diff --git a/lib/com_err/com_right.h b/lib/com_err/com_right.h
index b0857d283..7741684f0 100644
--- a/lib/com_err/com_right.h
+++ b/lib/com_err/com_right.h
@@ -58,6 +58,7 @@
 
 #ifdef __STDC__
 #include <stdarg.h>
+#include <stddef.h>
 #endif
 
 struct error_table {