… | |
… | |
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 "2007-11-18" "perl v5.8.8" "User Contributed Perl Documentation" |
132 | .TH "<STANDARD INPUT>" 1 "2007-11-24" "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 |
… | |
… | |
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 |
… | |
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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"" (portable select backend)" 4 |
350 | .ie n .IP """EVBACKEND_SELECT"" (value 1, portable select backend)" 4 |
266 | .el .IP "\f(CWEVMETHOD_SELECT\fR (portable select backend)" 4 |
351 | .el .IP "\f(CWEVBACKEND_SELECT\fR (value 1, portable select backend)" 4 |
267 | .IX Item "EVMETHOD_SELECT (portable select backend)" |
352 | .IX Item "EVBACKEND_SELECT (value 1, portable select backend)" |
268 | .PD 0 |
353 | This is your standard \fIselect\fR\|(2) backend. Not \fIcompletely\fR standard, as |
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354 | libev tries to roll its own fd_set with no limits on the number of fds, |
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355 | but if that fails, expect a fairly low limit on the number of fds when |
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356 | using this backend. It doesn't scale too well (O(highest_fd)), but its usually |
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357 | the fastest backend for a low number of fds. |
269 | .ie n .IP """EVMETHOD_POLL"" (poll backend, available everywhere except on windows)" 4 |
358 | .ie n .IP """EVBACKEND_POLL"" (value 2, poll backend, available everywhere except on windows)" 4 |
270 | .el .IP "\f(CWEVMETHOD_POLL\fR (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 |
271 | .IX Item "EVMETHOD_POLL (poll backend, available everywhere except on windows)" |
360 | .IX Item "EVBACKEND_POLL (value 2, poll backend, available everywhere except on windows)" |
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361 | And this is your standard \fIpoll\fR\|(2) backend. It's more complicated than |
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362 | select, but handles sparse fds better and has no artificial limit on the |
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363 | number of fds you can use (except it will slow down considerably with a |
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364 | lot of inactive fds). It scales similarly to select, i.e. O(total_fds). |
272 | .ie n .IP """EVMETHOD_EPOLL"" (linux only)" 4 |
365 | .ie n .IP """EVBACKEND_EPOLL"" (value 4, Linux)" 4 |
273 | .el .IP "\f(CWEVMETHOD_EPOLL\fR (linux only)" 4 |
366 | .el .IP "\f(CWEVBACKEND_EPOLL\fR (value 4, Linux)" 4 |
274 | .IX Item "EVMETHOD_EPOLL (linux only)" |
367 | .IX Item "EVBACKEND_EPOLL (value 4, Linux)" |
275 | .ie n .IP """EVMETHOD_KQUEUE"" (some bsds only)" 4 |
368 | For few fds, this backend is a bit little slower than poll and select, |
276 | .el .IP "\f(CWEVMETHOD_KQUEUE\fR (some bsds only)" 4 |
369 | but it scales phenomenally better. While poll and select usually scale like |
277 | .IX Item "EVMETHOD_KQUEUE (some bsds only)" |
370 | O(total_fds) where n is the total number of fds (or the highest fd), epoll scales |
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371 | either O(1) or O(active_fds). |
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372 | .Sp |
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373 | While stopping and starting an I/O watcher in the same iteration will |
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374 | result in some caching, there is still a syscall per such incident |
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375 | (because the fd could point to a different file description now), so its |
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376 | best to avoid that. Also, \fIdup()\fRed file descriptors might not work very |
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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. |
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382 | .ie n .IP """EVBACKEND_KQUEUE"" (value 8, most \s-1BSD\s0 clones)" 4 |
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383 | .el .IP "\f(CWEVBACKEND_KQUEUE\fR (value 8, most \s-1BSD\s0 clones)" 4 |
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384 | .IX Item "EVBACKEND_KQUEUE (value 8, most BSD clones)" |
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385 | Kqueue deserves special mention, as at the time of this writing, it |
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386 | was broken on all BSDs except NetBSD (usually it doesn't work with |
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387 | anything but sockets and pipes, except on Darwin, where of course its |
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388 | completely useless). For this reason its not being \*(L"autodetected\*(R" |
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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). |
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391 | .Sp |
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392 | It scales in the same way as the epoll backend, but the interface to the |
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393 | kernel is more efficient (which says nothing about its actual speed, of |
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394 | course). While starting and stopping an I/O watcher does not cause an |
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395 | extra syscall as with epoll, it still adds up to four event changes per |
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396 | incident, so its best to avoid that. |
278 | .ie n .IP """EVMETHOD_DEVPOLL"" (solaris 8 only)" 4 |
397 | .ie n .IP """EVBACKEND_DEVPOLL"" (value 16, Solaris 8)" 4 |
279 | .el .IP "\f(CWEVMETHOD_DEVPOLL\fR (solaris 8 only)" 4 |
398 | .el .IP "\f(CWEVBACKEND_DEVPOLL\fR (value 16, Solaris 8)" 4 |
280 | .IX Item "EVMETHOD_DEVPOLL (solaris 8 only)" |
399 | .IX Item "EVBACKEND_DEVPOLL (value 16, Solaris 8)" |
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400 | This is not implemented yet (and might never be). |
281 | .ie n .IP """EVMETHOD_PORT"" (solaris 10 only)" 4 |
401 | .ie n .IP """EVBACKEND_PORT"" (value 32, Solaris 10)" 4 |
282 | .el .IP "\f(CWEVMETHOD_PORT\fR (solaris 10 only)" 4 |
402 | .el .IP "\f(CWEVBACKEND_PORT\fR (value 32, Solaris 10)" 4 |
283 | .IX Item "EVMETHOD_PORT (solaris 10 only)" |
403 | .IX Item "EVBACKEND_PORT (value 32, Solaris 10)" |
284 | .PD |
404 | This uses the Solaris 10 port mechanism. As with everything on Solaris, |
285 | If one or more of these are ored into the flags value, then only these |
405 | it's really slow, but it still scales very well (O(active_fds)). |
286 | backends will be tried (in the reverse order as given here). If one are |
406 | .Sp |
287 | specified, any backend will do. |
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. |
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410 | .ie n .IP """EVBACKEND_ALL""" 4 |
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411 | .el .IP "\f(CWEVBACKEND_ALL\fR" 4 |
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412 | .IX Item "EVBACKEND_ALL" |
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413 | Try all backends (even potentially broken ones that wouldn't be tried |
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414 | with \f(CW\*(C`EVFLAG_AUTO\*(C'\fR). Since this is a mask, you can do stuff such as |
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415 | \&\f(CW\*(C`EVBACKEND_ALL & ~EVBACKEND_KQUEUE\*(C'\fR. |
288 | .RE |
416 | .RE |
289 | .RS 4 |
417 | .RS 4 |
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418 | .Sp |
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419 | If one or more of these are ored into the flags value, then only these |
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420 | backends will be tried (in the reverse order as given here). If none are |
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421 | specified, most compiled-in backend will be tried, usually in reverse |
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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 |
290 | .RE |
445 | .RE |
291 | .IP "struct ev_loop *ev_loop_new (unsigned int flags)" 4 |
446 | .IP "struct ev_loop *ev_loop_new (unsigned int flags)" 4 |
292 | .IX Item "struct ev_loop *ev_loop_new (unsigned int flags)" |
447 | .IX Item "struct ev_loop *ev_loop_new (unsigned int flags)" |
293 | 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 |
294 | 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 |
295 | 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 |
296 | undefined behaviour (or a failed assertion if assertions are enabled). |
451 | undefined behaviour (or a failed assertion if assertions are enabled). |
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452 | .Sp |
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453 | Example: try to create a event loop that uses epoll and nothing else. |
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454 | .Sp |
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455 | .Vb 3 |
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456 | \& struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
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457 | \& if (!epoller) |
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458 | \& fatal ("no epoll found here, maybe it hides under your chair"); |
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459 | .Ve |
297 | .IP "ev_default_destroy ()" 4 |
460 | .IP "ev_default_destroy ()" 4 |
298 | .IX Item "ev_default_destroy ()" |
461 | .IX Item "ev_default_destroy ()" |
299 | Destroys the default loop again (frees all memory and kernel state |
462 | Destroys the default loop again (frees all memory and kernel state |
300 | 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 |
301 | 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 |
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465 | responsibility to either stop all watchers cleanly yoursef \fIbefore\fR |
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466 | calling this function, or cope with the fact afterwards (which is usually |
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467 | the easiest thing, youc na just ignore the watchers and/or \f(CW\*(C`free ()\*(C'\fR them |
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468 | for example). |
302 | .IP "ev_loop_destroy (loop)" 4 |
469 | .IP "ev_loop_destroy (loop)" 4 |
303 | .IX Item "ev_loop_destroy (loop)" |
470 | .IX Item "ev_loop_destroy (loop)" |
304 | 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 |
305 | earlier call to \f(CW\*(C`ev_loop_new\*(C'\fR. |
472 | earlier call to \f(CW\*(C`ev_loop_new\*(C'\fR. |
306 | .IP "ev_default_fork ()" 4 |
473 | .IP "ev_default_fork ()" 4 |
… | |
… | |
308 | This function reinitialises the kernel state for backends that have |
475 | This function reinitialises the kernel state for backends that have |
309 | 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 |
310 | 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 |
311 | again makes little sense). |
478 | again makes little sense). |
312 | .Sp |
479 | .Sp |
313 | 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 |
314 | 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 |
315 | have to call it. |
482 | fork+exec, you don't have to call it. |
316 | .Sp |
483 | .Sp |
317 | 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 |
318 | 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 |
319 | 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: |
320 | .Sp |
487 | .Sp |
321 | .Vb 1 |
488 | .Vb 1 |
322 | \& pthread_atfork (0, 0, ev_default_fork); |
489 | \& pthread_atfork (0, 0, ev_default_fork); |
323 | .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. |
324 | .IP "ev_loop_fork (loop)" 4 |
495 | .IP "ev_loop_fork (loop)" 4 |
325 | .IX Item "ev_loop_fork (loop)" |
496 | .IX Item "ev_loop_fork (loop)" |
326 | 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 |
327 | \&\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 |
328 | 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. |
329 | .IP "unsigned int ev_method (loop)" 4 |
500 | .IP "unsigned int ev_backend (loop)" 4 |
330 | .IX Item "unsigned int ev_method (loop)" |
501 | .IX Item "unsigned int ev_backend (loop)" |
331 | 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 |
332 | use. |
503 | use. |
333 | .IP "ev_tstamp ev_now (loop)" 4 |
504 | .IP "ev_tstamp ev_now (loop)" 4 |
334 | .IX Item "ev_tstamp ev_now (loop)" |
505 | .IX Item "ev_tstamp ev_now (loop)" |
335 | 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 |
336 | got events and started processing them. This timestamp does not change |
507 | received events and started processing them. This timestamp does not |
337 | 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 |
338 | 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 |
339 | occuring (or more correctly, the mainloop finding out about it). |
510 | event occuring (or more correctly, libev finding out about it). |
340 | .IP "ev_loop (loop, int flags)" 4 |
511 | .IP "ev_loop (loop, int flags)" 4 |
341 | .IX Item "ev_loop (loop, int flags)" |
512 | .IX Item "ev_loop (loop, int flags)" |
342 | 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 |
343 | 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 |
344 | events. |
515 | events. |
345 | .Sp |
516 | .Sp |
346 | 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 |
347 | 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. |
348 | .Sp |
525 | .Sp |
349 | 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 |
350 | 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 |
351 | 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. |
352 | .Sp |
529 | .Sp |
353 | 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 |
354 | 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 |
355 | 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 |
356 | 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. |
357 | .Sp |
537 | .Sp |
358 | This flags value could be used to implement alternative looping |
|
|
359 | constructs, but the \f(CW\*(C`prepare\*(C'\fR and \f(CW\*(C`check\*(C'\fR watchers provide a better and |
|
|
360 | more generic mechanism. |
|
|
361 | .Sp |
|
|
362 | 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: |
363 | .Sp |
539 | .Sp |
364 | .Vb 15 |
540 | .Vb 18 |
365 | \& 1. If there are no active watchers (reference count is zero), return. |
541 | \& * If there are no active watchers (reference count is zero), return. |
366 | \& 2. Queue and immediately call all prepare watchers. |
542 | \& - Queue prepare watchers and then call all outstanding watchers. |
367 | \& 3. If we have been forked, recreate the kernel state. |
543 | \& - If we have been forked, recreate the kernel state. |
368 | \& 4. Update the kernel state with all outstanding changes. |
544 | \& - Update the kernel state with all outstanding changes. |
369 | \& 5. Update the "event loop time". |
545 | \& - Update the "event loop time". |
370 | \& 6. Calculate for how long to block. |
546 | \& - Calculate for how long to block. |
371 | \& 7. Block the process, waiting for events. |
547 | \& - Block the process, waiting for any events. |
|
|
548 | \& - Queue all outstanding I/O (fd) events. |
372 | \& 8. Update the "event loop time" and do time jump handling. |
549 | \& - Update the "event loop time" and do time jump handling. |
373 | \& 9. Queue all outstanding timers. |
550 | \& - Queue all outstanding timers. |
374 | \& 10. Queue all outstanding periodics. |
551 | \& - Queue all outstanding periodics. |
375 | \& 11. If no events are pending now, queue all idle watchers. |
552 | \& - If no events are pending now, queue all idle watchers. |
376 | \& 12. Queue all check watchers. |
553 | \& - Queue all check watchers. |
377 | \& 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. |
378 | \& 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 |
379 | \& 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! |
380 | .Ve |
569 | .Ve |
381 | .IP "ev_unloop (loop, how)" 4 |
570 | .IP "ev_unloop (loop, how)" 4 |
382 | .IX Item "ev_unloop (loop, how)" |
571 | .IX Item "ev_unloop (loop, how)" |
383 | 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 |
384 | 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 |
… | |
… | |
398 | 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 |
399 | 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 |
400 | 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 |
401 | 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 |
402 | 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 |
403 | .SH "ANATOMY OF A WATCHER" |
609 | .SH "ANATOMY OF A WATCHER" |
404 | .IX Header "ANATOMY OF A WATCHER" |
610 | .IX Header "ANATOMY OF A WATCHER" |
405 | 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 |
406 | 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 |
407 | 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: |
… | |
… | |
443 | *)\*(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 |
444 | 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. |
445 | .PP |
651 | .PP |
446 | 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 |
447 | 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 |
448 | reinitialise it or call its set method. |
654 | reinitialise it or call its \f(CW\*(C`set\*(C'\fR macro. |
449 | .PP |
|
|
450 | You can check whether an event is active by calling the \f(CW\*(C`ev_is_active |
|
|
451 | (watcher *)\*(C'\fR macro. To see whether an event is outstanding (but the |
|
|
452 | callback for it has not been called yet) you can use the \f(CW\*(C`ev_is_pending |
|
|
453 | (watcher *)\*(C'\fR macro. |
|
|
454 | .PP |
655 | .PP |
455 | 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 |
456 | 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 |
457 | third argument. |
658 | third argument. |
458 | .PP |
659 | .PP |
… | |
… | |
516 | Libev will usually signal a few \*(L"dummy\*(R" events together with an error, |
717 | Libev will usually signal a few \*(L"dummy\*(R" events together with an error, |
517 | for example it might indicate that a fd is readable or writable, and if |
718 | for example it might indicate that a fd is readable or writable, and if |
518 | your callbacks is well-written it can just attempt the operation and cope |
719 | your callbacks is well-written it can just attempt the operation and cope |
519 | with the error from \fIread()\fR or \fIwrite()\fR. This will not work in multithreaded |
720 | with the error from \fIread()\fR or \fIwrite()\fR. This will not work in multithreaded |
520 | programs, though, so beware. |
721 | programs, though, so beware. |
|
|
722 | .Sh "\s-1GENERIC\s0 \s-1WATCHER\s0 \s-1FUNCTIONS\s0" |
|
|
723 | .IX Subsection "GENERIC WATCHER FUNCTIONS" |
|
|
724 | In the following description, \f(CW\*(C`TYPE\*(C'\fR stands for the watcher type, |
|
|
725 | 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. |
|
|
726 | .ie n .IP """ev_init"" (ev_TYPE *watcher, callback)" 4 |
|
|
727 | .el .IP "\f(CWev_init\fR (ev_TYPE *watcher, callback)" 4 |
|
|
728 | .IX Item "ev_init (ev_TYPE *watcher, callback)" |
|
|
729 | This macro initialises the generic portion of a watcher. The contents |
|
|
730 | of the watcher object can be arbitrary (so \f(CW\*(C`malloc\*(C'\fR will do). Only |
|
|
731 | the generic parts of the watcher are initialised, you \fIneed\fR to call |
|
|
732 | the type-specific \f(CW\*(C`ev_TYPE_set\*(C'\fR macro afterwards to initialise the |
|
|
733 | type-specific parts. For each type there is also a \f(CW\*(C`ev_TYPE_init\*(C'\fR macro |
|
|
734 | which rolls both calls into one. |
|
|
735 | .Sp |
|
|
736 | You can reinitialise a watcher at any time as long as it has been stopped |
|
|
737 | (or never started) and there are no pending events outstanding. |
|
|
738 | .Sp |
|
|
739 | The callback is always of type \f(CW\*(C`void (*)(ev_loop *loop, ev_TYPE *watcher, |
|
|
740 | int revents)\*(C'\fR. |
|
|
741 | .ie n .IP """ev_TYPE_set"" (ev_TYPE *, [args])" 4 |
|
|
742 | .el .IP "\f(CWev_TYPE_set\fR (ev_TYPE *, [args])" 4 |
|
|
743 | .IX Item "ev_TYPE_set (ev_TYPE *, [args])" |
|
|
744 | This macro initialises the type-specific parts of a watcher. You need to |
|
|
745 | call \f(CW\*(C`ev_init\*(C'\fR at least once before you call this macro, but you can |
|
|
746 | call \f(CW\*(C`ev_TYPE_set\*(C'\fR any number of times. You must not, however, call this |
|
|
747 | macro on a watcher that is active (it can be pending, however, which is a |
|
|
748 | difference to the \f(CW\*(C`ev_init\*(C'\fR macro). |
|
|
749 | .Sp |
|
|
750 | Although some watcher types do not have type-specific arguments |
|
|
751 | (e.g. \f(CW\*(C`ev_prepare\*(C'\fR) you still need to call its \f(CW\*(C`set\*(C'\fR macro. |
|
|
752 | .ie n .IP """ev_TYPE_init"" (ev_TYPE *watcher, callback, [args])" 4 |
|
|
753 | .el .IP "\f(CWev_TYPE_init\fR (ev_TYPE *watcher, callback, [args])" 4 |
|
|
754 | .IX Item "ev_TYPE_init (ev_TYPE *watcher, callback, [args])" |
|
|
755 | This convinience macro rolls both \f(CW\*(C`ev_init\*(C'\fR and \f(CW\*(C`ev_TYPE_set\*(C'\fR macro |
|
|
756 | calls into a single call. This is the most convinient method to initialise |
|
|
757 | a watcher. The same limitations apply, of course. |
|
|
758 | .ie n .IP """ev_TYPE_start"" (loop *, ev_TYPE *watcher)" 4 |
|
|
759 | .el .IP "\f(CWev_TYPE_start\fR (loop *, ev_TYPE *watcher)" 4 |
|
|
760 | .IX Item "ev_TYPE_start (loop *, ev_TYPE *watcher)" |
|
|
761 | Starts (activates) the given watcher. Only active watchers will receive |
|
|
762 | events. If the watcher is already active nothing will happen. |
|
|
763 | .ie n .IP """ev_TYPE_stop"" (loop *, ev_TYPE *watcher)" 4 |
|
|
764 | .el .IP "\f(CWev_TYPE_stop\fR (loop *, ev_TYPE *watcher)" 4 |
|
|
765 | .IX Item "ev_TYPE_stop (loop *, ev_TYPE *watcher)" |
|
|
766 | Stops the given watcher again (if active) and clears the pending |
|
|
767 | status. It is possible that stopped watchers are pending (for example, |
|
|
768 | non-repeating timers are being stopped when they become pending), but |
|
|
769 | \&\f(CW\*(C`ev_TYPE_stop\*(C'\fR ensures that the watcher is neither active nor pending. If |
|
|
770 | you want to free or reuse the memory used by the watcher it is therefore a |
|
|
771 | good idea to always call its \f(CW\*(C`ev_TYPE_stop\*(C'\fR function. |
|
|
772 | .IP "bool ev_is_active (ev_TYPE *watcher)" 4 |
|
|
773 | .IX Item "bool ev_is_active (ev_TYPE *watcher)" |
|
|
774 | Returns a true value iff the watcher is active (i.e. it has been started |
|
|
775 | and not yet been stopped). As long as a watcher is active you must not modify |
|
|
776 | it. |
|
|
777 | .IP "bool ev_is_pending (ev_TYPE *watcher)" 4 |
|
|
778 | .IX Item "bool ev_is_pending (ev_TYPE *watcher)" |
|
|
779 | Returns a true value iff the watcher is pending, (i.e. it has outstanding |
|
|
780 | events but its callback has not yet been invoked). As long as a watcher |
|
|
781 | is pending (but not active) you must not call an init function on it (but |
|
|
782 | \&\f(CW\*(C`ev_TYPE_set\*(C'\fR is safe) and you must make sure the watcher is available to |
|
|
783 | libev (e.g. you cnanot \f(CW\*(C`free ()\*(C'\fR it). |
|
|
784 | .IP "callback = ev_cb (ev_TYPE *watcher)" 4 |
|
|
785 | .IX Item "callback = ev_cb (ev_TYPE *watcher)" |
|
|
786 | Returns the callback currently set on the watcher. |
|
|
787 | .IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 |
|
|
788 | .IX Item "ev_cb_set (ev_TYPE *watcher, callback)" |
|
|
789 | Change the callback. You can change the callback at virtually any time |
|
|
790 | (modulo threads). |
521 | .Sh "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0" |
791 | .Sh "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0" |
522 | .IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER" |
792 | .IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER" |
523 | Each watcher has, by default, a member \f(CW\*(C`void *data\*(C'\fR that you can change |
793 | Each watcher has, by default, a member \f(CW\*(C`void *data\*(C'\fR that you can change |
524 | and read at any time, libev will completely ignore it. This can be used |
794 | and read at any time, libev will completely ignore it. This can be used |
525 | to associate arbitrary data with your watcher. If you need more data and |
795 | to associate arbitrary data with your watcher. If you need more data and |
… | |
… | |
552 | have been omitted.... |
822 | have been omitted.... |
553 | .SH "WATCHER TYPES" |
823 | .SH "WATCHER TYPES" |
554 | .IX Header "WATCHER TYPES" |
824 | .IX Header "WATCHER TYPES" |
555 | This section describes each watcher in detail, but will not repeat |
825 | This section describes each watcher in detail, but will not repeat |
556 | information given in the last section. |
826 | information given in the last section. |
557 | .ie n .Sh """ev_io"" \- is this file descriptor readable or writable" |
827 | .ie n .Sh """ev_io"" \- is this file descriptor readable or writable?" |
558 | .el .Sh "\f(CWev_io\fP \- is this file descriptor readable or writable" |
828 | .el .Sh "\f(CWev_io\fP \- is this file descriptor readable or writable?" |
559 | .IX Subsection "ev_io - is this file descriptor readable or writable" |
829 | .IX Subsection "ev_io - is this file descriptor readable or writable?" |
560 | I/O watchers check whether a file descriptor is readable or writable |
830 | I/O watchers check whether a file descriptor is readable or writable |
561 | in each iteration of the event loop (This behaviour is called |
831 | in each iteration of the event loop, or, more precisely, when reading |
562 | level-triggering because you keep receiving events as long as the |
832 | would not block the process and writing would at least be able to write |
563 | condition persists. Remember you can stop the watcher if you don't want to |
833 | some data. This behaviour is called level-triggering because you keep |
564 | act on the event and neither want to receive future events). |
834 | receiving events as long as the condition persists. Remember you can stop |
|
|
835 | the watcher if you don't want to act on the event and neither want to |
|
|
836 | receive future events. |
565 | .PP |
837 | .PP |
566 | In general you can register as many read and/or write event watchers per |
838 | In general you can register as many read and/or write event watchers per |
567 | fd as you want (as long as you don't confuse yourself). Setting all file |
839 | fd as you want (as long as you don't confuse yourself). Setting all file |
568 | descriptors to non-blocking mode is also usually a good idea (but not |
840 | descriptors to non-blocking mode is also usually a good idea (but not |
569 | required if you know what you are doing). |
841 | required if you know what you are doing). |
570 | .PP |
842 | .PP |
571 | You have to be careful with dup'ed file descriptors, though. Some backends |
843 | You have to be careful with dup'ed file descriptors, though. Some backends |
572 | (the linux epoll backend is a notable example) cannot handle dup'ed file |
844 | (the linux epoll backend is a notable example) cannot handle dup'ed file |
573 | descriptors correctly if you register interest in two or more fds pointing |
845 | descriptors correctly if you register interest in two or more fds pointing |
574 | to the same underlying file/socket etc. description (that is, they share |
846 | to the same underlying file/socket/etc. description (that is, they share |
575 | the same underlying \*(L"file open\*(R"). |
847 | the same underlying \*(L"file open\*(R"). |
576 | .PP |
848 | .PP |
577 | If you must do this, then force the use of a known-to-be-good backend |
849 | If you must do this, then force the use of a known-to-be-good backend |
578 | (at the time of this writing, this includes only \s-1EVMETHOD_SELECT\s0 and |
850 | (at the time of this writing, this includes only \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR and |
579 | \&\s-1EVMETHOD_POLL\s0). |
851 | \&\f(CW\*(C`EVBACKEND_POLL\*(C'\fR). |
|
|
852 | .PP |
|
|
853 | Another thing you have to watch out for is that it is quite easy to |
|
|
854 | receive \*(L"spurious\*(R" readyness notifications, that is your callback might |
|
|
855 | be called with \f(CW\*(C`EV_READ\*(C'\fR but a subsequent \f(CW\*(C`read\*(C'\fR(2) will actually block |
|
|
856 | because there is no data. Not only are some backends known to create a |
|
|
857 | lot of those (for example solaris ports), it is very easy to get into |
|
|
858 | this situation even with a relatively standard program structure. Thus |
|
|
859 | it is best to always use non-blocking I/O: An extra \f(CW\*(C`read\*(C'\fR(2) returning |
|
|
860 | \&\f(CW\*(C`EAGAIN\*(C'\fR is far preferable to a program hanging until some data arrives. |
|
|
861 | .PP |
|
|
862 | If you cannot run the fd in non-blocking mode (for example you should not |
|
|
863 | play around with an Xlib connection), then you have to seperately re-test |
|
|
864 | wether a file descriptor is really ready with a known-to-be good interface |
|
|
865 | such as poll (fortunately in our Xlib example, Xlib already does this on |
|
|
866 | its own, so its quite safe to use). |
580 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
867 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
581 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
868 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
582 | .PD 0 |
869 | .PD 0 |
583 | .IP "ev_io_set (ev_io *, int fd, int events)" 4 |
870 | .IP "ev_io_set (ev_io *, int fd, int events)" 4 |
584 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
871 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
585 | .PD |
872 | .PD |
586 | Configures an \f(CW\*(C`ev_io\*(C'\fR watcher. The fd is the file descriptor to rceeive |
873 | Configures an \f(CW\*(C`ev_io\*(C'\fR watcher. The \f(CW\*(C`fd\*(C'\fR is the file descriptor to |
587 | 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 | |
874 | rceeive events for and events is either \f(CW\*(C`EV_READ\*(C'\fR, \f(CW\*(C`EV_WRITE\*(C'\fR or |
588 | EV_WRITE\*(C'\fR to receive the given events. |
875 | \&\f(CW\*(C`EV_READ | EV_WRITE\*(C'\fR to receive the given events. |
|
|
876 | .PP |
|
|
877 | Example: call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well |
|
|
878 | readable, but only once. Since it is likely line\-buffered, you could |
|
|
879 | attempt to read a whole line in the callback: |
|
|
880 | .PP |
|
|
881 | .Vb 6 |
|
|
882 | \& static void |
|
|
883 | \& stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
|
|
884 | \& { |
|
|
885 | \& ev_io_stop (loop, w); |
|
|
886 | \& .. read from stdin here (or from w->fd) and haqndle any I/O errors |
|
|
887 | \& } |
|
|
888 | .Ve |
|
|
889 | .PP |
|
|
890 | .Vb 6 |
|
|
891 | \& ... |
|
|
892 | \& struct ev_loop *loop = ev_default_init (0); |
|
|
893 | \& struct ev_io stdin_readable; |
|
|
894 | \& ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ); |
|
|
895 | \& ev_io_start (loop, &stdin_readable); |
|
|
896 | \& ev_loop (loop, 0); |
|
|
897 | .Ve |
589 | .ie n .Sh """ev_timer"" \- relative and optionally recurring timeouts" |
898 | .ie n .Sh """ev_timer"" \- relative and optionally repeating timeouts" |
590 | .el .Sh "\f(CWev_timer\fP \- relative and optionally recurring timeouts" |
899 | .el .Sh "\f(CWev_timer\fP \- relative and optionally repeating timeouts" |
591 | .IX Subsection "ev_timer - relative and optionally recurring timeouts" |
900 | .IX Subsection "ev_timer - relative and optionally repeating timeouts" |
592 | Timer watchers are simple relative timers that generate an event after a |
901 | Timer watchers are simple relative timers that generate an event after a |
593 | given time, and optionally repeating in regular intervals after that. |
902 | given time, and optionally repeating in regular intervals after that. |
594 | .PP |
903 | .PP |
595 | The timers are based on real time, that is, if you register an event that |
904 | The timers are based on real time, that is, if you register an event that |
596 | times out after an hour and you reset your system clock to last years |
905 | times out after an hour and you reset your system clock to last years |
… | |
… | |
643 | seconds of inactivity on the socket. The easiest way to do this is to |
952 | seconds of inactivity on the socket. The easiest way to do this is to |
644 | configure an \f(CW\*(C`ev_timer\*(C'\fR with after=repeat=60 and calling ev_timer_again each |
953 | configure an \f(CW\*(C`ev_timer\*(C'\fR with after=repeat=60 and calling ev_timer_again each |
645 | time you successfully read or write some data. If you go into an idle |
954 | time you successfully read or write some data. If you go into an idle |
646 | state where you do not expect data to travel on the socket, you can stop |
955 | state where you do not expect data to travel on the socket, you can stop |
647 | the timer, and again will automatically restart it if need be. |
956 | the timer, and again will automatically restart it if need be. |
|
|
957 | .PP |
|
|
958 | Example: create a timer that fires after 60 seconds. |
|
|
959 | .PP |
|
|
960 | .Vb 5 |
|
|
961 | \& static void |
|
|
962 | \& one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
|
|
963 | \& { |
|
|
964 | \& .. one minute over, w is actually stopped right here |
|
|
965 | \& } |
|
|
966 | .Ve |
|
|
967 | .PP |
|
|
968 | .Vb 3 |
|
|
969 | \& struct ev_timer mytimer; |
|
|
970 | \& ev_timer_init (&mytimer, one_minute_cb, 60., 0.); |
|
|
971 | \& ev_timer_start (loop, &mytimer); |
|
|
972 | .Ve |
|
|
973 | .PP |
|
|
974 | Example: create a timeout timer that times out after 10 seconds of |
|
|
975 | inactivity. |
|
|
976 | .PP |
|
|
977 | .Vb 5 |
|
|
978 | \& static void |
|
|
979 | \& timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
|
|
980 | \& { |
|
|
981 | \& .. ten seconds without any activity |
|
|
982 | \& } |
|
|
983 | .Ve |
|
|
984 | .PP |
|
|
985 | .Vb 4 |
|
|
986 | \& struct ev_timer mytimer; |
|
|
987 | \& ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */ |
|
|
988 | \& ev_timer_again (&mytimer); /* start timer */ |
|
|
989 | \& ev_loop (loop, 0); |
|
|
990 | .Ve |
|
|
991 | .PP |
|
|
992 | .Vb 3 |
|
|
993 | \& // and in some piece of code that gets executed on any "activity": |
|
|
994 | \& // reset the timeout to start ticking again at 10 seconds |
|
|
995 | \& ev_timer_again (&mytimer); |
|
|
996 | .Ve |
648 | .ie n .Sh """ev_periodic"" \- to cron or not to cron" |
997 | .ie n .Sh """ev_periodic"" \- to cron or not to cron?" |
649 | .el .Sh "\f(CWev_periodic\fP \- to cron or not to cron" |
998 | .el .Sh "\f(CWev_periodic\fP \- to cron or not to cron?" |
650 | .IX Subsection "ev_periodic - to cron or not to cron" |
999 | .IX Subsection "ev_periodic - to cron or not to cron?" |
651 | Periodic watchers are also timers of a kind, but they are very versatile |
1000 | Periodic watchers are also timers of a kind, but they are very versatile |
652 | (and unfortunately a bit complex). |
1001 | (and unfortunately a bit complex). |
653 | .PP |
1002 | .PP |
654 | Unlike \f(CW\*(C`ev_timer\*(C'\fR's, they are not based on real time (or relative time) |
1003 | Unlike \f(CW\*(C`ev_timer\*(C'\fR's, they are not based on real time (or relative time) |
655 | but on wallclock time (absolute time). You can tell a periodic watcher |
1004 | but on wallclock time (absolute time). You can tell a periodic watcher |
656 | to trigger \*(L"at\*(R" some specific point in time. For example, if you tell a |
1005 | to trigger \*(L"at\*(R" some specific point in time. For example, if you tell a |
657 | periodic watcher to trigger in 10 seconds (by specifiying e.g. c<ev_now () |
1006 | periodic watcher to trigger in 10 seconds (by specifiying e.g. \f(CW\*(C`ev_now () |
658 | + 10.>) and then reset your system clock to the last year, then it will |
1007 | + 10.\*(C'\fR) and then reset your system clock to the last year, then it will |
659 | take a year to trigger the event (unlike an \f(CW\*(C`ev_timer\*(C'\fR, which would trigger |
1008 | take a year to trigger the event (unlike an \f(CW\*(C`ev_timer\*(C'\fR, which would trigger |
660 | roughly 10 seconds later and of course not if you reset your system time |
1009 | roughly 10 seconds later and of course not if you reset your system time |
661 | again). |
1010 | again). |
662 | .PP |
1011 | .PP |
663 | They can also be used to implement vastly more complex timers, such as |
1012 | They can also be used to implement vastly more complex timers, such as |
… | |
… | |
744 | .IX Item "ev_periodic_again (loop, ev_periodic *)" |
1093 | .IX Item "ev_periodic_again (loop, ev_periodic *)" |
745 | Simply stops and restarts the periodic watcher again. This is only useful |
1094 | Simply stops and restarts the periodic watcher again. This is only useful |
746 | when you changed some parameters or the reschedule callback would return |
1095 | when you changed some parameters or the reschedule callback would return |
747 | a different time than the last time it was called (e.g. in a crond like |
1096 | a different time than the last time it was called (e.g. in a crond like |
748 | program when the crontabs have changed). |
1097 | program when the crontabs have changed). |
|
|
1098 | .PP |
|
|
1099 | Example: call a callback every hour, or, more precisely, whenever the |
|
|
1100 | system clock is divisible by 3600. The callback invocation times have |
|
|
1101 | potentially a lot of jittering, but good long-term stability. |
|
|
1102 | .PP |
|
|
1103 | .Vb 5 |
|
|
1104 | \& static void |
|
|
1105 | \& clock_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
|
|
1106 | \& { |
|
|
1107 | \& ... its now a full hour (UTC, or TAI or whatever your clock follows) |
|
|
1108 | \& } |
|
|
1109 | .Ve |
|
|
1110 | .PP |
|
|
1111 | .Vb 3 |
|
|
1112 | \& struct ev_periodic hourly_tick; |
|
|
1113 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); |
|
|
1114 | \& ev_periodic_start (loop, &hourly_tick); |
|
|
1115 | .Ve |
|
|
1116 | .PP |
|
|
1117 | Example: the same as above, but use a reschedule callback to do it: |
|
|
1118 | .PP |
|
|
1119 | .Vb 1 |
|
|
1120 | \& #include <math.h> |
|
|
1121 | .Ve |
|
|
1122 | .PP |
|
|
1123 | .Vb 5 |
|
|
1124 | \& static ev_tstamp |
|
|
1125 | \& my_scheduler_cb (struct ev_periodic *w, ev_tstamp now) |
|
|
1126 | \& { |
|
|
1127 | \& return fmod (now, 3600.) + 3600.; |
|
|
1128 | \& } |
|
|
1129 | .Ve |
|
|
1130 | .PP |
|
|
1131 | .Vb 1 |
|
|
1132 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); |
|
|
1133 | .Ve |
|
|
1134 | .PP |
|
|
1135 | Example: call a callback every hour, starting now: |
|
|
1136 | .PP |
|
|
1137 | .Vb 4 |
|
|
1138 | \& struct ev_periodic hourly_tick; |
|
|
1139 | \& ev_periodic_init (&hourly_tick, clock_cb, |
|
|
1140 | \& fmod (ev_now (loop), 3600.), 3600., 0); |
|
|
1141 | \& ev_periodic_start (loop, &hourly_tick); |
|
|
1142 | .Ve |
749 | .ie n .Sh """ev_signal"" \- signal me when a signal gets signalled" |
1143 | .ie n .Sh """ev_signal"" \- signal me when a signal gets signalled!" |
750 | .el .Sh "\f(CWev_signal\fP \- signal me when a signal gets signalled" |
1144 | .el .Sh "\f(CWev_signal\fP \- signal me when a signal gets signalled!" |
751 | .IX Subsection "ev_signal - signal me when a signal gets signalled" |
1145 | .IX Subsection "ev_signal - signal me when a signal gets signalled!" |
752 | Signal watchers will trigger an event when the process receives a specific |
1146 | Signal watchers will trigger an event when the process receives a specific |
753 | signal one or more times. Even though signals are very asynchronous, libev |
1147 | signal one or more times. Even though signals are very asynchronous, libev |
754 | will try it's best to deliver signals synchronously, i.e. as part of the |
1148 | will try it's best to deliver signals synchronously, i.e. as part of the |
755 | normal event processing, like any other event. |
1149 | normal event processing, like any other event. |
756 | .PP |
1150 | .PP |
… | |
… | |
766 | .IP "ev_signal_set (ev_signal *, int signum)" 4 |
1160 | .IP "ev_signal_set (ev_signal *, int signum)" 4 |
767 | .IX Item "ev_signal_set (ev_signal *, int signum)" |
1161 | .IX Item "ev_signal_set (ev_signal *, int signum)" |
768 | .PD |
1162 | .PD |
769 | Configures the watcher to trigger on the given signal number (usually one |
1163 | Configures the watcher to trigger on the given signal number (usually one |
770 | of the \f(CW\*(C`SIGxxx\*(C'\fR constants). |
1164 | of the \f(CW\*(C`SIGxxx\*(C'\fR constants). |
771 | .ie n .Sh """ev_child"" \- wait for pid status changes" |
1165 | .ie n .Sh """ev_child"" \- watch out for process status changes" |
772 | .el .Sh "\f(CWev_child\fP \- wait for pid status changes" |
1166 | .el .Sh "\f(CWev_child\fP \- watch out for process status changes" |
773 | .IX Subsection "ev_child - wait for pid status changes" |
1167 | .IX Subsection "ev_child - watch out for process status changes" |
774 | Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to |
1168 | Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to |
775 | some child status changes (most typically when a child of yours dies). |
1169 | some child status changes (most typically when a child of yours dies). |
776 | .IP "ev_child_init (ev_child *, callback, int pid)" 4 |
1170 | .IP "ev_child_init (ev_child *, callback, int pid)" 4 |
777 | .IX Item "ev_child_init (ev_child *, callback, int pid)" |
1171 | .IX Item "ev_child_init (ev_child *, callback, int pid)" |
778 | .PD 0 |
1172 | .PD 0 |
… | |
… | |
783 | \&\fIany\fR process if \f(CW\*(C`pid\*(C'\fR is specified as \f(CW0\fR). The callback can look |
1177 | \&\fIany\fR process if \f(CW\*(C`pid\*(C'\fR is specified as \f(CW0\fR). The callback can look |
784 | at the \f(CW\*(C`rstatus\*(C'\fR member of the \f(CW\*(C`ev_child\*(C'\fR watcher structure to see |
1178 | at the \f(CW\*(C`rstatus\*(C'\fR member of the \f(CW\*(C`ev_child\*(C'\fR watcher structure to see |
785 | the status word (use the macros from \f(CW\*(C`sys/wait.h\*(C'\fR and see your systems |
1179 | the status word (use the macros from \f(CW\*(C`sys/wait.h\*(C'\fR and see your systems |
786 | \&\f(CW\*(C`waitpid\*(C'\fR documentation). The \f(CW\*(C`rpid\*(C'\fR member contains the pid of the |
1180 | \&\f(CW\*(C`waitpid\*(C'\fR documentation). The \f(CW\*(C`rpid\*(C'\fR member contains the pid of the |
787 | process causing the status change. |
1181 | process causing the status change. |
|
|
1182 | .PP |
|
|
1183 | Example: try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0. |
|
|
1184 | .PP |
|
|
1185 | .Vb 5 |
|
|
1186 | \& static void |
|
|
1187 | \& sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
|
|
1188 | \& { |
|
|
1189 | \& ev_unloop (loop, EVUNLOOP_ALL); |
|
|
1190 | \& } |
|
|
1191 | .Ve |
|
|
1192 | .PP |
|
|
1193 | .Vb 3 |
|
|
1194 | \& struct ev_signal signal_watcher; |
|
|
1195 | \& ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
|
|
1196 | \& ev_signal_start (loop, &sigint_cb); |
|
|
1197 | .Ve |
788 | .ie n .Sh """ev_idle"" \- when you've got nothing better to do" |
1198 | .ie n .Sh """ev_idle"" \- when you've got nothing better to do..." |
789 | .el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do" |
1199 | .el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do..." |
790 | .IX Subsection "ev_idle - when you've got nothing better to do" |
1200 | .IX Subsection "ev_idle - when you've got nothing better to do..." |
791 | Idle watchers trigger events when there are no other events are pending |
1201 | Idle watchers trigger events when there are no other events are pending |
792 | (prepare, check and other idle watchers do not count). That is, as long |
1202 | (prepare, check and other idle watchers do not count). That is, as long |
793 | as your process is busy handling sockets or timeouts (or even signals, |
1203 | as your process is busy handling sockets or timeouts (or even signals, |
794 | imagine) it will not be triggered. But when your process is idle all idle |
1204 | imagine) it will not be triggered. But when your process is idle all idle |
795 | watchers are being called again and again, once per event loop iteration \- |
1205 | watchers are being called again and again, once per event loop iteration \- |
… | |
… | |
806 | .IP "ev_idle_init (ev_signal *, callback)" 4 |
1216 | .IP "ev_idle_init (ev_signal *, callback)" 4 |
807 | .IX Item "ev_idle_init (ev_signal *, callback)" |
1217 | .IX Item "ev_idle_init (ev_signal *, callback)" |
808 | Initialises and configures the idle watcher \- it has no parameters of any |
1218 | Initialises and configures the idle watcher \- it has no parameters of any |
809 | kind. There is a \f(CW\*(C`ev_idle_set\*(C'\fR macro, but using it is utterly pointless, |
1219 | kind. There is a \f(CW\*(C`ev_idle_set\*(C'\fR macro, but using it is utterly pointless, |
810 | believe me. |
1220 | believe me. |
|
|
1221 | .PP |
|
|
1222 | Example: dynamically allocate an \f(CW\*(C`ev_idle\*(C'\fR, start it, and in the |
|
|
1223 | callback, free it. Alos, use no error checking, as usual. |
|
|
1224 | .PP |
|
|
1225 | .Vb 7 |
|
|
1226 | \& static void |
|
|
1227 | \& idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
|
|
1228 | \& { |
|
|
1229 | \& free (w); |
|
|
1230 | \& // now do something you wanted to do when the program has |
|
|
1231 | \& // no longer asnything immediate to do. |
|
|
1232 | \& } |
|
|
1233 | .Ve |
|
|
1234 | .PP |
|
|
1235 | .Vb 3 |
|
|
1236 | \& struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle)); |
|
|
1237 | \& ev_idle_init (idle_watcher, idle_cb); |
|
|
1238 | \& ev_idle_start (loop, idle_cb); |
|
|
1239 | .Ve |
811 | .ie n .Sh """ev_prepare""\fP and \f(CW""ev_check"" \- customise your event loop" |
1240 | .ie n .Sh """ev_prepare""\fP and \f(CW""ev_check"" \- customise your event loop!" |
812 | .el .Sh "\f(CWev_prepare\fP and \f(CWev_check\fP \- customise your event loop" |
1241 | .el .Sh "\f(CWev_prepare\fP and \f(CWev_check\fP \- customise your event loop!" |
813 | .IX Subsection "ev_prepare and ev_check - customise your event loop" |
1242 | .IX Subsection "ev_prepare and ev_check - customise your event loop!" |
814 | Prepare and check watchers are usually (but not always) used in tandem: |
1243 | Prepare and check watchers are usually (but not always) used in tandem: |
815 | prepare watchers get invoked before the process blocks and check watchers |
1244 | prepare watchers get invoked before the process blocks and check watchers |
816 | afterwards. |
1245 | afterwards. |
817 | .PP |
1246 | .PP |
818 | Their main purpose is to integrate other event mechanisms into libev. This |
1247 | Their main purpose is to integrate other event mechanisms into libev and |
819 | could be used, for example, to track variable changes, implement your own |
1248 | their use is somewhat advanced. This could be used, for example, to track |
820 | watchers, integrate net-snmp or a coroutine library and lots more. |
1249 | variable changes, implement your own watchers, integrate net-snmp or a |
|
|
1250 | coroutine library and lots more. |
821 | .PP |
1251 | .PP |
822 | This is done by examining in each prepare call which file descriptors need |
1252 | This is done by examining in each prepare call which file descriptors need |
823 | to be watched by the other library, registering \f(CW\*(C`ev_io\*(C'\fR watchers for |
1253 | to be watched by the other library, registering \f(CW\*(C`ev_io\*(C'\fR watchers for |
824 | them and starting an \f(CW\*(C`ev_timer\*(C'\fR watcher for any timeouts (many libraries |
1254 | them and starting an \f(CW\*(C`ev_timer\*(C'\fR watcher for any timeouts (many libraries |
825 | provide just this functionality). Then, in the check watcher you check for |
1255 | provide just this functionality). Then, in the check watcher you check for |
… | |
… | |
843 | .IX Item "ev_check_init (ev_check *, callback)" |
1273 | .IX Item "ev_check_init (ev_check *, callback)" |
844 | .PD |
1274 | .PD |
845 | Initialises and configures the prepare or check watcher \- they have no |
1275 | Initialises and configures the prepare or check watcher \- they have no |
846 | parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR |
1276 | parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR |
847 | macros, but using them is utterly, utterly and completely pointless. |
1277 | macros, but using them is utterly, utterly and completely pointless. |
|
|
1278 | .PP |
|
|
1279 | Example: *TODO*. |
|
|
1280 | .ie n .Sh """ev_embed"" \- when one backend isn't enough..." |
|
|
1281 | .el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..." |
|
|
1282 | .IX Subsection "ev_embed - when one backend isn't enough..." |
|
|
1283 | This is a rather advanced watcher type that lets you embed one event loop |
|
|
1284 | into another (currently only \f(CW\*(C`ev_io\*(C'\fR events are supported in the embedded |
|
|
1285 | loop, other types of watchers might be handled in a delayed or incorrect |
|
|
1286 | fashion and must not be used). |
|
|
1287 | .PP |
|
|
1288 | There are primarily two reasons you would want that: work around bugs and |
|
|
1289 | prioritise I/O. |
|
|
1290 | .PP |
|
|
1291 | As an example for a bug workaround, the kqueue backend might only support |
|
|
1292 | sockets on some platform, so it is unusable as generic backend, but you |
|
|
1293 | still want to make use of it because you have many sockets and it scales |
|
|
1294 | so nicely. In this case, you would create a kqueue-based loop and embed it |
|
|
1295 | into your default loop (which might use e.g. poll). Overall operation will |
|
|
1296 | be a bit slower because first libev has to poll and then call kevent, but |
|
|
1297 | at least you can use both at what they are best. |
|
|
1298 | .PP |
|
|
1299 | As for prioritising I/O: rarely you have the case where some fds have |
|
|
1300 | to be watched and handled very quickly (with low latency), and even |
|
|
1301 | priorities and idle watchers might have too much overhead. In this case |
|
|
1302 | you would put all the high priority stuff in one loop and all the rest in |
|
|
1303 | a second one, and embed the second one in the first. |
|
|
1304 | .PP |
|
|
1305 | As long as the watcher is active, the callback will be invoked every time |
|
|
1306 | there might be events pending in the embedded loop. The callback must then |
|
|
1307 | call \f(CW\*(C`ev_embed_sweep (mainloop, watcher)\*(C'\fR to make a single sweep and invoke |
|
|
1308 | their callbacks (you could also start an idle watcher to give the embedded |
|
|
1309 | loop strictly lower priority for example). You can also set the callback |
|
|
1310 | to \f(CW0\fR, in which case the embed watcher will automatically execute the |
|
|
1311 | embedded loop sweep. |
|
|
1312 | .PP |
|
|
1313 | As long as the watcher is started it will automatically handle events. The |
|
|
1314 | callback will be invoked whenever some events have been handled. You can |
|
|
1315 | set the callback to \f(CW0\fR to avoid having to specify one if you are not |
|
|
1316 | interested in that. |
|
|
1317 | .PP |
|
|
1318 | Also, there have not currently been made special provisions for forking: |
|
|
1319 | when you fork, you not only have to call \f(CW\*(C`ev_loop_fork\*(C'\fR on both loops, |
|
|
1320 | but you will also have to stop and restart any \f(CW\*(C`ev_embed\*(C'\fR watchers |
|
|
1321 | yourself. |
|
|
1322 | .PP |
|
|
1323 | Unfortunately, not all backends are embeddable, only the ones returned by |
|
|
1324 | \&\f(CW\*(C`ev_embeddable_backends\*(C'\fR are, which, unfortunately, does not include any |
|
|
1325 | portable one. |
|
|
1326 | .PP |
|
|
1327 | So when you want to use this feature you will always have to be prepared |
|
|
1328 | that you cannot get an embeddable loop. The recommended way to get around |
|
|
1329 | this is to have a separate variables for your embeddable loop, try to |
|
|
1330 | create it, and if that fails, use the normal loop for everything: |
|
|
1331 | .PP |
|
|
1332 | .Vb 3 |
|
|
1333 | \& struct ev_loop *loop_hi = ev_default_init (0); |
|
|
1334 | \& struct ev_loop *loop_lo = 0; |
|
|
1335 | \& struct ev_embed embed; |
|
|
1336 | .Ve |
|
|
1337 | .PP |
|
|
1338 | .Vb 5 |
|
|
1339 | \& // see if there is a chance of getting one that works |
|
|
1340 | \& // (remember that a flags value of 0 means autodetection) |
|
|
1341 | \& loop_lo = ev_embeddable_backends () & ev_recommended_backends () |
|
|
1342 | \& ? ev_loop_new (ev_embeddable_backends () & ev_recommended_backends ()) |
|
|
1343 | \& : 0; |
|
|
1344 | .Ve |
|
|
1345 | .PP |
|
|
1346 | .Vb 8 |
|
|
1347 | \& // if we got one, then embed it, otherwise default to loop_hi |
|
|
1348 | \& if (loop_lo) |
|
|
1349 | \& { |
|
|
1350 | \& ev_embed_init (&embed, 0, loop_lo); |
|
|
1351 | \& ev_embed_start (loop_hi, &embed); |
|
|
1352 | \& } |
|
|
1353 | \& else |
|
|
1354 | \& loop_lo = loop_hi; |
|
|
1355 | .Ve |
|
|
1356 | .IP "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
|
|
1357 | .IX Item "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" |
|
|
1358 | .PD 0 |
|
|
1359 | .IP "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
|
|
1360 | .IX Item "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" |
|
|
1361 | .PD |
|
|
1362 | Configures the watcher to embed the given loop, which must be |
|
|
1363 | embeddable. If the callback is \f(CW0\fR, then \f(CW\*(C`ev_embed_sweep\*(C'\fR will be |
|
|
1364 | invoked automatically, otherwise it is the responsibility of the callback |
|
|
1365 | to invoke it (it will continue to be called until the sweep has been done, |
|
|
1366 | if you do not want thta, you need to temporarily stop the embed watcher). |
|
|
1367 | .IP "ev_embed_sweep (loop, ev_embed *)" 4 |
|
|
1368 | .IX Item "ev_embed_sweep (loop, ev_embed *)" |
|
|
1369 | Make a single, non-blocking sweep over the embedded loop. This works |
|
|
1370 | similarly to \f(CW\*(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\*(C'\fR, but in the most |
|
|
1371 | apropriate way for embedded loops. |
848 | .SH "OTHER FUNCTIONS" |
1372 | .SH "OTHER FUNCTIONS" |
849 | .IX Header "OTHER FUNCTIONS" |
1373 | .IX Header "OTHER FUNCTIONS" |
850 | There are some other functions of possible interest. Described. Here. Now. |
1374 | There are some other functions of possible interest. Described. Here. Now. |
851 | .IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4 |
1375 | .IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4 |
852 | .IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" |
1376 | .IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" |
… | |
… | |
881 | .Ve |
1405 | .Ve |
882 | .Sp |
1406 | .Sp |
883 | .Vb 1 |
1407 | .Vb 1 |
884 | \& ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0); |
1408 | \& ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0); |
885 | .Ve |
1409 | .Ve |
886 | .IP "ev_feed_event (loop, watcher, int events)" 4 |
1410 | .IP "ev_feed_event (ev_loop *, watcher *, int revents)" 4 |
887 | .IX Item "ev_feed_event (loop, watcher, int events)" |
1411 | .IX Item "ev_feed_event (ev_loop *, watcher *, int revents)" |
888 | Feeds the given event set into the event loop, as if the specified event |
1412 | Feeds the given event set into the event loop, as if the specified event |
889 | had happened for the specified watcher (which must be a pointer to an |
1413 | had happened for the specified watcher (which must be a pointer to an |
890 | initialised but not necessarily started event watcher). |
1414 | initialised but not necessarily started event watcher). |
891 | .IP "ev_feed_fd_event (loop, int fd, int revents)" 4 |
1415 | .IP "ev_feed_fd_event (ev_loop *, int fd, int revents)" 4 |
892 | .IX Item "ev_feed_fd_event (loop, int fd, int revents)" |
1416 | .IX Item "ev_feed_fd_event (ev_loop *, int fd, int revents)" |
893 | Feed an event on the given fd, as if a file descriptor backend detected |
1417 | Feed an event on the given fd, as if a file descriptor backend detected |
894 | the given events it. |
1418 | the given events it. |
895 | .IP "ev_feed_signal_event (loop, int signum)" 4 |
1419 | .IP "ev_feed_signal_event (ev_loop *loop, int signum)" 4 |
896 | .IX Item "ev_feed_signal_event (loop, int signum)" |
1420 | .IX Item "ev_feed_signal_event (ev_loop *loop, int signum)" |
897 | Feed an event as if the given signal occured (loop must be the default loop!). |
1421 | Feed an event as if the given signal occured (\f(CW\*(C`loop\*(C'\fR must be the default |
|
|
1422 | loop!). |
898 | .SH "LIBEVENT EMULATION" |
1423 | .SH "LIBEVENT EMULATION" |
899 | .IX Header "LIBEVENT EMULATION" |
1424 | .IX Header "LIBEVENT EMULATION" |
900 | Libev offers a compatibility emulation layer for libevent. It cannot |
1425 | Libev offers a compatibility emulation layer for libevent. It cannot |
901 | emulate the internals of libevent, so here are some usage hints: |
1426 | emulate the internals of libevent, so here are some usage hints: |
902 | .IP "* Use it by including <event.h>, as usual." 4 |
1427 | .IP "* Use it by including <event.h>, as usual." 4 |
… | |
… | |
913 | .IP "* The libev emulation is \fInot\fR \s-1ABI\s0 compatible to libevent, you need to use the libev header file and library." 4 |
1438 | .IP "* The libev emulation is \fInot\fR \s-1ABI\s0 compatible to libevent, you need to use the libev header file and library." 4 |
914 | .IX Item "The libev emulation is not ABI compatible to libevent, you need to use the libev header file and library." |
1439 | .IX Item "The libev emulation is not ABI compatible to libevent, you need to use the libev header file and library." |
915 | .PD |
1440 | .PD |
916 | .SH "\*(C+ SUPPORT" |
1441 | .SH "\*(C+ SUPPORT" |
917 | .IX Header " SUPPORT" |
1442 | .IX Header " SUPPORT" |
918 | \&\s-1TBD\s0. |
1443 | Libev comes with some simplistic wrapper classes for \*(C+ that mainly allow |
|
|
1444 | you to use some convinience methods to start/stop watchers and also change |
|
|
1445 | the callback model to a model using method callbacks on objects. |
|
|
1446 | .PP |
|
|
1447 | To use it, |
|
|
1448 | .PP |
|
|
1449 | .Vb 1 |
|
|
1450 | \& #include <ev++.h> |
|
|
1451 | .Ve |
|
|
1452 | .PP |
|
|
1453 | (it is not installed by default). This automatically includes \fIev.h\fR |
|
|
1454 | and puts all of its definitions (many of them macros) into the global |
|
|
1455 | namespace. All \*(C+ specific things are put into the \f(CW\*(C`ev\*(C'\fR namespace. |
|
|
1456 | .PP |
|
|
1457 | It should support all the same embedding options as \fIev.h\fR, most notably |
|
|
1458 | \&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. |
|
|
1459 | .PP |
|
|
1460 | Here is a list of things available in the \f(CW\*(C`ev\*(C'\fR namespace: |
|
|
1461 | .ie n .IP """ev::READ""\fR, \f(CW""ev::WRITE"" etc." 4 |
|
|
1462 | .el .IP "\f(CWev::READ\fR, \f(CWev::WRITE\fR etc." 4 |
|
|
1463 | .IX Item "ev::READ, ev::WRITE etc." |
|
|
1464 | These are just enum values with the same values as the \f(CW\*(C`EV_READ\*(C'\fR etc. |
|
|
1465 | macros from \fIev.h\fR. |
|
|
1466 | .ie n .IP """ev::tstamp""\fR, \f(CW""ev::now""" 4 |
|
|
1467 | .el .IP "\f(CWev::tstamp\fR, \f(CWev::now\fR" 4 |
|
|
1468 | .IX Item "ev::tstamp, ev::now" |
|
|
1469 | Aliases to the same types/functions as with the \f(CW\*(C`ev_\*(C'\fR prefix. |
|
|
1470 | .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 |
|
|
1471 | .el .IP "\f(CWev::io\fR, \f(CWev::timer\fR, \f(CWev::periodic\fR, \f(CWev::idle\fR, \f(CWev::sig\fR etc." 4 |
|
|
1472 | .IX Item "ev::io, ev::timer, ev::periodic, ev::idle, ev::sig etc." |
|
|
1473 | For each \f(CW\*(C`ev_TYPE\*(C'\fR watcher in \fIev.h\fR there is a corresponding class of |
|
|
1474 | the same name in the \f(CW\*(C`ev\*(C'\fR namespace, with the exception of \f(CW\*(C`ev_signal\*(C'\fR |
|
|
1475 | which is called \f(CW\*(C`ev::sig\*(C'\fR to avoid clashes with the \f(CW\*(C`signal\*(C'\fR macro |
|
|
1476 | defines by many implementations. |
|
|
1477 | .Sp |
|
|
1478 | All of those classes have these methods: |
|
|
1479 | .RS 4 |
|
|
1480 | .IP "ev::TYPE::TYPE (object *, object::method *)" 4 |
|
|
1481 | .IX Item "ev::TYPE::TYPE (object *, object::method *)" |
|
|
1482 | .PD 0 |
|
|
1483 | .IP "ev::TYPE::TYPE (object *, object::method *, struct ev_loop *)" 4 |
|
|
1484 | .IX Item "ev::TYPE::TYPE (object *, object::method *, struct ev_loop *)" |
|
|
1485 | .IP "ev::TYPE::~TYPE" 4 |
|
|
1486 | .IX Item "ev::TYPE::~TYPE" |
|
|
1487 | .PD |
|
|
1488 | The constructor takes a pointer to an object and a method pointer to |
|
|
1489 | the event handler callback to call in this class. The constructor calls |
|
|
1490 | \&\f(CW\*(C`ev_init\*(C'\fR for you, which means you have to call the \f(CW\*(C`set\*(C'\fR method |
|
|
1491 | before starting it. If you do not specify a loop then the constructor |
|
|
1492 | automatically associates the default loop with this watcher. |
|
|
1493 | .Sp |
|
|
1494 | The destructor automatically stops the watcher if it is active. |
|
|
1495 | .IP "w\->set (struct ev_loop *)" 4 |
|
|
1496 | .IX Item "w->set (struct ev_loop *)" |
|
|
1497 | Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only |
|
|
1498 | do this when the watcher is inactive (and not pending either). |
|
|
1499 | .IP "w\->set ([args])" 4 |
|
|
1500 | .IX Item "w->set ([args])" |
|
|
1501 | Basically the same as \f(CW\*(C`ev_TYPE_set\*(C'\fR, with the same args. Must be |
|
|
1502 | called at least once. Unlike the C counterpart, an active watcher gets |
|
|
1503 | automatically stopped and restarted. |
|
|
1504 | .IP "w\->start ()" 4 |
|
|
1505 | .IX Item "w->start ()" |
|
|
1506 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument as the |
|
|
1507 | constructor already takes the loop. |
|
|
1508 | .IP "w\->stop ()" 4 |
|
|
1509 | .IX Item "w->stop ()" |
|
|
1510 | Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument. |
|
|
1511 | .ie n .IP "w\->again () ""ev::timer""\fR, \f(CW""ev::periodic"" only" 4 |
|
|
1512 | .el .IP "w\->again () \f(CWev::timer\fR, \f(CWev::periodic\fR only" 4 |
|
|
1513 | .IX Item "w->again () ev::timer, ev::periodic only" |
|
|
1514 | For \f(CW\*(C`ev::timer\*(C'\fR and \f(CW\*(C`ev::periodic\*(C'\fR, this invokes the corresponding |
|
|
1515 | \&\f(CW\*(C`ev_TYPE_again\*(C'\fR function. |
|
|
1516 | .ie n .IP "w\->sweep () ""ev::embed"" only" 4 |
|
|
1517 | .el .IP "w\->sweep () \f(CWev::embed\fR only" 4 |
|
|
1518 | .IX Item "w->sweep () ev::embed only" |
|
|
1519 | Invokes \f(CW\*(C`ev_embed_sweep\*(C'\fR. |
|
|
1520 | .RE |
|
|
1521 | .RS 4 |
|
|
1522 | .RE |
|
|
1523 | .PP |
|
|
1524 | Example: Define a class with an \s-1IO\s0 and idle watcher, start one of them in |
|
|
1525 | the constructor. |
|
|
1526 | .PP |
|
|
1527 | .Vb 4 |
|
|
1528 | \& class myclass |
|
|
1529 | \& { |
|
|
1530 | \& ev_io io; void io_cb (ev::io &w, int revents); |
|
|
1531 | \& ev_idle idle void idle_cb (ev::idle &w, int revents); |
|
|
1532 | .Ve |
|
|
1533 | .PP |
|
|
1534 | .Vb 2 |
|
|
1535 | \& myclass (); |
|
|
1536 | \& } |
|
|
1537 | .Ve |
|
|
1538 | .PP |
|
|
1539 | .Vb 6 |
|
|
1540 | \& myclass::myclass (int fd) |
|
|
1541 | \& : io (this, &myclass::io_cb), |
|
|
1542 | \& idle (this, &myclass::idle_cb) |
|
|
1543 | \& { |
|
|
1544 | \& io.start (fd, ev::READ); |
|
|
1545 | \& } |
|
|
1546 | .Ve |
|
|
1547 | .SH "EMBEDDING" |
|
|
1548 | .IX Header "EMBEDDING" |
|
|
1549 | Libev can (and often is) directly embedded into host |
|
|
1550 | applications. Examples of applications that embed it include the Deliantra |
|
|
1551 | Game Server, the \s-1EV\s0 perl module, the \s-1GNU\s0 Virtual Private Ethernet (gvpe) |
|
|
1552 | and rxvt\-unicode. |
|
|
1553 | .PP |
|
|
1554 | The goal is to enable you to just copy the neecssary files into your |
|
|
1555 | source directory without having to change even a single line in them, so |
|
|
1556 | you can easily upgrade by simply copying (or having a checked-out copy of |
|
|
1557 | libev somewhere in your source tree). |
|
|
1558 | .Sh "\s-1FILESETS\s0" |
|
|
1559 | .IX Subsection "FILESETS" |
|
|
1560 | Depending on what features you need you need to include one or more sets of files |
|
|
1561 | in your app. |
|
|
1562 | .PP |
|
|
1563 | \fI\s-1CORE\s0 \s-1EVENT\s0 \s-1LOOP\s0\fR |
|
|
1564 | .IX Subsection "CORE EVENT LOOP" |
|
|
1565 | .PP |
|
|
1566 | To include only the libev core (all the \f(CW\*(C`ev_*\*(C'\fR functions), with manual |
|
|
1567 | configuration (no autoconf): |
|
|
1568 | .PP |
|
|
1569 | .Vb 2 |
|
|
1570 | \& #define EV_STANDALONE 1 |
|
|
1571 | \& #include "ev.c" |
|
|
1572 | .Ve |
|
|
1573 | .PP |
|
|
1574 | This will automatically include \fIev.h\fR, too, and should be done in a |
|
|
1575 | single C source file only to provide the function implementations. To use |
|
|
1576 | it, do the same for \fIev.h\fR in all files wishing to use this \s-1API\s0 (best |
|
|
1577 | done by writing a wrapper around \fIev.h\fR that you can include instead and |
|
|
1578 | where you can put other configuration options): |
|
|
1579 | .PP |
|
|
1580 | .Vb 2 |
|
|
1581 | \& #define EV_STANDALONE 1 |
|
|
1582 | \& #include "ev.h" |
|
|
1583 | .Ve |
|
|
1584 | .PP |
|
|
1585 | Both header files and implementation files can be compiled with a \*(C+ |
|
|
1586 | compiler (at least, thats a stated goal, and breakage will be treated |
|
|
1587 | as a bug). |
|
|
1588 | .PP |
|
|
1589 | You need the following files in your source tree, or in a directory |
|
|
1590 | in your include path (e.g. in libev/ when using \-Ilibev): |
|
|
1591 | .PP |
|
|
1592 | .Vb 4 |
|
|
1593 | \& ev.h |
|
|
1594 | \& ev.c |
|
|
1595 | \& ev_vars.h |
|
|
1596 | \& ev_wrap.h |
|
|
1597 | .Ve |
|
|
1598 | .PP |
|
|
1599 | .Vb 1 |
|
|
1600 | \& ev_win32.c required on win32 platforms only |
|
|
1601 | .Ve |
|
|
1602 | .PP |
|
|
1603 | .Vb 5 |
|
|
1604 | \& ev_select.c only when select backend is enabled (which is is by default) |
|
|
1605 | \& ev_poll.c only when poll backend is enabled (disabled by default) |
|
|
1606 | \& ev_epoll.c only when the epoll backend is enabled (disabled by default) |
|
|
1607 | \& ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
|
|
1608 | \& ev_port.c only when the solaris port backend is enabled (disabled by default) |
|
|
1609 | .Ve |
|
|
1610 | .PP |
|
|
1611 | \&\fIev.c\fR includes the backend files directly when enabled, so you only need |
|
|
1612 | to compile a single file. |
|
|
1613 | .PP |
|
|
1614 | \fI\s-1LIBEVENT\s0 \s-1COMPATIBILITY\s0 \s-1API\s0\fR |
|
|
1615 | .IX Subsection "LIBEVENT COMPATIBILITY API" |
|
|
1616 | .PP |
|
|
1617 | To include the libevent compatibility \s-1API\s0, also include: |
|
|
1618 | .PP |
|
|
1619 | .Vb 1 |
|
|
1620 | \& #include "event.c" |
|
|
1621 | .Ve |
|
|
1622 | .PP |
|
|
1623 | in the file including \fIev.c\fR, and: |
|
|
1624 | .PP |
|
|
1625 | .Vb 1 |
|
|
1626 | \& #include "event.h" |
|
|
1627 | .Ve |
|
|
1628 | .PP |
|
|
1629 | in the files that want to use the libevent \s-1API\s0. This also includes \fIev.h\fR. |
|
|
1630 | .PP |
|
|
1631 | You need the following additional files for this: |
|
|
1632 | .PP |
|
|
1633 | .Vb 2 |
|
|
1634 | \& event.h |
|
|
1635 | \& event.c |
|
|
1636 | .Ve |
|
|
1637 | .PP |
|
|
1638 | \fI\s-1AUTOCONF\s0 \s-1SUPPORT\s0\fR |
|
|
1639 | .IX Subsection "AUTOCONF SUPPORT" |
|
|
1640 | .PP |
|
|
1641 | Instead of using \f(CW\*(C`EV_STANDALONE=1\*(C'\fR and providing your config in |
|
|
1642 | whatever way you want, you can also \f(CW\*(C`m4_include([libev.m4])\*(C'\fR in your |
|
|
1643 | \&\fIconfigure.ac\fR and leave \f(CW\*(C`EV_STANDALONE\*(C'\fR off. \fIev.c\fR will then include |
|
|
1644 | \&\fIconfig.h\fR and configure itself accordingly. |
|
|
1645 | .PP |
|
|
1646 | For this of course you need the m4 file: |
|
|
1647 | .PP |
|
|
1648 | .Vb 1 |
|
|
1649 | \& libev.m4 |
|
|
1650 | .Ve |
|
|
1651 | .Sh "\s-1PREPROCESSOR\s0 \s-1SYMBOLS/MACROS\s0" |
|
|
1652 | .IX Subsection "PREPROCESSOR SYMBOLS/MACROS" |
|
|
1653 | Libev can be configured via a variety of preprocessor symbols you have to define |
|
|
1654 | before including any of its files. The default is not to build for multiplicity |
|
|
1655 | and only include the select backend. |
|
|
1656 | .IP "\s-1EV_STANDALONE\s0" 4 |
|
|
1657 | .IX Item "EV_STANDALONE" |
|
|
1658 | Must always be \f(CW1\fR if you do not use autoconf configuration, which |
|
|
1659 | keeps libev from including \fIconfig.h\fR, and it also defines dummy |
|
|
1660 | implementations for some libevent functions (such as logging, which is not |
|
|
1661 | supported). It will also not define any of the structs usually found in |
|
|
1662 | \&\fIevent.h\fR that are not directly supported by the libev core alone. |
|
|
1663 | .IP "\s-1EV_USE_MONOTONIC\s0" 4 |
|
|
1664 | .IX Item "EV_USE_MONOTONIC" |
|
|
1665 | If defined to be \f(CW1\fR, libev will try to detect the availability of the |
|
|
1666 | monotonic clock option at both compiletime and runtime. Otherwise no use |
|
|
1667 | of the monotonic clock option will be attempted. If you enable this, you |
|
|
1668 | usually have to link against librt or something similar. Enabling it when |
|
|
1669 | the functionality isn't available is safe, though, althoguh you have |
|
|
1670 | to make sure you link against any libraries where the \f(CW\*(C`clock_gettime\*(C'\fR |
|
|
1671 | function is hiding in (often \fI\-lrt\fR). |
|
|
1672 | .IP "\s-1EV_USE_REALTIME\s0" 4 |
|
|
1673 | .IX Item "EV_USE_REALTIME" |
|
|
1674 | If defined to be \f(CW1\fR, libev will try to detect the availability of the |
|
|
1675 | realtime clock option at compiletime (and assume its availability at |
|
|
1676 | runtime if successful). Otherwise no use of the realtime clock option will |
|
|
1677 | be attempted. This effectively replaces \f(CW\*(C`gettimeofday\*(C'\fR by \f(CW\*(C`clock_get |
|
|
1678 | (CLOCK_REALTIME, ...)\*(C'\fR and will not normally affect correctness. See tzhe note about libraries |
|
|
1679 | in the description of \f(CW\*(C`EV_USE_MONOTONIC\*(C'\fR, though. |
|
|
1680 | .IP "\s-1EV_USE_SELECT\s0" 4 |
|
|
1681 | .IX Item "EV_USE_SELECT" |
|
|
1682 | If undefined or defined to be \f(CW1\fR, libev will compile in support for the |
|
|
1683 | \&\f(CW\*(C`select\*(C'\fR(2) backend. No attempt at autodetection will be done: if no |
|
|
1684 | other method takes over, select will be it. Otherwise the select backend |
|
|
1685 | will not be compiled in. |
|
|
1686 | .IP "\s-1EV_SELECT_USE_FD_SET\s0" 4 |
|
|
1687 | .IX Item "EV_SELECT_USE_FD_SET" |
|
|
1688 | If defined to \f(CW1\fR, then the select backend will use the system \f(CW\*(C`fd_set\*(C'\fR |
|
|
1689 | structure. This is useful if libev doesn't compile due to a missing |
|
|
1690 | \&\f(CW\*(C`NFDBITS\*(C'\fR or \f(CW\*(C`fd_mask\*(C'\fR definition or it misguesses the bitset layout on |
|
|
1691 | exotic systems. This usually limits the range of file descriptors to some |
|
|
1692 | low limit such as 1024 or might have other limitations (winsocket only |
|
|
1693 | allows 64 sockets). The \f(CW\*(C`FD_SETSIZE\*(C'\fR macro, set before compilation, might |
|
|
1694 | influence the size of the \f(CW\*(C`fd_set\*(C'\fR used. |
|
|
1695 | .IP "\s-1EV_SELECT_IS_WINSOCKET\s0" 4 |
|
|
1696 | .IX Item "EV_SELECT_IS_WINSOCKET" |
|
|
1697 | When defined to \f(CW1\fR, the select backend will assume that |
|
|
1698 | select/socket/connect etc. don't understand file descriptors but |
|
|
1699 | wants osf handles on win32 (this is the case when the select to |
|
|
1700 | be used is the winsock select). This means that it will call |
|
|
1701 | \&\f(CW\*(C`_get_osfhandle\*(C'\fR on the fd to convert it to an \s-1OS\s0 handle. Otherwise, |
|
|
1702 | it is assumed that all these functions actually work on fds, even |
|
|
1703 | on win32. Should not be defined on non\-win32 platforms. |
|
|
1704 | .IP "\s-1EV_USE_POLL\s0" 4 |
|
|
1705 | .IX Item "EV_USE_POLL" |
|
|
1706 | If defined to be \f(CW1\fR, libev will compile in support for the \f(CW\*(C`poll\*(C'\fR(2) |
|
|
1707 | backend. Otherwise it will be enabled on non\-win32 platforms. It |
|
|
1708 | takes precedence over select. |
|
|
1709 | .IP "\s-1EV_USE_EPOLL\s0" 4 |
|
|
1710 | .IX Item "EV_USE_EPOLL" |
|
|
1711 | If defined to be \f(CW1\fR, libev will compile in support for the Linux |
|
|
1712 | \&\f(CW\*(C`epoll\*(C'\fR(7) backend. Its availability will be detected at runtime, |
|
|
1713 | otherwise another method will be used as fallback. This is the |
|
|
1714 | preferred backend for GNU/Linux systems. |
|
|
1715 | .IP "\s-1EV_USE_KQUEUE\s0" 4 |
|
|
1716 | .IX Item "EV_USE_KQUEUE" |
|
|
1717 | If defined to be \f(CW1\fR, libev will compile in support for the \s-1BSD\s0 style |
|
|
1718 | \&\f(CW\*(C`kqueue\*(C'\fR(2) backend. Its actual availability will be detected at runtime, |
|
|
1719 | otherwise another method will be used as fallback. This is the preferred |
|
|
1720 | backend for \s-1BSD\s0 and BSD-like systems, although on most BSDs kqueue only |
|
|
1721 | supports some types of fds correctly (the only platform we found that |
|
|
1722 | supports ptys for example was NetBSD), so kqueue might be compiled in, but |
|
|
1723 | not be used unless explicitly requested. The best way to use it is to find |
|
|
1724 | out whether kqueue supports your type of fd properly and use an embedded |
|
|
1725 | kqueue loop. |
|
|
1726 | .IP "\s-1EV_USE_PORT\s0" 4 |
|
|
1727 | .IX Item "EV_USE_PORT" |
|
|
1728 | If defined to be \f(CW1\fR, libev will compile in support for the Solaris |
|
|
1729 | 10 port style backend. Its availability will be detected at runtime, |
|
|
1730 | otherwise another method will be used as fallback. This is the preferred |
|
|
1731 | backend for Solaris 10 systems. |
|
|
1732 | .IP "\s-1EV_USE_DEVPOLL\s0" 4 |
|
|
1733 | .IX Item "EV_USE_DEVPOLL" |
|
|
1734 | reserved for future expansion, works like the \s-1USE\s0 symbols above. |
|
|
1735 | .IP "\s-1EV_H\s0" 4 |
|
|
1736 | .IX Item "EV_H" |
|
|
1737 | The name of the \fIev.h\fR header file used to include it. The default if |
|
|
1738 | undefined is \f(CW\*(C`<ev.h>\*(C'\fR in \fIevent.h\fR and \f(CW"ev.h"\fR in \fIev.c\fR. This |
|
|
1739 | can be used to virtually rename the \fIev.h\fR header file in case of conflicts. |
|
|
1740 | .IP "\s-1EV_CONFIG_H\s0" 4 |
|
|
1741 | .IX Item "EV_CONFIG_H" |
|
|
1742 | If \f(CW\*(C`EV_STANDALONE\*(C'\fR isn't \f(CW1\fR, this variable can be used to override |
|
|
1743 | \&\fIev.c\fR's idea of where to find the \fIconfig.h\fR file, similarly to |
|
|
1744 | \&\f(CW\*(C`EV_H\*(C'\fR, above. |
|
|
1745 | .IP "\s-1EV_EVENT_H\s0" 4 |
|
|
1746 | .IX Item "EV_EVENT_H" |
|
|
1747 | Similarly to \f(CW\*(C`EV_H\*(C'\fR, this macro can be used to override \fIevent.c\fR's idea |
|
|
1748 | of how the \fIevent.h\fR header can be found. |
|
|
1749 | .IP "\s-1EV_PROTOTYPES\s0" 4 |
|
|
1750 | .IX Item "EV_PROTOTYPES" |
|
|
1751 | If defined to be \f(CW0\fR, then \fIev.h\fR will not define any function |
|
|
1752 | prototypes, but still define all the structs and other symbols. This is |
|
|
1753 | occasionally useful if you want to provide your own wrapper functions |
|
|
1754 | around libev functions. |
|
|
1755 | .IP "\s-1EV_MULTIPLICITY\s0" 4 |
|
|
1756 | .IX Item "EV_MULTIPLICITY" |
|
|
1757 | If undefined or defined to \f(CW1\fR, then all event-loop-specific functions |
|
|
1758 | will have the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument, and you can create |
|
|
1759 | additional independent event loops. Otherwise there will be no support |
|
|
1760 | for multiple event loops and there is no first event loop pointer |
|
|
1761 | argument. Instead, all functions act on the single default loop. |
|
|
1762 | .IP "\s-1EV_PERIODICS\s0" 4 |
|
|
1763 | .IX Item "EV_PERIODICS" |
|
|
1764 | If undefined or defined to be \f(CW1\fR, then periodic timers are supported, |
|
|
1765 | otherwise not. This saves a few kb of code. |
|
|
1766 | .IP "\s-1EV_COMMON\s0" 4 |
|
|
1767 | .IX Item "EV_COMMON" |
|
|
1768 | By default, all watchers have a \f(CW\*(C`void *data\*(C'\fR member. By redefining |
|
|
1769 | this macro to a something else you can include more and other types of |
|
|
1770 | members. You have to define it each time you include one of the files, |
|
|
1771 | though, and it must be identical each time. |
|
|
1772 | .Sp |
|
|
1773 | For example, the perl \s-1EV\s0 module uses something like this: |
|
|
1774 | .Sp |
|
|
1775 | .Vb 3 |
|
|
1776 | \& #define EV_COMMON \e |
|
|
1777 | \& SV *self; /* contains this struct */ \e |
|
|
1778 | \& SV *cb_sv, *fh /* note no trailing ";" */ |
|
|
1779 | .Ve |
|
|
1780 | .IP "\s-1EV_CB_DECLARE\s0(type)" 4 |
|
|
1781 | .IX Item "EV_CB_DECLARE(type)" |
|
|
1782 | .PD 0 |
|
|
1783 | .IP "\s-1EV_CB_INVOKE\s0(watcher,revents)" 4 |
|
|
1784 | .IX Item "EV_CB_INVOKE(watcher,revents)" |
|
|
1785 | .IP "ev_set_cb(ev,cb)" 4 |
|
|
1786 | .IX Item "ev_set_cb(ev,cb)" |
|
|
1787 | .PD |
|
|
1788 | Can be used to change the callback member declaration in each watcher, |
|
|
1789 | and the way callbacks are invoked and set. Must expand to a struct member |
|
|
1790 | definition and a statement, respectively. See the \fIev.v\fR header file for |
|
|
1791 | their default definitions. One possible use for overriding these is to |
|
|
1792 | avoid the ev_loop pointer as first argument in all cases, or to use method |
|
|
1793 | calls instead of plain function calls in \*(C+. |
|
|
1794 | .Sh "\s-1EXAMPLES\s0" |
|
|
1795 | .IX Subsection "EXAMPLES" |
|
|
1796 | For a real-world example of a program the includes libev |
|
|
1797 | verbatim, you can have a look at the \s-1EV\s0 perl module |
|
|
1798 | (<http://software.schmorp.de/pkg/EV.html>). It has the libev files in |
|
|
1799 | the \fIlibev/\fR subdirectory and includes them in the \fI\s-1EV/EVAPI\s0.h\fR (public |
|
|
1800 | interface) and \fI\s-1EV\s0.xs\fR (implementation) files. Only the \fI\s-1EV\s0.xs\fR file |
|
|
1801 | will be compiled. It is pretty complex because it provides its own header |
|
|
1802 | file. |
|
|
1803 | .Sp |
|
|
1804 | The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file |
|
|
1805 | that everybody includes and which overrides some autoconf choices: |
|
|
1806 | .Sp |
|
|
1807 | .Vb 4 |
|
|
1808 | \& #define EV_USE_POLL 0 |
|
|
1809 | \& #define EV_MULTIPLICITY 0 |
|
|
1810 | \& #define EV_PERIODICS 0 |
|
|
1811 | \& #define EV_CONFIG_H <config.h> |
|
|
1812 | .Ve |
|
|
1813 | .Sp |
|
|
1814 | .Vb 1 |
|
|
1815 | \& #include "ev++.h" |
|
|
1816 | .Ve |
|
|
1817 | .Sp |
|
|
1818 | And a \fIev_cpp.C\fR implementation file that contains libev proper and is compiled: |
|
|
1819 | .Sp |
|
|
1820 | .Vb 2 |
|
|
1821 | \& #include "ev_cpp.h" |
|
|
1822 | \& #include "ev.c" |
|
|
1823 | .Ve |
919 | .SH "AUTHOR" |
1824 | .SH "AUTHOR" |
920 | .IX Header "AUTHOR" |
1825 | .IX Header "AUTHOR" |
921 | Marc Lehmann <libev@schmorp.de>. |
1826 | Marc Lehmann <libev@schmorp.de>. |