task_scheduler_init.h

/*
    Copyright 2005-2016 Intel Corporation.  All Rights Reserved.

    This file is part of Threading Building Blocks. Threading Building Blocks is free software;
    you can redistribute it and/or modify it under the terms of the GNU General Public License
    version 2  as  published  by  the  Free Software Foundation.  Threading Building Blocks is
    distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the
    implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
    See  the GNU General Public License for more details.   You should have received a copy of
    the  GNU General Public License along with Threading Building Blocks; if not, write to the
    Free Software Foundation, Inc.,  51 Franklin St,  Fifth Floor,  Boston,  MA 02110-1301 USA

    As a special exception,  you may use this file  as part of a free software library without
    restriction.  Specifically,  if other files instantiate templates  or use macros or inline
    functions from this file, or you compile this file and link it with other files to produce
    an executable,  this file does not by itself cause the resulting executable to be covered
    by the GNU General Public License. This exception does not however invalidate any other
    reasons why the executable file might be covered by the GNU General Public License.
*/

#ifndef __TBB_task_scheduler_init_H
#define __TBB_task_scheduler_init_H

#include "tbb_stddef.h"
#include "limits.h"

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
    };
#if __TBB_SUPPORTS_WORKERS_WAITING_IN_TERMINATE
    enum {
        wait_workers_in_terminate_flag = 128u
    };
#endif

    internal::scheduler* my_scheduler;
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
    task_scheduler_init( int number_of_threads=automatic, stack_size_type thread_stack_size=0, bool wait_workers_in_terminate = false ) : my_scheduler(NULL)
#else
    task_scheduler_init( int number_of_threads=automatic, stack_size_type thread_stack_size=0 ) : my_scheduler(NULL)
#endif
    {
        // 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 */
#if __TBB_SUPPORTS_WORKERS_WAITING_IN_TERMINATE
        if (wait_workers_in_terminate)
            my_scheduler = (internal::scheduler*)wait_workers_in_terminate_flag;
#endif
        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 */