diff --git a/Include/codecs.h b/Include/codecs.h
index 611964c..b3088e4 100644
--- a/Include/codecs.h
+++ b/Include/codecs.h
@@ -49,6 +49,10 @@
 PyAPI_FUNC(PyObject *) _PyCodec_Lookup(
        const char *encoding
        );
+
+PyAPI_FUNC(int) _PyCodec_Forget(
+       const char *encoding
+       );
 #endif
 
 /* Codec registry encoding check API.