Date: Tue, 14 May 2013 09:02:15 +0200 From: Dimitry Andric <dim@FreeBSD.org> To: Alexander K. Beros <alex@154cm.com> Cc: freebsd-toolchain@freebsd.org Subject: Re: missing some c++11 support for clang in FreeBSD Message-ID: <2DF8523A-A2A9-4915-9EB4-CADFA952DE23@FreeBSD.org> In-Reply-To: <000301ce503a$fb8e8630$f2ab9290$@154cm.com>
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On May 14, 2013, at 02:35, Alexander K. Beros <alex@154cm.com> wrote: > I have just started using clang (on FreeBSD 9.1 AMD64) and encountered a > couple problems. I have worked around these points, but in case they > represent something unintentional (as opposed to some error on my part while > building from the port) I would like to mention them. I am using > > FreeBSD clang version 3.1 (branches/release_31 156863) 20120523 > Target: x86_64-unknown-freebsd9.0 > Thread model: posix > > A key element in solving both problems was the installation of gcc47. That > was unexpected since I initially installed clang under the assumption that > FBSD is moving from gcc to clang and since gcc42 doesn't support c++11. On FreeBSD 9.1, you first need to build libc++, which provides C++11 support. (On 10.0-CURRENT, it is enabled and installed by default, but not on previous releases.) To build and install libc++ on 9.1, add the following lines to /etc/src.conf: CC=clang CXX=clang++ CPP=clang-cpp WITH_LIBCPLUSPLUS=foo Then build and install world in the usual manner. If you prefer to only build libc++ (and its support library, libcxxrt) manually, you can do the following: cd /usr/src/lib/libcxxrt make obj && make depend && make sudo make install cd /usr/src/lib/libc++ make obj && make depend && make sudo make install After libc++ is installed, you still need to tell clang to use it instead of GNU libstdc++; see below. > 1.. > Symptom: > > %> clang++ -std=c++11 -stdlib=libstdc++ refparms.c++ > initListTest.cpp:43:10: fatal error: 'initializer_list' file not > found > #include <initializer_list> > > I had included initializer_list. To enable libc++, you must add the flag -stdlib=libc++ instead. If you use -stdlib=libstdc++, or no -stdlib option, it will use the base system version of GNU libstdc++, which is the version that comes with gcc 4.2, and does not support C++11. > Temporary Solution: > I built gcc47 from the port and then added the following to my > .cshrc file > alias clang11 'clang++ -std=c++11 -I/usr/local/lib/gcc47/include/c++ > -I/usr/local/lib/gcc47/include/c++/x86_64-portbld- freebsd9.1' > > Alternate solution, compile using g++47. This will only work partially, since you still need to make sure to add the proper flags during linking, so clang can find the libstdc++ libraries installed by the gcc47 port. > 2.. > Symptom: > /usr/lib/libstdc++.so.6: version GLIBCXX_3.4.14 required by > /usr/home/../binaries/a.out not found Yes, this is a problem with the gcc ports. They are basically unusable for C++ as-is. Please complain to the maintainer. :-) > Solution: > I added the following line to /etc/libmap.conf > libstdc++.so.6 gcc47/libstdc++.so.6 > > again compiling with g++47 had no such problem. This is a rather brute-force solution, but it should work, since newer versions of libstdc++ are backwards compatible. -Dimitryhome | help
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