Rustup

src/win32/callback.rs

@@ -36,8 +36,9 @@ fn send_event(input_window: winapi::HWND, event: Event) {
 /// This is the callback that is called by `DispatchMessage` in the events loop.
 /// 
 /// Returning 0 tells the Win32 API that the message has been processed.
-pub extern "system" fn callback(window: winapi::HWND, msg: winapi::UINT,
-    wparam: winapi::WPARAM, lparam: winapi::LPARAM) -> winapi::LRESULT
+pub unsafe extern "system" fn callback(window: winapi::HWND, msg: winapi::UINT,
+                                       wparam: winapi::WPARAM, lparam: winapi::LPARAM)
+                                       -> winapi::LRESULT
 {
     match msg {
         winapi::WM_DESTROY => {