Event Blocks in Executable Programs
When you run an executable program, the program flow is controlled by the external events in the ABAP runtime environment. The following diagram shows the sequence of the events:
The events in the gray box are only processed if you have entered a logical database in the program attributes. The AT SELECTION-SCREEN event is only processed if a selection screen is defined in the program or the logical database linked to the program. The other events occur when any executable program is run. (See also
Processing Blocks in ABAP Programs.)As well as these events, there are others that can, as in other ABAP programs, occur when a list is created (TOP-OF-PAGE, END-OF-PAGE), and in interactive lists (AT LINE-SELECTION, AT USER-COMMAND). For more information about these events, refer to
Lists.If you want to handle an event, you must define the corresponding event block in your program. If you do not define the event block, there is no reaction to the event.
Description of Events Leaving Event Blocks.