Locks for mutual exclusion.
Mutexes (mutual-exclusion locks) are used to implement critical sections
and protect shared mutable data structures against concurrent accesses.
The typical use is (if
m is the mutex associated with the data structure
Mutex.lock m; (* Critical section that operates over D *); Mutex.unlock m
The type of mutexes.
val create :
unit -> t
Return a new mutex.
val lock :
t -> unit
Lock the given mutex. Only one thread can have the mutex locked at any time. A thread that attempts to lock a mutex already locked by another thread will suspend until the other thread unlocks the mutex.
Sys_errorwas not raised for recursive locking (platform-dependent behaviour)
Sys_errorif the mutex is already locked by the thread calling
val try_lock :
t -> bool
Mutex.lock, but does not suspend the calling thread if
the mutex is already locked: just return
in that case. If the mutex is unlocked, lock it and
val unlock :
t -> unit
Unlock the given mutex. Other threads suspended trying to lock
the mutex will restart. The mutex must have been previously locked
by the thread that calls
Sys_errorwas not raised when unlocking an unlocked mutex or when unlocking a mutex from a different thread.
Sys_errorif the mutex is unlocked or was locked by another thread.