vb.org Archive - session expire code question

I have hacked my /includes/functions_login.php script to provide sitewide login control using the vB db and cookies. It works quite nicely so far.

I want to check that when a user session expires, vB does actually go and delete my custom "username" cookie, and not just when a deliberate logout is performed (which I know does work). Can someone direct me to the required code for managing the automatic ending of a user session (and esp. deleting the cookies)? It doesn't seem to be in functions_login.php but maybe I'm missing something.

Thanks in advance. :)

X vBulletin 3.8.12 by vBS Debug Information
Template Usage: (1)ad_footer_end (1)ad_footer_start (1)ad_header_end (1)ad_header_logo (1)ad_navbar_below (1)footer (1)gobutton (1)header (1)headinclude (6)option (1)post_thanks_navbar_search (1)printthread (1)printthreadbit (1)spacer_close (1)spacer_open Phrase Groups Available: global postbit showthread	Included Files: ./printthread.php ./global.php ./includes/init.php ./includes/class_core.php ./includes/config.php ./includes/functions.php ./includes/class_hook.php ./includes/modsystem_functions.php ./includes/class_bbcode_alt.php ./includes/class_bbcode.php ./includes/functions_bigthree.php Hooks Called: init_startup init_startup_session_setup_start init_startup_session_setup_complete cache_permissions fetch_threadinfo_query fetch_threadinfo fetch_foruminfo style_fetch cache_templates global_start parse_templates global_setup_complete printthread_start bbcode_fetch_tags bbcode_create bbcode_parse_start bbcode_parse_complete_precache bbcode_parse_complete printthread_post printthread_complete
Messages:

X vBulletin 3.8.12 by vBS Debug Information

Page Generation 0.00919 seconds
Memory Usage 1,698KB
Queries Executed 10 (?)

More Information

Template Usage:

(1)ad_footer_end
(1)ad_footer_start
(1)ad_header_end
(1)ad_header_logo
(1)ad_navbar_below
(1)footer
(1)gobutton
(1)header
(1)headinclude
(6)option
(1)post_thanks_navbar_search
(1)printthread
(1)printthreadbit
(1)spacer_close
(1)spacer_open

Phrase Groups Available:

global
postbit
showthread

Included Files:

./printthread.php
./global.php
./includes/init.php
./includes/class_core.php
./includes/config.php
./includes/functions.php
./includes/class_hook.php
./includes/modsystem_functions.php
./includes/class_bbcode_alt.php
./includes/class_bbcode.php
./includes/functions_bigthree.php

Hooks Called:

init_startup
init_startup_session_setup_start
init_startup_session_setup_complete
cache_permissions
fetch_threadinfo_query
fetch_threadinfo
fetch_foruminfo
style_fetch
cache_templates
global_start
parse_templates
global_setup_complete
printthread_start
bbcode_fetch_tags
bbcode_create
bbcode_parse_start
bbcode_parse_complete_precache
bbcode_parse_complete
printthread_post
printthread_complete

Messages:

X vBulletin 3.8.12 by vBS Debug Information
Page Generation 0.00919 seconds Memory Usage 1,698KB Queries Executed 10 (?)
More Information
Template Usage: (1)ad_footer_end (1)ad_footer_start (1)ad_header_end (1)ad_header_logo (1)ad_navbar_below (1)footer (1)gobutton (1)header (1)headinclude (6)option (1)post_thanks_navbar_search (1)printthread (1)printthreadbit (1)spacer_close (1)spacer_open Phrase Groups Available: global postbit showthread	Included Files: ./printthread.php ./global.php ./includes/init.php ./includes/class_core.php ./includes/config.php ./includes/functions.php ./includes/class_hook.php ./includes/modsystem_functions.php ./includes/class_bbcode_alt.php ./includes/class_bbcode.php ./includes/functions_bigthree.php Hooks Called: init_startup init_startup_session_setup_start init_startup_session_setup_complete cache_permissions fetch_threadinfo_query fetch_threadinfo fetch_foruminfo style_fetch cache_templates global_start parse_templates global_setup_complete printthread_start bbcode_fetch_tags bbcode_create bbcode_parse_start bbcode_parse_complete_precache bbcode_parse_complete printthread_post printthread_complete
Messages: