Reopening serial port fails if not closed properly with CloseHandle

Question

I am working with USB device on Windows that is seen as a virtual serial port. I can communicate with the device using CreateFile and ReadFile functions, but in some cases m

Answer 1

Is there any possibility that some threads or child processes of your crashed program are still running and holding a copy of the file handle? Perhaps a debugger process is still open? If so, those might be keeping the device open. I'd check Task Manager just to be sure; if so, force-killing the leftover processes might fix the problem.