NAME
utime, utimes - change access and/or modification times of an inode
SYNOPSIS
#include <sys/types.h>
#include <utime.h>
I int utime(const char * filename , const struct utimbuf * buf );
#include <sys/time.h>
I int utimes(const char * filename , const struct timeval times [2]);
DESCRIPTION
R utime ()
changes the access and modification times of the inode specified by
filename
to the
R actime and modtime
fields of
buf
respectively.
If
buf
is NULL, then the access and modification times of the file are set
to the current time.
Changing time stamps is permitted when: either
the process has appropriate privileges (Linux: has the
CAP_FOWNER
capability), or the effective user ID equals the user ID
of the file, or
buf
must is NULL and the process has write permission to the file.
The
utimbuf
structure is:
struct utimbuf {
time_t actime; /* access time */
time_t modtime; /* modification time */
};
The function
R utime ()
allows specification of time stamps with a resolution of 1 second.
The function
R utimes ()
is similar, but allows a resolution of 1 microsecond.
Here
R times [0]
refers to access time, and
R times [1]
to modification time.
The
timeval
structure is:
struct timeval {
long tv_sec; /* seconds */
long tv_usec; /* microseconds */
};
RETURN VALUE
On success, zero is returned.
On error, -1 is returned, and
errno
is set appropriately.
ERRORS
EACCES
Search permission is denied for one of the directories in
the path prefix of
path
(see also
path_resolution(7)),
or
buf
is NULL and the process does not have permission to change the time stamps
(see above).
ENOENT
filename
does not exist.
EPERM
buf
is not NULL and the process does not have permission to change the time stamps.
EROFS
path
resides on a read-only file system.
CONFORMING TO
R utime ():
SVr4, POSIX.1-2001.
R utimes ():
4.3BSD
NOTES
Linux does not allow changing the time stamps on an immutable file,
or setting the time stamps to something other than the current time
on an append-only file.
In libc4 and libc5,
R utimes ()
is just a wrapper for
R utime ()
and hence does not allow a subsecond resolution.
POSIX.1-2001 marks
R utimes ()
legacy, which is strange since it provides more functionality than
R utime ().
BUGS
Linux is not careful to distinguish between the
EACCES
and
EPERM
error returns.
On the other hand, POSIX.1-2001 is buggy in its error description for
R utimes ().
SEE ALSO
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