1 .\" Copyright (c) 1993 by Thomas Koenig (ig25@rz.uni-karlsruhe.de)
3 .\" Permission is granted to make and distribute verbatim copies of this
4 .\" manual provided the copyright notice and this permission notice are
5 .\" preserved on all copies.
7 .\" Permission is granted to copy and distribute modified versions of this
8 .\" manual under the conditions for verbatim copying, provided that the
9 .\" entire resulting derived work is distributed under the terms of a
10 .\" permission notice identical to this one.
12 .\" Since the Linux kernel and libraries are constantly changing, this
13 .\" manual page may be incorrect or out-of-date. The author(s) assume no
14 .\" responsibility for errors or omissions, or for damages resulting from
15 .\" the use of the information contained herein. The author(s) may not
16 .\" have taken the same level of care in the production of this manual,
17 .\" which is licensed free of charge, as they might when working
20 .\" Formatted or processed versions of this manual, if unaccompanied by
21 .\" the source, must acknowledge the copyright and authors of this work.
23 .\" Modified Wed Jul 21 22:35:42 1993 by Rik Faith (faith@cs.unc.edu)
24 .\" Modified 18 Mar 1996 by Martin Schulze (joey@infodrom.north.de):
25 .\" Corrected description of getwd().
26 .\" Modified Sat Aug 21 12:32:12 MET 1999 by aeb - applied fix by aj
27 .\" Modified Mon Dec 11 13:32:51 MET 2000 by aeb
28 .\" Modified Thu Apr 22 03:49:15 CEST 2002 by Roger Luethi <rl@hellgate.ch>
30 .TH GETCWD 3 2010-09-20 "GNU" "Linux Programmer's Manual"
32 getcwd, getwd, get_current_dir_name \- Get current working directory
35 .B #include <unistd.h>
37 .BI "char *getcwd(char *" buf ", size_t " size );
39 .BI "char *getwd(char *" buf );
41 .B "char *get_current_dir_name(void);"
45 Feature Test Macro Requirements for glibc (see
46 .BR feature_test_macros (7)):
49 .BR get_current_dir_name ():
62 (_XOPEN_SOURCE\ >=\ 500 ||
63 _XOPEN_SOURCE\ &&\ _XOPEN_SOURCE_EXTENDED) &&
64 !(_POSIX_C_SOURCE\ >=\ 200809L || _XOPEN_SOURCE\ >=\ 700)
68 _BSD_SOURCE || _XOPEN_SOURCE\ >=\ 500 ||
69 _XOPEN_SOURCE\ &&\ _XOPEN_SOURCE_EXTENDED
74 These functions return a null-terminated string containing an
75 absolute pathname that is the current working directory of
77 The pathname is returned as the function result and via the argument
83 function copies an absolute pathname of the current working directory
84 to the array pointed to by
89 If the length of the absolute pathname of the current working directory,
90 including the terminating null byte, exceeds
92 bytes, NULL is returned, and
96 an application should check for this error, and allocate a larger
99 As an extension to the POSIX.1-2001 standard, Linux (libc4, libc5, glibc)
101 allocates the buffer dynamically using
106 In this case, the allocated buffer has the length
112 is allocated as big as necessary.
117 .BR get_current_dir_name ()
120 an array big enough to hold the absolute pathname of
121 the current working directory.
125 is set, and its value is correct, then that value will be returned.
136 argument should be a pointer to an array at least
139 If the length of the absolute pathname of the current working directory,
140 including the terminating null byte, exceeds
142 bytes, NULL is returned, and
146 (Note that on some systems,
148 may not be a compile-time constant;
149 furthermore, its value may depend on the file system, see
151 For portability and security reasons, use of
155 On success, these functions return a pointer to a string containing
156 the pathname of the current working directory.
161 this is the same value as
164 On failure, these functions return NULL, and
166 is set to indicate the error.
167 The contents of the array pointed to by
169 are undefined on error.
173 Permission to read or search a component of the filename was denied.
177 points to a bad address.
184 is not a null pointer.
193 The size of the null-terminated absolute pathname string exceeds
198 The current working directory has been unlinked.
203 argument is less than the length of the absolute pathname of the
204 working directory, including the terminating null byte.
205 You need to allocate a bigger array and try again.
208 conforms to POSIX.1-2001.
209 Note however that POSIX.1-2001 leaves the behavior of
216 is present in POSIX.1-2001, but marked LEGACY.
217 POSIX.1-2008 removes the specification of
223 does not define any errors for
226 .BR get_current_dir_name ()
229 Under Linux, the function
231 is a system call (since 2.1.92).
232 On older systems it would query
234 If both system call and proc file system are missing, a
235 generic implementation is called.
236 Only in that case can
237 these calls fail under Linux with
240 These functions are often used to save the location of the current working
241 directory for the purpose of returning to it later.
243 directory (".") and calling
245 to return is usually a faster and more reliable alternative when sufficiently
246 many file descriptors are available, especially on platforms other than Linux.