.
    There is a mechanism to extend the set of tags the library handles
    without modifying the library itself;
    this is described <a href="addingtags.html">elsewhere</a>.
  </p>
  <p>
    <tt>libtiff</tt> provides two interfaces for getting and setting tag
    values: <tt>TIFFGetField</tt> and <tt>TIFFSetField</tt>.
    These routines use a variable argument list-style interface to pass
    parameters of different type through a single function interface.
    The <i>get interface</i> takes one or mor