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9 files changed, 1141 insertions, 587 deletions
diff --git a/libs/scope_exit/doc/html/scope_exit/acknowledge.html b/libs/scope_exit/doc/html/scope_exit/acknowledge.html deleted file mode 100644 index f880308b28..0000000000 --- a/libs/scope_exit/doc/html/scope_exit/acknowledge.html +++ /dev/null @@ -1,66 +0,0 @@ -<html> -<head> -<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII"> -<title>Acknowledge</title> -<link rel="stylesheet" href="../../../../../doc/src/boostbook.css" type="text/css"> -<meta name="generator" content="DocBook XSL Stylesheets V1.75.2"> -<link rel="home" href="../index.html" title="Chapter 1. Boost.ScopeExit"> -<link rel="up" href="../index.html" title="Chapter 1. Boost.ScopeExit"> -<link rel="prev" href="ref.html" title="Reference"> -</head> -<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> -<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="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="ref.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.html"><img src="../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../../../doc/src/images/home.png" alt="Home"></a> -</div> -<div class="section"> -<div class="titlepage"><div><div><h2 class="title" style="clear: both"> -<a name="scope_exit.acknowledge"></a> Acknowledge</h2></div></div></div> -<p> - (in chronological order) - </p> -<p> - Maxim Yegorushkin for sending me a code where he used a local struct to clean - up resources. - </p> -<p> - Andrei Alexandrescu for pointing me to <a href="http://www.digitalmars.com/d/2.0/statement.html#ScopeGuardStatement" target="_top">scope(exit)</a> - construct of the <a href="http://www.digitalmars.com/d/index.html" target="_top">D</a> - programming language. - </p> -<p> - Pavel Vozenilek and Maxim Yanchenko for reviews of early drafts of the library. - </p> -<p> - Steven Watanabe for his valuable ideas. - </p> -<p> - Jody Hagins for good comments that helped to significantly improve the documentation. - </p> -<p> - Richard Webb for testing the library on MSVC compiler. - </p> -</div> -<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> -<td align="left"></td> -<td align="right"><div class="copyright-footer">Copyright © 2006 -2009 Alexander Nasonov<p> - Distributed under the Boost Software License, Version 1.0. (See accompanying - file LICENSE_1_0.txt or copy at <ulink url="http://www.boost.org/LICENSE_1_0.txt"> - http://www.boost.org/LICENSE_1_0.txt </ulink>) - </p> -</div></td> -</tr></table> -<hr> -<div class="spirit-nav"> -<a accesskey="p" href="ref.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.html"><img src="../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../../../doc/src/images/home.png" alt="Home"></a> -</div> -</body> -</html> diff --git a/libs/scope_exit/doc/html/scope_exit/acknowledgements.html b/libs/scope_exit/doc/html/scope_exit/acknowledgements.html new file mode 100644 index 0000000000..830865af82 --- /dev/null +++ b/libs/scope_exit/doc/html/scope_exit/acknowledgements.html @@ -0,0 +1,75 @@ +<html> +<head> +<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII"> +<title>Acknowledgements</title> +<link rel="stylesheet" href="../../../../../doc/src/boostbook.css" type="text/css"> +<meta name="generator" content="DocBook XSL Stylesheets V1.76.1"> +<link rel="home" href="../index.html" title="Chapter 1. Boost.ScopeExit 1.1.0"> +<link rel="up" href="../index.html" title="Chapter 1. Boost.ScopeExit 1.1.0"> +<link rel="prev" href="../BOOST_SCOPE_EXIT_CONFIG_USE_LAMBDAS.html" title="Macro BOOST_SCOPE_EXIT_CONFIG_USE_LAMBDAS"> +</head> +<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> +<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="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="../BOOST_SCOPE_EXIT_CONFIG_USE_LAMBDAS.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.html"><img src="../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../../../doc/src/images/home.png" alt="Home"></a> +</div> +<div class="section scope_exit_acknowledgements"> +<div class="titlepage"><div><div><h2 class="title" style="clear: both"> +<a name="scope_exit.acknowledgements"></a><a class="link" href="acknowledgements.html" title="Acknowledgements">Acknowledgements</a> +</h2></div></div></div> +<p> + Alexander Nasonov is the original library author. + </p> +<p> + Lorenzo Caminiti added variadic macro support, capture of the object <code class="computeroutput"><span class="identifier">this_</span></code>, empty captures using <code class="computeroutput"><span class="keyword">void</span></code>, and <code class="computeroutput"><span class="identifier">BOOST_SCOPE_EXIT_ALL</span></code>. + </p> +<p> + Thanks to the following people (in chronological order): + </p> +<p> + Maxim Yegorushkin for sharing code where he used a local struct to clean up + resources; + </p> +<p> + Andrei Alexandrescu for pointing out the <a href="http://www.digitalmars.com/d/2.0/statement.html#ScopeGuardStatement" target="_top">scope(exit)</a> + construct of the <a href="http://www.digitalmars.com/d/index.html" target="_top">D</a> + programming language; + </p> +<p> + Pavel Vozenilek and Maxim Yanchenko for reviews of early drafts of the library; + </p> +<p> + Steven Watanabe for his valuable ideas; + </p> +<p> + Jody Hagins for good comments that helped to significantly improve the documentation; + </p> +<p> + Richard Webb for testing the library on MSVC compiler; + </p> +<p> + Adam Butcher for a workaround to error C2355 when deducing the type of <code class="computeroutput"><span class="keyword">this</span></code> on some MSVC versions. + </p> +</div> +<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> +<td align="left"></td> +<td align="right"><div class="copyright-footer">Copyright © 2006-2012 Alexander Nasonov, Lorenzo Caminiti<p> + Distributed under the Boost Software License, Version 1.0 (see accompanying + file LICENSE_1_0.txt or a copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>) + </p> +</div></td> +</tr></table> +<hr> +<div class="spirit-nav"> +<a accesskey="p" href="../BOOST_SCOPE_EXIT_CONFIG_USE_LAMBDAS.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.html"><img src="../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../../../doc/src/images/home.png" alt="Home"></a> +</div> +</body> +</html> diff --git a/libs/scope_exit/doc/html/scope_exit/alternatives.html b/libs/scope_exit/doc/html/scope_exit/alternatives.html index 549af9f164..91f6ba286d 100644 --- a/libs/scope_exit/doc/html/scope_exit/alternatives.html +++ b/libs/scope_exit/doc/html/scope_exit/alternatives.html @@ -1,13 +1,13 @@ <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=US-ASCII"> -<title>Alternatives</title> +<title>Annex: Alternatives</title> <link rel="stylesheet" href="../../../../../doc/src/boostbook.css" type="text/css"> -<meta name="generator" content="DocBook XSL Stylesheets V1.75.2"> -<link rel="home" href="../index.html" title="Chapter 1. Boost.ScopeExit"> -<link rel="up" href="../index.html" title="Chapter 1. Boost.ScopeExit"> +<meta name="generator" content="DocBook XSL Stylesheets V1.76.1"> +<link rel="home" href="../index.html" title="Chapter 1. Boost.ScopeExit 1.1.0"> +<link rel="up" href="../index.html" title="Chapter 1. Boost.ScopeExit 1.1.0"> <link rel="prev" href="tutorial.html" title="Tutorial"> -<link rel="next" href="compilers.html" title="Supported Compilers"> +<link rel="next" href="no_variadic_macros.html" title="Annex: No Variadic Macros"> </head> <body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> <table cellpadding="2" width="100%"><tr> @@ -20,85 +20,94 @@ </tr></table> <hr> <div class="spirit-nav"> -<a accesskey="p" href="tutorial.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="compilers.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a> +<a accesskey="p" href="tutorial.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="no_variadic_macros.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a> </div> -<div class="section"> +<div class="section scope_exit_alternatives"> <div class="titlepage"><div><div><h2 class="title" style="clear: both"> -<a name="scope_exit.alternatives"></a> Alternatives</h2></div></div></div> -<a name="alternatives.try_catch"></a><h4> -<a name="id761016"></a> - try-catch +<a name="scope_exit.alternatives"></a><a class="link" href="alternatives.html" title="Annex: Alternatives">Annex: Alternatives</a> +</h2></div></div></div> +<p> + This section presents some alternative and related work to <a class="link" href="../index.html" title="Chapter 1. Boost.ScopeExit 1.1.0">Boost.ScopeExit</a>. + </p> +<h4> +<a name="scope_exit.alternatives.h0"></a> + <span><a name="scope_exit.alternatives.try_catch"></a></span><a class="link" href="alternatives.html#scope_exit.alternatives.try_catch">Try-Catch</a> </h4> <p> - This is an example of using a badly designed <code class="computeroutput"><span class="identifier">File</span></code> - class. An instance of <code class="computeroutput"><span class="identifier">File</span></code> - doesn't close a file in a destructor, a programmer is expected to call the - <code class="computeroutput"><span class="identifier">close</span></code> member function explicitly. + This is an example of using a badly designed <code class="computeroutput"><span class="identifier">file</span></code> + class. An instance of <code class="computeroutput"><span class="identifier">file</span></code> + does not close the file in its destructor, a programmer is expected to call + the <code class="computeroutput"><span class="identifier">close</span></code> member function explicitly. + For example (see also <a href="../../../example/try_catch.cpp" target="_top"><code class="literal">try_catch.cpp</code></a>): </p> -<pre class="programlisting"><span class="identifier">File</span> <span class="identifier">passwd</span><span class="special">;</span> +<p> +</p> +<pre class="programlisting"><span class="identifier">file</span> <span class="identifier">passwd</span><span class="special">;</span> <span class="keyword">try</span> <span class="special">{</span> <span class="identifier">passwd</span><span class="special">.</span><span class="identifier">open</span><span class="special">(</span><span class="string">"/etc/passwd"</span><span class="special">);</span> - <span class="comment">// ... -</span> <span class="identifier">passwd</span><span class="special">.</span><span class="identifier">close</span><span class="special">();</span> -<span class="special">}</span> -<span class="keyword">catch</span><span class="special">(...)</span> <span class="special">{</span> - <span class="identifier">log</span><span class="special">(</span><span class="string">"could not get user info"</span><span class="special">);</span> - <span class="keyword">if</span><span class="special">(</span><span class="identifier">passwd</span><span class="special">.</span><span class="identifier">is_open</span><span class="special">())</span> - <span class="identifier">passwd</span><span class="special">.</span><span class="identifier">close</span><span class="special">();</span> + <span class="comment">// ...</span> + <span class="identifier">passwd</span><span class="special">.</span><span class="identifier">close</span><span class="special">();</span> +<span class="special">}</span> <span class="keyword">catch</span><span class="special">(...)</span> <span class="special">{</span> + <span class="identifier">std</span><span class="special">::</span><span class="identifier">clog</span> <span class="special"><<</span> <span class="string">"could not get user info"</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span> + <span class="keyword">if</span><span class="special">(</span><span class="identifier">passwd</span><span class="special">.</span><span class="identifier">is_open</span><span class="special">())</span> <span class="identifier">passwd</span><span class="special">.</span><span class="identifier">close</span><span class="special">();</span> <span class="keyword">throw</span><span class="special">;</span> <span class="special">}</span> </pre> <p> - Note the following: </p> -<div class="itemizedlist"><ul class="itemizedlist" type="disc"> +<p> + Note the following issues with this approach: + </p> +<div class="orderedlist"><ol class="orderedlist" type="1"> <li class="listitem"> - the <code class="computeroutput"><span class="identifier">passwd</span></code> object is defined + The <code class="computeroutput"><span class="identifier">passwd</span></code> object is defined outside of the <code class="computeroutput"><span class="keyword">try</span></code> block because this object is required inside the <code class="computeroutput"><span class="keyword">catch</span></code> - block to close the file, + block to close the file. </li> <li class="listitem"> - the <code class="computeroutput"><span class="identifier">passwd</span></code> object is not + The <code class="computeroutput"><span class="identifier">passwd</span></code> object is not fully constructed until after the <code class="computeroutput"><span class="identifier">open</span></code> - member function returns, and + member function returns. </li> <li class="listitem"> - if opening throws, the <code class="computeroutput"><span class="identifier">passwd</span><span class="special">.</span><span class="identifier">close</span><span class="special">()</span></code> should not be called, hence the call + If opening throws, the <code class="computeroutput"><span class="identifier">passwd</span><span class="special">.</span><span class="identifier">close</span><span class="special">()</span></code> should not be called, hence the call to <code class="computeroutput"><span class="identifier">passwd</span><span class="special">.</span><span class="identifier">is_open</span><span class="special">()</span></code>. </li> -</ul></div> +</ol></div> <p> - <a class="link" href="../index.html" title="Chapter 1. Boost.ScopeExit">ScopeExit</a> doesn't have any of these problems: + The <a class="link" href="../index.html" title="Chapter 1. Boost.ScopeExit 1.1.0">Boost.ScopeExit</a> approach does not have + any of these issues. For example (see also <a href="../../../example/try_catch.cpp" target="_top"><code class="literal">try_catch.cpp</code></a>): </p> +<p> +</p> <pre class="programlisting"><span class="keyword">try</span> <span class="special">{</span> - <span class="identifier">File</span> <span class="identifier">passwd</span><span class="special">(</span><span class="string">"/etc/passwd"</span><span class="special">);</span> - <span class="identifier">BOOST_SCOPE_EXIT</span><span class="special">(</span> <span class="special">(&</span><span class="identifier">passwd</span><span class="special">)</span> <span class="special">)</span> <span class="special">{</span> + <span class="identifier">file</span> <span class="identifier">passwd</span><span class="special">(</span><span class="string">"/etc/passwd"</span><span class="special">);</span> + <span class="identifier">BOOST_SCOPE_EXIT</span><span class="special">(&</span><span class="identifier">passwd</span><span class="special">)</span> <span class="special">{</span> <span class="identifier">passwd</span><span class="special">.</span><span class="identifier">close</span><span class="special">();</span> <span class="special">}</span> <span class="identifier">BOOST_SCOPE_EXIT_END</span> - <span class="comment">// ... -</span><span class="special">}</span> -<span class="keyword">catch</span><span class="special">(...)</span> <span class="special">{</span> - <span class="identifier">log</span><span class="special">(</span><span class="string">"could not get user info"</span><span class="special">);</span> +<span class="special">}</span> <span class="keyword">catch</span><span class="special">(...)</span> <span class="special">{</span> + <span class="identifier">std</span><span class="special">::</span><span class="identifier">clog</span> <span class="special"><<</span> <span class="string">"could not get user info"</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span> <span class="keyword">throw</span><span class="special">;</span> <span class="special">}</span> </pre> -<a name="alternatives.raii"></a><h4> -<a name="id761495"></a> - RAII +<p> + </p> +<h4> +<a name="scope_exit.alternatives.h1"></a> + <span><a name="scope_exit.alternatives.raii"></a></span><a class="link" href="alternatives.html#scope_exit.alternatives.raii">RAII</a> </h4> <p> <a href="http://www.research.att.com/~bs/glossary.html#Gresource-acquisition-is-initialization" target="_top">RAII</a> - is absolutely perfect for the <code class="computeroutput"><span class="identifier">File</span></code> - class introduced above. Use of a properly designed <code class="computeroutput"><span class="identifier">File</span></code> + is absolutely perfect for the <code class="computeroutput"><span class="identifier">file</span></code> + class introduced above. Use of a properly designed <code class="computeroutput"><span class="identifier">file</span></code> class would look like: </p> <pre class="programlisting"><span class="keyword">try</span> <span class="special">{</span> - <span class="identifier">File</span> <span class="identifier">passwd</span><span class="special">(</span><span class="string">"/etc/passwd"</span><span class="special">);</span> - <span class="comment">// ... -</span><span class="special">}</span> -<span class="keyword">catch</span><span class="special">(...)</span> <span class="special">{</span> - <span class="identifier">log</span><span class="special">(</span><span class="string">"could not get user info"</span><span class="special">);</span> + <span class="identifier">file</span> <span class="identifier">passwd</span><span class="special">(</span><span class="string">"/etc/passwd"</span><span class="special">);</span> + <span class="comment">// ...</span> +<span class="special">}</span> <span class="keyword">catch</span><span class="special">(...)</span> <span class="special">{</span> + <span class="identifier">std</span><span class="special">::</span><span class="identifier">clog</span> <span class="special"><<</span> <span class="string">"could not get user info"</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span> <span class="keyword">throw</span><span class="special">;</span> <span class="special">}</span> </pre> @@ -108,20 +117,19 @@ guarantee</a> could introduce a lot of non-reusable <a href="http://www.research.att.com/~bs/glossary.html#Gresource-acquisition-is-initialization" target="_top">RAII</a> types. For example: </p> -<pre class="programlisting"><span class="identifier">m_persons</span><span class="special">.</span><span class="identifier">push_back</span><span class="special">(</span><span class="identifier">person</span><span class="special">);</span> -<span class="identifier">pop_back_if_not_commit</span> <span class="identifier">pop_back_if_not_commit_guard</span><span class="special">(</span><span class="identifier">commit</span><span class="special">,</span> <span class="identifier">m_persons</span><span class="special">);</span> +<pre class="programlisting"><span class="identifier">persons_</span><span class="special">.</span><span class="identifier">push_back</span><span class="special">(</span><span class="identifier">a_person</span><span class="special">);</span> +<span class="identifier">pop_back_if_not_commit</span> <span class="identifier">pop_back_if_not_commit_guard</span><span class="special">(</span><span class="identifier">commit</span><span class="special">,</span> <span class="identifier">persons_</span><span class="special">);</span> </pre> <p> The <code class="computeroutput"><span class="identifier">pop_back_if_not_commit</span></code> class is either defined out of the scope or as a local class: </p> <pre class="programlisting"><span class="keyword">class</span> <span class="identifier">pop_back_if_not_commit</span> <span class="special">{</span> - <span class="keyword">bool</span> <span class="identifier">m_commit</span><span class="special">;</span> - <span class="identifier">std</span><span class="special">::</span><span class="identifier">vector</span><span class="special"><</span><span class="identifier">Person</span><span class="special">>&</span> <span class="identifier">m_vec</span><span class="special">;</span> - <span class="comment">// ... -</span> <span class="special">~</span><span class="identifier">pop_back_if_not_commit</span><span class="special">()</span> <span class="special">{</span> - <span class="keyword">if</span><span class="special">(!</span><span class="identifier">m_commit</span><span class="special">)</span> - <span class="identifier">m_vec</span><span class="special">.</span><span class="identifier">pop_back</span><span class="special">();</span> + <span class="keyword">bool</span> <span class="identifier">commit_</span><span class="special">;</span> + <span class="identifier">std</span><span class="special">::</span><span class="identifier">vector</span><span class="special"><</span><span class="identifier">person</span><span class="special">>&</span> <span class="identifier">vec_</span><span class="special">;</span> + <span class="comment">// ...</span> + <span class="special">~</span><span class="identifier">pop_back_if_not_commit</span><span class="special">()</span> <span class="special">{</span> + <span class="keyword">if</span><span class="special">(!</span><span class="identifier">commit_</span><span class="special">)</span> <span class="identifier">vec_</span><span class="special">.</span><span class="identifier">pop_back</span><span class="special">();</span> <span class="special">}</span> <span class="special">};</span> </pre> @@ -129,34 +137,39 @@ In some cases <a href="http://www.research.att.com/~bs/glossary.html#Gstrong-guarantee" target="_top">strong guarantee</a> can be accomplished with standard utilities: </p> -<pre class="programlisting"><span class="identifier">std</span><span class="special">::</span><span class="identifier">auto_ptr</span><span class="special"><</span><span class="identifier">Person</span><span class="special">></span> <span class="identifier">spSuperMan</span><span class="special">(</span><span class="keyword">new</span> <span class="identifier">Superman</span><span class="special">);</span> -<span class="identifier">m_persons</span><span class="special">.</span><span class="identifier">push_back</span><span class="special">(</span><span class="identifier">spSuperMan</span><span class="special">.</span><span class="identifier">get</span><span class="special">());</span> -<span class="identifier">spSuperMan</span><span class="special">.</span><span class="identifier">release</span><span class="special">();</span> <span class="comment">// m_persons successfully took ownership. -</span></pre> +<pre class="programlisting"><span class="identifier">std</span><span class="special">::</span><span class="identifier">auto_ptr</span><span class="special"><</span><span class="identifier">Person</span><span class="special">></span> <span class="identifier">superman_ptr</span><span class="special">(</span><span class="keyword">new</span> <span class="identifier">superman</span><span class="special">());</span> +<span class="identifier">persons_</span><span class="special">.</span><span class="identifier">push_back</span><span class="special">(</span><span class="identifier">superman_ptr</span><span class="special">.</span><span class="identifier">get</span><span class="special">());</span> +<span class="identifier">superman_ptr</span><span class="special">.</span><span class="identifier">release</span><span class="special">();</span> <span class="comment">// persons_ successfully took ownership</span> +</pre> <p> - or with specialized containers such as <a href="../../../../../libs/ptr_container/doc/ptr_container.html" target="_top">Boost - Pointer Container Library</a> or <a href="../../../../../libs/multi_index/doc/index.html" target="_top">Boost - Multi-Index Containers Library</a>. + Or with specialized containers such as <a href="http://www.boost.org/libs/ptr_container" target="_top">Boost.PointerContainer</a> + or <a href="http://www.boost.org/libs/multi_index" target="_top">Boost.Multi-Index</a>. </p> -<a name="alternatives._ulink_url__http___www_ddj_com_dept_cpp_184403758__scopeguard__ulink_"></a><h4> -<a name="id761994"></a> - <a href="http://www.ddj.com/dept/cpp/184403758" target="_top">ScopeGuard</a> +<h4> +<a name="scope_exit.alternatives.h2"></a> + <span><a name="scope_exit.alternatives.scope_guards"></a></span><a class="link" href="alternatives.html#scope_exit.alternatives.scope_guards">Scope + Guards</a> </h4> <p> - Imagine that you add a new currency rate: + Imagine that a new currency rate is introduced before performing a transaction + (see also []): </p> +<p> +</p> <pre class="programlisting"><span class="keyword">bool</span> <span class="identifier">commit</span> <span class="special">=</span> <span class="keyword">false</span><span class="special">;</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span> <span class="identifier">currency</span><span class="special">(</span><span class="string">"EUR"</span><span class="special">);</span> <span class="keyword">double</span> <span class="identifier">rate</span> <span class="special">=</span> <span class="number">1.3326</span><span class="special">;</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">map</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="keyword">double</span><span class="special">></span> <span class="identifier">rates</span><span class="special">;</span> <span class="keyword">bool</span> <span class="identifier">currency_rate_inserted</span> <span class="special">=</span> - <span class="identifier">rates</span><span class="special">.</span><span class="identifier">insert</span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">make_pair</span><span class="special">(</span><span class="identifier">currency</span><span class="special">,</span> <span class="identifier">rate</span><span class="special">)).</span><span class="identifier">second</span><span class="special">;</span> + <span class="identifier">rates</span><span class="special">.</span><span class="identifier">insert</span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">make_pair</span><span class="special">(</span><span class="identifier">currency</span><span class="special">,</span> <span class="identifier">rate</span><span class="special">)).</span><span class="identifier">second</span><span class="special">;</span> +<span class="comment">// Transaction...</span> </pre> <p> - and then continue a transaction. If it cannot be completed, you erase the currency - from <code class="computeroutput"><span class="identifier">rates</span></code>. This is how you - can do this with <a href="http://www.ddj.com/dept/cpp/184403758" target="_top">ScopeGuard</a> - and <a href="../../../../../libs/lambda/index.html" target="_top">Boost.Lambda</a>: + </p> +<p> + If the transaction does not complete, the currency must be erased from <code class="computeroutput"><span class="identifier">rates</span></code>. This can be done with <a href="http://www.ddj.com/dept/cpp/184403758" target="_top">ScopeGuard</a> + and <a href="http://www.boost.org/libs/lambda" target="_top">Boost.Lambda</a> (or + <a href="http://www.boost.org/libs/phoenix" target="_top">Boost.Phoenix</a>): </p> <pre class="programlisting"><span class="keyword">using</span> <span class="keyword">namespace</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">lambda</span><span class="special">;</span> @@ -164,140 +177,142 @@ <span class="identifier">if_</span><span class="special">(</span><span class="identifier">currency_rate_inserted</span> <span class="special">&&</span> <span class="special">!</span><span class="identifier">_1</span><span class="special">)</span> <span class="special">[</span> <span class="identifier">bind</span><span class="special">(</span> <span class="keyword">static_cast</span><span class="special"><</span> - <span class="identifier">std</span><span class="special">::</span><span class="identifier">map</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="keyword">double</span><span class="special">>::</span><span class="identifier">size_type</span> <span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">map</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="keyword">double</span><span class="special">>::*)(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span> <span class="keyword">const</span><span class="special">&)</span> - <span class="special">>(&</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">map</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="keyword">double</span><span class="special">>::</span><span class="identifier">erase</span><span class="special">)</span> + <span class="identifier">std</span><span class="special">::</span><span class="identifier">map</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="keyword">double</span><span class="special">>::</span><span class="identifier">size_type</span> + <span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">map</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="keyword">double</span><span class="special">>::*)(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span> <span class="keyword">const</span><span class="special">&)</span> + <span class="special">>(&</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">map</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="keyword">double</span><span class="special">>::</span><span class="identifier">erase</span><span class="special">)</span> <span class="special">,</span> <span class="special">&</span><span class="identifier">rates</span> <span class="special">,</span> <span class="identifier">currency</span> - <span class="special">)</span> + <span class="special">)</span> <span class="special">]</span> <span class="special">,</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">cref</span><span class="special">(</span><span class="identifier">commit</span><span class="special">)</span> <span class="special">);</span> -<span class="comment">// ... -</span> +<span class="comment">// ...</span> + <span class="identifier">commit</span> <span class="special">=</span> <span class="keyword">true</span><span class="special">;</span> </pre> <p> - Note that + Note the following issues with this approach: </p> -<div class="itemizedlist"><ul class="itemizedlist" type="disc"> +<div class="orderedlist"><ol class="orderedlist" type="1"> <li class="listitem"> - Boost.lambda expressions are hard to write correctly, for example, overloaded - function must be explicitly casted, as demonstrated in this example, + <a href="http://www.boost.org/libs/lambda" target="_top">Boost.Lambda</a> expressions + are hard to write correctly (e.g., overloaded functions must be explicitly + casted, as demonstrated in the example above). </li> <li class="listitem"> - condition in <code class="computeroutput"><span class="identifier">if_</span></code> expression - refers to <code class="computeroutput"><span class="identifier">commit</span></code> variable - indirectly through the <code class="computeroutput"><span class="identifier">_1</span></code> - placeholder, + The condition in the <code class="computeroutput"><span class="identifier">if_</span></code> + expression refers to <code class="computeroutput"><span class="identifier">commit</span></code> + variable indirectly through the <code class="computeroutput"><span class="identifier">_1</span></code> + placeholder reducing readability. </li> <li class="listitem"> - setting a breakpoint inside <code class="computeroutput"><span class="identifier">if_</span><span class="special">[</span> <span class="special">...</span> <span class="special">]</span></code> - requires in-depth knowledge of <a href="../../../../../libs/lambda/index.html" target="_top">Boost.Lambda</a> - and debugging techniques. + Setting a breakpoint inside <code class="computeroutput"><span class="identifier">if_</span><span class="special">[...]</span></code> requires in-depth knowledge of <a href="http://www.boost.org/libs/lambda" target="_top">Boost.Lambda</a> and debugging + techniques. </li> -</ul></div> +</ol></div> <p> - This code will look much better with native lambda expressions proposed for - C++0x: + This code will look much better with C++11 lambdas: </p> <pre class="programlisting"><span class="identifier">ON_BLOCK_EXIT</span><span class="special">(</span> - <span class="special">[</span><span class="identifier">currency_rate_inserted</span><span class="special">,</span> <span class="special">&</span><span class="identifier">commit</span><span class="special">,</span> <span class="special">&</span><span class="identifier">rates</span><span class="special">,</span> <span class="special">&</span><span class="identifier">currency</span><span class="special">]()</span> <span class="special">-></span> <span class="keyword">void</span> - <span class="special">{</span> - <span class="keyword">if</span><span class="special">(</span><span class="identifier">currency_rate_inserted</span> <span class="special">&&</span> <span class="special">!</span><span class="identifier">commit</span><span class="special">)</span> - <span class="identifier">rates</span><span class="special">.</span><span class="identifier">erase</span><span class="special">(</span><span class="identifier">currency</span><span class="special">);</span> + <span class="special">[</span><span class="identifier">currency_rate_inserted</span><span class="special">,</span> <span class="special">&</span><span class="identifier">commit</span><span class="special">,</span> <span class="special">&</span><span class="identifier">rates</span><span class="special">,</span> <span class="special">&</span><span class="identifier">currency</span><span class="special">]()</span> <span class="special">{</span> + <span class="keyword">if</span><span class="special">(</span><span class="identifier">currency_rate_inserted</span> <span class="special">&&</span> <span class="special">!</span><span class="identifier">commit</span><span class="special">)</span> <span class="identifier">rates</span><span class="special">.</span><span class="identifier">erase</span><span class="special">(</span><span class="identifier">currency</span><span class="special">);</span> <span class="special">}</span> <span class="special">);</span> + +<span class="comment">// ...</span> + +<span class="identifier">commit</span> <span class="special">=</span> <span class="keyword">true</span><span class="special">;</span> </pre> <p> - With <a class="link" href="../index.html" title="Chapter 1. Boost.ScopeExit">ScopeExit</a> you can simply do + With <a class="link" href="../index.html" title="Chapter 1. Boost.ScopeExit 1.1.0">Boost.ScopeExit</a> we can simply do the + following (see also <a href="../../../example/scope_guard.cpp" target="_top"><code class="literal">scope_guard.cpp</code></a>): </p> -<pre class="programlisting"><span class="identifier">BOOST_SCOPE_EXIT</span><span class="special">(</span> <span class="special">(</span><span class="identifier">currency_rate_inserted</span><span class="special">)(&</span><span class="identifier">commit</span><span class="special">)(&</span><span class="identifier">rates</span><span class="special">)(&</span><span class="identifier">currency</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">currency_rate_inserted</span> <span class="special">&&</span> <span class="special">!</span><span class="identifier">commit</span><span class="special">)</span> - <span class="identifier">rates</span><span class="special">.</span><span class="identifier">erase</span><span class="special">(</span><span class="identifier">currency</span><span class="special">);</span> +<p> +</p> +<pre class="programlisting"><span class="identifier">BOOST_SCOPE_EXIT</span><span class="special">(</span><span class="identifier">currency_rate_inserted</span><span class="special">,</span> <span class="special">&</span><span class="identifier">commit</span><span class="special">,</span> <span class="special">&</span><span class="identifier">rates</span><span class="special">,</span> <span class="special">&</span><span class="identifier">currency</span><span class="special">)</span> <span class="special">{</span> + <span class="keyword">if</span><span class="special">(</span><span class="identifier">currency_rate_inserted</span> <span class="special">&&</span> <span class="special">!</span><span class="identifier">commit</span><span class="special">)</span> <span class="identifier">rates</span><span class="special">.</span><span class="identifier">erase</span><span class="special">(</span><span class="identifier">currency</span><span class="special">);</span> <span class="special">}</span> <span class="identifier">BOOST_SCOPE_EXIT_END</span> -<span class="comment">// ... -</span> +<span class="comment">// ...</span> + <span class="identifier">commit</span> <span class="special">=</span> <span class="keyword">true</span><span class="special">;</span> </pre> -<a name="alternatives.c__0x"></a><h4> -<a name="id762994"></a> - C++0x - </h4> <p> - In future releases <a class="link" href="../index.html" title="Chapter 1. Boost.ScopeExit">ScopeExit</a> will take advantages - of C++0x features. </p> -<div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem"> - Passing capture list as <a href="../../../../../libs/preprocessor/index.html" target="_top">Boost.Preprocessor - sequence</a> will be replaced with a traditional macro invocation style: - </li></ul></div> -<pre class="programlisting"><span class="identifier">BOOST_SCOPE_EXIT</span><span class="special">(</span><span class="identifier">currency_rate_inserted</span><span class="special">,</span> <span class="special">&</span><span class="identifier">commit</span><span class="special">,</span> <span class="special">&</span><span class="identifier">rates</span><span class="special">,</span> <span class="special">&</span><span class="identifier">currency</span><span class="special">)</span> -<span class="special">{</span> - <span class="keyword">if</span><span class="special">(</span><span class="identifier">currency_rate_inserted</span> <span class="special">&&</span> <span class="special">!</span><span class="identifier">commit</span><span class="special">)</span> - <span class="identifier">rates</span><span class="special">.</span><span class="identifier">erase</span><span class="special">(</span><span class="identifier">currency</span><span class="special">);</span> -<span class="special">}</span> <span class="identifier">BOOST_SCOPE_EXIT_END</span> -</pre> -<div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem"> - <code class="computeroutput"><span class="identifier">BOOST_SCOPE_EXIT_END</span></code> will - be replaced with a semicolon: - </li></ul></div> -<pre class="programlisting"><span class="identifier">BOOST_SCOPE_EXIT</span><span class="special">(</span><span class="identifier">currency_rate_inserted</span><span class="special">,</span> <span class="special">&</span><span class="identifier">commit</span><span class="special">,</span> <span class="special">&</span><span class="identifier">rates</span><span class="special">,</span> <span class="special">&</span><span class="identifier">currency</span><span class="special">)</span> -<span class="special">{</span> - <span class="keyword">if</span><span class="special">(</span><span class="identifier">currency_rate_inserted</span> <span class="special">&&</span> <span class="special">!</span><span class="identifier">commit</span><span class="special">)</span> - <span class="identifier">rates</span><span class="special">.</span><span class="identifier">erase</span><span class="special">(</span><span class="identifier">currency</span><span class="special">);</span> -<span class="special">};</span> -</pre> -<div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem"> - Users will be able to capture local variables implicitly with lambda capture - defaults <code class="computeroutput"><span class="special">&</span></code> and <code class="computeroutput"><span class="special">=</span></code>: - </li></ul></div> -<pre class="programlisting"><span class="identifier">BOOST_SCOPE_EXIT</span><span class="special">(&,</span> <span class="identifier">currency_rate_inserted</span><span class="special">)</span> -<span class="special">{</span> - <span class="keyword">if</span><span class="special">(</span><span class="identifier">currency_rate_inserted</span> <span class="special">&&</span> <span class="special">!</span><span class="identifier">commit</span><span class="special">)</span> - <span class="identifier">rates</span><span class="special">.</span><span class="identifier">erase</span><span class="special">(</span><span class="identifier">currency</span><span class="special">);</span> -<span class="special">};</span> -</pre> -<div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem"> - It will be possible to capture <code class="computeroutput"><span class="keyword">this</span></code> - pointer. - </li></ul></div> -<a name="alternatives.the_d_programming_language"></a><h4> -<a name="id763445"></a> - The D Programming Language +<h4> +<a name="scope_exit.alternatives.h3"></a> + <span><a name="scope_exit.alternatives.the_d_programming_language"></a></span><a class="link" href="alternatives.html#scope_exit.alternatives.the_d_programming_language">The + D Programming Language</a> </h4> <p> - <span class="underline">ScopeExit</span> is similar to <a href="http://www.digitalmars.com/d/2.0/statement.html#ScopeGuardStatement" target="_top">scope(exit)</a> + <a class="link" href="../index.html" title="Chapter 1. Boost.ScopeExit 1.1.0">Boost.ScopeExit</a> is similar to <a href="http://www.digitalmars.com/d/2.0/statement.html#ScopeGuardStatement" target="_top">scope(exit)</a> feature built into the <a href="http://www.digitalmars.com/d/index.html" target="_top">D</a> programming language. </p> <p> - A curious reader may notice that the library doesn't implement <code class="computeroutput"><span class="identifier">scope</span><span class="special">(</span><span class="identifier">success</span><span class="special">)</span></code> and <code class="computeroutput"><span class="identifier">scope</span><span class="special">(</span><span class="identifier">failure</span><span class="special">)</span></code> of the <a href="http://www.digitalmars.com/d/index.html" target="_top">D</a> - language. Unfortunately, it's not possible in C++ because failure or success - condition cannot be determined by calling <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">uncaught_exception</span></code>. - It's not a big problem, though. These two constructs can be expressed in terms - of <a href="http://www.digitalmars.com/d/2.0/statement.html#ScopeGuardStatement" target="_top">scope(exit)</a> + A curious reader may notice that the library does not implement <code class="computeroutput"><span class="identifier">scope</span><span class="special">(</span><span class="identifier">success</span><span class="special">)</span></code> and <code class="computeroutput"><span class="identifier">scope</span><span class="special">(</span><span class="identifier">failure</span><span class="special">)</span></code> of the <a href="http://www.digitalmars.com/d/index.html" target="_top">D</a> + language. Unfortunately, these are not possible in C++ because failure or success + conditions cannot be determined by calling <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">uncaught_exception</span></code> + (see <a href="http://www.gotw.ca/gotw/047.htm" target="_top">Guru of the Week #47</a> + for details about <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">uncaught_exception</span></code> and if it has any good + use at all). However, this is not a big problem because these two <a href="http://www.digitalmars.com/d/index.html" target="_top">D</a>'s + constructs can be expressed in terms of <a href="http://www.digitalmars.com/d/2.0/statement.html#ScopeGuardStatement" target="_top">scope(exit)</a> and a <code class="computeroutput"><span class="keyword">bool</span> <span class="identifier">commit</span></code> - variable as explained in <a class="link" href="tutorial.html" title="Tutorial">Tutorial</a>. - Refer to <a href="http://www.gotw.ca/gotw/047.htm" target="_top">Guru of the Week #47</a> - for more details about <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">uncaught_exception</span></code> - and if it has any good use at all. + variable (similarly to some examples presented in the <a class="link" href="tutorial.html" title="Tutorial">Tutorial</a> + section). + </p> +<h4> +<a name="scope_exit.alternatives.h4"></a> + <span><a name="scope_exit.alternatives.c__11_lambdas"></a></span><a class="link" href="alternatives.html#scope_exit.alternatives.c__11_lambdas">C++11 + Lambdas</a> + </h4> +<p> + Using C++11 lambdas, it is relatively easy to implement the <a class="link" href="../index.html" title="Chapter 1. Boost.ScopeExit 1.1.0">Boost.ScopeExit</a> + construct. For example (see also <a href="../../../example/world_cxx11_lambda.cpp" target="_top"><code class="literal">world_cxx11_lambda.cpp</code></a>): + </p> +<p> +</p> +<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">functional</span><span class="special">></span> + +<span class="keyword">struct</span> <span class="identifier">scope_exit</span> <span class="special">{</span> + <span class="identifier">scope_exit</span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">function</span><span class="special"><</span><span class="keyword">void</span> <span class="special">(</span><span class="keyword">void</span><span class="special">)></span> <span class="identifier">f</span><span class="special">)</span> <span class="special">:</span> <span class="identifier">f_</span><span class="special">(</span><span class="identifier">f</span><span class="special">)</span> <span class="special">{}</span> + <span class="special">~</span><span class="identifier">scope_exit</span><span class="special">(</span><span class="keyword">void</span><span class="special">)</span> <span class="special">{</span> <span class="identifier">f_</span><span class="special">();</span> <span class="special">}</span> +<span class="keyword">private</span><span class="special">:</span> + <span class="identifier">std</span><span class="special">::</span><span class="identifier">function</span><span class="special"><</span><span class="keyword">void</span> <span class="special">(</span><span class="keyword">void</span><span class="special">)></span> <span class="identifier">f_</span><span class="special">;</span> +<span class="special">};</span> + +<span class="keyword">void</span> <span class="identifier">world</span><span class="special">::</span><span class="identifier">add_person</span><span class="special">(</span><span class="identifier">person</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">a_person</span><span class="special">)</span> <span class="special">{</span> + <span class="keyword">bool</span> <span class="identifier">commit</span> <span class="special">=</span> <span class="keyword">false</span><span class="special">;</span> + + <span class="identifier">persons_</span><span class="special">.</span><span class="identifier">push_back</span><span class="special">(</span><span class="identifier">a_person</span><span class="special">);</span> + <span class="identifier">scope_exit</span> <span class="identifier">on_exit1</span><span class="special">([&</span><span class="identifier">commit</span><span class="special">,</span> <span class="keyword">this</span><span class="special">](</span><span class="keyword">void</span><span class="special">)</span> <span class="special">{</span> <span class="comment">// Use C++11 lambda.</span> + <span class="keyword">if</span><span class="special">(!</span><span class="identifier">commit</span><span class="special">)</span> <span class="identifier">persons_</span><span class="special">.</span><span class="identifier">pop_back</span><span class="special">();</span> <span class="comment">// `persons_` via captured `this`.</span> + <span class="special">});</span> + + <span class="comment">// ...</span> + + <span class="identifier">commit</span> <span class="special">=</span> <span class="keyword">true</span><span class="special">;</span> +<span class="special">}</span> +</pre> +<p> + </p> +<p> + However, this library allows to program the <a class="link" href="../index.html" title="Chapter 1. Boost.ScopeExit 1.1.0">Boost.ScopeExit</a> + construct in a way that is portable between C++03 and C++11 compilers. </p> </div> <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> <td align="left"></td> -<td align="right"><div class="copyright-footer">Copyright © 2006 -2009 Alexander Nasonov<p> - Distributed under the Boost Software License, Version 1.0. (See accompanying - file LICENSE_1_0.txt or copy at <ulink url="http://www.boost.org/LICENSE_1_0.txt"> - http://www.boost.org/LICENSE_1_0.txt </ulink>) +<td align="right"><div class="copyright-footer">Copyright © 2006-2012 Alexander Nasonov, Lorenzo Caminiti<p> + Distributed under the Boost Software License, Version 1.0 (see accompanying + file LICENSE_1_0.txt or a copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>) </p> </div></td> </tr></table> <hr> <div class="spirit-nav"> -<a accesskey="p" href="tutorial.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="compilers.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a> +<a accesskey="p" href="tutorial.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="no_variadic_macros.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a> </div> </body> </html> diff --git a/libs/scope_exit/doc/html/scope_exit/compilers.html b/libs/scope_exit/doc/html/scope_exit/compilers.html deleted file mode 100644 index 39f8886980..0000000000 --- a/libs/scope_exit/doc/html/scope_exit/compilers.html +++ /dev/null @@ -1,61 +0,0 @@ -<html> -<head> -<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII"> -<title>Supported Compilers</title> -<link rel="stylesheet" href="../../../../../doc/src/boostbook.css" type="text/css"> -<meta name="generator" content="DocBook XSL Stylesheets V1.75.2"> -<link rel="home" href="../index.html" title="Chapter 1. Boost.ScopeExit"> -<link rel="up" href="../index.html" title="Chapter 1. Boost.ScopeExit"> -<link rel="prev" href="alternatives.html" title="Alternatives"> -<link rel="next" href="conf.html" title="Configuration"> -</head> -<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> -<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="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="alternatives.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="conf.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a> -</div> -<div class="section"> -<div class="titlepage"><div><div><h2 class="title" style="clear: both"> -<a name="scope_exit.compilers"></a> Supported Compilers</h2></div></div></div> -<p> - The library should be usable on any compiler that supports <a href="../../../../../libs/typeof/index.html" target="_top">Boost.Typeof</a> - except - </p> -<div class="itemizedlist"><ul class="itemizedlist" type="disc"> -<li class="listitem"> - MSVC 7.1 and 8.0 fail to link if a function with <a class="link" href="../index.html" title="Chapter 1. Boost.ScopeExit">ScopeExit</a> - is included by multiple translation units. - </li> -<li class="listitem"> - GCC 3.3 can't compile <a class="link" href="../index.html" title="Chapter 1. Boost.ScopeExit">ScopeExit</a> inside - a template. See <a href="http://lists.boost.org/Archives/boost/2007/02/116235.php" target="_top">this - thread</a> for more details. - </li> -</ul></div> -<p> - The author tested the library on GCC 3.3, 3.4, 4.1, 4.2 and Intel 10.1. - </p> -</div> -<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> -<td align="left"></td> -<td align="right"><div class="copyright-footer">Copyright © 2006 -2009 Alexander Nasonov<p> - Distributed under the Boost Software License, Version 1.0. (See accompanying - file LICENSE_1_0.txt or copy at <ulink url="http://www.boost.org/LICENSE_1_0.txt"> - http://www.boost.org/LICENSE_1_0.txt </ulink>) - </p> -</div></td> -</tr></table> -<hr> -<div class="spirit-nav"> -<a accesskey="p" href="alternatives.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="conf.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a> -</div> -</body> -</html> diff --git a/libs/scope_exit/doc/html/scope_exit/conf.html b/libs/scope_exit/doc/html/scope_exit/conf.html deleted file mode 100644 index a3b504d5a1..0000000000 --- a/libs/scope_exit/doc/html/scope_exit/conf.html +++ /dev/null @@ -1,49 +0,0 @@ -<html> -<head> -<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII"> -<title>Configuration</title> -<link rel="stylesheet" href="../../../../../doc/src/boostbook.css" type="text/css"> -<meta name="generator" content="DocBook XSL Stylesheets V1.75.2"> -<link rel="home" href="../index.html" title="Chapter 1. Boost.ScopeExit"> -<link rel="up" href="../index.html" title="Chapter 1. Boost.ScopeExit"> -<link rel="prev" href="compilers.html" title="Supported Compilers"> -<link rel="next" href="ref.html" title="Reference"> -</head> -<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> -<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="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="compilers.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="ref.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a> -</div> -<div class="section"> -<div class="titlepage"><div><div><h2 class="title" style="clear: both"> -<a name="scope_exit.conf"></a> Configuration</h2></div></div></div> -<p> - Normally, no configuration is required for the library but note that the library - depends on <a href="../../../../../libs/typeof/index.html" target="_top">Boost.Typeof</a> - and you may want to configure or enforce <a href="../../../../../libs/typeof/index.html" target="_top">typeof - emulation</a>. - </p> -</div> -<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> -<td align="left"></td> -<td align="right"><div class="copyright-footer">Copyright © 2006 -2009 Alexander Nasonov<p> - Distributed under the Boost Software License, Version 1.0. (See accompanying - file LICENSE_1_0.txt or copy at <ulink url="http://www.boost.org/LICENSE_1_0.txt"> - http://www.boost.org/LICENSE_1_0.txt </ulink>) - </p> -</div></td> -</tr></table> -<hr> -<div class="spirit-nav"> -<a accesskey="p" href="compilers.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="ref.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a> -</div> -</body> -</html> diff --git a/libs/scope_exit/doc/html/scope_exit/getting_started.html b/libs/scope_exit/doc/html/scope_exit/getting_started.html new file mode 100644 index 0000000000..7a51381d8c --- /dev/null +++ b/libs/scope_exit/doc/html/scope_exit/getting_started.html @@ -0,0 +1,138 @@ +<html> +<head> +<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII"> +<title>Getting Started</title> +<link rel="stylesheet" href="../../../../../doc/src/boostbook.css" type="text/css"> +<meta name="generator" content="DocBook XSL Stylesheets V1.76.1"> +<link rel="home" href="../index.html" title="Chapter 1. Boost.ScopeExit 1.1.0"> +<link rel="up" href="../index.html" title="Chapter 1. Boost.ScopeExit 1.1.0"> +<link rel="prev" href="../index.html" title="Chapter 1. Boost.ScopeExit 1.1.0"> +<link rel="next" href="tutorial.html" title="Tutorial"> +</head> +<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> +<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="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="../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="tutorial.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a> +</div> +<div class="section scope_exit_getting_started"> +<div class="titlepage"><div><div><h2 class="title" style="clear: both"> +<a name="scope_exit.getting_started"></a><a class="link" href="getting_started.html" title="Getting Started">Getting Started</a> +</h2></div></div></div> +<div class="toc"><dl> +<dt><span class="section"><a href="getting_started.html#scope_exit.getting_started.this_documentation">This Documentation</a></span></dt> +<dt><span class="section"><a href="getting_started.html#scope_exit.getting_started.compilers_and_platforms">Compilers + and Platforms</a></span></dt> +<dt><span class="section"><a href="getting_started.html#scope_exit.getting_started.installation">Installation</a></span></dt> +</dl></div> +<p> + This section explains how to setup a system to use this library. + </p> +<div class="section scope_exit_getting_started_this_documentation"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="scope_exit.getting_started.this_documentation"></a><a class="link" href="getting_started.html#scope_exit.getting_started.this_documentation" title="This Documentation">This Documentation</a> +</h3></div></div></div> +<p> + Programmers should have enough knowledge to use this library after reading + the <a class="link" href="../index.html#scope_exit.introduction" title="Introduction">Introduction</a>, <a class="link" href="getting_started.html" title="Getting Started">Getting + Started</a>, and <a class="link" href="tutorial.html" title="Tutorial">Tutorial</a> sections. + The <a href="../reference.html" target="_top">Reference</a> section can be consulted + at a later point for quick reference. All the other sections of this documentation + can be considered optional. + </p> +<p> + Some footnotes are marked by the word "<span class="bold"><strong>Rationale</strong></span>". + They explain reasons behind decisions made during the design and implementation + of this library. + </p> +<p> + In most of the examples presented in this documentation, the Boost.Detail/LightweightTest + (<code class="literal">boost/detail/lightweight_test.hpp</code>) macro <code class="computeroutput"><span class="identifier">BOOST_TEST</span></code> is used to check correctness + conditions. The <code class="computeroutput"><span class="identifier">BOOST_TEST</span></code> + macro is conceptually similar to <code class="computeroutput"><span class="identifier">assert</span></code> + but a failure of the checked condition does not abort the program, instead + it makes <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">report_errors</span></code> return a non-zero program + exit code. <sup>[<a name="scope_exit.getting_started.this_documentation.f0" href="#ftn.scope_exit.getting_started.this_documentation.f0" class="footnote">2</a>]</sup> + </p> +</div> +<div class="section scope_exit_getting_started_compilers_and_platforms"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="scope_exit.getting_started.compilers_and_platforms"></a><a class="link" href="getting_started.html#scope_exit.getting_started.compilers_and_platforms" title="Compilers and Platforms">Compilers + and Platforms</a> +</h3></div></div></div> +<p> + The authors originally developed and tested the library on GNU Compiler Collection + (GCC) C++ 3.3, 3.4, 4.1, 4.2, 4.5.3 (with and without C++11 features <code class="literal">-std=c++0x</code>), + Microsoft Visual C++ (MSVC) 8.0, and Intel 10.1 under Linux, Cygwin, and + Windows 7. However, this library should be usable on any compiler that supports + <a href="http://www.boost.org/libs/typeof" target="_top">Boost.Typeof</a> except: + </p> +<div class="itemizedlist"><ul class="itemizedlist" type="disc"> +<li class="listitem"> + MSVC 7.1 and 8.0 fail to link if a function with <a class="link" href="../index.html" title="Chapter 1. Boost.ScopeExit 1.1.0">Boost.ScopeExit</a> + is included by multiple translation units. + </li> +<li class="listitem"> + GCC 3.3 cannot compile <a class="link" href="../index.html" title="Chapter 1. Boost.ScopeExit 1.1.0">Boost.ScopeExit</a> + inside a template (see <a href="http://lists.boost.org/Archives/boost/2007/02/116235.php" target="_top">http://lists.boost.org/Archives/boost/2007/02/116235.php</a> + for details). + </li> +</ul></div> +<p> + See the library <a href="http://www.boost.org/development/tests/release/developer/scope_exit.html" target="_top">regression + test results</a> for detailed information on supported compilers and + platforms. Check the library regression test <a href="../../../test/Jamfile.v2" target="_top"><code class="literal">Jamfile.v2</code></a> + for any special configuration that might be required for a specific compiler. + </p> +</div> +<div class="section scope_exit_getting_started_installation"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="scope_exit.getting_started.installation"></a><a class="link" href="getting_started.html#scope_exit.getting_started.installation" title="Installation">Installation</a> +</h3></div></div></div> +<p> + This library is composed of header files only. Therefore there is no pre-compiled + object file which needs to be installed. Programmers can simply instruct + the compiler where to find the library header files (<code class="computeroutput"><span class="special">-</span><span class="identifier">I</span></code> option on GCC, <code class="computeroutput"><span class="special">/</span><span class="identifier">I</span></code> option on MSVC, etc) and compile code + using the library. + </p> +<p> + The library implementation uses <a href="http://www.boost.org/libs/typeof" target="_top">Boost.Typeof</a> + to automatically deduce the types of the <a class="link" href="../index.html" title="Chapter 1. Boost.ScopeExit 1.1.0">Boost.ScopeExit</a> + captured variables (see the <a class="link" href="tutorial.html" title="Tutorial">Tutorial</a> + section). In order to compile code in <a href="http://www.boost.org/libs/typeof" target="_top">type-of + emulation</a> mode, all types should be properly registered using <code class="computeroutput"><span class="identifier">BOOST_TYPEOF_REGISTER_TYPE</span></code> and <code class="computeroutput"><span class="identifier">BOOST_TYPEOF_REGISTER_TEMPLATE</span></code>, or appropriate + <a href="http://www.boost.org/libs/typeof" target="_top">Boost.Typeof</a> headers + should be included (see the source code of most examples presented in this + documentation). + </p> +</div> +<div class="footnotes"> +<br><hr width="100" align="left"> +<div class="footnote"><p><sup>[<a id="ftn.scope_exit.getting_started.this_documentation.f0" href="#scope_exit.getting_started.this_documentation.f0" class="para">2</a>] </sup> + <span class="bold"><strong>Rationale.</strong></span> Using Boost.Detail/LightweightTest + allows to add the examples to the library regression tests so to make sure + that they always compile and run correctly. + </p></div> +</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 © 2006-2012 Alexander Nasonov, Lorenzo Caminiti<p> + Distributed under the Boost Software License, Version 1.0 (see accompanying + file LICENSE_1_0.txt or a copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>) + </p> +</div></td> +</tr></table> +<hr> +<div class="spirit-nav"> +<a accesskey="p" href="../index.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.html"><img src="../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="tutorial.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a> +</div> +</body> +</html> diff --git a/libs/scope_exit/doc/html/scope_exit/no_variadic_macros.html b/libs/scope_exit/doc/html/scope_exit/no_variadic_macros.html new file mode 100644 index 0000000000..cf28f1e811 --- /dev/null +++ b/libs/scope_exit/doc/html/scope_exit/no_variadic_macros.html @@ -0,0 +1,229 @@ +<html> +<head> +<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII"> +<title>Annex: No Variadic Macros</title> +<link rel="stylesheet" href="../../../../../doc/src/boostbook.css" type="text/css"> +<meta name="generator" content="DocBook XSL Stylesheets V1.76.1"> +<link rel="home" href="../index.html" title="Chapter 1. Boost.ScopeExit 1.1.0"> +<link rel="up" href="../index.html" title="Chapter 1. Boost.ScopeExit 1.1.0"> +<link rel="prev" href="alternatives.html" title="Annex: Alternatives"> +<link rel="next" href="../reference.html" title="Reference"> +</head> +<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> +<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="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="alternatives.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="../reference.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a> +</div> +<div class="section scope_exit_no_variadic_macros"> +<div class="titlepage"><div><div><h2 class="title" style="clear: both"> +<a name="scope_exit.no_variadic_macros"></a><a class="link" href="no_variadic_macros.html" title="Annex: No Variadic Macros">Annex: No Variadic Macros</a> +</h2></div></div></div> +<p> + This section presents an alternative syntax for compilers without variadic + macro support. + </p> +<h4> +<a name="scope_exit.no_variadic_macros.h0"></a> + <span><a name="scope_exit.no_variadic_macros.sequence_syntax"></a></span><a class="link" href="no_variadic_macros.html#scope_exit.no_variadic_macros.sequence_syntax">Sequence + Syntax</a> + </h4> +<p> + Most modern compilers support variadic macros (notably, these include GCC, + MSVC, and all C++11 compilers). <sup>[<a name="scope_exit.no_variadic_macros.f0" href="#ftn.scope_exit.no_variadic_macros.f0" class="footnote">10</a>]</sup> However, in the rare case that programmers need to use this library + on a complier without variaidc macros, this library also allows to specify + the capture list using a <a href="http://www.boost.org/libs/preprocessor" target="_top">Boost.Preprocessor</a> + sequence where tokens are separated by round parenthesis <code class="computeroutput"><span class="special">()</span></code>: + </p> +<pre class="programlisting"><span class="special">(</span><span class="identifier">capture1</span><span class="special">)</span> <span class="special">(</span><span class="identifier">capture2</span><span class="special">)</span> <span class="special">...</span> <span class="comment">// All compilers.</span> +</pre> +<p> + Instead of the comma-separated list that we have seen so far which requires + variadic macros: + </p> +<pre class="programlisting"><span class="identifier">capture1</span><span class="special">,</span> <span class="identifier">capture2</span><span class="special">,</span> <span class="special">...</span> <span class="comment">// Only compilers with variadic macros.</span> +</pre> +<p> + For example, the following syntax is accepted on all compilers with and without + variadic macros (see also <a href="../../../test/world_seq.cpp" target="_top"><code class="literal">world_seq.cpp</code></a> + and <a href="../../../test/world.cpp" target="_top"><code class="literal">world.cpp</code></a>): + </p> +<div class="informaltable"><table class="table"> +<colgroup> +<col> +<col> +</colgroup> +<thead><tr> +<th> + <p> + Boost.Preprocessor Sequence (All Compilers) + </p> + </th> +<th> + <p> + Comma-Separated List (Variadic Macros Only) + </p> + </th> +</tr></thead> +<tbody><tr> +<td> + <p> +</p> +<pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"><span class="keyword">void</span> <span class="identifier">world</span><span class="special">::</span><span class="identifier">add_person</span><span class="special">(</span><span class="identifier">person</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">a_person</span><span class="special">)</span> <span class="special">{</span> + <span class="keyword">bool</span> <span class="identifier">commit</span> <span class="special">=</span> <span class="keyword">false</span><span class="special">;</span> + + <span class="identifier">persons_</span><span class="special">.</span><span class="identifier">push_back</span><span class="special">(</span><span class="identifier">a_person</span><span class="special">);</span> <span class="comment">// (1) direct action</span> + <span class="comment">// Following block is executed when the enclosing scope exits.</span> + <span class="identifier">BOOST_SCOPE_EXIT</span><span class="special">(</span> <span class="special">(&</span><span class="identifier">commit</span><span class="special">)</span> <span class="special">(&</span><span class="identifier">persons_</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">commit</span><span class="special">)</span> <span class="identifier">persons_</span><span class="special">.</span><span class="identifier">pop_back</span><span class="special">();</span> <span class="comment">// (2) rollback action</span> + <span class="special">}</span> <span class="identifier">BOOST_SCOPE_EXIT_END</span> + + <span class="comment">// ... // (3) other operations</span> + + <span class="identifier">commit</span> <span class="special">=</span> <span class="keyword">true</span><span class="special">;</span> <span class="comment">// (4) disable rollback actions</span> +<span class="special">}</span> +</pre> +<p> + </p> + </td> +<td> + <p> +</p> +<pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"><span class="keyword">void</span> <span class="identifier">world</span><span class="special">::</span><span class="identifier">add_person</span><span class="special">(</span><span class="identifier">person</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">a_person</span><span class="special">)</span> <span class="special">{</span> + <span class="keyword">bool</span> <span class="identifier">commit</span> <span class="special">=</span> <span class="keyword">false</span><span class="special">;</span> + + <span class="identifier">persons_</span><span class="special">.</span><span class="identifier">push_back</span><span class="special">(</span><span class="identifier">a_person</span><span class="special">);</span> <span class="comment">// (1) direct action</span> + <span class="comment">// Following block is executed when the enclosing scope exits.</span> + <span class="identifier">BOOST_SCOPE_EXIT</span><span class="special">(&</span><span class="identifier">commit</span><span class="special">,</span> <span class="special">&</span><span class="identifier">persons_</span><span class="special">)</span> <span class="special">{</span> + <span class="keyword">if</span><span class="special">(!</span><span class="identifier">commit</span><span class="special">)</span> <span class="identifier">persons_</span><span class="special">.</span><span class="identifier">pop_back</span><span class="special">();</span> <span class="comment">// (2) rollback action</span> + <span class="special">}</span> <span class="identifier">BOOST_SCOPE_EXIT_END</span> + + <span class="comment">// ... // (3) other operations</span> + + <span class="identifier">commit</span> <span class="special">=</span> <span class="keyword">true</span><span class="special">;</span> <span class="comment">// (4) disable rollback actions</span> +<span class="special">}</span> +</pre> +<p> + </p> + </td> +</tr></tbody> +</table></div> +<p> + Note how the same macros accept both syntaxes on compilers with variadic macros + and only the <a href="http://www.boost.org/libs/preprocessor" target="_top">Boost.Preprocessor</a> + sequence syntax on compilers without variadic macros. Older versions of this + library used to only support the <a href="http://www.boost.org/libs/preprocessor" target="_top">Boost.Preprocessor</a> + sequence syntax so this syntax is supported also for backward compatibility. + However, in the current version of this library and on compilers with variadic + macros, the comma-separated syntax is preferred because it is more readable. + </p> +<p> + Finally, an empty capture list is always specified using <code class="computeroutput"><span class="keyword">void</span></code> + on compilers with and without variaidc macros (see also <a href="../../../test/world_void.cpp" target="_top"><code class="literal">world_void.cpp</code></a>): + </p> +<p> +</p> +<pre class="programlisting"><span class="keyword">struct</span> <span class="identifier">world_t</span> <span class="special">{</span> + <span class="identifier">std</span><span class="special">::</span><span class="identifier">vector</span><span class="special"><</span><span class="identifier">person</span><span class="special">></span> <span class="identifier">persons</span><span class="special">;</span> + <span class="keyword">bool</span> <span class="identifier">commit</span><span class="special">;</span> +<span class="special">}</span> <span class="identifier">world</span><span class="special">;</span> <span class="comment">// Global variable.</span> + +<span class="keyword">void</span> <span class="identifier">add_person</span><span class="special">(</span><span class="identifier">person</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">a_person</span><span class="special">)</span> <span class="special">{</span> + <span class="identifier">world</span><span class="special">.</span><span class="identifier">commit</span> <span class="special">=</span> <span class="keyword">false</span><span class="special">;</span> + <span class="identifier">world</span><span class="special">.</span><span class="identifier">persons</span><span class="special">.</span><span class="identifier">push_back</span><span class="special">(</span><span class="identifier">a_person</span><span class="special">);</span> + + <span class="identifier">BOOST_SCOPE_EXIT</span><span class="special">(</span><span class="keyword">void</span><span class="special">)</span> <span class="special">{</span> <span class="comment">// No captures.</span> + <span class="keyword">if</span><span class="special">(!</span><span class="identifier">world</span><span class="special">.</span><span class="identifier">commit</span><span class="special">)</span> <span class="identifier">world</span><span class="special">.</span><span class="identifier">persons</span><span class="special">.</span><span class="identifier">pop_back</span><span class="special">();</span> + <span class="special">}</span> <span class="identifier">BOOST_SCOPE_EXIT_END</span> + + <span class="comment">// ...</span> + + <span class="identifier">world</span><span class="special">.</span><span class="identifier">commit</span> <span class="special">=</span> <span class="keyword">true</span><span class="special">;</span> +<span class="special">}</span> +</pre> +<p> + </p> +<h4> +<a name="scope_exit.no_variadic_macros.h1"></a> + <span><a name="scope_exit.no_variadic_macros.examples"></a></span><a class="link" href="no_variadic_macros.html#scope_exit.no_variadic_macros.examples">Examples</a> + </h4> +<p> + For reference, the following is a list of most of the examples presented in + this documentation reprogrammed using the <a href="http://www.boost.org/libs/preprocessor" target="_top">Boost.Preprocessor</a> + sequence syntax instead of comma-separated lists (in alphabetic order): + </p> +<div class="informaltable"><table class="table"> +<colgroup><col></colgroup> +<thead><tr><th> + <p> + Files + </p> + </th></tr></thead> +<tbody> +<tr><td> + <p> + <a href="../../../test/same_line_seq.cpp" target="_top"><code class="literal">same_line_seq.cpp</code></a> + </p> + </td></tr> +<tr><td> + <p> + <a href="../../../example/scope_guard_seq.cpp" target="_top"><code class="literal">scope_guard_seq.cpp</code></a> + </p> + </td></tr> +<tr><td> + <p> + <a href="../../../example/try_catch_seq.cpp" target="_top"><code class="literal">try_catch_seq.cpp</code></a> + </p> + </td></tr> +<tr><td> + <p> + <a href="../../../test/world_checkpoint_all_seq.cpp" target="_top"><code class="literal">world_checkpoint_all_seq.cpp</code></a> + </p> + </td></tr> +<tr><td> + <p> + <a href="../../../test/world_checkpoint_seq.cpp" target="_top"><code class="literal">world_checkpoint_seq.cpp</code></a> + </p> + </td></tr> +<tr><td> + <p> + <a href="../../../test/world_this_seq.cpp" target="_top"><code class="literal">world_this_seq.cpp</code></a> + </p> + </td></tr> +<tr><td> + <p> + <a href="../../../test/world_tpl_seq.cpp" target="_top"><code class="literal">world_tpl_seq.cpp</code></a> + </p> + </td></tr> +</tbody> +</table></div> +<div class="footnotes"> +<br><hr width="100" align="left"> +<div class="footnote"><p><sup>[<a id="ftn.scope_exit.no_variadic_macros.f0" href="#scope_exit.no_variadic_macros.f0" class="para">10</a>] </sup> + A C++ compiler does not support variadic macros if the <a href="http://www.boost.org/libs/config" target="_top">Boost.Config</a> + macro <code class="computeroutput"><span class="identifier">BOOST_NO_VARIADIC_MACROS</span></code> + is defined for that compiler. + </p></div> +</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 © 2006-2012 Alexander Nasonov, Lorenzo Caminiti<p> + Distributed under the Boost Software License, Version 1.0 (see accompanying + file LICENSE_1_0.txt or a copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>) + </p> +</div></td> +</tr></table> +<hr> +<div class="spirit-nav"> +<a accesskey="p" href="alternatives.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="../reference.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a> +</div> +</body> +</html> diff --git a/libs/scope_exit/doc/html/scope_exit/ref.html b/libs/scope_exit/doc/html/scope_exit/ref.html deleted file mode 100644 index ef783c01e9..0000000000 --- a/libs/scope_exit/doc/html/scope_exit/ref.html +++ /dev/null @@ -1,153 +0,0 @@ -<html> -<head> -<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII"> -<title>Reference</title> -<link rel="stylesheet" href="../../../../../doc/src/boostbook.css" type="text/css"> -<meta name="generator" content="DocBook XSL Stylesheets V1.75.2"> -<link rel="home" href="../index.html" title="Chapter 1. Boost.ScopeExit"> -<link rel="up" href="../index.html" title="Chapter 1. Boost.ScopeExit"> -<link rel="prev" href="conf.html" title="Configuration"> -<link rel="next" href="acknowledge.html" title="Acknowledge"> -</head> -<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> -<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="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="conf.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="acknowledge.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a> -</div> -<div class="section"> -<div class="titlepage"><div><div><h2 class="title" style="clear: both"> -<a name="scope_exit.ref"></a> Reference</h2></div></div></div> -<a name="ref.boost_scope_exit"></a><h4> -<a name="id763687"></a> - BOOST_SCOPE_EXIT - </h4> -<p> - A <a class="link" href="../index.html" title="Chapter 1. Boost.ScopeExit">ScopeExit</a> declaration has the following - synopsis: - </p> -<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">scope_exit</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> - -<span class="identifier">BOOST_SCOPE_EXIT</span> <span class="special">(</span> <span class="identifier">scope</span><span class="special">-</span><span class="identifier">exit</span><span class="special">-</span><span class="identifier">capture</span><span class="special">-</span><span class="identifier">list</span> <span class="special">)</span> - <span class="identifier">function</span><span class="special">-</span><span class="identifier">body</span> -<span class="identifier">BOOST_SCOPE_EXIT_END</span> -</pre> -<p> - where - </p> -<pre class="programlisting"><span class="identifier">scope</span><span class="special">-</span><span class="identifier">exit</span><span class="special">-</span><span class="identifier">capture</span><span class="special">-</span><span class="identifier">list</span><span class="special">:</span> - <span class="special">(</span> <span class="identifier">scope</span><span class="special">-</span><span class="identifier">exit</span><span class="special">-</span><span class="identifier">capture</span> <span class="special">)</span> - <span class="identifier">scope</span><span class="special">-</span><span class="identifier">exit</span><span class="special">-</span><span class="identifier">capture</span><span class="special">-</span><span class="identifier">list</span> <span class="special">(</span> <span class="identifier">scope</span><span class="special">-</span><span class="identifier">exit</span><span class="special">-</span><span class="identifier">capture</span> <span class="special">)</span> - -<span class="identifier">scope</span><span class="special">-</span><span class="identifier">exit</span><span class="special">-</span><span class="identifier">capture</span><span class="special">:</span> - <span class="identifier">identifier</span> - <span class="special">&</span><span class="identifier">identifier</span> -</pre> -<p> - The <a class="link" href="../index.html" title="Chapter 1. Boost.ScopeExit">ScopeExit</a> declaration schedules an execution - of <code class="computeroutput"><span class="identifier">scope</span><span class="special">-</span><span class="identifier">exit</span><span class="special">-</span><span class="identifier">body</span></code> - at the end of the current scope. The <code class="computeroutput"><span class="identifier">scope</span><span class="special">-</span><span class="identifier">exit</span><span class="special">-</span><span class="identifier">body</span></code> statements are executed in the reverse - order of <a class="link" href="../index.html" title="Chapter 1. Boost.ScopeExit">ScopeExit</a> declarations in the given - scope. The scope must be local. - </p> -<p> - Each <code class="computeroutput"><span class="identifier">identifier</span></code> in <code class="computeroutput"><span class="identifier">scope</span><span class="special">-</span><span class="identifier">exit</span><span class="special">-</span><span class="identifier">capture</span><span class="special">-</span><span class="identifier">list</span></code> must - be a valid name in enclosing scope and it must appear exactly once in the list. - If a <code class="computeroutput"><span class="identifier">scope</span><span class="special">-</span><span class="identifier">exit</span><span class="special">-</span><span class="identifier">capture</span></code> - starts with the ampersand sign <code class="computeroutput"><span class="special">&</span></code>, - the corresponding <code class="computeroutput"><span class="identifier">identifier</span></code> - will be available inside <code class="computeroutput"><span class="identifier">scope</span><span class="special">-</span><span class="identifier">exit</span><span class="special">-</span><span class="identifier">body</span></code>; otherwise, a copy of it will be made - at the point of <a class="link" href="../index.html" title="Chapter 1. Boost.ScopeExit">ScopeExit</a> declaration and - that copy will be available inside <code class="computeroutput"><span class="identifier">scope</span><span class="special">-</span><span class="identifier">exit</span><span class="special">-</span><span class="identifier">body</span></code>. In the latter case, the <code class="computeroutput"><span class="identifier">idenitifer</span></code> must be <code class="computeroutput"><span class="identifier">CopyConstructible</span></code>. - </p> -<p> - Only identifiers listed in <code class="computeroutput"><span class="identifier">scope</span><span class="special">-</span><span class="identifier">exit</span><span class="special">-</span><span class="identifier">capture</span><span class="special">-</span><span class="identifier">list</span></code>, static variables, <code class="computeroutput"><span class="keyword">extern</span></code> - variables and functions, and enumerations from the enclosing scope can be used - inside the <code class="computeroutput"><span class="identifier">scope</span><span class="special">-</span><span class="identifier">exit</span><span class="special">-</span><span class="identifier">body</span></code>. - </p> -<div class="note"><table border="0" summary="Note"> -<tr> -<td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../../../doc/src/images/note.png"></td> -<th align="left">Note</th> -</tr> -<tr><td align="left" valign="top"><p> - <code class="computeroutput"><span class="keyword">this</span></code> pointer is not an identifier - and cannot be passed to <code class="computeroutput"> <span class="identifier">scope</span><span class="special">-</span><span class="identifier">exit</span><span class="special">-</span><span class="identifier">capture</span><span class="special">-</span><span class="identifier">list</span></code>. - </p></td></tr> -</table></div> -<p> - The <a class="link" href="../index.html" title="Chapter 1. Boost.ScopeExit">ScopeExit</a> uses <a href="../../../../../libs/typeof/index.html" target="_top">Boost.Typeof</a> - to determine types of <code class="computeroutput"><span class="identifier">scope</span><span class="special">-</span><span class="identifier">exit</span><span class="special">-</span><span class="identifier">capture</span><span class="special">-</span><span class="identifier">list</span></code> elements. In order to compile code in - <a href="../../../../../libs/typeof/index.html" target="_top">typeof emulation</a> mode, - all types should be registered with <a href="../../../../../doc/html/typeof/refe.html#typeof.regtype" target="_top">BOOST_TYPEOF_REGISTER_TYPE</a> - or <a href="../../../../../doc/html/typeof/refe.html#typeof.regtemp" target="_top">BOOST_TYPEOF_REGISTER_TEMPLATE</a> - macros, or appropriate <a href="../../../../../libs/typeof/index.html" target="_top">Boost.Typeof</a> - headers should be included. - </p> -<a name="ref.boost_scope_exit_tpl"></a><h4> -<a name="id764391"></a> - BOOST_SCOPE_EXIT_TPL - </h4> -<p> - This macro is a workaround for various versions of gcc. These compilers don't - compile <a class="link" href="../index.html" title="Chapter 1. Boost.ScopeExit">ScopeExit</a> declaration inside function - templates. As a workaround, the <code class="computeroutput"><span class="identifier">_TPL</span></code> - suffix should be appended to <code class="computeroutput"><span class="identifier">BOOST_SCOPE_EXIT</span></code>. - </p> -<p> - The problem boils down to the following code: - </p> -<pre class="programlisting"><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">void</span> <span class="identifier">foo</span><span class="special">(</span><span class="identifier">T</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">t</span><span class="special">)</span> <span class="special">{</span> - <span class="keyword">int</span> <span class="identifier">i</span> <span class="special">=</span> <span class="number">0</span><span class="special">;</span> - <span class="keyword">struct</span> <span class="identifier">Local</span> <span class="special">{</span> - <span class="keyword">typedef</span> <span class="identifier">__typeof__</span><span class="special">(</span><span class="identifier">i</span><span class="special">)</span> <span class="identifier">typeof_i</span><span class="special">;</span> - <span class="keyword">typedef</span> <span class="identifier">__typeof__</span><span class="special">(</span><span class="identifier">t</span><span class="special">)</span> <span class="identifier">typeof_t</span><span class="special">;</span> - <span class="special">};</span> - <span class="keyword">typedef</span> <span class="identifier">Local</span><span class="special">::</span><span class="identifier">typeof_i</span> <span class="identifier">i_type</span><span class="special">;</span> - <span class="keyword">typedef</span> <span class="identifier">Local</span><span class="special">::</span><span class="identifier">typeof_t</span> <span class="identifier">t_type</span><span class="special">;</span> -<span class="special">}</span> - -<span class="keyword">int</span> <span class="identifier">main</span><span class="special">()</span> <span class="special">{</span> <span class="identifier">foo</span><span class="special">(</span><span class="number">0</span><span class="special">);</span> <span class="special">}</span> -</pre> -<p> - This can be fixed by adding <code class="computeroutput"><span class="keyword">typename</span></code> - in front of <code class="computeroutput"><span class="identifier">Local</span><span class="special">::</span><span class="identifier">typeof_i</span></code> and <code class="computeroutput"><span class="identifier">Local</span><span class="special">::</span><span class="identifier">typeof_t</span></code>. - </p> -<p> - See also <a href="http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37920" target="_top">GCC - bug 37920</a>. - </p> -<div class="note"><table border="0" summary="Note"> -<tr> -<td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../../../doc/src/images/note.png"></td> -<th align="left">Note</th> -</tr> -<tr><td align="left" valign="top"><p> - Although <code class="computeroutput"><span class="identifier">BOOST_SCOPE_EXIT_TPL</span></code> - has the same suffix as the <code class="computeroutput"><span class="identifier">BOOST_TYPEOF_TPL</span></code>, - it doesn't follow a convention of the <a href="../../../../../libs/typeof/index.html" target="_top">Boost.Typeof</a>. - </p></td></tr> -</table></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 © 2006 -2009 Alexander Nasonov<p> - Distributed under the Boost Software License, Version 1.0. (See accompanying - file LICENSE_1_0.txt or copy at <ulink url="http://www.boost.org/LICENSE_1_0.txt"> - http://www.boost.org/LICENSE_1_0.txt </ulink>) - </p> -</div></td> -</tr></table> -<hr> -<div class="spirit-nav"> -<a accesskey="p" href="conf.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="acknowledge.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a> -</div> -</body> -</html> diff --git a/libs/scope_exit/doc/html/scope_exit/tutorial.html b/libs/scope_exit/doc/html/scope_exit/tutorial.html index 8668d4227a..6db2ec2950 100644 --- a/libs/scope_exit/doc/html/scope_exit/tutorial.html +++ b/libs/scope_exit/doc/html/scope_exit/tutorial.html @@ -3,11 +3,11 @@ <meta http-equiv="Content-Type" content="text/html; charset=US-ASCII"> <title>Tutorial</title> <link rel="stylesheet" href="../../../../../doc/src/boostbook.css" type="text/css"> -<meta name="generator" content="DocBook XSL Stylesheets V1.75.2"> -<link rel="home" href="../index.html" title="Chapter 1. Boost.ScopeExit"> -<link rel="up" href="../index.html" title="Chapter 1. Boost.ScopeExit"> -<link rel="prev" href="../index.html" title="Chapter 1. Boost.ScopeExit"> -<link rel="next" href="alternatives.html" title="Alternatives"> +<meta name="generator" content="DocBook XSL Stylesheets V1.76.1"> +<link rel="home" href="../index.html" title="Chapter 1. Boost.ScopeExit 1.1.0"> +<link rel="up" href="../index.html" title="Chapter 1. Boost.ScopeExit 1.1.0"> +<link rel="prev" href="getting_started.html" title="Getting Started"> +<link rel="next" href="alternatives.html" title="Annex: Alternatives"> </head> <body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> <table cellpadding="2" width="100%"><tr> @@ -20,132 +20,558 @@ </tr></table> <hr> <div class="spirit-nav"> -<a accesskey="p" href="../index.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.html"><img src="../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="alternatives.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a> +<a accesskey="p" href="getting_started.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="alternatives.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a> </div> -<div class="section"> +<div class="section scope_exit_tutorial"> <div class="titlepage"><div><div><h2 class="title" style="clear: both"> -<a name="scope_exit.tutorial"></a> Tutorial</h2></div></div></div> +<a name="scope_exit.tutorial"></a><a class="link" href="tutorial.html" title="Tutorial">Tutorial</a> +</h2></div></div></div> +<div class="toc"><dl> +<dt><span class="section"><a href="tutorial.html#scope_exit.tutorial.capturing_variables">Capturing Variables</a></span></dt> +<dt><span class="section"><a href="tutorial.html#scope_exit.tutorial.capturing_the_object__this_">Capturing + The Object <code class="computeroutput"><span class="keyword">this</span></code></a></span></dt> +<dt><span class="section"><a href="tutorial.html#scope_exit.tutorial.capturing_no_variable">Capturing + No Variable</a></span></dt> +<dt><span class="section"><a href="tutorial.html#scope_exit.tutorial.capturing_all_variables__c__11_only_">Capturing + All Variables (C++11 Only)</a></span></dt> +<dt><span class="section"><a href="tutorial.html#scope_exit.tutorial.template_workaround__gcc_">Template + Workaround (GCC)</a></span></dt> +<dt><span class="section"><a href="tutorial.html#scope_exit.tutorial.same_line_expansions">Same Line Expansions</a></span></dt> +</dl></div> <p> - Imagine that you want to make many modifications to data members of the <code class="computeroutput"><span class="identifier">World</span></code> class in the <code class="computeroutput"><span class="identifier">World</span><span class="special">::</span><span class="identifier">addPerson</span></code> - function. You start with adding a new <code class="computeroutput"><span class="identifier">Person</span></code> - object to a vector of persons: + This section illustrates how to use this library. </p> -<pre class="programlisting"><span class="keyword">void</span> <span class="identifier">World</span><span class="special">::</span><span class="identifier">addPerson</span><span class="special">(</span><span class="identifier">Person</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">person</span><span class="special">)</span> <span class="special">{</span> +<div class="section scope_exit_tutorial_capturing_variables"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="scope_exit.tutorial.capturing_variables"></a><a class="link" href="tutorial.html#scope_exit.tutorial.capturing_variables" title="Capturing Variables">Capturing Variables</a> +</h3></div></div></div> +<p> + Imagine that we want to make many modifications to data members of some + <code class="computeroutput"><span class="identifier">world</span></code> class in its <code class="computeroutput"><span class="identifier">world</span><span class="special">::</span><span class="identifier">add_person</span></code> member function. We start with + adding a new <code class="computeroutput"><span class="identifier">person</span></code> object + to a vector of persons: + </p> +<pre class="programlisting"><span class="keyword">void</span> <span class="identifier">world</span><span class="special">::</span><span class="identifier">add_person</span><span class="special">(</span><span class="identifier">person</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">a_person</span><span class="special">)</span> <span class="special">{</span> <span class="keyword">bool</span> <span class="identifier">commit</span> <span class="special">=</span> <span class="keyword">false</span><span class="special">;</span> - <span class="identifier">m_persons</span><span class="special">.</span><span class="identifier">push_back</span><span class="special">(</span><span class="identifier">person</span><span class="special">);</span> <span class="comment">// (1) direct action -</span></pre> + + <span class="identifier">persons_</span><span class="special">.</span><span class="identifier">push_back</span><span class="special">(</span><span class="identifier">a_person</span><span class="special">);</span> <span class="comment">// (1) direct action</span> + <span class="special">...</span> +</pre> <p> - Some operation down the road may throw an exception and all changes to involved - objects should be rolled back. This all-or-nothing semantic is also known as - <a href="http://www.research.att.com/~bs/glossary.html#Gstrong-guarantee" target="_top">strong - guarantee</a>. - </p> + Some operations down the road may throw an exception and all changes to involved + objects should be rolled back. This all-or-nothing semantic is also known + as <a href="http://www.research.att.com/~bs/glossary.html#Gstrong-guarantee" target="_top">strong + guarantee</a>. + </p> <p> - In particular, last added person must be deleted from <code class="computeroutput"><span class="identifier">m_persons</span></code> - when the function throws. All you need is to define a delayed action (release - of a resource) right after the direct action (resource acquisition): - </p> -<pre class="programlisting"><span class="keyword">void</span> <span class="identifier">World</span><span class="special">::</span><span class="identifier">addPerson</span><span class="special">(</span><span class="identifier">Person</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">aPerson</span><span class="special">)</span> <span class="special">{</span> + In particular, the last added person must be deleted from <code class="computeroutput"><span class="identifier">persons_</span></code> + if the function throws. All we need is to define a delayed action (release + of a resource) right after the direct action (resource acquisition). For + example (see also <a href="../../../test/world.cpp" target="_top"><code class="literal">world.cpp</code></a>): + </p> +<p> +</p> +<pre class="programlisting"><span class="keyword">void</span> <span class="identifier">world</span><span class="special">::</span><span class="identifier">add_person</span><span class="special">(</span><span class="identifier">person</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">a_person</span><span class="special">)</span> <span class="special">{</span> <span class="keyword">bool</span> <span class="identifier">commit</span> <span class="special">=</span> <span class="keyword">false</span><span class="special">;</span> - <span class="identifier">m_persons</span><span class="special">.</span><span class="identifier">push_back</span><span class="special">(</span><span class="identifier">aPerson</span><span class="special">);</span> <span class="comment">// (1) direct action -</span> <span class="identifier">BOOST_SCOPE_EXIT</span><span class="special">(</span> <span class="special">(&</span><span class="identifier">commit</span><span class="special">)(&</span><span class="identifier">m_persons</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">commit</span><span class="special">)</span> - <span class="identifier">m_persons</span><span class="special">.</span><span class="identifier">pop_back</span><span class="special">();</span> <span class="comment">// (2) rollback action -</span> <span class="special">}</span> <span class="identifier">BOOST_SCOPE_EXIT_END</span> - - <span class="comment">// ... // (3) other operations -</span> - <span class="identifier">commit</span> <span class="special">=</span> <span class="keyword">true</span><span class="special">;</span> <span class="comment">// (4) turn all rollback actions into no-op -</span><span class="special">}</span> + + <span class="identifier">persons_</span><span class="special">.</span><span class="identifier">push_back</span><span class="special">(</span><span class="identifier">a_person</span><span class="special">);</span> <span class="comment">// (1) direct action</span> + <span class="comment">// Following block is executed when the enclosing scope exits.</span> + <span class="identifier">BOOST_SCOPE_EXIT</span><span class="special">(&</span><span class="identifier">commit</span><span class="special">,</span> <span class="special">&</span><span class="identifier">persons_</span><span class="special">)</span> <span class="special">{</span> + <span class="keyword">if</span><span class="special">(!</span><span class="identifier">commit</span><span class="special">)</span> <span class="identifier">persons_</span><span class="special">.</span><span class="identifier">pop_back</span><span class="special">();</span> <span class="comment">// (2) rollback action</span> + <span class="special">}</span> <span class="identifier">BOOST_SCOPE_EXIT_END</span> + + <span class="comment">// ... // (3) other operations</span> + + <span class="identifier">commit</span> <span class="special">=</span> <span class="keyword">true</span><span class="special">;</span> <span class="comment">// (4) disable rollback actions</span> +<span class="special">}</span> </pre> <p> - The block below point <code class="computeroutput"><span class="special">(</span><span class="number">1</span><span class="special">)</span></code> is a <a class="link" href="../index.html" title="Chapter 1. Boost.ScopeExit">ScopeExit</a> - declaration. Unlike point <code class="computeroutput"><span class="special">(</span><span class="number">1</span><span class="special">)</span></code>, an execution of the <a class="link" href="../index.html" title="Chapter 1. Boost.ScopeExit">ScopeExit</a> - body will be delayed until the end of the current scope. In this case it will - be executed either after point <code class="computeroutput"><span class="special">(</span><span class="number">4</span><span class="special">)</span></code> or on any - exception. - </p> + </p> <p> - The <a class="link" href="../index.html" title="Chapter 1. Boost.ScopeExit">ScopeExit</a> declaration starts with <code class="computeroutput"><span class="identifier">BOOST_SCOPE_EXIT</span></code> macro invocation which accepts - <a href="../../../../../libs/preprocessor/index.html" target="_top">Boost.Preprocessor sequence</a> - of captured variables. If a capture starts with the ampersand sign <code class="computeroutput"><span class="special">&</span></code>, a reference to the captured variable - will be available inside the <a class="link" href="../index.html" title="Chapter 1. Boost.ScopeExit">ScopeExit</a> body; - otherwise, a copy of the variable will be made after the point <code class="computeroutput"><span class="special">(</span><span class="number">1</span><span class="special">)</span></code> - and only the copy will be available inside the body. - </p> + The block below point <code class="literal">(1)</code> is a <a class="link" href="../index.html" title="Chapter 1. Boost.ScopeExit 1.1.0">Boost.ScopeExit</a> + declaration. Unlike point <code class="literal">(1)</code>, an execution of the <a class="link" href="../index.html" title="Chapter 1. Boost.ScopeExit 1.1.0">Boost.ScopeExit</a> body will be delayed until the + end of the current scope. In this case it will be executed either after point + <code class="literal">(4)</code> or on any exception. (On various versions of the GCC + compiler, it is necessary to use <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT_TPL.html" title="Macro BOOST_SCOPE_EXIT_TPL">BOOST_SCOPE_EXIT_TPL</a></code> + instead of <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT.html" title="Macro BOOST_SCOPE_EXIT">BOOST_SCOPE_EXIT</a></code> + within templates, see later in this section for details.) + </p> <p> - In the example above, variables <code class="computeroutput"><span class="identifier">commit</span></code> - and <code class="computeroutput"><span class="identifier">m_persons</span></code> are passed by - reference because the final value of the <code class="computeroutput"><span class="identifier">commit</span></code> - variable should be used to determine whether to execute rollback action or - not and the action should modify the <code class="computeroutput"><span class="identifier">m_persons</span></code> - object, not its copy. This is a most common case but passing a variable by - value is sometimes useful as well. - </p> + The <a class="link" href="../index.html" title="Chapter 1. Boost.ScopeExit 1.1.0">Boost.ScopeExit</a> declaration starts + with the <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT.html" title="Macro BOOST_SCOPE_EXIT">BOOST_SCOPE_EXIT</a></code> macro + invocation which accepts a comma-separated list of captured variables (a + <a href="http://www.boost.org/libs/preprocessor" target="_top">Boost.Preprocessor</a> + sequence is also accepted for compilers that do not support variadic macros + and for backward compatibility with older versions of this library, see the + <a class="link" href="no_variadic_macros.html" title="Annex: No Variadic Macros">No Variadic Macros</a> section). + If a capture starts with the ampersand sign <code class="computeroutput"><span class="special">&</span></code>, + a reference to the captured variable will be available inside the <a class="link" href="../index.html" title="Chapter 1. Boost.ScopeExit 1.1.0">Boost.ScopeExit</a> + body; otherwise, a copy of the variable will be made after the <a class="link" href="../index.html" title="Chapter 1. Boost.ScopeExit 1.1.0">Boost.ScopeExit</a> + declaration at point <code class="literal">(1)</code> and only the copy will be available + inside the body (in this case, the captured variable's type must be <a href="http://www.boost.org/doc/libs/release/doc/html/CopyConstructible.html" target="_top"><code class="computeroutput"><span class="identifier">CopyConstructible</span></code></a>). + </p> <p> - Consider a more complex case where <code class="computeroutput"><span class="identifier">World</span><span class="special">::</span><span class="identifier">addPerson</span></code> - can save intermediate states at some points and roll back to the last saved - state. You can use <code class="computeroutput"><span class="identifier">Person</span><span class="special">::</span><span class="identifier">m_evolution</span></code> to store a version of changes - and increment it to cancel all rollback actions associated with those changes. - </p> + In the example above, the variables <code class="computeroutput"><span class="identifier">commit</span></code> + and <code class="computeroutput"><span class="identifier">persons_</span></code> are captured + by reference because the final value of the <code class="computeroutput"><span class="identifier">commit</span></code> + variable should be used to determine whether to execute rollback actions + or not, and the action should modify the <code class="computeroutput"><span class="identifier">persons_</span></code> + object, not its copy. This is the most common case but passing a variable + by value is sometimes useful as well. + </p> <p> - If you pass a current value of <code class="computeroutput"><span class="identifier">m_evolution</span></code> - stored in the <code class="computeroutput"><span class="identifier">checkpoint</span></code> variable - by value, it will remain unchanged until the end of aa scope and you can compare - it with the final value of the <code class="computeroutput"><span class="identifier">m_evolution</span></code>. - If the latter wasn't incremented since you saved it, the rollback action inside - the block should be executed: - </p> -<pre class="programlisting"><span class="keyword">void</span> <span class="identifier">World</span><span class="special">::</span><span class="identifier">addPerson</span><span class="special">(</span><span class="identifier">Person</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">aPerson</span><span class="special">)</span> <span class="special">{</span> - <span class="identifier">m_persons</span><span class="special">.</span><span class="identifier">push_back</span><span class="special">(</span><span class="identifier">aPerson</span><span class="special">);</span> + Finally, the end of the <a class="link" href="../index.html" title="Chapter 1. Boost.ScopeExit 1.1.0">Boost.ScopeExit</a> + body must be marked by the <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT_END.html" title="Macro BOOST_SCOPE_EXIT_END">BOOST_SCOPE_EXIT_END</a></code> + macro which must follow the closing curly bracket <code class="computeroutput"><span class="special">}</span></code> + of the <a class="link" href="../index.html" title="Chapter 1. Boost.ScopeExit 1.1.0">Boost.ScopeExit</a> body. + </p> +<div class="important"><table border="0" summary="Important"> +<tr> +<td rowspan="2" align="center" valign="top" width="25"><img alt="[Important]" src="../../../../../doc/src/images/important.png"></td> +<th align="left">Important</th> +</tr> +<tr><td align="left" valign="top"><p> + In order to comply with the <a href="http://www.stlport.org/doc/exception_safety.html" target="_top">STL + exception safety requirements</a>, the <a class="link" href="../index.html" title="Chapter 1. Boost.ScopeExit 1.1.0">Boost.ScopeExit</a> + body must never throw (because the library implementation executes the + body within a destructor call). This is true for all <a class="link" href="../index.html" title="Chapter 1. Boost.ScopeExit 1.1.0">Boost.ScopeExit</a> + macros (including <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT_TPL.html" title="Macro BOOST_SCOPE_EXIT_TPL">BOOST_SCOPE_EXIT_TPL</a></code> + and <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT_ALL.html" title="Macro BOOST_SCOPE_EXIT_ALL">BOOST_SCOPE_EXIT_ALL</a></code> + seen below) on both C++03 and C++11. + </p></td></tr> +</table></div> +<p> + Consider a more complex example where <code class="computeroutput"><span class="identifier">world</span><span class="special">::</span><span class="identifier">add_person</span></code> + can save intermediate states at some point and roll back to the last saved + state. We use <code class="computeroutput"><span class="identifier">person</span><span class="special">::</span><span class="identifier">evolution_</span></code> to store a version of the changes + and increment it to cancel all rollback actions associated with those changes. + If we pass a current value of <code class="computeroutput"><span class="identifier">evolution_</span></code> + stored in the <code class="computeroutput"><span class="identifier">checkpoint</span></code> + variable by value, it remains unchanged within the <a class="link" href="../index.html" title="Chapter 1. Boost.ScopeExit 1.1.0">Boost.ScopeExit</a> + body so we can compare it with the final value of <code class="computeroutput"><span class="identifier">evolution_</span></code>. + If the latter was not incremented since we saved it, the rollback action + inside the <a class="link" href="../index.html" title="Chapter 1. Boost.ScopeExit 1.1.0">Boost.ScopeExit</a> body should + be executed. For example (see also <a href="../../../test/world_checkpoint.cpp" target="_top"><code class="literal">world_checkpoint.cpp</code></a>): + </p> +<p> +</p> +<pre class="programlisting"><span class="keyword">void</span> <span class="identifier">world</span><span class="special">::</span><span class="identifier">add_person</span><span class="special">(</span><span class="identifier">person</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">a_person</span><span class="special">)</span> <span class="special">{</span> + <span class="identifier">persons_</span><span class="special">.</span><span class="identifier">push_back</span><span class="special">(</span><span class="identifier">a_person</span><span class="special">);</span> - <span class="comment">// This block must be no-throw -</span> <span class="identifier">Person</span><span class="special">&</span> <span class="identifier">person</span> <span class="special">=</span> <span class="identifier">m_persons</span><span class="special">.</span><span class="identifier">back</span><span class="special">();</span> - <span class="identifier">Person</span><span class="special">::</span><span class="identifier">evolution_t</span> <span class="identifier">checkpoint</span> <span class="special">=</span> <span class="identifier">person</span><span class="special">.</span><span class="identifier">m_evolution</span><span class="special">;</span> + <span class="comment">// This block must be no-throw.</span> + <span class="identifier">person</span><span class="special">&</span> <span class="identifier">p</span> <span class="special">=</span> <span class="identifier">persons_</span><span class="special">.</span><span class="identifier">back</span><span class="special">();</span> + <span class="identifier">person</span><span class="special">::</span><span class="identifier">evolution_t</span> <span class="identifier">checkpoint</span> <span class="special">=</span> <span class="identifier">p</span><span class="special">.</span><span class="identifier">evolution</span><span class="special">;</span> + <span class="identifier">BOOST_SCOPE_EXIT</span><span class="special">(</span><span class="identifier">checkpoint</span><span class="special">,</span> <span class="special">&</span><span class="identifier">p</span><span class="special">,</span> <span class="special">&</span><span class="identifier">persons_</span><span class="special">)</span> <span class="special">{</span> + <span class="keyword">if</span><span class="special">(</span><span class="identifier">checkpoint</span> <span class="special">==</span> <span class="identifier">p</span><span class="special">.</span><span class="identifier">evolution</span><span class="special">)</span> <span class="identifier">persons_</span><span class="special">.</span><span class="identifier">pop_back</span><span class="special">();</span> + <span class="special">}</span> <span class="identifier">BOOST_SCOPE_EXIT_END</span> - <span class="identifier">BOOST_SCOPE_EXIT</span><span class="special">(</span> <span class="special">(</span><span class="identifier">checkpoint</span><span class="special">)(&</span><span class="identifier">person</span><span class="special">)(&</span><span class="identifier">m_persons</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">checkpoint</span> <span class="special">==</span> <span class="identifier">person</span><span class="special">.</span><span class="identifier">m_evolution</span><span class="special">)</span> - <span class="identifier">m_persons</span><span class="special">.</span><span class="identifier">pop_back</span><span class="special">();</span> + <span class="comment">// ...</span> + + <span class="identifier">checkpoint</span> <span class="special">=</span> <span class="special">++</span><span class="identifier">p</span><span class="special">.</span><span class="identifier">evolution</span><span class="special">;</span> + + <span class="comment">// Assign new identifier to the person.</span> + <span class="identifier">person</span><span class="special">::</span><span class="identifier">id_t</span> <span class="keyword">const</span> <span class="identifier">prev_id</span> <span class="special">=</span> <span class="identifier">p</span><span class="special">.</span><span class="identifier">id</span><span class="special">;</span> + <span class="identifier">p</span><span class="special">.</span><span class="identifier">id</span> <span class="special">=</span> <span class="identifier">next_id_</span><span class="special">++;</span> + <span class="identifier">BOOST_SCOPE_EXIT</span><span class="special">(</span><span class="identifier">checkpoint</span><span class="special">,</span> <span class="special">&</span><span class="identifier">p</span><span class="special">,</span> <span class="special">&</span><span class="identifier">next_id_</span><span class="special">,</span> <span class="identifier">prev_id</span><span class="special">)</span> <span class="special">{</span> + <span class="keyword">if</span><span class="special">(</span><span class="identifier">checkpoint</span> <span class="special">==</span> <span class="identifier">p</span><span class="special">.</span><span class="identifier">evolution</span><span class="special">)</span> <span class="special">{</span> + <span class="identifier">next_id_</span> <span class="special">=</span> <span class="identifier">p</span><span class="special">.</span><span class="identifier">id</span><span class="special">;</span> + <span class="identifier">p</span><span class="special">.</span><span class="identifier">id</span> <span class="special">=</span> <span class="identifier">prev_id</span><span class="special">;</span> + <span class="special">}</span> <span class="special">}</span> <span class="identifier">BOOST_SCOPE_EXIT_END</span> - <span class="comment">// ... -</span> - <span class="identifier">checkpoint</span> <span class="special">=</span> <span class="special">++</span><span class="identifier">person</span><span class="special">.</span><span class="identifier">m_evolution</span><span class="special">;</span> + <span class="comment">// ...</span> - <span class="comment">// Assign new id to the person -</span> <span class="identifier">World</span><span class="special">::</span><span class="identifier">id_t</span> <span class="keyword">const</span> <span class="identifier">prev_id</span> <span class="special">=</span> <span class="identifier">person</span><span class="special">.</span><span class="identifier">m_id</span><span class="special">;</span> - <span class="identifier">person</span><span class="special">.</span><span class="identifier">m_id</span> <span class="special">=</span> <span class="identifier">m_next_id</span><span class="special">++;</span> - <span class="identifier">BOOST_SCOPE_EXIT</span><span class="special">(</span> <span class="special">(</span><span class="identifier">checkpoint</span><span class="special">)(&</span><span class="identifier">person</span><span class="special">)(&</span><span class="identifier">m_next_id</span><span class="special">)(</span><span class="identifier">prev_id</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">checkpoint</span> <span class="special">==</span> <span class="identifier">person</span><span class="special">.</span><span class="identifier">m_evolution</span><span class="special">)</span> <span class="special">{</span> - <span class="identifier">m_next_id</span> <span class="special">=</span> <span class="identifier">person</span><span class="special">.</span><span class="identifier">m_id</span><span class="special">;</span> - <span class="identifier">person</span><span class="special">.</span><span class="identifier">m_id</span> <span class="special">=</span> <span class="identifier">prev_id</span><span class="special">;</span> + <span class="identifier">checkpoint</span> <span class="special">=</span> <span class="special">++</span><span class="identifier">p</span><span class="special">.</span><span class="identifier">evolution</span><span class="special">;</span> +<span class="special">}</span> +</pre> +<p> + </p> +<p> + When multiple <a class="link" href="../index.html" title="Chapter 1. Boost.ScopeExit 1.1.0">Boost.ScopeExit</a> blocks are + declared within the same enclosing scope, the <a class="link" href="../index.html" title="Chapter 1. Boost.ScopeExit 1.1.0">Boost.ScopeExit</a> + bodies are executed in the reversed order of their declarations. + </p> +</div> +<div class="section scope_exit_tutorial_capturing_the_object__this_"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="scope_exit.tutorial.capturing_the_object__this_"></a><a class="link" href="tutorial.html#scope_exit.tutorial.capturing_the_object__this_" title="Capturing The Object this">Capturing + The Object <code class="computeroutput"><span class="keyword">this</span></code></a> +</h3></div></div></div> +<p> + Within a member function, it is also possible to capture the object <code class="computeroutput"><span class="keyword">this</span></code>. However, the special symbol <code class="computeroutput"><span class="identifier">this_</span></code> must be used instead of <code class="computeroutput"><span class="keyword">this</span></code> in the <a class="link" href="../index.html" title="Chapter 1. Boost.ScopeExit 1.1.0">Boost.ScopeExit</a> + declaration and body to capture and access the object. For example (see also + <a href="../../../test/world_this.cpp" target="_top"><code class="literal">world_this.cpp</code></a>): + </p> +<p> +</p> +<pre class="programlisting"><span class="identifier">BOOST_SCOPE_EXIT</span><span class="special">(&</span><span class="identifier">commit</span><span class="special">,</span> <span class="identifier">this_</span><span class="special">)</span> <span class="special">{</span> <span class="comment">// Capture object `this_`.</span> + <span class="keyword">if</span><span class="special">(!</span><span class="identifier">commit</span><span class="special">)</span> <span class="identifier">this_</span><span class="special">-></span><span class="identifier">persons_</span><span class="special">.</span><span class="identifier">pop_back</span><span class="special">();</span> +<span class="special">}</span> <span class="identifier">BOOST_SCOPE_EXIT_END</span> +</pre> +<p> + </p> +<p> + It is not possible to capture the object <code class="computeroutput"><span class="identifier">this_</span></code> + by reference because C++ does not allow to take a reference to <code class="computeroutput"><span class="keyword">this</span></code>. If the enclosing member function is + constant then the captured object will also be constant, otherwise the captured + object will be mutable. + </p> +</div> +<div class="section scope_exit_tutorial_capturing_no_variable"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="scope_exit.tutorial.capturing_no_variable"></a><a class="link" href="tutorial.html#scope_exit.tutorial.capturing_no_variable" title="Capturing No Variable">Capturing + No Variable</a> +</h3></div></div></div> +<p> + A <a class="link" href="../index.html" title="Chapter 1. Boost.ScopeExit 1.1.0">Boost.ScopeExit</a> declaration can also + capture no variable. In this case, the list of captured variables is replaced + by the <code class="computeroutput"><span class="keyword">void</span></code> keyword (similarly + to the C++ syntax that allows to declare a function with no parameter using + <code class="literal"><span class="emphasis"><em>result-type function-name</em></span></code><code class="computeroutput"><span class="special">(</span><span class="keyword">void</span><span class="special">)</span></code>). + <sup>[<a name="scope_exit.tutorial.capturing_no_variable.f0" href="#ftn.scope_exit.tutorial.capturing_no_variable.f0" class="footnote">3</a>]</sup> For example, this can be useful when the <a class="link" href="../index.html" title="Chapter 1. Boost.ScopeExit 1.1.0">Boost.ScopeExit</a> + body only needs to access global variables (see also <a href="../../../test/world_void.cpp" target="_top"><code class="literal">world_void.cpp</code></a>): + </p> +<p> +</p> +<pre class="programlisting"><span class="keyword">struct</span> <span class="identifier">world_t</span> <span class="special">{</span> + <span class="identifier">std</span><span class="special">::</span><span class="identifier">vector</span><span class="special"><</span><span class="identifier">person</span><span class="special">></span> <span class="identifier">persons</span><span class="special">;</span> + <span class="keyword">bool</span> <span class="identifier">commit</span><span class="special">;</span> +<span class="special">}</span> <span class="identifier">world</span><span class="special">;</span> <span class="comment">// Global variable.</span> + +<span class="keyword">void</span> <span class="identifier">add_person</span><span class="special">(</span><span class="identifier">person</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">a_person</span><span class="special">)</span> <span class="special">{</span> + <span class="identifier">world</span><span class="special">.</span><span class="identifier">commit</span> <span class="special">=</span> <span class="keyword">false</span><span class="special">;</span> + <span class="identifier">world</span><span class="special">.</span><span class="identifier">persons</span><span class="special">.</span><span class="identifier">push_back</span><span class="special">(</span><span class="identifier">a_person</span><span class="special">);</span> + + <span class="identifier">BOOST_SCOPE_EXIT</span><span class="special">(</span><span class="keyword">void</span><span class="special">)</span> <span class="special">{</span> <span class="comment">// No captures.</span> + <span class="keyword">if</span><span class="special">(!</span><span class="identifier">world</span><span class="special">.</span><span class="identifier">commit</span><span class="special">)</span> <span class="identifier">world</span><span class="special">.</span><span class="identifier">persons</span><span class="special">.</span><span class="identifier">pop_back</span><span class="special">();</span> + <span class="special">}</span> <span class="identifier">BOOST_SCOPE_EXIT_END</span> + + <span class="comment">// ...</span> + + <span class="identifier">world</span><span class="special">.</span><span class="identifier">commit</span> <span class="special">=</span> <span class="keyword">true</span><span class="special">;</span> +<span class="special">}</span> +</pre> +<p> + </p> +<p> + (Both compilers with and without variadic macros use this same syntax for + capturing no variable, see the <a class="link" href="no_variadic_macros.html" title="Annex: No Variadic Macros">No + Variadic Macros</a> section for more information.) + </p> +</div> +<div class="section scope_exit_tutorial_capturing_all_variables__c__11_only_"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="scope_exit.tutorial.capturing_all_variables__c__11_only_"></a><a class="link" href="tutorial.html#scope_exit.tutorial.capturing_all_variables__c__11_only_" title="Capturing All Variables (C++11 Only)">Capturing + All Variables (C++11 Only)</a> +</h3></div></div></div> +<p> + On C++11 compliers, it is also possible to capture all the variables in scope + without naming them one-by-one using the special macro <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT_ALL.html" title="Macro BOOST_SCOPE_EXIT_ALL">BOOST_SCOPE_EXIT_ALL</a></code> + instead of <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT.html" title="Macro BOOST_SCOPE_EXIT">BOOST_SCOPE_EXIT</a></code>. + <sup>[<a name="scope_exit.tutorial.capturing_all_variables__c__11_only_.f0" href="#ftn.scope_exit.tutorial.capturing_all_variables__c__11_only_.f0" class="footnote">4</a>]</sup> + </p> +<p> + Following the same syntax adopted by C++11 lambda functions, the <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT_ALL.html" title="Macro BOOST_SCOPE_EXIT_ALL">BOOST_SCOPE_EXIT_ALL</a></code> macro accepts + a comma-separated list of captures which must start with either <code class="computeroutput"><span class="special">&</span></code> or <code class="computeroutput"><span class="special">=</span></code> + to capture all variables in scope respectively by reference or by value (note + that no variable name is specified by these leading captures). Additional + captures of specific variables can follow the leading <code class="computeroutput"><span class="special">&</span></code> + or <code class="computeroutput"><span class="special">=</span></code> and they will override + the default reference or value captures. For example (see also <a href="../../../test/world_checkpoint_all.cpp" target="_top"><code class="literal">world_checkpoint_all.cpp</code></a>): + </p> +<p> +</p> +<pre class="programlisting"><span class="keyword">void</span> <span class="identifier">world</span><span class="special">::</span><span class="identifier">add_person</span><span class="special">(</span><span class="identifier">person</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">a_person</span><span class="special">)</span> <span class="special">{</span> + <span class="identifier">persons_</span><span class="special">.</span><span class="identifier">push_back</span><span class="special">(</span><span class="identifier">a_person</span><span class="special">);</span> + + <span class="comment">// This block must be no-throw.</span> + <span class="identifier">person</span><span class="special">&</span> <span class="identifier">p</span> <span class="special">=</span> <span class="identifier">persons_</span><span class="special">.</span><span class="identifier">back</span><span class="special">();</span> + <span class="identifier">person</span><span class="special">::</span><span class="identifier">evolution_t</span> <span class="identifier">checkpoint</span> <span class="special">=</span> <span class="identifier">p</span><span class="special">.</span><span class="identifier">evolution</span><span class="special">;</span> + <span class="comment">// Capture all by reference `&`, but `checkpoint` and `this` (C++11 only).</span> + <span class="identifier">BOOST_SCOPE_EXIT_ALL</span><span class="special">(&,</span> <span class="identifier">checkpoint</span><span class="special">,</span> <span class="keyword">this</span><span class="special">)</span> <span class="special">{</span> <span class="comment">// Use `this` (not `this_`).</span> + <span class="keyword">if</span><span class="special">(</span><span class="identifier">checkpoint</span> <span class="special">==</span> <span class="identifier">p</span><span class="special">.</span><span class="identifier">evolution</span><span class="special">)</span> <span class="keyword">this</span><span class="special">-></span><span class="identifier">persons_</span><span class="special">.</span><span class="identifier">pop_back</span><span class="special">();</span> + <span class="special">};</span> <span class="comment">// Use `;` (not `SCOPE_EXIT_END`).</span> + + <span class="comment">// ...</span> + + <span class="identifier">checkpoint</span> <span class="special">=</span> <span class="special">++</span><span class="identifier">p</span><span class="special">.</span><span class="identifier">evolution</span><span class="special">;</span> + + <span class="comment">// Assign new identifier to the person.</span> + <span class="identifier">person</span><span class="special">::</span><span class="identifier">id_t</span> <span class="keyword">const</span> <span class="identifier">prev_id</span> <span class="special">=</span> <span class="identifier">p</span><span class="special">.</span><span class="identifier">id</span><span class="special">;</span> + <span class="identifier">p</span><span class="special">.</span><span class="identifier">id</span> <span class="special">=</span> <span class="identifier">next_id_</span><span class="special">++;</span> + <span class="comment">// Capture all by value `=`, but `p` (C++11 only).</span> + <span class="identifier">BOOST_SCOPE_EXIT_ALL</span><span class="special">(=,</span> <span class="special">&</span><span class="identifier">p</span><span class="special">)</span> <span class="special">{</span> + <span class="keyword">if</span><span class="special">(</span><span class="identifier">checkpoint</span> <span class="special">==</span> <span class="identifier">p</span><span class="special">.</span><span class="identifier">evolution</span><span class="special">)</span> <span class="special">{</span> + <span class="keyword">this</span><span class="special">-></span><span class="identifier">next_id_</span> <span class="special">=</span> <span class="identifier">p</span><span class="special">.</span><span class="identifier">id</span><span class="special">;</span> + <span class="identifier">p</span><span class="special">.</span><span class="identifier">id</span> <span class="special">=</span> <span class="identifier">prev_id</span><span class="special">;</span> <span class="special">}</span> + <span class="special">};</span> + + <span class="comment">// ...</span> + + <span class="identifier">checkpoint</span> <span class="special">=</span> <span class="special">++</span><span class="identifier">p</span><span class="special">.</span><span class="identifier">evolution</span><span class="special">;</span> +<span class="special">}</span> +</pre> +<p> + </p> +<p> + The first <a class="link" href="../index.html" title="Chapter 1. Boost.ScopeExit 1.1.0">Boost.ScopeExit</a> declaration captures + all variables in scope by reference but the variable <code class="computeroutput"><span class="identifier">checkpoint</span></code> + and the object <code class="computeroutput"><span class="keyword">this</span></code> which are + explicitly captured by value (in particular, <code class="computeroutput"><span class="identifier">p</span></code> + and <code class="computeroutput"><span class="identifier">persons_</span></code> are implicitly + captured by reference here). The second <a class="link" href="../index.html" title="Chapter 1. Boost.ScopeExit 1.1.0">Boost.ScopeExit</a> + declaration instead captures all variables in scope by value but <code class="computeroutput"><span class="identifier">p</span></code> which is explicitly captured by reference + (in particular, <code class="computeroutput"><span class="identifier">checkpoint</span></code>, + <code class="computeroutput"><span class="identifier">prev_id</span></code>, and <code class="computeroutput"><span class="keyword">this</span></code> are implicitly captured by value here). + </p> +<p> + Note that the <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT_ALL.html" title="Macro BOOST_SCOPE_EXIT_ALL">BOOST_SCOPE_EXIT_ALL</a></code> + macro follows the C++11 lambda function syntax which is unfortunately different + from the <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT.html" title="Macro BOOST_SCOPE_EXIT">BOOST_SCOPE_EXIT</a></code> macro + syntax. In particular: + </p> +<div class="orderedlist"><ol class="orderedlist" type="1"> +<li class="listitem"> + The <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT_ALL.html" title="Macro BOOST_SCOPE_EXIT_ALL">BOOST_SCOPE_EXIT_ALL</a></code> + macro cannot capture data members without capturing the object <code class="computeroutput"><span class="keyword">this</span></code> while that is not the case for <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT.html" title="Macro BOOST_SCOPE_EXIT">BOOST_SCOPE_EXIT</a></code>. <sup>[<a name="scope_exit.tutorial.capturing_all_variables__c__11_only_.f1" href="#ftn.scope_exit.tutorial.capturing_all_variables__c__11_only_.f1" class="footnote">5</a>]</sup> + </li> +<li class="listitem"> + The <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT_ALL.html" title="Macro BOOST_SCOPE_EXIT_ALL">BOOST_SCOPE_EXIT_ALL</a></code> + macro captures the object in scope using <code class="computeroutput"><span class="keyword">this</span></code> + instead of <code class="computeroutput"><span class="identifier">this_</span></code>. <sup>[<a name="scope_exit.tutorial.capturing_all_variables__c__11_only_.f2" href="#ftn.scope_exit.tutorial.capturing_all_variables__c__11_only_.f2" class="footnote">6</a>]</sup> + </li> +<li class="listitem"> + The <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT_ALL.html" title="Macro BOOST_SCOPE_EXIT_ALL">BOOST_SCOPE_EXIT_ALL</a></code> + body is terminated by a semicolon <code class="computeroutput"><span class="special">;</span></code> + instead than by the <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT_END.html" title="Macro BOOST_SCOPE_EXIT_END">BOOST_SCOPE_EXIT_END</a></code> + macro. + </li> +</ol></div> +<p> + If programmers define the configuration macro <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT_CONFIG_USE_LAMBDAS.html" title="Macro BOOST_SCOPE_EXIT_CONFIG_USE_LAMBDAS">BOOST_SCOPE_EXIT_CONFIG_USE_LAMBDAS</a></code> + then the <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT.html" title="Macro BOOST_SCOPE_EXIT">BOOST_SCOPE_EXIT</a></code> macro + implementation will use C++11 lamda functions and the <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT.html" title="Macro BOOST_SCOPE_EXIT">BOOST_SCOPE_EXIT</a></code> + macro will follow the same syntax of <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT_ALL.html" title="Macro BOOST_SCOPE_EXIT_ALL">BOOST_SCOPE_EXIT_ALL</a></code> + macro, which is the C++11 lambda function syntax. However, <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT.html" title="Macro BOOST_SCOPE_EXIT">BOOST_SCOPE_EXIT</a></code> + will no longer be backward compatible and older code using <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT.html" title="Macro BOOST_SCOPE_EXIT">BOOST_SCOPE_EXIT</a></code> + might no longer compile (if data members were explicitly captured). + </p> +</div> +<div class="section scope_exit_tutorial_template_workaround__gcc_"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="scope_exit.tutorial.template_workaround__gcc_"></a><a class="link" href="tutorial.html#scope_exit.tutorial.template_workaround__gcc_" title="Template Workaround (GCC)">Template + Workaround (GCC)</a> +</h3></div></div></div> +<p> + Various versions of the GCC compiler do not compile <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT.html" title="Macro BOOST_SCOPE_EXIT">BOOST_SCOPE_EXIT</a></code> + inside templates (see the <a href="../reference.html" target="_top">Reference</a> section + for more information). As a workaround, <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT_TPL.html" title="Macro BOOST_SCOPE_EXIT_TPL">BOOST_SCOPE_EXIT_TPL</a></code> + should be used instead of <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT.html" title="Macro BOOST_SCOPE_EXIT">BOOST_SCOPE_EXIT</a></code> + in these cases. <sup>[<a name="scope_exit.tutorial.template_workaround__gcc_.f0" href="#ftn.scope_exit.tutorial.template_workaround__gcc_.f0" class="footnote">7</a>]</sup> The <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT_TPL.html" title="Macro BOOST_SCOPE_EXIT_TPL">BOOST_SCOPE_EXIT_TPL</a></code> + macro has the exact same syntax of <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT.html" title="Macro BOOST_SCOPE_EXIT">BOOST_SCOPE_EXIT</a></code>. + For example (see also <a href="../../../test/world_tpl.cpp" target="_top"><code class="literal">world_tpl.cpp</code></a>): + </p> +<p> +</p> +<pre class="programlisting"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">Person</span><span class="special">></span> +<span class="keyword">void</span> <span class="identifier">world</span><span class="special"><</span><span class="identifier">Person</span><span class="special">>::</span><span class="identifier">add_person</span><span class="special">(</span><span class="identifier">Person</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">a_person</span><span class="special">)</span> <span class="special">{</span> + <span class="keyword">bool</span> <span class="identifier">commit</span> <span class="special">=</span> <span class="keyword">false</span><span class="special">;</span> + <span class="identifier">persons_</span><span class="special">.</span><span class="identifier">push_back</span><span class="special">(</span><span class="identifier">a_person</span><span class="special">);</span> + + <span class="identifier">BOOST_SCOPE_EXIT_TPL</span><span class="special">(&</span><span class="identifier">commit</span><span class="special">,</span> <span class="identifier">this_</span><span class="special">)</span> <span class="special">{</span> <span class="comment">// Use `_TPL` postfix.</span> + <span class="keyword">if</span><span class="special">(!</span><span class="identifier">commit</span><span class="special">)</span> <span class="identifier">this_</span><span class="special">-></span><span class="identifier">persons_</span><span class="special">.</span><span class="identifier">pop_back</span><span class="special">();</span> <span class="special">}</span> <span class="identifier">BOOST_SCOPE_EXIT_END</span> - <span class="comment">// ... -</span> - <span class="identifier">checkpoint</span> <span class="special">=</span> <span class="special">++</span><span class="identifier">person</span><span class="special">.</span><span class="identifier">m_evolution</span><span class="special">;</span> + <span class="comment">// ...</span> + + <span class="identifier">commit</span> <span class="special">=</span> <span class="keyword">true</span><span class="special">;</span> <span class="special">}</span> </pre> <p> - Full code listing can be found in <a href="../../../example/world.cpp" target="_top">world.cpp</a>. - </p> + </p> +<p> + It is recommended to always use <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT_TPL.html" title="Macro BOOST_SCOPE_EXIT_TPL">BOOST_SCOPE_EXIT_TPL</a></code> + within templates so to maximize portability among different compilers. + </p> +</div> +<div class="section scope_exit_tutorial_same_line_expansions"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="scope_exit.tutorial.same_line_expansions"></a><a class="link" href="tutorial.html#scope_exit.tutorial.same_line_expansions" title="Same Line Expansions">Same Line Expansions</a> +</h3></div></div></div> +<p> + In general, it is not possible to expand the <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT.html" title="Macro BOOST_SCOPE_EXIT">BOOST_SCOPE_EXIT</a></code>, + <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT_TPL.html" title="Macro BOOST_SCOPE_EXIT_TPL">BOOST_SCOPE_EXIT_TPL</a></code>, + <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT_END.html" title="Macro BOOST_SCOPE_EXIT_END">BOOST_SCOPE_EXIT_END</a></code>, and + <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT_ALL.html" title="Macro BOOST_SCOPE_EXIT_ALL">BOOST_SCOPE_EXIT_ALL</a></code> macros + multiple times on the same line. <sup>[<a name="scope_exit.tutorial.same_line_expansions.f0" href="#ftn.scope_exit.tutorial.same_line_expansions.f0" class="footnote">8</a>]</sup> + </p> +<p> + Therefore, this library provides additional macros <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT_ID.html" title="Macro BOOST_SCOPE_EXIT_ID">BOOST_SCOPE_EXIT_ID</a></code>, + <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT_ID_TPL.html" title="Macro BOOST_SCOPE_EXIT_ID_TPL">BOOST_SCOPE_EXIT_ID_TPL</a></code>, + <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT_END_ID.html" title="Macro BOOST_SCOPE_EXIT_END_ID">BOOST_SCOPE_EXIT_END_ID</a></code>, + and <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT_ALL_ID.html" title="Macro BOOST_SCOPE_EXIT_ALL_ID">BOOST_SCOPE_EXIT_ALL_ID</a></code> + which can be expanded multiple times on the same line as long as programmers + specify a unique identifiers as the macros' first parameters. The unique + identifier can be any token (not just numeric) that can be concatenated by + the C++ preprocessor (e.g., <code class="computeroutput"><span class="identifier">scope_exit_number_1_at_line_123</span></code>). + <sup>[<a name="scope_exit.tutorial.same_line_expansions.f1" href="#ftn.scope_exit.tutorial.same_line_expansions.f1" class="footnote">9</a>]</sup> + </p> +<p> + The <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT_ID.html" title="Macro BOOST_SCOPE_EXIT_ID">BOOST_SCOPE_EXIT_ID</a></code>, + <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT_ID_TPL.html" title="Macro BOOST_SCOPE_EXIT_ID_TPL">BOOST_SCOPE_EXIT_ID_TPL</a></code>, + and <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT_ALL_ID.html" title="Macro BOOST_SCOPE_EXIT_ALL_ID">BOOST_SCOPE_EXIT_ALL_ID</a></code> + macros accept a capture list using the exact same syntax as <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT.html" title="Macro BOOST_SCOPE_EXIT">BOOST_SCOPE_EXIT</a></code> + and <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT_ALL.html" title="Macro BOOST_SCOPE_EXIT_ALL">BOOST_SCOPE_EXIT_ALL</a></code> + respectively. For example (see also <a href="../../../test/same_line.cpp" target="_top"><code class="literal">same_line.cpp</code></a>): + </p> +<p> +</p> +<pre class="programlisting"><span class="preprocessor">#define</span> <span class="identifier">SCOPE_EXIT_INC_DEC</span><span class="special">(</span><span class="identifier">variable</span><span class="special">,</span> <span class="identifier">offset</span><span class="special">)</span> <span class="special">\</span> + <span class="identifier">BOOST_SCOPE_EXIT_ID</span><span class="special">(</span><span class="identifier">BOOST_PP_CAT</span><span class="special">(</span><span class="identifier">inc</span><span class="special">,</span> <span class="identifier">__LINE__</span><span class="special">),</span> <span class="comment">/* unique ID */</span> <span class="special">\</span> + <span class="special">&</span><span class="identifier">variable</span><span class="special">,</span> <span class="identifier">offset</span><span class="special">)</span> <span class="special">{</span> <span class="special">\</span> + <span class="identifier">variable</span> <span class="special">+=</span> <span class="identifier">offset</span><span class="special">;</span> <span class="special">\</span> + <span class="special">}</span> <span class="identifier">BOOST_SCOPE_EXIT_END_ID</span><span class="special">(</span><span class="identifier">BOOST_PP_CAT</span><span class="special">(</span><span class="identifier">inc</span><span class="special">,</span> <span class="identifier">__LINE__</span><span class="special">))</span> <span class="special">\</span> + <span class="special">\</span> + <span class="identifier">BOOST_SCOPE_EXIT_ID</span><span class="special">(</span><span class="identifier">BOOST_PP_CAT</span><span class="special">(</span><span class="identifier">dec</span><span class="special">,</span> <span class="identifier">__LINE__</span><span class="special">),</span> <span class="special">\</span> + <span class="special">&</span><span class="identifier">variable</span><span class="special">,</span> <span class="identifier">offset</span><span class="special">)</span> <span class="special">{</span> <span class="special">\</span> + <span class="identifier">variable</span> <span class="special">-=</span> <span class="identifier">offset</span><span class="special">;</span> <span class="special">\</span> + <span class="special">}</span> <span class="identifier">BOOST_SCOPE_EXIT_END_ID</span><span class="special">(</span><span class="identifier">BOOST_PP_CAT</span><span class="special">(</span><span class="identifier">dec</span><span class="special">,</span> <span class="identifier">__LINE__</span><span class="special">))</span> + +<span class="preprocessor">#define</span> <span class="identifier">SCOPE_EXIT_INC_DEC_TPL</span><span class="special">(</span><span class="identifier">variable</span><span class="special">,</span> <span class="identifier">offset</span><span class="special">)</span> <span class="special">\</span> + <span class="identifier">BOOST_SCOPE_EXIT_TPL_ID</span><span class="special">(</span><span class="identifier">BOOST_PP_CAT</span><span class="special">(</span><span class="identifier">inc</span><span class="special">,</span> <span class="identifier">__LINE__</span><span class="special">),</span> <span class="special">\</span> + <span class="special">&</span><span class="identifier">variable</span><span class="special">,</span> <span class="identifier">offset</span><span class="special">)</span> <span class="special">{</span> <span class="special">\</span> + <span class="identifier">variable</span> <span class="special">+=</span> <span class="identifier">offset</span><span class="special">;</span> <span class="special">\</span> + <span class="special">}</span> <span class="identifier">BOOST_SCOPE_EXIT_END_ID</span><span class="special">(</span><span class="identifier">BOOST_PP_CAT</span><span class="special">(</span><span class="identifier">inc</span><span class="special">,</span> <span class="identifier">__LINE__</span><span class="special">))</span> <span class="special">\</span> + <span class="special">\</span> + <span class="identifier">BOOST_SCOPE_EXIT_TPL_ID</span><span class="special">(</span><span class="identifier">BOOST_PP_CAT</span><span class="special">(</span><span class="identifier">dec</span><span class="special">,</span> <span class="identifier">__LINE__</span><span class="special">),</span> <span class="special">\</span> + <span class="special">&</span><span class="identifier">variable</span><span class="special">,</span> <span class="identifier">offset</span><span class="special">)</span> <span class="special">{</span> <span class="special">\</span> + <span class="identifier">variable</span> <span class="special">-=</span> <span class="identifier">offset</span><span class="special">;</span> <span class="special">\</span> + <span class="special">}</span> <span class="identifier">BOOST_SCOPE_EXIT_END_ID</span><span class="special">(</span><span class="identifier">BOOST_PP_CAT</span><span class="special">(</span><span class="identifier">dec</span><span class="special">,</span> <span class="identifier">__LINE__</span><span class="special">))</span> + +<span class="preprocessor">#define</span> <span class="identifier">SCOPE_EXIT_ALL_INC_DEC</span><span class="special">(</span><span class="identifier">variable</span><span class="special">,</span> <span class="identifier">offset</span><span class="special">)</span> <span class="special">\</span> + <span class="identifier">BOOST_SCOPE_EXIT_ALL_ID</span><span class="special">(</span><span class="identifier">BOOST_PP_CAT</span><span class="special">(</span><span class="identifier">inc</span><span class="special">,</span> <span class="identifier">__LINE__</span><span class="special">),</span> <span class="special">\</span> + <span class="special">=,</span> <span class="special">&</span><span class="identifier">variable</span><span class="special">)</span> <span class="special">{</span> <span class="special">\</span> + <span class="identifier">variable</span> <span class="special">+=</span> <span class="identifier">offset</span><span class="special">;</span> <span class="special">\</span> + <span class="special">};</span> <span class="special">\</span> + <span class="identifier">BOOST_SCOPE_EXIT_ALL_ID</span><span class="special">(</span><span class="identifier">BOOST_PP_CAT</span><span class="special">(</span><span class="identifier">dec</span><span class="special">,</span> <span class="identifier">__LINE__</span><span class="special">),</span> <span class="special">\</span> + <span class="special">=,</span> <span class="special">&</span><span class="identifier">variable</span><span class="special">)</span> <span class="special">{</span> <span class="special">\</span> + <span class="identifier">variable</span> <span class="special">-=</span> <span class="identifier">offset</span><span class="special">;</span> <span class="special">\</span> + <span class="special">};</span> + +<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">T</span><span class="special">></span> +<span class="keyword">void</span> <span class="identifier">f</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">T</span><span class="special">&</span> <span class="identifier">delta</span><span class="special">)</span> <span class="special">{</span> + <span class="identifier">SCOPE_EXIT_INC_DEC_TPL</span><span class="special">(</span><span class="identifier">x</span><span class="special">,</span> <span class="identifier">delta</span><span class="special">)</span> <span class="comment">// Multiple scope exits on same line.</span> + <span class="identifier">BOOST_TEST</span><span class="special">(</span><span class="identifier">x</span> <span class="special">==</span> <span class="number">0</span><span class="special">);</span> +<span class="special">}</span> + +<span class="keyword">int</span> <span class="identifier">main</span><span class="special">(</span><span class="keyword">void</span><span class="special">)</span> <span class="special">{</span> + <span class="keyword">int</span> <span class="identifier">x</span> <span class="special">=</span> <span class="number">0</span><span class="special">,</span> <span class="identifier">delta</span> <span class="special">=</span> <span class="number">10</span><span class="special">;</span> + + <span class="special">{</span> + <span class="identifier">SCOPE_EXIT_INC_DEC</span><span class="special">(</span><span class="identifier">x</span><span class="special">,</span> <span class="identifier">delta</span><span class="special">)</span> <span class="comment">// Multiple scope exits on same line.</span> + <span class="special">}</span> + <span class="identifier">BOOST_TEST</span><span class="special">(</span><span class="identifier">x</span> <span class="special">==</span> <span class="number">0</span><span class="special">);</span> + + <span class="identifier">f</span><span class="special">(</span><span class="identifier">x</span><span class="special">,</span> <span class="identifier">delta</span><span class="special">);</span> + +<span class="preprocessor">#ifndef</span> <span class="identifier">BOOST_NO_LAMBDAS</span> + <span class="special">{</span> + <span class="identifier">SCOPE_EXIT_ALL_INC_DEC</span><span class="special">(</span><span class="identifier">x</span><span class="special">,</span> <span class="identifier">delta</span><span class="special">)</span> <span class="comment">// Multiple scope exits on same line.</span> + <span class="special">}</span> + <span class="identifier">BOOST_TEST</span><span class="special">(</span><span class="identifier">x</span> <span class="special">==</span> <span class="number">0</span><span class="special">);</span> +<span class="preprocessor">#endif</span> <span class="comment">// LAMBDAS</span> + + <span class="keyword">return</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">report_errors</span><span class="special">();</span> +<span class="special">}</span> +</pre> +<p> + </p> +<p> + As shown by the example above, the <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT_ID.html" title="Macro BOOST_SCOPE_EXIT_ID">BOOST_SCOPE_EXIT_ID</a></code>, + <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT_ID_TPL.html" title="Macro BOOST_SCOPE_EXIT_ID_TPL">BOOST_SCOPE_EXIT_ID_TPL</a></code>, + <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT_END_ID.html" title="Macro BOOST_SCOPE_EXIT_END_ID">BOOST_SCOPE_EXIT_END_ID</a></code>, + and <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT_ALL_ID.html" title="Macro BOOST_SCOPE_EXIT_ALL_ID">BOOST_SCOPE_EXIT_ALL_ID</a></code> + macros are especially useful when it is necessary to invoke them multiple + times within user-defined macros (because the C++ preprocessor expands all + nested macros on the same line). + </p> +</div> +<div class="footnotes"> +<br><hr width="100" align="left"> +<div class="footnote"><p><sup>[<a id="ftn.scope_exit.tutorial.capturing_no_variable.f0" href="#scope_exit.tutorial.capturing_no_variable.f0" class="para">3</a>] </sup> + <span class="bold"><strong>Rationale.</strong></span> Unfortunately, it is not possible + to simply invoke the <a class="link" href="../index.html" title="Chapter 1. Boost.ScopeExit 1.1.0">Boost.ScopeExit</a> + macro with no parameters as in <code class="computeroutput"><span class="identifier">BOOST_SCOPE_EXIT</span><span class="special">()</span></code> because the C++ preprocessor cannot detect + emptiness of a macro parameter when the parameter can start with a non-alphanumeric + symbol (which is the case when capturing a variable by reference <code class="computeroutput"><span class="special">&</span><span class="identifier">variable</span></code>). + </p></div> +<div class="footnote"><p><sup>[<a id="ftn.scope_exit.tutorial.capturing_all_variables__c__11_only_.f0" href="#scope_exit.tutorial.capturing_all_variables__c__11_only_.f0" class="para">4</a>] </sup> + <span class="bold"><strong>Rationale.</strong></span> The <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT_ALL.html" title="Macro BOOST_SCOPE_EXIT_ALL">BOOST_SCOPE_EXIT_ALL</a></code> + macro is only defined on C++11 compilers for which the <a href="http://www.boost.org/libs/config" target="_top">Boost.Config</a> + macro <code class="computeroutput"><span class="identifier">BOOST_NO_LAMBDAS</span></code> + is not defined. Using <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT_ALL.html" title="Macro BOOST_SCOPE_EXIT_ALL">BOOST_SCOPE_EXIT_ALL</a></code> + on C++03 compilers for which <code class="computeroutput"><span class="identifier">BOOST_NO_LAMBDAS</span></code> + is defined will generate (possibly cryptic) compiler errors. Note that + a new macro <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT_ALL.html" title="Macro BOOST_SCOPE_EXIT_ALL">BOOST_SCOPE_EXIT_ALL</a></code> + needed to be introduced instead of reusing <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT.html" title="Macro BOOST_SCOPE_EXIT">BOOST_SCOPE_EXIT</a></code> + because <code class="computeroutput"><span class="identifier">BOOST_SCOPE_EXIT</span><span class="special">(&)</span></code> and <code class="computeroutput"><span class="identifier">BOOST_SCOPE_EXIT</span><span class="special">(=)</span></code> cannot be distinguished from <code class="computeroutput"><span class="identifier">BOOST_SCOPE_EXIT</span><span class="special">(</span><span class="keyword">void</span><span class="special">)</span></code> or + <code class="computeroutput"><span class="identifier">BOOST_SCOPE_EXIT</span><span class="special">(</span><span class="identifier">this_</span><span class="special">)</span></code> + using the C++ preprocessor given that the symbols <code class="computeroutput"><span class="special">&</span></code> + and <code class="computeroutput"><span class="special">=</span></code> are neither prefxied + nor postfixed by alphanumeric tokens (this is not an issue for <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT_ALL.html" title="Macro BOOST_SCOPE_EXIT_ALL">BOOST_SCOPE_EXIT_ALL</a></code> which always + has the non-alphanumeric <code class="computeroutput"><span class="special">&</span></code> + or <code class="computeroutput"><span class="special">=</span></code> as the first capture + so the first capture tokens are simply never compared with neither <code class="computeroutput"><span class="keyword">void</span></code> nor <code class="computeroutput"><span class="identifier">this_</span></code> + for this macro). + </p></div> +<div class="footnote"><p><sup>[<a id="ftn.scope_exit.tutorial.capturing_all_variables__c__11_only_.f1" href="#scope_exit.tutorial.capturing_all_variables__c__11_only_.f1" class="para">5</a>] </sup> + At present, there seems to be some discussion to allow C++11 lambda + functions to capture data members without capturing the object <code class="computeroutput"><span class="keyword">this</span></code>. If the C++11 standard were changed + to allow this, the <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT_ALL.html" title="Macro BOOST_SCOPE_EXIT_ALL">BOOST_SCOPE_EXIT_ALL</a></code> + macro syntax could be extended to be a superset of the <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT.html" title="Macro BOOST_SCOPE_EXIT">BOOST_SCOPE_EXIT</a></code> + macro while keeping full backward compatibility. + </p></div> +<div class="footnote"><p><sup>[<a id="ftn.scope_exit.tutorial.capturing_all_variables__c__11_only_.f2" href="#scope_exit.tutorial.capturing_all_variables__c__11_only_.f2" class="para">6</a>] </sup> + On compilers that support the use of the <code class="computeroutput"><span class="keyword">typename</span></code> + outside templates as allowed by the C++11 standard, <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT_ALL.html" title="Macro BOOST_SCOPE_EXIT_ALL">BOOST_SCOPE_EXIT_ALL</a></code> + can use both <code class="computeroutput"><span class="keyword">this</span></code> and + <code class="computeroutput"><span class="identifier">this_</span></code> to capture the + object in scope (notably, this is not the case for the MSVC 10.0 compiler). + </p></div> +<div class="footnote"><p><sup>[<a id="ftn.scope_exit.tutorial.template_workaround__gcc_.f0" href="#scope_exit.tutorial.template_workaround__gcc_.f0" class="para">7</a>] </sup> + <span class="bold"><strong>Rationale.</strong></span> GCC versions compliant with + C++11 do not present this issue and given that <code class="computeroutput"><a class="link" href="../BOOST_SCOPE_EXIT_ALL.html" title="Macro BOOST_SCOPE_EXIT_ALL">BOOST_SCOPE_EXIT_ALL</a></code> + is only available on C++11 compilers, there is no need for a <code class="computeroutput"><span class="identifier">BOOST_SCOPE_EXIT_ALL_TPL</span></code> macro. + </p></div> +<div class="footnote"><p><sup>[<a id="ftn.scope_exit.tutorial.same_line_expansions.f0" href="#scope_exit.tutorial.same_line_expansions.f0" class="para">8</a>] </sup> + <span class="bold"><strong>Rationale.</strong></span> The library macros internally + use <code class="computeroutput"><span class="identifier">__LINE__</span></code> to generate + unique identifiers. Therefore, if the same macro is expanded more than + on time on the same line, the generated identifiers will no longer be unique + and the code will not compile. (This restriction does not apply to MSVC + and other compilers that provide the non-standard <code class="computeroutput"><span class="identifier">__COUNTER__</span></code> + macro.) + </p></div> +<div class="footnote"><p><sup>[<a id="ftn.scope_exit.tutorial.same_line_expansions.f1" href="#scope_exit.tutorial.same_line_expansions.f1" class="para">9</a>] </sup> + Because there are restrictions on the set of tokens that the C++ preprocessor + can concatenate and because not all compilers correctly implement these + restrictions, it is in general recommended to specify unique identifiers + as a combination of alphanumeric tokens. + </p></div> +</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 © 2006 -2009 Alexander Nasonov<p> - Distributed under the Boost Software License, Version 1.0. (See accompanying - file LICENSE_1_0.txt or copy at <ulink url="http://www.boost.org/LICENSE_1_0.txt"> - http://www.boost.org/LICENSE_1_0.txt </ulink>) +<td align="right"><div class="copyright-footer">Copyright © 2006-2012 Alexander Nasonov, Lorenzo Caminiti<p> + Distributed under the Boost Software License, Version 1.0 (see accompanying + file LICENSE_1_0.txt or a copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>) </p> </div></td> </tr></table> <hr> <div class="spirit-nav"> -<a accesskey="p" href="../index.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.html"><img src="../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="alternatives.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a> +<a accesskey="p" href="getting_started.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="alternatives.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a> </div> </body> </html> |