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@ -35,12 +35,12 @@
optional<string> name ;
if ( database.open() )
{
name.reset ( database.lookup(employer_name) ) ;
name = database.lookup(employer_name) ;
}
else
{
if ( can_ask_user )
name.reset ( user.ask(employer_name) ) ;
name = user.ask(employer_name) ;
}
if ( name )
@ -63,7 +63,7 @@
void clip_in_rect ( rect const& rect )
{
....
m_clipping_rect.reset ( rect ) ; // initialized here.
m_clipping_rect = rect ; // initialized here.
}
void draw ( canvas& cvs )

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@ -3,7 +3,7 @@
<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
<title>A note about optional&lt;bool&gt;</title>
<link rel="stylesheet" href="../boostbook.css" type="text/css">
<meta name="generator" content="DocBook XSL Stylesheets V1.75.2">
<meta name="generator" content="DocBook XSL Stylesheets V1.77.1">
<link rel="home" href="../index.html" title="Chapter&#160;1.&#160;Boost.Optional">
<link rel="up" href="../index.html" title="Chapter&#160;1.&#160;Boost.Optional">
<link rel="prev" href="in_place_factories.html" title="In-Place Factories">
@ -22,7 +22,7 @@
<div class="spirit-nav">
<a accesskey="p" href="in_place_factories.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.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="exception_safety_guarantees.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a>
</div>
<div class="section">
<div class="section boost_optional_a_note_about_optional_bool_">
<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="boost_optional.a_note_about_optional_bool_"></a><a class="link" href="a_note_about_optional_bool_.html" title="A note about optional&lt;bool&gt;">A note about
optional&lt;bool&gt;</a>
@ -54,11 +54,11 @@
<span class="special">{</span>
<span class="identifier">optional</span><span class="special">&lt;</span><span class="keyword">bool</span><span class="special">&gt;</span> <span class="identifier">v</span> <span class="special">=</span> <span class="keyword">try</span><span class="special">();</span>
<span class="comment">// The following intended to pass the value of 'v' to foo():
</span> <span class="identifier">foo</span><span class="special">(</span><span class="identifier">v</span><span class="special">);</span>
<span class="comment">// But instead, the initialization state is passed
</span> <span class="comment">// due to a typo: it should have been foo(*v).
</span><span class="special">}</span>
<span class="comment">// The following intended to pass the value of 'v' to foo():</span>
<span class="identifier">foo</span><span class="special">(</span><span class="identifier">v</span><span class="special">);</span>
<span class="comment">// But instead, the initialization state is passed</span>
<span class="comment">// due to a typo: it should have been foo(*v).</span>
<span class="special">}</span>
</pre>
<p>
The only implicit conversion is to <code class="computeroutput"><span class="keyword">bool</span></code>,

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@ -3,7 +3,7 @@
<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
<title>Acknowledgments</title>
<link rel="stylesheet" href="../boostbook.css" type="text/css">
<meta name="generator" content="DocBook XSL Stylesheets V1.75.2">
<meta name="generator" content="DocBook XSL Stylesheets V1.77.1">
<link rel="home" href="../index.html" title="Chapter&#160;1.&#160;Boost.Optional">
<link rel="up" href="../index.html" title="Chapter&#160;1.&#160;Boost.Optional">
<link rel="prev" href="dependencies_and_portability.html" title="Dependencies and Portability">
@ -21,16 +21,16 @@
<div class="spirit-nav">
<a accesskey="p" href="dependencies_and_portability.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.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>
</div>
<div class="section">
<div class="section boost_optional_acknowledgments">
<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="boost_optional.acknowledgments"></a><a class="link" href="acknowledgments.html" title="Acknowledgments">Acknowledgments</a>
</h2></div></div></div>
<a name="boost_optional.acknowledgments.pre_formal_review"></a><h4>
<a name="boost_optional.acknowledgments.pre_formal_review-heading"></a>
<a class="link" href="acknowledgments.html#boost_optional.acknowledgments.pre_formal_review">Pre-formal
<h4>
<a name="boost_optional.acknowledgments.h0"></a>
<span class="phrase"><a name="boost_optional.acknowledgments.pre_formal_review"></a></span><a class="link" href="acknowledgments.html#boost_optional.acknowledgments.pre_formal_review">Pre-formal
review</a>
</h4>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
Peter Dimov suggested the name 'optional', and was the first to point out
the need for aligned storage.
@ -64,12 +64,12 @@
Henney, David Abrahams, and others I can't recall.
</li>
</ul></div>
<a name="boost_optional.acknowledgments.post_formal_review"></a><h4>
<a name="boost_optional.acknowledgments.post_formal_review-heading"></a>
<a class="link" href="acknowledgments.html#boost_optional.acknowledgments.post_formal_review">Post-formal
<h4>
<a name="boost_optional.acknowledgments.h1"></a>
<span class="phrase"><a name="boost_optional.acknowledgments.post_formal_review"></a></span><a class="link" href="acknowledgments.html#boost_optional.acknowledgments.post_formal_review">Post-formal
review</a>
</h4>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
William Kempf carefully considered the originally proposed interface and
suggested the new interface which is currently used. He also started and

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@ -3,7 +3,7 @@
<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
<title>Dependencies and Portability</title>
<link rel="stylesheet" href="../boostbook.css" type="text/css">
<meta name="generator" content="DocBook XSL Stylesheets V1.75.2">
<meta name="generator" content="DocBook XSL Stylesheets V1.77.1">
<link rel="home" href="../index.html" title="Chapter&#160;1.&#160;Boost.Optional">
<link rel="up" href="../index.html" title="Chapter&#160;1.&#160;Boost.Optional">
<link rel="prev" href="implementation_notes.html" title="Implementation Notes">
@ -22,7 +22,7 @@
<div class="spirit-nav">
<a accesskey="p" href="implementation_notes.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.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="acknowledgments.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a>
</div>
<div class="section">
<div class="section boost_optional_dependencies_and_portability">
<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="boost_optional.dependencies_and_portability"></a><a class="link" href="dependencies_and_portability.html" title="Dependencies and Portability">Dependencies
and Portability</a>

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@ -3,7 +3,7 @@
<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
<title>Detailed Semantics</title>
<link rel="stylesheet" href="../boostbook.css" type="text/css">
<meta name="generator" content="DocBook XSL Stylesheets V1.75.2">
<meta name="generator" content="DocBook XSL Stylesheets V1.77.1">
<link rel="home" href="../index.html" title="Chapter&#160;1.&#160;Boost.Optional">
<link rel="up" href="../index.html" title="Chapter&#160;1.&#160;Boost.Optional">
<link rel="prev" href="synopsis.html" title="Synopsis">
@ -22,7 +22,7 @@
<div class="spirit-nav">
<a accesskey="p" href="synopsis.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.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="examples.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a>
</div>
<div class="section">
<div class="section boost_optional_detailed_semantics">
<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="boost_optional.detailed_semantics"></a><a class="link" href="detailed_semantics.html" title="Detailed Semantics">Detailed Semantics</a>
</h2></div></div></div>
@ -31,7 +31,7 @@
type, in the sequel, those entries whose semantic depends on <code class="computeroutput"><span class="identifier">T</span></code> being of reference type or not will be
distinguished using the following convention:
</p>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
If the entry reads: <code class="computeroutput"><span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span></code><span class="emphasis"><em>(not
a ref)</em></span><code class="computeroutput"><span class="special">&gt;</span></code>, the
@ -63,9 +63,9 @@
<p>
<span class="inlinemediaobject"><img src="../images/space.png" alt="space"></span>
</p>
<a name="boost_optional.detailed_semantics.optional_class_member_functions"></a><h4>
<a name="boost_optional.detailed_semantics.optional_class_member_functions-heading"></a>
<a class="link" href="detailed_semantics.html#boost_optional.detailed_semantics.optional_class_member_functions">optional
<h4>
<a name="boost_optional.detailed_semantics.h0"></a>
<span class="phrase"><a name="boost_optional.detailed_semantics.optional_class_member_functions"></a></span><a class="link" href="detailed_semantics.html#boost_optional.detailed_semantics.optional_class_member_functions">optional
class member functions</a>
</h4>
<p>
@ -74,7 +74,7 @@
<a name="reference_optional_constructor"></a><div class="blockquote"><blockquote class="blockquote"><p>
<code class="computeroutput"><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></code>
</p></blockquote></div>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<span class="bold"><strong>Effect:</strong></span> Default-Constructs an <code class="computeroutput"><span class="identifier">optional</span></code>.
</li>
@ -89,7 +89,7 @@
called.
</li>
<li class="listitem">
<span class="bold"><strong>Example:</strong></span>
<span class="bold"><strong>Example:</strong></span>
<pre class="programlisting"><span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span> <span class="identifier">def</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="special">;</span>
</pre>
@ -101,7 +101,7 @@
<a name="reference_optional_constructor_none_t"></a><div class="blockquote"><blockquote class="blockquote"><p>
<code class="computeroutput"><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">none_t</span> <span class="special">);</span></code>
</p></blockquote></div>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<span class="bold"><strong>Effect:</strong></span> Constructs an <code class="computeroutput"><span class="identifier">optional</span></code>
uninitialized.
@ -118,7 +118,7 @@
The expression <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">none</span></code> denotes an instance of <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">none_t</span></code> that can be used as the parameter.
</li>
<li class="listitem">
<span class="bold"><strong>Example:</strong></span>
<span class="bold"><strong>Example:</strong></span>
<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">none</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>
<span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span> <span class="identifier">n</span><span class="special">(</span><span class="identifier">none</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">n</span> <span class="special">)</span> <span class="special">;</span>
@ -131,7 +131,7 @@
<a name="reference_optional_constructor_value"></a><div class="blockquote"><blockquote class="blockquote"><p>
<code class="computeroutput"><span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span> </code><span class="emphasis"><em>(not a ref)</em></span><code class="computeroutput"><span class="special">&gt;::</span><span class="identifier">optional</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></code>
</p></blockquote></div>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<span class="bold"><strong>Effect:</strong></span> Directly-Constructs an <code class="computeroutput"><span class="identifier">optional</span></code>.
</li>
@ -157,7 +157,7 @@
has no effect.
</li>
<li class="listitem">
<span class="bold"><strong>Example:</strong></span>
<span class="bold"><strong>Example:</strong></span>
<pre class="programlisting"><span class="identifier">T</span> <span class="identifier">v</span><span class="special">;</span>
<span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span> <span class="identifier">opt</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">opt</span> <span class="special">==</span> <span class="identifier">v</span> <span class="special">)</span> <span class="special">;</span>
@ -170,7 +170,7 @@
<div class="blockquote"><blockquote class="blockquote"><p>
<code class="computeroutput"><span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&amp;&gt;::</span><span class="identifier">optional</span><span class="special">(</span> <span class="identifier">T</span><span class="special">&amp;</span> <span class="identifier">ref</span> <span class="special">)</span></code>
</p></blockquote></div>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<span class="bold"><strong>Effect:</strong></span> Directly-Constructs an <code class="computeroutput"><span class="identifier">optional</span></code>.
</li>
@ -183,13 +183,13 @@
<span class="bold"><strong>Throws:</strong></span> Nothing.
</li>
<li class="listitem">
<span class="bold"><strong>Example:</strong></span>
<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">T</span><span class="special">&amp;</span> <span class="identifier">vref</span> <span class="special">=</span> <span class="identifier">v</span> <span class="special">;</span>
<span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&amp;&gt;</span> <span class="identifier">opt</span><span class="special">(</span><span class="identifier">vref</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">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="comment">// mutate referee
</span><span class="identifier">assert</span> <span class="special">(*</span><span class="identifier">opt</span> <span class="special">==</span> <span class="identifier">v</span><span class="special">);</span>
<span class="special">++</span> <span class="identifier">v</span> <span class="special">;</span> <span class="comment">// mutate referee</span>
<span class="identifier">assert</span> <span class="special">(*</span><span class="identifier">opt</span> <span class="special">==</span> <span class="identifier">v</span><span class="special">);</span>
</pre>
</li>
</ul></div>
@ -203,7 +203,7 @@
<code class="computeroutput"><span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&amp;&gt;</span> <span class="special">::</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="special">&amp;</span>
<span class="identifier">v</span> <span class="special">)</span> <span class="special">;</span></code>
</p></blockquote></div>
<div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem">
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem">
If condition is true, same as:
</li></ul></div>
<div class="blockquote"><blockquote class="blockquote"><p>
@ -213,7 +213,7 @@
<code class="computeroutput"><span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&amp;&gt;</span> <span class="special">::</span><span class="identifier">optional</span><span class="special">(</span> <span class="identifier">T</span><span class="special">&amp;</span>
<span class="identifier">v</span> <span class="special">)</span></code>
</p></blockquote></div>
<div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem">
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem">
otherwise, same as:
</li></ul></div>
<div class="blockquote"><blockquote class="blockquote"><p>
@ -228,7 +228,7 @@
<a name="reference_optional_constructor_optional"></a><div class="blockquote"><blockquote class="blockquote"><p>
<code class="computeroutput"><span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span> </code><span class="emphasis"><em>(not a ref)</em></span><code class="computeroutput"><span class="special">&gt;::</span><span class="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></code>
</p></blockquote></div>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<span class="bold"><strong>Effect:</strong></span> Copy-Constructs an <code class="computeroutput"><span class="identifier">optional</span></code>.
</li>
@ -256,7 +256,7 @@
has no effect.
</li>
<li class="listitem">
<span class="bold"><strong>Example:</strong></span>
<span class="bold"><strong>Example:</strong></span>
<pre class="programlisting"><span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</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>
@ -277,7 +277,7 @@
<div class="blockquote"><blockquote class="blockquote"><p>
<code class="computeroutput"><span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&amp;&gt;::</span><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></code>
</p></blockquote></div>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<span class="bold"><strong>Effect:</strong></span> Copy-Constructs an <code class="computeroutput"><span class="identifier">optional</span></code>.
</li>
@ -299,7 +299,7 @@
will reefer to the same object (they alias).
</li>
<li class="listitem">
<span class="bold"><strong>Example:</strong></span>
<span class="bold"><strong>Example:</strong></span>
<pre class="programlisting"><span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&amp;&gt;</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>
@ -327,7 +327,7 @@
<code class="computeroutput"><span class="keyword">template</span><span class="special">&lt;</span><span class="identifier">U</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></code>
<span class="emphasis"><em>(not a ref)</em></span><code class="computeroutput"><span class="special">&gt;::</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;</span> <span class="keyword">const</span><span class="special">&amp;</span> <span class="identifier">rhs</span> <span class="special">);</span></code>
</p></blockquote></div>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<span class="bold"><strong>Effect:</strong></span> Copy-Constructs an <code class="computeroutput"><span class="identifier">optional</span></code>.
</li>
@ -359,7 +359,7 @@
has no effect.
</li>
<li class="listitem">
<span class="bold"><strong>Example:</strong></span>
<span class="bold"><strong>Example:</strong></span>
<pre class="programlisting"><span class="identifier">optional</span><span class="special">&lt;</span><span class="keyword">double</span><span class="special">&gt;</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>
@ -381,7 +381,7 @@
<span class="keyword">explicit</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span></code>
<span class="emphasis"><em>(not a ref)</em></span><code class="computeroutput"><span class="special">&gt;::</span><span class="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></code>
</p></blockquote></div>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<span class="bold"><strong>Effect:</strong></span> Constructs an <code class="computeroutput"><span class="identifier">optional</span></code>
with a value of <code class="computeroutput"><span class="identifier">T</span></code> obtained
@ -407,14 +407,14 @@
effect.
</li>
<li class="listitem">
<span class="bold"><strong>Example:</strong></span>
<span class="bold"><strong>Example:</strong></span>
<pre class="programlisting"><span class="keyword">class</span> <span class="identifier">C</span> <span class="special">{</span> <span class="identifier">C</span> <span class="special">(</span> <span class="keyword">char</span><span class="special">,</span> <span class="keyword">double</span><span class="special">,</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span> <span class="special">)</span> <span class="special">;</span> <span class="special">}</span> <span class="special">;</span>
<span class="identifier">C</span> <span class="identifier">v</span><span class="special">(</span><span class="char">'A'</span><span class="special">,</span><span class="number">123.4</span><span class="special">,</span><span class="string">"hello"</span><span class="special">);</span>
<span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">C</span><span class="special">&gt;</span> <span class="identifier">x</span><span class="special">(</span> <span class="identifier">in_place</span> <span class="special">(</span><span class="char">'A'</span><span class="special">,</span> <span class="number">123.4</span><span class="special">,</span> <span class="string">"hello"</span><span class="special">)</span> <span class="special">);</span> <span class="comment">// InPlaceFactory used
</span><span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">C</span><span class="special">&gt;</span> <span class="identifier">y</span><span class="special">(</span> <span class="identifier">in_place</span><span class="special">&lt;</span><span class="identifier">C</span><span class="special">&gt;(</span><span class="char">'A'</span><span class="special">,</span> <span class="number">123.4</span><span class="special">,</span> <span class="string">"hello"</span><span class="special">)</span> <span class="special">);</span> <span class="comment">// TypedInPlaceFactory used
</span>
<span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">C</span><span class="special">&gt;</span> <span class="identifier">x</span><span class="special">(</span> <span class="identifier">in_place</span> <span class="special">(</span><span class="char">'A'</span><span class="special">,</span> <span class="number">123.4</span><span class="special">,</span> <span class="string">"hello"</span><span class="special">)</span> <span class="special">);</span> <span class="comment">// InPlaceFactory used</span>
<span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">C</span><span class="special">&gt;</span> <span class="identifier">y</span><span class="special">(</span> <span class="identifier">in_place</span><span class="special">&lt;</span><span class="identifier">C</span><span class="special">&gt;(</span><span class="char">'A'</span><span class="special">,</span> <span class="number">123.4</span><span class="special">,</span> <span class="string">"hello"</span><span class="special">)</span> <span class="special">);</span> <span class="comment">// TypedInPlaceFactory used</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="identifier">v</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="identifier">v</span> <span class="special">)</span> <span class="special">;</span>
</pre>
@ -430,7 +430,7 @@
<span class="identifier">rhs</span> <span class="special">)</span>
<span class="special">;</span></code>
</p></blockquote></div>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<span class="bold"><strong>Effect:</strong></span> Assigns the value <code class="computeroutput"><span class="identifier">rhs</span></code> to an <code class="computeroutput"><span class="identifier">optional</span></code>.
</li>
@ -455,7 +455,7 @@
<span class="emphasis"><em>copy 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>
<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">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span> <span class="identifier">def</span> <span class="special">;</span>
<span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span> <span class="identifier">opt</span><span class="special">(</span><span class="identifier">x</span><span class="special">)</span> <span class="special">;</span>
@ -477,7 +477,7 @@
<span class="identifier">rhs</span> <span class="special">)</span>
<span class="special">;</span></code>
</p></blockquote></div>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<span class="bold"><strong>Effect:</strong></span> (Re)binds the wrapped reference.
</li>
@ -486,12 +486,12 @@
same object referenced by <code class="computeroutput"><span class="identifier">rhs</span></code>.
</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, is is <span class="emphasis"><em>rebound</em></span>
<span class="bold"><strong>Notes:</strong></span> If <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> was initialized, it is <span class="emphasis"><em>rebound</em></span>
to the new object. See <a class="link" href="rebinding_semantics_for_assignment_of_optional_references.html" title="Rebinding semantics for assignment of optional references">here</a>
for details on this behavior.
</li>
<li class="listitem">
<span class="bold"><strong>Example:</strong></span>
<span class="bold"><strong>Example:</strong></span>
<pre class="programlisting"><span class="keyword">int</span> <span class="identifier">a</span> <span class="special">=</span> <span class="number">1</span> <span class="special">;</span>
<span class="keyword">int</span> <span class="identifier">b</span> <span class="special">=</span> <span class="number">2</span> <span class="special">;</span>
<span class="identifier">T</span><span class="special">&amp;</span> <span class="identifier">ra</span> <span class="special">=</span> <span class="identifier">a</span> <span class="special">;</span>
@ -499,14 +499,14 @@
<span class="identifier">optional</span><span class="special">&lt;</span><span class="keyword">int</span><span class="special">&amp;&gt;</span> <span class="identifier">def</span> <span class="special">;</span>
<span class="identifier">optional</span><span class="special">&lt;</span><span class="keyword">int</span><span class="special">&amp;&gt;</span> <span class="identifier">opt</span><span class="special">(</span><span class="identifier">ra</span><span class="special">)</span> <span class="special">;</span>
<span class="identifier">def</span> <span class="special">=</span> <span class="identifier">rb</span> <span class="special">;</span> <span class="comment">// binds 'def' to 'b' through 'rb'
</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">b</span> <span class="special">)</span> <span class="special">;</span>
<span class="special">*</span><span class="identifier">def</span> <span class="special">=</span> <span class="identifier">a</span> <span class="special">;</span> <span class="comment">// changes the value of 'b' to a copy of the value of 'a'
</span><span class="identifier">assert</span> <span class="special">(</span> <span class="identifier">b</span> <span class="special">==</span> <span class="identifier">a</span> <span class="special">)</span> <span class="special">;</span>
<span class="identifier">def</span> <span class="special">=</span> <span class="identifier">rb</span> <span class="special">;</span> <span class="comment">// binds 'def' to 'b' through 'rb'</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">b</span> <span class="special">)</span> <span class="special">;</span>
<span class="special">*</span><span class="identifier">def</span> <span class="special">=</span> <span class="identifier">a</span> <span class="special">;</span> <span class="comment">// changes the value of 'b' to a copy of the value of 'a'</span>
<span class="identifier">assert</span> <span class="special">(</span> <span class="identifier">b</span> <span class="special">==</span> <span class="identifier">a</span> <span class="special">)</span> <span class="special">;</span>
<span class="keyword">int</span> <span class="identifier">c</span> <span class="special">=</span> <span class="number">3</span><span class="special">;</span>
<span class="keyword">int</span><span class="special">&amp;</span> <span class="identifier">rc</span> <span class="special">=</span> <span class="identifier">c</span> <span class="special">;</span>
<span class="identifier">opt</span> <span class="special">=</span> <span class="identifier">rc</span> <span class="special">;</span> <span class="comment">// REBINDS to 'c' through 'rc'
</span><span class="identifier">c</span> <span class="special">=</span> <span class="number">4</span> <span class="special">;</span>
<span class="identifier">opt</span> <span class="special">=</span> <span class="identifier">rc</span> <span class="special">;</span> <span class="comment">// REBINDS to 'c' through 'rc'</span>
<span class="identifier">c</span> <span class="special">=</span> <span class="number">4</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="number">4</span> <span class="special">)</span> <span class="special">;</span>
</pre>
</li>
@ -521,7 +521,7 @@
<span class="identifier">rhs</span> <span class="special">)</span>
<span class="special">;</span></code>
</p></blockquote></div>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<span class="bold"><strong>Effect:</strong></span> Assigns another <code class="computeroutput"><span class="identifier">optional</span></code> to an <code class="computeroutput"><span class="identifier">optional</span></code>.
</li>
@ -555,15 +555,15 @@
<span class="emphasis"><em>copy 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>
<span class="bold"><strong>Example:</strong></span>
<pre class="programlisting"><span class="identifier">T</span> <span class="identifier">v</span><span class="special">;</span>
<span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span> <span class="identifier">opt</span><span class="special">(</span><span class="identifier">v</span><span class="special">);</span>
<span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</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="special">!</span><span class="identifier">def</span> <span class="special">)</span> <span class="special">;</span>
<span class="comment">// previous value (copy of 'v') destroyed from within 'opt'.
</span></pre>
<span class="comment">// previous value (copy of 'v') destroyed from within 'opt'.</span>
</pre>
</li>
</ul></div>
<p>
@ -575,7 +575,7 @@
<span class="identifier">rhs</span> <span class="special">)</span>
<span class="special">;</span></code>
</p></blockquote></div>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<span class="bold"><strong>Effect:</strong></span> (Re)binds thee wrapped reference.
</li>
@ -585,12 +585,13 @@
object).
</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 and so is *rhs, this
is is <span class="emphasis"><em>rebound</em></span> to the new object. See <a class="link" href="rebinding_semantics_for_assignment_of_optional_references.html" title="Rebinding semantics for assignment of optional references">here</a>
<span class="bold"><strong>Notes:</strong></span> If <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> was initialized and so is <code class="computeroutput"><span class="special">*</span><span class="identifier">rhs</span></code>,
<code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
is <span class="emphasis"><em>rebound</em></span> to the new object. See <a class="link" href="rebinding_semantics_for_assignment_of_optional_references.html" title="Rebinding semantics for assignment of optional references">here</a>
for details on this behavior.
</li>
<li class="listitem">
<span class="bold"><strong>Example:</strong></span>
<span class="bold"><strong>Example:</strong></span>
<pre class="programlisting"><span class="keyword">int</span> <span class="identifier">a</span> <span class="special">=</span> <span class="number">1</span> <span class="special">;</span>
<span class="keyword">int</span> <span class="identifier">b</span> <span class="special">=</span> <span class="number">2</span> <span class="special">;</span>
<span class="identifier">T</span><span class="special">&amp;</span> <span class="identifier">ra</span> <span class="special">=</span> <span class="identifier">a</span> <span class="special">;</span>
@ -599,15 +600,15 @@
<span class="identifier">optional</span><span class="special">&lt;</span><span class="keyword">int</span><span class="special">&amp;&gt;</span> <span class="identifier">ora</span><span class="special">(</span><span class="identifier">ra</span><span class="special">)</span> <span class="special">;</span>
<span class="identifier">optional</span><span class="special">&lt;</span><span class="keyword">int</span><span class="special">&amp;&gt;</span> <span class="identifier">orb</span><span class="special">(</span><span class="identifier">rb</span><span class="special">)</span> <span class="special">;</span>
<span class="identifier">def</span> <span class="special">=</span> <span class="identifier">orb</span> <span class="special">;</span> <span class="comment">// binds 'def' to 'b' through 'rb' wrapped within 'orb'
</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">b</span> <span class="special">)</span> <span class="special">;</span>
<span class="special">*</span><span class="identifier">def</span> <span class="special">=</span> <span class="identifier">ora</span> <span class="special">;</span> <span class="comment">// changes the value of 'b' to a copy of the value of 'a'
</span><span class="identifier">assert</span> <span class="special">(</span> <span class="identifier">b</span> <span class="special">==</span> <span class="identifier">a</span> <span class="special">)</span> <span class="special">;</span>
<span class="identifier">def</span> <span class="special">=</span> <span class="identifier">orb</span> <span class="special">;</span> <span class="comment">// binds 'def' to 'b' through 'rb' wrapped within 'orb'</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">b</span> <span class="special">)</span> <span class="special">;</span>
<span class="special">*</span><span class="identifier">def</span> <span class="special">=</span> <span class="identifier">ora</span> <span class="special">;</span> <span class="comment">// changes the value of 'b' to a copy of the value of 'a'</span>
<span class="identifier">assert</span> <span class="special">(</span> <span class="identifier">b</span> <span class="special">==</span> <span class="identifier">a</span> <span class="special">)</span> <span class="special">;</span>
<span class="keyword">int</span> <span class="identifier">c</span> <span class="special">=</span> <span class="number">3</span><span class="special">;</span>
<span class="keyword">int</span><span class="special">&amp;</span> <span class="identifier">rc</span> <span class="special">=</span> <span class="identifier">c</span> <span class="special">;</span>
<span class="identifier">optional</span><span class="special">&lt;</span><span class="keyword">int</span><span class="special">&amp;&gt;</span> <span class="identifier">orc</span><span class="special">(</span><span class="identifier">rc</span><span class="special">)</span> <span class="special">;</span>
<span class="identifier">ora</span> <span class="special">=</span> <span class="identifier">orc</span> <span class="special">;</span> <span class="comment">// REBINDS ora to 'c' through 'rc'
</span><span class="identifier">c</span> <span class="special">=</span> <span class="number">4</span> <span class="special">;</span>
<span class="identifier">ora</span> <span class="special">=</span> <span class="identifier">orc</span> <span class="special">;</span> <span class="comment">// REBINDS ora to 'c' through 'rc'</span>
<span class="identifier">c</span> <span class="special">=</span> <span class="number">4</span> <span class="special">;</span>
<span class="identifier">assert</span> <span class="special">(</span> <span class="special">*</span><span class="identifier">ora</span> <span class="special">==</span> <span class="number">4</span> <span class="special">)</span> <span class="special">;</span>
</pre>
</li>
@ -622,7 +623,7 @@
<span class="identifier">rhs</span> <span class="special">)</span>
<span class="special">;</span></code>
</p></blockquote></div>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<span class="bold"><strong>Effect:</strong></span> Assigns another convertible optional
to an optional.
@ -662,7 +663,7 @@
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>
<span class="bold"><strong>Example:</strong></span>
<pre class="programlisting"><span class="identifier">T</span> <span class="identifier">v</span><span class="special">;</span>
<span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</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">&lt;</span><span class="identifier">U</span><span class="special">&gt;</span> <span class="identifier">opt1</span><span class="special">;</span>
@ -687,7 +688,7 @@
<span class="keyword">const</span><span class="special">&amp;</span>
<span class="identifier">f</span> <span class="special">);</span></code>
</p></blockquote></div>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<span class="bold"><strong>Effect:</strong></span> Assigns an <code class="computeroutput"><span class="identifier">optional</span></code>
with a value of <code class="computeroutput"><span class="identifier">T</span></code> obtained
@ -720,7 +721,7 @@
<code class="computeroutput"><span class="keyword">void</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span></code>
<span class="emphasis"><em>(not a ref)</em></span><code class="computeroutput"><span class="special">&gt;::</span><span class="identifier">reset</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></code>
</p></blockquote></div>
<div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem">
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem">
<span class="bold"><strong>Deprecated:</strong></span> same as <code class="computeroutput"><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">&amp;</span>
<span class="identifier">v</span><span class="special">)</span>
@ -732,7 +733,7 @@
<a name="reference_optional_reset"></a><div class="blockquote"><blockquote class="blockquote"><p>
<code class="computeroutput"><span class="keyword">void</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;::</span><span class="identifier">reset</span><span class="special">()</span> <span class="special">;</span></code>
</p></blockquote></div>
<div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem">
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem">
<span class="bold"><strong>Deprecated:</strong></span> Same as <code class="computeroutput"><span class="keyword">operator</span><span class="special">=(</span> <span class="identifier">detail</span><span class="special">::</span><span class="identifier">none_t</span> <span class="special">);</span></code>
</li></ul></div>
<p>
@ -765,7 +766,7 @@
<span class="emphasis"><em>(not a ref)</em></span><code class="computeroutput"><span class="special">&gt;</span>
<span class="special">&amp;)</span> <span class="special">;</span></code>
</p></blockquote></div>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<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
</li>
@ -781,7 +782,7 @@
<code class="computeroutput"><span class="identifier">BOOST_ASSERT</span><span class="special">()</span></code>.
</li>
<li class="listitem">
<span class="bold"><strong>Example:</strong></span>
<span class="bold"><strong>Example:</strong></span>
<pre class="programlisting"><span class="identifier">T</span> <span class="identifier">v</span> <span class="special">;</span>
<span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span> <span class="identifier">opt</span> <span class="special">(</span> <span class="identifier">v</span> <span class="special">);</span>
<span class="identifier">T</span> <span class="keyword">const</span><span class="special">&amp;</span> <span class="identifier">u</span> <span class="special">=</span> <span class="special">*</span><span class="identifier">opt</span><span class="special">;</span>
@ -818,7 +819,7 @@
<span class="emphasis"><em>(not a ref)</em></span><code class="computeroutput"><span class="special">&gt;&amp;</span>
<span class="identifier">o</span><span class="special">,</span> <span class="identifier">T</span><span class="special">&amp;</span> <span class="keyword">default</span> <span class="special">)</span> <span class="special">;</span></code>
</p></blockquote></div>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<span class="bold"><strong>Returns:</strong></span> A reference to the contained
value, if any, or <code class="computeroutput"><span class="keyword">default</span></code>.
@ -827,7 +828,7 @@
<span class="bold"><strong>Throws:</strong></span> Nothing.
</li>
<li class="listitem">
<span class="bold"><strong>Example:</strong></span>
<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">z</span> <span class="special">;</span>
<span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span> <span class="identifier">def</span><span class="special">;</span>
<span class="identifier">T</span> <span class="keyword">const</span><span class="special">&amp;</span> <span class="identifier">y</span> <span class="special">=</span> <span class="identifier">def</span><span class="special">.</span><span class="identifier">get_value_or</span><span class="special">(</span><span class="identifier">z</span><span class="special">);</span>
@ -867,7 +868,7 @@
<code class="computeroutput"><span class="keyword">inline</span> <span class="identifier">T</span><span class="special">&amp;</span> <span class="identifier">get</span> <span class="special">(</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&amp;&gt;</span>
<span class="special">&amp;)</span> <span class="special">;</span></code>
</p></blockquote></div>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<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
</li>
@ -883,7 +884,7 @@
<code class="computeroutput"><span class="identifier">BOOST_ASSERT</span><span class="special">()</span></code>.
</li>
<li class="listitem">
<span class="bold"><strong>Example:</strong></span>
<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">T</span><span class="special">&amp;</span> <span class="identifier">vref</span> <span class="special">=</span> <span class="identifier">v</span> <span class="special">;</span>
<span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&amp;&gt;</span> <span class="identifier">opt</span> <span class="special">(</span> <span class="identifier">vref</span> <span class="special">);</span>
@ -916,7 +917,7 @@
<span class="emphasis"><em>(not a ref)</em></span><code class="computeroutput"><span class="special">&gt;</span>
<span class="special">&amp;)</span> <span class="special">;</span></code>
</p></blockquote></div>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<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 initialized, a pointer to the contained
value; else <code class="computeroutput"><span class="number">0</span></code> (<span class="emphasis"><em>null</em></span>).
@ -930,7 +931,7 @@
so you should not hold nor delete this pointer
</li>
<li class="listitem">
<span class="bold"><strong>Example:</strong></span>
<span class="bold"><strong>Example:</strong></span>
<pre class="programlisting"><span class="identifier">T</span> <span class="identifier">v</span><span class="special">;</span>
<span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span> <span class="identifier">opt</span><span class="special">(</span><span class="identifier">v</span><span class="special">);</span>
<span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span> <span class="keyword">const</span> <span class="identifier">copt</span><span class="special">(</span><span class="identifier">v</span><span class="special">);</span>
@ -953,7 +954,7 @@
<code class="computeroutput"><span class="identifier">T</span><span class="special">*</span>
<span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span></code> <span class="emphasis"><em>(not a ref)</em></span><code class="computeroutput"><span class="special">&gt;::</span><span class="keyword">operator</span> <span class="special">-&gt;()</span> <span class="special">;</span></code>
</p></blockquote></div>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<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.
</li>
@ -968,7 +969,7 @@
<code class="computeroutput"><span class="identifier">BOOST_ASSERT</span><span class="special">()</span></code>.
</li>
<li class="listitem">
<span class="bold"><strong>Example:</strong></span>
<span class="bold"><strong>Example:</strong></span>
<pre class="programlisting"><span class="keyword">struct</span> <span class="identifier">X</span> <span class="special">{</span> <span class="keyword">int</span> <span class="identifier">mdata</span> <span class="special">;</span> <span class="special">}</span> <span class="special">;</span>
<span class="identifier">X</span> <span class="identifier">x</span> <span class="special">;</span>
<span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">X</span><span class="special">&gt;</span> <span class="identifier">opt</span> <span class="special">(</span><span class="identifier">x</span><span class="special">);</span>
@ -982,16 +983,16 @@
<a name="reference_optional_operator_bool"></a><div class="blockquote"><blockquote class="blockquote"><p>
<code class="computeroutput"><span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;::</span><span class="keyword">operator</span> </code><span class="emphasis"><em>unspecified-bool-type</em></span><code class="computeroutput"><span class="special">()</span> <span class="keyword">const</span> <span class="special">;</span></code>
</p></blockquote></div>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<span class="bold"><strong>Returns:</strong></span> An unspecified value which if
used on a boolean context is equivalent to (<code class="computeroutput"><span class="identifier">get</span><span class="special">()</span> <span class="special">!=</span> <span class="number">0</span></code>)
used on a boolean context is equivalent to (<code class="computeroutput"><span class="identifier">get_ptr</span><span class="special">()</span> <span class="special">!=</span> <span class="number">0</span></code>)
</li>
<li class="listitem">
<span class="bold"><strong>Throws:</strong></span> Nothing.
</li>
<li class="listitem">
<span class="bold"><strong>Example:</strong></span>
<span class="bold"><strong>Example:</strong></span>
<pre class="programlisting"><span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</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="number">0</span> <span class="special">);</span>
<span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span> <span class="identifier">opt</span> <span class="special">(</span> <span class="identifier">v</span> <span class="special">)</span> <span class="special">;</span>
@ -1006,7 +1007,7 @@
<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">&lt;</span><span class="identifier">T</span><span class="special">&gt;::</span><span class="keyword">operator</span><span class="special">!()</span> <span class="special">;</span></code>
</p></blockquote></div>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<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>.
@ -1020,13 +1021,13 @@
in certain boolean contexts.
</li>
<li class="listitem">
<span class="bold"><strong>Example:</strong></span>
<span class="bold"><strong>Example:</strong></span>
<pre class="programlisting"><span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span> <span class="identifier">opt</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="special">*</span><span class="identifier">opt</span> <span class="special">=</span> <span class="identifier">some_T</span> <span class="special">;</span>
<span class="comment">// Notice the "double-bang" idiom here.
</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="special">;</span>
<span class="comment">// Notice the "double-bang" idiom here.</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="special">;</span>
</pre>
</li>
</ul></div>
@ -1037,30 +1038,18 @@
<code class="computeroutput"><span class="keyword">bool</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;::</span><span class="identifier">is_initialized</span><span class="special">()</span>
<span class="keyword">const</span> <span class="special">;</span></code>
</p></blockquote></div>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem">
<span class="bold"><strong>Returns: </strong></span> <code class="computeroutput"><span class="keyword">true</span></code>
if the <code class="computeroutput"><span class="identifier">optional</span></code> is initialized,
<code class="computeroutput"><span class="keyword">false</span></code> otherwise.
</li>
<li class="listitem">
<span class="bold"><strong>Throws:</strong></span> Nothing.
</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">T</span><span class="special">&gt;</span> <span class="identifier">def</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">is_initialized</span><span class="special">()</span> <span class="special">);</span>
<span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span> <span class="identifier">opt</span> <span class="special">(</span> <span class="identifier">v</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="identifier">is_initialized</span><span class="special">()</span> <span class="special">);</span>
</pre>
</li>
</ul></div>
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem">
<span class="bold"><strong>Deprecated:</strong></span> Same as <code class="computeroutput"><span class="keyword">operator</span>
</code><span class="emphasis"><em>unspecified-bool-type</em></span><code class="computeroutput"><span class="special">()</span>
<span class="special">;</span></code>
</li></ul></div>
<p>
<span class="inlinemediaobject"><img src="../images/space.png" alt="space"></span>
</p>
<a name="boost_optional.detailed_semantics.free_functions"></a><h4>
<a name="boost_optional.detailed_semantics.free_functions-heading"></a>
<a class="link" href="detailed_semantics.html#boost_optional.detailed_semantics.free_functions">Free functions</a>
<h4>
<a name="boost_optional.detailed_semantics.h1"></a>
<span class="phrase"><a name="boost_optional.detailed_semantics.free_functions"></a></span><a class="link" href="detailed_semantics.html#boost_optional.detailed_semantics.free_functions">Free
functions</a>
</h4>
<p>
<span class="inlinemediaobject"><img src="../images/space.png" alt="space"></span>
@ -1068,17 +1057,17 @@
<a name="reference_make_optional_value"></a><div class="blockquote"><blockquote class="blockquote"><p>
<code class="computeroutput"><span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span></code> <span class="emphasis"><em>(not a ref)</em></span><code class="computeroutput"><span class="special">&gt;</span> <span class="identifier">make_optional</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></code>
</p></blockquote></div>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<span class="bold"><strong>Returns: </strong></span> <code class="computeroutput"><span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;(</span><span class="identifier">v</span><span class="special">)</span></code> for the <span class="emphasis"><em>deduced</em></span> type
<code class="computeroutput"><span class="identifier">T</span></code> of <code class="computeroutput"><span class="identifier">v</span></code>.
</li>
<li class="listitem">
<span class="bold"><strong>Example:</strong></span>
<span class="bold"><strong>Example:</strong></span>
<pre class="programlisting"><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">&gt;</span> <span class="keyword">void</span> <span class="identifier">foo</span> <span class="special">(</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span> <span class="keyword">const</span><span class="special">&amp;</span> <span class="identifier">opt</span> <span class="special">)</span> <span class="special">;</span>
<span class="identifier">foo</span> <span class="special">(</span> <span class="identifier">make_optional</span><span class="special">(</span><span class="number">1</span><span class="special">+</span><span class="number">1</span><span class="special">)</span> <span class="special">)</span> <span class="special">;</span> <span class="comment">// Creates an optional&lt;int&gt;
</span></pre>
<span class="identifier">foo</span> <span class="special">(</span> <span class="identifier">make_optional</span><span class="special">(</span><span class="number">1</span><span class="special">+</span><span class="number">1</span><span class="special">)</span> <span class="special">)</span> <span class="special">;</span> <span class="comment">// Creates an optional&lt;int&gt;</span>
</pre>
</li>
</ul></div>
<p>
@ -1087,14 +1076,14 @@
<a name="reference_make_optional_bool_value"></a><div class="blockquote"><blockquote class="blockquote"><p>
<code class="computeroutput"><span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span></code> <span class="emphasis"><em>(not a ref)</em></span><code class="computeroutput"><span class="special">&gt;</span> <span class="identifier">make_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></code>
</p></blockquote></div>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<span class="bold"><strong>Returns: </strong></span> <code class="computeroutput"><span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;(</span><span class="identifier">condition</span><span class="special">,</span><span class="identifier">v</span><span class="special">)</span></code>
for the <span class="emphasis"><em>deduced</em></span> type <code class="computeroutput"><span class="identifier">T</span></code>
of <code class="computeroutput"><span class="identifier">v</span></code>.
</li>
<li class="listitem">
<span class="bold"><strong>Example:</strong></span>
<span class="bold"><strong>Example:</strong></span>
<pre class="programlisting"><span class="identifier">optional</span><span class="special">&lt;</span><span class="keyword">double</span><span class="special">&gt;</span> <span class="identifier">calculate_foo</span><span class="special">()</span>
<span class="special">{</span>
<span class="keyword">double</span> <span class="identifier">val</span> <span class="special">=</span> <span class="identifier">compute_foo</span><span class="special">();</span>
@ -1116,7 +1105,7 @@
<span class="keyword">const</span><span class="special">&amp;</span>
<span class="identifier">y</span> <span class="special">);</span></code>
</p></blockquote></div>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<span class="bold"><strong>Returns:</strong></span> If both <code class="computeroutput"><span class="identifier">x</span></code>
and <code class="computeroutput"><span class="identifier">y</span></code> are initialized,
@ -1137,7 +1126,7 @@
instead
</li>
<li class="listitem">
<span class="bold"><strong>Example:</strong></span>
<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="number">12</span><span class="special">);</span>
<span class="identifier">T</span> <span class="identifier">y</span><span class="special">(</span><span class="number">12</span><span class="special">);</span>
<span class="identifier">T</span> <span class="identifier">z</span><span class="special">(</span><span class="number">21</span><span class="special">);</span>
@ -1147,18 +1136,18 @@
<span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span> <span class="identifier">optY</span><span class="special">(</span><span class="identifier">y</span><span class="special">);</span>
<span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span> <span class="identifier">optZ</span><span class="special">(</span><span class="identifier">z</span><span class="special">);</span>
<span class="comment">// Identity always hold
</span><span class="identifier">assert</span> <span class="special">(</span> <span class="identifier">def0</span> <span class="special">==</span> <span class="identifier">def0</span> <span class="special">);</span>
<span class="comment">// Identity always hold</span>
<span class="identifier">assert</span> <span class="special">(</span> <span class="identifier">def0</span> <span class="special">==</span> <span class="identifier">def0</span> <span class="special">);</span>
<span class="identifier">assert</span> <span class="special">(</span> <span class="identifier">optX</span> <span class="special">==</span> <span class="identifier">optX</span> <span class="special">);</span>
<span class="comment">// Both uninitialized compare equal
</span><span class="identifier">assert</span> <span class="special">(</span> <span class="identifier">def0</span> <span class="special">==</span> <span class="identifier">def1</span> <span class="special">);</span>
<span class="comment">// Both uninitialized compare equal</span>
<span class="identifier">assert</span> <span class="special">(</span> <span class="identifier">def0</span> <span class="special">==</span> <span class="identifier">def1</span> <span class="special">);</span>
<span class="comment">// Only one initialized compare unequal.
</span><span class="identifier">assert</span> <span class="special">(</span> <span class="identifier">def0</span> <span class="special">!=</span> <span class="identifier">optX</span> <span class="special">);</span>
<span class="comment">// Only one initialized compare unequal.</span>
<span class="identifier">assert</span> <span class="special">(</span> <span class="identifier">def0</span> <span class="special">!=</span> <span class="identifier">optX</span> <span class="special">);</span>
<span class="comment">// Both initialized compare as (*lhs == *rhs)
</span><span class="identifier">assert</span> <span class="special">(</span> <span class="identifier">optX</span> <span class="special">==</span> <span class="identifier">optY</span> <span class="special">)</span> <span class="special">;</span>
<span class="comment">// Both initialized compare as (*lhs == *rhs)</span>
<span class="identifier">assert</span> <span class="special">(</span> <span class="identifier">optX</span> <span class="special">==</span> <span class="identifier">optY</span> <span class="special">)</span> <span class="special">;</span>
<span class="identifier">assert</span> <span class="special">(</span> <span class="identifier">optX</span> <span class="special">!=</span> <span class="identifier">optZ</span> <span class="special">)</span> <span class="special">;</span>
</pre>
</li>
@ -1172,7 +1161,7 @@
<span class="keyword">const</span><span class="special">&amp;</span>
<span class="identifier">y</span> <span class="special">);</span></code>
</p></blockquote></div>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<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="identifier">y</span></code>
is not initialized, <code class="computeroutput"><span class="keyword">false</span></code>.
@ -1194,25 +1183,25 @@
instead.
</li>
<li class="listitem">
<span class="bold"><strong>Example:</strong></span>
<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="number">12</span><span class="special">);</span>
<span class="identifier">T</span> <span class="identifier">y</span><span class="special">(</span><span class="number">34</span><span class="special">);</span>
<span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span> <span class="identifier">def</span> <span class="special">;</span>
<span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span> <span class="identifier">optX</span><span class="special">(</span><span class="identifier">x</span><span class="special">);</span>
<span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span> <span class="identifier">optY</span><span class="special">(</span><span class="identifier">y</span><span class="special">);</span>
<span class="comment">// Identity always hold
</span><span class="identifier">assert</span> <span class="special">(</span> <span class="special">!(</span><span class="identifier">def</span> <span class="special">&lt;</span> <span class="identifier">def</span><span class="special">)</span> <span class="special">);</span>
<span class="comment">// Identity always hold</span>
<span class="identifier">assert</span> <span class="special">(</span> <span class="special">!(</span><span class="identifier">def</span> <span class="special">&lt;</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">optX</span> <span class="special">==</span> <span class="identifier">optX</span> <span class="special">);</span>
<span class="comment">// Both uninitialized compare equal
</span><span class="identifier">assert</span> <span class="special">(</span> <span class="identifier">def0</span> <span class="special">==</span> <span class="identifier">def1</span> <span class="special">);</span>
<span class="comment">// Both uninitialized compare equal</span>
<span class="identifier">assert</span> <span class="special">(</span> <span class="identifier">def0</span> <span class="special">==</span> <span class="identifier">def1</span> <span class="special">);</span>
<span class="comment">// Only one initialized compare unequal.
</span><span class="identifier">assert</span> <span class="special">(</span> <span class="identifier">def0</span> <span class="special">!=</span> <span class="identifier">optX</span> <span class="special">);</span>
<span class="comment">// Only one initialized compare unequal.</span>
<span class="identifier">assert</span> <span class="special">(</span> <span class="identifier">def0</span> <span class="special">!=</span> <span class="identifier">optX</span> <span class="special">);</span>
<span class="comment">// Both initialized compare as (*lhs == *rhs)
</span><span class="identifier">assert</span> <span class="special">(</span> <span class="identifier">optX</span> <span class="special">==</span> <span class="identifier">optY</span> <span class="special">)</span> <span class="special">;</span>
<span class="comment">// Both initialized compare as (*lhs == *rhs)</span>
<span class="identifier">assert</span> <span class="special">(</span> <span class="identifier">optX</span> <span class="special">==</span> <span class="identifier">optY</span> <span class="special">)</span> <span class="special">;</span>
<span class="identifier">assert</span> <span class="special">(</span> <span class="identifier">optX</span> <span class="special">!=</span> <span class="identifier">optZ</span> <span class="special">)</span> <span class="special">;</span>
</pre>
</li>
@ -1226,7 +1215,7 @@
<span class="keyword">const</span><span class="special">&amp;</span>
<span class="identifier">y</span> <span class="special">);</span></code>
</p></blockquote></div>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<span class="bold"><strong>Returns: </strong></span> <code class="computeroutput"><span class="special">!(</span>
<span class="identifier">x</span> <span class="special">==</span>
@ -1245,7 +1234,7 @@
<span class="keyword">const</span><span class="special">&amp;</span>
<span class="identifier">y</span> <span class="special">);</span></code>
</p></blockquote></div>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<span class="bold"><strong>Returns: </strong></span> <code class="computeroutput"><span class="special">(</span>
<span class="identifier">y</span> <span class="special">&lt;</span>
@ -1265,7 +1254,7 @@
<span class="keyword">const</span><span class="special">&amp;</span>
<span class="identifier">y</span> <span class="special">);</span></code>
</p></blockquote></div>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<span class="bold"><strong>Returns: </strong></span> <code class="computeroutput"><span class="special">!(</span>
<span class="identifier">y</span><span class="special">&lt;</span><span class="identifier">x</span> <span class="special">);</span></code>
@ -1284,7 +1273,7 @@
<span class="keyword">const</span><span class="special">&amp;</span>
<span class="identifier">y</span> <span class="special">);</span></code>
</p></blockquote></div>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<span class="bold"><strong>Returns: </strong></span> <code class="computeroutput"><span class="special">!(</span>
<span class="identifier">x</span><span class="special">&lt;</span><span class="identifier">y</span> <span class="special">);</span></code>
@ -1301,7 +1290,7 @@
<span class="special">(</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;&amp;</span>
<span class="identifier">x</span><span class="special">,</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;&amp;</span> <span class="identifier">y</span> <span class="special">);</span></code>
</p></blockquote></div>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<span class="bold"><strong>Effect:</strong></span> If both <code class="computeroutput"><span class="identifier">x</span></code>
and <code class="computeroutput"><span class="identifier">y</span></code> are initialized,
@ -1331,7 +1320,7 @@
If only one is initialized, it has the same basic guarantee as <code class="computeroutput"><span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;::</span><span class="identifier">reset</span><span class="special">(</span> <span class="identifier">T</span> <span class="keyword">const</span><span class="special">&amp;</span> <span class="special">)</span></code>.
</li>
<li class="listitem">
<span class="bold"><strong>Example:</strong></span>
<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="number">12</span><span class="special">);</span>
<span class="identifier">T</span> <span class="identifier">y</span><span class="special">(</span><span class="number">21</span><span class="special">);</span>
<span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span> <span class="identifier">def0</span> <span class="special">;</span>
@ -1339,14 +1328,14 @@
<span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span> <span class="identifier">optX</span><span class="special">(</span><span class="identifier">x</span><span class="special">);</span>
<span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span> <span class="identifier">optY</span><span class="special">(</span><span class="identifier">y</span><span class="special">);</span>
<span class="identifier">boost</span><span class="special">::</span><span class="identifier">swap</span><span class="special">(</span><span class="identifier">def0</span><span class="special">,</span><span class="identifier">def1</span><span class="special">);</span> <span class="comment">// no-op
</span>
<span class="identifier">boost</span><span class="special">::</span><span class="identifier">swap</span><span class="special">(</span><span class="identifier">def0</span><span class="special">,</span><span class="identifier">def1</span><span class="special">);</span> <span class="comment">// no-op</span>
<span class="identifier">boost</span><span class="special">::</span><span class="identifier">swap</span><span class="special">(</span><span class="identifier">def0</span><span class="special">,</span><span class="identifier">optX</span><span class="special">);</span>
<span class="identifier">assert</span> <span class="special">(</span> <span class="special">*</span><span class="identifier">def0</span> <span class="special">==</span> <span class="identifier">x</span> <span class="special">);</span>
<span class="identifier">assert</span> <span class="special">(</span> <span class="special">!</span><span class="identifier">optX</span> <span class="special">);</span>
<span class="identifier">boost</span><span class="special">::</span><span class="identifier">swap</span><span class="special">(</span><span class="identifier">def0</span><span class="special">,</span><span class="identifier">optX</span><span class="special">);</span> <span class="comment">// Get back to original values
</span>
<span class="identifier">boost</span><span class="special">::</span><span class="identifier">swap</span><span class="special">(</span><span class="identifier">def0</span><span class="special">,</span><span class="identifier">optX</span><span class="special">);</span> <span class="comment">// Get back to original values</span>
<span class="identifier">boost</span><span class="special">::</span><span class="identifier">swap</span><span class="special">(</span><span class="identifier">optX</span><span class="special">,</span><span class="identifier">optY</span><span class="special">);</span>
<span class="identifier">assert</span> <span class="special">(</span> <span class="special">*</span><span class="identifier">optX</span> <span class="special">==</span> <span class="identifier">y</span> <span class="special">);</span>
<span class="identifier">assert</span> <span class="special">(</span> <span class="special">*</span><span class="identifier">optY</span> <span class="special">==</span> <span class="identifier">x</span> <span class="special">);</span>

View File

@ -3,7 +3,7 @@
<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
<title>Development</title>
<link rel="stylesheet" href="../boostbook.css" type="text/css">
<meta name="generator" content="DocBook XSL Stylesheets V1.75.2">
<meta name="generator" content="DocBook XSL Stylesheets V1.77.1">
<link rel="home" href="../index.html" title="Chapter&#160;1.&#160;Boost.Optional">
<link rel="up" href="../index.html" title="Chapter&#160;1.&#160;Boost.Optional">
<link rel="prev" href="../index.html" title="Chapter&#160;1.&#160;Boost.Optional">
@ -22,7 +22,7 @@
<div class="spirit-nav">
<a accesskey="p" href="../index.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.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="synopsis.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a>
</div>
<div class="section">
<div class="section boost_optional_development">
<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="boost_optional.development"></a><a class="link" href="development.html" title="Development">Development</a>
</h2></div></div></div>
@ -31,7 +31,7 @@
<dt><span class="section"><a href="development.html#boost_optional.development.the_semantics">The semantics</a></span></dt>
<dt><span class="section"><a href="development.html#boost_optional.development.the_interface">The Interface</a></span></dt>
</dl></div>
<div class="section">
<div class="section boost_optional_development_the_models">
<div class="titlepage"><div><div><h3 class="title">
<a name="boost_optional.development.the_models"></a><a class="link" href="development.html#boost_optional.development.the_models" title="The models">The models</a>
</h3></div></div></div>
@ -110,7 +110,7 @@
<p>
Discriminated-union:
</p>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<span class="bold"><strong>deep-copy</strong></span> semantics: copies of the variant
implies copies of the value.
@ -141,7 +141,7 @@
<p>
Single-element container:
</p>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<span class="bold"><strong>deep-copy</strong></span> semantics: copies of the container
implies copies of the value.
@ -168,7 +168,7 @@
</li>
</ul></div>
</div>
<div class="section">
<div class="section boost_optional_development_the_semantics">
<div class="titlepage"><div><div><h3 class="title">
<a name="boost_optional.development.the_semantics"></a><a class="link" href="development.html#boost_optional.development.the_semantics" title="The semantics">The semantics</a>
</h3></div></div></div>
@ -193,7 +193,7 @@
We can draw from the purpose of <code class="computeroutput"><span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span></code>
the required basic semantics:
</p>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<span class="bold"><strong>Default Construction:</strong></span> To introduce a
formally uninitialized wrapped object.
@ -253,7 +253,7 @@
via a pointer to the wrapped object or null.
</p>
</div>
<div class="section">
<div class="section boost_optional_development_the_interface">
<div class="titlepage"><div><div><h3 class="title">
<a name="boost_optional.development.the_interface"></a><a class="link" href="development.html#boost_optional.development.the_interface" title="The Interface">The Interface</a>
</h3></div></div></div>
@ -292,9 +292,9 @@
operations not provided by <code class="computeroutput"><span class="identifier">T</span></code>
itself which are supported by a special interface.
</p>
<a name="boost_optional.development.the_interface.lexically_hinted_value_access_in_the_presence_of_possibly_untitialized_optional_objects__the_operators___and___gt_"></a><h5>
<a name="boost_optional.development.the_interface.lexically_hinted_value_access_in_the_presence_of_possibly_untitialized_optional_objects__the_operators___and___gt_-heading"></a>
<a class="link" href="development.html#boost_optional.development.the_interface.lexically_hinted_value_access_in_the_presence_of_possibly_untitialized_optional_objects__the_operators___and___gt_">Lexically-hinted
<h5>
<a name="boost_optional.development.the_interface.h0"></a>
<span class="phrase"><a name="boost_optional.development.the_interface.lexically_hinted_value_access_in_the_presence_of_possibly_untitialized_optional_objects__the_operators___and___gt_"></a></span><a class="link" href="development.html#boost_optional.development.the_interface.lexically_hinted_value_access_in_the_presence_of_possibly_untitialized_optional_objects__the_operators___and___gt_">Lexically-hinted
Value Access in the presence of possibly untitialized optional objects: The
operators * and -&gt;</a>
</h5>
@ -357,9 +357,9 @@
possible undefined value because of the idiomatic aid present in the <a href="../../../../utility/OptionalPointee.html" target="_top">OptionalPointee</a> concept
incarnated by pointers.
</p>
<a name="boost_optional.development.the_interface.optional_lt_t_gt__as_a_model_of_optionalpointee"></a><h5>
<a name="boost_optional.development.the_interface.optional_lt_t_gt__as_a_model_of_optionalpointee-heading"></a>
<a class="link" href="development.html#boost_optional.development.the_interface.optional_lt_t_gt__as_a_model_of_optionalpointee">Optional&lt;T&gt;
<h5>
<a name="boost_optional.development.the_interface.h1"></a>
<span class="phrase"><a name="boost_optional.development.the_interface.optional_lt_t_gt__as_a_model_of_optionalpointee"></a></span><a class="link" href="development.html#boost_optional.development.the_interface.optional_lt_t_gt__as_a_model_of_optionalpointee">Optional&lt;T&gt;
as a model of OptionalPointee</a>
</h5>
<p>

View File

@ -3,7 +3,7 @@
<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
<title>Examples</title>
<link rel="stylesheet" href="../boostbook.css" type="text/css">
<meta name="generator" content="DocBook XSL Stylesheets V1.75.2">
<meta name="generator" content="DocBook XSL Stylesheets V1.77.1">
<link rel="home" href="../index.html" title="Chapter&#160;1.&#160;Boost.Optional">
<link rel="up" href="../index.html" title="Chapter&#160;1.&#160;Boost.Optional">
<link rel="prev" href="detailed_semantics.html" title="Detailed Semantics">
@ -22,7 +22,7 @@
<div class="spirit-nav">
<a accesskey="p" href="detailed_semantics.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.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="optional_references.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a>
</div>
<div class="section">
<div class="section boost_optional_examples">
<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="boost_optional.examples"></a><a class="link" href="examples.html" title="Examples">Examples</a>
</h2></div></div></div>
@ -36,7 +36,7 @@
<dt><span class="section"><a href="examples.html#boost_optional.examples.bypassing_expensive_unnecessary_default_construction">Bypassing
expensive unnecessary default construction</a></span></dt>
</dl></div>
<div class="section">
<div class="section boost_optional_examples_optional_return_values">
<div class="titlepage"><div><div><h3 class="title">
<a name="boost_optional.examples.optional_return_values"></a><a class="link" href="examples.html#boost_optional.examples.optional_return_values" title="Optional return values">Optional
return values</a>
@ -45,19 +45,19 @@
<span class="special">{</span>
<span class="keyword">if</span> <span class="special">(</span> <span class="special">!</span><span class="identifier">queue</span><span class="special">.</span><span class="identifier">empty</span><span class="special">()</span> <span class="special">)</span>
<span class="keyword">return</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="keyword">char</span><span class="special">&gt;(</span><span class="identifier">queue</span><span class="special">.</span><span class="identifier">top</span><span class="special">());</span>
<span class="keyword">else</span> <span class="keyword">return</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="keyword">char</span><span class="special">&gt;();</span> <span class="comment">// uninitialized
</span><span class="special">}</span>
<span class="keyword">else</span> <span class="keyword">return</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="keyword">char</span><span class="special">&gt;();</span> <span class="comment">// uninitialized</span>
<span class="special">}</span>
<span class="keyword">void</span> <span class="identifier">receive_async_message</span><span class="special">()</span>
<span class="special">{</span>
<span class="identifier">optional</span><span class="special">&lt;</span><span class="keyword">char</span><span class="special">&gt;</span> <span class="identifier">rcv</span> <span class="special">;</span>
<span class="comment">// The safe boolean conversion from 'rcv' is used here.
</span> <span class="keyword">while</span> <span class="special">(</span> <span class="special">(</span><span class="identifier">rcv</span> <span class="special">=</span> <span class="identifier">get_async_input</span><span class="special">())</span> <span class="special">&amp;&amp;</span> <span class="special">!</span><span class="identifier">timeout</span><span class="special">()</span> <span class="special">)</span>
<span class="comment">// The safe boolean conversion from 'rcv' is used here.</span>
<span class="keyword">while</span> <span class="special">(</span> <span class="special">(</span><span class="identifier">rcv</span> <span class="special">=</span> <span class="identifier">get_async_input</span><span class="special">())</span> <span class="special">&amp;&amp;</span> <span class="special">!</span><span class="identifier">timeout</span><span class="special">()</span> <span class="special">)</span>
<span class="identifier">output</span><span class="special">(*</span><span class="identifier">rcv</span><span class="special">);</span>
<span class="special">}</span>
</pre>
</div>
<div class="section">
<div class="section boost_optional_examples_optional_local_variables">
<div class="titlepage"><div><div><h3 class="title">
<a name="boost_optional.examples.optional_local_variables"></a><a class="link" href="examples.html#boost_optional.examples.optional_local_variables" title="Optional local variables">Optional
local variables</a>
@ -65,12 +65,12 @@
<pre class="programlisting"><span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">string</span><span class="special">&gt;</span> <span class="identifier">name</span> <span class="special">;</span>
<span class="keyword">if</span> <span class="special">(</span> <span class="identifier">database</span><span class="special">.</span><span class="identifier">open</span><span class="special">()</span> <span class="special">)</span>
<span class="special">{</span>
<span class="identifier">name</span><span class="special">.</span><span class="identifier">reset</span> <span class="special">(</span> <span class="identifier">database</span><span class="special">.</span><span class="identifier">lookup</span><span class="special">(</span><span class="identifier">employer_name</span><span class="special">)</span> <span class="special">)</span> <span class="special">;</span>
<span class="identifier">name</span> <span class="special">=</span> <span class="identifier">database</span><span class="special">.</span><span class="identifier">lookup</span><span class="special">(</span><span class="identifier">employer_name</span><span class="special">)</span> <span class="special">;</span>
<span class="special">}</span>
<span class="keyword">else</span>
<span class="special">{</span>
<span class="keyword">if</span> <span class="special">(</span> <span class="identifier">can_ask_user</span> <span class="special">)</span>
<span class="identifier">name</span><span class="special">.</span><span class="identifier">reset</span> <span class="special">(</span> <span class="identifier">user</span><span class="special">.</span><span class="identifier">ask</span><span class="special">(</span><span class="identifier">employer_name</span><span class="special">)</span> <span class="special">)</span> <span class="special">;</span>
<span class="identifier">name</span> <span class="special">=</span> <span class="identifier">user</span><span class="special">.</span><span class="identifier">ask</span><span class="special">(</span><span class="identifier">employer_name</span><span class="special">)</span> <span class="special">;</span>
<span class="special">}</span>
<span class="keyword">if</span> <span class="special">(</span> <span class="identifier">name</span> <span class="special">)</span>
@ -78,7 +78,7 @@
<span class="keyword">else</span> <span class="identifier">print</span><span class="special">(</span><span class="string">"employer's name not found!"</span><span class="special">);</span>
</pre>
</div>
<div class="section">
<div class="section boost_optional_examples_optional_data_members">
<div class="titlepage"><div><div><h3 class="title">
<a name="boost_optional.examples.optional_data_members"></a><a class="link" href="examples.html#boost_optional.examples.optional_data_members" title="Optional data members">Optional
data members</a>
@ -89,14 +89,14 @@
<span class="identifier">figure</span><span class="special">()</span>
<span class="special">{</span>
<span class="comment">// data member 'm_clipping_rect' is uninitialized at this point.
</span> <span class="special">}</span>
<span class="comment">// data member 'm_clipping_rect' is uninitialized at this point.</span>
<span class="special">}</span>
<span class="keyword">void</span> <span class="identifier">clip_in_rect</span> <span class="special">(</span> <span class="identifier">rect</span> <span class="keyword">const</span><span class="special">&amp;</span> <span class="identifier">rect</span> <span class="special">)</span>
<span class="special">{</span>
<span class="special">....</span>
<span class="identifier">m_clipping_rect</span><span class="special">.</span><span class="identifier">reset</span> <span class="special">(</span> <span class="identifier">rect</span> <span class="special">)</span> <span class="special">;</span> <span class="comment">// initialized here.
</span> <span class="special">}</span>
<span class="identifier">m_clipping_rect</span> <span class="special">=</span> <span class="identifier">rect</span> <span class="special">;</span> <span class="comment">// initialized here.</span>
<span class="special">}</span>
<span class="keyword">void</span> <span class="identifier">draw</span> <span class="special">(</span> <span class="identifier">canvas</span><span class="special">&amp;</span> <span class="identifier">cvs</span> <span class="special">)</span>
<span class="special">{</span>
@ -106,8 +106,8 @@
<span class="identifier">cvs</span><span class="special">.</span><span class="identifier">drawXXX</span><span class="special">(..);</span>
<span class="special">}</span>
<span class="comment">// this can return NULL.
</span> <span class="identifier">rect</span> <span class="keyword">const</span><span class="special">*</span> <span class="identifier">get_clipping_rect</span><span class="special">()</span> <span class="special">{</span> <span class="keyword">return</span> <span class="identifier">get_pointer</span><span class="special">(</span><span class="identifier">m_clipping_rect</span><span class="special">);</span> <span class="special">}</span>
<span class="comment">// this can return NULL.</span>
<span class="identifier">rect</span> <span class="keyword">const</span><span class="special">*</span> <span class="identifier">get_clipping_rect</span><span class="special">()</span> <span class="special">{</span> <span class="keyword">return</span> <span class="identifier">get_pointer</span><span class="special">(</span><span class="identifier">m_clipping_rect</span><span class="special">);</span> <span class="special">}</span>
<span class="keyword">private</span> <span class="special">:</span>
@ -116,7 +116,7 @@
<span class="special">};</span>
</pre>
</div>
<div class="section">
<div class="section boost_optional_examples_bypassing_expensive_unnecessary_default_construction">
<div class="titlepage"><div><div><h3 class="title">
<a name="boost_optional.examples.bypassing_expensive_unnecessary_default_construction"></a><a class="link" href="examples.html#boost_optional.examples.bypassing_expensive_unnecessary_default_construction" title="Bypassing expensive unnecessary default construction">Bypassing
expensive unnecessary default construction</a>

View File

@ -3,7 +3,7 @@
<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
<title>Exception Safety Guarantees</title>
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@ -22,7 +22,7 @@
<div class="spirit-nav">
<a accesskey="p" href="a_note_about_optional_bool_.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.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="type_requirements.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a>
</div>
<div class="section">
<div class="section boost_optional_exception_safety_guarantees">
<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="boost_optional.exception_safety_guarantees"></a><a class="link" href="exception_safety_guarantees.html" title="Exception Safety Guarantees">Exception Safety
Guarantees</a>
@ -31,7 +31,7 @@
Because of the current implementation (see <a class="link" href="implementation_notes.html" title="Implementation Notes">Implementation
Notes</a>), all of the assignment methods:
</p>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<code class="computeroutput"><span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;::</span><span class="keyword">operator</span><span class="special">=</span> <span class="special">(</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span> <span class="keyword">const</span><span class="special">&amp;</span> <span class="special">)</span></code>
</li>
@ -52,7 +52,7 @@
<span class="special">)</span> </code>
</li>
<li class="listitem">
<code class="computeroutput"><span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;:::</span><span class="identifier">reset</span> <span class="special">(</span> <span class="identifier">T</span> <span class="keyword">const</span><span class="special">&amp;)</span></code>
<code class="computeroutput"><span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;::</span><span class="identifier">reset</span> <span class="special">(</span> <span class="identifier">T</span> <span class="keyword">const</span><span class="special">&amp;)</span></code>
</li>
</ul></div>
<p>
@ -64,7 +64,7 @@
<p>
On the other hand, the <span class="emphasis"><em>uninitializing</em></span> methods:
</p>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<code class="computeroutput"><span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;::</span><span class="keyword">operator</span><span class="special">=</span> <span class="special">(</span> <span class="identifier">detail</span><span class="special">::</span><span class="identifier">none_t</span> <span class="special">)</span></code>
</li>
@ -84,10 +84,10 @@
know that <code class="computeroutput"><span class="identifier">optional</span></code>'s assignment
and reset has the same guarantees.
</p>
<pre class="programlisting"><span class="comment">//
</span><span class="comment">// Case 1: Exception thrown during assignment.
</span><span class="comment">//
</span><span class="identifier">T</span> <span class="identifier">v0</span><span class="special">(</span><span class="number">123</span><span class="special">);</span>
<pre class="programlisting"><span class="comment">//</span>
<span class="comment">// Case 1: Exception thrown during assignment.</span>
<span class="comment">//</span>
<span class="identifier">T</span> <span class="identifier">v0</span><span class="special">(</span><span class="number">123</span><span class="special">);</span>
<span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span> <span class="identifier">opt0</span><span class="special">(</span><span class="identifier">v0</span><span class="special">);</span>
<span class="keyword">try</span>
<span class="special">{</span>
@ -95,37 +95,37 @@
<span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span> <span class="identifier">opt1</span><span class="special">(</span><span class="identifier">v1</span><span class="special">);</span>
<span class="identifier">opt0</span> <span class="special">=</span> <span class="identifier">opt1</span> <span class="special">;</span>
<span class="comment">// If no exception was thrown, assignment succeeded.
</span> <span class="identifier">assert</span><span class="special">(</span> <span class="special">*</span><span class="identifier">opt0</span> <span class="special">==</span> <span class="identifier">v1</span> <span class="special">)</span> <span class="special">;</span>
<span class="comment">// If no exception was thrown, assignment succeeded.</span>
<span class="identifier">assert</span><span class="special">(</span> <span class="special">*</span><span class="identifier">opt0</span> <span class="special">==</span> <span class="identifier">v1</span> <span class="special">)</span> <span class="special">;</span>
<span class="special">}</span>
<span class="keyword">catch</span><span class="special">(...)</span>
<span class="special">{</span>
<span class="comment">// If any exception was thrown, 'opt0' is reset to uninitialized.
</span> <span class="identifier">assert</span><span class="special">(</span> <span class="special">!</span><span class="identifier">opt0</span> <span class="special">)</span> <span class="special">;</span>
<span class="comment">// If any exception was thrown, 'opt0' is reset to uninitialized.</span>
<span class="identifier">assert</span><span class="special">(</span> <span class="special">!</span><span class="identifier">opt0</span> <span class="special">)</span> <span class="special">;</span>
<span class="special">}</span>
<span class="comment">//
</span><span class="comment">// Case 2: Exception thrown during reset(v)
</span><span class="comment">//
</span><span class="identifier">T</span> <span class="identifier">v0</span><span class="special">(</span><span class="number">123</span><span class="special">);</span>
<span class="comment">//</span>
<span class="comment">// Case 2: Exception thrown during reset(v)</span>
<span class="comment">//</span>
<span class="identifier">T</span> <span class="identifier">v0</span><span class="special">(</span><span class="number">123</span><span class="special">);</span>
<span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span> <span class="identifier">opt</span><span class="special">(</span><span class="identifier">v0</span><span class="special">);</span>
<span class="keyword">try</span>
<span class="special">{</span>
<span class="identifier">T</span> <span class="identifier">v1</span><span class="special">(</span><span class="number">456</span><span class="special">);</span>
<span class="identifier">opt</span><span class="special">.</span><span class="identifier">reset</span> <span class="special">(</span> <span class="identifier">v1</span> <span class="special">)</span> <span class="special">;</span>
<span class="comment">// If no exception was thrown, reset succeeded.
</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">v1</span> <span class="special">)</span> <span class="special">;</span>
<span class="comment">// If no exception was thrown, reset succeeded.</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">v1</span> <span class="special">)</span> <span class="special">;</span>
<span class="special">}</span>
<span class="keyword">catch</span><span class="special">(...)</span>
<span class="special">{</span>
<span class="comment">// If any exception was thrown, 'opt' is reset to uninitialized.
</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="special">;</span>
<span class="comment">// If any exception was thrown, 'opt' is reset to uninitialized.</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="special">;</span>
<span class="special">}</span>
</pre>
<a name="boost_optional.exception_safety_guarantees.swap"></a><h4>
<a name="boost_optional.exception_safety_guarantees.swap-heading"></a>
<a class="link" href="exception_safety_guarantees.html#boost_optional.exception_safety_guarantees.swap">Swap</a>
<h4>
<a name="boost_optional.exception_safety_guarantees.h0"></a>
<span class="phrase"><a name="boost_optional.exception_safety_guarantees.swap"></a></span><a class="link" href="exception_safety_guarantees.html#boost_optional.exception_safety_guarantees.swap">Swap</a>
</h4>
<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">&lt;</span><span class="identifier">T</span><span class="special">&gt;&amp;,</span>

View File

@ -3,7 +3,7 @@
<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
<title>Implementation Notes</title>
<link rel="stylesheet" href="../boostbook.css" type="text/css">
<meta name="generator" content="DocBook XSL Stylesheets V1.75.2">
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<link rel="up" href="../index.html" title="Chapter&#160;1.&#160;Boost.Optional">
<link rel="prev" href="type_requirements.html" title="Type requirements">
@ -22,7 +22,7 @@
<div class="spirit-nav">
<a accesskey="p" href="type_requirements.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.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="dependencies_and_portability.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a>
</div>
<div class="section">
<div class="section boost_optional_implementation_notes">
<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="boost_optional.implementation_notes"></a><a class="link" href="implementation_notes.html" title="Implementation Notes">Implementation Notes</a>
</h2></div></div></div>

View File

@ -3,7 +3,7 @@
<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
<title>In-Place Factories</title>
<link rel="stylesheet" href="../boostbook.css" type="text/css">
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<link rel="prev" href="rebinding_semantics_for_assignment_of_optional_references.html" title="Rebinding semantics for assignment of optional references">
@ -22,7 +22,7 @@
<div class="spirit-nav">
<a accesskey="p" href="rebinding_semantics_for_assignment_of_optional_references.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.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="a_note_about_optional_bool_.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a>
</div>
<div class="section">
<div class="section boost_optional_in_place_factories">
<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="boost_optional.in_place_factories"></a><a class="link" href="in_place_factories.html" title="In-Place Factories">In-Place Factories</a>
</h2></div></div></div>
@ -36,7 +36,7 @@
</p>
<pre class="programlisting"><span class="keyword">struct</span> <span class="identifier">X</span>
<span class="special">{</span>
<span class="identifier">X</span> <span class="special">(</span> <span class="keyword">int</span><span class="special">,</span> <span class="identifier">std</span><span class="special">:::</span><span class="identifier">string</span> <span class="special">)</span> <span class="special">;</span>
<span class="identifier">X</span> <span class="special">(</span> <span class="keyword">int</span><span class="special">,</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span> <span class="special">)</span> <span class="special">;</span>
<span class="special">}</span> <span class="special">;</span>
<span class="keyword">class</span> <span class="identifier">W</span>
@ -50,8 +50,8 @@
<span class="keyword">void</span> <span class="identifier">foo</span><span class="special">()</span>
<span class="special">{</span>
<span class="comment">// Temporary object created.
</span> <span class="identifier">W</span> <span class="special">(</span> <span class="identifier">X</span><span class="special">(</span><span class="number">123</span><span class="special">,</span><span class="string">"hello"</span><span class="special">)</span> <span class="special">)</span> <span class="special">;</span>
<span class="comment">// Temporary object created.</span>
<span class="identifier">W</span> <span class="special">(</span> <span class="identifier">X</span><span class="special">(</span><span class="number">123</span><span class="special">,</span><span class="string">"hello"</span><span class="special">)</span> <span class="special">)</span> <span class="special">;</span>
<span class="special">}</span>
</pre>
<p>
@ -71,9 +71,9 @@
<span class="keyword">void</span> <span class="identifier">foo</span><span class="special">()</span>
<span class="special">{</span>
<span class="comment">// Wrapped object constructed in-place
</span> <span class="comment">// No temporary created.
</span> <span class="identifier">W</span> <span class="special">(</span><span class="number">123</span><span class="special">,</span><span class="string">"hello"</span><span class="special">)</span> <span class="special">;</span>
<span class="comment">// Wrapped object constructed in-place</span>
<span class="comment">// No temporary created.</span>
<span class="identifier">W</span> <span class="special">(</span><span class="number">123</span><span class="special">,</span><span class="string">"hello"</span><span class="special">)</span> <span class="special">;</span>
<span class="special">}</span>
</pre>
<p>
@ -119,15 +119,15 @@
<span class="keyword">void</span> <span class="identifier">foo</span><span class="special">()</span>
<span class="special">{</span>
<span class="comment">// Wrapped object constructed in-place via a TypedInPlaceFactory.
</span> <span class="comment">// No temporary created.
</span> <span class="identifier">W</span> <span class="special">(</span> <span class="identifier">TypedInPlaceFactory2</span><span class="special">&lt;</span><span class="identifier">X</span><span class="special">,</span><span class="keyword">int</span><span class="special">,</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span><span class="special">&gt;(</span><span class="number">123</span><span class="special">,</span><span class="string">"hello"</span><span class="special">))</span> <span class="special">;</span>
<span class="comment">// Wrapped object constructed in-place via a TypedInPlaceFactory.</span>
<span class="comment">// No temporary created.</span>
<span class="identifier">W</span> <span class="special">(</span> <span class="identifier">TypedInPlaceFactory2</span><span class="special">&lt;</span><span class="identifier">X</span><span class="special">,</span><span class="keyword">int</span><span class="special">,</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span><span class="special">&gt;(</span><span class="number">123</span><span class="special">,</span><span class="string">"hello"</span><span class="special">))</span> <span class="special">;</span>
<span class="special">}</span>
</pre>
<p>
The factories are divided in two groups:
</p>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<span class="underline">TypedInPlaceFactories</span>: those which
take the target type as a primary template parameter.
@ -170,9 +170,9 @@
<span class="keyword">void</span> <span class="identifier">foo</span><span class="special">()</span>
<span class="special">{</span>
<span class="comment">// Wrapped object constructed in-place via a InPlaceFactory.
</span> <span class="comment">// No temporary created.
</span> <span class="identifier">W</span> <span class="special">(</span> <span class="identifier">in_place</span><span class="special">(</span><span class="number">123</span><span class="special">,</span><span class="string">"hello"</span><span class="special">)</span> <span class="special">)</span> <span class="special">;</span>
<span class="comment">// Wrapped object constructed in-place via a InPlaceFactory.</span>
<span class="comment">// No temporary created.</span>
<span class="identifier">W</span> <span class="special">(</span> <span class="identifier">in_place</span><span class="special">(</span><span class="number">123</span><span class="special">,</span><span class="string">"hello"</span><span class="special">)</span> <span class="special">)</span> <span class="special">;</span>
<span class="special">}</span>
</pre>
<p>

View File

@ -3,7 +3,7 @@
<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
<title>Optional references</title>
<link rel="stylesheet" href="../boostbook.css" type="text/css">
<meta name="generator" content="DocBook XSL Stylesheets V1.75.2">
<meta name="generator" content="DocBook XSL Stylesheets V1.77.1">
<link rel="home" href="../index.html" title="Chapter&#160;1.&#160;Boost.Optional">
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<link rel="prev" href="examples.html" title="Examples">
@ -22,7 +22,7 @@
<div class="spirit-nav">
<a accesskey="p" href="examples.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.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="rebinding_semantics_for_assignment_of_optional_references.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a>
</div>
<div class="section">
<div class="section boost_optional_optional_references">
<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="boost_optional.optional_references"></a><a class="link" href="optional_references.html" title="Optional references">Optional references</a>
</h2></div></div></div>
@ -35,7 +35,7 @@
However, since references are not real objects some restrictions apply and
some operations are not available in this case:
</p>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
Converting constructors
</li>
@ -57,7 +57,7 @@
treats it wrapped pseudo-object much as a real value, a true real reference
is stored so aliasing will ocurr:
</p>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
Copies of <code class="computeroutput"><span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&amp;&gt;</span></code>
will copy the references but all these references will nonetheless reefer

View File

@ -3,7 +3,7 @@
<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
<title>Rebinding semantics for assignment of optional references</title>
<link rel="stylesheet" href="../boostbook.css" type="text/css">
<meta name="generator" content="DocBook XSL Stylesheets V1.75.2">
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<link rel="prev" href="optional_references.html" title="Optional references">
@ -22,7 +22,7 @@
<div class="spirit-nav">
<a accesskey="p" href="optional_references.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.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="in_place_factories.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a>
</div>
<div class="section">
<div class="section boost_optional_rebinding_semantics_for_assignment_of_optional_references">
<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="boost_optional.rebinding_semantics_for_assignment_of_optional_references"></a><a class="link" href="rebinding_semantics_for_assignment_of_optional_references.html" title="Rebinding semantics for assignment of optional references">Rebinding
semantics for assignment of optional references</a>
@ -36,9 +36,9 @@
<span class="keyword">int</span><span class="special">&amp;</span> <span class="identifier">rx</span> <span class="special">=</span> <span class="identifier">x</span> <span class="special">;</span>
<span class="identifier">optional</span><span class="special">&lt;</span><span class="keyword">int</span><span class="special">&amp;&gt;</span> <span class="identifier">ora</span> <span class="special">;</span>
<span class="identifier">optional</span><span class="special">&lt;</span><span class="keyword">int</span><span class="special">&amp;&gt;</span> <span class="identifier">orb</span><span class="special">(</span><span class="identifier">x</span><span class="special">)</span> <span class="special">;</span>
<span class="identifier">ora</span> <span class="special">=</span> <span class="identifier">orb</span> <span class="special">;</span> <span class="comment">// now 'ora' is bound to 'x' through 'rx'
</span><span class="special">*</span><span class="identifier">ora</span> <span class="special">=</span> <span class="number">2</span> <span class="special">;</span> <span class="comment">// Changes value of 'x' through 'ora'
</span><span class="identifier">assert</span><span class="special">(</span><span class="identifier">x</span><span class="special">==</span><span class="number">2</span><span class="special">);</span>
<span class="identifier">ora</span> <span class="special">=</span> <span class="identifier">orb</span> <span class="special">;</span> <span class="comment">// now 'ora' is bound to 'x' through 'rx'</span>
<span class="special">*</span><span class="identifier">ora</span> <span class="special">=</span> <span class="number">2</span> <span class="special">;</span> <span class="comment">// Changes value of 'x' through 'ora'</span>
<span class="identifier">assert</span><span class="special">(</span><span class="identifier">x</span><span class="special">==</span><span class="number">2</span><span class="special">);</span>
</pre>
<p>
If you assign to a bare C++ reference, the assignment is forwarded to the referenced
@ -48,11 +48,11 @@
<span class="keyword">int</span><span class="special">&amp;</span> <span class="identifier">ra</span> <span class="special">=</span> <span class="identifier">a</span> <span class="special">;</span>
<span class="keyword">int</span> <span class="identifier">b</span> <span class="special">=</span> <span class="number">2</span> <span class="special">;</span>
<span class="keyword">int</span><span class="special">&amp;</span> <span class="identifier">rb</span> <span class="special">=</span> <span class="identifier">b</span> <span class="special">;</span>
<span class="identifier">ra</span> <span class="special">=</span> <span class="identifier">rb</span> <span class="special">;</span> <span class="comment">// Changes the value of 'a' to 'b'
</span><span class="identifier">assert</span><span class="special">(</span><span class="identifier">a</span><span class="special">==</span><span class="identifier">b</span><span class="special">);</span>
<span class="identifier">ra</span> <span class="special">=</span> <span class="identifier">rb</span> <span class="special">;</span> <span class="comment">// Changes the value of 'a' to 'b'</span>
<span class="identifier">assert</span><span class="special">(</span><span class="identifier">a</span><span class="special">==</span><span class="identifier">b</span><span class="special">);</span>
<span class="identifier">b</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="identifier">ra</span><span class="special">!=</span><span class="identifier">b</span><span class="special">);</span> <span class="comment">// 'ra' is not rebound to 'b'
</span></pre>
<span class="identifier">assert</span><span class="special">(</span><span class="identifier">ra</span><span class="special">!=</span><span class="identifier">b</span><span class="special">);</span> <span class="comment">// 'ra' is not rebound to 'b'</span>
</pre>
<p>
Now, if you assign to an <span class="emphasis"><em>initialized </em></span> <code class="computeroutput"><span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&amp;&gt;</span></code>,
the effect is to <span class="bold"><strong>rebind</strong></span> to the new object
@ -64,14 +64,14 @@
<span class="keyword">int</span><span class="special">&amp;</span> <span class="identifier">rb</span> <span class="special">=</span> <span class="identifier">b</span> <span class="special">;</span>
<span class="identifier">optional</span><span class="special">&lt;</span><span class="keyword">int</span><span class="special">&amp;&gt;</span> <span class="identifier">ora</span><span class="special">(</span><span class="identifier">ra</span><span class="special">)</span> <span class="special">;</span>
<span class="identifier">optional</span><span class="special">&lt;</span><span class="keyword">int</span><span class="special">&amp;&gt;</span> <span class="identifier">orb</span><span class="special">(</span><span class="identifier">rb</span><span class="special">)</span> <span class="special">;</span>
<span class="identifier">ora</span> <span class="special">=</span> <span class="identifier">orb</span> <span class="special">;</span> <span class="comment">// 'ora' is rebound to 'b'
</span><span class="special">*</span><span class="identifier">ora</span> <span class="special">=</span> <span class="number">3</span> <span class="special">;</span> <span class="comment">// Changes value of 'b' (not 'a')
</span><span class="identifier">assert</span><span class="special">(</span><span class="identifier">a</span><span class="special">==</span><span class="number">1</span><span class="special">);</span>
<span class="identifier">assert</span><span class="special">(</span><span class="identifier">b</span><span class="special">==</span><span class="number">3</span><span class="special">);</span>
<span class="identifier">ora</span> <span class="special">=</span> <span class="identifier">orb</span> <span class="special">;</span> <span class="comment">// 'ora' is rebound to 'b'</span>
<span class="special">*</span><span class="identifier">ora</span> <span class="special">=</span> <span class="number">3</span> <span class="special">;</span> <span class="comment">// Changes value of 'b' (not 'a')</span>
<span class="identifier">assert</span><span class="special">(</span><span class="identifier">a</span><span class="special">==</span><span class="number">1</span><span class="special">);</span>
<span class="identifier">assert</span><span class="special">(</span><span class="identifier">b</span><span class="special">==</span><span class="number">3</span><span class="special">);</span>
</pre>
<a name="boost_optional.rebinding_semantics_for_assignment_of_optional_references.rationale"></a><h4>
<a name="boost_optional.rebinding_semantics_for_assignment_of_optional_references.rationale-heading"></a>
<a class="link" href="rebinding_semantics_for_assignment_of_optional_references.html#boost_optional.rebinding_semantics_for_assignment_of_optional_references.rationale">Rationale</a>
<h4>
<a name="boost_optional.rebinding_semantics_for_assignment_of_optional_references.h0"></a>
<span class="phrase"><a name="boost_optional.rebinding_semantics_for_assignment_of_optional_references.rationale"></a></span><a class="link" href="rebinding_semantics_for_assignment_of_optional_references.html#boost_optional.rebinding_semantics_for_assignment_of_optional_references.rationale">Rationale</a>
</h4>
<p>
Rebinding semantics for the assignment of <span class="emphasis"><em>initialized </em></span>

View File

@ -3,7 +3,7 @@
<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
<title>Synopsis</title>
<link rel="stylesheet" href="../boostbook.css" type="text/css">
<meta name="generator" content="DocBook XSL Stylesheets V1.75.2">
<meta name="generator" content="DocBook XSL Stylesheets V1.77.1">
<link rel="home" href="../index.html" title="Chapter&#160;1.&#160;Boost.Optional">
<link rel="up" href="../index.html" title="Chapter&#160;1.&#160;Boost.Optional">
<link rel="prev" href="development.html" title="Development">
@ -22,7 +22,7 @@
<div class="spirit-nav">
<a accesskey="p" href="development.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.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="detailed_semantics.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a>
</div>
<div class="section">
<div class="section boost_optional_synopsis">
<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="boost_optional.synopsis"></a><a class="link" href="synopsis.html" title="Synopsis">Synopsis</a>
</h2></div></div></div>
@ -35,16 +35,16 @@
<span class="special">{</span>
<span class="keyword">public</span> <span class="special">:</span>
<span class="comment">// (If T is of reference type, the parameters and results by reference are by value)
</span>
<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="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">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.html#reference_optional_constructor_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.html#reference_optional_constructor_bool_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.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.html#reference_optional_constructor_optional"><span class="inlinemediaobject"><img src="../images/callouts/R.png" alt="R"></span></a>
@ -54,7 +54,7 @@
<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.html#reference_optional_constructor_factory"><span class="inlinemediaobject"><img src="../images/callouts/R.png" alt="R"></span></a>
<span class="identifier">optional</span><span class="special">&amp;</span> <span class="keyword">operator</span> <span class="special">=</span> <span class="special">(</span> <span class="identifier">none_t</span> <span class="special">)</span> <span class="special">;</span>
<span class="identifier">optional</span><span class="special">&amp;</span> <span class="keyword">operator</span> <span class="special">=</span> <span class="special">(</span> <span class="identifier">none_t</span> <span class="special">)</span> <span class="special">;</span>
<span class="identifier">optional</span><span class="special">&amp;</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">&amp;</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>
@ -69,8 +69,8 @@
<span class="identifier">T</span> <span class="keyword">const</span><span class="special">&amp;</span> <span class="identifier">get</span><span class="special">()</span> <span class="keyword">const</span> <span class="special">;</span> <a class="link" href="detailed_semantics.html#reference_optional_get"><span class="inlinemediaobject"><img src="../images/callouts/R.png" alt="R"></span></a>
<span class="identifier">T</span><span class="special">&amp;</span> <span class="identifier">get</span><span class="special">()</span> <span class="special">;</span> <a class="link" href="detailed_semantics.html#reference_optional_get"><span class="inlinemediaobject"><img src="../images/callouts/R.png" alt="R"></span></a>
<span class="comment">// [new in 1.34]
</span> <span class="identifier">T</span> <span class="keyword">const</span><span class="special">&amp;</span> <span class="identifier">get_value_or</span><span class="special">(</span> <span class="identifier">T</span> <span class="keyword">const</span><span class="special">&amp;</span> <span class="keyword">default</span> <span class="special">)</span> <span class="keyword">const</span> <span class="special">;</span> <a class="link" href="detailed_semantics.html#reference_optional_get_value_or_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">T</span> <span class="keyword">const</span><span class="special">&amp;</span> <span class="identifier">get_value_or</span><span class="special">(</span> <span class="identifier">T</span> <span class="keyword">const</span><span class="special">&amp;</span> <span class="keyword">default</span> <span class="special">)</span> <span class="keyword">const</span> <span class="special">;</span> <a class="link" href="detailed_semantics.html#reference_optional_get_value_or_value"><span class="inlinemediaobject"><img src="../images/callouts/R.png" alt="R"></span></a>
<span class="identifier">T</span> <span class="keyword">const</span><span class="special">*</span> <span class="keyword">operator</span> <span class="special">-&gt;()</span> <span class="keyword">const</span> <span class="special">;</span> <a class="link" href="detailed_semantics.html#reference_optional_operator_arrow"><span class="inlinemediaobject"><img src="../images/callouts/R.png" alt="R"></span></a>
<span class="identifier">T</span><span class="special">*</span> <span class="keyword">operator</span> <span class="special">-&gt;()</span> <span class="special">;</span> <a class="link" href="detailed_semantics.html#reference_optional_operator_arrow"><span class="inlinemediaobject"><img src="../images/callouts/R.png" alt="R"></span></a>
@ -85,16 +85,16 @@
<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="comment">// deprecated methods
</span>
<span class="comment">// (deprecated)
</span> <span class="keyword">void</span> <span class="identifier">reset</span><span class="special">()</span> <span class="special">;</span> <a class="link" href="detailed_semantics.html#reference_optional_reset"><span class="inlinemediaobject"><img src="../images/callouts/R.png" alt="R"></span></a>
<span class="comment">// deprecated methods</span>
<span class="comment">// (deprecated)
</span> <span class="keyword">void</span> <span class="identifier">reset</span> <span class="special">(</span> <span class="identifier">T</span> <span class="keyword">const</span><span class="special">&amp;</span> <span class="special">)</span> <span class="special">;</span> <a class="link" href="detailed_semantics.html#reference_optional_reset_value"><span class="inlinemediaobject"><img src="../images/callouts/R.png" alt="R"></span></a>
<span class="comment">// (deprecated)</span>
<span class="keyword">void</span> <span class="identifier">reset</span><span class="special">()</span> <span class="special">;</span> <a class="link" href="detailed_semantics.html#reference_optional_reset"><span class="inlinemediaobject"><img src="../images/callouts/R.png" alt="R"></span></a>
<span class="comment">// (deprecated)
</span> <span class="keyword">bool</span> <span class="identifier">is_initialized</span><span class="special">()</span> <span class="keyword">const</span> <span class="special">;</span> <a class="link" href="detailed_semantics.html#reference_optional_is_initialized"><span class="inlinemediaobject"><img src="../images/callouts/R.png" alt="R"></span></a>
<span class="comment">// (deprecated)</span>
<span class="keyword">void</span> <span class="identifier">reset</span> <span class="special">(</span> <span class="identifier">T</span> <span class="keyword">const</span><span class="special">&amp;</span> <span class="special">)</span> <span class="special">;</span> <a class="link" href="detailed_semantics.html#reference_optional_reset_value"><span class="inlinemediaobject"><img src="../images/callouts/R.png" alt="R"></span></a>
<span class="comment">// (deprecated)</span>
<span class="keyword">bool</span> <span class="identifier">is_initialized</span><span class="special">()</span> <span class="keyword">const</span> <span class="special">;</span> <a class="link" href="detailed_semantics.html#reference_optional_is_initialized"><span class="inlinemediaobject"><img src="../images/callouts/R.png" alt="R"></span></a>
<span class="special">};</span>
@ -110,14 +110,14 @@
<span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">&gt;</span> <span class="keyword">inline</span> <span class="keyword">bool</span> <span class="keyword">operator</span> <span class="special">&gt;=</span> <span class="special">(</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span> <span class="keyword">const</span><span class="special">&amp;</span> <span class="identifier">x</span><span class="special">,</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span> <span class="keyword">const</span><span class="special">&amp;</span> <span class="identifier">y</span> <span class="special">)</span> <span class="special">;</span> <a class="link" href="detailed_semantics.html#reference_operator_compare_greater_or_equal_optional_optional"><span class="inlinemediaobject"><img src="../images/callouts/R.png" alt="R"></span></a>
<span class="comment">// [new in 1.34]
</span><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">&gt;</span> <span class="keyword">inline</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span> <span class="identifier">make_optional</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.html#reference_make_optional_value"><span class="inlinemediaobject"><img src="../images/callouts/R.png" alt="R"></span></a>
<span class="comment">// [new in 1.34]</span>
<span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">&gt;</span> <span class="keyword">inline</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span> <span class="identifier">make_optional</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.html#reference_make_optional_value"><span class="inlinemediaobject"><img src="../images/callouts/R.png" alt="R"></span></a>
<span class="comment">// [new in 1.34]
</span><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">&gt;</span> <span class="keyword">inline</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span> <span class="identifier">make_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.html#reference_make_optional_bool_value"><span class="inlinemediaobject"><img src="../images/callouts/R.png" alt="R"></span></a>
<span class="comment">// [new in 1.34]</span>
<span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">&gt;</span> <span class="keyword">inline</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span> <span class="identifier">make_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.html#reference_make_optional_bool_value"><span class="inlinemediaobject"><img src="../images/callouts/R.png" alt="R"></span></a>
<span class="comment">// [new in 1.34]
</span><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">&gt;</span> <span class="keyword">inline</span> <span class="identifier">T</span> <span class="keyword">const</span><span class="special">&amp;</span> <span class="identifier">get_optional_value_or</span> <span class="special">(</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span> <span class="keyword">const</span><span class="special">&amp;</span> <span class="identifier">opt</span><span class="special">,</span> <span class="identifier">T</span> <span class="keyword">const</span><span class="special">&amp;</span> <span class="keyword">default</span> <span class="special">)</span> <span class="special">;</span> <a class="link" href="detailed_semantics.html#reference_optional_get_value_or_value"><span class="inlinemediaobject"><img src="../images/callouts/R.png" alt="R"></span></a>
<span class="comment">// [new in 1.34]</span>
<span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">&gt;</span> <span class="keyword">inline</span> <span class="identifier">T</span> <span class="keyword">const</span><span class="special">&amp;</span> <span class="identifier">get_optional_value_or</span> <span class="special">(</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span> <span class="keyword">const</span><span class="special">&amp;</span> <span class="identifier">opt</span><span class="special">,</span> <span class="identifier">T</span> <span class="keyword">const</span><span class="special">&amp;</span> <span class="keyword">default</span> <span class="special">)</span> <span class="special">;</span> <a class="link" href="detailed_semantics.html#reference_optional_get_value_or_value"><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">T</span><span class="special">&gt;</span> <span class="keyword">inline</span> <span class="identifier">T</span> <span class="keyword">const</span><span class="special">&amp;</span> <span class="identifier">get</span> <span class="special">(</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span> <span class="keyword">const</span><span class="special">&amp;</span> <span class="identifier">opt</span> <span class="special">)</span> <span class="special">;</span> <a class="link" href="detailed_semantics.html#reference_optional_get"><span class="inlinemediaobject"><img src="../images/callouts/R.png" alt="R"></span></a>
@ -133,8 +133,8 @@
<span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">&gt;</span> <span class="keyword">inline</span> <span class="keyword">void</span> <span class="identifier">swap</span><span class="special">(</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;&amp;</span> <span class="identifier">x</span><span class="special">,</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;&amp;</span> <span class="identifier">y</span> <span class="special">)</span> <span class="special">;</span> <a class="link" href="detailed_semantics.html#reference_swap_optional_optional"><span class="inlinemediaobject"><img src="../images/callouts/R.png" alt="R"></span></a>
<span class="special">}</span> <span class="comment">// namespace boost
</span></pre>
<span class="special">}</span> <span class="comment">// namespace boost</span>
</pre>
</div>
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@ -3,7 +3,7 @@
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<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="boost_optional.type_requirements"></a><a class="link" href="type_requirements.html" title="Type requirements">Type requirements</a>
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@ -3,7 +3,7 @@
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@ -27,7 +27,7 @@
</h3></div></div>
<div><p class="copyright">Copyright &#169; 2003-2007 Fernando Luis Cacciola Carballal</p></div>
<div><div class="legalnotice">
<a name="id2833979"></a><p>
<a name="optional.legal"></a><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>
@ -71,7 +71,7 @@
<dt><span class="section"><a href="boost_optional/acknowledgments.html">Acknowledgments</a></span></dt>
</dl>
</div>
<div class="section">
<div class="section optional_motivation">
<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="optional.motivation"></a><a class="link" href="index.html#optional.motivation" title="Motivation">Motivation</a>
</h2></div></div></div>
@ -79,7 +79,7 @@
Consider these functions which should return a value but which might not have
a value to return:
</p>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
(A) <code class="computeroutput"><span class="keyword">double</span> <span class="identifier">sqrt</span><span class="special">(</span><span class="keyword">double</span> <span class="identifier">n</span> <span class="special">);</span></code>
</li>
@ -163,7 +163,7 @@
</div>
</div>
<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
<td align="left"><p><small>Last revised: April 07, 2011 at 21:02:08 GMT</small></p></td>
<td align="left"><p><small>Last revised: February 16, 2013 at 19:42:23 GMT</small></p></td>
<td align="right"><div class="copyright-footer"></div></td>
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@ -386,7 +386,7 @@ __SPACE__
* [*Effect:] (Re)binds the wrapped reference.
* [*Postconditions: ] `*this` is initialized and it references the same
object referenced by `rhs`.
* [*Notes:] If `*this` was initialized, is is ['rebound] to the new object.
* [*Notes:] If `*this` was initialized, it is ['rebound] to the new object.
See [link boost_optional.rebinding_semantics_for_assignment_of_optional_references here] for details on this behavior.
* [*Example:]
``
@ -445,7 +445,7 @@ __SPACE__
* [*Postconditions:] If `*rhs` is initialized, `*this` is initialized and it
references the same object referenced by `*rhs`; otherwise, `*this` is
uninitialized (and references no object).
* [*Notes:] If `*this` was initialized and so is *rhs, this is is ['rebound] to
* [*Notes:] If `*this` was initialized and so is `*rhs`, `*this` is ['rebound] to
the new object. See [link boost_optional.rebinding_semantics_for_assignment_of_optional_references here] for details on this behavior.
* [*Example:]
``
@ -660,7 +660,7 @@ __SPACE__
[: `optional<T>::operator `['unspecified-bool-type]`() const ;`]
* [*Returns:] An unspecified value which if used on a boolean context
is equivalent to (`get() != 0`)
is equivalent to (`get_ptr() != 0`)
* [*Throws:] Nothing.
* [*Example:]
``
@ -697,15 +697,7 @@ __SPACE__
[: `bool optional<T>::is_initialized() const ;`]
* [*Returns: ] `true` if the `optional` is initialized, `false` otherwise.
* [*Throws:] Nothing.
* [*Example:]
``
optional<T> def ;
assert ( !def.is_initialized() );
optional<T> opt ( v ) ;
assert ( opt.is_initialized() );
``
* [*Deprecated:] Same as `operator `['unspecified-bool-type]`() ;`
__SPACE__

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@ -120,7 +120,7 @@ a fully constructed object, often temporary, just to follow the copy from:
struct X
{
X ( int, std:::string ) ;
X ( int, std::string ) ;
} ;
class W
@ -291,7 +291,7 @@ Because of the current implementation (see [link boost_optional.implementation_n
* `template<class U> optional<T>::operator= ( optional<U> const& )`
* `template<class InPlaceFactory> optional<T>::operator= ( InPlaceFactory const& )`
* `template<class TypedInPlaceFactory> optional<T>::operator= ( TypedInPlaceFactory const& ) `
* `optional<T>:::reset ( T const&)`
* `optional<T>::reset ( T const&)`
Can only ['guarantee] the [_basic exception safety]: The lvalue optional is
left [_uninitialized] if an exception is thrown (any previous value is ['first]

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@ -17,6 +17,7 @@
#include <new>
#include <algorithm>
#include <iosfwd>
#include <boost/config.hpp>
#include <boost/assert.hpp>
@ -127,7 +128,7 @@ class aligned_storage
union
// This works around GCC warnings about breaking strict aliasing rules when casting storage address to T*
#if defined(BOOST_OPTIONAL_DETAIL_USE_ATTRIBUTE_MAY_ALIAS)
__attribute__((may_alias))
__attribute__((__may_alias__))
#endif
dummy_u
{
@ -476,7 +477,7 @@ class optional_base : public optional_tag
#if BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x581))
void destroy_impl ( is_not_reference_tag ) { get_ptr_impl()->internal_type::~internal_type() ; m_initialized = false ; }
#else
void destroy_impl ( is_not_reference_tag ) { get_ptr_impl()->T::~T() ; m_initialized = false ; }
void destroy_impl ( is_not_reference_tag ) { get_ptr_impl()->~T() ; m_initialized = false ; }
#endif
void destroy_impl ( is_reference_tag ) { m_initialized = false ; }
@ -743,6 +744,11 @@ get_pointer ( optional<T>& opt )
return opt.get_ptr() ;
}
// Forward declaration to prevent operator safe-bool from being used.
template<class CharType, class CharTrait, class T>
std::basic_ostream<CharType, CharTrait>&
operator<<(std::basic_ostream<CharType, CharTrait>& out, optional<T> const& v);
// optional's relational operators ( ==, !=, <, >, <=, >= ) have deep-semantics (compare values).
// WARNING: This is UNLIKE pointers. Use equal_pointees()/less_pointess() in generic code instead.
@ -890,12 +896,12 @@ bool operator >= ( optional<T> const& x, none_t y )
template<class T>
inline
bool operator == ( none_t x, optional<T> const& y )
bool operator == ( none_t , optional<T> const& y )
{ return equal_pointees(optional<T>() ,y); }
template<class T>
inline
bool operator < ( none_t x, optional<T> const& y )
bool operator < ( none_t , optional<T> const& y )
{ return less_pointees(optional<T>() ,y); }
template<class T>

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@ -840,11 +840,21 @@ void test_with_builtin_types()
test_none( ARG(double) ) ;
}
// MSVC < 11.0 doesn't destroy X when we call ptr->VBase::VBase.
// Make sure that we work around this bug.
struct VBase : virtual X
{
VBase(int v) : X(v) {}
// MSVC 8.0 doesn't generate this correctly...
VBase(const VBase& other) : X(static_cast<const X&>(other)) {}
};
void test_with_class_type()
{
TRACE( std::endl << BOOST_CURRENT_FUNCTION );
test_basics( ARG(X) );
test_basics( ARG(VBase) );
test_conditional_ctor_and_get_valur_or( ARG(X) );
test_direct_value_manip( ARG(X) );
test_uninitialized_access( ARG(X) );