… | |
… | |
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). It also is quite |
30 | loop mechanism itself (idle, prepare and check watchers). It also is quite |
31 | fast (see a L<http://libev.schmorp.de/bench.html|benchmark> comparing it |
31 | fast (see this L<benchmark|http://libev.schmorp.de/bench.html> comparing |
32 | to libevent). |
32 | it to libevent for example). |
33 | |
33 | |
34 | =head1 CONVENTIONS |
34 | =head1 CONVENTIONS |
35 | |
35 | |
36 | Libev is very configurable. In this manual the default configuration |
36 | Libev is very configurable. In this manual the default configuration |
37 | will be described, which supports multiple event loops. For more info |
37 | will be described, which supports multiple event loops. For more info |
38 | about various configuraiton options please have a look at the file |
38 | about various configuration options please have a look at the file |
39 | 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 |
40 | support for multiple event loops, then all functions taking an initial |
40 | support for multiple event loops, then all functions taking an initial |
41 | 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 *>) |
42 | will not have this argument. |
42 | will not have this argument. |
43 | |
43 | |
44 | =head1 TIME AND OTHER GLOBAL FUNCTIONS |
44 | =head1 TIME REPRESENTATION |
45 | |
45 | |
46 | Libev represents time as a single floating point number, representing the |
46 | Libev represents time as a single floating point number, representing the |
47 | (fractional) number of seconds since the (POSIX) epoch (somewhere near |
47 | (fractional) number of seconds since the (POSIX) epoch (somewhere near |
48 | 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 |
49 | 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 |
50 | to the double type in C. |
50 | to the double type in C. |
51 | |
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 | |
52 | =over 4 |
57 | =over 4 |
53 | |
58 | |
54 | =item ev_tstamp ev_time () |
59 | =item ev_tstamp ev_time () |
55 | |
60 | |
56 | 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. |
57 | |
64 | |
58 | =item int ev_version_major () |
65 | =item int ev_version_major () |
59 | |
66 | |
60 | =item int ev_version_minor () |
67 | =item int ev_version_minor () |
61 | |
68 | |
… | |
… | |
63 | 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 |
64 | 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 |
65 | 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 |
66 | version of the library your program was compiled against. |
73 | version of the library your program was compiled against. |
67 | |
74 | |
68 | 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, |
69 | as this indicates an incompatible change. Minor versions are usually |
76 | as this indicates an incompatible change. Minor versions are usually |
70 | 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 |
71 | not a problem. |
78 | not a problem. |
72 | |
79 | |
73 | =item ev_set_allocator (void *(*cb)(void *ptr, long size)) |
80 | =item ev_set_allocator (void *(*cb)(void *ptr, long size)) |
74 | |
81 | |
75 | 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 |
76 | 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 |
77 | 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 |
78 | might abort or take some potentially destructive action. The default is |
85 | needs to be allocated, the library might abort or take some potentially |
79 | your system realloc function. |
86 | destructive action. The default is your system realloc function. |
80 | |
87 | |
81 | You could override this function in high-availability programs to, say, |
88 | You could override this function in high-availability programs to, say, |
82 | 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, |
83 | 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. |
84 | |
91 | |
… | |
… | |
86 | |
93 | |
87 | 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 |
88 | 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 |
89 | indicating the system call or subsystem causing the problem. If this |
96 | indicating the system call or subsystem causing the problem. If this |
90 | 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 |
91 | 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 |
92 | 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 |
93 | (such as abort). |
100 | (such as abort). |
94 | |
101 | |
95 | =back |
102 | =back |
96 | |
103 | |
… | |
… | |
99 | 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 |
100 | 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 |
101 | events, and dynamically created loops which do not. |
108 | events, and dynamically created loops which do not. |
102 | |
109 | |
103 | 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 |
104 | 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 |
105 | 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 |
106 | 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 |
107 | 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). |
108 | |
116 | |
109 | =over 4 |
117 | =over 4 |
110 | |
118 | |
111 | =item struct ev_loop *ev_default_loop (unsigned int flags) |
119 | =item struct ev_loop *ev_default_loop (unsigned int flags) |
112 | |
120 | |
… | |
… | |
117 | |
125 | |
118 | 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 |
119 | function. |
127 | function. |
120 | |
128 | |
121 | 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 |
122 | 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). |
123 | |
131 | |
124 | It supports the following flags: |
132 | It supports the following flags: |
125 | |
133 | |
126 | =over 4 |
134 | =over 4 |
127 | |
135 | |
128 | =item EVFLAG_AUTO |
136 | =item C<EVFLAG_AUTO> |
129 | |
137 | |
130 | 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 |
131 | thing, believe me). |
139 | thing, believe me). |
132 | |
140 | |
133 | =item EVFLAG_NOENV |
141 | =item C<EVFLAG_NOENV> |
134 | |
142 | |
135 | 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 |
136 | at the environment variable C<LIBEV_FLAGS>. Otherwise (the default), this |
144 | or setgid) then libev will I<not> look at the environment variable |
137 | 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 |
138 | 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 |
139 | bugs. |
148 | around bugs. |
140 | |
149 | |
141 | =item EVMETHOD_SELECT portable select backend |
150 | =item C<EVMETHOD_SELECT> (portable select backend) |
142 | |
151 | |
143 | =item EVMETHOD_POLL poll backend (everywhere except windows) |
152 | =item C<EVMETHOD_POLL> (poll backend, available everywhere except on windows) |
144 | |
153 | |
145 | =item EVMETHOD_EPOLL linux only |
154 | =item C<EVMETHOD_EPOLL> (linux only) |
146 | |
155 | |
147 | =item EVMETHOD_KQUEUE some bsds only |
156 | =item C<EVMETHOD_KQUEUE> (some bsds only) |
148 | |
157 | |
149 | =item EVMETHOD_DEVPOLL solaris 8 only |
158 | =item C<EVMETHOD_DEVPOLL> (solaris 8 only) |
150 | |
159 | |
151 | =item EVMETHOD_PORT solaris 10 only |
160 | =item C<EVMETHOD_PORT> (solaris 10 only) |
152 | |
161 | |
153 | 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 |
154 | 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 |
155 | specified, any backend will do. |
164 | specified, any backend will do. |
156 | |
165 | |
… | |
… | |
165 | |
174 | |
166 | =item ev_default_destroy () |
175 | =item ev_default_destroy () |
167 | |
176 | |
168 | Destroys the default loop again (frees all memory and kernel state |
177 | Destroys the default loop again (frees all memory and kernel state |
169 | 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 |
170 | any way whatsoever, although you cnanot rely on this :). |
179 | any way whatsoever, although you cannot rely on this :). |
171 | |
180 | |
172 | =item ev_loop_destroy (loop) |
181 | =item ev_loop_destroy (loop) |
173 | |
182 | |
174 | 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 |
175 | earlier call to C<ev_loop_new>. |
184 | earlier call to C<ev_loop_new>. |
… | |
… | |
183 | |
192 | |
184 | 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 |
185 | 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 |
186 | have to call it. |
195 | have to call it. |
187 | |
196 | |
188 | 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 |
189 | 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 |
190 | quite nicely into a call to C<pthread_atfork>: |
199 | quite nicely into a call to C<pthread_atfork>: |
191 | |
200 | |
192 | pthread_atfork (0, 0, ev_default_fork); |
201 | pthread_atfork (0, 0, ev_default_fork); |
193 | |
202 | |
… | |
… | |
200 | =item unsigned int ev_method (loop) |
209 | =item unsigned int ev_method (loop) |
201 | |
210 | |
202 | 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 |
203 | use. |
212 | use. |
204 | |
213 | |
205 | =item ev_tstamp = ev_now (loop) |
214 | =item ev_tstamp ev_now (loop) |
206 | |
215 | |
207 | 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 |
208 | got events and started processing them. This timestamp does not change |
217 | got events and started processing them. This timestamp does not change |
209 | 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 |
210 | 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 |
… | |
… | |
219 | 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 |
220 | 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. |
221 | |
230 | |
222 | 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 |
223 | 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 |
224 | case there are no events. |
233 | case there are no events and will return after one iteration of the loop. |
225 | |
234 | |
226 | 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 |
227 | 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 |
228 | 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. |
229 | |
239 | |
230 | This flags value could be used to implement alternative looping |
240 | This flags value could be used to implement alternative looping |
231 | 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 |
232 | more generic mechanism. |
242 | more generic mechanism. |
233 | |
243 | |
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244 | Here are the gory details of what ev_loop does: |
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245 | |
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246 | 1. If there are no active watchers (reference count is zero), return. |
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247 | 2. Queue and immediately call all prepare watchers. |
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248 | 3. If we have been forked, recreate the kernel state. |
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249 | 4. Update the kernel state with all outstanding changes. |
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250 | 5. Update the "event loop time". |
|
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251 | 6. Calculate for how long to block. |
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252 | 7. Block the process, waiting for events. |
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253 | 8. Update the "event loop time" and do time jump handling. |
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254 | 9. Queue all outstanding timers. |
|
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255 | 10. Queue all outstanding periodics. |
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256 | 11. If no events are pending now, queue all idle watchers. |
|
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257 | 12. Queue all check watchers. |
|
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258 | 13. Call all queued watchers in reverse order (i.e. check watchers first). |
|
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259 | 14. If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
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260 | was used, return, otherwise continue with step #1. |
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261 | |
234 | =item ev_unloop (loop, how) |
262 | =item ev_unloop (loop, how) |
235 | |
263 | |
236 | Can be used to make a call to C<ev_loop> return early. The C<how> argument |
264 | Can be used to make a call to C<ev_loop> return early (but only after it |
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265 | has processed all outstanding events). The C<how> argument must be either |
237 | must be either C<EVUNLOOP_ONCE>, which will make the innermost C<ev_loop> |
266 | C<EVUNLOOP_ONE>, which will make the innermost C<ev_loop> call return, or |
238 | call return, or C<EVUNLOOP_ALL>, which will make all nested C<ev_loop> |
267 | C<EVUNLOOP_ALL>, which will make all nested C<ev_loop> calls return. |
239 | calls return. |
|
|
240 | |
268 | |
241 | =item ev_ref (loop) |
269 | =item ev_ref (loop) |
242 | |
270 | |
243 | =item ev_unref (loop) |
271 | =item ev_unref (loop) |
244 | |
272 | |
245 | Ref/unref can be used to add or remove a refcount on the event loop: Every |
273 | Ref/unref can be used to add or remove a reference count on the event |
246 | watcher keeps one reference. If you have a long-runing watcher you never |
274 | loop: Every watcher keeps one reference, and as long as the reference |
247 | unregister that should not keep ev_loop from running, ev_unref() after |
275 | count is nonzero, C<ev_loop> will not return on its own. If you have |
248 | starting, and ev_ref() before stopping it. Libev itself uses this for |
276 | a watcher you never unregister that should not keep C<ev_loop> from |
249 | example for its internal signal pipe: It is not visible to you as a user |
277 | returning, ev_unref() after starting, and ev_ref() before stopping it. For |
250 | and should not keep C<ev_loop> from exiting if the work is done. It is |
278 | example, libev itself uses this for its internal signal pipe: It is not |
251 | also an excellent way to do this for generic recurring timers or from |
279 | visible to the libev user and should not keep C<ev_loop> from exiting if |
252 | within third-party libraries. Just remember to unref after start and ref |
280 | no event watchers registered by it are active. It is also an excellent |
253 | before stop. |
281 | way to do this for generic recurring timers or from within third-party |
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282 | libraries. Just remember to I<unref after start> and I<ref before stop>. |
254 | |
283 | |
255 | =back |
284 | =back |
256 | |
285 | |
257 | =head1 ANATOMY OF A WATCHER |
286 | =head1 ANATOMY OF A WATCHER |
258 | |
287 | |
259 | A watcher is a structure that you create and register to record your |
288 | A watcher is a structure that you create and register to record your |
260 | interest in some event. For instance, if you want to wait for STDIN to |
289 | interest in some event. For instance, if you want to wait for STDIN to |
261 | become readable, you would create an ev_io watcher for that: |
290 | become readable, you would create an C<ev_io> watcher for that: |
262 | |
291 | |
263 | static void my_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
292 | static void my_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
264 | { |
293 | { |
265 | ev_io_stop (w); |
294 | ev_io_stop (w); |
266 | ev_unloop (loop, EVUNLOOP_ALL); |
295 | ev_unloop (loop, EVUNLOOP_ALL); |
… | |
… | |
295 | |
324 | |
296 | As long as your watcher is active (has been started but not stopped) you |
325 | As long as your watcher is active (has been started but not stopped) you |
297 | must not touch the values stored in it. Most specifically you must never |
326 | must not touch the values stored in it. Most specifically you must never |
298 | reinitialise it or call its set method. |
327 | reinitialise it or call its set method. |
299 | |
328 | |
300 | You cna check whether an event is active by calling the C<ev_is_active |
329 | You can check whether an event is active by calling the C<ev_is_active |
301 | (watcher *)> macro. To see whether an event is outstanding (but the |
330 | (watcher *)> macro. To see whether an event is outstanding (but the |
302 | callback for it has not been called yet) you cna use the C<ev_is_pending |
331 | callback for it has not been called yet) you can use the C<ev_is_pending |
303 | (watcher *)> macro. |
332 | (watcher *)> macro. |
304 | |
333 | |
305 | Each and every callback receives the event loop pointer as first, the |
334 | Each and every callback receives the event loop pointer as first, the |
306 | registered watcher structure as second, and a bitset of received events as |
335 | registered watcher structure as second, and a bitset of received events as |
307 | third argument. |
336 | third argument. |
308 | |
337 | |
309 | The rceeived events usually include a single bit per event type received |
338 | The received events usually include a single bit per event type received |
310 | (you can receive multiple events at the same time). The possible bit masks |
339 | (you can receive multiple events at the same time). The possible bit masks |
311 | are: |
340 | are: |
312 | |
341 | |
313 | =over 4 |
342 | =over 4 |
314 | |
343 | |
315 | =item EV_READ |
344 | =item C<EV_READ> |
316 | |
345 | |
317 | =item EV_WRITE |
346 | =item C<EV_WRITE> |
318 | |
347 | |
319 | The file descriptor in the ev_io watcher has become readable and/or |
348 | The file descriptor in the C<ev_io> watcher has become readable and/or |
320 | writable. |
349 | writable. |
321 | |
350 | |
322 | =item EV_TIMEOUT |
351 | =item C<EV_TIMEOUT> |
323 | |
352 | |
324 | The ev_timer watcher has timed out. |
353 | The C<ev_timer> watcher has timed out. |
325 | |
354 | |
326 | =item EV_PERIODIC |
355 | =item C<EV_PERIODIC> |
327 | |
356 | |
328 | The ev_periodic watcher has timed out. |
357 | The C<ev_periodic> watcher has timed out. |
329 | |
358 | |
330 | =item EV_SIGNAL |
359 | =item C<EV_SIGNAL> |
331 | |
360 | |
332 | The signal specified in the ev_signal watcher has been received by a thread. |
361 | The signal specified in the C<ev_signal> watcher has been received by a thread. |
333 | |
362 | |
334 | =item EV_CHILD |
363 | =item C<EV_CHILD> |
335 | |
364 | |
336 | The pid specified in the ev_child watcher has received a status change. |
365 | The pid specified in the C<ev_child> watcher has received a status change. |
337 | |
366 | |
338 | =item EV_IDLE |
367 | =item C<EV_IDLE> |
339 | |
368 | |
340 | The ev_idle watcher has determined that you have nothing better to do. |
369 | The C<ev_idle> watcher has determined that you have nothing better to do. |
341 | |
370 | |
342 | =item EV_PREPARE |
371 | =item C<EV_PREPARE> |
343 | |
372 | |
344 | =item EV_CHECK |
373 | =item C<EV_CHECK> |
345 | |
374 | |
346 | All ev_prepare watchers are invoked just I<before> C<ev_loop> starts |
375 | All C<ev_prepare> watchers are invoked just I<before> C<ev_loop> starts |
347 | to gather new events, and all ev_check watchers are invoked just after |
376 | to gather new events, and all C<ev_check> watchers are invoked just after |
348 | C<ev_loop> has gathered them, but before it invokes any callbacks for any |
377 | C<ev_loop> has gathered them, but before it invokes any callbacks for any |
349 | received events. Callbacks of both watcher types can start and stop as |
378 | received events. Callbacks of both watcher types can start and stop as |
350 | many watchers as they want, and all of them will be taken into account |
379 | many watchers as they want, and all of them will be taken into account |
351 | (for example, a ev_prepare watcher might start an idle watcher to keep |
380 | (for example, a C<ev_prepare> watcher might start an idle watcher to keep |
352 | C<ev_loop> from blocking). |
381 | C<ev_loop> from blocking). |
353 | |
382 | |
354 | =item EV_ERROR |
383 | =item C<EV_ERROR> |
355 | |
384 | |
356 | An unspecified error has occured, the watcher has been stopped. This might |
385 | An unspecified error has occured, the watcher has been stopped. This might |
357 | happen because the watcher could not be properly started because libev |
386 | happen because the watcher could not be properly started because libev |
358 | ran out of memory, a file descriptor was found to be closed or any other |
387 | ran out of memory, a file descriptor was found to be closed or any other |
359 | problem. You best act on it by reporting the problem and somehow coping |
388 | problem. You best act on it by reporting the problem and somehow coping |
… | |
… | |
368 | =back |
397 | =back |
369 | |
398 | |
370 | =head2 ASSOCIATING CUSTOM DATA WITH A WATCHER |
399 | =head2 ASSOCIATING CUSTOM DATA WITH A WATCHER |
371 | |
400 | |
372 | Each watcher has, by default, a member C<void *data> that you can change |
401 | Each watcher has, by default, a member C<void *data> that you can change |
373 | and read at any time, libev will completely ignore it. This cna be used |
402 | and read at any time, libev will completely ignore it. This can be used |
374 | to associate arbitrary data with your watcher. If you need more data and |
403 | to associate arbitrary data with your watcher. If you need more data and |
375 | don't want to allocate memory and store a pointer to it in that data |
404 | don't want to allocate memory and store a pointer to it in that data |
376 | member, you can also "subclass" the watcher type and provide your own |
405 | member, you can also "subclass" the watcher type and provide your own |
377 | data: |
406 | data: |
378 | |
407 | |
… | |
… | |
400 | =head1 WATCHER TYPES |
429 | =head1 WATCHER TYPES |
401 | |
430 | |
402 | This section describes each watcher in detail, but will not repeat |
431 | This section describes each watcher in detail, but will not repeat |
403 | information given in the last section. |
432 | information given in the last section. |
404 | |
433 | |
405 | =head2 struct ev_io - is my file descriptor readable or writable |
434 | =head2 C<ev_io> - is this file descriptor readable or writable |
406 | |
435 | |
407 | I/O watchers check whether a file descriptor is readable or writable |
436 | I/O watchers check whether a file descriptor is readable or writable |
408 | in each iteration of the event loop (This behaviour is called |
437 | in each iteration of the event loop (This behaviour is called |
409 | level-triggering because you keep receiving events as long as the |
438 | level-triggering because you keep receiving events as long as the |
410 | condition persists. Remember you cna stop the watcher if you don't want to |
439 | condition persists. Remember you can stop the watcher if you don't want to |
411 | act on the event and neither want to receive future events). |
440 | act on the event and neither want to receive future events). |
412 | |
441 | |
|
|
442 | In general you can register as many read and/or write event watchers per |
|
|
443 | fd as you want (as long as you don't confuse yourself). Setting all file |
|
|
444 | descriptors to non-blocking mode is also usually a good idea (but not |
|
|
445 | required if you know what you are doing). |
|
|
446 | |
|
|
447 | You have to be careful with dup'ed file descriptors, though. Some backends |
|
|
448 | (the linux epoll backend is a notable example) cannot handle dup'ed file |
|
|
449 | descriptors correctly if you register interest in two or more fds pointing |
|
|
450 | to the same underlying file/socket etc. description (that is, they share |
|
|
451 | the same underlying "file open"). |
|
|
452 | |
|
|
453 | If you must do this, then force the use of a known-to-be-good backend |
|
|
454 | (at the time of this writing, this includes only EVMETHOD_SELECT and |
|
|
455 | EVMETHOD_POLL). |
|
|
456 | |
413 | =over 4 |
457 | =over 4 |
414 | |
458 | |
415 | =item ev_io_init (ev_io *, callback, int fd, int events) |
459 | =item ev_io_init (ev_io *, callback, int fd, int events) |
416 | |
460 | |
417 | =item ev_io_set (ev_io *, int fd, int events) |
461 | =item ev_io_set (ev_io *, int fd, int events) |
418 | |
462 | |
419 | Configures an ev_io watcher. The fd is the file descriptor to rceeive |
463 | Configures an C<ev_io> watcher. The fd is the file descriptor to rceeive |
420 | events for and events is either C<EV_READ>, C<EV_WRITE> or C<EV_READ | |
464 | events for and events is either C<EV_READ>, C<EV_WRITE> or C<EV_READ | |
421 | EV_WRITE> to receive the given events. |
465 | EV_WRITE> to receive the given events. |
422 | |
466 | |
423 | =back |
467 | =back |
424 | |
468 | |
425 | =head2 struct ev_timer - relative and optionally recurring timeouts |
469 | =head2 C<ev_timer> - relative and optionally recurring timeouts |
426 | |
470 | |
427 | Timer watchers are simple relative timers that generate an event after a |
471 | Timer watchers are simple relative timers that generate an event after a |
428 | given time, and optionally repeating in regular intervals after that. |
472 | given time, and optionally repeating in regular intervals after that. |
429 | |
473 | |
430 | The timers are based on real time, that is, if you register an event that |
474 | The timers are based on real time, that is, if you register an event that |
431 | times out after an hour and youreset your system clock to last years |
475 | times out after an hour and you reset your system clock to last years |
432 | time, it will still time out after (roughly) and hour. "Roughly" because |
476 | time, it will still time out after (roughly) and hour. "Roughly" because |
433 | detecting time jumps is hard, and soem inaccuracies are unavoidable (the |
477 | detecting time jumps is hard, and soem inaccuracies are unavoidable (the |
434 | monotonic clock option helps a lot here). |
478 | monotonic clock option helps a lot here). |
|
|
479 | |
|
|
480 | The relative timeouts are calculated relative to the C<ev_now ()> |
|
|
481 | time. This is usually the right thing as this timestamp refers to the time |
|
|
482 | of the event triggering whatever timeout you are modifying/starting. If |
|
|
483 | you suspect event processing to be delayed and you *need* to base the timeout |
|
|
484 | on the current time, use something like this to adjust for this: |
|
|
485 | |
|
|
486 | ev_timer_set (&timer, after + ev_now () - ev_time (), 0.); |
435 | |
487 | |
436 | =over 4 |
488 | =over 4 |
437 | |
489 | |
438 | =item ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat) |
490 | =item ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat) |
439 | |
491 | |
… | |
… | |
445 | later, again, and again, until stopped manually. |
497 | later, again, and again, until stopped manually. |
446 | |
498 | |
447 | The timer itself will do a best-effort at avoiding drift, that is, if you |
499 | The timer itself will do a best-effort at avoiding drift, that is, if you |
448 | configure a timer to trigger every 10 seconds, then it will trigger at |
500 | configure a timer to trigger every 10 seconds, then it will trigger at |
449 | exactly 10 second intervals. If, however, your program cannot keep up with |
501 | exactly 10 second intervals. If, however, your program cannot keep up with |
450 | the timer (ecause it takes longer than those 10 seconds to do stuff) the |
502 | the timer (because it takes longer than those 10 seconds to do stuff) the |
451 | timer will not fire more than once per event loop iteration. |
503 | timer will not fire more than once per event loop iteration. |
452 | |
504 | |
453 | =item ev_timer_again (loop) |
505 | =item ev_timer_again (loop) |
454 | |
506 | |
455 | This will act as if the timer timed out and restart it again if it is |
507 | This will act as if the timer timed out and restart it again if it is |
… | |
… | |
462 | |
514 | |
463 | This sounds a bit complicated, but here is a useful and typical |
515 | This sounds a bit complicated, but here is a useful and typical |
464 | example: Imagine you have a tcp connection and you want a so-called idle |
516 | example: Imagine you have a tcp connection and you want a so-called idle |
465 | timeout, that is, you want to be called when there have been, say, 60 |
517 | timeout, that is, you want to be called when there have been, say, 60 |
466 | seconds of inactivity on the socket. The easiest way to do this is to |
518 | seconds of inactivity on the socket. The easiest way to do this is to |
467 | configure an ev_timer with after=repeat=60 and calling ev_timer_again each |
519 | configure an C<ev_timer> with after=repeat=60 and calling ev_timer_again each |
468 | time you successfully read or write some data. If you go into an idle |
520 | time you successfully read or write some data. If you go into an idle |
469 | state where you do not expect data to travel on the socket, you can stop |
521 | state where you do not expect data to travel on the socket, you can stop |
470 | the timer, and again will automatically restart it if need be. |
522 | the timer, and again will automatically restart it if need be. |
471 | |
523 | |
472 | =back |
524 | =back |
473 | |
525 | |
474 | =head2 ev_periodic - to cron or not to cron it |
526 | =head2 C<ev_periodic> - to cron or not to cron |
475 | |
527 | |
476 | Periodic watchers are also timers of a kind, but they are very versatile |
528 | Periodic watchers are also timers of a kind, but they are very versatile |
477 | (and unfortunately a bit complex). |
529 | (and unfortunately a bit complex). |
478 | |
530 | |
479 | Unlike ev_timer's, they are not based on real time (or relative time) |
531 | Unlike C<ev_timer>'s, they are not based on real time (or relative time) |
480 | but on wallclock time (absolute time). You can tell a periodic watcher |
532 | but on wallclock time (absolute time). You can tell a periodic watcher |
481 | to trigger "at" some specific point in time. For example, if you tell a |
533 | to trigger "at" some specific point in time. For example, if you tell a |
482 | periodic watcher to trigger in 10 seconds (by specifiying e.g. c<ev_now () |
534 | periodic watcher to trigger in 10 seconds (by specifiying e.g. c<ev_now () |
483 | + 10.>) and then reset your system clock to the last year, then it will |
535 | + 10.>) and then reset your system clock to the last year, then it will |
484 | take a year to trigger the event (unlike an ev_timer, which would trigger |
536 | take a year to trigger the event (unlike an C<ev_timer>, which would trigger |
485 | roughly 10 seconds later and of course not if you reset your system time |
537 | roughly 10 seconds later and of course not if you reset your system time |
486 | again). |
538 | again). |
487 | |
539 | |
488 | They can also be used to implement vastly more complex timers, such as |
540 | They can also be used to implement vastly more complex timers, such as |
489 | triggering an event on eahc midnight, local time. |
541 | triggering an event on eahc midnight, local time. |
… | |
… | |
518 | |
570 | |
519 | ev_periodic_set (&periodic, 0., 3600., 0); |
571 | ev_periodic_set (&periodic, 0., 3600., 0); |
520 | |
572 | |
521 | This doesn't mean there will always be 3600 seconds in between triggers, |
573 | This doesn't mean there will always be 3600 seconds in between triggers, |
522 | but only that the the callback will be called when the system time shows a |
574 | but only that the the callback will be called when the system time shows a |
523 | full hour (UTC), or more correct, when the system time is evenly divisible |
575 | full hour (UTC), or more correctly, when the system time is evenly divisible |
524 | by 3600. |
576 | by 3600. |
525 | |
577 | |
526 | Another way to think about it (for the mathematically inclined) is that |
578 | Another way to think about it (for the mathematically inclined) is that |
527 | ev_periodic will try to run the callback in this mode at the next possible |
579 | C<ev_periodic> will try to run the callback in this mode at the next possible |
528 | time where C<time = at (mod interval)>, regardless of any time jumps. |
580 | time where C<time = at (mod interval)>, regardless of any time jumps. |
529 | |
581 | |
530 | =item * manual reschedule mode (reschedule_cb = callback) |
582 | =item * manual reschedule mode (reschedule_cb = callback) |
531 | |
583 | |
532 | In this mode the values for C<interval> and C<at> are both being |
584 | In this mode the values for C<interval> and C<at> are both being |
533 | ignored. Instead, each time the periodic watcher gets scheduled, the |
585 | ignored. Instead, each time the periodic watcher gets scheduled, the |
534 | reschedule callback will be called with the watcher as first, and the |
586 | reschedule callback will be called with the watcher as first, and the |
535 | current time as second argument. |
587 | current time as second argument. |
536 | |
588 | |
537 | NOTE: I<This callback MUST NOT stop or destroy the periodic or any other |
589 | NOTE: I<This callback MUST NOT stop or destroy any periodic watcher, |
538 | periodic watcher, ever, or make any event loop modificstions>. If you need |
590 | ever, or make any event loop modifications>. If you need to stop it, |
539 | to stop it, return 1e30 (or so, fudge fudge) and stop it afterwards. |
591 | return C<now + 1e30> (or so, fudge fudge) and stop it afterwards (e.g. by |
|
|
592 | starting a prepare watcher). |
540 | |
593 | |
541 | Its prototype is c<ev_tstamp (*reschedule_cb)(struct ev_periodic *w, |
594 | Its prototype is C<ev_tstamp (*reschedule_cb)(struct ev_periodic *w, |
542 | ev_tstamp now)>, e.g.: |
595 | ev_tstamp now)>, e.g.: |
543 | |
596 | |
544 | static ev_tstamp my_rescheduler (struct ev_periodic *w, ev_tstamp now) |
597 | static ev_tstamp my_rescheduler (struct ev_periodic *w, ev_tstamp now) |
545 | { |
598 | { |
546 | return now + 60.; |
599 | return now + 60.; |
… | |
… | |
549 | It must return the next time to trigger, based on the passed time value |
602 | It must return the next time to trigger, based on the passed time value |
550 | (that is, the lowest time value larger than to the second argument). It |
603 | (that is, the lowest time value larger than to the second argument). It |
551 | will usually be called just before the callback will be triggered, but |
604 | will usually be called just before the callback will be triggered, but |
552 | might be called at other times, too. |
605 | might be called at other times, too. |
553 | |
606 | |
|
|
607 | NOTE: I<< This callback must always return a time that is later than the |
|
|
608 | passed C<now> value >>. Not even C<now> itself will do, it I<must> be larger. |
|
|
609 | |
554 | This can be used to create very complex timers, such as a timer that |
610 | This can be used to create very complex timers, such as a timer that |
555 | triggers on each midnight, local time. To do this, you would calculate the |
611 | triggers on each midnight, local time. To do this, you would calculate the |
556 | next midnight after C<now> and return the timestamp value for this. How you do this |
612 | next midnight after C<now> and return the timestamp value for this. How |
557 | is, again, up to you (but it is not trivial). |
613 | you do this is, again, up to you (but it is not trivial, which is the main |
|
|
614 | reason I omitted it as an example). |
558 | |
615 | |
559 | =back |
616 | =back |
560 | |
617 | |
561 | =item ev_periodic_again (loop, ev_periodic *) |
618 | =item ev_periodic_again (loop, ev_periodic *) |
562 | |
619 | |
… | |
… | |
565 | a different time than the last time it was called (e.g. in a crond like |
622 | a different time than the last time it was called (e.g. in a crond like |
566 | program when the crontabs have changed). |
623 | program when the crontabs have changed). |
567 | |
624 | |
568 | =back |
625 | =back |
569 | |
626 | |
570 | =head2 ev_signal - signal me when a signal gets signalled |
627 | =head2 C<ev_signal> - signal me when a signal gets signalled |
571 | |
628 | |
572 | Signal watchers will trigger an event when the process receives a specific |
629 | Signal watchers will trigger an event when the process receives a specific |
573 | signal one or more times. Even though signals are very asynchronous, libev |
630 | signal one or more times. Even though signals are very asynchronous, libev |
574 | will try its best to deliver signals synchronously, i.e. as part of the |
631 | will try it's best to deliver signals synchronously, i.e. as part of the |
575 | normal event processing, like any other event. |
632 | normal event processing, like any other event. |
576 | |
633 | |
577 | You cna configure as many watchers as you like per signal. Only when the |
634 | You can configure as many watchers as you like per signal. Only when the |
578 | first watcher gets started will libev actually register a signal watcher |
635 | first watcher gets started will libev actually register a signal watcher |
579 | with the kernel (thus it coexists with your own signal handlers as long |
636 | with the kernel (thus it coexists with your own signal handlers as long |
580 | as you don't register any with libev). Similarly, when the last signal |
637 | as you don't register any with libev). Similarly, when the last signal |
581 | watcher for a signal is stopped libev will reset the signal handler to |
638 | watcher for a signal is stopped libev will reset the signal handler to |
582 | SIG_DFL (regardless of what it was set to before). |
639 | SIG_DFL (regardless of what it was set to before). |
… | |
… | |
590 | Configures the watcher to trigger on the given signal number (usually one |
647 | Configures the watcher to trigger on the given signal number (usually one |
591 | of the C<SIGxxx> constants). |
648 | of the C<SIGxxx> constants). |
592 | |
649 | |
593 | =back |
650 | =back |
594 | |
651 | |
595 | =head2 ev_child - wait for pid status changes |
652 | =head2 C<ev_child> - wait for pid status changes |
596 | |
653 | |
597 | Child watchers trigger when your process receives a SIGCHLD in response to |
654 | Child watchers trigger when your process receives a SIGCHLD in response to |
598 | some child status changes (most typically when a child of yours dies). |
655 | some child status changes (most typically when a child of yours dies). |
599 | |
656 | |
600 | =over 4 |
657 | =over 4 |
… | |
… | |
604 | =item ev_child_set (ev_child *, int pid) |
661 | =item ev_child_set (ev_child *, int pid) |
605 | |
662 | |
606 | Configures the watcher to wait for status changes of process C<pid> (or |
663 | Configures the watcher to wait for status changes of process C<pid> (or |
607 | I<any> process if C<pid> is specified as C<0>). The callback can look |
664 | I<any> process if C<pid> is specified as C<0>). The callback can look |
608 | at the C<rstatus> member of the C<ev_child> watcher structure to see |
665 | at the C<rstatus> member of the C<ev_child> watcher structure to see |
609 | the status word (use the macros from C<sys/wait.h>). The C<rpid> member |
666 | the status word (use the macros from C<sys/wait.h> and see your systems |
610 | contains the pid of the process causing the status change. |
667 | C<waitpid> documentation). The C<rpid> member contains the pid of the |
|
|
668 | process causing the status change. |
611 | |
669 | |
612 | =back |
670 | =back |
613 | |
671 | |
614 | =head2 ev_idle - when you've got nothing better to do |
672 | =head2 C<ev_idle> - when you've got nothing better to do |
615 | |
673 | |
616 | Idle watchers trigger events when there are no other I/O or timer (or |
674 | Idle watchers trigger events when there are no other events are pending |
617 | periodic) events pending. That is, as long as your process is busy |
675 | (prepare, check and other idle watchers do not count). That is, as long |
618 | handling sockets or timeouts it will not be called. But when your process |
676 | as your process is busy handling sockets or timeouts (or even signals, |
619 | is idle all idle watchers are being called again and again - until |
677 | imagine) it will not be triggered. But when your process is idle all idle |
|
|
678 | watchers are being called again and again, once per event loop iteration - |
620 | stopped, that is, or your process receives more events. |
679 | until stopped, that is, or your process receives more events and becomes |
|
|
680 | busy. |
621 | |
681 | |
622 | The most noteworthy effect is that as long as any idle watchers are |
682 | The most noteworthy effect is that as long as any idle watchers are |
623 | active, the process will not block when waiting for new events. |
683 | active, the process will not block when waiting for new events. |
624 | |
684 | |
625 | Apart from keeping your process non-blocking (which is a useful |
685 | Apart from keeping your process non-blocking (which is a useful |
… | |
… | |
635 | kind. There is a C<ev_idle_set> macro, but using it is utterly pointless, |
695 | kind. There is a C<ev_idle_set> macro, but using it is utterly pointless, |
636 | believe me. |
696 | believe me. |
637 | |
697 | |
638 | =back |
698 | =back |
639 | |
699 | |
640 | =head2 prepare and check - your hooks into the event loop |
700 | =head2 C<ev_prepare> and C<ev_check> - customise your event loop |
641 | |
701 | |
642 | Prepare and check watchers usually (but not always) are used in |
702 | Prepare and check watchers are usually (but not always) used in tandem: |
643 | tandom. Prepare watchers get invoked before the process blocks and check |
703 | prepare watchers get invoked before the process blocks and check watchers |
644 | watchers afterwards. |
704 | afterwards. |
645 | |
705 | |
646 | Their main purpose is to integrate other event mechanisms into libev. This |
706 | Their main purpose is to integrate other event mechanisms into libev. This |
647 | could be used, for example, to track variable changes, implement your own |
707 | could be used, for example, to track variable changes, implement your own |
648 | watchers, integrate net-snmp or a coroutine library and lots more. |
708 | watchers, integrate net-snmp or a coroutine library and lots more. |
649 | |
709 | |
650 | This is done by examining in each prepare call which file descriptors need |
710 | This is done by examining in each prepare call which file descriptors need |
651 | to be watched by the other library, registering ev_io watchers for them |
711 | to be watched by the other library, registering C<ev_io> watchers for |
652 | and starting an ev_timer watcher for any timeouts (many libraries provide |
712 | them and starting an C<ev_timer> watcher for any timeouts (many libraries |
653 | just this functionality). Then, in the check watcher you check for any |
713 | provide just this functionality). Then, in the check watcher you check for |
654 | events that occured (by making your callbacks set soem flags for example) |
714 | any events that occured (by checking the pending status of all watchers |
655 | and call back into the library. |
715 | and stopping them) and call back into the library. The I/O and timer |
|
|
716 | callbacks will never actually be called (but must be valid nevertheless, |
|
|
717 | because you never know, you know?). |
656 | |
718 | |
657 | As another example, the perl Coro module uses these hooks to integrate |
719 | As another example, the Perl Coro module uses these hooks to integrate |
658 | coroutines into libev programs, by yielding to other active coroutines |
720 | coroutines into libev programs, by yielding to other active coroutines |
659 | during each prepare and only letting the process block if no coroutines |
721 | during each prepare and only letting the process block if no coroutines |
660 | are ready to run. |
722 | are ready to run (it's actually more complicated: it only runs coroutines |
|
|
723 | with priority higher than or equal to the event loop and one coroutine |
|
|
724 | of lower priority, but only once, using idle watchers to keep the event |
|
|
725 | loop from blocking if lower-priority coroutines are active, thus mapping |
|
|
726 | low-priority coroutines to idle/background tasks). |
661 | |
727 | |
662 | =over 4 |
728 | =over 4 |
663 | |
729 | |
664 | =item ev_prepare_init (ev_prepare *, callback) |
730 | =item ev_prepare_init (ev_prepare *, callback) |
665 | |
731 | |
666 | =item ev_check_init (ev_check *, callback) |
732 | =item ev_check_init (ev_check *, callback) |
667 | |
733 | |
668 | Initialises and configures the prepare or check watcher - they have no |
734 | Initialises and configures the prepare or check watcher - they have no |
669 | parameters of any kind. There are C<ev_prepare_set> and C<ev_check_set> |
735 | parameters of any kind. There are C<ev_prepare_set> and C<ev_check_set> |
670 | macros, but using them is utterly, utterly pointless. |
736 | macros, but using them is utterly, utterly and completely pointless. |
671 | |
737 | |
672 | =back |
738 | =back |
673 | |
739 | |
674 | =head1 OTHER FUNCTIONS |
740 | =head1 OTHER FUNCTIONS |
675 | |
741 | |
676 | There are some other fucntions of possible interest. Described. Here. Now. |
742 | There are some other functions of possible interest. Described. Here. Now. |
677 | |
743 | |
678 | =over 4 |
744 | =over 4 |
679 | |
745 | |
680 | =item ev_once (loop, int fd, int events, ev_tstamp timeout, callback) |
746 | =item ev_once (loop, int fd, int events, ev_tstamp timeout, callback) |
681 | |
747 | |
682 | This function combines a simple timer and an I/O watcher, calls your |
748 | This function combines a simple timer and an I/O watcher, calls your |
683 | callback on whichever event happens first and automatically stop both |
749 | callback on whichever event happens first and automatically stop both |
684 | watchers. This is useful if you want to wait for a single event on an fd |
750 | watchers. This is useful if you want to wait for a single event on an fd |
685 | or timeout without havign to allocate/configure/start/stop/free one or |
751 | or timeout without having to allocate/configure/start/stop/free one or |
686 | more watchers yourself. |
752 | more watchers yourself. |
687 | |
753 | |
688 | If C<fd> is less than 0, then no I/O watcher will be started and events is |
754 | If C<fd> is less than 0, then no I/O watcher will be started and events |
689 | ignored. Otherwise, an ev_io watcher for the given C<fd> and C<events> set |
755 | is being ignored. Otherwise, an C<ev_io> watcher for the given C<fd> and |
690 | will be craeted and started. |
756 | C<events> set will be craeted and started. |
691 | |
757 | |
692 | If C<timeout> is less than 0, then no timeout watcher will be |
758 | If C<timeout> is less than 0, then no timeout watcher will be |
693 | started. Otherwise an ev_timer watcher with after = C<timeout> (and repeat |
759 | started. Otherwise an C<ev_timer> watcher with after = C<timeout> (and |
694 | = 0) will be started. |
760 | repeat = 0) will be started. While C<0> is a valid timeout, it is of |
|
|
761 | dubious value. |
695 | |
762 | |
696 | The callback has the type C<void (*cb)(int revents, void *arg)> and |
763 | The callback has the type C<void (*cb)(int revents, void *arg)> and gets |
697 | gets passed an events set (normally a combination of EV_ERROR, EV_READ, |
764 | passed an C<revents> set like normal event callbacks (a combination of |
698 | EV_WRITE or EV_TIMEOUT) and the C<arg> value passed to C<ev_once>: |
765 | C<EV_ERROR>, C<EV_READ>, C<EV_WRITE> or C<EV_TIMEOUT>) and the C<arg> |
|
|
766 | value passed to C<ev_once>: |
699 | |
767 | |
700 | static void stdin_ready (int revents, void *arg) |
768 | static void stdin_ready (int revents, void *arg) |
701 | { |
769 | { |
702 | if (revents & EV_TIMEOUT) |
770 | if (revents & EV_TIMEOUT) |
703 | /* doh, nothing entered */ |
771 | /* doh, nothing entered */; |
704 | else if (revents & EV_READ) |
772 | else if (revents & EV_READ) |
705 | /* stdin might have data for us, joy! */ |
773 | /* stdin might have data for us, joy! */; |
706 | } |
774 | } |
707 | |
775 | |
708 | ev_once (STDIN_FILENO, EV_READm 10., stdin_ready, 0); |
776 | ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0); |
709 | |
777 | |
710 | =item ev_feed_event (loop, watcher, int events) |
778 | =item ev_feed_event (loop, watcher, int events) |
711 | |
779 | |
712 | Feeds the given event set into the event loop, as if the specified event |
780 | Feeds the given event set into the event loop, as if the specified event |
713 | has happened for the specified watcher (which must be a pointer to an |
781 | had happened for the specified watcher (which must be a pointer to an |
714 | initialised but not necessarily active event watcher). |
782 | initialised but not necessarily started event watcher). |
715 | |
783 | |
716 | =item ev_feed_fd_event (loop, int fd, int revents) |
784 | =item ev_feed_fd_event (loop, int fd, int revents) |
717 | |
785 | |
718 | Feed an event on the given fd, as if a file descriptor backend detected it. |
786 | Feed an event on the given fd, as if a file descriptor backend detected |
|
|
787 | the given events it. |
719 | |
788 | |
720 | =item ev_feed_signal_event (loop, int signum) |
789 | =item ev_feed_signal_event (loop, int signum) |
721 | |
790 | |
722 | Feed an event as if the given signal occured (loop must be the default loop!). |
791 | Feed an event as if the given signal occured (loop must be the default loop!). |
723 | |
792 | |
724 | =back |
793 | =back |
725 | |
794 | |
|
|
795 | =head1 LIBEVENT EMULATION |
|
|
796 | |
|
|
797 | Libev offers a compatibility emulation layer for libevent. It cannot |
|
|
798 | emulate the internals of libevent, so here are some usage hints: |
|
|
799 | |
|
|
800 | =over 4 |
|
|
801 | |
|
|
802 | =item * Use it by including <event.h>, as usual. |
|
|
803 | |
|
|
804 | =item * The following members are fully supported: ev_base, ev_callback, |
|
|
805 | ev_arg, ev_fd, ev_res, ev_events. |
|
|
806 | |
|
|
807 | =item * Avoid using ev_flags and the EVLIST_*-macros, while it is |
|
|
808 | maintained by libev, it does not work exactly the same way as in libevent (consider |
|
|
809 | it a private API). |
|
|
810 | |
|
|
811 | =item * Priorities are not currently supported. Initialising priorities |
|
|
812 | will fail and all watchers will have the same priority, even though there |
|
|
813 | is an ev_pri field. |
|
|
814 | |
|
|
815 | =item * Other members are not supported. |
|
|
816 | |
|
|
817 | =item * The libev emulation is I<not> ABI compatible to libevent, you need |
|
|
818 | to use the libev header file and library. |
|
|
819 | |
|
|
820 | =back |
|
|
821 | |
|
|
822 | =head1 C++ SUPPORT |
|
|
823 | |
|
|
824 | TBD. |
|
|
825 | |
726 | =head1 AUTHOR |
826 | =head1 AUTHOR |
727 | |
827 | |
728 | Marc Lehmann <libev@schmorp.de>. |
828 | Marc Lehmann <libev@schmorp.de>. |
729 | |
829 | |