Is there anyway to open multiple instances of a dll?

Question

I have a dll in which controls an instrument. I need to communicate to multiple instruments with this dll. This dll only supports 1 instrument at a time. Is there anyway to load multiple instances of this dll and call same functions from each dll instance for different instrument.
Thanks.
CVI 2010
LabVIEW 2011 SP1
Vision Builder AI 2011 SP1

Answer 1

The idea as I understand it is something like this:
HANDLE MyLoadLibrary(LPSTR dllname)
// check in a global list if the DLL is already loaded
// if it is
// copy it to the temp directory with a different name and load it from there with LoadLibrary()
// else
// LoadLibrary() the requested DLL
// store the DLL name and handle in our global list
// return the handle
void MyFreeLibrary(HANDLE handle)
// search the handle in our global list and remove the entry
// FreeLibrary(handle);
That all said it may work for a particular driver but more likely the driver will stumble somewhere over the fact that its functions expect to have exclusive control over certain lower level resources. It's definitely a sure way into maintenance nightmare and you should consider to use or create a different driver almost at all costs if possible at all.
Rolf Kalbermatter
CIT Engineering Netherlands
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