Module Name: src
Committed By: elad
Date: Tue Sep 1 22:01:48 UTC 2009
Modified Files:
src/lib/libc/sys: kqueue.2
Log Message:
Add useful example program from
http://mail-index.netbsd.org/tech-kern/2009/09/01/msg006020.html
To generate a diff of this commit:
cvs rdiff -u -r1.22 -r1.23 src/lib/libc/sys/kqueue.2
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/lib/libc/sys/kqueue.2
diff -u src/lib/libc/sys/kqueue.2:1.22 src/lib/libc/sys/kqueue.2:1.23
--- src/lib/libc/sys/kqueue.2:1.22 Thu Mar 12 10:16:37 2009
+++ src/lib/libc/sys/kqueue.2 Tue Sep 1 22:01:48 2009
@@ -1,4 +1,4 @@
-.\" $NetBSD: kqueue.2,v 1.22 2009/03/12 10:16:37 wiz Exp $
+.\" $NetBSD: kqueue.2,v 1.23 2009/09/01 22:01:48 elad Exp $
.\"
.\" Copyright (c) 2000 Jonathan Lemon
.\" All rights reserved.
@@ -32,7 +32,7 @@
.\"
.\" $FreeBSD: src/lib/libc/sys/kqueue.2,v 1.22 2001/06/27 19:55:57 dd Exp $
.\"
-.Dd February 4, 2003
+.Dd September 1, 2009
.Dt KQUEUE 2
.Os
.Sh NAME
@@ -478,6 +478,76 @@
If the time limit expires, then
.Fn kevent
returns 0.
+.Sh EXAMPLES
+The following example program monitors a file (provided to it as the first
+argument) and prints information about some common events it receives
+notifications for:
+.Bd -literal -offset indent
+#include <sys/types.h>
+#include <sys/event.h>
+#include <sys/time.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <err.h>
+
+int
+main(int argc, char *argv[])
+{
+ int fd, kq, nev;
+ struct kevent ev, ch;
+ static const struct timespec tout = { 1, 0 };
+
+ if ((fd = open(argv[1], O_RDONLY)) == -1)
+ err(1, "Cannot open `%s'", argv[1]);
+
+ if ((kq = kqueue()) == -1)
+ err(1, "Cannot create kqueue");
+
+ EV_SET(&ch, fd, EVFILT_VNODE, EV_ADD | EV_ENABLE | EV_CLEAR,
+ NOTE_DELETE|NOTE_WRITE|NOTE_EXTEND|NOTE_ATTRIB|NOTE_LINK|
+ NOTE_RENAME|NOTE_REVOKE, 0, 0);
+ for (;;) {
+ nev = kevent(kq, &ch, 1, &ev, 1, &tout);
+ if (nev == -1)
+ err(1, "kevent");
+ if (nev == 0)
+ continue;
+ if (ev.fflags & NOTE_DELETE) {
+ printf("deleted ");
+ ev.fflags &= ~NOTE_DELETE;
+ }
+ if (ev.fflags & NOTE_WRITE) {
+ printf("written ");
+ ev.fflags &= ~NOTE_WRITE;
+ }
+ if (ev.fflags & NOTE_EXTEND) {
+ printf("extended ");
+ ev.fflags &= ~NOTE_EXTEND;
+ }
+ if (ev.fflags & NOTE_ATTRIB) {
+ printf("chmod/chown ");
+ ev.fflags &= ~NOTE_ATTRIB;
+ }
+ if (ev.fflags & NOTE_LINK) {
+ printf("hardlinked ");
+ ev.fflags &= ~NOTE_LINK;
+ }
+ if (ev.fflags & NOTE_RENAME) {
+ printf("renamed ");
+ ev.fflags &= ~NOTE_RENAME;
+ }
+ if (ev.fflags & NOTE_REVOKE) {
+ printf("revoked ");
+ ev.fflags &= ~NOTE_REVOKE;
+ }
+ printf("\\n");
+ if (ev.fflags)
+ warnx("unknown event 0x%x\\n", ev.fflags);
+ }
+}
+.Ed
.Sh ERRORS
The
.Fn kqueue
