diff --git a/src/FlowSrc.cc b/src/FlowSrc.cc
index e97ad8eb25..fe3fa91ebe 100644
--- a/src/FlowSrc.cc
+++ b/src/FlowSrc.cc
@@ -12,6 +12,7 @@
 #include "FlowSrc.h"
 #include "Net.h"
 #include "netflow_pac.h"
+#include <errno.h>
 
 FlowSrc::FlowSrc()
 	{ // TODO: v9.