_EXIT(2) Linux Programmer's Manual _EXIT(2)NAME
_exit, _Exit - terminate the calling process
SYNOPSIS
#include <unistd.h>
void _exit(int status);
#include <stdlib.h>
void _Exit(int status);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
_Exit():
_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
DESCRIPTION
The function _exit() terminates the calling process "immediately". Any
open file descriptors belonging to the process are closed. Any chil‐
dren of the process are inherited by init(1) (or by the nearest "sub‐
reaper" process as defined through the use of the prctl(2)
PR_SET_CHILD_SUBREAPER operation). The process's parent is sent a
SIGCHLD signal.
The value status & 0377 is returned to the parent process as the
process's exit status, and can be collected using one of the wait(2)
family of calls.
The function _Exit() is equivalent to _exit().
RETURN VALUE
These functions do not return.
CONFORMING TO
POSIX.1-2001, POSIX.1-2008, SVr4, 4.3BSD. The function _Exit() was
introduced by C99.
NOTES
For a discussion on the effects of an exit, the transmission of exit
status, zombie processes, signals sent, and so on, see exit(3).
The function _exit() is like exit(3), but does not call any functions
registered with atexit(3) or on_exit(3). Open stdio(3) streams are not
flushed. On the other hand, _exit() does close open file descriptors,
and this may cause an unknown delay, waiting for pending output to fin‐
ish. If the delay is undesired, it may be useful to call functions
like tcflush(3) before calling _exit(). Whether any pending I/O is
canceled, and which pending I/O may be canceled upon _exit(), is imple‐
mentation-dependent.
C library/kernel differences
In glibc up to version 2.3, the _exit() wrapper function invoked the
kernel system call of the same name. Since glibc 2.3, the wrapper
function invokes exit_group(2), in order to terminate all of the
threads in a process.
SEE ALSOexecve(2), exit_group(2), fork(2), kill(2), wait(2), wait4(2), wait‐
pid(2), atexit(3), exit(3), on_exit(3), termios(3)COLOPHON
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latest version of this page, can be found at
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Linux 2017-05-03 _EXIT(2)