diff --git a/ext/continuation/continuation.c b/ext/continuation/continuation.c
index 71b52db539..c678371cca 100644
--- a/ext/continuation/continuation.c
+++ b/ext/continuation/continuation.c
@@ -6,6 +6,8 @@ void ruby_Init_Continuation_body(void);
 void
 Init_continuation(void)
 {
+#ifndef RUBY_EXPORT
     rb_warn("callcc is obsolete; use Fiber instead");
+#endif
     ruby_Init_Continuation_body();
 }