Cannot Use PERFORM form(prog)

You cannot declare an external subroutine using the syntax form(prog) in ABAP Objects.

In ABAP Objects, the following statement causes an error message:

PERFORM form(prog) ...

Correct syntax:

PERFORM form IN PROGRAM prog ...

Cause:

The PERFORM form IN PROGRAM prog has replaced the PERFORM form(prog) statement. The name declaration form IN PROGRAM prog (unlike form(prog)) allows you to declare dynamic program names using the form IN PROGRAM (name) variant. Conversely, the static form, form(prog)does not comply with standard ABAP semantics, in which the dynamic variant is differentiated from the static variant using parentheses.

Overview:

Replacement for Obsolete Statements ABAP Objects