Re: Infinit loop in /free

[Scott Klement <klemscot@xxxxxxxxxxxx>]

> But to the question at hand, which is, does "DO *HIVAL" loop an
> indeterminate number of times? Well, technically, yes. At least, if you
> compile using TRUNCNBR(*YES), which is the default. By default, decimal
> arithmetic on fixed-form calcs (but not the expression calcs) truncates
> on overflow. That means that when the implicit loop index reaches the
> value of *HIVAL, rather than overflowing when it's incremented again, it
> gets truncated. Thus, the implicit loop index never exceeds the limit,
> and the loop keeps churning away. (At least until the operator notices
> and cancels the job!)

Wow... that's obscure.   I can't believe people would write code like
this!  I mean, if we didn't have the ability to get answers from the
compiler team, how would I have EVER known that "DO *HIVAL" was going to
loop infinitely?

It sure isn't obvious.


> But in my opinion, "DO *HIVAL" is bad style. Other techniques, like the
> "DOU FOREVER;" mentioned by someone else, are preferable.

Amen!  "DO *HIVAL" is very bad style.  It's comparable to multiplying a
numeric date field by 100.0001.

I like "dow 1=1" because it's obvious.  Anyone who reads that code knows
that 1 will always be the same as 1, so the loop will go on forever.
I also like "dow forever" or "dou forever"  it may not be as obvious how
the code works as "dow 1=1" but it's self-documenting and efficient...