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Added limited emplace() for older compilers

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Andrzej Krzemienski
2014-06-06 23:24:43 +02:00
parent dec71d338d
commit fdc98d17ca
12 changed files with 612 additions and 29 deletions
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15
doc/html/boost_optional/reference/detailed_semantics.html
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@ -1094,7 +1094,11 @@
<li class="listitem">
<span class="bold"><strong>Notes:</strong></span> <code class="computeroutput"><span class="identifier">T</span></code>
need not be <code class="computeroutput"><span class="identifier">MoveConstructible</span></code>
or <code class="computeroutput"><span class="identifier">MoveAssignable</span></code>.
or <code class="computeroutput"><span class="identifier">MoveAssignable</span></code>. On
compilers that do not support variadic templates, the signature falls
back to single-argument: <code class="computeroutput"><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">Arg</span><span class="special">&gt;</span> <span class="keyword">void</span> <span class="identifier">emplace</span><span class="special">(</span><span class="identifier">Arg</span><span class="special">&amp;&amp;</span> <span class="identifier">arg</span><span class="special">)</span></code>. On compilers that do not support rvalue
references, the signature falls back to two overloads: taking <code class="computeroutput"><span class="keyword">const</span></code> and non-<code class="computeroutput"><span class="keyword">const</span></code>
lvalue reference.
</li>
<li class="listitem">
<span class="bold"><strong>Exception Safety:</strong></span> If an exception is
@ -1102,6 +1106,15 @@
<code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
is <span class="emphasis"><em>uninitialized</em></span>.
</li>
<li class="listitem">
<span class="bold"><strong>Example:</strong></span>
<pre class="programlisting"><span class="identifier">T</span> <span class="identifier">v</span><span class="special">;</span>
<span class="identifier">optional</span><span class="special">&lt;</span><span class="keyword">const</span> <span class="identifier">T</span><span class="special">&gt;</span> <span class="identifier">opt</span><span class="special">;</span>
<span class="identifier">opt</span><span class="special">.</span><span class="identifier">emplace</span><span class="special">(</span><span class="number">0</span><span class="special">);</span> <span class="comment">// create in-place using ctor T(int)</span>
<span class="identifier">opt</span><span class="special">.</span><span class="identifier">emplace</span><span class="special">();</span> <span class="comment">// destroy previous and default-construct another T</span>
<span class="identifier">opt</span><span class="special">.</span><span class="identifier">emplace</span><span class="special">(</span><span class="identifier">v</span><span class="special">);</span> <span class="comment">// destroy and copy-construct in-place (no assignment called)</span>
</pre>
</li>
</ul></div>
<p>
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