diff --git a/Parser/tokenizer.c b/Parser/tokenizer.c
index d7a223a..aaed637 100644
--- a/Parser/tokenizer.c
+++ b/Parser/tokenizer.c
@@ -346,7 +346,8 @@
 	PyObject* utf8;
 	PyObject* buf = tok->decoding_buffer;
 	if (buf == NULL) {
-		PyObject *args = PyTuple_New(0);
+		/* Ask for one less byte so we can terminate it */
+		PyObject *args = Py_BuildValue("(i)", size-1);
 		if (args == NULL)
 			return error_ret(tok);
 		buf = PyObject_Call(tok->decoding_readline, args, NULL);