From owner-svn-src-all@freebsd.org Sun May 1 18:09:36 2016 Return-Path: Delivered-To: svn-src-all@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 0E024B29AA4; Sun, 1 May 2016 18:09:36 +0000 (UTC) (envelope-from bcr@FreeBSD.org) Received: from repo.freebsd.org (repo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id B24A51966; Sun, 1 May 2016 18:09:35 +0000 (UTC) (envelope-from bcr@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id u41I9YQr048467; Sun, 1 May 2016 18:09:34 GMT (envelope-from bcr@FreeBSD.org) Received: (from bcr@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id u41I9YsG048466; Sun, 1 May 2016 18:09:34 GMT (envelope-from bcr@FreeBSD.org) Message-Id: <201605011809.u41I9YsG048466@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: bcr set sender to bcr@FreeBSD.org using -f From: Benedict Reuschling Date: Sun, 1 May 2016 18:09:34 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r298893 - head/lib/libc/sys X-SVN-Group: head MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 01 May 2016 18:09:36 -0000 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.apesteguia@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 +#include +#include +#include +#include +#include +#include +#include +#include + +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