Re: [9fans] thornbird (another xscreensaver hack)

[jmk@plan9.bell-labs.com]

On Fri Jun 21 18:45:41 EDT 2002, andrey@lanl.gov wrote:

> > Reminder: malloc does not return zeroed storage.
> > Either zero it on return or use mallocz.
>
> it's not my code -- i'm simply fixing the X-related stuff, adding
> main(), drawing and that's all...  haven't really debugged the actual
> xscreensaver hack...
>
> unless malloc() behaves differently than the linux/unix ones i simply
> didn't think there may be a problem -- it works there, why shouldn't
> it here?

"it works there, why shouldn't it here?" - Because it's different.
The crash trace which someone posted was because Plan 9 malloc does
not return zeroed memory and the code does a check to see whether
pointers stored in that memory are NULL or not, and tries to free
the non-NULL ones. I don't believe there is any requirement in the
C standard (although I haven't checked) for the returned memory to
be zeroed. A check of the 2 non-Plan 9 systems I have handy (Linux,
Irix) show one will zero the memory and one won't.