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Buggifying critical core modulesBuggifying critical core modulesPosted Mar 19, 2008 15:19 UTC (Wed) by tjc (guest, #137)In reply to: Buggifying critical core modules by quotemstr Parent article: Who maintains dpkg?
> the bit pattern of the pointer is going to be same no matter what --
> provided you pass an actual pointer.
This took me by surprise:
int main(void)
{
int n;
void *p = &n;
printf("%p\n", p);
p++;
printf("%p\n", p);
return 0;
}
I thought incrementing a void pointer would cause a compiler error (or at least a warning),
but it seems to treat it as a char pointer and increment it by one byte on my system (gcc
4.1.2 on Solaris).
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Buggifying critical core modules Posted Mar 19, 2008 15:26 UTC (Wed) by dw (subscriber, #12017) [Link]
A GCCism:
-Wpointer-arith
Warn about anything that depends on the ``size of'' a
function type or of "void". GNU C assigns these types a
size of 1, for convenience in calculations with "void *"
pointers and pointers to functions.
Buggifying critical core modules Posted Mar 20, 2008 18:34 UTC (Thu) by dododge (subscriber, #2870) [Link] The lesson being: when you run "gcc" with no options, it does not compile the C language, but rather the "GNU C" language. GNU C bears a strong resemblance to C but has many additional and alternate semantics. If you're trying to write portable code and you want gcc to follow Standard C rules, you have to explicitly request it. I normally use, at a minimum: -std=c99 -pedantic -Wall -Wextra
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