UTIME(2) Linux Programmer's Manual UTIME(2)NAME
utime, utimes - change access and/or modification times of an inode
SYNOPSIS
#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]);
DESCRIPTIONutime() changes the access and modification times of the inode speci‐
fied 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 appro‐
priate privileges (Linux: has the CAP_FOWNER capability), or the effec‐
tive 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 resolu‐
tion of 1 second. The function utimes() is similar, but allows a reso‐
lution 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 */
};
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(2)), 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.
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, 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().
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 utimes().
CONFORMING TOutime(): SVr4, POSIX.1-2001.
utimes(): 4.3BSD
SEE ALSOchattr(1), futimesat(2), stat(2), futimes(3)Linux 2.6.8 2004-10-10 UTIME(2)
