RE: How to create my own built-in functions

[Buck Calabro <buck.calabro@xxxxxxxxxxxxxxxxx>]

Joel Stone wrote using HTML:

>I want to create my own built-in functions, 
>to be used in any ILE program.

AMEN!

>I think I want a combination of sub-procedures, 
>binding directories, service programs, activation 
>groups, etc.
>
>I cant seem to find an article that puts them 
>all together in a VERY simple example.  
>Does anyone know of such an article in 
>Midrange Computing or News/400?

There have been scads of articles; I'm not certain there exists one very
simple example of all the elements you mentioned.  There's a lot of
complexity there!  Aside from the oft mentioned Redbook (Who knew you could
do that with RPG?) there may not be a single repository of that information.

It seems that the typical example of a user defined function is the call to
QCMDEXEC.  Being me, I will avoid that!:

 * QRPGLESRC mbr(DSPLY)

H debug dftactgrp(*no) actgrp('QILE') option(*srcstmt: *nodebugio)    
 * dbgview(*list)                                                     
                                                                      
 * Display a message to the user                                      
                                                                      
D   rc            s             10u 0                                 
                                                                      
D ShowMsg         pr            10u 0                                 
D   MsgText                     50    const                           
D   MsgQueue                    10    const                           
                                                                      
C                   eval      rc = ShowMsg('Test': 'BUCK')            
C                   eval      *inLR = *On                             
                                                                      
P ShowMsg         b                   Export                          
D ShowMsg         pi            10u 0                                 
D   MsgText                     50    const                           
D   MsgQueue                    10    const                           
                                                                      
D   rc            s             10u 0                                 
                                                                      
C     MsgText       Dsply     MsgQueue                             99 
                                                                      
C                   If        *In99 = *On 
C                   Eval      rc = -1     
C                   Else                  
C                   Eval      rc = 0      
C                   EndIf                 
                                          
C                   Return    rc          
                                          
P ShowMsg         e                       

This compiles with option 14 off of PDM, so it qualifies as a simple example
- no special binding, etc. but it shows the procedure prototype (the PR),
the actual procedure code (flanked by the P specs, including the PI).  It
also shows local variable usage (rc within the procedure) and how to invoke
the function (eval rc=ShowMsg...)

The only special thing I do is to use the Windows "copy" function to copy
the "dbgview(*list)" before I exit SEU.  When I compile, I put 14 in the
option field, newline to the command line and "paste" it there before
pressing Enter.  That way I don't have to prompt every compile and I can
compile it on any machine without having to modify CRTBNDRPG.

As I said, this is a simple enough example.  If you want to have some fun
with it, we can turn this into a mini-tutorial on how to learn ILE.  (This
example is more like "How to learn RPG IV.")

Buck Calabro
Aptis; Albany, NY
"We are what we repeatedly do.
 Excellence, then, is not an act, but a habit." --Aristotle


Billing Concepts Corp., a NASDAQ Listed Company, Symbol: BILL
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