diff --git a/src/sysdep.c b/src/sysdep.c
index e868bc9c499..ac9853a724f 100644
--- a/src/sysdep.c
+++ b/src/sysdep.c
@@ -2319,7 +2319,7 @@ read_input_waiting ()
 
       /* Scan the chars for C-g and store them in kbd_buffer.  */
       e.kind = ascii_keystroke;
-      e.frame_or_window = selected_frame;
+      XSETFRAME (e.frame_or_window, selected_frame);
       e.modifiers = 0;
       for (i = 0; i < nread; i++)
 	{