diff --git a/apm.c b/apm.c
index 2c0fecf..477a3c8 100644
--- a/apm.c
+++ b/apm.c
@@ -4,6 +4,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <sys/resource.h>
 #include <sys/stat.h>
 #include <time.h>
 #include <unistd.h>