Perl Bug 7 - seek doesn't work in an >> append

I open a file to append, then try to seek() to the beginning of the file:

open(FILE,">>some_file") || die("Fie!\n");
print "Position: ",tell(FILE),"\n";
print "Position: ",tell(FILE),"\n";
print FILE "Should be on the first line\n";

The seek() doesn't do anything, though the tell() claims that it did.
(Run this a few times and look at "some_file" and watch the tell() values)

UPDATE:  Evidently this isn't a bug, the print ignores the location
and prints to the bottom of the file.  According to MJD:

  On your Linux system, opening a file in append mode means that the
  system automatically seeks the pointer to the end immediately prior to
  each write.  See the man page for open(2) for details:

               The  file  is  opened  in append mode. Before each
               write, the file pointer is positioned at  the  end
               of  the file, as if with lseek. ...