Index: doc/src/sgml/libpq.sgml
===================================================================
RCS file: /projects/cvsroot/pgsql/doc/src/sgml/libpq.sgml,v
retrieving revision 1.269
diff -C6 -r1.269 libpq.sgml
*** doc/src/sgml/libpq.sgml	13 Nov 2008 09:45:24 -0000	1.269
--- doc/src/sgml/libpq.sgml	14 Nov 2008 12:08:07 -0000
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*** 5252,5263 ****
--- 5252,5275 ----
  
        <para>
         A particular event procedure can be registered only once in any
         <structname>PGconn</>.  This is because the address of the procedure
         is used as a lookup key to identify the associated instance data.
        </para>
+ 
+       <note>
+        <para>
+         On windows, functions can have two different addresses: one accessed
+         from outside a DLL, obtained from the import library, and another from
+         inside a DLL.  For this reason, implementors should never directly expose
+         an event procedure.  If the event procedure is needed by an API user,
+         then its address should be returned by a library function; ie.
+         <literal>PGEventProc MyGetEventProc(void);</literal>.  This ensures that
+         the application and DLL are always using the same address.
+        </para>
+       </note>
       </listitem>
      </varlistentry>
     </variablelist>
    </sect2>
  
    <sect2 id="libpq-events-funcs">