Hi I have one stupid question. "man poll" describe this error code. >ERRORS > EBADF An invalid file descriptor was given in one of the sets. but current kernel implementation ignore invalid file descriptor, not return EBADF. ================ cut code ======================================== static inline unsigned int do_pollfd(struct pollfd *pollfd, poll_table *pwait) { unsigned int mask; int fd; mask = 0; fd = pollfd->fd; if (fd >= 0) { //// here int fput_needed; struct file * file; file = fget_light(fd, &fput_needed); mask = POLLNVAL; if (file != NULL) { //// and here mask = DEFAULT_POLLMASK; if (file->f_op && file->f_op->poll) mask = file->f_op->poll(file, pwait); /* Mask out unneeded events. */ mask &= pollfd->events | POLLERR | POLLHUP; fput_light(file, fput_needed); } } ================ end code ======================================== In the other hand, SUSv3 talk about > POLLNVAL > The specified fd value is invalid. This flag is only valid in the > revents member; it shall ignored in the events member. and > If the value of fd is less than 0, events shall be ignored, and revents > shall be set to 0 in that entry on return from poll(). but, no desribe EBADF. (see http://www.opengroup.org/onlinepubs/009695399/functions/poll.html) So, I think the implementation is correct. Why don't we remove EBADF description? -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html