_EXIT(2) Linux Programmer s Manual _EXIT(2)
NAME _exit, _Exit - terminate the calling process
SYNOPSIS #include <unistd.h>
void _exit(int status);
void _Exit(int status);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
_Exit(): _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE; 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 processs par- ent is sent a SIGCHLD signal.
The value status is returned to the parent process as the processs 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 SVr4, POSIX.1-2001, 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, etc., see exit(3).
The function _exit() is like exit(3), but does not call any functions registered with atexit(3) or on_exit(3). 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(3) before calling _exit(). Whether any pending I/O is canceled, and which pending I/O may be canceled upon _exit(), is implementation-dependent.
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 ALSO execve(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 This page is part of release 3.22 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.
Linux 2008-11-27 _EXIT(2)