text: /* Copyright (c) 2010 Wildfire Games
   *
   * Permission is hereby granted, free of charge, to any person obtaining
   * a copy of this software and associated documentation files (the
   * "Software"), to deal in the Software without restriction, including
   * without limitation the rights to use, copy, modify, merge, publish,
   * distribute, sublicense, and/or sell copies of the Software, and to
   * permit persons to whom the Software is furnished to do so, subject to
   * the following conditions:
   * 
   * The above copyright notice and this permission notice shall be included
   * in all copies or substantial portions of the Software.
   * 
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
   * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
   * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
   * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
   * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
   * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
   * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
   */
  
  /*
   * helpers for module initialization/shutdown.
   */
  
  #ifndef INCLUDED_MODULE_INIT
  #define INCLUDED_MODULE_INIT
  
  /**
   * initialization state of a module (class, source file, etc.)
   * must be initialized to zero (e.g. by defining as a static variable).
   * DO NOT change the value!
   **/
  typedef intptr_t ModuleInitState;	// intptr_t is required by cpu_CAS
  
  /**
   * calls a user-defined init function if initState is zero.
   *
   * @return INFO::SKIPPED if already initialized, a Status if the
   * previous invocation failed, or the value returned by the callback.
   *
   * postcondition: initState is "initialized" if the callback returned
   * INFO::OK, otherwise its Status return value (which prevents
   * shutdown from being called).
   *
   * thread-safe: subsequent callers spin until the callback returns
   * (this prevents using partially-initialized modules)
   *
   * note that callbacks typically reference static data and thus do not
   * require a function argument, but that can later be added if necessary.
   **/
  LIB_API Status ModuleInit(volatile ModuleInitState* initState, Status (*init)());
  
  /**
   * calls a user-defined shutdown function if initState is "initialized".
   *
   * @return INFO::OK if shutdown occurred, INFO::SKIPPED if initState was
   * zero (uninitialized), otherwise the Status returned by ModuleInit.
   *
   * postcondition: initState remains set to the Status, or has been
   * reset to zero to allow multiple init/shutdown pairs, e.g. in self-tests.
   *
   * note: there is no provision for reference-counting because that
   * turns out to be problematic (a user might call shutdown immediately
   * after init; if this is the first use of the module, it will
   * be shutdown prematurely, which is at least inefficient and
   * possibly dangerous). instead, shutdown should only be called when
   * cleanup is necessary (e.g. at exit before leak reporting) and
   * it is certain that the module is no longer in use.
   **/
  LIB_API Status ModuleShutdown(volatile ModuleInitState* initState, void (*shutdown)());
  
  #endif	// #ifndef INCLUDED_MODULE_INIT
  