[NTLDR]

In this case, the forum table has an options column which contains a single number which can be used to work out what options are set, like use of smilies, vBcode, HTML etc.

Adding another bitfield to the array in init.php that defines your specific option and editing the code that changes the option in forum.php will allow to to check if the bit for your option is set, for example:

PHP Code:

if ($forum['options'] & CANHAVEATTACHMENTS) {
    // this forum can have attachments, place code here
} else {
    // this forum can't have attachments
} 


CANHAVEATTACHMENTS would be defined in the $_FORUMOPTIONS array in init.php and is then defined as a constant later on.

I didn't understand these at all when vB3 first came out but after reading a post on vB.com and sort of seeing how they worked and then getting them working with my vBindex hack. They save alot of time when you understand them