request globals?

Hi, I'm trying to figure out the best way to save per-request data. My attempts to use a global HashTable are failing miserably at the first zend_hash_add() with a segfault, and it is clearly because the hashtable is not properly initialized, but I can't figure out where I'm going wrong. Before I plop a bunch of code here, are there some simple steps I should take to make sure that a per-request HashTable is functional? What I am trying to do is to store a per-request list of .phar files and their file manifest. Thanks, Greg