diff --git a/lib/command.h b/lib/command.h
index 66883fb..9e727cf 100644
--- a/lib/command.h
+++ b/lib/command.h
@@ -287,7 +287,7 @@
 void sort_node ();
 
 char *argv_concat (char **, int, int);
-vector cmd_make_strvec (char *);
+vector cmd_make_strvec (const char *);
 void cmd_free_strvec (vector);
 vector cmd_describe_command ();
 char **cmd_complete_command ();