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documented in-place constructors

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<div class="section">
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<a name="boost_optional.dependencies_and_portability.emplace_operations_in_older_compilers"></a><a class="link" href="emplace_operations_in_older_compilers.html" title="Emplace operations in older compilers">Emplace
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<p>
<a name="optional_emplace_workaround"></a>Certain constructors and functions
in the interface of <code class="computeroutput"><span class="identifier">optional</span></code>
perform a 'perfect forwarding' of arguments:
</p>
<pre class="programlisting"><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span><span class="special">...</span> <span class="identifier">Args</span><span class="special">&gt;</span> <span class="identifier">optional</span><span class="special">(</span><span class="identifier">in_place_init_t</span><span class="special">,</span> <span class="identifier">Args</span><span class="special">&amp;&amp;...</span> <span class="identifier">args</span><span class="special">);</span>
<span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span><span class="special">...</span> <span class="identifier">Args</span><span class="special">&gt;</span> <span class="identifier">optional</span><span class="special">(</span><span class="identifier">in_place_init_if_t</span><span class="special">,</span> <span class="keyword">bool</span> <span class="identifier">condition</span><span class="special">,</span> <span class="identifier">Args</span><span class="special">&amp;&amp;...</span> <span class="identifier">args</span><span class="special">);</span>
<span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span><span class="special">...</span> <span class="identifier">Args</span><span class="special">&gt;</span> <span class="keyword">void</span> <span class="identifier">emplace</span><span class="special">(</span><span class="identifier">Args</span><span class="special">&amp;&amp;...</span> <span class="identifier">args</span><span class="special">);</span>
</pre>
<p>
On compilers that do not support variadic templates, each of these functions
is substituted with two overloads, one forwarding a single argument, the
other forwarding zero arguments. This forms the following set:
</p>
<pre class="programlisting"><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">Arg</span><span class="special">&gt;</span> <span class="identifier">optional</span><span class="special">(</span><span class="identifier">in_place_init_t</span><span class="special">,</span> <span class="identifier">Arg</span><span class="special">&amp;&amp;</span> <span class="identifier">arg</span><span class="special">);</span>
<span class="identifier">optional</span><span class="special">(</span><span class="identifier">in_place_init_t</span><span class="special">);</span>
<span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">Arg</span><span class="special">&gt;</span> <span class="identifier">optional</span><span class="special">(</span><span class="identifier">in_place_init_if_t</span><span class="special">,</span> <span class="keyword">bool</span> <span class="identifier">condition</span><span class="special">,</span> <span class="identifier">Arg</span><span class="special">&amp;&amp;</span> <span class="identifier">arg</span><span class="special">);</span>
<span class="identifier">optional</span><span class="special">(</span><span class="identifier">in_place_init_if_t</span><span class="special">,</span> <span class="keyword">bool</span> <span class="identifier">condition</span><span class="special">);</span>
<span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">Arg</span><span class="special">&gt;</span> <span class="keyword">void</span> <span class="identifier">emplace</span><span class="special">(</span><span class="identifier">Arg</span><span class="special">&amp;&amp;</span> <span class="identifier">arg</span><span class="special">);</span>
<span class="keyword">void</span> <span class="identifier">emplace</span><span class="special">();</span>
</pre>
<p>
On compilers that do not support rvalue references, each of these functions
is substituted with three overloadss: taking <code class="computeroutput"><span class="keyword">const</span></code>
and non-<code class="computeroutput"><span class="keyword">const</span></code> lvalue reference,
and third forwarding zero arguments. This forms the following set:
</p>
<pre class="programlisting"><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">Arg</span><span class="special">&gt;</span> <span class="identifier">optional</span><span class="special">(</span><span class="identifier">in_place_init_t</span><span class="special">,</span> <span class="keyword">const</span> <span class="identifier">Arg</span><span class="special">&amp;</span> <span class="identifier">arg</span><span class="special">);</span>
<span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">Arg</span><span class="special">&gt;</span> <span class="identifier">optional</span><span class="special">(</span><span class="identifier">in_place_init_t</span><span class="special">,</span> <span class="identifier">Arg</span><span class="special">&amp;</span> <span class="identifier">arg</span><span class="special">);</span>
<span class="identifier">optional</span><span class="special">(</span><span class="identifier">in_place_init_t</span><span class="special">);</span>
<span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">Arg</span><span class="special">&gt;</span> <span class="identifier">optional</span><span class="special">(</span><span class="identifier">in_place_init_if_t</span><span class="special">,</span> <span class="keyword">bool</span> <span class="identifier">condition</span><span class="special">,</span> <span class="keyword">const</span> <span class="identifier">Arg</span><span class="special">&amp;</span> <span class="identifier">arg</span><span class="special">);</span>
<span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">Arg</span><span class="special">&gt;</span> <span class="identifier">optional</span><span class="special">(</span><span class="identifier">in_place_init_if_t</span><span class="special">,</span> <span class="keyword">bool</span> <span class="identifier">condition</span><span class="special">,</span> <span class="identifier">Arg</span><span class="special">&amp;</span> <span class="identifier">arg</span><span class="special">);</span>
<span class="identifier">optional</span><span class="special">(</span><span class="identifier">in_place_init_if_t</span><span class="special">,</span> <span class="keyword">bool</span> <span class="identifier">condition</span><span class="special">);</span>
<span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">Arg</span><span class="special">&gt;</span> <span class="keyword">void</span> <span class="identifier">emplace</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">Arg</span><span class="special">&amp;</span> <span class="identifier">arg</span><span class="special">);</span>
<span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">Arg</span><span class="special">&gt;</span> <span class="keyword">void</span> <span class="identifier">emplace</span><span class="special">(</span><span class="identifier">Arg</span><span class="special">&amp;</span> <span class="identifier">arg</span><span class="special">);</span>
<span class="keyword">void</span> <span class="identifier">emplace</span><span class="special">();</span>
</pre>
<p>
This workaround addressess about 40% of all use cases. If this is insufficient,
you need to resort to using <a class="link" href="../tutorial/in_place_factories.html" title="In-Place Factories">In-Place
Factories</a>.
</p>
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<td align="right"><div class="copyright-footer">Copyright &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2016 Andrzej Krzemie&#324;ski<p>
Distributed under the Boost Software License, Version 1.0. (See accompanying
file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
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</pre>
</li>
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<p>
<span class="inlinemediaobject"><img src="../../../images/space.png" alt="space"></span>
</p>
<a name="reference_optional_in_place_init"></a><div class="blockquote"><blockquote class="blockquote"><p>
<code class="computeroutput"><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span><span class="special">...</span> <span class="identifier">Args</span><span class="special">&gt;</span>
<span class="keyword">explicit</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;::</span><span class="identifier">optional</span><span class="special">(</span> <span class="identifier">in_place_init_t</span><span class="special">,</span> <span class="identifier">Args</span><span class="special">&amp;&amp;...</span> <span class="identifier">ars</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="identifier">is_constructible_v</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">,</span> <span class="identifier">Args</span><span class="special">&amp;&amp;...&gt;</span></code> is <code class="computeroutput"><span class="keyword">true</span></code>.
</li>
<li class="listitem">
<span class="bold"><strong>Effect:</strong></span> Initializes the contained
value as if direct-non-list-initializing an object of type <code class="computeroutput"><span class="identifier">T</span></code> with the arguments <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">forward</span><span class="special">&lt;</span><span class="identifier">Args</span><span class="special">&gt;(</span><span class="identifier">args</span><span class="special">)...</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.
</li>
<li class="listitem">
<span class="bold"><strong>Throws:</strong></span> Any exception thrown by the
selected constructor of <code class="computeroutput"><span class="identifier">T</span></code>.
</li>
<li class="listitem">
<span class="bold"><strong>Notes: </strong></span> <code class="computeroutput"><span class="identifier">T</span></code>
need not be <code class="computeroutput"><span class="identifier">MoveConstructible</span></code>.
On compilers that do not suppor variadic templates or rvalue references,
this constuctor is available in limited functionality. For details
<a class="link" href="../../dependencies_and_portability/emplace_operations_in_older_compilers.html#optional_emplace_workaround">see here</a>.
</li>
<li class="listitem">
<span class="bold"><strong>Example:</strong></span>
<pre class="programlisting"><span class="comment">// creates an std::mutex using its default constructor</span>
<span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">mutex</span><span class="special">&gt;</span> <span class="identifier">om</span> <span class="special">{</span><span class="identifier">in_place_init</span><span class="special">};</span>
<span class="identifier">assert</span> <span class="special">(</span><span class="identifier">om</span><span class="special">);</span>
<span class="comment">// creates a unique_lock by calling unique_lock(*om, std::defer_lock)</span>
<span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">unique_lock</span><span class="special">&lt;</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">mutex</span><span class="special">&gt;&gt;</span> <span class="identifier">ol</span> <span class="special">{</span><span class="identifier">in_place_init</span><span class="special">,</span> <span class="special">*</span><span class="identifier">om</span><span class="special">,</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">defer_lock</span><span class="special">};</span>
<span class="identifier">assert</span> <span class="special">(</span><span class="identifier">ol</span><span class="special">);</span>
<span class="identifier">assert</span> <span class="special">(!</span><span class="identifier">ol</span><span class="special">-&gt;</span><span class="identifier">owns_lock</span><span class="special">());</span>
</pre>
</li>
</ul></div>
<p>
<span class="inlinemediaobject"><img src="../../../images/space.png" alt="space"></span>
</p>
<a name="reference_optional_in_place_init_if"></a><div class="blockquote"><blockquote class="blockquote"><p>
<code class="computeroutput"><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span><span class="special">...</span> <span class="identifier">Args</span><span class="special">&gt;</span>
<span class="keyword">explicit</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;::</span><span class="identifier">optional</span><span class="special">(</span> <span class="identifier">in_place_init_if_t</span><span class="special">,</span> <span class="keyword">bool</span> <span class="identifier">condition</span><span class="special">,</span>
<span class="identifier">Args</span><span class="special">&amp;&amp;...</span>
<span class="identifier">ars</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="identifier">is_constructible_v</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">,</span> <span class="identifier">Args</span><span class="special">&amp;&amp;...&gt;</span></code> is <code class="computeroutput"><span class="keyword">true</span></code>.
</li>
<li class="listitem">
<span class="bold"><strong>Effect:</strong></span> If <code class="computeroutput"><span class="identifier">condition</span></code>
is <code class="computeroutput"><span class="keyword">true</span></code>, initializes the
contained value as if direct-non-list-initializing an object of type
<code class="computeroutput"><span class="identifier">T</span></code> with the arguments
<code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">forward</span><span class="special">&lt;</span><span class="identifier">Args</span><span class="special">&gt;(</span><span class="identifier">args</span><span class="special">)...</span></code>.
</li>
<li class="listitem">
<span class="bold"><strong>Postconditions:</strong></span> <code class="computeroutput"><span class="keyword">bool</span><span class="special">(*</span><span class="keyword">this</span><span class="special">)</span> <span class="special">==</span> <span class="identifier">condition</span></code>.
</li>
<li class="listitem">
<span class="bold"><strong>Throws:</strong></span> Any exception thrown by the
selected constructor of <code class="computeroutput"><span class="identifier">T</span></code>.
</li>
<li class="listitem">
<span class="bold"><strong>Notes: </strong></span> <code class="computeroutput"><span class="identifier">T</span></code>
need not be <code class="computeroutput"><span class="identifier">MoveConstructible</span></code>.
On compilers that do not suppor variadic templates or rvalue references,
this constuctor is available in limited functionality. For details
<a class="link" href="../../dependencies_and_portability/emplace_operations_in_older_compilers.html#optional_emplace_workaround">see here</a>.
</li>
<li class="listitem">
<span class="bold"><strong>Example:</strong></span>
<pre class="programlisting"><span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">vector</span><span class="special">&lt;</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span><span class="special">&gt;&gt;</span> <span class="identifier">ov1</span> <span class="special">{</span><span class="identifier">in_place_init_if</span><span class="special">,</span> <span class="keyword">false</span><span class="special">,</span> <span class="number">3</span><span class="special">,</span> <span class="string">"A"</span><span class="special">};</span>
<span class="identifier">assert</span> <span class="special">(!</span><span class="identifier">ov1</span><span class="special">);</span>
<span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">vector</span><span class="special">&lt;</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span><span class="special">&gt;&gt;</span> <span class="identifier">ov2</span> <span class="special">{</span><span class="identifier">in_place_init_if</span><span class="special">,</span> <span class="keyword">true</span><span class="special">,</span> <span class="number">3</span><span class="special">,</span> <span class="string">"A"</span><span class="special">};</span>
<span class="identifier">assert</span> <span class="special">(</span><span class="identifier">ov2</span><span class="special">);</span>
<span class="identifier">assert</span> <span class="special">(</span><span class="identifier">ov2</span><span class="special">-&gt;</span><span class="identifier">size</span><span class="special">()</span> <span class="special">==</span> <span class="number">3</span><span class="special">);</span>
</pre>
</li>
</ul></div>
<p>
<span class="inlinemediaobject"><img src="../../../images/space.png" alt="space"></span>
</p>
@ -1037,15 +1125,8 @@
<span class="bold"><strong>Notes:</strong></span> <code class="computeroutput"><span class="identifier">T</span></code>
need not be <code class="computeroutput"><span class="identifier">MoveConstructible</span></code>
or <code class="computeroutput"><span class="identifier">MoveAssignable</span></code>.
On compilers that do not support variadic templates, the signature
falls back to two overloads:<code class="computeroutput"><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span>
<span class="identifier">Arg</span><span class="special">&gt;</span>
<span class="keyword">void</span> <span class="identifier">emplace</span><span class="special">(</span><span class="identifier">Arg</span><span class="special">&amp;&amp;</span> <span class="identifier">arg</span><span class="special">)</span></code> and <code class="computeroutput"><span class="keyword">void</span>
<span class="identifier">emplace</span><span class="special">()</span></code>.
On compilers that do not support rvalue references, the signature falls
back to three overloads: taking <code class="computeroutput"><span class="keyword">const</span></code>
and non-<code class="computeroutput"><span class="keyword">const</span></code> lvalue reference,
and third with empty function argument list.
On compilers that do not suppor variadic templates or rvalue references,
this function is available in limited functionality. For details <a class="link" href="../../dependencies_and_portability/emplace_operations_in_older_compilers.html#optional_emplace_workaround">see here</a>.
</li>
<li class="listitem">
<span class="bold"><strong>Example:</strong></span>

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@ -0,0 +1,61 @@
<html>
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<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
<title>Initialization tags</title>
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<a name="boost_optional.reference.header__boost_optional_optional_hpp_.header_optional_in_place_init"></a><a class="link" href="header_optional_in_place_init.html" title="Initialization tags">Initialization
tags</a>
</h4></div></div></div>
<a name="reference_in_place_init"></a><a name="reference_in_place_init_if"></a><pre class="programlisting"><span class="keyword">namespace</span> <span class="identifier">boost</span> <span class="special">{</span>
<span class="keyword">class</span> <span class="identifier">in_place_init_t</span> <span class="special">{</span> <span class="comment">/* see below */</span> <span class="special">}</span> <span class="special">;</span>
<span class="keyword">const</span> <span class="identifier">in_place_init_t</span> <span class="identifier">in_place_init</span> <span class="special">(</span> <span class="comment">/* see below */</span> <span class="special">)</span> <span class="special">;</span>
<span class="keyword">class</span> <span class="identifier">in_place_init_if_t</span> <span class="special">{</span> <span class="comment">/*see below*/</span> <span class="special">}</span> <span class="special">;</span>
<span class="keyword">const</span> <span class="identifier">in_place_init_if_t</span> <span class="identifier">in_place_init_if</span> <span class="special">(</span> <span class="comment">/*see below*/</span> <span class="special">)</span> <span class="special">;</span>
<span class="special">}</span>
</pre>
<p>
Classes <code class="computeroutput"><span class="identifier">in_place_init_t</span></code>
and <code class="computeroutput"><span class="identifier">in_place_init_if_t</span></code>
are empty clsses. Their purpose is to control overload resolution in the
initialization of optional objects. They are empty, trivially copyable
classes with disabled default constructor.
</p>
</div>
<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
<td align="left"></td>
<td align="right"><div class="copyright-footer">Copyright &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2016 Andrzej Krzemie&#324;ski<p>
Distributed under the Boost Software License, Version 1.0. (See accompanying
file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
</p>
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@ -6,7 +6,7 @@
<meta name="generator" content="DocBook XSL Stylesheets V1.78.1">
<link rel="home" href="../../../index.html" title="Boost.Optional">
<link rel="up" href="../../../optional/reference/header__boost_optional_optional_hpp_.html" title="Header &lt;boost/optional/optional.hpp&gt;">
<link rel="prev" href="../../../optional/reference/header__boost_optional_optional_hpp_.html" title="Header &lt;boost/optional/optional.hpp&gt;">
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<link rel="next" href="header_optional_optional_refs.html" title="Optional References">
</head>
<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
@ -20,7 +20,7 @@
</tr></table>
<hr>
<div class="spirit-nav">
<a accesskey="p" href="../../../optional/reference/header__boost_optional_optional_hpp_.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../../../optional/reference/header__boost_optional_optional_hpp_.html"><img src="../../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../../index.html"><img src="../../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="header_optional_optional_refs.html"><img src="../../../../../../../doc/src/images/next.png" alt="Next"></a>
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</div>
<div class="section">
<div class="titlepage"><div><div><h4 class="title">
@ -47,7 +47,6 @@
<span class="identifier">optional</span> <span class="special">(</span> <span class="identifier">T</span><span class="special">&amp;&amp;</span> <span class="identifier">v</span> <span class="special">)</span> <span class="special">;</span> <a class="link" href="detailed_semantics___optional_values.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">&amp;</span> <span class="identifier">v</span> <span class="special">)</span> <span class="special">;</span> <a class="link" href="detailed_semantics___optional_values.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">&amp;</span> <span class="identifier">rhs</span> <span class="special">)</span> <span class="special">;</span> <a class="link" href="detailed_semantics___optional_values.html#reference_optional_constructor_optional"><span class="inlinemediaobject"><img src="../../../images/callouts/R.png" alt="R"></span></a>
@ -58,6 +57,10 @@
<span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">U</span><span class="special">&gt;</span> <span class="keyword">explicit</span> <span class="identifier">optional</span> <span class="special">(</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">U</span><span class="special">&gt;&amp;&amp;</span> <span class="identifier">rhs</span> <span class="special">)</span> <span class="special">;</span> <a class="link" href="detailed_semantics___optional_values.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">&lt;</span><span class="keyword">class</span><span class="special">...</span> <span class="identifier">Args</span><span class="special">&gt;</span> <span class="keyword">explicit</span> <span class="identifier">optional</span> <span class="special">(</span> <span class="identifier">in_place_init_t</span><span class="special">,</span> <span class="identifier">Args</span><span class="special">&amp;&amp;...</span> <span class="identifier">args</span> <span class="special">)</span> <span class="special">;</span> <a class="link" href="detailed_semantics___optional_values.html#reference_optional_in_place_init"><span class="inlinemediaobject"><img src="../../../images/callouts/R.png" alt="R"></span></a>
<span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span><span class="special">...</span> <span class="identifier">Args</span><span class="special">&gt;</span> <span class="keyword">explicit</span> <span class="identifier">optional</span> <span class="special">(</span> <span class="identifier">in_place_init_if_t</span><span class="special">,</span> <span class="keyword">bool</span> <span class="identifier">condition</span><span class="special">,</span> <span class="identifier">Args</span><span class="special">&amp;&amp;...</span> <span class="identifier">args</span> <span class="special">)</span> <span class="special">;</span> <a class="link" href="detailed_semantics___optional_values.html#reference_optional_in_place_init_if"><span class="inlinemediaobject"><img src="../../../images/callouts/R.png" alt="R"></span></a>
<span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">InPlaceFactory</span><span class="special">&gt;</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">&amp;</span> <span class="identifier">f</span> <span class="special">)</span> <span class="special">;</span> <a class="link" href="detailed_semantics___optional_values.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">&lt;</span><span class="keyword">class</span> <span class="identifier">TypedInPlaceFactory</span><span class="special">&gt;</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">&amp;</span> <span class="identifier">f</span> <span class="special">)</span> <span class="special">;</span> <a class="link" href="detailed_semantics___optional_values.html#reference_optional_constructor_factory"><span class="inlinemediaobject"><img src="../../../images/callouts/R.png" alt="R"></span></a>
@ -135,7 +138,7 @@
</tr></table>
<hr>
<div class="spirit-nav">
<a accesskey="p" href="../../../optional/reference/header__boost_optional_optional_hpp_.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../../../optional/reference/header__boost_optional_optional_hpp_.html"><img src="../../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../../index.html"><img src="../../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="header_optional_optional_refs.html"><img src="../../../../../../../doc/src/images/next.png" alt="Next"></a>
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28
doc/html/boost_optional/relnotes.html
View File

@ -28,6 +28,22 @@
</h2></div></div></div>
<h4>
<a name="boost_optional.relnotes.h0"></a>
<span class="phrase"><a name="boost_optional.relnotes.boost_release_1_63"></a></span><a class="link" href="relnotes.html#boost_optional.relnotes.boost_release_1_63">Boost
Release 1.63</a>
</h4>
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
Added two new in-place constructors. They work similarly to <code class="computeroutput"><span class="identifier">emplace</span><span class="special">()</span></code>
functions: they initialize the contained value by perfect-forwarding the
obtained arguments. One constructor always initializes the contained value,
the other based on a boolean condition.
</li>
<li class="listitem">
Fixed <a href="https://svn.boost.org/trac/boost/ticket/12203" target="_top">Trac #12203</a>.
</li>
</ul></div>
<h4>
<a name="boost_optional.relnotes.h1"></a>
<span class="phrase"><a name="boost_optional.relnotes.boost_release_1_62"></a></span><a class="link" href="relnotes.html#boost_optional.relnotes.boost_release_1_62">Boost
Release 1.62</a>
</h4>
@ -35,7 +51,7 @@
Fixed <a href="https://svn.boost.org/trac/boost/ticket/12179" target="_top">Trac #12179</a>.
</li></ul></div>
<h4>
<a name="boost_optional.relnotes.h1"></a>
<a name="boost_optional.relnotes.h2"></a>
<span class="phrase"><a name="boost_optional.relnotes.boost_release_1_61"></a></span><a class="link" href="relnotes.html#boost_optional.relnotes.boost_release_1_61">Boost
Release 1.61</a>
</h4>
@ -78,7 +94,7 @@
</li>
</ul></div>
<h4>
<a name="boost_optional.relnotes.h2"></a>
<a name="boost_optional.relnotes.h3"></a>
<span class="phrase"><a name="boost_optional.relnotes.boost_release_1_60"></a></span><a class="link" href="relnotes.html#boost_optional.relnotes.boost_release_1_60">Boost
Release 1.60</a>
</h4>
@ -89,7 +105,7 @@
#11203</a>.
</li></ul></div>
<h4>
<a name="boost_optional.relnotes.h3"></a>
<a name="boost_optional.relnotes.h4"></a>
<span class="phrase"><a name="boost_optional.relnotes.boost_release_1_59"></a></span><a class="link" href="relnotes.html#boost_optional.relnotes.boost_release_1_59">Boost
Release 1.59</a>
</h4>
@ -103,7 +119,7 @@
</li>
</ul></div>
<h4>
<a name="boost_optional.relnotes.h4"></a>
<a name="boost_optional.relnotes.h5"></a>
<span class="phrase"><a name="boost_optional.relnotes.boost_release_1_58"></a></span><a class="link" href="relnotes.html#boost_optional.relnotes.boost_release_1_58">Boost
Release 1.58</a>
</h4>
@ -139,7 +155,7 @@
</li>
</ul></div>
<h4>
<a name="boost_optional.relnotes.h5"></a>
<a name="boost_optional.relnotes.h6"></a>
<span class="phrase"><a name="boost_optional.relnotes.boost_release_1_57"></a></span><a class="link" href="relnotes.html#boost_optional.relnotes.boost_release_1_57">Boost
Release 1.57</a>
</h4>
@ -149,7 +165,7 @@
to fix C++03 compile error on <code class="computeroutput"><span class="identifier">logic_error</span><span class="special">(</span><span class="string">"..."</span><span class="special">)</span></code>"</em></span>.
</li></ul></div>
<h4>
<a name="boost_optional.relnotes.h6"></a>
<a name="boost_optional.relnotes.h7"></a>
<span class="phrase"><a name="boost_optional.relnotes.boost_release_1_56"></a></span><a class="link" href="relnotes.html#boost_optional.relnotes.boost_release_1_56">Boost
Release 1.56</a>
</h4>