diff --git a/exl/linking.fzs b/exl/linking.fzs
index a2e2396..513aee3 100644
--- a/exl/linking.fzs
+++ b/exl/linking.fzs
@@ -1,8 +1,11 @@
 extern "libglfw" {
-  type GLFWwindow  = handle;
-  type GLFWmonitor = handle;
 
-  struct GLFWvidmode {
+  // Opaque types
+  type GLFWwindow  handle;
+  type GLFWmonitor handle;
+
+  // Struct definition
+  type GLFWvidmode struct {
     int width;
     int height;
     int redBits;
@@ -12,7 +15,7 @@ extern "libglfw" {
   }
 
   /// GLFWvidmode*
-  type GLFWvidmodeRef = ref GLFWvidmode;
+  type GLFWvidmodeRef ref GLFWvidmode;
 
   /// Create window with specified [width], [height] and [title]
   fn glfw_mkWindow(