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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="&lt;standard input&gt;" /> 7 <meta name="inputfile" content="&lt;standard input&gt;" />
8 <meta name="outputfile" content="&lt;standard output&gt;" /> 8 <meta name="outputfile" content="&lt;standard output&gt;" />
9 <meta name="created" content="Thu Nov 22 13:26:17 2007" /> 9 <meta name="created" content="Sat Nov 24 05:58:35 2007" />
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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 -->
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32<li><a href="#code_ev_periodic_code_to_cron_or_not"><code>ev_periodic</code> - to cron or not to cron</a></li> 32<li><a href="#code_ev_periodic_code_to_cron_or_not"><code>ev_periodic</code> - to cron or not to cron</a></li>
33<li><a href="#code_ev_signal_code_signal_me_when_a"><code>ev_signal</code> - signal me when a signal gets signalled</a></li> 33<li><a href="#code_ev_signal_code_signal_me_when_a"><code>ev_signal</code> - signal me when a signal gets signalled</a></li>
34<li><a href="#code_ev_child_code_wait_for_pid_stat"><code>ev_child</code> - wait for pid status changes</a></li> 34<li><a href="#code_ev_child_code_wait_for_pid_stat"><code>ev_child</code> - wait for pid status changes</a></li>
35<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> 35<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>
36<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> 36<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>
37<li><a href="#code_ev_embed_code_when_one_backend_"><code>ev_embed</code> - when one backend isn't enough</a></li>
37</ul> 38</ul>
38</li> 39</li>
39<li><a href="#OTHER_FUNCTIONS">OTHER FUNCTIONS</a></li> 40<li><a href="#OTHER_FUNCTIONS">OTHER FUNCTIONS</a></li>
40<li><a href="#LIBEVENT_EMULATION">LIBEVENT EMULATION</a></li> 41<li><a href="#LIBEVENT_EMULATION">LIBEVENT EMULATION</a></li>
41<li><a href="#C_SUPPORT">C++ SUPPORT</a></li> 42<li><a href="#C_SUPPORT">C++ SUPPORT</a></li>
… …
96<div id="TIME_REPRESENTATION_CONTENT"> 97<div id="TIME_REPRESENTATION_CONTENT">
97<p>Libev represents time as a single floating point number, representing the 98<p>Libev represents time as a single floating point number, representing the
98(fractional) number of seconds since the (POSIX) epoch (somewhere near 99(fractional) number of seconds since the (POSIX) epoch (somewhere near
99the beginning of 1970, details are complicated, don't ask). This type is 100the beginning of 1970, details are complicated, don't ask). This type is
100called <code>ev_tstamp</code>, which is what you should use too. It usually aliases 101called <code>ev_tstamp</code>, which is what you should use too. It usually aliases
101to the double type in C.</p> 102to the <code>double</code> type in C, and when you need to do any calculations on
103it, you should treat it as such.</p>
104
105
106
107
102 108
103</div> 109</div>
104<h1 id="GLOBAL_FUNCTIONS">GLOBAL FUNCTIONS</h1><p><a href="#TOP" class="toplink">Top</a></p> 110<h1 id="GLOBAL_FUNCTIONS">GLOBAL FUNCTIONS</h1><p><a href="#TOP" class="toplink">Top</a></p>
105<div id="GLOBAL_FUNCTIONS_CONTENT"> 111<div id="GLOBAL_FUNCTIONS_CONTENT">
106<p>These functions can be called anytime, even before initialising the 112<p>These functions can be called anytime, even before initialising the
… …
122version of the library your program was compiled against.</p> 128version of the library your program was compiled against.</p>
123 <p>Usually, it's a good idea to terminate if the major versions mismatch, 129 <p>Usually, it's a good idea to terminate if the major versions mismatch,
124as this indicates an incompatible change. Minor versions are usually 130as this indicates an incompatible change. Minor versions are usually
125compatible to older versions, so a larger minor version alone is usually 131compatible to older versions, so a larger minor version alone is usually
126not a problem.</p> 132not a problem.</p>
133 <p>Example: make sure we haven't accidentally been linked against the wrong
134version:</p>
135<pre> assert ((&quot;libev version mismatch&quot;,
136 ev_version_major () == EV_VERSION_MAJOR
137 &amp;&amp; ev_version_minor () &gt;= EV_VERSION_MINOR));
138
139</pre>
140 </dd>
141 <dt>unsigned int ev_supported_backends ()</dt>
142 <dd>
143 <p>Return the set of all backends (i.e. their corresponding <code>EV_BACKEND_*</code>
144value) compiled into this binary of libev (independent of their
145availability on the system you are running on). See <code>ev_default_loop</code> for
146a description of the set values.</p>
147 <p>Example: make sure we have the epoll method, because yeah this is cool and
148a must have and can we have a torrent of it please!!!11</p>
149<pre> assert ((&quot;sorry, no epoll, no sex&quot;,
150 ev_supported_backends () &amp; EVBACKEND_EPOLL));
151
152</pre>
153 </dd>
154 <dt>unsigned int ev_recommended_backends ()</dt>
155 <dd>
156 <p>Return the set of all backends compiled into this binary of libev and also
157recommended for this platform. This set is often smaller than the one
158returned by <code>ev_supported_backends</code>, as for example kqueue is broken on
159most BSDs and will not be autodetected unless you explicitly request it
160(assuming you know what you are doing). This is the set of backends that
161libev will probe for if you specify no backends explicitly.</p>
162 </dd>
163 <dt>unsigned int ev_embeddable_backends ()</dt>
164 <dd>
165 <p>Returns the set of backends that are embeddable in other event loops. This
166is the theoretical, all-platform, value. To find which backends
167might be supported on the current system, you would need to look at
168<code>ev_embeddable_backends () &amp; ev_supported_backends ()</code>, likewise for
169recommended ones.</p>
170 <p>See the description of <code>ev_embed</code> watchers for more info.</p>
127 </dd> 171 </dd>
128 <dt>ev_set_allocator (void *(*cb)(void *ptr, long size))</dt> 172 <dt>ev_set_allocator (void *(*cb)(void *ptr, long size))</dt>
129 <dd> 173 <dd>
130 <p>Sets the allocation function to use (the prototype is similar to the 174 <p>Sets the allocation function to use (the prototype is similar to the
131realloc C function, the semantics are identical). It is used to allocate 175realloc C function, the semantics are identical). It is used to allocate
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133needs to be allocated, the library might abort or take some potentially 177needs to be allocated, the library might abort or take some potentially
134destructive action. The default is your system realloc function.</p> 178destructive action. The default is your system realloc function.</p>
135 <p>You could override this function in high-availability programs to, say, 179 <p>You could override this function in high-availability programs to, say,
136free some memory if it cannot allocate memory, to use a special allocator, 180free some memory if it cannot allocate memory, to use a special allocator,
137or even to sleep a while and retry until some memory is available.</p> 181or even to sleep a while and retry until some memory is available.</p>
182 <p>Example: replace the libev allocator with one that waits a bit and then
183retries: better than mine).</p>
184<pre> static void *
185 persistent_realloc (void *ptr, long size)
186 {
187 for (;;)
188 {
189 void *newptr = realloc (ptr, size);
190
191 if (newptr)
192 return newptr;
193
194 sleep (60);
195 }
196 }
197
198 ...
199 ev_set_allocator (persistent_realloc);
200
201</pre>
138 </dd> 202 </dd>
139 <dt>ev_set_syserr_cb (void (*cb)(const char *msg));</dt> 203 <dt>ev_set_syserr_cb (void (*cb)(const char *msg));</dt>
140 <dd> 204 <dd>
141 <p>Set the callback function to call on a retryable syscall error (such 205 <p>Set the callback function to call on a retryable syscall error (such
142as failed select, poll, epoll_wait). The message is a printable string 206as failed select, poll, epoll_wait). The message is a printable string
143indicating the system call or subsystem causing the problem. If this 207indicating the system call or subsystem causing the problem. If this
144callback is set, then libev will expect it to remedy the sitution, no 208callback is set, then libev will expect it to remedy the sitution, no
145matter what, when it returns. That is, libev will generally retry the 209matter what, when it returns. That is, libev will generally retry the
146requested operation, or, if the condition doesn't go away, do bad stuff 210requested operation, or, if the condition doesn't go away, do bad stuff
147(such as abort).</p> 211(such as abort).</p>
212 <p>Example: do the same thing as libev does internally:</p>
213<pre> static void
214 fatal_error (const char *msg)
215 {
216 perror (msg);
217 abort ();
218 }
219
220 ...
221 ev_set_syserr_cb (fatal_error);
222
223</pre>
148 </dd> 224 </dd>
149</dl> 225</dl>
150 226
151</div> 227</div>
152<h1 id="FUNCTIONS_CONTROLLING_THE_EVENT_LOOP">FUNCTIONS CONTROLLING THE EVENT LOOP</h1><p><a href="#TOP" class="toplink">Top</a></p> 228<h1 id="FUNCTIONS_CONTROLLING_THE_EVENT_LOOP">FUNCTIONS CONTROLLING THE EVENT LOOP</h1><p><a href="#TOP" class="toplink">Top</a></p>
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164 <dt>struct ev_loop *ev_default_loop (unsigned int flags)</dt> 240 <dt>struct ev_loop *ev_default_loop (unsigned int flags)</dt>
165 <dd> 241 <dd>
166 <p>This will initialise the default event loop if it hasn't been initialised 242 <p>This will initialise the default event loop if it hasn't been initialised
167yet and return it. If the default loop could not be initialised, returns 243yet and return it. If the default loop could not be initialised, returns
168false. If it already was initialised it simply returns it (and ignores the 244false. If it already was initialised it simply returns it (and ignores the
169flags).</p> 245flags. If that is troubling you, check <code>ev_backend ()</code> afterwards).</p>
170 <p>If you don't know what event loop to use, use the one returned from this 246 <p>If you don't know what event loop to use, use the one returned from this
171function.</p> 247function.</p>
172 <p>The flags argument can be used to specify special behaviour or specific 248 <p>The flags argument can be used to specify special behaviour or specific
173backends to use, and is usually specified as 0 (or EVFLAG_AUTO).</p> 249backends to use, and is usually specified as <code>0</code> (or <code>EVFLAG_AUTO</code>).</p>
174 <p>It supports the following flags:</p> 250 <p>The following flags are supported:</p>
175 <p> 251 <p>
176 <dl> 252 <dl>
177 <dt><code>EVFLAG_AUTO</code></dt> 253 <dt><code>EVFLAG_AUTO</code></dt>
178 <dd> 254 <dd>
179 <p>The default flags value. Use this if you have no clue (it's the right 255 <p>The default flags value. Use this if you have no clue (it's the right
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186<code>LIBEV_FLAGS</code>. Otherwise (the default), this environment variable will 262<code>LIBEV_FLAGS</code>. Otherwise (the default), this environment variable will
187override the flags completely if it is found in the environment. This is 263override the flags completely if it is found in the environment. This is
188useful to try out specific backends to test their performance, or to work 264useful to try out specific backends to test their performance, or to work
189around bugs.</p> 265around bugs.</p>
190 </dd> 266 </dd>
191 <dt><code>EVMETHOD_SELECT</code> (value 1, portable select backend)</dt> 267 <dt><code>EVBACKEND_SELECT</code> (value 1, portable select backend)</dt>
192 <dd> 268 <dd>
193 <p>This is your standard select(2) backend. Not <i>completely</i> standard, as 269 <p>This is your standard select(2) backend. Not <i>completely</i> standard, as
194libev tries to roll its own fd_set with no limits on the number of fds, 270libev tries to roll its own fd_set with no limits on the number of fds,
195but if that fails, expect a fairly low limit on the number of fds when 271but if that fails, expect a fairly low limit on the number of fds when
196using this backend. It doesn't scale too well (O(highest_fd)), but its usually 272using this backend. It doesn't scale too well (O(highest_fd)), but its usually
197the fastest backend for a low number of fds.</p> 273the fastest backend for a low number of fds.</p>
198 </dd> 274 </dd>
199 <dt><code>EVMETHOD_POLL</code> (value 2, poll backend, available everywhere except on windows)</dt> 275 <dt><code>EVBACKEND_POLL</code> (value 2, poll backend, available everywhere except on windows)</dt>
200 <dd> 276 <dd>
201 <p>And this is your standard poll(2) backend. It's more complicated than 277 <p>And this is your standard poll(2) backend. It's more complicated than
202select, but handles sparse fds better and has no artificial limit on the 278select, but handles sparse fds better and has no artificial limit on the
203number of fds you can use (except it will slow down considerably with a 279number of fds you can use (except it will slow down considerably with a
204lot of inactive fds). It scales similarly to select, i.e. O(total_fds).</p> 280lot of inactive fds). It scales similarly to select, i.e. O(total_fds).</p>
205 </dd> 281 </dd>
206 <dt><code>EVMETHOD_EPOLL</code> (value 4, Linux)</dt> 282 <dt><code>EVBACKEND_EPOLL</code> (value 4, Linux)</dt>
207 <dd> 283 <dd>
208 <p>For few fds, this backend is a bit little slower than poll and select, 284 <p>For few fds, this backend is a bit little slower than poll and select,
209but it scales phenomenally better. While poll and select usually scale like 285but it scales phenomenally better. While poll and select usually scale like
210O(total_fds) where n is the total number of fds (or the highest fd), epoll scales 286O(total_fds) where n is the total number of fds (or the highest fd), epoll scales
211either O(1) or O(active_fds).</p> 287either O(1) or O(active_fds).</p>
212 <p>While stopping and starting an I/O watcher in the same iteration will 288 <p>While stopping and starting an I/O watcher in the same iteration will
213result in some caching, there is still a syscall per such incident 289result in some caching, there is still a syscall per such incident
214(because the fd could point to a different file description now), so its 290(because the fd could point to a different file description now), so its
215best to avoid that. Also, dup()ed file descriptors might not work very 291best to avoid that. Also, dup()ed file descriptors might not work very
216well if you register events for both fds.</p> 292well if you register events for both fds.</p>
293 <p>Please note that epoll sometimes generates spurious notifications, so you
294need to use non-blocking I/O or other means to avoid blocking when no data
295(or space) is available.</p>
217 </dd> 296 </dd>
218 <dt><code>EVMETHOD_KQUEUE</code> (value 8, most BSD clones)</dt> 297 <dt><code>EVBACKEND_KQUEUE</code> (value 8, most BSD clones)</dt>
219 <dd> 298 <dd>
220 <p>Kqueue deserves special mention, as at the time of this writing, it 299 <p>Kqueue deserves special mention, as at the time of this writing, it
221was broken on all BSDs except NetBSD (usually it doesn't work with 300was broken on all BSDs except NetBSD (usually it doesn't work with
222anything but sockets and pipes, except on Darwin, where of course its 301anything but sockets and pipes, except on Darwin, where of course its
223completely useless). For this reason its not being &quot;autodetected&quot; unless 302completely useless). For this reason its not being &quot;autodetected&quot;
224you explicitly specify the flags (i.e. you don't use EVFLAG_AUTO).</p> 303unless you explicitly specify it explicitly in the flags (i.e. using
304<code>EVBACKEND_KQUEUE</code>).</p>
225 <p>It scales in the same way as the epoll backend, but the interface to the 305 <p>It scales in the same way as the epoll backend, but the interface to the
226kernel is more efficient (which says nothing about its actual speed, of 306kernel is more efficient (which says nothing about its actual speed, of
227course). While starting and stopping an I/O watcher does not cause an 307course). While starting and stopping an I/O watcher does not cause an
228extra syscall as with epoll, it still adds up to four event changes per 308extra syscall as with epoll, it still adds up to four event changes per
229incident, so its best to avoid that.</p> 309incident, so its best to avoid that.</p>
230 </dd> 310 </dd>
231 <dt><code>EVMETHOD_DEVPOLL</code> (value 16, Solaris 8)</dt> 311 <dt><code>EVBACKEND_DEVPOLL</code> (value 16, Solaris 8)</dt>
232 <dd> 312 <dd>
233 <p>This is not implemented yet (and might never be).</p> 313 <p>This is not implemented yet (and might never be).</p>
234 </dd> 314 </dd>
235 <dt><code>EVMETHOD_PORT</code> (value 32, Solaris 10)</dt> 315 <dt><code>EVBACKEND_PORT</code> (value 32, Solaris 10)</dt>
236 <dd> 316 <dd>
237 <p>This uses the Solaris 10 port mechanism. As with everything on Solaris, 317 <p>This uses the Solaris 10 port mechanism. As with everything on Solaris,
238it's really slow, but it still scales very well (O(active_fds)).</p> 318it's really slow, but it still scales very well (O(active_fds)).</p>
319 <p>Please note that solaris ports can result in a lot of spurious
320notifications, so you need to use non-blocking I/O or other means to avoid
321blocking when no data (or space) is available.</p>
239 </dd> 322 </dd>
240 <dt><code>EVMETHOD_ALL</code></dt> 323 <dt><code>EVBACKEND_ALL</code></dt>
241 <dd> 324 <dd>
242 <p>Try all backends (even potentially broken ones). Since this is a mask, you 325 <p>Try all backends (even potentially broken ones that wouldn't be tried
243can do stuff like <code>EVMETHOD_ALL &amp; ~EVMETHOD_KQUEUE</code>.</p> 326with <code>EVFLAG_AUTO</code>). Since this is a mask, you can do stuff such as
327<code>EVBACKEND_ALL &amp; ~EVBACKEND_KQUEUE</code>.</p>
244 </dd> 328 </dd>
245 </dl> 329 </dl>
246 </p> 330 </p>
247 <p>If one or more of these are ored into the flags value, then only these 331 <p>If one or more of these are ored into the flags value, then only these
248backends will be tried (in the reverse order as given here). If none are 332backends will be tried (in the reverse order as given here). If none are
249specified, most compiled-in backend will be tried, usually in reverse 333specified, most compiled-in backend will be tried, usually in reverse
250order of their flag values :)</p> 334order of their flag values :)</p>
335 <p>The most typical usage is like this:</p>
336<pre> if (!ev_default_loop (0))
337 fatal (&quot;could not initialise libev, bad $LIBEV_FLAGS in environment?&quot;);
338
339</pre>
340 <p>Restrict libev to the select and poll backends, and do not allow
341environment settings to be taken into account:</p>
342<pre> ev_default_loop (EVBACKEND_POLL | EVBACKEND_SELECT | EVFLAG_NOENV);
343
344</pre>
345 <p>Use whatever libev has to offer, but make sure that kqueue is used if
346available (warning, breaks stuff, best use only with your own private
347event loop and only if you know the OS supports your types of fds):</p>
348<pre> ev_default_loop (ev_recommended_backends () | EVBACKEND_KQUEUE);
349
350</pre>
251 </dd> 351 </dd>
252 <dt>struct ev_loop *ev_loop_new (unsigned int flags)</dt> 352 <dt>struct ev_loop *ev_loop_new (unsigned int flags)</dt>
253 <dd> 353 <dd>
254 <p>Similar to <code>ev_default_loop</code>, but always creates a new event loop that is 354 <p>Similar to <code>ev_default_loop</code>, but always creates a new event loop that is
255always distinct from the default loop. Unlike the default loop, it cannot 355always distinct from the default loop. Unlike the default loop, it cannot
256handle signal and child watchers, and attempts to do so will be greeted by 356handle signal and child watchers, and attempts to do so will be greeted by
257undefined behaviour (or a failed assertion if assertions are enabled).</p> 357undefined behaviour (or a failed assertion if assertions are enabled).</p>
358 <p>Example: try to create a event loop that uses epoll and nothing else.</p>
359<pre> struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV);
360 if (!epoller)
361 fatal (&quot;no epoll found here, maybe it hides under your chair&quot;);
362
363</pre>
258 </dd> 364 </dd>
259 <dt>ev_default_destroy ()</dt> 365 <dt>ev_default_destroy ()</dt>
260 <dd> 366 <dd>
261 <p>Destroys the default loop again (frees all memory and kernel state 367 <p>Destroys the default loop again (frees all memory and kernel state
262etc.). This stops all registered event watchers (by not touching them in 368etc.). This stops all registered event watchers (by not touching them in
… …
271 <dd> 377 <dd>
272 <p>This function reinitialises the kernel state for backends that have 378 <p>This function reinitialises the kernel state for backends that have
273one. Despite the name, you can call it anytime, but it makes most sense 379one. Despite the name, you can call it anytime, but it makes most sense
274after forking, in either the parent or child process (or both, but that 380after forking, in either the parent or child process (or both, but that
275again makes little sense).</p> 381again makes little sense).</p>
276 <p>You <i>must</i> call this function after forking if and only if you want to 382 <p>You <i>must</i> call this function in the child process after forking if and
277use the event library in both processes. If you just fork+exec, you don't 383only if you want to use the event library in both processes. If you just
278have to call it.</p> 384fork+exec, you don't have to call it.</p>
279 <p>The function itself is quite fast and it's usually not a problem to call 385 <p>The function itself is quite fast and it's usually not a problem to call
280it just in case after a fork. To make this easy, the function will fit in 386it just in case after a fork. To make this easy, the function will fit in
281quite nicely into a call to <code>pthread_atfork</code>:</p> 387quite nicely into a call to <code>pthread_atfork</code>:</p>
282<pre> pthread_atfork (0, 0, ev_default_fork); 388<pre> pthread_atfork (0, 0, ev_default_fork);
283 389
284</pre> 390</pre>
391 <p>At the moment, <code>EVBACKEND_SELECT</code> and <code>EVBACKEND_POLL</code> are safe to use
392without calling this function, so if you force one of those backends you
393do not need to care.</p>
285 </dd> 394 </dd>
286 <dt>ev_loop_fork (loop)</dt> 395 <dt>ev_loop_fork (loop)</dt>
287 <dd> 396 <dd>
288 <p>Like <code>ev_default_fork</code>, but acts on an event loop created by 397 <p>Like <code>ev_default_fork</code>, but acts on an event loop created by
289<code>ev_loop_new</code>. Yes, you have to call this on every allocated event loop 398<code>ev_loop_new</code>. Yes, you have to call this on every allocated event loop
290after fork, and how you do this is entirely your own problem.</p> 399after fork, and how you do this is entirely your own problem.</p>
291 </dd> 400 </dd>
292 <dt>unsigned int ev_method (loop)</dt> 401 <dt>unsigned int ev_backend (loop)</dt>
293 <dd> 402 <dd>
294 <p>Returns one of the <code>EVMETHOD_*</code> flags indicating the event backend in 403 <p>Returns one of the <code>EVBACKEND_*</code> flags indicating the event backend in
295use.</p> 404use.</p>
296 </dd> 405 </dd>
297 <dt>ev_tstamp ev_now (loop)</dt> 406 <dt>ev_tstamp ev_now (loop)</dt>
298 <dd> 407 <dd>
299 <p>Returns the current &quot;event loop time&quot;, which is the time the event loop 408 <p>Returns the current &quot;event loop time&quot;, which is the time the event loop
300got events and started processing them. This timestamp does not change 409received events and started processing them. This timestamp does not
301as long as callbacks are being processed, and this is also the base time 410change as long as callbacks are being processed, and this is also the base
302used for relative timers. You can treat it as the timestamp of the event 411time used for relative timers. You can treat it as the timestamp of the
303occuring (or more correctly, the mainloop finding out about it).</p> 412event occuring (or more correctly, libev finding out about it).</p>
304 </dd> 413 </dd>
305 <dt>ev_loop (loop, int flags)</dt> 414 <dt>ev_loop (loop, int flags)</dt>
306 <dd> 415 <dd>
307 <p>Finally, this is it, the event handler. This function usually is called 416 <p>Finally, this is it, the event handler. This function usually is called
308after you initialised all your watchers and you want to start handling 417after you initialised all your watchers and you want to start handling
309events.</p> 418events.</p>
310 <p>If the flags argument is specified as 0, it will not return until either 419 <p>If the flags argument is specified as <code>0</code>, it will not return until
311no event watchers are active anymore or <code>ev_unloop</code> was called.</p> 420either no event watchers are active anymore or <code>ev_unloop</code> was called.</p>
421 <p>Please note that an explicit <code>ev_unloop</code> is usually better than
422relying on all watchers to be stopped when deciding when a program has
423finished (especially in interactive programs), but having a program that
424automatically loops as long as it has to and no longer by virtue of
425relying on its watchers stopping correctly is a thing of beauty.</p>
312 <p>A flags value of <code>EVLOOP_NONBLOCK</code> will look for new events, will handle 426 <p>A flags value of <code>EVLOOP_NONBLOCK</code> will look for new events, will handle
313those events and any outstanding ones, but will not block your process in 427those events and any outstanding ones, but will not block your process in
314case there are no events and will return after one iteration of the loop.</p> 428case there are no events and will return after one iteration of the loop.</p>
315 <p>A flags value of <code>EVLOOP_ONESHOT</code> will look for new events (waiting if 429 <p>A flags value of <code>EVLOOP_ONESHOT</code> will look for new events (waiting if
316neccessary) and will handle those and any outstanding ones. It will block 430neccessary) and will handle those and any outstanding ones. It will block
317your process until at least one new event arrives, and will return after 431your process until at least one new event arrives, and will return after
318one iteration of the loop.</p> 432one iteration of the loop. This is useful if you are waiting for some
319 <p>This flags value could be used to implement alternative looping 433external event in conjunction with something not expressible using other
320constructs, but the <code>prepare</code> and <code>check</code> watchers provide a better and 434libev watchers. However, a pair of <code>ev_prepare</code>/<code>ev_check</code> watchers is
321more generic mechanism.</p> 435usually a better approach for this kind of thing.</p>
322 <p>Here are the gory details of what ev_loop does:</p> 436 <p>Here are the gory details of what <code>ev_loop</code> does:</p>
323<pre> 1. If there are no active watchers (reference count is zero), return. 437<pre> * If there are no active watchers (reference count is zero), return.
324 2. Queue and immediately call all prepare watchers. 438 - Queue prepare watchers and then call all outstanding watchers.
325 3. If we have been forked, recreate the kernel state. 439 - If we have been forked, recreate the kernel state.
326 4. Update the kernel state with all outstanding changes. 440 - Update the kernel state with all outstanding changes.
327 5. Update the &quot;event loop time&quot;. 441 - Update the &quot;event loop time&quot;.
328 6. Calculate for how long to block. 442 - Calculate for how long to block.
329 7. Block the process, waiting for events. 443 - Block the process, waiting for any events.
444 - Queue all outstanding I/O (fd) events.
330 8. Update the &quot;event loop time&quot; and do time jump handling. 445 - Update the &quot;event loop time&quot; and do time jump handling.
331 9. Queue all outstanding timers. 446 - Queue all outstanding timers.
332 10. Queue all outstanding periodics. 447 - Queue all outstanding periodics.
333 11. If no events are pending now, queue all idle watchers. 448 - If no events are pending now, queue all idle watchers.
334 12. Queue all check watchers. 449 - Queue all check watchers.
335 13. Call all queued watchers in reverse order (i.e. check watchers first). 450 - Call all queued watchers in reverse order (i.e. check watchers first).
451 Signals and child watchers are implemented as I/O watchers, and will
452 be handled here by queueing them when their watcher gets executed.
336 14. If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK 453 - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK
337 was used, return, otherwise continue with step #1. 454 were used, return, otherwise continue with step *.
455
456</pre>
457 <p>Example: queue some jobs and then loop until no events are outsanding
458anymore.</p>
459<pre> ... queue jobs here, make sure they register event watchers as long
460 ... as they still have work to do (even an idle watcher will do..)
461 ev_loop (my_loop, 0);
462 ... jobs done. yeah!
338 463
339</pre> 464</pre>
340 </dd> 465 </dd>
341 <dt>ev_unloop (loop, how)</dt> 466 <dt>ev_unloop (loop, how)</dt>
342 <dd> 467 <dd>
… …
356example, libev itself uses this for its internal signal pipe: It is not 481example, libev itself uses this for its internal signal pipe: It is not
357visible to the libev user and should not keep <code>ev_loop</code> from exiting if 482visible to the libev user and should not keep <code>ev_loop</code> from exiting if
358no event watchers registered by it are active. It is also an excellent 483no event watchers registered by it are active. It is also an excellent
359way to do this for generic recurring timers or from within third-party 484way to do this for generic recurring timers or from within third-party
360libraries. Just remember to <i>unref after start</i> and <i>ref before stop</i>.</p> 485libraries. Just remember to <i>unref after start</i> and <i>ref before stop</i>.</p>
486 <p>Example: create a signal watcher, but keep it from keeping <code>ev_loop</code>
487running when nothing else is active.</p>
488<pre> struct dv_signal exitsig;
489 ev_signal_init (&amp;exitsig, sig_cb, SIGINT);
490 ev_signal_start (myloop, &amp;exitsig);
491 evf_unref (myloop);
492
493</pre>
494 <p>Example: for some weird reason, unregister the above signal handler again.</p>
495<pre> ev_ref (myloop);
496 ev_signal_stop (myloop, &amp;exitsig);
497
498</pre>
361 </dd> 499 </dd>
362</dl> 500</dl>
363 501
364</div> 502</div>
365<h1 id="ANATOMY_OF_A_WATCHER">ANATOMY OF A WATCHER</h1><p><a href="#TOP" class="toplink">Top</a></p> 503<h1 id="ANATOMY_OF_A_WATCHER">ANATOMY OF A WATCHER</h1><p><a href="#TOP" class="toplink">Top</a></p>
… …
397with a watcher-specific start function (<code>ev_&lt;type&gt;_start (loop, watcher 535with a watcher-specific start function (<code>ev_&lt;type&gt;_start (loop, watcher
398*)</code>), and you can stop watching for events at any time by calling the 536*)</code>), and you can stop watching for events at any time by calling the
399corresponding stop function (<code>ev_&lt;type&gt;_stop (loop, watcher *)</code>.</p> 537corresponding stop function (<code>ev_&lt;type&gt;_stop (loop, watcher *)</code>.</p>
400<p>As long as your watcher is active (has been started but not stopped) you 538<p>As long as your watcher is active (has been started but not stopped) you
401must not touch the values stored in it. Most specifically you must never 539must not touch the values stored in it. Most specifically you must never
402reinitialise it or call its set method.</p> 540reinitialise it or call its set macro.</p>
403<p>You can check whether an event is active by calling the <code>ev_is_active 541<p>You can check whether an event is active by calling the <code>ev_is_active
404(watcher *)</code> macro. To see whether an event is outstanding (but the 542(watcher *)</code> macro. To see whether an event is outstanding (but the
405callback for it has not been called yet) you can use the <code>ev_is_pending 543callback for it has not been called yet) you can use the <code>ev_is_pending
406(watcher *)</code> macro.</p> 544(watcher *)</code> macro.</p>
407<p>Each and every callback receives the event loop pointer as first, the 545<p>Each and every callback receives the event loop pointer as first, the
… …
500</div> 638</div>
501<h1 id="WATCHER_TYPES">WATCHER TYPES</h1><p><a href="#TOP" class="toplink">Top</a></p> 639<h1 id="WATCHER_TYPES">WATCHER TYPES</h1><p><a href="#TOP" class="toplink">Top</a></p>
502<div id="WATCHER_TYPES_CONTENT"> 640<div id="WATCHER_TYPES_CONTENT">
503<p>This section describes each watcher in detail, but will not repeat 641<p>This section describes each watcher in detail, but will not repeat
504information given in the last section.</p> 642information given in the last section.</p>
643
644
645
646
505 647
506</div> 648</div>
507<h2 id="code_ev_io_code_is_this_file_descrip"><code>ev_io</code> - is this file descriptor readable or writable</h2> 649<h2 id="code_ev_io_code_is_this_file_descrip"><code>ev_io</code> - is this file descriptor readable or writable</h2>
508<div id="code_ev_io_code_is_this_file_descrip-2"> 650<div id="code_ev_io_code_is_this_file_descrip-2">
509<p>I/O watchers check whether a file descriptor is readable or writable 651<p>I/O watchers check whether a file descriptor is readable or writable
… …
519(the linux epoll backend is a notable example) cannot handle dup'ed file 661(the linux epoll backend is a notable example) cannot handle dup'ed file
520descriptors correctly if you register interest in two or more fds pointing 662descriptors correctly if you register interest in two or more fds pointing
521to the same underlying file/socket etc. description (that is, they share 663to the same underlying file/socket etc. description (that is, they share
522the same underlying &quot;file open&quot;).</p> 664the same underlying &quot;file open&quot;).</p>
523<p>If you must do this, then force the use of a known-to-be-good backend 665<p>If you must do this, then force the use of a known-to-be-good backend
524(at the time of this writing, this includes only EVMETHOD_SELECT and 666(at the time of this writing, this includes only <code>EVBACKEND_SELECT</code> and
525EVMETHOD_POLL).</p> 667<code>EVBACKEND_POLL</code>).</p>
526<dl> 668<dl>
527 <dt>ev_io_init (ev_io *, callback, int fd, int events)</dt> 669 <dt>ev_io_init (ev_io *, callback, int fd, int events)</dt>
528 <dt>ev_io_set (ev_io *, int fd, int events)</dt> 670 <dt>ev_io_set (ev_io *, int fd, int events)</dt>
529 <dd> 671 <dd>
530 <p>Configures an <code>ev_io</code> watcher. The fd is the file descriptor to rceeive 672 <p>Configures an <code>ev_io</code> watcher. The fd is the file descriptor to rceeive
531events for and events is either <code>EV_READ</code>, <code>EV_WRITE</code> or <code>EV_READ | 673events for and events is either <code>EV_READ</code>, <code>EV_WRITE</code> or <code>EV_READ |
532EV_WRITE</code> to receive the given events.</p> 674EV_WRITE</code> to receive the given events.</p>
675 <p>Please note that most of the more scalable backend mechanisms (for example
676epoll and solaris ports) can result in spurious readyness notifications
677for file descriptors, so you practically need to use non-blocking I/O (and
678treat callback invocation as hint only), or retest separately with a safe
679interface before doing I/O (XLib can do this), or force the use of either
680<code>EVBACKEND_SELECT</code> or <code>EVBACKEND_POLL</code>, which don't suffer from this
681problem. Also note that it is quite easy to have your callback invoked
682when the readyness condition is no longer valid even when employing
683typical ways of handling events, so its a good idea to use non-blocking
684I/O unconditionally.</p>
533 </dd> 685 </dd>
534</dl> 686</dl>
687<p>Example: call <code>stdin_readable_cb</code> when STDIN_FILENO has become, well
688readable, but only once. Since it is likely line-buffered, you could
689attempt to read a whole line in the callback:</p>
690<pre> static void
691 stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents)
692 {
693 ev_io_stop (loop, w);
694 .. read from stdin here (or from w-&gt;fd) and haqndle any I/O errors
695 }
696
697 ...
698 struct ev_loop *loop = ev_default_init (0);
699 struct ev_io stdin_readable;
700 ev_io_init (&amp;stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);
701 ev_io_start (loop, &amp;stdin_readable);
702 ev_loop (loop, 0);
703
704
705
706
707</pre>
535 708
536</div> 709</div>
537<h2 id="code_ev_timer_code_relative_and_opti"><code>ev_timer</code> - relative and optionally recurring timeouts</h2> 710<h2 id="code_ev_timer_code_relative_and_opti"><code>ev_timer</code> - relative and optionally recurring timeouts</h2>
538<div id="code_ev_timer_code_relative_and_opti-2"> 711<div id="code_ev_timer_code_relative_and_opti-2">
539<p>Timer watchers are simple relative timers that generate an event after a 712<p>Timer watchers are simple relative timers that generate an event after a
… …
583time you successfully read or write some data. If you go into an idle 756time you successfully read or write some data. If you go into an idle
584state where you do not expect data to travel on the socket, you can stop 757state where you do not expect data to travel on the socket, you can stop
585the timer, and again will automatically restart it if need be.</p> 758the timer, and again will automatically restart it if need be.</p>
586 </dd> 759 </dd>
587</dl> 760</dl>
761<p>Example: create a timer that fires after 60 seconds.</p>
762<pre> static void
763 one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents)
764 {
765 .. one minute over, w is actually stopped right here
766 }
767
768 struct ev_timer mytimer;
769 ev_timer_init (&amp;mytimer, one_minute_cb, 60., 0.);
770 ev_timer_start (loop, &amp;mytimer);
771
772</pre>
773<p>Example: create a timeout timer that times out after 10 seconds of
774inactivity.</p>
775<pre> static void
776 timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents)
777 {
778 .. ten seconds without any activity
779 }
780
781 struct ev_timer mytimer;
782 ev_timer_init (&amp;mytimer, timeout_cb, 0., 10.); /* note, only repeat used */
783 ev_timer_again (&amp;mytimer); /* start timer */
784 ev_loop (loop, 0);
785
786 // and in some piece of code that gets executed on any &quot;activity&quot;:
787 // reset the timeout to start ticking again at 10 seconds
788 ev_timer_again (&amp;mytimer);
789
790
791
792
793</pre>
588 794
589</div> 795</div>
590<h2 id="code_ev_periodic_code_to_cron_or_not"><code>ev_periodic</code> - to cron or not to cron</h2> 796<h2 id="code_ev_periodic_code_to_cron_or_not"><code>ev_periodic</code> - to cron or not to cron</h2>
591<div id="code_ev_periodic_code_to_cron_or_not-2"> 797<div id="code_ev_periodic_code_to_cron_or_not-2">
592<p>Periodic watchers are also timers of a kind, but they are very versatile 798<p>Periodic watchers are also timers of a kind, but they are very versatile
… …
676when you changed some parameters or the reschedule callback would return 882when you changed some parameters or the reschedule callback would return
677a different time than the last time it was called (e.g. in a crond like 883a different time than the last time it was called (e.g. in a crond like
678program when the crontabs have changed).</p> 884program when the crontabs have changed).</p>
679 </dd> 885 </dd>
680</dl> 886</dl>
887<p>Example: call a callback every hour, or, more precisely, whenever the
888system clock is divisible by 3600. The callback invocation times have
889potentially a lot of jittering, but good long-term stability.</p>
890<pre> static void
891 clock_cb (struct ev_loop *loop, struct ev_io *w, int revents)
892 {
893 ... its now a full hour (UTC, or TAI or whatever your clock follows)
894 }
895
896 struct ev_periodic hourly_tick;
897 ev_periodic_init (&amp;hourly_tick, clock_cb, 0., 3600., 0);
898 ev_periodic_start (loop, &amp;hourly_tick);
899
900</pre>
901<p>Example: the same as above, but use a reschedule callback to do it:</p>
902<pre> #include &lt;math.h&gt;
903
904 static ev_tstamp
905 my_scheduler_cb (struct ev_periodic *w, ev_tstamp now)
906 {
907 return fmod (now, 3600.) + 3600.;
908 }
909
910 ev_periodic_init (&amp;hourly_tick, clock_cb, 0., 0., my_scheduler_cb);
911
912</pre>
913<p>Example: call a callback every hour, starting now:</p>
914<pre> struct ev_periodic hourly_tick;
915 ev_periodic_init (&amp;hourly_tick, clock_cb,
916 fmod (ev_now (loop), 3600.), 3600., 0);
917 ev_periodic_start (loop, &amp;hourly_tick);
918
919
920
921
922</pre>
681 923
682</div> 924</div>
683<h2 id="code_ev_signal_code_signal_me_when_a"><code>ev_signal</code> - signal me when a signal gets signalled</h2> 925<h2 id="code_ev_signal_code_signal_me_when_a"><code>ev_signal</code> - signal me when a signal gets signalled</h2>
684<div id="code_ev_signal_code_signal_me_when_a-2"> 926<div id="code_ev_signal_code_signal_me_when_a-2">
685<p>Signal watchers will trigger an event when the process receives a specific 927<p>Signal watchers will trigger an event when the process receives a specific
… …
699 <p>Configures the watcher to trigger on the given signal number (usually one 941 <p>Configures the watcher to trigger on the given signal number (usually one
700of the <code>SIGxxx</code> constants).</p> 942of the <code>SIGxxx</code> constants).</p>
701 </dd> 943 </dd>
702</dl> 944</dl>
703 945
946
947
948
949
704</div> 950</div>
705<h2 id="code_ev_child_code_wait_for_pid_stat"><code>ev_child</code> - wait for pid status changes</h2> 951<h2 id="code_ev_child_code_wait_for_pid_stat"><code>ev_child</code> - wait for pid status changes</h2>
706<div id="code_ev_child_code_wait_for_pid_stat-2"> 952<div id="code_ev_child_code_wait_for_pid_stat-2">
707<p>Child watchers trigger when your process receives a SIGCHLD in response to 953<p>Child watchers trigger when your process receives a SIGCHLD in response to
708some child status changes (most typically when a child of yours dies).</p> 954some child status changes (most typically when a child of yours dies).</p>
… …
716the status word (use the macros from <code>sys/wait.h</code> and see your systems 962the status word (use the macros from <code>sys/wait.h</code> and see your systems
717<code>waitpid</code> documentation). The <code>rpid</code> member contains the pid of the 963<code>waitpid</code> documentation). The <code>rpid</code> member contains the pid of the
718process causing the status change.</p> 964process causing the status change.</p>
719 </dd> 965 </dd>
720</dl> 966</dl>
967<p>Example: try to exit cleanly on SIGINT and SIGTERM.</p>
968<pre> static void
969 sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents)
970 {
971 ev_unloop (loop, EVUNLOOP_ALL);
972 }
973
974 struct ev_signal signal_watcher;
975 ev_signal_init (&amp;signal_watcher, sigint_cb, SIGINT);
976 ev_signal_start (loop, &amp;sigint_cb);
977
978
979
980
981</pre>
721 982
722</div> 983</div>
723<h2 id="code_ev_idle_code_when_you_ve_got_no"><code>ev_idle</code> - when you've got nothing better to do</h2> 984<h2 id="code_ev_idle_code_when_you_ve_got_no"><code>ev_idle</code> - when you've got nothing better to do</h2>
724<div id="code_ev_idle_code_when_you_ve_got_no-2"> 985<div id="code_ev_idle_code_when_you_ve_got_no-2">
725<p>Idle watchers trigger events when there are no other events are pending 986<p>Idle watchers trigger events when there are no other events are pending
… …
741 <p>Initialises and configures the idle watcher - it has no parameters of any 1002 <p>Initialises and configures the idle watcher - it has no parameters of any
742kind. There is a <code>ev_idle_set</code> macro, but using it is utterly pointless, 1003kind. There is a <code>ev_idle_set</code> macro, but using it is utterly pointless,
743believe me.</p> 1004believe me.</p>
744 </dd> 1005 </dd>
745</dl> 1006</dl>
1007<p>Example: dynamically allocate an <code>ev_idle</code>, start it, and in the
1008callback, free it. Alos, use no error checking, as usual.</p>
1009<pre> static void
1010 idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents)
1011 {
1012 free (w);
1013 // now do something you wanted to do when the program has
1014 // no longer asnything immediate to do.
1015 }
1016
1017 struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle));
1018 ev_idle_init (idle_watcher, idle_cb);
1019 ev_idle_start (loop, idle_cb);
1020
1021
1022
1023
1024</pre>
746 1025
747</div> 1026</div>
748<h2 id="code_ev_prepare_code_and_code_ev_che"><code>ev_prepare</code> and <code>ev_check</code> - customise your event loop</h2> 1027<h2 id="code_ev_prepare_code_and_code_ev_che"><code>ev_prepare</code> and <code>ev_check</code> - customise your event loop</h2>
749<div id="code_ev_prepare_code_and_code_ev_che-2"> 1028<div id="code_ev_prepare_code_and_code_ev_che-2">
750<p>Prepare and check watchers are usually (but not always) used in tandem: 1029<p>Prepare and check watchers are usually (but not always) used in tandem:
751prepare watchers get invoked before the process blocks and check watchers 1030prepare watchers get invoked before the process blocks and check watchers
752afterwards.</p> 1031afterwards.</p>
753<p>Their main purpose is to integrate other event mechanisms into libev. This 1032<p>Their main purpose is to integrate other event mechanisms into libev and
754could be used, for example, to track variable changes, implement your own 1033their use is somewhat advanced. This could be used, for example, to track
755watchers, integrate net-snmp or a coroutine library and lots more.</p> 1034variable changes, implement your own watchers, integrate net-snmp or a
1035coroutine library and lots more.</p>
756<p>This is done by examining in each prepare call which file descriptors need 1036<p>This is done by examining in each prepare call which file descriptors need
757to be watched by the other library, registering <code>ev_io</code> watchers for 1037to be watched by the other library, registering <code>ev_io</code> watchers for
758them and starting an <code>ev_timer</code> watcher for any timeouts (many libraries 1038them and starting an <code>ev_timer</code> watcher for any timeouts (many libraries
759provide just this functionality). Then, in the check watcher you check for 1039provide just this functionality). Then, in the check watcher you check for
760any events that occured (by checking the pending status of all watchers 1040any events that occured (by checking the pending status of all watchers
… …
776 <p>Initialises and configures the prepare or check watcher - they have no 1056 <p>Initialises and configures the prepare or check watcher - they have no
777parameters of any kind. There are <code>ev_prepare_set</code> and <code>ev_check_set</code> 1057parameters of any kind. There are <code>ev_prepare_set</code> and <code>ev_check_set</code>
778macros, but using them is utterly, utterly and completely pointless.</p> 1058macros, but using them is utterly, utterly and completely pointless.</p>
779 </dd> 1059 </dd>
780</dl> 1060</dl>
1061<p>Example: *TODO*.</p>
1062
1063
1064
1065
1066
1067</div>
1068<h2 id="code_ev_embed_code_when_one_backend_"><code>ev_embed</code> - when one backend isn't enough</h2>
1069<div id="code_ev_embed_code_when_one_backend_-2">
1070<p>This is a rather advanced watcher type that lets you embed one event loop
1071into another.</p>
1072<p>There are primarily two reasons you would want that: work around bugs and
1073prioritise I/O.</p>
1074<p>As an example for a bug workaround, the kqueue backend might only support
1075sockets on some platform, so it is unusable as generic backend, but you
1076still want to make use of it because you have many sockets and it scales
1077so nicely. In this case, you would create a kqueue-based loop and embed it
1078into your default loop (which might use e.g. poll). Overall operation will
1079be a bit slower because first libev has to poll and then call kevent, but
1080at least you can use both at what they are best.</p>
1081<p>As for prioritising I/O: rarely you have the case where some fds have
1082to be watched and handled very quickly (with low latency), and even
1083priorities and idle watchers might have too much overhead. In this case
1084you would put all the high priority stuff in one loop and all the rest in
1085a second one, and embed the second one in the first.</p>
1086<p>As long as the watcher is started it will automatically handle events. The
1087callback will be invoked whenever some events have been handled. You can
1088set the callback to <code>0</code> to avoid having to specify one if you are not
1089interested in that.</p>
1090<p>Also, there have not currently been made special provisions for forking:
1091when you fork, you not only have to call <code>ev_loop_fork</code> on both loops,
1092but you will also have to stop and restart any <code>ev_embed</code> watchers
1093yourself.</p>
1094<p>Unfortunately, not all backends are embeddable, only the ones returned by
1095<code>ev_embeddable_backends</code> are, which, unfortunately, does not include any
1096portable one.</p>
1097<p>So when you want to use this feature you will always have to be prepared
1098that you cannot get an embeddable loop. The recommended way to get around
1099this is to have a separate variables for your embeddable loop, try to
1100create it, and if that fails, use the normal loop for everything:</p>
1101<pre> struct ev_loop *loop_hi = ev_default_init (0);
1102 struct ev_loop *loop_lo = 0;
1103 struct ev_embed embed;
1104
1105 // see if there is a chance of getting one that works
1106 // (remember that a flags value of 0 means autodetection)
1107 loop_lo = ev_embeddable_backends () &amp; ev_recommended_backends ()
1108 ? ev_loop_new (ev_embeddable_backends () &amp; ev_recommended_backends ())
1109 : 0;
1110
1111 // if we got one, then embed it, otherwise default to loop_hi
1112 if (loop_lo)
1113 {
1114 ev_embed_init (&amp;embed, 0, loop_lo);
1115 ev_embed_start (loop_hi, &amp;embed);
1116 }
1117 else
1118 loop_lo = loop_hi;
1119
1120</pre>
1121<dl>
1122 <dt>ev_embed_init (ev_embed *, callback, struct ev_loop *loop)</dt>
1123 <dt>ev_embed_set (ev_embed *, callback, struct ev_loop *loop)</dt>
1124 <dd>
1125 <p>Configures the watcher to embed the given loop, which must be embeddable.</p>
1126 </dd>
1127</dl>
1128
1129
1130
1131
781 1132
782</div> 1133</div>
783<h1 id="OTHER_FUNCTIONS">OTHER FUNCTIONS</h1><p><a href="#TOP" class="toplink">Top</a></p> 1134<h1 id="OTHER_FUNCTIONS">OTHER FUNCTIONS</h1><p><a href="#TOP" class="toplink">Top</a></p>
784<div id="OTHER_FUNCTIONS_CONTENT"> 1135<div id="OTHER_FUNCTIONS_CONTENT">
785<p>There are some other functions of possible interest. Described. Here. Now.</p> 1136<p>There are some other functions of possible interest. Described. Here. Now.</p>
… …
829 <dd> 1180 <dd>
830 <p>Feed an event as if the given signal occured (loop must be the default loop!).</p> 1181 <p>Feed an event as if the given signal occured (loop must be the default loop!).</p>
831 </dd> 1182 </dd>
832</dl> 1183</dl>
833 1184
1185
1186
1187
1188
834</div> 1189</div>
835<h1 id="LIBEVENT_EMULATION">LIBEVENT EMULATION</h1><p><a href="#TOP" class="toplink">Top</a></p> 1190<h1 id="LIBEVENT_EMULATION">LIBEVENT EMULATION</h1><p><a href="#TOP" class="toplink">Top</a></p>
836<div id="LIBEVENT_EMULATION_CONTENT"> 1191<div id="LIBEVENT_EMULATION_CONTENT">
837<p>Libev offers a compatibility emulation layer for libevent. It cannot 1192<p>Libev offers a compatibility emulation layer for libevent. It cannot
838emulate the internals of libevent, so here are some usage hints:</p> 1193emulate the internals of libevent, so here are some usage hints:</p>

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