(* Copyright (C) 1987 Jensen & Partners International *)
DEFINITION MODULE Process;

TYPE SIGNAL;


PROCEDURE StartScheduler;
(* start the time sliced scheduler *)

PROCEDURE StopScheduler;
(* stops the time sliced scheduler *)

PROCEDURE StartProcess(P: PROC; N: CARDINAL; Pr: CARDINAL);
(* Start a new process *)


PROCEDURE SEND(s: SIGNAL);
(* Send a signal *)

PROCEDURE WAIT(s: SIGNAL);
(* Wait for signal *)

PROCEDURE Notify(s: SIGNAL);
(*
   Causes a task waiting on signal s to be scheduled when possible,
   (e.g. at next time slice).
   If no-one is waiting on s then the call has NO effect.
   This call CANNOT cause reschedule, so may be used by an interrupt
   handler to safely notify another process of an events occurance.
*)

PROCEDURE Awaited(s: SIGNAL) : BOOLEAN;
(* Returns if any process are waiting on signal *)

PROCEDURE Init(VAR s: SIGNAL);
(* Initialize a signal *)


PROCEDURE Delay(T: CARDINAL);
(* delays for at least T timeslices *)

PROCEDURE Lock;
(*
   Critical region lock. Prevents the current process from
   being de-scheduled by timeslicing, until a call to Unlock.
   Calls to Lock may be nested.
*)

PROCEDURE Unlock;
(* Unlock procedure, always paired with a call to Lock. *)



END Process.