diff --git a/source/client/player/input/TouchAreaModel.cpp b/source/client/player/input/TouchAreaModel.cpp
index 4c374ee..178efaf 100644
--- a/source/client/player/input/TouchAreaModel.cpp
+++ b/source/client/player/input/TouchAreaModel.cpp
@@ -6,6 +6,8 @@
 	SPDX-License-Identifier: BSD-1-Clause
  ********************************************************************/
 
+#include <cstddef>
+
 #include "TouchAreaModel.hpp"
 
 TouchAreaModel::~TouchAreaModel()