Index: generic/itclBase.c
==================================================================
--- generic/itclBase.c
+++ generic/itclBase.c
@@ -79,11 +79,11 @@
 static const char safeInitScript[] =
 "proc ::itcl::local {class name args} {\n"
 "    set ptr [uplevel [list $class $name] $args]\n"
 "    uplevel [list set itcl-local-$ptr $ptr]\n"
 "    set cmd [uplevel namespace which -command $ptr]\n"
-"    uplevel [list trace variable itcl-local-$ptr u \"::itcl::delete object $cmd; list\"]\n"
+"    uplevel [list trace add variable itcl-local-$ptr unset \"::itcl::delete object $cmd; list\"]\n"
 "    return $ptr\n"
 "}";
 
 static const char *clazzClassScript =
 "::oo::class create ::itcl::clazz {\n"

Index: library/itcl.tcl
==================================================================
--- library/itcl.tcl
+++ library/itcl.tcl
@@ -30,11 +30,11 @@
 # ----------------------------------------------------------------------
 proc ::itcl::local {class name args} {
     set ptr [uplevel [list $class $name] $args]
     uplevel [list set itcl-local-$ptr $ptr]
     set cmd [uplevel namespace which -command $ptr]
-    uplevel [list trace variable itcl-local-$ptr u \
+    uplevel [list trace add variable itcl-local-$ptr unset \
         "::itcl::delete_helper $cmd"]
     return $ptr
 }
 
 # ----------------------------------------------------------------------