Programming considerations

The exits must follow standard linkage conventions. They must save the registers on entry and restore the registers when they return. The exits must be reentrant, refreshable, and reusable. The exits are not APF-authorized.

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 TEST 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 TEST 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 new subcommand buffer (parameter entry 11)
Set return code 0 and return control to TEST

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