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null pointersnull pointersPosted Mar 19, 2008 21:11 UTC (Wed) by quotemstr (subscriber, #45331)In reply to: null pointers by nix Parent article: Who maintains dpkg?
Can you name an example of a POSIX system for which the assumption does not hold?
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null pointers Posted Mar 19, 2008 21:47 UTC (Wed) by nix (subscriber, #2304) [Link] Any IA64 or PPC64-based systems. I think HPPA too but can't remember. (On both these platforms it so happens that data pointers are all the same size: but function pointers are larger... and yes this has exposed bugs in free software.)
null pointers Posted Mar 19, 2008 21:57 UTC (Wed) by quotemstr (subscriber, #45331) [Link] I don't think that's true. See the downthread comments on the same topic. I'd be interested in knowing what the specific bugs were.
null pointers Posted Mar 19, 2008 22:18 UTC (Wed) by nix (subscriber, #2304) [Link] If I could remember, I'd say. I'll have a dig.
null pointers Posted Mar 28, 2008 22:33 UTC (Fri) by anton (subscriber, #25547) [Link] On [PPC64 and IA64] it so happens that data pointers are all the same size: but function pointers are larger.Not on Linux-PPC64 (and probably not on Linux-IA64, either):
#include <stdio.h>
int main()
{
printf("%ld %ld\n", sizeof(void *), sizeof(int(*)()));
return 0;
}
prints
8 8
null pointers Posted Mar 29, 2008 1:08 UTC (Sat) by nix (subscriber, #2304) [Link] Oh. My memory is failing me and I can't read simulator source code, it seems. (I was *sure* they were examples of arches using a descriptor consisting of a data pointer combined with other stuff.)
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