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4 | <head> |
4 | <head> |
5 | <title>libev</title> |
5 | <title>libev</title> |
6 | <meta name="description" content="Pod documentation for libev" /> |
6 | <meta name="description" content="Pod documentation for libev" /> |
7 | <meta name="inputfile" content="<standard input>" /> |
7 | <meta name="inputfile" content="<standard input>" /> |
8 | <meta name="outputfile" content="<standard output>" /> |
8 | <meta name="outputfile" content="<standard output>" /> |
9 | <meta name="created" content="Tue Nov 27 20:23:27 2007" /> |
9 | <meta name="created" content="Thu Nov 29 21:05:58 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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59 | <li><a href="#AUTHOR">AUTHOR</a> |
60 | <li><a href="#AUTHOR">AUTHOR</a> |
60 | </li> |
61 | </li> |
61 | </ul><hr /> |
62 | </ul><hr /> |
62 | <!-- INDEX END --> |
63 | <!-- INDEX END --> |
63 | |
64 | |
64 | <h1 id="NAME">NAME</h1><p><a href="#TOP" class="toplink">Top</a></p> |
65 | <h1 id="NAME">NAME</h1> |
65 | <div id="NAME_CONTENT"> |
66 | <div id="NAME_CONTENT"> |
66 | <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> |
67 | |
68 | |
68 | </div> |
69 | </div> |
69 | <h1 id="SYNOPSIS">SYNOPSIS</h1><p><a href="#TOP" class="toplink">Top</a></p> |
70 | <h1 id="SYNOPSIS">SYNOPSIS</h1> |
70 | <div id="SYNOPSIS_CONTENT"> |
71 | <div id="SYNOPSIS_CONTENT"> |
71 | <pre> #include <ev.h> |
72 | <pre> #include <ev.h> |
72 | |
73 | |
73 | </pre> |
74 | </pre> |
74 | |
75 | |
75 | </div> |
76 | </div> |
76 | <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> |
77 | <div id="DESCRIPTION_CONTENT"> |
123 | <div id="DESCRIPTION_CONTENT"> |
78 | <p>Libev is an event loop: you register interest in certain events (such as a |
124 | <p>Libev is an event loop: you register interest in certain events (such as a |
79 | file descriptor being readable or a timeout occuring), and it will manage |
125 | file descriptor being readable or a timeout occuring), and it will manage |
80 | these event sources and provide your program with events.</p> |
126 | these event sources and provide your program with events.</p> |
81 | <p>To do this, it must take more or less complete control over your process |
127 | <p>To do this, it must take more or less complete control over your process |
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85 | watchers</i>, which are relatively small C structures you initialise with the |
131 | watchers</i>, which are relatively small C structures you initialise with the |
86 | details of the event, and then hand it over to libev by <i>starting</i> the |
132 | details of the event, and then hand it over to libev by <i>starting</i> the |
87 | watcher.</p> |
133 | watcher.</p> |
88 | |
134 | |
89 | </div> |
135 | </div> |
90 | <h1 id="FEATURES">FEATURES</h1><p><a href="#TOP" class="toplink">Top</a></p> |
136 | <h1 id="FEATURES">FEATURES</h1> |
91 | <div id="FEATURES_CONTENT"> |
137 | <div id="FEATURES_CONTENT"> |
92 | <p>Libev supports select, poll, the linux-specific epoll and the bsd-specific |
138 | <p>Libev supports <code>select</code>, <code>poll</code>, the Linux-specific <code>epoll</code>, the |
93 | kqueue mechanisms for file descriptor events, relative timers, absolute |
139 | BSD-specific <code>kqueue</code> and the Solaris-specific event port mechanisms |
94 | timers with customised rescheduling, signal events, process status change |
140 | for file descriptor events (<code>ev_io</code>), the Linux <code>inotify</code> interface |
95 | events (related to SIGCHLD), and event watchers dealing with the event |
141 | (for <code>ev_stat</code>), relative timers (<code>ev_timer</code>), absolute timers |
96 | loop mechanism itself (idle, prepare and check watchers). It also is quite |
142 | with customised rescheduling (<code>ev_periodic</code>), synchronous signals |
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143 | (<code>ev_signal</code>), process status change events (<code>ev_child</code>), and event |
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144 | watchers dealing with the event loop mechanism itself (<code>ev_idle</code>, |
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145 | <code>ev_embed</code>, <code>ev_prepare</code> and <code>ev_check</code> watchers) as well as |
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146 | file watchers (<code>ev_stat</code>) and even limited support for fork events |
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147 | (<code>ev_fork</code>).</p> |
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148 | <p>It also is quite fast (see this |
97 | fast (see this <a href="http://libev.schmorp.de/bench.html">benchmark</a> comparing |
149 | <a href="http://libev.schmorp.de/bench.html">benchmark</a> comparing it to libevent |
98 | it to libevent for example).</p> |
150 | for example).</p> |
99 | |
151 | |
100 | </div> |
152 | </div> |
101 | <h1 id="CONVENTIONS">CONVENTIONS</h1><p><a href="#TOP" class="toplink">Top</a></p> |
153 | <h1 id="CONVENTIONS">CONVENTIONS</h1> |
102 | <div id="CONVENTIONS_CONTENT"> |
154 | <div id="CONVENTIONS_CONTENT"> |
103 | <p>Libev is very configurable. In this manual the default configuration |
155 | <p>Libev is very configurable. In this manual the default configuration will |
104 | will be described, which supports multiple event loops. For more info |
156 | be described, which supports multiple event loops. For more info about |
105 | about various configuration options please have a look at the file |
157 | various configuration options please have a look at <strong>EMBED</strong> section in |
106 | <cite>README.embed</cite> in the libev distribution. If libev was configured without |
158 | this manual. If libev was configured without support for multiple event |
107 | support for multiple event loops, then all functions taking an initial |
159 | loops, then all functions taking an initial argument of name <code>loop</code> |
108 | argument of name <code>loop</code> (which is always of type <code>struct ev_loop *</code>) |
160 | (which is always of type <code>struct ev_loop *</code>) will not have this argument.</p> |
109 | will not have this argument.</p> |
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110 | |
161 | |
111 | </div> |
162 | </div> |
112 | <h1 id="TIME_REPRESENTATION">TIME REPRESENTATION</h1><p><a href="#TOP" class="toplink">Top</a></p> |
163 | <h1 id="TIME_REPRESENTATION">TIME REPRESENTATION</h1> |
113 | <div id="TIME_REPRESENTATION_CONTENT"> |
164 | <div id="TIME_REPRESENTATION_CONTENT"> |
114 | <p>Libev represents time as a single floating point number, representing the |
165 | <p>Libev represents time as a single floating point number, representing the |
115 | (fractional) number of seconds since the (POSIX) epoch (somewhere near |
166 | (fractional) number of seconds since the (POSIX) epoch (somewhere near |
116 | the beginning of 1970, details are complicated, don't ask). This type is |
167 | the beginning of 1970, details are complicated, don't ask). This type is |
117 | called <code>ev_tstamp</code>, which is what you should use too. It usually aliases |
168 | called <code>ev_tstamp</code>, which is what you should use too. It usually aliases |
118 | to the <code>double</code> type in C, and when you need to do any calculations on |
169 | to the <code>double</code> type in C, and when you need to do any calculations on |
119 | it, you should treat it as such.</p> |
170 | it, you should treat it as such.</p> |
120 | |
171 | |
121 | </div> |
172 | </div> |
122 | <h1 id="GLOBAL_FUNCTIONS">GLOBAL FUNCTIONS</h1><p><a href="#TOP" class="toplink">Top</a></p> |
173 | <h1 id="GLOBAL_FUNCTIONS">GLOBAL FUNCTIONS</h1> |
123 | <div id="GLOBAL_FUNCTIONS_CONTENT"> |
174 | <div id="GLOBAL_FUNCTIONS_CONTENT"> |
124 | <p>These functions can be called anytime, even before initialising the |
175 | <p>These functions can be called anytime, even before initialising the |
125 | library in any way.</p> |
176 | library in any way.</p> |
126 | <dl> |
177 | <dl> |
127 | <dt>ev_tstamp ev_time ()</dt> |
178 | <dt>ev_tstamp ev_time ()</dt> |
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140 | version of the library your program was compiled against.</p> |
191 | version of the library your program was compiled against.</p> |
141 | <p>Usually, it's a good idea to terminate if the major versions mismatch, |
192 | <p>Usually, it's a good idea to terminate if the major versions mismatch, |
142 | as this indicates an incompatible change. Minor versions are usually |
193 | as this indicates an incompatible change. Minor versions are usually |
143 | compatible to older versions, so a larger minor version alone is usually |
194 | compatible to older versions, so a larger minor version alone is usually |
144 | not a problem.</p> |
195 | not a problem.</p> |
145 | <p>Example: make sure we haven't accidentally been linked against the wrong |
196 | <p>Example: Make sure we haven't accidentally been linked against the wrong |
146 | version:</p> |
197 | version.</p> |
147 | <pre> assert (("libev version mismatch", |
198 | <pre> assert (("libev version mismatch", |
148 | ev_version_major () == EV_VERSION_MAJOR |
199 | ev_version_major () == EV_VERSION_MAJOR |
149 | && ev_version_minor () >= EV_VERSION_MINOR)); |
200 | && ev_version_minor () >= EV_VERSION_MINOR)); |
150 | |
201 | |
151 | </pre> |
202 | </pre> |
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181 | recommended ones.</p> |
232 | recommended ones.</p> |
182 | <p>See the description of <code>ev_embed</code> watchers for more info.</p> |
233 | <p>See the description of <code>ev_embed</code> watchers for more info.</p> |
183 | </dd> |
234 | </dd> |
184 | <dt>ev_set_allocator (void *(*cb)(void *ptr, long size))</dt> |
235 | <dt>ev_set_allocator (void *(*cb)(void *ptr, long size))</dt> |
185 | <dd> |
236 | <dd> |
186 | <p>Sets the allocation function to use (the prototype is similar to the |
237 | <p>Sets the allocation function to use (the prototype is similar - the |
187 | realloc C function, the semantics are identical). It is used to allocate |
238 | semantics is identical - to the realloc C function). It is used to |
188 | and free memory (no surprises here). If it returns zero when memory |
239 | allocate and free memory (no surprises here). If it returns zero when |
189 | needs to be allocated, the library might abort or take some potentially |
240 | memory needs to be allocated, the library might abort or take some |
190 | destructive action. The default is your system realloc function.</p> |
241 | potentially destructive action. The default is your system realloc |
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242 | function.</p> |
191 | <p>You could override this function in high-availability programs to, say, |
243 | <p>You could override this function in high-availability programs to, say, |
192 | free some memory if it cannot allocate memory, to use a special allocator, |
244 | free some memory if it cannot allocate memory, to use a special allocator, |
193 | or even to sleep a while and retry until some memory is available.</p> |
245 | or even to sleep a while and retry until some memory is available.</p> |
194 | <p>Example: replace the libev allocator with one that waits a bit and then |
246 | <p>Example: Replace the libev allocator with one that waits a bit and then |
195 | retries: better than mine).</p> |
247 | retries).</p> |
196 | <pre> static void * |
248 | <pre> static void * |
197 | persistent_realloc (void *ptr, long size) |
249 | persistent_realloc (void *ptr, size_t size) |
198 | { |
250 | { |
199 | for (;;) |
251 | for (;;) |
200 | { |
252 | { |
201 | void *newptr = realloc (ptr, size); |
253 | void *newptr = realloc (ptr, size); |
202 | |
254 | |
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219 | indicating the system call or subsystem causing the problem. If this |
271 | indicating the system call or subsystem causing the problem. If this |
220 | callback is set, then libev will expect it to remedy the sitution, no |
272 | callback is set, then libev will expect it to remedy the sitution, no |
221 | matter what, when it returns. That is, libev will generally retry the |
273 | matter what, when it returns. That is, libev will generally retry the |
222 | requested operation, or, if the condition doesn't go away, do bad stuff |
274 | requested operation, or, if the condition doesn't go away, do bad stuff |
223 | (such as abort).</p> |
275 | (such as abort).</p> |
224 | <p>Example: do the same thing as libev does internally:</p> |
276 | <p>Example: This is basically the same thing that libev does internally, too.</p> |
225 | <pre> static void |
277 | <pre> static void |
226 | fatal_error (const char *msg) |
278 | fatal_error (const char *msg) |
227 | { |
279 | { |
228 | perror (msg); |
280 | perror (msg); |
229 | abort (); |
281 | abort (); |
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235 | </pre> |
287 | </pre> |
236 | </dd> |
288 | </dd> |
237 | </dl> |
289 | </dl> |
238 | |
290 | |
239 | </div> |
291 | </div> |
240 | <h1 id="FUNCTIONS_CONTROLLING_THE_EVENT_LOOP">FUNCTIONS CONTROLLING THE EVENT LOOP</h1><p><a href="#TOP" class="toplink">Top</a></p> |
292 | <h1 id="FUNCTIONS_CONTROLLING_THE_EVENT_LOOP">FUNCTIONS CONTROLLING THE EVENT LOOP</h1> |
241 | <div id="FUNCTIONS_CONTROLLING_THE_EVENT_LOOP-2"> |
293 | <div id="FUNCTIONS_CONTROLLING_THE_EVENT_LOOP-2"> |
242 | <p>An event loop is described by a <code>struct ev_loop *</code>. The library knows two |
294 | <p>An event loop is described by a <code>struct ev_loop *</code>. The library knows two |
243 | types of such loops, the <i>default</i> loop, which supports signals and child |
295 | types of such loops, the <i>default</i> loop, which supports signals and child |
244 | events, and dynamically created loops which do not.</p> |
296 | events, and dynamically created loops which do not.</p> |
245 | <p>If you use threads, a common model is to run the default event loop |
297 | <p>If you use threads, a common model is to run the default event loop |
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273 | or setgid) then libev will <i>not</i> look at the environment variable |
325 | or setgid) then libev will <i>not</i> look at the environment variable |
274 | <code>LIBEV_FLAGS</code>. Otherwise (the default), this environment variable will |
326 | <code>LIBEV_FLAGS</code>. Otherwise (the default), this environment variable will |
275 | override the flags completely if it is found in the environment. This is |
327 | override the flags completely if it is found in the environment. This is |
276 | useful to try out specific backends to test their performance, or to work |
328 | useful to try out specific backends to test their performance, or to work |
277 | around bugs.</p> |
329 | around bugs.</p> |
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330 | </dd> |
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331 | <dt><code>EVFLAG_FORKCHECK</code></dt> |
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332 | <dd> |
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333 | <p>Instead of calling <code>ev_default_fork</code> or <code>ev_loop_fork</code> manually after |
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334 | a fork, you can also make libev check for a fork in each iteration by |
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335 | enabling this flag.</p> |
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336 | <p>This works by calling <code>getpid ()</code> on every iteration of the loop, |
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337 | and thus this might slow down your event loop if you do a lot of loop |
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338 | iterations and little real work, but is usually not noticable (on my |
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339 | Linux system for example, <code>getpid</code> is actually a simple 5-insn sequence |
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340 | without a syscall and thus <i>very</i> fast, but my Linux system also has |
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341 | <code>pthread_atfork</code> which is even faster).</p> |
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342 | <p>The big advantage of this flag is that you can forget about fork (and |
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343 | forget about forgetting to tell libev about forking) when you use this |
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344 | flag.</p> |
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345 | <p>This flag setting cannot be overriden or specified in the <code>LIBEV_FLAGS</code> |
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346 | environment variable.</p> |
278 | </dd> |
347 | </dd> |
279 | <dt><code>EVBACKEND_SELECT</code> (value 1, portable select backend)</dt> |
348 | <dt><code>EVBACKEND_SELECT</code> (value 1, portable select backend)</dt> |
280 | <dd> |
349 | <dd> |
281 | <p>This is your standard select(2) backend. Not <i>completely</i> standard, as |
350 | <p>This is your standard select(2) backend. Not <i>completely</i> standard, as |
282 | libev tries to roll its own fd_set with no limits on the number of fds, |
351 | libev tries to roll its own fd_set with no limits on the number of fds, |
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365 | <dd> |
434 | <dd> |
366 | <p>Similar to <code>ev_default_loop</code>, but always creates a new event loop that is |
435 | <p>Similar to <code>ev_default_loop</code>, but always creates a new event loop that is |
367 | always distinct from the default loop. Unlike the default loop, it cannot |
436 | always distinct from the default loop. Unlike the default loop, it cannot |
368 | handle signal and child watchers, and attempts to do so will be greeted by |
437 | handle signal and child watchers, and attempts to do so will be greeted by |
369 | undefined behaviour (or a failed assertion if assertions are enabled).</p> |
438 | undefined behaviour (or a failed assertion if assertions are enabled).</p> |
370 | <p>Example: try to create a event loop that uses epoll and nothing else.</p> |
439 | <p>Example: Try to create a event loop that uses epoll and nothing else.</p> |
371 | <pre> struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
440 | <pre> struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
372 | if (!epoller) |
441 | if (!epoller) |
373 | fatal ("no epoll found here, maybe it hides under your chair"); |
442 | fatal ("no epoll found here, maybe it hides under your chair"); |
374 | |
443 | |
375 | </pre> |
444 | </pre> |
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468 | be handled here by queueing them when their watcher gets executed. |
537 | be handled here by queueing them when their watcher gets executed. |
469 | - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
538 | - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
470 | were used, return, otherwise continue with step *. |
539 | were used, return, otherwise continue with step *. |
471 | |
540 | |
472 | </pre> |
541 | </pre> |
473 | <p>Example: queue some jobs and then loop until no events are outsanding |
542 | <p>Example: Queue some jobs and then loop until no events are outsanding |
474 | anymore.</p> |
543 | anymore.</p> |
475 | <pre> ... queue jobs here, make sure they register event watchers as long |
544 | <pre> ... queue jobs here, make sure they register event watchers as long |
476 | ... as they still have work to do (even an idle watcher will do..) |
545 | ... as they still have work to do (even an idle watcher will do..) |
477 | ev_loop (my_loop, 0); |
546 | ev_loop (my_loop, 0); |
478 | ... jobs done. yeah! |
547 | ... jobs done. yeah! |
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497 | example, libev itself uses this for its internal signal pipe: It is not |
566 | example, libev itself uses this for its internal signal pipe: It is not |
498 | visible to the libev user and should not keep <code>ev_loop</code> from exiting if |
567 | visible to the libev user and should not keep <code>ev_loop</code> from exiting if |
499 | no event watchers registered by it are active. It is also an excellent |
568 | no event watchers registered by it are active. It is also an excellent |
500 | way to do this for generic recurring timers or from within third-party |
569 | way to do this for generic recurring timers or from within third-party |
501 | libraries. Just remember to <i>unref after start</i> and <i>ref before stop</i>.</p> |
570 | libraries. Just remember to <i>unref after start</i> and <i>ref before stop</i>.</p> |
502 | <p>Example: create a signal watcher, but keep it from keeping <code>ev_loop</code> |
571 | <p>Example: Create a signal watcher, but keep it from keeping <code>ev_loop</code> |
503 | running when nothing else is active.</p> |
572 | running when nothing else is active.</p> |
504 | <pre> struct dv_signal exitsig; |
573 | <pre> struct ev_signal exitsig; |
505 | ev_signal_init (&exitsig, sig_cb, SIGINT); |
574 | ev_signal_init (&exitsig, sig_cb, SIGINT); |
506 | ev_signal_start (myloop, &exitsig); |
575 | ev_signal_start (loop, &exitsig); |
507 | evf_unref (myloop); |
576 | evf_unref (loop); |
508 | |
577 | |
509 | </pre> |
578 | </pre> |
510 | <p>Example: for some weird reason, unregister the above signal handler again.</p> |
579 | <p>Example: For some weird reason, unregister the above signal handler again.</p> |
511 | <pre> ev_ref (myloop); |
580 | <pre> ev_ref (loop); |
512 | ev_signal_stop (myloop, &exitsig); |
581 | ev_signal_stop (loop, &exitsig); |
513 | |
582 | |
514 | </pre> |
583 | </pre> |
515 | </dd> |
584 | </dd> |
516 | </dl> |
585 | </dl> |
517 | |
586 | |
518 | |
587 | |
519 | |
588 | |
520 | |
589 | |
521 | |
590 | |
522 | </div> |
591 | </div> |
523 | <h1 id="ANATOMY_OF_A_WATCHER">ANATOMY OF A WATCHER</h1><p><a href="#TOP" class="toplink">Top</a></p> |
592 | <h1 id="ANATOMY_OF_A_WATCHER">ANATOMY OF A WATCHER</h1> |
524 | <div id="ANATOMY_OF_A_WATCHER_CONTENT"> |
593 | <div id="ANATOMY_OF_A_WATCHER_CONTENT"> |
525 | <p>A watcher is a structure that you create and register to record your |
594 | <p>A watcher is a structure that you create and register to record your |
526 | interest in some event. For instance, if you want to wait for STDIN to |
595 | interest in some event. For instance, if you want to wait for STDIN to |
527 | become readable, you would create an <code>ev_io</code> watcher for that:</p> |
596 | become readable, you would create an <code>ev_io</code> watcher for that:</p> |
528 | <pre> static void my_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
597 | <pre> static void my_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
… | |
… | |
691 | events but its callback has not yet been invoked). As long as a watcher |
760 | events but its callback has not yet been invoked). As long as a watcher |
692 | is pending (but not active) you must not call an init function on it (but |
761 | is pending (but not active) you must not call an init function on it (but |
693 | <code>ev_TYPE_set</code> is safe) and you must make sure the watcher is available to |
762 | <code>ev_TYPE_set</code> is safe) and you must make sure the watcher is available to |
694 | libev (e.g. you cnanot <code>free ()</code> it).</p> |
763 | libev (e.g. you cnanot <code>free ()</code> it).</p> |
695 | </dd> |
764 | </dd> |
696 | <dt>callback = ev_cb (ev_TYPE *watcher)</dt> |
765 | <dt>callback ev_cb (ev_TYPE *watcher)</dt> |
697 | <dd> |
766 | <dd> |
698 | <p>Returns the callback currently set on the watcher.</p> |
767 | <p>Returns the callback currently set on the watcher.</p> |
699 | </dd> |
768 | </dd> |
700 | <dt>ev_cb_set (ev_TYPE *watcher, callback)</dt> |
769 | <dt>ev_cb_set (ev_TYPE *watcher, callback)</dt> |
701 | <dd> |
770 | <dd> |
… | |
… | |
733 | struct my_io *w = (struct my_io *)w_; |
802 | struct my_io *w = (struct my_io *)w_; |
734 | ... |
803 | ... |
735 | } |
804 | } |
736 | |
805 | |
737 | </pre> |
806 | </pre> |
738 | <p>More interesting and less C-conformant ways of catsing your callback type |
807 | <p>More interesting and less C-conformant ways of casting your callback type |
739 | have been omitted....</p> |
808 | instead have been omitted.</p> |
|
|
809 | <p>Another common scenario is having some data structure with multiple |
|
|
810 | watchers:</p> |
|
|
811 | <pre> struct my_biggy |
|
|
812 | { |
|
|
813 | int some_data; |
|
|
814 | ev_timer t1; |
|
|
815 | ev_timer t2; |
|
|
816 | } |
740 | |
817 | |
|
|
818 | </pre> |
|
|
819 | <p>In this case getting the pointer to <code>my_biggy</code> is a bit more complicated, |
|
|
820 | you need to use <code>offsetof</code>:</p> |
|
|
821 | <pre> #include <stddef.h> |
741 | |
822 | |
|
|
823 | static void |
|
|
824 | t1_cb (EV_P_ struct ev_timer *w, int revents) |
|
|
825 | { |
|
|
826 | struct my_biggy big = (struct my_biggy * |
|
|
827 | (((char *)w) - offsetof (struct my_biggy, t1)); |
|
|
828 | } |
742 | |
829 | |
|
|
830 | static void |
|
|
831 | t2_cb (EV_P_ struct ev_timer *w, int revents) |
|
|
832 | { |
|
|
833 | struct my_biggy big = (struct my_biggy * |
|
|
834 | (((char *)w) - offsetof (struct my_biggy, t2)); |
|
|
835 | } |
743 | |
836 | |
744 | |
837 | |
|
|
838 | |
|
|
839 | |
|
|
840 | </pre> |
|
|
841 | |
745 | </div> |
842 | </div> |
746 | <h1 id="WATCHER_TYPES">WATCHER TYPES</h1><p><a href="#TOP" class="toplink">Top</a></p> |
843 | <h1 id="WATCHER_TYPES">WATCHER TYPES</h1> |
747 | <div id="WATCHER_TYPES_CONTENT"> |
844 | <div id="WATCHER_TYPES_CONTENT"> |
748 | <p>This section describes each watcher in detail, but will not repeat |
845 | <p>This section describes each watcher in detail, but will not repeat |
749 | information given in the last section. Any initialisation/set macros, |
846 | information given in the last section. Any initialisation/set macros, |
750 | functions and members specific to the watcher type are explained.</p> |
847 | functions and members specific to the watcher type are explained.</p> |
751 | <p>Members are additionally marked with either <i>[read-only]</i>, meaning that, |
848 | <p>Members are additionally marked with either <i>[read-only]</i>, meaning that, |
… | |
… | |
811 | <dt>int events [read-only]</dt> |
908 | <dt>int events [read-only]</dt> |
812 | <dd> |
909 | <dd> |
813 | <p>The events being watched.</p> |
910 | <p>The events being watched.</p> |
814 | </dd> |
911 | </dd> |
815 | </dl> |
912 | </dl> |
816 | <p>Example: call <code>stdin_readable_cb</code> when STDIN_FILENO has become, well |
913 | <p>Example: Call <code>stdin_readable_cb</code> when STDIN_FILENO has become, well |
817 | readable, but only once. Since it is likely line-buffered, you could |
914 | readable, but only once. Since it is likely line-buffered, you could |
818 | attempt to read a whole line in the callback:</p> |
915 | attempt to read a whole line in the callback.</p> |
819 | <pre> static void |
916 | <pre> static void |
820 | stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
917 | stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
821 | { |
918 | { |
822 | ev_io_stop (loop, w); |
919 | ev_io_stop (loop, w); |
823 | .. read from stdin here (or from w->fd) and haqndle any I/O errors |
920 | .. read from stdin here (or from w->fd) and haqndle any I/O errors |
… | |
… | |
872 | </dd> |
969 | </dd> |
873 | <dt>ev_timer_again (loop)</dt> |
970 | <dt>ev_timer_again (loop)</dt> |
874 | <dd> |
971 | <dd> |
875 | <p>This will act as if the timer timed out and restart it again if it is |
972 | <p>This will act as if the timer timed out and restart it again if it is |
876 | repeating. The exact semantics are:</p> |
973 | repeating. The exact semantics are:</p> |
|
|
974 | <p>If the timer is pending, its pending status is cleared.</p> |
877 | <p>If the timer is started but nonrepeating, stop it.</p> |
975 | <p>If the timer is started but nonrepeating, stop it (as if it timed out).</p> |
878 | <p>If the timer is repeating, either start it if necessary (with the repeat |
976 | <p>If the timer is repeating, either start it if necessary (with the |
879 | value), or reset the running timer to the repeat value.</p> |
977 | <code>repeat</code> value), or reset the running timer to the <code>repeat</code> value.</p> |
880 | <p>This sounds a bit complicated, but here is a useful and typical |
978 | <p>This sounds a bit complicated, but here is a useful and typical |
881 | example: Imagine you have a tcp connection and you want a so-called |
979 | example: Imagine you have a tcp connection and you want a so-called idle |
882 | idle timeout, that is, you want to be called when there have been, |
980 | timeout, that is, you want to be called when there have been, say, 60 |
883 | say, 60 seconds of inactivity on the socket. The easiest way to do |
981 | seconds of inactivity on the socket. The easiest way to do this is to |
884 | this is to configure an <code>ev_timer</code> with <code>after</code>=<code>repeat</code>=<code>60</code> and calling |
982 | configure an <code>ev_timer</code> with a <code>repeat</code> value of <code>60</code> and then call |
885 | <code>ev_timer_again</code> each time you successfully read or write some data. If |
983 | <code>ev_timer_again</code> each time you successfully read or write some data. If |
886 | you go into an idle state where you do not expect data to travel on the |
984 | you go into an idle state where you do not expect data to travel on the |
887 | socket, you can stop the timer, and again will automatically restart it if |
985 | socket, you can <code>ev_timer_stop</code> the timer, and <code>ev_timer_again</code> will |
888 | need be.</p> |
986 | automatically restart it if need be.</p> |
889 | <p>You can also ignore the <code>after</code> value and <code>ev_timer_start</code> altogether |
987 | <p>That means you can ignore the <code>after</code> value and <code>ev_timer_start</code> |
890 | and only ever use the <code>repeat</code> value:</p> |
988 | altogether and only ever use the <code>repeat</code> value and <code>ev_timer_again</code>:</p> |
891 | <pre> ev_timer_init (timer, callback, 0., 5.); |
989 | <pre> ev_timer_init (timer, callback, 0., 5.); |
892 | ev_timer_again (loop, timer); |
990 | ev_timer_again (loop, timer); |
893 | ... |
991 | ... |
894 | timer->again = 17.; |
992 | timer->again = 17.; |
895 | ev_timer_again (loop, timer); |
993 | ev_timer_again (loop, timer); |
896 | ... |
994 | ... |
897 | timer->again = 10.; |
995 | timer->again = 10.; |
898 | ev_timer_again (loop, timer); |
996 | ev_timer_again (loop, timer); |
899 | |
997 | |
900 | </pre> |
998 | </pre> |
901 | <p>This is more efficient then stopping/starting the timer eahc time you want |
999 | <p>This is more slightly efficient then stopping/starting the timer each time |
902 | to modify its timeout value.</p> |
1000 | you want to modify its timeout value.</p> |
903 | </dd> |
1001 | </dd> |
904 | <dt>ev_tstamp repeat [read-write]</dt> |
1002 | <dt>ev_tstamp repeat [read-write]</dt> |
905 | <dd> |
1003 | <dd> |
906 | <p>The current <code>repeat</code> value. Will be used each time the watcher times out |
1004 | <p>The current <code>repeat</code> value. Will be used each time the watcher times out |
907 | or <code>ev_timer_again</code> is called and determines the next timeout (if any), |
1005 | or <code>ev_timer_again</code> is called and determines the next timeout (if any), |
908 | which is also when any modifications are taken into account.</p> |
1006 | which is also when any modifications are taken into account.</p> |
909 | </dd> |
1007 | </dd> |
910 | </dl> |
1008 | </dl> |
911 | <p>Example: create a timer that fires after 60 seconds.</p> |
1009 | <p>Example: Create a timer that fires after 60 seconds.</p> |
912 | <pre> static void |
1010 | <pre> static void |
913 | one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1011 | one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
914 | { |
1012 | { |
915 | .. one minute over, w is actually stopped right here |
1013 | .. one minute over, w is actually stopped right here |
916 | } |
1014 | } |
… | |
… | |
918 | struct ev_timer mytimer; |
1016 | struct ev_timer mytimer; |
919 | ev_timer_init (&mytimer, one_minute_cb, 60., 0.); |
1017 | ev_timer_init (&mytimer, one_minute_cb, 60., 0.); |
920 | ev_timer_start (loop, &mytimer); |
1018 | ev_timer_start (loop, &mytimer); |
921 | |
1019 | |
922 | </pre> |
1020 | </pre> |
923 | <p>Example: create a timeout timer that times out after 10 seconds of |
1021 | <p>Example: Create a timeout timer that times out after 10 seconds of |
924 | inactivity.</p> |
1022 | inactivity.</p> |
925 | <pre> static void |
1023 | <pre> static void |
926 | timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1024 | timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
927 | { |
1025 | { |
928 | .. ten seconds without any activity |
1026 | .. ten seconds without any activity |
… | |
… | |
1044 | <p>The current reschedule callback, or <code>0</code>, if this functionality is |
1142 | <p>The current reschedule callback, or <code>0</code>, if this functionality is |
1045 | switched off. Can be changed any time, but changes only take effect when |
1143 | switched off. Can be changed any time, but changes only take effect when |
1046 | the periodic timer fires or <code>ev_periodic_again</code> is being called.</p> |
1144 | the periodic timer fires or <code>ev_periodic_again</code> is being called.</p> |
1047 | </dd> |
1145 | </dd> |
1048 | </dl> |
1146 | </dl> |
1049 | <p>Example: call a callback every hour, or, more precisely, whenever the |
1147 | <p>Example: Call a callback every hour, or, more precisely, whenever the |
1050 | system clock is divisible by 3600. The callback invocation times have |
1148 | system clock is divisible by 3600. The callback invocation times have |
1051 | potentially a lot of jittering, but good long-term stability.</p> |
1149 | potentially a lot of jittering, but good long-term stability.</p> |
1052 | <pre> static void |
1150 | <pre> static void |
1053 | clock_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
1151 | clock_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
1054 | { |
1152 | { |
… | |
… | |
1058 | struct ev_periodic hourly_tick; |
1156 | struct ev_periodic hourly_tick; |
1059 | ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); |
1157 | ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); |
1060 | ev_periodic_start (loop, &hourly_tick); |
1158 | ev_periodic_start (loop, &hourly_tick); |
1061 | |
1159 | |
1062 | </pre> |
1160 | </pre> |
1063 | <p>Example: the same as above, but use a reschedule callback to do it:</p> |
1161 | <p>Example: The same as above, but use a reschedule callback to do it:</p> |
1064 | <pre> #include <math.h> |
1162 | <pre> #include <math.h> |
1065 | |
1163 | |
1066 | static ev_tstamp |
1164 | static ev_tstamp |
1067 | my_scheduler_cb (struct ev_periodic *w, ev_tstamp now) |
1165 | my_scheduler_cb (struct ev_periodic *w, ev_tstamp now) |
1068 | { |
1166 | { |
… | |
… | |
1070 | } |
1168 | } |
1071 | |
1169 | |
1072 | ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); |
1170 | ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); |
1073 | |
1171 | |
1074 | </pre> |
1172 | </pre> |
1075 | <p>Example: call a callback every hour, starting now:</p> |
1173 | <p>Example: Call a callback every hour, starting now:</p> |
1076 | <pre> struct ev_periodic hourly_tick; |
1174 | <pre> struct ev_periodic hourly_tick; |
1077 | ev_periodic_init (&hourly_tick, clock_cb, |
1175 | ev_periodic_init (&hourly_tick, clock_cb, |
1078 | fmod (ev_now (loop), 3600.), 3600., 0); |
1176 | fmod (ev_now (loop), 3600.), 3600., 0); |
1079 | ev_periodic_start (loop, &hourly_tick); |
1177 | ev_periodic_start (loop, &hourly_tick); |
1080 | |
1178 | |
… | |
… | |
1141 | <dd> |
1239 | <dd> |
1142 | <p>The process exit/trace status caused by <code>rpid</code> (see your systems |
1240 | <p>The process exit/trace status caused by <code>rpid</code> (see your systems |
1143 | <code>waitpid</code> and <code>sys/wait.h</code> documentation for details).</p> |
1241 | <code>waitpid</code> and <code>sys/wait.h</code> documentation for details).</p> |
1144 | </dd> |
1242 | </dd> |
1145 | </dl> |
1243 | </dl> |
1146 | <p>Example: try to exit cleanly on SIGINT and SIGTERM.</p> |
1244 | <p>Example: Try to exit cleanly on SIGINT and SIGTERM.</p> |
1147 | <pre> static void |
1245 | <pre> static void |
1148 | sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
1246 | sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
1149 | { |
1247 | { |
1150 | ev_unloop (loop, EVUNLOOP_ALL); |
1248 | ev_unloop (loop, EVUNLOOP_ALL); |
1151 | } |
1249 | } |
… | |
… | |
1168 | <p>The path does not need to exist: changing from "path exists" to "path does |
1266 | <p>The path does not need to exist: changing from "path exists" to "path does |
1169 | not exist" is a status change like any other. The condition "path does |
1267 | not exist" is a status change like any other. The condition "path does |
1170 | not exist" is signified by the <code>st_nlink</code> field being zero (which is |
1268 | not exist" is signified by the <code>st_nlink</code> field being zero (which is |
1171 | otherwise always forced to be at least one) and all the other fields of |
1269 | otherwise always forced to be at least one) and all the other fields of |
1172 | the stat buffer having unspecified contents.</p> |
1270 | the stat buffer having unspecified contents.</p> |
|
|
1271 | <p>The path <i>should</i> be absolute and <i>must not</i> end in a slash. If it is |
|
|
1272 | relative and your working directory changes, the behaviour is undefined.</p> |
1173 | <p>Since there is no standard to do this, the portable implementation simply |
1273 | <p>Since there is no standard to do this, the portable implementation simply |
1174 | calls <code>stat (2)</code> regulalry on the path to see if it changed somehow. You |
1274 | calls <code>stat (2)</code> regularly on the path to see if it changed somehow. You |
1175 | can specify a recommended polling interval for this case. If you specify |
1275 | can specify a recommended polling interval for this case. If you specify |
1176 | a polling interval of <code>0</code> (highly recommended!) then a <i>suitable, |
1276 | a polling interval of <code>0</code> (highly recommended!) then a <i>suitable, |
1177 | unspecified default</i> value will be used (which you can expect to be around |
1277 | unspecified default</i> value will be used (which you can expect to be around |
1178 | five seconds, although this might change dynamically). Libev will also |
1278 | five seconds, although this might change dynamically). Libev will also |
1179 | impose a minimum interval which is currently around <code>0.1</code>, but thats |
1279 | impose a minimum interval which is currently around <code>0.1</code>, but thats |
1180 | usually overkill.</p> |
1280 | usually overkill.</p> |
1181 | <p>This watcher type is not meant for massive numbers of stat watchers, |
1281 | <p>This watcher type is not meant for massive numbers of stat watchers, |
1182 | as even with OS-supported change notifications, this can be |
1282 | as even with OS-supported change notifications, this can be |
1183 | resource-intensive.</p> |
1283 | resource-intensive.</p> |
1184 | <p>At the time of this writing, no specific OS backends are implemented, but |
1284 | <p>At the time of this writing, only the Linux inotify interface is |
1185 | if demand increases, at least a kqueue and inotify backend will be added.</p> |
1285 | implemented (implementing kqueue support is left as an exercise for the |
|
|
1286 | reader). Inotify will be used to give hints only and should not change the |
|
|
1287 | semantics of <code>ev_stat</code> watchers, which means that libev sometimes needs |
|
|
1288 | to fall back to regular polling again even with inotify, but changes are |
|
|
1289 | usually detected immediately, and if the file exists there will be no |
|
|
1290 | polling.</p> |
1186 | <dl> |
1291 | <dl> |
1187 | <dt>ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)</dt> |
1292 | <dt>ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)</dt> |
1188 | <dt>ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)</dt> |
1293 | <dt>ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)</dt> |
1189 | <dd> |
1294 | <dd> |
1190 | <p>Configures the watcher to wait for status changes of the given |
1295 | <p>Configures the watcher to wait for status changes of the given |
… | |
… | |
1274 | <p>Initialises and configures the idle watcher - it has no parameters of any |
1379 | <p>Initialises and configures the idle watcher - it has no parameters of any |
1275 | kind. There is a <code>ev_idle_set</code> macro, but using it is utterly pointless, |
1380 | kind. There is a <code>ev_idle_set</code> macro, but using it is utterly pointless, |
1276 | believe me.</p> |
1381 | believe me.</p> |
1277 | </dd> |
1382 | </dd> |
1278 | </dl> |
1383 | </dl> |
1279 | <p>Example: dynamically allocate an <code>ev_idle</code>, start it, and in the |
1384 | <p>Example: Dynamically allocate an <code>ev_idle</code> watcher, start it, and in the |
1280 | callback, free it. Alos, use no error checking, as usual.</p> |
1385 | callback, free it. Also, use no error checking, as usual.</p> |
1281 | <pre> static void |
1386 | <pre> static void |
1282 | idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
1387 | idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
1283 | { |
1388 | { |
1284 | free (w); |
1389 | free (w); |
1285 | // now do something you wanted to do when the program has |
1390 | // now do something you wanted to do when the program has |
… | |
… | |
1510 | |
1615 | |
1511 | |
1616 | |
1512 | |
1617 | |
1513 | |
1618 | |
1514 | </div> |
1619 | </div> |
1515 | <h1 id="OTHER_FUNCTIONS">OTHER FUNCTIONS</h1><p><a href="#TOP" class="toplink">Top</a></p> |
1620 | <h1 id="OTHER_FUNCTIONS">OTHER FUNCTIONS</h1> |
1516 | <div id="OTHER_FUNCTIONS_CONTENT"> |
1621 | <div id="OTHER_FUNCTIONS_CONTENT"> |
1517 | <p>There are some other functions of possible interest. Described. Here. Now.</p> |
1622 | <p>There are some other functions of possible interest. Described. Here. Now.</p> |
1518 | <dl> |
1623 | <dl> |
1519 | <dt>ev_once (loop, int fd, int events, ev_tstamp timeout, callback)</dt> |
1624 | <dt>ev_once (loop, int fd, int events, ev_tstamp timeout, callback)</dt> |
1520 | <dd> |
1625 | <dd> |
… | |
… | |
1567 | |
1672 | |
1568 | |
1673 | |
1569 | |
1674 | |
1570 | |
1675 | |
1571 | </div> |
1676 | </div> |
1572 | <h1 id="LIBEVENT_EMULATION">LIBEVENT EMULATION</h1><p><a href="#TOP" class="toplink">Top</a></p> |
1677 | <h1 id="LIBEVENT_EMULATION">LIBEVENT EMULATION</h1> |
1573 | <div id="LIBEVENT_EMULATION_CONTENT"> |
1678 | <div id="LIBEVENT_EMULATION_CONTENT"> |
1574 | <p>Libev offers a compatibility emulation layer for libevent. It cannot |
1679 | <p>Libev offers a compatibility emulation layer for libevent. It cannot |
1575 | emulate the internals of libevent, so here are some usage hints:</p> |
1680 | emulate the internals of libevent, so here are some usage hints:</p> |
1576 | <dl> |
1681 | <dl> |
1577 | <dt>* Use it by including <event.h>, as usual.</dt> |
1682 | <dt>* Use it by including <event.h>, as usual.</dt> |
… | |
… | |
1587 | <dt>* The libev emulation is <i>not</i> ABI compatible to libevent, you need |
1692 | <dt>* The libev emulation is <i>not</i> ABI compatible to libevent, you need |
1588 | to use the libev header file and library.</dt> |
1693 | to use the libev header file and library.</dt> |
1589 | </dl> |
1694 | </dl> |
1590 | |
1695 | |
1591 | </div> |
1696 | </div> |
1592 | <h1 id="C_SUPPORT">C++ SUPPORT</h1><p><a href="#TOP" class="toplink">Top</a></p> |
1697 | <h1 id="C_SUPPORT">C++ SUPPORT</h1> |
1593 | <div id="C_SUPPORT_CONTENT"> |
1698 | <div id="C_SUPPORT_CONTENT"> |
1594 | <p>Libev comes with some simplistic wrapper classes for C++ that mainly allow |
1699 | <p>Libev comes with some simplistic wrapper classes for C++ that mainly allow |
1595 | you to use some convinience methods to start/stop watchers and also change |
1700 | you to use some convinience methods to start/stop watchers and also change |
1596 | the callback model to a model using method callbacks on objects.</p> |
1701 | the callback model to a model using method callbacks on objects.</p> |
1597 | <p>To use it,</p> |
1702 | <p>To use it,</p> |
… | |
… | |
1692 | |
1797 | |
1693 | |
1798 | |
1694 | </pre> |
1799 | </pre> |
1695 | |
1800 | |
1696 | </div> |
1801 | </div> |
1697 | <h1 id="MACRO_MAGIC">MACRO MAGIC</h1><p><a href="#TOP" class="toplink">Top</a></p> |
1802 | <h1 id="MACRO_MAGIC">MACRO MAGIC</h1> |
1698 | <div id="MACRO_MAGIC_CONTENT"> |
1803 | <div id="MACRO_MAGIC_CONTENT"> |
1699 | <p>Libev can be compiled with a variety of options, the most fundemantal is |
1804 | <p>Libev can be compiled with a variety of options, the most fundemantal is |
1700 | <code>EV_MULTIPLICITY</code>. This option determines wether (most) functions and |
1805 | <code>EV_MULTIPLICITY</code>. This option determines wether (most) functions and |
1701 | callbacks have an initial <code>struct ev_loop *</code> argument.</p> |
1806 | callbacks have an initial <code>struct ev_loop *</code> argument.</p> |
1702 | <p>To make it easier to write programs that cope with either variant, the |
1807 | <p>To make it easier to write programs that cope with either variant, the |
… | |
… | |
1734 | <dd> |
1839 | <dd> |
1735 | <p>Similar to the other two macros, this gives you the value of the default |
1840 | <p>Similar to the other two macros, this gives you the value of the default |
1736 | loop, if multiple loops are supported ("ev loop default").</p> |
1841 | loop, if multiple loops are supported ("ev loop default").</p> |
1737 | </dd> |
1842 | </dd> |
1738 | </dl> |
1843 | </dl> |
1739 | <p>Example: Declare and initialise a check watcher, working regardless of |
1844 | <p>Example: Declare and initialise a check watcher, utilising the above |
1740 | wether multiple loops are supported or not.</p> |
1845 | macros so it will work regardless of wether multiple loops are supported |
|
|
1846 | or not.</p> |
1741 | <pre> static void |
1847 | <pre> static void |
1742 | check_cb (EV_P_ ev_timer *w, int revents) |
1848 | check_cb (EV_P_ ev_timer *w, int revents) |
1743 | { |
1849 | { |
1744 | ev_check_stop (EV_A_ w); |
1850 | ev_check_stop (EV_A_ w); |
1745 | } |
1851 | } |
… | |
… | |
1747 | ev_check check; |
1853 | ev_check check; |
1748 | ev_check_init (&check, check_cb); |
1854 | ev_check_init (&check, check_cb); |
1749 | ev_check_start (EV_DEFAULT_ &check); |
1855 | ev_check_start (EV_DEFAULT_ &check); |
1750 | ev_loop (EV_DEFAULT_ 0); |
1856 | ev_loop (EV_DEFAULT_ 0); |
1751 | |
1857 | |
1752 | |
|
|
1753 | |
|
|
1754 | |
|
|
1755 | </pre> |
1858 | </pre> |
1756 | |
1859 | |
1757 | </div> |
1860 | </div> |
1758 | <h1 id="EMBEDDING">EMBEDDING</h1><p><a href="#TOP" class="toplink">Top</a></p> |
1861 | <h1 id="EMBEDDING">EMBEDDING</h1> |
1759 | <div id="EMBEDDING_CONTENT"> |
1862 | <div id="EMBEDDING_CONTENT"> |
1760 | <p>Libev can (and often is) directly embedded into host |
1863 | <p>Libev can (and often is) directly embedded into host |
1761 | applications. Examples of applications that embed it include the Deliantra |
1864 | applications. Examples of applications that embed it include the Deliantra |
1762 | Game Server, the EV perl module, the GNU Virtual Private Ethernet (gvpe) |
1865 | Game Server, the EV perl module, the GNU Virtual Private Ethernet (gvpe) |
1763 | and rxvt-unicode.</p> |
1866 | and rxvt-unicode.</p> |
… | |
… | |
1800 | ev_vars.h |
1903 | ev_vars.h |
1801 | ev_wrap.h |
1904 | ev_wrap.h |
1802 | |
1905 | |
1803 | ev_win32.c required on win32 platforms only |
1906 | ev_win32.c required on win32 platforms only |
1804 | |
1907 | |
1805 | ev_select.c only when select backend is enabled (which is by default) |
1908 | ev_select.c only when select backend is enabled (which is enabled by default) |
1806 | ev_poll.c only when poll backend is enabled (disabled by default) |
1909 | ev_poll.c only when poll backend is enabled (disabled by default) |
1807 | ev_epoll.c only when the epoll backend is enabled (disabled by default) |
1910 | ev_epoll.c only when the epoll backend is enabled (disabled by default) |
1808 | ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
1911 | ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
1809 | ev_port.c only when the solaris port backend is enabled (disabled by default) |
1912 | ev_port.c only when the solaris port backend is enabled (disabled by default) |
1810 | |
1913 | |
… | |
… | |
1937 | </dd> |
2040 | </dd> |
1938 | <dt>EV_USE_DEVPOLL</dt> |
2041 | <dt>EV_USE_DEVPOLL</dt> |
1939 | <dd> |
2042 | <dd> |
1940 | <p>reserved for future expansion, works like the USE symbols above.</p> |
2043 | <p>reserved for future expansion, works like the USE symbols above.</p> |
1941 | </dd> |
2044 | </dd> |
|
|
2045 | <dt>EV_USE_INOTIFY</dt> |
|
|
2046 | <dd> |
|
|
2047 | <p>If defined to be <code>1</code>, libev will compile in support for the Linux inotify |
|
|
2048 | interface to speed up <code>ev_stat</code> watchers. Its actual availability will |
|
|
2049 | be detected at runtime.</p> |
|
|
2050 | </dd> |
1942 | <dt>EV_H</dt> |
2051 | <dt>EV_H</dt> |
1943 | <dd> |
2052 | <dd> |
1944 | <p>The name of the <cite>ev.h</cite> header file used to include it. The default if |
2053 | <p>The name of the <cite>ev.h</cite> header file used to include it. The default if |
1945 | undefined is <code><ev.h></code> in <cite>event.h</cite> and <code>"ev.h"</code> in <cite>ev.c</cite>. This |
2054 | undefined is <code><ev.h></code> in <cite>event.h</cite> and <code>"ev.h"</code> in <cite>ev.c</cite>. This |
1946 | can be used to virtually rename the <cite>ev.h</cite> header file in case of conflicts.</p> |
2055 | can be used to virtually rename the <cite>ev.h</cite> header file in case of conflicts.</p> |
… | |
… | |
2001 | <dt>EV_PID_HASHSIZE</dt> |
2110 | <dt>EV_PID_HASHSIZE</dt> |
2002 | <dd> |
2111 | <dd> |
2003 | <p><code>ev_child</code> watchers use a small hash table to distribute workload by |
2112 | <p><code>ev_child</code> watchers use a small hash table to distribute workload by |
2004 | pid. The default size is <code>16</code> (or <code>1</code> with <code>EV_MINIMAL</code>), usually more |
2113 | pid. The default size is <code>16</code> (or <code>1</code> with <code>EV_MINIMAL</code>), usually more |
2005 | than enough. If you need to manage thousands of children you might want to |
2114 | than enough. If you need to manage thousands of children you might want to |
2006 | increase this value.</p> |
2115 | increase this value (<i>must</i> be a power of two).</p> |
|
|
2116 | </dd> |
|
|
2117 | <dt>EV_INOTIFY_HASHSIZE</dt> |
|
|
2118 | <dd> |
|
|
2119 | <p><code>ev_staz</code> watchers use a small hash table to distribute workload by |
|
|
2120 | inotify watch id. The default size is <code>16</code> (or <code>1</code> with <code>EV_MINIMAL</code>), |
|
|
2121 | usually more than enough. If you need to manage thousands of <code>ev_stat</code> |
|
|
2122 | watchers you might want to increase this value (<i>must</i> be a power of |
|
|
2123 | two).</p> |
2007 | </dd> |
2124 | </dd> |
2008 | <dt>EV_COMMON</dt> |
2125 | <dt>EV_COMMON</dt> |
2009 | <dd> |
2126 | <dd> |
2010 | <p>By default, all watchers have a <code>void *data</code> member. By redefining |
2127 | <p>By default, all watchers have a <code>void *data</code> member. By redefining |
2011 | this macro to a something else you can include more and other types of |
2128 | this macro to a something else you can include more and other types of |
… | |
… | |
2038 | the <cite>libev/</cite> subdirectory and includes them in the <cite>EV/EVAPI.h</cite> (public |
2155 | the <cite>libev/</cite> subdirectory and includes them in the <cite>EV/EVAPI.h</cite> (public |
2039 | interface) and <cite>EV.xs</cite> (implementation) files. Only the <cite>EV.xs</cite> file |
2156 | interface) and <cite>EV.xs</cite> (implementation) files. Only the <cite>EV.xs</cite> file |
2040 | will be compiled. It is pretty complex because it provides its own header |
2157 | will be compiled. It is pretty complex because it provides its own header |
2041 | file.</p> |
2158 | file.</p> |
2042 | <p>The usage in rxvt-unicode is simpler. It has a <cite>ev_cpp.h</cite> header file |
2159 | <p>The usage in rxvt-unicode is simpler. It has a <cite>ev_cpp.h</cite> header file |
2043 | that everybody includes and which overrides some autoconf choices:</p> |
2160 | that everybody includes and which overrides some configure choices:</p> |
|
|
2161 | <pre> #define EV_MINIMAL 1 |
2044 | <pre> #define EV_USE_POLL 0 |
2162 | #define EV_USE_POLL 0 |
2045 | #define EV_MULTIPLICITY 0 |
2163 | #define EV_MULTIPLICITY 0 |
2046 | #define EV_PERIODICS 0 |
2164 | #define EV_PERIODIC_ENABLE 0 |
|
|
2165 | #define EV_STAT_ENABLE 0 |
|
|
2166 | #define EV_FORK_ENABLE 0 |
2047 | #define EV_CONFIG_H <config.h> |
2167 | #define EV_CONFIG_H <config.h> |
|
|
2168 | #define EV_MINPRI 0 |
|
|
2169 | #define EV_MAXPRI 0 |
2048 | |
2170 | |
2049 | #include "ev++.h" |
2171 | #include "ev++.h" |
2050 | |
2172 | |
2051 | </pre> |
2173 | </pre> |
2052 | <p>And a <cite>ev_cpp.C</cite> implementation file that contains libev proper and is compiled:</p> |
2174 | <p>And a <cite>ev_cpp.C</cite> implementation file that contains libev proper and is compiled:</p> |
… | |
… | |
2057 | |
2179 | |
2058 | |
2180 | |
2059 | </pre> |
2181 | </pre> |
2060 | |
2182 | |
2061 | </div> |
2183 | </div> |
2062 | <h1 id="COMPLEXITIES">COMPLEXITIES</h1><p><a href="#TOP" class="toplink">Top</a></p> |
2184 | <h1 id="COMPLEXITIES">COMPLEXITIES</h1> |
2063 | <div id="COMPLEXITIES_CONTENT"> |
2185 | <div id="COMPLEXITIES_CONTENT"> |
2064 | <p>In this section the complexities of (many of) the algorithms used inside |
2186 | <p>In this section the complexities of (many of) the algorithms used inside |
2065 | libev will be explained. For complexity discussions about backends see the |
2187 | libev will be explained. For complexity discussions about backends see the |
2066 | documentation for <code>ev_default_init</code>.</p> |
2188 | documentation for <code>ev_default_init</code>.</p> |
2067 | <p> |
2189 | <p> |
2068 | <dl> |
2190 | <dl> |
2069 | <dt>Starting and stopping timer/periodic watchers: O(log skipped_other_timers)</dt> |
2191 | <dt>Starting and stopping timer/periodic watchers: O(log skipped_other_timers)</dt> |
2070 | <dt>Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)</dt> |
2192 | <dt>Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)</dt> |
2071 | <dt>Starting io/check/prepare/idle/signal/child watchers: O(1)</dt> |
2193 | <dt>Starting io/check/prepare/idle/signal/child watchers: O(1)</dt> |
2072 | <dt>Stopping check/prepare/idle watchers: O(1)</dt> |
2194 | <dt>Stopping check/prepare/idle watchers: O(1)</dt> |
2073 | <dt>Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % 16))</dt> |
2195 | <dt>Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))</dt> |
2074 | <dt>Finding the next timer per loop iteration: O(1)</dt> |
2196 | <dt>Finding the next timer per loop iteration: O(1)</dt> |
2075 | <dt>Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)</dt> |
2197 | <dt>Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)</dt> |
2076 | <dt>Activating one watcher: O(1)</dt> |
2198 | <dt>Activating one watcher: O(1)</dt> |
2077 | </dl> |
2199 | </dl> |
2078 | </p> |
2200 | </p> |
… | |
… | |
2080 | |
2202 | |
2081 | |
2203 | |
2082 | |
2204 | |
2083 | |
2205 | |
2084 | </div> |
2206 | </div> |
2085 | <h1 id="AUTHOR">AUTHOR</h1><p><a href="#TOP" class="toplink">Top</a></p> |
2207 | <h1 id="AUTHOR">AUTHOR</h1> |
2086 | <div id="AUTHOR_CONTENT"> |
2208 | <div id="AUTHOR_CONTENT"> |
2087 | <p>Marc Lehmann <libev@schmorp.de>.</p> |
2209 | <p>Marc Lehmann <libev@schmorp.de>.</p> |
2088 | |
2210 | |
2089 | </div> |
2211 | </div> |
2090 | </div></body> |
2212 | </div></body> |