Roger

[Prevent an application from ru]

Hello everyone,


I wrote an application using VC++.


How do I prevent a user from running it when another one is already

running? In short, what are the codes for detecting that another version

is already running?


The amateurish way is to wrong something to a temp file but this

will not work if the application crash halfway.


Please reply.


Thanks.

regards,

ywshum

[Reshmi]

Hi,

I think you can find the instance using FindWindow.

Suppose your application has a caption IDS_CAPTION

CString szCaption;

szCaption.LoadString(IDS_CAPTION);

HWND hWnd = FindWindow(NULL, szCaption);

if (!hWnd) return FALSE;//no instance found

AfxMessageBox(IDS_EXIST);//if an instance found messagebox that an

//instance already exists

return TRUE;


Then based on the return value of this you can stop running another instance.


Thanks,

Reshmi

[sally]

you can create a CMutex object with your own special string as a name for it


if you can create the CMutex, this is the first instance, and when the app exists you close the CMutex

if you can not create it, your app is already running


Sally

[S Cheeran]

BOOL CAIAWashChartApp::InitInstance()

{

AfxEnableControlContainer();

// Allow to run only single instance of ControlWoks

HWND hwnd = ::FindWindow(0, "AIA ControlWorks"

if(NULL != hwnd)

{

TRACE("One Instance of ControlWorks is already running\n"

if(::IsIconic(hwnd))

{

::ShowWindow(hwnd, SW_RESTORE);

}

else

{

::SetForegroundWindow(hwnd);

}

return FALSE;

}

.

.

.

.

}

[Peter Lundqvist]

Hi. Try this!

In the App's .H -file add a CEvent *.

#include <afxmt.h> // CEvent

class YourApp : public CWinApp

{

...

...

...

private:

CEvent* m_pInstanceEvent;

};

// Add this In the App's .cpp -file //

/////////////////////////////////////////////////////////////////////////////

// CYourApp construction

CYourApp::CYourApp()

{

// TODO: add construction code here,

// Place all significant initialization in InitInstance

m_pInstanceEvent = NULL;

}

/////////////////////////////////////////////////////////////////////////////

// CYourApp destruction

CYourApp::~CYourApp()

{

// kill the instance handle

if (m_pInstanceEvent != NULL)

{

delete m_pInstanceEvent;

m_pInstanceEvent = NULL;

}

}

BOOL CYourApp::InitInstance()

{

// Do we already have an Instance of the App?

m_pInstanceEvent = new CEvent(FALSE, FALSE, AfxGetAppName());

if (::GetLastError() == ERROR_ALREADY_EXISTS)

{

// End this Instance

m_pInstanceEvent->SetEvent();

return FALSE;

}

...

...

...

return TRUE;

}


Good Luck!


/Peter Lundqvist