diff --git a/src/memory.hh b/src/memory.hh
index 7da3486e..a6752c78 100644
--- a/src/memory.hh
+++ b/src/memory.hh
@@ -2,6 +2,7 @@
 #define memory_hh_INCLUDED
 
 #include <cstdlib>
+#include <cstddef>
 
 #include "assert.hh"