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_data_list.php:7) in /var/www/codes/handlers/make_a_thread/get_raw_data_list.php on line 19
how can I avoid the error? Is it possible to create a IF-clause to check whether a function is declared before declaring it?
Use require_once or include_once as opposed to include or require when including the files that contain your functions.
The _once siblings of include and require will force PHP to check if the file has already been included/required, and if so, not include/require it again, thereby preventing 'cannot redeclare x function...' fatal errors.
if(!function_exists("get_raw_data_list")) {
... define function here ...
}
"function_exists" will tell you if a function has already been declared. Though I suspect maybe you have a problem with including files more than once. When you include a file are you using require_once or include_once or just require / include?
If you are dealing with Classes method_exists() might be what you're looking for:
if(!method_exists(__CLASS__, 'function_name')){
function function_name(){
}
}
This will check the current Class to make that the function function_name doesn't exist before trying to declare it
来源：https://stackoverflow.com/questions/1384006/php-how-to-avoid-redeclaring-functions