Re: *Zeros

["Rory Hewitt" <roryhewitt@xxxxxxxxx>]

Scott (and Jerry)

Another example of this kind of thing is if you try the following 2 lines of
code (assuming String is a 10-byte character variable):

String = *all'A';
String = 'B' + *all'A';


The first line is fine and would fill the String variable with 'AAAAAAAAAA'.
However, the program won't compile if you include the second line - in this
case, you'll get RNF7421 and RNF7416 errors (non-compatible operands). You'd
think that it should give you 'BAAAAAAAAA'....

Pesky intermediate operands :-)

Rory (http://www.linkedin.com/in/roryhewitt)


On 1/22/07, Scott Klement <rpg400-l@xxxxxxxxxxxxxxxx> wrote:
> Hi Jerry,
>
> > So I'm thinking (always dangerous), "Oh, *Zeros is a character field."
> > But, then, I remembered another line in this same program (and similar
> > lines in tons of other programs:
> > w#ladj = *Zeros;
>
> Hmmm...When I think of *Zeros, I don't think of it as being the same thing
> as the number 0.
>
> You see, *Zeros is neither character nor numeric.  *Zeros is a special
> value that tells the computer to fill the entire field (no matter what the
> data type) to zeroes. The compiler may generate different code,
> depending on the data type.
>
> What sort of code would it generate when it's only one of many operands in
> an expression?  That's where it gets murky.  There's no field to set to
> all zeroes, is there? It's an expression, not a simple assignment where
> there's a particular field to set.
>
> You have this:
>
>    w#ladj = *Zeros - dlsqty * dlstks;
>
> I know it means "fill the whole field with zeroes" but there isn't really
> a field for it to fill!  I suppose it might fill the intermediate result
> with zeroes before moving on to the next step...  But, I don't find it
> intuitive.
>
> Anyway...  I don't have a solution (other than using 0 in place of
> *Zeroes, which you've already done) but I thought you might find this
> perspective interesting.
>
> --
> Scott Klement http://www.scottklement.com