> We've had this discussion before, you know, 2006.
> MS is asserting on preconditions that are undefined by the standard.
> As such, they are not in violation.

I remember, and you were already wrong back then :-)

MS asserts (in winsig.c) that the signal number in signal() is one
of the explicit list of supported or ignored signals; if it isn't,
it aborts. This is in violation to ISO C, 7.14.1.1p8, which specifies
that SIG_ERR must be returned and errno set.

It is true that Python *also* invokes undefined behavior in certain
cases; contributions to eliminate these are welcome.