Having trouble converting popen2 to subprocess

Daniel Klein danielkleinad at gmail.com
Sat Nov 18 14:52:21 CET 2006


Here's a c routine that prints a single line :

#include <stdio.h>
main()
{
  printf ("Hello World!\n");
}

And now the Python program (called 'po.py') that uses 'popen2' :

import popen2
(fin, fout) = popen2.popen2(r'c:\home\hw.exe', -1, 't')
print fin.readline()
fin.close()
fout.close()

When this is run it properly outputs the one line from the c routine :

C:\>python c:\python\po.py
Hello World!

Now here is my attempt to use the 'subprocess' module :

from subprocess import *
p = Popen(r'c:\home\hw.exe', bufsize=-1, stdin=PIPE, stdout=PIPE,
universal_newlines=True)
fin = p.stdin
print fin.readline()
fin.close()

When this is run, I get no output :

C:\>python c:\python\sp.py


C:\>

As you can see, I get no exception.

I've tried various combinations of the Popen arguments with no joy.

The platform is Windows XP Pro, so I did not try things like
'close_fds'.

What am I missing ?

Daniel Klein



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