The PRTOV macro tests for channel 9 or 12 of the printer carriage control tape or the forms control buffer (FCB). An overflow condition causes either an automatic skip to channel 1 or, if specified, transfer of control to your routine for overflow processing. If you specify an overflow exit routine, set DCBIFLGS to X'00' before issuing another PRTOV.

If the device specified on the DD statement is not for a directly allocated printer, no action is taken.