In order to activate the compiler user exit, you must specify the EXIT compile-time option. For more information on the EXIT option, see EXIT.
The EXIT compile-time option allows you to specify a user-option-string which specifies the DDname for the user exit input file. If you do not specify a string, SYSUEXIT is used as the DDname for the user exit input file.
The user-option-string is passed to the user exit functions in the global control block which is discussed in Structure of global control blocks. Please refer to the field "Uex_UIB_User_char_str" in the section Structure of global control blocks for additional information.