🚀 go-pugleaf

"Andrew" <alamb@tynetec.co.uk> wrote:

>I am trying to stop more than one instance of my app running at any one
>time, normally I use a mutex and this works fine, most of the applications
>we have developed have used Win 9x but now we have moved to win 2k and the
>mutex doesn't seem to work any more, I have also tried semaphores and the
>API function FindWindow, please see the following
>
>Using a mutex:
>
>        HANDLE mutex;
>        String mutexname = "Concierge.Server.mutex";
>        mutex = OpenMutex(NULL,false,mutexname.c_str());
>
>        if (mutex == NULL)
>            mutex = CreateMutex(NULL,true,mutexname.c_str());
>        else
>        {
>            MessageBox(0,"This application is already running.\n"
>                  "You may only run one instance at any one
>time","Error",MB_OK);
>            return 0;
>        }

Hmmm. That's not how my code does it. Basically, I go straight into
CreateMutex() and on return check GetLastError() to see if it's
ERROR_ALREADY_EXISTS.

In other words:

	SetLastError(0) ;
	m_Handle = CreateMutex(NULL, false, m_Name) ;
	return (GetLastError() != ERROR_ALREADY_EXISTS) ;

Alan Bellingham
-- 
alanb@episys.com