1 files changed, 8 insertions, 0 deletions
diff --git a/spec/ruby/optional/capi/ext/class_id_under_autoload_spec.c b/spec/ruby/optional/capi/ext/class_id_under_autoload_spec.c
index 64393a9397..cc5550f041 100644
--- a/spec/ruby/optional/capi/ext/class_id_under_autoload_spec.c
+++ b/spec/ruby/optional/capi/ext/class_id_under_autoload_spec.c
@@ -1,5 +1,13 @@
 #include "ruby.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 void Init_class_id_under_autoload_spec(void) {
   rb_define_class_id_under(rb_cObject, rb_intern("ClassIdUnderAutoload"), rb_cObject);
 }
+
+#ifdef __cplusplus
+}
+#endif