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rvalue ref overloads do not return by value

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Andrzej Krzemienski
2014-07-10 13:49:36 +02:00
parent 18b8c4bb18
commit fea4882f24
5 changed files with 25 additions and 74 deletions
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50
doc/html/boost_optional/reference/detailed_semantics.html
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@ -1334,12 +1334,8 @@
<span class="inlinemediaobject"><img src="../../images/space.png" alt="space"></span>
</p>
<a name="reference_optional_operator_asterisk_move"></a><div class="blockquote"><blockquote class="blockquote"><p>
<code class="computeroutput"><span class="identifier">T</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span></code>
<span class="emphasis"><em>(not a ref)</em></span><code class="computeroutput"><span class="special">&gt;::</span><span class="keyword">operator</span><span class="special">*()</span> <span class="special">&amp;&amp;;</span></code>
</p></blockquote></div>
<div class="blockquote"><blockquote class="blockquote"><p>
<code class="computeroutput"><span class="identifier">T</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span></code>
<span class="emphasis"><em>(not a ref)</em></span><code class="computeroutput"><span class="special">&gt;::</span><span class="keyword">operator</span><span class="special">*()</span> <span class="keyword">const</span><span class="special">&amp;&amp;;</span></code>
<code class="computeroutput"><span class="identifier">T</span><span class="special">&amp;&amp;</span>
<span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span></code> <span class="emphasis"><em>(not a ref)</em></span><code class="computeroutput"><span class="special">&gt;::</span><span class="keyword">operator</span><span class="special">*()</span> <span class="special">&amp;&amp;;</span></code>
</p></blockquote></div>
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
@ -1348,18 +1344,11 @@
<li class="listitem">
<span class="bold"><strong>Effects:</strong></span> Equivalent to <code class="computeroutput"><span class="keyword">return</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">move</span><span class="special">(*</span><span class="identifier">val</span><span class="special">);</span></code>.
</li>
<li class="listitem">
<span class="bold"><strong>Remarks:</strong></span> If <code class="computeroutput"><span class="identifier">T</span></code>
is not <code class="computeroutput"><span class="identifier">MoveConstructible</span></code>,
the program is ill-formed.
</li>
<li class="listitem">
<span class="bold"><strong>Notes:</strong></span> The requirement is asserted via
<code class="computeroutput"><span class="identifier">BOOST_ASSERT</span><span class="special">()</span></code>.
On GCC compiler the second overload is not present, as this compiler
incorrectly implements binding of references to const prvalues. On compilers
that do not support ref-qualifiers on member functions both these overloads
are not present.
On compilers that do not support ref-qualifiers on member functions this
overload is not present.
</li>
</ul></div>
<p>
@ -1377,11 +1366,6 @@
<code class="computeroutput"><span class="identifier">T</span> <span class="special">&amp;</span>
<span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&amp;&gt;::</span><span class="keyword">operator</span><span class="special">*()</span> <span class="special">&amp;&amp;</span> <span class="special">;</span></code>
</p></blockquote></div>
<div class="blockquote"><blockquote class="blockquote"><p>
<code class="computeroutput"><span class="identifier">T</span> <span class="special">&amp;</span>
<span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&amp;&gt;::</span><span class="keyword">operator</span><span class="special">*()</span> <span class="keyword">const</span><span class="special">&amp;&amp;</span>
<span class="special">;</span></code>
</p></blockquote></div>
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<span class="bold"><strong>Requires: </strong></span> <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> is initialized
@ -1396,11 +1380,9 @@
<li class="listitem">
<span class="bold"><strong>Notes:</strong></span> The requirement is asserted via
<code class="computeroutput"><span class="identifier">BOOST_ASSERT</span><span class="special">()</span></code>.
On GCC compiler the fourth overload is not present, as this compiler
incorrectly implements binding of references to const prvalues. On compilers
that do not support ref-qualifiers on member functions these four overloads
are replaced with the classical two: a <code class="computeroutput"><span class="keyword">const</span></code>
and non-<code class="computeroutput"><span class="keyword">const</span></code> member functions.
On compilers that do not support ref-qualifiers on member functions these
three overloads are replaced with the classical two: a <code class="computeroutput"><span class="keyword">const</span></code> and non-<code class="computeroutput"><span class="keyword">const</span></code>
member functions.
</li>
<li class="listitem">
<span class="bold"><strong>Example:</strong></span>
@ -1454,11 +1436,8 @@
<span class="inlinemediaobject"><img src="../../images/space.png" alt="space"></span>
</p>
<a name="reference_optional_value_move"></a><div class="blockquote"><blockquote class="blockquote"><p>
<code class="computeroutput"><span class="identifier">T</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;::</span><span class="identifier">value</span><span class="special">()</span> <span class="special">&amp;&amp;</span>
<span class="special">;</span></code>
</p></blockquote></div>
<div class="blockquote"><blockquote class="blockquote"><p>
<code class="computeroutput"><span class="identifier">T</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;::</span><span class="identifier">value</span><span class="special">()</span> <span class="keyword">const</span><span class="special">&amp;&amp;</span> <span class="special">;</span></code>
<code class="computeroutput"><span class="identifier">T</span><span class="special">&amp;&amp;</span>
<span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;::</span><span class="identifier">value</span><span class="special">()</span> <span class="special">&amp;&amp;</span> <span class="special">;</span></code>
</p></blockquote></div>
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
@ -1466,15 +1445,8 @@
<span class="identifier">bad_optional_access</span><span class="special">();</span></code>.
</li>
<li class="listitem">
<span class="bold"><strong>Remarks:</strong></span> If <code class="computeroutput"><span class="identifier">T</span></code>
is not <code class="computeroutput"><span class="identifier">MoveConstructible</span></code>,
the program is ill-formed.
</li>
<li class="listitem">
<span class="bold"><strong>Notes:</strong></span> On GCC compiler the second overload
is not present, as this compiler incorrectly implements binding of references
to const prvalues. On compilers that do not support ref-qualifiers on
member functions both these overloads are not present.
<span class="bold"><strong>Notes:</strong></span> On compilers that do not support
ref-qualifiers on member functions this overload is not present.
</li>
</ul></div>
<p>