Can I limit the no of instances od an dll?

[svatasoiu]

Hi,

I'm interested to know if it possible to limit (or detect) the no of instances of an dll (VB6) that are running or are instantiated.
I would like to limit the no of instances from inside the dll, (if the no of instances reach a limit all the new tentative of instantiating will do something else (return a busy code...)

thank you,

Sorin

[Lethal]

You could create a counter in the class's initialize event and increment it by 1, and decrement it by 1 in the class terminate event.

[svatasoiu]

Lethal,

Thank you for answer.
This solution will work for a different clients? Practicly this dll will be called from a stored procedure on a SQL server, and I want to limit the no of instances that run at an time. I'm not sure if the instances will be able to comunicate if they are not created by the same client.

Thank you,

Sorin

[Lethal]

Sure it will work. What you will have to do is create an ActiveX EXE so it will run in a seperate process space as the client(s). Also, put the counter into a standard .bas module and make sure that the class's instancing property is set to multi use so all of the clients share the same instance of the component. Good Luck

[svatasoiu]

Lethal,

I tried your advice and I added an bas module where will be the counter.
The counter is incremented into the initialization of the class and decremented into the terminate sub.
The component type was changed to activeX.exe and all the clases are multiuse.
When I use diferrent clients, each instance generated by the each client report a counter of 1 (It seems that the instances does not share the module.
I hoped I didn't do any mistake, but my code does not work in the way you said.
Can you build a very small example for me.

Thank you,

Sorin

[Lethal]

Hmm...I just tried it and it worked for me. What I bet happened is that in the project proeperties, the threading options is set to 'Thread per object'. What this does is create a thread for each new object that a client creates. Meaning, each thread gets its own copy of the global data section. Try this, I just notied that you said you wanted to use a dll. So, create a dll, create a public counter in a bas module, and add the same code as I described above. This will allow you to stop the number of instances.