What happens when an API exit runs?

The API exit routines to run are identified in stanzas (UNIX) or Registry entries (Windows). (For simplicity, we talk about the stanzas in mqs.ini and qm.ini; Windows users provide the same information using the WebSphere MQ Services snap-in.) The definition of the routines can occur in three places:

  1. ApiExitCommon, in the mqs.ini file, identifies routines, for the whole of WebSphere MQ, applied when queue managers start up. These can be overridden by routines defined for individual queue managers.
  2. ApiExitTemplate, in the mqs.ini file, identifies routines, for the whole of WebSphere MQ, copied to the ApiExitLocal set when a new queue manager is created.
  3. ApiExitLocal, in the qm.ini file, identifies routines applicable to a particular queue manager.

When a new queue manager is created, the ApiExitTemplate definitions in mqs.ini are copied to the ApiExitLocal definitions in qm.ini for the new queue manager. When a queue manager is started, both the ApiExitCommon and ApiExitLocal definitions are used. The ApiExitLocal definitions replace the ApiExitCommon definitions if both identify a routine of the same name. The Sequence attribute, described in Attributes for all stanzas determines the order in which the routines defined in the stanzas run.


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