Pass std::bind object with bind member function to a function - c++

Question

I want to connect a callback function to a boost signal through a public function. I can pass a function pointer just fine, but if I try to use std::bind to pass a member function, it will not compile. Giving me error saying no viable conversion. What type should I use for the App::SetCallback function argument?
#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-----------------
Reading boost signal documentation more carefully, I learned that I can pass slot type. This solves my problem
#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

Reading boost signal documentation more carefully, I learned that I can pass slot type. This solves my problem
#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;
}