task_scheduler_init.h

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/*
    Copyright (c) 2005-2019 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_task_scheduler_init_H
#define __TBB_task_scheduler_init_H

#include "tbb_stddef.h"
#include "limits.h"
#if __TBB_SUPPORTS_WORKERS_WAITING_IN_TERMINATE
#include <new> // nothrow_t
#endif

namespace tbb {

typedef std::size_t stack_size_type;

namespace internal {

    class scheduler;
} // namespace internal


class task_scheduler_init: internal::no_copy {
    enum ExceptionPropagationMode {
        propagation_mode_exact = 1u,
        propagation_mode_captured = 2u,
        propagation_mode_mask = propagation_mode_exact | propagation_mode_captured
    };

    internal::scheduler* my_scheduler;

    bool internal_terminate( bool blocking );
#if __TBB_SUPPORTS_WORKERS_WAITING_IN_TERMINATE
    bool __TBB_EXPORTED_METHOD internal_blocking_terminate( bool throwing );
#endif
public:

    static const int automatic = -1;

    static const int deferred = -2;


    void __TBB_EXPORTED_METHOD initialize( int number_of_threads=automatic );


    void __TBB_EXPORTED_METHOD initialize( int number_of_threads, stack_size_type thread_stack_size );

    void __TBB_EXPORTED_METHOD terminate();

#if __TBB_SUPPORTS_WORKERS_WAITING_IN_TERMINATE
#if TBB_USE_EXCEPTIONS
    void blocking_terminate() {
        internal_blocking_terminate( /*throwing=*/true );
    }
#endif
    bool blocking_terminate(const std::nothrow_t&) __TBB_NOEXCEPT(true) {
        return internal_blocking_terminate( /*throwing=*/false );
    }
#endif // __TBB_SUPPORTS_WORKERS_WAITING_IN_TERMINATE

    task_scheduler_init( int number_of_threads=automatic, stack_size_type thread_stack_size=0 ) : my_scheduler(NULL)
    {
        // Two lowest order bits of the stack size argument may be taken to communicate
        // default exception propagation mode of the client to be used when the
        // client manually creates tasks in the master thread and does not use
        // explicit task group context object. This is necessary because newer
        // TBB binaries with exact propagation enabled by default may be used
        // by older clients that expect tbb::captured_exception wrapper.
        // All zeros mean old client - no preference.
        __TBB_ASSERT( !(thread_stack_size & propagation_mode_mask), "Requested stack size is not aligned" );
#if TBB_USE_EXCEPTIONS
        thread_stack_size |= TBB_USE_CAPTURED_EXCEPTION ? propagation_mode_captured : propagation_mode_exact;
#endif /* TBB_USE_EXCEPTIONS */
        initialize( number_of_threads, thread_stack_size );
    }

    ~task_scheduler_init() {
        if( my_scheduler )
            terminate();
        internal::poison_pointer( my_scheduler );
    }

    static int __TBB_EXPORTED_FUNC default_num_threads ();

    bool is_active() const { return my_scheduler != NULL; }
};

} // namespace tbb

#endif /* __TBB_task_scheduler_init_H */