• 1.1 基于原版sigslot做了部分修改。原版的信号支持最多支持8个参数，改进后，最多支持1个参数，这样肯定不能满足日常需求，但是，我们可以将信号的一个参数改为类型指针，比如信号定义时的模板传递一个结构体，这样，就可以很方便的传递多于1个的参数了，将参数做了封装放入到结构体，槽函数直接读取传过来的结构体内容。 很方便的对其做了扩展。

  简单说： 去冗余代码。

• 1.2 改进版中增加了部分注释

  一份良好的代码需要良好的注释。可能是我水平太低，哈哈，习惯了。

• 1.3 仅仅去除了冗余代码，并没有改变其用法，之前怎么用的，现在还是怎么用。

源码

//
// Written by Sarah Thompson (sarah@telergy.com) 2002.
//
// License: Public domain. You are free to use this code however you like, with the proviso that
//          the author takes on no responsibility or liability for any use.
//
// QUICK DOCUMENTATION
//
//              (see also the full documentation at http://sigslot.sourceforge.net/)
//
//      #define switches
//          SIGSLOT_PURE_ISO            - Define this to force ISO C++ compliance. This also disables
//                                        all of the thread safety support on platforms where it is
//                                        available.
//
//          SIGSLOT_USE_POSIX_THREADS   - Force use of Posix threads when using a C++ compiler other than
//                                        gcc on a platform that supports Posix threads. (When using gcc,
//                                        this is the default - use SIGSLOT_PURE_ISO to disable this if
//                                        necessary)
//
//          SIGSLOT_DEFAULT_MT_POLICY   - Where thread support is enabled, this defaults to multi_threaded_global.
//                                        Otherwise, the default is single_threaded. #define this yourself to
//                                        override the default. In pure ISO mode, anything other than
//                                        single_threaded will cause a compiler error.
//
//      PLATFORM NOTES
//
//          Win32                       - On Win32, the WIN32 symbol must be #defined. Most mainstream
//                                        compilers do this by default, but you may need to define it
//                                        yourself if your build environment is less standard. This causes
//                                        the Win32 thread support to be compiled in and used automatically.
//
//          Unix/Linux/BSD, etc.        - If you're using gcc, it is assumed that you have Posix threads
//                                        available, so they are used automatically. You can override this
//                                        (as under Windows) with the SIGSLOT_PURE_ISO switch. If you're using
//                                        something other than gcc but still want to use Posix threads, you
//                                        need to #define SIGSLOT_USE_POSIX_THREADS.
//
//          ISO C++                     - If none of the supported platforms are detected, or if
//                                        SIGSLOT_PURE_ISO is defined, all multithreading support is turned off,
//                                        along with any code that might cause a pure ISO C++ environment to
//                                        complain. Before you ask, gcc -ansi -pedantic won't compile this
//                                        library, but gcc -ansi is fine. Pedantic mode seems to throw a lot of
//                                        errors that aren't really there. If you feel like investigating this,
//                                        please contact the author.
//
//
//      THREADING MODES
//
//          single_threaded             - Your program is assumed to be single threaded from the point of view
//                                        of signal/slot usage (i.e. all objects using signals and slots are
//                                        created and destroyed from a single thread). Behaviour if objects are
//                                        destroyed concurrently is undefined (i.e. you'll get the occasional
//                                        segmentation fault/memory exception).
//
//          multi_threaded_global       - Your program is assumed to be multi threaded. Objects using signals and
//                                        slots can be safely created and destroyed from any thread, even when
//                                        connections exist. In multi_threaded_global mode, this is achieved by a
//                                        single global mutex (actually a critical section on Windows because they
//                                        are faster). This option uses less OS resources, but results in more
//                                        opportunities for contention, possibly resulting in more context switches
//                                        than are strictly necessary.
//
//          multi_threaded_local        - Behaviour in this mode is essentially the same as multi_threaded_global,
//                                        except that each signal, and each object that inherits has_slots, all
//                                        have their own mutex/critical section. In practice, this means that
//                                        mutex collisions (and hence context switches) only happen if they are
//                                        absolutely essential. However, on some platforms, creating a lot of
//                                        mutexes can slow down the whole OS, so use this option with care.
//
//      USING THE LIBRARY
//
//          See the full documentation at http://sigslot.sourceforge.net/
//
//
// Libjingle specific:
// This file has been modified such that has_slots and signalx do not have to be
// using the same threading requirements. E.g. it is possible to connect a
// has_slots<single_threaded> and signal0<multi_threaded_local> or
// has_slots<multi_threaded_local> and signal0<single_threaded>.
// If has_slots is single threaded the user must ensure that it is not trying
// to connect or disconnect to signalx concurrently or data race may occur.
// If signalx is single threaded the user must ensure that disconnect, connect
// or signal is not happening concurrently or data race may occur.

#ifndef _SIGSLOT_H__
#define _SIGSLOT_H__

#include <list>
#include <set>
#include <stdlib.h>

// On our copy of sigslot.h, we set single threading as default.
#define SIGSLOT_DEFAULT_MT_POLICY single_threaded

// 强制设定其为ISO C++编译器，并关闭所有的操作系统提供的线程安全的支持。
#if defined(SIGSLOT_PURE_ISO) || (!defined(WIN32) && !defined(__GNUG__) && !defined(SIGSLOT_USE_POSIX_THREADS))
#   define _SIGSLOT_SINGLE_THREADED
#elif defined(WIN32)
#   define _SIGSLOT_HAS_WIN32_THREADS
#   if !defined(WIN32_LEAN_AND_MEAN)
#       define WIN32_LEAN_AND_MEAN
#   endif
#   include <windows.h>

// 当使用gcc以外的编译器，而编译器支持Posix线程时，强制使用Posix线程支持。
#elif defined(__GNUG__) || defined(SIGSLOT_USE_POSIX_THREADS)
#   define _SIGSLOT_HAS_POSIX_THREADS
#   include <pthread.h>
#else
#   define _SIGSLOT_SINGLE_THREADED
#endif

//  当启用多线程支持时，默认项为全局多线程(multi_threaded_global)。否则默认项为单线程
#ifndef SIGSLOT_DEFAULT_MT_POLICY
#   ifdef _SIGSLOT_SINGLE_THREADED
#       define SIGSLOT_DEFAULT_MT_POLICY single_threaded
#   else
#       define SIGSLOT_DEFAULT_MT_POLICY multi_threaded_local
#   endif
#endif

// TODO: change this namespace to talk_base?
namespace sigslot
{

    class single_threaded
    {
    public:
        single_threaded()
        {
            ;
        }

        virtual ~single_threaded()
        {
            ;
        }

        virtual void lock()
        {
            ;
        }

        virtual void unlock()
        {
            ;
        }
    };

#ifdef _SIGSLOT_HAS_WIN32_THREADS
    // The multi threading policies only get compiled in if they are enabled.
    class multi_threaded_global
    {
    public:
        multi_threaded_global()
        {
            static bool isinitialised = false;

            if (!isinitialised)
            {
                InitializeCriticalSection(get_critsec());
                isinitialised = true;
            }
        }

        multi_threaded_global(const multi_threaded_global&)
        {
            ;
        }

        virtual ~multi_threaded_global()
        {
            ;
        }

        virtual void lock()
        {
            EnterCriticalSection(get_critsec());
        }

        virtual void unlock()
        {
            LeaveCriticalSection(get_critsec());
        }

    private:
        CRITICAL_SECTION* get_critsec()
        {
            static CRITICAL_SECTION g_critsec;
            return &g_critsec;
        }
    };

    class multi_threaded_local
    {
    public:
        multi_threaded_local()
        {
            InitializeCriticalSection(&m_critsec);
        }

        multi_threaded_local(const multi_threaded_local&)
        {
            InitializeCriticalSection(&m_critsec);
        }

        virtual ~multi_threaded_local()
        {
            DeleteCriticalSection(&m_critsec);
        }

        virtual void lock()
        {
            EnterCriticalSection(&m_critsec);
        }

        virtual void unlock()
        {
            LeaveCriticalSection(&m_critsec);
        }

    private:
        CRITICAL_SECTION m_critsec;
    };
#endif // _SIGSLOT_HAS_WIN32_THREADS

#ifdef _SIGSLOT_HAS_POSIX_THREADS
    // The multi threading policies only get compiled in if they are enabled.
    class multi_threaded_global
    {
    public:
        multi_threaded_global()
        {
            pthread_mutex_init(get_mutex(), NULL);
        }

        multi_threaded_global(const multi_threaded_global&)
        {
            ;
        }

        virtual ~multi_threaded_global()
        {
            ;
        }

        virtual void lock()
        {
            pthread_mutex_lock(get_mutex());
        }

        virtual void unlock()
        {
            pthread_mutex_unlock(get_mutex());
        }

    private:
        pthread_mutex_t* get_mutex()
        {
            static pthread_mutex_t g_mutex;
            return &g_mutex;
        }
    };

    class multi_threaded_local
    {
    public:
        multi_threaded_local()
        {
            pthread_mutex_init(&m_mutex, NULL);
        }

        multi_threaded_local(const multi_threaded_local&)
        {
            pthread_mutex_init(&m_mutex, NULL);
        }

        virtual ~multi_threaded_local()
        {
            pthread_mutex_destroy(&m_mutex);
        }

        virtual void lock()
        {
            pthread_mutex_lock(&m_mutex);
        }

        virtual void unlock()
        {
            pthread_mutex_unlock(&m_mutex);
        }

    private:
        pthread_mutex_t m_mutex;
    };
#endif // _SIGSLOT_HAS_POSIX_THREADS

    /**
    * @brief: 锁对象：
            lock_block模板类，最终根据实例化的模板类使用相应的线程模型和同步对象，
            只需要将该类实例化到需要的位置即实现了线程同步功能，这是比较规范并简单有效的方法。
            mt_policy被指定为SIGSLOT_DEFAULT_MT_POLICY宏，同时也作为一个强制指定为单线程模型的开关。
    */
    template<class mt_policy>
    class lock_block
    {
    public:
        mt_policy *m_mutex;

        lock_block(mt_policy *mtx)
            : m_mutex(mtx)
        {
            m_mutex->lock();
        }

        ~lock_block()
        {
            m_mutex->unlock();
        }
    };

//----------------------------------------------------------------------------------------

    class has_slots_interface;
    /**
    * @brief: 连接对象接口类
    */
    template<class mt_policy>
    class _connection_base0
    {
    public:
        virtual ~_connection_base0() {}
        virtual has_slots_interface* getdest() const = 0;
        virtual void emit() = 0;
        virtual _connection_base0* clone() = 0;
        virtual _connection_base0* duplicate(has_slots_interface* pnewdest) = 0;
    };

    /**
    * @brief: 连接对象 _connection0 ... _connection8
            _connection0<dest_type,mt_policy>...
            _connection8<dest_type,arg1_type...arg8_type,mt_policy>
            是接口:
            _connection_base0<mt_policy> ...
            _connection_base8<arg1_type,...arg8_type,mt_policy>的实现类，其中：

            clone():
            使用默认拷贝构造函数返回一个新的_connection_baseN对象指针。

            duplicate(sigslot::has_slots<mt_policy> *pnewdest):
            返回一个新的目标对象为pnewdest的_connection_baseN对象指针。

            emit(arg0_type a0..argN_type aN):
            触发_connection_baseN中目标对象中指定的函数指针。

            getdest(void)const:
            返回目标对象指针。
    */
    template<class arg1_type, class mt_policy>
    class _connection_base1
    {
    public:
        virtual ~_connection_base1() {}
        virtual has_slots_interface* getdest() const = 0;
        virtual void emit(arg1_type) = 0;
        virtual _connection_base1<arg1_type, mt_policy>* clone() = 0;
        virtual _connection_base1<arg1_type, mt_policy>* duplicate(has_slots_interface* pnewdest) = 0;
    };

//--------------------------------------------------------------------------------------------------------------

    /**
    * @brief: 信号接口
    */
    class _signal_base_interface
    {
    public:
        virtual void slot_disconnect(has_slots_interface* pslot) = 0;
        virtual void slot_duplicate(const has_slots_interface* poldslot, has_slots_interface* pnewslot) = 0;
    };

    /**
    * @brief: 扩展信号接口类
    */
    template<class mt_policy>
    class _signal_base : public _signal_base_interface, public mt_policy
    {
    };

    /**
    * @brief:信号槽接口类，
    */
    class has_slots_interface
    {
    public:
        has_slots_interface()
        {
            ;
        }

        virtual void signal_connect(_signal_base_interface* sender) = 0;

        virtual void signal_disconnect(_signal_base_interface* sender) = 0;

        virtual ~has_slots_interface()
        {
        }

        virtual void disconnect_all() = 0;
    };

    /**
    * @brief: 扩展信号槽接口
    */
    template<class mt_policy = SIGSLOT_DEFAULT_MT_POLICY>
    class has_slots : public has_slots_interface, public mt_policy
    {
    private:
        typedef std::set<_signal_base_interface*> sender_set;
        typedef sender_set::const_iterator const_iterator;

    public:
        has_slots()
        {
            ;
        }

        has_slots(const has_slots& hs)
        {
            lock_block<mt_policy> lock(this);
            const_iterator it = hs.m_senders.begin();
            const_iterator itEnd = hs.m_senders.end();

            while (it != itEnd)
            {
                (*it)->slot_duplicate(&hs, this);
                m_senders.insert(*it);
                ++it;
            }
        }

        void signal_connect(_signal_base_interface* sender)
        {
            lock_block<mt_policy> lock(this);
            m_senders.insert(sender);
        }

        void signal_disconnect(_signal_base_interface* sender)
        {
            lock_block<mt_policy> lock(this);
            m_senders.erase(sender);
        }

        virtual ~has_slots()
        {
            disconnect_all();
        }

        void disconnect_all()
        {
            lock_block<mt_policy> lock(this);
            const_iterator it = m_senders.begin();
            const_iterator itEnd = m_senders.end();

            while (it != itEnd)
            {
                (*it)->slot_disconnect(this);
                ++it;
            }

            m_senders.erase(m_senders.begin(), m_senders.end());
        }

    private:
        sender_set m_senders;
    };

    /**
    * @brief: 信号对象
    */
    template<class mt_policy>
    class _signal_base0 : public _signal_base<mt_policy>
    {
    public:
        typedef std::list<_connection_base0<mt_policy> *>  connections_list;

        _signal_base0()
        {
            ;
        }

        _signal_base0(const _signal_base0& s)
            : _signal_base<mt_policy>(s)
        {
            lock_block<mt_policy> lock(this);
            typename connections_list::const_iterator it = s.m_connected_slots.begin();
            typename connections_list::const_iterator itEnd = s.m_connected_slots.end();

            while (it != itEnd)
            {
                (*it)->getdest()->signal_connect(this);
                m_connected_slots.push_back((*it)->clone());

                ++it;
            }
        }

        ~_signal_base0()
        {
            disconnect_all();
        }

        bool is_empty()
        {
            lock_block<mt_policy> lock(this);
            typename connections_list::const_iterator it = m_connected_slots.begin();
            typename connections_list::const_iterator itEnd = m_connected_slots.end();
            return it == itEnd;
        }

        void disconnect_all()
        {
            lock_block<mt_policy> lock(this);
            typename connections_list::const_iterator it = m_connected_slots.begin();
            typename connections_list::const_iterator itEnd = m_connected_slots.end();

            while (it != itEnd)
            {
                (*it)->getdest()->signal_disconnect(this);
                delete *it;

                ++it;
            }

            m_connected_slots.erase(m_connected_slots.begin(), m_connected_slots.end());
        }

#ifdef _DEBUG
        bool connected(has_slots_interface* pclass)
        {
            lock_block<mt_policy> lock(this);
            typename connections_list::const_iterator itNext, it = m_connected_slots.begin();
            typename connections_list::const_iterator itEnd = m_connected_slots.end();
            while (it != itEnd)
            {
                itNext = it;
                ++itNext;
                if ((*it)->getdest() == pclass)
                    return true;
                it = itNext;
            }
            return false;
        }
#endif

        void disconnect(has_slots_interface* pclass)
        {
            lock_block<mt_policy> lock(this);
            typename connections_list::iterator it = m_connected_slots.begin();
            typename connections_list::iterator itEnd = m_connected_slots.end();

            while (it != itEnd)
            {
                if ((*it)->getdest() == pclass)
                {
                    delete *it;
                    m_connected_slots.erase(it);
                    pclass->signal_disconnect(this);
                    return;
                }

                ++it;
            }
        }

        void slot_disconnect(has_slots_interface* pslot)
        {
            lock_block<mt_policy> lock(this);
            typename connections_list::iterator it = m_connected_slots.begin();
            typename connections_list::iterator itEnd = m_connected_slots.end();

            while (it != itEnd)
            {
                typename connections_list::iterator itNext = it;
                ++itNext;

                if ((*it)->getdest() == pslot)
                {
                    delete *it;
                    m_connected_slots.erase(it);
                }

                it = itNext;
            }
        }

        void slot_duplicate(const has_slots_interface* oldtarget, has_slots_interface* newtarget)
        {
            lock_block<mt_policy> lock(this);
            typename connections_list::iterator it = m_connected_slots.begin();
            typename connections_list::iterator itEnd = m_connected_slots.end();

            while (it != itEnd)
            {
                if ((*it)->getdest() == oldtarget)
                {
                    m_connected_slots.push_back((*it)->duplicate(newtarget));
                }

                ++it;
            }
        }

    protected:
        connections_list m_connected_slots;
    };

    /**
    * @brief:   信号对象 Signal0 ... Signal8

                以带一个参数的信号对象为例：signal1<arg1_type,mt_policy>的emit(arg1_type a1)
                与 重载运算符operator ()(arg1_type a1)功能是一致的。
                都是遍历父类成员m_connected_slots中的_connection_base1<arg1_type,
                mt_policy>指针元素，逐一的调用_connection_base1中的emit(a1)函数最终使目标函数被调用。

                函数connect（）生成模板参数的目标对象和目标函数指针，并将该新连接加入到已连接的列表m_connected_slots中。
                最后使用has_slots的signal_connect函数，将signal1信号对象加入到has_slots的m_senders列表中
    */
    template<class arg1_type, class mt_policy>
    class _signal_base1 : public _signal_base<mt_policy>
    {
    public:
        typedef std::list<_connection_base1<arg1_type, mt_policy> *>  connections_list;

        _signal_base1()
        {
            ;
        }

        _signal_base1(const _signal_base1<arg1_type, mt_policy>& s)
            : _signal_base<mt_policy>(s)
        {
            lock_block<mt_policy> lock(this);
            typename connections_list::const_iterator it = s.m_connected_slots.begin();
            typename connections_list::const_iterator itEnd = s.m_connected_slots.end();

            while (it != itEnd)
            {
                (*it)->getdest()->signal_connect(this);
                m_connected_slots.push_back((*it)->clone());

                ++it;
            }
        }

        void slot_duplicate(const has_slots_interface* oldtarget, has_slots_interface* newtarget)
        {
            lock_block<mt_policy> lock(this);
            typename connections_list::iterator it = m_connected_slots.begin();
            typename connections_list::iterator itEnd = m_connected_slots.end();

            while (it != itEnd)
            {
                if ((*it)->getdest() == oldtarget)
                {
                    m_connected_slots.push_back((*it)->duplicate(newtarget));
                }

                ++it;
            }
        }

        ~_signal_base1()
        {
            disconnect_all();
        }

        bool is_empty()
        {
            lock_block<mt_policy> lock(this);
            typename connections_list::const_iterator it = m_connected_slots.begin();
            typename connections_list::const_iterator itEnd = m_connected_slots.end();
            return it == itEnd;
        }

        void disconnect_all()
        {
            lock_block<mt_policy> lock(this);
            typename connections_list::const_iterator it = m_connected_slots.begin();
            typename connections_list::const_iterator itEnd = m_connected_slots.end();

            while (it != itEnd)
            {
                (*it)->getdest()->signal_disconnect(this);
                delete *it;

                ++it;
            }

            m_connected_slots.erase(m_connected_slots.begin(), m_connected_slots.end());
        }

#ifdef _DEBUG
        bool connected(has_slots_interface* pclass)
        {
            lock_block<mt_policy> lock(this);
            typename connections_list::const_iterator itNext, it = m_connected_slots.begin();
            typename connections_list::const_iterator itEnd = m_connected_slots.end();
            while (it != itEnd)
            {
                itNext = it;
                ++itNext;
                if ((*it)->getdest() == pclass)
                    return true;
                it = itNext;
            }
            return false;
        }
#endif

        void disconnect(has_slots_interface* pclass)
        {
            lock_block<mt_policy> lock(this);
            typename connections_list::iterator it = m_connected_slots.begin();
            typename connections_list::iterator itEnd = m_connected_slots.end();

            while (it != itEnd)
            {
                if ((*it)->getdest() == pclass)
                {
                    delete *it;
                    m_connected_slots.erase(it);
                    pclass->signal_disconnect(this);
                    return;
                }

                ++it;
            }
        }

        void slot_disconnect(has_slots_interface* pslot)
        {
            lock_block<mt_policy> lock(this);
            typename connections_list::iterator it = m_connected_slots.begin();
            typename connections_list::iterator itEnd = m_connected_slots.end();

            while (it != itEnd)
            {
                typename connections_list::iterator itNext = it;
                ++itNext;

                if ((*it)->getdest() == pslot)
                {
                    delete *it;
                    m_connected_slots.erase(it);
                }

                it = itNext;
            }
        }

    protected:
        connections_list m_connected_slots;
    };

    /**
    * @brief:   _connection0 ... _connection8
                _connection0<dest_type,mt_policy>...
                _connection8<dest_type,arg1_type...arg8_type,mt_policy>
                是接口:
                _connection_base0<mt_policy> ...
                _connection_base8<arg1_type,...arg8_type,mt_policy>的实现类，其中：

                clone():
                使用默认拷贝构造函数返回一个新的_connection_baseN对象指针。

                duplicate(sigslot::has_slots<mt_policy> *pnewdest):
                返回一个新的目标对象为pnewdest的_connection_baseN对象指针。

                emit(arg0_type a0..argN_type aN):
                触发_connection_baseN中目标对象中指定的函数指针。

                getdest(void)const:
                返回目标对象指针。
    */
    template<class dest_type, class mt_policy>
    class _connection0 : public _connection_base0<mt_policy>
    {
    public:
        _connection0()
        {
            m_pobject = NULL;
            m_pmemfun = NULL;
        }

        _connection0(dest_type* pobject, void (dest_type::*pmemfun)())
        {
            m_pobject = pobject;
            m_pmemfun = pmemfun;
        }

        virtual ~_connection0()
        {
        }

        virtual _connection_base0<mt_policy>* clone()
        {
            return new _connection0<dest_type, mt_policy>(*this);
        }

        virtual _connection_base0<mt_policy>* duplicate(has_slots_interface* pnewdest)
        {
            return new _connection0<dest_type, mt_policy>((dest_type *)pnewdest, m_pmemfun);
        }

        virtual void emit()
        {
            (m_pobject->*m_pmemfun)();
        }

        virtual has_slots_interface* getdest() const
        {
            return m_pobject;
        }

    private:
        dest_type* m_pobject;
        void (dest_type::* m_pmemfun)();
    };

    /**
    * @brief:    _connection0 ... _connection8
                _connection0<dest_type,mt_policy>...
                _connection8<dest_type,arg1_type...arg8_type,mt_policy>
                是接口:
                _connection_base0<mt_policy> ...
                _connection_base8<arg1_type,...arg8_type,mt_policy>的实现类，其中：

                clone():
                使用默认拷贝构造函数返回一个新的_connection_baseN对象指针。

                duplicate(sigslot::has_slots<mt_policy> *pnewdest):
                返回一个新的目标对象为pnewdest的_connection_baseN对象指针。

                emit(arg0_type a0..argN_type aN):
                触发_connection_baseN中目标对象中指定的函数指针。

                getdest(void)const:
                返回目标对象指针。
    */
    template<class dest_type, class arg1_type, class mt_policy>
    class _connection1 : public _connection_base1<arg1_type, mt_policy>
    {
    public:
        _connection1()
        {
            m_pobject = NULL;
            m_pmemfun = NULL;
        }

        _connection1(dest_type* pobject, void (dest_type::*pmemfun)(arg1_type))
        {
            m_pobject = pobject;
            m_pmemfun = pmemfun;
        }

        virtual ~_connection1()
        {
        }

        virtual _connection_base1<arg1_type, mt_policy>* clone()
        {
            return new _connection1<dest_type, arg1_type, mt_policy>(*this);
        }

        virtual _connection_base1<arg1_type, mt_policy>* duplicate(has_slots_interface* pnewdest)
        {
            return new _connection1<dest_type, arg1_type, mt_policy>((dest_type *)pnewdest, m_pmemfun);
        }

        virtual void emit(arg1_type a1)
        {
            (m_pobject->*m_pmemfun)(a1);
        }

        virtual has_slots_interface* getdest() const
        {
            return m_pobject;
        }

    private:
        dest_type* m_pobject;
        void (dest_type::* m_pmemfun)(arg1_type);
    };

    /**
    * @brief: 信号对象
                    以带一个参数的信号对象为例：signal1<arg1_type,mt_policy>的emit(arg1_type a1)
                    与 重载运算符operator ()(arg1_type a1)功能是一致的。
                    都是遍历父类成员m_connected_slots中的_connection_base1<arg1_type, mt_policy>指针元素，
                    逐一的调用_connection_base1中的emit(a1)函数最终使目标函数被调用。

                    函数connect（）生成模板参数的目标对象和目标函数指针，
                    并将该新连接加入到已连接的列表m_connected_slots中。
                    最后使用has_slots的signal_connect函数，将signal1信号对象加入到has_slots的m_senders列表中。
    */
    template<class mt_policy = SIGSLOT_DEFAULT_MT_POLICY>
    class signal0 : public _signal_base0<mt_policy>
    {
    public:
        typedef _signal_base0<mt_policy> base;
        typedef typename base::connections_list connections_list;
        using base::m_connected_slots;

        signal0()
        {
            ;
        }

        signal0(const signal0<mt_policy>& s)
            : _signal_base0<mt_policy>(s)
        {
            ;
        }

        template<class desttype>
        void connect(desttype* pclass, void (desttype::*pmemfun)())
        {
            lock_block<mt_policy> lock(this);
            _connection0<desttype, mt_policy>* conn =
                new _connection0<desttype, mt_policy>(pclass, pmemfun);
            m_connected_slots.push_back(conn);
            pclass->signal_connect(this);
        }

        void emit()
        {
            lock_block<mt_policy> lock(this);
            typename connections_list::const_iterator itNext, it = m_connected_slots.begin();
            typename connections_list::const_iterator itEnd = m_connected_slots.end();

            while (it != itEnd)
            {
                itNext = it;
                ++itNext;

                (*it)->emit();

                it = itNext;
            }
        }

        void operator()()
        {
            lock_block<mt_policy> lock(this);
            typename connections_list::const_iterator itNext, it = m_connected_slots.begin();
            typename connections_list::const_iterator itEnd = m_connected_slots.end();

            while (it != itEnd)
            {
                itNext = it;
                ++itNext;

                (*it)->emit();

                it = itNext;
            }
        }
    };

    /**
    * @brief: 信号对象
                    以带一个参数的信号对象为例：signal1<arg1_type,mt_policy>的emit(arg1_type a1)
                    与 重载运算符operator ()(arg1_type a1)功能是一致的。
                    都是遍历父类成员m_connected_slots中的_connection_base1<arg1_type, mt_policy>指针元素，
                    逐一的调用_connection_base1中的emit(a1)函数最终使目标函数被调用。

                    函数connect（）生成模板参数的目标对象和目标函数指针，
                    并将该新连接加入到已连接的列表m_connected_slots中。
                    最后使用has_slots的signal_connect函数，将signal1信号对象加入到has_slots的m_senders列表中。
    */
    template<class arg1_type, class mt_policy = SIGSLOT_DEFAULT_MT_POLICY>
    class signal1 : public _signal_base1<arg1_type, mt_policy>
    {
    public:
        typedef _signal_base1<arg1_type, mt_policy> base;
        typedef typename base::connections_list connections_list;
        using base::m_connected_slots;

        signal1()
        {
            ;
        }

        signal1(const signal1<arg1_type, mt_policy>& s)
            : _signal_base1<arg1_type, mt_policy>(s)
        {
            ;
        }

        template<class desttype>
        void connect(desttype* pclass, void (desttype::*pmemfun)(arg1_type))
        {
            lock_block<mt_policy> lock(this);
            _connection1<desttype, arg1_type, mt_policy>* conn =
                new _connection1<desttype, arg1_type, mt_policy>(pclass, pmemfun);
            m_connected_slots.push_back(conn);
            pclass->signal_connect(this);
        }

        void emit(arg1_type a1)
        {
            lock_block<mt_policy> lock(this);
            typename connections_list::const_iterator itNext, it = m_connected_slots.begin();
            typename connections_list::const_iterator itEnd = m_connected_slots.end();

            while (it != itEnd)
            {
                itNext = it;
                ++itNext;

                (*it)->emit(a1);

                it = itNext;
            }
        }

        void operator()(arg1_type a1)
        {
            lock_block<mt_policy> lock(this);
            typename connections_list::const_iterator itNext, it = m_connected_slots.begin();
            typename connections_list::const_iterator itEnd = m_connected_slots.end();

            while (it != itEnd)
            {
                itNext = it;
                ++itNext;

                (*it)->emit(a1);

                it = itNext;
            }
        }

    }; // end class

}; // namespace sigslot

#endif // _SIGSLOT_H__s