Re: *Zeros -- RPG400-L

Scott,

I agree: the nature of the beast is a little murky. Usually I just useit to set a field's value to, well, zeros. Though I have, asillustrated (*Zeros ADD X Y) used it in place of, say, MOVE X Yin fixed-format code. Which the compiler likes just fine.My guess is that it is either EVAL that doesn't like it in this context(though EVAL w#ladj = *Zeros compiles just fine), or they (thecompiler writers) grandfathered it into the ADD, SUB, etc., op-codessince I've used it in RPG II, III, and IV as illustrated by the ADD example.


I guess "murky" is as apt as "strange" in this case .-) .

        * Jerry C. Adams
*IBM System i5/iSeries Programmer/Analyst
B&W Wholesale Distributors, Inc.* *
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Scott Klement 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 thingas 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 inan expression? That's where it gets murky. There's no field to set toall zeroes, is there? It's an expression, not a simple assignment wherethere'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 reallya field for it to fill! I suppose it might fill the intermediate resultwith zeroes before moving on to the next step... But, I don't find itintuitive.
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 thisperspective interesting.