Thanks! If that is the case, i.e. the parent doesn't wait, is the code in my last post wrong? "result" could be nothing.
--- On Fri, 7/24/09, Diez B. Roggisch <de...@nospam.web.de> wrote: > From: Diez B. Roggisch <de...@nospam.web.de> > Subject: Re: Popen > To: python-list@python.org > Date: Friday, July 24, 2009, 12:35 PM > Tim schrieb: > > Thanks! Yes I mean subprocess.Popen. > > > > I was wondering the meaning of "asynchronously" > > Here is some code I am reading recently: > > " > > result = Popen(cmdline,shell=True,stdout=PIPE).stdout > for line in result.readlines(): > > if find(line,"Cross") != -1: > > return > float(split(line)[-1][0:-1]) " > > The computation in the program "cmdline" takes a long > time, at the end of which the results will be output to > stdout. > > > > "asynchronous" seems to mean Popen returns to the > parent process immediately and the parent and child > processes continue to be executed. > > However, if Popen returns immediately to the parent > process, then there will be nothing in "result", not to > mention extracting information from the output. Thus it > seems to me the parent process has to wait till the child > process finish. > > > > So how to understand the meaning of "asynchronous"? > > "Asynchronous" means asynchronous - the parent is *not* > waiting. > > Which is the reason that there is (amongst other things) > the "wait"-method you can call to wait for the child to be > terminated. > > Diez > -- http://mail.python.org/mailman/listinfo/python-list > -- http://mail.python.org/mailman/listinfo/python-list
