--- interface/tk_c.c.ORIG	2011-12-03 16:49:19.000000000 +0100
+++ interface/tk_c.c	2013-01-29 10:35:09.308264734 +0100
@@ -913,7 +913,7 @@
 	vsnprintf(buf, sizeof(buf), fmt, ap);
 	Tcl_Eval(my_interp, buf);
 	va_end(ap);
-	return my_interp->result;
+	return Tcl_GetStringResult(my_interp);
 }
 
 static const char *v_get2(const char *v1, const char *v2)