diff --git a/client/ui.h b/client/ui.h
index 14af52fcb..ca235c11f 100644
--- a/client/ui.h
+++ b/client/ui.h
@@ -17,6 +17,7 @@
 #include <stdio.h>
 #include <stdbool.h>
 #include <stdint.h>
+#include <string.h>
 #include <readline/readline.h>
 #include <pthread.h>
 #include <math.h>