Python等待子进程完成

Question

I'm really new to Python and I got a little problem with the subprocess class.

I'm starting an external Program with :

      thread1.event.clear()
      thread2.event.clear()
      print "Sende Motoren STOP"
      print "Gebe BILD in Auftrag"
      proc = Popen(['gphoto2 --capture-image &'], shell=True, stdin=None, stdout=None, stderr=None, close_fds=True)
      sleep (args.max+2)
      thread1.event.set()
      thread2.event.set()
      sleep (args.tp-2-args.max)

My Problem is that in my shell where I Started the Python script, I still get the outputs of GPHOTO2 and I think Python is still waiting for GPHOTO to finish.

Any ideas?

Answer 1

The documentation for subprocess.Pope states:

stdin, stdout and stderr specify the executed programs' standard
input, standard output and standard error file handles, respectively.
[...]
With None, no redirection will occur; the child's file handles will be
inherited from the parent.

So you might want to try something along the lines of this. Which btw. blocks until completion. So you might not need the sleep() (here the wait() from subprocess.Popen might be want you want?).

import subprocess

ret_code = subprocess.call(["echo", "Hello World!"], stdout=subprocess.PIPE);