En Fri, 02 Mar 2007 14:38:59 -0300, Donn Cave <[EMAIL PROTECTED]> escribió:
> In article <[EMAIL PROTECTED]>, > "Gabriel Genellina" <[EMAIL PROTECTED]> wrote: > >> On http://docs.python.org/lib/popen2-flow-control.html there are some >> notes on possible flow control problems you may encounter. > > It's a nice summary of one problem, a deadlock due to full pipe > buffer when reading from two pipes. The proposed simple solution > depends too much on the cooperation of the child process to be > very interesting, though. The good news is that there is a real > solution and it isn't terribly complex, you just have to use select() > and UNIX file descriptor I/O. The bad news is that while this is > a real problem, it isn't the one commonly encountered by first > time users of popen. More bad news: you can't use select() with file handles on Windows. >> If you have no control over the child process, it may be safer to use a >> different thread for reading its output. > > Right - `I used threads to solve my problem, and now I have two > problems.' It can work for some variations on this problem, but > not the majority of them. Any pointers on what kind of problems may happen, and usual solutions for them? On Windows one could use asynchronous I/O, or I/O completion ports, but neither of these are available directly from Python. So using a separate thread for reading may be the only solution, and I can't see why is it so bad. (Apart from buffering on the child process, which you can't control anyway). -- Gabriel Genellina -- http://mail.python.org/mailman/listinfo/python-list
