module Counting: sig .. endtype t
The type of counting semaphores.
val make : int -> t
make n returns a new counting semaphore, with initial value n.
The initial value n must be nonnegative.
Invalid_argument if n < 0val release : t -> unit
release s increments the value of semaphore s.
If other threads are waiting on s, one of them is restarted.
If the current value of s is equal to max_int, the value of
the semaphore is unchanged and a Sys_error exception is raised
to signal overflow.
Sys_error if the value of the semaphore would overflow max_intval acquire : t -> unit
acquire s blocks the calling thread until the value of semaphore s
is not zero, then atomically decrements the value of s and returns.
val try_acquire : t -> bool
try_acquire s immediately returns false if the value of semaphore s
is zero. Otherwise, the value of s is atomically decremented
and try_acquire s returns true.
val get_value : t -> int
get_value s returns the current value of semaphore s.
The current value can be modified at any time by concurrent
Semaphore.Counting.release and Semaphore.Counting.acquire operations. Hence, the get_value
operation is racy, and its result should only be used for debugging
or informational messages.