xref: /openbsd-src/lib/libc/gen/dirname.3 (revision b2ea75c1b17e1a9a339660e7ed45cd24946b230e)
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2.\" Copyright (c) 1997 Todd C. Miller <Todd.Miller@courtesan.com>
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27.\" $OpenBSD: dirname.3,v 1.11 2001/08/06 10:42:25 mpech Exp $
28.\"
29.Dd August 17, 1997
30.Dt DIRNAME 3
31.Os
32.Sh NAME
33.Nm dirname
34.Nd extract the directory portition of a pathname
35.Sh SYNOPSIS
36.Fd #include <libgen.h>
37.Ft char *
38.Fn dirname "const char *path"
39.Sh DESCRIPTION
40The
41.Fn dirname
42function is the converse of
43.Xr basename 3 ;
44it returns a pointer to the parent directory of the pathname pointed to by
45.Ar path .
46Any trailing
47.Sq \&/
48characters are not counted as part of the directory
49name.
50If
51.Ar path
52is a null pointer, the empty string, or contains no
53.Sq \&/
54characters,
55.Fn dirname
56returns a pointer to the string
57.Qq \&. ,
58signifying the current directory.
59.Sh RETURN VALUES
60On successful completion,
61.Fn dirname
62returns a pointer to the parent directory of
63.Ar path .
64.Pp
65If
66.Fn dirname
67fails, a null pointer is returned and the global variable
68.Va errno
69is set to indicate the error.
70.Sh ERRORS
71The following error codes may be set in
72.Va errno :
73.Bl -tag -width Er
74.It Bq Er ENAMETOOLONG
75The path component to be returned was larger than
76.Dv MAXPATHLEN .
77.El
78.Sh WARNINGS
79.Fn dirname
80returns a pointer to internal static storage space that will be overwritten
81by subsequent calls (each function has its own separate storage).
82.Pp
83Other vendor implementations of
84.Fn dirname
85may modify the contents of the string passed to
86.Fn dirname ;
87this should be taken into account when writing code which calls this function
88if portability is desired.
89.Sh SEE ALSO
90.Xr basename 1 ,
91.Xr dirname 1 ,
92.Xr basename 3
93.Sh STANDARDS
94The
95.Fn dirname
96function conforms to
97.St -xpg4.2 .
98.Sh HISTORY
99The
100.Fn dirname
101function first appeared in
102.Ox 2.2 .
103.Sh AUTHORS
104Todd C. Miller <Todd.Miller@courtesan.com>
105