Charles-François Natali added the comment: >> there's no SELECT_ERR anymore [...] the error will be reported when the FD >> will be read/written > > I don't think this is a good idea, particularly during this early stage. > This assumption might be valid for select() but not for poll() and epoll() > where (POLLERR | POLLHUP | POLLNVAL) is an alias for "connection lost", and > that's an event which both Twisted and Tornado take into account and treat > differently than a pure "read" event.
POLLERR and POLLNVAL semantics can be really different from "connection lost", so this mapping sounds wrong. The actual error (which may be ECONNRESET, but also EBADF, ENOBUFS...) will be raised upon the next call to read()/write(), or can be retrieved through getsockopt(SO_ERROR). Also, that's exactly what the Linux kernel does for select(): http://lxr.free-electrons.com/source/fs/select.c#L381 POLLHUP is mapped to the read-set, POLLERR both to the read and write set. This means that "connection lost" could never be returned on platforms where the select() syscall is used, which could lead to subtle portability problems. But I'm definitely open on this (I've based the behavior on libevent and Java, FWIW). >> the exceptions set isn't passed to select() anymore: exception events (like >> OOB) are already reported in the read or write sets > > That's true only if SO_OOBINLINE has been pre-emptively set against the > socket. > It might be ok to ignore select()'s exceptional events anyway though. Thanks, I didn't know: since the POSIX man pages was rather evasive on this, I checked the Linux kernel source code, but apparently it's non-standard. If we do ignore OOB in select(), then we probably also want to suppress POLLPRI|EPOLLPRI, no? ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue16853> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
