diff options
Diffstat (limited to '2014-10-26-gcc_4_7_introduced_new_c++11_abi/2014-10-26-gcc_4_7_introduced_new_c++11_abi.en.txt')
| -rw-r--r-- | 2014-10-26-gcc_4_7_introduced_new_c++11_abi/2014-10-26-gcc_4_7_introduced_new_c++11_abi.en.txt | 50 |
1 files changed, 50 insertions, 0 deletions
diff --git a/2014-10-26-gcc_4_7_introduced_new_c++11_abi/2014-10-26-gcc_4_7_introduced_new_c++11_abi.en.txt b/2014-10-26-gcc_4_7_introduced_new_c++11_abi/2014-10-26-gcc_4_7_introduced_new_c++11_abi.en.txt new file mode 100644 index 0000000..d074dbe --- /dev/null +++ b/2014-10-26-gcc_4_7_introduced_new_c++11_abi/2014-10-26-gcc_4_7_introduced_new_c++11_abi.en.txt @@ -0,0 +1,50 @@ +Title: GCC 4.7 Introduced the New C++11 ABI +Author: Anthony G. Basile <blueness@gentoo.org> +Content-Type: text/plain +Posted: 2014-10-26 +Revision: 1 +News-Item-Format: 1.0 +Display-If-Installed: >=sys-devel/gcc-4.7.0 +Display-If-Keyword: amd64 +Display-If-Keyword: arm +Display-If-Keyword: mips +Display-If-Keyword: ppc +Display-If-Keyword: ppc64 +Display-If-Keyword: x86 +Display-If-Keyword: amd64-fbsd +Display-If-Keyword: x86-fbsd + +GCC 4.7 introduced the new experimental 2011 ISO C++ standard [1], along with +its GNU variant. This new standard is not the default in gcc-4.7, 4.8 or 4.9, +the default is still gnu++98, but it can be enabled by passing -std=c++11 or +-std=gnu++11 to CXXFLAGS. + +Users that wish to try C++11 should exercise caution because it is not +ABI-compatible with C++98. Nor is C++11 code compiled with gcc-4.7 guaranteed +to be ABI-compatible with C++11 compiled with 4.8, or vice versa [2]. Thus +linking C++98 and C++11, or C++11 compiled with different versions of gcc, is +likely to cause breakage. For packages which are self-contained or do not link +against any libraries written in C++, there is no problem. However, switching +to C++11 and then building packages which link against any of the numerous +libraries in an incompatible ABI can lead to a broken system. + +This is a precautionary news item and the typical user need not do anything. +However, as C++11 gains in popularity and the number of packages using it +increases, it is important that users understand these issues [3]. + +For an ABI compliance checker, and more information about C++ ABIs, see [4]. + +Ref. + +[1] http://www.stroustrup.com/C++11FAQ.html + +[2] Upstream GCC does not support ABI-compatibility between gcc-4.x and 4.y for +any x != y . See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61758. Even +having different versions of gcc installed simultaneously may lead to problems, +especially if the older version of gcc is active. An example is +https://bugs.gentoo.org/show_bug.cgi?id=513386. + +[3] Note that some packages like www-client/chromium and net-libs/webkit-gtk +are already using C++11 features. + +[4] http://ispras.linuxbase.org/index.php/ABI_compliance_checker |