os.waitpid doesn't return a tuple containing pid, and its exit status
Question: I try to come up with a workaround for this [python
bug](http://bugs.python.org/issue3905) calling `subprocess`. I figured the way
to go is using `os.system` in combination with `os.waitpid`. To test this I
wrote the code below. `system_call_test.py` writes the `pid` and lot's of text
to the file `f`. But calling `os.waitpid()` always get me this error:
`OSError: [Errno 10] No child processes`. So I'm having a hard time to check
if this construct is working properly. How can I ensure that the script waits
for the termination of the other. I'm on windows XP/ python 2.7.

    
    
    import os
    f = r'D:\temp\called.txt'
    
    s = os.system('C:\Python27\python.exe D:\python_spullen\system_call_test.py')
    with open(f, 'r') as f_in:
        i = f_in.readline()[-4:]
        print i
        rr = os.waitpid(int(i),0)
        print rr
    


Answer: `os.system` returns [the exit code of the
process](http://stackoverflow.com/questions/6466711/what-is-return-of-os-
system-in-python). So `s` above is already populated and the process has
exited. `os.waitpid` has nothing to wait on.

