diff --git a/fluid/fluid.cxx b/fluid/fluid.cxx
index 283788ff4..43c69cc41 100644
--- a/fluid/fluid.cxx
+++ b/fluid/fluid.cxx
@@ -48,6 +48,7 @@
 #if defined(WIN32) && !defined(__CYGWIN__)
 #  include <direct.h>
 #  include <windows.h>
+#  include <io.h>
 #else
 #  include <unistd.h>
 #endif