diff --git a/man7/aio.7 b/man7/aio.7
index 13958d718..45d566b53 100644
--- a/man7/aio.7
+++ b/man7/aio.7
@@ -246,6 +246,7 @@ aio_return():
 .SS Program source
 \&
 .nf
+#include <fcntl.h>
 #include <stdlib.h>
 #include <unistd.h>
 #include <stdio.h>