diff --git a/plugin/handler_socket/libhsclient/fatal.cpp b/plugin/handler_socket/libhsclient/fatal.cpp
index 8f8751da382..5cdd8879ab1 100644
--- a/plugin/handler_socket/libhsclient/fatal.cpp
+++ b/plugin/handler_socket/libhsclient/fatal.cpp
@@ -9,6 +9,7 @@
 #include <stdlib.h>
 #include <stdio.h>
 #include <syslog.h>
+#include <unistd.h>
 
 #include "fatal.hpp"