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 dur-
       ing exit processing; the new registration 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 remain-
       ing 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 reg-
       istered.

       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  success-
       ful 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_NOCLD-
       WAIT, 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 foreground process group of this controlling terminal is sent a SIGHUP signal, and the terminal is  disas-
       sociated 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 3.25 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)