Dick Holmes wrote: > https://occovid19.ochealthinfo.com/coronavirus-in-oc
> I'm trying to > communicate using a continuing dialog between two > processes on the same system. I think pexpect https://pexpect.readthedocs.io/en/stable/index.html does this naturally, but I don't know if Windows support is sufficient for your needs. > I've looked at various mechanisms and the > class that seems to fit my needs is Popen in the subprocess module, but > I can't seem to get more than a single round-trip message through Popen. > I first call Popen then poll using the identifier returned from the call > and the poll seems to work. I then call the communicate function passing > None as the value to send to the companion process stdin. I get the > expected result, but I also get "Exception condition detected on fd 0 > \\n" and "error detected on stdin\\n". Subsequent attempts to > read/write/communicate with the subprocess fail because the file (stdxx > PIPE) is closed. > > I can't tell from the documentation if the communicate function is a > one-time operation. Yes, communicate() is one-off, """Interact with process: Send data to stdin and close it. Read data from stdout and stderr, until end-of-file is reached. Wait for process to terminate. ... """ seems pretty clear. What would you improve? > I have tried using read but the read call doesn't > return (I'm using winpdb-reborn to monitor the operations). Try readline(). Deadlocks may happen ;) > I'm using Python 3.7, Windows 10, winpdb-reborn 2.0.0, rpdb2 1.5.0. If > it makes any difference, I'm trying to communicate with GDB using the MI > interpreter. > > Thoughts and advice appreciated! > > Dick -- https://mail.python.org/mailman/listinfo/python-list
