On 01/20/2015 11:40 PM, Andy Lutomirski wrote: > On Tue, Jan 20, 2015 at 1:57 AM, Fam Zheng <f...@redhat.com> wrote: >> This adds a new system call, epoll_mod_wait. It's described as below:
[...] >> There is no guartantee that all the commands are executed in order. >> Only >> if all the commands are successfully executed (all the error fields >> are >> set to 0), events are polled. > > If this doesn't happen, what error is returned? If I read the code correctly: the error of the first epoll_ctl op that fails. [...] >> RETURN VALUE >> >> When any error occurs, epoll_mod_wait() returns -1 and errno is set >> appropriately. All the "error" fields in cmds are unchanged before >> they >> are executed, and if any cmds are executed, the "error" fields are set >> to a return code accordingly. See also epoll_ctl for more details of >> the >> return code. > > Does this mean that callers should initialize the error fields to an > impossible value first so they can tell which commands were executed? Yes. (Ugly!) [...] >> ERRORS >> >> These errors apply on either the return value of epoll_mod_wait or >> error >> status for each command, respectively. > > Please clarify which errors are returned overall and which are per-command. Yes, I think this would be valuable as well. Thanks, Michael -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
