diff --git a/jxgrabkey/JXGrabKey/C++/src/JXGrabKey.cpp b/jxgrabkey/JXGrabKey/C++/src/JXGrabKey.cpp
index 7283a86..6379597 100644
--- a/jxgrabkey/JXGrabKey/C++/src/JXGrabKey.cpp
+++ b/jxgrabkey/JXGrabKey/C++/src/JXGrabKey.cpp
@@ -29,6 +29,7 @@
 #include <iostream>
 #include <sstream>
 #include <vector>
+#include <unistd.h>
 
 using namespace std;