[aidenn0]

brk() is undefined behavior if mmap is ever called.

[aidenn0]

I was wrong, it's only if you use MAP_FIXED to map an overlapping area.

[megous]

How so? Both syscalls are invoked pretty frequently together in the same program.

[chrisseaton]

Wow that's news to me - can you point me at the documentation for that?

[emilfihlman]

Can you post a definite source supporting this?

[luke0016]

There isn't one, because it's wrong.

Source: run strace on almost any useful Linux command (e.g. ls, sort, which, ...), you'll see it makes calls to both brk() and mmap().

[toast0]

The OP admitted it was wrong, but just because everyone does it doesn't mean it's not undefined behavior.