Index: Makefile
==================================================================
--- Makefile
+++ Makefile
@@ -5,12 +5,15 @@
 	mv example.c.new example.c
 
 example.o: example.c xvfs-core.h Makefile
 	cc -fPIC -Wall -I. -o example.o -c example.c
 
-example.so: example.o Makefile
-	cc -fPIC -shared -o example.so example.o
+xvfs-core.o: xvfs-core.c xvfs-core.h Makefile
+	cc -fPIC -Wall -I. -o xvfs-core.o -c xvfs-core.c
+
+example.so: example.o xvfs-core.o Makefile
+	cc -fPIC -shared -o example.so example.o xvfs-core.o
 
 test: example.so
 	echo 'load ./example.so Xvfs_example; puts OK' | tclsh | grep '^OK$$'
 
 clean:

Index: xvfs-core.c
==================================================================
--- xvfs-core.c
+++ xvfs-core.c
@@ -0,0 +1,7 @@
+#include <xvfs-core.h>
+#include <tcl.h>
+
+int Xvfs_Register(Tcl_Interp *interp, const char *fsName, int protocolVersion, xvfs_proc_getChildren_t getChildrenProc, xvfs_proc_getData_t getData) {
+	Tcl_SetResult(interp, "Not implemented", NULL);
+	return(TCL_ERROR);
+}

Index: xvfs-core.h
==================================================================
--- xvfs-core.h
+++ xvfs-core.h
@@ -6,8 +6,8 @@
 #define XVFS_PROTOCOL_VERSION 1
 
 typedef const char **(*xvfs_proc_getChildren_t)(const char *path, Tcl_WideInt limit);
 typedef const unsigned char *(*xvfs_proc_getData_t)(const char *path, Tcl_WideInt start, Tcl_WideInt length);
 
-int Xvfs_Register(const char *fsName, int protocolVersion, xvfs_proc_getChildren_t getChildrenProc, xvfs_proc_getData_t getData);
+int Xvfs_Register(Tcl_Interp *interp, const char *fsName, int protocolVersion, xvfs_proc_getChildren_t getChildrenProc, xvfs_proc_getData_t getData);
 
 #endif

Index: xvfs.c.rvt
==================================================================
--- xvfs.c.rvt
+++ xvfs.c.rvt
@@ -27,14 +27,14 @@
 
 static const unsigned char *xvfs_<?= $::xvfs::fsName ?>_getData(const char *path, Tcl_WideInt start, Tcl_WideInt length) {
 	return(NULL);
 }
 
-int Xvfs_<?= $::xvfs::fsName ?>_Init() {
+int Xvfs_<?= $::xvfs::fsName ?>_Init(Tcl_Interp *interp) {
 	int register_ret;
 	
-	register_ret = Xvfs_Register("<?= $::xvfs::fsName ?>", XVFS_PROTOCOL_VERSION, xvfs_<?= $::xvfs::fsName ?>_getChildren, xvfs_<?= $::xvfs::fsName ?>_getData);
+	register_ret = Xvfs_Register(interp, "<?= $::xvfs::fsName ?>", XVFS_PROTOCOL_VERSION, xvfs_<?= $::xvfs::fsName ?>_getChildren, xvfs_<?= $::xvfs::fsName ?>_getData);
 	if (register_ret != TCL_OK) {
 		return(register_ret);
 	}
 	
 	return(TCL_OK);