diff -r 540a9c69c2ea Modules/_tkinter.c
--- a/Modules/_tkinter.c	Fri Sep 13 19:53:08 2013 +0200
+++ b/Modules/_tkinter.c	Sun Sep 15 13:59:39 2013 +0300
@@ -1107,10 +1107,7 @@
         res = FromObj((PyObject*)self, value);
         Tcl_DecrRefCount(value);
     } else {
-        const char *s = Tcl_GetStringResult(self->interp);
-        const char *p = s;
-
-        res = PyUnicode_FromStringAndSize(s, (int)(p-s));
+        res = PyUnicode_FromString(Tcl_GetStringResult(self->interp));
     }
     return res;
 }