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| Author | SHA1 | Date | |
|---|---|---|---|
| da8f2d028e |
@ -24,7 +24,7 @@ boostbook standalone
|
||||
optional
|
||||
:
|
||||
<xsl:param>boost.root=../../../..
|
||||
<xsl:param>html.stylesheet=boostbook.css
|
||||
<xsl:param>boost.libraries=../../../libraries.htm
|
||||
<xsl:param>toc.max.depth=2
|
||||
<xsl:param>toc.section.depth=2
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||||
<xsl:param>chunk.section.depth=1
|
||||
|
||||
@ -1,4 +1,4 @@
|
||||
[/
|
||||
[/
|
||||
Boost.Optional
|
||||
|
||||
Copyright (c) 2003-2007 Fernando Luis Cacciola Carballal
|
||||
@ -58,7 +58,7 @@ The observation made in the last paragraph about the irrelevant nature of the
|
||||
additional `nil_t` with respect to [_purpose] of `optional<T>` suggests an
|
||||
alternative model: a ['container] that either has a value of `T` or nothing.
|
||||
|
||||
As of this writing I don't know of any precedent for a variable-size
|
||||
As of this writing I don't know of any precedence for a variable-size
|
||||
fixed-capacity (of 1) stack-based container model for optional values, yet I
|
||||
believe this is the consequence of the lack of practical implementations of
|
||||
such a container rather than an inherent shortcoming of the container model.
|
||||
@ -176,14 +176,14 @@ untitialized optional objects: The operators * and ->]
|
||||
A relevant feature of a pointer is that it can have a [*null pointer value].
|
||||
This is a ['special] value which is used to indicate that the pointer is not
|
||||
referring to any object at all. In other words, null pointer values convey
|
||||
the notion of nonexistent objects.
|
||||
the notion of inexistent objects.
|
||||
|
||||
This meaning of the null pointer value allowed pointers to became a ['de
|
||||
facto] standard for handling optional objects because all you have to do
|
||||
to refer to a value which you don't really have is to use a null pointer
|
||||
value of the appropriate type. Pointers have been used for decades—from
|
||||
the days of C APIs to modern C++ libraries—to ['refer] to optional (that is,
|
||||
possibly nonexistent) objects; particularly as optional arguments to a
|
||||
possibly inexistent) objects; particularly as optional arguments to a
|
||||
function, but also quite often as optional data members.
|
||||
|
||||
The possible presence of a null pointer value makes the operations that
|
||||
|
||||
@ -35,12 +35,12 @@
|
||||
optional<string> name ;
|
||||
if ( database.open() )
|
||||
{
|
||||
name = database.lookup(employer_name) ;
|
||||
name.reset ( database.lookup(employer_name) ) ;
|
||||
}
|
||||
else
|
||||
{
|
||||
if ( can_ask_user )
|
||||
name = user.ask(employer_name) ;
|
||||
name.reset ( user.ask(employer_name) ) ;
|
||||
}
|
||||
|
||||
if ( name )
|
||||
@ -63,7 +63,7 @@
|
||||
void clip_in_rect ( rect const& rect )
|
||||
{
|
||||
....
|
||||
m_clipping_rect = rect ; // initialized here.
|
||||
m_clipping_rect.reset ( rect ) ; // initialized here.
|
||||
}
|
||||
|
||||
void draw ( canvas& cvs )
|
||||
|
||||
@ -1,11 +1,11 @@
|
||||
<html>
|
||||
<head>
|
||||
<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
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||||
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
|
||||
<title>A note about optional<bool></title>
|
||||
<link rel="stylesheet" href="../boostbook.css" type="text/css">
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<meta name="generator" content="DocBook XSL Stylesheets V1.77.1">
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<link rel="home" href="../index.html" title="Chapter 1. Boost.Optional">
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<link rel="next" href="exception_safety_guarantees.html" title="Exception Safety Guarantees">
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||||
</head>
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||||
@ -13,16 +13,16 @@
|
||||
<table cellpadding="2" width="100%"><tr>
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||||
<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../boost.png"></td>
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<td align="center"><a href="../../../../../index.html">Home</a></td>
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<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td>
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<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td>
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||||
</div>
|
||||
<div class="section boost_optional_a_note_about_optional_bool_">
|
||||
<div class="section" title="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<bool>">A note about
|
||||
optional<bool></a>
|
||||
@ -54,11 +54,11 @@
|
||||
<span class="special">{</span>
|
||||
<span class="identifier">optional</span><span class="special"><</span><span class="keyword">bool</span><span class="special">></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>,
|
||||
@ -70,7 +70,7 @@
|
||||
</div>
|
||||
<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
|
||||
<td align="left"></td>
|
||||
<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<p>
|
||||
<td align="right"><div class="copyright-footer">Copyright <EFBFBD> 2003 -2007 Fernando Luis Cacciola Carballal<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>
|
||||
@ -78,7 +78,7 @@
|
||||
</tr></table>
|
||||
<hr>
|
||||
<div class="spirit-nav">
|
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<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>
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<a accesskey="p" href="in_place_factories.html"><img src="../../../../../doc/html/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.html"><img src="../../../../../doc/html/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../../../doc/html/images/home.png" alt="Home"></a><a accesskey="n" href="exception_safety_guarantees.html"><img src="../../../../../doc/html/images/next.png" alt="Next"></a>
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</div>
|
||||
</body>
|
||||
</html>
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||||
|
||||
@ -1,43 +1,43 @@
|
||||
<html>
|
||||
<head>
|
||||
<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
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||||
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
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<title>Acknowledgments</title>
|
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<link rel="stylesheet" href="../boostbook.css" type="text/css">
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<meta name="generator" content="DocBook XSL Stylesheets V1.77.1">
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<link rel="home" href="../index.html" title="Chapter 1. Boost.Optional">
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<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
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<table cellpadding="2" width="100%"><tr>
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<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../boost.png"></td>
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<td align="center"><a href="../../../../../index.html">Home</a></td>
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<td align="center"><a href="../../../../../libs/libraries.htm">Libraries</a></td>
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<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td>
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<td align="center"><a href="../../../../../more/index.htm">More</a></td>
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<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>
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</div>
|
||||
<div class="section boost_optional_acknowledgments">
|
||||
<div class="section" title="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>
|
||||
<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
|
||||
<a name="boost_optional.acknowledgments.pre_formal_review"></a><h4>
|
||||
<a name="id583998"></a>
|
||||
<a class="link" href="acknowledgments.html#boost_optional.acknowledgments.pre_formal_review">Pre-formal
|
||||
review</a>
|
||||
</h4>
|
||||
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
|
||||
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
|
||||
<li class="listitem">
|
||||
Peter Dimov suggested the name 'optional', and was the first to point out
|
||||
the need for aligned storage.
|
||||
</li>
|
||||
<li class="listitem">
|
||||
Douglas Gregor developed 'type_with_alignment', and later Eric Friedman
|
||||
coded 'aligned_storage', which are the core of the optional class implementation.
|
||||
Douglas Gregor developed 'type_with_alignment', and later Eric Friedman coded
|
||||
'aligned_storage', which are the core of the optional class implementation.
|
||||
</li>
|
||||
<li class="listitem">
|
||||
Andrei Alexandrescu and Brian Parker also worked with aligned storage techniques
|
||||
@ -48,12 +48,12 @@
|
||||
design.
|
||||
</li>
|
||||
<li class="listitem">
|
||||
Vesa Karvonen and Douglas Gregor made quite useful comparisons between
|
||||
optional, variant and any; and made other relevant comments.
|
||||
Vesa Karvonen and Douglas Gregor made quite useful comparisons between optional,
|
||||
variant and any; and made other relevant comments.
|
||||
</li>
|
||||
<li class="listitem">
|
||||
Douglas Gregor and Peter Dimov commented on comparisons and evaluation
|
||||
in boolean contexts.
|
||||
Douglas Gregor and Peter Dimov commented on comparisons and evaluation in
|
||||
boolean contexts.
|
||||
</li>
|
||||
<li class="listitem">
|
||||
Eric Friedman helped understand the issues involved with aligned storage,
|
||||
@ -64,23 +64,23 @@
|
||||
Henney, David Abrahams, and others I can't recall.
|
||||
</li>
|
||||
</ul></div>
|
||||
<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
|
||||
<a name="boost_optional.acknowledgments.post_formal_review"></a><h4>
|
||||
<a name="id584068"></a>
|
||||
<a class="link" href="acknowledgments.html#boost_optional.acknowledgments.post_formal_review">Post-formal
|
||||
review</a>
|
||||
</h4>
|
||||
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
|
||||
<div class="itemizedlist"><ul class="itemizedlist" 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
|
||||
fueled the discussion about the analogy optional<>/smart pointer
|
||||
and about relational operators.
|
||||
fueled the discussion about the analogy optional<>/smart pointer and
|
||||
about relational operators.
|
||||
</li>
|
||||
<li class="listitem">
|
||||
Peter Dimov, Joel de Guzman, David Abrahams, Tanton Gibbs and Ian Hanson
|
||||
focused on the relational semantics of optional (originally undefined);
|
||||
concluding with the fact that the pointer-like interface doesn't make it
|
||||
a pointer so it shall have deep relational operators.
|
||||
focused on the relational semantics of optional (originally undefined); concluding
|
||||
with the fact that the pointer-like interface doesn't make it a pointer so
|
||||
it shall have deep relational operators.
|
||||
</li>
|
||||
<li class="listitem">
|
||||
Augustus Saunders also explored the different relational semantics between
|
||||
@ -96,22 +96,22 @@
|
||||
the Maybe type constructor (analogy originally pointed out by David Sankel).
|
||||
</li>
|
||||
<li class="listitem">
|
||||
Other comments were posted by Vincent Finn, Anthony Williams, Ed Brey,
|
||||
Rob Stewart, and others.
|
||||
Other comments were posted by Vincent Finn, Anthony Williams, Ed Brey, Rob
|
||||
Stewart, and others.
|
||||
</li>
|
||||
<li class="listitem">
|
||||
Joel de Guzman made the case for the support of references and helped with
|
||||
the proper semantics.
|
||||
</li>
|
||||
<li class="listitem">
|
||||
Mat Marcus shown the virtues of a value-oriented interface, influencing
|
||||
the current design, and contributed the idea of "none".
|
||||
Mat Marcus shown the virtues of a value-oriented interface, influencing the
|
||||
current design, and contributed the idea of "none".
|
||||
</li>
|
||||
</ul></div>
|
||||
</div>
|
||||
<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
|
||||
<td align="left"></td>
|
||||
<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<p>
|
||||
<td align="right"><div class="copyright-footer">Copyright <EFBFBD> 2003 -2007 Fernando Luis Cacciola Carballal<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>
|
||||
@ -119,7 +119,7 @@
|
||||
</tr></table>
|
||||
<hr>
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<div class="spirit-nav">
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<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>
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@ -1,11 +1,11 @@
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<a accesskey="p" href="implementation_notes.html"><img src="../../../../../doc/html/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.html"><img src="../../../../../doc/html/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../../../doc/html/images/home.png" alt="Home"></a><a accesskey="n" href="acknowledgments.html"><img src="../../../../../doc/html/images/next.png" alt="Next"></a>
|
||||
</div>
|
||||
<div class="section boost_optional_dependencies_and_portability">
|
||||
<div class="section" title="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>
|
||||
@ -34,7 +34,7 @@
|
||||
</div>
|
||||
<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
|
||||
<td align="left"></td>
|
||||
<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<p>
|
||||
<td align="right"><div class="copyright-footer">Copyright <EFBFBD> 2003 -2007 Fernando Luis Cacciola Carballal<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>
|
||||
@ -42,7 +42,7 @@
|
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</tr></table>
|
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|
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<div class="section boost_optional_development">
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<div class="section" title="Development">
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<div class="titlepage"><div><div><h2 class="title" style="clear: both">
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<a name="boost_optional.development"></a><a class="link" href="development.html" title="Development">Development</a>
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</h2></div></div></div>
|
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@ -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 boost_optional_development_the_models">
|
||||
<div class="section" title="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>
|
||||
@ -96,7 +96,7 @@
|
||||
value of <code class="computeroutput"><span class="identifier">T</span></code> or nothing.
|
||||
</p>
|
||||
<p>
|
||||
As of this writing I don't know of any precedent for a variable-size fixed-capacity
|
||||
As of this writing I don't know of any precedence for a variable-size fixed-capacity
|
||||
(of 1) stack-based container model for optional values, yet I believe this
|
||||
is the consequence of the lack of practical implementations of such a container
|
||||
rather than an inherent shortcoming of the container model.
|
||||
@ -110,7 +110,7 @@
|
||||
<p>
|
||||
Discriminated-union:
|
||||
</p>
|
||||
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
|
||||
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
|
||||
<li class="listitem">
|
||||
<span class="bold"><strong>deep-copy</strong></span> semantics: copies of the variant
|
||||
implies copies of the value.
|
||||
@ -132,8 +132,8 @@
|
||||
models testing if the optional is initialized
|
||||
</li>
|
||||
<li class="listitem">
|
||||
Trying to extract a <code class="computeroutput"><span class="identifier">T</span></code>
|
||||
from a variant when its current type is not <code class="computeroutput"><span class="identifier">T</span></code>,
|
||||
Trying to extract a <code class="computeroutput"><span class="identifier">T</span></code> from
|
||||
a variant when its current type is not <code class="computeroutput"><span class="identifier">T</span></code>,
|
||||
models the undefined behavior of trying to access the value of an uninitialized
|
||||
optional
|
||||
</li>
|
||||
@ -141,7 +141,7 @@
|
||||
<p>
|
||||
Single-element container:
|
||||
</p>
|
||||
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
|
||||
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
|
||||
<li class="listitem">
|
||||
<span class="bold"><strong>deep-copy</strong></span> semantics: copies of the container
|
||||
implies copies of the value.
|
||||
@ -162,13 +162,13 @@
|
||||
Testing if the container is empty models testing if the optional is initialized
|
||||
</li>
|
||||
<li class="listitem">
|
||||
Trying to extract a <code class="computeroutput"><span class="identifier">T</span></code>
|
||||
from an empty container models the undefined behavior of trying to access
|
||||
the value of an uninitialized optional
|
||||
Trying to extract a <code class="computeroutput"><span class="identifier">T</span></code> from
|
||||
an empty container models the undefined behavior of trying to access the
|
||||
value of an uninitialized optional
|
||||
</li>
|
||||
</ul></div>
|
||||
</div>
|
||||
<div class="section boost_optional_development_the_semantics">
|
||||
<div class="section" title="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>
|
||||
@ -193,19 +193,19 @@
|
||||
We can draw from the purpose of <code class="computeroutput"><span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">></span></code>
|
||||
the required basic semantics:
|
||||
</p>
|
||||
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
|
||||
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
|
||||
<li class="listitem">
|
||||
<span class="bold"><strong>Default Construction:</strong></span> To introduce a
|
||||
formally uninitialized wrapped object.
|
||||
<span class="bold"><strong>Default Construction:</strong></span> To introduce a formally
|
||||
uninitialized wrapped object.
|
||||
</li>
|
||||
<li class="listitem">
|
||||
<span class="bold"><strong>Direct Value Construction via copy:</strong></span>
|
||||
To introduce a formally initialized wrapped object whose value is obtained
|
||||
<span class="bold"><strong>Direct Value Construction via copy:</strong></span> To
|
||||
introduce a formally initialized wrapped object whose value is obtained
|
||||
as a copy of some object.
|
||||
</li>
|
||||
<li class="listitem">
|
||||
<span class="bold"><strong>Deep Copy Construction:</strong></span> To obtain a
|
||||
new yet equivalent wrapped object.
|
||||
<span class="bold"><strong>Deep Copy Construction:</strong></span> To obtain a new
|
||||
yet equivalent wrapped object.
|
||||
</li>
|
||||
<li class="listitem">
|
||||
<span class="bold"><strong>Direct Value Assignment (upon initialized):</strong></span>
|
||||
@ -221,8 +221,8 @@
|
||||
to the wrapped object the value of another wrapped object.
|
||||
</li>
|
||||
<li class="listitem">
|
||||
<span class="bold"><strong>Assignment (upon uninitialized):</strong></span> To
|
||||
initialize the wrapped object with value of another wrapped object.
|
||||
<span class="bold"><strong>Assignment (upon uninitialized):</strong></span> To initialize
|
||||
the wrapped object with value of another wrapped object.
|
||||
</li>
|
||||
<li class="listitem">
|
||||
<span class="bold"><strong>Deep Relational Operations (when supported by the
|
||||
@ -230,8 +230,7 @@
|
||||
the presence of uninitialized states.
|
||||
</li>
|
||||
<li class="listitem">
|
||||
<span class="bold"><strong>Value access:</strong></span> To unwrap the wrapped
|
||||
object.
|
||||
<span class="bold"><strong>Value access:</strong></span> To unwrap the wrapped object.
|
||||
</li>
|
||||
<li class="listitem">
|
||||
<span class="bold"><strong>Initialization state query:</strong></span> To determine
|
||||
@ -253,7 +252,7 @@
|
||||
via a pointer to the wrapped object or null.
|
||||
</p>
|
||||
</div>
|
||||
<div class="section boost_optional_development_the_interface">
|
||||
<div class="section" title="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 +291,9 @@
|
||||
operations not provided by <code class="computeroutput"><span class="identifier">T</span></code>
|
||||
itself which are supported by a special interface.
|
||||
</p>
|
||||
<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
|
||||
<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="id555569"></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
|
||||
Value Access in the presence of possibly untitialized optional objects: The
|
||||
operators * and -></a>
|
||||
</h5>
|
||||
@ -302,7 +301,7 @@
|
||||
A relevant feature of a pointer is that it can have a <span class="bold"><strong>null
|
||||
pointer value</strong></span>. This is a <span class="emphasis"><em>special</em></span> value which
|
||||
is used to indicate that the pointer is not referring to any object at all.
|
||||
In other words, null pointer values convey the notion of nonexistent objects.
|
||||
In other words, null pointer values convey the notion of inexistent objects.
|
||||
</p>
|
||||
<p>
|
||||
This meaning of the null pointer value allowed pointers to became a <span class="emphasis"><em>de
|
||||
@ -310,7 +309,7 @@
|
||||
to do to refer to a value which you don't really have is to use a null pointer
|
||||
value of the appropriate type. Pointers have been used for decades—from
|
||||
the days of C APIs to modern C++ libraries—to <span class="emphasis"><em>refer</em></span>
|
||||
to optional (that is, possibly nonexistent) objects; particularly as optional
|
||||
to optional (that is, possibly inexistent) objects; particularly as optional
|
||||
arguments to a function, but also quite often as optional data members.
|
||||
</p>
|
||||
<p>
|
||||
@ -357,9 +356,9 @@
|
||||
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>
|
||||
<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<T>
|
||||
<a name="boost_optional.development.the_interface.optional_lt_t_gt__as_a_model_of_optionalpointee"></a><h5>
|
||||
<a name="id555831"></a>
|
||||
<a class="link" href="development.html#boost_optional.development.the_interface.optional_lt_t_gt__as_a_model_of_optionalpointee">Optional<T>
|
||||
as a model of OptionalPointee</a>
|
||||
</h5>
|
||||
<p>
|
||||
@ -368,9 +367,9 @@
|
||||
about the possibly uninitialized state appealing to the familiar pointer
|
||||
semantics w.r.t. to null pointers.
|
||||
</p>
|
||||
<div class="warning"><table border="0" summary="Warning">
|
||||
<div class="warning" title="Warning"><table border="0" summary="Warning">
|
||||
<tr>
|
||||
<td rowspan="2" align="center" valign="top" width="25"><img alt="[Warning]" src="../../../../../doc/src/images/warning.png"></td>
|
||||
<td rowspan="2" align="center" valign="top" width="25"><img alt="[Warning]" src="../../../../../doc/html/images/warning.png"></td>
|
||||
<th align="left">Warning</th>
|
||||
</tr>
|
||||
<tr><td align="left" valign="top"><p>
|
||||
@ -399,7 +398,7 @@
|
||||
</div>
|
||||
<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
|
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<td align="left"></td>
|
||||
<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<p>
|
||||
<td align="right"><div class="copyright-footer">Copyright <EFBFBD> 2003 -2007 Fernando Luis Cacciola Carballal<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>
|
||||
@ -407,7 +406,7 @@
|
||||
</tr></table>
|
||||
<hr>
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<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>
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<div class="section boost_optional_examples">
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<div class="section" title="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 boost_optional_examples_optional_return_values">
|
||||
<div class="section" title="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"><</span><span class="keyword">char</span><span class="special">>(</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"><</span><span class="keyword">char</span><span class="special">>();</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"><</span><span class="keyword">char</span><span class="special">>();</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"><</span><span class="keyword">char</span><span class="special">></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">&&</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">&&</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 boost_optional_examples_optional_local_variables">
|
||||
<div class="section" title="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"><</span><span class="identifier">string</span><span class="special">></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">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="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="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">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="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="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 boost_optional_examples_optional_data_members">
|
||||
<div class="section" title="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">&</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">rect</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">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="keyword">void</span> <span class="identifier">draw</span> <span class="special">(</span> <span class="identifier">canvas</span><span class="special">&</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 boost_optional_examples_bypassing_expensive_unnecessary_default_construction">
|
||||
<div class="section" title="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>
|
||||
@ -133,7 +133,7 @@
|
||||
</div>
|
||||
<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
|
||||
<td align="left"></td>
|
||||
<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<p>
|
||||
<td align="right"><div class="copyright-footer">Copyright <EFBFBD> 2003 -2007 Fernando Luis Cacciola Carballal<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>
|
||||
@ -141,7 +141,7 @@
|
||||
</tr></table>
|
||||
<hr>
|
||||
<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>
|
||||
<a accesskey="p" href="detailed_semantics.html"><img src="../../../../../doc/html/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.html"><img src="../../../../../doc/html/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../../../doc/html/images/home.png" alt="Home"></a><a accesskey="n" href="optional_references.html"><img src="../../../../../doc/html/images/next.png" alt="Next"></a>
|
||||
</div>
|
||||
</body>
|
||||
</html>
|
||||
|
||||
@ -1,11 +1,11 @@
|
||||
<html>
|
||||
<head>
|
||||
<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
|
||||
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
|
||||
<title>Exception Safety Guarantees</title>
|
||||
<link rel="stylesheet" href="../boostbook.css" type="text/css">
|
||||
<meta name="generator" content="DocBook XSL Stylesheets V1.77.1">
|
||||
<link rel="home" href="../index.html" title="Chapter 1. Boost.Optional">
|
||||
<link rel="up" href="../index.html" title="Chapter 1. Boost.Optional">
|
||||
<meta name="generator" content="DocBook XSL Stylesheets V1.75.2">
|
||||
<link rel="home" href="../index.html" title="Chapter<EFBFBD>1.<2E>Boost.Optional">
|
||||
<link rel="up" href="../index.html" title="Chapter<EFBFBD>1.<2E>Boost.Optional">
|
||||
<link rel="prev" href="a_note_about_optional_bool_.html" title="A note about optional<bool>">
|
||||
<link rel="next" href="type_requirements.html" title="Type requirements">
|
||||
</head>
|
||||
@ -13,16 +13,16 @@
|
||||
<table cellpadding="2" width="100%"><tr>
|
||||
<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../boost.png"></td>
|
||||
<td align="center"><a href="../../../../../index.html">Home</a></td>
|
||||
<td align="center"><a href="../../../../../libs/libraries.htm">Libraries</a></td>
|
||||
<td align="center"><a href="../../../../libraries.htm">Libraries</a></td>
|
||||
<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td>
|
||||
<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td>
|
||||
<td align="center"><a href="../../../../../more/index.htm">More</a></td>
|
||||
</tr></table>
|
||||
<hr>
|
||||
<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>
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||||
<a accesskey="p" href="a_note_about_optional_bool_.html"><img src="../../../../../doc/html/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.html"><img src="../../../../../doc/html/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../../../doc/html/images/home.png" alt="Home"></a><a accesskey="n" href="type_requirements.html"><img src="../../../../../doc/html/images/next.png" alt="Next"></a>
|
||||
</div>
|
||||
<div class="section boost_optional_exception_safety_guarantees">
|
||||
<div class="section" title="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>
|
||||
@ -31,29 +31,21 @@
|
||||
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" style="list-style-type: disc; ">
|
||||
<li class="listitem">
|
||||
<code class="computeroutput"><span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">>::</span><span class="keyword">operator</span><span class="special">=</span> <span class="special">(</span> <span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">></span> <span class="keyword">const</span><span class="special">&</span> <span class="special">)</span></code>
|
||||
</li>
|
||||
<li class="listitem">
|
||||
<code class="computeroutput"><span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">>::</span><span class="keyword">operator</span><span class="special">=</span> <span class="special">(</span> <span class="identifier">T</span> <span class="keyword">const</span><span class="special">&</span> <span class="special">)</span></code>
|
||||
</li>
|
||||
<li class="listitem">
|
||||
<code class="computeroutput"><span class="keyword">template</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">U</span><span class="special">></span> <span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">>::</span><span class="keyword">operator</span><span class="special">=</span> <span class="special">(</span> <span class="identifier">optional</span><span class="special"><</span><span class="identifier">U</span><span class="special">></span> <span class="keyword">const</span><span class="special">&</span> <span class="special">)</span></code>
|
||||
</li>
|
||||
<li class="listitem">
|
||||
<code class="computeroutput"><span class="keyword">template</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">InPlaceFactory</span><span class="special">></span> <span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">>::</span><span class="keyword">operator</span><span class="special">=</span> <span class="special">(</span> <span class="identifier">InPlaceFactory</span>
|
||||
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
|
||||
<li class="listitem"><code class="computeroutput"><span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">>::</span><span class="keyword">operator</span><span class="special">=</span> <span class="special">(</span> <span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">></span>
|
||||
<span class="keyword">const</span><span class="special">&</span>
|
||||
<span class="special">)</span></code>
|
||||
</li>
|
||||
<li class="listitem">
|
||||
<code class="computeroutput"><span class="keyword">template</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">TypedInPlaceFactory</span><span class="special">></span> <span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">>::</span><span class="keyword">operator</span><span class="special">=</span> <span class="special">(</span> <span class="identifier">TypedInPlaceFactory</span>
|
||||
<span class="special">)</span></code></li>
|
||||
<li class="listitem"><code class="computeroutput"><span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">>::</span><span class="keyword">operator</span><span class="special">=</span> <span class="special">(</span> <span class="identifier">T</span> <span class="keyword">const</span><span class="special">&</span> <span class="special">)</span></code></li>
|
||||
<li class="listitem"><code class="computeroutput"><span class="keyword">template</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">U</span><span class="special">></span> <span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">>::</span><span class="keyword">operator</span><span class="special">=</span> <span class="special">(</span> <span class="identifier">optional</span><span class="special"><</span><span class="identifier">U</span><span class="special">></span>
|
||||
<span class="keyword">const</span><span class="special">&</span>
|
||||
<span class="special">)</span> </code>
|
||||
</li>
|
||||
<li class="listitem">
|
||||
<code class="computeroutput"><span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">>::</span><span class="identifier">reset</span> <span class="special">(</span> <span class="identifier">T</span> <span class="keyword">const</span><span class="special">&)</span></code>
|
||||
</li>
|
||||
<span class="special">)</span></code></li>
|
||||
<li class="listitem"><code class="computeroutput"><span class="keyword">template</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">InPlaceFactory</span><span class="special">></span> <span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">>::</span><span class="keyword">operator</span><span class="special">=</span> <span class="special">(</span> <span class="identifier">InPlaceFactory</span>
|
||||
<span class="keyword">const</span><span class="special">&</span>
|
||||
<span class="special">)</span></code></li>
|
||||
<li class="listitem"><code class="computeroutput"><span class="keyword">template</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">TypedInPlaceFactory</span><span class="special">></span> <span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">>::</span><span class="keyword">operator</span><span class="special">=</span> <span class="special">(</span> <span class="identifier">TypedInPlaceFactory</span>
|
||||
<span class="keyword">const</span><span class="special">&</span>
|
||||
<span class="special">)</span> </code></li>
|
||||
<li class="listitem"><code class="computeroutput"><span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">>:::</span><span class="identifier">reset</span> <span class="special">(</span> <span class="identifier">T</span> <span class="keyword">const</span><span class="special">&)</span></code></li>
|
||||
</ul></div>
|
||||
<p>
|
||||
Can only <span class="emphasis"><em>guarantee</em></span> the <span class="underline">basic
|
||||
@ -64,13 +56,9 @@
|
||||
<p>
|
||||
On the other hand, the <span class="emphasis"><em>uninitializing</em></span> methods:
|
||||
</p>
|
||||
<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"><</span><span class="identifier">T</span><span class="special">>::</span><span class="keyword">operator</span><span class="special">=</span> <span class="special">(</span> <span class="identifier">detail</span><span class="special">::</span><span class="identifier">none_t</span> <span class="special">)</span></code>
|
||||
</li>
|
||||
<li class="listitem">
|
||||
<code class="computeroutput"><span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">>::</span><span class="identifier">reset</span><span class="special">()</span></code>
|
||||
</li>
|
||||
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
|
||||
<li class="listitem"><code class="computeroutput"><span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">>::</span><span class="keyword">operator</span><span class="special">=</span> <span class="special">(</span> <span class="identifier">detail</span><span class="special">::</span><span class="identifier">none_t</span> <span class="special">)</span></code></li>
|
||||
<li class="listitem"><code class="computeroutput"><span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">>::</span><span class="identifier">reset</span><span class="special">()</span></code></li>
|
||||
</ul></div>
|
||||
<p>
|
||||
Provide the no-throw guarantee (assuming a no-throw <code class="computeroutput"><span class="identifier">T</span><span class="special">::~</span><span class="identifier">T</span><span class="special">()</span></code>)
|
||||
@ -84,10 +72,10 @@
|
||||
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"><</span><span class="identifier">T</span><span class="special">></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 +83,37 @@
|
||||
<span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">></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"><</span><span class="identifier">T</span><span class="special">></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>
|
||||
<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>
|
||||
<a name="boost_optional.exception_safety_guarantees.swap"></a><h4>
|
||||
<a name="id583497"></a>
|
||||
<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"><</span><span class="identifier">T</span><span class="special">>&,</span>
|
||||
@ -138,7 +126,7 @@
|
||||
</div>
|
||||
<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
|
||||
<td align="left"></td>
|
||||
<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<p>
|
||||
<td align="right"><div class="copyright-footer">Copyright <EFBFBD> 2003 -2007 Fernando Luis Cacciola Carballal<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>
|
||||
@ -146,7 +134,7 @@
|
||||
</tr></table>
|
||||
<hr>
|
||||
<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>
|
||||
<a accesskey="p" href="a_note_about_optional_bool_.html"><img src="../../../../../doc/html/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.html"><img src="../../../../../doc/html/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../../../doc/html/images/home.png" alt="Home"></a><a accesskey="n" href="type_requirements.html"><img src="../../../../../doc/html/images/next.png" alt="Next"></a>
|
||||
</div>
|
||||
</body>
|
||||
</html>
|
||||
|
||||
@ -1,11 +1,11 @@
|
||||
<html>
|
||||
<head>
|
||||
<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
|
||||
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
|
||||
<title>Implementation Notes</title>
|
||||
<link rel="stylesheet" href="../boostbook.css" type="text/css">
|
||||
<meta name="generator" content="DocBook XSL Stylesheets V1.77.1">
|
||||
<link rel="home" href="../index.html" title="Chapter 1. Boost.Optional">
|
||||
<link rel="up" href="../index.html" title="Chapter 1. Boost.Optional">
|
||||
<meta name="generator" content="DocBook XSL Stylesheets V1.75.2">
|
||||
<link rel="home" href="../index.html" title="Chapter<EFBFBD>1.<2E>Boost.Optional">
|
||||
<link rel="up" href="../index.html" title="Chapter<EFBFBD>1.<2E>Boost.Optional">
|
||||
<link rel="prev" href="type_requirements.html" title="Type requirements">
|
||||
<link rel="next" href="dependencies_and_portability.html" title="Dependencies and Portability">
|
||||
</head>
|
||||
@ -13,16 +13,16 @@
|
||||
<table cellpadding="2" width="100%"><tr>
|
||||
<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../boost.png"></td>
|
||||
<td align="center"><a href="../../../../../index.html">Home</a></td>
|
||||
<td align="center"><a href="../../../../../libs/libraries.htm">Libraries</a></td>
|
||||
<td align="center"><a href="../../../../libraries.htm">Libraries</a></td>
|
||||
<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td>
|
||||
<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td>
|
||||
<td align="center"><a href="../../../../../more/index.htm">More</a></td>
|
||||
</tr></table>
|
||||
<hr>
|
||||
<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>
|
||||
<a accesskey="p" href="type_requirements.html"><img src="../../../../../doc/html/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.html"><img src="../../../../../doc/html/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../../../doc/html/images/home.png" alt="Home"></a><a accesskey="n" href="dependencies_and_portability.html"><img src="../../../../../doc/html/images/next.png" alt="Next"></a>
|
||||
</div>
|
||||
<div class="section boost_optional_implementation_notes">
|
||||
<div class="section" title="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>
|
||||
@ -41,7 +41,7 @@
|
||||
</div>
|
||||
<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
|
||||
<td align="left"></td>
|
||||
<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<p>
|
||||
<td align="right"><div class="copyright-footer">Copyright <EFBFBD> 2003 -2007 Fernando Luis Cacciola Carballal<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>
|
||||
@ -49,7 +49,7 @@
|
||||
</tr></table>
|
||||
<hr>
|
||||
<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>
|
||||
<a accesskey="p" href="type_requirements.html"><img src="../../../../../doc/html/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.html"><img src="../../../../../doc/html/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../../../doc/html/images/home.png" alt="Home"></a><a accesskey="n" href="dependencies_and_portability.html"><img src="../../../../../doc/html/images/next.png" alt="Next"></a>
|
||||
</div>
|
||||
</body>
|
||||
</html>
|
||||
|
||||
@ -1,11 +1,11 @@
|
||||
<html>
|
||||
<head>
|
||||
<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
|
||||
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
|
||||
<title>In-Place Factories</title>
|
||||
<link rel="stylesheet" href="../boostbook.css" type="text/css">
|
||||
<meta name="generator" content="DocBook XSL Stylesheets V1.77.1">
|
||||
<link rel="home" href="../index.html" title="Chapter 1. Boost.Optional">
|
||||
<link rel="up" href="../index.html" title="Chapter 1. Boost.Optional">
|
||||
<meta name="generator" content="DocBook XSL Stylesheets V1.75.2">
|
||||
<link rel="home" href="../index.html" title="Chapter<EFBFBD>1.<2E>Boost.Optional">
|
||||
<link rel="up" href="../index.html" title="Chapter<EFBFBD>1.<2E>Boost.Optional">
|
||||
<link rel="prev" href="rebinding_semantics_for_assignment_of_optional_references.html" title="Rebinding semantics for assignment of optional references">
|
||||
<link rel="next" href="a_note_about_optional_bool_.html" title="A note about optional<bool>">
|
||||
</head>
|
||||
@ -13,16 +13,16 @@
|
||||
<table cellpadding="2" width="100%"><tr>
|
||||
<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../boost.png"></td>
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||||
<td align="center"><a href="../../../../../index.html">Home</a></td>
|
||||
<td align="center"><a href="../../../../../libs/libraries.htm">Libraries</a></td>
|
||||
<td align="center"><a href="../../../../libraries.htm">Libraries</a></td>
|
||||
<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td>
|
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<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td>
|
||||
<td align="center"><a href="../../../../../more/index.htm">More</a></td>
|
||||
</tr></table>
|
||||
<hr>
|
||||
<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>
|
||||
<a accesskey="p" href="rebinding_semantics_for_assignment_of_optional_references.html"><img src="../../../../../doc/html/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.html"><img src="../../../../../doc/html/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../../../doc/html/images/home.png" alt="Home"></a><a accesskey="n" href="a_note_about_optional_bool_.html"><img src="../../../../../doc/html/images/next.png" alt="Next"></a>
|
||||
</div>
|
||||
<div class="section boost_optional_in_place_factories">
|
||||
<div class="section" title="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"><</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="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"><</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="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" style="list-style-type: disc; ">
|
||||
<div class="itemizedlist"><ul class="itemizedlist" 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>
|
||||
@ -182,7 +182,7 @@
|
||||
</div>
|
||||
<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
|
||||
<td align="left"></td>
|
||||
<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<p>
|
||||
<td align="right"><div class="copyright-footer">Copyright <EFBFBD> 2003 -2007 Fernando Luis Cacciola Carballal<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>
|
||||
@ -190,7 +190,7 @@
|
||||
</tr></table>
|
||||
<hr>
|
||||
<div class="spirit-nav">
|
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<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>
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@ -1,11 +1,11 @@
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|
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<title>Optional references</title>
|
||||
<link rel="stylesheet" href="../boostbook.css" type="text/css">
|
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<meta name="generator" content="DocBook XSL Stylesheets V1.77.1">
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<link rel="home" href="../index.html" title="Chapter 1. Boost.Optional">
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<meta name="generator" content="DocBook XSL Stylesheets V1.75.2">
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<link rel="up" href="../index.html" title="Chapter<EFBFBD>1.<2E>Boost.Optional">
|
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<link rel="prev" href="examples.html" title="Examples">
|
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|
||||
</head>
|
||||
@ -13,16 +13,16 @@
|
||||
<table cellpadding="2" width="100%"><tr>
|
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<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../boost.png"></td>
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<td align="center"><a href="../../../../../index.html">Home</a></td>
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<a accesskey="p" href="examples.html"><img src="../../../../../doc/html/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.html"><img src="../../../../../doc/html/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../../../doc/html/images/home.png" alt="Home"></a><a accesskey="n" href="rebinding_semantics_for_assignment_of_optional_references.html"><img src="../../../../../doc/html/images/next.png" alt="Next"></a>
|
||||
</div>
|
||||
<div class="section boost_optional_optional_references">
|
||||
<div class="section" title="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" style="list-style-type: disc; ">
|
||||
<div class="itemizedlist"><ul class="itemizedlist" 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" style="list-style-type: disc; ">
|
||||
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
|
||||
<li class="listitem">
|
||||
Copies of <code class="computeroutput"><span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">&></span></code>
|
||||
will copy the references but all these references will nonetheless reefer
|
||||
@ -71,7 +71,7 @@
|
||||
</div>
|
||||
<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
|
||||
<td align="left"></td>
|
||||
<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<p>
|
||||
<td align="right"><div class="copyright-footer">Copyright <EFBFBD> 2003 -2007 Fernando Luis Cacciola Carballal<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>
|
||||
@ -79,7 +79,7 @@
|
||||
</tr></table>
|
||||
<hr>
|
||||
<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>
|
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<a accesskey="p" href="examples.html"><img src="../../../../../doc/html/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.html"><img src="../../../../../doc/html/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../../../doc/html/images/home.png" alt="Home"></a><a accesskey="n" href="rebinding_semantics_for_assignment_of_optional_references.html"><img src="../../../../../doc/html/images/next.png" alt="Next"></a>
|
||||
</div>
|
||||
</body>
|
||||
</html>
|
||||
|
||||
@ -1,11 +1,11 @@
|
||||
<html>
|
||||
<head>
|
||||
<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
|
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<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
|
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<title>Rebinding semantics for assignment of optional references</title>
|
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<link rel="stylesheet" href="../boostbook.css" type="text/css">
|
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<meta name="generator" content="DocBook XSL Stylesheets V1.77.1">
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<link rel="home" href="../index.html" title="Chapter 1. Boost.Optional">
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|
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<link rel="prev" href="optional_references.html" title="Optional references">
|
||||
<link rel="next" href="in_place_factories.html" title="In-Place Factories">
|
||||
</head>
|
||||
@ -13,16 +13,16 @@
|
||||
<table cellpadding="2" width="100%"><tr>
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<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../boost.png"></td>
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<td align="center"><a href="../../../../../index.html">Home</a></td>
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<td align="center"><a href="../../../../libraries.htm">Libraries</a></td>
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<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td>
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<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>
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<a accesskey="p" href="optional_references.html"><img src="../../../../../doc/html/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.html"><img src="../../../../../doc/html/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../../../doc/html/images/home.png" alt="Home"></a><a accesskey="n" href="in_place_factories.html"><img src="../../../../../doc/html/images/next.png" alt="Next"></a>
|
||||
</div>
|
||||
<div class="section boost_optional_rebinding_semantics_for_assignment_of_optional_references">
|
||||
<div class="section" title="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>
|
||||
@ -36,23 +36,23 @@
|
||||
<span class="keyword">int</span><span class="special">&</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"><</span><span class="keyword">int</span><span class="special">&></span> <span class="identifier">ora</span> <span class="special">;</span>
|
||||
<span class="identifier">optional</span><span class="special"><</span><span class="keyword">int</span><span class="special">&></span> <span class="identifier">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
|
||||
object; its value changes but the reference is never rebound.
|
||||
object; it's value changes but the reference is never rebound.
|
||||
</p>
|
||||
<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="special">&</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">&</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"><</span><span class="identifier">T</span><span class="special">&></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">&</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"><</span><span class="keyword">int</span><span class="special">&></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"><</span><span class="keyword">int</span><span class="special">&></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">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>
|
||||
<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>
|
||||
<a name="boost_optional.rebinding_semantics_for_assignment_of_optional_references.rationale"></a><h4>
|
||||
<a name="id579234"></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>
|
||||
<p>
|
||||
Rebinding semantics for the assignment of <span class="emphasis"><em>initialized </em></span>
|
||||
@ -117,16 +117,16 @@
|
||||
or not.
|
||||
</p>
|
||||
<p>
|
||||
That is, you would have to discriminate in order to be consistent.
|
||||
That is, you would have to discriminate in order to be consistency.
|
||||
</p>
|
||||
<p>
|
||||
If in your code rebinding to another object is not an option, then it is very
|
||||
likely that binding for the first time isn't either. In such case, assignment
|
||||
If in your code rebinding to another object is not an option, then is very
|
||||
likely that binding for the fist time isn't either. In such case, assignment
|
||||
to an <span class="emphasis"><em>uninitialized </em></span> <code class="computeroutput"><span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">&></span></code>
|
||||
shall be prohibited. It is quite possible that in such a scenario it is a precondition
|
||||
that the lvalue must be already initialized. If it isn't, then binding for
|
||||
the first time is OK while rebinding is not which is IMO very unlikely. In
|
||||
such a scenario, you can assign the value itself directly, as in:
|
||||
shall be prohibited. It is quite possible that in such scenario the precondition
|
||||
that the lvalue must be already initialized exist. If it doesn't, then binding
|
||||
for the first time is OK while rebinding is not which is IMO very unlikely.
|
||||
In such scenario, you can assign the value itself directly, as in:
|
||||
</p>
|
||||
<pre class="programlisting"><span class="identifier">assert</span><span class="special">(!!</span><span class="identifier">opt</span><span class="special">);</span>
|
||||
<span class="special">*</span><span class="identifier">opt</span><span class="special">=</span><span class="identifier">value</span><span class="special">;</span>
|
||||
@ -134,7 +134,7 @@
|
||||
</div>
|
||||
<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
|
||||
<td align="left"></td>
|
||||
<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<p>
|
||||
<td align="right"><div class="copyright-footer">Copyright <EFBFBD> 2003 -2007 Fernando Luis Cacciola Carballal<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>
|
||||
@ -142,7 +142,7 @@
|
||||
</tr></table>
|
||||
<hr>
|
||||
<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>
|
||||
<a accesskey="p" href="optional_references.html"><img src="../../../../../doc/html/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.html"><img src="../../../../../doc/html/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../../../doc/html/images/home.png" alt="Home"></a><a accesskey="n" href="in_place_factories.html"><img src="../../../../../doc/html/images/next.png" alt="Next"></a>
|
||||
</div>
|
||||
</body>
|
||||
</html>
|
||||
|
||||
@ -1,11 +1,11 @@
|
||||
<html>
|
||||
<head>
|
||||
<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
|
||||
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
|
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<title>Synopsis</title>
|
||||
<link rel="stylesheet" href="../boostbook.css" type="text/css">
|
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<meta name="generator" content="DocBook XSL Stylesheets V1.77.1">
|
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<link rel="home" href="../index.html" title="Chapter 1. Boost.Optional">
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<link rel="up" href="../index.html" title="Chapter 1. Boost.Optional">
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<meta name="generator" content="DocBook XSL Stylesheets V1.75.2">
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<link rel="home" href="../index.html" title="Chapter<EFBFBD>1.<2E>Boost.Optional">
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<link rel="up" href="../index.html" title="Chapter<EFBFBD>1.<2E>Boost.Optional">
|
||||
<link rel="prev" href="development.html" title="Development">
|
||||
<link rel="next" href="detailed_semantics.html" title="Detailed Semantics">
|
||||
</head>
|
||||
@ -13,38 +13,36 @@
|
||||
<table cellpadding="2" width="100%"><tr>
|
||||
<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../boost.png"></td>
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||||
<td align="center"><a href="../../../../../index.html">Home</a></td>
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<td align="center"><a href="../../../../../libs/libraries.htm">Libraries</a></td>
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<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td>
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<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td>
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<td align="center"><a href="../../../../../more/index.htm">More</a></td>
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||||
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||||
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<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>
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</div>
|
||||
<div class="section boost_optional_synopsis">
|
||||
<div class="section" title="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>
|
||||
<pre class="programlisting"><code class="computeroutput"><span class="comment">// In Header: <</span></code><a href="../../../../../boost/optional/optional.hpp" target="_top">boost/optional/optional.hpp</a><span class="comment">></span>
|
||||
|
||||
<span class="keyword">namespace</span> <span class="identifier">boost</span> <span class="special">{</span>
|
||||
<pre class="programlisting"><span class="keyword">namespace</span> <span class="identifier">boost</span> <span class="special">{</span>
|
||||
|
||||
<span class="keyword">template</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">></span>
|
||||
<span class="keyword">class</span> <span class="identifier">optional</span>
|
||||
<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">&</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">&</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">&</span> <span class="identifier">v</span> <span class="special">)</span> <span class="special">;</span> <a class="link" href="detailed_semantics.html#reference_optional_constructor_bool_value"><span class="inlinemediaobject"><img src="../images/callouts/R.png" alt="R"></span></a>
|
||||
|
||||
<span class="identifier">optional</span> <span class="special">(</span> <span class="identifier">optional</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">rhs</span> <span class="special">)</span> <span class="special">;</span> <a class="link" href="detailed_semantics.html#reference_optional_constructor_optional"><span class="inlinemediaobject"><img src="../images/callouts/R.png" alt="R"></span></a>
|
||||
|
||||
@ -62,15 +60,15 @@
|
||||
|
||||
<span class="keyword">template</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">U</span><span class="special">></span> <span class="identifier">optional</span><span class="special">&</span> <span class="keyword">operator</span> <span class="special">=</span> <span class="special">(</span> <span class="identifier">optional</span><span class="special"><</span><span class="identifier">U</span><span class="special">></span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">rhs</span> <span class="special">)</span> <span class="special">;</span> <a class="link" href="detailed_semantics.html#reference_optional_operator_equal_other_optional"><span class="inlinemediaobject"><img src="../images/callouts/R.png" alt="R"></span></a>
|
||||
|
||||
<span class="keyword">template</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">InPlaceFactory</span><span class="special">></span> <span class="identifier">optional</span><span class="special">&</span> <span class="keyword">operator</span> <span class="special">=</span> <span class="special">(</span> <span class="identifier">InPlaceFactory</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">f</span> <span class="special">)</span> <span class="special">;</span> <a class="link" href="detailed_semantics.html#reference_optional_operator_equal_factory"><span class="inlinemediaobject"><img src="../images/callouts/R.png" alt="R"></span></a>
|
||||
<span class="keyword">template</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">InPlaceFactory</span><span class="special">></span> <span class="identifier">optional</span><span class="special">&</span> <span class="keyword">operator</span> <span class="special">=</span> <span class="special">(</span> <span class="identifier">InPlaceFactory</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">f</span> <span class="special">)</span> <span class="special">;</span>
|
||||
|
||||
<span class="keyword">template</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">TypedInPlaceFactory</span><span class="special">></span> <span class="identifier">optional</span><span class="special">&</span> <span class="keyword">operator</span> <span class="special">=</span> <span class="special">(</span> <span class="identifier">TypedInPlaceFactory</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">f</span> <span class="special">)</span> <span class="special">;</span> <a class="link" href="detailed_semantics.html#reference_optional_operator_equal_factory"><span class="inlinemediaobject"><img src="../images/callouts/R.png" alt="R"></span></a>
|
||||
<span class="keyword">template</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">TypedInPlaceFactory</span><span class="special">></span> <span class="identifier">optional</span><span class="special">&</span> <span class="keyword">operator</span> <span class="special">=</span> <span class="special">(</span> <span class="identifier">TypedInPlaceFactory</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">f</span> <span class="special">)</span> <span class="special">;</span>
|
||||
|
||||
<span class="identifier">T</span> <span class="keyword">const</span><span class="special">&</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">&</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">&</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">&</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">&</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">&</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">->()</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">->()</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 +83,16 @@
|
||||
|
||||
<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 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)</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">void</span> <span class="identifier">reset</span> <span class="special">(</span> <span class="identifier">T</span> <span class="keyword">const</span><span class="special">&</span> <span class="special">)</span> <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="identifier">T</span> <span class="keyword">const</span><span class="special">&</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="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 +108,14 @@
|
||||
|
||||
<span class="keyword">template</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">></span> <span class="keyword">inline</span> <span class="keyword">bool</span> <span class="keyword">operator</span> <span class="special">>=</span> <span class="special">(</span> <span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">></span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">x</span><span class="special">,</span> <span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">></span> <span class="keyword">const</span><span class="special">&</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"><</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">></span> <span class="keyword">inline</span> <span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">></span> <span class="identifier">make_optional</span> <span class="special">(</span> <span class="identifier">T</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">v</span> <span class="special">)</span> <span class="special">;</span> <a class="link" href="detailed_semantics.html#reference_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"><</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">></span> <span class="keyword">inline</span> <span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">></span> <span class="identifier">make_optional</span> <span class="special">(</span> <span class="identifier">T</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">v</span> <span class="special">)</span> <span class="special">;</span> <a class="link" href="detailed_semantics.html#reference_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"><</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">></span> <span class="keyword">inline</span> <span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">></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">&</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"><</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">></span> <span class="keyword">inline</span> <span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">></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">&</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"><</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">></span> <span class="keyword">inline</span> <span class="identifier">T</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">get_optional_value_or</span> <span class="special">(</span> <span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">></span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">opt</span><span class="special">,</span> <span class="identifier">T</span> <span class="keyword">const</span><span class="special">&</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"><</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">></span> <span class="keyword">inline</span> <span class="identifier">T</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">get_optional_value_or</span> <span class="special">(</span> <span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">></span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">opt</span><span class="special">,</span> <span class="identifier">T</span> <span class="keyword">const</span><span class="special">&</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"><</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">></span> <span class="keyword">inline</span> <span class="identifier">T</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">get</span> <span class="special">(</span> <span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">></span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">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>
|
||||
|
||||
@ -133,12 +131,12 @@
|
||||
|
||||
<span class="keyword">template</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">></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"><</span><span class="identifier">T</span><span class="special">>&</span> <span class="identifier">x</span><span class="special">,</span> <span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">>&</span> <span class="identifier">y</span> <span class="special">)</span> <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>
|
||||
<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
|
||||
<td align="left"></td>
|
||||
<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<p>
|
||||
<td align="right"><div class="copyright-footer">Copyright <EFBFBD> 2003 -2007 Fernando Luis Cacciola Carballal<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>
|
||||
@ -146,7 +144,7 @@
|
||||
</tr></table>
|
||||
<hr>
|
||||
<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>
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@ -1,11 +1,11 @@
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|
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<link rel="stylesheet" href="../boostbook.css" type="text/css">
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<link rel="next" href="implementation_notes.html" title="Implementation Notes">
|
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|
||||
@ -13,16 +13,16 @@
|
||||
<table cellpadding="2" width="100%"><tr>
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<a accesskey="p" href="exception_safety_guarantees.html"><img src="../../../../../doc/html/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.html"><img src="../../../../../doc/html/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../../../doc/html/images/home.png" alt="Home"></a><a accesskey="n" href="implementation_notes.html"><img src="../../../../../doc/html/images/next.png" alt="Next"></a>
|
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|
||||
<div class="section boost_optional_type_requirements">
|
||||
<div class="section" title="Type requirements">
|
||||
<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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</h2></div></div></div>
|
||||
@ -39,7 +39,7 @@
|
||||
</div>
|
||||
<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
|
||||
<td align="left"></td>
|
||||
<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<p>
|
||||
<td align="right"><div class="copyright-footer">Copyright <EFBFBD> 2003 -2007 Fernando Luis Cacciola Carballal<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>
|
||||
@ -47,7 +47,7 @@
|
||||
</tr></table>
|
||||
<hr>
|
||||
<div class="spirit-nav">
|
||||
<a accesskey="p" href="exception_safety_guarantees.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="implementation_notes.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a>
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<a accesskey="p" href="exception_safety_guarantees.html"><img src="../../../../../doc/html/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.html"><img src="../../../../../doc/html/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../../../doc/html/images/home.png" alt="Home"></a><a accesskey="n" href="implementation_notes.html"><img src="../../../../../doc/html/images/next.png" alt="Next"></a>
|
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|
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</body>
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||||
</html>
|
||||
|
||||
@ -1,33 +1,33 @@
|
||||
<html>
|
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<head>
|
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<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
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<link rel="stylesheet" href="boostbook.css" type="text/css">
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<meta name="generator" content="DocBook XSL Stylesheets V1.77.1">
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<link rel="next" href="boost_optional/development.html" title="Development">
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<div class="chapter" title="Chapter<65>1.<2E>Boost.Optional">
|
||||
<div class="titlepage"><div>
|
||||
<div><h2 class="title">
|
||||
<a name="optional"></a>Chapter 1. Boost.Optional</h2></div>
|
||||
<a name="optional"></a>Chapter<EFBFBD>1.<2E>Boost.Optional</h2></div>
|
||||
<div><div class="author"><h3 class="author">
|
||||
<span class="firstname">Fernando Luis</span> <span class="surname">Cacciola Carballal</span>
|
||||
</h3></div></div>
|
||||
<div><p class="copyright">Copyright © 2003-2007 Fernando Luis Cacciola Carballal</p></div>
|
||||
<div><div class="legalnotice">
|
||||
<a name="optional.legal"></a><p>
|
||||
<div><p class="copyright">Copyright <EFBFBD> 2003 -2007 Fernando Luis Cacciola Carballal</p></div>
|
||||
<div><div class="legalnotice" title="Legal Notice">
|
||||
<a name="id553943"></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 optional_motivation">
|
||||
<div class="section" title="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>
|
||||
@ -79,9 +79,10 @@
|
||||
Consider these functions which should return a value but which might not have
|
||||
a value to return:
|
||||
</p>
|
||||
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
|
||||
<div class="itemizedlist"><ul class="itemizedlist" 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>
|
||||
(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>
|
||||
<li class="listitem">
|
||||
(B) <code class="computeroutput"><span class="keyword">char</span> <span class="identifier">get_async_input</span><span class="special">();</span></code>
|
||||
@ -145,7 +146,7 @@
|
||||
<span class="identifier">std</span><span class="special">::</span><span class="identifier">pair</span><span class="special"><</span><span class="identifier">point</span><span class="special">,</span><span class="keyword">bool</span><span class="special">></span> <span class="identifier">polygon</span><span class="special">::</span><span class="identifier">get_any_point_effectively_inside</span><span class="special">();</span>
|
||||
</pre>
|
||||
<p>
|
||||
These functions use a consistent interface for dealing with possibly nonexistent
|
||||
These functions use a consistent interface for dealing with possibly inexistent
|
||||
results:
|
||||
</p>
|
||||
<pre class="programlisting"><span class="identifier">std</span><span class="special">::</span><span class="identifier">pair</span><span class="special"><</span><span class="identifier">point</span><span class="special">,</span><span class="keyword">bool</span><span class="special">></span> <span class="identifier">p</span> <span class="special">=</span> <span class="identifier">poly</span><span class="special">.</span><span class="identifier">get_any_point_effectively_inside</span><span class="special">();</span>
|
||||
@ -161,12 +162,14 @@
|
||||
Clearly, we need a better idiom.
|
||||
</p>
|
||||
</div>
|
||||
<p>
|
||||
</p>
|
||||
</div>
|
||||
<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
|
||||
<td align="left"><p><small>Last revised: February 16, 2013 at 19:42:23 GMT</small></p></td>
|
||||
<td align="left"><p><small>Last revised: November 20, 2009 at 10:24:28 GMT</small></p></td>
|
||||
<td align="right"><div class="copyright-footer"></div></td>
|
||||
</tr></table>
|
||||
<hr>
|
||||
<div class="spirit-nav"><a accesskey="n" href="boost_optional/development.html"><img src="../../../../doc/src/images/next.png" alt="Next"></a></div>
|
||||
<div class="spirit-nav"><a accesskey="n" href="boost_optional/development.html"><img src="../../../../doc/html/images/next.png" alt="Next"></a></div>
|
||||
</body>
|
||||
</html>
|
||||
|
||||
@ -99,7 +99,7 @@ functions could have the following interface:
|
||||
std::pair<char,bool> get_async_input();
|
||||
std::pair<point,bool> polygon::get_any_point_effectively_inside();
|
||||
|
||||
These functions use a consistent interface for dealing with possibly nonexistent
|
||||
These functions use a consistent interface for dealing with possibly inexistent
|
||||
results:
|
||||
|
||||
std::pair<point,bool> p = poly.get_any_point_effectively_inside();
|
||||
|
||||
@ -11,8 +11,6 @@
|
||||
|
||||
[section Synopsis]
|
||||
|
||||
```// In Header: <`[@boost:/boost/optional/optional.hpp boost/optional/optional.hpp]'''<phrase role="comment">></phrase>'''``
|
||||
|
||||
namespace boost {
|
||||
|
||||
template<class T>
|
||||
@ -47,9 +45,9 @@
|
||||
|
||||
template<class U> optional& operator = ( optional<U> const& rhs ) ; ``[link reference_optional_operator_equal_other_optional __GO_TO__]``
|
||||
|
||||
template<class InPlaceFactory> optional& operator = ( InPlaceFactory const& f ) ; ``[link reference_optional_operator_equal_factory __GO_TO__]``
|
||||
template<class InPlaceFactory> optional& operator = ( InPlaceFactory const& f ) ; ``[/[link reference_optional_operator_equal_factory __GO_TO__]]``
|
||||
|
||||
template<class TypedInPlaceFactory> optional& operator = ( TypedInPlaceFactory const& f ) ; ``[link reference_optional_operator_equal_factory __GO_TO__]``
|
||||
template<class TypedInPlaceFactory> optional& operator = ( TypedInPlaceFactory const& f ) ; ``[/[link reference_optional_operator_equal_factory __GO_TO__]]``
|
||||
|
||||
T const& get() const ; ``[link reference_optional_get __GO_TO__]``
|
||||
T& get() ; ``[link reference_optional_get __GO_TO__]``
|
||||
@ -234,7 +232,7 @@ __SPACE__
|
||||
|
||||
* otherwise, same as:
|
||||
|
||||
[: `optional<T `['(not a ref)]`>::optional()`]
|
||||
[: `optional<T ['(not a ref)]>::optional()`]
|
||||
[: `optional<T&> ::optional()`]
|
||||
|
||||
__SPACE__
|
||||
@ -381,12 +379,12 @@ assert ( *opt == y ) ;
|
||||
|
||||
__SPACE__
|
||||
|
||||
[: `optional<T&>& optional<T&>::operator= ( T& rhs ) ;`]
|
||||
[: `optional<T&>& optional<T&>::operator= ( T& const& rhs ) ;`]
|
||||
|
||||
* [*Effect:] (Re)binds the wrapped reference.
|
||||
* [*Effect:] (Re)binds thee wrapped reference.
|
||||
* [*Postconditions: ] `*this` is initialized and it references the same
|
||||
object referenced by `rhs`.
|
||||
* [*Notes:] If `*this` was initialized, it is ['rebound] to the new object.
|
||||
* [*Notes:] If `*this` was initialized, is 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 +443,7 @@ __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 ['rebound] to
|
||||
* [*Notes:] If `*this` was initialized and so is *rhs, this is is ['rebound] to
|
||||
the new object. See [link boost_optional.rebinding_semantics_for_assignment_of_optional_references here] for details on this behavior.
|
||||
* [*Example:]
|
||||
``
|
||||
@ -502,23 +500,6 @@ assert ( *opt1 == static_cast<U>(v) ) ;
|
||||
|
||||
__SPACE__
|
||||
|
||||
[#reference_optional_operator_equal_factory]
|
||||
|
||||
[: `template<InPlaceFactory> optional<T>& optional<T` ['(not a ref)]`>::operator=( InPlaceFactory const& f );`]
|
||||
[: `template<TypedInPlaceFactory> optional<T>& optional<T` ['(not a ref)]`>::operator=( TypedInPlaceFactory const& f );`]
|
||||
|
||||
* [*Effect:] Assigns an `optional` with a value of `T` obtained from the
|
||||
factory.
|
||||
* [*Postconditions: ] `*this` is [_initialized] and its value is ['directly given]
|
||||
from the factory `f` (i.e., the value [_is not copied]).
|
||||
* [*Throws:] Whatever the `T` constructor called by the factory throws.
|
||||
* [*Notes:] See [link boost_optional.in_place_factories In-Place Factories]
|
||||
* [*Exception Safety:] Exceptions can only be thrown during the call to
|
||||
the `T` constructor used by the factory; in that case, the `optional` object
|
||||
will be reset to be ['uninitialized].
|
||||
|
||||
__SPACE__
|
||||
|
||||
[#reference_optional_reset_value]
|
||||
|
||||
[: `void optional<T` ['(not a ref)]`>::reset( T const& v ) ;`]
|
||||
@ -660,7 +641,7 @@ __SPACE__
|
||||
[: `optional<T>::operator `['unspecified-bool-type]`() const ;`]
|
||||
|
||||
* [*Returns:] An unspecified value which if used on a boolean context
|
||||
is equivalent to (`get_ptr() != 0`)
|
||||
is equivalent to (`get() != 0`)
|
||||
* [*Throws:] Nothing.
|
||||
* [*Example:]
|
||||
``
|
||||
@ -697,7 +678,15 @@ __SPACE__
|
||||
|
||||
[: `bool optional<T>::is_initialized() const ;`]
|
||||
|
||||
* [*Deprecated:] Same as `operator `['unspecified-bool-type]`() ;`
|
||||
* [*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() );
|
||||
``
|
||||
|
||||
__SPACE__
|
||||
|
||||
|
||||
@ -1,4 +1,4 @@
|
||||
|
||||
|
||||
[section Optional references]
|
||||
|
||||
This library allows the template parameter `T` to be of reference type:
|
||||
@ -37,7 +37,7 @@ the first time) to the object. Clearly, there is no other choice.
|
||||
assert(x==2);
|
||||
|
||||
If you assign to a bare C++ reference, the assignment is forwarded to the
|
||||
referenced object; its value changes but the reference is never rebound.
|
||||
referenced object; it's value changes but the reference is never rebound.
|
||||
|
||||
int a = 1 ;
|
||||
int& ra = a ;
|
||||
@ -95,15 +95,15 @@ use Optional's assignment without explicitly handling the previous
|
||||
initialization state unless your code is capable of functioning whether
|
||||
after the assignment, `a` aliases the same object as `b` or not.
|
||||
|
||||
That is, you would have to discriminate in order to be consistent.
|
||||
That is, you would have to discriminate in order to be consistency.
|
||||
|
||||
If in your code rebinding to another object is not an option, then it is very
|
||||
likely that binding for the first time isn't either. In such case, assignment
|
||||
If in your code rebinding to another object is not an option, then is very
|
||||
likely that binding for the fist time isn't either. In such case, assignment
|
||||
to an ['uninitialized ] `optional<T&>` shall be prohibited. It is quite possible
|
||||
that in such a scenario it is a precondition that the lvalue must be already
|
||||
initialized. If it isn't, then binding for the first time is OK
|
||||
that in such scenario the precondition that the lvalue must be already
|
||||
initialized exist. If it doesn't, then binding for the first time is OK
|
||||
while rebinding is not which is IMO very unlikely.
|
||||
In such a scenario, you can assign the value itself directly, as in:
|
||||
In such scenario, you can assign the value itself directly, as in:
|
||||
|
||||
assert(!!opt);
|
||||
*opt=value;
|
||||
@ -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]
|
||||
|
||||
@ -4,7 +4,7 @@
|
||||
// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
|
||||
// http://www.boost.org/LICENSE_1_0.txt)
|
||||
//
|
||||
// See http://www.boost.org/libs/optional for documentation.
|
||||
// See http://www.boost.org/lib/optional for documentation.
|
||||
//
|
||||
// You are welcome to contact the author at:
|
||||
// fernando_cacciola@hotmail.com
|
||||
|
||||
@ -4,7 +4,7 @@
|
||||
// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
|
||||
// http://www.boost.org/LICENSE_1_0.txt)
|
||||
//
|
||||
// See http://www.boost.org/libs/optional for documentation.
|
||||
// See http://www.boost.org/lib/optional for documentation.
|
||||
//
|
||||
// You are welcome to contact the author at:
|
||||
// fernando_cacciola@hotmail.com
|
||||
@ -17,27 +17,24 @@
|
||||
|
||||
#include<new>
|
||||
#include<algorithm>
|
||||
#include <iosfwd>
|
||||
|
||||
#include <boost/config.hpp>
|
||||
#include <boost/assert.hpp>
|
||||
#include <boost/type.hpp>
|
||||
#include <boost/type_traits/alignment_of.hpp>
|
||||
#include <boost/type_traits/has_nothrow_constructor.hpp>
|
||||
#include <boost/type_traits/type_with_alignment.hpp>
|
||||
#include <boost/type_traits/remove_reference.hpp>
|
||||
#include <boost/type_traits/is_reference.hpp>
|
||||
#include <boost/mpl/if.hpp>
|
||||
#include <boost/mpl/bool.hpp>
|
||||
#include <boost/mpl/not.hpp>
|
||||
#include <boost/detail/reference_content.hpp>
|
||||
#include <boost/none.hpp>
|
||||
#include <boost/utility/swap.hpp>
|
||||
#include <boost/utility/addressof.hpp>
|
||||
#include <boost/utility/compare_pointees.hpp>
|
||||
#include <boost/utility/in_place_factory.hpp>
|
||||
#include "boost/config.hpp"
|
||||
#include "boost/assert.hpp"
|
||||
#include "boost/type.hpp"
|
||||
#include "boost/type_traits/alignment_of.hpp"
|
||||
#include "boost/type_traits/has_nothrow_constructor.hpp"
|
||||
#include "boost/type_traits/type_with_alignment.hpp"
|
||||
#include "boost/type_traits/remove_reference.hpp"
|
||||
#include "boost/type_traits/is_reference.hpp"
|
||||
#include "boost/mpl/if.hpp"
|
||||
#include "boost/mpl/bool.hpp"
|
||||
#include "boost/mpl/not.hpp"
|
||||
#include "boost/detail/reference_content.hpp"
|
||||
#include "boost/none.hpp"
|
||||
#include "boost/utility/compare_pointees.hpp"
|
||||
#include "boost/utility/in_place_factory.hpp"
|
||||
|
||||
#include <boost/optional/optional_fwd.hpp>
|
||||
#include "boost/optional/optional_fwd.hpp"
|
||||
|
||||
#if BOOST_WORKAROUND(BOOST_MSVC, == 1200)
|
||||
// VC6.0 has the following bug:
|
||||
@ -84,15 +81,6 @@
|
||||
#define BOOST_OPTIONAL_WEAK_OVERLOAD_RESOLUTION
|
||||
#endif
|
||||
|
||||
#if defined(__GNUC__) && (__GNUC__ * 100 + __GNUC_MINOR__) > 302 \
|
||||
&& !defined(__INTEL_COMPILER)
|
||||
// GCC since 3.3 has may_alias attribute that helps to alleviate optimizer issues with
|
||||
// regard to violation of the strict aliasing rules. The optional< T > storage type is marked
|
||||
// with this attribute in order to let the compiler know that it will alias objects of type T
|
||||
// and silence compilation warnings.
|
||||
#define BOOST_OPTIONAL_DETAIL_USE_ATTRIBUTE_MAY_ALIAS
|
||||
#endif
|
||||
|
||||
// Daniel Wallin discovered that bind/apply.hpp badly interacts with the apply<>
|
||||
// member template of a factory as used in the optional<> implementation.
|
||||
// He proposed this simple fix which is to move the call to apply<> outside
|
||||
@ -100,7 +88,7 @@
|
||||
namespace boost_optional_detail
|
||||
{
|
||||
template <class T, class Factory>
|
||||
inline void construct(Factory const& factory, void* address)
|
||||
void construct(Factory const& factory, void* address)
|
||||
{
|
||||
factory.BOOST_NESTED_TEMPLATE apply<T>(address);
|
||||
}
|
||||
@ -112,9 +100,6 @@ namespace boost {
|
||||
class in_place_factory_base ;
|
||||
class typed_in_place_factory_base ;
|
||||
|
||||
// This forward is needed to refer to namespace scope swap from the member swap
|
||||
template<class T> void swap ( optional<T>& x, optional<T>& y );
|
||||
|
||||
namespace optional_detail {
|
||||
|
||||
// This local class is used instead of that in "aligned_storage.hpp"
|
||||
@ -125,12 +110,7 @@ template <class T>
|
||||
class aligned_storage
|
||||
{
|
||||
// Borland ICEs if unnamed unions are used for this!
|
||||
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__))
|
||||
#endif
|
||||
dummy_u
|
||||
union dummy_u
|
||||
{
|
||||
char data[ sizeof(T) ];
|
||||
BOOST_DEDUCED_TYPENAME type_with_alignment<
|
||||
@ -139,13 +119,8 @@ class aligned_storage
|
||||
|
||||
public:
|
||||
|
||||
#if defined(BOOST_OPTIONAL_DETAIL_USE_ATTRIBUTE_MAY_ALIAS)
|
||||
void const* address() const { return &dummy_; }
|
||||
void * address() { return &dummy_; }
|
||||
#else
|
||||
void const* address() const { return dummy_.data; }
|
||||
void * address() { return dummy_.data; }
|
||||
#endif
|
||||
void const* address() const { return &dummy_.data[0]; }
|
||||
void * address() { return &dummy_.data[0]; }
|
||||
} ;
|
||||
|
||||
template<class T>
|
||||
@ -451,22 +426,8 @@ class optional_base : public optional_tag
|
||||
private :
|
||||
|
||||
// internal_type can be either T or reference_content<T>
|
||||
#if defined(BOOST_OPTIONAL_DETAIL_USE_ATTRIBUTE_MAY_ALIAS)
|
||||
// This workaround is supposed to silence GCC warnings about broken strict aliasing rules
|
||||
internal_type const* get_object() const
|
||||
{
|
||||
union { void const* ap_pvoid; internal_type const* as_ptype; } caster = { m_storage.address() };
|
||||
return caster.as_ptype;
|
||||
}
|
||||
internal_type * get_object()
|
||||
{
|
||||
union { void* ap_pvoid; internal_type* as_ptype; } caster = { m_storage.address() };
|
||||
return caster.as_ptype;
|
||||
}
|
||||
#else
|
||||
internal_type const* get_object() const { return static_cast<internal_type const*>(m_storage.address()); }
|
||||
internal_type * get_object() { return static_cast<internal_type *> (m_storage.address()); }
|
||||
#endif
|
||||
|
||||
// reference_content<T> lacks an implicit conversion to T&, so the following is needed to obtain a proper reference.
|
||||
reference_const_type dereference( internal_type const* p, is_not_reference_tag ) const { return *p ; }
|
||||
@ -477,7 +438,7 @@ 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() ; m_initialized = false ; }
|
||||
void destroy_impl ( is_not_reference_tag ) { get_ptr_impl()->T::~T() ; m_initialized = false ; }
|
||||
#endif
|
||||
|
||||
void destroy_impl ( is_reference_tag ) { m_initialized = false ; }
|
||||
@ -557,7 +518,7 @@ class optional : public optional_detail::optional_base<T>
|
||||
// Depending on the above some T ctor is called.
|
||||
// Can throw is the resolved T ctor throws.
|
||||
template<class Expr>
|
||||
explicit optional ( Expr const& expr ) : base(expr,boost::addressof(expr)) {}
|
||||
explicit optional ( Expr const& expr ) : base(expr,&expr) {}
|
||||
#endif
|
||||
|
||||
// Creates a deep copy of another optional<T>
|
||||
@ -571,9 +532,9 @@ class optional : public optional_detail::optional_base<T>
|
||||
// Assigns from an expression. See corresponding constructor.
|
||||
// Basic Guarantee: If the resolved T ctor throws, this is left UNINITIALIZED
|
||||
template<class Expr>
|
||||
optional& operator= ( Expr const& expr )
|
||||
optional& operator= ( Expr expr )
|
||||
{
|
||||
this->assign_expr(expr,boost::addressof(expr));
|
||||
this->assign_expr(expr,&expr);
|
||||
return *this ;
|
||||
}
|
||||
#endif
|
||||
@ -744,11 +705,6 @@ 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.
|
||||
|
||||
@ -896,12 +852,12 @@ bool operator >= ( optional<T> const& x, none_t y )
|
||||
|
||||
template<class T>
|
||||
inline
|
||||
bool operator == ( none_t , optional<T> const& y )
|
||||
bool operator == ( none_t x, optional<T> const& y )
|
||||
{ return equal_pointees(optional<T>() ,y); }
|
||||
|
||||
template<class T>
|
||||
inline
|
||||
bool operator < ( none_t , optional<T> const& y )
|
||||
bool operator < ( none_t x, optional<T> const& y )
|
||||
{ return less_pointees(optional<T>() ,y); }
|
||||
|
||||
template<class T>
|
||||
@ -924,8 +880,19 @@ inline
|
||||
bool operator >= ( none_t x, optional<T> const& y )
|
||||
{ return !( x < y ) ; }
|
||||
|
||||
//
|
||||
// The following swap implementation follows the GCC workaround as found in
|
||||
// "boost/detail/compressed_pair.hpp"
|
||||
//
|
||||
namespace optional_detail {
|
||||
|
||||
// GCC < 3.2 gets the using declaration at namespace scope (FLC, DWA)
|
||||
#if BOOST_WORKAROUND(__GNUC__, < 3) \
|
||||
|| BOOST_WORKAROUND(__GNUC__, == 3) && __GNUC_MINOR__ <= 2
|
||||
using std::swap;
|
||||
#define BOOST_OPTIONAL_STD_SWAP_INTRODUCED_AT_NS_SCOPE
|
||||
#endif
|
||||
|
||||
template<bool use_default_constructor> struct swap_selector;
|
||||
|
||||
template<>
|
||||
@ -934,8 +901,8 @@ struct swap_selector<true>
|
||||
template<class T>
|
||||
static void optional_swap ( optional<T>& x, optional<T>& y )
|
||||
{
|
||||
const bool hasX = !!x;
|
||||
const bool hasY = !!y;
|
||||
bool hasX = x;
|
||||
bool hasY = y;
|
||||
|
||||
if ( !hasX && !hasY )
|
||||
return;
|
||||
@ -945,8 +912,12 @@ struct swap_selector<true>
|
||||
else if ( !hasY )
|
||||
y = boost::in_place();
|
||||
|
||||
// Boost.Utility.Swap will take care of ADL and workarounds for broken compilers
|
||||
boost::swap(x.get(),y.get());
|
||||
// GCC > 3.2 and all other compilers have the using declaration at function scope (FLC)
|
||||
#ifndef BOOST_OPTIONAL_STD_SWAP_INTRODUCED_AT_NS_SCOPE
|
||||
// allow for Koenig lookup
|
||||
using std::swap ;
|
||||
#endif
|
||||
swap(*x,*y);
|
||||
|
||||
if( !hasX )
|
||||
y = boost::none ;
|
||||
@ -961,23 +932,24 @@ struct swap_selector<false>
|
||||
template<class T>
|
||||
static void optional_swap ( optional<T>& x, optional<T>& y )
|
||||
{
|
||||
const bool hasX = !!x;
|
||||
const bool hasY = !!y;
|
||||
|
||||
if ( !hasX && hasY )
|
||||
if ( !x && !!y )
|
||||
{
|
||||
x = y.get();
|
||||
x = *y;
|
||||
y = boost::none ;
|
||||
}
|
||||
else if ( hasX && !hasY )
|
||||
else if ( !!x && !y )
|
||||
{
|
||||
y = x.get();
|
||||
y = *x ;
|
||||
x = boost::none ;
|
||||
}
|
||||
else if ( hasX && hasY )
|
||||
else if ( !!x && !!y )
|
||||
{
|
||||
// Boost.Utility.Swap will take care of ADL and workarounds for broken compilers
|
||||
boost::swap(x.get(),y.get());
|
||||
// GCC > 3.2 and all other compilers have the using declaration at function scope (FLC)
|
||||
#ifndef BOOST_OPTIONAL_STD_SWAP_INTRODUCED_AT_NS_SCOPE
|
||||
// allow for Koenig lookup
|
||||
using std::swap ;
|
||||
#endif
|
||||
swap(*x,*y);
|
||||
}
|
||||
}
|
||||
};
|
||||
@ -995,3 +967,4 @@ template<class T> inline void swap ( optional<T>& x, optional<T>& y )
|
||||
} // namespace boost
|
||||
|
||||
#endif
|
||||
|
||||
|
||||
@ -4,7 +4,7 @@
|
||||
// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
|
||||
// http://www.boost.org/LICENSE_1_0.txt)
|
||||
//
|
||||
// See http://www.boost.org/libs/optional for documentation.
|
||||
// See http://www.boost.org/lib/optional for documentation.
|
||||
//
|
||||
// You are welcome to contact the author at:
|
||||
// fernando_cacciola@hotmail.com
|
||||
|
||||
@ -4,7 +4,7 @@
|
||||
// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
|
||||
// http://www.boost.org/LICENSE_1_0.txt)
|
||||
//
|
||||
// See http://www.boost.org/libs/optional for documentation.
|
||||
// See http://www.boost.org/lib/optional for documentation.
|
||||
//
|
||||
// You are welcome to contact the author at:
|
||||
// fernando_cacciola@hotmail.com
|
||||
@ -25,8 +25,7 @@
|
||||
# include <ostream>
|
||||
#endif
|
||||
|
||||
#include <boost/none.hpp>
|
||||
#include <boost/assert.hpp>
|
||||
|
||||
#include "boost/optional/optional.hpp"
|
||||
#include "boost/utility/value_init.hpp"
|
||||
|
||||
@ -73,20 +72,7 @@ operator>>(std::basic_istream<CharType, CharTrait>& in, optional<T>& v)
|
||||
v = x ;
|
||||
}
|
||||
else
|
||||
{
|
||||
if (d == '-')
|
||||
{
|
||||
d = in.get();
|
||||
|
||||
if (d == '-')
|
||||
{
|
||||
v = none;
|
||||
return in;
|
||||
}
|
||||
}
|
||||
|
||||
in.setstate( std::ios::failbit );
|
||||
}
|
||||
v = optional<T>() ;
|
||||
}
|
||||
|
||||
return in;
|
||||
|
||||
@ -840,21 +840,11 @@ 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) );
|
||||
@ -1273,33 +1263,6 @@ void test_swap_tweaking()
|
||||
BOOST_CHECK( test_swap_member_function( ARG(optional_swap_test::template_whose_default_ctor_should_be_used<char>) ) );
|
||||
}
|
||||
|
||||
// Test for support for classes with overridden operator&
|
||||
class CustomAddressOfClass
|
||||
{
|
||||
int n;
|
||||
|
||||
public:
|
||||
CustomAddressOfClass() : n(0) {}
|
||||
CustomAddressOfClass(CustomAddressOfClass const& that) : n(that.n) {}
|
||||
explicit CustomAddressOfClass(int m) : n(m) {}
|
||||
int* operator& () { return &n; }
|
||||
bool operator== (CustomAddressOfClass const& that) const { return n == that.n; }
|
||||
};
|
||||
|
||||
void test_custom_addressof_operator()
|
||||
{
|
||||
boost::optional< CustomAddressOfClass > o1(CustomAddressOfClass(10));
|
||||
BOOST_CHECK(!!o1);
|
||||
BOOST_CHECK(o1.get() == CustomAddressOfClass(10));
|
||||
|
||||
o1 = CustomAddressOfClass(20);
|
||||
BOOST_CHECK(!!o1);
|
||||
BOOST_CHECK(o1.get() == CustomAddressOfClass(20));
|
||||
|
||||
o1 = boost::none;
|
||||
BOOST_CHECK(!o1);
|
||||
}
|
||||
|
||||
int test_main( int, char* [] )
|
||||
{
|
||||
try
|
||||
@ -1310,7 +1273,6 @@ int test_main( int, char* [] )
|
||||
test_conversions1();
|
||||
test_conversions2();
|
||||
test_swap_tweaking();
|
||||
test_custom_addressof_operator();
|
||||
}
|
||||
catch ( ... )
|
||||
{
|
||||
|
||||
@ -55,14 +55,10 @@ void test2( Opt o, Opt buff )
|
||||
{
|
||||
stringstream s ;
|
||||
|
||||
const int markv = 123 ;
|
||||
int mark = 0 ;
|
||||
|
||||
s << o << " " << markv ;
|
||||
s >> buff >> mark ;
|
||||
s << o ;
|
||||
s >> buff ;
|
||||
|
||||
BOOST_ASSERT( buff == o ) ;
|
||||
BOOST_ASSERT( mark == markv ) ;
|
||||
}
|
||||
|
||||
|
||||
@ -81,6 +77,7 @@ int test_main( int, char* [] )
|
||||
{
|
||||
test(1,2);
|
||||
test(string("hello"),string("buffer"));
|
||||
test(string(""),string("buffer"));
|
||||
}
|
||||
catch ( ... )
|
||||
{
|
||||
|
||||
Reference in New Issue
Block a user