limiting number of instances in Windows terminal server

[Schokohase]

Zitat von imadam:

We were able limit this to one instance of the app on Windows Desktop.

I guess you use a mutex for that.

For Terminal Server (or even in generell) do not use a global mutex as this would be for the whole system.

For an application with one instance you need one mutex.
For an application with two instances you need two mutexes.
...

[Klaus01]

.. but whith muutexes you have to decide how many instances can be started - at design time.
These settings are then based on application level - not on user level.

best regards
Klaus

[mjustin]

Did you try TJvAppInstances already? It is designed for limiting app instances, and it allows to set the maximum number of simultaneous instances using the property MaxInstances. I am not soure however if it is also suited for a TS.

[Dalai]

Zitat von Klaus01:

.. but whith muutexes you have to decide how many instances can be started - at design time.

Uh, no. A Mutex is based on a name, a string, and strings can be built at runtime. Example from one of my projects where the mutex name is based on a concatenation of several strings:hMutex:= CreateMutex(nil, True, PRODUCTNAME + PRODUCTNAME + PRODUCTCOPYRIGHT); Using usernames and an appended counter instead is trivial. Reading the information that user A can start the application X times and user B can start it only once is trivial, too (Registry, INI, XML, whatever). Use that in conjunction with a for-loop that tries to create mutexes until either all of them already exist, or the maximum allowed instances are reached, and you have reached your goal.

Regards
Dalai

[imadam]

Zitat von Dalai:

Zitat von Klaus01:

.. but whith muutexes you have to decide how many instances can be started - at design time.

Uh, no. A Mutex is based on a name, a string, and strings can be built at runtime. Example from one of my projects where the mutex name is based on a concatenation of several strings:hMutex:= CreateMutex(nil, True, PRODUCTNAME + PRODUCTNAME + PRODUCTCOPYRIGHT); Using usernames and an appended counter instead is trivial. Reading the information that user A can start the application X times and user B can start it only once is trivial, too (Registry, INI, XML, whatever). Use that in conjunction with a for-loop that tries to create mutexes until either all of them already exist, or the maximum allowed instances are reached, and you have reached your goal.

Regards
Dalai

So far, my research gave me:
- I have to list processes in TS session
- I have to get username from TS enviroment which is logged in
and simple compare number of instances in question with number of those processes already running.
Is this wrong approach ?
Yet to figure out how to read logged user and processes over Win32 API .

[Dalai]

Yes, reading the number of processes running as user X is another possible approach. Unfortunately I don't know how to read the user a process runs as, even less when TS is involved.

Regards
Dalai

[hoika]

Hello,
use a GUID as (global) Mutex-Name with _1, _2 and so on.

if _1 is used, use _2.
if _x is used, you have your maximum instances ...

quick&dirty


or just said: use JEDI JvAppInst.pas
hey use some form of hidden window for each instance

[mjustin]

Zitat von Dalai:

Yes, reading the number of processes running as user X is another possible approach. Unfortunately I don't know how to read the user a process runs as, even less when TS is involved.

It is easy to count the instances running in the current session. Example in .Net:

Code:

private static int CountApplicationInstances()
    {
        var currentProcess = Process.GetCurrentProcess();
        var processes = Process.GetProcessesByName(currentProcess.ProcessName);

        // test if there's another process running in current session.
        var intTotalRunningInCurrentSession = processes.Count(prc => prc.SessionId == currentProcess.SessionId);

        return intTotalRunningInCurrentSession;
    }

(based on https://stackoverflow.com/a/36210660/80901)

[imadam]

Zitat von mjustin:

Did you try TJvAppInstances already? It is designed for limiting app instances, and it allows to set the maximum number of simultaneous instances using the property MaxInstances. I am not soure however if it is also suited for a TS.

We tested this: http://www.delphidabbler.com/articles?article=13&part=4 and this works on Windows 10 limiting to 1 instance. But it doesn't work on TS. It actually on TS allows only one user to run only once instance. Whom ever get first to it

[mjustin]

Zitat von imadam:

Zitat von mjustin:

Did you try TJvAppInstances already? It is designed for limiting app instances, and it allows to set the maximum number of simultaneous instances using the property MaxInstances. I am not soure however if it is also suited for a TS.

We tested this: http://www.delphidabbler.com/articles?article=13&part=4 and this works on Windows 10 limiting to 1 instance. But it doesn't work on TS. It actually on TS allows only one user to run only once instance. Whom ever get first to it

Ok, the code on (http://www.delphidabbler.com/articles?article=13) does not use the JVCL TJvAppInstances, but good to know

I also posted another suggestion (see #18)