showing main window of prev running application

[chander]

if a prev existance of application is running and i again run another instance of tht application then i want to popup that prev. application's main window in front as happens in Messengers .. and terminate newly created instance what to do for tht ..

some thing like this in VB

if app.previnstance then

' popup main window/form of previos running application
termination of newly instance of application ..

endif

ne idea on it ??

[CornedBee]

You'd use a named mutex object for this - look it up in MSDN

[gwdash]

HANDLE hMutex;

int WINAPI WinMain(HINSTANCE hInst, HINSTANCE hPrevInst, LPSTR lpCmdLine, int nCmdShow)
{

  hMutex = CreateMutex( NULL, FALSE, _T("ApplicationName") );
  if ( hMutex && (GetLastError() == ERROR_ALREADY_EXISTS )) {
    //Find Correct Window&Send to front;
  }

//.....blah blah blah
  return 0;
}

[Chris]

how abt this? AS i does not use Mutex before, pls coreect me, if my method is not a proper way

int APIENTRY WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
    // Check for previous instance
    hWnd = FindWindow(TEXT("ClassName"), TEXT("WindowsTitle"));
    if (hWnd != NULL)
    {
        // Show the previous window
        SetForegroundWindow(hWnd);
        // Unload the current instance
        return false;
    }

    // Register application define class into windows system

    // Perform application initialization:

    // Main message loop:
    while (GetMessage(&msg, NULL, 0, 0)) 
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }

    return msg.wParam;
} 

[CornedBee]

Chris: This method works too, as long as the app has a non-dialog main window.

SetForegroundWindow is API and is used to bring the existing app to top.