diff --git a/example/x11.c b/example/x11.c
index 8d452715..dd01b3bc 100644
--- a/example/x11.c
+++ b/example/x11.c
@@ -10,6 +10,7 @@
 #include <sys/ioctl.h>
 #include <netinet/in.h>
 #include <sys/socket.h>
+#include <sys/select.h>
 #include <arpa/inet.h>
 #include <unistd.h>
 #include <sys/types.h>