Problem with pipes (win32pipe)

[Jeremy Gibson]

I am having a bear of a time trying to get my python program to talk to a
windows process.  The program I am trying to run is call nrcmd.  It is a 
cisco program that is used for administering router clusters.

Here is what I have done so far(BTW) the kludgey readlines are going to
be replaced with some pattern matching I just wanted to get talking first.

*****************************************************
import os, win32pipe
os.chdir('c:\\program files\\network registrar\\bin')
fin, fout = win32pipe.popen2('nrcmd')
c = 0
while c < 6:
	fout.readline()
	c = c+1
fout.read(7)
*****************************************************

The output from this is:
*****************************************************
100 Ok\n
	cluster = nnn.nnn.nnn.nnn\n
	default-format = user\n
	user-name = user \n
	visibility = 5\n
nrcmd> 
*****************************************************

At this point any fin.write() will be accepted without complaint, but
nothing is happening.  If I attpempt to fout.read() again the program
hangs and must be killed.  I assume this is happening because I am
attempting to read a null byte. The return from a successfull (or
unsuccessfull) write should fill the fout buffer with something to read.

I am sending newlines in the fin.writes I've tried and I've even tried
sending \r\n since this is a windows machine I'm working with.  I've also
tried fin.flush() after a write.  

If anyone has any ideas or thoughts on where I might find illumination
for this problem please write to my email, or post to the group.

Thanks,
Jeremy Gibson