diff --git a/src/util.c b/src/util.c
index 5e17bcd..b3d5222 100644
--- a/src/util.c
+++ b/src/util.c
@@ -22,6 +22,7 @@
 #define __UTIL_C
 
 /* includes */
+#include <sys/file.h>
 #include "pmacct.h"
 #include "pmacct-data.h"
 #include "ip_flow.h"