Re: Error message procedure program

["Simon Coulter" <fbns@xxxxxxxxxxxxxxxxx>]

HEllo Buck,

You wrote:
>Ordinarily you would add the VALUE keyword to the parameter.  

CONST is generally a better choice because it makes it obvious that the 
parameter should not be changed.  Also, ALL AS/400 HLLs support passing 
by reference and CONST is a pass-by-reference mechanism.  VALUE has some 
advantages when passing numeric values by reducing the amount of space 
used in the stack but in most cases should be used only when interfacing 
to C functions.

>Unfortunately, CL can only accept calls by reference. 

Which is one reason why CONST is better because it allows 'constant by 
reference' parameters which CL supports.  This will allow RPG to pass a 
literal to CL and have it padded to the correct size by the compiler.

Note, however that the reverse situation (i.e., CL calling an RPG or 
COBOL procedure) is not quite so easy.  CL does not suport prototyping so 
it doesn't know that a short literal should be padded to say 50 bytes.  
In this case you should use OPDESC and OPTIONS(*VARSIZE) in the called 
procedure and determine how much data was passed by the caller.  (Or you 
could add an extra parameter for the length but that's just ugly -- 
especially in CL.)

Regards,
Simon Coulter.
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