diff --git a/fwbuilder/src/libfwbuilder/src/fwbuilder/ThreadTools.h b/fwbuilder/src/libfwbuilder/src/fwbuilder/ThreadTools.h
index a8e4b03..f5722ea 100644
--- a/fwbuilder/src/libfwbuilder/src/fwbuilder/ThreadTools.h
+++ b/fwbuilder/src/libfwbuilder/src/fwbuilder/ThreadTools.h
@@ -27,6 +27,8 @@
 #ifndef __THREAD_TOOLS_H_FLAG__
 #define __THREAD_TOOLS_H_FLAG__
 
+#include <unistd.h>
+
 #include "fwbuilder/libfwbuilder-config.h"
 
 #include <time.h> //for time_t definition