Why proper error handling should ALWAYS be done

[Tuna-Fish]

Yep.

But Wy, this likely has to do with the differences between the size of your swap file, and total RAM. You're probably running under a more constrained system, so you really are hitting the "low memory handling" of Linux whereas some of these other guys may have systems where their test cases don't trigger the behavior (so they assume it doesn't exist). I haven't looked at the algorithm Linux uses for figuring out how much it will over-commit. It may be that this is relative to how much swap space and RAM you have. I have not heard of a way of asking Linux what this amount would be. And even if you could, it still doesn't change the fact that malloc can return 0. (Can we please put this rumor to bed?)

There is no algorithm for that.
As I said in my post that had the code, it returns 0 if you ask for more than you have contiguous address space.

Linux will overcommit memory to infinity, but malloc returns 0 when (per process) address space runs out.