Re: How to prototype CL modules

h
Hello Barbara

You wrote:
>You can do it in C with #pragma map:

>#pragma map (QMHSNDPM_opt1, "QMHSNDPM")     (I might have the syntax wrong)
>void QMHSNDPM_opt1 (parms);

That's no different from your original suggestion of multiple prototypes.  
You're simply 
doing a rename.  I can do that in RPG IV too.  What I meant was there is no HLL 
I am 
aware of that allows a prototype to define inter-parameter relationships.  And 
even in C 
I would have to define the prototype called QMHSNDPM_opt1 because the standard 
prototype 
just uses the ellipses to indicate optional extra parameters.  The RPG 
equivalent would 
be something like:

D QmhSndPgmMsg                  EXTPGM('QMHSNDPM')
 * Defines only parameter group one and all are required

D QmhSndProcMsg                 EXTPGM('QMHSNDPM')
 * Defines parameter groups one and two and all are required

D QmhSndProcMsgXlate            EXTPGM('QMHSNDPM')
 * Defines parameter groups one, two, and three and all are required

Then if I want to pass a pointer to the call stack entry I need a new lot of 
prototypes.  
Also, the moment you allow literals to be passed by using CONST you open the 
door for 
the user to stuff the intent (e.g., with the Call Stack Entry parameter).  I 
still like 
the parameter group idea :)

>I think that as much information should be put into the prototype(s) as
>possible.  I also think that the earlier a mistake is detected, the easier
>it is to fix.  Finding a mistake in parameters at compile time is better
>than finding it in unit test (especially if it's in the exception path that
>doesn't get hit until late in the testing).

I agree, but the programmer must still accept responsibility for ensuring the 
parameters 
are correct.  It is a little different if you are providing wrappers for the 
functions.  
Then you make the interface as simple as possible.  Of course, if we get a 
parameter 
group tag then we'll both be happy ....

Regards,
Simon Coulter.

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