Author: bcr (doc committer) Date: Sun May 1 18:09:34 2016 New Revision: 298893 URL: https://svnweb.freebsd.org/changeset/base/298893
Log: Provide an example to the kqueue man page, showing a basic usage example. Although it is an untypical example for the use of kqueue, it is better than nothing and should get people started. PR: 196844 Submitted by: fernando.apesteg...@gmail.com Reviewed by: kib Approved by: kib MFC after: 5 days Differential Revision: https://reviews.freebsd.org/D6082 Modified: head/lib/libc/sys/kqueue.2 Modified: head/lib/libc/sys/kqueue.2 ============================================================================== --- head/lib/libc/sys/kqueue.2 Sun May 1 17:55:45 2016 (r298892) +++ head/lib/libc/sys/kqueue.2 Sun May 1 18:09:34 2016 (r298893) @@ -24,7 +24,7 @@ .\" .\" $FreeBSD$ .\" -.Dd August 4, 2015 +.Dd May 1, 2016 .Dt KQUEUE 2 .Os .Sh NAME @@ -603,6 +603,57 @@ will be set to indicate the error condit If the time limit expires, then .Fn kevent returns 0. +.Sh EXAMPLES +.Bd -literal -compact +#include <sys/types.h> +#include <sys/event.h> +#include <sys/time.h> +#include <err.h> +#include <fcntl.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> + +int +main(int argc, char **argv) +{ + struct kevent event; /* Event we want to monitor */ + struct kevent tevent; /* Event triggered */ + int kq, fd, ret; + + if (argc != 2) + err(EXIT_FAILURE, "Usage: %s path\en", argv[0]); + fd = open(argv[1], O_RDONLY); + if (fd == -1) + err(EXIT_FAILURE, "Failed to open '%s'", argv[1]); + + /* Create kqueue. */ + kq = kqueue(); + if (kq == -1) + err(EXIT_FAILURE, "kqueue() failed"); + + /* Initialize kevent structure. */ + EV_SET(&event, fd, EVFILT_VNODE, EV_ADD | EV_CLEAR, NOTE_WRITE, + 0, NULL); + /* Attach event to the kqueue. */ + ret = kevent(kq, &event, 1, NULL, 0, NULL); + if (ret == -1) + err(EXIT_FAILURE, "kevent register"); + if (event.flags & EV_ERROR) + errx(EXIT_FAILURE, "Event error: %s", strerror(event.data)); + + for (;;) { + /* Sleep until something happens. */ + ret = kevent(kq, NULL, 0, &tevent, 1, NULL); + if (ret == -1) { + err(EXIT_FAILURE, "kevent wait"); + } else if (ret > 0) { + printf("Something was written in '%s'\en", argv[1]); + } + } +} +.Ed .Sh ERRORS The .Fn kqueue _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
