forked from boostorg/optional
Updated documentation; fixed optional::swap
This commit is contained in:
Andrzej Krzemienski
@ -72,7 +72,7 @@
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<span class="inlinemediaobject"><img src="../images/space.png" alt="space"></span>
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</p>
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<a name="reference_optional_constructor"></a><div class="blockquote"><blockquote class="blockquote"><p>
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<code class="computeroutput"><span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">>::</span><span class="identifier">optional</span><span class="special">();</span></code>
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<code class="computeroutput"><span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">>::</span><span class="identifier">optional</span><span class="special">()</span> <span class="keyword">noexcept</span><span class="special">;</span></code>
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</p></blockquote></div>
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<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
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<li class="listitem">
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@ -82,11 +82,7 @@
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<span class="bold"><strong>Postconditions:</strong></span> <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> is <span class="underline">uninitialized</span>.
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</li>
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<li class="listitem">
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<span class="bold"><strong>Throws:</strong></span> Nothing.
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</li>
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<li class="listitem">
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Notes: T's default constructor <span class="underline">is not</span>
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called.
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<span class="bold"><strong>Notes:</strong></span> T's default constructor <span class="underline">is not</span> called.
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</li>
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<li class="listitem">
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<span class="bold"><strong>Example:</strong></span>
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@ -99,7 +95,7 @@
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<span class="inlinemediaobject"><img src="../images/space.png" alt="space"></span>
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</p>
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<a name="reference_optional_constructor_none_t"></a><div class="blockquote"><blockquote class="blockquote"><p>
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<code class="computeroutput"><span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">>::</span><span class="identifier">optional</span><span class="special">(</span> <span class="identifier">none_t</span> <span class="special">);</span></code>
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<code class="computeroutput"><span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">>::</span><span class="identifier">optional</span><span class="special">(</span> <span class="identifier">none_t</span> <span class="special">)</span> <span class="keyword">noexcept</span><span class="special">;</span></code>
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</p></blockquote></div>
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<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
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<li class="listitem">
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@ -109,9 +105,6 @@
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<li class="listitem">
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<span class="bold"><strong>Postconditions:</strong></span> <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> is <span class="underline">uninitialized</span>.
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</li>
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<li class="listitem">
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<span class="bold"><strong>Throws:</strong></span> Nothing.
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</li>
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<li class="listitem">
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<span class="bold"><strong>Notes:</strong></span> <code class="computeroutput"><span class="identifier">T</span></code>'s
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default constructor <span class="underline">is not</span> called.
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@ -132,12 +125,16 @@
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<code class="computeroutput"><span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span> </code><span class="emphasis"><em>(not a ref)</em></span><code class="computeroutput"><span class="special">>::</span><span class="identifier">optional</span><span class="special">(</span> <span class="identifier">T</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">v</span> <span class="special">)</span></code>
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</p></blockquote></div>
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<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
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<li class="listitem">
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<span class="bold"><strong>Requires:</strong></span> <code class="computeroutput"><span class="identifier">is_copy_constructible</span><span class="special"><</span><span class="identifier">T</span><span class="special">>::</span><span class="identifier">value</span></code>
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is <code class="computeroutput"><span class="keyword">true</span></code>.
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</li>
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<li class="listitem">
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<span class="bold"><strong>Effect:</strong></span> Directly-Constructs an <code class="computeroutput"><span class="identifier">optional</span></code>.
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</li>
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<li class="listitem">
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<span class="bold"><strong>Postconditions:</strong></span> <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> is <span class="underline">initialized</span>
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and its value is a<span class="emphasis"><em>copy</em></span> of <code class="computeroutput"><span class="identifier">v</span></code>.
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and its value is a <span class="emphasis"><em>copy</em></span> of <code class="computeroutput"><span class="identifier">v</span></code>.
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</li>
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<li class="listitem">
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<span class="bold"><strong>Throws:</strong></span> Whatever <code class="computeroutput"><span class="identifier">T</span><span class="special">::</span><span class="identifier">T</span><span class="special">(</span>
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@ -193,6 +190,58 @@
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</pre>
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</li>
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</ul></div>
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<p>
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<span class="inlinemediaobject"><img src="../images/space.png" alt="space"></span>
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</p>
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<a name="reference_optional_constructor_move_value"></a><div class="blockquote"><blockquote class="blockquote"><p>
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<code class="computeroutput"><span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span> </code><span class="emphasis"><em>(not a ref)</em></span><code class="computeroutput"><span class="special">>::</span><span class="identifier">optional</span><span class="special">(</span> <span class="identifier">T</span><span class="special">&&</span>
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<span class="identifier">v</span> <span class="special">)</span></code>
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</p></blockquote></div>
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<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
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<li class="listitem">
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<span class="bold"><strong>Requires:</strong></span> <code class="computeroutput"><span class="identifier">is_move_constructible</span><span class="special"><</span><span class="identifier">T</span><span class="special">>::</span><span class="identifier">value</span></code>
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is <code class="computeroutput"><span class="keyword">true</span></code>.
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</li>
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<li class="listitem">
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<span class="bold"><strong>Effect:</strong></span> Directly-Move-Constructs an <code class="computeroutput"><span class="identifier">optional</span></code>.
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</li>
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<li class="listitem">
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<span class="bold"><strong>Postconditions:</strong></span> <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> is <span class="underline">initialized</span>
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and its value is move-constructed from <code class="computeroutput"><span class="identifier">v</span></code>.
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</li>
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<li class="listitem">
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<span class="bold"><strong>Throws:</strong></span> Whatever <code class="computeroutput"><span class="identifier">T</span><span class="special">::</span><span class="identifier">T</span><span class="special">(</span>
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<span class="identifier">T</span><span class="special">&&</span>
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<span class="special">)</span></code> throws.
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</li>
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<li class="listitem">
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<span class="bold"><strong>Notes: </strong></span> <code class="computeroutput"><span class="identifier">T</span><span class="special">::</span><span class="identifier">T</span><span class="special">(</span>
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<span class="identifier">T</span><span class="special">&&</span>
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<span class="special">)</span></code> is called.
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</li>
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<li class="listitem">
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<span class="bold"><strong>Exception Safety:</strong></span> Exceptions can only
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be thrown during <code class="computeroutput"><span class="identifier">T</span><span class="special">::</span><span class="identifier">T</span><span class="special">(</span> <span class="identifier">T</span><span class="special">&&</span> <span class="special">);</span></code>
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in that case, the state of <code class="computeroutput"><span class="identifier">v</span></code>
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is determined by exception safety guarantees for <code class="computeroutput"><span class="identifier">T</span><span class="special">::</span><span class="identifier">T</span><span class="special">(</span><span class="identifier">T</span><span class="special">&&)</span></code>.
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</li>
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<li class="listitem">
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<span class="bold"><strong>Example:</strong></span>
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<pre class="programlisting"><span class="identifier">T</span> <span class="identifier">v1</span><span class="special">,</span> <span class="identifier">v2</span><span class="special">;</span>
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<span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">></span> <span class="identifier">opt</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">v1</span><span class="special">));</span>
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<span class="identifier">assert</span> <span class="special">(</span> <span class="special">*</span><span class="identifier">opt</span> <span class="special">==</span> <span class="identifier">v2</span> <span class="special">)</span> <span class="special">;</span>
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</pre>
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</li>
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</ul></div>
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<p>
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<span class="inlinemediaobject"><img src="../images/space.png" alt="space"></span>
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</p>
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<div class="blockquote"><blockquote class="blockquote"><p>
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<code class="computeroutput"><span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">&>::</span><span class="identifier">optional</span><span class="special">(</span> <span class="identifier">T</span><span class="special">&&</span> <span class="identifier">ref</span> <span class="special">)</span> <span class="special">=</span> <span class="keyword">delete</span></code>
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</p></blockquote></div>
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<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem">
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<span class="bold"><strong>Notes:</strong></span> This constructor is deleted
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</li></ul></div>
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<p>
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<span class="inlinemediaobject"><img src="../images/space.png" alt="space"></span>
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</p>
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@ -229,6 +278,10 @@
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<code class="computeroutput"><span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span> </code><span class="emphasis"><em>(not a ref)</em></span><code class="computeroutput"><span class="special">>::</span><span class="identifier">optional</span><span class="special">(</span> <span class="identifier">optional</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">rhs</span> <span class="special">);</span></code>
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</p></blockquote></div>
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<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
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<li class="listitem">
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<span class="bold"><strong>Requires:</strong></span> <code class="computeroutput"><span class="identifier">is_copy_constructible</span><span class="special"><</span><span class="identifier">T</span><span class="special">>::</span><span class="identifier">value</span></code>
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is <code class="computeroutput"><span class="keyword">true</span></code>.
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</li>
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<li class="listitem">
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<span class="bold"><strong>Effect:</strong></span> Copy-Constructs an <code class="computeroutput"><span class="identifier">optional</span></code>.
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</li>
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@ -320,6 +373,116 @@
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</pre>
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</li>
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</ul></div>
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<p>
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<span class="inlinemediaobject"><img src="../images/space.png" alt="space"></span>
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</p>
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<a name="reference_optional_move_constructor_optional"></a><div class="blockquote"><blockquote class="blockquote"><p>
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<code class="computeroutput"><span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span> </code><span class="emphasis"><em>(not a ref)</em></span><code class="computeroutput"><span class="special">>::</span><span class="identifier">optional</span><span class="special">(</span> <span class="identifier">optional</span><span class="special">&&</span> <span class="identifier">rhs</span>
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<span class="special">)</span> <span class="keyword">noexcept</span><span class="special">(</span></code><span class="emphasis"><em>see below</em></span><code class="computeroutput"><span class="special">);</span></code>
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</p></blockquote></div>
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<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
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<li class="listitem">
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<span class="bold"><strong>Requires:</strong></span> <code class="computeroutput"><span class="identifier">is_move_constructible</span><span class="special"><</span><span class="identifier">T</span><span class="special">>::</span><span class="identifier">value</span></code>
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is <code class="computeroutput"><span class="keyword">true</span></code>.
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</li>
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<li class="listitem">
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<span class="bold"><strong>Effect:</strong></span> Move-constructs an <code class="computeroutput"><span class="identifier">optional</span></code>.
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</li>
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<li class="listitem">
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<span class="bold"><strong>Postconditions:</strong></span> If <code class="computeroutput"><span class="identifier">rhs</span></code>
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is initialized, <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
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is initialized and its value is move constructed from <code class="computeroutput"><span class="identifier">rhs</span></code>;
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else <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
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is uninitialized.
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</li>
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<li class="listitem">
|
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<span class="bold"><strong>Throws:</strong></span> Whatever <code class="computeroutput"><span class="identifier">T</span><span class="special">::</span><span class="identifier">T</span><span class="special">(</span>
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<span class="identifier">T</span><span class="special">&&</span>
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<span class="special">)</span></code> throws.
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</li>
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<li class="listitem">
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<span class="bold"><strong>Notes:</strong></span> If <code class="computeroutput"><span class="identifier">rhs</span></code>
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is initialized, <code class="computeroutput"><span class="identifier">T</span><span class="special">::</span><span class="identifier">T</span><span class="special">(</span> <span class="identifier">T</span>
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<span class="special">&&</span> <span class="special">)</span></code>
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is called. The expression inside <code class="computeroutput"><span class="keyword">noexcept</span></code>
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is equivalent to <code class="computeroutput"><span class="identifier">is_nothrow_move_constructible</span><span class="special"><</span><span class="identifier">T</span><span class="special">>::</span><span class="identifier">value</span></code>.
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</li>
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<li class="listitem">
|
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<span class="bold"><strong>Exception Safety:</strong></span> Exceptions can only
|
||||
be thrown during <code class="computeroutput"><span class="identifier">T</span><span class="special">::</span><span class="identifier">T</span><span class="special">(</span> <span class="identifier">T</span><span class="special">&&</span> <span class="special">);</span></code>
|
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in that case, <code class="computeroutput"><span class="identifier">rhs</span></code> remains
|
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initialized and the value of <code class="computeroutput"><span class="special">*</span><span class="identifier">rhs</span></code> is determined by exception safety
|
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of <code class="computeroutput"><span class="identifier">T</span><span class="special">::</span><span class="identifier">T</span><span class="special">(</span><span class="identifier">T</span><span class="special">&&)</span></code>.
|
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</li>
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<li class="listitem">
|
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<span class="bold"><strong>Example:</strong></span>
|
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<pre class="programlisting"><span class="identifier">optional</span><span class="special"><</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">unique_ptr</span><span class="special"><</span><span class="identifier">T</span><span class="special">>></span> <span class="identifier">uninit</span> <span class="special">;</span>
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<span class="identifier">assert</span> <span class="special">(!</span><span class="identifier">uninit</span><span class="special">);</span>
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<span class="identifier">optional</span><span class="special"><</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">unique_ptr</span><span class="special"><</span><span class="identifier">T</span><span class="special">>></span> <span class="identifier">uinit2</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">uninit</span><span class="special">)</span> <span class="special">)</span> <span class="special">;</span>
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<span class="identifier">assert</span> <span class="special">(</span> <span class="identifier">uninit2</span> <span class="special">==</span> <span class="identifier">uninit</span> <span class="special">);</span>
|
||||
|
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<span class="identifier">optional</span><span class="special"><</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">unique_ptr</span><span class="special"><</span><span class="identifier">T</span><span class="special">>></span> <span class="identifier">init</span><span class="special">(</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">uniqye_ptr</span><span class="special"><</span><span class="identifier">T</span><span class="special">>(</span><span class="keyword">new</span> <span class="identifier">T</span><span class="special">(</span><span class="number">2</span><span class="special">))</span> <span class="special">);</span>
|
||||
<span class="identifier">assert</span> <span class="special">(</span> <span class="special">**</span><span class="identifier">init</span> <span class="special">==</span> <span class="identifier">T</span><span class="special">(</span><span class="number">2</span><span class="special">)</span> <span class="special">)</span> <span class="special">;</span>
|
||||
|
||||
<span class="identifier">optional</span><span class="special"><</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">unique_ptr</span><span class="special"><</span><span class="identifier">T</span><span class="special">>></span> <span class="identifier">init2</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">init</span><span class="special">)</span> <span class="special">)</span> <span class="special">;</span>
|
||||
<span class="identifier">assert</span> <span class="special">(</span> <span class="identifier">init</span> <span class="special">);</span>
|
||||
<span class="identifier">assert</span> <span class="special">(</span> <span class="special">*</span><span class="identifier">init</span> <span class="special">==</span> <span class="keyword">nullptr</span> <span class="special">);</span>
|
||||
<span class="identifier">assert</span> <span class="special">(</span> <span class="identifier">init2</span> <span class="special">);</span>
|
||||
<span class="identifier">assert</span> <span class="special">(</span> <span class="special">**</span><span class="identifier">init2</span> <span class="special">==</span> <span class="identifier">T</span><span class="special">(</span><span class="number">2</span><span class="special">)</span> <span class="special">)</span> <span class="special">;</span>
|
||||
</pre>
|
||||
</li>
|
||||
</ul></div>
|
||||
<p>
|
||||
<span class="inlinemediaobject"><img src="../images/space.png" alt="space"></span>
|
||||
</p>
|
||||
<div class="blockquote"><blockquote class="blockquote"><p>
|
||||
<code class="computeroutput"><span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">&>::</span><span class="identifier">optional</span><span class="special">(</span> <span class="identifier">optional</span> <span class="special">&&</span>
|
||||
<span class="identifier">rhs</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>Effect:</strong></span> Move-Constructs an <code class="computeroutput"><span class="identifier">optional</span></code>.
|
||||
</li>
|
||||
<li class="listitem">
|
||||
<span class="bold"><strong>Postconditions:</strong></span> If <code class="computeroutput"><span class="identifier">rhs</span></code>
|
||||
is initialized, <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
|
||||
is initialized and its value is another reference to the same object referenced
|
||||
by <code class="computeroutput"><span class="special">*</span><span class="identifier">rhs</span></code>;
|
||||
else <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
|
||||
is uninitialized.
|
||||
</li>
|
||||
<li class="listitem">
|
||||
<span class="bold"><strong>Throws:</strong></span> Nothing.
|
||||
</li>
|
||||
<li class="listitem">
|
||||
<span class="bold"><strong>Notes:</strong></span> If <code class="computeroutput"><span class="identifier">rhs</span></code>
|
||||
is initialized, both <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
|
||||
and <code class="computeroutput"><span class="special">*</span><span class="identifier">rhs</span></code>
|
||||
will reefer to the same object (they alias).
|
||||
</li>
|
||||
<li class="listitem">
|
||||
<span class="bold"><strong>Example:</strong></span>
|
||||
<pre class="programlisting"><span class="identifier">optional</span><span class="special"><</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">unique_ptr</span><span class="special"><</span><span class="identifier">T</span><span class="special">>&></span> <span class="identifier">uninit</span> <span class="special">;</span>
|
||||
<span class="identifier">assert</span> <span class="special">(!</span><span class="identifier">uninit</span><span class="special">);</span>
|
||||
|
||||
<span class="identifier">optional</span><span class="special"><</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">unique_ptr</span><span class="special"><</span><span class="identifier">T</span><span class="special">>&></span> <span class="identifier">uinit2</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">uninit</span><span class="special">)</span> <span class="special">)</span> <span class="special">;</span>
|
||||
<span class="identifier">assert</span> <span class="special">(</span> <span class="identifier">uninit2</span> <span class="special">==</span> <span class="identifier">uninit</span> <span class="special">);</span>
|
||||
|
||||
<span class="identifier">std</span><span class="special">::</span><span class="identifier">unique_ptr</span><span class="special"><</span><span class="identifier">T</span><span class="special">></span> <span class="identifier">v</span><span class="special">(</span><span class="keyword">new</span> <span class="identifier">T</span><span class="special">(</span><span class="number">2</span><span class="special">))</span> <span class="special">;</span>
|
||||
<span class="identifier">optional</span><span class="special"><</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">unique_ptr</span><span class="special"><</span><span class="identifier">T</span><span class="special">>&></span> <span class="identifier">init</span><span class="special">(</span><span class="identifier">v</span><span class="special">);</span>
|
||||
<span class="identifier">assert</span> <span class="special">(</span> <span class="special">*</span><span class="identifier">init</span> <span class="special">==</span> <span class="identifier">v</span> <span class="special">)</span> <span class="special">;</span>
|
||||
|
||||
<span class="identifier">optional</span><span class="special"><</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">unique_ptr</span><span class="special"><</span><span class="identifier">T</span><span class="special">>&></span> <span class="identifier">init2</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">init</span><span class="special">)</span> <span class="special">)</span> <span class="special">;</span>
|
||||
<span class="identifier">assert</span> <span class="special">(</span> <span class="special">*</span><span class="identifier">init2</span> <span class="special">==</span> <span class="identifier">v</span> <span class="special">)</span> <span class="special">;</span>
|
||||
|
||||
<span class="special">*</span><span class="identifier">v</span> <span class="special">=</span> <span class="number">3</span> <span class="special">;</span>
|
||||
|
||||
<span class="identifier">assert</span> <span class="special">(</span> <span class="special">**</span><span class="identifier">init</span> <span class="special">==</span> <span class="number">3</span> <span class="special">)</span> <span class="special">;</span>
|
||||
<span class="identifier">assert</span> <span class="special">(</span> <span class="special">**</span><span class="identifier">init2</span> <span class="special">==</span> <span class="number">3</span> <span class="special">)</span> <span class="special">;</span>
|
||||
</pre>
|
||||
</li>
|
||||
</ul></div>
|
||||
<p>
|
||||
<span class="inlinemediaobject"><img src="../images/space.png" alt="space"></span>
|
||||
</p>
|
||||
@ -368,6 +531,52 @@
|
||||
</pre>
|
||||
</li>
|
||||
</ul></div>
|
||||
<p>
|
||||
<span class="inlinemediaobject"><img src="../images/space.png" alt="space"></span>
|
||||
</p>
|
||||
<a name="reference_optional_move_constructor_other_optional"></a><div class="blockquote"><blockquote class="blockquote"><p>
|
||||
<code class="computeroutput"><span class="keyword">template</span><span class="special"><</span><span class="identifier">U</span><span class="special">></span> <span class="keyword">explicit</span> <span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span></code>
|
||||
<span class="emphasis"><em>(not a ref)</em></span><code class="computeroutput"><span class="special">>::</span><span class="identifier">optional</span><span class="special">(</span> <span class="identifier">optional</span><span class="special"><</span><span class="identifier">U</span><span class="special">>&&</span>
|
||||
<span class="identifier">rhs</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>Effect:</strong></span> Move-constructs an <code class="computeroutput"><span class="identifier">optional</span></code>.
|
||||
</li>
|
||||
<li class="listitem">
|
||||
<span class="bold"><strong>Postconditions:</strong></span> If <code class="computeroutput"><span class="identifier">rhs</span></code>
|
||||
is initialized, <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
|
||||
is initialized and its value is move constructed from <code class="computeroutput"><span class="special">*</span><span class="identifier">rhs</span></code>; else <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> is uninitialized.
|
||||
</li>
|
||||
<li class="listitem">
|
||||
<span class="bold"><strong>Throws:</strong></span> Whatever <code class="computeroutput"><span class="identifier">T</span><span class="special">::</span><span class="identifier">T</span><span class="special">(</span>
|
||||
<span class="identifier">U</span><span class="special">&&</span>
|
||||
<span class="special">)</span></code> throws.
|
||||
</li>
|
||||
<li class="listitem">
|
||||
<span class="bold"><strong>Notes: </strong></span> <code class="computeroutput"><span class="identifier">T</span><span class="special">::</span><span class="identifier">T</span><span class="special">(</span>
|
||||
<span class="identifier">U</span><span class="special">&&</span>
|
||||
<span class="special">)</span></code> is called if <code class="computeroutput"><span class="identifier">rhs</span></code>
|
||||
is initialized, which requires a valid conversion from <code class="computeroutput"><span class="identifier">U</span></code>
|
||||
to <code class="computeroutput"><span class="identifier">T</span></code>.
|
||||
</li>
|
||||
<li class="listitem">
|
||||
<span class="bold"><strong>Exception Safety:</strong></span> Exceptions can only
|
||||
be thrown during <code class="computeroutput"><span class="identifier">T</span><span class="special">::</span><span class="identifier">T</span><span class="special">(</span> <span class="identifier">U</span><span class="special">&&</span> <span class="special">);</span></code>
|
||||
in that case, <code class="computeroutput"><span class="identifier">rhs</span></code> remains
|
||||
initialized and the value of <code class="computeroutput"><span class="special">*</span><span class="identifier">rhs</span></code> is determined by exception safety
|
||||
guarantee of <code class="computeroutput"><span class="identifier">T</span><span class="special">::</span><span class="identifier">T</span><span class="special">(</span> <span class="identifier">U</span><span class="special">&&</span> <span class="special">)</span></code>.
|
||||
</li>
|
||||
<li class="listitem">
|
||||
<span class="bold"><strong>Example:</strong></span>
|
||||
<pre class="programlisting"><span class="identifier">optional</span><span class="special"><</span><span class="keyword">double</span><span class="special">></span> <span class="identifier">x</span><span class="special">(</span><span class="number">123.4</span><span class="special">);</span>
|
||||
<span class="identifier">assert</span> <span class="special">(</span> <span class="special">*</span><span class="identifier">x</span> <span class="special">==</span> <span class="number">123.4</span> <span class="special">)</span> <span class="special">;</span>
|
||||
|
||||
<span class="identifier">optional</span><span class="special"><</span><span class="keyword">int</span><span class="special">></span> <span class="identifier">y</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">x</span><span class="special">))</span> <span class="special">;</span>
|
||||
<span class="identifier">assert</span><span class="special">(</span> <span class="special">*</span><span class="identifier">y</span> <span class="special">==</span> <span class="number">123</span> <span class="special">)</span> <span class="special">;</span>
|
||||
</pre>
|
||||
</li>
|
||||
</ul></div>
|
||||
<p>
|
||||
<span class="inlinemediaobject"><img src="../images/space.png" alt="space"></span>
|
||||
</p>
|
||||
@ -511,6 +720,66 @@
|
||||
</pre>
|
||||
</li>
|
||||
</ul></div>
|
||||
<p>
|
||||
<span class="inlinemediaobject"><img src="../images/space.png" alt="space"></span>
|
||||
</p>
|
||||
<a name="reference_optional_operator_move_equal_value"></a><div class="blockquote"><blockquote class="blockquote"><p>
|
||||
<code class="computeroutput"><span class="identifier">optional</span><span class="special">&</span>
|
||||
<span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span></code> <span class="emphasis"><em>(not a ref)</em></span><code class="computeroutput"><span class="special">>::</span><span class="keyword">operator</span><span class="special">=</span> <span class="special">(</span> <span class="identifier">T</span><span class="special">&&</span> <span class="identifier">rhs</span>
|
||||
<span class="special">)</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>Effect:</strong></span> Moves the value <code class="computeroutput"><span class="identifier">rhs</span></code> to an <code class="computeroutput"><span class="identifier">optional</span></code>.
|
||||
</li>
|
||||
<li class="listitem">
|
||||
<span class="bold"><strong>Postconditions: </strong></span> <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> is initialized and its value is moved
|
||||
from <code class="computeroutput"><span class="identifier">rhs</span></code>.
|
||||
</li>
|
||||
<li class="listitem">
|
||||
<span class="bold"><strong>Throws:</strong></span> Whatever <code class="computeroutput"><span class="identifier">T</span><span class="special">::</span><span class="keyword">operator</span><span class="special">=(</span> <span class="identifier">T</span><span class="special">&&</span> <span class="special">)</span></code>
|
||||
or <code class="computeroutput"><span class="identifier">T</span><span class="special">::</span><span class="identifier">T</span><span class="special">(</span><span class="identifier">T</span>
|
||||
<span class="special">&&)</span></code> throws.
|
||||
</li>
|
||||
<li class="listitem">
|
||||
<span class="bold"><strong>Notes:</strong></span> If <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> was initialized, <code class="computeroutput"><span class="identifier">T</span></code>'s
|
||||
move-assignment operator is used, otherwise, its move-constructor is used.
|
||||
</li>
|
||||
<li class="listitem">
|
||||
<span class="bold"><strong>Exception Safety:</strong></span> In the event of an exception,
|
||||
the initialization state of <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> is unchanged and its value unspecified
|
||||
as far as <code class="computeroutput"><span class="identifier">optional</span></code> is concerned
|
||||
(it is up to <code class="computeroutput"><span class="identifier">T</span></code>'s <code class="computeroutput"><span class="keyword">operator</span><span class="special">=()</span></code>).
|
||||
If <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
|
||||
is initially uninitialized and <code class="computeroutput"><span class="identifier">T</span></code>'s
|
||||
<span class="emphasis"><em>move constructor</em></span> fails, <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> is left properly uninitialized.
|
||||
</li>
|
||||
<li class="listitem">
|
||||
<span class="bold"><strong>Example:</strong></span>
|
||||
<pre class="programlisting"><span class="identifier">T</span> <span class="identifier">x</span><span class="special">;</span>
|
||||
<span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">></span> <span class="identifier">def</span> <span class="special">;</span>
|
||||
<span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">></span> <span class="identifier">opt</span><span class="special">(</span><span class="identifier">x</span><span class="special">)</span> <span class="special">;</span>
|
||||
|
||||
<span class="identifier">T</span> <span class="identifier">y1</span><span class="special">,</span> <span class="identifier">y2</span><span class="special">,</span> <span class="identifier">yR</span><span class="special">;</span>
|
||||
<span class="identifier">def</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">y1</span><span class="special">)</span> <span class="special">;</span>
|
||||
<span class="identifier">assert</span> <span class="special">(</span> <span class="special">*</span><span class="identifier">def</span> <span class="special">==</span> <span class="identifier">yR</span> <span class="special">)</span> <span class="special">;</span>
|
||||
<span class="identifier">opt</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">y2</span><span class="special">)</span> <span class="special">;</span>
|
||||
<span class="identifier">assert</span> <span class="special">(</span> <span class="special">*</span><span class="identifier">opt</span> <span class="special">==</span> <span class="identifier">yR</span> <span class="special">)</span> <span class="special">;</span>
|
||||
</pre>
|
||||
</li>
|
||||
</ul></div>
|
||||
<p>
|
||||
<span class="inlinemediaobject"><img src="../images/space.png" alt="space"></span>
|
||||
</p>
|
||||
<div class="blockquote"><blockquote class="blockquote"><p>
|
||||
<code class="computeroutput"><span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">&>&</span>
|
||||
<span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">&>::</span><span class="keyword">operator</span><span class="special">=</span> <span class="special">(</span> <span class="identifier">T</span><span class="special">&&</span>
|
||||
<span class="identifier">rhs</span> <span class="special">)</span>
|
||||
<span class="special">=</span> <span class="keyword">delete</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>Notes:</strong></span> This assignment operator is deleted.
|
||||
</li></ul></div>
|
||||
<p>
|
||||
<span class="inlinemediaobject"><img src="../images/space.png" alt="space"></span>
|
||||
</p>
|
||||
@ -613,6 +882,75 @@
|
||||
</pre>
|
||||
</li>
|
||||
</ul></div>
|
||||
<p>
|
||||
<span class="inlinemediaobject"><img src="../images/space.png" alt="space"></span>
|
||||
</p>
|
||||
<a name="reference_optional_operator_move_equal_optional"></a><div class="blockquote"><blockquote class="blockquote"><p>
|
||||
<code class="computeroutput"><span class="identifier">optional</span><span class="special">&</span>
|
||||
<span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span></code> <span class="emphasis"><em>(not a ref)</em></span><code class="computeroutput"><span class="special">>::</span><span class="keyword">operator</span><span class="special">=</span> <span class="special">(</span> <span class="identifier">optional</span><span class="special">&&</span> <span class="identifier">rhs</span>
|
||||
<span class="special">)</span> <span class="keyword">noexcept</span><span class="special">(</span></code><span class="emphasis"><em>see below</em></span><code class="computeroutput"><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>Effect:</strong></span> Move-assigns another <code class="computeroutput"><span class="identifier">optional</span></code> to an <code class="computeroutput"><span class="identifier">optional</span></code>.
|
||||
</li>
|
||||
<li class="listitem">
|
||||
<span class="bold"><strong>Postconditions:</strong></span> If <code class="computeroutput"><span class="identifier">rhs</span></code>
|
||||
is initialized, <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
|
||||
is initialized and its value is moved from <code class="computeroutput"><span class="special">*</span><span class="identifier">rhs</span></code>, <code class="computeroutput"><span class="identifier">rhs</span></code>
|
||||
remains initialized; else <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> is uninitialized.
|
||||
</li>
|
||||
<li class="listitem">
|
||||
<span class="bold"><strong>Throws:</strong></span> Whatever <code class="computeroutput"><span class="identifier">T</span><span class="special">::</span><span class="keyword">operator</span><span class="special">(</span> <span class="identifier">T</span><span class="special">&&</span>
|
||||
<span class="special">)</span></code> or <code class="computeroutput"><span class="identifier">T</span><span class="special">::</span><span class="identifier">T</span><span class="special">(</span>
|
||||
<span class="identifier">T</span> <span class="special">&&</span>
|
||||
<span class="special">)</span></code> throws.
|
||||
</li>
|
||||
<li class="listitem">
|
||||
<span class="bold"><strong>Notes:</strong></span> If both <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> and <code class="computeroutput"><span class="identifier">rhs</span></code>
|
||||
are initially initialized, <code class="computeroutput"><span class="identifier">T</span></code>'s
|
||||
<span class="emphasis"><em>move assignment operator</em></span> is used. If <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> is
|
||||
initially initialized but <code class="computeroutput"><span class="identifier">rhs</span></code>
|
||||
is uninitialized, <code class="computeroutput"><span class="identifier">T</span></code>'s [destructor]
|
||||
is called. If <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
|
||||
is initially uninitialized but <code class="computeroutput"><span class="identifier">rhs</span></code>
|
||||
is initialized, <code class="computeroutput"><span class="identifier">T</span></code>'s <span class="emphasis"><em>move
|
||||
constructor</em></span> is called. The expression inside <code class="computeroutput"><span class="keyword">noexcept</span></code>
|
||||
is equivalent to <code class="computeroutput"><span class="identifier">is_nothrow_move_constructible</span><span class="special"><</span><span class="identifier">T</span><span class="special">>::</span><span class="identifier">value</span>
|
||||
<span class="special">&&</span> <span class="identifier">is_nothrow_move_assignable</span><span class="special"><</span><span class="identifier">T</span><span class="special">>::</span><span class="identifier">value</span></code>.
|
||||
</li>
|
||||
<li class="listitem">
|
||||
<span class="bold"><strong>Exception Safety:</strong></span> In the event of an exception,
|
||||
the initialization state of <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> is unchanged and its value unspecified
|
||||
as far as optional is concerned (it is up to <code class="computeroutput"><span class="identifier">T</span></code>'s
|
||||
<code class="computeroutput"><span class="keyword">operator</span><span class="special">=()</span></code>).
|
||||
If <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
|
||||
is initially uninitialized and <code class="computeroutput"><span class="identifier">T</span></code>'s
|
||||
<span class="emphasis"><em>move constructor</em></span> fails, <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> is left properly uninitialized.
|
||||
</li>
|
||||
<li class="listitem">
|
||||
<span class="bold"><strong>Example:</strong></span>
|
||||
<pre class="programlisting"><span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">></span> <span class="identifier">opt</span><span class="special">(</span><span class="identifier">T</span><span class="special">(</span><span class="number">2</span><span class="special">))</span> <span class="special">;</span>
|
||||
<span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">></span> <span class="identifier">def</span> <span class="special">;</span>
|
||||
|
||||
<span class="identifier">opt</span> <span class="special">=</span> <span class="identifier">def</span> <span class="special">;</span>
|
||||
<span class="identifier">assert</span> <span class="special">(</span> <span class="identifier">def</span> <span class="special">)</span> <span class="special">;</span>
|
||||
<span class="identifier">assert</span> <span class="special">(</span> <span class="identifier">opt</span> <span class="special">)</span> <span class="special">;</span>
|
||||
<span class="identifier">assert</span> <span class="special">(</span> <span class="special">*</span><span class="identifier">opt</span> <span class="special">==</span> <span class="identifier">T</span><span class="special">(</span><span class="number">2</span><span class="special">)</span> <span class="special">)</span> <span class="special">;</span>
|
||||
</pre>
|
||||
</li>
|
||||
</ul></div>
|
||||
<p>
|
||||
<span class="inlinemediaobject"><img src="../images/space.png" alt="space"></span>
|
||||
</p>
|
||||
<div class="blockquote"><blockquote class="blockquote"><p>
|
||||
<code class="computeroutput"><span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">&></span> <span class="special">&</span> <span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">&>::</span><span class="keyword">operator</span><span class="special">=</span> <span class="special">(</span> <span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">&>&&</span>
|
||||
<span class="identifier">rhs</span> <span class="special">)</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>Effect:</strong></span> Same as <code class="computeroutput"><span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">&>::</span><span class="keyword">operator</span><span class="special">=</span> <span class="special">(</span> <span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">&></span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">rhs</span> <span class="special">)</span></code>.
|
||||
</li></ul></div>
|
||||
<p>
|
||||
<span class="inlinemediaobject"><img src="../images/space.png" alt="space"></span>
|
||||
</p>
|
||||
@ -673,6 +1011,59 @@
|
||||
</pre>
|
||||
</li>
|
||||
</ul></div>
|
||||
<p>
|
||||
<span class="inlinemediaobject"><img src="../images/space.png" alt="space"></span>
|
||||
</p>
|
||||
<a name="reference_optional_operator_move_equal_other_optional"></a><div class="blockquote"><blockquote class="blockquote"><p>
|
||||
<code class="computeroutput"><span class="keyword">template</span><span class="special"><</span><span class="identifier">U</span><span class="special">></span> <span class="identifier">optional</span><span class="special">&</span>
|
||||
<span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span></code> <span class="emphasis"><em>(not a ref)</em></span><code class="computeroutput"><span class="special">>::</span><span class="keyword">operator</span><span class="special">=</span> <span class="special">(</span> <span class="identifier">optional</span><span class="special"><</span><span class="identifier">U</span><span class="special">>&&</span>
|
||||
<span class="identifier">rhs</span> <span class="special">)</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>Effect:</strong></span> Move-assigns another convertible
|
||||
optional to an optional.
|
||||
</li>
|
||||
<li class="listitem">
|
||||
<span class="bold"><strong>Postconditions:</strong></span> If <code class="computeroutput"><span class="identifier">rhs</span></code>
|
||||
is initialized, <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
|
||||
is initialized and its value is moved from the value of <code class="computeroutput"><span class="identifier">rhs</span></code>;
|
||||
else <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
|
||||
is uninitialized.
|
||||
</li>
|
||||
<li class="listitem">
|
||||
<span class="bold"><strong>Throws:</strong></span> Whatever <code class="computeroutput"><span class="identifier">T</span><span class="special">::</span><span class="keyword">operator</span><span class="special">=(</span> <span class="identifier">U</span><span class="special">&&</span> <span class="special">)</span></code>
|
||||
or <code class="computeroutput"><span class="identifier">T</span><span class="special">::</span><span class="identifier">T</span><span class="special">(</span> <span class="identifier">U</span><span class="special">&&</span> <span class="special">)</span></code>
|
||||
throws.
|
||||
</li>
|
||||
<li class="listitem">
|
||||
<span class="bold"><strong>Notes:</strong></span> If both <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> and <code class="computeroutput"><span class="identifier">rhs</span></code>
|
||||
are initially initialized, <code class="computeroutput"><span class="identifier">T</span></code>'s
|
||||
<span class="emphasis"><em>assignment operator</em></span> (from <code class="computeroutput"><span class="identifier">U</span><span class="special">&&</span></code>) is used. If <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> is initially initialized but <code class="computeroutput"><span class="identifier">rhs</span></code> is uninitialized, <code class="computeroutput"><span class="identifier">T</span></code>'s
|
||||
<span class="emphasis"><em>destructor</em></span> is called. If <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> is initially uninitialized but <code class="computeroutput"><span class="identifier">rhs</span></code> is initialized, <code class="computeroutput"><span class="identifier">T</span></code>'s
|
||||
<span class="emphasis"><em>converting constructor</em></span> (from <code class="computeroutput"><span class="identifier">U</span><span class="special">&&</span></code>) is called.
|
||||
</li>
|
||||
<li class="listitem">
|
||||
<span class="bold"><strong>Exception Safety:</strong></span> In the event of an exception,
|
||||
the initialization state of <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> is unchanged and its value unspecified
|
||||
as far as optional is concerned (it is up to <code class="computeroutput"><span class="identifier">T</span></code>'s
|
||||
<code class="computeroutput"><span class="keyword">operator</span><span class="special">=()</span></code>).
|
||||
If <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
|
||||
is initially uninitialized and <code class="computeroutput"><span class="identifier">T</span></code>'s
|
||||
converting constructor fails, <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> is left properly uninitialized.
|
||||
</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"><</span><span class="identifier">T</span><span class="special">></span> <span class="identifier">opt0</span><span class="special">(</span><span class="identifier">v</span><span class="special">);</span>
|
||||
<span class="identifier">optional</span><span class="special"><</span><span class="identifier">U</span><span class="special">></span> <span class="identifier">opt1</span><span class="special">;</span>
|
||||
|
||||
<span class="identifier">opt1</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">opt0</span><span class="special">)</span> <span class="special">;</span>
|
||||
<span class="identifier">assert</span> <span class="special">(</span> <span class="special">*</span><span class="identifier">opt1</span> <span class="special">==</span> <span class="keyword">static_cast</span><span class="special"><</span><span class="identifier">U</span><span class="special">>(</span><span class="identifier">v</span><span class="special">)</span> <span class="special">)</span> <span class="special">;</span>
|
||||
</pre>
|
||||
</li>
|
||||
</ul></div>
|
||||
<p>
|
||||
<span class="inlinemediaobject"><img src="../images/space.png" alt="space"></span>
|
||||
</p>
|
||||
@ -768,7 +1159,7 @@
|
||||
</p></blockquote></div>
|
||||
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
|
||||
<li class="listitem">
|
||||
<span class="bold"><strong>Requirements:</strong></span> <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> is initialized
|
||||
<span class="bold"><strong>Requires:</strong></span> <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> is initialized
|
||||
</li>
|
||||
<li class="listitem">
|
||||
<span class="bold"><strong>Returns:</strong></span> A reference to the contained
|
||||
@ -870,7 +1261,7 @@
|
||||
</p></blockquote></div>
|
||||
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
|
||||
<li class="listitem">
|
||||
<span class="bold"><strong>Requirements: </strong></span> <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> is initialized
|
||||
<span class="bold"><strong>Requires: </strong></span> <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> is initialized
|
||||
</li>
|
||||
<li class="listitem">
|
||||
<span class="bold"><strong>Returns:</strong></span> <span class="underline">The</span>
|
||||
@ -956,7 +1347,7 @@
|
||||
</p></blockquote></div>
|
||||
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
|
||||
<li class="listitem">
|
||||
<span class="bold"><strong>Requirements: </strong></span> <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> is initialized.
|
||||
<span class="bold"><strong>Requires: </strong></span> <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> is initialized.
|
||||
</li>
|
||||
<li class="listitem">
|
||||
<span class="bold"><strong>Returns:</strong></span> A pointer to the contained value.
|
||||
@ -1005,16 +1396,13 @@
|
||||
<span class="inlinemediaobject"><img src="../images/space.png" alt="space"></span>
|
||||
</p>
|
||||
<a name="reference_optional_operator_not"></a><div class="blockquote"><blockquote class="blockquote"><p>
|
||||
<code class="computeroutput"><span class="keyword">bool</span> <span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">>::</span><span class="keyword">operator</span><span class="special">!()</span> <span class="special">;</span></code>
|
||||
<code class="computeroutput"><span class="keyword">bool</span> <span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">>::</span><span class="keyword">operator</span><span class="special">!()</span> <span class="keyword">noexcept</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>Returns:</strong></span> If <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> is uninitialized, <code class="computeroutput"><span class="keyword">true</span></code>;
|
||||
else <code class="computeroutput"><span class="keyword">false</span></code>.
|
||||
</li>
|
||||
<li class="listitem">
|
||||
<span class="bold"><strong>Throws:</strong></span> Nothing.
|
||||
</li>
|
||||
<li class="listitem">
|
||||
<span class="bold"><strong>Notes:</strong></span> This operator is provided for those
|
||||
compilers which can't use the <span class="emphasis"><em>unspecified-bool-type operator</em></span>
|
||||
@ -1288,7 +1676,7 @@
|
||||
<a name="reference_swap_optional_optional"></a><div class="blockquote"><blockquote class="blockquote"><p>
|
||||
<code class="computeroutput"><span class="keyword">void</span> <span class="identifier">swap</span>
|
||||
<span class="special">(</span> <span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">>&</span>
|
||||
<span class="identifier">x</span><span class="special">,</span> <span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">>&</span> <span class="identifier">y</span> <span class="special">);</span></code>
|
||||
<span class="identifier">x</span><span class="special">,</span> <span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">>&</span> <span class="identifier">y</span> <span class="special">)</span> <span class="special">;</span></code>
|
||||
</p></blockquote></div>
|
||||
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
|
||||
<li class="listitem">
|
||||
@ -1305,19 +1693,21 @@
|
||||
<li class="listitem">
|
||||
<span class="bold"><strong>Throws:</strong></span> If both are initialized, whatever
|
||||
<code class="computeroutput"><span class="identifier">swap</span><span class="special">(</span><span class="identifier">T</span><span class="special">&,</span><span class="identifier">T</span><span class="special">&)</span></code>
|
||||
throws. If only one is initialized, whatever <code class="computeroutput"><span class="identifier">T</span><span class="special">::</span><span class="identifier">T</span> <span class="special">(</span> <span class="identifier">T</span> <span class="keyword">const</span><span class="special">&</span> <span class="special">)</span></code> throws.
|
||||
throws. If only one is initialized, whatever <code class="computeroutput"><span class="identifier">T</span><span class="special">::</span><span class="identifier">T</span> <span class="special">(</span> <span class="identifier">T</span><span class="special">&&</span>
|
||||
<span class="special">)</span></code> throws.
|
||||
</li>
|
||||
<li class="listitem">
|
||||
<span class="bold"><strong>Notes:</strong></span> If both are initialized, <code class="computeroutput"><span class="identifier">swap</span><span class="special">(</span><span class="identifier">T</span><span class="special">&,</span><span class="identifier">T</span><span class="special">&)</span></code>
|
||||
is used unqualified but with <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">swap</span></code>
|
||||
introduced in scope. If only one is initialized, <code class="computeroutput"><span class="identifier">T</span><span class="special">::~</span><span class="identifier">T</span><span class="special">()</span></code> and <code class="computeroutput"><span class="identifier">T</span><span class="special">::</span><span class="identifier">T</span><span class="special">(</span>
|
||||
<span class="identifier">T</span> <span class="keyword">const</span><span class="special">&</span> <span class="special">)</span></code>
|
||||
is called.
|
||||
<span class="identifier">T</span><span class="special">&&</span>
|
||||
<span class="special">)</span></code> is called.
|
||||
</li>
|
||||
<li class="listitem">
|
||||
<span class="bold"><strong>Exception Safety:</strong></span> If both are initialized,
|
||||
this operation has the exception safety guarantees of <code class="computeroutput"><span class="identifier">swap</span><span class="special">(</span><span class="identifier">T</span><span class="special">&,</span><span class="identifier">T</span><span class="special">&)</span></code>.
|
||||
If only one is initialized, it has the same basic guarantee as <code class="computeroutput"><span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">>::</span><span class="identifier">reset</span><span class="special">(</span> <span class="identifier">T</span> <span class="keyword">const</span><span class="special">&</span> <span class="special">)</span></code>.
|
||||
If only one is initialized, it has the same basic guarantee as <code class="computeroutput"><span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">>::</span><span class="keyword">operator</span><span class="special">=</span> <span class="special">(</span> <span class="identifier">T</span><span class="special">&&</span>
|
||||
<span class="special">)</span></code>.
|
||||
</li>
|
||||
<li class="listitem">
|
||||
<span class="bold"><strong>Example:</strong></span>
|
||||
|
||||
@ -68,6 +68,22 @@
|
||||
than the reference itself.
|
||||
</li>
|
||||
</ul></div>
|
||||
<h4>
|
||||
<a name="boost_optional.optional_references.h0"></a>
|
||||
<span class="phrase"><a name="boost_optional.optional_references.rvalue_references"></a></span><a class="link" href="optional_references.html#boost_optional.optional_references.rvalue_references">Rvalue
|
||||
references</a>
|
||||
</h4>
|
||||
<p>
|
||||
Rvalue references and lvalue references to const have the ability in C++ to
|
||||
extend the life time of a temporary they bind to. Optional references do not
|
||||
have this capability, therefore to avoid surprising effects it is not possible
|
||||
to initialize an optional references from a temporary. Optional rvalue references
|
||||
are disabled altogether. Also, the initialization and assignment of an optional
|
||||
reference to const from rvalue reference is disabled.
|
||||
</p>
|
||||
<pre class="programlisting"><span class="keyword">const</span> <span class="keyword">int</span><span class="special">&</span> <span class="identifier">i</span> <span class="special">=</span> <span class="number">1</span><span class="special">;</span> <span class="comment">// legal</span>
|
||||
<span class="identifier">optional</span><span class="special"><</span><span class="keyword">const</span> <span class="keyword">int</span><span class="special">&></span> <span class="identifier">oi</span> <span class="special">=</span> <span class="number">1</span><span class="special">;</span> <span class="comment">// illegal</span>
|
||||
</pre>
|
||||
</div>
|
||||
<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
|
||||
<td align="left"></td>
|
||||
|
||||
@ -37,19 +37,25 @@
|
||||
|
||||
<span class="comment">// (If T is of reference type, the parameters and results by reference are by value)</span>
|
||||
|
||||
<span class="identifier">optional</span> <span class="special">()</span> <span class="special">;</span> <a class="link" href="detailed_semantics.html#reference_optional_constructor"><span class="inlinemediaobject"><img src="../images/callouts/R.png" alt="R"></span></a>
|
||||
<span class="identifier">optional</span> <span class="special">()</span> <span class="keyword">noexcept</span> <span class="special">;</span> <a class="link" href="detailed_semantics.html#reference_optional_constructor"><span class="inlinemediaobject"><img src="../images/callouts/R.png" alt="R"></span></a>
|
||||
|
||||
<span class="identifier">optional</span> <span class="special">(</span> <span class="identifier">none_t</span> <span class="special">)</span> <span class="special">;</span> <a class="link" href="detailed_semantics.html#reference_optional_constructor_none_t"><span class="inlinemediaobject"><img src="../images/callouts/R.png" alt="R"></span></a>
|
||||
<span class="identifier">optional</span> <span class="special">(</span> <span class="identifier">none_t</span> <span class="special">)</span> <span class="keyword">noexcept</span> <span class="special">;</span> <a class="link" href="detailed_semantics.html#reference_optional_constructor_none_t"><span class="inlinemediaobject"><img src="../images/callouts/R.png" alt="R"></span></a>
|
||||
|
||||
<span class="identifier">optional</span> <span class="special">(</span> <span class="identifier">T</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">v</span> <span class="special">)</span> <span class="special">;</span> <a class="link" href="detailed_semantics.html#reference_optional_constructor_value"><span class="inlinemediaobject"><img src="../images/callouts/R.png" alt="R"></span></a>
|
||||
|
||||
<span class="identifier">optional</span> <span class="special">(</span> <span class="identifier">T</span><span class="special">&&</span> <span class="identifier">v</span> <span class="special">)</span> <span class="special">;</span> <a class="link" href="detailed_semantics.html#reference_optional_constructor_move_value"><span class="inlinemediaobject"><img src="../images/callouts/R.png" alt="R"></span></a>
|
||||
|
||||
<span class="comment">// [new in 1.34]</span>
|
||||
<span class="identifier">optional</span> <span class="special">(</span> <span class="keyword">bool</span> <span class="identifier">condition</span><span class="special">,</span> <span class="identifier">T</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">v</span> <span class="special">)</span> <span class="special">;</span> <a class="link" href="detailed_semantics.html#reference_optional_constructor_bool_value"><span class="inlinemediaobject"><img src="../images/callouts/R.png" alt="R"></span></a>
|
||||
|
||||
<span class="identifier">optional</span> <span class="special">(</span> <span class="identifier">optional</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">rhs</span> <span class="special">)</span> <span class="special">;</span> <a class="link" href="detailed_semantics.html#reference_optional_constructor_optional"><span class="inlinemediaobject"><img src="../images/callouts/R.png" alt="R"></span></a>
|
||||
|
||||
<span class="identifier">optional</span> <span class="special">(</span> <span class="identifier">optional</span><span class="special">&&</span> <span class="identifier">rhs</span> <span class="special">)</span> <span class="keyword">noexcept</span><span class="special">(</span><span class="emphasis"><em>see below</em></span><span class="special">)</span> <span class="special">;</span> <a class="link" href="detailed_semantics.html#reference_optional_move_constructor_optional"><span class="inlinemediaobject"><img src="../images/callouts/R.png" alt="R"></span></a>
|
||||
|
||||
<span class="keyword">template</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">U</span><span class="special">></span> <span class="keyword">explicit</span> <span class="identifier">optional</span> <span class="special">(</span> <span class="identifier">optional</span><span class="special"><</span><span class="identifier">U</span><span class="special">></span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">rhs</span> <span class="special">)</span> <span class="special">;</span> <a class="link" href="detailed_semantics.html#reference_optional_constructor_other_optional"><span class="inlinemediaobject"><img src="../images/callouts/R.png" alt="R"></span></a>
|
||||
|
||||
<span class="keyword">template</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">U</span><span class="special">></span> <span class="keyword">explicit</span> <span class="identifier">optional</span> <span class="special">(</span> <span class="identifier">optional</span><span class="special"><</span><span class="identifier">U</span><span class="special">>&&</span> <span class="identifier">rhs</span> <span class="special">)</span> <span class="special">;</span> <a class="link" href="detailed_semantics.html#reference_optional_move_constructor_other_optional"><span class="inlinemediaobject"><img src="../images/callouts/R.png" alt="R"></span></a>
|
||||
|
||||
<span class="keyword">template</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">InPlaceFactory</span><span class="special">></span> <span class="keyword">explicit</span> <span class="identifier">optional</span> <span class="special">(</span> <span class="identifier">InPlaceFactory</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">f</span> <span class="special">)</span> <span class="special">;</span> <a class="link" href="detailed_semantics.html#reference_optional_constructor_factory"><span class="inlinemediaobject"><img src="../images/callouts/R.png" alt="R"></span></a>
|
||||
|
||||
<span class="keyword">template</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">TypedInPlaceFactory</span><span class="special">></span> <span class="keyword">explicit</span> <span class="identifier">optional</span> <span class="special">(</span> <span class="identifier">TypedInPlaceFactory</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">f</span> <span class="special">)</span> <span class="special">;</span> <a class="link" href="detailed_semantics.html#reference_optional_constructor_factory"><span class="inlinemediaobject"><img src="../images/callouts/R.png" alt="R"></span></a>
|
||||
@ -58,10 +64,16 @@
|
||||
|
||||
<span class="identifier">optional</span><span class="special">&</span> <span class="keyword">operator</span> <span class="special">=</span> <span class="special">(</span> <span class="identifier">T</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">v</span> <span class="special">)</span> <span class="special">;</span> <a class="link" href="detailed_semantics.html#reference_optional_operator_equal_value"><span class="inlinemediaobject"><img src="../images/callouts/R.png" alt="R"></span></a>
|
||||
|
||||
<span class="identifier">optional</span><span class="special">&</span> <span class="keyword">operator</span> <span class="special">=</span> <span class="special">(</span> <span class="identifier">T</span><span class="special">&&</span> <span class="identifier">v</span> <span class="special">)</span> <span class="special">;</span> <a class="link" href="detailed_semantics.html#reference_optional_operator_move_equal_value"><span class="inlinemediaobject"><img src="../images/callouts/R.png" alt="R"></span></a>
|
||||
|
||||
<span class="identifier">optional</span><span class="special">&</span> <span class="keyword">operator</span> <span class="special">=</span> <span class="special">(</span> <span class="identifier">optional</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">rhs</span> <span class="special">)</span> <span class="special">;</span> <a class="link" href="detailed_semantics.html#reference_optional_operator_equal_optional"><span class="inlinemediaobject"><img src="../images/callouts/R.png" alt="R"></span></a>
|
||||
|
||||
<span class="identifier">optional</span><span class="special">&</span> <span class="keyword">operator</span> <span class="special">=</span> <span class="special">(</span> <span class="identifier">optional</span><span class="special">&&</span> <span class="identifier">rhs</span> <span class="special">)</span> <span class="keyword">noexcept</span><span class="special">(</span><span class="emphasis"><em>see below</em></span><span class="special">)</span> <span class="special">;</span> <a class="link" href="detailed_semantics.html#reference_optional_operator_move_equal_optional"><span class="inlinemediaobject"><img src="../images/callouts/R.png" alt="R"></span></a>
|
||||
|
||||
<span class="keyword">template</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">U</span><span class="special">></span> <span class="identifier">optional</span><span class="special">&</span> <span class="keyword">operator</span> <span class="special">=</span> <span class="special">(</span> <span class="identifier">optional</span><span class="special"><</span><span class="identifier">U</span><span class="special">></span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">rhs</span> <span class="special">)</span> <span class="special">;</span> <a class="link" href="detailed_semantics.html#reference_optional_operator_equal_other_optional"><span class="inlinemediaobject"><img src="../images/callouts/R.png" alt="R"></span></a>
|
||||
|
||||
<span class="keyword">template</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">U</span><span class="special">></span> <span class="identifier">optional</span><span class="special">&</span> <span class="keyword">operator</span> <span class="special">=</span> <span class="special">(</span> <span class="identifier">optional</span><span class="special"><</span><span class="identifier">U</span><span class="special">>&&</span> <span class="identifier">rhs</span> <span class="special">)</span> <span class="special">;</span> <a class="link" href="detailed_semantics.html#reference_optional_operator_move_equal_other_optional"><span class="inlinemediaobject"><img src="../images/callouts/R.png" alt="R"></span></a>
|
||||
|
||||
<span class="keyword">template</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">InPlaceFactory</span><span class="special">></span> <span class="identifier">optional</span><span class="special">&</span> <span class="keyword">operator</span> <span class="special">=</span> <span class="special">(</span> <span class="identifier">InPlaceFactory</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">f</span> <span class="special">)</span> <span class="special">;</span> <a class="link" href="detailed_semantics.html#reference_optional_operator_equal_factory"><span class="inlinemediaobject"><img src="../images/callouts/R.png" alt="R"></span></a>
|
||||
|
||||
<span class="keyword">template</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">TypedInPlaceFactory</span><span class="special">></span> <span class="identifier">optional</span><span class="special">&</span> <span class="keyword">operator</span> <span class="special">=</span> <span class="special">(</span> <span class="identifier">TypedInPlaceFactory</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">f</span> <span class="special">)</span> <span class="special">;</span> <a class="link" href="detailed_semantics.html#reference_optional_operator_equal_factory"><span class="inlinemediaobject"><img src="../images/callouts/R.png" alt="R"></span></a>
|
||||
@ -83,7 +95,7 @@
|
||||
|
||||
<span class="keyword">operator</span> <span class="identifier">unspecified</span><span class="special">-</span><span class="keyword">bool</span><span class="special">-</span><span class="identifier">type</span><span class="special">()</span> <span class="keyword">const</span> <span class="special">;</span> <a class="link" href="detailed_semantics.html#reference_optional_operator_bool"><span class="inlinemediaobject"><img src="../images/callouts/R.png" alt="R"></span></a>
|
||||
|
||||
<span class="keyword">bool</span> <span class="keyword">operator</span><span class="special">!()</span> <span class="keyword">const</span> <span class="special">;</span> <a class="link" href="detailed_semantics.html#reference_optional_operator_not"><span class="inlinemediaobject"><img src="../images/callouts/R.png" alt="R"></span></a>
|
||||
<span class="keyword">bool</span> <span class="keyword">operator</span><span class="special">!()</span> <span class="keyword">const</span> <span class="keyword">noexcept</span> <span class="special">;</span> <a class="link" href="detailed_semantics.html#reference_optional_operator_not"><span class="inlinemediaobject"><img src="../images/callouts/R.png" alt="R"></span></a>
|
||||
|
||||
<span class="comment">// deprecated methods</span>
|
||||
|
||||
|
||||
Reference in New Issue
Block a user