Condition Variables
The BSD portion of Mac OS X provides msleep, wakeup, and wakeup_one, which are equivalent to condition variables with the addition of an optional time-out. You can find these functions in sys/proc.h in the Kernel framework headers.
msleep(void *channel, lck_mtx_t *mtx, int priority, const char *wmesg, struct timespec *timeout); |
msleep0(vvoid *channel, lck_mtx_t *mtx, int priority, const char *wmesg, uint64_t deadline); |
wakeup(void *channel); |
wakeup_one(void *channel); |
Since msleep is more commonly used for waiting a predetermined period of time, the wakeup and wakeup_one calls are discussed along with msleep in more detail in the section “Using msleep” as part of the “Miscellaneous Kernel Services” chapter.
Outside the BSD portion of the kernel, condition variables may be implemented using semaphores.
