[mmap]
fp: posix/mm/mmap
include: sys/mman.h unistd.h
if: defined _POSIX_MAPPED_FILES
prep: void *p;
call: p = mmap(NULL, 4092, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
success_cond: p != MAP_FAILED
failure_cond: p == MAP_FAILED
errno_on_fail: ETXTBSY