"Tiago Saboga" <[EMAIL PROTECTED]> wrote > what's happening in this simple example. I want to establish a > connection between my two threads by a os.pipe,
While its possible to use a pipe to communicate within a process its not very helpful and very rarely done. Usially queues are used for communication between threads > I was hoping to see the output of writer.py come out in real time But you aren't really using a thrwad in your code you are spawning a new subprocess using Popen and reading the output of that from a pipe. are you sure you really need to do that in a thread? You can simply dip into the pipe and read it on demand. The usual case for a thread is when you want to perform two tasks concurrently within the same process, not to run another parallel process., > ... but it is coming out all together when writer.py returns. Why? Dunno, it depends on what writer.py is doing. If its writing to stdout then the puipe should be able to read the rewsults as you go. >> from __future__ import with_statement >> import thread >> import subprocess >> import os >> >> def run(out): >> subprocess.Popen(['./writer.py'], stdout=os.fdopen(out, 'w')) >> >> def main(): >> out_r, out_w = os.pipe() >> thread.start_new_thread(run, (out_w,)) Why not just set up outw to the output of Popen? Using the subprocess pattern: pipe = Popen(cmd, shell=True, bufsize=bufsize, stdout=PIPE).stdout or in your case: f = subprocess.Popen(['./writer.py'], shell=True, stdout=subprocess.PIPE).stdout >> with os.fdopen(out_r) as f: So you don't need this >> while True: >> line=f.readline() >> if line: >> print '[main]', line And this should just work. And if you really want to do something else wehile the output of writer is being collected put all of the above into your run function. Its not clear to me that you really need a thread here? A simpler approach may work better. -- Alan Gauld Author of the Learn to Program web site http://www.freenetpages.co.uk/hp/alan.gauld _______________________________________________ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
