utime(2) — Linux manual pages

Linux manual pages	Section 2

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

	Note
	modern applications may prefer to use the interfaces described in utimensat(2).

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 filesystem.

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.

COLOPHON

This page is part of release 4.07 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at https://www.kernel.org/doc/man−pages/.

  Copyright (c) 1992 Drew Eckhardt (drewcs.colorado.edu), March 28, 1992

%%%LICENSE_START(VERBATIM)
Permission is granted to make and distribute verbatim copies of this
manual provided the copyright notice and this permission notice are
preserved on all copies.

Permission is granted to copy and distribute modified versions of this
manual under the conditions for verbatim copying, provided that the
entire resulting derived work is distributed under the terms of a
permission notice identical to this one.

Since the Linux kernel and libraries are constantly changing, this
manual page may be incorrect or out-of-date.  The author(s) assume no
responsibility for errors or omissions, or for damages resulting from
the use of the information contained herein.  The author(s) may not
have taken the same level of care in the production of this manual,
which is licensed free of charge, as they might when working
professionally.

Formatted or processed versions of this manual, if unaccompanied by
the source, must acknowledge the copyright and authors of this work.
%%%LICENSE_END

Modified by Michael Haardt <michaelmoria.de>
Modified 1993-07-24 by Rik Faith <faithcs.unc.edu>
Modified 1995-06-10 by Andries Brouwer <aebcwi.nl>
Modified 2004-06-23 by Michael Kerrisk <mtk.manpagesgmail.com>
Modified 2004-10-10 by Andries Brouwer <aebcwi.nl>

struct	utimbuf {
	time_t	`actime`;	/* access time */
	time_t	`modtime`;	/* modification time */
};

struct	timeval {
	long	`tv_sec`;	/* seconds */
	long	`tv_usec`;	/* microseconds */
};