+ <para>
+ This backend server handles both Z39.50 scan
+ and SRU scan. In order for a handler to distinguish between SRU (CQL) scan
+ Z39.50 Scan , it must check for a non-NULL value of
+ <literal>scanClause</literal>.
+ </para>
+ <note>
+ <para>
+ if designed today, it would be a choice using a union or similar,
+ but that would break binary compatibility with existing servers.
+ </para>
+ </note>