diff --git a/src/tag/GenParseName.cxx b/src/tag/GenParseName.cxx
index 9868d2e2f..70bbf7c39 100644
--- a/src/tag/GenParseName.cxx
+++ b/src/tag/GenParseName.cxx
@@ -19,6 +19,7 @@
 
 #include "Type.h"
 
+#include <cstdlib>
 #include <map>
 #include <string_view>