IBM offers default versions of CEEBXITA and CEEBINT. You can use the IBM-supplied default version of either exit, or you can customize CEEBXITA or CEEBINT for use on an installation-wide basis. When CEEBXITA or CEEBINT is linked with the z/OS® Language Environment® initialization/termination library routines during installation, it functions as an installation-wide user exit.
Finally, you can customize CEEBXITA or CEEBINT yourself for use on your application. When CEEBXITA or CEEBINT is linked in your program, it functions as an application-specific user exit. The application-specific exit is used only when you run that application. The installation-wide assembler user exit is not executed.
To obtain an application-specific user exit, you must explicitly include it at bind time in the application using a binder INCLUDE control statement. Any time that the application-specific exit is modified, it must be relinked with the application.
The assembler user exit interface is described in Assembler user exit interface. The HLL user exit interface is described in High level language user exit interface.