relationship between C/C++ Extension and cython

[ardeal]

Hi,

Please check the following 2 pieces of code.
in the first code, we don't use cython, but in the second, we use cython.
my questions are:
what is the difference of the following code?
ext_modules=[] and ext_modules=cython() both works, does this mean that cython return a list which includes Extension?
is there any doc about the explanation of the upper question?

setup(
	name = 'hello'
    ext_modules=[
        Extension('foo',
                  glob(path.join(here, 'src', '*.c')),
                  libraries = [ 'rt' ],
                  include_dirs=[numpy.get_include()])
    ]
)

setup(
	name = 'hello'
    ext_modules=cython([
        Extension('foo',
                  glob(path.join(here, 'src', '*.c')),
                  libraries = [ 'rt' ],
                  include_dirs=[numpy.get_include()])
    ])
)

[abravalheri]

Hi @ardeal, as far as I am aware there is no cython function exposed by setuptools.
Also I don't understand why you are using a cython function with an extension written in C.

It is not clear for me how do those things play out... I would recommend having a look on the Cython docs: https://cython.readthedocs.io/en/latest/

[ardeal]

Hi @abravalheri ,

Sorry, I input wrong words in my post. in my post, cython should be cythonize.
I do see some code with cythonize which works.

my doubt is: For some code there is cythonize, but for some other code, there isn't cythonize.

[abravalheri]

Setuptools natively supports .c files in Extensions. That is a built-in capability.
You don't use cythonize with C extensions.

You just use cythonize when you have .pyx files¹, because it converts .pyx files into .c (have a look on the Cython docs for more details).

Footnotes

1. kind of... if you use the Extension class properly, you might not need to use cythonize at all because setuptools will try to call itself cythonize on the .pyx files. I recommend giving it a try and see if that works, if not you can revert to cythonize. ↩

[ardeal]

got it, thanks, @abravalheri
The comments in your link help:
you might not need to use cythonize at all because setuptools will try to call itself cythonize on the .pyx files