Programming

in its man-page pthread_mutex_timedlock documents that the absolute timeout parameter should be based on the CLOCK_REALTIME clock or in the system clock. All this depending on whether the 'Timers option' is supported or not.

What do they mean by 'Timers option'? How could I tell for sure what time getter API should I use in my specific platform?

thanks,
Rodrigo

See man clock_gettime.

but that does not help me understand the statement in the pthread_mutex_timedlock man-page. All the examples I have seen around they use clock_gettime with option CLOCK_REALTIME before calling pthread_mutex_timedlock. But this did not work on my platform and what did work was to get the time by means of gettimeofday, convert to timespec and then call pthread_mutex_timedlock.

okay, I did not want to go into the details of my test, because I'm sure this will drive the discussion away from my basic question. How can I tell that in my platform the 'Timers option' (as in pthread_mutex_timedlock's man-page) is available or not?

In what manner did it 'not work' on your platform? runtime error? link error? compiler error? If it's just a runtime error, the obvious way would be to try it and see if it's available.

run time misbehavior. it did timeout much before the absolute time passed as parameter.

ps: something strange here. in my browser I read that your first reply says 'clock_gettime', but in the notification I got via email it says 'clock_getres'.

Ah, so it's not unavailable as much as just not working correctly. To see what's going on I'd need to see the code. A mistake on my part. I frequently edit my posts.

The term "Timers option" comes from the IEEE Std 1003.1-2004 (The Open Group Base Specifications, Issue 6) standard which was superceeded by IEEE Std 1003.1-2008 (The Open Group Base Specifications Issue 7).

See IEEE Std 1003.1-2004 XBD (Base Definitions) section 1.51 Codes for exact details. Essentially the "Time Options" consisted of optional POSIX.1b (Realtime extension) functionality denoted by the margin notation "[TMR]".

In this particular specification, clock_getres(), clock_gettime(), clock_settime() and more were denoted by [TMR] - hence the appropriate verbiage in the pthread_mutex_timedlock() man page.