Issue
I am trying to port a project (from linux) that uses Semaphores to Mac OS X however some of the posix semaphores are not implemented on Mac OS X
The one that I hit in this port is sem_timedwait()
I don't know much about semaphores but from the man pages sem_wait()
seems to be close to sem_timedwait
and it is implemented
From the man pages
sem_timedwait()
function shall lock the semaphore referenced by
sem
as in thesem_wait()
function. However, if the semaphore cannot be
locked without waiting for another process or thread to unlock the
semaphore by performing asem_post()
function, this wait shall be ter-
minated when the specified timeout expires
From my limited understanding of how semphores work I can see that sem_timedwait()
is safer, but I still should be able to use sem_wait()
Is this correct? If not what other alternatives do I have...
Thanks
Solution
It's likely that the timeout is important to the operation of the algorithm. Therefore just using sem_wait()
might not work.
You could use sem_trywait()
, which returns right away in all cases. You can then loop, and use a sleep interval that you choose, each time decrementing the total timeout until you either run out of timeout or the semaphore is acquired.
A much better solution is to rewrite the algorithm to use a condition variable, and then you can use pthread_cond_timedwait()
to get the appropriate timeout.
Answered By - Jared Oberhaus Answer Checked By - Mildred Charles (WPSolving Admin)