre>unique_ptr&lt;string&gt; p1 = boost::make_unique&lt;string&gt;({'a', 'b'});
  99 unique_ptr&lt;point&gt; p2 = boost::make_unique&lt;point&gt;({-10, 25});</pre>
 100       </blockquote>
 101     </blockquote>
 102     <pre>template&lt;class U&gt;
 103 unique_ptr&lt;U&gt; make_unique(size_t size);</pre>
 104     <blockquote>
 105       <p><b>Returns:</b> A unique_ptr to a value-initialized object of type
 106         <code>T[size]</code>.</p>
 107       <p><b>Remarks:</b> This overload shall only participate in overload
 108         resolution when <code>U</code> is of the form <code>T[]</code>.</p>
 109       <p><b>Examples:</b></p>
 110       <blockquote>
 111         <pre>unique_ptr&lt;double[]&gt; p1 = boost::make_unique&lt;double[]&gt;(4);
 112 unique_ptr&lt;int[][2]&gt; p2 = boost::make_unique&lt;int[][2]&gt;(2);</pre>
 113       </blockquote>
 114     </blockquote>
 115     <pre>template&lt;class U&gt;
 116 unique_ptr&lt;U&gt; make_unique_noinit();</pre>
 117     <blockquote>
 118       <p><b>Returns:</b> A unique_ptr to a default-initialized object of
 119         type <code>U</code>.</p>
 120       <p><b>Remarks:</b> This overload shall only participate in overload
 121         resolution when <code>U</code> is not an array type.</p>
 122       <p><b>Examples:</b></p>
 123       <blockquote>
 124         <pre>unique_ptr&lt;float&gt; p1 = boost::make_unique_noinit&lt;float&gt;();
 125 unique_ptr&lt;point&gt; p2 = boost::make_unique_noinit&lt;point&gt;();</pre>
 126       </blockquote>
 127     </blockquote>
 128     <pre>template&lt;class U&gt;
 129 unique_ptr&lt;U&gt; make_unique_noinit(size_t size);</pre>
 130     <blockquote>
 131       <p><b>Returns:</b> A unique_ptr to a default-initialized object of
 132         type <code>T[size]</code>.</p>
 133       <p><b>Remarks:</b> This overload shall only participate in overload
 134         resolution when <code>U</code> is of the form <code>T[]</code>.</p>
 135       <p><b>Examples:</b></p>
 136       <blockquote>
 137         <pre>unique_ptr&lt;double[]&gt; p1 = boost::make_unique_noinit&lt;double[]&gt;(4);
 138 unique_ptr&lt;int[][2]&gt; p2 = boost::make_unique_noinit&lt;int[][2]&gt;(2);</pre>
 139       </blockquote>
 140     </blockquote>
 141     <h2><a name="history">History</a></h2>
 142     <p>January 2014. Glen Fernandes contributed implementations of
 143       make_unique for objects and arrays.</p>
 144     <hr>
 145     <p>$Date$</p>
 146     <p><small>Copyright 2012-2014 Glen Fernandes. Distributed under the
 147       Boost Software License, Version 1.0. See accompanying file
 148       <a href="../../LICENSE_1_0.txt">LICENSE_1_0.txt</a> or copy at
 149       <a href="http://www.boost.org/LICENSE_1_0.txt">
 150       http://www.boost.org/LICENSE_1_0.txt</a>.</small></p>
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