acquire-timeout ( semaphore timeout -- )
Counting semaphores

Prev:	acquire ( semaphore -- )
Next:	release ( semaphore -- )

Vocabulary
concurrency.semaphores

Inputs

semaphore	a semaphore
timeout	a duration or f

Outputs
None

Word description
If the semaphore has a non-zero count, decrements it and returns immediately. Otherwise, if the timeout is f, waits indefinitely for the semaphore to be released. If the timeout is not f, waits a certain period of time, and if the semaphore still has not been released, throws an error.

Errors
Throws an error if the timeout expires before the semaphore is released.

Definition

USING: accessors kernel math ;

IN: concurrency.semaphores

: acquire-timeout ( semaphore timeout -- )
    over count>> zero? [ dupd wait-to-acquire ] [ drop ] if
    [ 1 - ] change-count drop ;