--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/runtime/internal/invariant.d	Thu Aug 21 15:19:45 2008 +0200
@@ -0,0 +1,25 @@
+
+/*
+ * Placed into the Public Domain
+ * written by Walter Bright
+ * www.digitalmars.com
+ */
+
+extern(C) void _d_invariant(Object o)
+{   ClassInfo c;
+
+    //printf("__d_invariant(%p)\n", o);
+
+    // BUG: needs to be filename/line of caller, not library routine
+    assert(o !is null);	// just do null check, not invariant check
+
+    c = o.classinfo;
+    do
+    {
+	if (c.classInvariant)
+	{
+	    (*c.classInvariant)(o);
+	}
+	c = c.base;
+    } while (c);
+}