diff --git a/source/gui/widgets/slider.cpp b/source/gui/widgets/slider.cpp
index 7cda9e61..28f6dcd5 100644
--- a/source/gui/widgets/slider.cpp
+++ b/source/gui/widgets/slider.cpp
@@ -1,5 +1,6 @@
 
 #include <nana/gui/widgets/slider.hpp>
+#include <cstring>	//memcpy
 
 namespace nana
 {