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

       exit - cause normal process termination

       #include <stdlib.h>

       void exit(int status);

       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.

       The exit() function does not return.

       For   an   explanation   of   the  terms  used  in  this  section,  see

       |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.

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

       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

       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.

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

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       description of the project, information about reporting bugs,  and  the
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Linux                             2015-08-08                           EXIT(3)
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