xref: /freebsd/lib/libc/stdlib/exit.3 (revision 52267f7411adcc76ede961420e08c0e42f42d415)
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32.\"     @(#)exit.3	8.1 (Berkeley) 6/4/93
33.\" $FreeBSD$
34.\"
35.Dd September 9, 2002
36.Dt EXIT 3
37.Os
38.Sh NAME
39.Nm exit , _Exit
40.Nd perform normal program termination
41.Sh LIBRARY
42.Lb libc
43.Sh SYNOPSIS
44.In stdlib.h
45.Ft void
46.Fn exit "int status"
47.Ft void
48.Fn _Exit "int status"
49.Sh DESCRIPTION
50The
51.Fn exit
52and
53.Fn _Exit
54functions terminate a process.
55.Pp
56Before termination,
57.Fn exit
58performs the following functions in the order listed:
59.Bl -enum -offset indent
60.It
61Call the functions registered with the
62.Xr atexit 3
63function, in the reverse order of their registration.
64.It
65Flush all open output streams.
66.It
67Close all open streams.
68.It
69Unlink all files created with the
70.Xr tmpfile 3
71function.
72.El
73.Pp
74The
75.Fn _Exit
76function terminates without calling the functions registered with the
77.Xr atexit 3
78function, and may or may not perform the other actions listed.
79Both functions make the low-order eight bits of the
80.Fa status
81argument available to a parent process which has called a
82.Xr wait 2 Ns -family
83function.
84.Pp
85The C Standard
86.Pq St -isoC-99
87defines the values
88.Li 0 ,
89.Dv EXIT_SUCCESS ,
90and
91.Dv EXIT_FAILURE
92as possible values of
93.Fa status .
94Cooperating processes may use other values;
95in a program which might be called by a mail transfer agent, the
96values described in
97.Xr sysexits 3
98may be used to provide more information to the parent process.
99.Pp
100Note that
101.Fn exit
102does nothing to prevent bottomless recursion should a function registered
103using
104.Xr atexit 3
105itself call
106.Fn exit .
107Such functions must call
108.Fn _Exit
109instead (although this has other effects as well which may not be desired).
110.Sh RETURN VALUES
111The
112.Fn exit
113and
114.Fn _Exit
115functions
116never return.
117.Sh SEE ALSO
118.Xr _exit 2 ,
119.Xr wait 2 ,
120.Xr atexit 3 ,
121.Xr intro 3 ,
122.Xr sysexits 3 ,
123.Xr tmpfile 3
124.Sh STANDARDS
125The
126.Fn exit
127and
128.Fn _Exit
129functions conform to
130.St -isoC-99 .
131