field_info_instance_settings($type) Returns a field type's default instance settings. Read more about field_info_instance_settings($type)
field_info_field_types($field_type) Return info from calling hook_field_info(). Read more about field_info_field_types($field_type)
_field_write_instance($instance, $update = FALSE) Stores an instance record in the field configuration database. Read more about _field_write_instance($instance, $update = FALSE)
_field_info_collate_types($reset = FALSE) Collate and return information from hook_field_info, hook_field_widget_info, hook_field_formatter_info and hook_field_storage_info. Cache the results. Read more about _field_info_collate_types($reset = FALSE)
