MeyerSingleton.hpp

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/*

  This file is part of OpenFLUID software
  Copyright(c) 2007, INRA - Montpellier SupAgro


 == GNU General Public License Usage ==

  OpenFLUID is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.

  OpenFLUID 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 OpenFLUID. If not, see <http://www.gnu.org/licenses/>.


 == Other Usage ==

  Other Usage means a use of OpenFLUID that is inconsistent with the GPL
  license, and requires a written agreement between You and INRA.
  Licensees for Other Usage of OpenFLUID may use this file in accordance
  with the terms contained in the written agreement between You and INRA.
  
*/

/**
  @file MeyerSingleton.hpp

  @author Jean-Christophe FABRE <jean-christophe.fabre@inra.fr>
*/


#ifndef __OPENFLUID_UTILS_MEYERSINGLETON_HPP__
#define __OPENFLUID_UTILS_MEYERSINGLETON_HPP__


namespace openfluid { namespace utils {


/**
  Singleton template class implementing the Meyer's singleton design.
  This implementation is thread safe in C++11.

  @warning This template class does not work in a cross-dll context on Windows.
  Due to this restriction, it must not be used in the OpenFLUID framework.

  Example of use to design an Example class as a singleton
  @code
class Example : public openfluid::utils::MeyerSingleton<Example>
{
  friend class openfluid::utils::MeyerSingleton<Example>;


  private:

    Example();

    ~Example();


  public:

    // some public members
};
  @endcode
*/
template<typename T>
class MeyerSingleton
{

  private:

    MeyerSingleton<T>(T const&) = delete;

    void operator=(T const&) = delete;


  protected:

    MeyerSingleton<T>() = default;


  public:


    /**
      Returns a pointer to the singleton object.
      Instantiates the class if it not has not been instantiated before.
      @return A pointer to the singleton object
    */
    static T* instance()
    {
       static T m_Instance;
       return &m_Instance;
    }
};


} }  // namespaces


#endif /* __OPENFLUID_UTILS_MEYERSINGLETON_HPP__ */