http://bxr.su/OpenBSD/lib/libc/stdlib/malloc.c#omalloc ^Not the CVS repo, but close enough for those who want to check OpenBSD's malloc implementation. The malloc.conf manpage is also an interesting read : http://www.openbsd.org/cgi-bin/man.cgi/OpenBSD-current/man5/...

And some context around malloc and the various techniques OpenBSD implements to make exploitation of bugs more difficult: http://www.openbsd.org/papers/dev-sw-hostile-env.html

The tl;dr is : if your code compiles and runs on OpenBSD, chances are it will fine on other Unices. The opposite is not necessarily true though.

I don't think that source refutes the parent's point: only large allocations go directly to mmap/munmap as opposed to being cached. Of course, there are other anti-exploitation measures too...

Here's the CVS repo: http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/lib/libc/stdlib...

Well you could read the paper he just linked to.