1 files changed, 1 insertions, 0 deletions

diff --git a/xutil.h b/xutil.h
index 337a190..03aa6cf 100644
--- a/xutil.h
+++ b/xutil.h
@@ -1,6 +1,7 @@
 #pragma once
 
 #include <functional>
+#include <optional>
 #include <X11/Xlib.h>