echo "<pre>";
print_r(get_defined_functions());
echo "</pre>";
/*
run:
Array
(
[internal] => Array
(
[0] => zend_version
[1] => func_num_args
[2] => func_get_arg
[3] => func_get_args
[4] => strlen
[5] => strcmp
[6] => strncmp
[7] => strcasecmp
[8] => strncasecmp
[9] => each
[10] => error_reporting
[11] => define
[12] => defined
[13] => get_class
[14] => get_called_class
[15] => get_parent_class
[16] => method_exists
[17] => property_exists
[18] => class_exists
[19] => interface_exists
[20] => trait_exists
[21] => function_exists
[22] => class_alias
[23] => get_included_files
[24] => get_required_files
[25] => is_subclass_of
[26] => is_a
[27] => get_class_vars
[28] => get_object_vars
[29] => get_class_methods
[30] => trigger_error
[31] => user_error
[32] => set_error_handler
[33] => restore_error_handler
[34] => set_exception_handler
[35] => restore_exception_handler
[36] => get_declared_classes
[37] => get_declared_traits
[38] => get_declared_interfaces
[39] => get_defined_functions
[40] => get_defined_vars
[41] => create_function
[42] => get_resource_type
[43] => get_loaded_extensions
[44] => extension_loaded
[45] => get_extension_funcs
[46] => get_defined_constants
[47] => debug_backtrace
[48] => debug_print_backtrace
[49] => gc_collect_cycles
[50] => gc_enabled
[51] => gc_enable
...
*/
