diff --git a/Makefile.am b/Makefile.am
index 72d0dcb43..fbaecd794 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -25,10 +25,18 @@ BUILT_SOURCES =
 EXTRA_DIST =
 SUBDIRS =
 
+# Only use subdirs if really needed, prefer the include scheme below
 #SUBDIRS +=
 
+# core
 include $(top_srcdir)/src/lib/Makefile.am
 
+# plugins
+#include $(top_srcdir)/src...
+
+# tests
+include $(top_srcdir)/tests/examples/Makefile.am
+
 #EXTRA_DIST += admin debian doc depcomp README.BUILD LICENSE \
 #	cinelerra-cvs-current.spec
 AUTOMAKE_OPTIONS=foreign
diff --git a/src/lib/plugin.c b/src/lib/plugin.c
index 92149ad51..ec7b3f0a6 100644
--- a/src/lib/plugin.c
+++ b/src/lib/plugin.c
@@ -44,7 +44,7 @@ NOBUG_DEFINE_FLAG (cinelerra_plugin);
 /* errors */
 const char* CINELERRA_PLUGIN_SUCCESS = NULL;
 const char* CINELERRA_PLUGIN_EDLOPEN = "Could not open plugin";
-const char* CINELERRA_PLUGIN_EDHOOK = "Hook function failed";
+const char* CINELERRA_PLUGIN_EHOOK = "Hook function failed";
 const char* CINELERRA_PLUGIN_ENFOUND = "No such plugin";
 const char* CINELERRA_PLUGIN_ENIFACE = "No such interface";
 const char* CINELERRA_PLUGIN_EREVISION = "Interface revision too old";
@@ -304,11 +304,13 @@ cinelerra_interface_open (const char* name, const char* interface, size_t min_re
 }
 
 void
-cinelerra_interface_close (struct cinelerra_interface* self)
+cinelerra_interface_close (void* ptr)
 {
-  if(!self)
+  if(!ptr)
     return;
 
+  struct cinelerra_interface* self = (struct cinelerra_interface*) ptr;
+
   pthread_mutex_lock (&cinelerra_plugin_mutex);
 
   struct cinelerra_plugin* plugin = self->plugin;
diff --git a/src/lib/plugin.h b/src/lib/plugin.h
index 605da329c..74ab964b3 100644
--- a/src/lib/plugin.h
+++ b/src/lib/plugin.h
@@ -109,7 +109,7 @@ cinelerra_interface_open (const char* plugin, const char* name, size_t min_revis
  * @param self interface to be closed
  */
 void
-cinelerra_interface_close (struct cinelerra_interface* self);
+cinelerra_interface_close (void* self);
 
 /**
  * Tries to unload a plugin.
diff --git a/tests/examples/Makefile.am b/tests/examples/Makefile.am
new file mode 100644
index 000000000..c3ee8e033
--- /dev/null
+++ b/tests/examples/Makefile.am
@@ -0,0 +1,26 @@
+#  Copyright (C)         CinelerraCV
+#    2007,               Christian Thaeter <ct@pipapo.org>
+#
+#  This program is free software; you can redistribute it and/or
+#  modify it under the terms of the GNU General Public License as
+#  published by the Free Software Foundation; either version 2 of the
+#  License, or (at your option) any later version.
+#
+#  This program is distributed in the hope that it will be useful,
+#  but WITHOUT ANY WARRANTY; without even the implied warranty of
+#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#  GNU General Public License for more details.
+#
+#  You should have received a copy of the GNU General Public License
+#  along with this program; if not, write to the Free Software
+#  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+examples_srcdir = $(top_srcdir)/tests/examples
+noinst_PROGRAMS += plugin_example
+
+plugin_example_CFLAGS = $(CFLAGS) -std=gnu99 -Wall -Werror
+plugin_example_CPPFLAGS = $(CPPFLAGS) -std=gnu99 -Wall -Werror -I$(top_srcdir)/src/lib/
+plugin_example_LDADD = -lnobugmt -lpthread -ldl $(builddir)/libcin3.a
+
+plugin_example_SOURCES = $(examples_srcdir)/plugin_main.c
+noinst_HEADERS += $(examples_srcdir)/hello_interface.h
diff --git a/tests/examples/hello_interface.h b/tests/examples/hello_interface.h
index 58483e6ff..183a22c54 100644
--- a/tests/examples/hello_interface.h
+++ b/tests/examples/hello_interface.h
@@ -1,6 +1,6 @@
 #include "plugin.h"
 
 CINELERRA_INTERFACE(hello, 1,
-                    CINELERRA_INTERFACE_PROTO(void, hello, (void)),
-                    CINELERRA_INTERFACE_PROTO(void, goodbye, (const char*)),
+                    CINELERRA_INTERFACE_PROTO(void, hello, (void))
+                    CINELERRA_INTERFACE_PROTO(void, goodbye, (const char*))
                     );
diff --git a/tests/examples/plugin_main.c b/tests/examples/plugin_main.c
index 1902fc5fe..427f88655 100644
--- a/tests/examples/plugin_main.c
+++ b/tests/examples/plugin_main.c
@@ -12,20 +12,22 @@ main(int argc, char** argv)
     open both try them, close them.
   */
 
-  struct hello_interface_1* hello_de =
-    cinelerra_interface_open ("hello_1", "german_1", sizeof(struct hello_interface_1));
-  if (!hello_de) CINELERRA_DIE;
+  TODO("macros, doing casting and typing");
 
-  hello_de->say_hello();
+  CINELERRA_INTERFACE_TYPE(hello, 1)* hello_de = (CINELERRA_INTERFACE_TYPE(hello, 1)*)
+    cinelerra_interface_open ("hello_1", "german_1", sizeof(CINELERRA_INTERFACE_TYPE(hello, 1)));
+  TODO("new error handling, when finished  if (!hello_de) CINELERRA_DIE");
+
+  hello_de->hello();
 
 
-  struct hello_interface_1* hello_en =
-    cinelerra_interface_open ("hello_1", "english_1", sizeof(struct hello_interface_1));
-  if (!hello_en) CINELERRA_DIE;
+  //  struct hello_interface_1* hello_en =
+  //  cinelerra_interface_open ("hello_1", "english_1", sizeof(struct hello_interface_1));
+  // TODO if (!hello_en) CINELERRA_DIE;
 
-  hello_en->say_hello();
+  //hello_en->hello();
 
-  cinelerra_interface_close (hello_en);
+  //cinelerra_interface_close (hello_en);
   cinelerra_interface_close (hello_de);
 
 #if 0