--- a/src/gripes.cc	Sun Aug 30 10:32:10 2009 +0200
+++ b/src/gripes.cc	Sun Aug 30 21:48:19 2009 +0200
@@ -271,6 +271,13 @@
   error ("a cs-list cannot be further indexed");
 }
 
+void
+gripe_warn_complex_cmp (void)
+{
+  warning_with_id ("Octave:matlab-incompatible",
+                   "potential Matlab compatibility problem: comparing complex numbers");
+}
+
 /*
 ;;; Local Variables: ***
 ;;; mode: C++ ***