Making Cython work with Python 3.4 on Anacondas, W

Question

I have just installed Python 3.4 on my Windows 7 64-bit machine, using Anaconda/Condas.

When I run the "hello world" cython example I get this error:

[py34] C:\Users\Jon\Documents\GitHub\CythonFunctions\cython_funcs>python setup.py build_ext --inplace
running build_ext
building 'cython_funcs.hello' extension
C:\Anaconda\envs\py34\MinGW\bin\gcc.exe -mdll -O -Wall -IC:\Anaconda\envs\py34\include -IC:\Anaconda\envs\py34\include -c hello.c -o build\temp.win-amd64-3.4\Release\hello.o
writing build\temp.win-amd64-3.4\Release\hello.def
C:\Anaconda\envs\py34\MinGW\bin\gcc.exe -shared -s build\temp.win-amd64-3.4\Release\hello.o build\temp.win-amd64-3.4\Release\hello.def -LC:\Anaconda\envs\py34\libs -LC:\Anaconda\envs\py34\PCbuild\amd6
4 -lpython34 -lmsvcr100 -o C:\Users\Jon\Documents\GitHub\CythonFunctions\cython_funcs\cython_funcs\hello.pyd
build\temp.win-amd64-3.4\Release\hello.o:hello.c:(.text+0x314): undefined reference to `__imp__PyThreadState_Current'
build\temp.win-amd64-3.4\Release\hello.o:hello.c:(.text+0x493): undefined reference to `__imp__Py_NoneStruct'
build\temp.win-amd64-3.4\Release\hello.o:hello.c:(.text+0x97b): undefined reference to `__imp_PyExc_ImportError'
collect2.exe: error: ld returned 1 exit status
error: command 'C:\\Anaconda\\envs\\py34\\MinGW\\bin\\gcc.exe' failed with exit status 1

From searching stackoverflow and google, this error occurs when the gcc and python versions are not both either 32 bit or 64 bit.

I have checked that my Python is 64 bit. The MinGW that I have, as can be seen from the path below, was part of my Python installation. How can I check if it is 64 bit or not? Or could this error be due to something else?

Update:

Strangely, the Ipython cythonmagic command here works fine:

http://docs.cython.org/src/quickstart/build.html?highlight=cythonmagic

Answer 1

This might work for linking problems (to be done in a temporary directory; copy instead of cp if not in a msys2 environment)

gendef c:/Windows/System32/python34.dll
dlltool -U -d python34.def -l libpython34.dll.a
cp libpython34.dll.a c:/Python34/libs

If gendef is unable to access python34.dll, it can be copied using windows explorer before gendef command.

gendef is available at least with mingw-w64 packages.

Answer 2

I ran into a similar problem with Anaconda but it worked when I stopped trying to compile in the py34 directory. Instead put your helloworld.pyx file (make sure you change it to that extension .pyx as well) in the Anaconda3 folder along with the setup.py and when you compile make sure you are in the Anaconda3 folder as well so C:\Anaconda3 python setup.py build_ext --inplace. If memory serves this ran just fine.

Answer 3

Your gcc line is missing a define: -DMS_WIN64. Anaconda (I presume) have modified the file cygwinccompiler.py in Lib/distutils of 2.7 envs, but this modification is not present in the distutils of the 3.4 env. I was getting different errors to yours, but this change fixed my setup.

Answer 4

One way would be to conda remove libpython (this will cause distutils to not use mingw), and install Visual Studio 2010, and use that to compile.