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6064 :: Multithreading: still .running after joinThreads()

• nroach2 (orginal) [2020-03-11T21:00:57+01:00] view original

  Hi all, Relatively new to nim, very new to multithreading in nim. I'm attempting to run a program on a bunch of files I have the file paths for. The relevant code at the moment is the following:

  var t1 : seq[Thread[(string,string,string,uint16,uint16)]]
  for file in files:
    while true:
      if t1.len < int(thread_num):
        t1.add(Thread[(string,string,string,uint16,uint16)]())
        createThread(t1[t1.len - 1], myFunction, (file, ... <other stuff>))
        break
      else:
        var added_flag = false
        for i,thr in t1:
          if not t1[i].running:
            t1[i] = Thread[(string,string,string,uint16,uint16)]()
            createThread(t1[i], myFunction, (file, ... <other stuff>))
            added_flag = true
            break
        if added_flag:
          break
      os.sleep(1)
  joinThreads(t1)
  for thr in t1:
    assert not thr.running
  Run

  I would expect all the threads in t1 to have finished running by the time I hit my assert statement, because I used joinThreads(), but that doesn't seem to be the case. Is my logic totally off? Am I misunderstanding how to properly use nim threads and joinThreads() in particular? Any help you could provide would be much appreciated.

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• nroach2 (orginal) [2020-03-11T21:12:41+01:00] view original

  Also, not sure if it's relevant, but I think it might be. The function I'm calling is launching processes with the osproc module. Processes that in some case may take a while to run.

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• mratsim (orginal) [2020-03-12T16:22:14+01:00] view original

  If your function is execProcess You can just use execProcesses instead to have multi-processing.

  Your Thread[(string,string,string,uint16,uint16)] seems dangerous due to the strings not being GC-safe.

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• nroach2 (orginal) [2020-03-15T16:06:03+01:00] view original

  Thank you for the feedback! Unfortunately the function is not just an execProcess, it's just one step in the larger function.

  Is there a work around for the GC-safe problem with passing string s? I need to pass the directory and file handles for the files I'm working with somehow...

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