[PD] What exactly is a "stack overflow" ?

[Andy Farnell]

By that reckoning bang-until would run itself out after a few seconds.
One of us is wrong. (I apologise in advance :)

What's going on?

Perhaps we can reach a reasonable compromise in source.
If you knew that an accidentally banged until would give up
after a couple of minutes it wouldn't be so bad.

On Wed, 19 Dec 2007 17:49:44 -0600
Russell Bryant <russell at russellbryant.net> wrote:

> Frank Barknecht wrote:
> > If people want to make sure to not be bitten by the endless loop, they
> > could just use 
> > 
> >   [inlet]
> >   |
> >   [b]
> >   |
> >   [f 1000000000000]
> >   |     [inlet]
> >   |     |
> >   [until]
> >   |
> >   [outlet]
> > 
> > as an abstraction called: [funtil] It will bang 1000000000000 times
> > unless stopped, which is more bangs for the bang than most people
> > would want.
> 
> It doesn't look like that would work.  The number of times to run is stored as
> an int, which on most systems is 4-bytes.  The maximum is a bit over 2 billion
> for a float input.  :)
> 
> Also, from looking at the implementation of [until], a simple bang until will
> stop after a complete overflow over the storage space in an integer, which is
> usually 4 billion and change.
> 
> (x_count is an int.)
> 
> static void until_bang(t_until *x)
> {
>     x->x_run = 1;
>     x->x_count = -1;
>     while (x->x_run && x->x_count)
>         x->x_count--, outlet_bang(x->x_obj.ob_outlet);
> }
> 
> --
> Russell Bryant
> 
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