[PATCH v3 2/6] nptl: Add POSIX-proposed sem_clockwait

[Florian Weimer]

* Mike Crowe:

> On Wednesday 05 June 2019 at 18:07:18 -0300, Adhemerval Zanella wrote:
>> On 27/05/2019 17:03, Mike Crowe wrote:
>> > Add:
>> > 
>> >  int sem_clockwait (sem_t *sem, clockid_t clock, const struct timespec *abstime)
>> > 
>> > which behaves just like sem_timedwait, but measures abstime against the
>> > specified clock. Currently supports CLOCK_REALTIME and CLOCK_MONOTONIC and
>> > sets errno == EINVAL if any other clock is specified.
>> 
>> For non-POSIX definition we will need to first export it as a GNU extension
>> with a possible non-reserved name and later, when it is included on the 
>> standard, to add an alias to the expected name.  
>> 
>> The usual naming scheme is to append the _np suffix (non-portable) on 
>> implementation, similar to recent posix_spawn file action extensions.
>> In this case it would be sem_clockwait_np.

> I thought we went through this before[1] and agreed that the _np suffix wasn't
> necessary in this case. However, I couldn't find a reply to Florian
> agreeing to that.

Upon second thought, I agree with Adhemerval here.  We should use a
function with the _np suffix, otherwise we'll be in a world of pain if
something else is standardized.

Thanks,
Florian