Re: lifetime of a static variable

[Jim Langston <jimlangston@xxxxxxxxxxxxxxxx>]

Ahh, yes, I see.  You are using the static variable as a state variable.
I have done this kind of things in other programs, and I've always found
it best to be able to call the procedure with a reset variable to initialize
things when I wanted them to.

Something like

alwaysfalse('Reset')
if alwaystrue AND alwaysfalse('') and alwaysfalse('')
although this is not that clean.

Something else I would do would be to use a global variable instead of
passing something as a parameter.  Such as:

GL_Reset = TRUE
if alwaystrue AND alwaysfalse AND alwaysfalse

then have alwaysfalse do something like:

if GL_Reset = TRUE  (or Parm(1) = 'Reset')
  GL_Reset = FALSE
  ST_BeenHere = FALSE
EndIf

but this comes from my paranoia of not expecting any compiler to initialize
my variables correctly if at all.  I would initialize them in code.

I think what you are trying to do is a viable and meaningful use of static
variables, and in your particular case I agree, this is an undesirable side
effect in this case that has to be worked around.

Just a curiosity question, but are there Global Static variables?  By definition
Global Variables generally are static.  That would be useful in this case.

GL_BeenHere = FALSE
if alwaystrue AND alwaysfalse AND alwaysfalse

Regards,

Jim Langston

Joel Fritz wrote:
> 
> If I compile a program actgrp *caller and run it in the default activation
> group, the static variable's lifetime is the job.  This leads to what I
> thought of as unexpected results.
> 
> The particular thing I was doing was using a static variable as a flag to
> differentiate between the first call and succeeding calls to a procedure
> defined in the main program.  I know there's other ways to do it; it just
> seemed like a reasonable thing to do.
> 
> I wrote a simple program to demonstrate short circuit evaluation of things
> ANDed together and wrote a procedure that always returned false.  It had a
> static counter that was incremented each time the procedure was called.  If
> the counter was greater than 1 the procedure wrote a line to a print file.
> 
> I called the procedure like this:
> 
> if alwaystrue AND alwaysfalse AND alwaysfalse
> 
> The print file will have the line from alwaysfalse only if it's executed a
> second time.  Works as expected the first time, not the way I expected the
> second time.  I know better now.
> 
> > -----Original Message-----
> > From: Jim Langston [mailto:jimlangston@conexfreight.com]
> > Sent: Wednesday, November 15, 2000 8:20 AM
> > To: RPG400-L@midrange.com
> > Subject: Re: lifetime of a static variable
> >
> >
> > If you don't want static variables to retain their values during the
> > lifetime of the activation group, just what are you using them for?
> >
> > Otherwise, just use "normal" variables.
> >
> > Regards,
> >
> > Jim Langston
> >
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