NAME
utimes,
lutimes,
futimes,
utimens,
lutimens,
futimens,
utimensat —
set file access and modification times
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <sys/time.h>
int
utimes(
const char
*path,
const struct timeval
times[2]);
int
lutimes(
const
char *path,
const struct
timeval times[2]);
int
futimes(
int
fd,
const struct timeval
times[2]);
#include <sys/stat.h>
int
utimens(
const
char *path,
const struct
timespec times[2]);
int
lutimens(
const
char *path,
const struct
timespec times[2]);
int
futimens(
int
fd,
const struct timespec
times[2]);
#include <sys/stat.h>
#include <fcntl.h>
int
utimensat(
int
fd,
const char *path,
const struct timespec
times[2],
int flag);
DESCRIPTION
The access and modification times of the file named by
path or referenced by
fd are
changed as specified by the argument
times.
If
times is
NULL
, the access and
modification times are set to the current time. The caller must be the owner
of the file, have permission to write the file, or be the super-user.
If
times is non-
NULL
, it is
assumed to point to an array of two timeval structures. The access time is set
to the value of the first element, and the modification time is set to the
value of the second element. For file systems that support file birth
(creation) times (such as UFS2), the birth time will be set to the value of
the second element if the second element is older than the currently set birth
time. To set both a birth time and a modification time, two calls are
required; the first to set the birth time and the second to set the
(presumably newer) modification time. Ideally a new system call will be added
that allows the setting of all three times at once. The caller must be the
owner of the file or be the super-user.
In either case, the inode-change-time of the file is set to the current time.
lutimes() is like
utimes() except in the
case where the named file is a symbolic link, in which case
lutimes() changes the access and modification times of the
link, while
utimes() changes the times of the file the link
references.
utimens(),
lutimens(), and
futimens() are like
utimes(),
lutimes(), and
futimes() respectively
except that time is specified with nanosecond instead of microsecond
precision.
utimensat() works the same way as
utimens()
except if
path is relative. In that case, it is looked
up from a directory whose file descriptor was passed as
fd. Search permission is required on this directory.
fd can be set to
AT_FDCWD
in
order to specify the current directory.
When it operates on a symbolic link,
utimensat() will change
the target's time unless
AT_SYMLINK_NOFOLLOW
is set in
flag. In that later case, the symbolic link's dates are
changed.
The nanosecond fields for
utimens(),
lutimens(),
futimens(), and
utimensat() can be set to the special value
UTIME_NOW
to set the current time, or to
UTIME_OMIT
to let the time unchanged (this allows
changing access time but not modification time, and vice-versa).
RETURN VALUES
The
utimes(),
lutimes(),
futimes(),
utimens(),
lutimens(),
futimens(), and
utimensat() functions return the value 0 if successful;
otherwise the value -1 is returned and the global variable
errno is set to indicate the error.
ERRORS
utimes(),
lutimes(),
utimens(),
lutimens(), and
utimensat() will fail if:
-
-
- [
EACCES
]
- Search permission is denied for a component of the path
prefix; or the times argument is
NULL
and the effective user ID of the process does
not match the owner of the file, and is not the super-user, and write
access is denied.
-
-
- [
EFAULT
]
- path or times
points outside the process's allocated address space.
-
-
- [
EIO
]
- An I/O error occurred while reading or writing the affected
inode.
-
-
- [
ELOOP
]
- Too many symbolic links were encountered in translating the
pathname.
-
-
- [
ENAMETOOLONG
]
- A component of a pathname exceeded
{
NAME_MAX
} characters, or an entire path name
exceeded {PATH_MAX
} characters.
-
-
- [
ENOENT
]
- The named file does not exist.
-
-
- [
ENOTDIR
]
- A component of the path prefix is not a directory.
-
-
- [
EPERM
]
- The times argument is not
NULL
and the calling process's effective user ID
does not match the owner of the file and is not the super-user.
-
-
- [
EROFS
]
- The file system containing the file is mounted
read-only.
In addition,
utimensat() will fail if:
-
-
- [
EBADF
]
- path does not specify an absolute
path and fd is neither
AT_FDCWD
nor a valid file descriptor open for
reading or searching.
-
-
- [
ENOTDIR
]
- path is not an absolute path and
fd is a file descriptor associated with a
non-directory file.
futimes() and
futimens() will fail if:
-
-
- [
EACCES
]
- The times argument is
NULL
and the effective user ID of the process does
not match the owner of the file, and is not the super-user, and write
access is denied.
-
-
- [
EBADF
]
- fd does not refer to a valid
descriptor.
-
-
- [
EFAULT
]
- times points outside the process's
allocated address space.
-
-
- [
EIO
]
- An I/O error occurred while reading or writing the affected
inode.
-
-
- [
EPERM
]
- The times argument is not
NULL
and the calling process's effective user ID
does not match the owner of the file and is not the super-user.
-
-
- [
EROFS
]
- The file system containing the file is mounted
read-only.
SEE ALSO
stat(2),
utime(3),
symlink(7)
STANDARDS
The
utimes() function conforms to
IEEE Std
1003.1-2001 (“POSIX.1”). It was however marked as legacy in
the
IEEE Std 1003.1-2004 (“POSIX.1”)
revision.
futimens() and
utimensat()
functions conform to
IEEE Std 1003.1-2008
(“POSIX.1”).
HISTORY
The
utimes() function call appeared in
4.2BSD. The
futimes() function call
appeared in
NetBSD 1.2. The
lutimes() function call appeared in
NetBSD
1.3. Birthtime setting support was added in
NetBSD
5.0.
futimens() and
utimensat()
functions calls appeared in
NetBSD 6.0.