… | |
… | |
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 "2007-11-24" "perl v5.8.8" "User Contributed Perl Documentation" |
132 | .TH "<STANDARD INPUT>" 1 "2007-12-07" "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 |
138 | \& #include <ev.h> |
138 | \& #include <ev.h> |
139 | .Ve |
139 | .Ve |
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140 | .SH "EXAMPLE PROGRAM" |
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141 | .IX Header "EXAMPLE PROGRAM" |
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142 | .Vb 1 |
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143 | \& #include <ev.h> |
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144 | .Ve |
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145 | .PP |
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146 | .Vb 2 |
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147 | \& ev_io stdin_watcher; |
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148 | \& ev_timer timeout_watcher; |
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149 | .Ve |
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150 | .PP |
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151 | .Vb 8 |
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152 | \& /* called when data readable on stdin */ |
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153 | \& static void |
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154 | \& stdin_cb (EV_P_ struct ev_io *w, int revents) |
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155 | \& { |
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156 | \& /* puts ("stdin ready"); */ |
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157 | \& ev_io_stop (EV_A_ w); /* just a syntax example */ |
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158 | \& ev_unloop (EV_A_ EVUNLOOP_ALL); /* leave all loop calls */ |
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159 | \& } |
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160 | .Ve |
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161 | .PP |
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162 | .Vb 6 |
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163 | \& static void |
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164 | \& timeout_cb (EV_P_ struct ev_timer *w, int revents) |
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165 | \& { |
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166 | \& /* puts ("timeout"); */ |
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167 | \& ev_unloop (EV_A_ EVUNLOOP_ONE); /* leave one loop call */ |
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168 | \& } |
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169 | .Ve |
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170 | .PP |
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171 | .Vb 4 |
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172 | \& int |
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173 | \& main (void) |
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174 | \& { |
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175 | \& struct ev_loop *loop = ev_default_loop (0); |
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176 | .Ve |
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177 | .PP |
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178 | .Vb 3 |
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179 | \& /* initialise an io watcher, then start it */ |
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180 | \& ev_io_init (&stdin_watcher, stdin_cb, /*STDIN_FILENO*/ 0, EV_READ); |
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181 | \& ev_io_start (loop, &stdin_watcher); |
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182 | .Ve |
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183 | .PP |
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184 | .Vb 3 |
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185 | \& /* simple non-repeating 5.5 second timeout */ |
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186 | \& ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.); |
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187 | \& ev_timer_start (loop, &timeout_watcher); |
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188 | .Ve |
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189 | .PP |
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190 | .Vb 2 |
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191 | \& /* loop till timeout or data ready */ |
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192 | \& ev_loop (loop, 0); |
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193 | .Ve |
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194 | .PP |
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195 | .Vb 2 |
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196 | \& return 0; |
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197 | \& } |
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198 | .Ve |
140 | .SH "DESCRIPTION" |
199 | .SH "DESCRIPTION" |
141 | .IX Header "DESCRIPTION" |
200 | .IX Header "DESCRIPTION" |
142 | Libev is an event loop: you register interest in certain events (such as a |
201 | Libev is an event loop: you register interest in certain events (such as a |
143 | file descriptor being readable or a timeout occuring), and it will manage |
202 | file descriptor being readable or a timeout occuring), and it will manage |
144 | these event sources and provide your program with events. |
203 | these event sources and provide your program with events. |
… | |
… | |
151 | watchers\fR, which are relatively small C structures you initialise with the |
210 | watchers\fR, which are relatively small C structures you initialise with the |
152 | details of the event, and then hand it over to libev by \fIstarting\fR the |
211 | details of the event, and then hand it over to libev by \fIstarting\fR the |
153 | watcher. |
212 | watcher. |
154 | .SH "FEATURES" |
213 | .SH "FEATURES" |
155 | .IX Header "FEATURES" |
214 | .IX Header "FEATURES" |
156 | Libev supports select, poll, the linux-specific epoll and the bsd-specific |
215 | Libev supports \f(CW\*(C`select\*(C'\fR, \f(CW\*(C`poll\*(C'\fR, the Linux-specific \f(CW\*(C`epoll\*(C'\fR, the |
157 | kqueue mechanisms for file descriptor events, relative timers, absolute |
216 | BSD-specific \f(CW\*(C`kqueue\*(C'\fR and the Solaris-specific event port mechanisms |
158 | timers with customised rescheduling, signal events, process status change |
217 | for file descriptor events (\f(CW\*(C`ev_io\*(C'\fR), the Linux \f(CW\*(C`inotify\*(C'\fR interface |
159 | events (related to \s-1SIGCHLD\s0), and event watchers dealing with the event |
218 | (for \f(CW\*(C`ev_stat\*(C'\fR), relative timers (\f(CW\*(C`ev_timer\*(C'\fR), absolute timers |
160 | loop mechanism itself (idle, prepare and check watchers). It also is quite |
219 | with customised rescheduling (\f(CW\*(C`ev_periodic\*(C'\fR), synchronous signals |
161 | fast (see this benchmark comparing |
220 | (\f(CW\*(C`ev_signal\*(C'\fR), process status change events (\f(CW\*(C`ev_child\*(C'\fR), and event |
162 | it to libevent for example). |
221 | watchers dealing with the event loop mechanism itself (\f(CW\*(C`ev_idle\*(C'\fR, |
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222 | \&\f(CW\*(C`ev_embed\*(C'\fR, \f(CW\*(C`ev_prepare\*(C'\fR and \f(CW\*(C`ev_check\*(C'\fR watchers) as well as |
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223 | file watchers (\f(CW\*(C`ev_stat\*(C'\fR) and even limited support for fork events |
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224 | (\f(CW\*(C`ev_fork\*(C'\fR). |
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225 | .PP |
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226 | It also is quite fast (see this |
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227 | benchmark comparing it to libevent |
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228 | for example). |
163 | .SH "CONVENTIONS" |
229 | .SH "CONVENTIONS" |
164 | .IX Header "CONVENTIONS" |
230 | .IX Header "CONVENTIONS" |
165 | Libev is very configurable. In this manual the default configuration |
231 | Libev is very configurable. In this manual the default configuration will |
166 | will be described, which supports multiple event loops. For more info |
232 | be described, which supports multiple event loops. For more info about |
167 | about various configuration options please have a look at the file |
233 | various configuration options please have a look at \fB\s-1EMBED\s0\fR section in |
168 | \&\fI\s-1README\s0.embed\fR in the libev distribution. If libev was configured without |
234 | this manual. If libev was configured without support for multiple event |
169 | support for multiple event loops, then all functions taking an initial |
235 | loops, then all functions taking an initial argument of name \f(CW\*(C`loop\*(C'\fR |
170 | argument of name \f(CW\*(C`loop\*(C'\fR (which is always of type \f(CW\*(C`struct ev_loop *\*(C'\fR) |
236 | (which is always of type \f(CW\*(C`struct ev_loop *\*(C'\fR) will not have this argument. |
171 | will not have this argument. |
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172 | .SH "TIME REPRESENTATION" |
237 | .SH "TIME REPRESENTATION" |
173 | .IX Header "TIME REPRESENTATION" |
238 | .IX Header "TIME REPRESENTATION" |
174 | Libev represents time as a single floating point number, representing the |
239 | Libev represents time as a single floating point number, representing the |
175 | (fractional) number of seconds since the (\s-1POSIX\s0) epoch (somewhere near |
240 | (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 |
241 | the beginning of 1970, details are complicated, don't ask). This type is |
… | |
… | |
201 | Usually, it's a good idea to terminate if the major versions mismatch, |
266 | Usually, it's a good idea to terminate if the major versions mismatch, |
202 | as this indicates an incompatible change. Minor versions are usually |
267 | as this indicates an incompatible change. Minor versions are usually |
203 | compatible to older versions, so a larger minor version alone is usually |
268 | compatible to older versions, so a larger minor version alone is usually |
204 | not a problem. |
269 | not a problem. |
205 | .Sp |
270 | .Sp |
206 | Example: make sure we haven't accidentally been linked against the wrong |
271 | Example: Make sure we haven't accidentally been linked against the wrong |
207 | version: |
272 | version. |
208 | .Sp |
273 | .Sp |
209 | .Vb 3 |
274 | .Vb 3 |
210 | \& assert (("libev version mismatch", |
275 | \& assert (("libev version mismatch", |
211 | \& ev_version_major () == EV_VERSION_MAJOR |
276 | \& ev_version_major () == EV_VERSION_MAJOR |
212 | \& && ev_version_minor () >= EV_VERSION_MINOR)); |
277 | \& && ev_version_minor () >= EV_VERSION_MINOR)); |
… | |
… | |
242 | recommended ones. |
307 | recommended ones. |
243 | .Sp |
308 | .Sp |
244 | See the description of \f(CW\*(C`ev_embed\*(C'\fR watchers for more info. |
309 | See the description of \f(CW\*(C`ev_embed\*(C'\fR watchers for more info. |
245 | .IP "ev_set_allocator (void *(*cb)(void *ptr, long size))" 4 |
310 | .IP "ev_set_allocator (void *(*cb)(void *ptr, long size))" 4 |
246 | .IX Item "ev_set_allocator (void *(*cb)(void *ptr, long size))" |
311 | .IX Item "ev_set_allocator (void *(*cb)(void *ptr, long size))" |
247 | Sets the allocation function to use (the prototype is similar to the |
312 | Sets the allocation function to use (the prototype is similar \- the |
248 | realloc C function, the semantics are identical). It is used to allocate |
313 | semantics is identical \- to the realloc C function). It is used to |
249 | and free memory (no surprises here). If it returns zero when memory |
314 | allocate and free memory (no surprises here). If it returns zero when |
250 | needs to be allocated, the library might abort or take some potentially |
315 | memory needs to be allocated, the library might abort or take some |
251 | destructive action. The default is your system realloc function. |
316 | potentially destructive action. The default is your system realloc |
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317 | function. |
252 | .Sp |
318 | .Sp |
253 | You could override this function in high-availability programs to, say, |
319 | You could override this function in high-availability programs to, say, |
254 | free some memory if it cannot allocate memory, to use a special allocator, |
320 | free some memory if it cannot allocate memory, to use a special allocator, |
255 | or even to sleep a while and retry until some memory is available. |
321 | or even to sleep a while and retry until some memory is available. |
256 | .Sp |
322 | .Sp |
257 | Example: replace the libev allocator with one that waits a bit and then |
323 | Example: Replace the libev allocator with one that waits a bit and then |
258 | retries: better than mine). |
324 | retries). |
259 | .Sp |
325 | .Sp |
260 | .Vb 6 |
326 | .Vb 6 |
261 | \& static void * |
327 | \& static void * |
262 | \& persistent_realloc (void *ptr, long size) |
328 | \& persistent_realloc (void *ptr, size_t size) |
263 | \& { |
329 | \& { |
264 | \& for (;;) |
330 | \& for (;;) |
265 | \& { |
331 | \& { |
266 | \& void *newptr = realloc (ptr, size); |
332 | \& void *newptr = realloc (ptr, size); |
267 | .Ve |
333 | .Ve |
… | |
… | |
289 | callback is set, then libev will expect it to remedy the sitution, no |
355 | callback is set, then libev will expect it to remedy the sitution, no |
290 | matter what, when it returns. That is, libev will generally retry the |
356 | matter what, when it returns. That is, libev will generally retry the |
291 | requested operation, or, if the condition doesn't go away, do bad stuff |
357 | requested operation, or, if the condition doesn't go away, do bad stuff |
292 | (such as abort). |
358 | (such as abort). |
293 | .Sp |
359 | .Sp |
294 | Example: do the same thing as libev does internally: |
360 | Example: This is basically the same thing that libev does internally, too. |
295 | .Sp |
361 | .Sp |
296 | .Vb 6 |
362 | .Vb 6 |
297 | \& static void |
363 | \& static void |
298 | \& fatal_error (const char *msg) |
364 | \& fatal_error (const char *msg) |
299 | \& { |
365 | \& { |
… | |
… | |
345 | or setgid) then libev will \fInot\fR look at the environment variable |
411 | or setgid) then libev will \fInot\fR look at the environment variable |
346 | \&\f(CW\*(C`LIBEV_FLAGS\*(C'\fR. Otherwise (the default), this environment variable will |
412 | \&\f(CW\*(C`LIBEV_FLAGS\*(C'\fR. Otherwise (the default), this environment variable will |
347 | override the flags completely if it is found in the environment. This is |
413 | override the flags completely if it is found in the environment. This is |
348 | useful to try out specific backends to test their performance, or to work |
414 | useful to try out specific backends to test their performance, or to work |
349 | around bugs. |
415 | around bugs. |
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416 | .ie n .IP """EVFLAG_FORKCHECK""" 4 |
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417 | .el .IP "\f(CWEVFLAG_FORKCHECK\fR" 4 |
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418 | .IX Item "EVFLAG_FORKCHECK" |
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419 | Instead of calling \f(CW\*(C`ev_default_fork\*(C'\fR or \f(CW\*(C`ev_loop_fork\*(C'\fR manually after |
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420 | a fork, you can also make libev check for a fork in each iteration by |
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421 | enabling this flag. |
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422 | .Sp |
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423 | This works by calling \f(CW\*(C`getpid ()\*(C'\fR on every iteration of the loop, |
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424 | and thus this might slow down your event loop if you do a lot of loop |
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425 | iterations and little real work, but is usually not noticeable (on my |
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426 | Linux system for example, \f(CW\*(C`getpid\*(C'\fR is actually a simple 5\-insn sequence |
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427 | without a syscall and thus \fIvery\fR fast, but my Linux system also has |
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428 | \&\f(CW\*(C`pthread_atfork\*(C'\fR which is even faster). |
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429 | .Sp |
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430 | The big advantage of this flag is that you can forget about fork (and |
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431 | forget about forgetting to tell libev about forking) when you use this |
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432 | flag. |
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433 | .Sp |
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434 | This flag setting cannot be overriden or specified in the \f(CW\*(C`LIBEV_FLAGS\*(C'\fR |
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435 | environment variable. |
350 | .ie n .IP """EVBACKEND_SELECT"" (value 1, portable select backend)" 4 |
436 | .ie n .IP """EVBACKEND_SELECT"" (value 1, portable select backend)" 4 |
351 | .el .IP "\f(CWEVBACKEND_SELECT\fR (value 1, portable select backend)" 4 |
437 | .el .IP "\f(CWEVBACKEND_SELECT\fR (value 1, portable select backend)" 4 |
352 | .IX Item "EVBACKEND_SELECT (value 1, portable select backend)" |
438 | .IX Item "EVBACKEND_SELECT (value 1, portable select backend)" |
353 | This is your standard \fIselect\fR\|(2) backend. Not \fIcompletely\fR standard, as |
439 | This is your standard \fIselect\fR\|(2) backend. Not \fIcompletely\fR standard, as |
354 | libev tries to roll its own fd_set with no limits on the number of fds, |
440 | libev tries to roll its own fd_set with no limits on the number of fds, |
… | |
… | |
448 | Similar to \f(CW\*(C`ev_default_loop\*(C'\fR, but always creates a new event loop that is |
534 | Similar to \f(CW\*(C`ev_default_loop\*(C'\fR, but always creates a new event loop that is |
449 | always distinct from the default loop. Unlike the default loop, it cannot |
535 | always distinct from the default loop. Unlike the default loop, it cannot |
450 | handle signal and child watchers, and attempts to do so will be greeted by |
536 | handle signal and child watchers, and attempts to do so will be greeted by |
451 | undefined behaviour (or a failed assertion if assertions are enabled). |
537 | undefined behaviour (or a failed assertion if assertions are enabled). |
452 | .Sp |
538 | .Sp |
453 | Example: try to create a event loop that uses epoll and nothing else. |
539 | Example: Try to create a event loop that uses epoll and nothing else. |
454 | .Sp |
540 | .Sp |
455 | .Vb 3 |
541 | .Vb 3 |
456 | \& struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
542 | \& struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
457 | \& if (!epoller) |
543 | \& if (!epoller) |
458 | \& fatal ("no epoll found here, maybe it hides under your chair"); |
544 | \& fatal ("no epoll found here, maybe it hides under your chair"); |
… | |
… | |
495 | .IP "ev_loop_fork (loop)" 4 |
581 | .IP "ev_loop_fork (loop)" 4 |
496 | .IX Item "ev_loop_fork (loop)" |
582 | .IX Item "ev_loop_fork (loop)" |
497 | Like \f(CW\*(C`ev_default_fork\*(C'\fR, but acts on an event loop created by |
583 | Like \f(CW\*(C`ev_default_fork\*(C'\fR, but acts on an event loop created by |
498 | \&\f(CW\*(C`ev_loop_new\*(C'\fR. Yes, you have to call this on every allocated event loop |
584 | \&\f(CW\*(C`ev_loop_new\*(C'\fR. Yes, you have to call this on every allocated event loop |
499 | after fork, and how you do this is entirely your own problem. |
585 | after fork, and how you do this is entirely your own problem. |
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586 | .IP "unsigned int ev_loop_count (loop)" 4 |
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587 | .IX Item "unsigned int ev_loop_count (loop)" |
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588 | Returns the count of loop iterations for the loop, which is identical to |
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589 | the number of times libev did poll for new events. It starts at \f(CW0\fR and |
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590 | happily wraps around with enough iterations. |
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591 | .Sp |
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592 | This value can sometimes be useful as a generation counter of sorts (it |
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593 | \&\*(L"ticks\*(R" the number of loop iterations), as it roughly corresponds with |
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594 | \&\f(CW\*(C`ev_prepare\*(C'\fR and \f(CW\*(C`ev_check\*(C'\fR calls. |
500 | .IP "unsigned int ev_backend (loop)" 4 |
595 | .IP "unsigned int ev_backend (loop)" 4 |
501 | .IX Item "unsigned int ev_backend (loop)" |
596 | .IX Item "unsigned int ev_backend (loop)" |
502 | Returns one of the \f(CW\*(C`EVBACKEND_*\*(C'\fR flags indicating the event backend in |
597 | Returns one of the \f(CW\*(C`EVBACKEND_*\*(C'\fR flags indicating the event backend in |
503 | use. |
598 | use. |
504 | .IP "ev_tstamp ev_now (loop)" 4 |
599 | .IP "ev_tstamp ev_now (loop)" 4 |
… | |
… | |
556 | \& be handled here by queueing them when their watcher gets executed. |
651 | \& be handled here by queueing them when their watcher gets executed. |
557 | \& - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
652 | \& - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
558 | \& were used, return, otherwise continue with step *. |
653 | \& were used, return, otherwise continue with step *. |
559 | .Ve |
654 | .Ve |
560 | .Sp |
655 | .Sp |
561 | Example: queue some jobs and then loop until no events are outsanding |
656 | Example: Queue some jobs and then loop until no events are outsanding |
562 | anymore. |
657 | anymore. |
563 | .Sp |
658 | .Sp |
564 | .Vb 4 |
659 | .Vb 4 |
565 | \& ... queue jobs here, make sure they register event watchers as long |
660 | \& ... 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..) |
661 | \& ... as they still have work to do (even an idle watcher will do..) |
… | |
… | |
588 | visible to the libev user and should not keep \f(CW\*(C`ev_loop\*(C'\fR from exiting if |
683 | visible to the libev user and should not keep \f(CW\*(C`ev_loop\*(C'\fR from exiting if |
589 | no event watchers registered by it are active. It is also an excellent |
684 | no event watchers registered by it are active. It is also an excellent |
590 | way to do this for generic recurring timers or from within third-party |
685 | way to do this for generic recurring timers or from within third-party |
591 | libraries. Just remember to \fIunref after start\fR and \fIref before stop\fR. |
686 | libraries. Just remember to \fIunref after start\fR and \fIref before stop\fR. |
592 | .Sp |
687 | .Sp |
593 | Example: create a signal watcher, but keep it from keeping \f(CW\*(C`ev_loop\*(C'\fR |
688 | Example: Create a signal watcher, but keep it from keeping \f(CW\*(C`ev_loop\*(C'\fR |
594 | running when nothing else is active. |
689 | running when nothing else is active. |
595 | .Sp |
690 | .Sp |
596 | .Vb 4 |
691 | .Vb 4 |
597 | \& struct dv_signal exitsig; |
692 | \& struct ev_signal exitsig; |
598 | \& ev_signal_init (&exitsig, sig_cb, SIGINT); |
693 | \& ev_signal_init (&exitsig, sig_cb, SIGINT); |
599 | \& ev_signal_start (myloop, &exitsig); |
694 | \& ev_signal_start (loop, &exitsig); |
600 | \& evf_unref (myloop); |
695 | \& evf_unref (loop); |
601 | .Ve |
696 | .Ve |
602 | .Sp |
697 | .Sp |
603 | Example: for some weird reason, unregister the above signal handler again. |
698 | Example: For some weird reason, unregister the above signal handler again. |
604 | .Sp |
699 | .Sp |
605 | .Vb 2 |
700 | .Vb 2 |
606 | \& ev_ref (myloop); |
701 | \& ev_ref (loop); |
607 | \& ev_signal_stop (myloop, &exitsig); |
702 | \& ev_signal_stop (loop, &exitsig); |
608 | .Ve |
703 | .Ve |
609 | .SH "ANATOMY OF A WATCHER" |
704 | .SH "ANATOMY OF A WATCHER" |
610 | .IX Header "ANATOMY OF A WATCHER" |
705 | .IX Header "ANATOMY OF A WATCHER" |
611 | A watcher is a structure that you create and register to record your |
706 | A watcher is a structure that you create and register to record your |
612 | interest in some event. For instance, if you want to wait for \s-1STDIN\s0 to |
707 | interest in some event. For instance, if you want to wait for \s-1STDIN\s0 to |
… | |
… | |
684 | The signal specified in the \f(CW\*(C`ev_signal\*(C'\fR watcher has been received by a thread. |
779 | The signal specified in the \f(CW\*(C`ev_signal\*(C'\fR watcher has been received by a thread. |
685 | .ie n .IP """EV_CHILD""" 4 |
780 | .ie n .IP """EV_CHILD""" 4 |
686 | .el .IP "\f(CWEV_CHILD\fR" 4 |
781 | .el .IP "\f(CWEV_CHILD\fR" 4 |
687 | .IX Item "EV_CHILD" |
782 | .IX Item "EV_CHILD" |
688 | The pid specified in the \f(CW\*(C`ev_child\*(C'\fR watcher has received a status change. |
783 | The pid specified in the \f(CW\*(C`ev_child\*(C'\fR watcher has received a status change. |
|
|
784 | .ie n .IP """EV_STAT""" 4 |
|
|
785 | .el .IP "\f(CWEV_STAT\fR" 4 |
|
|
786 | .IX Item "EV_STAT" |
|
|
787 | The path specified in the \f(CW\*(C`ev_stat\*(C'\fR watcher changed its attributes somehow. |
689 | .ie n .IP """EV_IDLE""" 4 |
788 | .ie n .IP """EV_IDLE""" 4 |
690 | .el .IP "\f(CWEV_IDLE\fR" 4 |
789 | .el .IP "\f(CWEV_IDLE\fR" 4 |
691 | .IX Item "EV_IDLE" |
790 | .IX Item "EV_IDLE" |
692 | The \f(CW\*(C`ev_idle\*(C'\fR watcher has determined that you have nothing better to do. |
791 | The \f(CW\*(C`ev_idle\*(C'\fR watcher has determined that you have nothing better to do. |
693 | .ie n .IP """EV_PREPARE""" 4 |
792 | .ie n .IP """EV_PREPARE""" 4 |
… | |
… | |
703 | \&\f(CW\*(C`ev_loop\*(C'\fR has gathered them, but before it invokes any callbacks for any |
802 | \&\f(CW\*(C`ev_loop\*(C'\fR has gathered them, but before it invokes any callbacks for any |
704 | received events. Callbacks of both watcher types can start and stop as |
803 | received events. Callbacks of both watcher types can start and stop as |
705 | many watchers as they want, and all of them will be taken into account |
804 | many watchers as they want, and all of them will be taken into account |
706 | (for example, a \f(CW\*(C`ev_prepare\*(C'\fR watcher might start an idle watcher to keep |
805 | (for example, a \f(CW\*(C`ev_prepare\*(C'\fR watcher might start an idle watcher to keep |
707 | \&\f(CW\*(C`ev_loop\*(C'\fR from blocking). |
806 | \&\f(CW\*(C`ev_loop\*(C'\fR from blocking). |
|
|
807 | .ie n .IP """EV_EMBED""" 4 |
|
|
808 | .el .IP "\f(CWEV_EMBED\fR" 4 |
|
|
809 | .IX Item "EV_EMBED" |
|
|
810 | The embedded event loop specified in the \f(CW\*(C`ev_embed\*(C'\fR watcher needs attention. |
|
|
811 | .ie n .IP """EV_FORK""" 4 |
|
|
812 | .el .IP "\f(CWEV_FORK\fR" 4 |
|
|
813 | .IX Item "EV_FORK" |
|
|
814 | The event loop has been resumed in the child process after fork (see |
|
|
815 | \&\f(CW\*(C`ev_fork\*(C'\fR). |
708 | .ie n .IP """EV_ERROR""" 4 |
816 | .ie n .IP """EV_ERROR""" 4 |
709 | .el .IP "\f(CWEV_ERROR\fR" 4 |
817 | .el .IP "\f(CWEV_ERROR\fR" 4 |
710 | .IX Item "EV_ERROR" |
818 | .IX Item "EV_ERROR" |
711 | An unspecified error has occured, the watcher has been stopped. This might |
819 | An unspecified error has occured, the watcher has been stopped. This might |
712 | happen because the watcher could not be properly started because libev |
820 | happen because the watcher could not be properly started because libev |
… | |
… | |
717 | Libev will usually signal a few \*(L"dummy\*(R" events together with an error, |
825 | Libev will usually signal a few \*(L"dummy\*(R" events together with an error, |
718 | for example it might indicate that a fd is readable or writable, and if |
826 | for example it might indicate that a fd is readable or writable, and if |
719 | your callbacks is well-written it can just attempt the operation and cope |
827 | your callbacks is well-written it can just attempt the operation and cope |
720 | with the error from \fIread()\fR or \fIwrite()\fR. This will not work in multithreaded |
828 | with the error from \fIread()\fR or \fIwrite()\fR. This will not work in multithreaded |
721 | programs, though, so beware. |
829 | programs, though, so beware. |
722 | .Sh "\s-1SUMMARY\s0 \s-1OF\s0 \s-1GENERIC\s0 \s-1WATCHER\s0 \s-1FUNCTIONS\s0" |
830 | .Sh "\s-1GENERIC\s0 \s-1WATCHER\s0 \s-1FUNCTIONS\s0" |
723 | .IX Subsection "SUMMARY OF GENERIC WATCHER FUNCTIONS" |
831 | .IX Subsection "GENERIC WATCHER FUNCTIONS" |
724 | In the following description, \f(CW\*(C`TYPE\*(C'\fR stands for the watcher type, |
832 | 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. |
833 | 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 |
834 | .ie n .IP """ev_init"" (ev_TYPE *watcher, callback)" 4 |
727 | .el .IP "\f(CWev_init\fR (ev_TYPE *watcher, callback)" 4 |
835 | .el .IP "\f(CWev_init\fR (ev_TYPE *watcher, callback)" 4 |
728 | .IX Item "ev_init (ev_TYPE *watcher, callback)" |
836 | .IX Item "ev_init (ev_TYPE *watcher, callback)" |
… | |
… | |
734 | which rolls both calls into one. |
842 | which rolls both calls into one. |
735 | .Sp |
843 | .Sp |
736 | You can reinitialise a watcher at any time as long as it has been stopped |
844 | 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. |
845 | (or never started) and there are no pending events outstanding. |
738 | .Sp |
846 | .Sp |
739 | The callbakc is always of type \f(CW\*(C`void (*)(ev_loop *loop, ev_TYPE *watcher, |
847 | The callback is always of type \f(CW\*(C`void (*)(ev_loop *loop, ev_TYPE *watcher, |
740 | int revents)\*(C'\fR. |
848 | int revents)\*(C'\fR. |
741 | .ie n .IP """ev_TYPE_set"" (ev_TYPE *, [args])" 4 |
849 | .ie n .IP """ev_TYPE_set"" (ev_TYPE *, [args])" 4 |
742 | .el .IP "\f(CWev_TYPE_set\fR (ev_TYPE *, [args])" 4 |
850 | .el .IP "\f(CWev_TYPE_set\fR (ev_TYPE *, [args])" 4 |
743 | .IX Item "ev_TYPE_set (ev_TYPE *, [args])" |
851 | .IX Item "ev_TYPE_set (ev_TYPE *, [args])" |
744 | This macro initialises the type-specific parts of a watcher. You need to |
852 | This macro initialises the type-specific parts of a watcher. You need to |
… | |
… | |
779 | Returns a true value iff the watcher is pending, (i.e. it has outstanding |
887 | 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 |
888 | 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 |
889 | 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 |
890 | \&\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). |
891 | libev (e.g. you cnanot \f(CW\*(C`free ()\*(C'\fR it). |
784 | .IP "callback = ev_cb (ev_TYPE *watcher)" 4 |
892 | .IP "callback ev_cb (ev_TYPE *watcher)" 4 |
785 | .IX Item "callback = ev_cb (ev_TYPE *watcher)" |
893 | .IX Item "callback ev_cb (ev_TYPE *watcher)" |
786 | Returns the callback currently set on the watcher. |
894 | Returns the callback currently set on the watcher. |
787 | .IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 |
895 | .IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 |
788 | .IX Item "ev_cb_set (ev_TYPE *watcher, callback)" |
896 | .IX Item "ev_cb_set (ev_TYPE *watcher, callback)" |
789 | Change the callback. You can change the callback at virtually any time |
897 | Change the callback. You can change the callback at virtually any time |
790 | (modulo threads). |
898 | (modulo threads). |
|
|
899 | .IP "ev_set_priority (ev_TYPE *watcher, priority)" 4 |
|
|
900 | .IX Item "ev_set_priority (ev_TYPE *watcher, priority)" |
|
|
901 | .PD 0 |
|
|
902 | .IP "int ev_priority (ev_TYPE *watcher)" 4 |
|
|
903 | .IX Item "int ev_priority (ev_TYPE *watcher)" |
|
|
904 | .PD |
|
|
905 | Set and query the priority of the watcher. The priority is a small |
|
|
906 | integer between \f(CW\*(C`EV_MAXPRI\*(C'\fR (default: \f(CW2\fR) and \f(CW\*(C`EV_MINPRI\*(C'\fR |
|
|
907 | (default: \f(CW\*(C`\-2\*(C'\fR). Pending watchers with higher priority will be invoked |
|
|
908 | before watchers with lower priority, but priority will not keep watchers |
|
|
909 | from being executed (except for \f(CW\*(C`ev_idle\*(C'\fR watchers). |
|
|
910 | .Sp |
|
|
911 | This means that priorities are \fIonly\fR used for ordering callback |
|
|
912 | invocation after new events have been received. This is useful, for |
|
|
913 | example, to reduce latency after idling, or more often, to bind two |
|
|
914 | watchers on the same event and make sure one is called first. |
|
|
915 | .Sp |
|
|
916 | If you need to suppress invocation when higher priority events are pending |
|
|
917 | you need to look at \f(CW\*(C`ev_idle\*(C'\fR watchers, which provide this functionality. |
|
|
918 | .Sp |
|
|
919 | The default priority used by watchers when no priority has been set is |
|
|
920 | always \f(CW0\fR, which is supposed to not be too high and not be too low :). |
|
|
921 | .Sp |
|
|
922 | Setting a priority outside the range of \f(CW\*(C`EV_MINPRI\*(C'\fR to \f(CW\*(C`EV_MAXPRI\*(C'\fR is |
|
|
923 | fine, as long as you do not mind that the priority value you query might |
|
|
924 | or might not have been adjusted to be within valid range. |
791 | .Sh "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0" |
925 | .Sh "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0" |
792 | .IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER" |
926 | .IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER" |
793 | Each watcher has, by default, a member \f(CW\*(C`void *data\*(C'\fR that you can change |
927 | Each watcher has, by default, a member \f(CW\*(C`void *data\*(C'\fR that you can change |
794 | and read at any time, libev will completely ignore it. This can be used |
928 | and read at any time, libev will completely ignore it. This can be used |
795 | to associate arbitrary data with your watcher. If you need more data and |
929 | to associate arbitrary data with your watcher. If you need more data and |
… | |
… | |
816 | \& struct my_io *w = (struct my_io *)w_; |
950 | \& struct my_io *w = (struct my_io *)w_; |
817 | \& ... |
951 | \& ... |
818 | \& } |
952 | \& } |
819 | .Ve |
953 | .Ve |
820 | .PP |
954 | .PP |
821 | More interesting and less C\-conformant ways of catsing your callback type |
955 | More interesting and less C\-conformant ways of casting your callback type |
822 | have been omitted.... |
956 | instead have been omitted. |
|
|
957 | .PP |
|
|
958 | Another common scenario is having some data structure with multiple |
|
|
959 | watchers: |
|
|
960 | .PP |
|
|
961 | .Vb 6 |
|
|
962 | \& struct my_biggy |
|
|
963 | \& { |
|
|
964 | \& int some_data; |
|
|
965 | \& ev_timer t1; |
|
|
966 | \& ev_timer t2; |
|
|
967 | \& } |
|
|
968 | .Ve |
|
|
969 | .PP |
|
|
970 | In this case getting the pointer to \f(CW\*(C`my_biggy\*(C'\fR is a bit more complicated, |
|
|
971 | you need to use \f(CW\*(C`offsetof\*(C'\fR: |
|
|
972 | .PP |
|
|
973 | .Vb 1 |
|
|
974 | \& #include <stddef.h> |
|
|
975 | .Ve |
|
|
976 | .PP |
|
|
977 | .Vb 6 |
|
|
978 | \& static void |
|
|
979 | \& t1_cb (EV_P_ struct ev_timer *w, int revents) |
|
|
980 | \& { |
|
|
981 | \& struct my_biggy big = (struct my_biggy * |
|
|
982 | \& (((char *)w) - offsetof (struct my_biggy, t1)); |
|
|
983 | \& } |
|
|
984 | .Ve |
|
|
985 | .PP |
|
|
986 | .Vb 6 |
|
|
987 | \& static void |
|
|
988 | \& t2_cb (EV_P_ struct ev_timer *w, int revents) |
|
|
989 | \& { |
|
|
990 | \& struct my_biggy big = (struct my_biggy * |
|
|
991 | \& (((char *)w) - offsetof (struct my_biggy, t2)); |
|
|
992 | \& } |
|
|
993 | .Ve |
823 | .SH "WATCHER TYPES" |
994 | .SH "WATCHER TYPES" |
824 | .IX Header "WATCHER TYPES" |
995 | .IX Header "WATCHER TYPES" |
825 | This section describes each watcher in detail, but will not repeat |
996 | This section describes each watcher in detail, but will not repeat |
826 | information given in the last section. |
997 | information given in the last section. Any initialisation/set macros, |
|
|
998 | functions and members specific to the watcher type are explained. |
|
|
999 | .PP |
|
|
1000 | Members are additionally marked with either \fI[read\-only]\fR, meaning that, |
|
|
1001 | while the watcher is active, you can look at the member and expect some |
|
|
1002 | sensible content, but you must not modify it (you can modify it while the |
|
|
1003 | watcher is stopped to your hearts content), or \fI[read\-write]\fR, which |
|
|
1004 | means you can expect it to have some sensible content while the watcher |
|
|
1005 | is active, but you can also modify it. Modifying it may not do something |
|
|
1006 | sensible or take immediate effect (or do anything at all), but libev will |
|
|
1007 | not crash or malfunction in any way. |
827 | .ie n .Sh """ev_io"" \- is this file descriptor readable or writable" |
1008 | .ie n .Sh """ev_io"" \- is this file descriptor readable or writable?" |
828 | .el .Sh "\f(CWev_io\fP \- is this file descriptor readable or writable" |
1009 | .el .Sh "\f(CWev_io\fP \- is this file descriptor readable or writable?" |
829 | .IX Subsection "ev_io - is this file descriptor readable or writable" |
1010 | .IX Subsection "ev_io - is this file descriptor readable or writable?" |
830 | I/O watchers check whether a file descriptor is readable or writable |
1011 | I/O watchers check whether a file descriptor is readable or writable |
831 | in each iteration of the event loop (This behaviour is called |
1012 | in each iteration of the event loop, or, more precisely, when reading |
832 | level-triggering because you keep receiving events as long as the |
1013 | would not block the process and writing would at least be able to write |
833 | condition persists. Remember you can stop the watcher if you don't want to |
1014 | some data. This behaviour is called level-triggering because you keep |
834 | act on the event and neither want to receive future events). |
1015 | receiving events as long as the condition persists. Remember you can stop |
|
|
1016 | the watcher if you don't want to act on the event and neither want to |
|
|
1017 | receive future events. |
835 | .PP |
1018 | .PP |
836 | In general you can register as many read and/or write event watchers per |
1019 | In general you can register as many read and/or write event watchers per |
837 | fd as you want (as long as you don't confuse yourself). Setting all file |
1020 | fd as you want (as long as you don't confuse yourself). Setting all file |
838 | descriptors to non-blocking mode is also usually a good idea (but not |
1021 | descriptors to non-blocking mode is also usually a good idea (but not |
839 | required if you know what you are doing). |
1022 | required if you know what you are doing). |
840 | .PP |
1023 | .PP |
841 | You have to be careful with dup'ed file descriptors, though. Some backends |
1024 | You have to be careful with dup'ed file descriptors, though. Some backends |
842 | (the linux epoll backend is a notable example) cannot handle dup'ed file |
1025 | (the linux epoll backend is a notable example) cannot handle dup'ed file |
843 | descriptors correctly if you register interest in two or more fds pointing |
1026 | descriptors correctly if you register interest in two or more fds pointing |
844 | to the same underlying file/socket etc. description (that is, they share |
1027 | to the same underlying file/socket/etc. description (that is, they share |
845 | the same underlying \*(L"file open\*(R"). |
1028 | the same underlying \*(L"file open\*(R"). |
846 | .PP |
1029 | .PP |
847 | If you must do this, then force the use of a known-to-be-good backend |
1030 | If you must do this, then force the use of a known-to-be-good backend |
848 | (at the time of this writing, this includes only \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR and |
1031 | (at the time of this writing, this includes only \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR and |
849 | \&\f(CW\*(C`EVBACKEND_POLL\*(C'\fR). |
1032 | \&\f(CW\*(C`EVBACKEND_POLL\*(C'\fR). |
|
|
1033 | .PP |
|
|
1034 | Another thing you have to watch out for is that it is quite easy to |
|
|
1035 | receive \*(L"spurious\*(R" readyness notifications, that is your callback might |
|
|
1036 | be called with \f(CW\*(C`EV_READ\*(C'\fR but a subsequent \f(CW\*(C`read\*(C'\fR(2) will actually block |
|
|
1037 | because there is no data. Not only are some backends known to create a |
|
|
1038 | lot of those (for example solaris ports), it is very easy to get into |
|
|
1039 | this situation even with a relatively standard program structure. Thus |
|
|
1040 | it is best to always use non-blocking I/O: An extra \f(CW\*(C`read\*(C'\fR(2) returning |
|
|
1041 | \&\f(CW\*(C`EAGAIN\*(C'\fR is far preferable to a program hanging until some data arrives. |
|
|
1042 | .PP |
|
|
1043 | If you cannot run the fd in non-blocking mode (for example you should not |
|
|
1044 | play around with an Xlib connection), then you have to seperately re-test |
|
|
1045 | wether a file descriptor is really ready with a known-to-be good interface |
|
|
1046 | such as poll (fortunately in our Xlib example, Xlib already does this on |
|
|
1047 | its own, so its quite safe to use). |
850 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
1048 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
851 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
1049 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
852 | .PD 0 |
1050 | .PD 0 |
853 | .IP "ev_io_set (ev_io *, int fd, int events)" 4 |
1051 | .IP "ev_io_set (ev_io *, int fd, int events)" 4 |
854 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
1052 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
855 | .PD |
1053 | .PD |
856 | Configures an \f(CW\*(C`ev_io\*(C'\fR watcher. The fd is the file descriptor to rceeive |
1054 | Configures an \f(CW\*(C`ev_io\*(C'\fR watcher. The \f(CW\*(C`fd\*(C'\fR is the file descriptor to |
857 | 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 | |
1055 | rceeive events for and events is either \f(CW\*(C`EV_READ\*(C'\fR, \f(CW\*(C`EV_WRITE\*(C'\fR or |
858 | EV_WRITE\*(C'\fR to receive the given events. |
1056 | \&\f(CW\*(C`EV_READ | EV_WRITE\*(C'\fR to receive the given events. |
859 | .Sp |
1057 | .IP "int fd [read\-only]" 4 |
860 | Please note that most of the more scalable backend mechanisms (for example |
1058 | .IX Item "int fd [read-only]" |
861 | epoll and solaris ports) can result in spurious readyness notifications |
1059 | The file descriptor being watched. |
862 | for file descriptors, so you practically need to use non-blocking I/O (and |
1060 | .IP "int events [read\-only]" 4 |
863 | treat callback invocation as hint only), or retest separately with a safe |
1061 | .IX Item "int events [read-only]" |
864 | interface before doing I/O (XLib can do this), or force the use of either |
1062 | The events being watched. |
865 | \&\f(CW\*(C`EVBACKEND_SELECT\*(C'\fR or \f(CW\*(C`EVBACKEND_POLL\*(C'\fR, which don't suffer from this |
|
|
866 | problem. Also note that it is quite easy to have your callback invoked |
|
|
867 | when the readyness condition is no longer valid even when employing |
|
|
868 | typical ways of handling events, so its a good idea to use non-blocking |
|
|
869 | I/O unconditionally. |
|
|
870 | .PP |
1063 | .PP |
871 | Example: call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well |
1064 | Example: Call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well |
872 | readable, but only once. Since it is likely line\-buffered, you could |
1065 | readable, but only once. Since it is likely line\-buffered, you could |
873 | attempt to read a whole line in the callback: |
1066 | attempt to read a whole line in the callback. |
874 | .PP |
1067 | .PP |
875 | .Vb 6 |
1068 | .Vb 6 |
876 | \& static void |
1069 | \& static void |
877 | \& stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
1070 | \& stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
878 | \& { |
1071 | \& { |
… | |
… | |
887 | \& struct ev_io stdin_readable; |
1080 | \& struct ev_io stdin_readable; |
888 | \& ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ); |
1081 | \& ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ); |
889 | \& ev_io_start (loop, &stdin_readable); |
1082 | \& ev_io_start (loop, &stdin_readable); |
890 | \& ev_loop (loop, 0); |
1083 | \& ev_loop (loop, 0); |
891 | .Ve |
1084 | .Ve |
892 | .ie n .Sh """ev_timer"" \- relative and optionally recurring timeouts" |
1085 | .ie n .Sh """ev_timer"" \- relative and optionally repeating timeouts" |
893 | .el .Sh "\f(CWev_timer\fP \- relative and optionally recurring timeouts" |
1086 | .el .Sh "\f(CWev_timer\fP \- relative and optionally repeating timeouts" |
894 | .IX Subsection "ev_timer - relative and optionally recurring timeouts" |
1087 | .IX Subsection "ev_timer - relative and optionally repeating timeouts" |
895 | Timer watchers are simple relative timers that generate an event after a |
1088 | Timer watchers are simple relative timers that generate an event after a |
896 | given time, and optionally repeating in regular intervals after that. |
1089 | given time, and optionally repeating in regular intervals after that. |
897 | .PP |
1090 | .PP |
898 | The timers are based on real time, that is, if you register an event that |
1091 | The timers are based on real time, that is, if you register an event that |
899 | times out after an hour and you reset your system clock to last years |
1092 | times out after an hour and you reset your system clock to last years |
… | |
… | |
933 | .IP "ev_timer_again (loop)" 4 |
1126 | .IP "ev_timer_again (loop)" 4 |
934 | .IX Item "ev_timer_again (loop)" |
1127 | .IX Item "ev_timer_again (loop)" |
935 | This will act as if the timer timed out and restart it again if it is |
1128 | This will act as if the timer timed out and restart it again if it is |
936 | repeating. The exact semantics are: |
1129 | repeating. The exact semantics are: |
937 | .Sp |
1130 | .Sp |
|
|
1131 | If the timer is pending, its pending status is cleared. |
|
|
1132 | .Sp |
938 | If the timer is started but nonrepeating, stop it. |
1133 | If the timer is started but nonrepeating, stop it (as if it timed out). |
939 | .Sp |
1134 | .Sp |
940 | If the timer is repeating, either start it if necessary (with the repeat |
1135 | If the timer is repeating, either start it if necessary (with the |
941 | value), or reset the running timer to the repeat value. |
1136 | \&\f(CW\*(C`repeat\*(C'\fR value), or reset the running timer to the \f(CW\*(C`repeat\*(C'\fR value. |
942 | .Sp |
1137 | .Sp |
943 | This sounds a bit complicated, but here is a useful and typical |
1138 | This sounds a bit complicated, but here is a useful and typical |
944 | example: Imagine you have a tcp connection and you want a so-called idle |
1139 | example: Imagine you have a tcp connection and you want a so-called idle |
945 | timeout, that is, you want to be called when there have been, say, 60 |
1140 | timeout, that is, you want to be called when there have been, say, 60 |
946 | seconds of inactivity on the socket. The easiest way to do this is to |
1141 | seconds of inactivity on the socket. The easiest way to do this is to |
947 | configure an \f(CW\*(C`ev_timer\*(C'\fR with after=repeat=60 and calling ev_timer_again each |
1142 | configure an \f(CW\*(C`ev_timer\*(C'\fR with a \f(CW\*(C`repeat\*(C'\fR value of \f(CW60\fR and then call |
948 | time you successfully read or write some data. If you go into an idle |
1143 | \&\f(CW\*(C`ev_timer_again\*(C'\fR each time you successfully read or write some data. If |
949 | state where you do not expect data to travel on the socket, you can stop |
1144 | you go into an idle state where you do not expect data to travel on the |
950 | the timer, and again will automatically restart it if need be. |
1145 | socket, you can \f(CW\*(C`ev_timer_stop\*(C'\fR the timer, and \f(CW\*(C`ev_timer_again\*(C'\fR will |
|
|
1146 | automatically restart it if need be. |
|
|
1147 | .Sp |
|
|
1148 | That means you can ignore the \f(CW\*(C`after\*(C'\fR value and \f(CW\*(C`ev_timer_start\*(C'\fR |
|
|
1149 | altogether and only ever use the \f(CW\*(C`repeat\*(C'\fR value and \f(CW\*(C`ev_timer_again\*(C'\fR: |
|
|
1150 | .Sp |
|
|
1151 | .Vb 8 |
|
|
1152 | \& ev_timer_init (timer, callback, 0., 5.); |
|
|
1153 | \& ev_timer_again (loop, timer); |
|
|
1154 | \& ... |
|
|
1155 | \& timer->again = 17.; |
|
|
1156 | \& ev_timer_again (loop, timer); |
|
|
1157 | \& ... |
|
|
1158 | \& timer->again = 10.; |
|
|
1159 | \& ev_timer_again (loop, timer); |
|
|
1160 | .Ve |
|
|
1161 | .Sp |
|
|
1162 | This is more slightly efficient then stopping/starting the timer each time |
|
|
1163 | you want to modify its timeout value. |
|
|
1164 | .IP "ev_tstamp repeat [read\-write]" 4 |
|
|
1165 | .IX Item "ev_tstamp repeat [read-write]" |
|
|
1166 | The current \f(CW\*(C`repeat\*(C'\fR value. Will be used each time the watcher times out |
|
|
1167 | or \f(CW\*(C`ev_timer_again\*(C'\fR is called and determines the next timeout (if any), |
|
|
1168 | which is also when any modifications are taken into account. |
951 | .PP |
1169 | .PP |
952 | Example: create a timer that fires after 60 seconds. |
1170 | Example: Create a timer that fires after 60 seconds. |
953 | .PP |
1171 | .PP |
954 | .Vb 5 |
1172 | .Vb 5 |
955 | \& static void |
1173 | \& static void |
956 | \& one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1174 | \& one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
957 | \& { |
1175 | \& { |
… | |
… | |
963 | \& struct ev_timer mytimer; |
1181 | \& struct ev_timer mytimer; |
964 | \& ev_timer_init (&mytimer, one_minute_cb, 60., 0.); |
1182 | \& ev_timer_init (&mytimer, one_minute_cb, 60., 0.); |
965 | \& ev_timer_start (loop, &mytimer); |
1183 | \& ev_timer_start (loop, &mytimer); |
966 | .Ve |
1184 | .Ve |
967 | .PP |
1185 | .PP |
968 | Example: create a timeout timer that times out after 10 seconds of |
1186 | Example: Create a timeout timer that times out after 10 seconds of |
969 | inactivity. |
1187 | inactivity. |
970 | .PP |
1188 | .PP |
971 | .Vb 5 |
1189 | .Vb 5 |
972 | \& static void |
1190 | \& static void |
973 | \& timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1191 | \& timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
… | |
… | |
986 | .Vb 3 |
1204 | .Vb 3 |
987 | \& // and in some piece of code that gets executed on any "activity": |
1205 | \& // and in some piece of code that gets executed on any "activity": |
988 | \& // reset the timeout to start ticking again at 10 seconds |
1206 | \& // reset the timeout to start ticking again at 10 seconds |
989 | \& ev_timer_again (&mytimer); |
1207 | \& ev_timer_again (&mytimer); |
990 | .Ve |
1208 | .Ve |
991 | .ie n .Sh """ev_periodic"" \- to cron or not to cron" |
1209 | .ie n .Sh """ev_periodic"" \- to cron or not to cron?" |
992 | .el .Sh "\f(CWev_periodic\fP \- to cron or not to cron" |
1210 | .el .Sh "\f(CWev_periodic\fP \- to cron or not to cron?" |
993 | .IX Subsection "ev_periodic - to cron or not to cron" |
1211 | .IX Subsection "ev_periodic - to cron or not to cron?" |
994 | Periodic watchers are also timers of a kind, but they are very versatile |
1212 | Periodic watchers are also timers of a kind, but they are very versatile |
995 | (and unfortunately a bit complex). |
1213 | (and unfortunately a bit complex). |
996 | .PP |
1214 | .PP |
997 | Unlike \f(CW\*(C`ev_timer\*(C'\fR's, they are not based on real time (or relative time) |
1215 | Unlike \f(CW\*(C`ev_timer\*(C'\fR's, they are not based on real time (or relative time) |
998 | but on wallclock time (absolute time). You can tell a periodic watcher |
1216 | but on wallclock time (absolute time). You can tell a periodic watcher |
… | |
… | |
1087 | .IX Item "ev_periodic_again (loop, ev_periodic *)" |
1305 | .IX Item "ev_periodic_again (loop, ev_periodic *)" |
1088 | Simply stops and restarts the periodic watcher again. This is only useful |
1306 | Simply stops and restarts the periodic watcher again. This is only useful |
1089 | when you changed some parameters or the reschedule callback would return |
1307 | when you changed some parameters or the reschedule callback would return |
1090 | a different time than the last time it was called (e.g. in a crond like |
1308 | a different time than the last time it was called (e.g. in a crond like |
1091 | program when the crontabs have changed). |
1309 | program when the crontabs have changed). |
|
|
1310 | .IP "ev_tstamp interval [read\-write]" 4 |
|
|
1311 | .IX Item "ev_tstamp interval [read-write]" |
|
|
1312 | The current interval value. Can be modified any time, but changes only |
|
|
1313 | take effect when the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being |
|
|
1314 | called. |
|
|
1315 | .IP "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read\-write]" 4 |
|
|
1316 | .IX Item "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write]" |
|
|
1317 | The current reschedule callback, or \f(CW0\fR, if this functionality is |
|
|
1318 | switched off. Can be changed any time, but changes only take effect when |
|
|
1319 | the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called. |
1092 | .PP |
1320 | .PP |
1093 | Example: call a callback every hour, or, more precisely, whenever the |
1321 | Example: Call a callback every hour, or, more precisely, whenever the |
1094 | system clock is divisible by 3600. The callback invocation times have |
1322 | system clock is divisible by 3600. The callback invocation times have |
1095 | potentially a lot of jittering, but good long-term stability. |
1323 | potentially a lot of jittering, but good long-term stability. |
1096 | .PP |
1324 | .PP |
1097 | .Vb 5 |
1325 | .Vb 5 |
1098 | \& static void |
1326 | \& static void |
… | |
… | |
1106 | \& struct ev_periodic hourly_tick; |
1334 | \& struct ev_periodic hourly_tick; |
1107 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); |
1335 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); |
1108 | \& ev_periodic_start (loop, &hourly_tick); |
1336 | \& ev_periodic_start (loop, &hourly_tick); |
1109 | .Ve |
1337 | .Ve |
1110 | .PP |
1338 | .PP |
1111 | Example: the same as above, but use a reschedule callback to do it: |
1339 | Example: The same as above, but use a reschedule callback to do it: |
1112 | .PP |
1340 | .PP |
1113 | .Vb 1 |
1341 | .Vb 1 |
1114 | \& #include <math.h> |
1342 | \& #include <math.h> |
1115 | .Ve |
1343 | .Ve |
1116 | .PP |
1344 | .PP |
… | |
… | |
1124 | .PP |
1352 | .PP |
1125 | .Vb 1 |
1353 | .Vb 1 |
1126 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); |
1354 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); |
1127 | .Ve |
1355 | .Ve |
1128 | .PP |
1356 | .PP |
1129 | Example: call a callback every hour, starting now: |
1357 | Example: Call a callback every hour, starting now: |
1130 | .PP |
1358 | .PP |
1131 | .Vb 4 |
1359 | .Vb 4 |
1132 | \& struct ev_periodic hourly_tick; |
1360 | \& struct ev_periodic hourly_tick; |
1133 | \& ev_periodic_init (&hourly_tick, clock_cb, |
1361 | \& ev_periodic_init (&hourly_tick, clock_cb, |
1134 | \& fmod (ev_now (loop), 3600.), 3600., 0); |
1362 | \& fmod (ev_now (loop), 3600.), 3600., 0); |
1135 | \& ev_periodic_start (loop, &hourly_tick); |
1363 | \& ev_periodic_start (loop, &hourly_tick); |
1136 | .Ve |
1364 | .Ve |
1137 | .ie n .Sh """ev_signal"" \- signal me when a signal gets signalled" |
1365 | .ie n .Sh """ev_signal"" \- signal me when a signal gets signalled!" |
1138 | .el .Sh "\f(CWev_signal\fP \- signal me when a signal gets signalled" |
1366 | .el .Sh "\f(CWev_signal\fP \- signal me when a signal gets signalled!" |
1139 | .IX Subsection "ev_signal - signal me when a signal gets signalled" |
1367 | .IX Subsection "ev_signal - signal me when a signal gets signalled!" |
1140 | Signal watchers will trigger an event when the process receives a specific |
1368 | Signal watchers will trigger an event when the process receives a specific |
1141 | signal one or more times. Even though signals are very asynchronous, libev |
1369 | signal one or more times. Even though signals are very asynchronous, libev |
1142 | will try it's best to deliver signals synchronously, i.e. as part of the |
1370 | will try it's best to deliver signals synchronously, i.e. as part of the |
1143 | normal event processing, like any other event. |
1371 | normal event processing, like any other event. |
1144 | .PP |
1372 | .PP |
… | |
… | |
1154 | .IP "ev_signal_set (ev_signal *, int signum)" 4 |
1382 | .IP "ev_signal_set (ev_signal *, int signum)" 4 |
1155 | .IX Item "ev_signal_set (ev_signal *, int signum)" |
1383 | .IX Item "ev_signal_set (ev_signal *, int signum)" |
1156 | .PD |
1384 | .PD |
1157 | Configures the watcher to trigger on the given signal number (usually one |
1385 | Configures the watcher to trigger on the given signal number (usually one |
1158 | of the \f(CW\*(C`SIGxxx\*(C'\fR constants). |
1386 | of the \f(CW\*(C`SIGxxx\*(C'\fR constants). |
|
|
1387 | .IP "int signum [read\-only]" 4 |
|
|
1388 | .IX Item "int signum [read-only]" |
|
|
1389 | The signal the watcher watches out for. |
1159 | .ie n .Sh """ev_child"" \- wait for pid status changes" |
1390 | .ie n .Sh """ev_child"" \- watch out for process status changes" |
1160 | .el .Sh "\f(CWev_child\fP \- wait for pid status changes" |
1391 | .el .Sh "\f(CWev_child\fP \- watch out for process status changes" |
1161 | .IX Subsection "ev_child - wait for pid status changes" |
1392 | .IX Subsection "ev_child - watch out for process status changes" |
1162 | Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to |
1393 | Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to |
1163 | some child status changes (most typically when a child of yours dies). |
1394 | some child status changes (most typically when a child of yours dies). |
1164 | .IP "ev_child_init (ev_child *, callback, int pid)" 4 |
1395 | .IP "ev_child_init (ev_child *, callback, int pid)" 4 |
1165 | .IX Item "ev_child_init (ev_child *, callback, int pid)" |
1396 | .IX Item "ev_child_init (ev_child *, callback, int pid)" |
1166 | .PD 0 |
1397 | .PD 0 |
… | |
… | |
1171 | \&\fIany\fR process if \f(CW\*(C`pid\*(C'\fR is specified as \f(CW0\fR). The callback can look |
1402 | \&\fIany\fR process if \f(CW\*(C`pid\*(C'\fR is specified as \f(CW0\fR). The callback can look |
1172 | at the \f(CW\*(C`rstatus\*(C'\fR member of the \f(CW\*(C`ev_child\*(C'\fR watcher structure to see |
1403 | at the \f(CW\*(C`rstatus\*(C'\fR member of the \f(CW\*(C`ev_child\*(C'\fR watcher structure to see |
1173 | the status word (use the macros from \f(CW\*(C`sys/wait.h\*(C'\fR and see your systems |
1404 | the status word (use the macros from \f(CW\*(C`sys/wait.h\*(C'\fR and see your systems |
1174 | \&\f(CW\*(C`waitpid\*(C'\fR documentation). The \f(CW\*(C`rpid\*(C'\fR member contains the pid of the |
1405 | \&\f(CW\*(C`waitpid\*(C'\fR documentation). The \f(CW\*(C`rpid\*(C'\fR member contains the pid of the |
1175 | process causing the status change. |
1406 | process causing the status change. |
|
|
1407 | .IP "int pid [read\-only]" 4 |
|
|
1408 | .IX Item "int pid [read-only]" |
|
|
1409 | The process id this watcher watches out for, or \f(CW0\fR, meaning any process id. |
|
|
1410 | .IP "int rpid [read\-write]" 4 |
|
|
1411 | .IX Item "int rpid [read-write]" |
|
|
1412 | The process id that detected a status change. |
|
|
1413 | .IP "int rstatus [read\-write]" 4 |
|
|
1414 | .IX Item "int rstatus [read-write]" |
|
|
1415 | The process exit/trace status caused by \f(CW\*(C`rpid\*(C'\fR (see your systems |
|
|
1416 | \&\f(CW\*(C`waitpid\*(C'\fR and \f(CW\*(C`sys/wait.h\*(C'\fR documentation for details). |
1176 | .PP |
1417 | .PP |
1177 | Example: try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0. |
1418 | Example: Try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0. |
1178 | .PP |
1419 | .PP |
1179 | .Vb 5 |
1420 | .Vb 5 |
1180 | \& static void |
1421 | \& static void |
1181 | \& sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
1422 | \& sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
1182 | \& { |
1423 | \& { |
… | |
… | |
1187 | .Vb 3 |
1428 | .Vb 3 |
1188 | \& struct ev_signal signal_watcher; |
1429 | \& struct ev_signal signal_watcher; |
1189 | \& ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
1430 | \& ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
1190 | \& ev_signal_start (loop, &sigint_cb); |
1431 | \& ev_signal_start (loop, &sigint_cb); |
1191 | .Ve |
1432 | .Ve |
|
|
1433 | .ie n .Sh """ev_stat"" \- did the file attributes just change?" |
|
|
1434 | .el .Sh "\f(CWev_stat\fP \- did the file attributes just change?" |
|
|
1435 | .IX Subsection "ev_stat - did the file attributes just change?" |
|
|
1436 | This watches a filesystem path for attribute changes. That is, it calls |
|
|
1437 | \&\f(CW\*(C`stat\*(C'\fR regularly (or when the \s-1OS\s0 says it changed) and sees if it changed |
|
|
1438 | compared to the last time, invoking the callback if it did. |
|
|
1439 | .PP |
|
|
1440 | The path does not need to exist: changing from \*(L"path exists\*(R" to \*(L"path does |
|
|
1441 | not exist\*(R" is a status change like any other. The condition \*(L"path does |
|
|
1442 | not exist\*(R" is signified by the \f(CW\*(C`st_nlink\*(C'\fR field being zero (which is |
|
|
1443 | otherwise always forced to be at least one) and all the other fields of |
|
|
1444 | the stat buffer having unspecified contents. |
|
|
1445 | .PP |
|
|
1446 | The path \fIshould\fR be absolute and \fImust not\fR end in a slash. If it is |
|
|
1447 | relative and your working directory changes, the behaviour is undefined. |
|
|
1448 | .PP |
|
|
1449 | Since there is no standard to do this, the portable implementation simply |
|
|
1450 | calls \f(CW\*(C`stat (2)\*(C'\fR regularly on the path to see if it changed somehow. You |
|
|
1451 | can specify a recommended polling interval for this case. If you specify |
|
|
1452 | a polling interval of \f(CW0\fR (highly recommended!) then a \fIsuitable, |
|
|
1453 | unspecified default\fR value will be used (which you can expect to be around |
|
|
1454 | five seconds, although this might change dynamically). Libev will also |
|
|
1455 | impose a minimum interval which is currently around \f(CW0.1\fR, but thats |
|
|
1456 | usually overkill. |
|
|
1457 | .PP |
|
|
1458 | This watcher type is not meant for massive numbers of stat watchers, |
|
|
1459 | as even with OS-supported change notifications, this can be |
|
|
1460 | resource\-intensive. |
|
|
1461 | .PP |
|
|
1462 | At the time of this writing, only the Linux inotify interface is |
|
|
1463 | implemented (implementing kqueue support is left as an exercise for the |
|
|
1464 | reader). Inotify will be used to give hints only and should not change the |
|
|
1465 | semantics of \f(CW\*(C`ev_stat\*(C'\fR watchers, which means that libev sometimes needs |
|
|
1466 | to fall back to regular polling again even with inotify, but changes are |
|
|
1467 | usually detected immediately, and if the file exists there will be no |
|
|
1468 | polling. |
|
|
1469 | .IP "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" 4 |
|
|
1470 | .IX Item "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" |
|
|
1471 | .PD 0 |
|
|
1472 | .IP "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" 4 |
|
|
1473 | .IX Item "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" |
|
|
1474 | .PD |
|
|
1475 | Configures the watcher to wait for status changes of the given |
|
|
1476 | \&\f(CW\*(C`path\*(C'\fR. The \f(CW\*(C`interval\*(C'\fR is a hint on how quickly a change is expected to |
|
|
1477 | be detected and should normally be specified as \f(CW0\fR to let libev choose |
|
|
1478 | a suitable value. The memory pointed to by \f(CW\*(C`path\*(C'\fR must point to the same |
|
|
1479 | path for as long as the watcher is active. |
|
|
1480 | .Sp |
|
|
1481 | The callback will be receive \f(CW\*(C`EV_STAT\*(C'\fR when a change was detected, |
|
|
1482 | relative to the attributes at the time the watcher was started (or the |
|
|
1483 | last change was detected). |
|
|
1484 | .IP "ev_stat_stat (ev_stat *)" 4 |
|
|
1485 | .IX Item "ev_stat_stat (ev_stat *)" |
|
|
1486 | Updates the stat buffer immediately with new values. If you change the |
|
|
1487 | watched path in your callback, you could call this fucntion to avoid |
|
|
1488 | detecting this change (while introducing a race condition). Can also be |
|
|
1489 | useful simply to find out the new values. |
|
|
1490 | .IP "ev_statdata attr [read\-only]" 4 |
|
|
1491 | .IX Item "ev_statdata attr [read-only]" |
|
|
1492 | The most-recently detected attributes of the file. Although the type is of |
|
|
1493 | \&\f(CW\*(C`ev_statdata\*(C'\fR, this is usually the (or one of the) \f(CW\*(C`struct stat\*(C'\fR types |
|
|
1494 | suitable for your system. If the \f(CW\*(C`st_nlink\*(C'\fR member is \f(CW0\fR, then there |
|
|
1495 | was some error while \f(CW\*(C`stat\*(C'\fRing the file. |
|
|
1496 | .IP "ev_statdata prev [read\-only]" 4 |
|
|
1497 | .IX Item "ev_statdata prev [read-only]" |
|
|
1498 | The previous attributes of the file. The callback gets invoked whenever |
|
|
1499 | \&\f(CW\*(C`prev\*(C'\fR != \f(CW\*(C`attr\*(C'\fR. |
|
|
1500 | .IP "ev_tstamp interval [read\-only]" 4 |
|
|
1501 | .IX Item "ev_tstamp interval [read-only]" |
|
|
1502 | The specified interval. |
|
|
1503 | .IP "const char *path [read\-only]" 4 |
|
|
1504 | .IX Item "const char *path [read-only]" |
|
|
1505 | The filesystem path that is being watched. |
|
|
1506 | .PP |
|
|
1507 | Example: Watch \f(CW\*(C`/etc/passwd\*(C'\fR for attribute changes. |
|
|
1508 | .PP |
|
|
1509 | .Vb 15 |
|
|
1510 | \& static void |
|
|
1511 | \& passwd_cb (struct ev_loop *loop, ev_stat *w, int revents) |
|
|
1512 | \& { |
|
|
1513 | \& /* /etc/passwd changed in some way */ |
|
|
1514 | \& if (w->attr.st_nlink) |
|
|
1515 | \& { |
|
|
1516 | \& printf ("passwd current size %ld\en", (long)w->attr.st_size); |
|
|
1517 | \& printf ("passwd current atime %ld\en", (long)w->attr.st_mtime); |
|
|
1518 | \& printf ("passwd current mtime %ld\en", (long)w->attr.st_mtime); |
|
|
1519 | \& } |
|
|
1520 | \& else |
|
|
1521 | \& /* you shalt not abuse printf for puts */ |
|
|
1522 | \& puts ("wow, /etc/passwd is not there, expect problems. " |
|
|
1523 | \& "if this is windows, they already arrived\en"); |
|
|
1524 | \& } |
|
|
1525 | .Ve |
|
|
1526 | .PP |
|
|
1527 | .Vb 2 |
|
|
1528 | \& ... |
|
|
1529 | \& ev_stat passwd; |
|
|
1530 | .Ve |
|
|
1531 | .PP |
|
|
1532 | .Vb 2 |
|
|
1533 | \& ev_stat_init (&passwd, passwd_cb, "/etc/passwd"); |
|
|
1534 | \& ev_stat_start (loop, &passwd); |
|
|
1535 | .Ve |
1192 | .ie n .Sh """ev_idle"" \- when you've got nothing better to do" |
1536 | .ie n .Sh """ev_idle"" \- when you've got nothing better to do..." |
1193 | .el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do" |
1537 | .el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do..." |
1194 | .IX Subsection "ev_idle - when you've got nothing better to do" |
1538 | .IX Subsection "ev_idle - when you've got nothing better to do..." |
1195 | Idle watchers trigger events when there are no other events are pending |
1539 | Idle watchers trigger events when no other events of the same or higher |
1196 | (prepare, check and other idle watchers do not count). That is, as long |
1540 | priority are pending (prepare, check and other idle watchers do not |
1197 | as your process is busy handling sockets or timeouts (or even signals, |
1541 | count). |
1198 | imagine) it will not be triggered. But when your process is idle all idle |
1542 | .PP |
1199 | watchers are being called again and again, once per event loop iteration \- |
1543 | That is, as long as your process is busy handling sockets or timeouts |
|
|
1544 | (or even signals, imagine) of the same or higher priority it will not be |
|
|
1545 | triggered. But when your process is idle (or only lower-priority watchers |
|
|
1546 | are pending), the idle watchers are being called once per event loop |
1200 | until stopped, that is, or your process receives more events and becomes |
1547 | iteration \- until stopped, that is, or your process receives more events |
1201 | busy. |
1548 | and becomes busy again with higher priority stuff. |
1202 | .PP |
1549 | .PP |
1203 | The most noteworthy effect is that as long as any idle watchers are |
1550 | The most noteworthy effect is that as long as any idle watchers are |
1204 | active, the process will not block when waiting for new events. |
1551 | active, the process will not block when waiting for new events. |
1205 | .PP |
1552 | .PP |
1206 | Apart from keeping your process non-blocking (which is a useful |
1553 | Apart from keeping your process non-blocking (which is a useful |
… | |
… | |
1211 | .IX Item "ev_idle_init (ev_signal *, callback)" |
1558 | .IX Item "ev_idle_init (ev_signal *, callback)" |
1212 | Initialises and configures the idle watcher \- it has no parameters of any |
1559 | Initialises and configures the idle watcher \- it has no parameters of any |
1213 | kind. There is a \f(CW\*(C`ev_idle_set\*(C'\fR macro, but using it is utterly pointless, |
1560 | kind. There is a \f(CW\*(C`ev_idle_set\*(C'\fR macro, but using it is utterly pointless, |
1214 | believe me. |
1561 | believe me. |
1215 | .PP |
1562 | .PP |
1216 | Example: dynamically allocate an \f(CW\*(C`ev_idle\*(C'\fR, start it, and in the |
1563 | Example: Dynamically allocate an \f(CW\*(C`ev_idle\*(C'\fR watcher, start it, and in the |
1217 | callback, free it. Alos, use no error checking, as usual. |
1564 | callback, free it. Also, use no error checking, as usual. |
1218 | .PP |
1565 | .PP |
1219 | .Vb 7 |
1566 | .Vb 7 |
1220 | \& static void |
1567 | \& static void |
1221 | \& idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
1568 | \& idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
1222 | \& { |
1569 | \& { |
… | |
… | |
1229 | .Vb 3 |
1576 | .Vb 3 |
1230 | \& struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle)); |
1577 | \& struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle)); |
1231 | \& ev_idle_init (idle_watcher, idle_cb); |
1578 | \& ev_idle_init (idle_watcher, idle_cb); |
1232 | \& ev_idle_start (loop, idle_cb); |
1579 | \& ev_idle_start (loop, idle_cb); |
1233 | .Ve |
1580 | .Ve |
1234 | .ie n .Sh """ev_prepare""\fP and \f(CW""ev_check"" \- customise your event loop" |
1581 | .ie n .Sh """ev_prepare""\fP and \f(CW""ev_check"" \- customise your event loop!" |
1235 | .el .Sh "\f(CWev_prepare\fP and \f(CWev_check\fP \- customise your event loop" |
1582 | .el .Sh "\f(CWev_prepare\fP and \f(CWev_check\fP \- customise your event loop!" |
1236 | .IX Subsection "ev_prepare and ev_check - customise your event loop" |
1583 | .IX Subsection "ev_prepare and ev_check - customise your event loop!" |
1237 | Prepare and check watchers are usually (but not always) used in tandem: |
1584 | Prepare and check watchers are usually (but not always) used in tandem: |
1238 | prepare watchers get invoked before the process blocks and check watchers |
1585 | prepare watchers get invoked before the process blocks and check watchers |
1239 | afterwards. |
1586 | afterwards. |
1240 | .PP |
1587 | .PP |
|
|
1588 | You \fImust not\fR call \f(CW\*(C`ev_loop\*(C'\fR or similar functions that enter |
|
|
1589 | the current event loop from either \f(CW\*(C`ev_prepare\*(C'\fR or \f(CW\*(C`ev_check\*(C'\fR |
|
|
1590 | watchers. Other loops than the current one are fine, however. The |
|
|
1591 | rationale behind this is that you do not need to check for recursion in |
|
|
1592 | those watchers, i.e. the sequence will always be \f(CW\*(C`ev_prepare\*(C'\fR, blocking, |
|
|
1593 | \&\f(CW\*(C`ev_check\*(C'\fR so if you have one watcher of each kind they will always be |
|
|
1594 | called in pairs bracketing the blocking call. |
|
|
1595 | .PP |
1241 | Their main purpose is to integrate other event mechanisms into libev and |
1596 | Their main purpose is to integrate other event mechanisms into libev and |
1242 | their use is somewhat advanced. This could be used, for example, to track |
1597 | their use is somewhat advanced. This could be used, for example, to track |
1243 | variable changes, implement your own watchers, integrate net-snmp or a |
1598 | variable changes, implement your own watchers, integrate net-snmp or a |
1244 | coroutine library and lots more. |
1599 | coroutine library and lots more. They are also occasionally useful if |
|
|
1600 | you cache some data and want to flush it before blocking (for example, |
|
|
1601 | in X programs you might want to do an \f(CW\*(C`XFlush ()\*(C'\fR in an \f(CW\*(C`ev_prepare\*(C'\fR |
|
|
1602 | watcher). |
1245 | .PP |
1603 | .PP |
1246 | This is done by examining in each prepare call which file descriptors need |
1604 | This is done by examining in each prepare call which file descriptors need |
1247 | to be watched by the other library, registering \f(CW\*(C`ev_io\*(C'\fR watchers for |
1605 | to be watched by the other library, registering \f(CW\*(C`ev_io\*(C'\fR watchers for |
1248 | them and starting an \f(CW\*(C`ev_timer\*(C'\fR watcher for any timeouts (many libraries |
1606 | them and starting an \f(CW\*(C`ev_timer\*(C'\fR watcher for any timeouts (many libraries |
1249 | provide just this functionality). Then, in the check watcher you check for |
1607 | provide just this functionality). Then, in the check watcher you check for |
… | |
… | |
1268 | .PD |
1626 | .PD |
1269 | Initialises and configures the prepare or check watcher \- they have no |
1627 | Initialises and configures the prepare or check watcher \- they have no |
1270 | parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR |
1628 | parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR |
1271 | macros, but using them is utterly, utterly and completely pointless. |
1629 | macros, but using them is utterly, utterly and completely pointless. |
1272 | .PP |
1630 | .PP |
1273 | Example: *TODO*. |
1631 | Example: To include a library such as adns, you would add \s-1IO\s0 watchers |
|
|
1632 | and a timeout watcher in a prepare handler, as required by libadns, and |
|
|
1633 | in a check watcher, destroy them and call into libadns. What follows is |
|
|
1634 | pseudo-code only of course: |
|
|
1635 | .PP |
|
|
1636 | .Vb 2 |
|
|
1637 | \& static ev_io iow [nfd]; |
|
|
1638 | \& static ev_timer tw; |
|
|
1639 | .Ve |
|
|
1640 | .PP |
|
|
1641 | .Vb 9 |
|
|
1642 | \& static void |
|
|
1643 | \& io_cb (ev_loop *loop, ev_io *w, int revents) |
|
|
1644 | \& { |
|
|
1645 | \& // set the relevant poll flags |
|
|
1646 | \& // could also call adns_processreadable etc. here |
|
|
1647 | \& struct pollfd *fd = (struct pollfd *)w->data; |
|
|
1648 | \& if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
|
|
1649 | \& if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
|
|
1650 | \& } |
|
|
1651 | .Ve |
|
|
1652 | .PP |
|
|
1653 | .Vb 8 |
|
|
1654 | \& // create io watchers for each fd and a timer before blocking |
|
|
1655 | \& static void |
|
|
1656 | \& adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
|
|
1657 | \& { |
|
|
1658 | \& int timeout = 3600000; |
|
|
1659 | \& struct pollfd fds [nfd]; |
|
|
1660 | \& // actual code will need to loop here and realloc etc. |
|
|
1661 | \& adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
|
|
1662 | .Ve |
|
|
1663 | .PP |
|
|
1664 | .Vb 3 |
|
|
1665 | \& /* the callback is illegal, but won't be called as we stop during check */ |
|
|
1666 | \& ev_timer_init (&tw, 0, timeout * 1e-3); |
|
|
1667 | \& ev_timer_start (loop, &tw); |
|
|
1668 | .Ve |
|
|
1669 | .PP |
|
|
1670 | .Vb 6 |
|
|
1671 | \& // create on ev_io per pollfd |
|
|
1672 | \& for (int i = 0; i < nfd; ++i) |
|
|
1673 | \& { |
|
|
1674 | \& ev_io_init (iow + i, io_cb, fds [i].fd, |
|
|
1675 | \& ((fds [i].events & POLLIN ? EV_READ : 0) |
|
|
1676 | \& | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
|
|
1677 | .Ve |
|
|
1678 | .PP |
|
|
1679 | .Vb 5 |
|
|
1680 | \& fds [i].revents = 0; |
|
|
1681 | \& iow [i].data = fds + i; |
|
|
1682 | \& ev_io_start (loop, iow + i); |
|
|
1683 | \& } |
|
|
1684 | \& } |
|
|
1685 | .Ve |
|
|
1686 | .PP |
|
|
1687 | .Vb 5 |
|
|
1688 | \& // stop all watchers after blocking |
|
|
1689 | \& static void |
|
|
1690 | \& adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
|
|
1691 | \& { |
|
|
1692 | \& ev_timer_stop (loop, &tw); |
|
|
1693 | .Ve |
|
|
1694 | .PP |
|
|
1695 | .Vb 2 |
|
|
1696 | \& for (int i = 0; i < nfd; ++i) |
|
|
1697 | \& ev_io_stop (loop, iow + i); |
|
|
1698 | .Ve |
|
|
1699 | .PP |
|
|
1700 | .Vb 2 |
|
|
1701 | \& adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
|
|
1702 | \& } |
|
|
1703 | .Ve |
1274 | .ie n .Sh """ev_embed"" \- when one backend isn't enough" |
1704 | .ie n .Sh """ev_embed"" \- when one backend isn't enough..." |
1275 | .el .Sh "\f(CWev_embed\fP \- when one backend isn't enough" |
1705 | .el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..." |
1276 | .IX Subsection "ev_embed - when one backend isn't enough" |
1706 | .IX Subsection "ev_embed - when one backend isn't enough..." |
1277 | This is a rather advanced watcher type that lets you embed one event loop |
1707 | This is a rather advanced watcher type that lets you embed one event loop |
1278 | into another (currently only \f(CW\*(C`ev_io\*(C'\fR events are supported in the embedded |
1708 | into another (currently only \f(CW\*(C`ev_io\*(C'\fR events are supported in the embedded |
1279 | loop, other types of watchers might be handled in a delayed or incorrect |
1709 | loop, other types of watchers might be handled in a delayed or incorrect |
1280 | fashion and must not be used). |
1710 | fashion and must not be used). |
1281 | .PP |
1711 | .PP |
… | |
… | |
1361 | .IP "ev_embed_sweep (loop, ev_embed *)" 4 |
1791 | .IP "ev_embed_sweep (loop, ev_embed *)" 4 |
1362 | .IX Item "ev_embed_sweep (loop, ev_embed *)" |
1792 | .IX Item "ev_embed_sweep (loop, ev_embed *)" |
1363 | Make a single, non-blocking sweep over the embedded loop. This works |
1793 | Make a single, non-blocking sweep over the embedded loop. This works |
1364 | similarly to \f(CW\*(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\*(C'\fR, but in the most |
1794 | similarly to \f(CW\*(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\*(C'\fR, but in the most |
1365 | apropriate way for embedded loops. |
1795 | apropriate way for embedded loops. |
|
|
1796 | .IP "struct ev_loop *loop [read\-only]" 4 |
|
|
1797 | .IX Item "struct ev_loop *loop [read-only]" |
|
|
1798 | The embedded event loop. |
|
|
1799 | .ie n .Sh """ev_fork"" \- the audacity to resume the event loop after a fork" |
|
|
1800 | .el .Sh "\f(CWev_fork\fP \- the audacity to resume the event loop after a fork" |
|
|
1801 | .IX Subsection "ev_fork - the audacity to resume the event loop after a fork" |
|
|
1802 | Fork watchers are called when a \f(CW\*(C`fork ()\*(C'\fR was detected (usually because |
|
|
1803 | whoever is a good citizen cared to tell libev about it by calling |
|
|
1804 | \&\f(CW\*(C`ev_default_fork\*(C'\fR or \f(CW\*(C`ev_loop_fork\*(C'\fR). The invocation is done before the |
|
|
1805 | event loop blocks next and before \f(CW\*(C`ev_check\*(C'\fR watchers are being called, |
|
|
1806 | and only in the child after the fork. If whoever good citizen calling |
|
|
1807 | \&\f(CW\*(C`ev_default_fork\*(C'\fR cheats and calls it in the wrong process, the fork |
|
|
1808 | handlers will be invoked, too, of course. |
|
|
1809 | .IP "ev_fork_init (ev_signal *, callback)" 4 |
|
|
1810 | .IX Item "ev_fork_init (ev_signal *, callback)" |
|
|
1811 | Initialises and configures the fork watcher \- it has no parameters of any |
|
|
1812 | kind. There is a \f(CW\*(C`ev_fork_set\*(C'\fR macro, but using it is utterly pointless, |
|
|
1813 | believe me. |
1366 | .SH "OTHER FUNCTIONS" |
1814 | .SH "OTHER FUNCTIONS" |
1367 | .IX Header "OTHER FUNCTIONS" |
1815 | .IX Header "OTHER FUNCTIONS" |
1368 | There are some other functions of possible interest. Described. Here. Now. |
1816 | There are some other functions of possible interest. Described. Here. Now. |
1369 | .IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4 |
1817 | .IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4 |
1370 | .IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" |
1818 | .IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" |
… | |
… | |
1509 | \&\f(CW\*(C`ev_TYPE_again\*(C'\fR function. |
1957 | \&\f(CW\*(C`ev_TYPE_again\*(C'\fR function. |
1510 | .ie n .IP "w\->sweep () ""ev::embed"" only" 4 |
1958 | .ie n .IP "w\->sweep () ""ev::embed"" only" 4 |
1511 | .el .IP "w\->sweep () \f(CWev::embed\fR only" 4 |
1959 | .el .IP "w\->sweep () \f(CWev::embed\fR only" 4 |
1512 | .IX Item "w->sweep () ev::embed only" |
1960 | .IX Item "w->sweep () ev::embed only" |
1513 | Invokes \f(CW\*(C`ev_embed_sweep\*(C'\fR. |
1961 | Invokes \f(CW\*(C`ev_embed_sweep\*(C'\fR. |
|
|
1962 | .ie n .IP "w\->update () ""ev::stat"" only" 4 |
|
|
1963 | .el .IP "w\->update () \f(CWev::stat\fR only" 4 |
|
|
1964 | .IX Item "w->update () ev::stat only" |
|
|
1965 | Invokes \f(CW\*(C`ev_stat_stat\*(C'\fR. |
1514 | .RE |
1966 | .RE |
1515 | .RS 4 |
1967 | .RS 4 |
1516 | .RE |
1968 | .RE |
1517 | .PP |
1969 | .PP |
1518 | Example: Define a class with an \s-1IO\s0 and idle watcher, start one of them in |
1970 | Example: Define a class with an \s-1IO\s0 and idle watcher, start one of them in |
… | |
… | |
1535 | \& : io (this, &myclass::io_cb), |
1987 | \& : io (this, &myclass::io_cb), |
1536 | \& idle (this, &myclass::idle_cb) |
1988 | \& idle (this, &myclass::idle_cb) |
1537 | \& { |
1989 | \& { |
1538 | \& io.start (fd, ev::READ); |
1990 | \& io.start (fd, ev::READ); |
1539 | \& } |
1991 | \& } |
|
|
1992 | .Ve |
|
|
1993 | .SH "MACRO MAGIC" |
|
|
1994 | .IX Header "MACRO MAGIC" |
|
|
1995 | Libev can be compiled with a variety of options, the most fundemantal is |
|
|
1996 | \&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines wether (most) functions and |
|
|
1997 | callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument. |
|
|
1998 | .PP |
|
|
1999 | To make it easier to write programs that cope with either variant, the |
|
|
2000 | following macros are defined: |
|
|
2001 | .ie n .IP """EV_A""\fR, \f(CW""EV_A_""" 4 |
|
|
2002 | .el .IP "\f(CWEV_A\fR, \f(CWEV_A_\fR" 4 |
|
|
2003 | .IX Item "EV_A, EV_A_" |
|
|
2004 | This provides the loop \fIargument\fR for functions, if one is required (\*(L"ev |
|
|
2005 | loop argument\*(R"). The \f(CW\*(C`EV_A\*(C'\fR form is used when this is the sole argument, |
|
|
2006 | \&\f(CW\*(C`EV_A_\*(C'\fR is used when other arguments are following. Example: |
|
|
2007 | .Sp |
|
|
2008 | .Vb 3 |
|
|
2009 | \& ev_unref (EV_A); |
|
|
2010 | \& ev_timer_add (EV_A_ watcher); |
|
|
2011 | \& ev_loop (EV_A_ 0); |
|
|
2012 | .Ve |
|
|
2013 | .Sp |
|
|
2014 | It assumes the variable \f(CW\*(C`loop\*(C'\fR of type \f(CW\*(C`struct ev_loop *\*(C'\fR is in scope, |
|
|
2015 | which is often provided by the following macro. |
|
|
2016 | .ie n .IP """EV_P""\fR, \f(CW""EV_P_""" 4 |
|
|
2017 | .el .IP "\f(CWEV_P\fR, \f(CWEV_P_\fR" 4 |
|
|
2018 | .IX Item "EV_P, EV_P_" |
|
|
2019 | This provides the loop \fIparameter\fR for functions, if one is required (\*(L"ev |
|
|
2020 | loop parameter\*(R"). The \f(CW\*(C`EV_P\*(C'\fR form is used when this is the sole parameter, |
|
|
2021 | \&\f(CW\*(C`EV_P_\*(C'\fR is used when other parameters are following. Example: |
|
|
2022 | .Sp |
|
|
2023 | .Vb 2 |
|
|
2024 | \& // this is how ev_unref is being declared |
|
|
2025 | \& static void ev_unref (EV_P); |
|
|
2026 | .Ve |
|
|
2027 | .Sp |
|
|
2028 | .Vb 2 |
|
|
2029 | \& // this is how you can declare your typical callback |
|
|
2030 | \& static void cb (EV_P_ ev_timer *w, int revents) |
|
|
2031 | .Ve |
|
|
2032 | .Sp |
|
|
2033 | It declares a parameter \f(CW\*(C`loop\*(C'\fR of type \f(CW\*(C`struct ev_loop *\*(C'\fR, quite |
|
|
2034 | suitable for use with \f(CW\*(C`EV_A\*(C'\fR. |
|
|
2035 | .ie n .IP """EV_DEFAULT""\fR, \f(CW""EV_DEFAULT_""" 4 |
|
|
2036 | .el .IP "\f(CWEV_DEFAULT\fR, \f(CWEV_DEFAULT_\fR" 4 |
|
|
2037 | .IX Item "EV_DEFAULT, EV_DEFAULT_" |
|
|
2038 | Similar to the other two macros, this gives you the value of the default |
|
|
2039 | loop, if multiple loops are supported (\*(L"ev loop default\*(R"). |
|
|
2040 | .PP |
|
|
2041 | Example: Declare and initialise a check watcher, utilising the above |
|
|
2042 | macros so it will work regardless of wether multiple loops are supported |
|
|
2043 | or not. |
|
|
2044 | .PP |
|
|
2045 | .Vb 5 |
|
|
2046 | \& static void |
|
|
2047 | \& check_cb (EV_P_ ev_timer *w, int revents) |
|
|
2048 | \& { |
|
|
2049 | \& ev_check_stop (EV_A_ w); |
|
|
2050 | \& } |
|
|
2051 | .Ve |
|
|
2052 | .PP |
|
|
2053 | .Vb 4 |
|
|
2054 | \& ev_check check; |
|
|
2055 | \& ev_check_init (&check, check_cb); |
|
|
2056 | \& ev_check_start (EV_DEFAULT_ &check); |
|
|
2057 | \& ev_loop (EV_DEFAULT_ 0); |
1540 | .Ve |
2058 | .Ve |
1541 | .SH "EMBEDDING" |
2059 | .SH "EMBEDDING" |
1542 | .IX Header "EMBEDDING" |
2060 | .IX Header "EMBEDDING" |
1543 | Libev can (and often is) directly embedded into host |
2061 | Libev can (and often is) directly embedded into host |
1544 | applications. Examples of applications that embed it include the Deliantra |
2062 | applications. Examples of applications that embed it include the Deliantra |
… | |
… | |
1593 | .Vb 1 |
2111 | .Vb 1 |
1594 | \& ev_win32.c required on win32 platforms only |
2112 | \& ev_win32.c required on win32 platforms only |
1595 | .Ve |
2113 | .Ve |
1596 | .PP |
2114 | .PP |
1597 | .Vb 5 |
2115 | .Vb 5 |
1598 | \& ev_select.c only when select backend is enabled (which is is by default) |
2116 | \& ev_select.c only when select backend is enabled (which is enabled by default) |
1599 | \& ev_poll.c only when poll backend is enabled (disabled by default) |
2117 | \& ev_poll.c only when poll backend is enabled (disabled by default) |
1600 | \& ev_epoll.c only when the epoll backend is enabled (disabled by default) |
2118 | \& ev_epoll.c only when the epoll backend is enabled (disabled by default) |
1601 | \& ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
2119 | \& ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
1602 | \& ev_port.c only when the solaris port backend is enabled (disabled by default) |
2120 | \& ev_port.c only when the solaris port backend is enabled (disabled by default) |
1603 | .Ve |
2121 | .Ve |
1604 | .PP |
2122 | .PP |
1605 | \&\fIev.c\fR includes the backend files directly when enabled, so you only need |
2123 | \&\fIev.c\fR includes the backend files directly when enabled, so you only need |
1606 | to compile a single file. |
2124 | to compile this single file. |
1607 | .PP |
2125 | .PP |
1608 | \fI\s-1LIBEVENT\s0 \s-1COMPATIBILITY\s0 \s-1API\s0\fR |
2126 | \fI\s-1LIBEVENT\s0 \s-1COMPATIBILITY\s0 \s-1API\s0\fR |
1609 | .IX Subsection "LIBEVENT COMPATIBILITY API" |
2127 | .IX Subsection "LIBEVENT COMPATIBILITY API" |
1610 | .PP |
2128 | .PP |
1611 | To include the libevent compatibility \s-1API\s0, also include: |
2129 | To include the libevent compatibility \s-1API\s0, also include: |
… | |
… | |
1632 | \fI\s-1AUTOCONF\s0 \s-1SUPPORT\s0\fR |
2150 | \fI\s-1AUTOCONF\s0 \s-1SUPPORT\s0\fR |
1633 | .IX Subsection "AUTOCONF SUPPORT" |
2151 | .IX Subsection "AUTOCONF SUPPORT" |
1634 | .PP |
2152 | .PP |
1635 | Instead of using \f(CW\*(C`EV_STANDALONE=1\*(C'\fR and providing your config in |
2153 | Instead of using \f(CW\*(C`EV_STANDALONE=1\*(C'\fR and providing your config in |
1636 | whatever way you want, you can also \f(CW\*(C`m4_include([libev.m4])\*(C'\fR in your |
2154 | whatever way you want, you can also \f(CW\*(C`m4_include([libev.m4])\*(C'\fR in your |
1637 | \&\fIconfigure.ac\fR and leave \f(CW\*(C`EV_STANDALONE\*(C'\fR off. \fIev.c\fR will then include |
2155 | \&\fIconfigure.ac\fR and leave \f(CW\*(C`EV_STANDALONE\*(C'\fR undefined. \fIev.c\fR will then |
1638 | \&\fIconfig.h\fR and configure itself accordingly. |
2156 | include \fIconfig.h\fR and configure itself accordingly. |
1639 | .PP |
2157 | .PP |
1640 | For this of course you need the m4 file: |
2158 | For this of course you need the m4 file: |
1641 | .PP |
2159 | .PP |
1642 | .Vb 1 |
2160 | .Vb 1 |
1643 | \& libev.m4 |
2161 | \& libev.m4 |
… | |
… | |
1724 | otherwise another method will be used as fallback. This is the preferred |
2242 | otherwise another method will be used as fallback. This is the preferred |
1725 | backend for Solaris 10 systems. |
2243 | backend for Solaris 10 systems. |
1726 | .IP "\s-1EV_USE_DEVPOLL\s0" 4 |
2244 | .IP "\s-1EV_USE_DEVPOLL\s0" 4 |
1727 | .IX Item "EV_USE_DEVPOLL" |
2245 | .IX Item "EV_USE_DEVPOLL" |
1728 | reserved for future expansion, works like the \s-1USE\s0 symbols above. |
2246 | reserved for future expansion, works like the \s-1USE\s0 symbols above. |
|
|
2247 | .IP "\s-1EV_USE_INOTIFY\s0" 4 |
|
|
2248 | .IX Item "EV_USE_INOTIFY" |
|
|
2249 | If defined to be \f(CW1\fR, libev will compile in support for the Linux inotify |
|
|
2250 | interface to speed up \f(CW\*(C`ev_stat\*(C'\fR watchers. Its actual availability will |
|
|
2251 | be detected at runtime. |
1729 | .IP "\s-1EV_H\s0" 4 |
2252 | .IP "\s-1EV_H\s0" 4 |
1730 | .IX Item "EV_H" |
2253 | .IX Item "EV_H" |
1731 | The name of the \fIev.h\fR header file used to include it. The default if |
2254 | The name of the \fIev.h\fR header file used to include it. The default if |
1732 | undefined is \f(CW\*(C`<ev.h>\*(C'\fR in \fIevent.h\fR and \f(CW"ev.h"\fR in \fIev.c\fR. This |
2255 | undefined is \f(CW\*(C`<ev.h>\*(C'\fR in \fIevent.h\fR and \f(CW"ev.h"\fR in \fIev.c\fR. This |
1733 | can be used to virtually rename the \fIev.h\fR header file in case of conflicts. |
2256 | can be used to virtually rename the \fIev.h\fR header file in case of conflicts. |
… | |
… | |
1751 | If undefined or defined to \f(CW1\fR, then all event-loop-specific functions |
2274 | If undefined or defined to \f(CW1\fR, then all event-loop-specific functions |
1752 | will have the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument, and you can create |
2275 | will have the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument, and you can create |
1753 | additional independent event loops. Otherwise there will be no support |
2276 | additional independent event loops. Otherwise there will be no support |
1754 | for multiple event loops and there is no first event loop pointer |
2277 | for multiple event loops and there is no first event loop pointer |
1755 | argument. Instead, all functions act on the single default loop. |
2278 | argument. Instead, all functions act on the single default loop. |
1756 | .IP "\s-1EV_PERIODICS\s0" 4 |
2279 | .IP "\s-1EV_PERIODIC_ENABLE\s0" 4 |
1757 | .IX Item "EV_PERIODICS" |
2280 | .IX Item "EV_PERIODIC_ENABLE" |
1758 | If undefined or defined to be \f(CW1\fR, then periodic timers are supported, |
2281 | If undefined or defined to be \f(CW1\fR, then periodic timers are supported. If |
1759 | otherwise not. This saves a few kb of code. |
2282 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
|
|
2283 | code. |
|
|
2284 | .IP "\s-1EV_IDLE_ENABLE\s0" 4 |
|
|
2285 | .IX Item "EV_IDLE_ENABLE" |
|
|
2286 | If undefined or defined to be \f(CW1\fR, then idle watchers are supported. If |
|
|
2287 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
|
|
2288 | code. |
|
|
2289 | .IP "\s-1EV_EMBED_ENABLE\s0" 4 |
|
|
2290 | .IX Item "EV_EMBED_ENABLE" |
|
|
2291 | If undefined or defined to be \f(CW1\fR, then embed watchers are supported. If |
|
|
2292 | defined to be \f(CW0\fR, then they are not. |
|
|
2293 | .IP "\s-1EV_STAT_ENABLE\s0" 4 |
|
|
2294 | .IX Item "EV_STAT_ENABLE" |
|
|
2295 | If undefined or defined to be \f(CW1\fR, then stat watchers are supported. If |
|
|
2296 | defined to be \f(CW0\fR, then they are not. |
|
|
2297 | .IP "\s-1EV_FORK_ENABLE\s0" 4 |
|
|
2298 | .IX Item "EV_FORK_ENABLE" |
|
|
2299 | If undefined or defined to be \f(CW1\fR, then fork watchers are supported. If |
|
|
2300 | defined to be \f(CW0\fR, then they are not. |
|
|
2301 | .IP "\s-1EV_MINIMAL\s0" 4 |
|
|
2302 | .IX Item "EV_MINIMAL" |
|
|
2303 | If you need to shave off some kilobytes of code at the expense of some |
|
|
2304 | speed, define this symbol to \f(CW1\fR. Currently only used for gcc to override |
|
|
2305 | some inlining decisions, saves roughly 30% codesize of amd64. |
|
|
2306 | .IP "\s-1EV_PID_HASHSIZE\s0" 4 |
|
|
2307 | .IX Item "EV_PID_HASHSIZE" |
|
|
2308 | \&\f(CW\*(C`ev_child\*(C'\fR watchers use a small hash table to distribute workload by |
|
|
2309 | pid. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), usually more |
|
|
2310 | than enough. If you need to manage thousands of children you might want to |
|
|
2311 | increase this value (\fImust\fR be a power of two). |
|
|
2312 | .IP "\s-1EV_INOTIFY_HASHSIZE\s0" 4 |
|
|
2313 | .IX Item "EV_INOTIFY_HASHSIZE" |
|
|
2314 | \&\f(CW\*(C`ev_staz\*(C'\fR watchers use a small hash table to distribute workload by |
|
|
2315 | inotify watch id. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), |
|
|
2316 | usually more than enough. If you need to manage thousands of \f(CW\*(C`ev_stat\*(C'\fR |
|
|
2317 | watchers you might want to increase this value (\fImust\fR be a power of |
|
|
2318 | two). |
1760 | .IP "\s-1EV_COMMON\s0" 4 |
2319 | .IP "\s-1EV_COMMON\s0" 4 |
1761 | .IX Item "EV_COMMON" |
2320 | .IX Item "EV_COMMON" |
1762 | By default, all watchers have a \f(CW\*(C`void *data\*(C'\fR member. By redefining |
2321 | By default, all watchers have a \f(CW\*(C`void *data\*(C'\fR member. By redefining |
1763 | this macro to a something else you can include more and other types of |
2322 | this macro to a something else you can include more and other types of |
1764 | members. You have to define it each time you include one of the files, |
2323 | members. You have to define it each time you include one of the files, |
… | |
… | |
1769 | .Vb 3 |
2328 | .Vb 3 |
1770 | \& #define EV_COMMON \e |
2329 | \& #define EV_COMMON \e |
1771 | \& SV *self; /* contains this struct */ \e |
2330 | \& SV *self; /* contains this struct */ \e |
1772 | \& SV *cb_sv, *fh /* note no trailing ";" */ |
2331 | \& SV *cb_sv, *fh /* note no trailing ";" */ |
1773 | .Ve |
2332 | .Ve |
1774 | .IP "\s-1EV_CB_DECLARE\s0(type)" 4 |
2333 | .IP "\s-1EV_CB_DECLARE\s0 (type)" 4 |
1775 | .IX Item "EV_CB_DECLARE(type)" |
2334 | .IX Item "EV_CB_DECLARE (type)" |
1776 | .PD 0 |
2335 | .PD 0 |
1777 | .IP "\s-1EV_CB_INVOKE\s0(watcher,revents)" 4 |
2336 | .IP "\s-1EV_CB_INVOKE\s0 (watcher, revents)" 4 |
1778 | .IX Item "EV_CB_INVOKE(watcher,revents)" |
2337 | .IX Item "EV_CB_INVOKE (watcher, revents)" |
1779 | .IP "ev_set_cb(ev,cb)" 4 |
2338 | .IP "ev_set_cb (ev, cb)" 4 |
1780 | .IX Item "ev_set_cb(ev,cb)" |
2339 | .IX Item "ev_set_cb (ev, cb)" |
1781 | .PD |
2340 | .PD |
1782 | Can be used to change the callback member declaration in each watcher, |
2341 | Can be used to change the callback member declaration in each watcher, |
1783 | and the way callbacks are invoked and set. Must expand to a struct member |
2342 | and the way callbacks are invoked and set. Must expand to a struct member |
1784 | definition and a statement, respectively. See the \fIev.v\fR header file for |
2343 | definition and a statement, respectively. See the \fIev.v\fR header file for |
1785 | their default definitions. One possible use for overriding these is to |
2344 | their default definitions. One possible use for overriding these is to |
1786 | avoid the ev_loop pointer as first argument in all cases, or to use method |
2345 | avoid the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument in all cases, or to use |
1787 | calls instead of plain function calls in \*(C+. |
2346 | method calls instead of plain function calls in \*(C+. |
1788 | .Sh "\s-1EXAMPLES\s0" |
2347 | .Sh "\s-1EXAMPLES\s0" |
1789 | .IX Subsection "EXAMPLES" |
2348 | .IX Subsection "EXAMPLES" |
1790 | For a real-world example of a program the includes libev |
2349 | For a real-world example of a program the includes libev |
1791 | verbatim, you can have a look at the \s-1EV\s0 perl module |
2350 | verbatim, you can have a look at the \s-1EV\s0 perl module |
1792 | (<http://software.schmorp.de/pkg/EV.html>). It has the libev files in |
2351 | (<http://software.schmorp.de/pkg/EV.html>). It has the libev files in |
… | |
… | |
1794 | interface) and \fI\s-1EV\s0.xs\fR (implementation) files. Only the \fI\s-1EV\s0.xs\fR file |
2353 | interface) and \fI\s-1EV\s0.xs\fR (implementation) files. Only the \fI\s-1EV\s0.xs\fR file |
1795 | will be compiled. It is pretty complex because it provides its own header |
2354 | will be compiled. It is pretty complex because it provides its own header |
1796 | file. |
2355 | file. |
1797 | .Sp |
2356 | .Sp |
1798 | The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file |
2357 | The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file |
1799 | that everybody includes and which overrides some autoconf choices: |
2358 | that everybody includes and which overrides some configure choices: |
1800 | .Sp |
2359 | .Sp |
1801 | .Vb 4 |
2360 | .Vb 9 |
|
|
2361 | \& #define EV_MINIMAL 1 |
1802 | \& #define EV_USE_POLL 0 |
2362 | \& #define EV_USE_POLL 0 |
1803 | \& #define EV_MULTIPLICITY 0 |
2363 | \& #define EV_MULTIPLICITY 0 |
1804 | \& #define EV_PERIODICS 0 |
2364 | \& #define EV_PERIODIC_ENABLE 0 |
|
|
2365 | \& #define EV_STAT_ENABLE 0 |
|
|
2366 | \& #define EV_FORK_ENABLE 0 |
1805 | \& #define EV_CONFIG_H <config.h> |
2367 | \& #define EV_CONFIG_H <config.h> |
|
|
2368 | \& #define EV_MINPRI 0 |
|
|
2369 | \& #define EV_MAXPRI 0 |
1806 | .Ve |
2370 | .Ve |
1807 | .Sp |
2371 | .Sp |
1808 | .Vb 1 |
2372 | .Vb 1 |
1809 | \& #include "ev++.h" |
2373 | \& #include "ev++.h" |
1810 | .Ve |
2374 | .Ve |
… | |
… | |
1813 | .Sp |
2377 | .Sp |
1814 | .Vb 2 |
2378 | .Vb 2 |
1815 | \& #include "ev_cpp.h" |
2379 | \& #include "ev_cpp.h" |
1816 | \& #include "ev.c" |
2380 | \& #include "ev.c" |
1817 | .Ve |
2381 | .Ve |
|
|
2382 | .SH "COMPLEXITIES" |
|
|
2383 | .IX Header "COMPLEXITIES" |
|
|
2384 | In this section the complexities of (many of) the algorithms used inside |
|
|
2385 | libev will be explained. For complexity discussions about backends see the |
|
|
2386 | documentation for \f(CW\*(C`ev_default_init\*(C'\fR. |
|
|
2387 | .RS 4 |
|
|
2388 | .IP "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" 4 |
|
|
2389 | .IX Item "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" |
|
|
2390 | .PD 0 |
|
|
2391 | .IP "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" 4 |
|
|
2392 | .IX Item "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" |
|
|
2393 | .IP "Starting io/check/prepare/idle/signal/child watchers: O(1)" 4 |
|
|
2394 | .IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)" |
|
|
2395 | .IP "Stopping check/prepare/idle watchers: O(1)" 4 |
|
|
2396 | .IX Item "Stopping check/prepare/idle watchers: O(1)" |
|
|
2397 | .IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % \s-1EV_PID_HASHSIZE\s0))" 4 |
|
|
2398 | .IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))" |
|
|
2399 | .IP "Finding the next timer per loop iteration: O(1)" 4 |
|
|
2400 | .IX Item "Finding the next timer per loop iteration: O(1)" |
|
|
2401 | .IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4 |
|
|
2402 | .IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" |
|
|
2403 | .IP "Activating one watcher: O(1)" 4 |
|
|
2404 | .IX Item "Activating one watcher: O(1)" |
|
|
2405 | .RE |
|
|
2406 | .RS 4 |
|
|
2407 | .PD |
1818 | .SH "AUTHOR" |
2408 | .SH "AUTHOR" |
1819 | .IX Header "AUTHOR" |
2409 | .IX Header "AUTHOR" |
1820 | Marc Lehmann <libev@schmorp.de>. |
2410 | Marc Lehmann <libev@schmorp.de>. |