It must be invoked with either a logical keyword on the command line to specify the mode of operation, or using the PROMPT keyword. The modes available are:
CQUALITY IGNORE - Sets the temporary bad quality bit, (=CIGNORE)
leaving the rest unaltered.
CQUALITY RESTORE - Clears the temporary bad quality bit, (=CRESTORE)
restoring the original quality value.
CQUALITY SET - Sets quality to a specified value. (=CSETQUAL)
CQUALITY NOT - Complements existing quality values.
CQUALITY AND - ANDs existing quality with specified
value.
CQUALITY OR - ORs existing quality with specified
value.
CQUALITY EOR - EORs existing quality with specified
value.