Linux man pages : exit (2)
_EXIT(2) Linux Programmer's Manual _EXIT(2)
_exit, _Exit - terminate the current process
void _exit(int status);
void _Exit(int status);
The function _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 par-
ent is sent a SIGCHLD signal.
The value status is returned to the parent process as the process's
exit status, and can be collected using one of the wait family of
The function _Exit is equivalent to _exit.
These functions do not return.
SVr4, SVID, POSIX, X/OPEN, BSD 4.3. The function _Exit() was intro-
duced by C99.
For a discussion on the effects of an exit, the transmission of exit
status, zombie processes, signals sent, etc., see exit(3).
The function _exit is like exit(), but does not call any functions reg-
istered with the ANSI C atexit function, nor any registered signal han-
dlers. Whether it flushes standard I/O buffers and removes temporary
files created with tmpfile(3) is implementation-dependent. On the
other hand, _exit does close open file descriptors, and this may cause
an unknown delay, waiting for pending output to finish. If the delay is
undesired, it may be useful to call functions like tcflush() before
calling _exit(). Whether any pending I/O is cancelled, and which pend-
ing I/O may be cancelled upon _exit(), is implementation-dependent.
fork(2), execve(2), waitpid(2), wait4(2), kill(2), wait(2), exit(3),
Linux 2001-11-17 _EXIT(2)