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30 .\" @(#)utimes.2 8.1 (Berkeley) 6/4/93
31 .\"
32 .Dd August 17, 2011
33 .Dt UTIMES 2
34 .Os
35 .Sh NAME
36 .Nm utimes ,
37 .Nm lutimes ,
38 .Nm futimes ,
39 .Nm futimens ,
40 .Nm utimensat
41 .Nd set file access and modification times
42 .Sh LIBRARY
43 .Lb libc
44 .Sh SYNOPSIS
45 .In sys/time.h
46 .Ft int
47 .Fn utimes "const char *path" "const struct timeval times[2]"
48 .Ft int
49 .Fn lutimes "const char *path" "const struct timeval times[2]"
50 .Ft int
51 .Fn futimes "int fd" "const struct timeval times[2]"
52 .Ft int
53 .Fn futimens "int fd" "const struct timespec times[2]"
54 .Ft int
55 .Fn utimensat "int fd" "const char *path" "const struct timespec times[2]" "int flag"
56 .Sh DESCRIPTION
57 The access and modification times of the file named by
58 .Fa path
59 or referenced by
60 .Fa fd
61 are changed as specified by the argument
62 .Fa times .
63 .Pp
64 If
65 .Fa times
66 is
67 .Dv NULL ,
68 the access and modification times are set to the current time.
69 The caller must be the owner of the file, have permission to
70 write the file, or be the super-user.
71 .Pp
72 If
73 .Fa times
74 is
75 .Pf non- Dv NULL ,
76 it is assumed to point to an array of two timeval structures.
77 The access time is set to the value of the first element, and the
78 modification time is set to the value of the second element.
79 For file systems that support file birth (creation) times (such as
80 UFS2), the birth time will be set to the value of the second element
81 if the second element is older than the currently set birth time.
82 To set both a birth time and a modification time, two calls are
83 required; the first to set the birth time and the second to set
84 the (presumably newer) modification time.
85 Ideally a new system call will be added that allows the setting of
86 all three times at once.
87 The caller must be the owner of the file or be the super-user.
88 .Pp
89 In either case, the inode-change-time of the file is set to the current
90 time.
91 .Pp
92 .Fn lutimes
93 is like
94 .Fn utimes
95 except in the case where the named file is a symbolic link,
96 in which case
97 .Fn lutimes
98 changes the access and modification times of the link,
99 while
100 .Fn utimes
101 changes the times of the file the link references.
102 .Pp
103 .Fn futimens
104 is like
105 .Fn futimes
106 except that time is specified with nanosecond instead of microseconds.
107 .Pp
108 .Fn utimensat
109 also allows time to be specifed with nanoseconds.
110 When it operates on a symbolic link, it will change the target's time if
111 .Ar follow
112 is unset.
113 If
114 .Ar follow
115 is set to
116 .Dv AT_SYMLINK_NOFOLLOW ,
117 the symbolic link's dates are changed.
118 .Pp
119 The nanosecond fields for
120 .Fn futimens
121 and
122 .Fn utimensat
123 can be set to the special value
124 .Dv UTIME_NOW
125 to set the current time, or to
126 .Dv UTIME_OMIT
127 to let the time unchanged (this allows changing access time but not
128 modification time, and vice-versa).
129 .Pp
130 .Fn utimensat
131 is partially implemented.
132 It will return
133 .Er ENOSYS
134 for
135 .Fa fd
136 values different than
137 .Dv AT_FDCWD .
138 .Sh RETURN VALUES
139 Upon successful completion, a value of 0 is returned.
140 Otherwise, a value of \-1 is returned and
141 .Va errno
142 is set to indicate the error.
143 .Sh ERRORS
144 .Fn utimes ,
145 .Fn lutimes ,
146 and
147 .Fn utimensat
148 will fail if:
149 .Bl -tag -width Er
150 .It Bq Er EACCES
151 Search permission is denied for a component of the path prefix;
152 or the
153 .Fa times
154 argument is
155 .Dv NULL
156 and the effective user ID of the process does not
157 match the owner of the file, and is not the super-user, and write
158 access is denied.
159 .It Bq Er EFAULT
160 .Fa path
161 or
162 .Fa times
163 points outside the process's allocated address space.
164 .It Bq Er EIO
165 An I/O error occurred while reading or writing the affected inode.
166 .It Bq Er ELOOP
167 Too many symbolic links were encountered in translating the pathname.
168 .It Bq Er ENAMETOOLONG
169 A component of a pathname exceeded
170 .Brq Dv NAME_MAX
171 characters, or an entire path name exceeded
172 .Brq Dv PATH_MAX
173 characters.
174 .It Bq Er ENOENT
175 The named file does not exist.
176 .It Bq Er ENOTDIR
177 A component of the path prefix is not a directory.
178 .It Bq Er EPERM
179 The
180 .Fa times
181 argument is not
182 .Dv NULL
183 and the calling process's effective user ID
184 does not match the owner of the file and is not the super-user.
185 .It Bq Er EROFS
186 The file system containing the file is mounted read-only.
187 .El
188 .Pp
189 .Fn futimes
190 and
191 .Fn futimens
192 will fail if:
193 .Bl -tag -width Er
194 .It Bq Er EACCES
195 The
196 .Fa times
197 argument is
198 .Dv NULL
199 and the effective user ID of the process does not
200 match the owner of the file, and is not the super-user, and write
201 access is denied.
202 .It Bq Er EBADF
203 .Fa fd
204 does not refer to a valid descriptor.
205 .It Bq Er EFAULT
206 .Fa times
207 points outside the process's allocated address space.
208 .It Bq Er EIO
209 An I/O error occurred while reading or writing the affected inode.
210 .It Bq Er EPERM
211 The
212 .Fa times
213 argument is not
214 .Dv NULL
215 and the calling process's effective user ID
216 does not match the owner of the file and is not the super-user.
217 .It Bq Er EROFS
218 The file system containing the file is mounted read-only.
219 .El
220 .Sh SEE ALSO
221 .Xr stat 2 ,
222 .Xr utime 3 ,
223 .Xr symlink 7
224 .Sh STANDARDS
225 The
226 .Fn utimes
227 function conforms to
228 .St -p1003.1-2001 .
229 It was however marked as legacy in the
230 .St -p1003.1-2004
231 revision.
232 .Fn futimens
233 and
234 .Fn utimensat
235 functions conform to
236 .St -p1003.1-2008 .
237 .Sh HISTORY
238 The
239 .Fn utimes
240 function call appeared in
241 .Bx 4.2 .
242 The
243 .Fn futimes
244 function call appeared in
245 .Nx 1.2 .
246 The
247 .Fn lutimes
248 function call appeared in
249 .Nx 1.3 .
250 Birthtime setting support was added in
251 .Nx 5.0 .
252 .Fn futimens
253 and
254 .Fn utimensat
255 functions calls appreared in
256 .Nx 6.0 .
257 .Sh BUGS
258 .Fn utimensat
259 is partially implemented.