How to enable Thread Local Storage in a DLL generated by application builder?

[HermanChan]

I used application builder to build a DLL. I had VC6 codes to load the DLL explicitly. Every time I called LoadLibrary, the handle returned is the same.
I want each thread within my application to have its own copy of the DLL's variable. How to do it? Thanks.

[rolf]

HermanChan wrote:

> I used application builder to build a DLL. I had VC6 codes to load the
> DLL explicitly. Every time I called LoadLibrary, the handle returned
> is the same.
> I want each thread within my application to have its own copy of the
> DLL's variable. How to do it? Thanks.

I don't think you can do that. A DLL is always loaded into a process
only once. There isn't such a thing as a separate DLL handle between
threads. Thread Local Storage (TLS) is as far as I know something
different which needs to be taken care of in the DllMain function of
the Dll. But for a LabVIEW generated DLL you have no way of changing
the behaviour of the LabVIEW provided Dll entry function.

Rolf Kalbermatter

[HermanChan]

Is there any setting in VI, like VI properties or inside the application builder, to achieve that?

[Jeremy Braden]

You might try making the VIs renterant (vi properties >> execution )before you build the application.

[HermanChan]

I tried.
When I made VIs renterant, the front panel didn't popup in my MFC application.

[rolfk]

No! TLS is a rather tricky thing and if you don't know exactly how to work with it you cause more problems than you try to solve. As far as I know it also depends on the compiler and its runtime libraries how you can use that.
As you can see I have not really bothered even in my C programming to do that.

[rolfk]

Yes, reentrant VIs do not update their front panels and are definitely not meant to be used as GUI.