diff --git a/appl/login/login_locl.h b/appl/login/login_locl.h
index ad2de8ca3..f0c161ddb 100644
--- a/appl/login/login_locl.h
+++ b/appl/login/login_locl.h
@@ -47,6 +47,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <ctype.h>
 #include <unistd.h>
 #include <syslog.h>
 #include <signal.h>