PHP: how to avoid redeclaring functions?

Question

I tend to get errors such as:

Fatal error: Cannot redeclare get_raw_data_list() (previously declared in /var/www/codes/handlers/make_a_thread/get_raw_

Answer 1

if(!function_exists("get_raw_data_list")) {
... define function here ...
}

http://us.php.net/function_exists