The exit must follow standard linkage conventions. It must save the registers on entry and restore the registers when it returns. The exit must be reusable, reentrant, and refreshable.

Exit processing is determined by setting various control switches and return codes. For more information about the control switches and parameter list, see Entry specifications. For information about the return codes, see Return specifications.

By default, the exit gets control only when the first JOB statement is read or generated. The exit can process other types of JCL statements by setting the different control switch bits in byte 0 of word 5 of the parameter list.

The SUBMIT command processor sets control switch bits in bytes 2 and 3 of word 5 to indicate to the exit the type of current statement it is passing. The exit can check these bits to determine the type of statement and whether the statement is a continuation of an operand or a continuation of a statement itself.

Word 6 of the parameter list is for the exit's use. The exit can use the bits in word 6 to keep track of its processing. SUBMIT does not change word 6 between calls to the exit. The exit can set a bit to indicate a certain condition and then check that bit when it receives control again. In this way, the exit can determine what processing it did during the last invocation and what processing it is to perform based on the bit settings.

The exit can also use the return codes to determine how statements are processed and when the exit receives control again. For example, if the exit has finished processing the current statement, it sets a return code of 0. The SUBMIT command processor then processes that statement and continues with the next one. If the exit wants to receive control again to either continue the current statement or add a new statement, it sets a return code of 4. Use return code 8 to display a message and return code 12 to display a message and get a response.

To format the parameter list and assign symbolic names to return codes, use the IKJEFFIE mapping macro instruction. IKJEFFIE creates two assembler DSECTs named IEDSECTD and IESUBCTD. For the format of each DSECT, see .

IKJEFFIE IETYPE=SUBMIT

After establishing addressability with each DSECT, you can refer to the DSECT fields by name.