<html xmlns="http://www.w3.org/1999/xhtml"><head><title>Chapter 30. Concurrency</title><meta name="generator" content="DocBook XSL-NS Stylesheets V1.76.1"/><meta name="keywords" content=" ISO C++ , library "/><meta name="keywords" content=" ISO C++ , library "/><meta name="keywords" content=" ISO C++ , runtime , library "/><link rel="home" href="../index.html" title="The GNU C++ Library"/><link rel="up" href="extensions.html" title="Part III. Extensions"/><link rel="prev" href="ext_demangling.html" title="Chapter 29. Demangling"/><link rel="next" href="bk01pt03ch30s02.html" title="Implementation"/></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Chapter 30. Concurrency</th></tr><tr><td align="left"><a accesskey="p" href="ext_demangling.html">Prev</a> </td><th width="60%" align="center">Part III.
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-</th><td align="right"> <a accesskey="n" href="bk01pt03ch30s02.html">Next</a></td></tr></table><hr/></div><div class="chapter" title="Chapter 30. Concurrency"><div class="titlepage"><div><div><h2 class="title"><a id="manual.ext.concurrency"/>Chapter 30. Concurrency</h2></div></div></div><div class="toc"><p><strong>Table of Contents</strong></p><dl><dt><span class="section"><a href="ext_concurrency.html#manual.ext.concurrency.design">Design</a></span></dt><dd><dl><dt><span class="section"><a href="ext_concurrency.html#manual.ext.concurrency.design.threads">Interface to Locks and Mutexes</a></span></dt><dt><span class="section"><a href="ext_concurrency.html#manual.ext.concurrency.design.atomics">Interface to Atomic Functions</a></span></dt></dl></dd><dt><span class="section"><a href="bk01pt03ch30s02.html">Implementation</a></span></dt><dd><dl><dt><span class="section"><a href="bk01pt03ch30s02.html#manual.ext.concurrency.impl.atomic_fallbacks">Using Builtin Atomic Functions</a></span></dt><dt><span class="section"><a href="bk01pt03ch30s02.html#manual.ext.concurrency.impl.thread">Thread Abstraction</a></span></dt></dl></dd><dt><span class="section"><a href="bk01pt03ch30s03.html">Use</a></span></dt></dl></div><div class="section" title="Design"><div class="titlepage"><div><div><h2 class="title"><a id="manual.ext.concurrency.design"/>Design</h2></div></div></div><div class="section" title="Interface to Locks and Mutexes"><div class="titlepage"><div><div><h3 class="title"><a id="manual.ext.concurrency.design.threads"/>Interface to Locks and Mutexes</h3></div></div></div><p>The file <ext/concurrence.h> contains all the higher-level
+</th><td align="right"> <a accesskey="n" href="bk01pt03ch30s02.html">Next</a></td></tr></table><hr/></div><div class="chapter" title="Chapter 30. Concurrency"><div class="titlepage"><div><div><h2 class="title"><a id="manual.ext.concurrency"/>Chapter 30. Concurrency</h2></div></div></div><div class="toc"><p><strong>Table of Contents</strong></p><dl><dt><span class="section"><a href="ext_concurrency.html#manual.ext.concurrency.design">Design</a></span></dt><dd><dl><dt><span class="section"><a href="ext_concurrency.html#manual.ext.concurrency.design.threads">Interface to Locks and Mutexes</a></span></dt><dt><span class="section"><a href="ext_concurrency.html#manual.ext.concurrency.design.atomics">Interface to Atomic Functions</a></span></dt></dl></dd><dt><span class="section"><a href="bk01pt03ch30s02.html">Implementation</a></span></dt><dd><dl><dt><span class="section"><a href="bk01pt03ch30s02.html#manual.ext.concurrency.impl.atomic_fallbacks">Using Builtin Atomic Functions</a></span></dt><dt><span class="section"><a href="bk01pt03ch30s02.html#manual.ext.concurrency.impl.thread">Thread Abstraction</a></span></dt></dl></dd><dt><span class="section"><a href="bk01pt03ch30s03.html">Use</a></span></dt></dl></div><div class="section" title="Design"><div class="titlepage"><div><div><h2 class="title"><a id="manual.ext.concurrency.design"/>Design</h2></div></div></div><div class="section" title="Interface to Locks and Mutexes"><div class="titlepage"><div><div><h3 class="title"><a id="manual.ext.concurrency.design.threads"/>Interface to Locks and Mutexes</h3></div></div></div><p>The file <code class="filename"><ext/concurrence.h></code>
+contains all the higher-level
constructs for playing with threads. In contrast to the atomics layer,
the concurrence layer consists largely of types. All types are defined within <code class="code">namespace __gnu_cxx</code>.
</p><p>
host environment and the current compilation flags.
</p><p>Two more datatypes make up the rest of the
interface: <code class="code">__mutex</code>, and <code class="code">__scoped_lock</code>.
-</p><p>
</p><p>The scoped lock idiom is well-discussed within the C++
community. This version takes a <code class="code">__mutex</code> reference, and
-locks it during construction of <code class="code">__scoped_locke</code> and
+locks it during construction of <code class="code">__scoped_lock</code> and
unlocks it during destruction. This is an efficient way of locking
critical sections, while retaining exception-safety.
+These types have been superseded in the ISO C++ 2011 standard by the
+mutex and lock types defined in the header
+<code class="filename"><mutex></code>.
</p></div><div class="section" title="Interface to Atomic Functions"><div class="titlepage"><div><div><h3 class="title"><a id="manual.ext.concurrency.design.atomics"/>Interface to Atomic Functions</h3></div></div></div><p>
Two functions and one type form the base of atomic support.
</p><p>The type <code class="code">_Atomic_word</code> is a signed integral type