How to get exit code when using Python subprocess communicate method?

Question

How do I retrieve the exit code when using Python's subprocess module and the communicate() method?

Relevant code:

import subprocess as sp data = sp.Popen(openRTSP + opts.split(), stdout=sp.PIPE).communicate()[0] 

Should I be doing this another way?

Answer 1

Popen.communicate will set the returncode attribute when it's done(*). Here's the relevant documentation section:

Popen.returncode    The child return code, set by poll() and wait() (and indirectly by communicate()).    A None value indicates that the process hasn’t terminated yet.    A negative value -N indicates that the child was terminated by signal N (Unix only). 

So you can just do (I didn't test it but it should work):

import subprocess as sp child = sp.Popen(openRTSP + opts.split(), stdout=sp.PIPE) streamdata = child.communicate()[0] rc = child.returncode 

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(*) This happens because of the way it's implemented: after setting up threads to read the child's streams, it just calls wait.