… | |
… | |
127 | .\} |
127 | .\} |
128 | .rm #[ #] #H #V #F C |
128 | .rm #[ #] #H #V #F C |
129 | .\" ======================================================================== |
129 | .\" ======================================================================== |
130 | .\" |
130 | .\" |
131 | .IX Title ""<STANDARD INPUT>" 1" |
131 | .IX Title ""<STANDARD INPUT>" 1" |
132 | .TH "<STANDARD INPUT>" 1 "2007-11-22" "perl v5.8.8" "User Contributed Perl Documentation" |
132 | .TH "<STANDARD INPUT>" 1 "2007-11-27" "perl v5.8.8" "User Contributed Perl Documentation" |
133 | .SH "NAME" |
133 | .SH "NAME" |
134 | libev \- a high performance full\-featured event loop written in C |
134 | libev \- a high performance full\-featured event loop written in C |
135 | .SH "SYNOPSIS" |
135 | .SH "SYNOPSIS" |
136 | .IX Header "SYNOPSIS" |
136 | .IX Header "SYNOPSIS" |
137 | .Vb 1 |
137 | .Vb 1 |
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… | |
173 | .IX Header "TIME REPRESENTATION" |
173 | .IX Header "TIME REPRESENTATION" |
174 | Libev represents time as a single floating point number, representing the |
174 | Libev represents time as a single floating point number, representing the |
175 | (fractional) number of seconds since the (\s-1POSIX\s0) epoch (somewhere near |
175 | (fractional) number of seconds since the (\s-1POSIX\s0) epoch (somewhere near |
176 | the beginning of 1970, details are complicated, don't ask). This type is |
176 | the beginning of 1970, details are complicated, don't ask). This type is |
177 | called \f(CW\*(C`ev_tstamp\*(C'\fR, which is what you should use too. It usually aliases |
177 | called \f(CW\*(C`ev_tstamp\*(C'\fR, which is what you should use too. It usually aliases |
178 | to the double type in C. |
178 | to the \f(CW\*(C`double\*(C'\fR type in C, and when you need to do any calculations on |
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179 | it, you should treat it as such. |
179 | .SH "GLOBAL FUNCTIONS" |
180 | .SH "GLOBAL FUNCTIONS" |
180 | .IX Header "GLOBAL FUNCTIONS" |
181 | .IX Header "GLOBAL FUNCTIONS" |
181 | These functions can be called anytime, even before initialising the |
182 | These functions can be called anytime, even before initialising the |
182 | library in any way. |
183 | library in any way. |
183 | .IP "ev_tstamp ev_time ()" 4 |
184 | .IP "ev_tstamp ev_time ()" 4 |
… | |
… | |
199 | .Sp |
200 | .Sp |
200 | Usually, it's a good idea to terminate if the major versions mismatch, |
201 | Usually, it's a good idea to terminate if the major versions mismatch, |
201 | as this indicates an incompatible change. Minor versions are usually |
202 | as this indicates an incompatible change. Minor versions are usually |
202 | compatible to older versions, so a larger minor version alone is usually |
203 | compatible to older versions, so a larger minor version alone is usually |
203 | not a problem. |
204 | not a problem. |
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205 | .Sp |
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206 | Example: make sure we haven't accidentally been linked against the wrong |
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207 | version: |
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208 | .Sp |
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209 | .Vb 3 |
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210 | \& assert (("libev version mismatch", |
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211 | \& ev_version_major () == EV_VERSION_MAJOR |
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212 | \& && ev_version_minor () >= EV_VERSION_MINOR)); |
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213 | .Ve |
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214 | .IP "unsigned int ev_supported_backends ()" 4 |
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215 | .IX Item "unsigned int ev_supported_backends ()" |
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216 | Return the set of all backends (i.e. their corresponding \f(CW\*(C`EV_BACKEND_*\*(C'\fR |
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217 | value) compiled into this binary of libev (independent of their |
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218 | availability on the system you are running on). See \f(CW\*(C`ev_default_loop\*(C'\fR for |
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219 | a description of the set values. |
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220 | .Sp |
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221 | Example: make sure we have the epoll method, because yeah this is cool and |
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222 | a must have and can we have a torrent of it please!!!11 |
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223 | .Sp |
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224 | .Vb 2 |
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225 | \& assert (("sorry, no epoll, no sex", |
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226 | \& ev_supported_backends () & EVBACKEND_EPOLL)); |
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227 | .Ve |
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228 | .IP "unsigned int ev_recommended_backends ()" 4 |
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229 | .IX Item "unsigned int ev_recommended_backends ()" |
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230 | Return the set of all backends compiled into this binary of libev and also |
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231 | recommended for this platform. This set is often smaller than the one |
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232 | returned by \f(CW\*(C`ev_supported_backends\*(C'\fR, as for example kqueue is broken on |
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233 | most BSDs and will not be autodetected unless you explicitly request it |
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234 | (assuming you know what you are doing). This is the set of backends that |
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235 | libev will probe for if you specify no backends explicitly. |
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236 | .IP "unsigned int ev_embeddable_backends ()" 4 |
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237 | .IX Item "unsigned int ev_embeddable_backends ()" |
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238 | Returns the set of backends that are embeddable in other event loops. This |
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239 | is the theoretical, all\-platform, value. To find which backends |
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240 | might be supported on the current system, you would need to look at |
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241 | \&\f(CW\*(C`ev_embeddable_backends () & ev_supported_backends ()\*(C'\fR, likewise for |
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242 | recommended ones. |
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243 | .Sp |
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244 | See the description of \f(CW\*(C`ev_embed\*(C'\fR watchers for more info. |
204 | .IP "ev_set_allocator (void *(*cb)(void *ptr, long size))" 4 |
245 | .IP "ev_set_allocator (void *(*cb)(void *ptr, long size))" 4 |
205 | .IX Item "ev_set_allocator (void *(*cb)(void *ptr, long size))" |
246 | .IX Item "ev_set_allocator (void *(*cb)(void *ptr, long size))" |
206 | Sets the allocation function to use (the prototype is similar to the |
247 | Sets the allocation function to use (the prototype is similar to the |
207 | realloc C function, the semantics are identical). It is used to allocate |
248 | realloc C function, the semantics are identical). It is used to allocate |
208 | and free memory (no surprises here). If it returns zero when memory |
249 | and free memory (no surprises here). If it returns zero when memory |
… | |
… | |
210 | destructive action. The default is your system realloc function. |
251 | destructive action. The default is your system realloc function. |
211 | .Sp |
252 | .Sp |
212 | You could override this function in high-availability programs to, say, |
253 | You could override this function in high-availability programs to, say, |
213 | free some memory if it cannot allocate memory, to use a special allocator, |
254 | free some memory if it cannot allocate memory, to use a special allocator, |
214 | or even to sleep a while and retry until some memory is available. |
255 | or even to sleep a while and retry until some memory is available. |
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256 | .Sp |
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257 | Example: replace the libev allocator with one that waits a bit and then |
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258 | retries: better than mine). |
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259 | .Sp |
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260 | .Vb 6 |
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261 | \& static void * |
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262 | \& persistent_realloc (void *ptr, long size) |
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263 | \& { |
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264 | \& for (;;) |
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265 | \& { |
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266 | \& void *newptr = realloc (ptr, size); |
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267 | .Ve |
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268 | .Sp |
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269 | .Vb 2 |
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270 | \& if (newptr) |
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271 | \& return newptr; |
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272 | .Ve |
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273 | .Sp |
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274 | .Vb 3 |
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275 | \& sleep (60); |
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276 | \& } |
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277 | \& } |
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278 | .Ve |
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279 | .Sp |
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280 | .Vb 2 |
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281 | \& ... |
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282 | \& ev_set_allocator (persistent_realloc); |
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283 | .Ve |
215 | .IP "ev_set_syserr_cb (void (*cb)(const char *msg));" 4 |
284 | .IP "ev_set_syserr_cb (void (*cb)(const char *msg));" 4 |
216 | .IX Item "ev_set_syserr_cb (void (*cb)(const char *msg));" |
285 | .IX Item "ev_set_syserr_cb (void (*cb)(const char *msg));" |
217 | Set the callback function to call on a retryable syscall error (such |
286 | Set the callback function to call on a retryable syscall error (such |
218 | as failed select, poll, epoll_wait). The message is a printable string |
287 | as failed select, poll, epoll_wait). The message is a printable string |
219 | indicating the system call or subsystem causing the problem. If this |
288 | indicating the system call or subsystem causing the problem. If this |
220 | callback is set, then libev will expect it to remedy the sitution, no |
289 | callback is set, then libev will expect it to remedy the sitution, no |
221 | matter what, when it returns. That is, libev will generally retry the |
290 | matter what, when it returns. That is, libev will generally retry the |
222 | requested operation, or, if the condition doesn't go away, do bad stuff |
291 | requested operation, or, if the condition doesn't go away, do bad stuff |
223 | (such as abort). |
292 | (such as abort). |
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293 | .Sp |
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294 | Example: do the same thing as libev does internally: |
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295 | .Sp |
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296 | .Vb 6 |
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297 | \& static void |
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298 | \& fatal_error (const char *msg) |
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299 | \& { |
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300 | \& perror (msg); |
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301 | \& abort (); |
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302 | \& } |
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303 | .Ve |
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304 | .Sp |
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305 | .Vb 2 |
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306 | \& ... |
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307 | \& ev_set_syserr_cb (fatal_error); |
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308 | .Ve |
224 | .SH "FUNCTIONS CONTROLLING THE EVENT LOOP" |
309 | .SH "FUNCTIONS CONTROLLING THE EVENT LOOP" |
225 | .IX Header "FUNCTIONS CONTROLLING THE EVENT LOOP" |
310 | .IX Header "FUNCTIONS CONTROLLING THE EVENT LOOP" |
226 | An event loop is described by a \f(CW\*(C`struct ev_loop *\*(C'\fR. The library knows two |
311 | An event loop is described by a \f(CW\*(C`struct ev_loop *\*(C'\fR. The library knows two |
227 | types of such loops, the \fIdefault\fR loop, which supports signals and child |
312 | types of such loops, the \fIdefault\fR loop, which supports signals and child |
228 | events, and dynamically created loops which do not. |
313 | events, and dynamically created loops which do not. |
… | |
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236 | .IP "struct ev_loop *ev_default_loop (unsigned int flags)" 4 |
321 | .IP "struct ev_loop *ev_default_loop (unsigned int flags)" 4 |
237 | .IX Item "struct ev_loop *ev_default_loop (unsigned int flags)" |
322 | .IX Item "struct ev_loop *ev_default_loop (unsigned int flags)" |
238 | This will initialise the default event loop if it hasn't been initialised |
323 | This will initialise the default event loop if it hasn't been initialised |
239 | yet and return it. If the default loop could not be initialised, returns |
324 | yet and return it. If the default loop could not be initialised, returns |
240 | false. If it already was initialised it simply returns it (and ignores the |
325 | false. If it already was initialised it simply returns it (and ignores the |
241 | flags). |
326 | flags. If that is troubling you, check \f(CW\*(C`ev_backend ()\*(C'\fR afterwards). |
242 | .Sp |
327 | .Sp |
243 | If you don't know what event loop to use, use the one returned from this |
328 | If you don't know what event loop to use, use the one returned from this |
244 | function. |
329 | function. |
245 | .Sp |
330 | .Sp |
246 | The flags argument can be used to specify special behaviour or specific |
331 | The flags argument can be used to specify special behaviour or specific |
247 | backends to use, and is usually specified as 0 (or \s-1EVFLAG_AUTO\s0). |
332 | backends to use, and is usually specified as \f(CW0\fR (or \f(CW\*(C`EVFLAG_AUTO\*(C'\fR). |
248 | .Sp |
333 | .Sp |
249 | It supports the following flags: |
334 | The following flags are supported: |
250 | .RS 4 |
335 | .RS 4 |
251 | .ie n .IP """EVFLAG_AUTO""" 4 |
336 | .ie n .IP """EVFLAG_AUTO""" 4 |
252 | .el .IP "\f(CWEVFLAG_AUTO\fR" 4 |
337 | .el .IP "\f(CWEVFLAG_AUTO\fR" 4 |
253 | .IX Item "EVFLAG_AUTO" |
338 | .IX Item "EVFLAG_AUTO" |
254 | The default flags value. Use this if you have no clue (it's the right |
339 | The default flags value. Use this if you have no clue (it's the right |
… | |
… | |
260 | or setgid) then libev will \fInot\fR look at the environment variable |
345 | or setgid) then libev will \fInot\fR look at the environment variable |
261 | \&\f(CW\*(C`LIBEV_FLAGS\*(C'\fR. Otherwise (the default), this environment variable will |
346 | \&\f(CW\*(C`LIBEV_FLAGS\*(C'\fR. Otherwise (the default), this environment variable will |
262 | override the flags completely if it is found in the environment. This is |
347 | override the flags completely if it is found in the environment. This is |
263 | useful to try out specific backends to test their performance, or to work |
348 | useful to try out specific backends to test their performance, or to work |
264 | around bugs. |
349 | around bugs. |
265 | .ie n .IP """EVMETHOD_SELECT"" (value 1, portable select backend)" 4 |
350 | .ie n .IP """EVBACKEND_SELECT"" (value 1, portable select backend)" 4 |
266 | .el .IP "\f(CWEVMETHOD_SELECT\fR (value 1, portable select backend)" 4 |
351 | .el .IP "\f(CWEVBACKEND_SELECT\fR (value 1, portable select backend)" 4 |
267 | .IX Item "EVMETHOD_SELECT (value 1, portable select backend)" |
352 | .IX Item "EVBACKEND_SELECT (value 1, portable select backend)" |
268 | This is your standard \fIselect\fR\|(2) backend. Not \fIcompletely\fR standard, as |
353 | This is your standard \fIselect\fR\|(2) backend. Not \fIcompletely\fR standard, as |
269 | libev tries to roll its own fd_set with no limits on the number of fds, |
354 | libev tries to roll its own fd_set with no limits on the number of fds, |
270 | but if that fails, expect a fairly low limit on the number of fds when |
355 | but if that fails, expect a fairly low limit on the number of fds when |
271 | using this backend. It doesn't scale too well (O(highest_fd)), but its usually |
356 | using this backend. It doesn't scale too well (O(highest_fd)), but its usually |
272 | the fastest backend for a low number of fds. |
357 | the fastest backend for a low number of fds. |
273 | .ie n .IP """EVMETHOD_POLL"" (value 2, poll backend, available everywhere except on windows)" 4 |
358 | .ie n .IP """EVBACKEND_POLL"" (value 2, poll backend, available everywhere except on windows)" 4 |
274 | .el .IP "\f(CWEVMETHOD_POLL\fR (value 2, poll backend, available everywhere except on windows)" 4 |
359 | .el .IP "\f(CWEVBACKEND_POLL\fR (value 2, poll backend, available everywhere except on windows)" 4 |
275 | .IX Item "EVMETHOD_POLL (value 2, poll backend, available everywhere except on windows)" |
360 | .IX Item "EVBACKEND_POLL (value 2, poll backend, available everywhere except on windows)" |
276 | And this is your standard \fIpoll\fR\|(2) backend. It's more complicated than |
361 | And this is your standard \fIpoll\fR\|(2) backend. It's more complicated than |
277 | select, but handles sparse fds better and has no artificial limit on the |
362 | select, but handles sparse fds better and has no artificial limit on the |
278 | number of fds you can use (except it will slow down considerably with a |
363 | number of fds you can use (except it will slow down considerably with a |
279 | lot of inactive fds). It scales similarly to select, i.e. O(total_fds). |
364 | lot of inactive fds). It scales similarly to select, i.e. O(total_fds). |
280 | .ie n .IP """EVMETHOD_EPOLL"" (value 4, Linux)" 4 |
365 | .ie n .IP """EVBACKEND_EPOLL"" (value 4, Linux)" 4 |
281 | .el .IP "\f(CWEVMETHOD_EPOLL\fR (value 4, Linux)" 4 |
366 | .el .IP "\f(CWEVBACKEND_EPOLL\fR (value 4, Linux)" 4 |
282 | .IX Item "EVMETHOD_EPOLL (value 4, Linux)" |
367 | .IX Item "EVBACKEND_EPOLL (value 4, Linux)" |
283 | For few fds, this backend is a bit little slower than poll and select, |
368 | For few fds, this backend is a bit little slower than poll and select, |
284 | but it scales phenomenally better. While poll and select usually scale like |
369 | but it scales phenomenally better. While poll and select usually scale like |
285 | O(total_fds) where n is the total number of fds (or the highest fd), epoll scales |
370 | O(total_fds) where n is the total number of fds (or the highest fd), epoll scales |
286 | either O(1) or O(active_fds). |
371 | either O(1) or O(active_fds). |
287 | .Sp |
372 | .Sp |
288 | While stopping and starting an I/O watcher in the same iteration will |
373 | While stopping and starting an I/O watcher in the same iteration will |
289 | result in some caching, there is still a syscall per such incident |
374 | result in some caching, there is still a syscall per such incident |
290 | (because the fd could point to a different file description now), so its |
375 | (because the fd could point to a different file description now), so its |
291 | best to avoid that. Also, \fIdup()\fRed file descriptors might not work very |
376 | best to avoid that. Also, \fIdup()\fRed file descriptors might not work very |
292 | well if you register events for both fds. |
377 | well if you register events for both fds. |
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378 | .Sp |
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379 | Please note that epoll sometimes generates spurious notifications, so you |
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380 | need to use non-blocking I/O or other means to avoid blocking when no data |
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381 | (or space) is available. |
293 | .ie n .IP """EVMETHOD_KQUEUE"" (value 8, most \s-1BSD\s0 clones)" 4 |
382 | .ie n .IP """EVBACKEND_KQUEUE"" (value 8, most \s-1BSD\s0 clones)" 4 |
294 | .el .IP "\f(CWEVMETHOD_KQUEUE\fR (value 8, most \s-1BSD\s0 clones)" 4 |
383 | .el .IP "\f(CWEVBACKEND_KQUEUE\fR (value 8, most \s-1BSD\s0 clones)" 4 |
295 | .IX Item "EVMETHOD_KQUEUE (value 8, most BSD clones)" |
384 | .IX Item "EVBACKEND_KQUEUE (value 8, most BSD clones)" |
296 | Kqueue deserves special mention, as at the time of this writing, it |
385 | Kqueue deserves special mention, as at the time of this writing, it |
297 | was broken on all BSDs except NetBSD (usually it doesn't work with |
386 | was broken on all BSDs except NetBSD (usually it doesn't work with |
298 | anything but sockets and pipes, except on Darwin, where of course its |
387 | anything but sockets and pipes, except on Darwin, where of course its |
299 | completely useless). For this reason its not being \*(L"autodetected\*(R" unless |
388 | completely useless). For this reason its not being \*(L"autodetected\*(R" |
300 | you explicitly specify the flags (i.e. you don't use \s-1EVFLAG_AUTO\s0). |
389 | unless you explicitly specify it explicitly in the flags (i.e. using |
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390 | \&\f(CW\*(C`EVBACKEND_KQUEUE\*(C'\fR). |
301 | .Sp |
391 | .Sp |
302 | It scales in the same way as the epoll backend, but the interface to the |
392 | It scales in the same way as the epoll backend, but the interface to the |
303 | kernel is more efficient (which says nothing about its actual speed, of |
393 | kernel is more efficient (which says nothing about its actual speed, of |
304 | course). While starting and stopping an I/O watcher does not cause an |
394 | course). While starting and stopping an I/O watcher does not cause an |
305 | extra syscall as with epoll, it still adds up to four event changes per |
395 | extra syscall as with epoll, it still adds up to four event changes per |
306 | incident, so its best to avoid that. |
396 | incident, so its best to avoid that. |
307 | .ie n .IP """EVMETHOD_DEVPOLL"" (value 16, Solaris 8)" 4 |
397 | .ie n .IP """EVBACKEND_DEVPOLL"" (value 16, Solaris 8)" 4 |
308 | .el .IP "\f(CWEVMETHOD_DEVPOLL\fR (value 16, Solaris 8)" 4 |
398 | .el .IP "\f(CWEVBACKEND_DEVPOLL\fR (value 16, Solaris 8)" 4 |
309 | .IX Item "EVMETHOD_DEVPOLL (value 16, Solaris 8)" |
399 | .IX Item "EVBACKEND_DEVPOLL (value 16, Solaris 8)" |
310 | This is not implemented yet (and might never be). |
400 | This is not implemented yet (and might never be). |
311 | .ie n .IP """EVMETHOD_PORT"" (value 32, Solaris 10)" 4 |
401 | .ie n .IP """EVBACKEND_PORT"" (value 32, Solaris 10)" 4 |
312 | .el .IP "\f(CWEVMETHOD_PORT\fR (value 32, Solaris 10)" 4 |
402 | .el .IP "\f(CWEVBACKEND_PORT\fR (value 32, Solaris 10)" 4 |
313 | .IX Item "EVMETHOD_PORT (value 32, Solaris 10)" |
403 | .IX Item "EVBACKEND_PORT (value 32, Solaris 10)" |
314 | This uses the Solaris 10 port mechanism. As with everything on Solaris, |
404 | This uses the Solaris 10 port mechanism. As with everything on Solaris, |
315 | it's really slow, but it still scales very well (O(active_fds)). |
405 | it's really slow, but it still scales very well (O(active_fds)). |
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406 | .Sp |
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407 | Please note that solaris ports can result in a lot of spurious |
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408 | notifications, so you need to use non-blocking I/O or other means to avoid |
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409 | blocking when no data (or space) is available. |
316 | .ie n .IP """EVMETHOD_ALL""" 4 |
410 | .ie n .IP """EVBACKEND_ALL""" 4 |
317 | .el .IP "\f(CWEVMETHOD_ALL\fR" 4 |
411 | .el .IP "\f(CWEVBACKEND_ALL\fR" 4 |
318 | .IX Item "EVMETHOD_ALL" |
412 | .IX Item "EVBACKEND_ALL" |
319 | Try all backends (even potentially broken ones that wouldn't be tried |
413 | Try all backends (even potentially broken ones that wouldn't be tried |
320 | with \f(CW\*(C`EVFLAG_AUTO\*(C'\fR). Since this is a mask, you can do stuff such as |
414 | with \f(CW\*(C`EVFLAG_AUTO\*(C'\fR). Since this is a mask, you can do stuff such as |
321 | \&\f(CW\*(C`EVMETHOD_ALL & ~EVMETHOD_KQUEUE\*(C'\fR. |
415 | \&\f(CW\*(C`EVBACKEND_ALL & ~EVBACKEND_KQUEUE\*(C'\fR. |
322 | .RE |
416 | .RE |
323 | .RS 4 |
417 | .RS 4 |
324 | .Sp |
418 | .Sp |
325 | If one or more of these are ored into the flags value, then only these |
419 | If one or more of these are ored into the flags value, then only these |
326 | backends will be tried (in the reverse order as given here). If none are |
420 | backends will be tried (in the reverse order as given here). If none are |
327 | specified, most compiled-in backend will be tried, usually in reverse |
421 | specified, most compiled-in backend will be tried, usually in reverse |
328 | order of their flag values :) |
422 | order of their flag values :) |
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423 | .Sp |
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424 | The most typical usage is like this: |
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425 | .Sp |
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426 | .Vb 2 |
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427 | \& if (!ev_default_loop (0)) |
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428 | \& fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?"); |
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429 | .Ve |
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430 | .Sp |
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431 | Restrict libev to the select and poll backends, and do not allow |
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432 | environment settings to be taken into account: |
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433 | .Sp |
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434 | .Vb 1 |
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435 | \& ev_default_loop (EVBACKEND_POLL | EVBACKEND_SELECT | EVFLAG_NOENV); |
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436 | .Ve |
|
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437 | .Sp |
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438 | Use whatever libev has to offer, but make sure that kqueue is used if |
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439 | available (warning, breaks stuff, best use only with your own private |
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440 | event loop and only if you know the \s-1OS\s0 supports your types of fds): |
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441 | .Sp |
|
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442 | .Vb 1 |
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443 | \& ev_default_loop (ev_recommended_backends () | EVBACKEND_KQUEUE); |
|
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444 | .Ve |
329 | .RE |
445 | .RE |
330 | .IP "struct ev_loop *ev_loop_new (unsigned int flags)" 4 |
446 | .IP "struct ev_loop *ev_loop_new (unsigned int flags)" 4 |
331 | .IX Item "struct ev_loop *ev_loop_new (unsigned int flags)" |
447 | .IX Item "struct ev_loop *ev_loop_new (unsigned int flags)" |
332 | Similar to \f(CW\*(C`ev_default_loop\*(C'\fR, but always creates a new event loop that is |
448 | Similar to \f(CW\*(C`ev_default_loop\*(C'\fR, but always creates a new event loop that is |
333 | always distinct from the default loop. Unlike the default loop, it cannot |
449 | always distinct from the default loop. Unlike the default loop, it cannot |
334 | handle signal and child watchers, and attempts to do so will be greeted by |
450 | handle signal and child watchers, and attempts to do so will be greeted by |
335 | undefined behaviour (or a failed assertion if assertions are enabled). |
451 | undefined behaviour (or a failed assertion if assertions are enabled). |
|
|
452 | .Sp |
|
|
453 | Example: try to create a event loop that uses epoll and nothing else. |
|
|
454 | .Sp |
|
|
455 | .Vb 3 |
|
|
456 | \& struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
|
|
457 | \& if (!epoller) |
|
|
458 | \& fatal ("no epoll found here, maybe it hides under your chair"); |
|
|
459 | .Ve |
336 | .IP "ev_default_destroy ()" 4 |
460 | .IP "ev_default_destroy ()" 4 |
337 | .IX Item "ev_default_destroy ()" |
461 | .IX Item "ev_default_destroy ()" |
338 | Destroys the default loop again (frees all memory and kernel state |
462 | Destroys the default loop again (frees all memory and kernel state |
339 | etc.). This stops all registered event watchers (by not touching them in |
463 | etc.). None of the active event watchers will be stopped in the normal |
340 | any way whatsoever, although you cannot rely on this :). |
464 | sense, so e.g. \f(CW\*(C`ev_is_active\*(C'\fR might still return true. It is your |
|
|
465 | responsibility to either stop all watchers cleanly yoursef \fIbefore\fR |
|
|
466 | calling this function, or cope with the fact afterwards (which is usually |
|
|
467 | the easiest thing, youc na just ignore the watchers and/or \f(CW\*(C`free ()\*(C'\fR them |
|
|
468 | for example). |
341 | .IP "ev_loop_destroy (loop)" 4 |
469 | .IP "ev_loop_destroy (loop)" 4 |
342 | .IX Item "ev_loop_destroy (loop)" |
470 | .IX Item "ev_loop_destroy (loop)" |
343 | Like \f(CW\*(C`ev_default_destroy\*(C'\fR, but destroys an event loop created by an |
471 | Like \f(CW\*(C`ev_default_destroy\*(C'\fR, but destroys an event loop created by an |
344 | earlier call to \f(CW\*(C`ev_loop_new\*(C'\fR. |
472 | earlier call to \f(CW\*(C`ev_loop_new\*(C'\fR. |
345 | .IP "ev_default_fork ()" 4 |
473 | .IP "ev_default_fork ()" 4 |
… | |
… | |
347 | This function reinitialises the kernel state for backends that have |
475 | This function reinitialises the kernel state for backends that have |
348 | one. Despite the name, you can call it anytime, but it makes most sense |
476 | one. Despite the name, you can call it anytime, but it makes most sense |
349 | after forking, in either the parent or child process (or both, but that |
477 | after forking, in either the parent or child process (or both, but that |
350 | again makes little sense). |
478 | again makes little sense). |
351 | .Sp |
479 | .Sp |
352 | You \fImust\fR call this function after forking if and only if you want to |
480 | You \fImust\fR call this function in the child process after forking if and |
353 | use the event library in both processes. If you just fork+exec, you don't |
481 | only if you want to use the event library in both processes. If you just |
354 | have to call it. |
482 | fork+exec, you don't have to call it. |
355 | .Sp |
483 | .Sp |
356 | The function itself is quite fast and it's usually not a problem to call |
484 | The function itself is quite fast and it's usually not a problem to call |
357 | it just in case after a fork. To make this easy, the function will fit in |
485 | it just in case after a fork. To make this easy, the function will fit in |
358 | quite nicely into a call to \f(CW\*(C`pthread_atfork\*(C'\fR: |
486 | quite nicely into a call to \f(CW\*(C`pthread_atfork\*(C'\fR: |
359 | .Sp |
487 | .Sp |
360 | .Vb 1 |
488 | .Vb 1 |
361 | \& pthread_atfork (0, 0, ev_default_fork); |
489 | \& pthread_atfork (0, 0, ev_default_fork); |
362 | .Ve |
490 | .Ve |
|
|
491 | .Sp |
|
|
492 | At the moment, \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR and \f(CW\*(C`EVBACKEND_POLL\*(C'\fR are safe to use |
|
|
493 | without calling this function, so if you force one of those backends you |
|
|
494 | do not need to care. |
363 | .IP "ev_loop_fork (loop)" 4 |
495 | .IP "ev_loop_fork (loop)" 4 |
364 | .IX Item "ev_loop_fork (loop)" |
496 | .IX Item "ev_loop_fork (loop)" |
365 | Like \f(CW\*(C`ev_default_fork\*(C'\fR, but acts on an event loop created by |
497 | Like \f(CW\*(C`ev_default_fork\*(C'\fR, but acts on an event loop created by |
366 | \&\f(CW\*(C`ev_loop_new\*(C'\fR. Yes, you have to call this on every allocated event loop |
498 | \&\f(CW\*(C`ev_loop_new\*(C'\fR. Yes, you have to call this on every allocated event loop |
367 | after fork, and how you do this is entirely your own problem. |
499 | after fork, and how you do this is entirely your own problem. |
368 | .IP "unsigned int ev_method (loop)" 4 |
500 | .IP "unsigned int ev_backend (loop)" 4 |
369 | .IX Item "unsigned int ev_method (loop)" |
501 | .IX Item "unsigned int ev_backend (loop)" |
370 | Returns one of the \f(CW\*(C`EVMETHOD_*\*(C'\fR flags indicating the event backend in |
502 | Returns one of the \f(CW\*(C`EVBACKEND_*\*(C'\fR flags indicating the event backend in |
371 | use. |
503 | use. |
372 | .IP "ev_tstamp ev_now (loop)" 4 |
504 | .IP "ev_tstamp ev_now (loop)" 4 |
373 | .IX Item "ev_tstamp ev_now (loop)" |
505 | .IX Item "ev_tstamp ev_now (loop)" |
374 | Returns the current \*(L"event loop time\*(R", which is the time the event loop |
506 | Returns the current \*(L"event loop time\*(R", which is the time the event loop |
375 | got events and started processing them. This timestamp does not change |
507 | received events and started processing them. This timestamp does not |
376 | as long as callbacks are being processed, and this is also the base time |
508 | change as long as callbacks are being processed, and this is also the base |
377 | used for relative timers. You can treat it as the timestamp of the event |
509 | time used for relative timers. You can treat it as the timestamp of the |
378 | occuring (or more correctly, the mainloop finding out about it). |
510 | event occuring (or more correctly, libev finding out about it). |
379 | .IP "ev_loop (loop, int flags)" 4 |
511 | .IP "ev_loop (loop, int flags)" 4 |
380 | .IX Item "ev_loop (loop, int flags)" |
512 | .IX Item "ev_loop (loop, int flags)" |
381 | Finally, this is it, the event handler. This function usually is called |
513 | Finally, this is it, the event handler. This function usually is called |
382 | after you initialised all your watchers and you want to start handling |
514 | after you initialised all your watchers and you want to start handling |
383 | events. |
515 | events. |
384 | .Sp |
516 | .Sp |
385 | If the flags argument is specified as 0, it will not return until either |
517 | If the flags argument is specified as \f(CW0\fR, it will not return until |
386 | no event watchers are active anymore or \f(CW\*(C`ev_unloop\*(C'\fR was called. |
518 | either no event watchers are active anymore or \f(CW\*(C`ev_unloop\*(C'\fR was called. |
|
|
519 | .Sp |
|
|
520 | Please note that an explicit \f(CW\*(C`ev_unloop\*(C'\fR is usually better than |
|
|
521 | relying on all watchers to be stopped when deciding when a program has |
|
|
522 | finished (especially in interactive programs), but having a program that |
|
|
523 | automatically loops as long as it has to and no longer by virtue of |
|
|
524 | relying on its watchers stopping correctly is a thing of beauty. |
387 | .Sp |
525 | .Sp |
388 | A flags value of \f(CW\*(C`EVLOOP_NONBLOCK\*(C'\fR will look for new events, will handle |
526 | A flags value of \f(CW\*(C`EVLOOP_NONBLOCK\*(C'\fR will look for new events, will handle |
389 | those events and any outstanding ones, but will not block your process in |
527 | those events and any outstanding ones, but will not block your process in |
390 | case there are no events and will return after one iteration of the loop. |
528 | case there are no events and will return after one iteration of the loop. |
391 | .Sp |
529 | .Sp |
392 | A flags value of \f(CW\*(C`EVLOOP_ONESHOT\*(C'\fR will look for new events (waiting if |
530 | A flags value of \f(CW\*(C`EVLOOP_ONESHOT\*(C'\fR will look for new events (waiting if |
393 | neccessary) and will handle those and any outstanding ones. It will block |
531 | neccessary) and will handle those and any outstanding ones. It will block |
394 | your process until at least one new event arrives, and will return after |
532 | your process until at least one new event arrives, and will return after |
395 | one iteration of the loop. |
533 | one iteration of the loop. This is useful if you are waiting for some |
|
|
534 | external event in conjunction with something not expressible using other |
|
|
535 | libev watchers. However, a pair of \f(CW\*(C`ev_prepare\*(C'\fR/\f(CW\*(C`ev_check\*(C'\fR watchers is |
|
|
536 | usually a better approach for this kind of thing. |
396 | .Sp |
537 | .Sp |
397 | This flags value could be used to implement alternative looping |
|
|
398 | constructs, but the \f(CW\*(C`prepare\*(C'\fR and \f(CW\*(C`check\*(C'\fR watchers provide a better and |
|
|
399 | more generic mechanism. |
|
|
400 | .Sp |
|
|
401 | Here are the gory details of what ev_loop does: |
538 | Here are the gory details of what \f(CW\*(C`ev_loop\*(C'\fR does: |
402 | .Sp |
539 | .Sp |
403 | .Vb 15 |
540 | .Vb 18 |
404 | \& 1. If there are no active watchers (reference count is zero), return. |
541 | \& * If there are no active watchers (reference count is zero), return. |
405 | \& 2. Queue and immediately call all prepare watchers. |
542 | \& - Queue prepare watchers and then call all outstanding watchers. |
406 | \& 3. If we have been forked, recreate the kernel state. |
543 | \& - If we have been forked, recreate the kernel state. |
407 | \& 4. Update the kernel state with all outstanding changes. |
544 | \& - Update the kernel state with all outstanding changes. |
408 | \& 5. Update the "event loop time". |
545 | \& - Update the "event loop time". |
409 | \& 6. Calculate for how long to block. |
546 | \& - Calculate for how long to block. |
410 | \& 7. Block the process, waiting for events. |
547 | \& - Block the process, waiting for any events. |
|
|
548 | \& - Queue all outstanding I/O (fd) events. |
411 | \& 8. Update the "event loop time" and do time jump handling. |
549 | \& - Update the "event loop time" and do time jump handling. |
412 | \& 9. Queue all outstanding timers. |
550 | \& - Queue all outstanding timers. |
413 | \& 10. Queue all outstanding periodics. |
551 | \& - Queue all outstanding periodics. |
414 | \& 11. If no events are pending now, queue all idle watchers. |
552 | \& - If no events are pending now, queue all idle watchers. |
415 | \& 12. Queue all check watchers. |
553 | \& - Queue all check watchers. |
416 | \& 13. Call all queued watchers in reverse order (i.e. check watchers first). |
554 | \& - Call all queued watchers in reverse order (i.e. check watchers first). |
|
|
555 | \& Signals and child watchers are implemented as I/O watchers, and will |
|
|
556 | \& be handled here by queueing them when their watcher gets executed. |
417 | \& 14. If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
557 | \& - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
418 | \& was used, return, otherwise continue with step #1. |
558 | \& were used, return, otherwise continue with step *. |
|
|
559 | .Ve |
|
|
560 | .Sp |
|
|
561 | Example: queue some jobs and then loop until no events are outsanding |
|
|
562 | anymore. |
|
|
563 | .Sp |
|
|
564 | .Vb 4 |
|
|
565 | \& ... queue jobs here, make sure they register event watchers as long |
|
|
566 | \& ... as they still have work to do (even an idle watcher will do..) |
|
|
567 | \& ev_loop (my_loop, 0); |
|
|
568 | \& ... jobs done. yeah! |
419 | .Ve |
569 | .Ve |
420 | .IP "ev_unloop (loop, how)" 4 |
570 | .IP "ev_unloop (loop, how)" 4 |
421 | .IX Item "ev_unloop (loop, how)" |
571 | .IX Item "ev_unloop (loop, how)" |
422 | Can be used to make a call to \f(CW\*(C`ev_loop\*(C'\fR return early (but only after it |
572 | Can be used to make a call to \f(CW\*(C`ev_loop\*(C'\fR return early (but only after it |
423 | has processed all outstanding events). The \f(CW\*(C`how\*(C'\fR argument must be either |
573 | has processed all outstanding events). The \f(CW\*(C`how\*(C'\fR argument must be either |
… | |
… | |
437 | example, libev itself uses this for its internal signal pipe: It is not |
587 | example, libev itself uses this for its internal signal pipe: It is not |
438 | visible to the libev user and should not keep \f(CW\*(C`ev_loop\*(C'\fR from exiting if |
588 | visible to the libev user and should not keep \f(CW\*(C`ev_loop\*(C'\fR from exiting if |
439 | no event watchers registered by it are active. It is also an excellent |
589 | no event watchers registered by it are active. It is also an excellent |
440 | way to do this for generic recurring timers or from within third-party |
590 | way to do this for generic recurring timers or from within third-party |
441 | libraries. Just remember to \fIunref after start\fR and \fIref before stop\fR. |
591 | libraries. Just remember to \fIunref after start\fR and \fIref before stop\fR. |
|
|
592 | .Sp |
|
|
593 | Example: create a signal watcher, but keep it from keeping \f(CW\*(C`ev_loop\*(C'\fR |
|
|
594 | running when nothing else is active. |
|
|
595 | .Sp |
|
|
596 | .Vb 4 |
|
|
597 | \& struct dv_signal exitsig; |
|
|
598 | \& ev_signal_init (&exitsig, sig_cb, SIGINT); |
|
|
599 | \& ev_signal_start (myloop, &exitsig); |
|
|
600 | \& evf_unref (myloop); |
|
|
601 | .Ve |
|
|
602 | .Sp |
|
|
603 | Example: for some weird reason, unregister the above signal handler again. |
|
|
604 | .Sp |
|
|
605 | .Vb 2 |
|
|
606 | \& ev_ref (myloop); |
|
|
607 | \& ev_signal_stop (myloop, &exitsig); |
|
|
608 | .Ve |
442 | .SH "ANATOMY OF A WATCHER" |
609 | .SH "ANATOMY OF A WATCHER" |
443 | .IX Header "ANATOMY OF A WATCHER" |
610 | .IX Header "ANATOMY OF A WATCHER" |
444 | A watcher is a structure that you create and register to record your |
611 | A watcher is a structure that you create and register to record your |
445 | interest in some event. For instance, if you want to wait for \s-1STDIN\s0 to |
612 | interest in some event. For instance, if you want to wait for \s-1STDIN\s0 to |
446 | become readable, you would create an \f(CW\*(C`ev_io\*(C'\fR watcher for that: |
613 | become readable, you would create an \f(CW\*(C`ev_io\*(C'\fR watcher for that: |
… | |
… | |
482 | *)\*(C'\fR), and you can stop watching for events at any time by calling the |
649 | *)\*(C'\fR), and you can stop watching for events at any time by calling the |
483 | corresponding stop function (\f(CW\*(C`ev_<type>_stop (loop, watcher *)\*(C'\fR. |
650 | corresponding stop function (\f(CW\*(C`ev_<type>_stop (loop, watcher *)\*(C'\fR. |
484 | .PP |
651 | .PP |
485 | As long as your watcher is active (has been started but not stopped) you |
652 | As long as your watcher is active (has been started but not stopped) you |
486 | must not touch the values stored in it. Most specifically you must never |
653 | must not touch the values stored in it. Most specifically you must never |
487 | reinitialise it or call its set method. |
654 | reinitialise it or call its \f(CW\*(C`set\*(C'\fR macro. |
488 | .PP |
|
|
489 | You can check whether an event is active by calling the \f(CW\*(C`ev_is_active |
|
|
490 | (watcher *)\*(C'\fR macro. To see whether an event is outstanding (but the |
|
|
491 | callback for it has not been called yet) you can use the \f(CW\*(C`ev_is_pending |
|
|
492 | (watcher *)\*(C'\fR macro. |
|
|
493 | .PP |
655 | .PP |
494 | Each and every callback receives the event loop pointer as first, the |
656 | Each and every callback receives the event loop pointer as first, the |
495 | registered watcher structure as second, and a bitset of received events as |
657 | registered watcher structure as second, and a bitset of received events as |
496 | third argument. |
658 | third argument. |
497 | .PP |
659 | .PP |
… | |
… | |
522 | The signal specified in the \f(CW\*(C`ev_signal\*(C'\fR watcher has been received by a thread. |
684 | The signal specified in the \f(CW\*(C`ev_signal\*(C'\fR watcher has been received by a thread. |
523 | .ie n .IP """EV_CHILD""" 4 |
685 | .ie n .IP """EV_CHILD""" 4 |
524 | .el .IP "\f(CWEV_CHILD\fR" 4 |
686 | .el .IP "\f(CWEV_CHILD\fR" 4 |
525 | .IX Item "EV_CHILD" |
687 | .IX Item "EV_CHILD" |
526 | The pid specified in the \f(CW\*(C`ev_child\*(C'\fR watcher has received a status change. |
688 | The pid specified in the \f(CW\*(C`ev_child\*(C'\fR watcher has received a status change. |
|
|
689 | .ie n .IP """EV_STAT""" 4 |
|
|
690 | .el .IP "\f(CWEV_STAT\fR" 4 |
|
|
691 | .IX Item "EV_STAT" |
|
|
692 | The path specified in the \f(CW\*(C`ev_stat\*(C'\fR watcher changed its attributes somehow. |
527 | .ie n .IP """EV_IDLE""" 4 |
693 | .ie n .IP """EV_IDLE""" 4 |
528 | .el .IP "\f(CWEV_IDLE\fR" 4 |
694 | .el .IP "\f(CWEV_IDLE\fR" 4 |
529 | .IX Item "EV_IDLE" |
695 | .IX Item "EV_IDLE" |
530 | The \f(CW\*(C`ev_idle\*(C'\fR watcher has determined that you have nothing better to do. |
696 | The \f(CW\*(C`ev_idle\*(C'\fR watcher has determined that you have nothing better to do. |
531 | .ie n .IP """EV_PREPARE""" 4 |
697 | .ie n .IP """EV_PREPARE""" 4 |
… | |
… | |
555 | Libev will usually signal a few \*(L"dummy\*(R" events together with an error, |
721 | Libev will usually signal a few \*(L"dummy\*(R" events together with an error, |
556 | for example it might indicate that a fd is readable or writable, and if |
722 | for example it might indicate that a fd is readable or writable, and if |
557 | your callbacks is well-written it can just attempt the operation and cope |
723 | your callbacks is well-written it can just attempt the operation and cope |
558 | with the error from \fIread()\fR or \fIwrite()\fR. This will not work in multithreaded |
724 | with the error from \fIread()\fR or \fIwrite()\fR. This will not work in multithreaded |
559 | programs, though, so beware. |
725 | programs, though, so beware. |
|
|
726 | .Sh "\s-1GENERIC\s0 \s-1WATCHER\s0 \s-1FUNCTIONS\s0" |
|
|
727 | .IX Subsection "GENERIC WATCHER FUNCTIONS" |
|
|
728 | In the following description, \f(CW\*(C`TYPE\*(C'\fR stands for the watcher type, |
|
|
729 | e.g. \f(CW\*(C`timer\*(C'\fR for \f(CW\*(C`ev_timer\*(C'\fR watchers and \f(CW\*(C`io\*(C'\fR for \f(CW\*(C`ev_io\*(C'\fR watchers. |
|
|
730 | .ie n .IP """ev_init"" (ev_TYPE *watcher, callback)" 4 |
|
|
731 | .el .IP "\f(CWev_init\fR (ev_TYPE *watcher, callback)" 4 |
|
|
732 | .IX Item "ev_init (ev_TYPE *watcher, callback)" |
|
|
733 | This macro initialises the generic portion of a watcher. The contents |
|
|
734 | of the watcher object can be arbitrary (so \f(CW\*(C`malloc\*(C'\fR will do). Only |
|
|
735 | the generic parts of the watcher are initialised, you \fIneed\fR to call |
|
|
736 | the type-specific \f(CW\*(C`ev_TYPE_set\*(C'\fR macro afterwards to initialise the |
|
|
737 | type-specific parts. For each type there is also a \f(CW\*(C`ev_TYPE_init\*(C'\fR macro |
|
|
738 | which rolls both calls into one. |
|
|
739 | .Sp |
|
|
740 | You can reinitialise a watcher at any time as long as it has been stopped |
|
|
741 | (or never started) and there are no pending events outstanding. |
|
|
742 | .Sp |
|
|
743 | The callback is always of type \f(CW\*(C`void (*)(ev_loop *loop, ev_TYPE *watcher, |
|
|
744 | int revents)\*(C'\fR. |
|
|
745 | .ie n .IP """ev_TYPE_set"" (ev_TYPE *, [args])" 4 |
|
|
746 | .el .IP "\f(CWev_TYPE_set\fR (ev_TYPE *, [args])" 4 |
|
|
747 | .IX Item "ev_TYPE_set (ev_TYPE *, [args])" |
|
|
748 | This macro initialises the type-specific parts of a watcher. You need to |
|
|
749 | call \f(CW\*(C`ev_init\*(C'\fR at least once before you call this macro, but you can |
|
|
750 | call \f(CW\*(C`ev_TYPE_set\*(C'\fR any number of times. You must not, however, call this |
|
|
751 | macro on a watcher that is active (it can be pending, however, which is a |
|
|
752 | difference to the \f(CW\*(C`ev_init\*(C'\fR macro). |
|
|
753 | .Sp |
|
|
754 | Although some watcher types do not have type-specific arguments |
|
|
755 | (e.g. \f(CW\*(C`ev_prepare\*(C'\fR) you still need to call its \f(CW\*(C`set\*(C'\fR macro. |
|
|
756 | .ie n .IP """ev_TYPE_init"" (ev_TYPE *watcher, callback, [args])" 4 |
|
|
757 | .el .IP "\f(CWev_TYPE_init\fR (ev_TYPE *watcher, callback, [args])" 4 |
|
|
758 | .IX Item "ev_TYPE_init (ev_TYPE *watcher, callback, [args])" |
|
|
759 | This convinience macro rolls both \f(CW\*(C`ev_init\*(C'\fR and \f(CW\*(C`ev_TYPE_set\*(C'\fR macro |
|
|
760 | calls into a single call. This is the most convinient method to initialise |
|
|
761 | a watcher. The same limitations apply, of course. |
|
|
762 | .ie n .IP """ev_TYPE_start"" (loop *, ev_TYPE *watcher)" 4 |
|
|
763 | .el .IP "\f(CWev_TYPE_start\fR (loop *, ev_TYPE *watcher)" 4 |
|
|
764 | .IX Item "ev_TYPE_start (loop *, ev_TYPE *watcher)" |
|
|
765 | Starts (activates) the given watcher. Only active watchers will receive |
|
|
766 | events. If the watcher is already active nothing will happen. |
|
|
767 | .ie n .IP """ev_TYPE_stop"" (loop *, ev_TYPE *watcher)" 4 |
|
|
768 | .el .IP "\f(CWev_TYPE_stop\fR (loop *, ev_TYPE *watcher)" 4 |
|
|
769 | .IX Item "ev_TYPE_stop (loop *, ev_TYPE *watcher)" |
|
|
770 | Stops the given watcher again (if active) and clears the pending |
|
|
771 | status. It is possible that stopped watchers are pending (for example, |
|
|
772 | non-repeating timers are being stopped when they become pending), but |
|
|
773 | \&\f(CW\*(C`ev_TYPE_stop\*(C'\fR ensures that the watcher is neither active nor pending. If |
|
|
774 | you want to free or reuse the memory used by the watcher it is therefore a |
|
|
775 | good idea to always call its \f(CW\*(C`ev_TYPE_stop\*(C'\fR function. |
|
|
776 | .IP "bool ev_is_active (ev_TYPE *watcher)" 4 |
|
|
777 | .IX Item "bool ev_is_active (ev_TYPE *watcher)" |
|
|
778 | Returns a true value iff the watcher is active (i.e. it has been started |
|
|
779 | and not yet been stopped). As long as a watcher is active you must not modify |
|
|
780 | it. |
|
|
781 | .IP "bool ev_is_pending (ev_TYPE *watcher)" 4 |
|
|
782 | .IX Item "bool ev_is_pending (ev_TYPE *watcher)" |
|
|
783 | Returns a true value iff the watcher is pending, (i.e. it has outstanding |
|
|
784 | events but its callback has not yet been invoked). As long as a watcher |
|
|
785 | is pending (but not active) you must not call an init function on it (but |
|
|
786 | \&\f(CW\*(C`ev_TYPE_set\*(C'\fR is safe) and you must make sure the watcher is available to |
|
|
787 | libev (e.g. you cnanot \f(CW\*(C`free ()\*(C'\fR it). |
|
|
788 | .IP "callback = ev_cb (ev_TYPE *watcher)" 4 |
|
|
789 | .IX Item "callback = ev_cb (ev_TYPE *watcher)" |
|
|
790 | Returns the callback currently set on the watcher. |
|
|
791 | .IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 |
|
|
792 | .IX Item "ev_cb_set (ev_TYPE *watcher, callback)" |
|
|
793 | Change the callback. You can change the callback at virtually any time |
|
|
794 | (modulo threads). |
560 | .Sh "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0" |
795 | .Sh "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0" |
561 | .IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER" |
796 | .IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER" |
562 | Each watcher has, by default, a member \f(CW\*(C`void *data\*(C'\fR that you can change |
797 | Each watcher has, by default, a member \f(CW\*(C`void *data\*(C'\fR that you can change |
563 | and read at any time, libev will completely ignore it. This can be used |
798 | and read at any time, libev will completely ignore it. This can be used |
564 | to associate arbitrary data with your watcher. If you need more data and |
799 | to associate arbitrary data with your watcher. If you need more data and |
… | |
… | |
590 | More interesting and less C\-conformant ways of catsing your callback type |
825 | More interesting and less C\-conformant ways of catsing your callback type |
591 | have been omitted.... |
826 | have been omitted.... |
592 | .SH "WATCHER TYPES" |
827 | .SH "WATCHER TYPES" |
593 | .IX Header "WATCHER TYPES" |
828 | .IX Header "WATCHER TYPES" |
594 | This section describes each watcher in detail, but will not repeat |
829 | This section describes each watcher in detail, but will not repeat |
595 | information given in the last section. |
830 | information given in the last section. Any initialisation/set macros, |
|
|
831 | functions and members specific to the watcher type are explained. |
|
|
832 | .PP |
|
|
833 | Members are additionally marked with either \fI[read\-only]\fR, meaning that, |
|
|
834 | while the watcher is active, you can look at the member and expect some |
|
|
835 | sensible content, but you must not modify it (you can modify it while the |
|
|
836 | watcher is stopped to your hearts content), or \fI[read\-write]\fR, which |
|
|
837 | means you can expect it to have some sensible content while the watcher |
|
|
838 | is active, but you can also modify it. Modifying it may not do something |
|
|
839 | sensible or take immediate effect (or do anything at all), but libev will |
|
|
840 | not crash or malfunction in any way. |
596 | .ie n .Sh """ev_io"" \- is this file descriptor readable or writable" |
841 | .ie n .Sh """ev_io"" \- is this file descriptor readable or writable?" |
597 | .el .Sh "\f(CWev_io\fP \- is this file descriptor readable or writable" |
842 | .el .Sh "\f(CWev_io\fP \- is this file descriptor readable or writable?" |
598 | .IX Subsection "ev_io - is this file descriptor readable or writable" |
843 | .IX Subsection "ev_io - is this file descriptor readable or writable?" |
599 | I/O watchers check whether a file descriptor is readable or writable |
844 | I/O watchers check whether a file descriptor is readable or writable |
600 | in each iteration of the event loop (This behaviour is called |
845 | in each iteration of the event loop, or, more precisely, when reading |
601 | level-triggering because you keep receiving events as long as the |
846 | would not block the process and writing would at least be able to write |
602 | condition persists. Remember you can stop the watcher if you don't want to |
847 | some data. This behaviour is called level-triggering because you keep |
603 | act on the event and neither want to receive future events). |
848 | receiving events as long as the condition persists. Remember you can stop |
|
|
849 | the watcher if you don't want to act on the event and neither want to |
|
|
850 | receive future events. |
604 | .PP |
851 | .PP |
605 | In general you can register as many read and/or write event watchers per |
852 | In general you can register as many read and/or write event watchers per |
606 | fd as you want (as long as you don't confuse yourself). Setting all file |
853 | fd as you want (as long as you don't confuse yourself). Setting all file |
607 | descriptors to non-blocking mode is also usually a good idea (but not |
854 | descriptors to non-blocking mode is also usually a good idea (but not |
608 | required if you know what you are doing). |
855 | required if you know what you are doing). |
609 | .PP |
856 | .PP |
610 | You have to be careful with dup'ed file descriptors, though. Some backends |
857 | You have to be careful with dup'ed file descriptors, though. Some backends |
611 | (the linux epoll backend is a notable example) cannot handle dup'ed file |
858 | (the linux epoll backend is a notable example) cannot handle dup'ed file |
612 | descriptors correctly if you register interest in two or more fds pointing |
859 | descriptors correctly if you register interest in two or more fds pointing |
613 | to the same underlying file/socket etc. description (that is, they share |
860 | to the same underlying file/socket/etc. description (that is, they share |
614 | the same underlying \*(L"file open\*(R"). |
861 | the same underlying \*(L"file open\*(R"). |
615 | .PP |
862 | .PP |
616 | If you must do this, then force the use of a known-to-be-good backend |
863 | If you must do this, then force the use of a known-to-be-good backend |
617 | (at the time of this writing, this includes only \s-1EVMETHOD_SELECT\s0 and |
864 | (at the time of this writing, this includes only \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR and |
618 | \&\s-1EVMETHOD_POLL\s0). |
865 | \&\f(CW\*(C`EVBACKEND_POLL\*(C'\fR). |
|
|
866 | .PP |
|
|
867 | Another thing you have to watch out for is that it is quite easy to |
|
|
868 | receive \*(L"spurious\*(R" readyness notifications, that is your callback might |
|
|
869 | be called with \f(CW\*(C`EV_READ\*(C'\fR but a subsequent \f(CW\*(C`read\*(C'\fR(2) will actually block |
|
|
870 | because there is no data. Not only are some backends known to create a |
|
|
871 | lot of those (for example solaris ports), it is very easy to get into |
|
|
872 | this situation even with a relatively standard program structure. Thus |
|
|
873 | it is best to always use non-blocking I/O: An extra \f(CW\*(C`read\*(C'\fR(2) returning |
|
|
874 | \&\f(CW\*(C`EAGAIN\*(C'\fR is far preferable to a program hanging until some data arrives. |
|
|
875 | .PP |
|
|
876 | If you cannot run the fd in non-blocking mode (for example you should not |
|
|
877 | play around with an Xlib connection), then you have to seperately re-test |
|
|
878 | wether a file descriptor is really ready with a known-to-be good interface |
|
|
879 | such as poll (fortunately in our Xlib example, Xlib already does this on |
|
|
880 | its own, so its quite safe to use). |
619 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
881 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
620 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
882 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
621 | .PD 0 |
883 | .PD 0 |
622 | .IP "ev_io_set (ev_io *, int fd, int events)" 4 |
884 | .IP "ev_io_set (ev_io *, int fd, int events)" 4 |
623 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
885 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
624 | .PD |
886 | .PD |
625 | Configures an \f(CW\*(C`ev_io\*(C'\fR watcher. The fd is the file descriptor to rceeive |
887 | Configures an \f(CW\*(C`ev_io\*(C'\fR watcher. The \f(CW\*(C`fd\*(C'\fR is the file descriptor to |
626 | events for and events is either \f(CW\*(C`EV_READ\*(C'\fR, \f(CW\*(C`EV_WRITE\*(C'\fR or \f(CW\*(C`EV_READ | |
888 | rceeive events for and events is either \f(CW\*(C`EV_READ\*(C'\fR, \f(CW\*(C`EV_WRITE\*(C'\fR or |
627 | EV_WRITE\*(C'\fR to receive the given events. |
889 | \&\f(CW\*(C`EV_READ | EV_WRITE\*(C'\fR to receive the given events. |
|
|
890 | .IP "int fd [read\-only]" 4 |
|
|
891 | .IX Item "int fd [read-only]" |
|
|
892 | The file descriptor being watched. |
|
|
893 | .IP "int events [read\-only]" 4 |
|
|
894 | .IX Item "int events [read-only]" |
|
|
895 | The events being watched. |
|
|
896 | .PP |
|
|
897 | Example: call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well |
|
|
898 | readable, but only once. Since it is likely line\-buffered, you could |
|
|
899 | attempt to read a whole line in the callback: |
|
|
900 | .PP |
|
|
901 | .Vb 6 |
|
|
902 | \& static void |
|
|
903 | \& stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
|
|
904 | \& { |
|
|
905 | \& ev_io_stop (loop, w); |
|
|
906 | \& .. read from stdin here (or from w->fd) and haqndle any I/O errors |
|
|
907 | \& } |
|
|
908 | .Ve |
|
|
909 | .PP |
|
|
910 | .Vb 6 |
|
|
911 | \& ... |
|
|
912 | \& struct ev_loop *loop = ev_default_init (0); |
|
|
913 | \& struct ev_io stdin_readable; |
|
|
914 | \& ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ); |
|
|
915 | \& ev_io_start (loop, &stdin_readable); |
|
|
916 | \& ev_loop (loop, 0); |
|
|
917 | .Ve |
628 | .ie n .Sh """ev_timer"" \- relative and optionally recurring timeouts" |
918 | .ie n .Sh """ev_timer"" \- relative and optionally repeating timeouts" |
629 | .el .Sh "\f(CWev_timer\fP \- relative and optionally recurring timeouts" |
919 | .el .Sh "\f(CWev_timer\fP \- relative and optionally repeating timeouts" |
630 | .IX Subsection "ev_timer - relative and optionally recurring timeouts" |
920 | .IX Subsection "ev_timer - relative and optionally repeating timeouts" |
631 | Timer watchers are simple relative timers that generate an event after a |
921 | Timer watchers are simple relative timers that generate an event after a |
632 | given time, and optionally repeating in regular intervals after that. |
922 | given time, and optionally repeating in regular intervals after that. |
633 | .PP |
923 | .PP |
634 | The timers are based on real time, that is, if you register an event that |
924 | The timers are based on real time, that is, if you register an event that |
635 | times out after an hour and you reset your system clock to last years |
925 | times out after an hour and you reset your system clock to last years |
… | |
… | |
675 | .Sp |
965 | .Sp |
676 | If the timer is repeating, either start it if necessary (with the repeat |
966 | If the timer is repeating, either start it if necessary (with the repeat |
677 | value), or reset the running timer to the repeat value. |
967 | value), or reset the running timer to the repeat value. |
678 | .Sp |
968 | .Sp |
679 | This sounds a bit complicated, but here is a useful and typical |
969 | This sounds a bit complicated, but here is a useful and typical |
680 | example: Imagine you have a tcp connection and you want a so-called idle |
970 | example: Imagine you have a tcp connection and you want a so-called |
681 | timeout, that is, you want to be called when there have been, say, 60 |
971 | idle timeout, that is, you want to be called when there have been, |
682 | seconds of inactivity on the socket. The easiest way to do this is to |
972 | say, 60 seconds of inactivity on the socket. The easiest way to do |
683 | configure an \f(CW\*(C`ev_timer\*(C'\fR with after=repeat=60 and calling ev_timer_again each |
973 | this is to configure an \f(CW\*(C`ev_timer\*(C'\fR with \f(CW\*(C`after\*(C'\fR=\f(CW\*(C`repeat\*(C'\fR=\f(CW60\fR and calling |
684 | time you successfully read or write some data. If you go into an idle |
974 | \&\f(CW\*(C`ev_timer_again\*(C'\fR each time you successfully read or write some data. If |
685 | state where you do not expect data to travel on the socket, you can stop |
975 | you go into an idle state where you do not expect data to travel on the |
686 | the timer, and again will automatically restart it if need be. |
976 | socket, you can stop the timer, and again will automatically restart it if |
|
|
977 | need be. |
|
|
978 | .Sp |
|
|
979 | You can also ignore the \f(CW\*(C`after\*(C'\fR value and \f(CW\*(C`ev_timer_start\*(C'\fR altogether |
|
|
980 | and only ever use the \f(CW\*(C`repeat\*(C'\fR value: |
|
|
981 | .Sp |
|
|
982 | .Vb 8 |
|
|
983 | \& ev_timer_init (timer, callback, 0., 5.); |
|
|
984 | \& ev_timer_again (loop, timer); |
|
|
985 | \& ... |
|
|
986 | \& timer->again = 17.; |
|
|
987 | \& ev_timer_again (loop, timer); |
|
|
988 | \& ... |
|
|
989 | \& timer->again = 10.; |
|
|
990 | \& ev_timer_again (loop, timer); |
|
|
991 | .Ve |
|
|
992 | .Sp |
|
|
993 | This is more efficient then stopping/starting the timer eahc time you want |
|
|
994 | to modify its timeout value. |
|
|
995 | .IP "ev_tstamp repeat [read\-write]" 4 |
|
|
996 | .IX Item "ev_tstamp repeat [read-write]" |
|
|
997 | The current \f(CW\*(C`repeat\*(C'\fR value. Will be used each time the watcher times out |
|
|
998 | or \f(CW\*(C`ev_timer_again\*(C'\fR is called and determines the next timeout (if any), |
|
|
999 | which is also when any modifications are taken into account. |
|
|
1000 | .PP |
|
|
1001 | Example: create a timer that fires after 60 seconds. |
|
|
1002 | .PP |
|
|
1003 | .Vb 5 |
|
|
1004 | \& static void |
|
|
1005 | \& one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
|
|
1006 | \& { |
|
|
1007 | \& .. one minute over, w is actually stopped right here |
|
|
1008 | \& } |
|
|
1009 | .Ve |
|
|
1010 | .PP |
|
|
1011 | .Vb 3 |
|
|
1012 | \& struct ev_timer mytimer; |
|
|
1013 | \& ev_timer_init (&mytimer, one_minute_cb, 60., 0.); |
|
|
1014 | \& ev_timer_start (loop, &mytimer); |
|
|
1015 | .Ve |
|
|
1016 | .PP |
|
|
1017 | Example: create a timeout timer that times out after 10 seconds of |
|
|
1018 | inactivity. |
|
|
1019 | .PP |
|
|
1020 | .Vb 5 |
|
|
1021 | \& static void |
|
|
1022 | \& timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
|
|
1023 | \& { |
|
|
1024 | \& .. ten seconds without any activity |
|
|
1025 | \& } |
|
|
1026 | .Ve |
|
|
1027 | .PP |
|
|
1028 | .Vb 4 |
|
|
1029 | \& struct ev_timer mytimer; |
|
|
1030 | \& ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */ |
|
|
1031 | \& ev_timer_again (&mytimer); /* start timer */ |
|
|
1032 | \& ev_loop (loop, 0); |
|
|
1033 | .Ve |
|
|
1034 | .PP |
|
|
1035 | .Vb 3 |
|
|
1036 | \& // and in some piece of code that gets executed on any "activity": |
|
|
1037 | \& // reset the timeout to start ticking again at 10 seconds |
|
|
1038 | \& ev_timer_again (&mytimer); |
|
|
1039 | .Ve |
687 | .ie n .Sh """ev_periodic"" \- to cron or not to cron" |
1040 | .ie n .Sh """ev_periodic"" \- to cron or not to cron?" |
688 | .el .Sh "\f(CWev_periodic\fP \- to cron or not to cron" |
1041 | .el .Sh "\f(CWev_periodic\fP \- to cron or not to cron?" |
689 | .IX Subsection "ev_periodic - to cron or not to cron" |
1042 | .IX Subsection "ev_periodic - to cron or not to cron?" |
690 | Periodic watchers are also timers of a kind, but they are very versatile |
1043 | Periodic watchers are also timers of a kind, but they are very versatile |
691 | (and unfortunately a bit complex). |
1044 | (and unfortunately a bit complex). |
692 | .PP |
1045 | .PP |
693 | Unlike \f(CW\*(C`ev_timer\*(C'\fR's, they are not based on real time (or relative time) |
1046 | Unlike \f(CW\*(C`ev_timer\*(C'\fR's, they are not based on real time (or relative time) |
694 | but on wallclock time (absolute time). You can tell a periodic watcher |
1047 | but on wallclock time (absolute time). You can tell a periodic watcher |
695 | to trigger \*(L"at\*(R" some specific point in time. For example, if you tell a |
1048 | to trigger \*(L"at\*(R" some specific point in time. For example, if you tell a |
696 | periodic watcher to trigger in 10 seconds (by specifiying e.g. c<ev_now () |
1049 | periodic watcher to trigger in 10 seconds (by specifiying e.g. \f(CW\*(C`ev_now () |
697 | + 10.>) and then reset your system clock to the last year, then it will |
1050 | + 10.\*(C'\fR) and then reset your system clock to the last year, then it will |
698 | take a year to trigger the event (unlike an \f(CW\*(C`ev_timer\*(C'\fR, which would trigger |
1051 | take a year to trigger the event (unlike an \f(CW\*(C`ev_timer\*(C'\fR, which would trigger |
699 | roughly 10 seconds later and of course not if you reset your system time |
1052 | roughly 10 seconds later and of course not if you reset your system time |
700 | again). |
1053 | again). |
701 | .PP |
1054 | .PP |
702 | They can also be used to implement vastly more complex timers, such as |
1055 | They can also be used to implement vastly more complex timers, such as |
… | |
… | |
783 | .IX Item "ev_periodic_again (loop, ev_periodic *)" |
1136 | .IX Item "ev_periodic_again (loop, ev_periodic *)" |
784 | Simply stops and restarts the periodic watcher again. This is only useful |
1137 | Simply stops and restarts the periodic watcher again. This is only useful |
785 | when you changed some parameters or the reschedule callback would return |
1138 | when you changed some parameters or the reschedule callback would return |
786 | a different time than the last time it was called (e.g. in a crond like |
1139 | a different time than the last time it was called (e.g. in a crond like |
787 | program when the crontabs have changed). |
1140 | program when the crontabs have changed). |
|
|
1141 | .IP "ev_tstamp interval [read\-write]" 4 |
|
|
1142 | .IX Item "ev_tstamp interval [read-write]" |
|
|
1143 | The current interval value. Can be modified any time, but changes only |
|
|
1144 | take effect when the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being |
|
|
1145 | called. |
|
|
1146 | .IP "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read\-write]" 4 |
|
|
1147 | .IX Item "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write]" |
|
|
1148 | The current reschedule callback, or \f(CW0\fR, if this functionality is |
|
|
1149 | switched off. Can be changed any time, but changes only take effect when |
|
|
1150 | the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called. |
|
|
1151 | .PP |
|
|
1152 | Example: call a callback every hour, or, more precisely, whenever the |
|
|
1153 | system clock is divisible by 3600. The callback invocation times have |
|
|
1154 | potentially a lot of jittering, but good long-term stability. |
|
|
1155 | .PP |
|
|
1156 | .Vb 5 |
|
|
1157 | \& static void |
|
|
1158 | \& clock_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
|
|
1159 | \& { |
|
|
1160 | \& ... its now a full hour (UTC, or TAI or whatever your clock follows) |
|
|
1161 | \& } |
|
|
1162 | .Ve |
|
|
1163 | .PP |
|
|
1164 | .Vb 3 |
|
|
1165 | \& struct ev_periodic hourly_tick; |
|
|
1166 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); |
|
|
1167 | \& ev_periodic_start (loop, &hourly_tick); |
|
|
1168 | .Ve |
|
|
1169 | .PP |
|
|
1170 | Example: the same as above, but use a reschedule callback to do it: |
|
|
1171 | .PP |
|
|
1172 | .Vb 1 |
|
|
1173 | \& #include <math.h> |
|
|
1174 | .Ve |
|
|
1175 | .PP |
|
|
1176 | .Vb 5 |
|
|
1177 | \& static ev_tstamp |
|
|
1178 | \& my_scheduler_cb (struct ev_periodic *w, ev_tstamp now) |
|
|
1179 | \& { |
|
|
1180 | \& return fmod (now, 3600.) + 3600.; |
|
|
1181 | \& } |
|
|
1182 | .Ve |
|
|
1183 | .PP |
|
|
1184 | .Vb 1 |
|
|
1185 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); |
|
|
1186 | .Ve |
|
|
1187 | .PP |
|
|
1188 | Example: call a callback every hour, starting now: |
|
|
1189 | .PP |
|
|
1190 | .Vb 4 |
|
|
1191 | \& struct ev_periodic hourly_tick; |
|
|
1192 | \& ev_periodic_init (&hourly_tick, clock_cb, |
|
|
1193 | \& fmod (ev_now (loop), 3600.), 3600., 0); |
|
|
1194 | \& ev_periodic_start (loop, &hourly_tick); |
|
|
1195 | .Ve |
788 | .ie n .Sh """ev_signal"" \- signal me when a signal gets signalled" |
1196 | .ie n .Sh """ev_signal"" \- signal me when a signal gets signalled!" |
789 | .el .Sh "\f(CWev_signal\fP \- signal me when a signal gets signalled" |
1197 | .el .Sh "\f(CWev_signal\fP \- signal me when a signal gets signalled!" |
790 | .IX Subsection "ev_signal - signal me when a signal gets signalled" |
1198 | .IX Subsection "ev_signal - signal me when a signal gets signalled!" |
791 | Signal watchers will trigger an event when the process receives a specific |
1199 | Signal watchers will trigger an event when the process receives a specific |
792 | signal one or more times. Even though signals are very asynchronous, libev |
1200 | signal one or more times. Even though signals are very asynchronous, libev |
793 | will try it's best to deliver signals synchronously, i.e. as part of the |
1201 | will try it's best to deliver signals synchronously, i.e. as part of the |
794 | normal event processing, like any other event. |
1202 | normal event processing, like any other event. |
795 | .PP |
1203 | .PP |
… | |
… | |
805 | .IP "ev_signal_set (ev_signal *, int signum)" 4 |
1213 | .IP "ev_signal_set (ev_signal *, int signum)" 4 |
806 | .IX Item "ev_signal_set (ev_signal *, int signum)" |
1214 | .IX Item "ev_signal_set (ev_signal *, int signum)" |
807 | .PD |
1215 | .PD |
808 | Configures the watcher to trigger on the given signal number (usually one |
1216 | Configures the watcher to trigger on the given signal number (usually one |
809 | of the \f(CW\*(C`SIGxxx\*(C'\fR constants). |
1217 | of the \f(CW\*(C`SIGxxx\*(C'\fR constants). |
|
|
1218 | .IP "int signum [read\-only]" 4 |
|
|
1219 | .IX Item "int signum [read-only]" |
|
|
1220 | The signal the watcher watches out for. |
810 | .ie n .Sh """ev_child"" \- wait for pid status changes" |
1221 | .ie n .Sh """ev_child"" \- watch out for process status changes" |
811 | .el .Sh "\f(CWev_child\fP \- wait for pid status changes" |
1222 | .el .Sh "\f(CWev_child\fP \- watch out for process status changes" |
812 | .IX Subsection "ev_child - wait for pid status changes" |
1223 | .IX Subsection "ev_child - watch out for process status changes" |
813 | Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to |
1224 | Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to |
814 | some child status changes (most typically when a child of yours dies). |
1225 | some child status changes (most typically when a child of yours dies). |
815 | .IP "ev_child_init (ev_child *, callback, int pid)" 4 |
1226 | .IP "ev_child_init (ev_child *, callback, int pid)" 4 |
816 | .IX Item "ev_child_init (ev_child *, callback, int pid)" |
1227 | .IX Item "ev_child_init (ev_child *, callback, int pid)" |
817 | .PD 0 |
1228 | .PD 0 |
… | |
… | |
822 | \&\fIany\fR process if \f(CW\*(C`pid\*(C'\fR is specified as \f(CW0\fR). The callback can look |
1233 | \&\fIany\fR process if \f(CW\*(C`pid\*(C'\fR is specified as \f(CW0\fR). The callback can look |
823 | at the \f(CW\*(C`rstatus\*(C'\fR member of the \f(CW\*(C`ev_child\*(C'\fR watcher structure to see |
1234 | at the \f(CW\*(C`rstatus\*(C'\fR member of the \f(CW\*(C`ev_child\*(C'\fR watcher structure to see |
824 | the status word (use the macros from \f(CW\*(C`sys/wait.h\*(C'\fR and see your systems |
1235 | the status word (use the macros from \f(CW\*(C`sys/wait.h\*(C'\fR and see your systems |
825 | \&\f(CW\*(C`waitpid\*(C'\fR documentation). The \f(CW\*(C`rpid\*(C'\fR member contains the pid of the |
1236 | \&\f(CW\*(C`waitpid\*(C'\fR documentation). The \f(CW\*(C`rpid\*(C'\fR member contains the pid of the |
826 | process causing the status change. |
1237 | process causing the status change. |
|
|
1238 | .IP "int pid [read\-only]" 4 |
|
|
1239 | .IX Item "int pid [read-only]" |
|
|
1240 | The process id this watcher watches out for, or \f(CW0\fR, meaning any process id. |
|
|
1241 | .IP "int rpid [read\-write]" 4 |
|
|
1242 | .IX Item "int rpid [read-write]" |
|
|
1243 | The process id that detected a status change. |
|
|
1244 | .IP "int rstatus [read\-write]" 4 |
|
|
1245 | .IX Item "int rstatus [read-write]" |
|
|
1246 | The process exit/trace status caused by \f(CW\*(C`rpid\*(C'\fR (see your systems |
|
|
1247 | \&\f(CW\*(C`waitpid\*(C'\fR and \f(CW\*(C`sys/wait.h\*(C'\fR documentation for details). |
|
|
1248 | .PP |
|
|
1249 | Example: try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0. |
|
|
1250 | .PP |
|
|
1251 | .Vb 5 |
|
|
1252 | \& static void |
|
|
1253 | \& sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
|
|
1254 | \& { |
|
|
1255 | \& ev_unloop (loop, EVUNLOOP_ALL); |
|
|
1256 | \& } |
|
|
1257 | .Ve |
|
|
1258 | .PP |
|
|
1259 | .Vb 3 |
|
|
1260 | \& struct ev_signal signal_watcher; |
|
|
1261 | \& ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
|
|
1262 | \& ev_signal_start (loop, &sigint_cb); |
|
|
1263 | .Ve |
|
|
1264 | .ie n .Sh """ev_stat"" \- did the file attributes just change?" |
|
|
1265 | .el .Sh "\f(CWev_stat\fP \- did the file attributes just change?" |
|
|
1266 | .IX Subsection "ev_stat - did the file attributes just change?" |
|
|
1267 | This watches a filesystem path for attribute changes. That is, it calls |
|
|
1268 | \&\f(CW\*(C`stat\*(C'\fR regularly (or when the \s-1OS\s0 says it changed) and sees if it changed |
|
|
1269 | compared to the last time, invoking the callback if it did. |
|
|
1270 | .PP |
|
|
1271 | The path does not need to exist: changing from \*(L"path exists\*(R" to \*(L"path does |
|
|
1272 | not exist\*(R" is a status change like any other. The condition \*(L"path does |
|
|
1273 | not exist\*(R" is signified by the \f(CW\*(C`st_nlink\*(C'\fR field being zero (which is |
|
|
1274 | otherwise always forced to be at least one) and all the other fields of |
|
|
1275 | the stat buffer having unspecified contents. |
|
|
1276 | .PP |
|
|
1277 | Since there is no standard to do this, the portable implementation simply |
|
|
1278 | calls \f(CW\*(C`stat (2)\*(C'\fR regulalry on the path to see if it changed somehow. You |
|
|
1279 | can specify a recommended polling interval for this case. If you specify |
|
|
1280 | a polling interval of \f(CW0\fR (highly recommended!) then a \fIsuitable, |
|
|
1281 | unspecified default\fR value will be used (which you can expect to be around |
|
|
1282 | five seconds, although this might change dynamically). Libev will also |
|
|
1283 | impose a minimum interval which is currently around \f(CW0.1\fR, but thats |
|
|
1284 | usually overkill. |
|
|
1285 | .PP |
|
|
1286 | This watcher type is not meant for massive numbers of stat watchers, |
|
|
1287 | as even with OS-supported change notifications, this can be |
|
|
1288 | resource\-intensive. |
|
|
1289 | .PP |
|
|
1290 | At the time of this writing, no specific \s-1OS\s0 backends are implemented, but |
|
|
1291 | if demand increases, at least a kqueue and inotify backend will be added. |
|
|
1292 | .IP "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" 4 |
|
|
1293 | .IX Item "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" |
|
|
1294 | .PD 0 |
|
|
1295 | .IP "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" 4 |
|
|
1296 | .IX Item "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" |
|
|
1297 | .PD |
|
|
1298 | Configures the watcher to wait for status changes of the given |
|
|
1299 | \&\f(CW\*(C`path\*(C'\fR. The \f(CW\*(C`interval\*(C'\fR is a hint on how quickly a change is expected to |
|
|
1300 | be detected and should normally be specified as \f(CW0\fR to let libev choose |
|
|
1301 | a suitable value. The memory pointed to by \f(CW\*(C`path\*(C'\fR must point to the same |
|
|
1302 | path for as long as the watcher is active. |
|
|
1303 | .Sp |
|
|
1304 | The callback will be receive \f(CW\*(C`EV_STAT\*(C'\fR when a change was detected, |
|
|
1305 | relative to the attributes at the time the watcher was started (or the |
|
|
1306 | last change was detected). |
|
|
1307 | .IP "ev_stat_stat (ev_stat *)" 4 |
|
|
1308 | .IX Item "ev_stat_stat (ev_stat *)" |
|
|
1309 | Updates the stat buffer immediately with new values. If you change the |
|
|
1310 | watched path in your callback, you could call this fucntion to avoid |
|
|
1311 | detecting this change (while introducing a race condition). Can also be |
|
|
1312 | useful simply to find out the new values. |
|
|
1313 | .IP "ev_statdata attr [read\-only]" 4 |
|
|
1314 | .IX Item "ev_statdata attr [read-only]" |
|
|
1315 | The most-recently detected attributes of the file. Although the type is of |
|
|
1316 | \&\f(CW\*(C`ev_statdata\*(C'\fR, this is usually the (or one of the) \f(CW\*(C`struct stat\*(C'\fR types |
|
|
1317 | suitable for your system. If the \f(CW\*(C`st_nlink\*(C'\fR member is \f(CW0\fR, then there |
|
|
1318 | was some error while \f(CW\*(C`stat\*(C'\fRing the file. |
|
|
1319 | .IP "ev_statdata prev [read\-only]" 4 |
|
|
1320 | .IX Item "ev_statdata prev [read-only]" |
|
|
1321 | The previous attributes of the file. The callback gets invoked whenever |
|
|
1322 | \&\f(CW\*(C`prev\*(C'\fR != \f(CW\*(C`attr\*(C'\fR. |
|
|
1323 | .IP "ev_tstamp interval [read\-only]" 4 |
|
|
1324 | .IX Item "ev_tstamp interval [read-only]" |
|
|
1325 | The specified interval. |
|
|
1326 | .IP "const char *path [read\-only]" 4 |
|
|
1327 | .IX Item "const char *path [read-only]" |
|
|
1328 | The filesystem path that is being watched. |
|
|
1329 | .PP |
|
|
1330 | Example: Watch \f(CW\*(C`/etc/passwd\*(C'\fR for attribute changes. |
|
|
1331 | .PP |
|
|
1332 | .Vb 15 |
|
|
1333 | \& static void |
|
|
1334 | \& passwd_cb (struct ev_loop *loop, ev_stat *w, int revents) |
|
|
1335 | \& { |
|
|
1336 | \& /* /etc/passwd changed in some way */ |
|
|
1337 | \& if (w->attr.st_nlink) |
|
|
1338 | \& { |
|
|
1339 | \& printf ("passwd current size %ld\en", (long)w->attr.st_size); |
|
|
1340 | \& printf ("passwd current atime %ld\en", (long)w->attr.st_mtime); |
|
|
1341 | \& printf ("passwd current mtime %ld\en", (long)w->attr.st_mtime); |
|
|
1342 | \& } |
|
|
1343 | \& else |
|
|
1344 | \& /* you shalt not abuse printf for puts */ |
|
|
1345 | \& puts ("wow, /etc/passwd is not there, expect problems. " |
|
|
1346 | \& "if this is windows, they already arrived\en"); |
|
|
1347 | \& } |
|
|
1348 | .Ve |
|
|
1349 | .PP |
|
|
1350 | .Vb 2 |
|
|
1351 | \& ... |
|
|
1352 | \& ev_stat passwd; |
|
|
1353 | .Ve |
|
|
1354 | .PP |
|
|
1355 | .Vb 2 |
|
|
1356 | \& ev_stat_init (&passwd, passwd_cb, "/etc/passwd"); |
|
|
1357 | \& ev_stat_start (loop, &passwd); |
|
|
1358 | .Ve |
827 | .ie n .Sh """ev_idle"" \- when you've got nothing better to do" |
1359 | .ie n .Sh """ev_idle"" \- when you've got nothing better to do..." |
828 | .el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do" |
1360 | .el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do..." |
829 | .IX Subsection "ev_idle - when you've got nothing better to do" |
1361 | .IX Subsection "ev_idle - when you've got nothing better to do..." |
830 | Idle watchers trigger events when there are no other events are pending |
1362 | Idle watchers trigger events when there are no other events are pending |
831 | (prepare, check and other idle watchers do not count). That is, as long |
1363 | (prepare, check and other idle watchers do not count). That is, as long |
832 | as your process is busy handling sockets or timeouts (or even signals, |
1364 | as your process is busy handling sockets or timeouts (or even signals, |
833 | imagine) it will not be triggered. But when your process is idle all idle |
1365 | imagine) it will not be triggered. But when your process is idle all idle |
834 | watchers are being called again and again, once per event loop iteration \- |
1366 | watchers are being called again and again, once per event loop iteration \- |
… | |
… | |
845 | .IP "ev_idle_init (ev_signal *, callback)" 4 |
1377 | .IP "ev_idle_init (ev_signal *, callback)" 4 |
846 | .IX Item "ev_idle_init (ev_signal *, callback)" |
1378 | .IX Item "ev_idle_init (ev_signal *, callback)" |
847 | Initialises and configures the idle watcher \- it has no parameters of any |
1379 | Initialises and configures the idle watcher \- it has no parameters of any |
848 | kind. There is a \f(CW\*(C`ev_idle_set\*(C'\fR macro, but using it is utterly pointless, |
1380 | kind. There is a \f(CW\*(C`ev_idle_set\*(C'\fR macro, but using it is utterly pointless, |
849 | believe me. |
1381 | believe me. |
|
|
1382 | .PP |
|
|
1383 | Example: dynamically allocate an \f(CW\*(C`ev_idle\*(C'\fR, start it, and in the |
|
|
1384 | callback, free it. Alos, use no error checking, as usual. |
|
|
1385 | .PP |
|
|
1386 | .Vb 7 |
|
|
1387 | \& static void |
|
|
1388 | \& idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
|
|
1389 | \& { |
|
|
1390 | \& free (w); |
|
|
1391 | \& // now do something you wanted to do when the program has |
|
|
1392 | \& // no longer asnything immediate to do. |
|
|
1393 | \& } |
|
|
1394 | .Ve |
|
|
1395 | .PP |
|
|
1396 | .Vb 3 |
|
|
1397 | \& struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle)); |
|
|
1398 | \& ev_idle_init (idle_watcher, idle_cb); |
|
|
1399 | \& ev_idle_start (loop, idle_cb); |
|
|
1400 | .Ve |
850 | .ie n .Sh """ev_prepare""\fP and \f(CW""ev_check"" \- customise your event loop" |
1401 | .ie n .Sh """ev_prepare""\fP and \f(CW""ev_check"" \- customise your event loop!" |
851 | .el .Sh "\f(CWev_prepare\fP and \f(CWev_check\fP \- customise your event loop" |
1402 | .el .Sh "\f(CWev_prepare\fP and \f(CWev_check\fP \- customise your event loop!" |
852 | .IX Subsection "ev_prepare and ev_check - customise your event loop" |
1403 | .IX Subsection "ev_prepare and ev_check - customise your event loop!" |
853 | Prepare and check watchers are usually (but not always) used in tandem: |
1404 | Prepare and check watchers are usually (but not always) used in tandem: |
854 | prepare watchers get invoked before the process blocks and check watchers |
1405 | prepare watchers get invoked before the process blocks and check watchers |
855 | afterwards. |
1406 | afterwards. |
856 | .PP |
1407 | .PP |
|
|
1408 | You \fImust not\fR call \f(CW\*(C`ev_loop\*(C'\fR or similar functions that enter |
|
|
1409 | the current event loop from either \f(CW\*(C`ev_prepare\*(C'\fR or \f(CW\*(C`ev_check\*(C'\fR |
|
|
1410 | watchers. Other loops than the current one are fine, however. The |
|
|
1411 | rationale behind this is that you do not need to check for recursion in |
|
|
1412 | those watchers, i.e. the sequence will always be \f(CW\*(C`ev_prepare\*(C'\fR, blocking, |
|
|
1413 | \&\f(CW\*(C`ev_check\*(C'\fR so if you have one watcher of each kind they will always be |
|
|
1414 | called in pairs bracketing the blocking call. |
|
|
1415 | .PP |
857 | Their main purpose is to integrate other event mechanisms into libev. This |
1416 | Their main purpose is to integrate other event mechanisms into libev and |
858 | could be used, for example, to track variable changes, implement your own |
1417 | their use is somewhat advanced. This could be used, for example, to track |
859 | watchers, integrate net-snmp or a coroutine library and lots more. |
1418 | variable changes, implement your own watchers, integrate net-snmp or a |
|
|
1419 | coroutine library and lots more. They are also occasionally useful if |
|
|
1420 | you cache some data and want to flush it before blocking (for example, |
|
|
1421 | in X programs you might want to do an \f(CW\*(C`XFlush ()\*(C'\fR in an \f(CW\*(C`ev_prepare\*(C'\fR |
|
|
1422 | watcher). |
860 | .PP |
1423 | .PP |
861 | This is done by examining in each prepare call which file descriptors need |
1424 | This is done by examining in each prepare call which file descriptors need |
862 | to be watched by the other library, registering \f(CW\*(C`ev_io\*(C'\fR watchers for |
1425 | to be watched by the other library, registering \f(CW\*(C`ev_io\*(C'\fR watchers for |
863 | them and starting an \f(CW\*(C`ev_timer\*(C'\fR watcher for any timeouts (many libraries |
1426 | them and starting an \f(CW\*(C`ev_timer\*(C'\fR watcher for any timeouts (many libraries |
864 | provide just this functionality). Then, in the check watcher you check for |
1427 | provide just this functionality). Then, in the check watcher you check for |
… | |
… | |
882 | .IX Item "ev_check_init (ev_check *, callback)" |
1445 | .IX Item "ev_check_init (ev_check *, callback)" |
883 | .PD |
1446 | .PD |
884 | Initialises and configures the prepare or check watcher \- they have no |
1447 | Initialises and configures the prepare or check watcher \- they have no |
885 | parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR |
1448 | parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR |
886 | macros, but using them is utterly, utterly and completely pointless. |
1449 | macros, but using them is utterly, utterly and completely pointless. |
|
|
1450 | .PP |
|
|
1451 | Example: To include a library such as adns, you would add \s-1IO\s0 watchers |
|
|
1452 | and a timeout watcher in a prepare handler, as required by libadns, and |
|
|
1453 | in a check watcher, destroy them and call into libadns. What follows is |
|
|
1454 | pseudo-code only of course: |
|
|
1455 | .PP |
|
|
1456 | .Vb 2 |
|
|
1457 | \& static ev_io iow [nfd]; |
|
|
1458 | \& static ev_timer tw; |
|
|
1459 | .Ve |
|
|
1460 | .PP |
|
|
1461 | .Vb 9 |
|
|
1462 | \& static void |
|
|
1463 | \& io_cb (ev_loop *loop, ev_io *w, int revents) |
|
|
1464 | \& { |
|
|
1465 | \& // set the relevant poll flags |
|
|
1466 | \& // could also call adns_processreadable etc. here |
|
|
1467 | \& struct pollfd *fd = (struct pollfd *)w->data; |
|
|
1468 | \& if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
|
|
1469 | \& if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
|
|
1470 | \& } |
|
|
1471 | .Ve |
|
|
1472 | .PP |
|
|
1473 | .Vb 7 |
|
|
1474 | \& // create io watchers for each fd and a timer before blocking |
|
|
1475 | \& static void |
|
|
1476 | \& adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
|
|
1477 | \& { |
|
|
1478 | \& int timeout = 3600000;truct pollfd fds [nfd]; |
|
|
1479 | \& // actual code will need to loop here and realloc etc. |
|
|
1480 | \& adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
|
|
1481 | .Ve |
|
|
1482 | .PP |
|
|
1483 | .Vb 3 |
|
|
1484 | \& /* the callback is illegal, but won't be called as we stop during check */ |
|
|
1485 | \& ev_timer_init (&tw, 0, timeout * 1e-3); |
|
|
1486 | \& ev_timer_start (loop, &tw); |
|
|
1487 | .Ve |
|
|
1488 | .PP |
|
|
1489 | .Vb 6 |
|
|
1490 | \& // create on ev_io per pollfd |
|
|
1491 | \& for (int i = 0; i < nfd; ++i) |
|
|
1492 | \& { |
|
|
1493 | \& ev_io_init (iow + i, io_cb, fds [i].fd, |
|
|
1494 | \& ((fds [i].events & POLLIN ? EV_READ : 0) |
|
|
1495 | \& | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
|
|
1496 | .Ve |
|
|
1497 | .PP |
|
|
1498 | .Vb 5 |
|
|
1499 | \& fds [i].revents = 0; |
|
|
1500 | \& iow [i].data = fds + i; |
|
|
1501 | \& ev_io_start (loop, iow + i); |
|
|
1502 | \& } |
|
|
1503 | \& } |
|
|
1504 | .Ve |
|
|
1505 | .PP |
|
|
1506 | .Vb 5 |
|
|
1507 | \& // stop all watchers after blocking |
|
|
1508 | \& static void |
|
|
1509 | \& adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
|
|
1510 | \& { |
|
|
1511 | \& ev_timer_stop (loop, &tw); |
|
|
1512 | .Ve |
|
|
1513 | .PP |
|
|
1514 | .Vb 2 |
|
|
1515 | \& for (int i = 0; i < nfd; ++i) |
|
|
1516 | \& ev_io_stop (loop, iow + i); |
|
|
1517 | .Ve |
|
|
1518 | .PP |
|
|
1519 | .Vb 2 |
|
|
1520 | \& adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
|
|
1521 | \& } |
|
|
1522 | .Ve |
|
|
1523 | .ie n .Sh """ev_embed"" \- when one backend isn't enough..." |
|
|
1524 | .el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..." |
|
|
1525 | .IX Subsection "ev_embed - when one backend isn't enough..." |
|
|
1526 | This is a rather advanced watcher type that lets you embed one event loop |
|
|
1527 | into another (currently only \f(CW\*(C`ev_io\*(C'\fR events are supported in the embedded |
|
|
1528 | loop, other types of watchers might be handled in a delayed or incorrect |
|
|
1529 | fashion and must not be used). |
|
|
1530 | .PP |
|
|
1531 | There are primarily two reasons you would want that: work around bugs and |
|
|
1532 | prioritise I/O. |
|
|
1533 | .PP |
|
|
1534 | As an example for a bug workaround, the kqueue backend might only support |
|
|
1535 | sockets on some platform, so it is unusable as generic backend, but you |
|
|
1536 | still want to make use of it because you have many sockets and it scales |
|
|
1537 | so nicely. In this case, you would create a kqueue-based loop and embed it |
|
|
1538 | into your default loop (which might use e.g. poll). Overall operation will |
|
|
1539 | be a bit slower because first libev has to poll and then call kevent, but |
|
|
1540 | at least you can use both at what they are best. |
|
|
1541 | .PP |
|
|
1542 | As for prioritising I/O: rarely you have the case where some fds have |
|
|
1543 | to be watched and handled very quickly (with low latency), and even |
|
|
1544 | priorities and idle watchers might have too much overhead. In this case |
|
|
1545 | you would put all the high priority stuff in one loop and all the rest in |
|
|
1546 | a second one, and embed the second one in the first. |
|
|
1547 | .PP |
|
|
1548 | As long as the watcher is active, the callback will be invoked every time |
|
|
1549 | there might be events pending in the embedded loop. The callback must then |
|
|
1550 | call \f(CW\*(C`ev_embed_sweep (mainloop, watcher)\*(C'\fR to make a single sweep and invoke |
|
|
1551 | their callbacks (you could also start an idle watcher to give the embedded |
|
|
1552 | loop strictly lower priority for example). You can also set the callback |
|
|
1553 | to \f(CW0\fR, in which case the embed watcher will automatically execute the |
|
|
1554 | embedded loop sweep. |
|
|
1555 | .PP |
|
|
1556 | As long as the watcher is started it will automatically handle events. The |
|
|
1557 | callback will be invoked whenever some events have been handled. You can |
|
|
1558 | set the callback to \f(CW0\fR to avoid having to specify one if you are not |
|
|
1559 | interested in that. |
|
|
1560 | .PP |
|
|
1561 | Also, there have not currently been made special provisions for forking: |
|
|
1562 | when you fork, you not only have to call \f(CW\*(C`ev_loop_fork\*(C'\fR on both loops, |
|
|
1563 | but you will also have to stop and restart any \f(CW\*(C`ev_embed\*(C'\fR watchers |
|
|
1564 | yourself. |
|
|
1565 | .PP |
|
|
1566 | Unfortunately, not all backends are embeddable, only the ones returned by |
|
|
1567 | \&\f(CW\*(C`ev_embeddable_backends\*(C'\fR are, which, unfortunately, does not include any |
|
|
1568 | portable one. |
|
|
1569 | .PP |
|
|
1570 | So when you want to use this feature you will always have to be prepared |
|
|
1571 | that you cannot get an embeddable loop. The recommended way to get around |
|
|
1572 | this is to have a separate variables for your embeddable loop, try to |
|
|
1573 | create it, and if that fails, use the normal loop for everything: |
|
|
1574 | .PP |
|
|
1575 | .Vb 3 |
|
|
1576 | \& struct ev_loop *loop_hi = ev_default_init (0); |
|
|
1577 | \& struct ev_loop *loop_lo = 0; |
|
|
1578 | \& struct ev_embed embed; |
|
|
1579 | .Ve |
|
|
1580 | .PP |
|
|
1581 | .Vb 5 |
|
|
1582 | \& // see if there is a chance of getting one that works |
|
|
1583 | \& // (remember that a flags value of 0 means autodetection) |
|
|
1584 | \& loop_lo = ev_embeddable_backends () & ev_recommended_backends () |
|
|
1585 | \& ? ev_loop_new (ev_embeddable_backends () & ev_recommended_backends ()) |
|
|
1586 | \& : 0; |
|
|
1587 | .Ve |
|
|
1588 | .PP |
|
|
1589 | .Vb 8 |
|
|
1590 | \& // if we got one, then embed it, otherwise default to loop_hi |
|
|
1591 | \& if (loop_lo) |
|
|
1592 | \& { |
|
|
1593 | \& ev_embed_init (&embed, 0, loop_lo); |
|
|
1594 | \& ev_embed_start (loop_hi, &embed); |
|
|
1595 | \& } |
|
|
1596 | \& else |
|
|
1597 | \& loop_lo = loop_hi; |
|
|
1598 | .Ve |
|
|
1599 | .IP "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
|
|
1600 | .IX Item "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" |
|
|
1601 | .PD 0 |
|
|
1602 | .IP "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
|
|
1603 | .IX Item "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" |
|
|
1604 | .PD |
|
|
1605 | Configures the watcher to embed the given loop, which must be |
|
|
1606 | embeddable. If the callback is \f(CW0\fR, then \f(CW\*(C`ev_embed_sweep\*(C'\fR will be |
|
|
1607 | invoked automatically, otherwise it is the responsibility of the callback |
|
|
1608 | to invoke it (it will continue to be called until the sweep has been done, |
|
|
1609 | if you do not want thta, you need to temporarily stop the embed watcher). |
|
|
1610 | .IP "ev_embed_sweep (loop, ev_embed *)" 4 |
|
|
1611 | .IX Item "ev_embed_sweep (loop, ev_embed *)" |
|
|
1612 | Make a single, non-blocking sweep over the embedded loop. This works |
|
|
1613 | similarly to \f(CW\*(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\*(C'\fR, but in the most |
|
|
1614 | apropriate way for embedded loops. |
|
|
1615 | .IP "struct ev_loop *loop [read\-only]" 4 |
|
|
1616 | .IX Item "struct ev_loop *loop [read-only]" |
|
|
1617 | The embedded event loop. |
887 | .SH "OTHER FUNCTIONS" |
1618 | .SH "OTHER FUNCTIONS" |
888 | .IX Header "OTHER FUNCTIONS" |
1619 | .IX Header "OTHER FUNCTIONS" |
889 | There are some other functions of possible interest. Described. Here. Now. |
1620 | There are some other functions of possible interest. Described. Here. Now. |
890 | .IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4 |
1621 | .IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4 |
891 | .IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" |
1622 | .IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" |
… | |
… | |
920 | .Ve |
1651 | .Ve |
921 | .Sp |
1652 | .Sp |
922 | .Vb 1 |
1653 | .Vb 1 |
923 | \& ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0); |
1654 | \& ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0); |
924 | .Ve |
1655 | .Ve |
925 | .IP "ev_feed_event (loop, watcher, int events)" 4 |
1656 | .IP "ev_feed_event (ev_loop *, watcher *, int revents)" 4 |
926 | .IX Item "ev_feed_event (loop, watcher, int events)" |
1657 | .IX Item "ev_feed_event (ev_loop *, watcher *, int revents)" |
927 | Feeds the given event set into the event loop, as if the specified event |
1658 | Feeds the given event set into the event loop, as if the specified event |
928 | had happened for the specified watcher (which must be a pointer to an |
1659 | had happened for the specified watcher (which must be a pointer to an |
929 | initialised but not necessarily started event watcher). |
1660 | initialised but not necessarily started event watcher). |
930 | .IP "ev_feed_fd_event (loop, int fd, int revents)" 4 |
1661 | .IP "ev_feed_fd_event (ev_loop *, int fd, int revents)" 4 |
931 | .IX Item "ev_feed_fd_event (loop, int fd, int revents)" |
1662 | .IX Item "ev_feed_fd_event (ev_loop *, int fd, int revents)" |
932 | Feed an event on the given fd, as if a file descriptor backend detected |
1663 | Feed an event on the given fd, as if a file descriptor backend detected |
933 | the given events it. |
1664 | the given events it. |
934 | .IP "ev_feed_signal_event (loop, int signum)" 4 |
1665 | .IP "ev_feed_signal_event (ev_loop *loop, int signum)" 4 |
935 | .IX Item "ev_feed_signal_event (loop, int signum)" |
1666 | .IX Item "ev_feed_signal_event (ev_loop *loop, int signum)" |
936 | Feed an event as if the given signal occured (loop must be the default loop!). |
1667 | Feed an event as if the given signal occured (\f(CW\*(C`loop\*(C'\fR must be the default |
|
|
1668 | loop!). |
937 | .SH "LIBEVENT EMULATION" |
1669 | .SH "LIBEVENT EMULATION" |
938 | .IX Header "LIBEVENT EMULATION" |
1670 | .IX Header "LIBEVENT EMULATION" |
939 | Libev offers a compatibility emulation layer for libevent. It cannot |
1671 | Libev offers a compatibility emulation layer for libevent. It cannot |
940 | emulate the internals of libevent, so here are some usage hints: |
1672 | emulate the internals of libevent, so here are some usage hints: |
941 | .IP "* Use it by including <event.h>, as usual." 4 |
1673 | .IP "* Use it by including <event.h>, as usual." 4 |
… | |
… | |
952 | .IP "* The libev emulation is \fInot\fR \s-1ABI\s0 compatible to libevent, you need to use the libev header file and library." 4 |
1684 | .IP "* The libev emulation is \fInot\fR \s-1ABI\s0 compatible to libevent, you need to use the libev header file and library." 4 |
953 | .IX Item "The libev emulation is not ABI compatible to libevent, you need to use the libev header file and library." |
1685 | .IX Item "The libev emulation is not ABI compatible to libevent, you need to use the libev header file and library." |
954 | .PD |
1686 | .PD |
955 | .SH "\*(C+ SUPPORT" |
1687 | .SH "\*(C+ SUPPORT" |
956 | .IX Header " SUPPORT" |
1688 | .IX Header " SUPPORT" |
957 | \&\s-1TBD\s0. |
1689 | Libev comes with some simplistic wrapper classes for \*(C+ that mainly allow |
|
|
1690 | you to use some convinience methods to start/stop watchers and also change |
|
|
1691 | the callback model to a model using method callbacks on objects. |
|
|
1692 | .PP |
|
|
1693 | To use it, |
|
|
1694 | .PP |
|
|
1695 | .Vb 1 |
|
|
1696 | \& #include <ev++.h> |
|
|
1697 | .Ve |
|
|
1698 | .PP |
|
|
1699 | (it is not installed by default). This automatically includes \fIev.h\fR |
|
|
1700 | and puts all of its definitions (many of them macros) into the global |
|
|
1701 | namespace. All \*(C+ specific things are put into the \f(CW\*(C`ev\*(C'\fR namespace. |
|
|
1702 | .PP |
|
|
1703 | It should support all the same embedding options as \fIev.h\fR, most notably |
|
|
1704 | \&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. |
|
|
1705 | .PP |
|
|
1706 | Here is a list of things available in the \f(CW\*(C`ev\*(C'\fR namespace: |
|
|
1707 | .ie n .IP """ev::READ""\fR, \f(CW""ev::WRITE"" etc." 4 |
|
|
1708 | .el .IP "\f(CWev::READ\fR, \f(CWev::WRITE\fR etc." 4 |
|
|
1709 | .IX Item "ev::READ, ev::WRITE etc." |
|
|
1710 | These are just enum values with the same values as the \f(CW\*(C`EV_READ\*(C'\fR etc. |
|
|
1711 | macros from \fIev.h\fR. |
|
|
1712 | .ie n .IP """ev::tstamp""\fR, \f(CW""ev::now""" 4 |
|
|
1713 | .el .IP "\f(CWev::tstamp\fR, \f(CWev::now\fR" 4 |
|
|
1714 | .IX Item "ev::tstamp, ev::now" |
|
|
1715 | Aliases to the same types/functions as with the \f(CW\*(C`ev_\*(C'\fR prefix. |
|
|
1716 | .ie n .IP """ev::io""\fR, \f(CW""ev::timer""\fR, \f(CW""ev::periodic""\fR, \f(CW""ev::idle""\fR, \f(CW""ev::sig"" etc." 4 |
|
|
1717 | .el .IP "\f(CWev::io\fR, \f(CWev::timer\fR, \f(CWev::periodic\fR, \f(CWev::idle\fR, \f(CWev::sig\fR etc." 4 |
|
|
1718 | .IX Item "ev::io, ev::timer, ev::periodic, ev::idle, ev::sig etc." |
|
|
1719 | For each \f(CW\*(C`ev_TYPE\*(C'\fR watcher in \fIev.h\fR there is a corresponding class of |
|
|
1720 | the same name in the \f(CW\*(C`ev\*(C'\fR namespace, with the exception of \f(CW\*(C`ev_signal\*(C'\fR |
|
|
1721 | which is called \f(CW\*(C`ev::sig\*(C'\fR to avoid clashes with the \f(CW\*(C`signal\*(C'\fR macro |
|
|
1722 | defines by many implementations. |
|
|
1723 | .Sp |
|
|
1724 | All of those classes have these methods: |
|
|
1725 | .RS 4 |
|
|
1726 | .IP "ev::TYPE::TYPE (object *, object::method *)" 4 |
|
|
1727 | .IX Item "ev::TYPE::TYPE (object *, object::method *)" |
|
|
1728 | .PD 0 |
|
|
1729 | .IP "ev::TYPE::TYPE (object *, object::method *, struct ev_loop *)" 4 |
|
|
1730 | .IX Item "ev::TYPE::TYPE (object *, object::method *, struct ev_loop *)" |
|
|
1731 | .IP "ev::TYPE::~TYPE" 4 |
|
|
1732 | .IX Item "ev::TYPE::~TYPE" |
|
|
1733 | .PD |
|
|
1734 | The constructor takes a pointer to an object and a method pointer to |
|
|
1735 | the event handler callback to call in this class. The constructor calls |
|
|
1736 | \&\f(CW\*(C`ev_init\*(C'\fR for you, which means you have to call the \f(CW\*(C`set\*(C'\fR method |
|
|
1737 | before starting it. If you do not specify a loop then the constructor |
|
|
1738 | automatically associates the default loop with this watcher. |
|
|
1739 | .Sp |
|
|
1740 | The destructor automatically stops the watcher if it is active. |
|
|
1741 | .IP "w\->set (struct ev_loop *)" 4 |
|
|
1742 | .IX Item "w->set (struct ev_loop *)" |
|
|
1743 | Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only |
|
|
1744 | do this when the watcher is inactive (and not pending either). |
|
|
1745 | .IP "w\->set ([args])" 4 |
|
|
1746 | .IX Item "w->set ([args])" |
|
|
1747 | Basically the same as \f(CW\*(C`ev_TYPE_set\*(C'\fR, with the same args. Must be |
|
|
1748 | called at least once. Unlike the C counterpart, an active watcher gets |
|
|
1749 | automatically stopped and restarted. |
|
|
1750 | .IP "w\->start ()" 4 |
|
|
1751 | .IX Item "w->start ()" |
|
|
1752 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument as the |
|
|
1753 | constructor already takes the loop. |
|
|
1754 | .IP "w\->stop ()" 4 |
|
|
1755 | .IX Item "w->stop ()" |
|
|
1756 | Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument. |
|
|
1757 | .ie n .IP "w\->again () ""ev::timer""\fR, \f(CW""ev::periodic"" only" 4 |
|
|
1758 | .el .IP "w\->again () \f(CWev::timer\fR, \f(CWev::periodic\fR only" 4 |
|
|
1759 | .IX Item "w->again () ev::timer, ev::periodic only" |
|
|
1760 | For \f(CW\*(C`ev::timer\*(C'\fR and \f(CW\*(C`ev::periodic\*(C'\fR, this invokes the corresponding |
|
|
1761 | \&\f(CW\*(C`ev_TYPE_again\*(C'\fR function. |
|
|
1762 | .ie n .IP "w\->sweep () ""ev::embed"" only" 4 |
|
|
1763 | .el .IP "w\->sweep () \f(CWev::embed\fR only" 4 |
|
|
1764 | .IX Item "w->sweep () ev::embed only" |
|
|
1765 | Invokes \f(CW\*(C`ev_embed_sweep\*(C'\fR. |
|
|
1766 | .RE |
|
|
1767 | .RS 4 |
|
|
1768 | .RE |
|
|
1769 | .PP |
|
|
1770 | Example: Define a class with an \s-1IO\s0 and idle watcher, start one of them in |
|
|
1771 | the constructor. |
|
|
1772 | .PP |
|
|
1773 | .Vb 4 |
|
|
1774 | \& class myclass |
|
|
1775 | \& { |
|
|
1776 | \& ev_io io; void io_cb (ev::io &w, int revents); |
|
|
1777 | \& ev_idle idle void idle_cb (ev::idle &w, int revents); |
|
|
1778 | .Ve |
|
|
1779 | .PP |
|
|
1780 | .Vb 2 |
|
|
1781 | \& myclass (); |
|
|
1782 | \& } |
|
|
1783 | .Ve |
|
|
1784 | .PP |
|
|
1785 | .Vb 6 |
|
|
1786 | \& myclass::myclass (int fd) |
|
|
1787 | \& : io (this, &myclass::io_cb), |
|
|
1788 | \& idle (this, &myclass::idle_cb) |
|
|
1789 | \& { |
|
|
1790 | \& io.start (fd, ev::READ); |
|
|
1791 | \& } |
|
|
1792 | .Ve |
|
|
1793 | .SH "EMBEDDING" |
|
|
1794 | .IX Header "EMBEDDING" |
|
|
1795 | Libev can (and often is) directly embedded into host |
|
|
1796 | applications. Examples of applications that embed it include the Deliantra |
|
|
1797 | Game Server, the \s-1EV\s0 perl module, the \s-1GNU\s0 Virtual Private Ethernet (gvpe) |
|
|
1798 | and rxvt\-unicode. |
|
|
1799 | .PP |
|
|
1800 | The goal is to enable you to just copy the neecssary files into your |
|
|
1801 | source directory without having to change even a single line in them, so |
|
|
1802 | you can easily upgrade by simply copying (or having a checked-out copy of |
|
|
1803 | libev somewhere in your source tree). |
|
|
1804 | .Sh "\s-1FILESETS\s0" |
|
|
1805 | .IX Subsection "FILESETS" |
|
|
1806 | Depending on what features you need you need to include one or more sets of files |
|
|
1807 | in your app. |
|
|
1808 | .PP |
|
|
1809 | \fI\s-1CORE\s0 \s-1EVENT\s0 \s-1LOOP\s0\fR |
|
|
1810 | .IX Subsection "CORE EVENT LOOP" |
|
|
1811 | .PP |
|
|
1812 | To include only the libev core (all the \f(CW\*(C`ev_*\*(C'\fR functions), with manual |
|
|
1813 | configuration (no autoconf): |
|
|
1814 | .PP |
|
|
1815 | .Vb 2 |
|
|
1816 | \& #define EV_STANDALONE 1 |
|
|
1817 | \& #include "ev.c" |
|
|
1818 | .Ve |
|
|
1819 | .PP |
|
|
1820 | This will automatically include \fIev.h\fR, too, and should be done in a |
|
|
1821 | single C source file only to provide the function implementations. To use |
|
|
1822 | it, do the same for \fIev.h\fR in all files wishing to use this \s-1API\s0 (best |
|
|
1823 | done by writing a wrapper around \fIev.h\fR that you can include instead and |
|
|
1824 | where you can put other configuration options): |
|
|
1825 | .PP |
|
|
1826 | .Vb 2 |
|
|
1827 | \& #define EV_STANDALONE 1 |
|
|
1828 | \& #include "ev.h" |
|
|
1829 | .Ve |
|
|
1830 | .PP |
|
|
1831 | Both header files and implementation files can be compiled with a \*(C+ |
|
|
1832 | compiler (at least, thats a stated goal, and breakage will be treated |
|
|
1833 | as a bug). |
|
|
1834 | .PP |
|
|
1835 | You need the following files in your source tree, or in a directory |
|
|
1836 | in your include path (e.g. in libev/ when using \-Ilibev): |
|
|
1837 | .PP |
|
|
1838 | .Vb 4 |
|
|
1839 | \& ev.h |
|
|
1840 | \& ev.c |
|
|
1841 | \& ev_vars.h |
|
|
1842 | \& ev_wrap.h |
|
|
1843 | .Ve |
|
|
1844 | .PP |
|
|
1845 | .Vb 1 |
|
|
1846 | \& ev_win32.c required on win32 platforms only |
|
|
1847 | .Ve |
|
|
1848 | .PP |
|
|
1849 | .Vb 5 |
|
|
1850 | \& ev_select.c only when select backend is enabled (which is by default) |
|
|
1851 | \& ev_poll.c only when poll backend is enabled (disabled by default) |
|
|
1852 | \& ev_epoll.c only when the epoll backend is enabled (disabled by default) |
|
|
1853 | \& ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
|
|
1854 | \& ev_port.c only when the solaris port backend is enabled (disabled by default) |
|
|
1855 | .Ve |
|
|
1856 | .PP |
|
|
1857 | \&\fIev.c\fR includes the backend files directly when enabled, so you only need |
|
|
1858 | to compile this single file. |
|
|
1859 | .PP |
|
|
1860 | \fI\s-1LIBEVENT\s0 \s-1COMPATIBILITY\s0 \s-1API\s0\fR |
|
|
1861 | .IX Subsection "LIBEVENT COMPATIBILITY API" |
|
|
1862 | .PP |
|
|
1863 | To include the libevent compatibility \s-1API\s0, also include: |
|
|
1864 | .PP |
|
|
1865 | .Vb 1 |
|
|
1866 | \& #include "event.c" |
|
|
1867 | .Ve |
|
|
1868 | .PP |
|
|
1869 | in the file including \fIev.c\fR, and: |
|
|
1870 | .PP |
|
|
1871 | .Vb 1 |
|
|
1872 | \& #include "event.h" |
|
|
1873 | .Ve |
|
|
1874 | .PP |
|
|
1875 | in the files that want to use the libevent \s-1API\s0. This also includes \fIev.h\fR. |
|
|
1876 | .PP |
|
|
1877 | You need the following additional files for this: |
|
|
1878 | .PP |
|
|
1879 | .Vb 2 |
|
|
1880 | \& event.h |
|
|
1881 | \& event.c |
|
|
1882 | .Ve |
|
|
1883 | .PP |
|
|
1884 | \fI\s-1AUTOCONF\s0 \s-1SUPPORT\s0\fR |
|
|
1885 | .IX Subsection "AUTOCONF SUPPORT" |
|
|
1886 | .PP |
|
|
1887 | Instead of using \f(CW\*(C`EV_STANDALONE=1\*(C'\fR and providing your config in |
|
|
1888 | whatever way you want, you can also \f(CW\*(C`m4_include([libev.m4])\*(C'\fR in your |
|
|
1889 | \&\fIconfigure.ac\fR and leave \f(CW\*(C`EV_STANDALONE\*(C'\fR undefined. \fIev.c\fR will then |
|
|
1890 | include \fIconfig.h\fR and configure itself accordingly. |
|
|
1891 | .PP |
|
|
1892 | For this of course you need the m4 file: |
|
|
1893 | .PP |
|
|
1894 | .Vb 1 |
|
|
1895 | \& libev.m4 |
|
|
1896 | .Ve |
|
|
1897 | .Sh "\s-1PREPROCESSOR\s0 \s-1SYMBOLS/MACROS\s0" |
|
|
1898 | .IX Subsection "PREPROCESSOR SYMBOLS/MACROS" |
|
|
1899 | Libev can be configured via a variety of preprocessor symbols you have to define |
|
|
1900 | before including any of its files. The default is not to build for multiplicity |
|
|
1901 | and only include the select backend. |
|
|
1902 | .IP "\s-1EV_STANDALONE\s0" 4 |
|
|
1903 | .IX Item "EV_STANDALONE" |
|
|
1904 | Must always be \f(CW1\fR if you do not use autoconf configuration, which |
|
|
1905 | keeps libev from including \fIconfig.h\fR, and it also defines dummy |
|
|
1906 | implementations for some libevent functions (such as logging, which is not |
|
|
1907 | supported). It will also not define any of the structs usually found in |
|
|
1908 | \&\fIevent.h\fR that are not directly supported by the libev core alone. |
|
|
1909 | .IP "\s-1EV_USE_MONOTONIC\s0" 4 |
|
|
1910 | .IX Item "EV_USE_MONOTONIC" |
|
|
1911 | If defined to be \f(CW1\fR, libev will try to detect the availability of the |
|
|
1912 | monotonic clock option at both compiletime and runtime. Otherwise no use |
|
|
1913 | of the monotonic clock option will be attempted. If you enable this, you |
|
|
1914 | usually have to link against librt or something similar. Enabling it when |
|
|
1915 | the functionality isn't available is safe, though, althoguh you have |
|
|
1916 | to make sure you link against any libraries where the \f(CW\*(C`clock_gettime\*(C'\fR |
|
|
1917 | function is hiding in (often \fI\-lrt\fR). |
|
|
1918 | .IP "\s-1EV_USE_REALTIME\s0" 4 |
|
|
1919 | .IX Item "EV_USE_REALTIME" |
|
|
1920 | If defined to be \f(CW1\fR, libev will try to detect the availability of the |
|
|
1921 | realtime clock option at compiletime (and assume its availability at |
|
|
1922 | runtime if successful). Otherwise no use of the realtime clock option will |
|
|
1923 | be attempted. This effectively replaces \f(CW\*(C`gettimeofday\*(C'\fR by \f(CW\*(C`clock_get |
|
|
1924 | (CLOCK_REALTIME, ...)\*(C'\fR and will not normally affect correctness. See tzhe note about libraries |
|
|
1925 | in the description of \f(CW\*(C`EV_USE_MONOTONIC\*(C'\fR, though. |
|
|
1926 | .IP "\s-1EV_USE_SELECT\s0" 4 |
|
|
1927 | .IX Item "EV_USE_SELECT" |
|
|
1928 | If undefined or defined to be \f(CW1\fR, libev will compile in support for the |
|
|
1929 | \&\f(CW\*(C`select\*(C'\fR(2) backend. No attempt at autodetection will be done: if no |
|
|
1930 | other method takes over, select will be it. Otherwise the select backend |
|
|
1931 | will not be compiled in. |
|
|
1932 | .IP "\s-1EV_SELECT_USE_FD_SET\s0" 4 |
|
|
1933 | .IX Item "EV_SELECT_USE_FD_SET" |
|
|
1934 | If defined to \f(CW1\fR, then the select backend will use the system \f(CW\*(C`fd_set\*(C'\fR |
|
|
1935 | structure. This is useful if libev doesn't compile due to a missing |
|
|
1936 | \&\f(CW\*(C`NFDBITS\*(C'\fR or \f(CW\*(C`fd_mask\*(C'\fR definition or it misguesses the bitset layout on |
|
|
1937 | exotic systems. This usually limits the range of file descriptors to some |
|
|
1938 | low limit such as 1024 or might have other limitations (winsocket only |
|
|
1939 | allows 64 sockets). The \f(CW\*(C`FD_SETSIZE\*(C'\fR macro, set before compilation, might |
|
|
1940 | influence the size of the \f(CW\*(C`fd_set\*(C'\fR used. |
|
|
1941 | .IP "\s-1EV_SELECT_IS_WINSOCKET\s0" 4 |
|
|
1942 | .IX Item "EV_SELECT_IS_WINSOCKET" |
|
|
1943 | When defined to \f(CW1\fR, the select backend will assume that |
|
|
1944 | select/socket/connect etc. don't understand file descriptors but |
|
|
1945 | wants osf handles on win32 (this is the case when the select to |
|
|
1946 | be used is the winsock select). This means that it will call |
|
|
1947 | \&\f(CW\*(C`_get_osfhandle\*(C'\fR on the fd to convert it to an \s-1OS\s0 handle. Otherwise, |
|
|
1948 | it is assumed that all these functions actually work on fds, even |
|
|
1949 | on win32. Should not be defined on non\-win32 platforms. |
|
|
1950 | .IP "\s-1EV_USE_POLL\s0" 4 |
|
|
1951 | .IX Item "EV_USE_POLL" |
|
|
1952 | If defined to be \f(CW1\fR, libev will compile in support for the \f(CW\*(C`poll\*(C'\fR(2) |
|
|
1953 | backend. Otherwise it will be enabled on non\-win32 platforms. It |
|
|
1954 | takes precedence over select. |
|
|
1955 | .IP "\s-1EV_USE_EPOLL\s0" 4 |
|
|
1956 | .IX Item "EV_USE_EPOLL" |
|
|
1957 | If defined to be \f(CW1\fR, libev will compile in support for the Linux |
|
|
1958 | \&\f(CW\*(C`epoll\*(C'\fR(7) backend. Its availability will be detected at runtime, |
|
|
1959 | otherwise another method will be used as fallback. This is the |
|
|
1960 | preferred backend for GNU/Linux systems. |
|
|
1961 | .IP "\s-1EV_USE_KQUEUE\s0" 4 |
|
|
1962 | .IX Item "EV_USE_KQUEUE" |
|
|
1963 | If defined to be \f(CW1\fR, libev will compile in support for the \s-1BSD\s0 style |
|
|
1964 | \&\f(CW\*(C`kqueue\*(C'\fR(2) backend. Its actual availability will be detected at runtime, |
|
|
1965 | otherwise another method will be used as fallback. This is the preferred |
|
|
1966 | backend for \s-1BSD\s0 and BSD-like systems, although on most BSDs kqueue only |
|
|
1967 | supports some types of fds correctly (the only platform we found that |
|
|
1968 | supports ptys for example was NetBSD), so kqueue might be compiled in, but |
|
|
1969 | not be used unless explicitly requested. The best way to use it is to find |
|
|
1970 | out whether kqueue supports your type of fd properly and use an embedded |
|
|
1971 | kqueue loop. |
|
|
1972 | .IP "\s-1EV_USE_PORT\s0" 4 |
|
|
1973 | .IX Item "EV_USE_PORT" |
|
|
1974 | If defined to be \f(CW1\fR, libev will compile in support for the Solaris |
|
|
1975 | 10 port style backend. Its availability will be detected at runtime, |
|
|
1976 | otherwise another method will be used as fallback. This is the preferred |
|
|
1977 | backend for Solaris 10 systems. |
|
|
1978 | .IP "\s-1EV_USE_DEVPOLL\s0" 4 |
|
|
1979 | .IX Item "EV_USE_DEVPOLL" |
|
|
1980 | reserved for future expansion, works like the \s-1USE\s0 symbols above. |
|
|
1981 | .IP "\s-1EV_H\s0" 4 |
|
|
1982 | .IX Item "EV_H" |
|
|
1983 | The name of the \fIev.h\fR header file used to include it. The default if |
|
|
1984 | undefined is \f(CW\*(C`<ev.h>\*(C'\fR in \fIevent.h\fR and \f(CW"ev.h"\fR in \fIev.c\fR. This |
|
|
1985 | can be used to virtually rename the \fIev.h\fR header file in case of conflicts. |
|
|
1986 | .IP "\s-1EV_CONFIG_H\s0" 4 |
|
|
1987 | .IX Item "EV_CONFIG_H" |
|
|
1988 | If \f(CW\*(C`EV_STANDALONE\*(C'\fR isn't \f(CW1\fR, this variable can be used to override |
|
|
1989 | \&\fIev.c\fR's idea of where to find the \fIconfig.h\fR file, similarly to |
|
|
1990 | \&\f(CW\*(C`EV_H\*(C'\fR, above. |
|
|
1991 | .IP "\s-1EV_EVENT_H\s0" 4 |
|
|
1992 | .IX Item "EV_EVENT_H" |
|
|
1993 | Similarly to \f(CW\*(C`EV_H\*(C'\fR, this macro can be used to override \fIevent.c\fR's idea |
|
|
1994 | of how the \fIevent.h\fR header can be found. |
|
|
1995 | .IP "\s-1EV_PROTOTYPES\s0" 4 |
|
|
1996 | .IX Item "EV_PROTOTYPES" |
|
|
1997 | If defined to be \f(CW0\fR, then \fIev.h\fR will not define any function |
|
|
1998 | prototypes, but still define all the structs and other symbols. This is |
|
|
1999 | occasionally useful if you want to provide your own wrapper functions |
|
|
2000 | around libev functions. |
|
|
2001 | .IP "\s-1EV_MULTIPLICITY\s0" 4 |
|
|
2002 | .IX Item "EV_MULTIPLICITY" |
|
|
2003 | If undefined or defined to \f(CW1\fR, then all event-loop-specific functions |
|
|
2004 | will have the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument, and you can create |
|
|
2005 | additional independent event loops. Otherwise there will be no support |
|
|
2006 | for multiple event loops and there is no first event loop pointer |
|
|
2007 | argument. Instead, all functions act on the single default loop. |
|
|
2008 | .IP "\s-1EV_PERIODIC_ENABLE\s0" 4 |
|
|
2009 | .IX Item "EV_PERIODIC_ENABLE" |
|
|
2010 | If undefined or defined to be \f(CW1\fR, then periodic timers are supported. If |
|
|
2011 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
|
|
2012 | code. |
|
|
2013 | .IP "\s-1EV_EMBED_ENABLE\s0" 4 |
|
|
2014 | .IX Item "EV_EMBED_ENABLE" |
|
|
2015 | If undefined or defined to be \f(CW1\fR, then embed watchers are supported. If |
|
|
2016 | defined to be \f(CW0\fR, then they are not. |
|
|
2017 | .IP "\s-1EV_STAT_ENABLE\s0" 4 |
|
|
2018 | .IX Item "EV_STAT_ENABLE" |
|
|
2019 | If undefined or defined to be \f(CW1\fR, then stat watchers are supported. If |
|
|
2020 | defined to be \f(CW0\fR, then they are not. |
|
|
2021 | .IP "\s-1EV_MINIMAL\s0" 4 |
|
|
2022 | .IX Item "EV_MINIMAL" |
|
|
2023 | If you need to shave off some kilobytes of code at the expense of some |
|
|
2024 | speed, define this symbol to \f(CW1\fR. Currently only used for gcc to override |
|
|
2025 | some inlining decisions, saves roughly 30% codesize of amd64. |
|
|
2026 | .IP "\s-1EV_COMMON\s0" 4 |
|
|
2027 | .IX Item "EV_COMMON" |
|
|
2028 | By default, all watchers have a \f(CW\*(C`void *data\*(C'\fR member. By redefining |
|
|
2029 | this macro to a something else you can include more and other types of |
|
|
2030 | members. You have to define it each time you include one of the files, |
|
|
2031 | though, and it must be identical each time. |
|
|
2032 | .Sp |
|
|
2033 | For example, the perl \s-1EV\s0 module uses something like this: |
|
|
2034 | .Sp |
|
|
2035 | .Vb 3 |
|
|
2036 | \& #define EV_COMMON \e |
|
|
2037 | \& SV *self; /* contains this struct */ \e |
|
|
2038 | \& SV *cb_sv, *fh /* note no trailing ";" */ |
|
|
2039 | .Ve |
|
|
2040 | .IP "\s-1EV_CB_DECLARE\s0 (type)" 4 |
|
|
2041 | .IX Item "EV_CB_DECLARE (type)" |
|
|
2042 | .PD 0 |
|
|
2043 | .IP "\s-1EV_CB_INVOKE\s0 (watcher, revents)" 4 |
|
|
2044 | .IX Item "EV_CB_INVOKE (watcher, revents)" |
|
|
2045 | .IP "ev_set_cb (ev, cb)" 4 |
|
|
2046 | .IX Item "ev_set_cb (ev, cb)" |
|
|
2047 | .PD |
|
|
2048 | Can be used to change the callback member declaration in each watcher, |
|
|
2049 | and the way callbacks are invoked and set. Must expand to a struct member |
|
|
2050 | definition and a statement, respectively. See the \fIev.v\fR header file for |
|
|
2051 | their default definitions. One possible use for overriding these is to |
|
|
2052 | avoid the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument in all cases, or to use |
|
|
2053 | method calls instead of plain function calls in \*(C+. |
|
|
2054 | .Sh "\s-1EXAMPLES\s0" |
|
|
2055 | .IX Subsection "EXAMPLES" |
|
|
2056 | For a real-world example of a program the includes libev |
|
|
2057 | verbatim, you can have a look at the \s-1EV\s0 perl module |
|
|
2058 | (<http://software.schmorp.de/pkg/EV.html>). It has the libev files in |
|
|
2059 | the \fIlibev/\fR subdirectory and includes them in the \fI\s-1EV/EVAPI\s0.h\fR (public |
|
|
2060 | interface) and \fI\s-1EV\s0.xs\fR (implementation) files. Only the \fI\s-1EV\s0.xs\fR file |
|
|
2061 | will be compiled. It is pretty complex because it provides its own header |
|
|
2062 | file. |
|
|
2063 | .Sp |
|
|
2064 | The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file |
|
|
2065 | that everybody includes and which overrides some autoconf choices: |
|
|
2066 | .Sp |
|
|
2067 | .Vb 4 |
|
|
2068 | \& #define EV_USE_POLL 0 |
|
|
2069 | \& #define EV_MULTIPLICITY 0 |
|
|
2070 | \& #define EV_PERIODICS 0 |
|
|
2071 | \& #define EV_CONFIG_H <config.h> |
|
|
2072 | .Ve |
|
|
2073 | .Sp |
|
|
2074 | .Vb 1 |
|
|
2075 | \& #include "ev++.h" |
|
|
2076 | .Ve |
|
|
2077 | .Sp |
|
|
2078 | And a \fIev_cpp.C\fR implementation file that contains libev proper and is compiled: |
|
|
2079 | .Sp |
|
|
2080 | .Vb 2 |
|
|
2081 | \& #include "ev_cpp.h" |
|
|
2082 | \& #include "ev.c" |
|
|
2083 | .Ve |
|
|
2084 | .SH "COMPLEXITIES" |
|
|
2085 | .IX Header "COMPLEXITIES" |
|
|
2086 | In this section the complexities of (many of) the algorithms used inside |
|
|
2087 | libev will be explained. For complexity discussions about backends see the |
|
|
2088 | documentation for \f(CW\*(C`ev_default_init\*(C'\fR. |
|
|
2089 | .RS 4 |
|
|
2090 | .IP "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" 4 |
|
|
2091 | .IX Item "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" |
|
|
2092 | .PD 0 |
|
|
2093 | .IP "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" 4 |
|
|
2094 | .IX Item "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" |
|
|
2095 | .IP "Starting io/check/prepare/idle/signal/child watchers: O(1)" 4 |
|
|
2096 | .IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)" |
|
|
2097 | .IP "Stopping check/prepare/idle watchers: O(1)" 4 |
|
|
2098 | .IX Item "Stopping check/prepare/idle watchers: O(1)" |
|
|
2099 | .IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % 16))" 4 |
|
|
2100 | .IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % 16))" |
|
|
2101 | .IP "Finding the next timer per loop iteration: O(1)" 4 |
|
|
2102 | .IX Item "Finding the next timer per loop iteration: O(1)" |
|
|
2103 | .IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4 |
|
|
2104 | .IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" |
|
|
2105 | .IP "Activating one watcher: O(1)" 4 |
|
|
2106 | .IX Item "Activating one watcher: O(1)" |
|
|
2107 | .RE |
|
|
2108 | .RS 4 |
|
|
2109 | .PD |
958 | .SH "AUTHOR" |
2110 | .SH "AUTHOR" |
959 | .IX Header "AUTHOR" |
2111 | .IX Header "AUTHOR" |
960 | Marc Lehmann <libev@schmorp.de>. |
2112 | Marc Lehmann <libev@schmorp.de>. |