diff --git a/source/libtun/tunctl.c b/source/libtun/tunctl.c
index 42b611f..e8f7442 100644
--- a/source/libtun/tunctl.c
+++ b/source/libtun/tunctl.c
@@ -19,6 +19,7 @@
 #include<fcntl.h>
 #include<string.h>
 #include<sys/ioctl.h>
+#include<unistd.h>
 
 int createTun(char* interfaceName, int iffFlags)
 {