PyPy cffi builtin version

[EarthenGarland]

Here it says the following:

cffi/setup.py

Lines 180 to 182 in 7020b2d

	# On PyPy, cffi is preinstalled and it is not possible, at least for now,
	# to install a different version. We work around it by making the setup()
	# arguments mostly empty in this case.

This comment was last edited 10 years ago, or at least that's what git blame says. Does it still hold true, or can a built from source cffi be used instead of the PyPy builtin?

[arigo]

Hi Earthen,

On Wed, 1 Oct 2025 at 09:10, EarthenGarland ***@***.***> wrote: can a built from source cffi be used instead of the PyPy builtin?

For all practial purposes, no, the comment is still correct. Maybe it would *work* nowadays, though I didn't try---and nobody should: it would be 2 or 3 orders of magnitude slower. PyPy's cffi is integrated with his JIT compiler and generates efficient assembly code. If you tried to compile and use the CPython cffi instead, what becomes a simple assembly CALL instruction would go through multiple levels of slow abstraction (starting with but not limited to the relatively high overhead of emulating the CPython C API). If you're worried about cffi becoming version 2.0, just note that the cffi API is still 99.9% unchanged. The version number 2.0 is useful to show that there was a major internal upgrade of the implementation for CPython. For PyPy, it doesn't change anything. Armin Rigo