xcode 找不到 omp.h，OS X Yosemite 没有使用最新的 gcc 版本
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omp.h not found, OS X Yosemite not using newest gcc version
提问by Stephanie Embgen
I am trying to build GraphChi on OS X Yosemite but get the following error:
我正在尝试在 OS X Yosemite 上构建 GraphChi，但出现以下错误：
fatal error: 'omp.h' file not found
fatal error: 'omp.h' file not found
From this question - How to include omp.h in OS X?- I learned that Yosemite uses Clang instead of gcc, which does not include omp.h.
从这个问题 -如何在 OS X 中包含 omp.h？- 我了解到 Yosemite 使用 Clang 而不是 gcc，后者不包括 omp.h。
$ which gcc
/usr/bin/gcc
$ gcc -v
Configured with: --prefix=/Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-dir=/usr/include/c++/4.2.1
Apple LLVM version 6.0 (clang-600.0.56) (based on LLVM 3.5svn)
Target: x86_64-apple-darwin14.1.0
Thread model: posix
Next, I installed gcc via Homebrew
接下来，我通过 Homebrew 安装了 gcc
$ brew info gcc
gcc: stable 4.9.2 (bottled)
http://gcc.gnu.org
/usr/local/Cellar/gcc/4.9.2_1 (1092 files, 177M)
Built from source with: --without-multilib
and updated $PATHto include the path to the new gcc version
并更新$PATH为包含新 gcc 版本的路径
$ echo $PATH
/usr/local/Cellar/gcc/4.9.2_1:usr/local/bin:/opt/local/bin:/opt/local/sbin:/usr/bin:/bin:/usr/sbin:/sbin
however, gcc -vand which gccstill point to the old version, and building GraphChi still doesn't work due to the missing omp.h file
然而，gcc -v并which gcc仍然指向旧版本，并建立GraphChi仍然无法正常工作，由于缺少omp.h文件
Does anyone know what else I need to do?
有谁知道我还需要做什么？
Update
更新
locate omp.hreturned:
locate omp.h回来：
/usr/local/Cellar/apple-gcc42/4.2.1-5666.3/lib/gcc/i686-apple-darwin11/4.2.1/include/omp.h
/usr/local/Cellar/gcc/4.9.2_1/lib/gcc/4.9/gcc/x86_64-apple-darwin14.1.0/4.9.2/include/omp.h
/usr/local/Cellar/gfortran/4.8.2/gfortran/lib/gcc/x86_64-apple-darwin13.0.0/4.8.2/include/omp.h
my ~/.profile:
我的~/.profile：
export PATH=/usr/local/Cellar/gcc/4.9.2_1/lib/gcc/4.9/gcc/x86_64-apple-darwin14.1.0/4.9.2/include:/usr/local/Cellar/gcc/4.9.2_1/bin:usr/local/bin:/opt/local/bin:/opt/local/sbin:$PATH
回答by shrx
I solved this with installing gccwith homebrew:
我gcc用自制软件安装解决了这个问题：
brew install gcc --without-multilib
and then building the source code with
然后构建源代码
CC=gcc-5 CXX=g++-5 cmake ..
CC=gcc-5 CXX=g++-5 make -j7
回答by user2548418
Once you have installed gcc-4.9 with homebrew, it will automatically be in your path. To use OpenMP, you just need to make sure you are using the newly installed gcc-4.9, and it will be able to find omp.h.
使用自制软件安装 gcc-4.9 后，它将自动在您的路径中。要使用 OpenMP，您只需要确保您使用的是新安装的 gcc-4.9，它就能找到 omp.h。
In the case of GraphChi, you will have to go change line 3 of the Makefile to be gcc-4.9. From there, running make should just work. They describe this in their README, but at least the version they describe is out of date https://github.com/GraphChi/graphchi-cpp#problems-compiling-on-mac.
对于 GraphChi，您必须将 Makefile 的第 3 行更改为 gcc-4.9。从那里，运行 make 应该可以正常工作。他们在自述文件中对此进行了描述，但至少他们描述的版本已过时https://github.com/GraphChi/graphchi-cpp#problems-compiling-on-mac。
回答by tmlen
clangdoes not support OpenMP yet. Also gccby default links to Apple's LLVM clang compiler (not the GCC installed from brew).
Instead gcc-4.9would link to GCC. I think if -fopenmpis specified omp.his included automatically.
clang尚不支持 OpenMP。另外gcc在默认情况下链接到苹果的LLVM编译器铿锵（从酿造安装不GCC）。而是gcc-4.9会链接到 GCC。我认为 if-fopenmp是omp.h自动包含的。
It is possible to manually build a version of clang with OpenMP support, see http://clang-omp.github.io
可以手动构建具有 OpenMP 支持的 clang 版本，请参阅http://clang-omp.github.io
回答by tmlen
You shouldn't add the include path to PATH; instead, specify it as CFLAGS, including the -Ioption. You can exportthe CFLAGSvariable, or set it on the fly.
您不应将包含路径添加到PATH; 相反，将其指定为CFLAGS，包括-I选项。您可以export设置CFLAGS变量，或即时设置它。
Depending on how you compile things, you could do
根据你编译的方式，你可以做
CFLAGS=-I/usr/local/Cellar/gcc/4.9.2_1/lib/gcc/4.9/gcc/x86_64-apple-darwin14.1.0/4.9.2/include/omp.h gcc <whatever>
Of course, in this case you can specify it directly on the gcccommand (as -I/usr/local/....), but the CFLAGSvariable also works with configure(as configure often won't have an option to specify where it should look for specific include files); probably with make, or even for those installing a Python package: CFLAGS=-I... pip install <some-package>.
当然，在这种情况下，您可以直接在gcc命令上指定它(as -I/usr/local/....)，但该CFLAGS变量也可以使用configure（因为 configure 通常没有选项来指定它应该在哪里查找特定的包含文件）；可能带有make，甚至对于那些安装 Python 包的人来说：CFLAGS=-I... pip install <some-package>.
Other flags to consider are
其他要考虑的标志是
CXXFLAGS: C++ specific pre-processor flagsLDFLAGS: linker specific flags (e.g.LDFLAGS=-L/some/path/...for linking with dynamic libraries).CC: specify the C compiler to use. This is an easy way to avoid the built-ingccalias forclangon OS X. Just useCC=/usr/local/bin/gcc-4 makeor similar.CXX: specify the C++ compiler to use.
CXXFLAGS: C++ 特定的预处理器标志LDFLAGS: 链接器特定标志（例如LDFLAGS=-L/some/path/...用于链接动态库）。CC: 指定要使用的 C 编译器。这是避免OS X 上的内置gcc别名的简单方法clang。只需使用CC=/usr/local/bin/gcc-4 make或类似。CXX: 指定要使用的 C++ 编译器。
