Hello, According to my experience and from what I've read in other threads, subprocess isn't easy to use for interactive tasks. I don't really know, but maybe it wasn't even designed for that at all.
On the other hand, pexpect seems to work fine for interactive use and even provides a method for nonblocking reads, so I think that you should consider to take a look at it: http://pexpect.sourceforge.net/pexpect.html#spawn-read_nonblocking Best regards, Javier 2009/7/31 Dhanesh <dhanesh...@gmail.com>: > Hi , > > I am trying to use subprocess popen on a windows command line > executable with spits messages on STDOUT as well as STDIN. Code > snippet is as below :- > ########################################################################## > sOut="" > sErr="" > javaLoaderPath = os.path.join("c:\\","Program Files","Research In > Motion","BlackBerry JDE 4.7.0","bin","Javaloader.exe") > cmd = [javaLoaderPath,'-u','load','helloworld.jad'] > popen = subprocess.Popen > (cmd,bufsize=256,shell=False,stdout=subprocess.PIPE, > stderr=subprocess.PIPE) > while True: > sErr = sErr + popen.stderr.read(64) > sOut = sOut + popen.stdout.read(64)------------------> Blocks > here > if None != popen.poll(): > break; > ########################################################################## > > I observed that python scripts blocks at stdout read on the other hand > when I do not create a child stdout PIPE say " stdout=None" , things > seems to be working fine. > > how can I we have a non blocking read ? > And why does stdout block even where data is available to be read > ( which seem to be apparent when stdout=None, and logs appear on > parents STDOUT) ? > > -- > http://mail.python.org/mailman/listinfo/python-list > -- http://mail.python.org/mailman/listinfo/python-list
