diff --git a/assa/CommonUtils.h b/assa/CommonUtils.h
index 2db38d2..4db27f6 100644
--- a/assa/CommonUtils.h
+++ b/assa/CommonUtils.h
@@ -16,6 +16,7 @@
 
 #include <sstream>
 
+#include <unistd.h>
 #include <string> 
 #include <vector>
 using std::vector;