When pid = 0, the scheduling policy is returned for the calling process If pid is negative, the behavior is unspecified The values that can be returned by sched_getscheduler() are defined in the sched.h header sched_getscheduler() returns the scheduling policy of the specified process on success sched_getscheduler() returns -1 on failure sched_getscheduler() sets errno == ESRCH if the pid cannot be found sched_getscheduler() sets errno == EPERM if the requesting process does not have permission