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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | CONFORMING TO | NOTES | SEE ALSO | COLOPHON |
_EXIT(2) Linux Programmer's Manual _EXIT(2)
_exit, _Exit - terminate the calling process
#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
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 init(1) (or by the nearest
"subreaper" 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().
These functions do not return.
POSIX.1-2001, POSIX.1-2008, SVr4, 4.3BSD. The function _Exit() was
introduced by C99.
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 finish. 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 implementation-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.
execve(2), exit_group(2), fork(2), kill(2), wait(2), wait4(2),
waitpid(2), atexit(3), exit(3), on_exit(3), termios(3)
This page is part of release 4.12 of the Linux man-pages project. A
description of the project, information about reporting bugs, and the
latest version of this page, can be found at
https://www.kernel.org/doc/man-pages/.
Linux 2017-05-03 _EXIT(2)
Pages that refer to this page: clone(2), exit_group(2), fork(2), kill(2), prctl(2), ptrace(2), seccomp(2), setsid(2), shmop(2), syscalls(2), vfork(2), wait(2), atexit(3), daemon(3), exit(3), on_exit(3), pmgetconfig(3), system(3), systemd.service(5), persistent-keyring(7), signal-safety(7), socket(7), user-keyring(7), user-session-keyring(7)