Understanding Memory Management, Part 1: C

Avoid as much as you can the C standard lib allocator, go directly to mmap system call with your own allocator if you know you won't use CPU without a MMU.

If you write a library, let the user code install its own allocator.

Sure, if one doesn't care about portable code.

What modern OS doesn't have the equivalent of mmap? Just som #ifdefs. I didn't know I'd ever hear "use malloc, because it's portable".

sylware is pretty much right anyway. Try to avoid malloc, or write smaller allocators on top of malloc.

Why bother with some #ifdefs when the ISO C standard library already does the job?

Because you're probably writing a much larger program so some ifdefs aren't a big deal :-).

This is a silly argument because at the end of the day, once you make your code portable, you've now duplicated 99% of malloc and free, and you've left a mess for the team or next guy to maintain on top of everything else. You've successfully lowered the abstraction floor which is already pretty low in C.