diff --git a/include/icsneo/icsneolegacy.h b/include/icsneo/icsneolegacy.h
index 3988382..e71173d 100644
--- a/include/icsneo/icsneolegacy.h
+++ b/include/icsneo/icsneolegacy.h
@@ -5,6 +5,7 @@
 #include "icsneo/platform/tchar.h"
 
 #include <stdint.h>
+#include <stddef.h>
 typedef uint8_t byte; // Typedef helper for the following include
 #include "icsneo/icsnVC40.h" // Definitions for structs
 
@@ -166,4 +167,4 @@ extern int LegacyDLLExport icsneoDisableBitSmash(void* hObject, unsigned int res
 } // extern "C"
 #endif
 
-#endif
\ No newline at end of file
+#endif