Re: warnings for invalid function casts

Peter Eisentraut <peter(dot)eisentraut(at)2ndquadrant(dot)com> writes:
> On 2020-06-30 21:38, Tom Lane wrote:
>> In any case, I think the issue here is what is the escape hatch for saying
>> that "I know this cast is okay, don't warn about it, thanks". Treating
>> "void (*) (void)" as special for that purpose is nothing more nor less
>> than a kluge, so another compiler might do it differently. Given the
>> POSIX restriction, I think we could reasonably use "void *" instead.

> I think gcc had to pick some escape hatch that is valid also outside of
> POSIX, so they just had to pick something. If we're disregarding
> support for these Harvard architecture type things, then we might as
> well use void * for easier notation.

As long as it's behind a typedef, the code will look the same in any
case ;-).

> Btw., one of the hunks in my patch was in PL/Python. I have found an
> equivalent change in the core Python code, which does make use of void
> (*) (void): https://github.com/python/cpython/commit/62be74290aca

Given that gcc explicitly documents "void (*) (void)" as being what
to use, they're going to have a hard time changing their minds about
that ... and gcc is dominant enough in this space that I suppose
other compilers would have to be compatible with it. So even though
it's theoretically bogus, I suppose we might as well go along with
it. The typedef will allow a centralized fix if we ever find a
better answer.

regards, tom lane