File: PlotMonitor.mesa, Copyright (C) 1985 by Xerox Corporation. All rights reserved.
Last Edited by:
Sweetsun Chen, July 22, 1985 6:24:32 pm PDT
DIRECTORY
PlotOps USING [Handle];
PlotMonitor:
CEDAR
MONITOR
EXPORTS PlotOps = {
Lock:
PUBLIC
ENTRY
PROC [handle: PlotOps.Handle] = {
ENABLE UNWIND => NULL;
IF handle = NIL THEN RETURN;
WHILE handle.locked DO WAIT handle.unlocked; ENDLOOP;
handle.locked ← TRUE;
}; -- Lock
Unlock:
PUBLIC
ENTRY
PROC [handle: PlotOps.Handle] = {
ENABLE UNWIND => NULL;
IF handle #
NIL
THEN {
handle.locked ← FALSE;
BROADCAST handle.unlocked;
};
}; -- Unlock
}.
CHANGE
LOG.
Created by: SChen in Cedar5.
SChen, July 22, 1985 6:22:31 pm PDT, => Cedar6.0.