C / C++ / MFC

...
  case WM_DEVICECHANGE:
  {
    PDEV_BROADCAST_VOLUME pVol = (PDEV_BROADCAST_VOLUME)lParam;
    switch(wParam)
    {
      case DBT_DEVICEARRIVAL:
      {
        if(pVol->dbcv_devicetype == DBT_DEVTYP_VOLUME)
        {
          pVol->dbcv_unitmask; // test this mask for one or more volume letters (bit flags)
          MessageBox(NULL,_T("FOUND"), _T(""),MB_OK);
        }
      }
      break;
      case DBT_DEVICEREMOVECOMPLETE:
      {
        if(pVol->dbcv_devicetype == DBT_DEVTYP_VOLUME)
        {
          pVol->dbcv_unitmask; // test this mask for one or more volume letters
          // may be consisting of more than one bit flag (ORed together)

          MessageBox(NULL,_T("REMOVED"), _T(""),MB_OK);
        }
      }
      break;
  }
  break;
...

Ozer Karaagac wrote:

Does your device generate something other than DBT_DEVTYP_VOLUME as dbcv_devicetype member of the structure

Ozer Karaagac wrote:

dbcv_unitmask in case DBT_DEVICEREMOVECOMPLETE

DWORD dwTestMask = 1;
char archVols[32];
int nCount = 0;

for(int i = 0; i < 26; i++)
{
    if(pVol->dbcv_unitmask & dwTestMask)
       archVols[nCount++] = 'A' + i;

    dwTestMask <<= 1;
}

sawerr wrote:

If one application grabs a port no other application can use it.

sawerr wrote:

So, for example,that means one computer mustn't have 2 or more web server that listening port 80. Right?

sawerr wrote:

But also a lot of clients can connect same port.

SOCKET sConnection = socket(AF_UNSPEC, SOCK_STREAM, IPPROTO_TCP); //Create a TCP stream socket with any address type (IPv4, IPv6, ...)
//pAddress = get listening address, usually 0.0.0.0
bind(sConnection, pAddress->ai_addr, pAddress->ai_addrlen);
listen(sConnection, SOMAXCONN);
for (;;) {
    SOCKADDR saClient;
    DWORD nClientAddrLen = sizeof(saClient);
    SOCKET sClient = accept(sConnection, &saClient, &nClientAddrLen);
    CreateThread(); //Create a new thread to handle the new connection
    //Now wait for the next connection in the new loop
}

LRESULT CALLBACK DlgProc(HWND hwnd, UINT Msg, WPARAM wParam, LPARAM lParam) {
    switch (Msg) {
        case WM_INITDIALOG:
            break; //You can do whatever here

        case WM_COMMAND:
            switch (LOWORD(wParam)) {
                case IDC_MYBUTTON:
                    return 0; //something happened to MYBUTTON
            }
            break; //We havn't handled it, use default handler

        case WM_CLOSE:
            //cleanup
            return 0;
    }
    return pOriginalProcedure(hwnd, Msg, wParam, lParam); //This is set as GetWindowLong(GWL_MSGPROC) before changing the procedure.
}