The effect of coding the fc parameter

The feedback code is the last parameter of all Language Environment callable services, and the second to last parameter of all Language Environment math services. COBOL/370 programs must provide the feedback code parameter in each call to a Language Environment callable service; C, C++, Enterprise COBOL for z/OS, COBOL for OS/390 & VM, COBOL for MVS & VM, and PL/I routines do not have to do so. (See z/OS Language Environment Programming Reference for information about how to provide the feedback code parameter in each HLL.) When the fc parameter is provided and a condition is raised, the following sequence of events occurs:

1. The callable service in which the condition occurred builds a condition token for the condition. The condition token is a 12-byte representation of a Language Environment condition. Each condition is associated with a single Language Environment runtime message.
2. The callable service places information into the ISI, which might contain the following:
   • A timestamp
   • Information that is inserted into a message associated with the condition

     For example, you can use the CEEBLDTX utility (see Creating messages) or the CEECMI callable service (see z/OS Language Environment Programming Reference) to generate message inserts. Routines signaling a new condition with a call to CEESGL should first call CEECMI to copy any insert information into the ISI associated with the condition.

3. If the severity of the detected condition is critical (severity = 4), it is raised directly to the condition manager. Language Environment then processes the condition, as described in Condition step.
4. If the condition severity is not critical (severity less than 4), the condition token is returned to the routine that called the service.
5. When the condition token is returned to your application, you can use the condition token in the following ways:
   • Ignore it and continue processing.
   • Signal it to Language Environment using the CEESGL callable service.
   • Get, format, and dispatch the message for display using the CEEMSG callable service.
   • Store the message in a storage area using the CEEMGET callable service.
   • Use the CEEMOUT callable service to dispatch a user-defined message string to a destination that you specify.
   • Compare the condition token to one that is known to you so that you can react appropriately. You can test the condition token for success, equivalence or equality.

   See z/OS Language Environment Programming Reference for more information about Language Environment callable services.