diff --git a/pidof.c b/pidof.c
index dd85741..690052d 100644
--- a/pidof.c
+++ b/pidof.c
@@ -6,6 +6,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <limits.h>
 #include "proc.h"
 #include "util.h"