At various times during your processing, you will need to compare CTOKENs. Typically, you will do this when JES signals an event for a CTOKEN and you need to find this token in your list so that you can take some kind of action based on the event.

To compare one CTOKEN to another, you must not simply compare the entire 80 byte values. This is because under certain JES processing, CTOKEN equality is based on a subset of the information in the CTOKENs matching while other information in the CTOKENs could be different. IBM provides a macro IAZXCTKN which you must use to compare CTOKENs. This macro determines which information in two CTOKENs is significant and compares just this information. The macro works in such a way that you never need to interpret any information inside the CTOKEN.

Depending on the return code from the IAZXCTKN macro, you can determine whether the two CTOKENs are the same, whether the first CTOKEN is less than the second one, or whether the second CTOKEN is less than the first one.

IAZXCTKN also provides a special comparison function. At certain times, JES signals events for an entire job. When this happens, the signal includes a job level CTOKEN. Using IAZXCTKN, you can determine whether a CTOKEN for a data set in which you are interested is covered by the job level CTOKEN that JES provides.

Job level CTOKENs contain no ordering information; therefore a job level CTOKEN can be considered by IAZXCTKN to be "equal" or "not equal" to another CTOKEN but never "greater" or "less" than another CTOKEN.

Refer to the book z/OS MVS Programming: Authorized Assembler Services Guide for information about using the IAZXCTKN macro.