* call-seq:
 *  pl.insert_entry(pos, arg) -> result
 * Inserts an entry to the current playlist at position _pos_ in the playlist.
 * _arg_ can be either a URL or an id.
static VALUE
c_insert_entry (VALUE self, VALUE pos, VALUE arg)
        uint32_t id;
        int32_t ipos;


        ipos = check_int32 (pos);

        if (!NIL_P (rb_check_string_type (arg)))
                res = xmmsc_playlist_insert_url (xmms->real, pl->name,
                                                 ipos, StringValuePtr (arg));
        else {
                id = check_uint32 (arg);
                res = xmmsc_playlist_insert_id (xmms->real, pl->name,
                                                ipos, id);