On Sun, Aug 18, 2019 at 12:36 AM Heiher <r@xxxxxx> wrote:
>
> Hello,
>
> I've added a pipe file descriptor (fd1) to an epoll (fd3) with
> EPOLLOUT in edge-triggered mode, and then added the fd3 to another
> epoll (fd4) with EPOLLIN in edge-triggered too.
>
> Next, waiting for fd4 without timeout. When fd1 to be writable, i
> think epoll_wait(fd4, ...) only return once, because all file
> descriptors are added in edge-triggered mode.
>
> But, the actual result is returns many and many times until do once
> eopll_wait(fd3, ...).
>
> #include <stdio.h>
> #include <unistd.h>
> #include <sys/epoll.h>
>
> int
> main (int argc, char *argv[])
> {
> int efd[2];
> struct epoll_event e;
>
> efd[0] = epoll_create (1);
> if (efd[0] < 0)
> return -1;
>
> efd[1] = epoll_create (1);
> if (efd[1] < 0)
> return -2;
>
> e.events = EPOLLIN | EPOLLET;
> e.data.u64 = 1;
> if (epoll_ctl (efd[0], EPOLL_CTL_ADD, efd[1], &e) < 0)
> return -3;
>
> e.events = EPOLLOUT | EPOLLET;
> e.data.u64 = 2;
> if (epoll_ctl (efd[1], EPOLL_CTL_ADD, 1, &e) < 0)
> return -4;
>
> for (;;) {
> struct epoll_event events[16];
> int nfds;
>
> nfds = epoll_wait (efd[0], events, 16, -1);
> printf ("nfds: %d\n", nfds);
> }
>
> close (efd[1]);
> close (efd[0]);
>
> return 0;
> }
>
> --
> Best regards!
> Hev
> https://hev.cc
Is this behavior correct? any help?
--
Best regards!
Hev
https://hev.cc
