diff --git a/Python/codecs.c b/Python/codecs.c
index c8926fc..5a0e488 100644
--- a/Python/codecs.c
+++ b/Python/codecs.c
@@ -354,7 +354,7 @@
             v = NULL;
             goto onError;
         }
-        v = PyString_FromStringAndSize(PyBytes_AS_STRING(v), Py_Size(v));
+        v = PyString_FromStringAndSize(PyBytes_AS_STRING(v), Py_SIZE(v));
     }
     else if (PyString_Check(v))
         Py_INCREF(v);