Special considerations for Control-O

To enable Control-O to change or suppress subsystem commands (for example, commands for DB2 that start with the '-' character), the Control-O subsystem must be defined in the IEFSSNnn member BEFORE the definition of the target subsystems of these commands.

An exception to this rule is the interception of JES2 commands using the IEFJFRQ dynamic subsystem exit, instead of a Control-O subsystem. For more information, see the JCMDSSN parameter in Step 2.1 – Control-O operational parameters.