diff --git a/src/interfaces/ILogBackend.h b/src/interfaces/ILogBackend.h
index 30554905..6e3f5c1c 100644
--- a/src/interfaces/ILogBackend.h
+++ b/src/interfaces/ILogBackend.h
@@ -26,6 +26,7 @@
 
 
 #include <stdarg.h>
+#include <stddef.h>
 
 
 class ILogBackend