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15821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" 25821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) "http://www.w3.org/TR/html4/strict.dtd"> 35821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)<!-- Material used from: HTML 4.01 specs: http://www.w3.org/TR/html401/ --> 45821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)<html> 55821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)<head> 65821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) <META http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> 75821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) <title>"libc++" C++ Standard Library</title> 85821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) <link type="text/css" rel="stylesheet" href="menu.css"> 95821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) <link type="text/css" rel="stylesheet" href="content.css"> 105821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)</head> 115821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 125821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)<body> 135821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)<div id="menu"> 145821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) <div> 155821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) <a href="http://llvm.org/">LLVM Home</a> 165821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) </div> 175821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 185821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) <div class="submenu"> 195821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) <label>libc++ Info</label> 205821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) <a href="/index.html">About</a> 215821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) </div> 225821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 235821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) <div class="submenu"> 245821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) <label>Quick Links</label> 255821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) <a href="http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev">cfe-dev</a> 265821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) <a href="http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits">cfe-commits</a> 275821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) <a href="http://llvm.org/bugs/">Bug Reports</a> 285821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) <a href="http://llvm.org/svn/llvm-project/libcxx/trunk/">Browse SVN</a> 295821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) <a href="http://llvm.org/viewvc/llvm-project/libcxx/trunk/">Browse ViewVC</a> 305821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) </div> 315821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)</div> 325821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 335821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)<div id="content"> 345821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) <!--*********************************************************************--> 355821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) <h1>"libc++" C++ Standard Library</h1> 365821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) <!--*********************************************************************--> 37 38 <p>libc++ is a new implementation of the C++ standard library, targeting 39 C++0X.</p> 40 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> 44 45 <!--=====================================================================--> 46 <h2 id="goals">Features and Goals</h2> 47 <!--=====================================================================--> 48 49 <ul> 50 <li>Correctness as defined by the (currently draft) C++0X standard.</li> 51 <li>Fast execution.</li> 52 <li>Minimal memory use.</li> 53 <li>Fast compile times.</li> 54 <li>ABI compatibility with gcc's libstdc++ for some low-level features 55 such as exception objects, rtti and memory allocation.</li> 56 <li>Extensive unit tests.</li> 57 </ul> 58 59 <!--=====================================================================--> 60 <h2 id="why">Why a new C++ Standard Library for C++'0x?</h2> 61 <!--=====================================================================--> 62 63 <p>After its initial introduction, many people have asked "why start a new 64 library instead of contributing to an existing library?" (like Apache's 65 libstdcxx, GNU's libstdc++, STLport, etc). There are many contributing 66 reasons, but some of the major ones are:</p> 67 68 <ul> 69 <li><p>From years of experience (including having implemented the standard 70 library before), we've learned many things about implementing 71 the standard containers which require ABI breakage and fundamental changes 72 to how they are implemented. For example, it is generally accepted that 73 building std::string using the "short string optimization" instead of 74 using Copy On Write (COW) is a superior approach for multicore 75 machines (particularly in C++'0x, which has rvalue references). Breaking 76 ABI compatibility with old versions of the library was 77 determined to be critical to achieving the performance goals of 78 libc++.</p></li> 79 80 <li><p>Mainline libstdc++ has switched to GPL3, a license which the developers 81 of libc++ cannot use. libstdc++ 4.2 (the last GPL2 version) could be 82 independently extended to support C++'0x, but this would be a fork of the 83 codebase (which is often seen as worse for a project than starting a new 84 independent one). Another problem with libstdc++ is that it is tightly 85 integrated with G++ development, tending to be tied fairly closely to the 86 matching version of G++.</p> 87 </li> 88 89 <li><p>STLport and the Apache libstdcxx library are two other popular 90 candidates, but both lack C++'0x support. Our experience (and the 91 experience of libstdc++ developers) is that adding support for C++0x (in 92 particular rvalue references and move-only types) requires changes to 93 almost every class and function, essentially amounting to a rewrite. 94 Faced with a rewrite, we decided to start from scratch and evaluate every 95 design decision from first principles based on experience.</p> 96 97 <p>Further, both projects are apparently abandoned: STLport 5.2.1 was 98 released in Oct'08, and STDCXX 4.2.1 in May'08.</p> 99 100 </ul> 101 102 <!--=====================================================================--> 103 <h2 id="requirements">Platform Support</h2> 104 <!--=====================================================================--> 105 106 <p>libc++ is known to work on the following platforms, using g++-4.2 and 107 clang (lack of C++0X language support disables some functionality).</p> 108 109 <ul> 110 <li>Mac OS X i386</li> 111 <li>Mac OS X x86_64</li> 112 </ul> 113 114 <!--=====================================================================--> 115 <h2 id="dir-structure">Current Status</h2> 116 <!--=====================================================================--> 117 118 <p>libc++ is still under development. It has about 98% of 119 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2010/n3126.pdf">N3126</a> 120 implemented/tested. C++'98 support is fully featured, and most of C++'0x 121 support is as well. The only major missing piece of C++'0x support is 122 <code><atomic></code>.</p> 123 124 <p><a href="libcxx_by_chapter.pdf">Here</a> is a by-chapter breakdown of what 125 is passing tests and what isn't. This chart is currently based on testing 126 against g++-4.4.0 with -std=c++0x. </p> 127 128 <p> 129 A Windows port is underway. <a href="results.Windows.html">Here</a> are 130 recent test results. 131 </p> 132 133 <!--=====================================================================--> 134 <h2>Get it and get involved!</h2> 135 <!--=====================================================================--> 136 137 <p>To check out the code, use:</p> 138 139 <ul> 140 <li><code>svn co http://llvm.org/svn/llvm-project/libcxx/trunk libcxx</code></li> 141 </ul> 142 143 <p>To build on Mac OS X 10.6, you need a helper library and header 144 <a href="http://home.roadrunner.com/~hinnant/libcppabi.zip">found here</a>. 145 cp cxxabi.h to /usr/include, and cp libc++abi.dylib to /usr/lib. 146 <p> 147 148 <p> 149 Next: 150 </p> 151 152 <ul> 153 <li><code>cd libcxx/lib</code></li> 154 <li><code>export TRIPLE=-apple-</code></li> 155 <li><code>/buildit</code></li> 156 </ul> 157 158 <p> 159 That should result in a libc++.1.dylib. To install it I like to use links 160 instead of copying, but either should work: 161 </p> 162 163 <ul> 164 <li><code>cd /usr/lib</code></li> 165 <li><code>sudo ln -sf path-to-libcxx/lib/libc++.1.dylib libc++.1.dylib</code></li> 166 <li><code>sudo ln -sf libc++.1.dylib libc++.dylib</code></li> 167 <li><code>cd /usr/include/c++</code></li> 168 <li><code>sudo ln -sf path-to-libcxx/include v1</code></li> 169 </ul> 170 171 <p> 172 To use with clang you can: 173 </p> 174 175 <ul> 176 <li><code>clang++ -stdlib=libc++ test.cpp</code></li> 177 <li><code>clang++ -std=c++0x -stdlib=libc++ test.cpp</code></li> 178 </ul> 179 180 <p>To run the libc++ test suit (recommended):</p> 181 182 <ul> 183 <li><code>cd libcxx/test</code></li> 184 <li><code>/testit</code></li> 185 <ul> 186 <li>On Mac OS 10.6, to work around bugs in libc headers like 187 math.h and inttypes.h, add "-U__STRICT_ANSI__" and 188 "-D__STDC_FORMAT_MACROS" to the command line with: 189 <blockquote> 190 <pre>export OPTIONS="-std=c++0x -stdlib=libc++ -U__STRICT_ANSI__ -D__STDC_FORMAT_MACROS"</pre> 191 </blockquote></li> 192 <li>People porting libc++ to other OSes will likely have to 193 define similar macros.</li> 194 </ul> 195 </ul> 196 197 <p>Send discussions to the 198 (<a href="http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev">clang mailing list</a>).</p> 199 200 <!--=====================================================================--> 201 <h2>Design Documents</h2> 202 <!--=====================================================================--> 203 204<ul> 205<li><a href="atomic_design.html"><tt><atomic></tt></a></li> 206<li><a href="type_traits_design.html"><tt><type_traits></tt></a></li> 207</ul> 208 209</div> 210</body> 211</html> 212