Libc (or the various other libs that compose libc) are not necessarily system calls, often they are wrappings of severals.
I'm talking about the `dlfnc.h` interfaces.
Are you saying that when you call dlsym(3) on OS X you get back a non-null pointer to memory that is not mapped inside your address space? That can't be, right? So where does your "weird" pointer actually come from and how is it connected to the allocation of huge blocks?
Seconded. Please post a test case that shows this failure.