xref: /freebsd-13.1/lib/libc/sys/_exit.2 (revision 578d29dd)
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32.\"     @(#)_exit.2	8.1 (Berkeley) 6/4/93
33.\" $FreeBSD$
34.\"
35.Dd June 4, 1993
36.Dt EXIT 2
37.Os BSD 4
38.Sh NAME
39.Nm _exit
40.Nd terminate the calling process
41.Sh SYNOPSIS
42.Fd #include <unistd.h>
43.Ft void
44.Fn _exit "int status"
45.Sh DESCRIPTION
46The
47.Fn _exit
48function
49terminates a process with the following consequences:
50.Bl -bullet
51.It
52All of the descriptors open in the calling process are closed.
53This may entail delays, for example, waiting for output to drain;
54a process in this state may not be killed, as it is already dying.
55.It
56If the parent process of the calling process has an outstanding
57.Xr wait 2
58call
59or catches the
60.Dv SIGCHLD
61signal,
62it is notified of the calling process's termination and
63the
64.Em status
65is set as defined by
66.Xr wait 2 .
67.It
68The parent process-ID of all of the calling process's existing child
69processes are set to 1; the initialization process
70(see the
71.Sx DEFINITIONS
72section of
73.Xr intro 2 )
74inherits each of these processes.
75.It
76If the termination of the process causes any process group
77to become orphaned (usually because the parents of all members
78of the group have now exited; see
79.Dq orphaned process group
80in
81.Xr intro 2 ) ,
82and if any member of the orphaned group is stopped,
83the
84.Dv SIGHUP
85signal and the
86.Dv SIGCONT
87signal are sent to all members of the newly-orphaned process group.
88.It
89If the process is a controlling process (see
90.Xr intro 2 ) ,
91the
92.Dv SIGHUP
93signal is sent to the foreground process group of the controlling terminal,
94and all current access to the controlling terminal is revoked.
95.El
96.Pp
97Most C programs call the library routine
98.Xr exit 3 ,
99which flushes buffers, closes streams, unlinks temporary files, etc.,
100before
101calling
102.Fn _exit .
103.Sh RETURN VALUES
104.Fn _exit
105can never return.
106.Sh SEE ALSO
107.Xr fork 2 ,
108.Xr sigaction 2 ,
109.Xr wait 2 ,
110.Xr exit 3
111.Sh STANDARDS
112The
113.Fn _exit
114function call is expected to conform to
115.St -p1003.1-90 .
116.Sh HISTORY
117An
118.Fn _exit
119function call appeared in
120.At v7 .
121