兩個進程之間通信

extern "C"  _declspec(dllexport) int  LCControlData(long  data1,long  data2,long  data3)
   {
 COPYDATASTRUCT cds;
    cds.dwData = 0xCCCC;

 long data[3];
 data[0]=data1; data[1]=data2; data[2]=data3;
    cds.cbData = sizeof(long)*3;
    cds.lpData = (void*)data;
   
 CWnd *pTraceWnd=CWnd::FindWindow("HWClass",NULL);
 if(pTraceWnd)
 {
  pTraceWnd->SendMessage(WM_COPYDATA,NULL,(LPARAM)&cds);
  return 1;
 }
 return 0;
   }