如何告诉distutils使用gcc？

Question

我想用Cython包装一个包含C和OpenMP代码的测试项目，并通过一个setup.py文件用distutils构建它。我的文件内容是这样的：

from distutils.core import setup
from distutils.extension import Extension
from Cython.Build import cythonize
from Cython.Distutils import build_ext


modules = [Extension("Interface",
                     ["Interface.pyx", "Parallel.cpp"],
                     language = "c++",
                     extra_compile_args=["-fopenmp"],
                     extra_link_args=["-fopenmp"])]

for e in modules:
    e.cython_directives = {"embedsignature" : True}

setup(name="Interface",
     cmdclass={"build_ext": build_ext},
     ext_modules=modules)

-fopenmp标志与gcc一起用于编译和链接OpenMP。然而，如果我只是调用

cls ~/workspace/CythonOpenMP/src $ python3 setup.py build

无法识别此标志，因为编译器为clang:

running build
running build_ext
skipping 'Interface.cpp' Cython extension (up-to-date)
building 'Interface' extension
cc -Wno-unused-result -fno-common -dynamic -DNDEBUG -g -O3 -Wall -Wstrict-prototypes -I/usr/local/include -I/usr/local/opt/sqlite/include -I/usr/local/Cellar/python3/3.3.0/Frameworks/Python.framework/Versions/3.3/include/python3.3m -c Interface.cpp -o build/temp.macosx-10.8-x86_64-3.3/Interface.o -fopenmp
clang: warning: argument unused during compilation: '-fopenmp'
cc -Wno-unused-result -fno-common -dynamic -DNDEBUG -g -O3 -Wall -Wstrict-prototypes -I/usr/local/include -I/usr/local/opt/sqlite/include -I/usr/local/Cellar/python3/3.3.0/Frameworks/Python.framework/Versions/3.3/include/python3.3m -c Parallel.cpp -o build/temp.macosx-10.8-x86_64-3.3/Parallel.o -fopenmp
clang: warning: argument unused during compilation: '-fopenmp'
Parallel.cpp:24:10: warning: unknown pragma ignored [-Wunknown-pragmas]
        #pragma omp parallel for
                ^
1 warning generated.
c++ -bundle -undefined dynamic_lookup -L/usr/local/lib -L/usr/local/opt/sqlite/lib build/temp.macosx-10.8-x86_64-3.3/Interface.o build/temp.macosx-10.8-x86_64-3.3/Parallel.o -o build/lib.macosx-10.8-x86_64-3.3/Interface.so -fopenmp
ld: library not found for -lgomp
clang: error: linker command failed with exit code 1 (use -v to see invocation)
error: command 'c++' failed with exit status 1

我尝试指定gcc失败：

cls ~/workspace/CythonOpenMP/src $ python3 setup.py build --compiler=g++-4.7
running build
running build_ext
error: don't know how to compile C/C++ code on platform 'posix' with 'g++-4.7' compiler

如何告诉distutils使用gcc？

Answer 1

我只是看了一下distutils源代码，并且--compiler选项需要unix、msvc、cygwin、mingw32、bcpp或emx。它通过检查CC环境变量来检查所需的编译器名称。尝试这样调用构建：

CC=gcc python setup.py build

您不需要设置CXX，它不会检查这一点。

Answer 2

以防其他人在Windows下面临同样的问题（CC环境变量不会产生任何影响）：

• 创建文件"C：\Python27\Lib\distutils\distutils.cfg"并将其写入：

代码：

[build]
compiler = mingw32

• 从文件"C：\Python27\Lib\distutils\cygwinccompiler.py"中删除"-mno-cygwin"gcc选项的所有实例：

这个：

    self.set_executables(compiler='gcc -mno-cygwin -O -Wall',
                         compiler_so='gcc -mno-cygwin -mdll -O -Wall',
                         compiler_cxx='g++ -mno-cygwin -O -Wall',
                         linker_exe='gcc -mno-cygwin',
                         linker_so='%s -mno-cygwin %s %s'
                                    % (self.linker_dll, shared_option,
                                       entry_point))

变成这样：

self.set_executables(compiler='gcc -O -Wall',
                     compiler_so='gcc -mdll -O -Wall',
                     compiler_cxx='g++ -O -Wall',
                     linker_exe='gcc',
                     linker_so='%s %s %s'
                                % (self.linker_dll, shared_option,
                                   entry_point))

希望这会有所帮助，即使它与OP的实际需求没有直接关系（但仍然与问题的标题相关…）

Answer 3

尝试使用os.environ.从setup.py内部设置"CC"环境变量