How do I get threadid from showpost?

[vauge]

vB4.2

I'm creating a new plugin that needs the threadid of the thread the user is currently viewing.

I have read this article: https://vborg.vbsupport.ru/showthread.php?t=228078

I am unsure what to preregister for threadid and what variable to use on the template. The hook I've tried is at showthread_complete.

I have tried all kinds of different vars and none seem to work. Search function grabs all kinds of answers but I think I am trying them out of context.

$threadid
thread['$threadid]
{vb:raw thread.threadid}
{vb:raw threadid}

/head explodes.

Any ideas?