8.3 Single extension module

Extension modules are specified using the ext_modules option. package_dir has no effect on where extension source files are found; it only affects the source for pure Python modules. The simplest case, a single extension module in a single C source file, is:

<root>/
        setup.py
        foo.c

If the foo extension belongs in the root package, the setup script for this could be

from distutils.core import setup
from distutils.extension import Extension
setup(name='foobar',
      version='1.0',
      ext_modules=[Extension('foo', ['foo.c'])],
      )

If the extension actually belongs in a package, say foopkg, then

With exactly the same source tree layout, this extension can be put in the foopkg package simply by changing the name of the extension:

from distutils.core import setup
from distutils.extension import Extension
setup(name='foobar',
      version='1.0',
      ext_modules=[Extension('foopkg.foo', ['foo.c'])],
      )

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