diff --git a/code/ryzom/client/src/client_sheets/stdpch.h b/code/ryzom/client/src/client_sheets/stdpch.h
index 1b3d2e146..53a1531be 100644
--- a/code/ryzom/client/src/client_sheets/stdpch.h
+++ b/code/ryzom/client/src/client_sheets/stdpch.h
@@ -16,6 +16,7 @@
 
 #include <nel/misc/types_nl.h>
 
+#include <stddef.h>
 #include <stdlib.h>
 #include <stdio.h>
 #include <math.h>