ceph/src/boost/libs/type_traits/doc/html/boost_typetraits/reference/is_nothrow_move_assignable.html

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  27 <a name="boost_typetraits.reference.is_nothrow_move_assignable"></a><a class="link" href="is_nothrow_move_assignable.html" title="is_nothrow_move_assignable">is_nothrow_move_assignable</a>
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  29 <pre class="programlisting"><span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">&gt;</span>
  30 <span class="keyword">struct</span> <span class="identifier">is_nothrow_move_assignable</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 non-throwing move assignment-operator
  35         or a type without move assignment-operator but with non-throwing assignment-operator,
  36         then inherits from <a class="link" href="integral_constant.html" title="integral_constant">true_type</a>,
  37         otherwise inherits from <a class="link" href="integral_constant.html" title="integral_constant">false_type</a>.
  38         Type <code class="computeroutput"><span class="identifier">T</span></code> must be a complete
  39         type.
  40       </p>
  41 <p>
  42         In other words, inherits from <a class="link" href="integral_constant.html" title="integral_constant">true_type</a>
  43         only if expression <code class="computeroutput"><span class="identifier">variable1</span> <span class="special">=</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">move</span><span class="special">(</span><span class="identifier">variable2</span><span class="special">)</span></code> won't throw (<code class="computeroutput"><span class="identifier">variable1</span></code>
  44         and <code class="computeroutput"><span class="identifier">variable2</span></code> are variables
  45         of type <code class="computeroutput"><span class="identifier">T</span></code>).
  46       </p>
  47 <p>
  48         <span class="bold"><strong>Compiler Compatibility:</strong></span> If the compiler
  49         does not support partial-specialization of class templates, then this template
  50         can not be used with function types.
  51       </p>
  52 <p>
  53         Without some (C++11 noexcept shall work correctly) help from the compiler,
  54         <code class="computeroutput"><span class="identifier">is_nothrow_move_assignable</span></code>
  55         will never report that a class or struct has a non-throwing assignment-operator;
  56         this is always safe, if possibly sub-optimal. Currently (June 2015) MSVC-12.0,
  57         Clang and GCC 4.7 have the necessary compiler support to ensure that this
  58         trait "just works".
  59       </p>
  60 <p>
  61         <span class="bold"><strong>Header:</strong></span> <code class="computeroutput"> <span class="preprocessor">#include</span>
  62         <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">type_traits</span><span class="special">/</span><span class="identifier">is_nothrow_move_assignable</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span></code>
  63         or <code class="computeroutput"> <span class="preprocessor">#include</span> <span class="special">&lt;</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">&gt;</span></code>
  64       </p>
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