constant ROOMS_OPTION_MANDATORY in Rooms - Drupal Booking for Hotels, B&Bs and Vacation Rentals 7
4 uses of ROOMS_OPTION_MANDATORY
- book_units_per_type_form in modules/rooms_booking_manager/ rooms_booking_manager.module 
- Book units per type booking form callback.
- book_unit_form_builder in modules/rooms_booking_manager/ rooms_booking_manager.module 
- The form builder builds the form (where visible is simply the purchase button) for individual bookable units.
- rooms_booking_edit_form in modules/rooms_booking/ rooms_booking.admin.inc 
- Form callback: create or edit a booking.
- _rooms_booking_manager_add_options in modules/rooms_booking_manager/ rooms_booking_manager.units_per_type_form.inc 
- Checks if there are any options to add to units and loads them if so.
File
- ./rooms.module, line 48 
- Provides basic underlying functionality and configuration options used by all Rooms modules
Code
define('ROOMS_OPTION_MANDATORY', 'mandatory');