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Using call library function on a dll file created in an old version of labview

Update:10-11Source: network consolidation
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So I'm trying to update an old labview program to work in labview 2012. Everything converted over just fine but labview will always crashoverwrote some while using a  library function in a DLL that was compiled using labview 8.5. Labview exits, stating that it vital memory area. It passes an array of data to the library call and an empty array for output. I thought I could get around this problem by changing my code to initialize the array being passed in so that it would be large enough to hold all the expected output. Now instead of overwritting areas of memory it shouldn't, I get a pop up message that says:
fatal internal error
memorymanager.cpp line 406
8.5.1.f5 
So it appears because I don't have the ability to recompile the DLL file it runs off of the 8.5 runtime instead of the more recent one. Is there any thing I can do about this?

The Best Answer

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rjpierce wrote:
So I've been trying to figure out a way around this on my own while waiting on a response. From what I'm reading, a dll created in one version of the labview runtime can't be used by a different labview runtime. Am I correct in this? I feel like I must be mistaken since that's basically the opposite of how a dll should work. If nothing else works I have access to the original code for the DLL but it requires the control and simulation toolkit. I would like to avoid having to recompile the DLL since it was put in to a DLL to avoid the need for the toolkit to begin with. 
Your problem most likely is that you try to pass native datatypes to the DLL function? That only can work if the caller and callee use the same LabVIEW runtime engine. Otherwise the memory block created in the memory manager of the caller will be accessed by the memory manager in the callee and bad things happen. Instead you should define the DLL function to use standard C datatypes (Pointer to C array) and also make sure to allocate the according buffer in the caller for all output array parameters.
An even more elegant way would be to completely abandon the DLL approach and call the according functions directly in LabVIEW. Then you won't have the problems about mismatched runtime engines. Passing C array pointers to a DLL is less performant than passing native datatypes, but if you use native datatypes you have to make sure the DLL is compiled in the same LabVIEW version as the one you call it from.
Rolf Kalbermatter
CIT Engineering Netherlands
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