diff --git a/lib/isc/unix/ufile.c b/lib/isc/unix/ufile.c
index 437564d6d7..969353c280 100644
--- a/lib/isc/unix/ufile.c
+++ b/lib/isc/unix/ufile.c
@@ -16,7 +16,9 @@
  */
 
 #include <stdio.h>
+#include <stdlib.h>
 #include <unistd.h>
+
 #include <isc/ufile.h>
 
 FILE *