Type 07 JFCB Exit List Entry

The type 07 JFCB exit list entry allows you to perform a variety of tasks, as described in the following text.

The format of the type 07 JFCB exit list entry is:

Table 1.
Hexadecimal Code (High-Order Byte)	Contents of Exit List Entry (Three Low-Order Bytes)
07	Address of a 176-byte area required if the RDJFCB or OPEN (TYPE=J) macro instruction is used.

The virtual storage area into which the JFCB is read must be:

Located within the user's region
On a word boundary
At least 176 bytes long.

Requirement: Users running in 31-bit addressing mode must ensure that this area is located below 16 MB virtual. Each exit list entry must be 4 bytes long. The system recognizes only the first occurrence of an exit list entry code. Indicate the end of the exit list by setting the high-order bit in the entry code byte to 1.

The DCB can be either open or closed when this macro instruction is executed. If accessing concatenated sequential data sets and the DCB is open, the RDJFCB routine reads the JFCB for the current data set. In all other cases, the RDJFCB routine reads the JFCB for the first or only data set.

If the RDJFCB routine fails while processing a DCB associated with your RDJFCB request, or you do not provide a virtual storage address in the three low-order bytes of the exit list entry, your task is abnormally terminated. None of the options available through the DCB ABEND exit, as described in z/OS DFSMS Using Data Sets, are available when a RDJFCB macro instruction is issued.