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Howard Hinnantd2bb0322010-08-22 01:04:38 +0000[diff] [blame]17
Howard Hinnantbc8d3f92010-05-11 19:42:16 +0000[diff] [blame]18 <div class="submenu">
19 <label>libc++ Info</label>
20 <a href="/index.html">About</a>
21 </div>
22
23 <div class="submenu">
24 <label>Quick Links</label>
Tanya Lattnerd08dbfc2015-08-05 03:59:14 +0000[diff] [blame]25 <a href="http://lists.llvm.org/mailman/listinfo/cfe-dev">cfe-dev</a>
26 <a href="http://lists.llvm.org/mailman/listinfo/cfe-commits">cfe-commits</a>
Eric Fiselierb7fd0be2017-02-17 08:37:03 +0000[diff] [blame^]27 <a href="https://bugs.llvm.org/">Bug Reports</a>
Howard Hinnant76e1ffc2010-05-11 20:51:20 +0000[diff] [blame]28 <a href="http://llvm.org/svn/llvm-project/libcxx/trunk/">Browse SVN</a>
29 <a href="http://llvm.org/viewvc/llvm-project/libcxx/trunk/">Browse ViewVC</a>
Howard Hinnantbc8d3f92010-05-11 19:42:16 +0000[diff] [blame]30 </div>
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33<div id="content">
34 <!--*********************************************************************-->
35 <h1>"libc++" C++ Standard Library</h1>
36 <!--*********************************************************************-->
Howard Hinnantd2bb0322010-08-22 01:04:38 +0000[diff] [blame]37
Howard Hinnantbc8d3f92010-05-11 19:42:16 +0000[diff] [blame]38 <p>libc++ is a new implementation of the C++ standard library, targeting
Howard Hinnantaf347342012-07-19 15:57:51 +0000[diff] [blame]39 C++11.</p>
Howard Hinnantbc8d3f92010-05-11 19:42:16 +0000[diff] [blame]40
Chris Lattnerf38bc6e2010-11-16 21:40:19 +0000[diff] [blame]41 <p>All of the code in libc++ is <a
42 href="http://llvm.org/docs/DeveloperPolicy.html#license">dual licensed</a>
43 under the MIT license and the UIUC License (a BSD-like license).</p>
Howard Hinnantd2bb0322010-08-22 01:04:38 +0000[diff] [blame]44
Howard Hinnantbc8d3f92010-05-11 19:42:16 +0000[diff] [blame]45 <!--=====================================================================-->
Eric Fiselierd1e2a832015-10-14 20:51:33 +0000[diff] [blame]46 <h2>New Documentation Coming Soon!</h2>
47 <!--=====================================================================-->
48
49 <p> Looking for documentation on how to use, build and test libc++? If so
50 checkout the new libc++ documentation.</p>
51
52 <p><a href="http://libcxx.llvm.org/docs/">
53 Click here for the new libc++ documentation.</a></p>
54
55 <!--=====================================================================-->
Howard Hinnantbc8d3f92010-05-11 19:42:16 +0000[diff] [blame]56 <h2 id="goals">Features and Goals</h2>
57 <!--=====================================================================-->
Howard Hinnantd2bb0322010-08-22 01:04:38 +0000[diff] [blame]58
Howard Hinnantbc8d3f92010-05-11 19:42:16 +0000[diff] [blame]59 <ul>
Howard Hinnantaf347342012-07-19 15:57:51 +0000[diff] [blame]60 <li>Correctness as defined by the C++11 standard.</li>
Howard Hinnantbc8d3f92010-05-11 19:42:16 +0000[diff] [blame]61 <li>Fast execution.</li>
62 <li>Minimal memory use.</li>
63 <li>Fast compile times.</li>
64 <li>ABI compatibility with gcc's libstdc++ for some low-level features
65 such as exception objects, rtti and memory allocation.</li>
66 <li>Extensive unit tests.</li>
67 </ul>
68
69 <!--=====================================================================-->
Marshall Clowfaa17162012-11-14 16:31:15 +0000[diff] [blame]70 <h2 id="why">Why a new C++ Standard Library for C++11?</h2>
Chris Lattner24173b82010-05-12 22:21:15 +0000[diff] [blame]71 <!--=====================================================================-->
Howard Hinnantd2bb0322010-08-22 01:04:38 +0000[diff] [blame]72
Chris Lattner24173b82010-05-12 22:21:15 +0000[diff] [blame]73 <p>After its initial introduction, many people have asked "why start a new
74 library instead of contributing to an existing library?" (like Apache's
75 libstdcxx, GNU's libstdc++, STLport, etc). There are many contributing
76 reasons, but some of the major ones are:</p>
Howard Hinnantd2bb0322010-08-22 01:04:38 +0000[diff] [blame]77
Chris Lattner24173b82010-05-12 22:21:15 +0000[diff] [blame]78 <ul>
79 <li><p>From years of experience (including having implemented the standard
80 library before), we've learned many things about implementing
81 the standard containers which require ABI breakage and fundamental changes
82 to how they are implemented. For example, it is generally accepted that
83 building std::string using the "short string optimization" instead of
84 using Copy On Write (COW) is a superior approach for multicore
Marshall Clowfaa17162012-11-14 16:31:15 +0000[diff] [blame]85 machines (particularly in C++11, which has rvalue references). Breaking
Chris Lattnera5058d92010-05-12 22:30:22 +0000[diff] [blame]86 ABI compatibility with old versions of the library was
Chris Lattner24173b82010-05-12 22:21:15 +0000[diff] [blame]87 determined to be critical to achieving the performance goals of
88 libc++.</p></li>
Howard Hinnantd2bb0322010-08-22 01:04:38 +0000[diff] [blame]89
Chris Lattner24173b82010-05-12 22:21:15 +0000[diff] [blame]90 <li><p>Mainline libstdc++ has switched to GPL3, a license which the developers
91 of libc++ cannot use. libstdc++ 4.2 (the last GPL2 version) could be
Marshall Clowfaa17162012-11-14 16:31:15 +0000[diff] [blame]92 independently extended to support C++11, but this would be a fork of the
Chris Lattnerf3382492010-05-12 22:33:00 +0000[diff] [blame]93 codebase (which is often seen as worse for a project than starting a new
94 independent one). Another problem with libstdc++ is that it is tightly
95 integrated with G++ development, tending to be tied fairly closely to the
96 matching version of G++.</p>
Chris Lattner24173b82010-05-12 22:21:15 +0000[diff] [blame]97 </li>
98
99 <li><p>STLport and the Apache libstdcxx library are two other popular
Marshall Clowfaa17162012-11-14 16:31:15 +0000[diff] [blame]100 candidates, but both lack C++11 support. Our experience (and the
Howard Hinnantaf347342012-07-19 15:57:51 +0000[diff] [blame]101 experience of libstdc++ developers) is that adding support for C++11 (in
Chris Lattner24173b82010-05-12 22:21:15 +0000[diff] [blame]102 particular rvalue references and move-only types) requires changes to
103 almost every class and function, essentially amounting to a rewrite.
Chris Lattnerbfa808e2010-05-12 22:34:21 +0000[diff] [blame]104 Faced with a rewrite, we decided to start from scratch and evaluate every
105 design decision from first principles based on experience.</p>
Howard Hinnantd2bb0322010-08-22 01:04:38 +0000[diff] [blame]106
Chris Lattner24173b82010-05-12 22:21:15 +0000[diff] [blame]107 <p>Further, both projects are apparently abandoned: STLport 5.2.1 was
108 released in Oct'08, and STDCXX 4.2.1 in May'08.</p>
109
110 </ul>
111
112 <!--=====================================================================-->
Howard Hinnantbc8d3f92010-05-11 19:42:16 +0000[diff] [blame]113 <h2 id="requirements">Platform Support</h2>
114 <!--=====================================================================-->
115
Dan Albert35d775d2014-08-11 15:12:46 +0000[diff] [blame]116 <p>
117 libc++ is known to work on the following platforms, using g++-4.2 and
118 clang (lack of C++11 language support disables some functionality). Note
119 that functionality provided by &lt;atomic&gt; is only functional with
120 clang.
121 </p>
Howard Hinnantbc8d3f92010-05-11 19:42:16 +0000[diff] [blame]122
Dan Albert35d775d2014-08-11 15:12:46 +0000[diff] [blame]123 <ul>
124 <li>Mac OS X i386</li>
125 <li>Mac OS X x86_64</li>
126 <li>FreeBSD 10+ i386</li>
127 <li>FreeBSD 10+ x86_64</li>
128 <li>FreeBSD 10+ ARM</li>
129 </ul>
Howard Hinnantbc8d3f92010-05-11 19:42:16 +0000[diff] [blame]130
131 <!--=====================================================================-->
132 <h2 id="dir-structure">Current Status</h2>
133 <!--=====================================================================-->
134
Howard Hinnantb0895ff2012-11-27 18:52:32 +0000[diff] [blame]135 <p>libc++ is a 100% complete C++11 implementation on Apple's OS X. </p>
Michael J. Spencerdb8a0302012-12-31 19:34:21 +0000[diff] [blame]136 <p>LLVM and Clang can self host in C++ and C++11 mode with libc++ on Linux.</p>
Dan Alberte3eda9d2015-01-30 22:33:41 +0000[diff] [blame]137 <p>libc++ is also a 100% complete C++14 implementation. A list of new features and changes for
Marshall Clowe4915d92014-04-03 02:35:29 +0000[diff] [blame]138 C++14 can be found <a href="cxx1y_status.html">here</a>.</p>
Marshall Clow1e895c12014-11-10 15:43:20 +0000[diff] [blame]139 <p>A list of features and changes for the next C++ standard, known here as
140 "C++1z" (probably to be C++17) can be found <a href="cxx1z_status.html">here</a>.</p>
Marshall Clowd2f0b5c2014-06-02 23:37:13 +0000[diff] [blame]141 <p>Implementation of the post-c++14 Technical Specifications is in progress. A list of features and
142 the current status of these features can be found <a href="ts1z_status.html">here</a>.</p>
Howard Hinnant0cbb3a12011-09-28 15:44:39 +0000[diff] [blame]143
Eric Fiseliercaf1c022014-08-18 05:25:04 +0000[diff] [blame]144 <!--======================================================================-->
Dan Alberte3eda9d2015-01-30 22:33:41 +0000[diff] [blame]145 <h2 id="buildbots">Build Bots</h2>
Eric Fiseliercaf1c022014-08-18 05:25:04 +0000[diff] [blame]146 <!--======================================================================-->
Eric Fiselier453a5002014-12-09 22:53:21 +0000[diff] [blame]147 <p>The latest libc++ build results can be found at the following locations.</p>
Eric Fiseliercaf1c022014-08-18 05:25:04 +0000[diff] [blame]148 <ul>
Eric Fiselier453a5002014-12-09 22:53:21 +0000[diff] [blame]149 <li><a href="http://lab.llvm.org:8011/console">
150 Buildbot libc++ builders
Eric Fiseliercaf1c022014-08-18 05:25:04 +0000[diff] [blame]151 </a></li>
Eric Fiselier453a5002014-12-09 22:53:21 +0000[diff] [blame]152 <li><a href="http://lab.llvm.org:8080/green/view/Libcxx/">
153 Jenkins libc++ builders
Eric Fiseliera43d1142014-10-16 02:48:59 +0000[diff] [blame]154 </a></li>
Eric Fiseliercaf1c022014-08-18 05:25:04 +0000[diff] [blame]155 </ul>
156
Howard Hinnantbc8d3f92010-05-11 19:42:16 +0000[diff] [blame]157 <!--=====================================================================-->
158 <h2>Get it and get involved!</h2>
159 <!--=====================================================================-->
Howard Hinnantd2bb0322010-08-22 01:04:38 +0000[diff] [blame]160
Howard Hinnant2481cba2011-09-30 16:58:02 +0000[diff] [blame]161 <p>First please review our
162 <a href="http://llvm.org/docs/DeveloperPolicy.html">Developer's Policy</a>.
163
Eric Fiselierd2562802016-06-02 02:16:28 +0000[diff] [blame]164 The documentation for building and using libc++ can be found below.
165 <ul>
166 <li><a href="http://libcxx.llvm.org/docs/UsingLibcxx.html">
167 <b>Using libc++</b></a>
168 Documentation on using the library in your programs</li>
169 <li><a href="http://libcxx.llvm.org/docs/BuildingLibcxx.html">
170 <b>Building libc++</b></a>
171 Documentation on building the library using CMake</li>
172 <li><a href="http://libcxx.llvm.org/docs/TestingLibcxx.html">
173 <b>Testing libc++</b></a>
174 Documentation for developers wishing to test the library</li>
175 </ul>
Dan Albert35d775d2014-08-11 15:12:46 +0000[diff] [blame]176
177 <!--=====================================================================-->
Eric Fiseliera5ad9ac2015-05-12 22:55:30 +0000[diff] [blame]178 <h3>Notes and Known Issues</h3>
Dan Albert35d775d2014-08-11 15:12:46 +0000[diff] [blame]179 <!--=====================================================================-->
180
181 <p>
Eric Fiseliera5ad9ac2015-05-12 22:55:30 +0000[diff] [blame]182 <ul>
183 <li>
184 Building libc++ with <code>-fno-rtti</code> is not supported. However
185 linking against it with <code>-fno-rtti</code> is supported.
186 </li>
187 <li>
188 On OS X v10.8 and older the CMake option
189 <code>-DLIBCXX_LIBCPPABI_VERSION=""</code> must be used during
190 configuration.
191 </li>
192 </ul>
Dan Albert35d775d2014-08-11 15:12:46 +0000[diff] [blame]193 </p>
194
195 <p>Send discussions to the
Tanya Lattnerd08dbfc2015-08-05 03:59:14 +0000[diff] [blame]196 <a href="http://lists.llvm.org/mailman/listinfo/cfe-dev">clang mailing list</a>.</p>
Dan Albert35d775d2014-08-11 15:12:46 +0000[diff] [blame]197
198 <!--=====================================================================-->
Marshall Clow992f9d52014-04-03 03:13:12 +0000[diff] [blame]199 <h2>Bug reports and patches</h2>
200 <!--=====================================================================-->
201
Dan Alberte3eda9d2015-01-30 22:33:41 +0000[diff] [blame]202 <p>
203 If you think you've found a bug in libc++, please report it using
204 the <a href="http://llvm.org/bugs">LLVM Bugzilla</a>. If you're not sure, you
Tanya Lattnerd08dbfc2015-08-05 03:59:14 +0000[diff] [blame]205 can post a message to the <a href="http://lists.llvm.org/mailman/listinfo/cfe-dev">cfe-dev</a>
Dan Alberte3eda9d2015-01-30 22:33:41 +0000[diff] [blame]206 mailing list or on IRC. Please include "libc++" in your subject.
207 </p>
Marshall Clow992f9d52014-04-03 03:13:12 +0000[diff] [blame]208
Dan Alberte3eda9d2015-01-30 22:33:41 +0000[diff] [blame]209 <p>
210 If you want to contribute a patch to libc++, the best place for that is
211 <a href="http://llvm.org/docs/Phabricator.html">Phabricator</a>. Please
212 include [libc++] in the subject and add cfe-commits as a subscriber.
213 </p>
Marshall Clow992f9d52014-04-03 03:13:12 +0000[diff] [blame]214
215 <!--=====================================================================-->
Howard Hinnant56f0d5b2010-10-05 16:44:40 +0000[diff] [blame]216 <h2>Design Documents</h2>
217 <!--=====================================================================-->
218
219<ul>
220<li><a href="atomic_design.html"><tt>&lt;atomic&gt;</tt></a></li>
Howard Hinnant9835d762010-11-19 01:38:58 +0000[diff] [blame]221<li><a href="type_traits_design.html"><tt>&lt;type_traits&gt;</tt></a></li>
Marshall Clowe47bc9b2013-03-14 19:00:34 +0000[diff] [blame]222<li><a href="http://cplusplusmusings.wordpress.com/2012/07/05/clang-and-standard-libraries-on-mac-os-x/">Excellent notes by Marshall Clow</a></li>
Howard Hinnant56f0d5b2010-10-05 16:44:40 +0000[diff] [blame]223</ul>
224
Howard Hinnantbc8d3f92010-05-11 19:42:16 +0000[diff] [blame]225</div>
226</body>
Chris Lattner4b748952010-05-11 20:37:52 +0000[diff] [blame]227</html>