====== C - C++ Asynchronous function call ======

===== futuresample.hpp =====

<code cpp>
#pragma once

#include <string>

// Call a function in another thread, using a std::future.
std::wstring use_future(std::string filename);
</code>

----

===== future_sample.cpp =====

<code cpp>
#include "futuresample.hpp"
#include <sstream>
#include <fstream>
#include <future>

class SampleReadClass
{
public:
  static std::wstring staticfunction_read(std::string filename)
  {
    std::wostringstream stream;
    stream << std::wifstream(filename).rdbuf();
    return stream.str();
  }

  
  std::wstring memberfunction_read(std::string filename)
  {
    return staticfunction_read(filename);
  }
};


std::wstring use_future(std::string filename)
{
  // Sample 1.
  std::future<std::wstring> f1 = std::async(SampleReadClass::staticfunction_read, filename);


  // Sample 2.
  SampleReadClass sampleReadClass;
  std::future<std::wstring> f2 = std::async([&]
  {
    return sampleReadClass.memberfunction_read(filename);
  });

  
  //
  // Do other things here...
  //

  return f1.get() + f2.get();
}
</code>

----

===== References =====

https://en.cppreference.com/w/cpp/thread/future