Programming considerations

The exits must follow standard linkage conventions. They must save the registers on entry and restore the registers when they return. The exit must be reentrant, refreshable, reusable, and reside in an APF-authorized library. It is inadvisable for the exit to have APF authorization unless it is designed also to be called as the entry point for a job step program.

The exits can use any of the TSO/E service routines. For a description of the service routines, see .

In some cases, you may not need to write a termination exit. This depends on:

Whether the processing that the subcommand initialization exit performs requires a termination exit to perform clean-up activities
How you use the exits to customize TESTAUTH subcommand processing

If the subcommand initialization exit obtains a system resource, you must write a subcommand termination exit to free the resource. For example, if the initialization exit obtains storage to return a new subcommand buffer to the TESTAUTH command processor, you must provide a subcommand termination exit to free the storage.

The initialization exit can change subcommand operands using the subcommand buffer. The exit checks the subcommand buffer it receives and determines whether to change any operands. To change the operands, the exit must:

Obtain storage for a new subcommand buffer
Build the new subcommand buffer
Update the key, length, and data fields for the address of the new subcommand buffer (parameter entry 11)
Set return code 0 and return control to TESTAUTH

For more information about the parameter entries, see TSO/E standard exit parameter list. For more information about the format of the subcommand buffer, see Command buffer.