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/* 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
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