User exits

A user exit point (normally referred to as a user exit) is a place in a CICS® module at which CICS can transfer control to a program that you have written (a user exit program), and at which CICS can resume control when your exit program has finished its work. You do not have to use any user exits, but you can use them to extend and customize the function of your CICS system in accordance with your own requirements.

For example, you might want to log the completion of each task or take some action if a task completes abnormally. To do this, you write a user exit program that is to be invoked at the task termination user exit, and you set the UserExitNumber attribute in the Program Definition of the program to '15', the number that identifies the task termination user exit.

Each user exit has a unique number and name, and is normally referred to by its user exit number, which forms the last three characters of its name.

          UEcccnnn

where ccc is the module identifier of the CICS component that invokes the user exit program and nnn is the user exit number, padded to a length of three characters with leading zeroes.

Table 1 shows the numbers and names of the user exits:

For information about standard definitions and data types for user exits, see Standard definitions and data types.