UTIME(2)                   Linux Programmer's Manual                  UTIME(2)
       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 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 */

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

       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.

       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().

       utime(): SVr4, POSIX.1-2001.
       utimes(): 4.3BSD

       chattr(1), futimesat(2), stat(2), futimes(3)

Linux 2.6.8                       2004-10-10                          UTIME(2)