Solved: [TS3.10] Multithreading problem

On Wed, 27 Sep 2006 19:28:45 +0200 (MSZ), Peter Engels wrote:

>This works very well, if only one process is waiting for input, but it
>will obviously not work, with two or more processes, because it is not
>clear, whether the event belongs to the calling process or not. Any
>ideas to solve this problem in an easy way?
>
The problem is solved so far, perhaps someone else is interested, so
here is a possible solution, that works fine for me:

The module SYSTEM contains an undo***ented procedure

PROCEDURE CurrentProcess() : ADDRESS;

which can be used to solve the problem. I have changed the procedure
GetEvent to use the procedure CurrentProcess:

PROCEDURE GetEvent (VAR Event : EVENT);
VAR OldProc : ADDRESS;
BEGIN
  Lock;
  OldProc := ProcAdr;
  ProcAdr := CurrentProcess();
  Unlock;
  LOOP
    WAIT (sEventAvailable);
    Lock;
    IF ProcAdr = CurrentProcess () THEN
      Event := PopEvent ();
      ProcAdr := OldProc;
      Unlock;
      RETURN
    END;
    Unlock;
    Delay (0);
  END
END GetEvent;

where ProcAdr is a global variable in the module containing GetEvent
and is initialized to NIL.

MfG / Regards

	Peter Engels

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