Because I don't have a system library that provides a different malloc. It's a property of my API that malloc returns NULL and I don't have any control over tha

Because I don't have a system library that provides a different malloc. It's a property of my API that malloc returns NULL and I don't have any control over that. What I do have control over is what I do with data I get out of malloc. I have to check, somehow, for abnormal conditions. That is a requirement for using the malloc API. I get that this makes it hard to debug in some cases, so I might avoid that by religiously checking for NULL return from malloc and crashing immediately with a sensible error message. In the cases where getting a NULL return is not an error, like if I wrote a program to use as much heap as it can, I would ignore the NULL and proceed with the resources I can actually get.