On 04/07/2018 05:59, dieter wrote:
..........
"libffi" contains the so called "foreign function interface"
(an interface that allows code written in one language to call
code written in another language). Likely, "ctypes" depends
on it.
Since some time, "ctypes" is part of Python's standard library.
It is likely, that the Python test suite contains tests verifying
that it could be build successfully.
Your observations seem to indicate that "ctypes" contains its
own "foreign function interface" specification and that this
specification does not fit to the libraries available on your
system. The "with-system-ffi" likely tells the Python generation
process to use the system "foreign function interface" rather
than its own.
I don't disagree with the above. I think the issue is that the configure process did not say anything about this. If ctypes is
required and cannot be built then ./configure ...... should probably tell me; if that's not possible then the make step should do
so and fail to complete. Failing at make install seems a bit late.
I have to admit that I no longer understand how python builds its extensions; there used to be a step where you configured
Modules/Setup*, but that seems no longer required.
Any how as an experiment it seems that if I do have the libffi-dev package installed then the with-system-ffi flag is not required
and the make install does work. It might be that make silently allows extension builds to fail even if they are 'required' and
that later causes an error in the install phase.
--
Robin Becker
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