The same as for
CALL FUNCTION func.
Calls the function module func, which can be activated. func
must be a 3-character literal (e.g. '001')
In line with SAP's enhancement concept, function modules are delivered empty and must be implemented by the customer (the transactions used are SMOD at SAP and CMOD at the customer's).
The interface and call location are both defined by SAP.
The customer can use Transaction CMOD to activate the function
module. The final name of the function module is compiled from
EXIT_, the name of the module pool where the function
module is called, and the name func. For example, the statement
"CALL CUSTOMER-FUNCTION '001'" in the module pool SAPMS38M calls
the function module EXIT_SAPMS38M_001.
If you do not activate the function module with Transaction CMOD, any call to the function module has no effect at all. System fields in particular (for example, SY-SUBRC ) keep the value they had before the call.