PATHMac OS 8 Developer Documentation > Operating System Services > Multiprocessing Services >

Adding Multitasking Capability to Applications Using Multiprocessing Services

   

MPWaitOnSemaphore

Waits on a semaphore

OSStatus MPWaitOnSemaphore (
                     MPSemaphoreID semaphore,
                     Duration timeout);
semaphore
A value of type MPSemaphoreID that specifies the ID of the semaphore you want to wait on.
timeout
A value of type Duration that specifies the maximum time the function should wait before timing out. See Timer Duration Constants for a list of constants you can use to specify the wait interval.
function result
A result code. See Result Codes for a list of possible values.
DISCUSSION

If the value of the semaphore is greater than zero, the value is decremented and the function returns with noErr . Otherwise, the task is blocked awaiting a signal until the specified timeout is exceeded.

If you call this function from a cooperative task, you should specify only kDurationImmediate for the timeout length; other waits will cause the task to block.

VERSION NOTES

Introduced with Multiprocessing Services 1.0.

SEE ALSO

The function MPSignalSemaphore .

© 1999 Apple Computer, Inc. – (Last Updated 07 May 99)