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 additional function to be executed during exit processing; the new  registra-
       tion  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,
       flushing  of  stdio(3)  streams)  is abandoned.	If a function has been registered 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.

CONFORMING TO

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

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).

       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
       status) 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 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 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 3.44 of the Linux man-pages project.  A description of the project, and information about reporting bugs, can
       be found at http://www.kernel.org/doc/man-pages/.

Linux								    2009-09-20								   EXIT(3)