Re: Switch to unnamed POSIX semaphores as our preferred sema code?

Thomas Munro <thomas(dot)munro(at)enterprisedb(dot)com> writes:
> On Tue, Oct 11, 2016 at 5:57 AM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> (I'm a little suspicious that older variants of FreeBSD might not
>> have working sem_init, like the other *BSD variants, necessitating
>> a run-time test there. But we'll cross that bridge when we come
>> to it.)

> The sem_init man page from FreeBSD 8.4[1] (EOL August 2015) and earlier said:
> This implementation does not support shared semaphores, and reports this
> fact by setting errno to EPERM.
> FreeBSD 9.0 (released January 2012) reimplemented semaphores and
> removed those words from that man page[2].

Yeah, in subsequent googling I found other mentions of this having been
added in FreeBSD 9.0. But that will be more than 5 years old by the
time PG 10 gets out.

> All current releases[3] support it, though I guess there may be 8.4
> machines out there a year and a bit after EOL.

We don't have anything older than 9.0 in the buildfarm, which I take
to indicate that nobody particularly cares about older versions anymore.
I would just as soon not add a run-time test in configure (it breaks
cross-compiles), so I'd rather wait and see if anyone complains.

regards, tom lane