On Fri, 2007-03-09 at 15:41 -0800, Davide Libenzi wrote: > This patch introduces a new system call for timers events delivered > though file descriptors. This allows timer event to be used with > standard POSIX poll(2), select(2) and read(2). As a consequence of > supporting the Linux f_op->poll subsystem, they can be used with > epoll(2) too. > The system call is defined as: > > int timerfd(int ufd, int tmrtype, const struct timespec *utmr); > > The "ufd" parameter allows for re-use (re-programming) of an existing > timerfd w/out going through the close/open cycle (same as signalfd). > If "ufd" is -1, s new file descriptor will be created, otherwise the > existing "ufd" will be re-programmed. > The "tmrtype" parameter allows to specify the timer type. The following > values are supported: > > TFD_TIMER_REL > The time specified in the "utmr" parameter is a relative time > from NOW. > > TFD_TIMER_ABS > The timer specified in the "utmr" parameter is an absolute time. > > TFD_TIMER_SEQ > The time specified in the "utmr" parameter is an interval at > which a continuous clock rate will be generated. > > The function returns the new (or same, in case "ufd" is a valid timerfd > descriptor) file, or -1 in case of error. > As stated before, the timerfd file descriptor supports poll(2), select(2) > and epoll(2). When a timer event happened on the timerfd, a POLLIN mask > will be returned. > The read(2) call can be used, and it will return a u32 variable holding > the number of "ticks" that happened on the interface since the last call > to read(2). The read(2) call supportes the O_NONBLOCK flag too, and EAGAIN > will be returned if no ticks happened. > A quick test program, shows timerfd working correctly on my amd64 box: > > http://www.xmailserver.org/timerfd-test.c >
Why did you ignore the existing POSIX timer API? -- Nicholas Miell <[EMAIL PROTECTED]> - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
