xref: /freebsd/lib/libc/gen/dirname.3 (revision fa9896e082a1046ff4fbc75fcba4d18d1f2efc19)
1.\" $OpenBSD: dirname.3,v 1.17 2007/05/31 19:19:28 jmc Exp $
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3.\" Copyright (c) 1997 Todd C. Miller <Todd.Miller@courtesan.com>
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17.Dd September 5, 2016
18.Dt DIRNAME 3
19.Os
20.Sh NAME
21.Nm dirname
22.Nd extract the directory part of a pathname
23.Sh SYNOPSIS
24.In libgen.h
25.Ft char *
26.Fn dirname "char *path"
27.Sh DESCRIPTION
28The
29.Fn dirname
30function is the converse of
31.Xr basename 3 ;
32it returns a pointer to the parent directory of the pathname pointed to by
33.Fa path .
34Any trailing
35.Sq \&/
36characters are not counted as part of the directory
37name.
38.Sh IMPLEMENTATION NOTES
39This implementation of
40.Fn dirname
41uses the buffer provided by the caller to store the resulting parent
42directory.
43Other vendor implementations may return a pointer to internal storage
44space instead.
45The advantage of the former approach is that it ensures thread-safety,
46while also placing no upper limit on the supported length of the
47pathname.
48.Sh RETURN VALUES
49If
50.Fa path
51is a null pointer, the empty string, or contains no
52.Sq \&/
53characters,
54.Fn dirname
55returns a pointer to the string
56.Qq \&. ,
57signifying the current directory.
58Otherwise,
59it returns a pointer to the parent directory of
60.Fa path .
61.Sh SEE ALSO
62.Xr basename 1 ,
63.Xr dirname 1 ,
64.Xr basename 3
65.Sh STANDARDS
66The
67.Fn dirname
68function conforms to
69.St -xpg4.2 .
70.Sh HISTORY
71The
72.Fn dirname
73function first appeared in
74.Ox 2.2
75and
76.Fx 4.2 .
77.Pp
78In
79.Fx 12.0 ,
80this function was reimplemented to store its result in the provided
81input buffer.
82.Sh AUTHORS
83.An Nuxi, the Netherlands
84