IBM Natural Interview Question:

How do you pass data from a Natural Program to an External Subroutine? Can it share the LDA of Program as in Internal Subroutine?

Submitted by: Administrator

Parameters can be passed with the PERFORM statement from
the invoking object to the
external subroutine. These parameters must be defined
either in the DEFINE DATA PARAMETER
statement of the subroutine, or in a parameter data area
used by the subroutine.
An external subroutine can access the global data area used
by the invoking object.
In addition, an external subroutine can have its own local
data area, in which the fields that are to be used
only within the subroutine are defined.
However, an external subroutine cannot have its own global
data area.
Submitted by: Administrator

There is no necessity to pass variables seperately in a SUBROUTINE as it's a part of Program. You can access the variable between call calling module and EXternal subroutine using GDA.You can't pass varibles using PDA. PDA is used only for SubProgram
Submitted by: Rajeev Kumar Boddeapalli