C++ template for Runnable function

Question

I am writing a library for thread management using C++ for my app and as part of the same I am trying to write a template class that takes a FunctionPointer to be executed inside the run function. I am a Java developer and trying to visualize as follows:

class MyRunnable : public Runnable {

    public:
        MyRunnable(fp)
        {
            mFp = fp;
        }

    private:

    FunctionPointer mFp;

    // Will be called by the thread pool using a thread
    void run() 
    {
         mFp();
    }

}

class ThreadManager {

    public:
        void execute(MyRunnable runnable) {
            executeOnAThreadPool(runnable);
        }

}

Since I am not fluent with C++ syntax, I am finding hard to get the constructor defined to take a FunctionPointer as argument with variable number of arguments for the FunctionPointer. Something like:

MyRunnable(Fp fp, Args... args)

Can someone please help me defining the constructor for MyRunnable class above. Thanks.

Answer 1

Not sure... but seems to me that you're looking something as

class MyRunnable
 {
   private:
      std::function<void()> mF;

   public:       
      template <typename F, typename ... Args>
      MyRunnable (F && f, Args && ... args)
       : mF{ [&f, &args...](){ std::forward<F>(f)(std::forward<Args>(args)...); } }
       { }

      void run ()
       { mF(); }
 };

The following is a full compiling example

#include <iostream>
#include <functional>

class MyRunnable
 {
   private:
      std::function<void()> mF;

   public:       
      template <typename F, typename ... Args>
      MyRunnable (F && f, Args && ... args)
       : mF{ [&f, &args...](){ std::forward<F>(f)(std::forward<Args>(args)...); } }
       { }

      void run ()
       { mF(); }
 };

void foo (int a, long b, std::string const & c)
 { std::cout << "executing foo() with " << a << ", " << b << ", " << c << '\n'; }

int main ()
 {
   MyRunnable  mr{foo, 1, 2l, "three"};

   std::cout << "before run" << '\n';

   mr.run();

 }

that prints

before run
executing foo() with 1, 2, three