diff --git a/sample-input/bindings.rs b/sample-input/bindings.rs
index c92e04e..d5bf4cb 100644
--- a/sample-input/bindings.rs
+++ b/sample-input/bindings.rs
@@ -628,7 +628,7 @@ impl webrender_traits::RenderNotifier for CppNotifier {
 }
 
 #[no_mangle]
-pub extern fn wr_renderer_set_external_image_handler(renderer: &mut Renderer,
+pub extern "C" fn wr_renderer_set_external_image_handler(renderer: &mut WrRenderer,
                                                      external_image_handler: *mut WrExternalImageHandler) {
     if !external_image_handler.is_null() {
         renderer.set_external_image_handler(Box::new(