Re: [PATCH] Make ENOSPC not fatal in semaphore creation

Thomas Munro <thomas.munro@gmail.com> writes:
> This has been fixed.  So now there are working basic futexes on Linux,
> macOS, {Free,Open,Net,Dragonfly}BSD (though capabilities beyond basic
> wait/wake vary, as do APIs).  So the question is whether it would be
> worth trying to do our own futex-based semaphores, as sketched above,
> just for the benefit of the OSes where the available built-in
> semaphores are of the awkward SysV kind, namely macOS, NetBSD and
> OpenBSD.  Perhaps we shouldn't waste our time with that, and should
> instead plan to use futexes for a more ambitious lwlock rewrite.

I kind of like the latter idea, but I wonder how we make it coexist
with (admittedly legacy) code for OSes that don't have usable futexes.

            regards, tom lane