Finding Actual function module for a Function Exit

It is common to find customer exits in SAP’s code and Function modules, to accommodate customer specific business rules in SAP provided applications. These exits sometimes are in the form:

Call Customer-Function ‘xxx’, where ‘xxx’ is usually a number. So, how do we know what the actual function module is, where we should put our custom code?

Here is a screen shot of a function module with customer exit:

To find out the actual function module, we will need to know what the main program name is. You can go to the main program using the menu item GO TO –> Main Program

Now, our customer exit name would be:

EXIT_<Progam Name>_<XXX>,

Where    
<Program_Name> is the main program name     
<XXX>                  is the number next to “Customer-Function”

In this example function module, the main program was : SAPLHRBEN00GENERAL.

Hence, our customer exit will be  
EXIT_SAPLHRBEN00GENERAL_022