I have a program I'm running within another. The parent program freezes up while the child process is running. Is there a way to run the child process in the OS as a parent process itself?
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What you want is a separate thread – keyser Jul 16 '14 at 17:33
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1When you say you have programs running "within" one another, do you mean one Python script calling another, a Python script launching other programs, a Python script whose functions you want executed in a subprocess, or something else? – skrrgwasme Jul 16 '14 at 17:48
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Scott: In Maya (3D app) I'm trying to run an external program. The external program 'locks up' Maya when it is running. I get control of Maya when I close the external/child program. Does that help? Sorry, bit of a newb. – john Jul 16 '14 at 18:31
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You can use subprocess.Popen, assuming you're really trying to launch a program that's completely separate from the parent Python script:
import subprocess
subprocess.Popen(["command", "-a", "arg1", "-b", "arg2"])
This will launch command as a child process of the calling script, without blocking to wait for it to finish. If the parent exits, the child process will continue to run.
dano
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I got this to work outside of a function, but when in a function it doesn't run a detached subprocess.
import subprocess def myFunc(): #do stuff subprocess.Popen("C:\myProgram.exe") myFunc()– john Jul 16 '14 at 18:40 -
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If you really want to have independent processes, please have a look at the multiprocessing module. If it is enough to have a separate thread running in the same OS process, then use threading. Or are you interested in starting an external program from within a Python script with subprocess?
Unfortunately, the terminology is a bit confusing. For example, in Linux "thread" and "process" are both independent processes with no real difference. In python "process" is a separate OS precess, thread runs in the same OS process.
For more information on these, you might have a look at this question: Multiprocessing vs Threading Python
