I discovered through trial and error that the CNVCreateBufferedWriter function, while it does provide buffering when necessary to preserve data until it can be written within a process, it does not provide for arbitration between writes originating from multiple processes. Stated another way: As far as I am aware, a single Network Variable process is not designed be written to by more than one application.
The documentation was not clear on this point. It states “You can buffer data to be written to the network variable by calling CNVPutDataInBuffer. The system automatically writes the buffered data to the network variable.” This suggested to me that arbitration of some kind existed to handle asynchronous writes by multiple applications. I confess, my interpretation may have been driven by wishful thinking to support my application needs.
Nevertheless, my suggestion is that future versions of this library include a capability to arbitrate asynchronous writes from multiple applications to a single network variable. i.e., that two, or three, or more applications can successfully connect to and write to the same network variable.
