1EXIT(3) Linux Programmer's Manual EXIT(3)
2
6 exit - cause normal process termination
7
9 #include <stdlib.h>
10 void exit(int status);
12
14 The exit() function causes normal process termination and the value of
15 status & 0377 is returned to the parent (see wait(2)).
16 All functions registered with atexit() and on_exit() are called, in the
18 reverse order of their registration. (It is possible for one of these
19 functions to use atexit() or on_exit() to register an additional func‐
20 tion to be executed during exit processing; the new registration is
21 added to the front of the list of functions that remain to be called.)
22 All open streams are flushed and closed. Files created by tmpfile()
24 are removed.
25 The C standard specifies two constants, EXIT_SUCCESS and EXIT_FAILURE,
27 that may be passed to exit() to indicate successful or unsuccessful
28 termination, respectively.
29
31 The exit() function does not return.
32
34 SVr4, 4.3BSD, POSIX.1-2001, C89, C99.
35
37 It is undefined what happens if one of the functions registered using
38 atexit() and on_exit() calls either exit() or longjmp().
39 The use of EXIT_SUCCESS and EXIT_FAILURE is slightly more portable (to
41 non-Unix environments) than that of 0 and some non-zero value like 1 or
42 -1. In particular, VMS uses a different convention.
43 BSD has attempted to standardize exit codes; see the file <sysexits.h>.
45 After exit(), the exit status must be transmitted to the parent
47 process. There are three cases. If the parent has set SA_NOCLDWAIT, or
48 has set the SIGCHLD handler to SIG_IGN, the status is discarded. If the
49 parent was waiting on the child it is notified of the exit status. In
50 both cases the exiting process dies immediately. If the parent has not
51 indicated that it is not interested in the exit status, but is not
52 waiting, the exiting process turns into a "zombie" process (which is
53 nothing but a container for the single byte representing the exit sta‐
54 tus) so that the parent can learn the exit status when it later calls
55 one of the wait() functions.
56 If the implementation supports the SIGCHLD signal, this signal is sent
58 to the parent. If the parent has set SA_NOCLDWAIT, it is undefined
59 whether a SIGCHLD signal is sent.
60 If the process is a session leader and its controlling terminal is the
62 controlling terminal of the session, then each process in the fore‐
63 ground process group of this controlling terminal is sent a SIGHUP sig‐
64 nal, and the terminal is disassociated from this session, allowing it
65 to be acquired by a new controlling process.
66 If the exit of the process causes a process group to become orphaned,
68 and if any member of the newly orphaned process group is stopped, then
69 a SIGHUP signal followed by a SIGCONT signal will be sent to each
70 process in this process group.
71
73 _exit(2), wait(2), atexit(3), on_exit(3), tmpfile(3)
74 2001-11-17 EXIT(3)