C / C++ / MFC

1. An abstract class defining the functions a plugin has to implement (important: define the destructor as virtual.)
2. A common "creation point" all DLLs are supposed to provide accessed with GetProcAddress, just like this:

   typedef CPluginInterface * (WINAPI * PLUGIN_CREATOR)();
   ...
   PLUGIN_CREATOR * plugin_creator=(PLUGIN_CREATOR *)GetProcAddress(hPluginDll,"Creator");
   CPluginInterface *plugin=plugin_creator();
   ... // use the plugin
   delete plugin;

   Internally, creator functions just create plugins with new.

GetSystemMetrics()

EnumDisplayMonitors()
GetMonitorInfo()
MonitorFormPoint()
MonitorFromRect()
MonitorFromWindow()

//globals
//Holds monitor top-left coordinates within vSpace???
int monView[9][2]; /* Window 98 allows 9 montors max */
int nMonitors = 0;  /* Number of current monitors */

BOOL CALLBACK MonInfo(HMONITOR hMon, HDC hdc, LPRECT rect, LPARAM extra){
  MONITORINFOEX mi;

  mi.cbSize = sizeof(MONITORINFOEX);
  GetMonitorInfo(hMon, &mi); 
  monView[nMonitors][0] = mi.rcMonitor.left;
  monView[nMonitors][1] = mi.rcMonitor.top;
  nMonitors++;

  return TRUE;
}

OnCreate(){
  m_pxTop    = GetSystemMetrics(SM_YVIRTUALSCREEN);
  m_pxLeft   = GetSystemMetrics(SM_XVIRTUALSCREEN);
  m_pxRight  = GetSystemMetrics(SM_CXVIRTUALSCREEN);
  m_pxBottom = GetSystemMetrics(SM_CYVIRTUALSCREEN);

  //MonInfo is a callback function
  ::EnumDisplayMonitors(NULL, NULL, MonInfo, 0);
}

int myFunction()
{
    int x=0;
    return y;
}