python setup.py build ctypes.CDLL: cannot open shared object file: No such file or directory

Question

I have implemented a ctypes wrapper called api.c, and I have the structure:

lib/api.c
foo.py
setup.py

Compiling api.c manually and calling ctypes.CDLL(path+'lib/api.so') inside foo.py works, where path is the absolute pathname.

Now, I want distribute it with setup.py:

setup(name='foo',
      ext_modules=[Extension('lib.api', ['lib/api.c'])]
     )

Installing with python setup.py develop -u --user works, too, because api.so appears in lib/.

With python setup.py install --user the code is compiled, too, but api.so appears in some build/bdist.linux-x86_64/egg/lib folder. Therefore importing the module results in OSError: /.../lib/api.so: cannot open shared object file: No such file or directory

So how can I distribute it with install and what should be the value of path?

related issues: How to include a shared C library in a Python package

Answer 1

I found that when adding the argument py_modules=['foo'] to setup, python setup.py install installed it properly in the site-packages directory. Thus

setup(name='foo',
      py_modules=['foo'],
      ext_modules=[Extension('lib.api', ['lib/api.c'])]
     )