diff --git a/ixwebsocket/IXUrlParser.cpp b/ixwebsocket/IXUrlParser.cpp
index 9018f893..76683722 100644
--- a/ixwebsocket/IXUrlParser.cpp
+++ b/ixwebsocket/IXUrlParser.cpp
@@ -33,6 +33,7 @@
 
 #include <algorithm>
 #include <cstring>
+#include <cstdlib>
 
 namespace
 {