p_free_context_handler</span></a> free_context</code></em>,
                         <em class="parameter"><code><span class="type">void</span> *map_context</code></em>);</pre>
            <p>Add a librdf_iterator mapping function.</p>
            <p>Adds an iterator mapping function which operates over the iterator to
                select which elements are returned; it will be applied as soon as
                this method is called.</p>
            <p>Several mapping functions can be added and th