diff --git a/src/fd_monitor.cpp b/src/fd_monitor.cpp
index a55e9c55f..2ed2ca4de 100644
--- a/src/fd_monitor.cpp
+++ b/src/fd_monitor.cpp
@@ -4,6 +4,7 @@
 #include "fd_monitor.h"
 
 #include <cstring>
+#include <thread> //this_thread::sleep_for
 
 #include "flog.h"
 #include "io.h"