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Marc Alexander Lehmann 16 years ago
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24
ev.3
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@ -129,7 +129,7 @@
.\" ========================================================================
.\"
.IX Title ""<STANDARD INPUT>" 1"
.TH "<STANDARD INPUT>" 1 "2007-12-09" "perl v5.8.8" "User Contributed Perl Documentation"
.TH "<STANDARD INPUT>" 1 "2007-12-12" "perl v5.8.8" "User Contributed Perl Documentation"
.SH "NAME"
libev \- a high performance full\-featured event loop written in C
.SH "SYNOPSIS"
@ -1067,6 +1067,28 @@ play around with an Xlib connection), then you have to seperately re-test
whether a file descriptor is really ready with a known-to-be good interface
such as poll (fortunately in our Xlib example, Xlib already does this on
its own, so its quite safe to use).
.PP
\fIThe special problem of disappearing file descriptors\fR
.IX Subsection "The special problem of disappearing file descriptors"
.PP
Some backends (e.g kqueue, epoll) need to be told about closing a file
descriptor (either by calling \f(CW\*(C`close\*(C'\fR explicitly or by any other means,
such as \f(CW\*(C`dup\*(C'\fR). The reason is that you register interest in some file
descriptor, but when it goes away, the operating system will silently drop
this interest. If another file descriptor with the same number then is
registered with libev, there is no efficient way to see that this is, in
fact, a different file descriptor.
.PP
To avoid having to explicitly tell libev about such cases, libev follows
the following policy: Each time \f(CW\*(C`ev_io_set\*(C'\fR is being called, libev
will assume that this is potentially a new file descriptor, otherwise
it is assumed that the file descriptor stays the same. That means that
you \fIhave\fR to call \f(CW\*(C`ev_io_set\*(C'\fR (or \f(CW\*(C`ev_io_init\*(C'\fR) when you change the
descriptor even if the file descriptor number itself did not change.
.PP
This is how one would do it normally anyway, the important point is that
the libev application should not optimise around libev but should leave
optimisations to libev.
.IP "ev_io_init (ev_io *, callback, int fd, int events)" 4
.IX Item "ev_io_init (ev_io *, callback, int fd, int events)"
.PD 0

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ev.html
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@ -6,7 +6,7 @@
<meta name="description" content="Pod documentation for libev" />
<meta name="inputfile" content="&lt;standard input&gt;" />
<meta name="outputfile" content="&lt;standard output&gt;" />
<meta name="created" content="Sun Dec 9 20:47:27 2007" />
<meta name="created" content="Wed Dec 12 05:53:55 2007" />
<meta name="generator" content="Pod::Xhtml 1.57" />
<link rel="stylesheet" href="http://res.tst.eu/pod.css"/></head>
<body>
@ -29,7 +29,10 @@
</ul>
</li>
<li><a href="#WATCHER_TYPES">WATCHER TYPES</a>
<ul><li><a href="#code_ev_io_code_is_this_file_descrip"><code>ev_io</code> - is this file descriptor readable or writable?</a></li>
<ul><li><a href="#code_ev_io_code_is_this_file_descrip"><code>ev_io</code> - is this file descriptor readable or writable?</a>
<ul><li><a href="#The_special_problem_of_disappearing_">The special problem of disappearing file descriptors</a></li>
</ul>
</li>
<li><a href="#code_ev_timer_code_relative_and_opti"><code>ev_timer</code> - relative and optionally repeating timeouts</a></li>
<li><a href="#code_ev_periodic_code_to_cron_or_not"><code>ev_periodic</code> - to cron or not to cron?</a></li>
<li><a href="#code_ev_signal_code_signal_me_when_a"><code>ev_signal</code> - signal me when a signal gets signalled!</a></li>
@ -943,6 +946,30 @@ play around with an Xlib connection), then you have to seperately re-test
whether a file descriptor is really ready with a known-to-be good interface
such as poll (fortunately in our Xlib example, Xlib already does this on
its own, so its quite safe to use).</p>
</div>
<h3 id="The_special_problem_of_disappearing_">The special problem of disappearing file descriptors</h3>
<div id="The_special_problem_of_disappearing_-2">
<p>Some backends (e.g kqueue, epoll) need to be told about closing a file
descriptor (either by calling <code>close</code> explicitly or by any other means,
such as <code>dup</code>). The reason is that you register interest in some file
descriptor, but when it goes away, the operating system will silently drop
this interest. If another file descriptor with the same number then is
registered with libev, there is no efficient way to see that this is, in
fact, a different file descriptor.</p>
<p>To avoid having to explicitly tell libev about such cases, libev follows
the following policy: Each time <code>ev_io_set</code> is being called, libev
will assume that this is potentially a new file descriptor, otherwise
it is assumed that the file descriptor stays the same. That means that
you <i>have</i> to call <code>ev_io_set</code> (or <code>ev_io_init</code>) when you change the
descriptor even if the file descriptor number itself did not change.</p>
<p>This is how one would do it normally anyway, the important point is that
the libev application should not optimise around libev but should leave
optimisations to libev.</p>
<dl>
<dt>ev_io_init (ev_io *, callback, int fd, int events)</dt>
<dt>ev_io_set (ev_io *, int fd, int events)</dt>

22
ev.pod
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@ -913,6 +913,28 @@ whether a file descriptor is really ready with a known-to-be good interface
such as poll (fortunately in our Xlib example, Xlib already does this on
its own, so its quite safe to use).
=head3 The special problem of disappearing file descriptors
Some backends (e.g kqueue, epoll) need to be told about closing a file
descriptor (either by calling C<close> explicitly or by any other means,
such as C<dup>). The reason is that you register interest in some file
descriptor, but when it goes away, the operating system will silently drop
this interest. If another file descriptor with the same number then is
registered with libev, there is no efficient way to see that this is, in
fact, a different file descriptor.
To avoid having to explicitly tell libev about such cases, libev follows
the following policy: Each time C<ev_io_set> is being called, libev
will assume that this is potentially a new file descriptor, otherwise
it is assumed that the file descriptor stays the same. That means that
you I<have> to call C<ev_io_set> (or C<ev_io_init>) when you change the
descriptor even if the file descriptor number itself did not change.
This is how one would do it normally anyway, the important point is that
the libev application should not optimise around libev but should leave
optimisations to libev.
=over 4
=item ev_io_init (ev_io *, callback, int fd, int events)

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