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Hello, I am trying to figure out, if it is possible to create a native LabVIEW I/O interface to C/C++ code, that is using the I/O functions through callbacks. The scenario is as follows: I made a toolkit to process multimedia formats and (so far only) video codecs, it is using internally FFmpeg shared objects (DLLs or SOs, further just "DLLs"). They way the FFmpeg DLLs access I/O is through callback mechanism. Following all happens in the wrapper. If I want the toolkit to read data from some I/O like network or disk, I have to create a session, and part of the session are function pointers to callbacks doing various tasks, one of them is reading data. Anytime a user tries to read more data (1 data packet), he forces a call to the session demuxer, that further uses the I/O callback so long, until it parses one packet/hits EOF/corrupt data/etc..., now this works nicely if you want to provide data through standard means like video file or stream URL. Since the capabilities of FFmpeg allow for example (de)muxers and codecs for images, I thought it would be cool to give the user possibility to supply his own data, that he reads via LabVIEW from database or whatever. Not just limit the usage of I/Os implemented inside the DLLs. All I know, is that I cannot use VIs as callbacks inside C/C++ code, so the only way is to somehow "decallback" the implemented I/O mechanism.