NAME
utime, utimes - change file last access and modification times
SYNOPSIS
#include <sys/types.h>
#include <utime.h>
int utime(const char *filename, const struct utimbuf *times);
#include <sys/time.h>
int utimes(const char *filename, const struct timeval times[2]);
DESCRIPTION
The utime() system call changes the access and modification times of
the inode specified by filename to the actime and modtime fields of
times respectively.
If times is NULL, then the access and modification times of the file
are set to the current time.
Changing timestamps is permitted when: either the process has
appropriate privileges, or the effective user ID equals the user ID of
the file, or times is NULL and the process has write permission for the
file.
The utimbuf structure is:
struct utimbuf {
time_t actime; /* access time */
time_t modtime; /* modification time */
};
The utime() system call allows specification of timestamps with a
resolution of 1 second.
The utimes() system call is similar, but the times argument refers to
an array rather than a structure. The elements of this array are
timeval structures, which allow a precision of 1 microsecond for
specifying timestamps. The timeval structure is:
struct timeval {
long tv_sec; /* seconds */
long tv_usec; /* microseconds */
};
times[0] specifies the new access time, and times[1] specifies the new
modification time. If times is NULL, then analogously to utime(), the
access and modification times of the file are set to the current time.
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)).
EACCES times is NULL, the caller’s effective user ID does not match the
owner of the file, the caller does not have write access to the
file, and the caller is not privileged (Linux: does not have
either the CAP_DAC_OVERRIDE or the CAP_FOWNER capability).
ENOENT filename does not exist.
EPERM times is not NULL, the caller’s effective UID does not match the
owner of the file, and the caller is not privileged (Linux: does
not have the CAP_FOWNER capability).
EROFS path resides on a read-only file system.
CONFORMING TO
utime(): SVr4, POSIX.1-2001. POSIX.1-2008 marks utime() as obsolete.
utimes(): 4.3BSD, POSIX.1-2001.
NOTES
Linux does not allow changing the timestamps on an immutable file, or
setting the timestamps to something other than the current time on an
append-only file.
In libc4 and libc5, utimes() is just a wrapper for utime() and hence
does not allow a subsecond resolution.
SEE ALSO
chattr(1), futimesat(2), stat(2), utimensat(2), futimes(3), futimens(3)
COLOPHON
This page is part of release 3.24 of the Linux man-pages project. A
description of the project, and information about reporting bugs, can
be found at http://www.kernel.org/doc/man-pages/.