Python 2/3 compatible C/C++ extension

This is a template to build from for C/C++ extensions that need to be compatible with both Python 2 and 3.

Build

python3 setup.py build

Output: build/lib.*-3.5/hello.cpython-35m-*.so

python2 setup.py build

Output: build/lib.*-2.7/hello.cpython-27m-*.so

Then try mv hello.cpp hello.c and modifying setup.py to reflect sources=['hello.c'], then repeating the above steps.

Run

Python3:

$ cd build/lib.*-3.5
$ python3
>>> import hello
>>> hello.hello('world3')
Hello, world3!
>>> hello.raise_error()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
hello.Error: something bad happened

Python2:

$ cd build/lib.*-2.7
$ python2
>>> import hello
>>> hello.hello('world2')
Hello, world2!
>>> hello.raise_error()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
hello.Error: something bad happened

Versions

• Windows 10 Linux Subsystem (4.4.0-43-Microsoft)
• Python 2.7.12 and 3.5.2
• x86_64-linux-gnu-gcc (Ubuntu 5.4.0-6ubuntu1~16.04.9) 5.4.0 20160609

References

• https://gist.github.com/physacco/2e1b52415f3a964ad2a542a99bebed8f/8ba2be17becb65015f505b87ed166f3163c14520
• https://docs.python.org/3/howto/cporting.html#module-initialization-and-state
• https://docs.python.org/2/extending/extending.html#intermezzo-errors-and-exceptions