exit

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



NAME
       exit - cause normal program termination

SYNOPSIS
       #include <stdlib.h>

       void exit(int status);

DESCRIPTION
       The  exit()  function  causes  normal  program termination and the 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, and all open streams are  flushed
       and closed.  Files created by tmpfile() are removed.

       The  C  standard	 specifies  two defines 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
       SVID 3, POSIX, BSD 4.3, ISO 9899 (‘‘ANSI C’’)

NOTES
       During  the  exit  processing,  it  is possible to register additional
       functions with atexit() and  on_exit().	 Always	 the  last-registered
       function	 is  removed  from  the	 chain	of  registered functions, and
       invoked.	 It is undefined  what	happens	 if  during  this  processing
       either exit() or longjmp() is called.

       The use of EXIT_SUCCESS and EXIT_FAILURE is slightly more portable (to
       non-Unix environments) than that 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 <sysex-
       its.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 the
       controlling terminal of the session, then each process  in  the	fore-
       ground  process	group  of  this controlling terminal is sent a SIGHUP
       signal, 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)