1 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" 2 "http://www.w3.org/TR/html4/strict.dtd"> 3 <!-- Material used from: HTML 4.01 specs: http://www.w3.org/TR/html401/ --> 4 <html> 5 <head> 6 <META http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> 7 <title>"libc++abi" C++ Standard Library Support</title> 8 <link type="text/css" rel="stylesheet" href="menu.css"> 9 <link type="text/css" rel="stylesheet" href="content.css"> 10 </head> 11 12 <body> 13 <div id="menu"> 14 <div> 15 <a href="http://llvm.org/">LLVM Home</a> 16 </div> 17 18 <div class="submenu"> 19 <label>libc++abi Info</label> 20 <a href="/index.html">About</a> 21 </div> 22 23 <div class="submenu"> 24 <label>Quick Links</label> 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> 27 <a href="http://llvm.org/bugs/">Bug Reports</a> 28 <a href="http://llvm.org/svn/llvm-project/libcxxabi/trunk/">Browse SVN</a> 29 <a href="http://llvm.org/viewvc/llvm-project/libcxxabi/trunk/">Browse ViewVC</a> 30 </div> 31 </div> 32 33 <div id="content"> 34 <!--*********************************************************************--> 35 <h1>"libc++abi" C++ Standard Library Support</h1> 36 <!--*********************************************************************--> 37 38 <p>libc++abi is a new implementation of low level support for a standard 39 C++ library.</p> 40 41 <p>All of the code in libc++abi 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 C++11 standard.</li> 51 <li>Provide a portable sublayer to ease the porting of <a href="http://libcxx.llvm.org/">libc++</a></li> 52 <li>On Mac OS X, be ABI compatible with the existing low-level support.</li> 53 </ul> 54 55 <!--=====================================================================--> 56 <h2 id="requirements">Platform Support</h2> 57 <!--=====================================================================--> 58 59 <p>libc++abi is known to work on the following platforms, using clang.</p> 60 61 <ul> 62 <li>Darwin</li> 63 </ul> 64 65 <!--=====================================================================--> 66 <h2 id="dir-structure">Current Status</h2> 67 <!--=====================================================================--> 68 69 <p>libc++abi is complete. <a href="spec.html">Here</a> is a 70 list of functionality.</p> 71 72 <!--=====================================================================--> 73 <h2>Get it and get involved!</h2> 74 <!--=====================================================================--> 75 76 <p>To check out the code, use:</p> 77 78 <ul> 79 <li><code>svn co http://llvm.org/svn/llvm-project/libcxxabi/trunk libcxxabi</code></li> 80 </ul> 81 82 <p>To build:</p> 83 <ul> 84 <li>Check out libcxxabi into <code>llvm/projects</code></li> 85 <li><code>cd llvm</code></li> 86 <li><code>mkdir build && cd build</code></li> 87 <li><code>cmake .. # on linux you may need to prefix with CC=clang CXX=clang++</code></li> 88 <li><code>make</code></li> 89 </ul> 90 91 <p>To do a standalone build:</p> 92 <ul> 93 <li> 94 Check out the <a href="http://libcxx.llvm.org">libcxx source</a> tree. 95 </li> 96 <li><code>cd libcxxabi</code></li> 97 <li><code>mkdir build && cd build</code></li> 98 <li><code>cmake -DLIBCXXABI_LIBCXX_PATH=path/to/libcxx .. # on 99 linux you may need -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++</code></li> 100 <li><code>make</code></li> 101 </ul> 102 <p> By default CMake uses <code>llvm-config</code> to locate the required 103 LLVM sources. If CMake cannot find <code>llvm-config</code> then you must 104 configure CMake using either of the following options. 105 </p> 106 <ul> 107 <li><code>-DLLVM_CONFIG_PATH=path/to/llvm-config</code></li> 108 <li><code>-DLLVM_PATH=path/to/llvm-source-root</code></li> 109 </ul> 110 111 </p> 112 113 <p>To run the tests:</p> 114 <ul> 115 <li><code>make check-cxxabi</code></li> 116 </ul> 117 <p>Note: in a standalone build, the system's libc++ will be used for tests. If 118 the system's libc++ was statically linked against libc++abi (or linked against 119 a different ABI library), this may interfere with test results.</p> 120 121 <p>Send discussions to the 122 (<a href="http://lists.llvm.org/mailman/listinfo/cfe-dev">clang mailing list</a>).</p> 123 124 <!--=====================================================================--> 125 <h2>Frequently asked questions</h2> 126 <!--=====================================================================--> 127 128 <p>Q: Why are the destructors for the standard exception classes defined in libc++abi? 129 They're just empty, can't they be defined inline?</p> 130 <p>A: The destructors for them live in libc++abi because they are "key" functions. 131 The Itanium ABI describes a "key" function as the first virtual declared. 132 And wherever the key function is defined, that is where the <code>type_info</code> gets defined. 133 And in libc++ types are the same type if and only if they have the same <code>type_info</code> 134 (as in there must be only one type info per type in the entire application). 135 And on OS X, libstdc++ and libc++ share these exception types. 136 So to be able to throw in one dylib and catch in another (a <code>std::exception</code> for example), 137 there must be only one <code>std::exception type_info</code> in the entire app. 138 That typeinfo gets laid down beside <code>~exception()</code> in libc++abi (for both libstdc++ and libc++).</p> 139 <p>--Howard Hinnant</p> 140 141 </div> 142 </body> 143 </html> 144
