Re: [PATCH v5 4/5] docs: counter: Document character device interface

Pavel Machek
2020-10-08T08:10:48Z

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Hi!

> + int main(void)
> + {
> + struct pollfd pfd = { .events = POLLIN };
> + struct counter_event event_data[2];
> +
> + pfd.fd = open("/dev/counter0", O_RDWR);
> +
> + ioctl(pfd.fd, COUNTER_SET_WATCH_IOCTL, watches);
> + ioctl(pfd.fd, COUNTER_SET_WATCH_IOCTL, watches + 1);
> + ioctl(pfd.fd, COUNTER_LOAD_WATCHES_IOCTL);
> +
> + for (;;) {
> + poll(&pfd, 1, -1);

Why do poll, when you are doing blocking read?

> + read(pfd.fd, event_data, sizeof(event_data));

Does your new chrdev always guarantee returning complete buffer?

If so, should it behave like that?

Best regards,
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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