diff --git a/source/wasm3.h b/source/wasm3.h
index 1cab94a..3867061 100644
--- a/source/wasm3.h
+++ b/source/wasm3.h
@@ -110,9 +110,9 @@ M3ImportContext, * IM3ImportContext;
 // -------------------------------------------------------------------------------------------------------------------------------
 
 # if defined(M3_IMPLEMENT_ERROR_STRINGS)
-#   define d_m3ErrorConst(LABEL, STRING)        M3Result m3Err_##LABEL = { STRING };
+#   define d_m3ErrorConst(LABEL, STRING)        extern const M3Result m3Err_##LABEL = { STRING };
 # else
-#   define d_m3ErrorConst(LABEL, STRING)        extern M3Result m3Err_##LABEL;
+#   define d_m3ErrorConst(LABEL, STRING)        extern const M3Result m3Err_##LABEL;
 # endif
 
 // -------------------------------------------------------------------------------------------------------------------------------