diff --git a/src/Common/Types.hpp b/src/Common/Types.hpp
index cd08ed5..837df46 100644
--- a/src/Common/Types.hpp
+++ b/src/Common/Types.hpp
@@ -151,7 +151,10 @@
 		return v;
 	}
 
-	#define OFFSET(s,m) (int)(size_t)&reinterpret_cast<const volatile char&>((((s*)0)->m))
+	// The OFFSET macro is a generalization of the offsetof() macro defined in <cstddef>.
+	// It allows e.g. getting the offset of array elements, even when indexed dynamically.
+	// We cast the address '32' and subtract it again, because null-dereference is undefined behavior.
+	#define OFFSET(s,m) ((int)(size_t)&reinterpret_cast<const volatile char&>((((s*)32)->m)) - 32)
 }
 
 #endif   // sw_Types_hpp