Re: Passing params between modules

[boldt@xxxxxxxxxx]

Jocke wrote:
>Im rather new at ILE-RPG and have just started doing some module
>programming. Now I want the main program to call another module
>with parameters and get a result back.
>
>After I read the manuals I beelive CALLB is the way to call other modules
>in the program but whats the best way to exchange data ?
>
>Should I use *ENTRY PLIST or go with the keyfunctions IMPORT / EXPORT fields ?

Forget about CALLB (and CALL while you're at it).

Go back to the manuals and read up about CALLP, procedures,
and prototypes.  This is the preferred way to do things in
ILE RPG IV for many reasons:  CALLP allows you to use
free-form expressions.  You can have return values from
procedures.  You can pass parameters by value, which is
safer than passing by reference.  Parameter types on CALLP
are checked against the prototype definitions, which can
catch coding errors at compile-time.  CALLP allows either
bound or dynamic call (depending on the prototype). ...

(If we ever decided to "deprecate" certain opcodes, CALL
and CALLB would certainly be on that list!)

Avoid using IMPORT/EXPORT for passing values to procedures.
Instead, parameter passing is much clearer and easier to
understand.

Cheers!  Hans

Hans Boldt, ILE RPG Development, IBM Toronto Lab, boldt@ca.ibm.com


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