m3core/src/unix/freebsd-3/Umsg.m3

 Copyright (C) 1990, Digital Equipment Corporation.         
 All rights reserved.                                       
 See the file COPYRIGHT for a full description.             
                                                            
      modified on Sat Apr 16 by rrw1000@hermes.cam.ac.uk    
      modified on Mon Mar 09 19:04:05 PST 1992 by muller    


UNSAFE MODULE Umsg;

PROCEDURE MSG_LOCK (<*UNUSED*> x: UNTRACED REF struct_msqid_ds) =
  BEGIN


    WITH mode = x.msg_perm.mode DO
      WHILE Word.And (mode, MSG_LCK) # 0 DO
        mode := Word.Or (mode, MSG_WANT);
        Unix.sleep (x.msg_first, PMSG); END;
      mode := Word.Or (mode, MSG_LCK); END;

  END MSG_LOCK;

PROCEDURE MSG_UNLOCK (<*UNUSED*> x: UNTRACED REF struct_msqid_ds) =
  BEGIN


    WITH mode = x.msg_perm.mode DO
      IF Word.And (mode, MSG_LCK) = 0 THEN
        Unix.panic (M3toC.TtoS (MSG_UNLOCK)); END;
      IF Word.And (mode, MSG_WANT) # 0 THEN
        Ultrix.wakeup (x.msg_first); END;
      mode := Word.And (mode, Word.Not (Word.Or (MSG_WANT, MSG_LCK))); END;

  END MSG_UNLOCK;

BEGIN
END Umsg.