… | |
… | |
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 09:11:42 2007" /> |
9 | <meta name="created" content="Wed Nov 28 12:27:27 2007" /> |
10 | <meta name="generator" content="Pod::Xhtml 1.57" /> |
10 | <meta name="generator" content="Pod::Xhtml 1.57" /> |
11 | <link rel="stylesheet" href="http://res.tst.eu/pod.css"/></head> |
11 | <link rel="stylesheet" href="http://res.tst.eu/pod.css"/></head> |
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> |
|
|
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> |
… | |
… | |
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> |
|
|
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> |
|
|
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> |
… | |
… | |
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> |
|
|
78 | <div id="EXAMPLE_PROGRAM_CONTENT"> |
|
|
79 | <pre> #include <ev.h> |
|
|
80 | |
|
|
81 | ev_io stdin_watcher; |
|
|
82 | ev_timer timeout_watcher; |
|
|
83 | |
|
|
84 | /* called when data readable on stdin */ |
|
|
85 | static void |
|
|
86 | stdin_cb (EV_P_ struct ev_io *w, int revents) |
|
|
87 | { |
|
|
88 | /* puts ("stdin ready"); */ |
|
|
89 | ev_io_stop (EV_A_ w); /* just a syntax example */ |
|
|
90 | ev_unloop (EV_A_ EVUNLOOP_ALL); /* leave all loop calls */ |
|
|
91 | } |
|
|
92 | |
|
|
93 | static void |
|
|
94 | timeout_cb (EV_P_ struct ev_timer *w, int revents) |
|
|
95 | { |
|
|
96 | /* puts ("timeout"); */ |
|
|
97 | ev_unloop (EV_A_ EVUNLOOP_ONE); /* leave one loop call */ |
|
|
98 | } |
|
|
99 | |
|
|
100 | int |
|
|
101 | main (void) |
|
|
102 | { |
|
|
103 | struct ev_loop *loop = ev_default_loop (0); |
|
|
104 | |
|
|
105 | /* initialise an io watcher, then start it */ |
|
|
106 | ev_io_init (&stdin_watcher, stdin_cb, /*STDIN_FILENO*/ 0, EV_READ); |
|
|
107 | ev_io_start (loop, &stdin_watcher); |
|
|
108 | |
|
|
109 | /* simple non-repeating 5.5 second timeout */ |
|
|
110 | ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.); |
|
|
111 | ev_timer_start (loop, &timeout_watcher); |
|
|
112 | |
|
|
113 | /* loop till timeout or data ready */ |
|
|
114 | ev_loop (loop, 0); |
|
|
115 | |
|
|
116 | return 0; |
|
|
117 | } |
|
|
118 | |
|
|
119 | </pre> |
|
|
120 | |
|
|
121 | </div> |
|
|
122 | <h1 id="DESCRIPTION">DESCRIPTION</h1> |
75 | <div id="DESCRIPTION_CONTENT"> |
123 | <div id="DESCRIPTION_CONTENT"> |
76 | <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 |
77 | 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 |
78 | these event sources and provide your program with events.</p> |
126 | 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 |
127 | <p>To do this, it must take more or less complete control over your process |
… | |
… | |
83 | 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 |
84 | 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 |
85 | watcher.</p> |
133 | watcher.</p> |
86 | |
134 | |
87 | </div> |
135 | </div> |
88 | <h1 id="FEATURES">FEATURES</h1><p><a href="#TOP" class="toplink">Top</a></p> |
136 | <h1 id="FEATURES">FEATURES</h1> |
89 | <div id="FEATURES_CONTENT"> |
137 | <div id="FEATURES_CONTENT"> |
90 | <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 |
91 | kqueue mechanisms for file descriptor events, relative timers, absolute |
139 | bsd-specific <code>kqueue</code> and the solaris-specific event port mechanisms |
92 | timers with customised rescheduling, signal events, process status change |
140 | for file descriptor events (<code>ev_io</code>), relative timers (<code>ev_timer</code>), |
93 | events (related to SIGCHLD), and event watchers dealing with the event |
141 | absolute timers with customised rescheduling (<code>ev_periodic</code>), synchronous |
94 | loop mechanism itself (idle, prepare and check watchers). It also is quite |
142 | signals (<code>ev_signal</code>), process status change events (<code>ev_child</code>), and |
|
|
143 | event watchers dealing with the event loop mechanism itself (<code>ev_idle</code>, |
|
|
144 | <code>ev_embed</code>, <code>ev_prepare</code> and <code>ev_check</code> watchers) as well as |
|
|
145 | file watchers (<code>ev_stat</code>) and even limited support for fork events |
|
|
146 | (<code>ev_fork</code>).</p> |
|
|
147 | <p>It also is quite fast (see this |
95 | fast (see this <a href="http://libev.schmorp.de/bench.html">benchmark</a> comparing |
148 | <a href="http://libev.schmorp.de/bench.html">benchmark</a> comparing it to libevent |
96 | it to libevent for example).</p> |
149 | for example).</p> |
97 | |
150 | |
98 | </div> |
151 | </div> |
99 | <h1 id="CONVENTIONS">CONVENTIONS</h1><p><a href="#TOP" class="toplink">Top</a></p> |
152 | <h1 id="CONVENTIONS">CONVENTIONS</h1> |
100 | <div id="CONVENTIONS_CONTENT"> |
153 | <div id="CONVENTIONS_CONTENT"> |
101 | <p>Libev is very configurable. In this manual the default configuration |
154 | <p>Libev is very configurable. In this manual the default configuration will |
102 | will be described, which supports multiple event loops. For more info |
155 | be described, which supports multiple event loops. For more info about |
103 | about various configuration options please have a look at the file |
156 | various configuration options please have a look at <strong>EMBED</strong> section in |
104 | <cite>README.embed</cite> in the libev distribution. If libev was configured without |
157 | this manual. If libev was configured without support for multiple event |
105 | support for multiple event loops, then all functions taking an initial |
158 | loops, then all functions taking an initial argument of name <code>loop</code> |
106 | argument of name <code>loop</code> (which is always of type <code>struct ev_loop *</code>) |
159 | (which is always of type <code>struct ev_loop *</code>) will not have this argument.</p> |
107 | will not have this argument.</p> |
|
|
108 | |
160 | |
109 | </div> |
161 | </div> |
110 | <h1 id="TIME_REPRESENTATION">TIME REPRESENTATION</h1><p><a href="#TOP" class="toplink">Top</a></p> |
162 | <h1 id="TIME_REPRESENTATION">TIME REPRESENTATION</h1> |
111 | <div id="TIME_REPRESENTATION_CONTENT"> |
163 | <div id="TIME_REPRESENTATION_CONTENT"> |
112 | <p>Libev represents time as a single floating point number, representing the |
164 | <p>Libev represents time as a single floating point number, representing the |
113 | (fractional) number of seconds since the (POSIX) epoch (somewhere near |
165 | (fractional) number of seconds since the (POSIX) epoch (somewhere near |
114 | the beginning of 1970, details are complicated, don't ask). This type is |
166 | the beginning of 1970, details are complicated, don't ask). This type is |
115 | called <code>ev_tstamp</code>, which is what you should use too. It usually aliases |
167 | called <code>ev_tstamp</code>, which is what you should use too. It usually aliases |
116 | to the <code>double</code> type in C, and when you need to do any calculations on |
168 | to the <code>double</code> type in C, and when you need to do any calculations on |
117 | it, you should treat it as such.</p> |
169 | it, you should treat it as such.</p> |
118 | |
170 | |
119 | |
|
|
120 | |
|
|
121 | |
|
|
122 | |
|
|
123 | </div> |
171 | </div> |
124 | <h1 id="GLOBAL_FUNCTIONS">GLOBAL FUNCTIONS</h1><p><a href="#TOP" class="toplink">Top</a></p> |
172 | <h1 id="GLOBAL_FUNCTIONS">GLOBAL FUNCTIONS</h1> |
125 | <div id="GLOBAL_FUNCTIONS_CONTENT"> |
173 | <div id="GLOBAL_FUNCTIONS_CONTENT"> |
126 | <p>These functions can be called anytime, even before initialising the |
174 | <p>These functions can be called anytime, even before initialising the |
127 | library in any way.</p> |
175 | library in any way.</p> |
128 | <dl> |
176 | <dl> |
129 | <dt>ev_tstamp ev_time ()</dt> |
177 | <dt>ev_tstamp ev_time ()</dt> |
… | |
… | |
142 | version of the library your program was compiled against.</p> |
190 | 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, |
191 | <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 |
192 | as this indicates an incompatible change. Minor versions are usually |
145 | compatible to older versions, so a larger minor version alone is usually |
193 | compatible to older versions, so a larger minor version alone is usually |
146 | not a problem.</p> |
194 | not a problem.</p> |
147 | <p>Example: make sure we haven't accidentally been linked against the wrong |
195 | <p>Example: Make sure we haven't accidentally been linked against the wrong |
148 | version:</p> |
196 | version.</p> |
149 | <pre> assert (("libev version mismatch", |
197 | <pre> assert (("libev version mismatch", |
150 | ev_version_major () == EV_VERSION_MAJOR |
198 | ev_version_major () == EV_VERSION_MAJOR |
151 | && ev_version_minor () >= EV_VERSION_MINOR)); |
199 | && ev_version_minor () >= EV_VERSION_MINOR)); |
152 | |
200 | |
153 | </pre> |
201 | </pre> |
… | |
… | |
181 | might be supported on the current system, you would need to look at |
229 | might be supported on the current system, you would need to look at |
182 | <code>ev_embeddable_backends () & ev_supported_backends ()</code>, likewise for |
230 | <code>ev_embeddable_backends () & ev_supported_backends ()</code>, likewise for |
183 | recommended ones.</p> |
231 | recommended ones.</p> |
184 | <p>See the description of <code>ev_embed</code> watchers for more info.</p> |
232 | <p>See the description of <code>ev_embed</code> watchers for more info.</p> |
185 | </dd> |
233 | </dd> |
186 | <dt>ev_set_allocator (void *(*cb)(void *ptr, long size))</dt> |
234 | <dt>ev_set_allocator (void *(*cb)(void *ptr, size_t size))</dt> |
187 | <dd> |
235 | <dd> |
188 | <p>Sets the allocation function to use (the prototype is similar to the |
236 | <p>Sets the allocation function to use (the prototype and semantics are |
189 | realloc C function, the semantics are identical). It is used to allocate |
237 | identical to the realloc C function). It is used to allocate and free |
190 | and free memory (no surprises here). If it returns zero when memory |
238 | memory (no surprises here). If it returns zero when memory needs to be |
191 | needs to be allocated, the library might abort or take some potentially |
239 | allocated, the library might abort or take some potentially destructive |
192 | destructive action. The default is your system realloc function.</p> |
240 | action. The default is your system realloc function.</p> |
193 | <p>You could override this function in high-availability programs to, say, |
241 | <p>You could override this function in high-availability programs to, say, |
194 | free some memory if it cannot allocate memory, to use a special allocator, |
242 | free some memory if it cannot allocate memory, to use a special allocator, |
195 | or even to sleep a while and retry until some memory is available.</p> |
243 | or even to sleep a while and retry until some memory is available.</p> |
196 | <p>Example: replace the libev allocator with one that waits a bit and then |
244 | <p>Example: Replace the libev allocator with one that waits a bit and then |
197 | retries: better than mine).</p> |
245 | retries).</p> |
198 | <pre> static void * |
246 | <pre> static void * |
199 | persistent_realloc (void *ptr, long size) |
247 | persistent_realloc (void *ptr, size_t size) |
200 | { |
248 | { |
201 | for (;;) |
249 | for (;;) |
202 | { |
250 | { |
203 | void *newptr = realloc (ptr, size); |
251 | void *newptr = realloc (ptr, size); |
204 | |
252 | |
… | |
… | |
221 | indicating the system call or subsystem causing the problem. If this |
269 | 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 |
270 | 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 |
271 | 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 |
272 | requested operation, or, if the condition doesn't go away, do bad stuff |
225 | (such as abort).</p> |
273 | (such as abort).</p> |
226 | <p>Example: do the same thing as libev does internally:</p> |
274 | <p>Example: This is basically the same thing that libev does internally, too.</p> |
227 | <pre> static void |
275 | <pre> static void |
228 | fatal_error (const char *msg) |
276 | fatal_error (const char *msg) |
229 | { |
277 | { |
230 | perror (msg); |
278 | perror (msg); |
231 | abort (); |
279 | abort (); |
… | |
… | |
237 | </pre> |
285 | </pre> |
238 | </dd> |
286 | </dd> |
239 | </dl> |
287 | </dl> |
240 | |
288 | |
241 | </div> |
289 | </div> |
242 | <h1 id="FUNCTIONS_CONTROLLING_THE_EVENT_LOOP">FUNCTIONS CONTROLLING THE EVENT LOOP</h1><p><a href="#TOP" class="toplink">Top</a></p> |
290 | <h1 id="FUNCTIONS_CONTROLLING_THE_EVENT_LOOP">FUNCTIONS CONTROLLING THE EVENT LOOP</h1> |
243 | <div id="FUNCTIONS_CONTROLLING_THE_EVENT_LOOP-2"> |
291 | <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 |
292 | <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 |
293 | types of such loops, the <i>default</i> loop, which supports signals and child |
246 | events, and dynamically created loops which do not.</p> |
294 | 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 |
295 | <p>If you use threads, a common model is to run the default event loop |
… | |
… | |
367 | <dd> |
415 | <dd> |
368 | <p>Similar to <code>ev_default_loop</code>, but always creates a new event loop that is |
416 | <p>Similar to <code>ev_default_loop</code>, but always creates a new event loop that is |
369 | always distinct from the default loop. Unlike the default loop, it cannot |
417 | always distinct from the default loop. Unlike the default loop, it cannot |
370 | handle signal and child watchers, and attempts to do so will be greeted by |
418 | handle signal and child watchers, and attempts to do so will be greeted by |
371 | undefined behaviour (or a failed assertion if assertions are enabled).</p> |
419 | 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> |
420 | <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); |
421 | <pre> struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
374 | if (!epoller) |
422 | if (!epoller) |
375 | fatal ("no epoll found here, maybe it hides under your chair"); |
423 | fatal ("no epoll found here, maybe it hides under your chair"); |
376 | |
424 | |
377 | </pre> |
425 | </pre> |
… | |
… | |
470 | be handled here by queueing them when their watcher gets executed. |
518 | be handled here by queueing them when their watcher gets executed. |
471 | - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
519 | - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
472 | were used, return, otherwise continue with step *. |
520 | were used, return, otherwise continue with step *. |
473 | |
521 | |
474 | </pre> |
522 | </pre> |
475 | <p>Example: queue some jobs and then loop until no events are outsanding |
523 | <p>Example: Queue some jobs and then loop until no events are outsanding |
476 | anymore.</p> |
524 | anymore.</p> |
477 | <pre> ... queue jobs here, make sure they register event watchers as long |
525 | <pre> ... queue jobs here, make sure they register event watchers as long |
478 | ... as they still have work to do (even an idle watcher will do..) |
526 | ... as they still have work to do (even an idle watcher will do..) |
479 | ev_loop (my_loop, 0); |
527 | ev_loop (my_loop, 0); |
480 | ... jobs done. yeah! |
528 | ... jobs done. yeah! |
… | |
… | |
499 | example, libev itself uses this for its internal signal pipe: It is not |
547 | example, libev itself uses this for its internal signal pipe: It is not |
500 | visible to the libev user and should not keep <code>ev_loop</code> from exiting if |
548 | visible to the libev user and should not keep <code>ev_loop</code> from exiting if |
501 | no event watchers registered by it are active. It is also an excellent |
549 | no event watchers registered by it are active. It is also an excellent |
502 | way to do this for generic recurring timers or from within third-party |
550 | way to do this for generic recurring timers or from within third-party |
503 | libraries. Just remember to <i>unref after start</i> and <i>ref before stop</i>.</p> |
551 | libraries. Just remember to <i>unref after start</i> and <i>ref before stop</i>.</p> |
504 | <p>Example: create a signal watcher, but keep it from keeping <code>ev_loop</code> |
552 | <p>Example: Create a signal watcher, but keep it from keeping <code>ev_loop</code> |
505 | running when nothing else is active.</p> |
553 | running when nothing else is active.</p> |
506 | <pre> struct dv_signal exitsig; |
554 | <pre> struct ev_signal exitsig; |
507 | ev_signal_init (&exitsig, sig_cb, SIGINT); |
555 | ev_signal_init (&exitsig, sig_cb, SIGINT); |
508 | ev_signal_start (myloop, &exitsig); |
556 | ev_signal_start (loop, &exitsig); |
509 | evf_unref (myloop); |
557 | evf_unref (loop); |
510 | |
558 | |
511 | </pre> |
559 | </pre> |
512 | <p>Example: for some weird reason, unregister the above signal handler again.</p> |
560 | <p>Example: For some weird reason, unregister the above signal handler again.</p> |
513 | <pre> ev_ref (myloop); |
561 | <pre> ev_ref (loop); |
514 | ev_signal_stop (myloop, &exitsig); |
562 | ev_signal_stop (loop, &exitsig); |
515 | |
563 | |
516 | </pre> |
564 | </pre> |
517 | </dd> |
565 | </dd> |
518 | </dl> |
566 | </dl> |
519 | |
567 | |
520 | |
568 | |
521 | |
569 | |
522 | |
570 | |
523 | |
571 | |
524 | </div> |
572 | </div> |
525 | <h1 id="ANATOMY_OF_A_WATCHER">ANATOMY OF A WATCHER</h1><p><a href="#TOP" class="toplink">Top</a></p> |
573 | <h1 id="ANATOMY_OF_A_WATCHER">ANATOMY OF A WATCHER</h1> |
526 | <div id="ANATOMY_OF_A_WATCHER_CONTENT"> |
574 | <div id="ANATOMY_OF_A_WATCHER_CONTENT"> |
527 | <p>A watcher is a structure that you create and register to record your |
575 | <p>A watcher is a structure that you create and register to record your |
528 | interest in some event. For instance, if you want to wait for STDIN to |
576 | interest in some event. For instance, if you want to wait for STDIN to |
529 | become readable, you would create an <code>ev_io</code> watcher for that:</p> |
577 | become readable, you would create an <code>ev_io</code> watcher for that:</p> |
530 | <pre> static void my_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
578 | <pre> static void my_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
… | |
… | |
606 | received events. Callbacks of both watcher types can start and stop as |
654 | received events. Callbacks of both watcher types can start and stop as |
607 | many watchers as they want, and all of them will be taken into account |
655 | many watchers as they want, and all of them will be taken into account |
608 | (for example, a <code>ev_prepare</code> watcher might start an idle watcher to keep |
656 | (for example, a <code>ev_prepare</code> watcher might start an idle watcher to keep |
609 | <code>ev_loop</code> from blocking).</p> |
657 | <code>ev_loop</code> from blocking).</p> |
610 | </dd> |
658 | </dd> |
|
|
659 | <dt><code>EV_EMBED</code></dt> |
|
|
660 | <dd> |
|
|
661 | <p>The embedded event loop specified in the <code>ev_embed</code> watcher needs attention.</p> |
|
|
662 | </dd> |
|
|
663 | <dt><code>EV_FORK</code></dt> |
|
|
664 | <dd> |
|
|
665 | <p>The event loop has been resumed in the child process after fork (see |
|
|
666 | <code>ev_fork</code>).</p> |
|
|
667 | </dd> |
611 | <dt><code>EV_ERROR</code></dt> |
668 | <dt><code>EV_ERROR</code></dt> |
612 | <dd> |
669 | <dd> |
613 | <p>An unspecified error has occured, the watcher has been stopped. This might |
670 | <p>An unspecified error has occured, the watcher has been stopped. This might |
614 | happen because the watcher could not be properly started because libev |
671 | 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 |
672 | ran out of memory, a file descriptor was found to be closed or any other |
… | |
… | |
684 | events but its callback has not yet been invoked). As long as a watcher |
741 | events but its callback has not yet been invoked). As long as a watcher |
685 | is pending (but not active) you must not call an init function on it (but |
742 | is pending (but not active) you must not call an init function on it (but |
686 | <code>ev_TYPE_set</code> is safe) and you must make sure the watcher is available to |
743 | <code>ev_TYPE_set</code> is safe) and you must make sure the watcher is available to |
687 | libev (e.g. you cnanot <code>free ()</code> it).</p> |
744 | libev (e.g. you cnanot <code>free ()</code> it).</p> |
688 | </dd> |
745 | </dd> |
689 | <dt>callback = ev_cb (ev_TYPE *watcher)</dt> |
746 | <dt>callback ev_cb (ev_TYPE *watcher)</dt> |
690 | <dd> |
747 | <dd> |
691 | <p>Returns the callback currently set on the watcher.</p> |
748 | <p>Returns the callback currently set on the watcher.</p> |
692 | </dd> |
749 | </dd> |
693 | <dt>ev_cb_set (ev_TYPE *watcher, callback)</dt> |
750 | <dt>ev_cb_set (ev_TYPE *watcher, callback)</dt> |
694 | <dd> |
751 | <dd> |
… | |
… | |
726 | struct my_io *w = (struct my_io *)w_; |
783 | struct my_io *w = (struct my_io *)w_; |
727 | ... |
784 | ... |
728 | } |
785 | } |
729 | |
786 | |
730 | </pre> |
787 | </pre> |
731 | <p>More interesting and less C-conformant ways of catsing your callback type |
788 | <p>More interesting and less C-conformant ways of casting your callback type |
732 | have been omitted....</p> |
789 | instead have been omitted.</p> |
|
|
790 | <p>Another common scenario is having some data structure with multiple |
|
|
791 | watchers:</p> |
|
|
792 | <pre> struct my_biggy |
|
|
793 | { |
|
|
794 | int some_data; |
|
|
795 | ev_timer t1; |
|
|
796 | ev_timer t2; |
|
|
797 | } |
733 | |
798 | |
|
|
799 | </pre> |
|
|
800 | <p>In this case getting the pointer to <code>my_biggy</code> is a bit more complicated, |
|
|
801 | you need to use <code>offsetof</code>:</p> |
|
|
802 | <pre> #include <stddef.h> |
734 | |
803 | |
|
|
804 | static void |
|
|
805 | t1_cb (EV_P_ struct ev_timer *w, int revents) |
|
|
806 | { |
|
|
807 | struct my_biggy big = (struct my_biggy * |
|
|
808 | (((char *)w) - offsetof (struct my_biggy, t1)); |
|
|
809 | } |
735 | |
810 | |
|
|
811 | static void |
|
|
812 | t2_cb (EV_P_ struct ev_timer *w, int revents) |
|
|
813 | { |
|
|
814 | struct my_biggy big = (struct my_biggy * |
|
|
815 | (((char *)w) - offsetof (struct my_biggy, t2)); |
|
|
816 | } |
736 | |
817 | |
737 | |
818 | |
|
|
819 | |
|
|
820 | |
|
|
821 | </pre> |
|
|
822 | |
738 | </div> |
823 | </div> |
739 | <h1 id="WATCHER_TYPES">WATCHER TYPES</h1><p><a href="#TOP" class="toplink">Top</a></p> |
824 | <h1 id="WATCHER_TYPES">WATCHER TYPES</h1> |
740 | <div id="WATCHER_TYPES_CONTENT"> |
825 | <div id="WATCHER_TYPES_CONTENT"> |
741 | <p>This section describes each watcher in detail, but will not repeat |
826 | <p>This section describes each watcher in detail, but will not repeat |
742 | information given in the last section. Any initialisation/set macros, |
827 | information given in the last section. Any initialisation/set macros, |
743 | functions and members specific to the watcher type are explained.</p> |
828 | 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, |
829 | <p>Members are additionally marked with either <i>[read-only]</i>, meaning that, |
… | |
… | |
804 | <dt>int events [read-only]</dt> |
889 | <dt>int events [read-only]</dt> |
805 | <dd> |
890 | <dd> |
806 | <p>The events being watched.</p> |
891 | <p>The events being watched.</p> |
807 | </dd> |
892 | </dd> |
808 | </dl> |
893 | </dl> |
809 | <p>Example: call <code>stdin_readable_cb</code> when STDIN_FILENO has become, well |
894 | <p>Example: Call <code>stdin_readable_cb</code> when STDIN_FILENO has become, well |
810 | readable, but only once. Since it is likely line-buffered, you could |
895 | readable, but only once. Since it is likely line-buffered, you could |
811 | attempt to read a whole line in the callback:</p> |
896 | attempt to read a whole line in the callback.</p> |
812 | <pre> static void |
897 | <pre> static void |
813 | stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
898 | stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
814 | { |
899 | { |
815 | ev_io_stop (loop, w); |
900 | ev_io_stop (loop, w); |
816 | .. read from stdin here (or from w->fd) and haqndle any I/O errors |
901 | .. read from stdin here (or from w->fd) and haqndle any I/O errors |
… | |
… | |
899 | <p>The current <code>repeat</code> value. Will be used each time the watcher times out |
984 | <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), |
985 | 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> |
986 | which is also when any modifications are taken into account.</p> |
902 | </dd> |
987 | </dd> |
903 | </dl> |
988 | </dl> |
904 | <p>Example: create a timer that fires after 60 seconds.</p> |
989 | <p>Example: Create a timer that fires after 60 seconds.</p> |
905 | <pre> static void |
990 | <pre> static void |
906 | one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
991 | one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
907 | { |
992 | { |
908 | .. one minute over, w is actually stopped right here |
993 | .. one minute over, w is actually stopped right here |
909 | } |
994 | } |
… | |
… | |
911 | struct ev_timer mytimer; |
996 | struct ev_timer mytimer; |
912 | ev_timer_init (&mytimer, one_minute_cb, 60., 0.); |
997 | ev_timer_init (&mytimer, one_minute_cb, 60., 0.); |
913 | ev_timer_start (loop, &mytimer); |
998 | ev_timer_start (loop, &mytimer); |
914 | |
999 | |
915 | </pre> |
1000 | </pre> |
916 | <p>Example: create a timeout timer that times out after 10 seconds of |
1001 | <p>Example: Create a timeout timer that times out after 10 seconds of |
917 | inactivity.</p> |
1002 | inactivity.</p> |
918 | <pre> static void |
1003 | <pre> static void |
919 | timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1004 | timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
920 | { |
1005 | { |
921 | .. ten seconds without any activity |
1006 | .. ten seconds without any activity |
… | |
… | |
1037 | <p>The current reschedule callback, or <code>0</code>, if this functionality is |
1122 | <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 |
1123 | 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> |
1124 | the periodic timer fires or <code>ev_periodic_again</code> is being called.</p> |
1040 | </dd> |
1125 | </dd> |
1041 | </dl> |
1126 | </dl> |
1042 | <p>Example: call a callback every hour, or, more precisely, whenever the |
1127 | <p>Example: Call a callback every hour, or, more precisely, whenever the |
1043 | system clock is divisible by 3600. The callback invocation times have |
1128 | system clock is divisible by 3600. The callback invocation times have |
1044 | potentially a lot of jittering, but good long-term stability.</p> |
1129 | potentially a lot of jittering, but good long-term stability.</p> |
1045 | <pre> static void |
1130 | <pre> static void |
1046 | clock_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
1131 | clock_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
1047 | { |
1132 | { |
… | |
… | |
1051 | struct ev_periodic hourly_tick; |
1136 | struct ev_periodic hourly_tick; |
1052 | ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); |
1137 | ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); |
1053 | ev_periodic_start (loop, &hourly_tick); |
1138 | ev_periodic_start (loop, &hourly_tick); |
1054 | |
1139 | |
1055 | </pre> |
1140 | </pre> |
1056 | <p>Example: the same as above, but use a reschedule callback to do it:</p> |
1141 | <p>Example: The same as above, but use a reschedule callback to do it:</p> |
1057 | <pre> #include <math.h> |
1142 | <pre> #include <math.h> |
1058 | |
1143 | |
1059 | static ev_tstamp |
1144 | static ev_tstamp |
1060 | my_scheduler_cb (struct ev_periodic *w, ev_tstamp now) |
1145 | my_scheduler_cb (struct ev_periodic *w, ev_tstamp now) |
1061 | { |
1146 | { |
… | |
… | |
1063 | } |
1148 | } |
1064 | |
1149 | |
1065 | ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); |
1150 | ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); |
1066 | |
1151 | |
1067 | </pre> |
1152 | </pre> |
1068 | <p>Example: call a callback every hour, starting now:</p> |
1153 | <p>Example: Call a callback every hour, starting now:</p> |
1069 | <pre> struct ev_periodic hourly_tick; |
1154 | <pre> struct ev_periodic hourly_tick; |
1070 | ev_periodic_init (&hourly_tick, clock_cb, |
1155 | ev_periodic_init (&hourly_tick, clock_cb, |
1071 | fmod (ev_now (loop), 3600.), 3600., 0); |
1156 | fmod (ev_now (loop), 3600.), 3600., 0); |
1072 | ev_periodic_start (loop, &hourly_tick); |
1157 | ev_periodic_start (loop, &hourly_tick); |
1073 | |
1158 | |
… | |
… | |
1134 | <dd> |
1219 | <dd> |
1135 | <p>The process exit/trace status caused by <code>rpid</code> (see your systems |
1220 | <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> |
1221 | <code>waitpid</code> and <code>sys/wait.h</code> documentation for details).</p> |
1137 | </dd> |
1222 | </dd> |
1138 | </dl> |
1223 | </dl> |
1139 | <p>Example: try to exit cleanly on SIGINT and SIGTERM.</p> |
1224 | <p>Example: Try to exit cleanly on SIGINT and SIGTERM.</p> |
1140 | <pre> static void |
1225 | <pre> static void |
1141 | sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
1226 | sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
1142 | { |
1227 | { |
1143 | ev_unloop (loop, EVUNLOOP_ALL); |
1228 | ev_unloop (loop, EVUNLOOP_ALL); |
1144 | } |
1229 | } |
… | |
… | |
1162 | not exist" is a status change like any other. The condition "path does |
1247 | 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 |
1248 | 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 |
1249 | otherwise always forced to be at least one) and all the other fields of |
1165 | the stat buffer having unspecified contents.</p> |
1250 | the stat buffer having unspecified contents.</p> |
1166 | <p>Since there is no standard to do this, the portable implementation simply |
1251 | <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 |
1252 | 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 |
1253 | 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, |
1254 | 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 |
1255 | 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 |
1256 | 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 |
1257 | impose a minimum interval which is currently around <code>0.1</code>, but thats |
1173 | usually overkill.</p> |
1258 | usually overkill.</p> |
1174 | <p>This watcher type is not meant for massive numbers of stat watchers, |
1259 | <p>This watcher type is not meant for massive numbers of stat watchers, |
1175 | as even with OS-supported change notifications, this can be |
1260 | as even with OS-supported change notifications, this can be |
1176 | resource-intensive.</p> |
1261 | resource-intensive.</p> |
1177 | <p>At the time of this writing, no specific OS backends are implemented, but |
1262 | <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> |
1263 | implemented (implementing kqueue support is left as an exercise for the |
|
|
1264 | reader). Inotify will be used to give hints only and should not change the |
|
|
1265 | semantics of <code>ev_stat</code> watchers, which means that libev sometimes needs |
|
|
1266 | to fall back to regular polling again even with inotify, but changes are |
|
|
1267 | usually detected immediately, and if the file exists there will be no |
|
|
1268 | polling.</p> |
1179 | <dl> |
1269 | <dl> |
1180 | <dt>ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)</dt> |
1270 | <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> |
1271 | <dt>ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)</dt> |
1182 | <dd> |
1272 | <dd> |
1183 | <p>Configures the watcher to wait for status changes of the given |
1273 | <p>Configures the watcher to wait for status changes of the given |
… | |
… | |
1267 | <p>Initialises and configures the idle watcher - it has no parameters of any |
1357 | <p>Initialises and configures the idle watcher - it has no parameters of any |
1268 | kind. There is a <code>ev_idle_set</code> macro, but using it is utterly pointless, |
1358 | kind. There is a <code>ev_idle_set</code> macro, but using it is utterly pointless, |
1269 | believe me.</p> |
1359 | believe me.</p> |
1270 | </dd> |
1360 | </dd> |
1271 | </dl> |
1361 | </dl> |
1272 | <p>Example: dynamically allocate an <code>ev_idle</code>, start it, and in the |
1362 | <p>Example: Dynamically allocate an <code>ev_idle</code> watcher, start it, and in the |
1273 | callback, free it. Alos, use no error checking, as usual.</p> |
1363 | callback, free it. Also, use no error checking, as usual.</p> |
1274 | <pre> static void |
1364 | <pre> static void |
1275 | idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
1365 | idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
1276 | { |
1366 | { |
1277 | free (w); |
1367 | free (w); |
1278 | // now do something you wanted to do when the program has |
1368 | // now do something you wanted to do when the program has |
… | |
… | |
1480 | |
1570 | |
1481 | |
1571 | |
1482 | |
1572 | |
1483 | |
1573 | |
1484 | </div> |
1574 | </div> |
1485 | <h1 id="OTHER_FUNCTIONS">OTHER FUNCTIONS</h1><p><a href="#TOP" class="toplink">Top</a></p> |
1575 | <h2 id="code_ev_fork_code_the_audacity_to_re"><code>ev_fork</code> - the audacity to resume the event loop after a fork</h2> |
|
|
1576 | <div id="code_ev_fork_code_the_audacity_to_re-2"> |
|
|
1577 | <p>Fork watchers are called when a <code>fork ()</code> was detected (usually because |
|
|
1578 | whoever is a good citizen cared to tell libev about it by calling |
|
|
1579 | <code>ev_default_fork</code> or <code>ev_loop_fork</code>). The invocation is done before the |
|
|
1580 | event loop blocks next and before <code>ev_check</code> watchers are being called, |
|
|
1581 | and only in the child after the fork. If whoever good citizen calling |
|
|
1582 | <code>ev_default_fork</code> cheats and calls it in the wrong process, the fork |
|
|
1583 | handlers will be invoked, too, of course.</p> |
|
|
1584 | <dl> |
|
|
1585 | <dt>ev_fork_init (ev_signal *, callback)</dt> |
|
|
1586 | <dd> |
|
|
1587 | <p>Initialises and configures the fork watcher - it has no parameters of any |
|
|
1588 | kind. There is a <code>ev_fork_set</code> macro, but using it is utterly pointless, |
|
|
1589 | believe me.</p> |
|
|
1590 | </dd> |
|
|
1591 | </dl> |
|
|
1592 | |
|
|
1593 | |
|
|
1594 | |
|
|
1595 | |
|
|
1596 | |
|
|
1597 | </div> |
|
|
1598 | <h1 id="OTHER_FUNCTIONS">OTHER FUNCTIONS</h1> |
1486 | <div id="OTHER_FUNCTIONS_CONTENT"> |
1599 | <div id="OTHER_FUNCTIONS_CONTENT"> |
1487 | <p>There are some other functions of possible interest. Described. Here. Now.</p> |
1600 | <p>There are some other functions of possible interest. Described. Here. Now.</p> |
1488 | <dl> |
1601 | <dl> |
1489 | <dt>ev_once (loop, int fd, int events, ev_tstamp timeout, callback)</dt> |
1602 | <dt>ev_once (loop, int fd, int events, ev_tstamp timeout, callback)</dt> |
1490 | <dd> |
1603 | <dd> |
… | |
… | |
1537 | |
1650 | |
1538 | |
1651 | |
1539 | |
1652 | |
1540 | |
1653 | |
1541 | </div> |
1654 | </div> |
1542 | <h1 id="LIBEVENT_EMULATION">LIBEVENT EMULATION</h1><p><a href="#TOP" class="toplink">Top</a></p> |
1655 | <h1 id="LIBEVENT_EMULATION">LIBEVENT EMULATION</h1> |
1543 | <div id="LIBEVENT_EMULATION_CONTENT"> |
1656 | <div id="LIBEVENT_EMULATION_CONTENT"> |
1544 | <p>Libev offers a compatibility emulation layer for libevent. It cannot |
1657 | <p>Libev offers a compatibility emulation layer for libevent. It cannot |
1545 | emulate the internals of libevent, so here are some usage hints:</p> |
1658 | emulate the internals of libevent, so here are some usage hints:</p> |
1546 | <dl> |
1659 | <dl> |
1547 | <dt>* Use it by including <event.h>, as usual.</dt> |
1660 | <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 |
1670 | <dt>* The libev emulation is <i>not</i> ABI compatible to libevent, you need |
1558 | to use the libev header file and library.</dt> |
1671 | to use the libev header file and library.</dt> |
1559 | </dl> |
1672 | </dl> |
1560 | |
1673 | |
1561 | </div> |
1674 | </div> |
1562 | <h1 id="C_SUPPORT">C++ SUPPORT</h1><p><a href="#TOP" class="toplink">Top</a></p> |
1675 | <h1 id="C_SUPPORT">C++ SUPPORT</h1> |
1563 | <div id="C_SUPPORT_CONTENT"> |
1676 | <div id="C_SUPPORT_CONTENT"> |
1564 | <p>Libev comes with some simplistic wrapper classes for C++ that mainly allow |
1677 | <p>Libev comes with some simplistic wrapper classes for C++ that mainly allow |
1565 | you to use some convinience methods to start/stop watchers and also change |
1678 | you to use some convinience methods to start/stop watchers and also change |
1566 | the callback model to a model using method callbacks on objects.</p> |
1679 | the callback model to a model using method callbacks on objects.</p> |
1567 | <p>To use it,</p> |
1680 | <p>To use it,</p> |
… | |
… | |
1631 | </dd> |
1744 | </dd> |
1632 | <dt>w->sweep () <code>ev::embed</code> only</dt> |
1745 | <dt>w->sweep () <code>ev::embed</code> only</dt> |
1633 | <dd> |
1746 | <dd> |
1634 | <p>Invokes <code>ev_embed_sweep</code>.</p> |
1747 | <p>Invokes <code>ev_embed_sweep</code>.</p> |
1635 | </dd> |
1748 | </dd> |
|
|
1749 | <dt>w->update () <code>ev::stat</code> only</dt> |
|
|
1750 | <dd> |
|
|
1751 | <p>Invokes <code>ev_stat_stat</code>.</p> |
|
|
1752 | </dd> |
1636 | </dl> |
1753 | </dl> |
1637 | </p> |
1754 | </p> |
1638 | </dd> |
1755 | </dd> |
1639 | </dl> |
1756 | </dl> |
1640 | <p>Example: Define a class with an IO and idle watcher, start one of them in |
1757 | <p>Example: Define a class with an IO and idle watcher, start one of them in |
… | |
… | |
1652 | idle (this, &myclass::idle_cb) |
1769 | idle (this, &myclass::idle_cb) |
1653 | { |
1770 | { |
1654 | io.start (fd, ev::READ); |
1771 | io.start (fd, ev::READ); |
1655 | } |
1772 | } |
1656 | |
1773 | |
1657 | </pre> |
|
|
1658 | |
1774 | |
|
|
1775 | |
|
|
1776 | |
|
|
1777 | </pre> |
|
|
1778 | |
1659 | </div> |
1779 | </div> |
1660 | <h1 id="EMBEDDING">EMBEDDING</h1><p><a href="#TOP" class="toplink">Top</a></p> |
1780 | <h1 id="MACRO_MAGIC">MACRO MAGIC</h1> |
|
|
1781 | <div id="MACRO_MAGIC_CONTENT"> |
|
|
1782 | <p>Libev can be compiled with a variety of options, the most fundemantal is |
|
|
1783 | <code>EV_MULTIPLICITY</code>. This option determines wether (most) functions and |
|
|
1784 | callbacks have an initial <code>struct ev_loop *</code> argument.</p> |
|
|
1785 | <p>To make it easier to write programs that cope with either variant, the |
|
|
1786 | following macros are defined:</p> |
|
|
1787 | <dl> |
|
|
1788 | <dt><code>EV_A</code>, <code>EV_A_</code></dt> |
|
|
1789 | <dd> |
|
|
1790 | <p>This provides the loop <i>argument</i> for functions, if one is required ("ev |
|
|
1791 | loop argument"). The <code>EV_A</code> form is used when this is the sole argument, |
|
|
1792 | <code>EV_A_</code> is used when other arguments are following. Example:</p> |
|
|
1793 | <pre> ev_unref (EV_A); |
|
|
1794 | ev_timer_add (EV_A_ watcher); |
|
|
1795 | ev_loop (EV_A_ 0); |
|
|
1796 | |
|
|
1797 | </pre> |
|
|
1798 | <p>It assumes the variable <code>loop</code> of type <code>struct ev_loop *</code> is in scope, |
|
|
1799 | which is often provided by the following macro.</p> |
|
|
1800 | </dd> |
|
|
1801 | <dt><code>EV_P</code>, <code>EV_P_</code></dt> |
|
|
1802 | <dd> |
|
|
1803 | <p>This provides the loop <i>parameter</i> for functions, if one is required ("ev |
|
|
1804 | loop parameter"). The <code>EV_P</code> form is used when this is the sole parameter, |
|
|
1805 | <code>EV_P_</code> is used when other parameters are following. Example:</p> |
|
|
1806 | <pre> // this is how ev_unref is being declared |
|
|
1807 | static void ev_unref (EV_P); |
|
|
1808 | |
|
|
1809 | // this is how you can declare your typical callback |
|
|
1810 | static void cb (EV_P_ ev_timer *w, int revents) |
|
|
1811 | |
|
|
1812 | </pre> |
|
|
1813 | <p>It declares a parameter <code>loop</code> of type <code>struct ev_loop *</code>, quite |
|
|
1814 | suitable for use with <code>EV_A</code>.</p> |
|
|
1815 | </dd> |
|
|
1816 | <dt><code>EV_DEFAULT</code>, <code>EV_DEFAULT_</code></dt> |
|
|
1817 | <dd> |
|
|
1818 | <p>Similar to the other two macros, this gives you the value of the default |
|
|
1819 | loop, if multiple loops are supported ("ev loop default").</p> |
|
|
1820 | </dd> |
|
|
1821 | </dl> |
|
|
1822 | <p>Example: Declare and initialise a check watcher, working regardless of |
|
|
1823 | wether multiple loops are supported or not.</p> |
|
|
1824 | <pre> static void |
|
|
1825 | check_cb (EV_P_ ev_timer *w, int revents) |
|
|
1826 | { |
|
|
1827 | ev_check_stop (EV_A_ w); |
|
|
1828 | } |
|
|
1829 | |
|
|
1830 | ev_check check; |
|
|
1831 | ev_check_init (&check, check_cb); |
|
|
1832 | ev_check_start (EV_DEFAULT_ &check); |
|
|
1833 | ev_loop (EV_DEFAULT_ 0); |
|
|
1834 | |
|
|
1835 | |
|
|
1836 | |
|
|
1837 | |
|
|
1838 | </pre> |
|
|
1839 | |
|
|
1840 | </div> |
|
|
1841 | <h1 id="EMBEDDING">EMBEDDING</h1> |
1661 | <div id="EMBEDDING_CONTENT"> |
1842 | <div id="EMBEDDING_CONTENT"> |
1662 | <p>Libev can (and often is) directly embedded into host |
1843 | <p>Libev can (and often is) directly embedded into host |
1663 | applications. Examples of applications that embed it include the Deliantra |
1844 | applications. Examples of applications that embed it include the Deliantra |
1664 | Game Server, the EV perl module, the GNU Virtual Private Ethernet (gvpe) |
1845 | Game Server, the EV perl module, the GNU Virtual Private Ethernet (gvpe) |
1665 | and rxvt-unicode.</p> |
1846 | and rxvt-unicode.</p> |
… | |
… | |
1839 | </dd> |
2020 | </dd> |
1840 | <dt>EV_USE_DEVPOLL</dt> |
2021 | <dt>EV_USE_DEVPOLL</dt> |
1841 | <dd> |
2022 | <dd> |
1842 | <p>reserved for future expansion, works like the USE symbols above.</p> |
2023 | <p>reserved for future expansion, works like the USE symbols above.</p> |
1843 | </dd> |
2024 | </dd> |
|
|
2025 | <dt>EV_USE_INOTIFY</dt> |
|
|
2026 | <dd> |
|
|
2027 | <p>If defined to be <code>1</code>, libev will compile in support for the Linux inotify |
|
|
2028 | interface to speed up <code>ev_stat</code> watchers. Its actual availability will |
|
|
2029 | be detected at runtime.</p> |
|
|
2030 | </dd> |
1844 | <dt>EV_H</dt> |
2031 | <dt>EV_H</dt> |
1845 | <dd> |
2032 | <dd> |
1846 | <p>The name of the <cite>ev.h</cite> header file used to include it. The default if |
2033 | <p>The name of the <cite>ev.h</cite> header file used to include it. The default if |
1847 | undefined is <code><ev.h></code> in <cite>event.h</cite> and <code>"ev.h"</code> in <cite>ev.c</cite>. This |
2034 | undefined is <code><ev.h></code> in <cite>event.h</cite> and <code>"ev.h"</code> in <cite>ev.c</cite>. This |
1848 | can be used to virtually rename the <cite>ev.h</cite> header file in case of conflicts.</p> |
2035 | can be used to virtually rename the <cite>ev.h</cite> header file in case of conflicts.</p> |
… | |
… | |
1887 | <dt>EV_STAT_ENABLE</dt> |
2074 | <dt>EV_STAT_ENABLE</dt> |
1888 | <dd> |
2075 | <dd> |
1889 | <p>If undefined or defined to be <code>1</code>, then stat watchers are supported. If |
2076 | <p>If undefined or defined to be <code>1</code>, then stat watchers are supported. If |
1890 | defined to be <code>0</code>, then they are not.</p> |
2077 | defined to be <code>0</code>, then they are not.</p> |
1891 | </dd> |
2078 | </dd> |
|
|
2079 | <dt>EV_FORK_ENABLE</dt> |
|
|
2080 | <dd> |
|
|
2081 | <p>If undefined or defined to be <code>1</code>, then fork watchers are supported. If |
|
|
2082 | defined to be <code>0</code>, then they are not.</p> |
|
|
2083 | </dd> |
1892 | <dt>EV_MINIMAL</dt> |
2084 | <dt>EV_MINIMAL</dt> |
1893 | <dd> |
2085 | <dd> |
1894 | <p>If you need to shave off some kilobytes of code at the expense of some |
2086 | <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 |
2087 | 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> |
2088 | some inlining decisions, saves roughly 30% codesize of amd64.</p> |
|
|
2089 | </dd> |
|
|
2090 | <dt>EV_PID_HASHSIZE</dt> |
|
|
2091 | <dd> |
|
|
2092 | <p><code>ev_child</code> watchers use a small hash table to distribute workload by |
|
|
2093 | pid. The default size is <code>16</code> (or <code>1</code> with <code>EV_MINIMAL</code>), usually more |
|
|
2094 | than enough. If you need to manage thousands of children you might want to |
|
|
2095 | increase this value (<i>must</i> be a power of two).</p> |
|
|
2096 | </dd> |
|
|
2097 | <dt>EV_INOTIFY_HASHSIZE</dt> |
|
|
2098 | <dd> |
|
|
2099 | <p><code>ev_staz</code> watchers use a small hash table to distribute workload by |
|
|
2100 | inotify watch id. The default size is <code>16</code> (or <code>1</code> with <code>EV_MINIMAL</code>), |
|
|
2101 | usually more than enough. If you need to manage thousands of <code>ev_stat</code> |
|
|
2102 | watchers you might want to increase this value (<i>must</i> be a power of |
|
|
2103 | two).</p> |
1897 | </dd> |
2104 | </dd> |
1898 | <dt>EV_COMMON</dt> |
2105 | <dt>EV_COMMON</dt> |
1899 | <dd> |
2106 | <dd> |
1900 | <p>By default, all watchers have a <code>void *data</code> member. By redefining |
2107 | <p>By default, all watchers have a <code>void *data</code> member. By redefining |
1901 | this macro to a something else you can include more and other types of |
2108 | this macro to a something else you can include more and other types of |
… | |
… | |
1947 | |
2154 | |
1948 | |
2155 | |
1949 | </pre> |
2156 | </pre> |
1950 | |
2157 | |
1951 | </div> |
2158 | </div> |
1952 | <h1 id="COMPLEXITIES">COMPLEXITIES</h1><p><a href="#TOP" class="toplink">Top</a></p> |
2159 | <h1 id="COMPLEXITIES">COMPLEXITIES</h1> |
1953 | <div id="COMPLEXITIES_CONTENT"> |
2160 | <div id="COMPLEXITIES_CONTENT"> |
1954 | <p>In this section the complexities of (many of) the algorithms used inside |
2161 | <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 |
2162 | libev will be explained. For complexity discussions about backends see the |
1956 | documentation for <code>ev_default_init</code>.</p> |
2163 | documentation for <code>ev_default_init</code>.</p> |
1957 | <p> |
2164 | <p> |
1958 | <dl> |
2165 | <dl> |
1959 | <dt>Starting and stopping timer/periodic watchers: O(log skipped_other_timers)</dt> |
2166 | <dt>Starting and stopping timer/periodic watchers: O(log skipped_other_timers)</dt> |
1960 | <dt>Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)</dt> |
2167 | <dt>Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)</dt> |
1961 | <dt>Starting io/check/prepare/idle/signal/child watchers: O(1)</dt> |
2168 | <dt>Starting io/check/prepare/idle/signal/child watchers: O(1)</dt> |
1962 | <dt>Stopping check/prepare/idle watchers: O(1)</dt> |
2169 | <dt>Stopping check/prepare/idle watchers: O(1)</dt> |
1963 | <dt>Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % 16))</dt> |
2170 | <dt>Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))</dt> |
1964 | <dt>Finding the next timer per loop iteration: O(1)</dt> |
2171 | <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> |
2172 | <dt>Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)</dt> |
1966 | <dt>Activating one watcher: O(1)</dt> |
2173 | <dt>Activating one watcher: O(1)</dt> |
1967 | </dl> |
2174 | </dl> |
1968 | </p> |
2175 | </p> |
… | |
… | |
1970 | |
2177 | |
1971 | |
2178 | |
1972 | |
2179 | |
1973 | |
2180 | |
1974 | </div> |
2181 | </div> |
1975 | <h1 id="AUTHOR">AUTHOR</h1><p><a href="#TOP" class="toplink">Top</a></p> |
2182 | <h1 id="AUTHOR">AUTHOR</h1> |
1976 | <div id="AUTHOR_CONTENT"> |
2183 | <div id="AUTHOR_CONTENT"> |
1977 | <p>Marc Lehmann <libev@schmorp.de>.</p> |
2184 | <p>Marc Lehmann <libev@schmorp.de>.</p> |
1978 | |
2185 | |
1979 | </div> |
2186 | </div> |
1980 | </div></body> |
2187 | </div></body> |