tbb_main.h

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/*
    Copyright (c) 2005-2020 Intel Corporation

    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.
    You may obtain a copy of the License at

        http://www.apache.org/licenses/LICENSE-2.0

    Unless required by applicable law or agreed to in writing, software
    distributed under the License is distributed on an "AS IS" BASIS,
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.
*/

#ifndef _TBB_tbb_main_H
#define _TBB_tbb_main_H

#include "tbb/atomic.h"
#include "governor.h"
#include "tbb_environment.h"

namespace tbb {

namespace internal {

void DoOneTimeInitializations ();

//------------------------------------------------------------------------
// __TBB_InitOnce
//------------------------------------------------------------------------


class __TBB_InitOnce {
    friend void DoOneTimeInitializations();
    friend void ITT_DoUnsafeOneTimeInitialization ();

    static atomic<int> count;

    static void acquire_resources();

    static void release_resources();

    static bool InitializationDone;


    static __TBB_atomic_flag InitializationLock;

public:
    static void lock()   { __TBB_LockByte( InitializationLock ); }

    static void unlock() { __TBB_UnlockByte( InitializationLock ); }

    static bool initialization_done() { return __TBB_load_with_acquire(InitializationDone); }


    __TBB_InitOnce() { add_ref(); }


    ~__TBB_InitOnce() {
        governor::terminate_auto_initialized_scheduler(); // TLS dtor not called for the main thread
        remove_ref();
        // We assume that InitializationDone is not set after file-scope destructors
        // start running, and thus no race on InitializationDone is possible.
        if( initialization_done() ) {
            // Remove an extra reference that was added in DoOneTimeInitializations.
            remove_ref();
        }
    }
    static void add_ref();

    static void remove_ref();
}; // class __TBB_InitOnce


} // namespace internal

} // namespace tbb

#endif /* _TBB_tbb_main_H */