Guido van Rossum added the comment: > > Why not simply reverse the wait() and read() calls? > > I don't think it is sufficient if the user uses more than one pipe. The > subprocess.communicate() and _communicate() methods are using threads > (Windows) or select (Unix) when multiple pipes for stdin, stderr and > stderr are involved.
That is done precisely to *avoid* blocking. I believe the only reason your example blocks is because you wait before reading -- you should do it the other way around, do all I/O first and *then* wait for the process to exit. > The only safe way with multiple pipes is communicate([input]) unless the > process returns *lots* of data. The subprocess module is buffering the > data in memory if the user uses PIPE or STDIN. I disagree. I don't believe it will block unless you make the mistake of waiting for the process first. > The subprocess module also contains a XXX comment in the unix version of > _communicate() > > # XXX Rewrite these to use non-blocking I/O on the > # file objects; they are no longer using C stdio! > > Should I create another bug entry for it? No, we have too many bug entries already. __________________________________ Tracker <[EMAIL PROTECTED]> <http://bugs.python.org/issue1606> __________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
