longjmp()/setjmp() difference between gcc 3.3 (Apple) and gcc 3.4.x

[Mike Stump]

On Jan 27, 2005, at 1:41 PM, Remy X.O. Martin wrote:
> What I'd need would be a magic function like 
> PointerToValidAddress(void *ptr) which returns False if ptr doesn't 
> point to a memory location I can read/write.

This is trivial enough on a real OS, but, this is an OS question.

Meta point, this list is not for asking how do I write programs.  That 
is off-topic.

> In absence, what is the best way to avoid a crash when accessing 
> memory through a received --invalid-- pointer?

If you design your system so that you can validate pointers:

map<void *, kind> m;

pointer_lives (void *p, KIND k) {
     m[p] = k;
}

pointer_dies (void *p) {
     m[p] = dead;
}

bool valid_pointer (void *p, KIND k) {
     reeturn (m[p] == k);
}

you can trivially check them before use.