* call-seq:
 * conn.search_ext(base_dn, scope, filter, attrs=nil, attrsonly=false,
 *                 sctrls, cctrls, sec=0, usec=0, s_attr=nil, s_proc=nil)
 *                 { |entry| }  => self
 * Perform a search, with the base DN +base_dn+, a scope of +scope+ and a
 * search filter of +filter+.
 * If +attrs+ is present, it should be an array of the attributes that the
 * search should return. By default, all attributes are returned, which is the
 * same as specifying an empty array or *nil*. Alternatively, +attrs+ may be a
 * single string, in which case it will be treated as a single element array.
 * If +attrsonly+ is *true*, attributes will be returned, but not their values.
 * +sctrls+ is an array of server controls, whilst +cctrls+ is an array of
 * client controls.
 * If +sec+ and/or +usec+ are given, they define the time-out for the search in
 * seconds and microseconds, respectively.
 * If +s_attr+ is given, it specifies the attribute on which to sort the
 * entries returned by the server. If +s_proc+ is given, it specifies a Proc
 * object that will be used to sort the entries returned by the server.
 * Note that not all results may be returned by this method. If a
 * size limit has been set for the number of results to be returned and this
 * limit is exceeded, the results set will be truncated. You can check for
 * this by calling LDAP::Conn#err immediately after this method and comparing
rb_ldap_conn_search_ext_s (int argc, VALUE argv[], VALUE self)
  RB_LDAP_DATA *ldapdata;
  LDAPMessage *cmsg;
  LDAP *cldap;

  rb_ldap_conn_search_ext_i (argc, argv, self, &ldapdata, &cmsg);
  cldap = ldapdata->ldap;

  if (ldapdata->err == LDAP_SUCCESS
      || ldapdata->err == LDAP_SIZELIMIT_EXCEEDED)
      void *pass_data[] = { (void *) cldap, (void *) cmsg };
      rb_ensure (rb_ldap_conn_search_b, (VALUE) pass_data,
                 rb_ldap_msgfree, (VALUE) cmsg);

  return self;