diff --git a/vis/state.c b/vis/state.c
index 4214159f..bf9e513c 100644
--- a/vis/state.c
+++ b/vis/state.c
@@ -19,6 +19,7 @@
 
 #include <stdint.h>
 #include <stdio.h>
+#include <unistd.h>
 
 #include <vis/vis.h>
 #include <common/cmdlib.h>