checking for a defined function

how can I do something like if(!defined(cybercash_encr())) dl("cybercash.so"); anyone know of a good way to see if a function/module has been included in php? I need a run time solution for a script to be encoder()ed and distributed, Thanks Eric -- Support your government, give Echelon / Carnivore something to parse -- classfield top-secret government restricted data information project CIA KGB GRU DISA DoD defense systems military systems spy steal terrorist Allah Natasha Gregori destroy destruct attack democracy will send Russia bank system compromise international own rule the world ATSC RTEM warmod ATMD force power enforce sensitive directorate TSP NSTD ORD DD2-N AMTAS STRAP warrior-T presidental elections policital foreign embassy takeover --------------------------------------------------------------------------