up when the file is loaded (compile-time) as PHP doesn't know if it's going to be declared or not until it's run (run-time). So, the opcodes can be cached, but the symbol table can't be loaded from cache until the function is run. Best source I can find is Rasmus in IRC: http://stackoverflow.com/a/1397160/2575 Thanks, -- Ryan McCue <http://ryanmccue.info/>