Index: ext/libicpf/src/cfg.h
===================================================================
diff -u -N -r0e69c2afbbe421971214a48e18c00f24a051518f -rc53cff389f468ccd962ceeea6c1f45da58a49258
--- ext/libicpf/src/cfg.h	(.../cfg.h)	(revision 0e69c2afbbe421971214a48e18c00f24a051518f)
+++ ext/libicpf/src/cfg.h	(.../cfg.h)	(revision c53cff389f468ccd962ceeea6c1f45da58a49258)
@@ -66,6 +66,8 @@
 
 extern config *__g_cfg;
 
+ICPFTEMPL_EXTERN template class LIBICPF_API callback2<ptr_t, ulong_t, ptr_t>;
+
 /** \brief Structure contain information about one property.
  *
  *  Struct is used to store information about any property type (name, value,