diff --git a/libretroshare/src/pqi/pqiqos.h b/libretroshare/src/pqi/pqiqos.h
index e3e665425..3eaa4e863 100644
--- a/libretroshare/src/pqi/pqiqos.h
+++ b/libretroshare/src/pqi/pqiqos.h
@@ -35,6 +35,7 @@
 #pragma once
 
 #include <stdint.h>
+#include <stdlib.h>
 #include <vector>
 #include <list>