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() and on_exit() are called, in the
       reverse  order of their registration.  (It is possible for one of these
       functions to use atexit() or on_exit() to register an additional  func-
       tion  to  be  executed  during exit processing; the new registration is
       added to the front of the list of functions that remain to be  called.)

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

CONFORMING TO
       SVr4, 4.3BSD, POSIX.1-2001.

NOTES
       It is undefined what happens if one of the functions  registered  using
       atexit() and on_exit() calls either exit() or longjmp().

       The  use of EXIT_SUCCESS and EXIT_FAILURE is slightly more portable (to
       non-Unix environments) than that of 0 and some non-zero 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  pro-
       cess. 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() 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 pro-
       cess in this process group.

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

                                  2001-11-17                           EXIT(3)