On Mon, 12 May 2008 17:35:44 -0700 (PDT), schickb <[EMAIL PROTECTED]> wrote:
I'm trying to pipe data that starts life in an array('B') object through several processes. The code below is a simplified example. The data makes it through, but the wait() always hangs. Is there a better way to indicate src.stdin has reach EOF?from subprocess import Popen, PIPE from array import array arr = array('B') arr.fromstring("hello\n") src = Popen( ["cat"], stdin=PIPE, stdout=PIPE) dst = Popen( ["cat"], stdin=src.stdout) arr.tofile(src.stdin) src.stdin.close() dst.wait()
Alas, you haven't actually closed src's standard input. Though you did close src.stdin, you didn't close the copy of it which was inherited by dst! So though the file descriptor is no longer open in your main process, it remains open due to the reference dst has to it. You can fix this by having Popen close all file descriptors except 0, 1, and 2 before it execs cat - pass close_fds=True to the 2nd Popen call and you should get the behavior you want. Jean-Paul -- http://mail.python.org/mailman/listinfo/python-list
