Re: darwin pgsql patches

Ian Lance Taylor <ian(at)airs(dot)com> writes:
> The POSIX semaphore interface comes from the pthreads work. In my
> opinion, the System V IPC calls are badly designed.

Badly implemented, I'll grant you --- the resource limits in a typical
configuration are ridiculously low. I'm not sure the API as such is
particularly good or bad.

> However, on systems which do fully implement POSIX semaphores, it
> should be easy for Postgres to use them. They should be created in
> the shared memory segment.

Huh? Are POSIX semaphores objects in user memory space, instead of
in the kernel? I'm getting more and more confused. Where can I find
a description of the POSIX version of semaphores?

BTW, should I expect that POSIX also ignored the SysV IPC spec for
shared memory?

regards, tom lane