static void *alloced_str;
-static LRESULT parent_wnd_notify(LPARAM lParam)
+#define forward_test_idFrom 0xabcd0002
+#define forward_test_code 0xabcd0003
+#define forward_test_return 0xabcd0004
+static _Bool forward_test;
+static const NMHDR forward_test_nmhdr = {
Rename forward_test_nmhdr to test_WM_NOTIFY_forwarding_nmhdr. And put the `{` on a newline.