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UTIMES(2)                   BSD System Calls Manual                  UTIMES(2)

NAME
     utimes, futimes, utimensat, futimens -- set file access and modification
     times

SYNOPSIS
     #include <&lt;sys/time.h>&gt;

     int
     utimes(const char *file, const struct timeval *times);

     int
     futimes(int fd, const struct timeval *times);

     #include <&lt;sys/stat.h>&gt;
     #include <&lt;fcntl.h>&gt;

     int
     utimensat(int fd, const char *file, const struct timespec times[2],
         int flag);

     int
     futimens(int fd, const struct timespec times[2]);

DESCRIPTION
     The access and modification times of the file named by path or referenced
     by fd are changed as specified by the argument times.

     If times is NULL, the access and modification times are set to the cur-
     rent time.  The caller must be the owner of the file, have permission to
     write the file, or be the superuser.

     If times is non-null, it is assumed to point to an array of two timeval
     structures.  The access time is set to the value of the first element,
     and the modification time is set to the value of the second element.  The
     caller must be the owner of the file or be the superuser.

     In either case, the inode-change-time of the file is set to the current
     time.

     The utimensat() and futimens() are equivalent to utimes() and futimes(),
     respectively, with the following differences.

     Both utimensat() and futimens() take two timespec values instead of two
     timeval values.  Further, either of the tv_nsec fields can be set to one
     of the following special values defined in <sys/stat.h>, in which case
     the value of tv_sec is ignored:

           UTIME_NOW   Set the respective timestamp to the greatest value sup-
                       ported that is not greater than the current time.
           UTIME_OMIT  Do not change the respective timestamp.

     Additionally, if the path argument to utimensat() specifies a relative
     path, the file whose timestamps are changed is determined relative to the
     directory associated with file descriptor fd instead of the current work-
     ing directory.

     If utimensat() is passed the special value AT_FDCWD (defined in
     <fcntl.h>) in the fd parameter, the current working directory is used.

     The flag argument is the bitwise OR of zero or more of the following val-
     ues:

           AT_SYMLINK_NOFOLLOW  If path names a symbolic link, then the time-
                                stamps of the symbolic link are changed.

RETURN VALUES
     Upon successful completion, the value 0 is returned; otherwise the
     value -1 is returned and the global variable errno is set to indicate the
     error.

ERRORS
     utimes() and utimensat() will fail if:

     [EACCES]           Search permission is denied for a component of the
                        path prefix; or the times argument is NULL and the
                        effective user ID of the process does not match the
                        owner of the file, and is not the superuser, and write
                        access is denied.

     [EFAULT]           file or times points outside the process's allocated
                        address space.

     [EIO]              An I/O error occurred while reading or writing the
                        affected inode.

     [ELOOP]            Too many symbolic links were encountered in translat-
                        ing the pathname.

     [ENAMETOOLONG]     A component of a pathname exceeded NAME_MAX charac-
                        ters, or an entire pathname (including the terminating
                        NUL) exceeded PATH_MAX bytes.

     [ENOENT]           The named file does not exist.

     [ENOTDIR]          A component of the path prefix is not a directory.

     [EPERM]            The times argument is not NULL and the calling
                        process's effective user ID does not match the owner
                        of the file and is not the superuser.

     [EROFS]            The file system containing the file is mounted read-
                        only.

     Additionally, utimensat() will fail if:

     [EINVAL]           The value of the flag argument was neither zero nor
                        AT_SYMLINK_NOFOLLOW.

     [EBADF]            The file argument specifies a relative path and the fd
                        argument is neither AT_FDCWD nor a valid file descrip-
                        tor.

     [ENOTDIR]          The file argument specifies a relative path and the fd
                        argument is a valid file descriptor but it does not
                        reference a directory.

     [EACCES]           The file argument specifies a relative path but search
                        permission is denied for the directory which the fd
                        file descriptor references.

     futimes() and futimens() will fail if:

     [EBADF]            fd does not refer to a valid descriptor.

     [EACCES]           The times argument is NULL and the effective user ID
                        of the process does not match the owner of the file,
                        and is not the superuser, and write access is denied.

     [EFAULT]           times points outside the process's allocated address
                        space.

     [EIO]              An I/O error occurred while reading or writing the
                        affected inode.

     [EPERM]            The times argument is not NULL and the calling
                        process's effective user ID does not match the owner
                        of the file and is not the superuser.

     [EROFS]            The file system containing the file is mounted read-
                        only.

SEE ALSO
     clock_gettime(2), stat(2), utime(3)

STANDARDS
     The utimes(), utimensat(), and futimens() functions conform to IEEE Std
     1003.1-2008 (``POSIX.1'').

HISTORY
     The predecessors of utimes() were smdate() in Version 1 AT&T UNIX,
     mdate() in Version 3 AT&T UNIX, and utime() in Version 7 AT&T UNIX; the
     latter first supported the concept of an access time in addition to the
     modification time.

     The utimes() function call appeared in 4.2BSD.  The futimes() function
     call appeared in NetBSD 1.2.  The utimensat() and futimens() function
     calls appeared in OpenBSD 5.0.

CAVEATS
     IEEE Std 1003.1-2008 (``POSIX.1'') specifies that utimensat() and
     futimens() shall mark the last file status change timestamp (i.e.
     st_ctim) for update upon successful completion.  However, currently some
     filesystems (e.g. UFS) will not do so if UTIME_OMIT is specified for the
     modification timestamp argument.

BSD                             April 28, 2017                             BSD