This clear all cache function works in a similar manner as the cache clearing in the backend, but takes a more straightforward approach and the according backend hooks are not executed.
This method can throw a fatal error if a broken extension is loaded. If you get a white page or a PHP error message, check your system with the broken extension test below.
This clears the complete opcode caches of the active opcode cache systems, if the system supports reset.
Available PHP opcode cache systems