Due to the disadvantages that SAP faced in the user exits (data can be interpreted erroneously), SAP introduced the concept of Customer Exits.
- The R/3 enhancement concept allows you to add your own functionality to SAP’s standard business applications without having to modify the original applications. SAP creates customer exits for specific programs, screens, and menus within standard R/3 applications. These exits do not contain any functionality. Instead, the customer exits act as hooks. You can hang your own add-on functionality onto these hooks.
- CUSTOMER EXITS are FUNCTIONS basically function modules, so they are called using CALL FUNCTION (or more exactly CALL CUSTOMER FUNCTION).
- Inside the function module (customer exit) you can only access your import/export/changing/tables parameters.
- Customer exits are more restrictive ensuring you in changing/using of any parameter of the FM, will never lead to inconsistency.
- In Customer-exit no access key is needed.
Also since the custom coding done as part of these customer-exits is located away from the original SAP code, the maintenance is easier than user-exits.