Re: Multiple instances of a single DLL

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Stefan, Nikolaos,

Thanks for your replies.

Yes, my dll contains global data, which is the root of my problem.
Sorry, I should have been more specific about it.

I initially ruled out TLS for a reason that I now realize was stupid. I'll investigate that route.

Thanks for pointing out the limit on threads per process.

Serge.
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"Nikolaos D. Bougalis" <nikb@xxxxxxxxxxxxx> wrote in message news:_9hej.26808$db7.8758@xxxxxxxxxxxxxxx
Stefan Kuhr wrote:
Hello Serge,


Serge Wautier wrote:
<snip>
The code of the data logger can also be compiled as a DLL and loaded by a Windows exe that acts as a virtual machine to simulate the device. Very helpful for basic debugging.

Now I want to load test the server (the device sends its info to a web server by GPRS).

My idea is to create a bunch of threads. Each thread is a single virtual machine, therefore owns a copy of the data of one DLL 'instance'.



As long as your DLL doesnt have per-DLL-instance data (read: "globals"), you need not make copies of your DLL to simulate your virtual machine. However, if your DLL uses globals, there is no other way than what you already proposed.

Please don't answer questions to which you don't know the answer to. That's _EXACTLY_ what TLS is for. You can find out more about how it works and how to use it on the nice MSDN page that explains how it works: http://msdn2.microsoft.com/en-us/library/ms686749.aspx.


-n

.

Relevant Pages

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    ... Yes, my dll contains global data, which is the root of my problem. ... I initially ruled out TLS for a reason that I now realize was stupid. ... If you don't have the DLL source code, then you basically will require a separate process to host each instance of the DLL, it's the only way for the data addresses placed in the code by the compiler to refer to different instances, because each process gets its own page table. ... His original post detailed a single process with multiple threads, each of which had its own copy of certain global variables, which is exactly what TLS is. ...
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