Re: BUG #16920: Can't compile PostGIS with MingW64 against PostgreSQL 14 head

Hi,

On 2021-03-19 20:37:17 -0400, Tom Lane wrote:
> Andres Freund <andres(at)anarazel(dot)de> writes:
> > On 2021-03-15 12:12:59 -0400, Tom Lane wrote:
> >> Although I remain worried about this being an ABI break, I don't think
> >> we are locked into it until we get to beta, or maybe even RC stage.
>
> > Could it make sense to define sigjmp_buf as a union over the potentially
> > needed implementations? That'd allow us to switch back without an ABI
> > break if we discover a problem with the gcc approach.
>
> No, it'd still be an ABI break, because the setjmp and the longjmp calls
> have to use the same implementation. Ain't gonna work if elog.c tries
> to throw via mingw's longjmp() while some extension contains a PG_TRY
> that uses __builtin_setjmp(). Nor vice versa.

Yea, I momentarily forgot that we can't easily wrap setjmp in a
function... I guess we could just make sigsetjmp set a flag that
indicates which longjmp to use, but that's probably more complication
than the issue / mingw warrants.

- Andres