focal (3) Condition.3o.gz

NAME

       Condition - Condition variables to synchronize between threads.

Module

       Module   Condition

Documentation

       Module Condition
        : sig end

       Condition variables to synchronize between threads.

       Condition  variables  are  used  when  one  thread  wants to wait until another thread has finished doing
       something: the former thread 'waits' on the condition variable, the latter thread 'signals' the condition
       when  it is done. Condition variables should always be protected by a mutex.  The typical use is (if D is
       a shared data structure, m its mutex, and c is  a  condition  variable):  Mutex.lock  m;  while  (*  some
       predicate  P  over D is not satisfied *) do Condition.wait c m done; (* Modify D *) if (* the predicate P
       over D is now satisfied *) then Condition.signal c; Mutex.unlock m

       type t

       The type of condition variables.

       val create : unit -> t

       Return a new condition variable.

       val wait : t -> Mutex.t -> unit

       wait c m atomically unlocks the mutex m and suspends the calling process on the condition  variable  c  .
       The  process will restart after the condition variable c has been signalled.  The mutex m is locked again
       before wait returns.

       val signal : t -> unit

       signal c restarts one of the processes waiting on the condition variable c .

       val broadcast : t -> unit

       broadcast c restarts all processes waiting on the condition variable c .