utime, utimes - change file last access and modification times
#include <utime.h>
int utime(const char *filename,
const struct utimbuf *_Nullable times);
#include <sys/time.h>
int utimes(const char *filename,
const struct timeval times[_Nullable 2]);
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. The status change time (ctime) will be set to the current
time, even if the other time stamps don't actually change.
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.
On success, zero is returned. On error, -1 is returned, and
errno
is set to indicate the error.