Re: libunwind Cursor.step() return values

[Mark Wielaard <mark@klomp.org>]

Hi Phil,

On Thu, 2007-12-06 at 16:22 +0000, Phil Muldoon wrote:
> I see that step == 0 means no more or unknown frames. Further down the:
> 
> step = newCursor.step()
> 
> returns -1 in this case. What does that mean in this case?

A mixup of error codes... It is the result of an open() call passed
around as libunwind error code, which it isn't.
I am in the middle of rewriting this code.

But -1 could be returned in theory and then would mean:
UNW_EUNSPEC,                /* unspecified (general) error */
If so a new cursor couldn't be created, but that should still not lead
to the closing of fd 0 by some other code.

On irc (and a quick pair programming on vnc - that is actually pretty
cute) we tried to get the right error code across. Which seems to happen
(then -10 UNW_ENOINFO is returned), but that didn't fix bad file
descriptor closing. So I think it is unrelated, but actually some code
trying to shut down and messing up the tty.

Maybe one of the places found in the System.exit() bugzilla?
http://sourceware.org/bugzilla/show_bug.cgi?id=4299

Cheers,

Mark