diff --git a/packages/PLStream/pl-incl.h b/packages/PLStream/pl-incl.h
index 6b1f38abf..718b446d1 100755
--- a/packages/PLStream/pl-incl.h
+++ b/packages/PLStream/pl-incl.h
@@ -626,6 +626,7 @@ extern word lookupAtom(const char *s, size_t len);
 extern atom_t	lookupUCSAtom(const pl_wchar_t *s, size_t len);
 extern int toIntegerNumber(Number n, int flags);
 extern int get_atom_ptr_text(Atom a, PL_chars_t *text);
+extern int warning(const char *fm, ...);
 
 /**** stuff from pl-files.c ****/
 void initFiles(void);
diff --git a/packages/PLStream/pl-yap.c b/packages/PLStream/pl-yap.c
index f5d04129a..25a9d2c8c 100644
--- a/packages/PLStream/pl-yap.c
+++ b/packages/PLStream/pl-yap.c
@@ -596,3 +596,15 @@ X_API int PL_handle_signals(void)
   return 0;
 }
 
+/* just a stub for now */
+int
+warning(const char *fm, ...)
+{  va_list args;
+
+  va_start(args, fm);
+  fprintf(stderr,"warning: %s\n", fm);
+  va_end(args);
+
+  return TRUE;
+}
+