https://setuptools.pypa.io/en/latest/userguide/distribution.html#distributing-extensions-compiled-with-cython https://setuptools.pypa.io/en/latest/userguide/dis

https://setuptools.pypa.io/en/latest/userguide/distribution.html#distributing-extensions-compiled-with-cython https://setuptools.pypa.io/en/latest/userguide/distribution.... > setuptools will detect at build time whether Cython is installed or not. If Cython is not found setuptools will ignore pyx files. > To ensure Cython is available, include Cython in the build-requires section of your pyproject.toml: [build-system] requires=[..., "cython"] > Built with pip 10 or later, that declaration is sufficient to include Cython in the build. For broader compatibility, declare the dependency in your setup-requires of setup.cfg: