diff --git a/include/rudp/time.h b/include/rudp/time.h
index cbe781b..8c999f1 100644
--- a/include/rudp/time.h
+++ b/include/rudp/time.h
@@ -27,6 +27,7 @@
 
 #include <stdint.h>
 #include <sys/time.h>
+#include <stdlib.h>
 
 /**
    @this is an abstract time type definition.  It contains miliseconds