How to tell distutils to use gcc?

问题

I want to wrap a test project containing C++ and OpenMP code with Cython, and build it with distutils via a setup.py file. The content of my file looks like this:

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)

The -fopenmp flag is used with gcc to compile and link against OpenMP. However, if I just invoke

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

this flag is not recognized, because the compiler is 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

I\'ve unsucessfully tried to specify gcc:

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

How can I tell distutils to use gcc?

回答1:

Try setting the "CC" environment variable from inside the setup.py with os.environ.

回答2:

Just in case some others are facing the same problem under Windows (where CC environment variable wouldn't have any effect) :

Create file "C:\Python27\Lib\distutils\distutils.cfg" and write this inside :

Code :

[build]
compiler = mingw32

Remove all instances of "-mno-cygwin" gcc option from file "C:\Python27\Lib\distutils\cygwinccompiler.py" :

This :

    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))

Becomes this :

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))

The second point can be necessary in case you are using a recent version of gcc, where the deprecated option -mno-cygwin has been removed.

Hope this will help even if it is not directly related to the OP real needs (but still related to the question's title...)

回答3:

I just took a look at the distutils source, and the --compiler option expects "unix", "msvc", "cygwin", "mingw32", "bcpp", or "emx". It checks the compiler name you want by checking the CC environment variable. Try calling build like this:

CC=gcc python setup.py build

You don't need to set CXX, it doesn't check for that.

回答4:

According to this wiki, Python versions after 3.4 do not support MinGW anymore. CPython 3.7 for Windows is compiled with MSC v.1916. When I try to use above-mentioned method with distutils.cfg, I then get an error from distutils: Unknown MS Compiler Version 1916. Looks like it has a hardcoded table of msvcr libraries in its cygwincompiler.py file (which is also responsible for MinGW), and last version known to that file is 1600 from VS2010 / MSVC 10.0.

回答5:

Try this: http://mail.python.org/pipermail/distutils-sig/2002-August/002944.html

In short, it appears that you should try: python setup.py build --compiler=g++ first.

来源：https://stackoverflow.com/questions/16737260/how-to-tell-distutils-to-use-gcc

标签

python

compiler-errors

cython

distutils