diff --git a/test/dtypes.c b/test/dtypes.c
index acfda55e05..20743bddac 100644
--- a/test/dtypes.c
+++ b/test/dtypes.c
@@ -99,6 +99,7 @@ static herr_t convert_opaque(hid_t UNUSED st, hid_t UNUSED dt,
                size_t UNUSED bkg_stride, void UNUSED *_buf,
 	       void UNUSED *bkg, hid_t UNUSED dset_xfer_plid);
 static int opaque_long(void);
+static int opaque_funcs(void);
 
 
 /*-------------------------------------------------------------------------