Writing exits for the TSOLIB command

TSO/E users issue the TSOLIB command to dynamically link to different versions of load module libraries while in their TSO/E session. TSO/E searches these libraries before those specified in the user's logon procedure. Therefore, the users' logon procedures can be kept simpler. Also, system and application programmers do not need to maintain different user IDs just to switch to different versions of load modules.

TSO/E provides initialization and termination exits that you can use to customize the TSOLIB command. These exits receive control during TSOLIB command processing, as follows:

The initialization exit receives control before the TSOLIB command processor invokes the parse service routine to syntax check the input parameters.
The termination exit receives control just before the TSOLIB command terminates processing.