_exit - terminate the current process
void _exit(int status);
_exit terminates the calling process immediately. Any open
file descriptors belonging to the process are closed; any
children of the process are inherited by process 1, init,
and the process's parent is sent a SIGCHLD signal.
status is returned to the parent process as the process's
exit status, and can be collected using one of the wait
family of calls.
_exit never returns.
SVr4, SVID, POSIX, X/OPEN, BSD 4.3
_exit does not call any functions registered with the ANSI
C atexit function and does not flush standard I/O buffers.
To do these things, use exit(3).
fork(2), execve(2), waitpid(2), wait4(2), kill(2),