| NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | CONFORMING TO | NOTES | SEE ALSO | COLOPHON | The Linux Programming Interface |
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
additional function to be executed during 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 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.
The exit() function does not return.
SVr4, 4.3BSD, POSIX.1-2001, C89, C99.
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 on_exit(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
foreground 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.
_exit(2), setpgid(2), wait(2), atexit(3), on_exit(3), tmpfile(3)
This page is part of release 3.51 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 2013-02-14 EXIT(3)
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