There are several Apache directives that allow you to change the PHP configuration from within the Apache configuration files. For a listing of which directives are PHP_INI_ALL, PHP_INI_PERDIR, or PHP_INI_SYSTEM.
Sets the value of the specified directive. Can be used only with PHP_INI_ALL and PHP_INI_PERDIR type directives. To clear a previously set value use none as the value.
A handy trick to pick up parse errors in test_file.php if you can't set display_errors in php.ini or use .htaccess:
ini_set ('display_errors', true);