member function pointers with special function

mfp_specialfn.cpp

#include <iostream>
#include <pthread.h>

/** Member function pointers given function name */

// class Launcher exists as a container of an instance and an argument.
// Using templates allows us to use the Launcher for a member of any class

template <class T>
class Launcher {
public:
  Launcher(T* _o, void* _arg) : o(_o), arg(_arg) {}
  void* launch() { return (o->threadMe)(arg); }
  T* o;
  void* arg;
};

// a function with happily external linkage, which we will pass to
// pthread_create instead of the (internal) member function
template <class T>
void* LaunchMember(void* o) {
    Launcher<T>* l = reinterpret_cast<Launcher<T>* >(o);
    return l->launch();
}

class Bar {
public:
  Bar() : i(0) {}
  int i;
};

class Foo {
public:
  Foo();
  void* threadMe(void* arg);
private:
  pthread_t fThread;
  Bar bar;
};


Foo::Foo() {
  bar.i = 42;
  int arg = 12;
  Launcher<Foo> l(this, (void*)&arg);
  pthread_create(&fThread, NULL, LaunchMember<Foo>, &l);
  pthread_join(fThread, NULL);
}

void* Foo::threadMe(void* arg) {
  std::cout << "Foo::threadMe: *arg = " << *((int*)(arg)) << std::endl;
  std::cout << "Foo::threadMe: bar.i = " << bar.i << std::endl;
}

int main(int argc, char* argv[]) {
  Foo* f = new Foo();
  return 0;
}