Linux 2.6 - man page for sem_getvalue (linux section 3)
|Linux & Unix Commands - Search Man Pages
SEM_GETVALUE(3) Linux Programmer's Manual SEM_GETVALUE(3)
sem_getvalue - get the value of a semaphore
int sem_getvalue(sem_t *sem, int *sval);
Link with -pthread.
sem_getvalue() places the current value of the semaphore pointed to sem into the integer
pointed to by sval.
If one or more processes or threads are blocked waiting to lock the semaphore with
sem_wait(3), POSIX.1-2001 permits two possibilities for the value returned in sval: either
0 is returned; or a negative number whose absolute value is the count of the number of
processes and threads currently blocked in sem_wait(3). Linux adopts the former behavior.
sem_getvalue() returns 0 on success; on error, -1 is returned and errno is set to indicate
EINVAL sem is not a valid semaphore.
The value of the semaphore may already have changed by the time sem_getvalue() returns.
sem_post(3), sem_wait(3), sem_overview(7)
This page is part of release 3.55 of the Linux man-pages project. A description of the
project, and information about reporting bugs, can be found at
Linux 2012-05-13 SEM_GETVALUE(3)
All times are GMT -4. The time now is 07:49 AM.