diff --git a/libaf/af_channels.c b/libaf/af_channels.c
index 9943e573aa..a84a0bd284 100644
--- a/libaf/af_channels.c
+++ b/libaf/af_channels.c
@@ -5,6 +5,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <unistd.h>
 
 #include "../config.h"
 #include "../mp_msg.h"