_exit

_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 & 0xFF 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 in-
       troduced 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 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 5.05 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                             2020-02-09                          _EXIT(2)