_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(): _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 process's parent is sent a SIGCHLD sig-
       nal.

       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
       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), waitpid(2), atexit(3), exit(3), on_exit(3), termios(3)

COLOPHON
       This page is part of release 3.25 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)