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  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  & 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 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.

   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),  waitpid(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/.