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;