Charles-François Natali <neolo...@free.fr> added the comment: Hello Idan,
> The following program hangs on Debian Debian is a good choice :-) Concerning your example, it hangs is because the file descriptor used to communicate with proc1 is inherited when proc2 is created (FDs are inherited upon fork by default): thus, when you call proc1.stdin.close(), `cat` doesn't receive EOF on read(0), and remains stuck. If you close proc2's stdin and wait it first, then you don't have this problem: - because it's been created after proc1, its stdin FD has not been inherited - when you call proc2.stdin.close(), `cat` receives EOF from read(0), and exits There are two reasons while it doesn't hang on Python 3.x: 1) it uses close_fds=True by default 2) it sets the pipe FDs CLOEXEC, so that they're closed when cat is `executed` Try with """ proc1 = subprocess.Popen(['cat'], stdin=subprocess.PIPE) proc2 = subprocess.Popen(['cat'], stdin=subprocess.PIPE, close_fds=True) proc1.stdin.close() proc1.wait() """ And you'll be fine. We can't make the change 1) in 2.7, because that's a behavior change. We could however set the FDs used to communicate with the children CLOEXEC. I'll work on a patch for 2.7 (but it won't be thread-safe, because pipe2 is not exposed and there's no _posixsubprocess.c like in 3.x). ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue12786> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
