Exit Routines

The DCB macro can be used to identify the location of a:
  • Routine that performs end-of-data procedures
  • Routine that supplements the operating system's error recovery routine
  • List that contains addresses of special exit routines.

Table Table 1 lists the OS/MVS exit routines that CMS can simulate.

Table 1. OS/MVS Exit Routines Simulated in CMS
Exit Routine When Available Where Specified
End-of-data-set When no more sequential records or blocks are available. EODAD operand
Error analysis After an uncorrectable input/output error SYNAD operand
DCB open When opening a data set EXLST operand and exit list
User Label Exits When processing SUL or AUL tapes. EXLST operand and exit list
Block count After unequal block count comparison by end-of-volume EXLST operand and exit list
DCB Abend When an abend condition occurs in OPEN, CLOSE, or end-of-volume routine. EXLST operand and exit list

Following is a description of these exit routines. For more details, see the DFSMS Macro Instruction for Data Sets.