diff --git a/Examples/test-suite/register_par.i b/Examples/test-suite/register_par.i
index 643841455..3be1c7ea0 100644
--- a/Examples/test-suite/register_par.i
+++ b/Examples/test-suite/register_par.i
@@ -4,6 +4,18 @@
 struct swig_tree;
 %}
 
+%{
+#if defined(__cplusplus)
+#if __cplusplus >= 201703L
+/*
+Fix for languages that compile C tests as C++:
+  error: ISO C++17 does not allow ‘register’ storage class specifier [-Werror=register]
+*/
+#define register
+#endif
+#endif
+%}
+
 // bug # 924413
 %inline {
   void clear_tree_flags(register struct swig_tree *tp, register int i) {}