Index: tcc4tcl.tcl
==================================================================
--- tcc4tcl.tcl
+++ tcc4tcl.tcl
@@ -186,11 +186,11 @@
 					}
 					ok {
 						set return_failure "return(TCL_ERROR)"
 					}
 					double - float {
-						set return_failure "return(NaN)"
+						set return_failure "return(($rtype) ((($rtype) 1.0) / (($rtype) 0.0)))"
 					}
 					default {
 						set return_failure "return(NULL)"
 					}
 				}