diff --git a/lib/ipc/hi_locl.h b/lib/ipc/hi_locl.h
index 5163924c5..b9d2ce5ce 100644
--- a/lib/ipc/hi_locl.h
+++ b/lib/ipc/hi_locl.h
@@ -40,6 +40,7 @@
 
 #include <sys/poll.h>
 
+#include <ctype.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>