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0 pointscbsmith9y ago0 comments

Oh, I was assuming a runtime that didn't do wraparound. If you are doing wraparound, you already have a ton of special case work you'd have to do.

But yes, you'd need logic for pointer comparisons as well.

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int_19h9y ago

Wouldn't it be very unusual for an environment to not do wraparound? I mean, on assembler level, pointers are just integers, and pretty much everything does wraparound arithmetics on those these days.

But, so far as I can see, this case (allocating at the very end of address space) is the only one where wraparound would matter for pointers.

And what would be the other option? If it's saturation, then your one-past-the-end pointer for the array at the end of address space would compare equal to pointer to last element...

cbsmithOP9y ago

It's pretty common to have stack and heap growing from opposite address ranges towards a central address space. That makes wrap around an unimportant feature that isn't worth the trouble.

Now, runtimes are increasingly adopting address randomization, which can change the rules about this, depending on what you are doing.

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