c++ - 使用 void 函数作为回调，从 "std::function<void ()>?

Question

我有一个使用回调的基于 boost::Asio 的串口阅读器，如下所示:

void received(const char *data, unsigned int len)
{

        string s(data, len);
        cout <<  s  << endl;    

}

int main()
{

    try {
        CallbackAsyncSerial serial("COM4", 115200);
        serial.setCallback(received);
        for(;;)
        {
            if(serial.errorStatus() || serial.isOpen()==false)
            {
                cerr<<"Error: serial port unexpectedly closed"<<endl;
                break;
            }
            char c;
            cin.get(c); //blocking wait for standard input
           serial.write(&c,1);
        }
        quit:
        serial.close();
    } catch (std::exception& e) {
        cerr<<"Exception: "<<e.what()<<endl;
    }

}

如上所述，编译并运行。现在我需要将它合并到一个现有的类中，所以我有:

void MyClass::received(const char *data, unsigned int len)
{

        string s(data, len);
        cout <<  s  << endl;    

}

int MyClass::main()
{

    try {
        CallbackAsyncSerial serial("COM4", 115200);
        serial.setCallback(received); //COMPILE ERROR HERE
        for(;;)
        {
            if(serial.errorStatus() || serial.isOpen()==false)
            {
                cerr<<"Error: serial port unexpectedly closed"<<endl;
                break;
            }
            char c;
            cin.get(c); //blocking wait for standard input
           serial.write(&c,1);
        }
        quit:
        serial.close();
    } catch (std::exception& e) {
        cerr<<"Exception: "<<e.what()<<endl;
    }

}

但是，添加 MyClass::received停止编译，给我:

Error (active)  E0415   no suitable constructor exists to convert from "void (const char *data, unsigned int len)" to "std::function<void (const char *, size_t)>"

我尝试将其调整为:

std::function< void() >received(const char *data, unsigned int len);

但我看到了同样的事情。 我需要在这里做什么？

Answer 1

由 rafix07 在评论中回答

我需要的是将 setCallback 行调整为:

serial.setCallback(
    std::bind(&MyClass::received, this, std::placeholders::_1, std::placeholders::_2));