Re: Continuations: possible newbie question

[Matt Hellige]

[Neil Jerram <address@hidden>]
> >>>>> "Matt" == Matt Hellige <address@hidden> writes:
> 
>     Matt> Well, at this point it definitely seems to be a bug.
> 
> I tried your original code in my copy of stable branch Guile CVS
> (i.e. 1.6.x), and it worked as (you) expected.
> 
> So either this has been fixed, in which case you could try the just
> released 1.6.1, or it is something trickier to pin down, in which case
> what platform are you using etc.?
> 

Interesting. At first 1.6.1 showed the same behavior, but I got
suspicious that it was something about my config, and tried rebuilding
with different optimization settings. The problem went away.

I *believe* that the significant change was from -O3 to -O2. Based on
the little that I know about how guile is implemented, this doesn't
surprise me too much: I assume that the optimization somehow broke
guile's stack inspection magic. On the other hand, that could be way
off. As I said, I've been using guile (and scheme) for less than two
weeks now.

In any case, this is almost certainly not a bug in guile, but is it a
known issue with building? Is it documented anywhere that optimization
beyond -O2 may break guile? I couldn't find it in INSTALL, or anywhere
else, but I may have missed it. Perhaps it should be mentioned, as the
resulting behavior is definitely a bit mystifying. :)

On the other hand, I'll probably still not end up using this technique
to implement my call-backs, given the performance penalties and so on.
I hope I can just shuffle things around a bit in my native code...

Thanks very much for your help!

Matt

-- 
Matt Hellige                  address@hidden
http://matt.immute.net