2 files changed, 26 insertions, 0 deletions
diff --git a/c_src/esdl2.h b/c_src/esdl2.h
index c7deb41..c64352e 100644
--- a/c_src/esdl2.h
+++ b/c_src/esdl2.h
@@ -152,6 +152,7 @@
 	F(create_window, 6) \
 	F(create_window_and_renderer, 3) \
 	F(get_window_brightness, 1) \
+	F(get_window_display_index, 1) \
 
 // Generated declarations for the NIF.
 
diff --git a/c_src/sdl_window.c b/c_src/sdl_window.c
index bc8221b..98c6aaf 100644
--- a/c_src/sdl_window.c
+++ b/c_src/sdl_window.c
@@ -126,3 +126,28 @@ NIF_FUNCTION(get_window_brightness)
 	return nif_thread_call(env, thread_get_window_brightness, 1,
 		NIF_RES_GET(Window, window_res));
 }
+
+// get_window_display_index
+
+NIF_CALL_HANDLER(thread_get_window_display_index)
+{
+	int i = SDL_GetWindowDisplayIndex(args[0]);
+
+	if (i < 0)
+		return sdl_error_tuple(env);
+
+	return enif_make_tuple2(env,
+		atom_ok,
+		enif_make_int(env, i)
+	);
+}
+
+NIF_FUNCTION(get_window_display_index)
+{
+	void* window_res;
+
+	BADARG_IF(!enif_get_resource(env, argv[0], res_Window, &window_res));
+
+	return nif_thread_call(env, thread_get_window_display_index, 1,
+		NIF_RES_GET(Window, window_res));
+}