SAP EXTERNAL PROCEDURE CALL GLOSRY documentation, setup help and example usage

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External Procedure Call
Procedure call from a different ABAP program of the same AS ABAP . The first time one of its procedures is called, the required program is loaded into the internal session of the calling program - if not already there - and, apart from in the case of class pools ,
event LOAD-OF-PROGRAM is triggered. See also Program Group .
ABAP_MORE_INFO