Re: How to limit the number of instances of an application on a server?

From:

"Karsten Schulz" <kahnpost@freenet.de>

Newsgroups:

microsoft.public.vc.mfc

Date:

Wed, 11 Jun 2008 10:02:28 +0200

Message-ID:

<emlc#l5yIHA.4864@TK2MSFTNGP06.phx.gbl>

Hi Phil,

this Situation is only handable via the sytemregistry/FileIO action by
Application Start/End.
U count a reference in registry up (same do COM) . And here too user can
change it at will.

www.aladin.com u can install a Dongle, and u have the same Senario ->
www.brstudio.com

U cant protect a doublicate instance, if an BackwardEngeneer has the force.

Check ur Windows Name :
BOOL CALLBACK CMyApp::searcher(HWND hWnd, LPARAM lParam)
{
    DWORD result;
    LRESULT ok = ::SendMessageTimeout(hWnd,
                                      UWM_ARE_YOU_ME,
                                      0, 0,
                                      SMTO_BLOCK |
                                      SMTO_ABORT_IF_HUNG,
                                      200,
                                      &result);
    if(ok == 0)
       return TRUE; // ignore this and continue
    if(result == UWM_ARE_YOU_ME)
    { /* found it */
        HWND * target = (HWND *)lParam;
        *target = hWnd;
        return FALSE; // stop search
    } /* found it */
    return TRUE; // continue search
} // CMyApp::searcher
//--------------------------------------------------------

BOOL CMyApp::InitInstance()
{
    bool AlreadyRunning;

    HANDLE hMutexOneInstance = ::CreateMutex( NULL, FALSE,
   _T("MYAPPNAME-088FA840-B10D-11D3-BC36-006067709674"));

          // what changes for the alternative solutions
          // is the UID in the above call
          // which will be replaced by a call on
          // createExclusionName

    AlreadyRunning = ( ::GetLastError() == ERROR_ALREADY_EXISTS ||
                       ::GetLastError() == ERROR_ACCESS_DENIED);

And Create a Mutex :

BOOL CALLBACK CMyApp::searcher(HWND hWnd, LPARAM lParam)
{
    DWORD result;
    LRESULT ok = ::SendMessageTimeout(hWnd,
                                      UWM_ARE_YOU_ME,
                                      0, 0,
                                      SMTO_BLOCK |
                                      SMTO_ABORT_IF_HUNG,
                                      200,
                                      &result);
    if(ok == 0)
       return TRUE; // ignore this and continue
    if(result == UWM_ARE_YOU_ME)
    { /* found it */
        HWND * target = (HWND *)lParam;
        *target = hWnd;
        return FALSE; // stop search
    } /* found it */
    return TRUE; // continue search
} // CMyApp::searcher
//--------------------------------------------------------

BOOL CMyApp::InitInstance()
{
    bool AlreadyRunning;

    HANDLE hMutexOneInstance = ::CreateMutex( NULL, FALSE,
   _T("MYAPPNAME-088FA840-B10D-11D3-BC36-006067709674"));

          // what changes for the alternative solutions
          // is the UID in the above call
          // which will be replaced by a call on
          // createExclusionName

    AlreadyRunning = ( ::GetLastError() == ERROR_ALREADY_EXISTS ||
                       ::GetLastError() == ERROR_ACCESS_DENIED);

greetings
Karsten Schulz
(www.kahnsoft.de)

"Phil" <pbruyant@yahoo.com> schrieb im Newsbeitrag
news:b3c14334-f2c6-485c-86d4-91d480661905@l42g2000hsc.googlegroups.com...

On 9 juin, 15:19, "Karsten Schulz" <kahnp...@freenet.de> wrote:

Hi Phil,
the internal processlist dont crrelates with users,they enumerate all
running Processes on the mashine.
U can easy count the name of ur modulename, by comparisation the
processlistnames.

Te name of your Application u can find out on different ways:
char
Fname[MAX_PATH];GetModuleFileName(NULL,Fname,sizeof(Fname)/sizeof(Fname[0]));
or
LPCSTR pAppName=AfxGetApp()->m_pszAppName

try it in a console app.
greetings
Karsten Schulz

"Phil" <pbruy...@yahoo.com> schrieb im
Newsbeitragnews:c988a1a7-1a25-46c3-839c-11d664814130@59g2000hsb.googlegroups.com...

On 9 juin, 13:56, "Karsten Schulz" <kahnp...@freenet.de> wrote:

Hi Phil,

u can enumerate al running Processes easy,

greetings and Best Regards
Karsten Schulz

--www.kahnsoft.de

Thanks
Can this code find instances of the application when run by the other
users ?

-P

I now see a major drawback to this solution: process.szExeFile
contains the name of the .exe file (same thing for the module's name
in it). Thus, if one creates a copy of the .exe file with another
name, your code sees it as a different program, not as a new instance
of the same program.
-P