POSIX Condition Variables Clock Attribute Support

[Joel Sherrill]

I am beginning to add support for the clock attribute to POSIX condition variables.

​http://pubs.opengroup.org/onlinepubs/9699919799/functions/pthread_condattr_getclock.html

Since the clock can't be a CPU time clock, that leaves CLOCK_MONOTONIC and CLOCK_REALTIME. The thread queue is based on CLOCK_MONOTONIC and does not have an option to use CLOCK_REALTIME. Threads and timers waiting on CLOCK_REALTIME should be impacted by time of day changes.

​https://docs.google.com/document/d/1GsGer0t84p-nUfZFim4Ty0LTDYNhgKBvlwip_gLQjTY/edit?usp=sharing is a Google doc with my notes so far in it on POSIX clocks. I will move it to the Wiki as it turns into something more concrete than notes and reflects plans/code.

So the first issue is how best to alter the thread queue to support using either clock source? And what does that do to the current ticks based API since you proposed different time representations for the ticks (relative/monotonic) and seconds (absolute/realtime) structures?

[Joel Sherrill <joel@…>]

In 6131b849081335e101f92b4a99e01572153d44f5/rtems:

Add pthread_condattr_getclock() and pthread_condattr_setclock()

updates #2608.

[Joel Sherrill]

Gedare.. I checked and think this is implemented and I thought you did the final part of the work. If you concur it is implemented, please close.

[Sebastian Huber]

See also #3182.

[Sebastian Huber]

Milestone renamed