S
PL_
PL_
PL_READVU{%}FROM{%},{%},{%}{WTHEN\ELSE}
*
      LOOP
         READVU {%1} FROM {%2} , {%3} , {%4} LOCKED
            L$$$ = YES
         END THEN
            L$$$ = NO
            T$$$ = YES
         END ELSE
            L$$$ = NO
            T$$$ = NO
         END
      WHILE L$$$ DO
         SLEEP .1
      REPEAT
      IF T$$$ {%5}
