diff --git a/src/drivers/win/keyboard.cpp b/src/drivers/win/keyboard.cpp
index dba5b46c..8265c0ec 100644
--- a/src/drivers/win/keyboard.cpp
+++ b/src/drivers/win/keyboard.cpp
@@ -86,7 +86,7 @@ void KeyboardUpdateState(void)
 		else
 			keys_nr[i] = 0; // deactivate key
 
-	memcpy(keys,keys_nr,256);
+	memcpy(keys,keys_nr,sizeof(keys));
 
 	// key-down detection
 	for(int i = 0 ; i < 256 ; i++)