Error #75 at Open {file} For Input As #1 (need 2 progs on same PC to communicate)

[madscijr]

I would agree that the file input like that is likely to cause problems, files really aren't made for that kind of task. Your best QB64 option would be a TCP/IP connection between the two programs, which overall is fairly easy to implement. If you have the main program start the mouse program then you can even pass the connection details as an argument to avoid hard-coding them between the programs.

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Using a "pipe" is another option, but those aren't exposed in QB64 so it would be a bit more complex.

Thanks for your reply - those examples are nice and short, I look forward to giving them a try. 
By "pipe" do you mean one prog calling another with command line args, or something else, like a program sending args to a different application already running? 
Thanks again!