From 449974ca6148c67b7167c856b5fb102847ef644e Mon Sep 17 00:00:00 2001
From: Daniel Hahler <git@thequod.de>
Date: Mon, 4 Apr 2016 20:04:19 +0200
Subject: [PATCH] luaA_checkscreen: display number of existing screens with
 error

This is meant to be helpful in the case of 0 existing screens, e.g.
during executing the config initially.
---
 objects/screen.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/objects/screen.c b/objects/screen.c
index c7e508b71..c4a0ee586 100644
--- a/objects/screen.c
+++ b/objects/screen.c
@@ -107,7 +107,8 @@ luaA_checkscreen(lua_State *L, int sidx)
     {
         int screen = lua_tointeger(L, sidx);
         if(screen < 1 || screen > globalconf.screens.len)
-            luaL_error(L, "invalid screen number: %d", screen);
+            luaL_error(L, "invalid screen number: %d (of %d existing)",
+                    screen, globalconf.screens.len);
         return globalconf.screens.tab[screen - 1];
     } else
         return luaA_checkudata(L, sidx, &screen_class);