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I have a DLL written in C++ that is used to modify parameters in VISSIM (traffic simulator). Within this DLL, I would like to call MATLAB to send data, perform MATLAB functions, and return data to the DLL. This all occurs outside of an IDE as VISSIM calls the DLL as necessary.

I have (1.) a working DLL that properly modifies VISSIM parameters and (2.) a working .cpp program that opens the MATLAB Engine (these two programs are currently separate - independent of each other).

How can I combine these two programs so that I can call the MATLAB engine from my existing DLL? A simple copy-paste of the .cpp MATLAB engine program into the DLL did not work (I also modified the DLL project properties to include the necessary MATLAB libraries/directories/paths as is done in the .cpp MATLAB engine program properties).

Note: The .cpp MATLAB engine program builds successfully with 'stdafx.h', but when copied to the DLL and then built, I receive fatal error C1083: Cannot open include file: 'stdafx.h' Perhaps this is an issue?

E. Wash
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This is an interesting dilemma as you would typically run MATLAB, or some other COM interface language, to control VISSIM which would load your custom DLL once a simulation begins. In your case you want the DLL to run MATLAB after VISSIM has started with a simulation.

I think your best approach is to use the first approach, the standard way of communication, but have a decentralized data exchange. One solution might be to have MATLAB start up VISSIM which will load the DLL when the simulation begins. The DLL could send data to a database, XML file, text file or other data container. MATLAB would need to monitor the data container for updates and send to VISSIM. This would be a bit slow but should work.

I have another idea but it requires a little research. Contact me if you would like to discuss. I have have been actively developing solutions for VISSIM for the last seven months using MATLAB, R, C++, and C#.

Brian O'Donnell
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  • Thanks for sharing your ideas. Since I am a beginner programmer, I am having difficulty with figuring out the interface architecture. A more detailed talk would be very helpful. Please see my profile for my email as I could not locate yours. – E. Wash Jul 08 '16 at 15:10