singleton.h

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#ifndef SINGLETON_HPP_
#define SINGLETON_HPP_

#include <boost/utility.hpp>
#include <boost/thread/once.hpp>
#include <boost/scoped_ptr.hpp>

namespace Templates {
        template<class T>
        class Singleton : private boost::noncopyable
        {
        public:
                static T& instance()
                {
                // Initialize object only once.
                        //std::cout<<std::endl<<"singleton instance called"<<std::endl<<std::endl;
                        boost::call_once(initSingleton, flag);
                        // Return reference to object.
                        return *t;
                }
        protected:
                Singleton() {}
                //virtual ~Singleton() {}
                ~Singleton() {}
        private:
                static void initSingleton()
                {
                // Call constructor of the T object.
                        //std::cout<<std::endl<<"singleton init called"<<std::endl<<std::endl;
                        t.reset(new T());
                }
                static boost::scoped_ptr<T> t;
                static boost::once_flag flag;
        };
}
template<class T> boost::scoped_ptr<T> Templates::Singleton<T>::t(0);

template<class T> boost::once_flag Templates::Singleton<T>::flag = BOOST_ONCE_INIT;

#endif /* SINGLETON_HPP_ */