Return and Reason Code Values

The exit routines can indicate one of four return codes and one of two reason codes associated with return code 8.

Return Code	Reason Code	Meaning
0	0	Label the tape.
4	0	I don't care.
8	0	Do not label the tape.
8	4	Don't label this tape, mount a new tape and label it.

Return code 0 notes:
When return code 0 is returned by the exit routine, the following fields, which contain values to be used in labelling the volume, may be modified:
- INXRQVOL, volume serial number
- INXRQOWN, owner ID
- INXRQACC, access code
Changes to any other fields are ignored.
Return code 4 notes: The exit routine return code is set to a value of 4 before each exit routine is called.
Changes to any fields are ignored.
Return code 8, Reason code 0 notes:
It is important to note that once a no label indication is set, there is no way to override it. The volume will not be labeled.

Changes to any fields are ignored.
Return code 8, Reason code 4 notes:
When this return code and reason code is returned, the value in INXRQVOL must be changed. A mount for the volume indicated in this field is issued. All subsequent pre-label exit routines are passed the original volume serial, not the remount volume serial.

The post-label exit routines are not called for this volume.

When the remount is successfully processed and the actual volume is mounted, the pre-label exit routines are called again and the volume serial that has been passed into the exit routines is now the new volume serial.

Changes to any other fields are ignored.