utime, utimes - change file last access and modification times

#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]);

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.

On success, zero is returned. On error, -1 is returned, and errno is set appropriately.

chattr(1), touch(1), futimesat(2), stat(2), utimensat(2), futimens(3), futimes(3), inode(7)