Index: sources/canbus/caninterface.h
===================================================================
diff -u -r7d23aecac8db9b7495e7d505f55bba5a0d510360 -r805119c460b4a266d6401c8705f4427e7fbe270f
--- sources/canbus/caninterface.h	(.../caninterface.h)	(revision 7d23aecac8db9b7495e7d505f55bba5a0d510360)
+++ sources/canbus/caninterface.h	(.../caninterface.h)	(revision 805119c460b4a266d6401c8705f4427e7fbe270f)
@@ -25,6 +25,7 @@
 
 // forward declarations
 class tst_canbus;
+class tst_acknow;
 
 // namespace
 namespace Can {
@@ -44,6 +45,7 @@
 
     // friends
     friend class ::tst_canbus;
+    friend class ::tst_acknow;
 
     // constants
     const char    *_canType             = "socketcan";