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32 .\" @(#)getcwd.3 8.2 (Berkeley) 12/11/93
33 .\" $FreeBSD: src/lib/libc/gen/getcwd.3,v 1.15 2001/10/01 16:08:51 ru Exp $
34 .\"
35 .Dd November 24, 1997
36 .Dt GETCWD 3
37 .Os
38 .Sh NAME
39 .Nm getcwd ,
40 .Nm getwd
41 .Nd get working directory pathname
42 .Sh LIBRARY
43 .Lb libc
44 .Sh SYNOPSIS
45 .In unistd.h
46 .Ft char *
47 .Fn getcwd "char *buf" "size_t size"
48 .Ft char *
49 .Fn getwd "char *buf"
50 .Sh DESCRIPTION
51 The
52 .Fn getcwd
53 function copies the absolute pathname of the current working directory
54 into the memory referenced by
55 .Fa buf
56 and returns a pointer to
57 .Fa buf .
58 The
59 .Fa size
60 argument is the size, in bytes, of the array referenced by
61 .Fa buf .
62 .Pp
63 If
64 .Fa buf
65 is
66 .Dv NULL ,
67 space is allocated as necessary to store the pathname.
68 This space may later be
69 .Xr free 3 Ns 'd .
70 .Pp
71 The function
72 .Fn getwd
73 is a compatibility routine which calls
74 .Fn getcwd
75 with its
76 .Fa buf
77 argument and a size of
78 .Dv MAXPATHLEN
79 (as defined in the include
80 file
81 .Aq Pa sys/param.h ) .
82 Obviously,
83 .Fa buf
84 should be at least
85 .Dv MAXPATHLEN
86 bytes in length.
87 .Pp
88 These routines have traditionally been used by programs to save the
89 name of a working directory for the purpose of returning to it.
90 A much faster and less error-prone method of accomplishing this is to
91 open the current directory
92 .Pq Ql .\&
93 and use the
94 .Xr fchdir 2
95 function to return.
96 .Sh RETURN VALUES
97 Upon successful completion, a pointer to the pathname is returned.
98 Otherwise a
99 .Dv NULL
100 pointer is returned and the global variable
101 .Va errno
102 is set to indicate the error.
103 In addition,
104 .Fn getwd
105 copies the error message associated with
106 .Va errno
107 into the memory referenced by
108 .Fa buf .
109 .Sh ERRORS
110 The
111 .Fn getcwd
112 function
113 will fail if:
114 .Bl -tag -width Er
115 .It Bq Er EACCES
116 Read or search permission was denied for a component of the pathname.
117 .It Bq Er EINVAL
118 The
119 .Fa size
120 argument is zero.
121 .It Bq Er ENOENT
122 A component of the pathname no longer exists.
123 .It Bq Er ENOMEM
124 Insufficient memory is available.
125 .It Bq Er ERANGE
126 The
127 .Fa size
128 argument is greater than zero but smaller than the length of the pathname
129 plus 1.
130 .El
131 .Sh SEE ALSO
132 .Xr chdir 2 ,
133 .Xr fchdir 2 ,
134 .Xr malloc 3 ,
135 .Xr strerror 3
136 .Sh STANDARDS
137 The
138 .Fn getcwd
139 function
140 conforms to
141 .St -p1003.1-90 .
142 The ability to specify a
143 .Dv NULL
144 pointer and have
145 .Fn getcwd
146 allocate memory as necessary is an extension.
147 .Sh HISTORY
148 The
149 .Fn getwd
150 function appeared in
151 .Bx 4.0 .
152 .Sh BUGS
153 The
154 .Fn getwd
155 function
156 does not do sufficient error checking and is not able to return very
157 long, but valid, paths.
158 It is provided for compatibility.