What is the use of at-exit in mudule pool

Question

hi
what is the use of at-exit in mudule pool. what is the use when we keep the function type as 'E' for a function code

Answer 1

AT EXIT-COMMAND lets you call a module before the system executes the automatic fields checks.
Automatic field checks can be avoided through AT EXIT-COMMAND, which works exactly the same way as CANCEL works from standard tool bar.  In the R/3 screen, if your want to quit the processing of that particular screen without entering the mandatory fields then user can click the CANCEL button, same functionality can be incorporated in the user defined transaction by usine AT EXIT-COMMAND.  This module can be called before the system executes the automatic field checks.
Code for AT EXIT-COMMAND in flow logic and in module pool program can be written as follows.
In Flow Logic:
PROCESS AFTER INPUT.
MODULE EXIT AT EXIT-COMAND.
In Module Pool Program:
MODULE EXIT.
case okcode.
when 'EXIT'.
leave to screen 0.
ENDMODULE.
To achieve this kind of functinality, the pushbutton or menu item should be assigned a function type 'E' (Exit).  It tells the system to process this particular module before carrying out any field checks.
Rewards if useful.