將具有綁定成員函數的std :: bind對象傳遞給函數

Question

我想通過公共函數將回調函數連接到boost信號。我可以傳遞一個函數指針，但如果我嘗試使用std :: bind來傳遞成員函數，它將不會編譯。給我錯誤說沒有可行的轉換。我應該使用什麼類型的App :: SetCallback函數參數？

#include <functional> 
#include <boost/signal.hpp> 
using namespace std::placeholders; // for _1, _2, _3... 

//plain simple call back function 
void SimpleCallback(int value) { 
//do nothing 
} 
//class contains a boost::signal, set callback through a public function 
class App { 
public: 
    App() : sig_() 
    {} 
    typedef boost::signal<void (int value)> SigType; 
    typedef std::function<void (int value)> CallbackFunType; 
    //connect signal to a callback function 
    void SetCallback(CallbackFunType callback) { 
     sig_.connect(callback); 
    } 
//private: //comment this out for testing purpose. 
    SigType sig_; //this is the boost::signal 
}; 

//class that has member callback function 
class MyCallback { 
public: 
    MyCallback(): 
    val(0), app() 
    {} 
    void MemberCb(int value){ 
     val = value; 
    } 
    void Connect() { 
     auto bind_fun = std::bind(&MyCallback::MemberCb, this, _1); 
     app.SetCallback(bind_fun); //this will not compile, no viable conversion 
     app.sig_.connect(bind_fun); //this is fine 
     app.SetCallback(SimpleCallback); //this is fine 
    } 
private: 
    int val; 
    App app; 
}; 

int main(int argc, char **argv) { 
    MyCallback my_cb; 
    my_cb.Connect(); 
    return 1; 
} 

---------------- UPDATE -----------------

閱讀增壓信號文檔更仔細地，我瞭解到我可以通過插槽類型。這解決了我的問題

#include <functional> 
#include <boost/signal.hpp> 
using namespace std::placeholders; // for _1, _2, _3... 

//plain simple call back function 
void SimpleCallback(int value) { 
//do nothing 
} 
//class contains a boost::signal, set callback through a public function 
class App { 
public: 
    App() : sig_() 
    {} 
    typedef boost::signal<void (int value)> SigType; 
    typedef SigType::slot_type CallbackFunType; 
    //typedef std::function<void (int value)> CallbackFunType; 
    //connect signal to a callback function 
    void SetCallback(CallbackFunType callback) { 
     sig_.connect(callback); 
    } 
//private: //comment this out for testing purpose. 
    SigType sig_; //this is the boost::signal 
}; 

//class that has member callback function 
class MyCallback { 
public: 
    MyCallback(): 
    val(0), app() 
    {} 
    void MemberCb(int value){ 
     val = value; 
    } 
    void Connect() { 
     auto bind_fun = std::bind(&MyCallback::MemberCb, this, _1); 
     app.SetCallback(bind_fun); //using SigType::slot_type 
     app.sig_.connect(bind_fun); 
     app.SetCallback(SimpleCallback); 
    } 
private: 
    int val; 
    App app; 
}; 

int main(int argc, char **argv) { 
    MyCallback my_cb; 
    my_cb.Connect(); 
    return 1; 
} 

Answer 1

更仔細地閱讀升壓信號文檔，我瞭解到我可以通過插槽類型。這解決了我的問題

#include <functional> 
#include <boost/signal.hpp> 
using namespace std::placeholders; // for _1, _2, _3... 

//plain simple call back function 
void SimpleCallback(int value) { 
//do nothing 
} 
//class contains a boost::signal, set callback through a public function 
class App { 
public: 
    App() : sig_() 
    {} 
    typedef boost::signal<void (int value)> SigType; 
    typedef SigType::slot_type CallbackFunType; 
    //typedef std::function<void (int value)> CallbackFunType; 
    //connect signal to a callback function 
    void SetCallback(CallbackFunType callback) { 
     sig_.connect(callback); 
    } 
//private: //comment this out for testing purpose. 
    SigType sig_; //this is the boost::signal 
}; 

//class that has member callback function 
class MyCallback { 
public: 
    MyCallback(): 
    val(0), app() 
    {} 
    void MemberCb(int value){ 
     val = value; 
    } 
    void Connect() { 
     auto bind_fun = std::bind(&MyCallback::MemberCb, this, _1); 
     app.SetCallback(bind_fun); //using SigType::slot_type 
     app.sig_.connect(bind_fun); 
     app.SetCallback(SimpleCallback); 
    } 
private: 
    int val; 
    App app; 
}; 

int main(int argc, char **argv) { 
    MyCallback my_cb; 
    my_cb.Connect(); 
    return 1; 
}