utime, utimes — change access and/or modification times of an inode
#include <sys/types.h> #include <utime.h>
int
utime( |
const char * | filename, |
const struct utimbuf * | buf) ; |
#include <sys/time.h>
int
utimes( |
const char * | filename, |
const struct timeval | times[2]) ; |
utime
() changes the access
and modification times of the inode specified by filename
to the 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 utime
() allows
specification of time stamps with a resolution of 1 second.
The function utimes
() is
similar, but allows a resolution of 1 microsecond. Here
times
[0] refers to
access time, and times
[1] to modification
time.
The timeval
structure is:
struct timeval { long tv_sec
; /* seconds */long tv_usec
; /* microseconds */};
On success, zero is returned. On error, −1 is
returned, and errno
is set
appropriately.
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).
filename
does not exist.
buf
is not
NULL and the process does not have permission to change
the time stamps.
path
resides on a read-only file system.
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, utimes
()
is just a wrapper for utime
()
and hence does not allow a subsecond resolution.
POSIX.1-2001 marks utimes
()
legacy, which is strange since it provides more functionality
than utime
().
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
utimes
().
chattr(1), futimesat(2), stat(2), futimes(3)
Copyright (c) 1992 Drew Eckhardt (drew@cs.colorado.edu), March 28, 1992 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. Modified by Michael Haardt <michael@moria.de> Modified 1993-07-24 by Rik Faith <faith@cs.unc.edu> Modified 1995-06-10 by Andries Brouwer <aeb@cwi.nl> Modified 2004-06-23 by Michael Kerrisk <mtk-manpages@gmx.net> Modified 2004-10-10 by Andries Brouwer <aeb@cwi.nl> |