RE: How to create my own built-in functions

[Scott Klement <klemscot@xxxxxxxxxxxx>]

On Mon, 17 Jul 2000, Buck Calabro wrote:

> You could certainly change the prototypes to "N" (indicator) if you wanted
> to.  I basically cribbed this quickie example from some existing code which
> used integer.    You can't use the form above with an integer data type -
> unlike C, RPG IV doesn't overload "Indicator" or "boolean" data types onto
> integers.  

I personally like to use integers as return codes.   Sure, if your goal is 
specifically to return a boolean value, an indicator would be better.  
For example something like IsDataValid()  would be better returning a
boolean value...

But with an integer you can return a lot of different things.  Lets say
for example, you're doing a  "RtvOrder()"  subprocedure.   You might have
a return value of "1" to mean it found the order, "0" that it couldn't
find the order (Which isnt necessarily an error) or "-1" to indicate that
that there was some sort of error.  (file not found, file damaged, etc)

I also (usually for debugging purposes) like to return different values to
help pinpoint where an error occurred.   Such as -1, -2, -3, -4 each
indicating a different error.   This way, my programs that don't care
WHICH error occurred can just check    if MyProc()<0   whereas those that
do care which error occurred can save that return code and act upon it.

So, although the indicator return value has its place -- its not NEARLY as
versatile as returning an integer is... thats my 2 cents on that :)


> 
> Also, as Scott pointed out, I have a dopey bug (I defined rc as unsigned
> integer when it should be SIGNED integer.  Thanks Scott!  Extra eyes make
> for fewer bugs!  I tested for the "successful" condition but not for the
> "failed" condition.  I gotta start paying closer attention to my own sig!)
> 

Hey... not a problem... thats the kind of mistake that everyone makes once
in awhile :)



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