… | |
… | |
25 | |
25 | |
26 | Libev supports select, poll, the linux-specific epoll and the bsd-specific |
26 | Libev supports select, poll, the linux-specific epoll and the bsd-specific |
27 | kqueue mechanisms for file descriptor events, relative timers, absolute |
27 | kqueue mechanisms for file descriptor events, relative timers, absolute |
28 | timers with customised rescheduling, signal events, process status change |
28 | timers with customised rescheduling, signal events, process status change |
29 | events (related to SIGCHLD), and event watchers dealing with the event |
29 | events (related to SIGCHLD), and event watchers dealing with the event |
30 | loop mechanism itself (idle, prepare and check watchers). |
30 | loop mechanism itself (idle, prepare and check watchers). It also is quite |
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31 | fast (see this L<benchmark|http://libev.schmorp.de/bench.html> comparing |
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32 | it to libevent for example). |
31 | |
33 | |
32 | =head1 CONVENTIONS |
34 | =head1 CONVENTIONS |
33 | |
35 | |
34 | Libev is very configurable. In this manual the default configuration |
36 | Libev is very configurable. In this manual the default configuration |
35 | will be described, which supports multiple event loops. For more info |
37 | will be described, which supports multiple event loops. For more info |
36 | about various configuraiton options please have a look at the file |
38 | about various configuration options please have a look at the file |
37 | F<README.embed> in the libev distribution. If libev was configured without |
39 | F<README.embed> in the libev distribution. If libev was configured without |
38 | support for multiple event loops, then all functions taking an initial |
40 | support for multiple event loops, then all functions taking an initial |
39 | argument of name C<loop> (which is always of type C<struct ev_loop *>) |
41 | argument of name C<loop> (which is always of type C<struct ev_loop *>) |
40 | will not have this argument. |
42 | will not have this argument. |
41 | |
43 | |
42 | =head1 TIME AND OTHER GLOBAL FUNCTIONS |
44 | =head1 TIME REPRESENTATION |
43 | |
45 | |
44 | Libev represents time as a single floating point number, representing the |
46 | Libev represents time as a single floating point number, representing the |
45 | (fractional) number of seconds since the (POSIX) epoch (somewhere near |
47 | (fractional) number of seconds since the (POSIX) epoch (somewhere near |
46 | the beginning of 1970, details are complicated, don't ask). This type is |
48 | the beginning of 1970, details are complicated, don't ask). This type is |
47 | called C<ev_tstamp>, which is what you should use too. It usually aliases |
49 | called C<ev_tstamp>, which is what you should use too. It usually aliases |
48 | to the double type in C. |
50 | to the double type in C. |
49 | |
51 | |
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52 | =head1 GLOBAL FUNCTIONS |
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53 | |
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54 | These functions can be called anytime, even before initialising the |
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55 | library in any way. |
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56 | |
50 | =over 4 |
57 | =over 4 |
51 | |
58 | |
52 | =item ev_tstamp ev_time () |
59 | =item ev_tstamp ev_time () |
53 | |
60 | |
54 | Returns the current time as libev would use it. |
61 | Returns the current time as libev would use it. Please note that the |
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62 | C<ev_now> function is usually faster and also often returns the timestamp |
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63 | you actually want to know. |
55 | |
64 | |
56 | =item int ev_version_major () |
65 | =item int ev_version_major () |
57 | |
66 | |
58 | =item int ev_version_minor () |
67 | =item int ev_version_minor () |
59 | |
68 | |
… | |
… | |
61 | you linked against by calling the functions C<ev_version_major> and |
70 | you linked against by calling the functions C<ev_version_major> and |
62 | C<ev_version_minor>. If you want, you can compare against the global |
71 | C<ev_version_minor>. If you want, you can compare against the global |
63 | symbols C<EV_VERSION_MAJOR> and C<EV_VERSION_MINOR>, which specify the |
72 | symbols C<EV_VERSION_MAJOR> and C<EV_VERSION_MINOR>, which specify the |
64 | version of the library your program was compiled against. |
73 | version of the library your program was compiled against. |
65 | |
74 | |
66 | Usually, its a good idea to terminate if the major versions mismatch, |
75 | Usually, it's a good idea to terminate if the major versions mismatch, |
67 | as this indicates an incompatible change. Minor versions are usually |
76 | as this indicates an incompatible change. Minor versions are usually |
68 | compatible to older versions, so a larger minor version alone is usually |
77 | compatible to older versions, so a larger minor version alone is usually |
69 | not a problem. |
78 | not a problem. |
70 | |
79 | |
71 | =item ev_set_allocator (void *(*cb)(void *ptr, long size)) |
80 | =item ev_set_allocator (void *(*cb)(void *ptr, long size)) |
72 | |
81 | |
73 | Sets the allocation function to use (the prototype is similar to the |
82 | Sets the allocation function to use (the prototype is similar to the |
74 | realloc function). It is used to allocate and free memory (no surprises |
83 | realloc C function, the semantics are identical). It is used to allocate |
75 | here). If it returns zero when memory needs to be allocated, the library |
84 | and free memory (no surprises here). If it returns zero when memory |
76 | might abort or take some potentially destructive action. The default is |
85 | needs to be allocated, the library might abort or take some potentially |
77 | your system realloc function. |
86 | destructive action. The default is your system realloc function. |
78 | |
87 | |
79 | You could override this function in high-availability programs to, say, |
88 | You could override this function in high-availability programs to, say, |
80 | free some memory if it cannot allocate memory, to use a special allocator, |
89 | free some memory if it cannot allocate memory, to use a special allocator, |
81 | or even to sleep a while and retry until some memory is available. |
90 | or even to sleep a while and retry until some memory is available. |
82 | |
91 | |
… | |
… | |
84 | |
93 | |
85 | Set the callback function to call on a retryable syscall error (such |
94 | Set the callback function to call on a retryable syscall error (such |
86 | as failed select, poll, epoll_wait). The message is a printable string |
95 | as failed select, poll, epoll_wait). The message is a printable string |
87 | indicating the system call or subsystem causing the problem. If this |
96 | indicating the system call or subsystem causing the problem. If this |
88 | callback is set, then libev will expect it to remedy the sitution, no |
97 | callback is set, then libev will expect it to remedy the sitution, no |
89 | matter what, when it returns. That is, libev will geenrally retry the |
98 | matter what, when it returns. That is, libev will generally retry the |
90 | requested operation, or, if the condition doesn't go away, do bad stuff |
99 | requested operation, or, if the condition doesn't go away, do bad stuff |
91 | (such as abort). |
100 | (such as abort). |
92 | |
101 | |
93 | =back |
102 | =back |
94 | |
103 | |
… | |
… | |
97 | An event loop is described by a C<struct ev_loop *>. The library knows two |
106 | An event loop is described by a C<struct ev_loop *>. The library knows two |
98 | types of such loops, the I<default> loop, which supports signals and child |
107 | types of such loops, the I<default> loop, which supports signals and child |
99 | events, and dynamically created loops which do not. |
108 | events, and dynamically created loops which do not. |
100 | |
109 | |
101 | If you use threads, a common model is to run the default event loop |
110 | If you use threads, a common model is to run the default event loop |
102 | in your main thread (or in a separate thrad) and for each thread you |
111 | in your main thread (or in a separate thread) and for each thread you |
103 | create, you also create another event loop. Libev itself does no lockign |
112 | create, you also create another event loop. Libev itself does no locking |
104 | whatsoever, so if you mix calls to different event loops, make sure you |
113 | whatsoever, so if you mix calls to the same event loop in different |
105 | lock (this is usually a bad idea, though, even if done right). |
114 | threads, make sure you lock (this is usually a bad idea, though, even if |
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115 | done correctly, because it's hideous and inefficient). |
106 | |
116 | |
107 | =over 4 |
117 | =over 4 |
108 | |
118 | |
109 | =item struct ev_loop *ev_default_loop (unsigned int flags) |
119 | =item struct ev_loop *ev_default_loop (unsigned int flags) |
110 | |
120 | |
… | |
… | |
115 | |
125 | |
116 | If you don't know what event loop to use, use the one returned from this |
126 | If you don't know what event loop to use, use the one returned from this |
117 | function. |
127 | function. |
118 | |
128 | |
119 | The flags argument can be used to specify special behaviour or specific |
129 | The flags argument can be used to specify special behaviour or specific |
120 | backends to use, and is usually specified as 0 (or EVFLAG_AUTO) |
130 | backends to use, and is usually specified as 0 (or EVFLAG_AUTO). |
121 | |
131 | |
122 | It supports the following flags: |
132 | It supports the following flags: |
123 | |
133 | |
124 | =over 4 |
134 | =over 4 |
125 | |
135 | |
126 | =item EVFLAG_AUTO |
136 | =item C<EVFLAG_AUTO> |
127 | |
137 | |
128 | The default flags value. Use this if you have no clue (its the right |
138 | The default flags value. Use this if you have no clue (it's the right |
129 | thing, believe me). |
139 | thing, believe me). |
130 | |
140 | |
131 | =item EVFLAG_NOENV |
141 | =item C<EVFLAG_NOENV> |
132 | |
142 | |
133 | If this flag bit is ored into the flag value then libev will I<not> look |
143 | If this flag bit is ored into the flag value (or the program runs setuid |
134 | at the environment variable C<LIBEV_FLAGS>. Otherwise (the default), this |
144 | or setgid) then libev will I<not> look at the environment variable |
135 | environment variable will override the flags completely. This is useful |
145 | C<LIBEV_FLAGS>. Otherwise (the default), this environment variable will |
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146 | override the flags completely if it is found in the environment. This is |
136 | to try out specific backends to tets their performance, or to work around |
147 | useful to try out specific backends to test their performance, or to work |
137 | bugs. |
148 | around bugs. |
138 | |
149 | |
139 | =item EVMETHOD_SELECT portable select backend |
150 | =item C<EVMETHOD_SELECT> (portable select backend) |
140 | |
151 | |
141 | =item EVMETHOD_POLL poll backend (everywhere except windows) |
152 | =item C<EVMETHOD_POLL> (poll backend, available everywhere except on windows) |
142 | |
153 | |
143 | =item EVMETHOD_EPOLL linux only |
154 | =item C<EVMETHOD_EPOLL> (linux only) |
144 | |
155 | |
145 | =item EVMETHOD_KQUEUE some bsds only |
156 | =item C<EVMETHOD_KQUEUE> (some bsds only) |
146 | |
157 | |
147 | =item EVMETHOD_DEVPOLL solaris 8 only |
158 | =item C<EVMETHOD_DEVPOLL> (solaris 8 only) |
148 | |
159 | |
149 | =item EVMETHOD_PORT solaris 10 only |
160 | =item C<EVMETHOD_PORT> (solaris 10 only) |
150 | |
161 | |
151 | If one or more of these are ored into the flags value, then only these |
162 | If one or more of these are ored into the flags value, then only these |
152 | backends will be tried (in the reverse order as given here). If one are |
163 | backends will be tried (in the reverse order as given here). If one are |
153 | specified, any backend will do. |
164 | specified, any backend will do. |
154 | |
165 | |
… | |
… | |
163 | |
174 | |
164 | =item ev_default_destroy () |
175 | =item ev_default_destroy () |
165 | |
176 | |
166 | Destroys the default loop again (frees all memory and kernel state |
177 | Destroys the default loop again (frees all memory and kernel state |
167 | etc.). This stops all registered event watchers (by not touching them in |
178 | etc.). This stops all registered event watchers (by not touching them in |
168 | any way whatsoever, although you cnanot rely on this :). |
179 | any way whatsoever, although you cannot rely on this :). |
169 | |
180 | |
170 | =item ev_loop_destroy (loop) |
181 | =item ev_loop_destroy (loop) |
171 | |
182 | |
172 | Like C<ev_default_destroy>, but destroys an event loop created by an |
183 | Like C<ev_default_destroy>, but destroys an event loop created by an |
173 | earlier call to C<ev_loop_new>. |
184 | earlier call to C<ev_loop_new>. |
… | |
… | |
181 | |
192 | |
182 | You I<must> call this function after forking if and only if you want to |
193 | You I<must> call this function after forking if and only if you want to |
183 | use the event library in both processes. If you just fork+exec, you don't |
194 | use the event library in both processes. If you just fork+exec, you don't |
184 | have to call it. |
195 | have to call it. |
185 | |
196 | |
186 | The function itself is quite fast and its usually not a problem to call |
197 | The function itself is quite fast and it's usually not a problem to call |
187 | it just in case after a fork. To make this easy, the function will fit in |
198 | it just in case after a fork. To make this easy, the function will fit in |
188 | quite nicely into a call to C<pthread_atfork>: |
199 | quite nicely into a call to C<pthread_atfork>: |
189 | |
200 | |
190 | pthread_atfork (0, 0, ev_default_fork); |
201 | pthread_atfork (0, 0, ev_default_fork); |
191 | |
202 | |
… | |
… | |
198 | =item unsigned int ev_method (loop) |
209 | =item unsigned int ev_method (loop) |
199 | |
210 | |
200 | Returns one of the C<EVMETHOD_*> flags indicating the event backend in |
211 | Returns one of the C<EVMETHOD_*> flags indicating the event backend in |
201 | use. |
212 | use. |
202 | |
213 | |
203 | =item ev_tstamp = ev_now (loop) |
214 | =item ev_tstamp ev_now (loop) |
204 | |
215 | |
205 | Returns the current "event loop time", which is the time the event loop |
216 | Returns the current "event loop time", which is the time the event loop |
206 | got events and started processing them. This timestamp does not change |
217 | got events and started processing them. This timestamp does not change |
207 | as long as callbacks are being processed, and this is also the base time |
218 | as long as callbacks are being processed, and this is also the base time |
208 | used for relative timers. You can treat it as the timestamp of the event |
219 | used for relative timers. You can treat it as the timestamp of the event |
… | |
… | |
217 | If the flags argument is specified as 0, it will not return until either |
228 | If the flags argument is specified as 0, it will not return until either |
218 | no event watchers are active anymore or C<ev_unloop> was called. |
229 | no event watchers are active anymore or C<ev_unloop> was called. |
219 | |
230 | |
220 | A flags value of C<EVLOOP_NONBLOCK> will look for new events, will handle |
231 | A flags value of C<EVLOOP_NONBLOCK> will look for new events, will handle |
221 | those events and any outstanding ones, but will not block your process in |
232 | those events and any outstanding ones, but will not block your process in |
222 | case there are no events. |
233 | case there are no events and will return after one iteration of the loop. |
223 | |
234 | |
224 | A flags value of C<EVLOOP_ONESHOT> will look for new events (waiting if |
235 | A flags value of C<EVLOOP_ONESHOT> will look for new events (waiting if |
225 | neccessary) and will handle those and any outstanding ones. It will block |
236 | neccessary) and will handle those and any outstanding ones. It will block |
226 | your process until at least one new event arrives. |
237 | your process until at least one new event arrives, and will return after |
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238 | one iteration of the loop. |
227 | |
239 | |
228 | This flags value could be used to implement alternative looping |
240 | This flags value could be used to implement alternative looping |
229 | constructs, but the C<prepare> and C<check> watchers provide a better and |
241 | constructs, but the C<prepare> and C<check> watchers provide a better and |
230 | more generic mechanism. |
242 | more generic mechanism. |
231 | |
243 | |
232 | =item ev_unloop (loop, how) |
244 | =item ev_unloop (loop, how) |
233 | |
245 | |
234 | Can be used to make a call to C<ev_loop> return early. The C<how> argument |
246 | Can be used to make a call to C<ev_loop> return early (but only after it |
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247 | has processed all outstanding events). The C<how> argument must be either |
235 | must be either C<EVUNLOOP_ONCE>, which will make the innermost C<ev_loop> |
248 | C<EVUNLOOP_ONE>, which will make the innermost C<ev_loop> call return, or |
236 | call return, or C<EVUNLOOP_ALL>, which will make all nested C<ev_loop> |
249 | C<EVUNLOOP_ALL>, which will make all nested C<ev_loop> calls return. |
237 | calls return. |
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238 | |
250 | |
239 | =item ev_ref (loop) |
251 | =item ev_ref (loop) |
240 | |
252 | |
241 | =item ev_unref (loop) |
253 | =item ev_unref (loop) |
242 | |
254 | |
243 | Ref/unref can be used to add or remove a refcount on the event loop: Every |
255 | Ref/unref can be used to add or remove a reference count on the event |
244 | watcher keeps one reference. If you have a long-runing watcher you never |
256 | loop: Every watcher keeps one reference, and as long as the reference |
245 | unregister that should not keep ev_loop from running, ev_unref() after |
257 | count is nonzero, C<ev_loop> will not return on its own. If you have |
246 | starting, and ev_ref() before stopping it. Libev itself uses this for |
258 | a watcher you never unregister that should not keep C<ev_loop> from |
247 | example for its internal signal pipe: It is not visible to you as a user |
259 | returning, ev_unref() after starting, and ev_ref() before stopping it. For |
248 | and should not keep C<ev_loop> from exiting if the work is done. It is |
260 | example, libev itself uses this for its internal signal pipe: It is not |
249 | also an excellent way to do this for generic recurring timers or from |
261 | visible to the libev user and should not keep C<ev_loop> from exiting if |
250 | within third-party libraries. Just remember to unref after start and ref |
262 | no event watchers registered by it are active. It is also an excellent |
251 | before stop. |
263 | way to do this for generic recurring timers or from within third-party |
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264 | libraries. Just remember to I<unref after start> and I<ref before stop>. |
252 | |
265 | |
253 | =back |
266 | =back |
254 | |
267 | |
255 | =head1 ANATOMY OF A WATCHER |
268 | =head1 ANATOMY OF A WATCHER |
256 | |
269 | |
257 | A watcher is a structure that you create and register to record your |
270 | A watcher is a structure that you create and register to record your |
258 | interest in some event. For instance, if you want to wait for STDIN to |
271 | interest in some event. For instance, if you want to wait for STDIN to |
259 | become readable, you would create an ev_io watcher for that: |
272 | become readable, you would create an C<ev_io> watcher for that: |
260 | |
273 | |
261 | static void my_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
274 | static void my_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
262 | { |
275 | { |
263 | ev_io_stop (w); |
276 | ev_io_stop (w); |
264 | ev_unloop (loop, EVUNLOOP_ALL); |
277 | ev_unloop (loop, EVUNLOOP_ALL); |
… | |
… | |
293 | |
306 | |
294 | As long as your watcher is active (has been started but not stopped) you |
307 | As long as your watcher is active (has been started but not stopped) you |
295 | must not touch the values stored in it. Most specifically you must never |
308 | must not touch the values stored in it. Most specifically you must never |
296 | reinitialise it or call its set method. |
309 | reinitialise it or call its set method. |
297 | |
310 | |
298 | You cna check whether an event is active by calling the C<ev_is_active |
311 | You can check whether an event is active by calling the C<ev_is_active |
299 | (watcher *)> macro. To see whether an event is outstanding (but the |
312 | (watcher *)> macro. To see whether an event is outstanding (but the |
300 | callback for it has not been called yet) you cna use the C<ev_is_pending |
313 | callback for it has not been called yet) you can use the C<ev_is_pending |
301 | (watcher *)> macro. |
314 | (watcher *)> macro. |
302 | |
315 | |
303 | Each and every callback receives the event loop pointer as first, the |
316 | Each and every callback receives the event loop pointer as first, the |
304 | registered watcher structure as second, and a bitset of received events as |
317 | registered watcher structure as second, and a bitset of received events as |
305 | third argument. |
318 | third argument. |
306 | |
319 | |
307 | The rceeived events usually include a single bit per event type received |
320 | The received events usually include a single bit per event type received |
308 | (you can receive multiple events at the same time). The possible bit masks |
321 | (you can receive multiple events at the same time). The possible bit masks |
309 | are: |
322 | are: |
310 | |
323 | |
311 | =over 4 |
324 | =over 4 |
312 | |
325 | |
313 | =item EV_READ |
326 | =item C<EV_READ> |
314 | |
327 | |
315 | =item EV_WRITE |
328 | =item C<EV_WRITE> |
316 | |
329 | |
317 | The file descriptor in the ev_io watcher has become readable and/or |
330 | The file descriptor in the C<ev_io> watcher has become readable and/or |
318 | writable. |
331 | writable. |
319 | |
332 | |
320 | =item EV_TIMEOUT |
333 | =item C<EV_TIMEOUT> |
321 | |
334 | |
322 | The ev_timer watcher has timed out. |
335 | The C<ev_timer> watcher has timed out. |
323 | |
336 | |
324 | =item EV_PERIODIC |
337 | =item C<EV_PERIODIC> |
325 | |
338 | |
326 | The ev_periodic watcher has timed out. |
339 | The C<ev_periodic> watcher has timed out. |
327 | |
340 | |
328 | =item EV_SIGNAL |
341 | =item C<EV_SIGNAL> |
329 | |
342 | |
330 | The signal specified in the ev_signal watcher has been received by a thread. |
343 | The signal specified in the C<ev_signal> watcher has been received by a thread. |
331 | |
344 | |
332 | =item EV_CHILD |
345 | =item C<EV_CHILD> |
333 | |
346 | |
334 | The pid specified in the ev_child watcher has received a status change. |
347 | The pid specified in the C<ev_child> watcher has received a status change. |
335 | |
348 | |
336 | =item EV_IDLE |
349 | =item C<EV_IDLE> |
337 | |
350 | |
338 | The ev_idle watcher has determined that you have nothing better to do. |
351 | The C<ev_idle> watcher has determined that you have nothing better to do. |
339 | |
352 | |
340 | =item EV_PREPARE |
353 | =item C<EV_PREPARE> |
341 | |
354 | |
342 | =item EV_CHECK |
355 | =item C<EV_CHECK> |
343 | |
356 | |
344 | All ev_prepare watchers are invoked just I<before> C<ev_loop> starts |
357 | All C<ev_prepare> watchers are invoked just I<before> C<ev_loop> starts |
345 | to gather new events, and all ev_check watchers are invoked just after |
358 | to gather new events, and all C<ev_check> watchers are invoked just after |
346 | C<ev_loop> has gathered them, but before it invokes any callbacks for any |
359 | C<ev_loop> has gathered them, but before it invokes any callbacks for any |
347 | received events. Callbacks of both watcher types can start and stop as |
360 | received events. Callbacks of both watcher types can start and stop as |
348 | many watchers as they want, and all of them will be taken into account |
361 | many watchers as they want, and all of them will be taken into account |
349 | (for example, a ev_prepare watcher might start an idle watcher to keep |
362 | (for example, a C<ev_prepare> watcher might start an idle watcher to keep |
350 | C<ev_loop> from blocking). |
363 | C<ev_loop> from blocking). |
351 | |
364 | |
352 | =item EV_ERROR |
365 | =item C<EV_ERROR> |
353 | |
366 | |
354 | An unspecified error has occured, the watcher has been stopped. This might |
367 | An unspecified error has occured, the watcher has been stopped. This might |
355 | happen because the watcher could not be properly started because libev |
368 | happen because the watcher could not be properly started because libev |
356 | ran out of memory, a file descriptor was found to be closed or any other |
369 | ran out of memory, a file descriptor was found to be closed or any other |
357 | problem. You best act on it by reporting the problem and somehow coping |
370 | problem. You best act on it by reporting the problem and somehow coping |
… | |
… | |
366 | =back |
379 | =back |
367 | |
380 | |
368 | =head2 ASSOCIATING CUSTOM DATA WITH A WATCHER |
381 | =head2 ASSOCIATING CUSTOM DATA WITH A WATCHER |
369 | |
382 | |
370 | Each watcher has, by default, a member C<void *data> that you can change |
383 | Each watcher has, by default, a member C<void *data> that you can change |
371 | and read at any time, libev will completely ignore it. This cna be used |
384 | and read at any time, libev will completely ignore it. This can be used |
372 | to associate arbitrary data with your watcher. If you need more data and |
385 | to associate arbitrary data with your watcher. If you need more data and |
373 | don't want to allocate memory and store a pointer to it in that data |
386 | don't want to allocate memory and store a pointer to it in that data |
374 | member, you can also "subclass" the watcher type and provide your own |
387 | member, you can also "subclass" the watcher type and provide your own |
375 | data: |
388 | data: |
376 | |
389 | |
… | |
… | |
398 | =head1 WATCHER TYPES |
411 | =head1 WATCHER TYPES |
399 | |
412 | |
400 | This section describes each watcher in detail, but will not repeat |
413 | This section describes each watcher in detail, but will not repeat |
401 | information given in the last section. |
414 | information given in the last section. |
402 | |
415 | |
403 | =head2 struct ev_io - is my file descriptor readable or writable |
416 | =head2 C<ev_io> - is this file descriptor readable or writable |
404 | |
417 | |
405 | I/O watchers check whether a file descriptor is readable or writable |
418 | I/O watchers check whether a file descriptor is readable or writable |
406 | in each iteration of the event loop (This behaviour is called |
419 | in each iteration of the event loop (This behaviour is called |
407 | level-triggering because you keep receiving events as long as the |
420 | level-triggering because you keep receiving events as long as the |
408 | condition persists. Remember you cna stop the watcher if you don't want to |
421 | condition persists. Remember you can stop the watcher if you don't want to |
409 | act on the event and neither want to receive future events). |
422 | act on the event and neither want to receive future events). |
410 | |
423 | |
|
|
424 | In general you can register as many read and/or write event watchers per |
|
|
425 | fd as you want (as long as you don't confuse yourself). Setting all file |
|
|
426 | descriptors to non-blocking mode is also usually a good idea (but not |
|
|
427 | required if you know what you are doing). |
|
|
428 | |
|
|
429 | You have to be careful with dup'ed file descriptors, though. Some backends |
|
|
430 | (the linux epoll backend is a notable example) cannot handle dup'ed file |
|
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431 | descriptors correctly if you register interest in two or more fds pointing |
|
|
432 | to the same underlying file/socket etc. description (that is, they share |
|
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433 | the same underlying "file open"). |
|
|
434 | |
|
|
435 | If you must do this, then force the use of a known-to-be-good backend |
|
|
436 | (at the time of this writing, this includes only EVMETHOD_SELECT and |
|
|
437 | EVMETHOD_POLL). |
|
|
438 | |
411 | =over 4 |
439 | =over 4 |
412 | |
440 | |
413 | =item ev_io_init (ev_io *, callback, int fd, int events) |
441 | =item ev_io_init (ev_io *, callback, int fd, int events) |
414 | |
442 | |
415 | =item ev_io_set (ev_io *, int fd, int events) |
443 | =item ev_io_set (ev_io *, int fd, int events) |
416 | |
444 | |
417 | Configures an ev_io watcher. The fd is the file descriptor to rceeive |
445 | Configures an C<ev_io> watcher. The fd is the file descriptor to rceeive |
418 | events for and events is either C<EV_READ>, C<EV_WRITE> or C<EV_READ | |
446 | events for and events is either C<EV_READ>, C<EV_WRITE> or C<EV_READ | |
419 | EV_WRITE> to receive the given events. |
447 | EV_WRITE> to receive the given events. |
420 | |
448 | |
421 | =back |
449 | =back |
422 | |
450 | |
423 | =head2 struct ev_timer - relative and optionally recurring timeouts |
451 | =head2 C<ev_timer> - relative and optionally recurring timeouts |
424 | |
452 | |
425 | Timer watchers are simple relative timers that generate an event after a |
453 | Timer watchers are simple relative timers that generate an event after a |
426 | given time, and optionally repeating in regular intervals after that. |
454 | given time, and optionally repeating in regular intervals after that. |
427 | |
455 | |
428 | The timers are based on real time, that is, if you register an event that |
456 | The timers are based on real time, that is, if you register an event that |
429 | times out after an hour and youreset your system clock to last years |
457 | times out after an hour and you reset your system clock to last years |
430 | time, it will still time out after (roughly) and hour. "Roughly" because |
458 | time, it will still time out after (roughly) and hour. "Roughly" because |
431 | detecting time jumps is hard, and soem inaccuracies are unavoidable (the |
459 | detecting time jumps is hard, and soem inaccuracies are unavoidable (the |
432 | monotonic clock option helps a lot here). |
460 | monotonic clock option helps a lot here). |
|
|
461 | |
|
|
462 | The relative timeouts are calculated relative to the C<ev_now ()> |
|
|
463 | time. This is usually the right thing as this timestamp refers to the time |
|
|
464 | of the event triggering whatever timeout you are modifying/starting. If |
|
|
465 | you suspect event processing to be delayed and you *need* to base the timeout |
|
|
466 | on the current time, use something like this to adjust for this: |
|
|
467 | |
|
|
468 | ev_timer_set (&timer, after + ev_now () - ev_time (), 0.); |
433 | |
469 | |
434 | =over 4 |
470 | =over 4 |
435 | |
471 | |
436 | =item ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat) |
472 | =item ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat) |
437 | |
473 | |
… | |
… | |
443 | later, again, and again, until stopped manually. |
479 | later, again, and again, until stopped manually. |
444 | |
480 | |
445 | The timer itself will do a best-effort at avoiding drift, that is, if you |
481 | The timer itself will do a best-effort at avoiding drift, that is, if you |
446 | configure a timer to trigger every 10 seconds, then it will trigger at |
482 | configure a timer to trigger every 10 seconds, then it will trigger at |
447 | exactly 10 second intervals. If, however, your program cannot keep up with |
483 | exactly 10 second intervals. If, however, your program cannot keep up with |
448 | the timer (ecause it takes longer than those 10 seconds to do stuff) the |
484 | the timer (because it takes longer than those 10 seconds to do stuff) the |
449 | timer will not fire more than once per event loop iteration. |
485 | timer will not fire more than once per event loop iteration. |
450 | |
486 | |
451 | =item ev_timer_again (loop) |
487 | =item ev_timer_again (loop) |
452 | |
488 | |
453 | This will act as if the timer timed out and restart it again if it is |
489 | This will act as if the timer timed out and restart it again if it is |
… | |
… | |
460 | |
496 | |
461 | This sounds a bit complicated, but here is a useful and typical |
497 | This sounds a bit complicated, but here is a useful and typical |
462 | example: Imagine you have a tcp connection and you want a so-called idle |
498 | example: Imagine you have a tcp connection and you want a so-called idle |
463 | timeout, that is, you want to be called when there have been, say, 60 |
499 | timeout, that is, you want to be called when there have been, say, 60 |
464 | seconds of inactivity on the socket. The easiest way to do this is to |
500 | seconds of inactivity on the socket. The easiest way to do this is to |
465 | configure an ev_timer with after=repeat=60 and calling ev_timer_again each |
501 | configure an C<ev_timer> with after=repeat=60 and calling ev_timer_again each |
466 | time you successfully read or write some data. If you go into an idle |
502 | time you successfully read or write some data. If you go into an idle |
467 | state where you do not expect data to travel on the socket, you can stop |
503 | state where you do not expect data to travel on the socket, you can stop |
468 | the timer, and again will automatically restart it if need be. |
504 | the timer, and again will automatically restart it if need be. |
469 | |
505 | |
470 | =back |
506 | =back |
471 | |
507 | |
472 | =head2 ev_periodic - to cron or not to cron it |
508 | =head2 C<ev_periodic> - to cron or not to cron |
473 | |
509 | |
474 | Periodic watchers are also timers of a kind, but they are very versatile |
510 | Periodic watchers are also timers of a kind, but they are very versatile |
475 | (and unfortunately a bit complex). |
511 | (and unfortunately a bit complex). |
476 | |
512 | |
477 | Unlike ev_timer's, they are not based on real time (or relative time) |
513 | Unlike C<ev_timer>'s, they are not based on real time (or relative time) |
478 | but on wallclock time (absolute time). You can tell a periodic watcher |
514 | but on wallclock time (absolute time). You can tell a periodic watcher |
479 | to trigger "at" some specific point in time. For example, if you tell a |
515 | to trigger "at" some specific point in time. For example, if you tell a |
480 | periodic watcher to trigger in 10 seconds (by specifiying e.g. c<ev_now () |
516 | periodic watcher to trigger in 10 seconds (by specifiying e.g. c<ev_now () |
481 | + 10.>) and then reset your system clock to the last year, then it will |
517 | + 10.>) and then reset your system clock to the last year, then it will |
482 | take a year to trigger the event (unlike an ev_timer, which would trigger |
518 | take a year to trigger the event (unlike an C<ev_timer>, which would trigger |
483 | roughly 10 seconds later and of course not if you reset your system time |
519 | roughly 10 seconds later and of course not if you reset your system time |
484 | again). |
520 | again). |
485 | |
521 | |
486 | They can also be used to implement vastly more complex timers, such as |
522 | They can also be used to implement vastly more complex timers, such as |
487 | triggering an event on eahc midnight, local time. |
523 | triggering an event on eahc midnight, local time. |
… | |
… | |
516 | |
552 | |
517 | ev_periodic_set (&periodic, 0., 3600., 0); |
553 | ev_periodic_set (&periodic, 0., 3600., 0); |
518 | |
554 | |
519 | This doesn't mean there will always be 3600 seconds in between triggers, |
555 | This doesn't mean there will always be 3600 seconds in between triggers, |
520 | but only that the the callback will be called when the system time shows a |
556 | but only that the the callback will be called when the system time shows a |
521 | full hour (UTC), or more correct, when the system time is evenly divisible |
557 | full hour (UTC), or more correctly, when the system time is evenly divisible |
522 | by 3600. |
558 | by 3600. |
523 | |
559 | |
524 | Another way to think about it (for the mathematically inclined) is that |
560 | Another way to think about it (for the mathematically inclined) is that |
525 | ev_periodic will try to run the callback in this mode at the next possible |
561 | C<ev_periodic> will try to run the callback in this mode at the next possible |
526 | time where C<time = at (mod interval)>, regardless of any time jumps. |
562 | time where C<time = at (mod interval)>, regardless of any time jumps. |
527 | |
563 | |
528 | =item * manual reschedule mode (reschedule_cb = callback) |
564 | =item * manual reschedule mode (reschedule_cb = callback) |
529 | |
565 | |
530 | In this mode the values for C<interval> and C<at> are both being |
566 | In this mode the values for C<interval> and C<at> are both being |
531 | ignored. Instead, each time the periodic watcher gets scheduled, the |
567 | ignored. Instead, each time the periodic watcher gets scheduled, the |
532 | reschedule callback will be called with the watcher as first, and the |
568 | reschedule callback will be called with the watcher as first, and the |
533 | current time as second argument. |
569 | current time as second argument. |
534 | |
570 | |
535 | NOTE: I<This callback MUST NOT stop or destroy the periodic or any other |
571 | NOTE: I<This callback MUST NOT stop or destroy any periodic watcher, |
536 | periodic watcher, ever, or make any event loop modificstions>. If you need |
572 | ever, or make any event loop modifications>. If you need to stop it, |
537 | to stop it, return 1e30 (or so, fudge fudge) and stop it afterwards. |
573 | return C<now + 1e30> (or so, fudge fudge) and stop it afterwards (e.g. by |
|
|
574 | starting a prepare watcher). |
538 | |
575 | |
539 | Its prototype is c<ev_tstamp (*reschedule_cb)(struct ev_periodic *w, |
576 | Its prototype is C<ev_tstamp (*reschedule_cb)(struct ev_periodic *w, |
540 | ev_tstamp now)>, e.g.: |
577 | ev_tstamp now)>, e.g.: |
541 | |
578 | |
542 | static ev_tstamp my_rescheduler (struct ev_periodic *w, ev_tstamp now) |
579 | static ev_tstamp my_rescheduler (struct ev_periodic *w, ev_tstamp now) |
543 | { |
580 | { |
544 | return now + 60.; |
581 | return now + 60.; |
… | |
… | |
547 | It must return the next time to trigger, based on the passed time value |
584 | It must return the next time to trigger, based on the passed time value |
548 | (that is, the lowest time value larger than to the second argument). It |
585 | (that is, the lowest time value larger than to the second argument). It |
549 | will usually be called just before the callback will be triggered, but |
586 | will usually be called just before the callback will be triggered, but |
550 | might be called at other times, too. |
587 | might be called at other times, too. |
551 | |
588 | |
|
|
589 | NOTE: I<< This callback must always return a time that is later than the |
|
|
590 | passed C<now> value >>. Not even C<now> itself will do, it I<must> be larger. |
|
|
591 | |
552 | This can be used to create very complex timers, such as a timer that |
592 | This can be used to create very complex timers, such as a timer that |
553 | triggers on each midnight, local time. To do this, you would calculate the |
593 | triggers on each midnight, local time. To do this, you would calculate the |
554 | next midnight after C<now> and return the timestamp value for this. How you do this |
594 | next midnight after C<now> and return the timestamp value for this. How |
555 | is, again, up to you (but it is not trivial). |
595 | you do this is, again, up to you (but it is not trivial, which is the main |
|
|
596 | reason I omitted it as an example). |
556 | |
597 | |
557 | =back |
598 | =back |
558 | |
599 | |
559 | =item ev_periodic_again (loop, ev_periodic *) |
600 | =item ev_periodic_again (loop, ev_periodic *) |
560 | |
601 | |
… | |
… | |
563 | a different time than the last time it was called (e.g. in a crond like |
604 | a different time than the last time it was called (e.g. in a crond like |
564 | program when the crontabs have changed). |
605 | program when the crontabs have changed). |
565 | |
606 | |
566 | =back |
607 | =back |
567 | |
608 | |
568 | =head2 ev_signal - signal me when a signal gets signalled |
609 | =head2 C<ev_signal> - signal me when a signal gets signalled |
569 | |
610 | |
570 | Signal watchers will trigger an event when the process receives a specific |
611 | Signal watchers will trigger an event when the process receives a specific |
571 | signal one or more times. Even though signals are very asynchronous, libev |
612 | signal one or more times. Even though signals are very asynchronous, libev |
572 | will try its best to deliver signals synchronously, i.e. as part of the |
613 | will try it's best to deliver signals synchronously, i.e. as part of the |
573 | normal event processing, like any other event. |
614 | normal event processing, like any other event. |
574 | |
615 | |
575 | You cna configure as many watchers as you like per signal. Only when the |
616 | You can configure as many watchers as you like per signal. Only when the |
576 | first watcher gets started will libev actually register a signal watcher |
617 | first watcher gets started will libev actually register a signal watcher |
577 | with the kernel (thus it coexists with your own signal handlers as long |
618 | with the kernel (thus it coexists with your own signal handlers as long |
578 | as you don't register any with libev). Similarly, when the last signal |
619 | as you don't register any with libev). Similarly, when the last signal |
579 | watcher for a signal is stopped libev will reset the signal handler to |
620 | watcher for a signal is stopped libev will reset the signal handler to |
580 | SIG_DFL (regardless of what it was set to before). |
621 | SIG_DFL (regardless of what it was set to before). |
… | |
… | |
588 | Configures the watcher to trigger on the given signal number (usually one |
629 | Configures the watcher to trigger on the given signal number (usually one |
589 | of the C<SIGxxx> constants). |
630 | of the C<SIGxxx> constants). |
590 | |
631 | |
591 | =back |
632 | =back |
592 | |
633 | |
593 | =head2 ev_child - wait for pid status changes |
634 | =head2 C<ev_child> - wait for pid status changes |
594 | |
635 | |
595 | Child watchers trigger when your process receives a SIGCHLD in response to |
636 | Child watchers trigger when your process receives a SIGCHLD in response to |
596 | some child status changes (most typically when a child of yours dies). |
637 | some child status changes (most typically when a child of yours dies). |
597 | |
638 | |
598 | =over 4 |
639 | =over 4 |
… | |
… | |
602 | =item ev_child_set (ev_child *, int pid) |
643 | =item ev_child_set (ev_child *, int pid) |
603 | |
644 | |
604 | Configures the watcher to wait for status changes of process C<pid> (or |
645 | Configures the watcher to wait for status changes of process C<pid> (or |
605 | I<any> process if C<pid> is specified as C<0>). The callback can look |
646 | I<any> process if C<pid> is specified as C<0>). The callback can look |
606 | at the C<rstatus> member of the C<ev_child> watcher structure to see |
647 | at the C<rstatus> member of the C<ev_child> watcher structure to see |
607 | the status word (use the macros from C<sys/wait.h>). The C<rpid> member |
648 | the status word (use the macros from C<sys/wait.h> and see your systems |
608 | contains the pid of the process causing the status change. |
649 | C<waitpid> documentation). The C<rpid> member contains the pid of the |
|
|
650 | process causing the status change. |
609 | |
651 | |
610 | =back |
652 | =back |
611 | |
653 | |
612 | =head2 ev_idle - when you've got nothing better to do |
654 | =head2 C<ev_idle> - when you've got nothing better to do |
613 | |
655 | |
614 | Idle watchers trigger events when there are no other I/O or timer (or |
656 | Idle watchers trigger events when there are no other events are pending |
615 | periodic) events pending. That is, as long as your process is busy |
657 | (prepare, check and other idle watchers do not count). That is, as long |
616 | handling sockets or timeouts it will not be called. But when your process |
658 | as your process is busy handling sockets or timeouts (or even signals, |
617 | is idle all idle watchers are being called again and again - until |
659 | imagine) it will not be triggered. But when your process is idle all idle |
|
|
660 | watchers are being called again and again, once per event loop iteration - |
618 | stopped, that is, or your process receives more events. |
661 | until stopped, that is, or your process receives more events and becomes |
|
|
662 | busy. |
619 | |
663 | |
620 | The most noteworthy effect is that as long as any idle watchers are |
664 | The most noteworthy effect is that as long as any idle watchers are |
621 | active, the process will not block when waiting for new events. |
665 | active, the process will not block when waiting for new events. |
622 | |
666 | |
623 | Apart from keeping your process non-blocking (which is a useful |
667 | Apart from keeping your process non-blocking (which is a useful |
… | |
… | |
633 | kind. There is a C<ev_idle_set> macro, but using it is utterly pointless, |
677 | kind. There is a C<ev_idle_set> macro, but using it is utterly pointless, |
634 | believe me. |
678 | believe me. |
635 | |
679 | |
636 | =back |
680 | =back |
637 | |
681 | |
638 | =head2 prepare and check - your hooks into the event loop |
682 | =head2 C<ev_prepare> and C<ev_check> - customise your event loop |
639 | |
683 | |
640 | Prepare and check watchers usually (but not always) are used in |
684 | Prepare and check watchers are usually (but not always) used in tandem: |
641 | tandom. Prepare watchers get invoked before the process blocks and check |
685 | prepare watchers get invoked before the process blocks and check watchers |
642 | watchers afterwards. |
686 | afterwards. |
643 | |
687 | |
644 | Their main purpose is to integrate other event mechanisms into libev. This |
688 | Their main purpose is to integrate other event mechanisms into libev. This |
645 | could be used, for example, to track variable changes, implement your own |
689 | could be used, for example, to track variable changes, implement your own |
646 | watchers, integrate net-snmp or a coroutine library and lots more. |
690 | watchers, integrate net-snmp or a coroutine library and lots more. |
647 | |
691 | |
648 | This is done by examining in each prepare call which file descriptors need |
692 | This is done by examining in each prepare call which file descriptors need |
649 | to be watched by the other library, registering ev_io watchers for them |
693 | to be watched by the other library, registering C<ev_io> watchers for |
650 | and starting an ev_timer watcher for any timeouts (many libraries provide |
694 | them and starting an C<ev_timer> watcher for any timeouts (many libraries |
651 | just this functionality). Then, in the check watcher you check for any |
695 | provide just this functionality). Then, in the check watcher you check for |
652 | events that occured (by making your callbacks set soem flags for example) |
696 | any events that occured (by checking the pending status of all watchers |
653 | and call back into the library. |
697 | and stopping them) and call back into the library. The I/O and timer |
|
|
698 | callbacks will never actually be called (but must be valid nevertheless, |
|
|
699 | because you never know, you know?). |
654 | |
700 | |
655 | As another example, the perl Coro module uses these hooks to integrate |
701 | As another example, the Perl Coro module uses these hooks to integrate |
656 | coroutines into libev programs, by yielding to other active coroutines |
702 | coroutines into libev programs, by yielding to other active coroutines |
657 | during each prepare and only letting the process block if no coroutines |
703 | during each prepare and only letting the process block if no coroutines |
658 | are ready to run. |
704 | are ready to run (it's actually more complicated: it only runs coroutines |
|
|
705 | with priority higher than or equal to the event loop and one coroutine |
|
|
706 | of lower priority, but only once, using idle watchers to keep the event |
|
|
707 | loop from blocking if lower-priority coroutines are active, thus mapping |
|
|
708 | low-priority coroutines to idle/background tasks). |
659 | |
709 | |
660 | =over 4 |
710 | =over 4 |
661 | |
711 | |
662 | =item ev_prepare_init (ev_prepare *, callback) |
712 | =item ev_prepare_init (ev_prepare *, callback) |
663 | |
713 | |
664 | =item ev_check_init (ev_check *, callback) |
714 | =item ev_check_init (ev_check *, callback) |
665 | |
715 | |
666 | Initialises and configures the prepare or check watcher - they have no |
716 | Initialises and configures the prepare or check watcher - they have no |
667 | parameters of any kind. There are C<ev_prepare_set> and C<ev_check_set> |
717 | parameters of any kind. There are C<ev_prepare_set> and C<ev_check_set> |
668 | macros, but using them is utterly, utterly pointless. |
718 | macros, but using them is utterly, utterly and completely pointless. |
669 | |
719 | |
670 | =back |
720 | =back |
671 | |
721 | |
672 | =head1 OTHER FUNCTIONS |
722 | =head1 OTHER FUNCTIONS |
673 | |
723 | |
674 | There are some other fucntions of possible interest. Described. Here. Now. |
724 | There are some other functions of possible interest. Described. Here. Now. |
675 | |
725 | |
676 | =over 4 |
726 | =over 4 |
677 | |
727 | |
678 | =item ev_once (loop, int fd, int events, ev_tstamp timeout, callback) |
728 | =item ev_once (loop, int fd, int events, ev_tstamp timeout, callback) |
679 | |
729 | |
680 | This function combines a simple timer and an I/O watcher, calls your |
730 | This function combines a simple timer and an I/O watcher, calls your |
681 | callback on whichever event happens first and automatically stop both |
731 | callback on whichever event happens first and automatically stop both |
682 | watchers. This is useful if you want to wait for a single event on an fd |
732 | watchers. This is useful if you want to wait for a single event on an fd |
683 | or timeout without havign to allocate/configure/start/stop/free one or |
733 | or timeout without having to allocate/configure/start/stop/free one or |
684 | more watchers yourself. |
734 | more watchers yourself. |
685 | |
735 | |
686 | If C<fd> is less than 0, then no I/O watcher will be started and events is |
736 | If C<fd> is less than 0, then no I/O watcher will be started and events |
687 | ignored. Otherwise, an ev_io watcher for the given C<fd> and C<events> set |
737 | is being ignored. Otherwise, an C<ev_io> watcher for the given C<fd> and |
688 | will be craeted and started. |
738 | C<events> set will be craeted and started. |
689 | |
739 | |
690 | If C<timeout> is less than 0, then no timeout watcher will be |
740 | If C<timeout> is less than 0, then no timeout watcher will be |
691 | started. Otherwise an ev_timer watcher with after = C<timeout> (and repeat |
741 | started. Otherwise an C<ev_timer> watcher with after = C<timeout> (and |
692 | = 0) will be started. |
742 | repeat = 0) will be started. While C<0> is a valid timeout, it is of |
|
|
743 | dubious value. |
693 | |
744 | |
694 | The callback has the type C<void (*cb)(int revents, void *arg)> and |
745 | The callback has the type C<void (*cb)(int revents, void *arg)> and gets |
695 | gets passed an events set (normally a combination of EV_ERROR, EV_READ, |
746 | passed an C<revents> set like normal event callbacks (a combination of |
696 | EV_WRITE or EV_TIMEOUT) and the C<arg> value passed to C<ev_once>: |
747 | C<EV_ERROR>, C<EV_READ>, C<EV_WRITE> or C<EV_TIMEOUT>) and the C<arg> |
|
|
748 | value passed to C<ev_once>: |
697 | |
749 | |
698 | static void stdin_ready (int revents, void *arg) |
750 | static void stdin_ready (int revents, void *arg) |
699 | { |
751 | { |
700 | if (revents & EV_TIMEOUT) |
752 | if (revents & EV_TIMEOUT) |
701 | /* doh, nothing entered */ |
753 | /* doh, nothing entered */; |
702 | else if (revents & EV_READ) |
754 | else if (revents & EV_READ) |
703 | /* stdin might have data for us, joy! */ |
755 | /* stdin might have data for us, joy! */; |
704 | } |
756 | } |
705 | |
757 | |
706 | ev_once (STDIN_FILENO, EV_READm 10., stdin_ready, 0); |
758 | ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0); |
707 | |
759 | |
708 | =item ev_feed_event (loop, watcher, int events) |
760 | =item ev_feed_event (loop, watcher, int events) |
709 | |
761 | |
710 | Feeds the given event set into the event loop, as if the specified event |
762 | Feeds the given event set into the event loop, as if the specified event |
711 | has happened for the specified watcher (which must be a pointer to an |
763 | had happened for the specified watcher (which must be a pointer to an |
712 | initialised but not necessarily active event watcher). |
764 | initialised but not necessarily started event watcher). |
713 | |
765 | |
714 | =item ev_feed_fd_event (loop, int fd, int revents) |
766 | =item ev_feed_fd_event (loop, int fd, int revents) |
715 | |
767 | |
716 | Feed an event on the given fd, as if a file descriptor backend detected it. |
768 | Feed an event on the given fd, as if a file descriptor backend detected |
|
|
769 | the given events it. |
717 | |
770 | |
718 | =item ev_feed_signal_event (loop, int signum) |
771 | =item ev_feed_signal_event (loop, int signum) |
719 | |
772 | |
720 | Feed an event as if the given signal occured (loop must be the default loop!). |
773 | Feed an event as if the given signal occured (loop must be the default loop!). |
721 | |
774 | |
722 | =back |
775 | =back |
723 | |
776 | |
|
|
777 | =head1 LIBEVENT EMULATION |
|
|
778 | |
|
|
779 | Libev offers a compatibility emulation layer for libevent. It cannot |
|
|
780 | emulate the internals of libevent, so here are some usage hints: |
|
|
781 | |
|
|
782 | =over 4 |
|
|
783 | |
|
|
784 | =item * Use it by including <event.h>, as usual. |
|
|
785 | |
|
|
786 | =item * The following members are fully supported: ev_base, ev_callback, |
|
|
787 | ev_arg, ev_fd, ev_res, ev_events. |
|
|
788 | |
|
|
789 | =item * Avoid using ev_flags and the EVLIST_*-macros, while it is |
|
|
790 | maintained by libev, it does not work exactly the same way as in libevent (consider |
|
|
791 | it a private API). |
|
|
792 | |
|
|
793 | =item * Priorities are not currently supported. Initialising priorities |
|
|
794 | will fail and all watchers will have the same priority, even though there |
|
|
795 | is an ev_pri field. |
|
|
796 | |
|
|
797 | =item * Other members are not supported. |
|
|
798 | |
|
|
799 | =item * The libev emulation is I<not> ABI compatible to libevent, you need |
|
|
800 | to use the libev header file and library. |
|
|
801 | |
|
|
802 | =back |
|
|
803 | |
|
|
804 | =head1 C++ SUPPORT |
|
|
805 | |
|
|
806 | TBD. |
|
|
807 | |
724 | =head1 AUTHOR |
808 | =head1 AUTHOR |
725 | |
809 | |
726 | Marc Lehmann <libev@schmorp.de>. |
810 | Marc Lehmann <libev@schmorp.de>. |
727 | |
811 | |