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4 | <head> |
4 | <head> |
5 | <title>libev</title> |
5 | <title>libev</title> |
6 | <meta name="description" content="Pod documentation for libev" /> |
6 | <meta name="description" content="Pod documentation for libev" /> |
7 | <meta name="inputfile" content="<standard input>" /> |
7 | <meta name="inputfile" content="<standard input>" /> |
8 | <meta name="outputfile" content="<standard output>" /> |
8 | <meta name="outputfile" content="<standard output>" /> |
9 | <meta name="created" content="Sat Nov 24 17:31:33 2007" /> |
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12 | <body> |
12 | <body> |
13 | <div class="pod"> |
13 | <div class="pod"> |
14 | <!-- INDEX START --> |
14 | <!-- INDEX START --> |
15 | <h3 id="TOP">Index</h3> |
15 | <h3 id="TOP">Index</h3> |
16 | |
16 | |
17 | <ul><li><a href="#NAME">NAME</a></li> |
17 | <ul><li><a href="#NAME">NAME</a></li> |
18 | <li><a href="#SYNOPSIS">SYNOPSIS</a></li> |
18 | <li><a href="#SYNOPSIS">SYNOPSIS</a></li> |
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19 | <li><a href="#EXAMPLE_PROGRAM">EXAMPLE PROGRAM</a></li> |
19 | <li><a href="#DESCRIPTION">DESCRIPTION</a></li> |
20 | <li><a href="#DESCRIPTION">DESCRIPTION</a></li> |
20 | <li><a href="#FEATURES">FEATURES</a></li> |
21 | <li><a href="#FEATURES">FEATURES</a></li> |
21 | <li><a href="#CONVENTIONS">CONVENTIONS</a></li> |
22 | <li><a href="#CONVENTIONS">CONVENTIONS</a></li> |
22 | <li><a href="#TIME_REPRESENTATION">TIME REPRESENTATION</a></li> |
23 | <li><a href="#TIME_REPRESENTATION">TIME REPRESENTATION</a></li> |
23 | <li><a href="#GLOBAL_FUNCTIONS">GLOBAL FUNCTIONS</a></li> |
24 | <li><a href="#GLOBAL_FUNCTIONS">GLOBAL FUNCTIONS</a></li> |
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31 | <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> |
32 | <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> |
32 | <li><a href="#code_ev_timer_code_relative_and_opti"><code>ev_timer</code> - relative and optionally repeating timeouts</a></li> |
33 | <li><a href="#code_ev_timer_code_relative_and_opti"><code>ev_timer</code> - relative and optionally repeating timeouts</a></li> |
33 | <li><a href="#code_ev_periodic_code_to_cron_or_not"><code>ev_periodic</code> - to cron or not to cron?</a></li> |
34 | <li><a href="#code_ev_periodic_code_to_cron_or_not"><code>ev_periodic</code> - to cron or not to cron?</a></li> |
34 | <li><a href="#code_ev_signal_code_signal_me_when_a"><code>ev_signal</code> - signal me when a signal gets signalled!</a></li> |
35 | <li><a href="#code_ev_signal_code_signal_me_when_a"><code>ev_signal</code> - signal me when a signal gets signalled!</a></li> |
35 | <li><a href="#code_ev_child_code_watch_out_for_pro"><code>ev_child</code> - watch out for process status changes</a></li> |
36 | <li><a href="#code_ev_child_code_watch_out_for_pro"><code>ev_child</code> - watch out for process status changes</a></li> |
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37 | <li><a href="#code_ev_stat_code_did_the_file_attri"><code>ev_stat</code> - did the file attributes just change?</a></li> |
36 | <li><a href="#code_ev_idle_code_when_you_ve_got_no"><code>ev_idle</code> - when you've got nothing better to do...</a></li> |
38 | <li><a href="#code_ev_idle_code_when_you_ve_got_no"><code>ev_idle</code> - when you've got nothing better to do...</a></li> |
37 | <li><a href="#code_ev_prepare_code_and_code_ev_che"><code>ev_prepare</code> and <code>ev_check</code> - customise your event loop!</a></li> |
39 | <li><a href="#code_ev_prepare_code_and_code_ev_che"><code>ev_prepare</code> and <code>ev_check</code> - customise your event loop!</a></li> |
38 | <li><a href="#code_ev_embed_code_when_one_backend_"><code>ev_embed</code> - when one backend isn't enough...</a></li> |
40 | <li><a href="#code_ev_embed_code_when_one_backend_"><code>ev_embed</code> - when one backend isn't enough...</a></li> |
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41 | <li><a href="#code_ev_fork_code_the_audacity_to_re"><code>ev_fork</code> - the audacity to resume the event loop after a fork</a></li> |
39 | </ul> |
42 | </ul> |
40 | </li> |
43 | </li> |
41 | <li><a href="#OTHER_FUNCTIONS">OTHER FUNCTIONS</a></li> |
44 | <li><a href="#OTHER_FUNCTIONS">OTHER FUNCTIONS</a></li> |
42 | <li><a href="#LIBEVENT_EMULATION">LIBEVENT EMULATION</a></li> |
45 | <li><a href="#LIBEVENT_EMULATION">LIBEVENT EMULATION</a></li> |
43 | <li><a href="#C_SUPPORT">C++ SUPPORT</a></li> |
46 | <li><a href="#C_SUPPORT">C++ SUPPORT</a></li> |
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47 | <li><a href="#MACRO_MAGIC">MACRO MAGIC</a></li> |
44 | <li><a href="#EMBEDDING">EMBEDDING</a> |
48 | <li><a href="#EMBEDDING">EMBEDDING</a> |
45 | <ul><li><a href="#FILESETS">FILESETS</a> |
49 | <ul><li><a href="#FILESETS">FILESETS</a> |
46 | <ul><li><a href="#CORE_EVENT_LOOP">CORE EVENT LOOP</a></li> |
50 | <ul><li><a href="#CORE_EVENT_LOOP">CORE EVENT LOOP</a></li> |
47 | <li><a href="#LIBEVENT_COMPATIBILITY_API">LIBEVENT COMPATIBILITY API</a></li> |
51 | <li><a href="#LIBEVENT_COMPATIBILITY_API">LIBEVENT COMPATIBILITY API</a></li> |
48 | <li><a href="#AUTOCONF_SUPPORT">AUTOCONF SUPPORT</a></li> |
52 | <li><a href="#AUTOCONF_SUPPORT">AUTOCONF SUPPORT</a></li> |
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50 | </li> |
54 | </li> |
51 | <li><a href="#PREPROCESSOR_SYMBOLS_MACROS">PREPROCESSOR SYMBOLS/MACROS</a></li> |
55 | <li><a href="#PREPROCESSOR_SYMBOLS_MACROS">PREPROCESSOR SYMBOLS/MACROS</a></li> |
52 | <li><a href="#EXAMPLES">EXAMPLES</a></li> |
56 | <li><a href="#EXAMPLES">EXAMPLES</a></li> |
53 | </ul> |
57 | </ul> |
54 | </li> |
58 | </li> |
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59 | <li><a href="#COMPLEXITIES">COMPLEXITIES</a></li> |
55 | <li><a href="#AUTHOR">AUTHOR</a> |
60 | <li><a href="#AUTHOR">AUTHOR</a> |
56 | </li> |
61 | </li> |
57 | </ul><hr /> |
62 | </ul><hr /> |
58 | <!-- INDEX END --> |
63 | <!-- INDEX END --> |
59 | |
64 | |
60 | <h1 id="NAME">NAME</h1><p><a href="#TOP" class="toplink">Top</a></p> |
65 | <h1 id="NAME">NAME</h1> |
61 | <div id="NAME_CONTENT"> |
66 | <div id="NAME_CONTENT"> |
62 | <p>libev - a high performance full-featured event loop written in C</p> |
67 | <p>libev - a high performance full-featured event loop written in C</p> |
63 | |
68 | |
64 | </div> |
69 | </div> |
65 | <h1 id="SYNOPSIS">SYNOPSIS</h1><p><a href="#TOP" class="toplink">Top</a></p> |
70 | <h1 id="SYNOPSIS">SYNOPSIS</h1> |
66 | <div id="SYNOPSIS_CONTENT"> |
71 | <div id="SYNOPSIS_CONTENT"> |
67 | <pre> #include <ev.h> |
72 | <pre> #include <ev.h> |
68 | |
73 | |
69 | </pre> |
74 | </pre> |
70 | |
75 | |
71 | </div> |
76 | </div> |
72 | <h1 id="DESCRIPTION">DESCRIPTION</h1><p><a href="#TOP" class="toplink">Top</a></p> |
77 | <h1 id="EXAMPLE_PROGRAM">EXAMPLE PROGRAM</h1> |
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78 | <div id="EXAMPLE_PROGRAM_CONTENT"> |
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79 | <pre> #include <ev.h> |
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80 | |
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81 | ev_io stdin_watcher; |
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82 | ev_timer timeout_watcher; |
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83 | |
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84 | /* called when data readable on stdin */ |
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85 | static void |
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86 | stdin_cb (EV_P_ struct ev_io *w, int revents) |
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87 | { |
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88 | /* puts ("stdin ready"); */ |
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89 | ev_io_stop (EV_A_ w); /* just a syntax example */ |
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90 | ev_unloop (EV_A_ EVUNLOOP_ALL); /* leave all loop calls */ |
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91 | } |
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92 | |
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93 | static void |
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94 | timeout_cb (EV_P_ struct ev_timer *w, int revents) |
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95 | { |
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96 | /* puts ("timeout"); */ |
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97 | ev_unloop (EV_A_ EVUNLOOP_ONE); /* leave one loop call */ |
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98 | } |
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99 | |
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100 | int |
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101 | main (void) |
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102 | { |
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103 | struct ev_loop *loop = ev_default_loop (0); |
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104 | |
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105 | /* initialise an io watcher, then start it */ |
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106 | ev_io_init (&stdin_watcher, stdin_cb, /*STDIN_FILENO*/ 0, EV_READ); |
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107 | ev_io_start (loop, &stdin_watcher); |
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108 | |
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109 | /* simple non-repeating 5.5 second timeout */ |
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110 | ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.); |
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111 | ev_timer_start (loop, &timeout_watcher); |
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112 | |
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113 | /* loop till timeout or data ready */ |
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114 | ev_loop (loop, 0); |
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115 | |
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116 | return 0; |
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117 | } |
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118 | |
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119 | </pre> |
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120 | |
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121 | </div> |
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122 | <h1 id="DESCRIPTION">DESCRIPTION</h1> |
73 | <div id="DESCRIPTION_CONTENT"> |
123 | <div id="DESCRIPTION_CONTENT"> |
74 | <p>Libev is an event loop: you register interest in certain events (such as a |
124 | <p>Libev is an event loop: you register interest in certain events (such as a |
75 | file descriptor being readable or a timeout occuring), and it will manage |
125 | file descriptor being readable or a timeout occuring), and it will manage |
76 | these event sources and provide your program with events.</p> |
126 | these event sources and provide your program with events.</p> |
77 | <p>To do this, it must take more or less complete control over your process |
127 | <p>To do this, it must take more or less complete control over your process |
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81 | watchers</i>, which are relatively small C structures you initialise with the |
131 | watchers</i>, which are relatively small C structures you initialise with the |
82 | details of the event, and then hand it over to libev by <i>starting</i> the |
132 | details of the event, and then hand it over to libev by <i>starting</i> the |
83 | watcher.</p> |
133 | watcher.</p> |
84 | |
134 | |
85 | </div> |
135 | </div> |
86 | <h1 id="FEATURES">FEATURES</h1><p><a href="#TOP" class="toplink">Top</a></p> |
136 | <h1 id="FEATURES">FEATURES</h1> |
87 | <div id="FEATURES_CONTENT"> |
137 | <div id="FEATURES_CONTENT"> |
88 | <p>Libev supports select, poll, the linux-specific epoll and the bsd-specific |
138 | <p>Libev supports <code>select</code>, <code>poll</code>, the linux-specific <code>epoll</code>, the |
89 | kqueue mechanisms for file descriptor events, relative timers, absolute |
139 | bsd-specific <code>kqueue</code> and the solaris-specific event port mechanisms |
90 | timers with customised rescheduling, signal events, process status change |
140 | for file descriptor events (<code>ev_io</code>), relative timers (<code>ev_timer</code>), |
91 | events (related to SIGCHLD), and event watchers dealing with the event |
141 | absolute timers with customised rescheduling (<code>ev_periodic</code>), synchronous |
92 | loop mechanism itself (idle, prepare and check watchers). It also is quite |
142 | signals (<code>ev_signal</code>), process status change events (<code>ev_child</code>), and |
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143 | event watchers dealing with the event loop mechanism itself (<code>ev_idle</code>, |
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144 | <code>ev_embed</code>, <code>ev_prepare</code> and <code>ev_check</code> watchers) as well as |
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145 | file watchers (<code>ev_stat</code>) and even limited support for fork events |
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146 | (<code>ev_fork</code>).</p> |
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147 | <p>It also is quite fast (see this |
93 | fast (see this <a href="http://libev.schmorp.de/bench.html">benchmark</a> comparing |
148 | <a href="http://libev.schmorp.de/bench.html">benchmark</a> comparing it to libevent |
94 | it to libevent for example).</p> |
149 | for example).</p> |
95 | |
150 | |
96 | </div> |
151 | </div> |
97 | <h1 id="CONVENTIONS">CONVENTIONS</h1><p><a href="#TOP" class="toplink">Top</a></p> |
152 | <h1 id="CONVENTIONS">CONVENTIONS</h1> |
98 | <div id="CONVENTIONS_CONTENT"> |
153 | <div id="CONVENTIONS_CONTENT"> |
99 | <p>Libev is very configurable. In this manual the default configuration |
154 | <p>Libev is very configurable. In this manual the default configuration will |
100 | will be described, which supports multiple event loops. For more info |
155 | be described, which supports multiple event loops. For more info about |
101 | about various configuration options please have a look at the file |
156 | various configuration options please have a look at <strong>EMBED</strong> section in |
102 | <cite>README.embed</cite> in the libev distribution. If libev was configured without |
157 | this manual. If libev was configured without support for multiple event |
103 | support for multiple event loops, then all functions taking an initial |
158 | loops, then all functions taking an initial argument of name <code>loop</code> |
104 | argument of name <code>loop</code> (which is always of type <code>struct ev_loop *</code>) |
159 | (which is always of type <code>struct ev_loop *</code>) will not have this argument.</p> |
105 | will not have this argument.</p> |
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106 | |
160 | |
107 | </div> |
161 | </div> |
108 | <h1 id="TIME_REPRESENTATION">TIME REPRESENTATION</h1><p><a href="#TOP" class="toplink">Top</a></p> |
162 | <h1 id="TIME_REPRESENTATION">TIME REPRESENTATION</h1> |
109 | <div id="TIME_REPRESENTATION_CONTENT"> |
163 | <div id="TIME_REPRESENTATION_CONTENT"> |
110 | <p>Libev represents time as a single floating point number, representing the |
164 | <p>Libev represents time as a single floating point number, representing the |
111 | (fractional) number of seconds since the (POSIX) epoch (somewhere near |
165 | (fractional) number of seconds since the (POSIX) epoch (somewhere near |
112 | the beginning of 1970, details are complicated, don't ask). This type is |
166 | the beginning of 1970, details are complicated, don't ask). This type is |
113 | called <code>ev_tstamp</code>, which is what you should use too. It usually aliases |
167 | called <code>ev_tstamp</code>, which is what you should use too. It usually aliases |
114 | to the <code>double</code> type in C, and when you need to do any calculations on |
168 | to the <code>double</code> type in C, and when you need to do any calculations on |
115 | it, you should treat it as such.</p> |
169 | it, you should treat it as such.</p> |
116 | |
170 | |
117 | |
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118 | |
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119 | |
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120 | |
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121 | </div> |
171 | </div> |
122 | <h1 id="GLOBAL_FUNCTIONS">GLOBAL FUNCTIONS</h1><p><a href="#TOP" class="toplink">Top</a></p> |
172 | <h1 id="GLOBAL_FUNCTIONS">GLOBAL FUNCTIONS</h1> |
123 | <div id="GLOBAL_FUNCTIONS_CONTENT"> |
173 | <div id="GLOBAL_FUNCTIONS_CONTENT"> |
124 | <p>These functions can be called anytime, even before initialising the |
174 | <p>These functions can be called anytime, even before initialising the |
125 | library in any way.</p> |
175 | library in any way.</p> |
126 | <dl> |
176 | <dl> |
127 | <dt>ev_tstamp ev_time ()</dt> |
177 | <dt>ev_tstamp ev_time ()</dt> |
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140 | version of the library your program was compiled against.</p> |
190 | version of the library your program was compiled against.</p> |
141 | <p>Usually, it's a good idea to terminate if the major versions mismatch, |
191 | <p>Usually, it's a good idea to terminate if the major versions mismatch, |
142 | as this indicates an incompatible change. Minor versions are usually |
192 | as this indicates an incompatible change. Minor versions are usually |
143 | compatible to older versions, so a larger minor version alone is usually |
193 | compatible to older versions, so a larger minor version alone is usually |
144 | not a problem.</p> |
194 | not a problem.</p> |
145 | <p>Example: make sure we haven't accidentally been linked against the wrong |
195 | <p>Example: Make sure we haven't accidentally been linked against the wrong |
146 | version:</p> |
196 | version.</p> |
147 | <pre> assert (("libev version mismatch", |
197 | <pre> assert (("libev version mismatch", |
148 | ev_version_major () == EV_VERSION_MAJOR |
198 | ev_version_major () == EV_VERSION_MAJOR |
149 | && ev_version_minor () >= EV_VERSION_MINOR)); |
199 | && ev_version_minor () >= EV_VERSION_MINOR)); |
150 | |
200 | |
151 | </pre> |
201 | </pre> |
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179 | might be supported on the current system, you would need to look at |
229 | might be supported on the current system, you would need to look at |
180 | <code>ev_embeddable_backends () & ev_supported_backends ()</code>, likewise for |
230 | <code>ev_embeddable_backends () & ev_supported_backends ()</code>, likewise for |
181 | recommended ones.</p> |
231 | recommended ones.</p> |
182 | <p>See the description of <code>ev_embed</code> watchers for more info.</p> |
232 | <p>See the description of <code>ev_embed</code> watchers for more info.</p> |
183 | </dd> |
233 | </dd> |
184 | <dt>ev_set_allocator (void *(*cb)(void *ptr, long size))</dt> |
234 | <dt>ev_set_allocator (void *(*cb)(void *ptr, size_t size))</dt> |
185 | <dd> |
235 | <dd> |
186 | <p>Sets the allocation function to use (the prototype is similar to the |
236 | <p>Sets the allocation function to use (the prototype and semantics are |
187 | realloc C function, the semantics are identical). It is used to allocate |
237 | identical to the realloc C function). It is used to allocate and free |
188 | and free memory (no surprises here). If it returns zero when memory |
238 | memory (no surprises here). If it returns zero when memory needs to be |
189 | needs to be allocated, the library might abort or take some potentially |
239 | allocated, the library might abort or take some potentially destructive |
190 | destructive action. The default is your system realloc function.</p> |
240 | action. The default is your system realloc function.</p> |
191 | <p>You could override this function in high-availability programs to, say, |
241 | <p>You could override this function in high-availability programs to, say, |
192 | free some memory if it cannot allocate memory, to use a special allocator, |
242 | free some memory if it cannot allocate memory, to use a special allocator, |
193 | or even to sleep a while and retry until some memory is available.</p> |
243 | or even to sleep a while and retry until some memory is available.</p> |
194 | <p>Example: replace the libev allocator with one that waits a bit and then |
244 | <p>Example: Replace the libev allocator with one that waits a bit and then |
195 | retries: better than mine).</p> |
245 | retries).</p> |
196 | <pre> static void * |
246 | <pre> static void * |
197 | persistent_realloc (void *ptr, long size) |
247 | persistent_realloc (void *ptr, size_t size) |
198 | { |
248 | { |
199 | for (;;) |
249 | for (;;) |
200 | { |
250 | { |
201 | void *newptr = realloc (ptr, size); |
251 | void *newptr = realloc (ptr, size); |
202 | |
252 | |
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219 | indicating the system call or subsystem causing the problem. If this |
269 | indicating the system call or subsystem causing the problem. If this |
220 | callback is set, then libev will expect it to remedy the sitution, no |
270 | callback is set, then libev will expect it to remedy the sitution, no |
221 | matter what, when it returns. That is, libev will generally retry the |
271 | matter what, when it returns. That is, libev will generally retry the |
222 | requested operation, or, if the condition doesn't go away, do bad stuff |
272 | requested operation, or, if the condition doesn't go away, do bad stuff |
223 | (such as abort).</p> |
273 | (such as abort).</p> |
224 | <p>Example: do the same thing as libev does internally:</p> |
274 | <p>Example: This is basically the same thing that libev does internally, too.</p> |
225 | <pre> static void |
275 | <pre> static void |
226 | fatal_error (const char *msg) |
276 | fatal_error (const char *msg) |
227 | { |
277 | { |
228 | perror (msg); |
278 | perror (msg); |
229 | abort (); |
279 | abort (); |
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235 | </pre> |
285 | </pre> |
236 | </dd> |
286 | </dd> |
237 | </dl> |
287 | </dl> |
238 | |
288 | |
239 | </div> |
289 | </div> |
240 | <h1 id="FUNCTIONS_CONTROLLING_THE_EVENT_LOOP">FUNCTIONS CONTROLLING THE EVENT LOOP</h1><p><a href="#TOP" class="toplink">Top</a></p> |
290 | <h1 id="FUNCTIONS_CONTROLLING_THE_EVENT_LOOP">FUNCTIONS CONTROLLING THE EVENT LOOP</h1> |
241 | <div id="FUNCTIONS_CONTROLLING_THE_EVENT_LOOP-2"> |
291 | <div id="FUNCTIONS_CONTROLLING_THE_EVENT_LOOP-2"> |
242 | <p>An event loop is described by a <code>struct ev_loop *</code>. The library knows two |
292 | <p>An event loop is described by a <code>struct ev_loop *</code>. The library knows two |
243 | types of such loops, the <i>default</i> loop, which supports signals and child |
293 | types of such loops, the <i>default</i> loop, which supports signals and child |
244 | events, and dynamically created loops which do not.</p> |
294 | events, and dynamically created loops which do not.</p> |
245 | <p>If you use threads, a common model is to run the default event loop |
295 | <p>If you use threads, a common model is to run the default event loop |
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365 | <dd> |
415 | <dd> |
366 | <p>Similar to <code>ev_default_loop</code>, but always creates a new event loop that is |
416 | <p>Similar to <code>ev_default_loop</code>, but always creates a new event loop that is |
367 | always distinct from the default loop. Unlike the default loop, it cannot |
417 | always distinct from the default loop. Unlike the default loop, it cannot |
368 | handle signal and child watchers, and attempts to do so will be greeted by |
418 | handle signal and child watchers, and attempts to do so will be greeted by |
369 | undefined behaviour (or a failed assertion if assertions are enabled).</p> |
419 | undefined behaviour (or a failed assertion if assertions are enabled).</p> |
370 | <p>Example: try to create a event loop that uses epoll and nothing else.</p> |
420 | <p>Example: Try to create a event loop that uses epoll and nothing else.</p> |
371 | <pre> struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
421 | <pre> struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
372 | if (!epoller) |
422 | if (!epoller) |
373 | fatal ("no epoll found here, maybe it hides under your chair"); |
423 | fatal ("no epoll found here, maybe it hides under your chair"); |
374 | |
424 | |
375 | </pre> |
425 | </pre> |
… | |
… | |
468 | be handled here by queueing them when their watcher gets executed. |
518 | be handled here by queueing them when their watcher gets executed. |
469 | - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
519 | - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
470 | were used, return, otherwise continue with step *. |
520 | were used, return, otherwise continue with step *. |
471 | |
521 | |
472 | </pre> |
522 | </pre> |
473 | <p>Example: queue some jobs and then loop until no events are outsanding |
523 | <p>Example: Queue some jobs and then loop until no events are outsanding |
474 | anymore.</p> |
524 | anymore.</p> |
475 | <pre> ... queue jobs here, make sure they register event watchers as long |
525 | <pre> ... queue jobs here, make sure they register event watchers as long |
476 | ... as they still have work to do (even an idle watcher will do..) |
526 | ... as they still have work to do (even an idle watcher will do..) |
477 | ev_loop (my_loop, 0); |
527 | ev_loop (my_loop, 0); |
478 | ... jobs done. yeah! |
528 | ... jobs done. yeah! |
… | |
… | |
497 | example, libev itself uses this for its internal signal pipe: It is not |
547 | example, libev itself uses this for its internal signal pipe: It is not |
498 | visible to the libev user and should not keep <code>ev_loop</code> from exiting if |
548 | visible to the libev user and should not keep <code>ev_loop</code> from exiting if |
499 | no event watchers registered by it are active. It is also an excellent |
549 | no event watchers registered by it are active. It is also an excellent |
500 | way to do this for generic recurring timers or from within third-party |
550 | way to do this for generic recurring timers or from within third-party |
501 | libraries. Just remember to <i>unref after start</i> and <i>ref before stop</i>.</p> |
551 | libraries. Just remember to <i>unref after start</i> and <i>ref before stop</i>.</p> |
502 | <p>Example: create a signal watcher, but keep it from keeping <code>ev_loop</code> |
552 | <p>Example: Create a signal watcher, but keep it from keeping <code>ev_loop</code> |
503 | running when nothing else is active.</p> |
553 | running when nothing else is active.</p> |
504 | <pre> struct dv_signal exitsig; |
554 | <pre> struct ev_signal exitsig; |
505 | ev_signal_init (&exitsig, sig_cb, SIGINT); |
555 | ev_signal_init (&exitsig, sig_cb, SIGINT); |
506 | ev_signal_start (myloop, &exitsig); |
556 | ev_signal_start (loop, &exitsig); |
507 | evf_unref (myloop); |
557 | evf_unref (loop); |
508 | |
558 | |
509 | </pre> |
559 | </pre> |
510 | <p>Example: for some weird reason, unregister the above signal handler again.</p> |
560 | <p>Example: For some weird reason, unregister the above signal handler again.</p> |
511 | <pre> ev_ref (myloop); |
561 | <pre> ev_ref (loop); |
512 | ev_signal_stop (myloop, &exitsig); |
562 | ev_signal_stop (loop, &exitsig); |
513 | |
563 | |
514 | </pre> |
564 | </pre> |
515 | </dd> |
565 | </dd> |
516 | </dl> |
566 | </dl> |
517 | |
567 | |
518 | |
568 | |
519 | |
569 | |
520 | |
570 | |
521 | |
571 | |
522 | </div> |
572 | </div> |
523 | <h1 id="ANATOMY_OF_A_WATCHER">ANATOMY OF A WATCHER</h1><p><a href="#TOP" class="toplink">Top</a></p> |
573 | <h1 id="ANATOMY_OF_A_WATCHER">ANATOMY OF A WATCHER</h1> |
524 | <div id="ANATOMY_OF_A_WATCHER_CONTENT"> |
574 | <div id="ANATOMY_OF_A_WATCHER_CONTENT"> |
525 | <p>A watcher is a structure that you create and register to record your |
575 | <p>A watcher is a structure that you create and register to record your |
526 | interest in some event. For instance, if you want to wait for STDIN to |
576 | interest in some event. For instance, if you want to wait for STDIN to |
527 | become readable, you would create an <code>ev_io</code> watcher for that:</p> |
577 | become readable, you would create an <code>ev_io</code> watcher for that:</p> |
528 | <pre> static void my_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
578 | <pre> static void my_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
… | |
… | |
585 | </dd> |
635 | </dd> |
586 | <dt><code>EV_CHILD</code></dt> |
636 | <dt><code>EV_CHILD</code></dt> |
587 | <dd> |
637 | <dd> |
588 | <p>The pid specified in the <code>ev_child</code> watcher has received a status change.</p> |
638 | <p>The pid specified in the <code>ev_child</code> watcher has received a status change.</p> |
589 | </dd> |
639 | </dd> |
|
|
640 | <dt><code>EV_STAT</code></dt> |
|
|
641 | <dd> |
|
|
642 | <p>The path specified in the <code>ev_stat</code> watcher changed its attributes somehow.</p> |
|
|
643 | </dd> |
590 | <dt><code>EV_IDLE</code></dt> |
644 | <dt><code>EV_IDLE</code></dt> |
591 | <dd> |
645 | <dd> |
592 | <p>The <code>ev_idle</code> watcher has determined that you have nothing better to do.</p> |
646 | <p>The <code>ev_idle</code> watcher has determined that you have nothing better to do.</p> |
593 | </dd> |
647 | </dd> |
594 | <dt><code>EV_PREPARE</code></dt> |
648 | <dt><code>EV_PREPARE</code></dt> |
… | |
… | |
599 | <code>ev_loop</code> has gathered them, but before it invokes any callbacks for any |
653 | <code>ev_loop</code> has gathered them, but before it invokes any callbacks for any |
600 | received events. Callbacks of both watcher types can start and stop as |
654 | received events. Callbacks of both watcher types can start and stop as |
601 | many watchers as they want, and all of them will be taken into account |
655 | many watchers as they want, and all of them will be taken into account |
602 | (for example, a <code>ev_prepare</code> watcher might start an idle watcher to keep |
656 | (for example, a <code>ev_prepare</code> watcher might start an idle watcher to keep |
603 | <code>ev_loop</code> from blocking).</p> |
657 | <code>ev_loop</code> from blocking).</p> |
|
|
658 | </dd> |
|
|
659 | <dt><code>EV_EMBED</code></dt> |
|
|
660 | <dd> |
|
|
661 | <p>The embedded event loop specified in the <code>ev_embed</code> watcher needs attention.</p> |
|
|
662 | </dd> |
|
|
663 | <dt><code>EV_FORK</code></dt> |
|
|
664 | <dd> |
|
|
665 | <p>The event loop has been resumed in the child process after fork (see |
|
|
666 | <code>ev_fork</code>).</p> |
604 | </dd> |
667 | </dd> |
605 | <dt><code>EV_ERROR</code></dt> |
668 | <dt><code>EV_ERROR</code></dt> |
606 | <dd> |
669 | <dd> |
607 | <p>An unspecified error has occured, the watcher has been stopped. This might |
670 | <p>An unspecified error has occured, the watcher has been stopped. This might |
608 | happen because the watcher could not be properly started because libev |
671 | happen because the watcher could not be properly started because libev |
… | |
… | |
678 | events but its callback has not yet been invoked). As long as a watcher |
741 | events but its callback has not yet been invoked). As long as a watcher |
679 | is pending (but not active) you must not call an init function on it (but |
742 | is pending (but not active) you must not call an init function on it (but |
680 | <code>ev_TYPE_set</code> is safe) and you must make sure the watcher is available to |
743 | <code>ev_TYPE_set</code> is safe) and you must make sure the watcher is available to |
681 | libev (e.g. you cnanot <code>free ()</code> it).</p> |
744 | libev (e.g. you cnanot <code>free ()</code> it).</p> |
682 | </dd> |
745 | </dd> |
683 | <dt>callback = ev_cb (ev_TYPE *watcher)</dt> |
746 | <dt>callback ev_cb (ev_TYPE *watcher)</dt> |
684 | <dd> |
747 | <dd> |
685 | <p>Returns the callback currently set on the watcher.</p> |
748 | <p>Returns the callback currently set on the watcher.</p> |
686 | </dd> |
749 | </dd> |
687 | <dt>ev_cb_set (ev_TYPE *watcher, callback)</dt> |
750 | <dt>ev_cb_set (ev_TYPE *watcher, callback)</dt> |
688 | <dd> |
751 | <dd> |
… | |
… | |
720 | struct my_io *w = (struct my_io *)w_; |
783 | struct my_io *w = (struct my_io *)w_; |
721 | ... |
784 | ... |
722 | } |
785 | } |
723 | |
786 | |
724 | </pre> |
787 | </pre> |
725 | <p>More interesting and less C-conformant ways of catsing your callback type |
788 | <p>More interesting and less C-conformant ways of casting your callback type |
726 | have been omitted....</p> |
789 | instead have been omitted.</p> |
|
|
790 | <p>Another common scenario is having some data structure with multiple |
|
|
791 | watchers:</p> |
|
|
792 | <pre> struct my_biggy |
|
|
793 | { |
|
|
794 | int some_data; |
|
|
795 | ev_timer t1; |
|
|
796 | ev_timer t2; |
|
|
797 | } |
727 | |
798 | |
|
|
799 | </pre> |
|
|
800 | <p>In this case getting the pointer to <code>my_biggy</code> is a bit more complicated, |
|
|
801 | you need to use <code>offsetof</code>:</p> |
|
|
802 | <pre> #include <stddef.h> |
728 | |
803 | |
|
|
804 | static void |
|
|
805 | t1_cb (EV_P_ struct ev_timer *w, int revents) |
|
|
806 | { |
|
|
807 | struct my_biggy big = (struct my_biggy * |
|
|
808 | (((char *)w) - offsetof (struct my_biggy, t1)); |
|
|
809 | } |
729 | |
810 | |
|
|
811 | static void |
|
|
812 | t2_cb (EV_P_ struct ev_timer *w, int revents) |
|
|
813 | { |
|
|
814 | struct my_biggy big = (struct my_biggy * |
|
|
815 | (((char *)w) - offsetof (struct my_biggy, t2)); |
|
|
816 | } |
730 | |
817 | |
731 | |
818 | |
|
|
819 | |
|
|
820 | |
|
|
821 | </pre> |
|
|
822 | |
732 | </div> |
823 | </div> |
733 | <h1 id="WATCHER_TYPES">WATCHER TYPES</h1><p><a href="#TOP" class="toplink">Top</a></p> |
824 | <h1 id="WATCHER_TYPES">WATCHER TYPES</h1> |
734 | <div id="WATCHER_TYPES_CONTENT"> |
825 | <div id="WATCHER_TYPES_CONTENT"> |
735 | <p>This section describes each watcher in detail, but will not repeat |
826 | <p>This section describes each watcher in detail, but will not repeat |
736 | information given in the last section.</p> |
827 | information given in the last section. Any initialisation/set macros, |
|
|
828 | functions and members specific to the watcher type are explained.</p> |
|
|
829 | <p>Members are additionally marked with either <i>[read-only]</i>, meaning that, |
|
|
830 | while the watcher is active, you can look at the member and expect some |
|
|
831 | sensible content, but you must not modify it (you can modify it while the |
|
|
832 | watcher is stopped to your hearts content), or <i>[read-write]</i>, which |
|
|
833 | means you can expect it to have some sensible content while the watcher |
|
|
834 | is active, but you can also modify it. Modifying it may not do something |
|
|
835 | sensible or take immediate effect (or do anything at all), but libev will |
|
|
836 | not crash or malfunction in any way.</p> |
737 | |
837 | |
738 | |
838 | |
739 | |
839 | |
740 | |
840 | |
741 | |
841 | |
… | |
… | |
780 | <dd> |
880 | <dd> |
781 | <p>Configures an <code>ev_io</code> watcher. The <code>fd</code> is the file descriptor to |
881 | <p>Configures an <code>ev_io</code> watcher. The <code>fd</code> is the file descriptor to |
782 | rceeive events for and events is either <code>EV_READ</code>, <code>EV_WRITE</code> or |
882 | rceeive events for and events is either <code>EV_READ</code>, <code>EV_WRITE</code> or |
783 | <code>EV_READ | EV_WRITE</code> to receive the given events.</p> |
883 | <code>EV_READ | EV_WRITE</code> to receive the given events.</p> |
784 | </dd> |
884 | </dd> |
|
|
885 | <dt>int fd [read-only]</dt> |
|
|
886 | <dd> |
|
|
887 | <p>The file descriptor being watched.</p> |
|
|
888 | </dd> |
|
|
889 | <dt>int events [read-only]</dt> |
|
|
890 | <dd> |
|
|
891 | <p>The events being watched.</p> |
|
|
892 | </dd> |
785 | </dl> |
893 | </dl> |
786 | <p>Example: call <code>stdin_readable_cb</code> when STDIN_FILENO has become, well |
894 | <p>Example: Call <code>stdin_readable_cb</code> when STDIN_FILENO has become, well |
787 | readable, but only once. Since it is likely line-buffered, you could |
895 | readable, but only once. Since it is likely line-buffered, you could |
788 | attempt to read a whole line in the callback:</p> |
896 | attempt to read a whole line in the callback.</p> |
789 | <pre> static void |
897 | <pre> static void |
790 | stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
898 | stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
791 | { |
899 | { |
792 | ev_io_stop (loop, w); |
900 | ev_io_stop (loop, w); |
793 | .. read from stdin here (or from w->fd) and haqndle any I/O errors |
901 | .. read from stdin here (or from w->fd) and haqndle any I/O errors |
… | |
… | |
846 | repeating. The exact semantics are:</p> |
954 | repeating. The exact semantics are:</p> |
847 | <p>If the timer is started but nonrepeating, stop it.</p> |
955 | <p>If the timer is started but nonrepeating, stop it.</p> |
848 | <p>If the timer is repeating, either start it if necessary (with the repeat |
956 | <p>If the timer is repeating, either start it if necessary (with the repeat |
849 | value), or reset the running timer to the repeat value.</p> |
957 | value), or reset the running timer to the repeat value.</p> |
850 | <p>This sounds a bit complicated, but here is a useful and typical |
958 | <p>This sounds a bit complicated, but here is a useful and typical |
851 | example: Imagine you have a tcp connection and you want a so-called idle |
959 | example: Imagine you have a tcp connection and you want a so-called |
852 | timeout, that is, you want to be called when there have been, say, 60 |
960 | idle timeout, that is, you want to be called when there have been, |
853 | seconds of inactivity on the socket. The easiest way to do this is to |
961 | say, 60 seconds of inactivity on the socket. The easiest way to do |
854 | configure an <code>ev_timer</code> with after=repeat=60 and calling ev_timer_again each |
962 | this is to configure an <code>ev_timer</code> with <code>after</code>=<code>repeat</code>=<code>60</code> and calling |
855 | time you successfully read or write some data. If you go into an idle |
963 | <code>ev_timer_again</code> each time you successfully read or write some data. If |
856 | state where you do not expect data to travel on the socket, you can stop |
964 | you go into an idle state where you do not expect data to travel on the |
857 | the timer, and again will automatically restart it if need be.</p> |
965 | socket, you can stop the timer, and again will automatically restart it if |
|
|
966 | need be.</p> |
|
|
967 | <p>You can also ignore the <code>after</code> value and <code>ev_timer_start</code> altogether |
|
|
968 | and only ever use the <code>repeat</code> value:</p> |
|
|
969 | <pre> ev_timer_init (timer, callback, 0., 5.); |
|
|
970 | ev_timer_again (loop, timer); |
|
|
971 | ... |
|
|
972 | timer->again = 17.; |
|
|
973 | ev_timer_again (loop, timer); |
|
|
974 | ... |
|
|
975 | timer->again = 10.; |
|
|
976 | ev_timer_again (loop, timer); |
|
|
977 | |
|
|
978 | </pre> |
|
|
979 | <p>This is more efficient then stopping/starting the timer eahc time you want |
|
|
980 | to modify its timeout value.</p> |
|
|
981 | </dd> |
|
|
982 | <dt>ev_tstamp repeat [read-write]</dt> |
|
|
983 | <dd> |
|
|
984 | <p>The current <code>repeat</code> value. Will be used each time the watcher times out |
|
|
985 | or <code>ev_timer_again</code> is called and determines the next timeout (if any), |
|
|
986 | which is also when any modifications are taken into account.</p> |
858 | </dd> |
987 | </dd> |
859 | </dl> |
988 | </dl> |
860 | <p>Example: create a timer that fires after 60 seconds.</p> |
989 | <p>Example: Create a timer that fires after 60 seconds.</p> |
861 | <pre> static void |
990 | <pre> static void |
862 | one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
991 | one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
863 | { |
992 | { |
864 | .. one minute over, w is actually stopped right here |
993 | .. one minute over, w is actually stopped right here |
865 | } |
994 | } |
… | |
… | |
867 | struct ev_timer mytimer; |
996 | struct ev_timer mytimer; |
868 | ev_timer_init (&mytimer, one_minute_cb, 60., 0.); |
997 | ev_timer_init (&mytimer, one_minute_cb, 60., 0.); |
869 | ev_timer_start (loop, &mytimer); |
998 | ev_timer_start (loop, &mytimer); |
870 | |
999 | |
871 | </pre> |
1000 | </pre> |
872 | <p>Example: create a timeout timer that times out after 10 seconds of |
1001 | <p>Example: Create a timeout timer that times out after 10 seconds of |
873 | inactivity.</p> |
1002 | inactivity.</p> |
874 | <pre> static void |
1003 | <pre> static void |
875 | timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1004 | timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
876 | { |
1005 | { |
877 | .. ten seconds without any activity |
1006 | .. ten seconds without any activity |
… | |
… | |
980 | <p>Simply stops and restarts the periodic watcher again. This is only useful |
1109 | <p>Simply stops and restarts the periodic watcher again. This is only useful |
981 | when you changed some parameters or the reschedule callback would return |
1110 | when you changed some parameters or the reschedule callback would return |
982 | a different time than the last time it was called (e.g. in a crond like |
1111 | a different time than the last time it was called (e.g. in a crond like |
983 | program when the crontabs have changed).</p> |
1112 | program when the crontabs have changed).</p> |
984 | </dd> |
1113 | </dd> |
|
|
1114 | <dt>ev_tstamp interval [read-write]</dt> |
|
|
1115 | <dd> |
|
|
1116 | <p>The current interval value. Can be modified any time, but changes only |
|
|
1117 | take effect when the periodic timer fires or <code>ev_periodic_again</code> is being |
|
|
1118 | called.</p> |
|
|
1119 | </dd> |
|
|
1120 | <dt>ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write]</dt> |
|
|
1121 | <dd> |
|
|
1122 | <p>The current reschedule callback, or <code>0</code>, if this functionality is |
|
|
1123 | switched off. Can be changed any time, but changes only take effect when |
|
|
1124 | the periodic timer fires or <code>ev_periodic_again</code> is being called.</p> |
|
|
1125 | </dd> |
985 | </dl> |
1126 | </dl> |
986 | <p>Example: call a callback every hour, or, more precisely, whenever the |
1127 | <p>Example: Call a callback every hour, or, more precisely, whenever the |
987 | system clock is divisible by 3600. The callback invocation times have |
1128 | system clock is divisible by 3600. The callback invocation times have |
988 | potentially a lot of jittering, but good long-term stability.</p> |
1129 | potentially a lot of jittering, but good long-term stability.</p> |
989 | <pre> static void |
1130 | <pre> static void |
990 | clock_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
1131 | clock_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
991 | { |
1132 | { |
… | |
… | |
995 | struct ev_periodic hourly_tick; |
1136 | struct ev_periodic hourly_tick; |
996 | ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); |
1137 | ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); |
997 | ev_periodic_start (loop, &hourly_tick); |
1138 | ev_periodic_start (loop, &hourly_tick); |
998 | |
1139 | |
999 | </pre> |
1140 | </pre> |
1000 | <p>Example: the same as above, but use a reschedule callback to do it:</p> |
1141 | <p>Example: The same as above, but use a reschedule callback to do it:</p> |
1001 | <pre> #include <math.h> |
1142 | <pre> #include <math.h> |
1002 | |
1143 | |
1003 | static ev_tstamp |
1144 | static ev_tstamp |
1004 | my_scheduler_cb (struct ev_periodic *w, ev_tstamp now) |
1145 | my_scheduler_cb (struct ev_periodic *w, ev_tstamp now) |
1005 | { |
1146 | { |
… | |
… | |
1007 | } |
1148 | } |
1008 | |
1149 | |
1009 | ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); |
1150 | ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); |
1010 | |
1151 | |
1011 | </pre> |
1152 | </pre> |
1012 | <p>Example: call a callback every hour, starting now:</p> |
1153 | <p>Example: Call a callback every hour, starting now:</p> |
1013 | <pre> struct ev_periodic hourly_tick; |
1154 | <pre> struct ev_periodic hourly_tick; |
1014 | ev_periodic_init (&hourly_tick, clock_cb, |
1155 | ev_periodic_init (&hourly_tick, clock_cb, |
1015 | fmod (ev_now (loop), 3600.), 3600., 0); |
1156 | fmod (ev_now (loop), 3600.), 3600., 0); |
1016 | ev_periodic_start (loop, &hourly_tick); |
1157 | ev_periodic_start (loop, &hourly_tick); |
1017 | |
1158 | |
… | |
… | |
1038 | <dt>ev_signal_set (ev_signal *, int signum)</dt> |
1179 | <dt>ev_signal_set (ev_signal *, int signum)</dt> |
1039 | <dd> |
1180 | <dd> |
1040 | <p>Configures the watcher to trigger on the given signal number (usually one |
1181 | <p>Configures the watcher to trigger on the given signal number (usually one |
1041 | of the <code>SIGxxx</code> constants).</p> |
1182 | of the <code>SIGxxx</code> constants).</p> |
1042 | </dd> |
1183 | </dd> |
|
|
1184 | <dt>int signum [read-only]</dt> |
|
|
1185 | <dd> |
|
|
1186 | <p>The signal the watcher watches out for.</p> |
|
|
1187 | </dd> |
1043 | </dl> |
1188 | </dl> |
1044 | |
1189 | |
1045 | |
1190 | |
1046 | |
1191 | |
1047 | |
1192 | |
… | |
… | |
1060 | at the <code>rstatus</code> member of the <code>ev_child</code> watcher structure to see |
1205 | at the <code>rstatus</code> member of the <code>ev_child</code> watcher structure to see |
1061 | the status word (use the macros from <code>sys/wait.h</code> and see your systems |
1206 | the status word (use the macros from <code>sys/wait.h</code> and see your systems |
1062 | <code>waitpid</code> documentation). The <code>rpid</code> member contains the pid of the |
1207 | <code>waitpid</code> documentation). The <code>rpid</code> member contains the pid of the |
1063 | process causing the status change.</p> |
1208 | process causing the status change.</p> |
1064 | </dd> |
1209 | </dd> |
|
|
1210 | <dt>int pid [read-only]</dt> |
|
|
1211 | <dd> |
|
|
1212 | <p>The process id this watcher watches out for, or <code>0</code>, meaning any process id.</p> |
|
|
1213 | </dd> |
|
|
1214 | <dt>int rpid [read-write]</dt> |
|
|
1215 | <dd> |
|
|
1216 | <p>The process id that detected a status change.</p> |
|
|
1217 | </dd> |
|
|
1218 | <dt>int rstatus [read-write]</dt> |
|
|
1219 | <dd> |
|
|
1220 | <p>The process exit/trace status caused by <code>rpid</code> (see your systems |
|
|
1221 | <code>waitpid</code> and <code>sys/wait.h</code> documentation for details).</p> |
|
|
1222 | </dd> |
1065 | </dl> |
1223 | </dl> |
1066 | <p>Example: try to exit cleanly on SIGINT and SIGTERM.</p> |
1224 | <p>Example: Try to exit cleanly on SIGINT and SIGTERM.</p> |
1067 | <pre> static void |
1225 | <pre> static void |
1068 | sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
1226 | sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
1069 | { |
1227 | { |
1070 | ev_unloop (loop, EVUNLOOP_ALL); |
1228 | ev_unloop (loop, EVUNLOOP_ALL); |
1071 | } |
1229 | } |
1072 | |
1230 | |
1073 | struct ev_signal signal_watcher; |
1231 | struct ev_signal signal_watcher; |
1074 | ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
1232 | ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
1075 | ev_signal_start (loop, &sigint_cb); |
1233 | ev_signal_start (loop, &sigint_cb); |
|
|
1234 | |
|
|
1235 | |
|
|
1236 | |
|
|
1237 | |
|
|
1238 | </pre> |
|
|
1239 | |
|
|
1240 | </div> |
|
|
1241 | <h2 id="code_ev_stat_code_did_the_file_attri"><code>ev_stat</code> - did the file attributes just change?</h2> |
|
|
1242 | <div id="code_ev_stat_code_did_the_file_attri-2"> |
|
|
1243 | <p>This watches a filesystem path for attribute changes. That is, it calls |
|
|
1244 | <code>stat</code> regularly (or when the OS says it changed) and sees if it changed |
|
|
1245 | compared to the last time, invoking the callback if it did.</p> |
|
|
1246 | <p>The path does not need to exist: changing from "path exists" to "path does |
|
|
1247 | not exist" is a status change like any other. The condition "path does |
|
|
1248 | not exist" is signified by the <code>st_nlink</code> field being zero (which is |
|
|
1249 | otherwise always forced to be at least one) and all the other fields of |
|
|
1250 | the stat buffer having unspecified contents.</p> |
|
|
1251 | <p>Since there is no standard to do this, the portable implementation simply |
|
|
1252 | calls <code>stat (2)</code> regularly on the path to see if it changed somehow. You |
|
|
1253 | can specify a recommended polling interval for this case. If you specify |
|
|
1254 | a polling interval of <code>0</code> (highly recommended!) then a <i>suitable, |
|
|
1255 | unspecified default</i> value will be used (which you can expect to be around |
|
|
1256 | five seconds, although this might change dynamically). Libev will also |
|
|
1257 | impose a minimum interval which is currently around <code>0.1</code>, but thats |
|
|
1258 | usually overkill.</p> |
|
|
1259 | <p>This watcher type is not meant for massive numbers of stat watchers, |
|
|
1260 | as even with OS-supported change notifications, this can be |
|
|
1261 | resource-intensive.</p> |
|
|
1262 | <p>At the time of this writing, only the Linux inotify interface is |
|
|
1263 | implemented (implementing kqueue support is left as an exercise for the |
|
|
1264 | reader). Inotify will be used to give hints only and should not change the |
|
|
1265 | semantics of <code>ev_stat</code> watchers, which means that libev sometimes needs |
|
|
1266 | to fall back to regular polling again even with inotify, but changes are |
|
|
1267 | usually detected immediately, and if the file exists there will be no |
|
|
1268 | polling.</p> |
|
|
1269 | <dl> |
|
|
1270 | <dt>ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)</dt> |
|
|
1271 | <dt>ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)</dt> |
|
|
1272 | <dd> |
|
|
1273 | <p>Configures the watcher to wait for status changes of the given |
|
|
1274 | <code>path</code>. The <code>interval</code> is a hint on how quickly a change is expected to |
|
|
1275 | be detected and should normally be specified as <code>0</code> to let libev choose |
|
|
1276 | a suitable value. The memory pointed to by <code>path</code> must point to the same |
|
|
1277 | path for as long as the watcher is active.</p> |
|
|
1278 | <p>The callback will be receive <code>EV_STAT</code> when a change was detected, |
|
|
1279 | relative to the attributes at the time the watcher was started (or the |
|
|
1280 | last change was detected).</p> |
|
|
1281 | </dd> |
|
|
1282 | <dt>ev_stat_stat (ev_stat *)</dt> |
|
|
1283 | <dd> |
|
|
1284 | <p>Updates the stat buffer immediately with new values. If you change the |
|
|
1285 | watched path in your callback, you could call this fucntion to avoid |
|
|
1286 | detecting this change (while introducing a race condition). Can also be |
|
|
1287 | useful simply to find out the new values.</p> |
|
|
1288 | </dd> |
|
|
1289 | <dt>ev_statdata attr [read-only]</dt> |
|
|
1290 | <dd> |
|
|
1291 | <p>The most-recently detected attributes of the file. Although the type is of |
|
|
1292 | <code>ev_statdata</code>, this is usually the (or one of the) <code>struct stat</code> types |
|
|
1293 | suitable for your system. If the <code>st_nlink</code> member is <code>0</code>, then there |
|
|
1294 | was some error while <code>stat</code>ing the file.</p> |
|
|
1295 | </dd> |
|
|
1296 | <dt>ev_statdata prev [read-only]</dt> |
|
|
1297 | <dd> |
|
|
1298 | <p>The previous attributes of the file. The callback gets invoked whenever |
|
|
1299 | <code>prev</code> != <code>attr</code>.</p> |
|
|
1300 | </dd> |
|
|
1301 | <dt>ev_tstamp interval [read-only]</dt> |
|
|
1302 | <dd> |
|
|
1303 | <p>The specified interval.</p> |
|
|
1304 | </dd> |
|
|
1305 | <dt>const char *path [read-only]</dt> |
|
|
1306 | <dd> |
|
|
1307 | <p>The filesystem path that is being watched.</p> |
|
|
1308 | </dd> |
|
|
1309 | </dl> |
|
|
1310 | <p>Example: Watch <code>/etc/passwd</code> for attribute changes.</p> |
|
|
1311 | <pre> static void |
|
|
1312 | passwd_cb (struct ev_loop *loop, ev_stat *w, int revents) |
|
|
1313 | { |
|
|
1314 | /* /etc/passwd changed in some way */ |
|
|
1315 | if (w->attr.st_nlink) |
|
|
1316 | { |
|
|
1317 | printf ("passwd current size %ld\n", (long)w->attr.st_size); |
|
|
1318 | printf ("passwd current atime %ld\n", (long)w->attr.st_mtime); |
|
|
1319 | printf ("passwd current mtime %ld\n", (long)w->attr.st_mtime); |
|
|
1320 | } |
|
|
1321 | else |
|
|
1322 | /* you shalt not abuse printf for puts */ |
|
|
1323 | puts ("wow, /etc/passwd is not there, expect problems. " |
|
|
1324 | "if this is windows, they already arrived\n"); |
|
|
1325 | } |
|
|
1326 | |
|
|
1327 | ... |
|
|
1328 | ev_stat passwd; |
|
|
1329 | |
|
|
1330 | ev_stat_init (&passwd, passwd_cb, "/etc/passwd"); |
|
|
1331 | ev_stat_start (loop, &passwd); |
1076 | |
1332 | |
1077 | |
1333 | |
1078 | |
1334 | |
1079 | |
1335 | |
1080 | </pre> |
1336 | </pre> |
… | |
… | |
1101 | <p>Initialises and configures the idle watcher - it has no parameters of any |
1357 | <p>Initialises and configures the idle watcher - it has no parameters of any |
1102 | kind. There is a <code>ev_idle_set</code> macro, but using it is utterly pointless, |
1358 | kind. There is a <code>ev_idle_set</code> macro, but using it is utterly pointless, |
1103 | believe me.</p> |
1359 | believe me.</p> |
1104 | </dd> |
1360 | </dd> |
1105 | </dl> |
1361 | </dl> |
1106 | <p>Example: dynamically allocate an <code>ev_idle</code>, start it, and in the |
1362 | <p>Example: Dynamically allocate an <code>ev_idle</code> watcher, start it, and in the |
1107 | callback, free it. Alos, use no error checking, as usual.</p> |
1363 | callback, free it. Also, use no error checking, as usual.</p> |
1108 | <pre> static void |
1364 | <pre> static void |
1109 | idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
1365 | idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
1110 | { |
1366 | { |
1111 | free (w); |
1367 | free (w); |
1112 | // now do something you wanted to do when the program has |
1368 | // now do something you wanted to do when the program has |
… | |
… | |
1126 | <h2 id="code_ev_prepare_code_and_code_ev_che"><code>ev_prepare</code> and <code>ev_check</code> - customise your event loop!</h2> |
1382 | <h2 id="code_ev_prepare_code_and_code_ev_che"><code>ev_prepare</code> and <code>ev_check</code> - customise your event loop!</h2> |
1127 | <div id="code_ev_prepare_code_and_code_ev_che-2"> |
1383 | <div id="code_ev_prepare_code_and_code_ev_che-2"> |
1128 | <p>Prepare and check watchers are usually (but not always) used in tandem: |
1384 | <p>Prepare and check watchers are usually (but not always) used in tandem: |
1129 | prepare watchers get invoked before the process blocks and check watchers |
1385 | prepare watchers get invoked before the process blocks and check watchers |
1130 | afterwards.</p> |
1386 | afterwards.</p> |
|
|
1387 | <p>You <i>must not</i> call <code>ev_loop</code> or similar functions that enter |
|
|
1388 | the current event loop from either <code>ev_prepare</code> or <code>ev_check</code> |
|
|
1389 | watchers. Other loops than the current one are fine, however. The |
|
|
1390 | rationale behind this is that you do not need to check for recursion in |
|
|
1391 | those watchers, i.e. the sequence will always be <code>ev_prepare</code>, blocking, |
|
|
1392 | <code>ev_check</code> so if you have one watcher of each kind they will always be |
|
|
1393 | called in pairs bracketing the blocking call.</p> |
1131 | <p>Their main purpose is to integrate other event mechanisms into libev and |
1394 | <p>Their main purpose is to integrate other event mechanisms into libev and |
1132 | their use is somewhat advanced. This could be used, for example, to track |
1395 | their use is somewhat advanced. This could be used, for example, to track |
1133 | variable changes, implement your own watchers, integrate net-snmp or a |
1396 | variable changes, implement your own watchers, integrate net-snmp or a |
1134 | coroutine library and lots more.</p> |
1397 | coroutine library and lots more. They are also occasionally useful if |
|
|
1398 | you cache some data and want to flush it before blocking (for example, |
|
|
1399 | in X programs you might want to do an <code>XFlush ()</code> in an <code>ev_prepare</code> |
|
|
1400 | watcher).</p> |
1135 | <p>This is done by examining in each prepare call which file descriptors need |
1401 | <p>This is done by examining in each prepare call which file descriptors need |
1136 | to be watched by the other library, registering <code>ev_io</code> watchers for |
1402 | to be watched by the other library, registering <code>ev_io</code> watchers for |
1137 | them and starting an <code>ev_timer</code> watcher for any timeouts (many libraries |
1403 | them and starting an <code>ev_timer</code> watcher for any timeouts (many libraries |
1138 | provide just this functionality). Then, in the check watcher you check for |
1404 | provide just this functionality). Then, in the check watcher you check for |
1139 | any events that occured (by checking the pending status of all watchers |
1405 | any events that occured (by checking the pending status of all watchers |
… | |
… | |
1155 | <p>Initialises and configures the prepare or check watcher - they have no |
1421 | <p>Initialises and configures the prepare or check watcher - they have no |
1156 | parameters of any kind. There are <code>ev_prepare_set</code> and <code>ev_check_set</code> |
1422 | parameters of any kind. There are <code>ev_prepare_set</code> and <code>ev_check_set</code> |
1157 | macros, but using them is utterly, utterly and completely pointless.</p> |
1423 | macros, but using them is utterly, utterly and completely pointless.</p> |
1158 | </dd> |
1424 | </dd> |
1159 | </dl> |
1425 | </dl> |
1160 | <p>Example: *TODO*.</p> |
1426 | <p>Example: To include a library such as adns, you would add IO watchers |
|
|
1427 | and a timeout watcher in a prepare handler, as required by libadns, and |
|
|
1428 | in a check watcher, destroy them and call into libadns. What follows is |
|
|
1429 | pseudo-code only of course:</p> |
|
|
1430 | <pre> static ev_io iow [nfd]; |
|
|
1431 | static ev_timer tw; |
1161 | |
1432 | |
|
|
1433 | static void |
|
|
1434 | io_cb (ev_loop *loop, ev_io *w, int revents) |
|
|
1435 | { |
|
|
1436 | // set the relevant poll flags |
|
|
1437 | // could also call adns_processreadable etc. here |
|
|
1438 | struct pollfd *fd = (struct pollfd *)w->data; |
|
|
1439 | if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
|
|
1440 | if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
|
|
1441 | } |
1162 | |
1442 | |
|
|
1443 | // create io watchers for each fd and a timer before blocking |
|
|
1444 | static void |
|
|
1445 | adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
|
|
1446 | { |
|
|
1447 | int timeout = 3600000;truct pollfd fds [nfd]; |
|
|
1448 | // actual code will need to loop here and realloc etc. |
|
|
1449 | adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
1163 | |
1450 | |
|
|
1451 | /* the callback is illegal, but won't be called as we stop during check */ |
|
|
1452 | ev_timer_init (&tw, 0, timeout * 1e-3); |
|
|
1453 | ev_timer_start (loop, &tw); |
1164 | |
1454 | |
|
|
1455 | // create on ev_io per pollfd |
|
|
1456 | for (int i = 0; i < nfd; ++i) |
|
|
1457 | { |
|
|
1458 | ev_io_init (iow + i, io_cb, fds [i].fd, |
|
|
1459 | ((fds [i].events & POLLIN ? EV_READ : 0) |
|
|
1460 | | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
|
|
1461 | |
|
|
1462 | fds [i].revents = 0; |
|
|
1463 | iow [i].data = fds + i; |
|
|
1464 | ev_io_start (loop, iow + i); |
|
|
1465 | } |
|
|
1466 | } |
|
|
1467 | |
|
|
1468 | // stop all watchers after blocking |
|
|
1469 | static void |
|
|
1470 | adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
|
|
1471 | { |
|
|
1472 | ev_timer_stop (loop, &tw); |
|
|
1473 | |
|
|
1474 | for (int i = 0; i < nfd; ++i) |
|
|
1475 | ev_io_stop (loop, iow + i); |
|
|
1476 | |
|
|
1477 | adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
|
|
1478 | } |
|
|
1479 | |
|
|
1480 | |
|
|
1481 | |
|
|
1482 | |
|
|
1483 | </pre> |
1165 | |
1484 | |
1166 | </div> |
1485 | </div> |
1167 | <h2 id="code_ev_embed_code_when_one_backend_"><code>ev_embed</code> - when one backend isn't enough...</h2> |
1486 | <h2 id="code_ev_embed_code_when_one_backend_"><code>ev_embed</code> - when one backend isn't enough...</h2> |
1168 | <div id="code_ev_embed_code_when_one_backend_-2"> |
1487 | <div id="code_ev_embed_code_when_one_backend_-2"> |
1169 | <p>This is a rather advanced watcher type that lets you embed one event loop |
1488 | <p>This is a rather advanced watcher type that lets you embed one event loop |
… | |
… | |
1240 | <dd> |
1559 | <dd> |
1241 | <p>Make a single, non-blocking sweep over the embedded loop. This works |
1560 | <p>Make a single, non-blocking sweep over the embedded loop. This works |
1242 | similarly to <code>ev_loop (embedded_loop, EVLOOP_NONBLOCK)</code>, but in the most |
1561 | similarly to <code>ev_loop (embedded_loop, EVLOOP_NONBLOCK)</code>, but in the most |
1243 | apropriate way for embedded loops.</p> |
1562 | apropriate way for embedded loops.</p> |
1244 | </dd> |
1563 | </dd> |
|
|
1564 | <dt>struct ev_loop *loop [read-only]</dt> |
|
|
1565 | <dd> |
|
|
1566 | <p>The embedded event loop.</p> |
|
|
1567 | </dd> |
1245 | </dl> |
1568 | </dl> |
1246 | |
1569 | |
1247 | |
1570 | |
1248 | |
1571 | |
1249 | |
1572 | |
1250 | |
1573 | |
1251 | </div> |
1574 | </div> |
1252 | <h1 id="OTHER_FUNCTIONS">OTHER FUNCTIONS</h1><p><a href="#TOP" class="toplink">Top</a></p> |
1575 | <h2 id="code_ev_fork_code_the_audacity_to_re"><code>ev_fork</code> - the audacity to resume the event loop after a fork</h2> |
|
|
1576 | <div id="code_ev_fork_code_the_audacity_to_re-2"> |
|
|
1577 | <p>Fork watchers are called when a <code>fork ()</code> was detected (usually because |
|
|
1578 | whoever is a good citizen cared to tell libev about it by calling |
|
|
1579 | <code>ev_default_fork</code> or <code>ev_loop_fork</code>). The invocation is done before the |
|
|
1580 | event loop blocks next and before <code>ev_check</code> watchers are being called, |
|
|
1581 | and only in the child after the fork. If whoever good citizen calling |
|
|
1582 | <code>ev_default_fork</code> cheats and calls it in the wrong process, the fork |
|
|
1583 | handlers will be invoked, too, of course.</p> |
|
|
1584 | <dl> |
|
|
1585 | <dt>ev_fork_init (ev_signal *, callback)</dt> |
|
|
1586 | <dd> |
|
|
1587 | <p>Initialises and configures the fork watcher - it has no parameters of any |
|
|
1588 | kind. There is a <code>ev_fork_set</code> macro, but using it is utterly pointless, |
|
|
1589 | believe me.</p> |
|
|
1590 | </dd> |
|
|
1591 | </dl> |
|
|
1592 | |
|
|
1593 | |
|
|
1594 | |
|
|
1595 | |
|
|
1596 | |
|
|
1597 | </div> |
|
|
1598 | <h1 id="OTHER_FUNCTIONS">OTHER FUNCTIONS</h1> |
1253 | <div id="OTHER_FUNCTIONS_CONTENT"> |
1599 | <div id="OTHER_FUNCTIONS_CONTENT"> |
1254 | <p>There are some other functions of possible interest. Described. Here. Now.</p> |
1600 | <p>There are some other functions of possible interest. Described. Here. Now.</p> |
1255 | <dl> |
1601 | <dl> |
1256 | <dt>ev_once (loop, int fd, int events, ev_tstamp timeout, callback)</dt> |
1602 | <dt>ev_once (loop, int fd, int events, ev_tstamp timeout, callback)</dt> |
1257 | <dd> |
1603 | <dd> |
… | |
… | |
1304 | |
1650 | |
1305 | |
1651 | |
1306 | |
1652 | |
1307 | |
1653 | |
1308 | </div> |
1654 | </div> |
1309 | <h1 id="LIBEVENT_EMULATION">LIBEVENT EMULATION</h1><p><a href="#TOP" class="toplink">Top</a></p> |
1655 | <h1 id="LIBEVENT_EMULATION">LIBEVENT EMULATION</h1> |
1310 | <div id="LIBEVENT_EMULATION_CONTENT"> |
1656 | <div id="LIBEVENT_EMULATION_CONTENT"> |
1311 | <p>Libev offers a compatibility emulation layer for libevent. It cannot |
1657 | <p>Libev offers a compatibility emulation layer for libevent. It cannot |
1312 | emulate the internals of libevent, so here are some usage hints:</p> |
1658 | emulate the internals of libevent, so here are some usage hints:</p> |
1313 | <dl> |
1659 | <dl> |
1314 | <dt>* Use it by including <event.h>, as usual.</dt> |
1660 | <dt>* Use it by including <event.h>, as usual.</dt> |
… | |
… | |
1324 | <dt>* The libev emulation is <i>not</i> ABI compatible to libevent, you need |
1670 | <dt>* The libev emulation is <i>not</i> ABI compatible to libevent, you need |
1325 | to use the libev header file and library.</dt> |
1671 | to use the libev header file and library.</dt> |
1326 | </dl> |
1672 | </dl> |
1327 | |
1673 | |
1328 | </div> |
1674 | </div> |
1329 | <h1 id="C_SUPPORT">C++ SUPPORT</h1><p><a href="#TOP" class="toplink">Top</a></p> |
1675 | <h1 id="C_SUPPORT">C++ SUPPORT</h1> |
1330 | <div id="C_SUPPORT_CONTENT"> |
1676 | <div id="C_SUPPORT_CONTENT"> |
1331 | <p>Libev comes with some simplistic wrapper classes for C++ that mainly allow |
1677 | <p>Libev comes with some simplistic wrapper classes for C++ that mainly allow |
1332 | you to use some convinience methods to start/stop watchers and also change |
1678 | you to use some convinience methods to start/stop watchers and also change |
1333 | the callback model to a model using method callbacks on objects.</p> |
1679 | the callback model to a model using method callbacks on objects.</p> |
1334 | <p>To use it,</p> |
1680 | <p>To use it,</p> |
… | |
… | |
1398 | </dd> |
1744 | </dd> |
1399 | <dt>w->sweep () <code>ev::embed</code> only</dt> |
1745 | <dt>w->sweep () <code>ev::embed</code> only</dt> |
1400 | <dd> |
1746 | <dd> |
1401 | <p>Invokes <code>ev_embed_sweep</code>.</p> |
1747 | <p>Invokes <code>ev_embed_sweep</code>.</p> |
1402 | </dd> |
1748 | </dd> |
|
|
1749 | <dt>w->update () <code>ev::stat</code> only</dt> |
|
|
1750 | <dd> |
|
|
1751 | <p>Invokes <code>ev_stat_stat</code>.</p> |
|
|
1752 | </dd> |
1403 | </dl> |
1753 | </dl> |
1404 | </p> |
1754 | </p> |
1405 | </dd> |
1755 | </dd> |
1406 | </dl> |
1756 | </dl> |
1407 | <p>Example: Define a class with an IO and idle watcher, start one of them in |
1757 | <p>Example: Define a class with an IO and idle watcher, start one of them in |
… | |
… | |
1419 | idle (this, &myclass::idle_cb) |
1769 | idle (this, &myclass::idle_cb) |
1420 | { |
1770 | { |
1421 | io.start (fd, ev::READ); |
1771 | io.start (fd, ev::READ); |
1422 | } |
1772 | } |
1423 | |
1773 | |
1424 | </pre> |
|
|
1425 | |
1774 | |
|
|
1775 | |
|
|
1776 | |
|
|
1777 | </pre> |
|
|
1778 | |
1426 | </div> |
1779 | </div> |
1427 | <h1 id="EMBEDDING">EMBEDDING</h1><p><a href="#TOP" class="toplink">Top</a></p> |
1780 | <h1 id="MACRO_MAGIC">MACRO MAGIC</h1> |
|
|
1781 | <div id="MACRO_MAGIC_CONTENT"> |
|
|
1782 | <p>Libev can be compiled with a variety of options, the most fundemantal is |
|
|
1783 | <code>EV_MULTIPLICITY</code>. This option determines wether (most) functions and |
|
|
1784 | callbacks have an initial <code>struct ev_loop *</code> argument.</p> |
|
|
1785 | <p>To make it easier to write programs that cope with either variant, the |
|
|
1786 | following macros are defined:</p> |
|
|
1787 | <dl> |
|
|
1788 | <dt><code>EV_A</code>, <code>EV_A_</code></dt> |
|
|
1789 | <dd> |
|
|
1790 | <p>This provides the loop <i>argument</i> for functions, if one is required ("ev |
|
|
1791 | loop argument"). The <code>EV_A</code> form is used when this is the sole argument, |
|
|
1792 | <code>EV_A_</code> is used when other arguments are following. Example:</p> |
|
|
1793 | <pre> ev_unref (EV_A); |
|
|
1794 | ev_timer_add (EV_A_ watcher); |
|
|
1795 | ev_loop (EV_A_ 0); |
|
|
1796 | |
|
|
1797 | </pre> |
|
|
1798 | <p>It assumes the variable <code>loop</code> of type <code>struct ev_loop *</code> is in scope, |
|
|
1799 | which is often provided by the following macro.</p> |
|
|
1800 | </dd> |
|
|
1801 | <dt><code>EV_P</code>, <code>EV_P_</code></dt> |
|
|
1802 | <dd> |
|
|
1803 | <p>This provides the loop <i>parameter</i> for functions, if one is required ("ev |
|
|
1804 | loop parameter"). The <code>EV_P</code> form is used when this is the sole parameter, |
|
|
1805 | <code>EV_P_</code> is used when other parameters are following. Example:</p> |
|
|
1806 | <pre> // this is how ev_unref is being declared |
|
|
1807 | static void ev_unref (EV_P); |
|
|
1808 | |
|
|
1809 | // this is how you can declare your typical callback |
|
|
1810 | static void cb (EV_P_ ev_timer *w, int revents) |
|
|
1811 | |
|
|
1812 | </pre> |
|
|
1813 | <p>It declares a parameter <code>loop</code> of type <code>struct ev_loop *</code>, quite |
|
|
1814 | suitable for use with <code>EV_A</code>.</p> |
|
|
1815 | </dd> |
|
|
1816 | <dt><code>EV_DEFAULT</code>, <code>EV_DEFAULT_</code></dt> |
|
|
1817 | <dd> |
|
|
1818 | <p>Similar to the other two macros, this gives you the value of the default |
|
|
1819 | loop, if multiple loops are supported ("ev loop default").</p> |
|
|
1820 | </dd> |
|
|
1821 | </dl> |
|
|
1822 | <p>Example: Declare and initialise a check watcher, working regardless of |
|
|
1823 | wether multiple loops are supported or not.</p> |
|
|
1824 | <pre> static void |
|
|
1825 | check_cb (EV_P_ ev_timer *w, int revents) |
|
|
1826 | { |
|
|
1827 | ev_check_stop (EV_A_ w); |
|
|
1828 | } |
|
|
1829 | |
|
|
1830 | ev_check check; |
|
|
1831 | ev_check_init (&check, check_cb); |
|
|
1832 | ev_check_start (EV_DEFAULT_ &check); |
|
|
1833 | ev_loop (EV_DEFAULT_ 0); |
|
|
1834 | |
|
|
1835 | |
|
|
1836 | |
|
|
1837 | |
|
|
1838 | </pre> |
|
|
1839 | |
|
|
1840 | </div> |
|
|
1841 | <h1 id="EMBEDDING">EMBEDDING</h1> |
1428 | <div id="EMBEDDING_CONTENT"> |
1842 | <div id="EMBEDDING_CONTENT"> |
1429 | <p>Libev can (and often is) directly embedded into host |
1843 | <p>Libev can (and often is) directly embedded into host |
1430 | applications. Examples of applications that embed it include the Deliantra |
1844 | applications. Examples of applications that embed it include the Deliantra |
1431 | Game Server, the EV perl module, the GNU Virtual Private Ethernet (gvpe) |
1845 | Game Server, the EV perl module, the GNU Virtual Private Ethernet (gvpe) |
1432 | and rxvt-unicode.</p> |
1846 | and rxvt-unicode.</p> |
… | |
… | |
1469 | ev_vars.h |
1883 | ev_vars.h |
1470 | ev_wrap.h |
1884 | ev_wrap.h |
1471 | |
1885 | |
1472 | ev_win32.c required on win32 platforms only |
1886 | ev_win32.c required on win32 platforms only |
1473 | |
1887 | |
1474 | ev_select.c only when select backend is enabled (which is is by default) |
1888 | ev_select.c only when select backend is enabled (which is by default) |
1475 | ev_poll.c only when poll backend is enabled (disabled by default) |
1889 | ev_poll.c only when poll backend is enabled (disabled by default) |
1476 | ev_epoll.c only when the epoll backend is enabled (disabled by default) |
1890 | ev_epoll.c only when the epoll backend is enabled (disabled by default) |
1477 | ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
1891 | ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
1478 | ev_port.c only when the solaris port backend is enabled (disabled by default) |
1892 | ev_port.c only when the solaris port backend is enabled (disabled by default) |
1479 | |
1893 | |
1480 | </pre> |
1894 | </pre> |
1481 | <p><cite>ev.c</cite> includes the backend files directly when enabled, so you only need |
1895 | <p><cite>ev.c</cite> includes the backend files directly when enabled, so you only need |
1482 | to compile a single file.</p> |
1896 | to compile this single file.</p> |
1483 | |
1897 | |
1484 | </div> |
1898 | </div> |
1485 | <h3 id="LIBEVENT_COMPATIBILITY_API">LIBEVENT COMPATIBILITY API</h3> |
1899 | <h3 id="LIBEVENT_COMPATIBILITY_API">LIBEVENT COMPATIBILITY API</h3> |
1486 | <div id="LIBEVENT_COMPATIBILITY_API_CONTENT"> |
1900 | <div id="LIBEVENT_COMPATIBILITY_API_CONTENT"> |
1487 | <p>To include the libevent compatibility API, also include:</p> |
1901 | <p>To include the libevent compatibility API, also include:</p> |
… | |
… | |
1502 | </div> |
1916 | </div> |
1503 | <h3 id="AUTOCONF_SUPPORT">AUTOCONF SUPPORT</h3> |
1917 | <h3 id="AUTOCONF_SUPPORT">AUTOCONF SUPPORT</h3> |
1504 | <div id="AUTOCONF_SUPPORT_CONTENT"> |
1918 | <div id="AUTOCONF_SUPPORT_CONTENT"> |
1505 | <p>Instead of using <code>EV_STANDALONE=1</code> and providing your config in |
1919 | <p>Instead of using <code>EV_STANDALONE=1</code> and providing your config in |
1506 | whatever way you want, you can also <code>m4_include([libev.m4])</code> in your |
1920 | whatever way you want, you can also <code>m4_include([libev.m4])</code> in your |
1507 | <cite>configure.ac</cite> and leave <code>EV_STANDALONE</code> off. <cite>ev.c</cite> will then include |
1921 | <cite>configure.ac</cite> and leave <code>EV_STANDALONE</code> undefined. <cite>ev.c</cite> will then |
1508 | <cite>config.h</cite> and configure itself accordingly.</p> |
1922 | include <cite>config.h</cite> and configure itself accordingly.</p> |
1509 | <p>For this of course you need the m4 file:</p> |
1923 | <p>For this of course you need the m4 file:</p> |
1510 | <pre> libev.m4 |
1924 | <pre> libev.m4 |
1511 | |
1925 | |
1512 | </pre> |
1926 | </pre> |
1513 | |
1927 | |
… | |
… | |
1606 | </dd> |
2020 | </dd> |
1607 | <dt>EV_USE_DEVPOLL</dt> |
2021 | <dt>EV_USE_DEVPOLL</dt> |
1608 | <dd> |
2022 | <dd> |
1609 | <p>reserved for future expansion, works like the USE symbols above.</p> |
2023 | <p>reserved for future expansion, works like the USE symbols above.</p> |
1610 | </dd> |
2024 | </dd> |
|
|
2025 | <dt>EV_USE_INOTIFY</dt> |
|
|
2026 | <dd> |
|
|
2027 | <p>If defined to be <code>1</code>, libev will compile in support for the Linux inotify |
|
|
2028 | interface to speed up <code>ev_stat</code> watchers. Its actual availability will |
|
|
2029 | be detected at runtime.</p> |
|
|
2030 | </dd> |
1611 | <dt>EV_H</dt> |
2031 | <dt>EV_H</dt> |
1612 | <dd> |
2032 | <dd> |
1613 | <p>The name of the <cite>ev.h</cite> header file used to include it. The default if |
2033 | <p>The name of the <cite>ev.h</cite> header file used to include it. The default if |
1614 | undefined is <code><ev.h></code> in <cite>event.h</cite> and <code>"ev.h"</code> in <cite>ev.c</cite>. This |
2034 | undefined is <code><ev.h></code> in <cite>event.h</cite> and <code>"ev.h"</code> in <cite>ev.c</cite>. This |
1615 | can be used to virtually rename the <cite>ev.h</cite> header file in case of conflicts.</p> |
2035 | can be used to virtually rename the <cite>ev.h</cite> header file in case of conflicts.</p> |
… | |
… | |
1638 | will have the <code>struct ev_loop *</code> as first argument, and you can create |
2058 | will have the <code>struct ev_loop *</code> as first argument, and you can create |
1639 | additional independent event loops. Otherwise there will be no support |
2059 | additional independent event loops. Otherwise there will be no support |
1640 | for multiple event loops and there is no first event loop pointer |
2060 | for multiple event loops and there is no first event loop pointer |
1641 | argument. Instead, all functions act on the single default loop.</p> |
2061 | argument. Instead, all functions act on the single default loop.</p> |
1642 | </dd> |
2062 | </dd> |
1643 | <dt>EV_PERIODICS</dt> |
2063 | <dt>EV_PERIODIC_ENABLE</dt> |
1644 | <dd> |
2064 | <dd> |
1645 | <p>If undefined or defined to be <code>1</code>, then periodic timers are supported, |
2065 | <p>If undefined or defined to be <code>1</code>, then periodic timers are supported. If |
1646 | otherwise not. This saves a few kb of code.</p> |
2066 | defined to be <code>0</code>, then they are not. Disabling them saves a few kB of |
|
|
2067 | code.</p> |
|
|
2068 | </dd> |
|
|
2069 | <dt>EV_EMBED_ENABLE</dt> |
|
|
2070 | <dd> |
|
|
2071 | <p>If undefined or defined to be <code>1</code>, then embed watchers are supported. If |
|
|
2072 | defined to be <code>0</code>, then they are not.</p> |
|
|
2073 | </dd> |
|
|
2074 | <dt>EV_STAT_ENABLE</dt> |
|
|
2075 | <dd> |
|
|
2076 | <p>If undefined or defined to be <code>1</code>, then stat watchers are supported. If |
|
|
2077 | defined to be <code>0</code>, then they are not.</p> |
|
|
2078 | </dd> |
|
|
2079 | <dt>EV_FORK_ENABLE</dt> |
|
|
2080 | <dd> |
|
|
2081 | <p>If undefined or defined to be <code>1</code>, then fork watchers are supported. If |
|
|
2082 | defined to be <code>0</code>, then they are not.</p> |
|
|
2083 | </dd> |
|
|
2084 | <dt>EV_MINIMAL</dt> |
|
|
2085 | <dd> |
|
|
2086 | <p>If you need to shave off some kilobytes of code at the expense of some |
|
|
2087 | speed, define this symbol to <code>1</code>. Currently only used for gcc to override |
|
|
2088 | some inlining decisions, saves roughly 30% codesize of amd64.</p> |
|
|
2089 | </dd> |
|
|
2090 | <dt>EV_PID_HASHSIZE</dt> |
|
|
2091 | <dd> |
|
|
2092 | <p><code>ev_child</code> watchers use a small hash table to distribute workload by |
|
|
2093 | pid. The default size is <code>16</code> (or <code>1</code> with <code>EV_MINIMAL</code>), usually more |
|
|
2094 | than enough. If you need to manage thousands of children you might want to |
|
|
2095 | increase this value (<i>must</i> be a power of two).</p> |
|
|
2096 | </dd> |
|
|
2097 | <dt>EV_INOTIFY_HASHSIZE</dt> |
|
|
2098 | <dd> |
|
|
2099 | <p><code>ev_staz</code> watchers use a small hash table to distribute workload by |
|
|
2100 | inotify watch id. The default size is <code>16</code> (or <code>1</code> with <code>EV_MINIMAL</code>), |
|
|
2101 | usually more than enough. If you need to manage thousands of <code>ev_stat</code> |
|
|
2102 | watchers you might want to increase this value (<i>must</i> be a power of |
|
|
2103 | two).</p> |
1647 | </dd> |
2104 | </dd> |
1648 | <dt>EV_COMMON</dt> |
2105 | <dt>EV_COMMON</dt> |
1649 | <dd> |
2106 | <dd> |
1650 | <p>By default, all watchers have a <code>void *data</code> member. By redefining |
2107 | <p>By default, all watchers have a <code>void *data</code> member. By redefining |
1651 | this macro to a something else you can include more and other types of |
2108 | this macro to a something else you can include more and other types of |
… | |
… | |
1656 | SV *self; /* contains this struct */ \ |
2113 | SV *self; /* contains this struct */ \ |
1657 | SV *cb_sv, *fh /* note no trailing ";" */ |
2114 | SV *cb_sv, *fh /* note no trailing ";" */ |
1658 | |
2115 | |
1659 | </pre> |
2116 | </pre> |
1660 | </dd> |
2117 | </dd> |
1661 | <dt>EV_CB_DECLARE(type)</dt> |
2118 | <dt>EV_CB_DECLARE (type)</dt> |
1662 | <dt>EV_CB_INVOKE(watcher,revents)</dt> |
2119 | <dt>EV_CB_INVOKE (watcher, revents)</dt> |
1663 | <dt>ev_set_cb(ev,cb)</dt> |
2120 | <dt>ev_set_cb (ev, cb)</dt> |
1664 | <dd> |
2121 | <dd> |
1665 | <p>Can be used to change the callback member declaration in each watcher, |
2122 | <p>Can be used to change the callback member declaration in each watcher, |
1666 | and the way callbacks are invoked and set. Must expand to a struct member |
2123 | and the way callbacks are invoked and set. Must expand to a struct member |
1667 | definition and a statement, respectively. See the <cite>ev.v</cite> header file for |
2124 | definition and a statement, respectively. See the <cite>ev.v</cite> header file for |
1668 | their default definitions. One possible use for overriding these is to |
2125 | their default definitions. One possible use for overriding these is to |
1669 | avoid the ev_loop pointer as first argument in all cases, or to use method |
2126 | avoid the <code>struct ev_loop *</code> as first argument in all cases, or to use |
1670 | calls instead of plain function calls in C++.</p> |
2127 | method calls instead of plain function calls in C++.</p> |
1671 | |
2128 | |
1672 | </div> |
2129 | </div> |
1673 | <h2 id="EXAMPLES">EXAMPLES</h2> |
2130 | <h2 id="EXAMPLES">EXAMPLES</h2> |
1674 | <div id="EXAMPLES_CONTENT"> |
2131 | <div id="EXAMPLES_CONTENT"> |
1675 | <p>For a real-world example of a program the includes libev |
2132 | <p>For a real-world example of a program the includes libev |
… | |
… | |
1691 | </pre> |
2148 | </pre> |
1692 | <p>And a <cite>ev_cpp.C</cite> implementation file that contains libev proper and is compiled:</p> |
2149 | <p>And a <cite>ev_cpp.C</cite> implementation file that contains libev proper and is compiled:</p> |
1693 | <pre> #include "ev_cpp.h" |
2150 | <pre> #include "ev_cpp.h" |
1694 | #include "ev.c" |
2151 | #include "ev.c" |
1695 | |
2152 | |
1696 | </pre> |
|
|
1697 | |
2153 | |
|
|
2154 | |
|
|
2155 | |
|
|
2156 | </pre> |
|
|
2157 | |
1698 | </div> |
2158 | </div> |
1699 | <h1 id="AUTHOR">AUTHOR</h1><p><a href="#TOP" class="toplink">Top</a></p> |
2159 | <h1 id="COMPLEXITIES">COMPLEXITIES</h1> |
|
|
2160 | <div id="COMPLEXITIES_CONTENT"> |
|
|
2161 | <p>In this section the complexities of (many of) the algorithms used inside |
|
|
2162 | libev will be explained. For complexity discussions about backends see the |
|
|
2163 | documentation for <code>ev_default_init</code>.</p> |
|
|
2164 | <p> |
|
|
2165 | <dl> |
|
|
2166 | <dt>Starting and stopping timer/periodic watchers: O(log skipped_other_timers)</dt> |
|
|
2167 | <dt>Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)</dt> |
|
|
2168 | <dt>Starting io/check/prepare/idle/signal/child watchers: O(1)</dt> |
|
|
2169 | <dt>Stopping check/prepare/idle watchers: O(1)</dt> |
|
|
2170 | <dt>Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))</dt> |
|
|
2171 | <dt>Finding the next timer per loop iteration: O(1)</dt> |
|
|
2172 | <dt>Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)</dt> |
|
|
2173 | <dt>Activating one watcher: O(1)</dt> |
|
|
2174 | </dl> |
|
|
2175 | </p> |
|
|
2176 | |
|
|
2177 | |
|
|
2178 | |
|
|
2179 | |
|
|
2180 | |
|
|
2181 | </div> |
|
|
2182 | <h1 id="AUTHOR">AUTHOR</h1> |
1700 | <div id="AUTHOR_CONTENT"> |
2183 | <div id="AUTHOR_CONTENT"> |
1701 | <p>Marc Lehmann <libev@schmorp.de>.</p> |
2184 | <p>Marc Lehmann <libev@schmorp.de>.</p> |
1702 | |
2185 | |
1703 | </div> |
2186 | </div> |
1704 | </div></body> |
2187 | </div></body> |