diff --git a/xye/src/gen.cpp b/xye/src/gen.cpp

index 3515972..51f64f3 100644

--- a/xye/src/gen.cpp

+++ b/xye/src/gen.cpp

@@ -15,6 +15,7 @@ Permission is granted to anyone to use this software for any purpose, including

 */

+#include <unistd.h>

 #include "gen.h"

 #include "vxsdl.h"