mirror of
https://github.com/llvm-mirror/libcxx.git
synced 2025-10-23 10:07:41 +08:00

This patch implements changes to allow _LIBCPP_ASSERT to throw on failure instead of aborting. The main changes needed to do this are: 1. Change _LIBCPP_ASSERT to call a handler via a replacable function pointer instead of calling abort directly. Additionally this patch implements two handler functions, one which aborts and another that throws an exception. 2. Add _NOEXCEPT_DEBUG macro for disabling noexcept spec on function which contain _LIBCPP_ASSERT. This is required in order to prevent assertion failures throwing through a noexcept function. This macro has no effect unless _LIBCPP_DEBUG_USE_EXCEPTIONS is defined. Having a non-aborting _LIBCPP_ASSERT is very important to allow sane testing of debug mode. Currently we can only have one test case per file, since the test case will cause the program to abort. Testing debug mode this way would require thousands of test files, most of which would be 95% boiler plate. I don't think this is a feasible strategy. Fortunately using a throwing debug handler solves these issues. Additionally this patch rewrites the documentation for debug mode. git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@290651 91177308-0d34-0410-b5e6-96231b3b80d8
228 lines
9.6 KiB
HTML
228 lines
9.6 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
|
|
"http://www.w3.org/TR/html4/strict.dtd">
|
|
<!-- Material used from: HTML 4.01 specs: http://www.w3.org/TR/html401/ -->
|
|
<html>
|
|
<head>
|
|
<META http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
|
|
<title>"libc++" C++ Standard Library</title>
|
|
<link type="text/css" rel="stylesheet" href="menu.css">
|
|
<link type="text/css" rel="stylesheet" href="content.css">
|
|
</head>
|
|
|
|
<body>
|
|
<div id="menu">
|
|
<div>
|
|
<a href="http://llvm.org/">LLVM Home</a>
|
|
</div>
|
|
|
|
<div class="submenu">
|
|
<label>libc++ Info</label>
|
|
<a href="/index.html">About</a>
|
|
</div>
|
|
|
|
<div class="submenu">
|
|
<label>Quick Links</label>
|
|
<a href="http://lists.llvm.org/mailman/listinfo/cfe-dev">cfe-dev</a>
|
|
<a href="http://lists.llvm.org/mailman/listinfo/cfe-commits">cfe-commits</a>
|
|
<a href="http://llvm.org/bugs/">Bug Reports</a>
|
|
<a href="http://llvm.org/svn/llvm-project/libcxx/trunk/">Browse SVN</a>
|
|
<a href="http://llvm.org/viewvc/llvm-project/libcxx/trunk/">Browse ViewVC</a>
|
|
</div>
|
|
</div>
|
|
|
|
<div id="content">
|
|
<!--*********************************************************************-->
|
|
<h1>"libc++" C++ Standard Library</h1>
|
|
<!--*********************************************************************-->
|
|
|
|
<p>libc++ is a new implementation of the C++ standard library, targeting
|
|
C++11.</p>
|
|
|
|
<p>All of the code in libc++ is <a
|
|
href="http://llvm.org/docs/DeveloperPolicy.html#license">dual licensed</a>
|
|
under the MIT license and the UIUC License (a BSD-like license).</p>
|
|
|
|
<!--=====================================================================-->
|
|
<h2>New Documentation Coming Soon!</h2>
|
|
<!--=====================================================================-->
|
|
|
|
<p> Looking for documentation on how to use, build and test libc++? If so
|
|
checkout the new libc++ documentation.</p>
|
|
|
|
<p><a href="http://libcxx.llvm.org/docs/">
|
|
Click here for the new libc++ documentation.</a></p>
|
|
|
|
<!--=====================================================================-->
|
|
<h2 id="goals">Features and Goals</h2>
|
|
<!--=====================================================================-->
|
|
|
|
<ul>
|
|
<li>Correctness as defined by the C++11 standard.</li>
|
|
<li>Fast execution.</li>
|
|
<li>Minimal memory use.</li>
|
|
<li>Fast compile times.</li>
|
|
<li>ABI compatibility with gcc's libstdc++ for some low-level features
|
|
such as exception objects, rtti and memory allocation.</li>
|
|
<li>Extensive unit tests.</li>
|
|
</ul>
|
|
|
|
<!--=====================================================================-->
|
|
<h2 id="why">Why a new C++ Standard Library for C++11?</h2>
|
|
<!--=====================================================================-->
|
|
|
|
<p>After its initial introduction, many people have asked "why start a new
|
|
library instead of contributing to an existing library?" (like Apache's
|
|
libstdcxx, GNU's libstdc++, STLport, etc). There are many contributing
|
|
reasons, but some of the major ones are:</p>
|
|
|
|
<ul>
|
|
<li><p>From years of experience (including having implemented the standard
|
|
library before), we've learned many things about implementing
|
|
the standard containers which require ABI breakage and fundamental changes
|
|
to how they are implemented. For example, it is generally accepted that
|
|
building std::string using the "short string optimization" instead of
|
|
using Copy On Write (COW) is a superior approach for multicore
|
|
machines (particularly in C++11, which has rvalue references). Breaking
|
|
ABI compatibility with old versions of the library was
|
|
determined to be critical to achieving the performance goals of
|
|
libc++.</p></li>
|
|
|
|
<li><p>Mainline libstdc++ has switched to GPL3, a license which the developers
|
|
of libc++ cannot use. libstdc++ 4.2 (the last GPL2 version) could be
|
|
independently extended to support C++11, but this would be a fork of the
|
|
codebase (which is often seen as worse for a project than starting a new
|
|
independent one). Another problem with libstdc++ is that it is tightly
|
|
integrated with G++ development, tending to be tied fairly closely to the
|
|
matching version of G++.</p>
|
|
</li>
|
|
|
|
<li><p>STLport and the Apache libstdcxx library are two other popular
|
|
candidates, but both lack C++11 support. Our experience (and the
|
|
experience of libstdc++ developers) is that adding support for C++11 (in
|
|
particular rvalue references and move-only types) requires changes to
|
|
almost every class and function, essentially amounting to a rewrite.
|
|
Faced with a rewrite, we decided to start from scratch and evaluate every
|
|
design decision from first principles based on experience.</p>
|
|
|
|
<p>Further, both projects are apparently abandoned: STLport 5.2.1 was
|
|
released in Oct'08, and STDCXX 4.2.1 in May'08.</p>
|
|
|
|
</ul>
|
|
|
|
<!--=====================================================================-->
|
|
<h2 id="requirements">Platform Support</h2>
|
|
<!--=====================================================================-->
|
|
|
|
<p>
|
|
libc++ is known to work on the following platforms, using g++-4.2 and
|
|
clang (lack of C++11 language support disables some functionality). Note
|
|
that functionality provided by <atomic> is only functional with
|
|
clang.
|
|
</p>
|
|
|
|
<ul>
|
|
<li>Mac OS X i386</li>
|
|
<li>Mac OS X x86_64</li>
|
|
<li>FreeBSD 10+ i386</li>
|
|
<li>FreeBSD 10+ x86_64</li>
|
|
<li>FreeBSD 10+ ARM</li>
|
|
</ul>
|
|
|
|
<!--=====================================================================-->
|
|
<h2 id="dir-structure">Current Status</h2>
|
|
<!--=====================================================================-->
|
|
|
|
<p>libc++ is a 100% complete C++11 implementation on Apple's OS X. </p>
|
|
<p>LLVM and Clang can self host in C++ and C++11 mode with libc++ on Linux.</p>
|
|
<p>libc++ is also a 100% complete C++14 implementation. A list of new features and changes for
|
|
C++14 can be found <a href="cxx1y_status.html">here</a>.</p>
|
|
<p>A list of features and changes for the next C++ standard, known here as
|
|
"C++1z" (probably to be C++17) can be found <a href="cxx1z_status.html">here</a>.</p>
|
|
<p>Implementation of the post-c++14 Technical Specifications is in progress. A list of features and
|
|
the current status of these features can be found <a href="ts1z_status.html">here</a>.</p>
|
|
|
|
<!--======================================================================-->
|
|
<h2 id="buildbots">Build Bots</h2>
|
|
<!--======================================================================-->
|
|
<p>The latest libc++ build results can be found at the following locations.</p>
|
|
<ul>
|
|
<li><a href="http://lab.llvm.org:8011/console">
|
|
Buildbot libc++ builders
|
|
</a></li>
|
|
<li><a href="http://lab.llvm.org:8080/green/view/Libcxx/">
|
|
Jenkins libc++ builders
|
|
</a></li>
|
|
</ul>
|
|
|
|
<!--=====================================================================-->
|
|
<h2>Get it and get involved!</h2>
|
|
<!--=====================================================================-->
|
|
|
|
<p>First please review our
|
|
<a href="http://llvm.org/docs/DeveloperPolicy.html">Developer's Policy</a>.
|
|
|
|
The documentation for building and using libc++ can be found below.
|
|
<ul>
|
|
<li><a href="http://libcxx.llvm.org/docs/UsingLibcxx.html">
|
|
<b>Using libc++</b></a>
|
|
Documentation on using the library in your programs</li>
|
|
<li><a href="http://libcxx.llvm.org/docs/BuildingLibcxx.html">
|
|
<b>Building libc++</b></a>
|
|
Documentation on building the library using CMake</li>
|
|
<li><a href="http://libcxx.llvm.org/docs/TestingLibcxx.html">
|
|
<b>Testing libc++</b></a>
|
|
Documentation for developers wishing to test the library</li>
|
|
</ul>
|
|
|
|
<!--=====================================================================-->
|
|
<h3>Notes and Known Issues</h3>
|
|
<!--=====================================================================-->
|
|
|
|
<p>
|
|
<ul>
|
|
<li>
|
|
Building libc++ with <code>-fno-rtti</code> is not supported. However
|
|
linking against it with <code>-fno-rtti</code> is supported.
|
|
</li>
|
|
<li>
|
|
On OS X v10.8 and older the CMake option
|
|
<code>-DLIBCXX_LIBCPPABI_VERSION=""</code> must be used during
|
|
configuration.
|
|
</li>
|
|
</ul>
|
|
</p>
|
|
|
|
<p>Send discussions to the
|
|
<a href="http://lists.llvm.org/mailman/listinfo/cfe-dev">clang mailing list</a>.</p>
|
|
|
|
<!--=====================================================================-->
|
|
<h2>Bug reports and patches</h2>
|
|
<!--=====================================================================-->
|
|
|
|
<p>
|
|
If you think you've found a bug in libc++, please report it using
|
|
the <a href="http://llvm.org/bugs">LLVM Bugzilla</a>. If you're not sure, you
|
|
can post a message to the <a href="http://lists.llvm.org/mailman/listinfo/cfe-dev">cfe-dev</a>
|
|
mailing list or on IRC. Please include "libc++" in your subject.
|
|
</p>
|
|
|
|
<p>
|
|
If you want to contribute a patch to libc++, the best place for that is
|
|
<a href="http://llvm.org/docs/Phabricator.html">Phabricator</a>. Please
|
|
include [libc++] in the subject and add cfe-commits as a subscriber.
|
|
</p>
|
|
|
|
<!--=====================================================================-->
|
|
<h2>Design Documents</h2>
|
|
<!--=====================================================================-->
|
|
|
|
<ul>
|
|
<li><a href="atomic_design.html"><tt><atomic></tt></a></li>
|
|
<li><a href="type_traits_design.html"><tt><type_traits></tt></a></li>
|
|
<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>
|
|
</ul>
|
|
|
|
</div>
|
|
</body>
|
|
</html>
|