diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 7cfd359a659..7008541f2e5 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,9 @@
+2017-09-27  Tom Tromey  <tom@tromey.com>
+
+	* command.h (not_just_help_class_command): Update.
+	* cli/cli-decode.h (not_just_help_class_command): Update.
+	* cli/cli-decode.c (not_just_help_class_command): Constify.
+
 2017-09-27  Tom Tromey  <tom@tromey.com>
 
 	* gdb_bfd.c (maintenance_info_bfds): Constify.
diff --git a/gdb/cli/cli-decode.c b/gdb/cli/cli-decode.c
index 257a9c4a808..f161c86ebc8 100644
--- a/gdb/cli/cli-decode.c
+++ b/gdb/cli/cli-decode.c
@@ -440,7 +440,7 @@ add_abbrev_prefix_cmd (const char *name, enum command_class theclass,
 
 /* This is an empty "cfunc".  */
 void
-not_just_help_class_command (char *args, int from_tty)
+not_just_help_class_command (const char *args, int from_tty)
 {
 }
 
diff --git a/gdb/cli/cli-decode.h b/gdb/cli/cli-decode.h
index 691bfe3f8fc..76f3ca9d7aa 100644
--- a/gdb/cli/cli-decode.h
+++ b/gdb/cli/cli-decode.h
@@ -228,7 +228,7 @@ extern void apropos_cmd (struct ui_file *, struct cmd_list_element *,
    function field NULL, the command is interpreted as a help topic, or
    as a class of commands.  */
 
-extern void not_just_help_class_command (char *arg, int from_tty);
+extern void not_just_help_class_command (const char *arg, int from_tty);
 
 /* Exported to cli/cli-setshow.c */
 
diff --git a/gdb/command.h b/gdb/command.h
index 3a6c58961ad..b40cd7e4968 100644
--- a/gdb/command.h
+++ b/gdb/command.h
@@ -459,7 +459,7 @@ extern scoped_restore_tmpl<int> prevent_dont_repeat (void);
    function field NULL, the command is interpreted as a help topic, or
    as a class of commands.  */
 
-extern void not_just_help_class_command (char *, int);
+extern void not_just_help_class_command (const char *, int);
 
 /* Check function pointer.  */
 extern int cmd_func_p (struct cmd_list_element *cmd);