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7249 :: startProcess help (2)

• Lecale (orginal) [2020-12-13T13:19:27+01:00] view original

  First the background, I would like to interact with a exe file. In a repeatable fashion, I give it a command like "play black e5" and I would like to then query the output from the command "vn_winrate" To do this I thought that it must be best to use StartProcess, but I am a bit lost as to how to interact with the program. I tried the below, but it directly returned -1 as the exit code, which surprised me. ''var pig: Process = startProcess(command = "Leela0110GTP.exe", options ={poInteractive})'' How do I keep alive, or even just initiate the stdin and stdout and stderr streams. Can anyone show me an example somewhere.

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• jrfondren (orginal) [2020-12-13T13:48:13+01:00] view original

  There's a lot to decide per use of startProcess, but here's an example:

  
  import osproc, strutils, streams
  
  let p = startProcess("perl", args = ["-ne", "$|=1; print; exit if $.>1"],
    options = {poInteractive, poUsePath})
  let (fromp, top) = (p.outputStream, p.inputStream)
  
  top.write "repeat this please\n"
  top.flush
  echo fromp.readLine.toUpper
  
  top.write "and this\n"
  top.flush
  echo fromp.readLine.toUpper
  
  discard p.waitForExit
  Run

  That starts a Perl process which echos what's written to it without buffering and exits after printing twice. The Nim then writes two strings, flushes them so they're definitely sent, reads them back, and prints them in upper case, one at a time.

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• Lecale (orginal) [2020-12-28T08:00:38+01:00] view original

  Thanks. I've been able to get started on what I wanted to do now. The main problem was that I was missing a couple of command line arguments which were essential to the process I was trying to interrogate. (oopsy!)

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