xref: /freebsd/lib/libc/gen/dirname.3 (revision e965ede2b5a5e18a61ff622887de4da796f4b301)
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2.\" Copyright (c) 1997 Todd C. Miller <Todd.Miller@courtesan.com>
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27.\" $OpenBSD: dirname.3,v 1.9 2000/04/18 03:01:25 aaron Exp $
28.\" $FreeBSD$
29.\"
30.Dd October 12, 2006
31.Dt DIRNAME 3
32.Os
33.Sh NAME
34.Nm dirname
35.Nd extract the directory part of a pathname
36.Sh SYNOPSIS
37.In libgen.h
38.Ft char *
39.Fn dirname "const char *path"
40.Sh DESCRIPTION
41The
42.Fn dirname
43function
44is the converse of
45.Xr basename 3 ;
46it returns a pointer to the parent directory of the pathname pointed to by
47.Fa path .
48Any trailing
49.Sq \&/
50characters are not counted as part of the directory
51name.
52If
53.Fa path
54is a null pointer, the empty string, or contains no
55.Sq \&/
56characters,
57.Fn dirname
58returns a pointer to the string
59.Qq \&. ,
60signifying the current directory.
61.Sh IMPLEMENTATION NOTES
62The
63.Fn dirname
64function
65returns a pointer to internal storage space allocated on the first call
66that will be overwritten
67by subsequent calls.
68.Pp
69Other vendor implementations of
70.Fn dirname
71may modify the contents of the string passed to
72.Fn dirname ;
73this should be taken into account when writing code which calls this function
74if portability is desired.
75.Sh RETURN VALUES
76On successful completion,
77.Fn dirname
78returns a pointer to the parent directory of
79.Fa path .
80.Pp
81If
82.Fn dirname
83fails, a null pointer is returned and the global variable
84.Va errno
85is set to indicate the error.
86.Sh ERRORS
87The following error codes may be set in
88.Va errno :
89.Bl -tag -width Er
90.It Bq Er ENAMETOOLONG
91The path component to be returned was larger than
92.Dv MAXPATHLEN .
93.El
94.Sh SEE ALSO
95.Xr basename 1 ,
96.Xr dirname 1 ,
97.Xr basename 3
98.Sh STANDARDS
99The
100.Fn dirname
101function conforms to
102.St -xpg4.2 .
103.Sh HISTORY
104The
105.Fn dirname
106function first appeared in
107.Ox 2.2
108and
109.Fx 4.2 .
110.Sh AUTHORS
111.An "Todd C. Miller" Aq Todd.Miller@courtesan.com
112