49 lines
2.2 KiB
OCaml
49 lines
2.2 KiB
OCaml
(***********************************************************************)
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(* *)
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(* Objective Caml *)
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(* *)
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(* Xavier Leroy and Damien Doligez, INRIA Rocquencourt *)
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(* *)
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(* Copyright 1996 Institut National de Recherche en Informatique et *)
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(* en Automatique. All rights reserved. This file is distributed *)
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(* under the terms of the GNU Library General Public License. *)
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(* *)
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(***********************************************************************)
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(* $Id$ *)
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(* Module [Condition]: condition variables to synchronize between threads *)
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(* Condition variables are used when one thread wants to wait until another
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thread has finished doing something: the former thread ``waits'' on the
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condition variable, the latter thread ``signals'' the condition when it
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is done. Condition variables should always be protected by a mutex.
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The typical use is (if [D] is a shared data structure, [m] its mutex,
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and [c] is a condition variable):
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[
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Mutex.lock m;
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while (* some predicate P over D is not satisfied *) do
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Condition.wait c m
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done;
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(* Modify D *)
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if (* the predicate P over D is now satified *) then Condition.signal c;
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Mutex.unlock m
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]
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*)
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type t
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(* The type of condition variables. *)
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val create: unit -> t
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(* Return a new condition variable. *)
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val wait: t -> locking:Mutex.t -> unit
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(* [wait c m] atomically unlocks the mutex [m] and suspends the
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calling process on the condition variable [c]. The process will
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restart after the condition variable [c] has been signalled.
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The mutex [m] is locked again before [wait] returns. *)
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val signal: t -> unit
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(* [signal c] restarts one of the processes waiting on the
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condition variable [c]. *)
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val broadcast: t -> unit
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(* [broadcast c] restarts all processes waiting on the
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condition variable [c]. *)
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