EXIT(3)			   Linux Programmer's Manual		       EXIT(3)



NAME
       exit - cause normal process termination

SYNOPSIS
       #include <stdlib.h>

       void exit(int status);

DESCRIPTION
       The  exit() function causes normal process termination and the value of
       status & 0377 is returned to the parent (see wait(2)).

       All functions registered with atexit(3) and on_exit(3) are  called,  in
       the  reverse  order  of their registration.  (It is possible for one of
       these functions to use atexit(3) or on_exit(3)  to  register  an	 addi-
       tional  function	 to be executed during exit processing; the new regis-
       tration is added to the front of the list of functions that  remain  to
       be  called.)  If one of these functions does not return (e.g., it calls
       _exit(2), or kills itself with a signal), then none  of	the  remaining
       functions is called, and further exit processing (in particular, flush-
       ing of stdio(3) streams) is abandoned.  If a function has  been	regis-
       tered  multiple	times using atexit(3) or on_exit(3), then it is called
       as many times as it was registered.

       All open stdio(3) streams are flushed and  closed.   Files  created  by
       tmpfile(3) are removed.

       The  C standard specifies two constants, EXIT_SUCCESS and EXIT_FAILURE,
       that may be passed to exit() to	indicate  successful  or  unsuccessful
       termination, respectively.

RETURN VALUE
       The exit() function does not return.

ATTRIBUTES
       For   an	  explanation	of   the  terms	 used  in  this	 section,  see
       attributes(7).

       +----------+---------------+---------------------+
       |Interface | Attribute	  | Value		|
       +----------+---------------+---------------------+
       |exit()	  | Thread safety | MT-Unsafe race:exit |
       +----------+---------------+---------------------+
       The exit() function uses a global variable that is not protected, so it
       is not thread-safe.

CONFORMING TO
       POSIX.1-2001, POSIX.1-2008, C89, C99, SVr4, 4.3BSD.

NOTES
       It  is  undefined what happens if one of the functions registered using
       atexit(3) and on_exit(3) calls either exit() or longjmp(3).  Note  that
       a  call	to execve(2) removes registrations created using atexit(3) and
       on_exit(3).

       The use of EXIT_SUCCESS and EXIT_FAILURE is slightly more portable  (to
       non-UNIX	 environments) than the use of 0 and some nonzero value like 1
       or -1.  In particular, VMS uses a different convention.

       BSD has attempted to standardize exit codes; see the file <sysexits.h>.

       After exit(), the  exit	status	must  be  transmitted  to  the	parent
       process.	  There	 are three cases.  If the parent has set SA_NOCLDWAIT,
       or has set the SIGCHLD handler to SIG_IGN, the status is discarded.  If
       the parent was waiting on the child, it is notified of the exit status.
       In both cases the exiting process dies immediately.  If the parent  has
       not  indicated that it is not interested in the exit status, but is not
       waiting, the exiting process turns into a "zombie"  process  (which  is
       nothing	but a container for the single byte representing the exit sta-
       tus) so that the parent can learn the exit status when it  later	 calls
       one of the wait(2) functions.

       If  the implementation supports the SIGCHLD signal, this signal is sent
       to the parent.  If the parent has set  SA_NOCLDWAIT,  it	 is  undefined
       whether a SIGCHLD signal is sent.

       If  the process is a session leader and its controlling terminal is the
       controlling terminal of the session, then each  process	in  the	 fore-
       ground process group of this controlling terminal is sent a SIGHUP sig-
       nal, and the terminal is disassociated from this session,  allowing  it
       to be acquired by a new controlling process.

       If  the	exit of the process causes a process group to become orphaned,
       and if any member of the newly orphaned process group is stopped,  then
       a  SIGHUP  signal  followed  by	a  SIGCONT signal will be sent to each
       process in this process group.  See setpgid(2) for  an  explanation  of
       orphaned process groups.

SEE ALSO
       _exit(2), setpgid(2), wait(2), atexit(3), on_exit(3), tmpfile(3)

COLOPHON
       This  page  is  part of release 4.10 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				  2015-08-08			       EXIT(3)