Merge from vendor branch BZIP:
[dragonfly.git] / lib / libc / gen / ctermid.3
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1.\" Copyright (c) 1990, 1991, 1993
2.\" The Regents of the University of California. All rights reserved.
3.\"
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5.\" modification, are permitted provided that the following conditions
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31.\"
32.\" @(#)ctermid.3 8.1 (Berkeley) 6/4/93
33.\" $FreeBSD: src/lib/libc/gen/ctermid.3,v 1.5.2.4 2003/03/15 15:11:05 trhodes Exp $
44cb301e 34.\" $DragonFly: src/lib/libc/gen/ctermid.3,v 1.3 2006/05/26 19:39:36 swildner Exp $
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35.\"
36.Dd June 4, 1993
37.Dt CTERMID 3
38.Os
39.Sh NAME
40.Nm ctermid
41.Nd generate terminal pathname
42.Sh LIBRARY
43.Lb libc
44.Sh SYNOPSIS
45.In stdio.h
46.Ft char *
47.Fn ctermid "char *buf"
48.Ft char *
49.Fn ctermid_r "char *buf"
50.Sh DESCRIPTION
51The
52.Fn ctermid
53function generates a string, that, when used as a pathname, refers to
54the current controlling terminal of the calling process.
55.Pp
56If
57.Fa buf
58is the
59.Dv NULL
60pointer, a pointer to a static area is returned.
61Otherwise, the pathname is copied into the memory referenced by
62.Fa buf .
63The argument
64.Fa buf
65is assumed to be at least
66.Dv L_ctermid
67(as defined in the include
68file
44cb301e 69.In stdio.h )
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70bytes long.
71.Pp
72The
73.Fn ctermid_r
74function
75provides the same functionality as
76.Fn ctermid
77except that if
78.Fa buf
79is a
80.Dv NULL
81pointer,
82.Dv NULL
83is returned.
84.Pp
85The current implementation simply returns
86.Ql /dev/tty .
87.Sh RETURN VALUES
88Upon successful completion, a
89.Pf non- Dv NULL
90pointer is returned.
91Otherwise, a
92.Dv NULL
93pointer is returned and the global variable
94.Va errno
95is set to indicate the error.
96.Sh ERRORS
97The current implementation detects no error conditions.
98.Sh SEE ALSO
99.Xr ttyname 3
100.Sh STANDARDS
101The
102.Fn ctermid
103function conforms to
104.St -p1003.1-88 .
105.Sh BUGS
106By default the
107.Fn ctermid
108function
109writes all information to an internal static object.
110Subsequent calls to
111.Fn ctermid
112will modify the same object.