Ubuntu manuals

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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 tv[2]);

DESCRIPTION

       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 tv[0] refers to access time, and
       tv[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 calls utimes() legacy.

BUGS

       Linux is not careful to distinguish between the EACCES and EPERM  error
       returns.   On  the  other hand, POSIX 1003.1-2003 is buggy in its error
       description for utimes().

CONFORMING TO

       utime(): SVr4, SVID, POSIX.  SVr4 documents additional error conditions
       EFAULT,   EINTR,  ELOOP,  EMULTIHOP,  ENAMETOOLONG,  ENOLINK,  ENOLINK,
       ENOTDIR.
       utimes(): 4.3BSD

SEE ALSO

       chattr(1), stat(2)