_exit (2)
Leading comments
This manpage is Copyright (C) 1992 Drew Eckhardt;
and Copyright (C) 1993 Michael Haardt, Ian Jackson.
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NAME
_exit, _Exit - terminate the calling processSYNOPSIS
#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():
-
_XOPEN_SOURCE >= 600 || _ISOC99_SOURCE ||
_POSIX_C_SOURCE >= 200112L;
or cc -std=c99
DESCRIPTION
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 parent 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(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 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.