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4 | <head> |
4 | <head> |
5 | <title>libev</title> |
5 | <title>libev</title> |
6 | <meta name="description" content="Pod documentation for libev" /> |
6 | <meta name="description" content="Pod documentation for libev" /> |
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13 | <div class="pod"> |
13 | <div class="pod"> |
14 | <!-- INDEX START --> |
14 | <!-- INDEX START --> |
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123 | <p>Usually, it's a good idea to terminate if the major versions mismatch, |
123 | <p>Usually, it's a good idea to terminate if the major versions mismatch, |
124 | as this indicates an incompatible change. Minor versions are usually |
124 | as this indicates an incompatible change. Minor versions are usually |
125 | compatible to older versions, so a larger minor version alone is usually |
125 | compatible to older versions, so a larger minor version alone is usually |
126 | not a problem.</p> |
126 | not a problem.</p> |
127 | </dd> |
127 | </dd> |
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128 | <dt>unsigned int ev_supported_backends ()</dt> |
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129 | <dd> |
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130 | <p>Return the set of all backends (i.e. their corresponding <code>EV_BACKEND_*</code> |
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131 | value) compiled into this binary of libev (independent of their |
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132 | availability on the system you are running on). See <code>ev_default_loop</code> for |
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133 | a description of the set values.</p> |
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134 | </dd> |
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135 | <dt>unsigned int ev_recommended_backends ()</dt> |
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136 | <dd> |
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137 | <p>Return the set of all backends compiled into this binary of libev and also |
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138 | recommended for this platform. This set is often smaller than the one |
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139 | returned by <code>ev_supported_backends</code>, as for example kqueue is broken on |
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140 | most BSDs and will not be autodetected unless you explicitly request it |
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141 | (assuming you know what you are doing). This is the set of backends that |
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142 | libev will probe for if you specify no backends explicitly.</p> |
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143 | </dd> |
128 | <dt>ev_set_allocator (void *(*cb)(void *ptr, long size))</dt> |
144 | <dt>ev_set_allocator (void *(*cb)(void *ptr, long size))</dt> |
129 | <dd> |
145 | <dd> |
130 | <p>Sets the allocation function to use (the prototype is similar to the |
146 | <p>Sets the allocation function to use (the prototype is similar to the |
131 | realloc C function, the semantics are identical). It is used to allocate |
147 | realloc C function, the semantics are identical). It is used to allocate |
132 | and free memory (no surprises here). If it returns zero when memory |
148 | and free memory (no surprises here). If it returns zero when memory |
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164 | <dt>struct ev_loop *ev_default_loop (unsigned int flags)</dt> |
180 | <dt>struct ev_loop *ev_default_loop (unsigned int flags)</dt> |
165 | <dd> |
181 | <dd> |
166 | <p>This will initialise the default event loop if it hasn't been initialised |
182 | <p>This will initialise the default event loop if it hasn't been initialised |
167 | yet and return it. If the default loop could not be initialised, returns |
183 | yet and return it. If the default loop could not be initialised, returns |
168 | false. If it already was initialised it simply returns it (and ignores the |
184 | false. If it already was initialised it simply returns it (and ignores the |
169 | flags).</p> |
185 | flags. 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 |
186 | <p>If you don't know what event loop to use, use the one returned from this |
171 | function.</p> |
187 | function.</p> |
172 | <p>The flags argument can be used to specify special behaviour or specific |
188 | <p>The flags argument can be used to specify special behaviour or specific |
173 | backends to use, and is usually specified as 0 (or EVFLAG_AUTO).</p> |
189 | backends to use, and is usually specified as <code>0</code> (or <code>EVFLAG_AUTO</code>).</p> |
174 | <p>It supports the following flags:</p> |
190 | <p>The following flags are supported:</p> |
175 | <p> |
191 | <p> |
176 | <dl> |
192 | <dl> |
177 | <dt><code>EVFLAG_AUTO</code></dt> |
193 | <dt><code>EVFLAG_AUTO</code></dt> |
178 | <dd> |
194 | <dd> |
179 | <p>The default flags value. Use this if you have no clue (it's the right |
195 | <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 |
202 | <code>LIBEV_FLAGS</code>. Otherwise (the default), this environment variable will |
187 | override the flags completely if it is found in the environment. This is |
203 | override the flags completely if it is found in the environment. This is |
188 | useful to try out specific backends to test their performance, or to work |
204 | useful to try out specific backends to test their performance, or to work |
189 | around bugs.</p> |
205 | around bugs.</p> |
190 | </dd> |
206 | </dd> |
191 | <dt><code>EVMETHOD_SELECT</code> (value 1, portable select backend)</dt> |
207 | <dt><code>EVBACKEND_SELECT</code> (value 1, portable select backend)</dt> |
192 | <dd> |
208 | <dd> |
193 | <p>This is your standard select(2) backend. Not <i>completely</i> standard, as |
209 | <p>This is your standard select(2) backend. Not <i>completely</i> standard, as |
194 | libev tries to roll its own fd_set with no limits on the number of fds, |
210 | libev tries to roll its own fd_set with no limits on the number of fds, |
195 | but if that fails, expect a fairly low limit on the number of fds when |
211 | but if that fails, expect a fairly low limit on the number of fds when |
196 | using this backend. It doesn't scale too well (O(highest_fd)), but its usually |
212 | using this backend. It doesn't scale too well (O(highest_fd)), but its usually |
197 | the fastest backend for a low number of fds.</p> |
213 | the fastest backend for a low number of fds.</p> |
198 | </dd> |
214 | </dd> |
199 | <dt><code>EVMETHOD_POLL</code> (value 2, poll backend, available everywhere except on windows)</dt> |
215 | <dt><code>EVBACKEND_POLL</code> (value 2, poll backend, available everywhere except on windows)</dt> |
200 | <dd> |
216 | <dd> |
201 | <p>And this is your standard poll(2) backend. It's more complicated than |
217 | <p>And this is your standard poll(2) backend. It's more complicated than |
202 | select, but handles sparse fds better and has no artificial limit on the |
218 | select, but handles sparse fds better and has no artificial limit on the |
203 | number of fds you can use (except it will slow down considerably with a |
219 | number of fds you can use (except it will slow down considerably with a |
204 | lot of inactive fds). It scales similarly to select, i.e. O(total_fds).</p> |
220 | lot of inactive fds). It scales similarly to select, i.e. O(total_fds).</p> |
205 | </dd> |
221 | </dd> |
206 | <dt><code>EVMETHOD_EPOLL</code> (value 4, Linux)</dt> |
222 | <dt><code>EVBACKEND_EPOLL</code> (value 4, Linux)</dt> |
207 | <dd> |
223 | <dd> |
208 | <p>For few fds, this backend is a bit little slower than poll and select, |
224 | <p>For few fds, this backend is a bit little slower than poll and select, |
209 | but it scales phenomenally better. While poll and select usually scale like |
225 | but it scales phenomenally better. While poll and select usually scale like |
210 | O(total_fds) where n is the total number of fds (or the highest fd), epoll scales |
226 | O(total_fds) where n is the total number of fds (or the highest fd), epoll scales |
211 | either O(1) or O(active_fds).</p> |
227 | either O(1) or O(active_fds).</p> |
212 | <p>While stopping and starting an I/O watcher in the same iteration will |
228 | <p>While stopping and starting an I/O watcher in the same iteration will |
213 | result in some caching, there is still a syscall per such incident |
229 | result 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 |
230 | (because the fd could point to a different file description now), so its |
215 | best to avoid that. Also, dup()ed file descriptors might not work very |
231 | best to avoid that. Also, dup()ed file descriptors might not work very |
216 | well if you register events for both fds.</p> |
232 | well if you register events for both fds.</p> |
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233 | <p>Please note that epoll sometimes generates spurious notifications, so you |
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234 | need to use non-blocking I/O or other means to avoid blocking when no data |
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235 | (or space) is available.</p> |
217 | </dd> |
236 | </dd> |
218 | <dt><code>EVMETHOD_KQUEUE</code> (value 8, most BSD clones)</dt> |
237 | <dt><code>EVBACKEND_KQUEUE</code> (value 8, most BSD clones)</dt> |
219 | <dd> |
238 | <dd> |
220 | <p>Kqueue deserves special mention, as at the time of this writing, it |
239 | <p>Kqueue deserves special mention, as at the time of this writing, it |
221 | was broken on all BSDs except NetBSD (usually it doesn't work with |
240 | was broken on all BSDs except NetBSD (usually it doesn't work with |
222 | anything but sockets and pipes, except on Darwin, where of course its |
241 | anything but sockets and pipes, except on Darwin, where of course its |
223 | completely useless). For this reason its not being "autodetected" unless |
242 | completely useless). For this reason its not being "autodetected" |
224 | you explicitly specify the flags (i.e. you don't use EVFLAG_AUTO).</p> |
243 | unless you explicitly specify it explicitly in the flags (i.e. using |
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244 | <code>EVBACKEND_KQUEUE</code>).</p> |
225 | <p>It scales in the same way as the epoll backend, but the interface to the |
245 | <p>It scales in the same way as the epoll backend, but the interface to the |
226 | kernel is more efficient (which says nothing about its actual speed, of |
246 | kernel is more efficient (which says nothing about its actual speed, of |
227 | course). While starting and stopping an I/O watcher does not cause an |
247 | course). While starting and stopping an I/O watcher does not cause an |
228 | extra syscall as with epoll, it still adds up to four event changes per |
248 | extra syscall as with epoll, it still adds up to four event changes per |
229 | incident, so its best to avoid that.</p> |
249 | incident, so its best to avoid that.</p> |
230 | </dd> |
250 | </dd> |
231 | <dt><code>EVMETHOD_DEVPOLL</code> (value 16, Solaris 8)</dt> |
251 | <dt><code>EVBACKEND_DEVPOLL</code> (value 16, Solaris 8)</dt> |
232 | <dd> |
252 | <dd> |
233 | <p>This is not implemented yet (and might never be).</p> |
253 | <p>This is not implemented yet (and might never be).</p> |
234 | </dd> |
254 | </dd> |
235 | <dt><code>EVMETHOD_PORT</code> (value 32, Solaris 10)</dt> |
255 | <dt><code>EVBACKEND_PORT</code> (value 32, Solaris 10)</dt> |
236 | <dd> |
256 | <dd> |
237 | <p>This uses the Solaris 10 port mechanism. As with everything on Solaris, |
257 | <p>This uses the Solaris 10 port mechanism. As with everything on Solaris, |
238 | it's really slow, but it still scales very well (O(active_fds)).</p> |
258 | it's really slow, but it still scales very well (O(active_fds)).</p> |
239 | </dd> |
259 | <p>Please note that solaris ports can result in a lot of spurious |
240 | <dt><code>EVMETHOD_ALL</code></dt> |
260 | notifications, so you need to use non-blocking I/O or other means to avoid |
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261 | blocking when no data (or space) is available.</p> |
241 | <dd> |
262 | </dd> |
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263 | <dt><code>EVBACKEND_ALL</code></dt> |
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264 | <dd> |
242 | <p>Try all backends (even potentially broken ones). Since this is a mask, you |
265 | <p>Try all backends (even potentially broken ones that wouldn't be tried |
243 | can do stuff like <code>EVMETHOD_ALL & ~EVMETHOD_KQUEUE</code>.</p> |
266 | with <code>EVFLAG_AUTO</code>). Since this is a mask, you can do stuff such as |
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267 | <code>EVBACKEND_ALL & ~EVBACKEND_KQUEUE</code>.</p> |
244 | </dd> |
268 | </dd> |
245 | </dl> |
269 | </dl> |
246 | </p> |
270 | </p> |
247 | <p>If one or more of these are ored into the flags value, then only these |
271 | <p>If one or more of these are ored into the flags value, then only these |
248 | backends will be tried (in the reverse order as given here). If none are |
272 | backends will be tried (in the reverse order as given here). If none are |
249 | specified, most compiled-in backend will be tried, usually in reverse |
273 | specified, most compiled-in backend will be tried, usually in reverse |
250 | order of their flag values :)</p> |
274 | order of their flag values :)</p> |
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275 | <p>The most typical usage is like this:</p> |
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276 | <pre> if (!ev_default_loop (0)) |
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277 | fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?"); |
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278 | |
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279 | </pre> |
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280 | <p>Restrict libev to the select and poll backends, and do not allow |
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281 | environment settings to be taken into account:</p> |
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282 | <pre> ev_default_loop (EVBACKEND_POLL | EVBACKEND_SELECT | EVFLAG_NOENV); |
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283 | |
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284 | </pre> |
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285 | <p>Use whatever libev has to offer, but make sure that kqueue is used if |
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286 | available (warning, breaks stuff, best use only with your own private |
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287 | event loop and only if you know the OS supports your types of fds):</p> |
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288 | <pre> ev_default_loop (ev_recommended_backends () | EVBACKEND_KQUEUE); |
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289 | |
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290 | </pre> |
251 | </dd> |
291 | </dd> |
252 | <dt>struct ev_loop *ev_loop_new (unsigned int flags)</dt> |
292 | <dt>struct ev_loop *ev_loop_new (unsigned int flags)</dt> |
253 | <dd> |
293 | <dd> |
254 | <p>Similar to <code>ev_default_loop</code>, but always creates a new event loop that is |
294 | <p>Similar to <code>ev_default_loop</code>, but always creates a new event loop that is |
255 | always distinct from the default loop. Unlike the default loop, it cannot |
295 | always distinct from the default loop. Unlike the default loop, it cannot |
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271 | <dd> |
311 | <dd> |
272 | <p>This function reinitialises the kernel state for backends that have |
312 | <p>This function reinitialises the kernel state for backends that have |
273 | one. Despite the name, you can call it anytime, but it makes most sense |
313 | one. Despite the name, you can call it anytime, but it makes most sense |
274 | after forking, in either the parent or child process (or both, but that |
314 | after forking, in either the parent or child process (or both, but that |
275 | again makes little sense).</p> |
315 | again makes little sense).</p> |
276 | <p>You <i>must</i> call this function after forking if and only if you want to |
316 | <p>You <i>must</i> call this function in the child process after forking if and |
277 | use the event library in both processes. If you just fork+exec, you don't |
317 | only if you want to use the event library in both processes. If you just |
278 | have to call it.</p> |
318 | fork+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 |
319 | <p>The function itself is quite fast and it's usually not a problem to call |
280 | it just in case after a fork. To make this easy, the function will fit in |
320 | it just in case after a fork. To make this easy, the function will fit in |
281 | quite nicely into a call to <code>pthread_atfork</code>:</p> |
321 | quite nicely into a call to <code>pthread_atfork</code>:</p> |
282 | <pre> pthread_atfork (0, 0, ev_default_fork); |
322 | <pre> pthread_atfork (0, 0, ev_default_fork); |
283 | |
323 | |
284 | </pre> |
324 | </pre> |
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325 | <p>At the moment, <code>EVBACKEND_SELECT</code> and <code>EVBACKEND_POLL</code> are safe to use |
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326 | without calling this function, so if you force one of those backends you |
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327 | do not need to care.</p> |
285 | </dd> |
328 | </dd> |
286 | <dt>ev_loop_fork (loop)</dt> |
329 | <dt>ev_loop_fork (loop)</dt> |
287 | <dd> |
330 | <dd> |
288 | <p>Like <code>ev_default_fork</code>, but acts on an event loop created by |
331 | <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 |
332 | <code>ev_loop_new</code>. Yes, you have to call this on every allocated event loop |
290 | after fork, and how you do this is entirely your own problem.</p> |
333 | after fork, and how you do this is entirely your own problem.</p> |
291 | </dd> |
334 | </dd> |
292 | <dt>unsigned int ev_method (loop)</dt> |
335 | <dt>unsigned int ev_backend (loop)</dt> |
293 | <dd> |
336 | <dd> |
294 | <p>Returns one of the <code>EVMETHOD_*</code> flags indicating the event backend in |
337 | <p>Returns one of the <code>EVBACKEND_*</code> flags indicating the event backend in |
295 | use.</p> |
338 | use.</p> |
296 | </dd> |
339 | </dd> |
297 | <dt>ev_tstamp ev_now (loop)</dt> |
340 | <dt>ev_tstamp ev_now (loop)</dt> |
298 | <dd> |
341 | <dd> |
299 | <p>Returns the current "event loop time", which is the time the event loop |
342 | <p>Returns the current "event loop time", which is the time the event loop |
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305 | <dt>ev_loop (loop, int flags)</dt> |
348 | <dt>ev_loop (loop, int flags)</dt> |
306 | <dd> |
349 | <dd> |
307 | <p>Finally, this is it, the event handler. This function usually is called |
350 | <p>Finally, this is it, the event handler. This function usually is called |
308 | after you initialised all your watchers and you want to start handling |
351 | after you initialised all your watchers and you want to start handling |
309 | events.</p> |
352 | events.</p> |
310 | <p>If the flags argument is specified as 0, it will not return until either |
353 | <p>If the flags argument is specified as <code>0</code>, it will not return until |
311 | no event watchers are active anymore or <code>ev_unloop</code> was called.</p> |
354 | either no event watchers are active anymore or <code>ev_unloop</code> was called.</p> |
312 | <p>A flags value of <code>EVLOOP_NONBLOCK</code> will look for new events, will handle |
355 | <p>A flags value of <code>EVLOOP_NONBLOCK</code> will look for new events, will handle |
313 | those events and any outstanding ones, but will not block your process in |
356 | those events and any outstanding ones, but will not block your process in |
314 | case there are no events and will return after one iteration of the loop.</p> |
357 | case 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 |
358 | <p>A flags value of <code>EVLOOP_ONESHOT</code> will look for new events (waiting if |
316 | neccessary) and will handle those and any outstanding ones. It will block |
359 | neccessary) and will handle those and any outstanding ones. It will block |
317 | your process until at least one new event arrives, and will return after |
360 | your process until at least one new event arrives, and will return after |
318 | one iteration of the loop.</p> |
361 | one 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 |
362 | external event in conjunction with something not expressible using other |
320 | constructs, but the <code>prepare</code> and <code>check</code> watchers provide a better and |
363 | libev watchers. However, a pair of <code>ev_prepare</code>/<code>ev_check</code> watchers is |
321 | more generic mechanism.</p> |
364 | usually a better approach for this kind of thing.</p> |
322 | <p>Here are the gory details of what ev_loop does:</p> |
365 | <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. |
366 | <pre> * If there are no active watchers (reference count is zero), return. |
324 | 2. Queue and immediately call all prepare watchers. |
367 | - Queue prepare watchers and then call all outstanding watchers. |
325 | 3. If we have been forked, recreate the kernel state. |
368 | - If we have been forked, recreate the kernel state. |
326 | 4. Update the kernel state with all outstanding changes. |
369 | - Update the kernel state with all outstanding changes. |
327 | 5. Update the "event loop time". |
370 | - Update the "event loop time". |
328 | 6. Calculate for how long to block. |
371 | - Calculate for how long to block. |
329 | 7. Block the process, waiting for events. |
372 | - Block the process, waiting for any events. |
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373 | - Queue all outstanding I/O (fd) events. |
330 | 8. Update the "event loop time" and do time jump handling. |
374 | - Update the "event loop time" and do time jump handling. |
331 | 9. Queue all outstanding timers. |
375 | - Queue all outstanding timers. |
332 | 10. Queue all outstanding periodics. |
376 | - Queue all outstanding periodics. |
333 | 11. If no events are pending now, queue all idle watchers. |
377 | - If no events are pending now, queue all idle watchers. |
334 | 12. Queue all check watchers. |
378 | - Queue all check watchers. |
335 | 13. Call all queued watchers in reverse order (i.e. check watchers first). |
379 | - Call all queued watchers in reverse order (i.e. check watchers first). |
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380 | Signals and child watchers are implemented as I/O watchers, and will |
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381 | 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 |
382 | - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
337 | was used, return, otherwise continue with step #1. |
383 | were used, return, otherwise continue with step *. |
338 | |
384 | |
339 | </pre> |
385 | </pre> |
340 | </dd> |
386 | </dd> |
341 | <dt>ev_unloop (loop, how)</dt> |
387 | <dt>ev_unloop (loop, how)</dt> |
342 | <dd> |
388 | <dd> |
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397 | with a watcher-specific start function (<code>ev_<type>_start (loop, watcher |
443 | with a watcher-specific start function (<code>ev_<type>_start (loop, watcher |
398 | *)</code>), and you can stop watching for events at any time by calling the |
444 | *)</code>), and you can stop watching for events at any time by calling the |
399 | corresponding stop function (<code>ev_<type>_stop (loop, watcher *)</code>.</p> |
445 | corresponding stop function (<code>ev_<type>_stop (loop, watcher *)</code>.</p> |
400 | <p>As long as your watcher is active (has been started but not stopped) you |
446 | <p>As long as your watcher is active (has been started but not stopped) you |
401 | must not touch the values stored in it. Most specifically you must never |
447 | must not touch the values stored in it. Most specifically you must never |
402 | reinitialise it or call its set method.</p> |
448 | reinitialise it or call its set macro.</p> |
403 | <p>You can check whether an event is active by calling the <code>ev_is_active |
449 | <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 |
450 | (watcher *)</code> macro. To see whether an event is outstanding (but the |
405 | callback for it has not been called yet) you can use the <code>ev_is_pending |
451 | callback for it has not been called yet) you can use the <code>ev_is_pending |
406 | (watcher *)</code> macro.</p> |
452 | (watcher *)</code> macro.</p> |
407 | <p>Each and every callback receives the event loop pointer as first, the |
453 | <p>Each and every callback receives the event loop pointer as first, the |
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519 | (the linux epoll backend is a notable example) cannot handle dup'ed file |
565 | (the linux epoll backend is a notable example) cannot handle dup'ed file |
520 | descriptors correctly if you register interest in two or more fds pointing |
566 | descriptors correctly if you register interest in two or more fds pointing |
521 | to the same underlying file/socket etc. description (that is, they share |
567 | to the same underlying file/socket etc. description (that is, they share |
522 | the same underlying "file open").</p> |
568 | the same underlying "file open").</p> |
523 | <p>If you must do this, then force the use of a known-to-be-good backend |
569 | <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 |
570 | (at the time of this writing, this includes only <code>EVBACKEND_SELECT</code> and |
525 | EVMETHOD_POLL).</p> |
571 | <code>EVBACKEND_POLL</code>).</p> |
526 | <dl> |
572 | <dl> |
527 | <dt>ev_io_init (ev_io *, callback, int fd, int events)</dt> |
573 | <dt>ev_io_init (ev_io *, callback, int fd, int events)</dt> |
528 | <dt>ev_io_set (ev_io *, int fd, int events)</dt> |
574 | <dt>ev_io_set (ev_io *, int fd, int events)</dt> |
529 | <dd> |
575 | <dd> |
530 | <p>Configures an <code>ev_io</code> watcher. The fd is the file descriptor to rceeive |
576 | <p>Configures an <code>ev_io</code> watcher. The fd is the file descriptor to rceeive |
531 | events for and events is either <code>EV_READ</code>, <code>EV_WRITE</code> or <code>EV_READ | |
577 | events for and events is either <code>EV_READ</code>, <code>EV_WRITE</code> or <code>EV_READ | |
532 | EV_WRITE</code> to receive the given events.</p> |
578 | EV_WRITE</code> to receive the given events.</p> |
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579 | <p>Please note that most of the more scalable backend mechanisms (for example |
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580 | epoll and solaris ports) can result in spurious readyness notifications |
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581 | for file descriptors, so you practically need to use non-blocking I/O (and |
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582 | treat callback invocation as hint only), or retest separately with a safe |
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583 | interface before doing I/O (XLib can do this), or force the use of either |
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584 | <code>EVBACKEND_SELECT</code> or <code>EVBACKEND_POLL</code>, which don't suffer from this |
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585 | problem. Also note that it is quite easy to have your callback invoked |
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586 | when the readyness condition is no longer valid even when employing |
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587 | typical ways of handling events, so its a good idea to use non-blocking |
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588 | I/O unconditionally.</p> |
533 | </dd> |
589 | </dd> |
534 | </dl> |
590 | </dl> |
535 | |
591 | |
536 | </div> |
592 | </div> |
537 | <h2 id="code_ev_timer_code_relative_and_opti"><code>ev_timer</code> - relative and optionally recurring timeouts</h2> |
593 | <h2 id="code_ev_timer_code_relative_and_opti"><code>ev_timer</code> - relative and optionally recurring timeouts</h2> |