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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" /> |
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9 | <meta name="created" content="Tue Nov 27 09:11:42 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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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> |
36 | <li><a href="#code_ev_stat_code_did_the_file_attri"><code>ev_stat</code> - did the file attributes just change?</a></li> |
37 | <li><a href="#code_ev_stat_code_did_the_file_attri"><code>ev_stat</code> - did the file attributes just change?</a></li> |
37 | <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> |
38 | <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> |
39 | <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> |
40 | </ul> |
42 | </ul> |
41 | </li> |
43 | </li> |
42 | <li><a href="#OTHER_FUNCTIONS">OTHER FUNCTIONS</a></li> |
44 | <li><a href="#OTHER_FUNCTIONS">OTHER FUNCTIONS</a></li> |
43 | <li><a href="#LIBEVENT_EMULATION">LIBEVENT EMULATION</a></li> |
45 | <li><a href="#LIBEVENT_EMULATION">LIBEVENT EMULATION</a></li> |
44 | <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> |
45 | <li><a href="#EMBEDDING">EMBEDDING</a> |
48 | <li><a href="#EMBEDDING">EMBEDDING</a> |
46 | <ul><li><a href="#FILESETS">FILESETS</a> |
49 | <ul><li><a href="#FILESETS">FILESETS</a> |
47 | <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> |
48 | <li><a href="#LIBEVENT_COMPATIBILITY_API">LIBEVENT COMPATIBILITY API</a></li> |
51 | <li><a href="#LIBEVENT_COMPATIBILITY_API">LIBEVENT COMPATIBILITY API</a></li> |
49 | <li><a href="#AUTOCONF_SUPPORT">AUTOCONF SUPPORT</a></li> |
52 | <li><a href="#AUTOCONF_SUPPORT">AUTOCONF SUPPORT</a></li> |
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57 | <li><a href="#AUTHOR">AUTHOR</a> |
60 | <li><a href="#AUTHOR">AUTHOR</a> |
58 | </li> |
61 | </li> |
59 | </ul><hr /> |
62 | </ul><hr /> |
60 | <!-- INDEX END --> |
63 | <!-- INDEX END --> |
61 | |
64 | |
62 | <h1 id="NAME">NAME</h1><p><a href="#TOP" class="toplink">Top</a></p> |
65 | <h1 id="NAME">NAME</h1> |
63 | <div id="NAME_CONTENT"> |
66 | <div id="NAME_CONTENT"> |
64 | <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> |
65 | |
68 | |
66 | </div> |
69 | </div> |
67 | <h1 id="SYNOPSIS">SYNOPSIS</h1><p><a href="#TOP" class="toplink">Top</a></p> |
70 | <h1 id="SYNOPSIS">SYNOPSIS</h1> |
68 | <div id="SYNOPSIS_CONTENT"> |
71 | <div id="SYNOPSIS_CONTENT"> |
69 | <pre> #include <ev.h> |
72 | <pre> #include <ev.h> |
70 | |
73 | |
71 | </pre> |
74 | </pre> |
72 | |
75 | |
73 | </div> |
76 | </div> |
74 | <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> |
75 | <div id="DESCRIPTION_CONTENT"> |
123 | <div id="DESCRIPTION_CONTENT"> |
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124 | <p>The newest version of this document is also available as a html-formatted |
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125 | web page you might find easier to navigate when reading it for the first |
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126 | time: <a href="http://cvs.schmorp.de/libev/ev.html">http://cvs.schmorp.de/libev/ev.html</a>.</p> |
76 | <p>Libev is an event loop: you register interest in certain events (such as a |
127 | <p>Libev is an event loop: you register interest in certain events (such as a |
77 | file descriptor being readable or a timeout occuring), and it will manage |
128 | file descriptor being readable or a timeout occuring), and it will manage |
78 | these event sources and provide your program with events.</p> |
129 | these event sources and provide your program with events.</p> |
79 | <p>To do this, it must take more or less complete control over your process |
130 | <p>To do this, it must take more or less complete control over your process |
80 | (or thread) by executing the <i>event loop</i> handler, and will then |
131 | (or thread) by executing the <i>event loop</i> handler, and will then |
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83 | watchers</i>, which are relatively small C structures you initialise with the |
134 | watchers</i>, which are relatively small C structures you initialise with the |
84 | details of the event, and then hand it over to libev by <i>starting</i> the |
135 | details of the event, and then hand it over to libev by <i>starting</i> the |
85 | watcher.</p> |
136 | watcher.</p> |
86 | |
137 | |
87 | </div> |
138 | </div> |
88 | <h1 id="FEATURES">FEATURES</h1><p><a href="#TOP" class="toplink">Top</a></p> |
139 | <h1 id="FEATURES">FEATURES</h1> |
89 | <div id="FEATURES_CONTENT"> |
140 | <div id="FEATURES_CONTENT"> |
90 | <p>Libev supports select, poll, the linux-specific epoll and the bsd-specific |
141 | <p>Libev supports <code>select</code>, <code>poll</code>, the Linux-specific <code>epoll</code>, the |
91 | kqueue mechanisms for file descriptor events, relative timers, absolute |
142 | BSD-specific <code>kqueue</code> and the Solaris-specific event port mechanisms |
92 | timers with customised rescheduling, signal events, process status change |
143 | for file descriptor events (<code>ev_io</code>), the Linux <code>inotify</code> interface |
93 | events (related to SIGCHLD), and event watchers dealing with the event |
144 | (for <code>ev_stat</code>), relative timers (<code>ev_timer</code>), absolute timers |
94 | loop mechanism itself (idle, prepare and check watchers). It also is quite |
145 | with customised rescheduling (<code>ev_periodic</code>), synchronous signals |
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146 | (<code>ev_signal</code>), process status change events (<code>ev_child</code>), and event |
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147 | watchers dealing with the event loop mechanism itself (<code>ev_idle</code>, |
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148 | <code>ev_embed</code>, <code>ev_prepare</code> and <code>ev_check</code> watchers) as well as |
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149 | file watchers (<code>ev_stat</code>) and even limited support for fork events |
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150 | (<code>ev_fork</code>).</p> |
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151 | <p>It also is quite fast (see this |
95 | fast (see this <a href="http://libev.schmorp.de/bench.html">benchmark</a> comparing |
152 | <a href="http://libev.schmorp.de/bench.html">benchmark</a> comparing it to libevent |
96 | it to libevent for example).</p> |
153 | for example).</p> |
97 | |
154 | |
98 | </div> |
155 | </div> |
99 | <h1 id="CONVENTIONS">CONVENTIONS</h1><p><a href="#TOP" class="toplink">Top</a></p> |
156 | <h1 id="CONVENTIONS">CONVENTIONS</h1> |
100 | <div id="CONVENTIONS_CONTENT"> |
157 | <div id="CONVENTIONS_CONTENT"> |
101 | <p>Libev is very configurable. In this manual the default configuration |
158 | <p>Libev is very configurable. In this manual the default configuration will |
102 | will be described, which supports multiple event loops. For more info |
159 | be described, which supports multiple event loops. For more info about |
103 | about various configuration options please have a look at the file |
160 | various configuration options please have a look at <strong>EMBED</strong> section in |
104 | <cite>README.embed</cite> in the libev distribution. If libev was configured without |
161 | this manual. If libev was configured without support for multiple event |
105 | support for multiple event loops, then all functions taking an initial |
162 | loops, then all functions taking an initial argument of name <code>loop</code> |
106 | argument of name <code>loop</code> (which is always of type <code>struct ev_loop *</code>) |
163 | (which is always of type <code>struct ev_loop *</code>) will not have this argument.</p> |
107 | will not have this argument.</p> |
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108 | |
164 | |
109 | </div> |
165 | </div> |
110 | <h1 id="TIME_REPRESENTATION">TIME REPRESENTATION</h1><p><a href="#TOP" class="toplink">Top</a></p> |
166 | <h1 id="TIME_REPRESENTATION">TIME REPRESENTATION</h1> |
111 | <div id="TIME_REPRESENTATION_CONTENT"> |
167 | <div id="TIME_REPRESENTATION_CONTENT"> |
112 | <p>Libev represents time as a single floating point number, representing the |
168 | <p>Libev represents time as a single floating point number, representing the |
113 | (fractional) number of seconds since the (POSIX) epoch (somewhere near |
169 | (fractional) number of seconds since the (POSIX) epoch (somewhere near |
114 | the beginning of 1970, details are complicated, don't ask). This type is |
170 | the beginning of 1970, details are complicated, don't ask). This type is |
115 | called <code>ev_tstamp</code>, which is what you should use too. It usually aliases |
171 | called <code>ev_tstamp</code>, which is what you should use too. It usually aliases |
116 | to the <code>double</code> type in C, and when you need to do any calculations on |
172 | to the <code>double</code> type in C, and when you need to do any calculations on |
117 | it, you should treat it as such.</p> |
173 | it, you should treat it as such.</p> |
118 | |
174 | |
119 | |
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120 | |
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121 | |
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122 | |
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123 | </div> |
175 | </div> |
124 | <h1 id="GLOBAL_FUNCTIONS">GLOBAL FUNCTIONS</h1><p><a href="#TOP" class="toplink">Top</a></p> |
176 | <h1 id="GLOBAL_FUNCTIONS">GLOBAL FUNCTIONS</h1> |
125 | <div id="GLOBAL_FUNCTIONS_CONTENT"> |
177 | <div id="GLOBAL_FUNCTIONS_CONTENT"> |
126 | <p>These functions can be called anytime, even before initialising the |
178 | <p>These functions can be called anytime, even before initialising the |
127 | library in any way.</p> |
179 | library in any way.</p> |
128 | <dl> |
180 | <dl> |
129 | <dt>ev_tstamp ev_time ()</dt> |
181 | <dt>ev_tstamp ev_time ()</dt> |
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142 | version of the library your program was compiled against.</p> |
194 | version of the library your program was compiled against.</p> |
143 | <p>Usually, it's a good idea to terminate if the major versions mismatch, |
195 | <p>Usually, it's a good idea to terminate if the major versions mismatch, |
144 | as this indicates an incompatible change. Minor versions are usually |
196 | as this indicates an incompatible change. Minor versions are usually |
145 | compatible to older versions, so a larger minor version alone is usually |
197 | compatible to older versions, so a larger minor version alone is usually |
146 | not a problem.</p> |
198 | not a problem.</p> |
147 | <p>Example: make sure we haven't accidentally been linked against the wrong |
199 | <p>Example: Make sure we haven't accidentally been linked against the wrong |
148 | version:</p> |
200 | version.</p> |
149 | <pre> assert (("libev version mismatch", |
201 | <pre> assert (("libev version mismatch", |
150 | ev_version_major () == EV_VERSION_MAJOR |
202 | ev_version_major () == EV_VERSION_MAJOR |
151 | && ev_version_minor () >= EV_VERSION_MINOR)); |
203 | && ev_version_minor () >= EV_VERSION_MINOR)); |
152 | |
204 | |
153 | </pre> |
205 | </pre> |
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183 | recommended ones.</p> |
235 | recommended ones.</p> |
184 | <p>See the description of <code>ev_embed</code> watchers for more info.</p> |
236 | <p>See the description of <code>ev_embed</code> watchers for more info.</p> |
185 | </dd> |
237 | </dd> |
186 | <dt>ev_set_allocator (void *(*cb)(void *ptr, long size))</dt> |
238 | <dt>ev_set_allocator (void *(*cb)(void *ptr, long size))</dt> |
187 | <dd> |
239 | <dd> |
188 | <p>Sets the allocation function to use (the prototype is similar to the |
240 | <p>Sets the allocation function to use (the prototype is similar - the |
189 | realloc C function, the semantics are identical). It is used to allocate |
241 | semantics is identical - to the realloc C function). It is used to |
190 | and free memory (no surprises here). If it returns zero when memory |
242 | allocate and free memory (no surprises here). If it returns zero when |
191 | needs to be allocated, the library might abort or take some potentially |
243 | memory needs to be allocated, the library might abort or take some |
192 | destructive action. The default is your system realloc function.</p> |
244 | potentially destructive action. The default is your system realloc |
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245 | function.</p> |
193 | <p>You could override this function in high-availability programs to, say, |
246 | <p>You could override this function in high-availability programs to, say, |
194 | free some memory if it cannot allocate memory, to use a special allocator, |
247 | free some memory if it cannot allocate memory, to use a special allocator, |
195 | or even to sleep a while and retry until some memory is available.</p> |
248 | or even to sleep a while and retry until some memory is available.</p> |
196 | <p>Example: replace the libev allocator with one that waits a bit and then |
249 | <p>Example: Replace the libev allocator with one that waits a bit and then |
197 | retries: better than mine).</p> |
250 | retries).</p> |
198 | <pre> static void * |
251 | <pre> static void * |
199 | persistent_realloc (void *ptr, long size) |
252 | persistent_realloc (void *ptr, size_t size) |
200 | { |
253 | { |
201 | for (;;) |
254 | for (;;) |
202 | { |
255 | { |
203 | void *newptr = realloc (ptr, size); |
256 | void *newptr = realloc (ptr, size); |
204 | |
257 | |
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221 | indicating the system call or subsystem causing the problem. If this |
274 | indicating the system call or subsystem causing the problem. If this |
222 | callback is set, then libev will expect it to remedy the sitution, no |
275 | callback is set, then libev will expect it to remedy the sitution, no |
223 | matter what, when it returns. That is, libev will generally retry the |
276 | matter what, when it returns. That is, libev will generally retry the |
224 | requested operation, or, if the condition doesn't go away, do bad stuff |
277 | requested operation, or, if the condition doesn't go away, do bad stuff |
225 | (such as abort).</p> |
278 | (such as abort).</p> |
226 | <p>Example: do the same thing as libev does internally:</p> |
279 | <p>Example: This is basically the same thing that libev does internally, too.</p> |
227 | <pre> static void |
280 | <pre> static void |
228 | fatal_error (const char *msg) |
281 | fatal_error (const char *msg) |
229 | { |
282 | { |
230 | perror (msg); |
283 | perror (msg); |
231 | abort (); |
284 | abort (); |
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237 | </pre> |
290 | </pre> |
238 | </dd> |
291 | </dd> |
239 | </dl> |
292 | </dl> |
240 | |
293 | |
241 | </div> |
294 | </div> |
242 | <h1 id="FUNCTIONS_CONTROLLING_THE_EVENT_LOOP">FUNCTIONS CONTROLLING THE EVENT LOOP</h1><p><a href="#TOP" class="toplink">Top</a></p> |
295 | <h1 id="FUNCTIONS_CONTROLLING_THE_EVENT_LOOP">FUNCTIONS CONTROLLING THE EVENT LOOP</h1> |
243 | <div id="FUNCTIONS_CONTROLLING_THE_EVENT_LOOP-2"> |
296 | <div id="FUNCTIONS_CONTROLLING_THE_EVENT_LOOP-2"> |
244 | <p>An event loop is described by a <code>struct ev_loop *</code>. The library knows two |
297 | <p>An event loop is described by a <code>struct ev_loop *</code>. The library knows two |
245 | types of such loops, the <i>default</i> loop, which supports signals and child |
298 | types of such loops, the <i>default</i> loop, which supports signals and child |
246 | events, and dynamically created loops which do not.</p> |
299 | events, and dynamically created loops which do not.</p> |
247 | <p>If you use threads, a common model is to run the default event loop |
300 | <p>If you use threads, a common model is to run the default event loop |
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276 | <code>LIBEV_FLAGS</code>. Otherwise (the default), this environment variable will |
329 | <code>LIBEV_FLAGS</code>. Otherwise (the default), this environment variable will |
277 | override the flags completely if it is found in the environment. This is |
330 | override the flags completely if it is found in the environment. This is |
278 | useful to try out specific backends to test their performance, or to work |
331 | useful to try out specific backends to test their performance, or to work |
279 | around bugs.</p> |
332 | around bugs.</p> |
280 | </dd> |
333 | </dd> |
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334 | <dt><code>EVFLAG_FORKCHECK</code></dt> |
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335 | <dd> |
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336 | <p>Instead of calling <code>ev_default_fork</code> or <code>ev_loop_fork</code> manually after |
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337 | a fork, you can also make libev check for a fork in each iteration by |
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338 | enabling this flag.</p> |
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339 | <p>This works by calling <code>getpid ()</code> on every iteration of the loop, |
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340 | and thus this might slow down your event loop if you do a lot of loop |
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341 | iterations and little real work, but is usually not noticeable (on my |
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342 | Linux system for example, <code>getpid</code> is actually a simple 5-insn sequence |
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343 | without a syscall and thus <i>very</i> fast, but my Linux system also has |
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344 | <code>pthread_atfork</code> which is even faster).</p> |
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345 | <p>The big advantage of this flag is that you can forget about fork (and |
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346 | forget about forgetting to tell libev about forking) when you use this |
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347 | flag.</p> |
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348 | <p>This flag setting cannot be overriden or specified in the <code>LIBEV_FLAGS</code> |
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349 | environment variable.</p> |
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350 | </dd> |
281 | <dt><code>EVBACKEND_SELECT</code> (value 1, portable select backend)</dt> |
351 | <dt><code>EVBACKEND_SELECT</code> (value 1, portable select backend)</dt> |
282 | <dd> |
352 | <dd> |
283 | <p>This is your standard select(2) backend. Not <i>completely</i> standard, as |
353 | <p>This is your standard select(2) backend. Not <i>completely</i> standard, as |
284 | libev tries to roll its own fd_set with no limits on the number of fds, |
354 | libev tries to roll its own fd_set with no limits on the number of fds, |
285 | but if that fails, expect a fairly low limit on the number of fds when |
355 | but if that fails, expect a fairly low limit on the number of fds when |
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367 | <dd> |
437 | <dd> |
368 | <p>Similar to <code>ev_default_loop</code>, but always creates a new event loop that is |
438 | <p>Similar to <code>ev_default_loop</code>, but always creates a new event loop that is |
369 | always distinct from the default loop. Unlike the default loop, it cannot |
439 | always distinct from the default loop. Unlike the default loop, it cannot |
370 | handle signal and child watchers, and attempts to do so will be greeted by |
440 | handle signal and child watchers, and attempts to do so will be greeted by |
371 | undefined behaviour (or a failed assertion if assertions are enabled).</p> |
441 | undefined behaviour (or a failed assertion if assertions are enabled).</p> |
372 | <p>Example: try to create a event loop that uses epoll and nothing else.</p> |
442 | <p>Example: Try to create a event loop that uses epoll and nothing else.</p> |
373 | <pre> struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
443 | <pre> struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
374 | if (!epoller) |
444 | if (!epoller) |
375 | fatal ("no epoll found here, maybe it hides under your chair"); |
445 | fatal ("no epoll found here, maybe it hides under your chair"); |
376 | |
446 | |
377 | </pre> |
447 | </pre> |
… | |
… | |
413 | <dt>ev_loop_fork (loop)</dt> |
483 | <dt>ev_loop_fork (loop)</dt> |
414 | <dd> |
484 | <dd> |
415 | <p>Like <code>ev_default_fork</code>, but acts on an event loop created by |
485 | <p>Like <code>ev_default_fork</code>, but acts on an event loop created by |
416 | <code>ev_loop_new</code>. Yes, you have to call this on every allocated event loop |
486 | <code>ev_loop_new</code>. Yes, you have to call this on every allocated event loop |
417 | after fork, and how you do this is entirely your own problem.</p> |
487 | after fork, and how you do this is entirely your own problem.</p> |
|
|
488 | </dd> |
|
|
489 | <dt>unsigned int ev_loop_count (loop)</dt> |
|
|
490 | <dd> |
|
|
491 | <p>Returns the count of loop iterations for the loop, which is identical to |
|
|
492 | the number of times libev did poll for new events. It starts at <code>0</code> and |
|
|
493 | happily wraps around with enough iterations.</p> |
|
|
494 | <p>This value can sometimes be useful as a generation counter of sorts (it |
|
|
495 | "ticks" the number of loop iterations), as it roughly corresponds with |
|
|
496 | <code>ev_prepare</code> and <code>ev_check</code> calls.</p> |
418 | </dd> |
497 | </dd> |
419 | <dt>unsigned int ev_backend (loop)</dt> |
498 | <dt>unsigned int ev_backend (loop)</dt> |
420 | <dd> |
499 | <dd> |
421 | <p>Returns one of the <code>EVBACKEND_*</code> flags indicating the event backend in |
500 | <p>Returns one of the <code>EVBACKEND_*</code> flags indicating the event backend in |
422 | use.</p> |
501 | use.</p> |
… | |
… | |
470 | be handled here by queueing them when their watcher gets executed. |
549 | be handled here by queueing them when their watcher gets executed. |
471 | - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
550 | - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
472 | were used, return, otherwise continue with step *. |
551 | were used, return, otherwise continue with step *. |
473 | |
552 | |
474 | </pre> |
553 | </pre> |
475 | <p>Example: queue some jobs and then loop until no events are outsanding |
554 | <p>Example: Queue some jobs and then loop until no events are outsanding |
476 | anymore.</p> |
555 | anymore.</p> |
477 | <pre> ... queue jobs here, make sure they register event watchers as long |
556 | <pre> ... queue jobs here, make sure they register event watchers as long |
478 | ... as they still have work to do (even an idle watcher will do..) |
557 | ... as they still have work to do (even an idle watcher will do..) |
479 | ev_loop (my_loop, 0); |
558 | ev_loop (my_loop, 0); |
480 | ... jobs done. yeah! |
559 | ... jobs done. yeah! |
… | |
… | |
499 | example, libev itself uses this for its internal signal pipe: It is not |
578 | example, libev itself uses this for its internal signal pipe: It is not |
500 | visible to the libev user and should not keep <code>ev_loop</code> from exiting if |
579 | visible to the libev user and should not keep <code>ev_loop</code> from exiting if |
501 | no event watchers registered by it are active. It is also an excellent |
580 | no event watchers registered by it are active. It is also an excellent |
502 | way to do this for generic recurring timers or from within third-party |
581 | way to do this for generic recurring timers or from within third-party |
503 | libraries. Just remember to <i>unref after start</i> and <i>ref before stop</i>.</p> |
582 | libraries. Just remember to <i>unref after start</i> and <i>ref before stop</i>.</p> |
504 | <p>Example: create a signal watcher, but keep it from keeping <code>ev_loop</code> |
583 | <p>Example: Create a signal watcher, but keep it from keeping <code>ev_loop</code> |
505 | running when nothing else is active.</p> |
584 | running when nothing else is active.</p> |
506 | <pre> struct dv_signal exitsig; |
585 | <pre> struct ev_signal exitsig; |
507 | ev_signal_init (&exitsig, sig_cb, SIGINT); |
586 | ev_signal_init (&exitsig, sig_cb, SIGINT); |
508 | ev_signal_start (myloop, &exitsig); |
587 | ev_signal_start (loop, &exitsig); |
509 | evf_unref (myloop); |
588 | evf_unref (loop); |
510 | |
589 | |
511 | </pre> |
590 | </pre> |
512 | <p>Example: for some weird reason, unregister the above signal handler again.</p> |
591 | <p>Example: For some weird reason, unregister the above signal handler again.</p> |
513 | <pre> ev_ref (myloop); |
592 | <pre> ev_ref (loop); |
514 | ev_signal_stop (myloop, &exitsig); |
593 | ev_signal_stop (loop, &exitsig); |
515 | |
594 | |
516 | </pre> |
595 | </pre> |
517 | </dd> |
596 | </dd> |
518 | </dl> |
597 | </dl> |
519 | |
598 | |
520 | |
599 | |
521 | |
600 | |
522 | |
601 | |
523 | |
602 | |
524 | </div> |
603 | </div> |
525 | <h1 id="ANATOMY_OF_A_WATCHER">ANATOMY OF A WATCHER</h1><p><a href="#TOP" class="toplink">Top</a></p> |
604 | <h1 id="ANATOMY_OF_A_WATCHER">ANATOMY OF A WATCHER</h1> |
526 | <div id="ANATOMY_OF_A_WATCHER_CONTENT"> |
605 | <div id="ANATOMY_OF_A_WATCHER_CONTENT"> |
527 | <p>A watcher is a structure that you create and register to record your |
606 | <p>A watcher is a structure that you create and register to record your |
528 | interest in some event. For instance, if you want to wait for STDIN to |
607 | interest in some event. For instance, if you want to wait for STDIN to |
529 | become readable, you would create an <code>ev_io</code> watcher for that:</p> |
608 | become readable, you would create an <code>ev_io</code> watcher for that:</p> |
530 | <pre> static void my_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
609 | <pre> static void my_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
… | |
… | |
606 | received events. Callbacks of both watcher types can start and stop as |
685 | received events. Callbacks of both watcher types can start and stop as |
607 | many watchers as they want, and all of them will be taken into account |
686 | many watchers as they want, and all of them will be taken into account |
608 | (for example, a <code>ev_prepare</code> watcher might start an idle watcher to keep |
687 | (for example, a <code>ev_prepare</code> watcher might start an idle watcher to keep |
609 | <code>ev_loop</code> from blocking).</p> |
688 | <code>ev_loop</code> from blocking).</p> |
610 | </dd> |
689 | </dd> |
|
|
690 | <dt><code>EV_EMBED</code></dt> |
|
|
691 | <dd> |
|
|
692 | <p>The embedded event loop specified in the <code>ev_embed</code> watcher needs attention.</p> |
|
|
693 | </dd> |
|
|
694 | <dt><code>EV_FORK</code></dt> |
|
|
695 | <dd> |
|
|
696 | <p>The event loop has been resumed in the child process after fork (see |
|
|
697 | <code>ev_fork</code>).</p> |
|
|
698 | </dd> |
611 | <dt><code>EV_ERROR</code></dt> |
699 | <dt><code>EV_ERROR</code></dt> |
612 | <dd> |
700 | <dd> |
613 | <p>An unspecified error has occured, the watcher has been stopped. This might |
701 | <p>An unspecified error has occured, the watcher has been stopped. This might |
614 | happen because the watcher could not be properly started because libev |
702 | happen because the watcher could not be properly started because libev |
615 | ran out of memory, a file descriptor was found to be closed or any other |
703 | ran out of memory, a file descriptor was found to be closed or any other |
… | |
… | |
681 | <dt>bool ev_is_pending (ev_TYPE *watcher)</dt> |
769 | <dt>bool ev_is_pending (ev_TYPE *watcher)</dt> |
682 | <dd> |
770 | <dd> |
683 | <p>Returns a true value iff the watcher is pending, (i.e. it has outstanding |
771 | <p>Returns a true value iff the watcher is pending, (i.e. it has outstanding |
684 | events but its callback has not yet been invoked). As long as a watcher |
772 | events but its callback has not yet been invoked). As long as a watcher |
685 | is pending (but not active) you must not call an init function on it (but |
773 | is pending (but not active) you must not call an init function on it (but |
686 | <code>ev_TYPE_set</code> is safe) and you must make sure the watcher is available to |
774 | <code>ev_TYPE_set</code> is safe), you must not change its priority, and you must |
687 | libev (e.g. you cnanot <code>free ()</code> it).</p> |
775 | make sure the watcher is available to libev (e.g. you cannot <code>free ()</code> |
|
|
776 | it).</p> |
688 | </dd> |
777 | </dd> |
689 | <dt>callback = ev_cb (ev_TYPE *watcher)</dt> |
778 | <dt>callback ev_cb (ev_TYPE *watcher)</dt> |
690 | <dd> |
779 | <dd> |
691 | <p>Returns the callback currently set on the watcher.</p> |
780 | <p>Returns the callback currently set on the watcher.</p> |
692 | </dd> |
781 | </dd> |
693 | <dt>ev_cb_set (ev_TYPE *watcher, callback)</dt> |
782 | <dt>ev_cb_set (ev_TYPE *watcher, callback)</dt> |
694 | <dd> |
783 | <dd> |
695 | <p>Change the callback. You can change the callback at virtually any time |
784 | <p>Change the callback. You can change the callback at virtually any time |
696 | (modulo threads).</p> |
785 | (modulo threads).</p> |
|
|
786 | </dd> |
|
|
787 | <dt>ev_set_priority (ev_TYPE *watcher, priority)</dt> |
|
|
788 | <dt>int ev_priority (ev_TYPE *watcher)</dt> |
|
|
789 | <dd> |
|
|
790 | <p>Set and query the priority of the watcher. The priority is a small |
|
|
791 | integer between <code>EV_MAXPRI</code> (default: <code>2</code>) and <code>EV_MINPRI</code> |
|
|
792 | (default: <code>-2</code>). Pending watchers with higher priority will be invoked |
|
|
793 | before watchers with lower priority, but priority will not keep watchers |
|
|
794 | from being executed (except for <code>ev_idle</code> watchers).</p> |
|
|
795 | <p>This means that priorities are <i>only</i> used for ordering callback |
|
|
796 | invocation after new events have been received. This is useful, for |
|
|
797 | example, to reduce latency after idling, or more often, to bind two |
|
|
798 | watchers on the same event and make sure one is called first.</p> |
|
|
799 | <p>If you need to suppress invocation when higher priority events are pending |
|
|
800 | you need to look at <code>ev_idle</code> watchers, which provide this functionality.</p> |
|
|
801 | <p>You <i>must not</i> change the priority of a watcher as long as it is active or |
|
|
802 | pending.</p> |
|
|
803 | <p>The default priority used by watchers when no priority has been set is |
|
|
804 | always <code>0</code>, which is supposed to not be too high and not be too low :).</p> |
|
|
805 | <p>Setting a priority outside the range of <code>EV_MINPRI</code> to <code>EV_MAXPRI</code> is |
|
|
806 | fine, as long as you do not mind that the priority value you query might |
|
|
807 | or might not have been adjusted to be within valid range.</p> |
|
|
808 | </dd> |
|
|
809 | <dt>ev_invoke (loop, ev_TYPE *watcher, int revents)</dt> |
|
|
810 | <dd> |
|
|
811 | <p>Invoke the <code>watcher</code> with the given <code>loop</code> and <code>revents</code>. Neither |
|
|
812 | <code>loop</code> nor <code>revents</code> need to be valid as long as the watcher callback |
|
|
813 | can deal with that fact.</p> |
|
|
814 | </dd> |
|
|
815 | <dt>int ev_clear_pending (loop, ev_TYPE *watcher)</dt> |
|
|
816 | <dd> |
|
|
817 | <p>If the watcher is pending, this function returns clears its pending status |
|
|
818 | and returns its <code>revents</code> bitset (as if its callback was invoked). If the |
|
|
819 | watcher isn't pending it does nothing and returns <code>0</code>.</p> |
697 | </dd> |
820 | </dd> |
698 | </dl> |
821 | </dl> |
699 | |
822 | |
700 | |
823 | |
701 | |
824 | |
… | |
… | |
726 | struct my_io *w = (struct my_io *)w_; |
849 | struct my_io *w = (struct my_io *)w_; |
727 | ... |
850 | ... |
728 | } |
851 | } |
729 | |
852 | |
730 | </pre> |
853 | </pre> |
731 | <p>More interesting and less C-conformant ways of catsing your callback type |
854 | <p>More interesting and less C-conformant ways of casting your callback type |
732 | have been omitted....</p> |
855 | instead have been omitted.</p> |
|
|
856 | <p>Another common scenario is having some data structure with multiple |
|
|
857 | watchers:</p> |
|
|
858 | <pre> struct my_biggy |
|
|
859 | { |
|
|
860 | int some_data; |
|
|
861 | ev_timer t1; |
|
|
862 | ev_timer t2; |
|
|
863 | } |
733 | |
864 | |
|
|
865 | </pre> |
|
|
866 | <p>In this case getting the pointer to <code>my_biggy</code> is a bit more complicated, |
|
|
867 | you need to use <code>offsetof</code>:</p> |
|
|
868 | <pre> #include <stddef.h> |
734 | |
869 | |
|
|
870 | static void |
|
|
871 | t1_cb (EV_P_ struct ev_timer *w, int revents) |
|
|
872 | { |
|
|
873 | struct my_biggy big = (struct my_biggy * |
|
|
874 | (((char *)w) - offsetof (struct my_biggy, t1)); |
|
|
875 | } |
735 | |
876 | |
|
|
877 | static void |
|
|
878 | t2_cb (EV_P_ struct ev_timer *w, int revents) |
|
|
879 | { |
|
|
880 | struct my_biggy big = (struct my_biggy * |
|
|
881 | (((char *)w) - offsetof (struct my_biggy, t2)); |
|
|
882 | } |
736 | |
883 | |
737 | |
884 | |
|
|
885 | |
|
|
886 | |
|
|
887 | </pre> |
|
|
888 | |
738 | </div> |
889 | </div> |
739 | <h1 id="WATCHER_TYPES">WATCHER TYPES</h1><p><a href="#TOP" class="toplink">Top</a></p> |
890 | <h1 id="WATCHER_TYPES">WATCHER TYPES</h1> |
740 | <div id="WATCHER_TYPES_CONTENT"> |
891 | <div id="WATCHER_TYPES_CONTENT"> |
741 | <p>This section describes each watcher in detail, but will not repeat |
892 | <p>This section describes each watcher in detail, but will not repeat |
742 | information given in the last section. Any initialisation/set macros, |
893 | information given in the last section. Any initialisation/set macros, |
743 | functions and members specific to the watcher type are explained.</p> |
894 | functions and members specific to the watcher type are explained.</p> |
744 | <p>Members are additionally marked with either <i>[read-only]</i>, meaning that, |
895 | <p>Members are additionally marked with either <i>[read-only]</i>, meaning that, |
… | |
… | |
784 | this situation even with a relatively standard program structure. Thus |
935 | this situation even with a relatively standard program structure. Thus |
785 | it is best to always use non-blocking I/O: An extra <code>read</code>(2) returning |
936 | it is best to always use non-blocking I/O: An extra <code>read</code>(2) returning |
786 | <code>EAGAIN</code> is far preferable to a program hanging until some data arrives.</p> |
937 | <code>EAGAIN</code> is far preferable to a program hanging until some data arrives.</p> |
787 | <p>If you cannot run the fd in non-blocking mode (for example you should not |
938 | <p>If you cannot run the fd in non-blocking mode (for example you should not |
788 | play around with an Xlib connection), then you have to seperately re-test |
939 | play around with an Xlib connection), then you have to seperately re-test |
789 | wether a file descriptor is really ready with a known-to-be good interface |
940 | whether a file descriptor is really ready with a known-to-be good interface |
790 | such as poll (fortunately in our Xlib example, Xlib already does this on |
941 | such as poll (fortunately in our Xlib example, Xlib already does this on |
791 | its own, so its quite safe to use).</p> |
942 | its own, so its quite safe to use).</p> |
792 | <dl> |
943 | <dl> |
793 | <dt>ev_io_init (ev_io *, callback, int fd, int events)</dt> |
944 | <dt>ev_io_init (ev_io *, callback, int fd, int events)</dt> |
794 | <dt>ev_io_set (ev_io *, int fd, int events)</dt> |
945 | <dt>ev_io_set (ev_io *, int fd, int events)</dt> |
… | |
… | |
804 | <dt>int events [read-only]</dt> |
955 | <dt>int events [read-only]</dt> |
805 | <dd> |
956 | <dd> |
806 | <p>The events being watched.</p> |
957 | <p>The events being watched.</p> |
807 | </dd> |
958 | </dd> |
808 | </dl> |
959 | </dl> |
809 | <p>Example: call <code>stdin_readable_cb</code> when STDIN_FILENO has become, well |
960 | <p>Example: Call <code>stdin_readable_cb</code> when STDIN_FILENO has become, well |
810 | readable, but only once. Since it is likely line-buffered, you could |
961 | readable, but only once. Since it is likely line-buffered, you could |
811 | attempt to read a whole line in the callback:</p> |
962 | attempt to read a whole line in the callback.</p> |
812 | <pre> static void |
963 | <pre> static void |
813 | stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
964 | stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
814 | { |
965 | { |
815 | ev_io_stop (loop, w); |
966 | ev_io_stop (loop, w); |
816 | .. read from stdin here (or from w->fd) and haqndle any I/O errors |
967 | .. read from stdin here (or from w->fd) and haqndle any I/O errors |
… | |
… | |
865 | </dd> |
1016 | </dd> |
866 | <dt>ev_timer_again (loop)</dt> |
1017 | <dt>ev_timer_again (loop)</dt> |
867 | <dd> |
1018 | <dd> |
868 | <p>This will act as if the timer timed out and restart it again if it is |
1019 | <p>This will act as if the timer timed out and restart it again if it is |
869 | repeating. The exact semantics are:</p> |
1020 | repeating. The exact semantics are:</p> |
|
|
1021 | <p>If the timer is pending, its pending status is cleared.</p> |
870 | <p>If the timer is started but nonrepeating, stop it.</p> |
1022 | <p>If the timer is started but nonrepeating, stop it (as if it timed out).</p> |
871 | <p>If the timer is repeating, either start it if necessary (with the repeat |
1023 | <p>If the timer is repeating, either start it if necessary (with the |
872 | value), or reset the running timer to the repeat value.</p> |
1024 | <code>repeat</code> value), or reset the running timer to the <code>repeat</code> value.</p> |
873 | <p>This sounds a bit complicated, but here is a useful and typical |
1025 | <p>This sounds a bit complicated, but here is a useful and typical |
874 | example: Imagine you have a tcp connection and you want a so-called |
1026 | example: Imagine you have a tcp connection and you want a so-called idle |
875 | idle timeout, that is, you want to be called when there have been, |
1027 | timeout, that is, you want to be called when there have been, say, 60 |
876 | say, 60 seconds of inactivity on the socket. The easiest way to do |
1028 | seconds of inactivity on the socket. The easiest way to do this is to |
877 | this is to configure an <code>ev_timer</code> with <code>after</code>=<code>repeat</code>=<code>60</code> and calling |
1029 | configure an <code>ev_timer</code> with a <code>repeat</code> value of <code>60</code> and then call |
878 | <code>ev_timer_again</code> each time you successfully read or write some data. If |
1030 | <code>ev_timer_again</code> each time you successfully read or write some data. If |
879 | you go into an idle state where you do not expect data to travel on the |
1031 | you go into an idle state where you do not expect data to travel on the |
880 | socket, you can stop the timer, and again will automatically restart it if |
1032 | socket, you can <code>ev_timer_stop</code> the timer, and <code>ev_timer_again</code> will |
881 | need be.</p> |
1033 | automatically restart it if need be.</p> |
882 | <p>You can also ignore the <code>after</code> value and <code>ev_timer_start</code> altogether |
1034 | <p>That means you can ignore the <code>after</code> value and <code>ev_timer_start</code> |
883 | and only ever use the <code>repeat</code> value:</p> |
1035 | altogether and only ever use the <code>repeat</code> value and <code>ev_timer_again</code>:</p> |
884 | <pre> ev_timer_init (timer, callback, 0., 5.); |
1036 | <pre> ev_timer_init (timer, callback, 0., 5.); |
885 | ev_timer_again (loop, timer); |
1037 | ev_timer_again (loop, timer); |
886 | ... |
1038 | ... |
887 | timer->again = 17.; |
1039 | timer->again = 17.; |
888 | ev_timer_again (loop, timer); |
1040 | ev_timer_again (loop, timer); |
889 | ... |
1041 | ... |
890 | timer->again = 10.; |
1042 | timer->again = 10.; |
891 | ev_timer_again (loop, timer); |
1043 | ev_timer_again (loop, timer); |
892 | |
1044 | |
893 | </pre> |
1045 | </pre> |
894 | <p>This is more efficient then stopping/starting the timer eahc time you want |
1046 | <p>This is more slightly efficient then stopping/starting the timer each time |
895 | to modify its timeout value.</p> |
1047 | you want to modify its timeout value.</p> |
896 | </dd> |
1048 | </dd> |
897 | <dt>ev_tstamp repeat [read-write]</dt> |
1049 | <dt>ev_tstamp repeat [read-write]</dt> |
898 | <dd> |
1050 | <dd> |
899 | <p>The current <code>repeat</code> value. Will be used each time the watcher times out |
1051 | <p>The current <code>repeat</code> value. Will be used each time the watcher times out |
900 | or <code>ev_timer_again</code> is called and determines the next timeout (if any), |
1052 | or <code>ev_timer_again</code> is called and determines the next timeout (if any), |
901 | which is also when any modifications are taken into account.</p> |
1053 | which is also when any modifications are taken into account.</p> |
902 | </dd> |
1054 | </dd> |
903 | </dl> |
1055 | </dl> |
904 | <p>Example: create a timer that fires after 60 seconds.</p> |
1056 | <p>Example: Create a timer that fires after 60 seconds.</p> |
905 | <pre> static void |
1057 | <pre> static void |
906 | one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1058 | one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
907 | { |
1059 | { |
908 | .. one minute over, w is actually stopped right here |
1060 | .. one minute over, w is actually stopped right here |
909 | } |
1061 | } |
… | |
… | |
911 | struct ev_timer mytimer; |
1063 | struct ev_timer mytimer; |
912 | ev_timer_init (&mytimer, one_minute_cb, 60., 0.); |
1064 | ev_timer_init (&mytimer, one_minute_cb, 60., 0.); |
913 | ev_timer_start (loop, &mytimer); |
1065 | ev_timer_start (loop, &mytimer); |
914 | |
1066 | |
915 | </pre> |
1067 | </pre> |
916 | <p>Example: create a timeout timer that times out after 10 seconds of |
1068 | <p>Example: Create a timeout timer that times out after 10 seconds of |
917 | inactivity.</p> |
1069 | inactivity.</p> |
918 | <pre> static void |
1070 | <pre> static void |
919 | timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1071 | timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
920 | { |
1072 | { |
921 | .. ten seconds without any activity |
1073 | .. ten seconds without any activity |
… | |
… | |
1037 | <p>The current reschedule callback, or <code>0</code>, if this functionality is |
1189 | <p>The current reschedule callback, or <code>0</code>, if this functionality is |
1038 | switched off. Can be changed any time, but changes only take effect when |
1190 | switched off. Can be changed any time, but changes only take effect when |
1039 | the periodic timer fires or <code>ev_periodic_again</code> is being called.</p> |
1191 | the periodic timer fires or <code>ev_periodic_again</code> is being called.</p> |
1040 | </dd> |
1192 | </dd> |
1041 | </dl> |
1193 | </dl> |
1042 | <p>Example: call a callback every hour, or, more precisely, whenever the |
1194 | <p>Example: Call a callback every hour, or, more precisely, whenever the |
1043 | system clock is divisible by 3600. The callback invocation times have |
1195 | system clock is divisible by 3600. The callback invocation times have |
1044 | potentially a lot of jittering, but good long-term stability.</p> |
1196 | potentially a lot of jittering, but good long-term stability.</p> |
1045 | <pre> static void |
1197 | <pre> static void |
1046 | clock_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
1198 | clock_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
1047 | { |
1199 | { |
… | |
… | |
1051 | struct ev_periodic hourly_tick; |
1203 | struct ev_periodic hourly_tick; |
1052 | ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); |
1204 | ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); |
1053 | ev_periodic_start (loop, &hourly_tick); |
1205 | ev_periodic_start (loop, &hourly_tick); |
1054 | |
1206 | |
1055 | </pre> |
1207 | </pre> |
1056 | <p>Example: the same as above, but use a reschedule callback to do it:</p> |
1208 | <p>Example: The same as above, but use a reschedule callback to do it:</p> |
1057 | <pre> #include <math.h> |
1209 | <pre> #include <math.h> |
1058 | |
1210 | |
1059 | static ev_tstamp |
1211 | static ev_tstamp |
1060 | my_scheduler_cb (struct ev_periodic *w, ev_tstamp now) |
1212 | my_scheduler_cb (struct ev_periodic *w, ev_tstamp now) |
1061 | { |
1213 | { |
… | |
… | |
1063 | } |
1215 | } |
1064 | |
1216 | |
1065 | ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); |
1217 | ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); |
1066 | |
1218 | |
1067 | </pre> |
1219 | </pre> |
1068 | <p>Example: call a callback every hour, starting now:</p> |
1220 | <p>Example: Call a callback every hour, starting now:</p> |
1069 | <pre> struct ev_periodic hourly_tick; |
1221 | <pre> struct ev_periodic hourly_tick; |
1070 | ev_periodic_init (&hourly_tick, clock_cb, |
1222 | ev_periodic_init (&hourly_tick, clock_cb, |
1071 | fmod (ev_now (loop), 3600.), 3600., 0); |
1223 | fmod (ev_now (loop), 3600.), 3600., 0); |
1072 | ev_periodic_start (loop, &hourly_tick); |
1224 | ev_periodic_start (loop, &hourly_tick); |
1073 | |
1225 | |
… | |
… | |
1134 | <dd> |
1286 | <dd> |
1135 | <p>The process exit/trace status caused by <code>rpid</code> (see your systems |
1287 | <p>The process exit/trace status caused by <code>rpid</code> (see your systems |
1136 | <code>waitpid</code> and <code>sys/wait.h</code> documentation for details).</p> |
1288 | <code>waitpid</code> and <code>sys/wait.h</code> documentation for details).</p> |
1137 | </dd> |
1289 | </dd> |
1138 | </dl> |
1290 | </dl> |
1139 | <p>Example: try to exit cleanly on SIGINT and SIGTERM.</p> |
1291 | <p>Example: Try to exit cleanly on SIGINT and SIGTERM.</p> |
1140 | <pre> static void |
1292 | <pre> static void |
1141 | sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
1293 | sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
1142 | { |
1294 | { |
1143 | ev_unloop (loop, EVUNLOOP_ALL); |
1295 | ev_unloop (loop, EVUNLOOP_ALL); |
1144 | } |
1296 | } |
… | |
… | |
1161 | <p>The path does not need to exist: changing from "path exists" to "path does |
1313 | <p>The path does not need to exist: changing from "path exists" to "path does |
1162 | not exist" is a status change like any other. The condition "path does |
1314 | not exist" is a status change like any other. The condition "path does |
1163 | not exist" is signified by the <code>st_nlink</code> field being zero (which is |
1315 | not exist" is signified by the <code>st_nlink</code> field being zero (which is |
1164 | otherwise always forced to be at least one) and all the other fields of |
1316 | otherwise always forced to be at least one) and all the other fields of |
1165 | the stat buffer having unspecified contents.</p> |
1317 | the stat buffer having unspecified contents.</p> |
|
|
1318 | <p>The path <i>should</i> be absolute and <i>must not</i> end in a slash. If it is |
|
|
1319 | relative and your working directory changes, the behaviour is undefined.</p> |
1166 | <p>Since there is no standard to do this, the portable implementation simply |
1320 | <p>Since there is no standard to do this, the portable implementation simply |
1167 | calls <code>stat (2)</code> regulalry on the path to see if it changed somehow. You |
1321 | calls <code>stat (2)</code> regularly on the path to see if it changed somehow. You |
1168 | can specify a recommended polling interval for this case. If you specify |
1322 | can specify a recommended polling interval for this case. If you specify |
1169 | a polling interval of <code>0</code> (highly recommended!) then a <i>suitable, |
1323 | a polling interval of <code>0</code> (highly recommended!) then a <i>suitable, |
1170 | unspecified default</i> value will be used (which you can expect to be around |
1324 | unspecified default</i> value will be used (which you can expect to be around |
1171 | five seconds, although this might change dynamically). Libev will also |
1325 | five seconds, although this might change dynamically). Libev will also |
1172 | impose a minimum interval which is currently around <code>0.1</code>, but thats |
1326 | impose a minimum interval which is currently around <code>0.1</code>, but thats |
1173 | usually overkill.</p> |
1327 | usually overkill.</p> |
1174 | <p>This watcher type is not meant for massive numbers of stat watchers, |
1328 | <p>This watcher type is not meant for massive numbers of stat watchers, |
1175 | as even with OS-supported change notifications, this can be |
1329 | as even with OS-supported change notifications, this can be |
1176 | resource-intensive.</p> |
1330 | resource-intensive.</p> |
1177 | <p>At the time of this writing, no specific OS backends are implemented, but |
1331 | <p>At the time of this writing, only the Linux inotify interface is |
1178 | if demand increases, at least a kqueue and inotify backend will be added.</p> |
1332 | implemented (implementing kqueue support is left as an exercise for the |
|
|
1333 | reader). Inotify will be used to give hints only and should not change the |
|
|
1334 | semantics of <code>ev_stat</code> watchers, which means that libev sometimes needs |
|
|
1335 | to fall back to regular polling again even with inotify, but changes are |
|
|
1336 | usually detected immediately, and if the file exists there will be no |
|
|
1337 | polling.</p> |
1179 | <dl> |
1338 | <dl> |
1180 | <dt>ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)</dt> |
1339 | <dt>ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)</dt> |
1181 | <dt>ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)</dt> |
1340 | <dt>ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)</dt> |
1182 | <dd> |
1341 | <dd> |
1183 | <p>Configures the watcher to wait for status changes of the given |
1342 | <p>Configures the watcher to wait for status changes of the given |
… | |
… | |
1246 | </pre> |
1405 | </pre> |
1247 | |
1406 | |
1248 | </div> |
1407 | </div> |
1249 | <h2 id="code_ev_idle_code_when_you_ve_got_no"><code>ev_idle</code> - when you've got nothing better to do...</h2> |
1408 | <h2 id="code_ev_idle_code_when_you_ve_got_no"><code>ev_idle</code> - when you've got nothing better to do...</h2> |
1250 | <div id="code_ev_idle_code_when_you_ve_got_no-2"> |
1409 | <div id="code_ev_idle_code_when_you_ve_got_no-2"> |
1251 | <p>Idle watchers trigger events when there are no other events are pending |
1410 | <p>Idle watchers trigger events when no other events of the same or higher |
1252 | (prepare, check and other idle watchers do not count). That is, as long |
1411 | priority are pending (prepare, check and other idle watchers do not |
1253 | as your process is busy handling sockets or timeouts (or even signals, |
1412 | count).</p> |
1254 | imagine) it will not be triggered. But when your process is idle all idle |
1413 | <p>That is, as long as your process is busy handling sockets or timeouts |
1255 | watchers are being called again and again, once per event loop iteration - |
1414 | (or even signals, imagine) of the same or higher priority it will not be |
|
|
1415 | triggered. But when your process is idle (or only lower-priority watchers |
|
|
1416 | are pending), the idle watchers are being called once per event loop |
1256 | until stopped, that is, or your process receives more events and becomes |
1417 | iteration - until stopped, that is, or your process receives more events |
1257 | busy.</p> |
1418 | and becomes busy again with higher priority stuff.</p> |
1258 | <p>The most noteworthy effect is that as long as any idle watchers are |
1419 | <p>The most noteworthy effect is that as long as any idle watchers are |
1259 | active, the process will not block when waiting for new events.</p> |
1420 | active, the process will not block when waiting for new events.</p> |
1260 | <p>Apart from keeping your process non-blocking (which is a useful |
1421 | <p>Apart from keeping your process non-blocking (which is a useful |
1261 | effect on its own sometimes), idle watchers are a good place to do |
1422 | effect on its own sometimes), idle watchers are a good place to do |
1262 | "pseudo-background processing", or delay processing stuff to after the |
1423 | "pseudo-background processing", or delay processing stuff to after the |
… | |
… | |
1267 | <p>Initialises and configures the idle watcher - it has no parameters of any |
1428 | <p>Initialises and configures the idle watcher - it has no parameters of any |
1268 | kind. There is a <code>ev_idle_set</code> macro, but using it is utterly pointless, |
1429 | kind. There is a <code>ev_idle_set</code> macro, but using it is utterly pointless, |
1269 | believe me.</p> |
1430 | believe me.</p> |
1270 | </dd> |
1431 | </dd> |
1271 | </dl> |
1432 | </dl> |
1272 | <p>Example: dynamically allocate an <code>ev_idle</code>, start it, and in the |
1433 | <p>Example: Dynamically allocate an <code>ev_idle</code> watcher, start it, and in the |
1273 | callback, free it. Alos, use no error checking, as usual.</p> |
1434 | callback, free it. Also, use no error checking, as usual.</p> |
1274 | <pre> static void |
1435 | <pre> static void |
1275 | idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
1436 | idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
1276 | { |
1437 | { |
1277 | free (w); |
1438 | free (w); |
1278 | // now do something you wanted to do when the program has |
1439 | // now do something you wanted to do when the program has |
… | |
… | |
1352 | |
1513 | |
1353 | // create io watchers for each fd and a timer before blocking |
1514 | // create io watchers for each fd and a timer before blocking |
1354 | static void |
1515 | static void |
1355 | adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
1516 | adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
1356 | { |
1517 | { |
1357 | int timeout = 3600000;truct pollfd fds [nfd]; |
1518 | int timeout = 3600000; |
|
|
1519 | struct pollfd fds [nfd]; |
1358 | // actual code will need to loop here and realloc etc. |
1520 | // actual code will need to loop here and realloc etc. |
1359 | adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
1521 | adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
1360 | |
1522 | |
1361 | /* the callback is illegal, but won't be called as we stop during check */ |
1523 | /* the callback is illegal, but won't be called as we stop during check */ |
1362 | ev_timer_init (&tw, 0, timeout * 1e-3); |
1524 | ev_timer_init (&tw, 0, timeout * 1e-3); |
… | |
… | |
1480 | |
1642 | |
1481 | |
1643 | |
1482 | |
1644 | |
1483 | |
1645 | |
1484 | </div> |
1646 | </div> |
1485 | <h1 id="OTHER_FUNCTIONS">OTHER FUNCTIONS</h1><p><a href="#TOP" class="toplink">Top</a></p> |
1647 | <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> |
|
|
1648 | <div id="code_ev_fork_code_the_audacity_to_re-2"> |
|
|
1649 | <p>Fork watchers are called when a <code>fork ()</code> was detected (usually because |
|
|
1650 | whoever is a good citizen cared to tell libev about it by calling |
|
|
1651 | <code>ev_default_fork</code> or <code>ev_loop_fork</code>). The invocation is done before the |
|
|
1652 | event loop blocks next and before <code>ev_check</code> watchers are being called, |
|
|
1653 | and only in the child after the fork. If whoever good citizen calling |
|
|
1654 | <code>ev_default_fork</code> cheats and calls it in the wrong process, the fork |
|
|
1655 | handlers will be invoked, too, of course.</p> |
|
|
1656 | <dl> |
|
|
1657 | <dt>ev_fork_init (ev_signal *, callback)</dt> |
|
|
1658 | <dd> |
|
|
1659 | <p>Initialises and configures the fork watcher - it has no parameters of any |
|
|
1660 | kind. There is a <code>ev_fork_set</code> macro, but using it is utterly pointless, |
|
|
1661 | believe me.</p> |
|
|
1662 | </dd> |
|
|
1663 | </dl> |
|
|
1664 | |
|
|
1665 | |
|
|
1666 | |
|
|
1667 | |
|
|
1668 | |
|
|
1669 | </div> |
|
|
1670 | <h1 id="OTHER_FUNCTIONS">OTHER FUNCTIONS</h1> |
1486 | <div id="OTHER_FUNCTIONS_CONTENT"> |
1671 | <div id="OTHER_FUNCTIONS_CONTENT"> |
1487 | <p>There are some other functions of possible interest. Described. Here. Now.</p> |
1672 | <p>There are some other functions of possible interest. Described. Here. Now.</p> |
1488 | <dl> |
1673 | <dl> |
1489 | <dt>ev_once (loop, int fd, int events, ev_tstamp timeout, callback)</dt> |
1674 | <dt>ev_once (loop, int fd, int events, ev_tstamp timeout, callback)</dt> |
1490 | <dd> |
1675 | <dd> |
… | |
… | |
1537 | |
1722 | |
1538 | |
1723 | |
1539 | |
1724 | |
1540 | |
1725 | |
1541 | </div> |
1726 | </div> |
1542 | <h1 id="LIBEVENT_EMULATION">LIBEVENT EMULATION</h1><p><a href="#TOP" class="toplink">Top</a></p> |
1727 | <h1 id="LIBEVENT_EMULATION">LIBEVENT EMULATION</h1> |
1543 | <div id="LIBEVENT_EMULATION_CONTENT"> |
1728 | <div id="LIBEVENT_EMULATION_CONTENT"> |
1544 | <p>Libev offers a compatibility emulation layer for libevent. It cannot |
1729 | <p>Libev offers a compatibility emulation layer for libevent. It cannot |
1545 | emulate the internals of libevent, so here are some usage hints:</p> |
1730 | emulate the internals of libevent, so here are some usage hints:</p> |
1546 | <dl> |
1731 | <dl> |
1547 | <dt>* Use it by including <event.h>, as usual.</dt> |
1732 | <dt>* Use it by including <event.h>, as usual.</dt> |
… | |
… | |
1557 | <dt>* The libev emulation is <i>not</i> ABI compatible to libevent, you need |
1742 | <dt>* The libev emulation is <i>not</i> ABI compatible to libevent, you need |
1558 | to use the libev header file and library.</dt> |
1743 | to use the libev header file and library.</dt> |
1559 | </dl> |
1744 | </dl> |
1560 | |
1745 | |
1561 | </div> |
1746 | </div> |
1562 | <h1 id="C_SUPPORT">C++ SUPPORT</h1><p><a href="#TOP" class="toplink">Top</a></p> |
1747 | <h1 id="C_SUPPORT">C++ SUPPORT</h1> |
1563 | <div id="C_SUPPORT_CONTENT"> |
1748 | <div id="C_SUPPORT_CONTENT"> |
1564 | <p>Libev comes with some simplistic wrapper classes for C++ that mainly allow |
1749 | <p>Libev comes with some simplistic wrapper classes for C++ that mainly allow |
1565 | you to use some convinience methods to start/stop watchers and also change |
1750 | you to use some convinience methods to start/stop watchers and also change |
1566 | the callback model to a model using method callbacks on objects.</p> |
1751 | the callback model to a model using method callbacks on objects.</p> |
1567 | <p>To use it,</p> |
1752 | <p>To use it,</p> |
1568 | <pre> #include <ev++.h> |
1753 | <pre> #include <ev++.h> |
1569 | |
1754 | |
1570 | </pre> |
1755 | </pre> |
1571 | <p>(it is not installed by default). This automatically includes <cite>ev.h</cite> |
1756 | <p>This automatically includes <cite>ev.h</cite> and puts all of its definitions (many |
1572 | and puts all of its definitions (many of them macros) into the global |
1757 | of them macros) into the global namespace. All C++ specific things are |
1573 | namespace. All C++ specific things are put into the <code>ev</code> namespace.</p> |
1758 | put into the <code>ev</code> namespace. It should support all the same embedding |
1574 | <p>It should support all the same embedding options as <cite>ev.h</cite>, most notably |
1759 | options as <cite>ev.h</cite>, most notably <code>EV_MULTIPLICITY</code>.</p> |
1575 | <code>EV_MULTIPLICITY</code>.</p> |
1760 | <p>Care has been taken to keep the overhead low. The only data member the C++ |
|
|
1761 | classes add (compared to plain C-style watchers) is the event loop pointer |
|
|
1762 | that the watcher is associated with (or no additional members at all if |
|
|
1763 | you disable <code>EV_MULTIPLICITY</code> when embedding libev).</p> |
|
|
1764 | <p>Currently, functions, and static and non-static member functions can be |
|
|
1765 | used as callbacks. Other types should be easy to add as long as they only |
|
|
1766 | need one additional pointer for context. If you need support for other |
|
|
1767 | types of functors please contact the author (preferably after implementing |
|
|
1768 | it).</p> |
1576 | <p>Here is a list of things available in the <code>ev</code> namespace:</p> |
1769 | <p>Here is a list of things available in the <code>ev</code> namespace:</p> |
1577 | <dl> |
1770 | <dl> |
1578 | <dt><code>ev::READ</code>, <code>ev::WRITE</code> etc.</dt> |
1771 | <dt><code>ev::READ</code>, <code>ev::WRITE</code> etc.</dt> |
1579 | <dd> |
1772 | <dd> |
1580 | <p>These are just enum values with the same values as the <code>EV_READ</code> etc. |
1773 | <p>These are just enum values with the same values as the <code>EV_READ</code> etc. |
… | |
… | |
1591 | which is called <code>ev::sig</code> to avoid clashes with the <code>signal</code> macro |
1784 | which is called <code>ev::sig</code> to avoid clashes with the <code>signal</code> macro |
1592 | defines by many implementations.</p> |
1785 | defines by many implementations.</p> |
1593 | <p>All of those classes have these methods:</p> |
1786 | <p>All of those classes have these methods:</p> |
1594 | <p> |
1787 | <p> |
1595 | <dl> |
1788 | <dl> |
1596 | <dt>ev::TYPE::TYPE (object *, object::method *)</dt> |
1789 | <dt>ev::TYPE::TYPE ()</dt> |
1597 | <dt>ev::TYPE::TYPE (object *, object::method *, struct ev_loop *)</dt> |
1790 | <dt>ev::TYPE::TYPE (struct ev_loop *)</dt> |
1598 | <dt>ev::TYPE::~TYPE</dt> |
1791 | <dt>ev::TYPE::~TYPE</dt> |
1599 | <dd> |
1792 | <dd> |
1600 | <p>The constructor takes a pointer to an object and a method pointer to |
1793 | <p>The constructor (optionally) takes an event loop to associate the watcher |
1601 | the event handler callback to call in this class. The constructor calls |
1794 | with. If it is omitted, it will use <code>EV_DEFAULT</code>.</p> |
1602 | <code>ev_init</code> for you, which means you have to call the <code>set</code> method |
1795 | <p>The constructor calls <code>ev_init</code> for you, which means you have to call the |
1603 | before starting it. If you do not specify a loop then the constructor |
1796 | <code>set</code> method before starting it.</p> |
1604 | automatically associates the default loop with this watcher.</p> |
1797 | <p>It will not set a callback, however: You have to call the templated <code>set</code> |
|
|
1798 | method to set a callback before you can start the watcher.</p> |
|
|
1799 | <p>(The reason why you have to use a method is a limitation in C++ which does |
|
|
1800 | not allow explicit template arguments for constructors).</p> |
1605 | <p>The destructor automatically stops the watcher if it is active.</p> |
1801 | <p>The destructor automatically stops the watcher if it is active.</p> |
|
|
1802 | </dd> |
|
|
1803 | <dt>w->set<class, &class::method> (object *)</dt> |
|
|
1804 | <dd> |
|
|
1805 | <p>This method sets the callback method to call. The method has to have a |
|
|
1806 | signature of <code>void (*)(ev_TYPE &, int)</code>, it receives the watcher as |
|
|
1807 | first argument and the <code>revents</code> as second. The object must be given as |
|
|
1808 | parameter and is stored in the <code>data</code> member of the watcher.</p> |
|
|
1809 | <p>This method synthesizes efficient thunking code to call your method from |
|
|
1810 | the C callback that libev requires. If your compiler can inline your |
|
|
1811 | callback (i.e. it is visible to it at the place of the <code>set</code> call and |
|
|
1812 | your compiler is good :), then the method will be fully inlined into the |
|
|
1813 | thunking function, making it as fast as a direct C callback.</p> |
|
|
1814 | <p>Example: simple class declaration and watcher initialisation</p> |
|
|
1815 | <pre> struct myclass |
|
|
1816 | { |
|
|
1817 | void io_cb (ev::io &w, int revents) { } |
|
|
1818 | } |
|
|
1819 | |
|
|
1820 | myclass obj; |
|
|
1821 | ev::io iow; |
|
|
1822 | iow.set <myclass, &myclass::io_cb> (&obj); |
|
|
1823 | |
|
|
1824 | </pre> |
|
|
1825 | </dd> |
|
|
1826 | <dt>w->set<function> (void *data = 0)</dt> |
|
|
1827 | <dd> |
|
|
1828 | <p>Also sets a callback, but uses a static method or plain function as |
|
|
1829 | callback. The optional <code>data</code> argument will be stored in the watcher's |
|
|
1830 | <code>data</code> member and is free for you to use.</p> |
|
|
1831 | <p>The prototype of the <code>function</code> must be <code>void (*)(ev::TYPE &w, int)</code>.</p> |
|
|
1832 | <p>See the method-<code>set</code> above for more details.</p> |
|
|
1833 | <p>Example:</p> |
|
|
1834 | <pre> static void io_cb (ev::io &w, int revents) { } |
|
|
1835 | iow.set <io_cb> (); |
|
|
1836 | |
|
|
1837 | </pre> |
1606 | </dd> |
1838 | </dd> |
1607 | <dt>w->set (struct ev_loop *)</dt> |
1839 | <dt>w->set (struct ev_loop *)</dt> |
1608 | <dd> |
1840 | <dd> |
1609 | <p>Associates a different <code>struct ev_loop</code> with this watcher. You can only |
1841 | <p>Associates a different <code>struct ev_loop</code> with this watcher. You can only |
1610 | do this when the watcher is inactive (and not pending either).</p> |
1842 | do this when the watcher is inactive (and not pending either).</p> |
1611 | </dd> |
1843 | </dd> |
1612 | <dt>w->set ([args])</dt> |
1844 | <dt>w->set ([args])</dt> |
1613 | <dd> |
1845 | <dd> |
1614 | <p>Basically the same as <code>ev_TYPE_set</code>, with the same args. Must be |
1846 | <p>Basically the same as <code>ev_TYPE_set</code>, with the same args. Must be |
1615 | called at least once. Unlike the C counterpart, an active watcher gets |
1847 | called at least once. Unlike the C counterpart, an active watcher gets |
1616 | automatically stopped and restarted.</p> |
1848 | automatically stopped and restarted when reconfiguring it with this |
|
|
1849 | method.</p> |
1617 | </dd> |
1850 | </dd> |
1618 | <dt>w->start ()</dt> |
1851 | <dt>w->start ()</dt> |
1619 | <dd> |
1852 | <dd> |
1620 | <p>Starts the watcher. Note that there is no <code>loop</code> argument as the |
1853 | <p>Starts the watcher. Note that there is no <code>loop</code> argument, as the |
1621 | constructor already takes the loop.</p> |
1854 | constructor already stores the event loop.</p> |
1622 | </dd> |
1855 | </dd> |
1623 | <dt>w->stop ()</dt> |
1856 | <dt>w->stop ()</dt> |
1624 | <dd> |
1857 | <dd> |
1625 | <p>Stops the watcher if it is active. Again, no <code>loop</code> argument.</p> |
1858 | <p>Stops the watcher if it is active. Again, no <code>loop</code> argument.</p> |
1626 | </dd> |
1859 | </dd> |
… | |
… | |
1630 | <code>ev_TYPE_again</code> function.</p> |
1863 | <code>ev_TYPE_again</code> function.</p> |
1631 | </dd> |
1864 | </dd> |
1632 | <dt>w->sweep () <code>ev::embed</code> only</dt> |
1865 | <dt>w->sweep () <code>ev::embed</code> only</dt> |
1633 | <dd> |
1866 | <dd> |
1634 | <p>Invokes <code>ev_embed_sweep</code>.</p> |
1867 | <p>Invokes <code>ev_embed_sweep</code>.</p> |
|
|
1868 | </dd> |
|
|
1869 | <dt>w->update () <code>ev::stat</code> only</dt> |
|
|
1870 | <dd> |
|
|
1871 | <p>Invokes <code>ev_stat_stat</code>.</p> |
1635 | </dd> |
1872 | </dd> |
1636 | </dl> |
1873 | </dl> |
1637 | </p> |
1874 | </p> |
1638 | </dd> |
1875 | </dd> |
1639 | </dl> |
1876 | </dl> |
… | |
… | |
1646 | |
1883 | |
1647 | myclass (); |
1884 | myclass (); |
1648 | } |
1885 | } |
1649 | |
1886 | |
1650 | myclass::myclass (int fd) |
1887 | myclass::myclass (int fd) |
1651 | : io (this, &myclass::io_cb), |
|
|
1652 | idle (this, &myclass::idle_cb) |
|
|
1653 | { |
1888 | { |
|
|
1889 | io .set <myclass, &myclass::io_cb > (this); |
|
|
1890 | idle.set <myclass, &myclass::idle_cb> (this); |
|
|
1891 | |
1654 | io.start (fd, ev::READ); |
1892 | io.start (fd, ev::READ); |
1655 | } |
1893 | } |
1656 | |
1894 | |
1657 | </pre> |
|
|
1658 | |
1895 | |
|
|
1896 | |
|
|
1897 | |
|
|
1898 | </pre> |
|
|
1899 | |
1659 | </div> |
1900 | </div> |
1660 | <h1 id="EMBEDDING">EMBEDDING</h1><p><a href="#TOP" class="toplink">Top</a></p> |
1901 | <h1 id="MACRO_MAGIC">MACRO MAGIC</h1> |
|
|
1902 | <div id="MACRO_MAGIC_CONTENT"> |
|
|
1903 | <p>Libev can be compiled with a variety of options, the most fundemantal is |
|
|
1904 | <code>EV_MULTIPLICITY</code>. This option determines whether (most) functions and |
|
|
1905 | callbacks have an initial <code>struct ev_loop *</code> argument.</p> |
|
|
1906 | <p>To make it easier to write programs that cope with either variant, the |
|
|
1907 | following macros are defined:</p> |
|
|
1908 | <dl> |
|
|
1909 | <dt><code>EV_A</code>, <code>EV_A_</code></dt> |
|
|
1910 | <dd> |
|
|
1911 | <p>This provides the loop <i>argument</i> for functions, if one is required ("ev |
|
|
1912 | loop argument"). The <code>EV_A</code> form is used when this is the sole argument, |
|
|
1913 | <code>EV_A_</code> is used when other arguments are following. Example:</p> |
|
|
1914 | <pre> ev_unref (EV_A); |
|
|
1915 | ev_timer_add (EV_A_ watcher); |
|
|
1916 | ev_loop (EV_A_ 0); |
|
|
1917 | |
|
|
1918 | </pre> |
|
|
1919 | <p>It assumes the variable <code>loop</code> of type <code>struct ev_loop *</code> is in scope, |
|
|
1920 | which is often provided by the following macro.</p> |
|
|
1921 | </dd> |
|
|
1922 | <dt><code>EV_P</code>, <code>EV_P_</code></dt> |
|
|
1923 | <dd> |
|
|
1924 | <p>This provides the loop <i>parameter</i> for functions, if one is required ("ev |
|
|
1925 | loop parameter"). The <code>EV_P</code> form is used when this is the sole parameter, |
|
|
1926 | <code>EV_P_</code> is used when other parameters are following. Example:</p> |
|
|
1927 | <pre> // this is how ev_unref is being declared |
|
|
1928 | static void ev_unref (EV_P); |
|
|
1929 | |
|
|
1930 | // this is how you can declare your typical callback |
|
|
1931 | static void cb (EV_P_ ev_timer *w, int revents) |
|
|
1932 | |
|
|
1933 | </pre> |
|
|
1934 | <p>It declares a parameter <code>loop</code> of type <code>struct ev_loop *</code>, quite |
|
|
1935 | suitable for use with <code>EV_A</code>.</p> |
|
|
1936 | </dd> |
|
|
1937 | <dt><code>EV_DEFAULT</code>, <code>EV_DEFAULT_</code></dt> |
|
|
1938 | <dd> |
|
|
1939 | <p>Similar to the other two macros, this gives you the value of the default |
|
|
1940 | loop, if multiple loops are supported ("ev loop default").</p> |
|
|
1941 | </dd> |
|
|
1942 | </dl> |
|
|
1943 | <p>Example: Declare and initialise a check watcher, utilising the above |
|
|
1944 | macros so it will work regardless of whether multiple loops are supported |
|
|
1945 | or not.</p> |
|
|
1946 | <pre> static void |
|
|
1947 | check_cb (EV_P_ ev_timer *w, int revents) |
|
|
1948 | { |
|
|
1949 | ev_check_stop (EV_A_ w); |
|
|
1950 | } |
|
|
1951 | |
|
|
1952 | ev_check check; |
|
|
1953 | ev_check_init (&check, check_cb); |
|
|
1954 | ev_check_start (EV_DEFAULT_ &check); |
|
|
1955 | ev_loop (EV_DEFAULT_ 0); |
|
|
1956 | |
|
|
1957 | </pre> |
|
|
1958 | |
|
|
1959 | </div> |
|
|
1960 | <h1 id="EMBEDDING">EMBEDDING</h1> |
1661 | <div id="EMBEDDING_CONTENT"> |
1961 | <div id="EMBEDDING_CONTENT"> |
1662 | <p>Libev can (and often is) directly embedded into host |
1962 | <p>Libev can (and often is) directly embedded into host |
1663 | applications. Examples of applications that embed it include the Deliantra |
1963 | applications. Examples of applications that embed it include the Deliantra |
1664 | Game Server, the EV perl module, the GNU Virtual Private Ethernet (gvpe) |
1964 | Game Server, the EV perl module, the GNU Virtual Private Ethernet (gvpe) |
1665 | and rxvt-unicode.</p> |
1965 | and rxvt-unicode.</p> |
… | |
… | |
1702 | ev_vars.h |
2002 | ev_vars.h |
1703 | ev_wrap.h |
2003 | ev_wrap.h |
1704 | |
2004 | |
1705 | ev_win32.c required on win32 platforms only |
2005 | ev_win32.c required on win32 platforms only |
1706 | |
2006 | |
1707 | ev_select.c only when select backend is enabled (which is by default) |
2007 | ev_select.c only when select backend is enabled (which is enabled by default) |
1708 | ev_poll.c only when poll backend is enabled (disabled by default) |
2008 | ev_poll.c only when poll backend is enabled (disabled by default) |
1709 | ev_epoll.c only when the epoll backend is enabled (disabled by default) |
2009 | ev_epoll.c only when the epoll backend is enabled (disabled by default) |
1710 | ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
2010 | ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
1711 | ev_port.c only when the solaris port backend is enabled (disabled by default) |
2011 | ev_port.c only when the solaris port backend is enabled (disabled by default) |
1712 | |
2012 | |
… | |
… | |
1839 | </dd> |
2139 | </dd> |
1840 | <dt>EV_USE_DEVPOLL</dt> |
2140 | <dt>EV_USE_DEVPOLL</dt> |
1841 | <dd> |
2141 | <dd> |
1842 | <p>reserved for future expansion, works like the USE symbols above.</p> |
2142 | <p>reserved for future expansion, works like the USE symbols above.</p> |
1843 | </dd> |
2143 | </dd> |
|
|
2144 | <dt>EV_USE_INOTIFY</dt> |
|
|
2145 | <dd> |
|
|
2146 | <p>If defined to be <code>1</code>, libev will compile in support for the Linux inotify |
|
|
2147 | interface to speed up <code>ev_stat</code> watchers. Its actual availability will |
|
|
2148 | be detected at runtime.</p> |
|
|
2149 | </dd> |
1844 | <dt>EV_H</dt> |
2150 | <dt>EV_H</dt> |
1845 | <dd> |
2151 | <dd> |
1846 | <p>The name of the <cite>ev.h</cite> header file used to include it. The default if |
2152 | <p>The name of the <cite>ev.h</cite> header file used to include it. The default if |
1847 | undefined is <code><ev.h></code> in <cite>event.h</cite> and <code>"ev.h"</code> in <cite>ev.c</cite>. This |
2153 | undefined is <code><ev.h></code> in <cite>event.h</cite> and <code>"ev.h"</code> in <cite>ev.c</cite>. This |
1848 | can be used to virtually rename the <cite>ev.h</cite> header file in case of conflicts.</p> |
2154 | can be used to virtually rename the <cite>ev.h</cite> header file in case of conflicts.</p> |
… | |
… | |
1871 | will have the <code>struct ev_loop *</code> as first argument, and you can create |
2177 | will have the <code>struct ev_loop *</code> as first argument, and you can create |
1872 | additional independent event loops. Otherwise there will be no support |
2178 | additional independent event loops. Otherwise there will be no support |
1873 | for multiple event loops and there is no first event loop pointer |
2179 | for multiple event loops and there is no first event loop pointer |
1874 | argument. Instead, all functions act on the single default loop.</p> |
2180 | argument. Instead, all functions act on the single default loop.</p> |
1875 | </dd> |
2181 | </dd> |
|
|
2182 | <dt>EV_MINPRI</dt> |
|
|
2183 | <dt>EV_MAXPRI</dt> |
|
|
2184 | <dd> |
|
|
2185 | <p>The range of allowed priorities. <code>EV_MINPRI</code> must be smaller or equal to |
|
|
2186 | <code>EV_MAXPRI</code>, but otherwise there are no non-obvious limitations. You can |
|
|
2187 | provide for more priorities by overriding those symbols (usually defined |
|
|
2188 | to be <code>-2</code> and <code>2</code>, respectively).</p> |
|
|
2189 | <p>When doing priority-based operations, libev usually has to linearly search |
|
|
2190 | all the priorities, so having many of them (hundreds) uses a lot of space |
|
|
2191 | and time, so using the defaults of five priorities (-2 .. +2) is usually |
|
|
2192 | fine.</p> |
|
|
2193 | <p>If your embedding app does not need any priorities, defining these both to |
|
|
2194 | <code>0</code> will save some memory and cpu.</p> |
|
|
2195 | </dd> |
1876 | <dt>EV_PERIODIC_ENABLE</dt> |
2196 | <dt>EV_PERIODIC_ENABLE</dt> |
1877 | <dd> |
2197 | <dd> |
1878 | <p>If undefined or defined to be <code>1</code>, then periodic timers are supported. If |
2198 | <p>If undefined or defined to be <code>1</code>, then periodic timers are supported. If |
1879 | defined to be <code>0</code>, then they are not. Disabling them saves a few kB of |
2199 | defined to be <code>0</code>, then they are not. Disabling them saves a few kB of |
1880 | code.</p> |
2200 | code.</p> |
1881 | </dd> |
2201 | </dd> |
|
|
2202 | <dt>EV_IDLE_ENABLE</dt> |
|
|
2203 | <dd> |
|
|
2204 | <p>If undefined or defined to be <code>1</code>, then idle watchers are supported. If |
|
|
2205 | defined to be <code>0</code>, then they are not. Disabling them saves a few kB of |
|
|
2206 | code.</p> |
|
|
2207 | </dd> |
1882 | <dt>EV_EMBED_ENABLE</dt> |
2208 | <dt>EV_EMBED_ENABLE</dt> |
1883 | <dd> |
2209 | <dd> |
1884 | <p>If undefined or defined to be <code>1</code>, then embed watchers are supported. If |
2210 | <p>If undefined or defined to be <code>1</code>, then embed watchers are supported. If |
1885 | defined to be <code>0</code>, then they are not.</p> |
2211 | defined to be <code>0</code>, then they are not.</p> |
1886 | </dd> |
2212 | </dd> |
1887 | <dt>EV_STAT_ENABLE</dt> |
2213 | <dt>EV_STAT_ENABLE</dt> |
1888 | <dd> |
2214 | <dd> |
1889 | <p>If undefined or defined to be <code>1</code>, then stat watchers are supported. If |
2215 | <p>If undefined or defined to be <code>1</code>, then stat watchers are supported. If |
|
|
2216 | defined to be <code>0</code>, then they are not.</p> |
|
|
2217 | </dd> |
|
|
2218 | <dt>EV_FORK_ENABLE</dt> |
|
|
2219 | <dd> |
|
|
2220 | <p>If undefined or defined to be <code>1</code>, then fork watchers are supported. If |
1890 | defined to be <code>0</code>, then they are not.</p> |
2221 | defined to be <code>0</code>, then they are not.</p> |
1891 | </dd> |
2222 | </dd> |
1892 | <dt>EV_MINIMAL</dt> |
2223 | <dt>EV_MINIMAL</dt> |
1893 | <dd> |
2224 | <dd> |
1894 | <p>If you need to shave off some kilobytes of code at the expense of some |
2225 | <p>If you need to shave off some kilobytes of code at the expense of some |
1895 | speed, define this symbol to <code>1</code>. Currently only used for gcc to override |
2226 | speed, define this symbol to <code>1</code>. Currently only used for gcc to override |
1896 | some inlining decisions, saves roughly 30% codesize of amd64.</p> |
2227 | some inlining decisions, saves roughly 30% codesize of amd64.</p> |
|
|
2228 | </dd> |
|
|
2229 | <dt>EV_PID_HASHSIZE</dt> |
|
|
2230 | <dd> |
|
|
2231 | <p><code>ev_child</code> watchers use a small hash table to distribute workload by |
|
|
2232 | pid. The default size is <code>16</code> (or <code>1</code> with <code>EV_MINIMAL</code>), usually more |
|
|
2233 | than enough. If you need to manage thousands of children you might want to |
|
|
2234 | increase this value (<i>must</i> be a power of two).</p> |
|
|
2235 | </dd> |
|
|
2236 | <dt>EV_INOTIFY_HASHSIZE</dt> |
|
|
2237 | <dd> |
|
|
2238 | <p><code>ev_staz</code> watchers use a small hash table to distribute workload by |
|
|
2239 | inotify watch id. The default size is <code>16</code> (or <code>1</code> with <code>EV_MINIMAL</code>), |
|
|
2240 | usually more than enough. If you need to manage thousands of <code>ev_stat</code> |
|
|
2241 | watchers you might want to increase this value (<i>must</i> be a power of |
|
|
2242 | two).</p> |
1897 | </dd> |
2243 | </dd> |
1898 | <dt>EV_COMMON</dt> |
2244 | <dt>EV_COMMON</dt> |
1899 | <dd> |
2245 | <dd> |
1900 | <p>By default, all watchers have a <code>void *data</code> member. By redefining |
2246 | <p>By default, all watchers have a <code>void *data</code> member. By redefining |
1901 | this macro to a something else you can include more and other types of |
2247 | this macro to a something else you can include more and other types of |
… | |
… | |
1928 | the <cite>libev/</cite> subdirectory and includes them in the <cite>EV/EVAPI.h</cite> (public |
2274 | the <cite>libev/</cite> subdirectory and includes them in the <cite>EV/EVAPI.h</cite> (public |
1929 | interface) and <cite>EV.xs</cite> (implementation) files. Only the <cite>EV.xs</cite> file |
2275 | interface) and <cite>EV.xs</cite> (implementation) files. Only the <cite>EV.xs</cite> file |
1930 | will be compiled. It is pretty complex because it provides its own header |
2276 | will be compiled. It is pretty complex because it provides its own header |
1931 | file.</p> |
2277 | file.</p> |
1932 | <p>The usage in rxvt-unicode is simpler. It has a <cite>ev_cpp.h</cite> header file |
2278 | <p>The usage in rxvt-unicode is simpler. It has a <cite>ev_cpp.h</cite> header file |
1933 | that everybody includes and which overrides some autoconf choices:</p> |
2279 | that everybody includes and which overrides some configure choices:</p> |
|
|
2280 | <pre> #define EV_MINIMAL 1 |
1934 | <pre> #define EV_USE_POLL 0 |
2281 | #define EV_USE_POLL 0 |
1935 | #define EV_MULTIPLICITY 0 |
2282 | #define EV_MULTIPLICITY 0 |
1936 | #define EV_PERIODICS 0 |
2283 | #define EV_PERIODIC_ENABLE 0 |
|
|
2284 | #define EV_STAT_ENABLE 0 |
|
|
2285 | #define EV_FORK_ENABLE 0 |
1937 | #define EV_CONFIG_H <config.h> |
2286 | #define EV_CONFIG_H <config.h> |
|
|
2287 | #define EV_MINPRI 0 |
|
|
2288 | #define EV_MAXPRI 0 |
1938 | |
2289 | |
1939 | #include "ev++.h" |
2290 | #include "ev++.h" |
1940 | |
2291 | |
1941 | </pre> |
2292 | </pre> |
1942 | <p>And a <cite>ev_cpp.C</cite> implementation file that contains libev proper and is compiled:</p> |
2293 | <p>And a <cite>ev_cpp.C</cite> implementation file that contains libev proper and is compiled:</p> |
… | |
… | |
1947 | |
2298 | |
1948 | |
2299 | |
1949 | </pre> |
2300 | </pre> |
1950 | |
2301 | |
1951 | </div> |
2302 | </div> |
1952 | <h1 id="COMPLEXITIES">COMPLEXITIES</h1><p><a href="#TOP" class="toplink">Top</a></p> |
2303 | <h1 id="COMPLEXITIES">COMPLEXITIES</h1> |
1953 | <div id="COMPLEXITIES_CONTENT"> |
2304 | <div id="COMPLEXITIES_CONTENT"> |
1954 | <p>In this section the complexities of (many of) the algorithms used inside |
2305 | <p>In this section the complexities of (many of) the algorithms used inside |
1955 | libev will be explained. For complexity discussions about backends see the |
2306 | libev will be explained. For complexity discussions about backends see the |
1956 | documentation for <code>ev_default_init</code>.</p> |
2307 | documentation for <code>ev_default_init</code>.</p> |
|
|
2308 | <p>All of the following are about amortised time: If an array needs to be |
|
|
2309 | extended, libev needs to realloc and move the whole array, but this |
|
|
2310 | happens asymptotically never with higher number of elements, so O(1) might |
|
|
2311 | mean it might do a lengthy realloc operation in rare cases, but on average |
|
|
2312 | it is much faster and asymptotically approaches constant time.</p> |
1957 | <p> |
2313 | <p> |
1958 | <dl> |
2314 | <dl> |
1959 | <dt>Starting and stopping timer/periodic watchers: O(log skipped_other_timers)</dt> |
2315 | <dt>Starting and stopping timer/periodic watchers: O(log skipped_other_timers)</dt> |
|
|
2316 | <dd> |
|
|
2317 | <p>This means that, when you have a watcher that triggers in one hour and |
|
|
2318 | there are 100 watchers that would trigger before that then inserting will |
|
|
2319 | have to skip those 100 watchers.</p> |
|
|
2320 | </dd> |
1960 | <dt>Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)</dt> |
2321 | <dt>Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)</dt> |
|
|
2322 | <dd> |
|
|
2323 | <p>That means that for changing a timer costs less than removing/adding them |
|
|
2324 | as only the relative motion in the event queue has to be paid for.</p> |
|
|
2325 | </dd> |
1961 | <dt>Starting io/check/prepare/idle/signal/child watchers: O(1)</dt> |
2326 | <dt>Starting io/check/prepare/idle/signal/child watchers: O(1)</dt> |
|
|
2327 | <dd> |
|
|
2328 | <p>These just add the watcher into an array or at the head of a list. |
1962 | <dt>Stopping check/prepare/idle watchers: O(1)</dt> |
2329 | =item Stopping check/prepare/idle watchers: O(1)</p> |
|
|
2330 | </dd> |
1963 | <dt>Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % 16))</dt> |
2331 | <dt>Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))</dt> |
|
|
2332 | <dd> |
|
|
2333 | <p>These watchers are stored in lists then need to be walked to find the |
|
|
2334 | correct watcher to remove. The lists are usually short (you don't usually |
|
|
2335 | have many watchers waiting for the same fd or signal).</p> |
|
|
2336 | </dd> |
1964 | <dt>Finding the next timer per loop iteration: O(1)</dt> |
2337 | <dt>Finding the next timer per loop iteration: O(1)</dt> |
1965 | <dt>Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)</dt> |
2338 | <dt>Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)</dt> |
|
|
2339 | <dd> |
|
|
2340 | <p>A change means an I/O watcher gets started or stopped, which requires |
|
|
2341 | libev to recalculate its status (and possibly tell the kernel).</p> |
|
|
2342 | </dd> |
1966 | <dt>Activating one watcher: O(1)</dt> |
2343 | <dt>Activating one watcher: O(1)</dt> |
|
|
2344 | <dt>Priority handling: O(number_of_priorities)</dt> |
|
|
2345 | <dd> |
|
|
2346 | <p>Priorities are implemented by allocating some space for each |
|
|
2347 | priority. When doing priority-based operations, libev usually has to |
|
|
2348 | linearly search all the priorities.</p> |
|
|
2349 | </dd> |
1967 | </dl> |
2350 | </dl> |
1968 | </p> |
2351 | </p> |
1969 | |
2352 | |
1970 | |
2353 | |
1971 | |
2354 | |
1972 | |
2355 | |
1973 | |
2356 | |
1974 | </div> |
2357 | </div> |
1975 | <h1 id="AUTHOR">AUTHOR</h1><p><a href="#TOP" class="toplink">Top</a></p> |
2358 | <h1 id="AUTHOR">AUTHOR</h1> |
1976 | <div id="AUTHOR_CONTENT"> |
2359 | <div id="AUTHOR_CONTENT"> |
1977 | <p>Marc Lehmann <libev@schmorp.de>.</p> |
2360 | <p>Marc Lehmann <libev@schmorp.de>.</p> |
1978 | |
2361 | |
1979 | </div> |
2362 | </div> |
1980 | </div></body> |
2363 | </div></body> |