1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
|
<?xml version="1.0" encoding="utf-8"?>
<!-- $Revision$ -->
<chapter xml:id="ev.watcher-callbacks" xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink">
<title>Watcher callbacks</title>
<para>
All watchers can be active(waiting for events) or inactive(paused). Only
active watchers will have their callbacks invoked. All callbacks will be
called with at least two arguments:
<parameter>watcher</parameter>
- the watcher, and
<parameter>revents</parameter>
a bitmask of received events.
</para>
<para>
Watcher callbacks are passed to the watcher constructors (the classes derived
from
<classname>EvWatcher</classname>
-
<methodname>EvCheck::__construct</methodname>
,
<methodname>EvChild::__construct</methodname>
etc.). A watcher callback should match the following prototype:
</para>
<methodsynopsis>
<type>void</type>
<methodname>callback</methodname>
<methodparam
choice="opt">
<type>object</type>
<parameter>watcher</parameter>
<initializer>NULL</initializer>
</methodparam>
<methodparam
choice="opt">
<type>int</type>
<parameter>revents</parameter>
<initializer>NULL</initializer>
</methodparam>
</methodsynopsis>
<para>
<variablelist>
<varlistentry>
<term>
<parameter>watcher</parameter>
</term>
<listitem>
<para>
The watcher instance(of a class extending
<classname>EvWatcher</classname>
).
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<parameter>revents</parameter>
</term>
<listitem>
<para>
<link linkend="ev.constants.watcher-revents">Watcher received events</link>
.
</para>
</listitem>
</varlistentry>
</variablelist>
</para>
<para>
Each watcher type has its associated bit in
<parameter>revents</parameter>
, so one can use the same callback for multiple watchers. The event mask is
named after the type, i.e.
<classname>EvChild</classname>
(or
<methodname>EvLoop::child</methodname>
) sets
<constant>EV::CHILD</constant>
,
<classname>EvPrepare</classname>
(or
<methodname>EvLoop::prepare</methodname>
) sets
<constant>Ev::PREPARE</constant>
,
<classname>EvPeriodic</classname>
(or
<methodname>EvLoop::periodic</methodname>
) sets
<constant>Ev::PERIODIC</constant>
and so on, with the exception of I/O events (which can set both
<constant>Ev::READ</constant>
and
<constant>Ev::WRITE</constant>
bits).
</para>
</chapter>
<!-- Keep this comment at the end of the file
Local variables:
mode: sgml
sgml-omittag:t
sgml-shorttag:t
sgml-minimize-attributes:nil
sgml-always-quote-attributes:t
sgml-indent-step:1
sgml-indent-data:t
indent-tabs-mode:nil
sgml-parent-document:nil
sgml-default-dtd-file:"~/.phpdoc/manual.ced"
sgml-exposed-tags:nil
sgml-local-catalogs:nil
sgml-local-ecat-files:nil
End:
vim600: syn=xml fen fdm=syntax fdl=2 si
vim: et tw=78 syn=sgml
vi: ts=1 sw=1
-->
|
