C / C++ / MFC

HANDLE P1 = create_a_named_pipe("Bob");

While (TRUE)
{
  HANDLE P2 = create_a_named_pipe("Bob"); // A "pipe in waiting"

  wait_for_a_connection(P1);
  
  // at this point, you can process the messages being passed on P1.  You can either do it in
  // this code or if you are communicating with "unsynchronized" clients, you might want to
  // create a thread to work on P1.  If you do that, make sure then make their own copy of
  // P1 because we are about to clobber it.

  // once you are done processing the communication, close the P1 handle, here or in the thread

  P1 = P2;  // switch to the waiting pipe
}

#include "classref.h" // file header of  the application using the DLL 
extern "C" __declspec(dllexport) int MainEntry( ClassRef* pRef )
{ 
     // entier is a public attribute of the application that uses the DLL
     int XX = pRef->entier; // This works

 
    //getval is a public member function of the application that uses the DLL
    XX = pRef->setval(5); // compile but does not build. unresolved external symbol errors
 
  return 0;
}

void setval( int val)
{
     double dbl = m_ref->unDouble(16.45);// This is a member function of another class of the application
     entier = val * dbl ;
}