Your Command Processor can provide a validity checking routine to do additional checking on a positional operand. Each positional operand can have a unique validity checking routine. Indicate the presence of a validity checking routine by coding the entry point address of the routine as the VALIDCK= operand in the IKJPOSIT, IKJTERM, IKJOPER, or IKJIDENT macro instructions. This address must be within the program that invokes the Parse Service Routine.

Parse passes control to the validity checking routine after it has determined that the operand is non-null and syntactically correct. If a DSNAME or USERID operand is entered with a password, parse passes control to the validity checking routine after first parsing both the userid or dsname and the password. If the terminal user enters a list, the validity checking routine is called as each element in the list is parsed. If a range is entered, the Parse Service Routine calls the validity checking routine only after both items of the range are parsed.