Re: *entry and PR with same program as EXTPGM

[Vern Hamberg <vhamberg@xxxxxxxxxxx>]

In normal subprocedure usage, you define the prototype first, then write 
out the procedure itself, using the PI - procedure interface. It is the 
PI that gives you your actual variables - those in the PR are just for 
readability - names there are not required, just the data type and 
modifiers.

Now for a MAIN procedure - not a subprocedure - the prototype (PR) and 
the PI end up close together, or can - at any rate, they need to be 
above all other code. So the main body is really now a procedure but it 
does not use the P-specification.

The greater flexibility for defining parameters is a plus - will most 
use it much? Maybe not for awhile, but you can't do much with PLISTs, as 
compared to prototypes.

MHO
Vern

Jerry Adams wrote:
> Chamara,
>
> In the situation you illustrated, the ExtPgm( ) isn't really required.  But obviously doesn't cause any problems.  As Adam (I think) said, the PR definitions should be in a copy book somewhere.  So in the copy book the ExtPgm( ) keyword makes sense since it may be a candidate for inclusion in another program that calls this one.
>
> I don't know for a fact, but I doubt there is any advantage in using either method to define the parameters (*Entry list).  My bet is that it's the PI structure that defines the PList and that the PR is just along (syntactically) for the ride.  If that's true (big IF), the compiler will generate the same code for both.
>
> The "advantage" is in the eye of the beholder.  Like someone else said, I hated using PList when I moved to free format.  When Jon told me about this method at a COMMON session,  I jumped on it because, well, it just looks neater.
>
> Jerry C. Adams
> IBM System i Programmer/Analyst
> --
> B&W Wholesale
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>
> -----Original Message-----
> From: rpg400-l-bounces@xxxxxxxxxxxx [mailto:rpg400-l-bounces@xxxxxxxxxxxx] On Behalf Of Chamara Withanachchi
> Sent: Wednesday, April 15, 2009 8:00 AM
> To: RPG Programming on the AS400 / iSeries
> Subject: *entry and PR with same program as EXTPGM
>
> Hi all,
>
> Can someone clarify me what is the different between *ENTRY and coding a procedure as the same name of the program and using EXTPGM keyword
>
> Ex;
>
> Abcpgm           pr               extpgm('ABCPGM')
>   Parm1                    10a
>
> Abcpgm           pi
>   Parm1                    10a 
>
>
>
> Regards,
>
> Chamara Withanachchi
> IBM Certified Power System Expert
> RPG Programmer 
> (owner of www.rpgiv.info)
>  
> WWW.RPGIV.INFO
> Mob: +971 50 5698644
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>
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>