… | |
… | |
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 "2007-12-12" "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" |
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201 | The newest version of this document is also available as a html-formatted |
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202 | web page you might find easier to navigate when reading it for the first |
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203 | time: <http://cvs.schmorp.de/libev/ev.html>. |
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204 | .PP |
142 | Libev is an event loop: you register interest in certain events (such as a |
205 | 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 |
206 | file descriptor being readable or a timeout occuring), and it will manage |
144 | these event sources and provide your program with events. |
207 | these event sources and provide your program with events. |
145 | .PP |
208 | .PP |
146 | To do this, it must take more or less complete control over your process |
209 | To do this, it must take more or less complete control over your process |
… | |
… | |
151 | watchers\fR, which are relatively small C structures you initialise with the |
214 | 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 |
215 | details of the event, and then hand it over to libev by \fIstarting\fR the |
153 | watcher. |
216 | watcher. |
154 | .SH "FEATURES" |
217 | .SH "FEATURES" |
155 | .IX Header "FEATURES" |
218 | .IX Header "FEATURES" |
156 | Libev supports select, poll, the linux-specific epoll and the bsd-specific |
219 | 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 |
220 | 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 |
221 | 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 |
222 | (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 |
223 | with customised rescheduling (\f(CW\*(C`ev_periodic\*(C'\fR), synchronous signals |
161 | fast (see this benchmark comparing |
224 | (\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). |
225 | watchers dealing with the event loop mechanism itself (\f(CW\*(C`ev_idle\*(C'\fR, |
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226 | \&\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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227 | file watchers (\f(CW\*(C`ev_stat\*(C'\fR) and even limited support for fork events |
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228 | (\f(CW\*(C`ev_fork\*(C'\fR). |
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229 | .PP |
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230 | It also is quite fast (see this |
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231 | benchmark comparing it to libevent |
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232 | for example). |
163 | .SH "CONVENTIONS" |
233 | .SH "CONVENTIONS" |
164 | .IX Header "CONVENTIONS" |
234 | .IX Header "CONVENTIONS" |
165 | Libev is very configurable. In this manual the default configuration |
235 | Libev is very configurable. In this manual the default configuration will |
166 | will be described, which supports multiple event loops. For more info |
236 | be described, which supports multiple event loops. For more info about |
167 | about various configuration options please have a look at the file |
237 | 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 |
238 | this manual. If libev was configured without support for multiple event |
169 | support for multiple event loops, then all functions taking an initial |
239 | 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) |
240 | (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" |
241 | .SH "TIME REPRESENTATION" |
173 | .IX Header "TIME REPRESENTATION" |
242 | .IX Header "TIME REPRESENTATION" |
174 | Libev represents time as a single floating point number, representing the |
243 | Libev represents time as a single floating point number, representing the |
175 | (fractional) number of seconds since the (\s-1POSIX\s0) epoch (somewhere near |
244 | (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 |
245 | the beginning of 1970, details are complicated, don't ask). This type is |
… | |
… | |
190 | .IX Item "int ev_version_major ()" |
259 | .IX Item "int ev_version_major ()" |
191 | .PD 0 |
260 | .PD 0 |
192 | .IP "int ev_version_minor ()" 4 |
261 | .IP "int ev_version_minor ()" 4 |
193 | .IX Item "int ev_version_minor ()" |
262 | .IX Item "int ev_version_minor ()" |
194 | .PD |
263 | .PD |
195 | You can find out the major and minor version numbers of the library |
264 | You can find out the major and minor \s-1ABI\s0 version numbers of the library |
196 | you linked against by calling the functions \f(CW\*(C`ev_version_major\*(C'\fR and |
265 | you linked against by calling the functions \f(CW\*(C`ev_version_major\*(C'\fR and |
197 | \&\f(CW\*(C`ev_version_minor\*(C'\fR. If you want, you can compare against the global |
266 | \&\f(CW\*(C`ev_version_minor\*(C'\fR. If you want, you can compare against the global |
198 | symbols \f(CW\*(C`EV_VERSION_MAJOR\*(C'\fR and \f(CW\*(C`EV_VERSION_MINOR\*(C'\fR, which specify the |
267 | symbols \f(CW\*(C`EV_VERSION_MAJOR\*(C'\fR and \f(CW\*(C`EV_VERSION_MINOR\*(C'\fR, which specify the |
199 | version of the library your program was compiled against. |
268 | version of the library your program was compiled against. |
200 | .Sp |
269 | .Sp |
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270 | These version numbers refer to the \s-1ABI\s0 version of the library, not the |
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271 | release version. |
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272 | .Sp |
201 | Usually, it's a good idea to terminate if the major versions mismatch, |
273 | Usually, it's a good idea to terminate if the major versions mismatch, |
202 | as this indicates an incompatible change. Minor versions are usually |
274 | as this indicates an incompatible change. Minor versions are usually |
203 | compatible to older versions, so a larger minor version alone is usually |
275 | compatible to older versions, so a larger minor version alone is usually |
204 | not a problem. |
276 | not a problem. |
205 | .Sp |
277 | .Sp |
206 | Example: make sure we haven't accidentally been linked against the wrong |
278 | Example: Make sure we haven't accidentally been linked against the wrong |
207 | version: |
279 | version. |
208 | .Sp |
280 | .Sp |
209 | .Vb 3 |
281 | .Vb 3 |
210 | \& assert (("libev version mismatch", |
282 | \& assert (("libev version mismatch", |
211 | \& ev_version_major () == EV_VERSION_MAJOR |
283 | \& ev_version_major () == EV_VERSION_MAJOR |
212 | \& && ev_version_minor () >= EV_VERSION_MINOR)); |
284 | \& && ev_version_minor () >= EV_VERSION_MINOR)); |
… | |
… | |
242 | recommended ones. |
314 | recommended ones. |
243 | .Sp |
315 | .Sp |
244 | See the description of \f(CW\*(C`ev_embed\*(C'\fR watchers for more info. |
316 | 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 |
317 | .IP "ev_set_allocator (void *(*cb)(void *ptr, long size))" 4 |
246 | .IX Item "ev_set_allocator (void *(*cb)(void *ptr, long size))" |
318 | .IX Item "ev_set_allocator (void *(*cb)(void *ptr, long size))" |
247 | Sets the allocation function to use (the prototype is similar to the |
319 | Sets the allocation function to use (the prototype is similar \- the |
248 | realloc C function, the semantics are identical). It is used to allocate |
320 | 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 |
321 | 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 |
322 | memory needs to be allocated, the library might abort or take some |
251 | destructive action. The default is your system realloc function. |
323 | potentially destructive action. The default is your system realloc |
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324 | function. |
252 | .Sp |
325 | .Sp |
253 | You could override this function in high-availability programs to, say, |
326 | 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, |
327 | 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. |
328 | or even to sleep a while and retry until some memory is available. |
256 | .Sp |
329 | .Sp |
257 | Example: replace the libev allocator with one that waits a bit and then |
330 | Example: Replace the libev allocator with one that waits a bit and then |
258 | retries: better than mine). |
331 | retries). |
259 | .Sp |
332 | .Sp |
260 | .Vb 6 |
333 | .Vb 6 |
261 | \& static void * |
334 | \& static void * |
262 | \& persistent_realloc (void *ptr, long size) |
335 | \& persistent_realloc (void *ptr, size_t size) |
263 | \& { |
336 | \& { |
264 | \& for (;;) |
337 | \& for (;;) |
265 | \& { |
338 | \& { |
266 | \& void *newptr = realloc (ptr, size); |
339 | \& void *newptr = realloc (ptr, size); |
267 | .Ve |
340 | .Ve |
… | |
… | |
289 | callback is set, then libev will expect it to remedy the sitution, no |
362 | 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 |
363 | 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 |
364 | requested operation, or, if the condition doesn't go away, do bad stuff |
292 | (such as abort). |
365 | (such as abort). |
293 | .Sp |
366 | .Sp |
294 | Example: do the same thing as libev does internally: |
367 | Example: This is basically the same thing that libev does internally, too. |
295 | .Sp |
368 | .Sp |
296 | .Vb 6 |
369 | .Vb 6 |
297 | \& static void |
370 | \& static void |
298 | \& fatal_error (const char *msg) |
371 | \& fatal_error (const char *msg) |
299 | \& { |
372 | \& { |
… | |
… | |
345 | or setgid) then libev will \fInot\fR look at the environment variable |
418 | 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 |
419 | \&\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 |
420 | 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 |
421 | useful to try out specific backends to test their performance, or to work |
349 | around bugs. |
422 | around bugs. |
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423 | .ie n .IP """EVFLAG_FORKCHECK""" 4 |
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424 | .el .IP "\f(CWEVFLAG_FORKCHECK\fR" 4 |
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425 | .IX Item "EVFLAG_FORKCHECK" |
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426 | 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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427 | a fork, you can also make libev check for a fork in each iteration by |
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428 | enabling this flag. |
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429 | .Sp |
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430 | This works by calling \f(CW\*(C`getpid ()\*(C'\fR on every iteration of the loop, |
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431 | and thus this might slow down your event loop if you do a lot of loop |
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432 | iterations and little real work, but is usually not noticeable (on my |
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433 | Linux system for example, \f(CW\*(C`getpid\*(C'\fR is actually a simple 5\-insn sequence |
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434 | without a syscall and thus \fIvery\fR fast, but my Linux system also has |
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435 | \&\f(CW\*(C`pthread_atfork\*(C'\fR which is even faster). |
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436 | .Sp |
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437 | The big advantage of this flag is that you can forget about fork (and |
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438 | forget about forgetting to tell libev about forking) when you use this |
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439 | flag. |
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440 | .Sp |
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441 | This flag setting cannot be overriden or specified in the \f(CW\*(C`LIBEV_FLAGS\*(C'\fR |
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442 | environment variable. |
350 | .ie n .IP """EVBACKEND_SELECT"" (value 1, portable select backend)" 4 |
443 | .ie n .IP """EVBACKEND_SELECT"" (value 1, portable select backend)" 4 |
351 | .el .IP "\f(CWEVBACKEND_SELECT\fR (value 1, portable select backend)" 4 |
444 | .el .IP "\f(CWEVBACKEND_SELECT\fR (value 1, portable select backend)" 4 |
352 | .IX Item "EVBACKEND_SELECT (value 1, portable select backend)" |
445 | .IX Item "EVBACKEND_SELECT (value 1, portable select backend)" |
353 | This is your standard \fIselect\fR\|(2) backend. Not \fIcompletely\fR standard, as |
446 | 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, |
447 | 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 |
541 | 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 |
542 | 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 |
543 | 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). |
544 | undefined behaviour (or a failed assertion if assertions are enabled). |
452 | .Sp |
545 | .Sp |
453 | Example: try to create a event loop that uses epoll and nothing else. |
546 | Example: Try to create a event loop that uses epoll and nothing else. |
454 | .Sp |
547 | .Sp |
455 | .Vb 3 |
548 | .Vb 3 |
456 | \& struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
549 | \& struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
457 | \& if (!epoller) |
550 | \& if (!epoller) |
458 | \& fatal ("no epoll found here, maybe it hides under your chair"); |
551 | \& fatal ("no epoll found here, maybe it hides under your chair"); |
… | |
… | |
495 | .IP "ev_loop_fork (loop)" 4 |
588 | .IP "ev_loop_fork (loop)" 4 |
496 | .IX Item "ev_loop_fork (loop)" |
589 | .IX Item "ev_loop_fork (loop)" |
497 | Like \f(CW\*(C`ev_default_fork\*(C'\fR, but acts on an event loop created by |
590 | 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 |
591 | \&\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. |
592 | after fork, and how you do this is entirely your own problem. |
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593 | .IP "unsigned int ev_loop_count (loop)" 4 |
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594 | .IX Item "unsigned int ev_loop_count (loop)" |
|
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595 | Returns the count of loop iterations for the loop, which is identical to |
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596 | the number of times libev did poll for new events. It starts at \f(CW0\fR and |
|
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597 | happily wraps around with enough iterations. |
|
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598 | .Sp |
|
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599 | This value can sometimes be useful as a generation counter of sorts (it |
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600 | \&\*(L"ticks\*(R" the number of loop iterations), as it roughly corresponds with |
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601 | \&\f(CW\*(C`ev_prepare\*(C'\fR and \f(CW\*(C`ev_check\*(C'\fR calls. |
500 | .IP "unsigned int ev_backend (loop)" 4 |
602 | .IP "unsigned int ev_backend (loop)" 4 |
501 | .IX Item "unsigned int ev_backend (loop)" |
603 | .IX Item "unsigned int ev_backend (loop)" |
502 | Returns one of the \f(CW\*(C`EVBACKEND_*\*(C'\fR flags indicating the event backend in |
604 | Returns one of the \f(CW\*(C`EVBACKEND_*\*(C'\fR flags indicating the event backend in |
503 | use. |
605 | use. |
504 | .IP "ev_tstamp ev_now (loop)" 4 |
606 | .IP "ev_tstamp ev_now (loop)" 4 |
… | |
… | |
535 | libev watchers. However, a pair of \f(CW\*(C`ev_prepare\*(C'\fR/\f(CW\*(C`ev_check\*(C'\fR watchers is |
637 | libev watchers. However, a pair of \f(CW\*(C`ev_prepare\*(C'\fR/\f(CW\*(C`ev_check\*(C'\fR watchers is |
536 | usually a better approach for this kind of thing. |
638 | usually a better approach for this kind of thing. |
537 | .Sp |
639 | .Sp |
538 | Here are the gory details of what \f(CW\*(C`ev_loop\*(C'\fR does: |
640 | Here are the gory details of what \f(CW\*(C`ev_loop\*(C'\fR does: |
539 | .Sp |
641 | .Sp |
540 | .Vb 18 |
642 | .Vb 19 |
|
|
643 | \& - Before the first iteration, call any pending watchers. |
541 | \& * If there are no active watchers (reference count is zero), return. |
644 | \& * If there are no active watchers (reference count is zero), return. |
542 | \& - Queue prepare watchers and then call all outstanding watchers. |
645 | \& - Queue all prepare watchers and then call all outstanding watchers. |
543 | \& - If we have been forked, recreate the kernel state. |
646 | \& - If we have been forked, recreate the kernel state. |
544 | \& - Update the kernel state with all outstanding changes. |
647 | \& - Update the kernel state with all outstanding changes. |
545 | \& - Update the "event loop time". |
648 | \& - Update the "event loop time". |
546 | \& - Calculate for how long to block. |
649 | \& - Calculate for how long to block. |
547 | \& - Block the process, waiting for any events. |
650 | \& - Block the process, waiting for any events. |
… | |
… | |
556 | \& be handled here by queueing them when their watcher gets executed. |
659 | \& be handled here by queueing them when their watcher gets executed. |
557 | \& - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
660 | \& - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
558 | \& were used, return, otherwise continue with step *. |
661 | \& were used, return, otherwise continue with step *. |
559 | .Ve |
662 | .Ve |
560 | .Sp |
663 | .Sp |
561 | Example: queue some jobs and then loop until no events are outsanding |
664 | Example: Queue some jobs and then loop until no events are outsanding |
562 | anymore. |
665 | anymore. |
563 | .Sp |
666 | .Sp |
564 | .Vb 4 |
667 | .Vb 4 |
565 | \& ... queue jobs here, make sure they register event watchers as long |
668 | \& ... 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..) |
669 | \& ... 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 |
691 | 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 |
692 | 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 |
693 | 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. |
694 | libraries. Just remember to \fIunref after start\fR and \fIref before stop\fR. |
592 | .Sp |
695 | .Sp |
593 | Example: create a signal watcher, but keep it from keeping \f(CW\*(C`ev_loop\*(C'\fR |
696 | Example: Create a signal watcher, but keep it from keeping \f(CW\*(C`ev_loop\*(C'\fR |
594 | running when nothing else is active. |
697 | running when nothing else is active. |
595 | .Sp |
698 | .Sp |
596 | .Vb 4 |
699 | .Vb 4 |
597 | \& struct dv_signal exitsig; |
700 | \& struct ev_signal exitsig; |
598 | \& ev_signal_init (&exitsig, sig_cb, SIGINT); |
701 | \& ev_signal_init (&exitsig, sig_cb, SIGINT); |
599 | \& ev_signal_start (myloop, &exitsig); |
702 | \& ev_signal_start (loop, &exitsig); |
600 | \& evf_unref (myloop); |
703 | \& evf_unref (loop); |
601 | .Ve |
704 | .Ve |
602 | .Sp |
705 | .Sp |
603 | Example: for some weird reason, unregister the above signal handler again. |
706 | Example: For some weird reason, unregister the above signal handler again. |
604 | .Sp |
707 | .Sp |
605 | .Vb 2 |
708 | .Vb 2 |
606 | \& ev_ref (myloop); |
709 | \& ev_ref (loop); |
607 | \& ev_signal_stop (myloop, &exitsig); |
710 | \& ev_signal_stop (loop, &exitsig); |
608 | .Ve |
711 | .Ve |
609 | .SH "ANATOMY OF A WATCHER" |
712 | .SH "ANATOMY OF A WATCHER" |
610 | .IX Header "ANATOMY OF A WATCHER" |
713 | .IX Header "ANATOMY OF A WATCHER" |
611 | A watcher is a structure that you create and register to record your |
714 | 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 |
715 | 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. |
787 | 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 |
788 | .ie n .IP """EV_CHILD""" 4 |
686 | .el .IP "\f(CWEV_CHILD\fR" 4 |
789 | .el .IP "\f(CWEV_CHILD\fR" 4 |
687 | .IX Item "EV_CHILD" |
790 | .IX Item "EV_CHILD" |
688 | The pid specified in the \f(CW\*(C`ev_child\*(C'\fR watcher has received a status change. |
791 | The pid specified in the \f(CW\*(C`ev_child\*(C'\fR watcher has received a status change. |
|
|
792 | .ie n .IP """EV_STAT""" 4 |
|
|
793 | .el .IP "\f(CWEV_STAT\fR" 4 |
|
|
794 | .IX Item "EV_STAT" |
|
|
795 | The path specified in the \f(CW\*(C`ev_stat\*(C'\fR watcher changed its attributes somehow. |
689 | .ie n .IP """EV_IDLE""" 4 |
796 | .ie n .IP """EV_IDLE""" 4 |
690 | .el .IP "\f(CWEV_IDLE\fR" 4 |
797 | .el .IP "\f(CWEV_IDLE\fR" 4 |
691 | .IX Item "EV_IDLE" |
798 | .IX Item "EV_IDLE" |
692 | The \f(CW\*(C`ev_idle\*(C'\fR watcher has determined that you have nothing better to do. |
799 | 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 |
800 | .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 |
810 | \&\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 |
811 | 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 |
812 | 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 |
813 | (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). |
814 | \&\f(CW\*(C`ev_loop\*(C'\fR from blocking). |
|
|
815 | .ie n .IP """EV_EMBED""" 4 |
|
|
816 | .el .IP "\f(CWEV_EMBED\fR" 4 |
|
|
817 | .IX Item "EV_EMBED" |
|
|
818 | The embedded event loop specified in the \f(CW\*(C`ev_embed\*(C'\fR watcher needs attention. |
|
|
819 | .ie n .IP """EV_FORK""" 4 |
|
|
820 | .el .IP "\f(CWEV_FORK\fR" 4 |
|
|
821 | .IX Item "EV_FORK" |
|
|
822 | The event loop has been resumed in the child process after fork (see |
|
|
823 | \&\f(CW\*(C`ev_fork\*(C'\fR). |
708 | .ie n .IP """EV_ERROR""" 4 |
824 | .ie n .IP """EV_ERROR""" 4 |
709 | .el .IP "\f(CWEV_ERROR\fR" 4 |
825 | .el .IP "\f(CWEV_ERROR\fR" 4 |
710 | .IX Item "EV_ERROR" |
826 | .IX Item "EV_ERROR" |
711 | An unspecified error has occured, the watcher has been stopped. This might |
827 | An unspecified error has occured, the watcher has been stopped. This might |
712 | happen because the watcher could not be properly started because libev |
828 | happen because the watcher could not be properly started because libev |
… | |
… | |
777 | .IP "bool ev_is_pending (ev_TYPE *watcher)" 4 |
893 | .IP "bool ev_is_pending (ev_TYPE *watcher)" 4 |
778 | .IX Item "bool ev_is_pending (ev_TYPE *watcher)" |
894 | .IX Item "bool ev_is_pending (ev_TYPE *watcher)" |
779 | Returns a true value iff the watcher is pending, (i.e. it has outstanding |
895 | 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 |
896 | 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 |
897 | 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 |
898 | \&\f(CW\*(C`ev_TYPE_set\*(C'\fR is safe), you must not change its priority, and you must |
783 | libev (e.g. you cnanot \f(CW\*(C`free ()\*(C'\fR it). |
899 | make sure the watcher is available to libev (e.g. you cannot \f(CW\*(C`free ()\*(C'\fR |
|
|
900 | it). |
784 | .IP "callback = ev_cb (ev_TYPE *watcher)" 4 |
901 | .IP "callback ev_cb (ev_TYPE *watcher)" 4 |
785 | .IX Item "callback = ev_cb (ev_TYPE *watcher)" |
902 | .IX Item "callback ev_cb (ev_TYPE *watcher)" |
786 | Returns the callback currently set on the watcher. |
903 | Returns the callback currently set on the watcher. |
787 | .IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 |
904 | .IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 |
788 | .IX Item "ev_cb_set (ev_TYPE *watcher, callback)" |
905 | .IX Item "ev_cb_set (ev_TYPE *watcher, callback)" |
789 | Change the callback. You can change the callback at virtually any time |
906 | Change the callback. You can change the callback at virtually any time |
790 | (modulo threads). |
907 | (modulo threads). |
|
|
908 | .IP "ev_set_priority (ev_TYPE *watcher, priority)" 4 |
|
|
909 | .IX Item "ev_set_priority (ev_TYPE *watcher, priority)" |
|
|
910 | .PD 0 |
|
|
911 | .IP "int ev_priority (ev_TYPE *watcher)" 4 |
|
|
912 | .IX Item "int ev_priority (ev_TYPE *watcher)" |
|
|
913 | .PD |
|
|
914 | Set and query the priority of the watcher. The priority is a small |
|
|
915 | integer between \f(CW\*(C`EV_MAXPRI\*(C'\fR (default: \f(CW2\fR) and \f(CW\*(C`EV_MINPRI\*(C'\fR |
|
|
916 | (default: \f(CW\*(C`\-2\*(C'\fR). Pending watchers with higher priority will be invoked |
|
|
917 | before watchers with lower priority, but priority will not keep watchers |
|
|
918 | from being executed (except for \f(CW\*(C`ev_idle\*(C'\fR watchers). |
|
|
919 | .Sp |
|
|
920 | This means that priorities are \fIonly\fR used for ordering callback |
|
|
921 | invocation after new events have been received. This is useful, for |
|
|
922 | example, to reduce latency after idling, or more often, to bind two |
|
|
923 | watchers on the same event and make sure one is called first. |
|
|
924 | .Sp |
|
|
925 | If you need to suppress invocation when higher priority events are pending |
|
|
926 | you need to look at \f(CW\*(C`ev_idle\*(C'\fR watchers, which provide this functionality. |
|
|
927 | .Sp |
|
|
928 | You \fImust not\fR change the priority of a watcher as long as it is active or |
|
|
929 | pending. |
|
|
930 | .Sp |
|
|
931 | The default priority used by watchers when no priority has been set is |
|
|
932 | always \f(CW0\fR, which is supposed to not be too high and not be too low :). |
|
|
933 | .Sp |
|
|
934 | Setting a priority outside the range of \f(CW\*(C`EV_MINPRI\*(C'\fR to \f(CW\*(C`EV_MAXPRI\*(C'\fR is |
|
|
935 | fine, as long as you do not mind that the priority value you query might |
|
|
936 | or might not have been adjusted to be within valid range. |
|
|
937 | .IP "ev_invoke (loop, ev_TYPE *watcher, int revents)" 4 |
|
|
938 | .IX Item "ev_invoke (loop, ev_TYPE *watcher, int revents)" |
|
|
939 | Invoke the \f(CW\*(C`watcher\*(C'\fR with the given \f(CW\*(C`loop\*(C'\fR and \f(CW\*(C`revents\*(C'\fR. Neither |
|
|
940 | \&\f(CW\*(C`loop\*(C'\fR nor \f(CW\*(C`revents\*(C'\fR need to be valid as long as the watcher callback |
|
|
941 | can deal with that fact. |
|
|
942 | .IP "int ev_clear_pending (loop, ev_TYPE *watcher)" 4 |
|
|
943 | .IX Item "int ev_clear_pending (loop, ev_TYPE *watcher)" |
|
|
944 | If the watcher is pending, this function returns clears its pending status |
|
|
945 | and returns its \f(CW\*(C`revents\*(C'\fR bitset (as if its callback was invoked). If the |
|
|
946 | watcher isn't pending it does nothing and returns \f(CW0\fR. |
791 | .Sh "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0" |
947 | .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" |
948 | .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 |
949 | 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 |
950 | 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 |
951 | to associate arbitrary data with your watcher. If you need more data and |
… | |
… | |
816 | \& struct my_io *w = (struct my_io *)w_; |
972 | \& struct my_io *w = (struct my_io *)w_; |
817 | \& ... |
973 | \& ... |
818 | \& } |
974 | \& } |
819 | .Ve |
975 | .Ve |
820 | .PP |
976 | .PP |
821 | More interesting and less C\-conformant ways of catsing your callback type |
977 | More interesting and less C\-conformant ways of casting your callback type |
822 | have been omitted.... |
978 | instead have been omitted. |
|
|
979 | .PP |
|
|
980 | Another common scenario is having some data structure with multiple |
|
|
981 | watchers: |
|
|
982 | .PP |
|
|
983 | .Vb 6 |
|
|
984 | \& struct my_biggy |
|
|
985 | \& { |
|
|
986 | \& int some_data; |
|
|
987 | \& ev_timer t1; |
|
|
988 | \& ev_timer t2; |
|
|
989 | \& } |
|
|
990 | .Ve |
|
|
991 | .PP |
|
|
992 | In this case getting the pointer to \f(CW\*(C`my_biggy\*(C'\fR is a bit more complicated, |
|
|
993 | you need to use \f(CW\*(C`offsetof\*(C'\fR: |
|
|
994 | .PP |
|
|
995 | .Vb 1 |
|
|
996 | \& #include <stddef.h> |
|
|
997 | .Ve |
|
|
998 | .PP |
|
|
999 | .Vb 6 |
|
|
1000 | \& static void |
|
|
1001 | \& t1_cb (EV_P_ struct ev_timer *w, int revents) |
|
|
1002 | \& { |
|
|
1003 | \& struct my_biggy big = (struct my_biggy * |
|
|
1004 | \& (((char *)w) - offsetof (struct my_biggy, t1)); |
|
|
1005 | \& } |
|
|
1006 | .Ve |
|
|
1007 | .PP |
|
|
1008 | .Vb 6 |
|
|
1009 | \& static void |
|
|
1010 | \& t2_cb (EV_P_ struct ev_timer *w, int revents) |
|
|
1011 | \& { |
|
|
1012 | \& struct my_biggy big = (struct my_biggy * |
|
|
1013 | \& (((char *)w) - offsetof (struct my_biggy, t2)); |
|
|
1014 | \& } |
|
|
1015 | .Ve |
823 | .SH "WATCHER TYPES" |
1016 | .SH "WATCHER TYPES" |
824 | .IX Header "WATCHER TYPES" |
1017 | .IX Header "WATCHER TYPES" |
825 | This section describes each watcher in detail, but will not repeat |
1018 | This section describes each watcher in detail, but will not repeat |
826 | information given in the last section. |
1019 | information given in the last section. Any initialisation/set macros, |
|
|
1020 | functions and members specific to the watcher type are explained. |
|
|
1021 | .PP |
|
|
1022 | Members are additionally marked with either \fI[read\-only]\fR, meaning that, |
|
|
1023 | while the watcher is active, you can look at the member and expect some |
|
|
1024 | sensible content, but you must not modify it (you can modify it while the |
|
|
1025 | watcher is stopped to your hearts content), or \fI[read\-write]\fR, which |
|
|
1026 | means you can expect it to have some sensible content while the watcher |
|
|
1027 | is active, but you can also modify it. Modifying it may not do something |
|
|
1028 | sensible or take immediate effect (or do anything at all), but libev will |
|
|
1029 | not crash or malfunction in any way. |
827 | .ie n .Sh """ev_io"" \- is this file descriptor readable or writable?" |
1030 | .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?" |
1031 | .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?" |
1032 | .IX Subsection "ev_io - is this file descriptor readable or writable?" |
830 | I/O watchers check whether a file descriptor is readable or writable |
1033 | I/O watchers check whether a file descriptor is readable or writable |
831 | in each iteration of the event loop, or, more precisely, when reading |
1034 | in each iteration of the event loop, or, more precisely, when reading |
… | |
… | |
859 | it is best to always use non-blocking I/O: An extra \f(CW\*(C`read\*(C'\fR(2) returning |
1062 | it is best to always use non-blocking I/O: An extra \f(CW\*(C`read\*(C'\fR(2) returning |
860 | \&\f(CW\*(C`EAGAIN\*(C'\fR is far preferable to a program hanging until some data arrives. |
1063 | \&\f(CW\*(C`EAGAIN\*(C'\fR is far preferable to a program hanging until some data arrives. |
861 | .PP |
1064 | .PP |
862 | If you cannot run the fd in non-blocking mode (for example you should not |
1065 | If you cannot run the fd in non-blocking mode (for example you should not |
863 | play around with an Xlib connection), then you have to seperately re-test |
1066 | play around with an Xlib connection), then you have to seperately re-test |
864 | wether a file descriptor is really ready with a known-to-be good interface |
1067 | whether a file descriptor is really ready with a known-to-be good interface |
865 | such as poll (fortunately in our Xlib example, Xlib already does this on |
1068 | such as poll (fortunately in our Xlib example, Xlib already does this on |
866 | its own, so its quite safe to use). |
1069 | its own, so its quite safe to use). |
|
|
1070 | .PP |
|
|
1071 | \fIThe special problem of disappearing file descriptors\fR |
|
|
1072 | .IX Subsection "The special problem of disappearing file descriptors" |
|
|
1073 | .PP |
|
|
1074 | Some backends (e.g kqueue, epoll) need to be told about closing a file |
|
|
1075 | descriptor (either by calling \f(CW\*(C`close\*(C'\fR explicitly or by any other means, |
|
|
1076 | such as \f(CW\*(C`dup\*(C'\fR). The reason is that you register interest in some file |
|
|
1077 | descriptor, but when it goes away, the operating system will silently drop |
|
|
1078 | this interest. If another file descriptor with the same number then is |
|
|
1079 | registered with libev, there is no efficient way to see that this is, in |
|
|
1080 | fact, a different file descriptor. |
|
|
1081 | .PP |
|
|
1082 | To avoid having to explicitly tell libev about such cases, libev follows |
|
|
1083 | the following policy: Each time \f(CW\*(C`ev_io_set\*(C'\fR is being called, libev |
|
|
1084 | will assume that this is potentially a new file descriptor, otherwise |
|
|
1085 | it is assumed that the file descriptor stays the same. That means that |
|
|
1086 | you \fIhave\fR to call \f(CW\*(C`ev_io_set\*(C'\fR (or \f(CW\*(C`ev_io_init\*(C'\fR) when you change the |
|
|
1087 | descriptor even if the file descriptor number itself did not change. |
|
|
1088 | .PP |
|
|
1089 | This is how one would do it normally anyway, the important point is that |
|
|
1090 | the libev application should not optimise around libev but should leave |
|
|
1091 | optimisations to libev. |
|
|
1092 | .PP |
|
|
1093 | \fIWatcher-Specific Functions\fR |
|
|
1094 | .IX Subsection "Watcher-Specific Functions" |
867 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
1095 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
868 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
1096 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
869 | .PD 0 |
1097 | .PD 0 |
870 | .IP "ev_io_set (ev_io *, int fd, int events)" 4 |
1098 | .IP "ev_io_set (ev_io *, int fd, int events)" 4 |
871 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
1099 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
872 | .PD |
1100 | .PD |
873 | Configures an \f(CW\*(C`ev_io\*(C'\fR watcher. The \f(CW\*(C`fd\*(C'\fR is the file descriptor to |
1101 | Configures an \f(CW\*(C`ev_io\*(C'\fR watcher. The \f(CW\*(C`fd\*(C'\fR is the file descriptor to |
874 | rceeive events for and events is either \f(CW\*(C`EV_READ\*(C'\fR, \f(CW\*(C`EV_WRITE\*(C'\fR or |
1102 | rceeive events for and events is either \f(CW\*(C`EV_READ\*(C'\fR, \f(CW\*(C`EV_WRITE\*(C'\fR or |
875 | \&\f(CW\*(C`EV_READ | EV_WRITE\*(C'\fR to receive the given events. |
1103 | \&\f(CW\*(C`EV_READ | EV_WRITE\*(C'\fR to receive the given events. |
|
|
1104 | .IP "int fd [read\-only]" 4 |
|
|
1105 | .IX Item "int fd [read-only]" |
|
|
1106 | The file descriptor being watched. |
|
|
1107 | .IP "int events [read\-only]" 4 |
|
|
1108 | .IX Item "int events [read-only]" |
|
|
1109 | The events being watched. |
876 | .PP |
1110 | .PP |
877 | Example: call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well |
1111 | Example: Call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well |
878 | readable, but only once. Since it is likely line\-buffered, you could |
1112 | readable, but only once. Since it is likely line\-buffered, you could |
879 | attempt to read a whole line in the callback: |
1113 | attempt to read a whole line in the callback. |
880 | .PP |
1114 | .PP |
881 | .Vb 6 |
1115 | .Vb 6 |
882 | \& static void |
1116 | \& static void |
883 | \& stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
1117 | \& stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
884 | \& { |
1118 | \& { |
… | |
… | |
918 | .Ve |
1152 | .Ve |
919 | .PP |
1153 | .PP |
920 | The callback is guarenteed to be invoked only when its timeout has passed, |
1154 | The callback is guarenteed to be invoked only when its timeout has passed, |
921 | but if multiple timers become ready during the same loop iteration then |
1155 | but if multiple timers become ready during the same loop iteration then |
922 | order of execution is undefined. |
1156 | order of execution is undefined. |
|
|
1157 | .PP |
|
|
1158 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1159 | .IX Subsection "Watcher-Specific Functions and Data Members" |
923 | .IP "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" 4 |
1160 | .IP "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" 4 |
924 | .IX Item "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" |
1161 | .IX Item "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" |
925 | .PD 0 |
1162 | .PD 0 |
926 | .IP "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)" 4 |
1163 | .IP "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)" 4 |
927 | .IX Item "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)" |
1164 | .IX Item "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)" |
… | |
… | |
939 | .IP "ev_timer_again (loop)" 4 |
1176 | .IP "ev_timer_again (loop)" 4 |
940 | .IX Item "ev_timer_again (loop)" |
1177 | .IX Item "ev_timer_again (loop)" |
941 | This will act as if the timer timed out and restart it again if it is |
1178 | This will act as if the timer timed out and restart it again if it is |
942 | repeating. The exact semantics are: |
1179 | repeating. The exact semantics are: |
943 | .Sp |
1180 | .Sp |
|
|
1181 | If the timer is pending, its pending status is cleared. |
|
|
1182 | .Sp |
944 | If the timer is started but nonrepeating, stop it. |
1183 | If the timer is started but nonrepeating, stop it (as if it timed out). |
945 | .Sp |
1184 | .Sp |
946 | If the timer is repeating, either start it if necessary (with the repeat |
1185 | If the timer is repeating, either start it if necessary (with the |
947 | value), or reset the running timer to the repeat value. |
1186 | \&\f(CW\*(C`repeat\*(C'\fR value), or reset the running timer to the \f(CW\*(C`repeat\*(C'\fR value. |
948 | .Sp |
1187 | .Sp |
949 | This sounds a bit complicated, but here is a useful and typical |
1188 | This sounds a bit complicated, but here is a useful and typical |
950 | example: Imagine you have a tcp connection and you want a so-called idle |
1189 | example: Imagine you have a tcp connection and you want a so-called idle |
951 | timeout, that is, you want to be called when there have been, say, 60 |
1190 | timeout, that is, you want to be called when there have been, say, 60 |
952 | seconds of inactivity on the socket. The easiest way to do this is to |
1191 | seconds of inactivity on the socket. The easiest way to do this is to |
953 | configure an \f(CW\*(C`ev_timer\*(C'\fR with after=repeat=60 and calling ev_timer_again each |
1192 | 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 |
954 | time you successfully read or write some data. If you go into an idle |
1193 | \&\f(CW\*(C`ev_timer_again\*(C'\fR each time you successfully read or write some data. If |
955 | state where you do not expect data to travel on the socket, you can stop |
1194 | you go into an idle state where you do not expect data to travel on the |
956 | the timer, and again will automatically restart it if need be. |
1195 | socket, you can \f(CW\*(C`ev_timer_stop\*(C'\fR the timer, and \f(CW\*(C`ev_timer_again\*(C'\fR will |
|
|
1196 | automatically restart it if need be. |
|
|
1197 | .Sp |
|
|
1198 | That means you can ignore the \f(CW\*(C`after\*(C'\fR value and \f(CW\*(C`ev_timer_start\*(C'\fR |
|
|
1199 | altogether and only ever use the \f(CW\*(C`repeat\*(C'\fR value and \f(CW\*(C`ev_timer_again\*(C'\fR: |
|
|
1200 | .Sp |
|
|
1201 | .Vb 8 |
|
|
1202 | \& ev_timer_init (timer, callback, 0., 5.); |
|
|
1203 | \& ev_timer_again (loop, timer); |
|
|
1204 | \& ... |
|
|
1205 | \& timer->again = 17.; |
|
|
1206 | \& ev_timer_again (loop, timer); |
|
|
1207 | \& ... |
|
|
1208 | \& timer->again = 10.; |
|
|
1209 | \& ev_timer_again (loop, timer); |
|
|
1210 | .Ve |
|
|
1211 | .Sp |
|
|
1212 | This is more slightly efficient then stopping/starting the timer each time |
|
|
1213 | you want to modify its timeout value. |
|
|
1214 | .IP "ev_tstamp repeat [read\-write]" 4 |
|
|
1215 | .IX Item "ev_tstamp repeat [read-write]" |
|
|
1216 | The current \f(CW\*(C`repeat\*(C'\fR value. Will be used each time the watcher times out |
|
|
1217 | or \f(CW\*(C`ev_timer_again\*(C'\fR is called and determines the next timeout (if any), |
|
|
1218 | which is also when any modifications are taken into account. |
957 | .PP |
1219 | .PP |
958 | Example: create a timer that fires after 60 seconds. |
1220 | Example: Create a timer that fires after 60 seconds. |
959 | .PP |
1221 | .PP |
960 | .Vb 5 |
1222 | .Vb 5 |
961 | \& static void |
1223 | \& static void |
962 | \& one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1224 | \& one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
963 | \& { |
1225 | \& { |
… | |
… | |
969 | \& struct ev_timer mytimer; |
1231 | \& struct ev_timer mytimer; |
970 | \& ev_timer_init (&mytimer, one_minute_cb, 60., 0.); |
1232 | \& ev_timer_init (&mytimer, one_minute_cb, 60., 0.); |
971 | \& ev_timer_start (loop, &mytimer); |
1233 | \& ev_timer_start (loop, &mytimer); |
972 | .Ve |
1234 | .Ve |
973 | .PP |
1235 | .PP |
974 | Example: create a timeout timer that times out after 10 seconds of |
1236 | Example: Create a timeout timer that times out after 10 seconds of |
975 | inactivity. |
1237 | inactivity. |
976 | .PP |
1238 | .PP |
977 | .Vb 5 |
1239 | .Vb 5 |
978 | \& static void |
1240 | \& static void |
979 | \& timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1241 | \& timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
… | |
… | |
1004 | but on wallclock time (absolute time). You can tell a periodic watcher |
1266 | but on wallclock time (absolute time). You can tell a periodic watcher |
1005 | to trigger \*(L"at\*(R" some specific point in time. For example, if you tell a |
1267 | to trigger \*(L"at\*(R" some specific point in time. For example, if you tell a |
1006 | periodic watcher to trigger in 10 seconds (by specifiying e.g. \f(CW\*(C`ev_now () |
1268 | periodic watcher to trigger in 10 seconds (by specifiying e.g. \f(CW\*(C`ev_now () |
1007 | + 10.\*(C'\fR) and then reset your system clock to the last year, then it will |
1269 | + 10.\*(C'\fR) and then reset your system clock to the last year, then it will |
1008 | take a year to trigger the event (unlike an \f(CW\*(C`ev_timer\*(C'\fR, which would trigger |
1270 | take a year to trigger the event (unlike an \f(CW\*(C`ev_timer\*(C'\fR, which would trigger |
1009 | roughly 10 seconds later and of course not if you reset your system time |
1271 | roughly 10 seconds later). |
1010 | again). |
|
|
1011 | .PP |
1272 | .PP |
1012 | They can also be used to implement vastly more complex timers, such as |
1273 | They can also be used to implement vastly more complex timers, such as |
1013 | triggering an event on eahc midnight, local time. |
1274 | triggering an event on each midnight, local time or other, complicated, |
|
|
1275 | rules. |
1014 | .PP |
1276 | .PP |
1015 | As with timers, the callback is guarenteed to be invoked only when the |
1277 | As with timers, the callback is guarenteed to be invoked only when the |
1016 | time (\f(CW\*(C`at\*(C'\fR) has been passed, but if multiple periodic timers become ready |
1278 | time (\f(CW\*(C`at\*(C'\fR) has been passed, but if multiple periodic timers become ready |
1017 | during the same loop iteration then order of execution is undefined. |
1279 | during the same loop iteration then order of execution is undefined. |
|
|
1280 | .PP |
|
|
1281 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1282 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1018 | .IP "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" 4 |
1283 | .IP "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" 4 |
1019 | .IX Item "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" |
1284 | .IX Item "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" |
1020 | .PD 0 |
1285 | .PD 0 |
1021 | .IP "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" 4 |
1286 | .IP "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" 4 |
1022 | .IX Item "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" |
1287 | .IX Item "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" |
1023 | .PD |
1288 | .PD |
1024 | Lots of arguments, lets sort it out... There are basically three modes of |
1289 | Lots of arguments, lets sort it out... There are basically three modes of |
1025 | operation, and we will explain them from simplest to complex: |
1290 | operation, and we will explain them from simplest to complex: |
1026 | .RS 4 |
1291 | .RS 4 |
1027 | .IP "* absolute timer (interval = reschedule_cb = 0)" 4 |
1292 | .IP "* absolute timer (at = time, interval = reschedule_cb = 0)" 4 |
1028 | .IX Item "absolute timer (interval = reschedule_cb = 0)" |
1293 | .IX Item "absolute timer (at = time, interval = reschedule_cb = 0)" |
1029 | In this configuration the watcher triggers an event at the wallclock time |
1294 | In this configuration the watcher triggers an event at the wallclock time |
1030 | \&\f(CW\*(C`at\*(C'\fR and doesn't repeat. It will not adjust when a time jump occurs, |
1295 | \&\f(CW\*(C`at\*(C'\fR and doesn't repeat. It will not adjust when a time jump occurs, |
1031 | that is, if it is to be run at January 1st 2011 then it will run when the |
1296 | that is, if it is to be run at January 1st 2011 then it will run when the |
1032 | system time reaches or surpasses this time. |
1297 | system time reaches or surpasses this time. |
1033 | .IP "* non-repeating interval timer (interval > 0, reschedule_cb = 0)" 4 |
1298 | .IP "* non-repeating interval timer (at = offset, interval > 0, reschedule_cb = 0)" 4 |
1034 | .IX Item "non-repeating interval timer (interval > 0, reschedule_cb = 0)" |
1299 | .IX Item "non-repeating interval timer (at = offset, interval > 0, reschedule_cb = 0)" |
1035 | In this mode the watcher will always be scheduled to time out at the next |
1300 | In this mode the watcher will always be scheduled to time out at the next |
1036 | \&\f(CW\*(C`at + N * interval\*(C'\fR time (for some integer N) and then repeat, regardless |
1301 | \&\f(CW\*(C`at + N * interval\*(C'\fR time (for some integer N, which can also be negative) |
1037 | of any time jumps. |
1302 | and then repeat, regardless of any time jumps. |
1038 | .Sp |
1303 | .Sp |
1039 | This can be used to create timers that do not drift with respect to system |
1304 | This can be used to create timers that do not drift with respect to system |
1040 | time: |
1305 | time: |
1041 | .Sp |
1306 | .Sp |
1042 | .Vb 1 |
1307 | .Vb 1 |
… | |
… | |
1049 | by 3600. |
1314 | by 3600. |
1050 | .Sp |
1315 | .Sp |
1051 | Another way to think about it (for the mathematically inclined) is that |
1316 | Another way to think about it (for the mathematically inclined) is that |
1052 | \&\f(CW\*(C`ev_periodic\*(C'\fR will try to run the callback in this mode at the next possible |
1317 | \&\f(CW\*(C`ev_periodic\*(C'\fR will try to run the callback in this mode at the next possible |
1053 | time where \f(CW\*(C`time = at (mod interval)\*(C'\fR, regardless of any time jumps. |
1318 | time where \f(CW\*(C`time = at (mod interval)\*(C'\fR, regardless of any time jumps. |
|
|
1319 | .Sp |
|
|
1320 | For numerical stability it is preferable that the \f(CW\*(C`at\*(C'\fR value is near |
|
|
1321 | \&\f(CW\*(C`ev_now ()\*(C'\fR (the current time), but there is no range requirement for |
|
|
1322 | this value. |
1054 | .IP "* manual reschedule mode (reschedule_cb = callback)" 4 |
1323 | .IP "* manual reschedule mode (at and interval ignored, reschedule_cb = callback)" 4 |
1055 | .IX Item "manual reschedule mode (reschedule_cb = callback)" |
1324 | .IX Item "manual reschedule mode (at and interval ignored, reschedule_cb = callback)" |
1056 | In this mode the values for \f(CW\*(C`interval\*(C'\fR and \f(CW\*(C`at\*(C'\fR are both being |
1325 | In this mode the values for \f(CW\*(C`interval\*(C'\fR and \f(CW\*(C`at\*(C'\fR are both being |
1057 | ignored. Instead, each time the periodic watcher gets scheduled, the |
1326 | ignored. Instead, each time the periodic watcher gets scheduled, the |
1058 | reschedule callback will be called with the watcher as first, and the |
1327 | reschedule callback will be called with the watcher as first, and the |
1059 | current time as second argument. |
1328 | current time as second argument. |
1060 | .Sp |
1329 | .Sp |
1061 | \&\s-1NOTE:\s0 \fIThis callback \s-1MUST\s0 \s-1NOT\s0 stop or destroy any periodic watcher, |
1330 | \&\s-1NOTE:\s0 \fIThis callback \s-1MUST\s0 \s-1NOT\s0 stop or destroy any periodic watcher, |
1062 | ever, or make any event loop modifications\fR. If you need to stop it, |
1331 | ever, or make any event loop modifications\fR. If you need to stop it, |
1063 | return \f(CW\*(C`now + 1e30\*(C'\fR (or so, fudge fudge) and stop it afterwards (e.g. by |
1332 | return \f(CW\*(C`now + 1e30\*(C'\fR (or so, fudge fudge) and stop it afterwards (e.g. by |
1064 | starting a prepare watcher). |
1333 | starting an \f(CW\*(C`ev_prepare\*(C'\fR watcher, which is legal). |
1065 | .Sp |
1334 | .Sp |
1066 | Its prototype is \f(CW\*(C`ev_tstamp (*reschedule_cb)(struct ev_periodic *w, |
1335 | Its prototype is \f(CW\*(C`ev_tstamp (*reschedule_cb)(struct ev_periodic *w, |
1067 | ev_tstamp now)\*(C'\fR, e.g.: |
1336 | ev_tstamp now)\*(C'\fR, e.g.: |
1068 | .Sp |
1337 | .Sp |
1069 | .Vb 4 |
1338 | .Vb 4 |
… | |
… | |
1093 | .IX Item "ev_periodic_again (loop, ev_periodic *)" |
1362 | .IX Item "ev_periodic_again (loop, ev_periodic *)" |
1094 | Simply stops and restarts the periodic watcher again. This is only useful |
1363 | Simply stops and restarts the periodic watcher again. This is only useful |
1095 | when you changed some parameters or the reschedule callback would return |
1364 | when you changed some parameters or the reschedule callback would return |
1096 | a different time than the last time it was called (e.g. in a crond like |
1365 | a different time than the last time it was called (e.g. in a crond like |
1097 | program when the crontabs have changed). |
1366 | program when the crontabs have changed). |
|
|
1367 | .IP "ev_tstamp offset [read\-write]" 4 |
|
|
1368 | .IX Item "ev_tstamp offset [read-write]" |
|
|
1369 | When repeating, this contains the offset value, otherwise this is the |
|
|
1370 | absolute point in time (the \f(CW\*(C`at\*(C'\fR value passed to \f(CW\*(C`ev_periodic_set\*(C'\fR). |
|
|
1371 | .Sp |
|
|
1372 | Can be modified any time, but changes only take effect when the periodic |
|
|
1373 | timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called. |
|
|
1374 | .IP "ev_tstamp interval [read\-write]" 4 |
|
|
1375 | .IX Item "ev_tstamp interval [read-write]" |
|
|
1376 | The current interval value. Can be modified any time, but changes only |
|
|
1377 | take effect when the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being |
|
|
1378 | called. |
|
|
1379 | .IP "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read\-write]" 4 |
|
|
1380 | .IX Item "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write]" |
|
|
1381 | The current reschedule callback, or \f(CW0\fR, if this functionality is |
|
|
1382 | switched off. Can be changed any time, but changes only take effect when |
|
|
1383 | the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called. |
1098 | .PP |
1384 | .PP |
1099 | Example: call a callback every hour, or, more precisely, whenever the |
1385 | Example: Call a callback every hour, or, more precisely, whenever the |
1100 | system clock is divisible by 3600. The callback invocation times have |
1386 | system clock is divisible by 3600. The callback invocation times have |
1101 | potentially a lot of jittering, but good long-term stability. |
1387 | potentially a lot of jittering, but good long-term stability. |
1102 | .PP |
1388 | .PP |
1103 | .Vb 5 |
1389 | .Vb 5 |
1104 | \& static void |
1390 | \& static void |
… | |
… | |
1112 | \& struct ev_periodic hourly_tick; |
1398 | \& struct ev_periodic hourly_tick; |
1113 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); |
1399 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); |
1114 | \& ev_periodic_start (loop, &hourly_tick); |
1400 | \& ev_periodic_start (loop, &hourly_tick); |
1115 | .Ve |
1401 | .Ve |
1116 | .PP |
1402 | .PP |
1117 | Example: the same as above, but use a reschedule callback to do it: |
1403 | Example: The same as above, but use a reschedule callback to do it: |
1118 | .PP |
1404 | .PP |
1119 | .Vb 1 |
1405 | .Vb 1 |
1120 | \& #include <math.h> |
1406 | \& #include <math.h> |
1121 | .Ve |
1407 | .Ve |
1122 | .PP |
1408 | .PP |
… | |
… | |
1130 | .PP |
1416 | .PP |
1131 | .Vb 1 |
1417 | .Vb 1 |
1132 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); |
1418 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); |
1133 | .Ve |
1419 | .Ve |
1134 | .PP |
1420 | .PP |
1135 | Example: call a callback every hour, starting now: |
1421 | Example: Call a callback every hour, starting now: |
1136 | .PP |
1422 | .PP |
1137 | .Vb 4 |
1423 | .Vb 4 |
1138 | \& struct ev_periodic hourly_tick; |
1424 | \& struct ev_periodic hourly_tick; |
1139 | \& ev_periodic_init (&hourly_tick, clock_cb, |
1425 | \& ev_periodic_init (&hourly_tick, clock_cb, |
1140 | \& fmod (ev_now (loop), 3600.), 3600., 0); |
1426 | \& fmod (ev_now (loop), 3600.), 3600., 0); |
… | |
… | |
1152 | first watcher gets started will libev actually register a signal watcher |
1438 | first watcher gets started will libev actually register a signal watcher |
1153 | with the kernel (thus it coexists with your own signal handlers as long |
1439 | with the kernel (thus it coexists with your own signal handlers as long |
1154 | as you don't register any with libev). Similarly, when the last signal |
1440 | as you don't register any with libev). Similarly, when the last signal |
1155 | watcher for a signal is stopped libev will reset the signal handler to |
1441 | watcher for a signal is stopped libev will reset the signal handler to |
1156 | \&\s-1SIG_DFL\s0 (regardless of what it was set to before). |
1442 | \&\s-1SIG_DFL\s0 (regardless of what it was set to before). |
|
|
1443 | .PP |
|
|
1444 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1445 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1157 | .IP "ev_signal_init (ev_signal *, callback, int signum)" 4 |
1446 | .IP "ev_signal_init (ev_signal *, callback, int signum)" 4 |
1158 | .IX Item "ev_signal_init (ev_signal *, callback, int signum)" |
1447 | .IX Item "ev_signal_init (ev_signal *, callback, int signum)" |
1159 | .PD 0 |
1448 | .PD 0 |
1160 | .IP "ev_signal_set (ev_signal *, int signum)" 4 |
1449 | .IP "ev_signal_set (ev_signal *, int signum)" 4 |
1161 | .IX Item "ev_signal_set (ev_signal *, int signum)" |
1450 | .IX Item "ev_signal_set (ev_signal *, int signum)" |
1162 | .PD |
1451 | .PD |
1163 | Configures the watcher to trigger on the given signal number (usually one |
1452 | Configures the watcher to trigger on the given signal number (usually one |
1164 | of the \f(CW\*(C`SIGxxx\*(C'\fR constants). |
1453 | of the \f(CW\*(C`SIGxxx\*(C'\fR constants). |
|
|
1454 | .IP "int signum [read\-only]" 4 |
|
|
1455 | .IX Item "int signum [read-only]" |
|
|
1456 | The signal the watcher watches out for. |
1165 | .ie n .Sh """ev_child"" \- watch out for process status changes" |
1457 | .ie n .Sh """ev_child"" \- watch out for process status changes" |
1166 | .el .Sh "\f(CWev_child\fP \- watch out for process status changes" |
1458 | .el .Sh "\f(CWev_child\fP \- watch out for process status changes" |
1167 | .IX Subsection "ev_child - watch out for process status changes" |
1459 | .IX Subsection "ev_child - watch out for process status changes" |
1168 | Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to |
1460 | Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to |
1169 | some child status changes (most typically when a child of yours dies). |
1461 | some child status changes (most typically when a child of yours dies). |
|
|
1462 | .PP |
|
|
1463 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1464 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1170 | .IP "ev_child_init (ev_child *, callback, int pid)" 4 |
1465 | .IP "ev_child_init (ev_child *, callback, int pid)" 4 |
1171 | .IX Item "ev_child_init (ev_child *, callback, int pid)" |
1466 | .IX Item "ev_child_init (ev_child *, callback, int pid)" |
1172 | .PD 0 |
1467 | .PD 0 |
1173 | .IP "ev_child_set (ev_child *, int pid)" 4 |
1468 | .IP "ev_child_set (ev_child *, int pid)" 4 |
1174 | .IX Item "ev_child_set (ev_child *, int pid)" |
1469 | .IX Item "ev_child_set (ev_child *, int pid)" |
… | |
… | |
1177 | \&\fIany\fR process if \f(CW\*(C`pid\*(C'\fR is specified as \f(CW0\fR). The callback can look |
1472 | \&\fIany\fR process if \f(CW\*(C`pid\*(C'\fR is specified as \f(CW0\fR). The callback can look |
1178 | at the \f(CW\*(C`rstatus\*(C'\fR member of the \f(CW\*(C`ev_child\*(C'\fR watcher structure to see |
1473 | at the \f(CW\*(C`rstatus\*(C'\fR member of the \f(CW\*(C`ev_child\*(C'\fR watcher structure to see |
1179 | the status word (use the macros from \f(CW\*(C`sys/wait.h\*(C'\fR and see your systems |
1474 | the status word (use the macros from \f(CW\*(C`sys/wait.h\*(C'\fR and see your systems |
1180 | \&\f(CW\*(C`waitpid\*(C'\fR documentation). The \f(CW\*(C`rpid\*(C'\fR member contains the pid of the |
1475 | \&\f(CW\*(C`waitpid\*(C'\fR documentation). The \f(CW\*(C`rpid\*(C'\fR member contains the pid of the |
1181 | process causing the status change. |
1476 | process causing the status change. |
|
|
1477 | .IP "int pid [read\-only]" 4 |
|
|
1478 | .IX Item "int pid [read-only]" |
|
|
1479 | The process id this watcher watches out for, or \f(CW0\fR, meaning any process id. |
|
|
1480 | .IP "int rpid [read\-write]" 4 |
|
|
1481 | .IX Item "int rpid [read-write]" |
|
|
1482 | The process id that detected a status change. |
|
|
1483 | .IP "int rstatus [read\-write]" 4 |
|
|
1484 | .IX Item "int rstatus [read-write]" |
|
|
1485 | The process exit/trace status caused by \f(CW\*(C`rpid\*(C'\fR (see your systems |
|
|
1486 | \&\f(CW\*(C`waitpid\*(C'\fR and \f(CW\*(C`sys/wait.h\*(C'\fR documentation for details). |
1182 | .PP |
1487 | .PP |
1183 | Example: try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0. |
1488 | Example: Try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0. |
1184 | .PP |
1489 | .PP |
1185 | .Vb 5 |
1490 | .Vb 5 |
1186 | \& static void |
1491 | \& static void |
1187 | \& sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
1492 | \& sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
1188 | \& { |
1493 | \& { |
… | |
… | |
1193 | .Vb 3 |
1498 | .Vb 3 |
1194 | \& struct ev_signal signal_watcher; |
1499 | \& struct ev_signal signal_watcher; |
1195 | \& ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
1500 | \& ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
1196 | \& ev_signal_start (loop, &sigint_cb); |
1501 | \& ev_signal_start (loop, &sigint_cb); |
1197 | .Ve |
1502 | .Ve |
|
|
1503 | .ie n .Sh """ev_stat"" \- did the file attributes just change?" |
|
|
1504 | .el .Sh "\f(CWev_stat\fP \- did the file attributes just change?" |
|
|
1505 | .IX Subsection "ev_stat - did the file attributes just change?" |
|
|
1506 | This watches a filesystem path for attribute changes. That is, it calls |
|
|
1507 | \&\f(CW\*(C`stat\*(C'\fR regularly (or when the \s-1OS\s0 says it changed) and sees if it changed |
|
|
1508 | compared to the last time, invoking the callback if it did. |
|
|
1509 | .PP |
|
|
1510 | The path does not need to exist: changing from \*(L"path exists\*(R" to \*(L"path does |
|
|
1511 | not exist\*(R" is a status change like any other. The condition \*(L"path does |
|
|
1512 | not exist\*(R" is signified by the \f(CW\*(C`st_nlink\*(C'\fR field being zero (which is |
|
|
1513 | otherwise always forced to be at least one) and all the other fields of |
|
|
1514 | the stat buffer having unspecified contents. |
|
|
1515 | .PP |
|
|
1516 | The path \fIshould\fR be absolute and \fImust not\fR end in a slash. If it is |
|
|
1517 | relative and your working directory changes, the behaviour is undefined. |
|
|
1518 | .PP |
|
|
1519 | Since there is no standard to do this, the portable implementation simply |
|
|
1520 | calls \f(CW\*(C`stat (2)\*(C'\fR regularly on the path to see if it changed somehow. You |
|
|
1521 | can specify a recommended polling interval for this case. If you specify |
|
|
1522 | a polling interval of \f(CW0\fR (highly recommended!) then a \fIsuitable, |
|
|
1523 | unspecified default\fR value will be used (which you can expect to be around |
|
|
1524 | five seconds, although this might change dynamically). Libev will also |
|
|
1525 | impose a minimum interval which is currently around \f(CW0.1\fR, but thats |
|
|
1526 | usually overkill. |
|
|
1527 | .PP |
|
|
1528 | This watcher type is not meant for massive numbers of stat watchers, |
|
|
1529 | as even with OS-supported change notifications, this can be |
|
|
1530 | resource\-intensive. |
|
|
1531 | .PP |
|
|
1532 | At the time of this writing, only the Linux inotify interface is |
|
|
1533 | implemented (implementing kqueue support is left as an exercise for the |
|
|
1534 | reader). Inotify will be used to give hints only and should not change the |
|
|
1535 | semantics of \f(CW\*(C`ev_stat\*(C'\fR watchers, which means that libev sometimes needs |
|
|
1536 | to fall back to regular polling again even with inotify, but changes are |
|
|
1537 | usually detected immediately, and if the file exists there will be no |
|
|
1538 | polling. |
|
|
1539 | .PP |
|
|
1540 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1541 | .IX Subsection "Watcher-Specific Functions and Data Members" |
|
|
1542 | .IP "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" 4 |
|
|
1543 | .IX Item "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" |
|
|
1544 | .PD 0 |
|
|
1545 | .IP "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" 4 |
|
|
1546 | .IX Item "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" |
|
|
1547 | .PD |
|
|
1548 | Configures the watcher to wait for status changes of the given |
|
|
1549 | \&\f(CW\*(C`path\*(C'\fR. The \f(CW\*(C`interval\*(C'\fR is a hint on how quickly a change is expected to |
|
|
1550 | be detected and should normally be specified as \f(CW0\fR to let libev choose |
|
|
1551 | a suitable value. The memory pointed to by \f(CW\*(C`path\*(C'\fR must point to the same |
|
|
1552 | path for as long as the watcher is active. |
|
|
1553 | .Sp |
|
|
1554 | The callback will be receive \f(CW\*(C`EV_STAT\*(C'\fR when a change was detected, |
|
|
1555 | relative to the attributes at the time the watcher was started (or the |
|
|
1556 | last change was detected). |
|
|
1557 | .IP "ev_stat_stat (ev_stat *)" 4 |
|
|
1558 | .IX Item "ev_stat_stat (ev_stat *)" |
|
|
1559 | Updates the stat buffer immediately with new values. If you change the |
|
|
1560 | watched path in your callback, you could call this fucntion to avoid |
|
|
1561 | detecting this change (while introducing a race condition). Can also be |
|
|
1562 | useful simply to find out the new values. |
|
|
1563 | .IP "ev_statdata attr [read\-only]" 4 |
|
|
1564 | .IX Item "ev_statdata attr [read-only]" |
|
|
1565 | The most-recently detected attributes of the file. Although the type is of |
|
|
1566 | \&\f(CW\*(C`ev_statdata\*(C'\fR, this is usually the (or one of the) \f(CW\*(C`struct stat\*(C'\fR types |
|
|
1567 | suitable for your system. If the \f(CW\*(C`st_nlink\*(C'\fR member is \f(CW0\fR, then there |
|
|
1568 | was some error while \f(CW\*(C`stat\*(C'\fRing the file. |
|
|
1569 | .IP "ev_statdata prev [read\-only]" 4 |
|
|
1570 | .IX Item "ev_statdata prev [read-only]" |
|
|
1571 | The previous attributes of the file. The callback gets invoked whenever |
|
|
1572 | \&\f(CW\*(C`prev\*(C'\fR != \f(CW\*(C`attr\*(C'\fR. |
|
|
1573 | .IP "ev_tstamp interval [read\-only]" 4 |
|
|
1574 | .IX Item "ev_tstamp interval [read-only]" |
|
|
1575 | The specified interval. |
|
|
1576 | .IP "const char *path [read\-only]" 4 |
|
|
1577 | .IX Item "const char *path [read-only]" |
|
|
1578 | The filesystem path that is being watched. |
|
|
1579 | .PP |
|
|
1580 | Example: Watch \f(CW\*(C`/etc/passwd\*(C'\fR for attribute changes. |
|
|
1581 | .PP |
|
|
1582 | .Vb 15 |
|
|
1583 | \& static void |
|
|
1584 | \& passwd_cb (struct ev_loop *loop, ev_stat *w, int revents) |
|
|
1585 | \& { |
|
|
1586 | \& /* /etc/passwd changed in some way */ |
|
|
1587 | \& if (w->attr.st_nlink) |
|
|
1588 | \& { |
|
|
1589 | \& printf ("passwd current size %ld\en", (long)w->attr.st_size); |
|
|
1590 | \& printf ("passwd current atime %ld\en", (long)w->attr.st_mtime); |
|
|
1591 | \& printf ("passwd current mtime %ld\en", (long)w->attr.st_mtime); |
|
|
1592 | \& } |
|
|
1593 | \& else |
|
|
1594 | \& /* you shalt not abuse printf for puts */ |
|
|
1595 | \& puts ("wow, /etc/passwd is not there, expect problems. " |
|
|
1596 | \& "if this is windows, they already arrived\en"); |
|
|
1597 | \& } |
|
|
1598 | .Ve |
|
|
1599 | .PP |
|
|
1600 | .Vb 2 |
|
|
1601 | \& ... |
|
|
1602 | \& ev_stat passwd; |
|
|
1603 | .Ve |
|
|
1604 | .PP |
|
|
1605 | .Vb 2 |
|
|
1606 | \& ev_stat_init (&passwd, passwd_cb, "/etc/passwd"); |
|
|
1607 | \& ev_stat_start (loop, &passwd); |
|
|
1608 | .Ve |
1198 | .ie n .Sh """ev_idle"" \- when you've got nothing better to do..." |
1609 | .ie n .Sh """ev_idle"" \- when you've got nothing better to do..." |
1199 | .el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do..." |
1610 | .el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do..." |
1200 | .IX Subsection "ev_idle - when you've got nothing better to do..." |
1611 | .IX Subsection "ev_idle - when you've got nothing better to do..." |
1201 | Idle watchers trigger events when there are no other events are pending |
1612 | Idle watchers trigger events when no other events of the same or higher |
1202 | (prepare, check and other idle watchers do not count). That is, as long |
1613 | priority are pending (prepare, check and other idle watchers do not |
1203 | as your process is busy handling sockets or timeouts (or even signals, |
1614 | count). |
1204 | imagine) it will not be triggered. But when your process is idle all idle |
1615 | .PP |
1205 | watchers are being called again and again, once per event loop iteration \- |
1616 | That is, as long as your process is busy handling sockets or timeouts |
|
|
1617 | (or even signals, imagine) of the same or higher priority it will not be |
|
|
1618 | triggered. But when your process is idle (or only lower-priority watchers |
|
|
1619 | are pending), the idle watchers are being called once per event loop |
1206 | until stopped, that is, or your process receives more events and becomes |
1620 | iteration \- until stopped, that is, or your process receives more events |
1207 | busy. |
1621 | and becomes busy again with higher priority stuff. |
1208 | .PP |
1622 | .PP |
1209 | The most noteworthy effect is that as long as any idle watchers are |
1623 | The most noteworthy effect is that as long as any idle watchers are |
1210 | active, the process will not block when waiting for new events. |
1624 | active, the process will not block when waiting for new events. |
1211 | .PP |
1625 | .PP |
1212 | Apart from keeping your process non-blocking (which is a useful |
1626 | Apart from keeping your process non-blocking (which is a useful |
1213 | effect on its own sometimes), idle watchers are a good place to do |
1627 | effect on its own sometimes), idle watchers are a good place to do |
1214 | \&\*(L"pseudo\-background processing\*(R", or delay processing stuff to after the |
1628 | \&\*(L"pseudo\-background processing\*(R", or delay processing stuff to after the |
1215 | event loop has handled all outstanding events. |
1629 | event loop has handled all outstanding events. |
|
|
1630 | .PP |
|
|
1631 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1632 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1216 | .IP "ev_idle_init (ev_signal *, callback)" 4 |
1633 | .IP "ev_idle_init (ev_signal *, callback)" 4 |
1217 | .IX Item "ev_idle_init (ev_signal *, callback)" |
1634 | .IX Item "ev_idle_init (ev_signal *, callback)" |
1218 | Initialises and configures the idle watcher \- it has no parameters of any |
1635 | Initialises and configures the idle watcher \- it has no parameters of any |
1219 | kind. There is a \f(CW\*(C`ev_idle_set\*(C'\fR macro, but using it is utterly pointless, |
1636 | kind. There is a \f(CW\*(C`ev_idle_set\*(C'\fR macro, but using it is utterly pointless, |
1220 | believe me. |
1637 | believe me. |
1221 | .PP |
1638 | .PP |
1222 | Example: dynamically allocate an \f(CW\*(C`ev_idle\*(C'\fR, start it, and in the |
1639 | Example: Dynamically allocate an \f(CW\*(C`ev_idle\*(C'\fR watcher, start it, and in the |
1223 | callback, free it. Alos, use no error checking, as usual. |
1640 | callback, free it. Also, use no error checking, as usual. |
1224 | .PP |
1641 | .PP |
1225 | .Vb 7 |
1642 | .Vb 7 |
1226 | \& static void |
1643 | \& static void |
1227 | \& idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
1644 | \& idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
1228 | \& { |
1645 | \& { |
… | |
… | |
1242 | .IX Subsection "ev_prepare and ev_check - customise your event loop!" |
1659 | .IX Subsection "ev_prepare and ev_check - customise your event loop!" |
1243 | Prepare and check watchers are usually (but not always) used in tandem: |
1660 | Prepare and check watchers are usually (but not always) used in tandem: |
1244 | prepare watchers get invoked before the process blocks and check watchers |
1661 | prepare watchers get invoked before the process blocks and check watchers |
1245 | afterwards. |
1662 | afterwards. |
1246 | .PP |
1663 | .PP |
|
|
1664 | You \fImust not\fR call \f(CW\*(C`ev_loop\*(C'\fR or similar functions that enter |
|
|
1665 | the current event loop from either \f(CW\*(C`ev_prepare\*(C'\fR or \f(CW\*(C`ev_check\*(C'\fR |
|
|
1666 | watchers. Other loops than the current one are fine, however. The |
|
|
1667 | rationale behind this is that you do not need to check for recursion in |
|
|
1668 | those watchers, i.e. the sequence will always be \f(CW\*(C`ev_prepare\*(C'\fR, blocking, |
|
|
1669 | \&\f(CW\*(C`ev_check\*(C'\fR so if you have one watcher of each kind they will always be |
|
|
1670 | called in pairs bracketing the blocking call. |
|
|
1671 | .PP |
1247 | Their main purpose is to integrate other event mechanisms into libev and |
1672 | Their main purpose is to integrate other event mechanisms into libev and |
1248 | their use is somewhat advanced. This could be used, for example, to track |
1673 | their use is somewhat advanced. This could be used, for example, to track |
1249 | variable changes, implement your own watchers, integrate net-snmp or a |
1674 | variable changes, implement your own watchers, integrate net-snmp or a |
1250 | coroutine library and lots more. |
1675 | coroutine library and lots more. They are also occasionally useful if |
|
|
1676 | you cache some data and want to flush it before blocking (for example, |
|
|
1677 | in X programs you might want to do an \f(CW\*(C`XFlush ()\*(C'\fR in an \f(CW\*(C`ev_prepare\*(C'\fR |
|
|
1678 | watcher). |
1251 | .PP |
1679 | .PP |
1252 | This is done by examining in each prepare call which file descriptors need |
1680 | This is done by examining in each prepare call which file descriptors need |
1253 | to be watched by the other library, registering \f(CW\*(C`ev_io\*(C'\fR watchers for |
1681 | to be watched by the other library, registering \f(CW\*(C`ev_io\*(C'\fR watchers for |
1254 | them and starting an \f(CW\*(C`ev_timer\*(C'\fR watcher for any timeouts (many libraries |
1682 | them and starting an \f(CW\*(C`ev_timer\*(C'\fR watcher for any timeouts (many libraries |
1255 | provide just this functionality). Then, in the check watcher you check for |
1683 | provide just this functionality). Then, in the check watcher you check for |
… | |
… | |
1264 | are ready to run (it's actually more complicated: it only runs coroutines |
1692 | are ready to run (it's actually more complicated: it only runs coroutines |
1265 | with priority higher than or equal to the event loop and one coroutine |
1693 | with priority higher than or equal to the event loop and one coroutine |
1266 | of lower priority, but only once, using idle watchers to keep the event |
1694 | of lower priority, but only once, using idle watchers to keep the event |
1267 | loop from blocking if lower-priority coroutines are active, thus mapping |
1695 | loop from blocking if lower-priority coroutines are active, thus mapping |
1268 | low-priority coroutines to idle/background tasks). |
1696 | low-priority coroutines to idle/background tasks). |
|
|
1697 | .PP |
|
|
1698 | It is recommended to give \f(CW\*(C`ev_check\*(C'\fR watchers highest (\f(CW\*(C`EV_MAXPRI\*(C'\fR) |
|
|
1699 | priority, to ensure that they are being run before any other watchers |
|
|
1700 | after the poll. Also, \f(CW\*(C`ev_check\*(C'\fR watchers (and \f(CW\*(C`ev_prepare\*(C'\fR watchers, |
|
|
1701 | too) should not activate (\*(L"feed\*(R") events into libev. While libev fully |
|
|
1702 | supports this, they will be called before other \f(CW\*(C`ev_check\*(C'\fR watchers did |
|
|
1703 | their job. As \f(CW\*(C`ev_check\*(C'\fR watchers are often used to embed other event |
|
|
1704 | loops those other event loops might be in an unusable state until their |
|
|
1705 | \&\f(CW\*(C`ev_check\*(C'\fR watcher ran (always remind yourself to coexist peacefully with |
|
|
1706 | others). |
|
|
1707 | .PP |
|
|
1708 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1709 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1269 | .IP "ev_prepare_init (ev_prepare *, callback)" 4 |
1710 | .IP "ev_prepare_init (ev_prepare *, callback)" 4 |
1270 | .IX Item "ev_prepare_init (ev_prepare *, callback)" |
1711 | .IX Item "ev_prepare_init (ev_prepare *, callback)" |
1271 | .PD 0 |
1712 | .PD 0 |
1272 | .IP "ev_check_init (ev_check *, callback)" 4 |
1713 | .IP "ev_check_init (ev_check *, callback)" 4 |
1273 | .IX Item "ev_check_init (ev_check *, callback)" |
1714 | .IX Item "ev_check_init (ev_check *, callback)" |
1274 | .PD |
1715 | .PD |
1275 | Initialises and configures the prepare or check watcher \- they have no |
1716 | Initialises and configures the prepare or check watcher \- they have no |
1276 | parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR |
1717 | parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR |
1277 | macros, but using them is utterly, utterly and completely pointless. |
1718 | macros, but using them is utterly, utterly and completely pointless. |
1278 | .PP |
1719 | .PP |
1279 | Example: *TODO*. |
1720 | There are a number of principal ways to embed other event loops or modules |
|
|
1721 | into libev. Here are some ideas on how to include libadns into libev |
|
|
1722 | (there is a Perl module named \f(CW\*(C`EV::ADNS\*(C'\fR that does this, which you could |
|
|
1723 | use for an actually working example. Another Perl module named \f(CW\*(C`EV::Glib\*(C'\fR |
|
|
1724 | embeds a Glib main context into libev, and finally, \f(CW\*(C`Glib::EV\*(C'\fR embeds \s-1EV\s0 |
|
|
1725 | into the Glib event loop). |
|
|
1726 | .PP |
|
|
1727 | Method 1: Add \s-1IO\s0 watchers and a timeout watcher in a prepare handler, |
|
|
1728 | and in a check watcher, destroy them and call into libadns. What follows |
|
|
1729 | is pseudo-code only of course. This requires you to either use a low |
|
|
1730 | priority for the check watcher or use \f(CW\*(C`ev_clear_pending\*(C'\fR explicitly, as |
|
|
1731 | the callbacks for the IO/timeout watchers might not have been called yet. |
|
|
1732 | .PP |
|
|
1733 | .Vb 2 |
|
|
1734 | \& static ev_io iow [nfd]; |
|
|
1735 | \& static ev_timer tw; |
|
|
1736 | .Ve |
|
|
1737 | .PP |
|
|
1738 | .Vb 4 |
|
|
1739 | \& static void |
|
|
1740 | \& io_cb (ev_loop *loop, ev_io *w, int revents) |
|
|
1741 | \& { |
|
|
1742 | \& } |
|
|
1743 | .Ve |
|
|
1744 | .PP |
|
|
1745 | .Vb 8 |
|
|
1746 | \& // create io watchers for each fd and a timer before blocking |
|
|
1747 | \& static void |
|
|
1748 | \& adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
|
|
1749 | \& { |
|
|
1750 | \& int timeout = 3600000; |
|
|
1751 | \& struct pollfd fds [nfd]; |
|
|
1752 | \& // actual code will need to loop here and realloc etc. |
|
|
1753 | \& adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
|
|
1754 | .Ve |
|
|
1755 | .PP |
|
|
1756 | .Vb 3 |
|
|
1757 | \& /* the callback is illegal, but won't be called as we stop during check */ |
|
|
1758 | \& ev_timer_init (&tw, 0, timeout * 1e-3); |
|
|
1759 | \& ev_timer_start (loop, &tw); |
|
|
1760 | .Ve |
|
|
1761 | .PP |
|
|
1762 | .Vb 6 |
|
|
1763 | \& // create one ev_io per pollfd |
|
|
1764 | \& for (int i = 0; i < nfd; ++i) |
|
|
1765 | \& { |
|
|
1766 | \& ev_io_init (iow + i, io_cb, fds [i].fd, |
|
|
1767 | \& ((fds [i].events & POLLIN ? EV_READ : 0) |
|
|
1768 | \& | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
|
|
1769 | .Ve |
|
|
1770 | .PP |
|
|
1771 | .Vb 4 |
|
|
1772 | \& fds [i].revents = 0; |
|
|
1773 | \& ev_io_start (loop, iow + i); |
|
|
1774 | \& } |
|
|
1775 | \& } |
|
|
1776 | .Ve |
|
|
1777 | .PP |
|
|
1778 | .Vb 5 |
|
|
1779 | \& // stop all watchers after blocking |
|
|
1780 | \& static void |
|
|
1781 | \& adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
|
|
1782 | \& { |
|
|
1783 | \& ev_timer_stop (loop, &tw); |
|
|
1784 | .Ve |
|
|
1785 | .PP |
|
|
1786 | .Vb 8 |
|
|
1787 | \& for (int i = 0; i < nfd; ++i) |
|
|
1788 | \& { |
|
|
1789 | \& // set the relevant poll flags |
|
|
1790 | \& // could also call adns_processreadable etc. here |
|
|
1791 | \& struct pollfd *fd = fds + i; |
|
|
1792 | \& int revents = ev_clear_pending (iow + i); |
|
|
1793 | \& if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
|
|
1794 | \& if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
|
|
1795 | .Ve |
|
|
1796 | .PP |
|
|
1797 | .Vb 3 |
|
|
1798 | \& // now stop the watcher |
|
|
1799 | \& ev_io_stop (loop, iow + i); |
|
|
1800 | \& } |
|
|
1801 | .Ve |
|
|
1802 | .PP |
|
|
1803 | .Vb 2 |
|
|
1804 | \& adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
|
|
1805 | \& } |
|
|
1806 | .Ve |
|
|
1807 | .PP |
|
|
1808 | Method 2: This would be just like method 1, but you run \f(CW\*(C`adns_afterpoll\*(C'\fR |
|
|
1809 | in the prepare watcher and would dispose of the check watcher. |
|
|
1810 | .PP |
|
|
1811 | Method 3: If the module to be embedded supports explicit event |
|
|
1812 | notification (adns does), you can also make use of the actual watcher |
|
|
1813 | callbacks, and only destroy/create the watchers in the prepare watcher. |
|
|
1814 | .PP |
|
|
1815 | .Vb 5 |
|
|
1816 | \& static void |
|
|
1817 | \& timer_cb (EV_P_ ev_timer *w, int revents) |
|
|
1818 | \& { |
|
|
1819 | \& adns_state ads = (adns_state)w->data; |
|
|
1820 | \& update_now (EV_A); |
|
|
1821 | .Ve |
|
|
1822 | .PP |
|
|
1823 | .Vb 2 |
|
|
1824 | \& adns_processtimeouts (ads, &tv_now); |
|
|
1825 | \& } |
|
|
1826 | .Ve |
|
|
1827 | .PP |
|
|
1828 | .Vb 5 |
|
|
1829 | \& static void |
|
|
1830 | \& io_cb (EV_P_ ev_io *w, int revents) |
|
|
1831 | \& { |
|
|
1832 | \& adns_state ads = (adns_state)w->data; |
|
|
1833 | \& update_now (EV_A); |
|
|
1834 | .Ve |
|
|
1835 | .PP |
|
|
1836 | .Vb 3 |
|
|
1837 | \& if (revents & EV_READ ) adns_processreadable (ads, w->fd, &tv_now); |
|
|
1838 | \& if (revents & EV_WRITE) adns_processwriteable (ads, w->fd, &tv_now); |
|
|
1839 | \& } |
|
|
1840 | .Ve |
|
|
1841 | .PP |
|
|
1842 | .Vb 1 |
|
|
1843 | \& // do not ever call adns_afterpoll |
|
|
1844 | .Ve |
|
|
1845 | .PP |
|
|
1846 | Method 4: Do not use a prepare or check watcher because the module you |
|
|
1847 | want to embed is too inflexible to support it. Instead, youc na override |
|
|
1848 | their poll function. The drawback with this solution is that the main |
|
|
1849 | loop is now no longer controllable by \s-1EV\s0. The \f(CW\*(C`Glib::EV\*(C'\fR module does |
|
|
1850 | this. |
|
|
1851 | .PP |
|
|
1852 | .Vb 4 |
|
|
1853 | \& static gint |
|
|
1854 | \& event_poll_func (GPollFD *fds, guint nfds, gint timeout) |
|
|
1855 | \& { |
|
|
1856 | \& int got_events = 0; |
|
|
1857 | .Ve |
|
|
1858 | .PP |
|
|
1859 | .Vb 2 |
|
|
1860 | \& for (n = 0; n < nfds; ++n) |
|
|
1861 | \& // create/start io watcher that sets the relevant bits in fds[n] and increment got_events |
|
|
1862 | .Ve |
|
|
1863 | .PP |
|
|
1864 | .Vb 2 |
|
|
1865 | \& if (timeout >= 0) |
|
|
1866 | \& // create/start timer |
|
|
1867 | .Ve |
|
|
1868 | .PP |
|
|
1869 | .Vb 2 |
|
|
1870 | \& // poll |
|
|
1871 | \& ev_loop (EV_A_ 0); |
|
|
1872 | .Ve |
|
|
1873 | .PP |
|
|
1874 | .Vb 3 |
|
|
1875 | \& // stop timer again |
|
|
1876 | \& if (timeout >= 0) |
|
|
1877 | \& ev_timer_stop (EV_A_ &to); |
|
|
1878 | .Ve |
|
|
1879 | .PP |
|
|
1880 | .Vb 3 |
|
|
1881 | \& // stop io watchers again - their callbacks should have set |
|
|
1882 | \& for (n = 0; n < nfds; ++n) |
|
|
1883 | \& ev_io_stop (EV_A_ iow [n]); |
|
|
1884 | .Ve |
|
|
1885 | .PP |
|
|
1886 | .Vb 2 |
|
|
1887 | \& return got_events; |
|
|
1888 | \& } |
|
|
1889 | .Ve |
1280 | .ie n .Sh """ev_embed"" \- when one backend isn't enough..." |
1890 | .ie n .Sh """ev_embed"" \- when one backend isn't enough..." |
1281 | .el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..." |
1891 | .el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..." |
1282 | .IX Subsection "ev_embed - when one backend isn't enough..." |
1892 | .IX Subsection "ev_embed - when one backend isn't enough..." |
1283 | This is a rather advanced watcher type that lets you embed one event loop |
1893 | This is a rather advanced watcher type that lets you embed one event loop |
1284 | into another (currently only \f(CW\*(C`ev_io\*(C'\fR events are supported in the embedded |
1894 | into another (currently only \f(CW\*(C`ev_io\*(C'\fR events are supported in the embedded |
… | |
… | |
1351 | \& ev_embed_start (loop_hi, &embed); |
1961 | \& ev_embed_start (loop_hi, &embed); |
1352 | \& } |
1962 | \& } |
1353 | \& else |
1963 | \& else |
1354 | \& loop_lo = loop_hi; |
1964 | \& loop_lo = loop_hi; |
1355 | .Ve |
1965 | .Ve |
|
|
1966 | .PP |
|
|
1967 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1968 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1356 | .IP "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
1969 | .IP "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
1357 | .IX Item "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" |
1970 | .IX Item "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" |
1358 | .PD 0 |
1971 | .PD 0 |
1359 | .IP "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
1972 | .IP "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
1360 | .IX Item "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" |
1973 | .IX Item "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" |
… | |
… | |
1367 | .IP "ev_embed_sweep (loop, ev_embed *)" 4 |
1980 | .IP "ev_embed_sweep (loop, ev_embed *)" 4 |
1368 | .IX Item "ev_embed_sweep (loop, ev_embed *)" |
1981 | .IX Item "ev_embed_sweep (loop, ev_embed *)" |
1369 | Make a single, non-blocking sweep over the embedded loop. This works |
1982 | Make a single, non-blocking sweep over the embedded loop. This works |
1370 | similarly to \f(CW\*(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\*(C'\fR, but in the most |
1983 | similarly to \f(CW\*(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\*(C'\fR, but in the most |
1371 | apropriate way for embedded loops. |
1984 | apropriate way for embedded loops. |
|
|
1985 | .IP "struct ev_loop *loop [read\-only]" 4 |
|
|
1986 | .IX Item "struct ev_loop *loop [read-only]" |
|
|
1987 | The embedded event loop. |
|
|
1988 | .ie n .Sh """ev_fork"" \- the audacity to resume the event loop after a fork" |
|
|
1989 | .el .Sh "\f(CWev_fork\fP \- the audacity to resume the event loop after a fork" |
|
|
1990 | .IX Subsection "ev_fork - the audacity to resume the event loop after a fork" |
|
|
1991 | Fork watchers are called when a \f(CW\*(C`fork ()\*(C'\fR was detected (usually because |
|
|
1992 | whoever is a good citizen cared to tell libev about it by calling |
|
|
1993 | \&\f(CW\*(C`ev_default_fork\*(C'\fR or \f(CW\*(C`ev_loop_fork\*(C'\fR). The invocation is done before the |
|
|
1994 | event loop blocks next and before \f(CW\*(C`ev_check\*(C'\fR watchers are being called, |
|
|
1995 | and only in the child after the fork. If whoever good citizen calling |
|
|
1996 | \&\f(CW\*(C`ev_default_fork\*(C'\fR cheats and calls it in the wrong process, the fork |
|
|
1997 | handlers will be invoked, too, of course. |
|
|
1998 | .PP |
|
|
1999 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
2000 | .IX Subsection "Watcher-Specific Functions and Data Members" |
|
|
2001 | .IP "ev_fork_init (ev_signal *, callback)" 4 |
|
|
2002 | .IX Item "ev_fork_init (ev_signal *, callback)" |
|
|
2003 | Initialises and configures the fork watcher \- it has no parameters of any |
|
|
2004 | kind. There is a \f(CW\*(C`ev_fork_set\*(C'\fR macro, but using it is utterly pointless, |
|
|
2005 | believe me. |
1372 | .SH "OTHER FUNCTIONS" |
2006 | .SH "OTHER FUNCTIONS" |
1373 | .IX Header "OTHER FUNCTIONS" |
2007 | .IX Header "OTHER FUNCTIONS" |
1374 | There are some other functions of possible interest. Described. Here. Now. |
2008 | There are some other functions of possible interest. Described. Here. Now. |
1375 | .IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4 |
2009 | .IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4 |
1376 | .IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" |
2010 | .IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" |
… | |
… | |
1448 | .PP |
2082 | .PP |
1449 | .Vb 1 |
2083 | .Vb 1 |
1450 | \& #include <ev++.h> |
2084 | \& #include <ev++.h> |
1451 | .Ve |
2085 | .Ve |
1452 | .PP |
2086 | .PP |
1453 | (it is not installed by default). This automatically includes \fIev.h\fR |
2087 | This automatically includes \fIev.h\fR and puts all of its definitions (many |
1454 | and puts all of its definitions (many of them macros) into the global |
2088 | of them macros) into the global namespace. All \*(C+ specific things are |
1455 | namespace. All \*(C+ specific things are put into the \f(CW\*(C`ev\*(C'\fR namespace. |
2089 | put into the \f(CW\*(C`ev\*(C'\fR namespace. It should support all the same embedding |
|
|
2090 | options as \fIev.h\fR, most notably \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. |
1456 | .PP |
2091 | .PP |
1457 | It should support all the same embedding options as \fIev.h\fR, most notably |
2092 | Care has been taken to keep the overhead low. The only data member the \*(C+ |
1458 | \&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. |
2093 | classes add (compared to plain C\-style watchers) is the event loop pointer |
|
|
2094 | that the watcher is associated with (or no additional members at all if |
|
|
2095 | you disable \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR when embedding libev). |
|
|
2096 | .PP |
|
|
2097 | Currently, functions, and static and non-static member functions can be |
|
|
2098 | used as callbacks. Other types should be easy to add as long as they only |
|
|
2099 | need one additional pointer for context. If you need support for other |
|
|
2100 | types of functors please contact the author (preferably after implementing |
|
|
2101 | it). |
1459 | .PP |
2102 | .PP |
1460 | Here is a list of things available in the \f(CW\*(C`ev\*(C'\fR namespace: |
2103 | Here is a list of things available in the \f(CW\*(C`ev\*(C'\fR namespace: |
1461 | .ie n .IP """ev::READ""\fR, \f(CW""ev::WRITE"" etc." 4 |
2104 | .ie n .IP """ev::READ""\fR, \f(CW""ev::WRITE"" etc." 4 |
1462 | .el .IP "\f(CWev::READ\fR, \f(CWev::WRITE\fR etc." 4 |
2105 | .el .IP "\f(CWev::READ\fR, \f(CWev::WRITE\fR etc." 4 |
1463 | .IX Item "ev::READ, ev::WRITE etc." |
2106 | .IX Item "ev::READ, ev::WRITE etc." |
… | |
… | |
1475 | which is called \f(CW\*(C`ev::sig\*(C'\fR to avoid clashes with the \f(CW\*(C`signal\*(C'\fR macro |
2118 | which is called \f(CW\*(C`ev::sig\*(C'\fR to avoid clashes with the \f(CW\*(C`signal\*(C'\fR macro |
1476 | defines by many implementations. |
2119 | defines by many implementations. |
1477 | .Sp |
2120 | .Sp |
1478 | All of those classes have these methods: |
2121 | All of those classes have these methods: |
1479 | .RS 4 |
2122 | .RS 4 |
1480 | .IP "ev::TYPE::TYPE (object *, object::method *)" 4 |
2123 | .IP "ev::TYPE::TYPE ()" 4 |
1481 | .IX Item "ev::TYPE::TYPE (object *, object::method *)" |
2124 | .IX Item "ev::TYPE::TYPE ()" |
1482 | .PD 0 |
2125 | .PD 0 |
1483 | .IP "ev::TYPE::TYPE (object *, object::method *, struct ev_loop *)" 4 |
2126 | .IP "ev::TYPE::TYPE (struct ev_loop *)" 4 |
1484 | .IX Item "ev::TYPE::TYPE (object *, object::method *, struct ev_loop *)" |
2127 | .IX Item "ev::TYPE::TYPE (struct ev_loop *)" |
1485 | .IP "ev::TYPE::~TYPE" 4 |
2128 | .IP "ev::TYPE::~TYPE" 4 |
1486 | .IX Item "ev::TYPE::~TYPE" |
2129 | .IX Item "ev::TYPE::~TYPE" |
1487 | .PD |
2130 | .PD |
1488 | The constructor takes a pointer to an object and a method pointer to |
2131 | The constructor (optionally) takes an event loop to associate the watcher |
1489 | the event handler callback to call in this class. The constructor calls |
2132 | with. If it is omitted, it will use \f(CW\*(C`EV_DEFAULT\*(C'\fR. |
1490 | \&\f(CW\*(C`ev_init\*(C'\fR for you, which means you have to call the \f(CW\*(C`set\*(C'\fR method |
2133 | .Sp |
1491 | before starting it. If you do not specify a loop then the constructor |
2134 | The constructor calls \f(CW\*(C`ev_init\*(C'\fR for you, which means you have to call the |
1492 | automatically associates the default loop with this watcher. |
2135 | \&\f(CW\*(C`set\*(C'\fR method before starting it. |
|
|
2136 | .Sp |
|
|
2137 | It will not set a callback, however: You have to call the templated \f(CW\*(C`set\*(C'\fR |
|
|
2138 | method to set a callback before you can start the watcher. |
|
|
2139 | .Sp |
|
|
2140 | (The reason why you have to use a method is a limitation in \*(C+ which does |
|
|
2141 | not allow explicit template arguments for constructors). |
1493 | .Sp |
2142 | .Sp |
1494 | The destructor automatically stops the watcher if it is active. |
2143 | The destructor automatically stops the watcher if it is active. |
|
|
2144 | .IP "w\->set<class, &class::method> (object *)" 4 |
|
|
2145 | .IX Item "w->set<class, &class::method> (object *)" |
|
|
2146 | This method sets the callback method to call. The method has to have a |
|
|
2147 | signature of \f(CW\*(C`void (*)(ev_TYPE &, int)\*(C'\fR, it receives the watcher as |
|
|
2148 | first argument and the \f(CW\*(C`revents\*(C'\fR as second. The object must be given as |
|
|
2149 | parameter and is stored in the \f(CW\*(C`data\*(C'\fR member of the watcher. |
|
|
2150 | .Sp |
|
|
2151 | This method synthesizes efficient thunking code to call your method from |
|
|
2152 | the C callback that libev requires. If your compiler can inline your |
|
|
2153 | callback (i.e. it is visible to it at the place of the \f(CW\*(C`set\*(C'\fR call and |
|
|
2154 | your compiler is good :), then the method will be fully inlined into the |
|
|
2155 | thunking function, making it as fast as a direct C callback. |
|
|
2156 | .Sp |
|
|
2157 | Example: simple class declaration and watcher initialisation |
|
|
2158 | .Sp |
|
|
2159 | .Vb 4 |
|
|
2160 | \& struct myclass |
|
|
2161 | \& { |
|
|
2162 | \& void io_cb (ev::io &w, int revents) { } |
|
|
2163 | \& } |
|
|
2164 | .Ve |
|
|
2165 | .Sp |
|
|
2166 | .Vb 3 |
|
|
2167 | \& myclass obj; |
|
|
2168 | \& ev::io iow; |
|
|
2169 | \& iow.set <myclass, &myclass::io_cb> (&obj); |
|
|
2170 | .Ve |
|
|
2171 | .IP "w\->set<function> (void *data = 0)" 4 |
|
|
2172 | .IX Item "w->set<function> (void *data = 0)" |
|
|
2173 | Also sets a callback, but uses a static method or plain function as |
|
|
2174 | callback. The optional \f(CW\*(C`data\*(C'\fR argument will be stored in the watcher's |
|
|
2175 | \&\f(CW\*(C`data\*(C'\fR member and is free for you to use. |
|
|
2176 | .Sp |
|
|
2177 | The prototype of the \f(CW\*(C`function\*(C'\fR must be \f(CW\*(C`void (*)(ev::TYPE &w, int)\*(C'\fR. |
|
|
2178 | .Sp |
|
|
2179 | See the method\-\f(CW\*(C`set\*(C'\fR above for more details. |
|
|
2180 | .Sp |
|
|
2181 | Example: |
|
|
2182 | .Sp |
|
|
2183 | .Vb 2 |
|
|
2184 | \& static void io_cb (ev::io &w, int revents) { } |
|
|
2185 | \& iow.set <io_cb> (); |
|
|
2186 | .Ve |
1495 | .IP "w\->set (struct ev_loop *)" 4 |
2187 | .IP "w\->set (struct ev_loop *)" 4 |
1496 | .IX Item "w->set (struct ev_loop *)" |
2188 | .IX Item "w->set (struct ev_loop *)" |
1497 | Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only |
2189 | Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only |
1498 | do this when the watcher is inactive (and not pending either). |
2190 | do this when the watcher is inactive (and not pending either). |
1499 | .IP "w\->set ([args])" 4 |
2191 | .IP "w\->set ([args])" 4 |
1500 | .IX Item "w->set ([args])" |
2192 | .IX Item "w->set ([args])" |
1501 | Basically the same as \f(CW\*(C`ev_TYPE_set\*(C'\fR, with the same args. Must be |
2193 | Basically the same as \f(CW\*(C`ev_TYPE_set\*(C'\fR, with the same args. Must be |
1502 | called at least once. Unlike the C counterpart, an active watcher gets |
2194 | called at least once. Unlike the C counterpart, an active watcher gets |
1503 | automatically stopped and restarted. |
2195 | automatically stopped and restarted when reconfiguring it with this |
|
|
2196 | method. |
1504 | .IP "w\->start ()" 4 |
2197 | .IP "w\->start ()" 4 |
1505 | .IX Item "w->start ()" |
2198 | .IX Item "w->start ()" |
1506 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument as the |
2199 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument, as the |
1507 | constructor already takes the loop. |
2200 | constructor already stores the event loop. |
1508 | .IP "w\->stop ()" 4 |
2201 | .IP "w\->stop ()" 4 |
1509 | .IX Item "w->stop ()" |
2202 | .IX Item "w->stop ()" |
1510 | Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument. |
2203 | Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument. |
1511 | .ie n .IP "w\->again () ""ev::timer""\fR, \f(CW""ev::periodic"" only" 4 |
2204 | .ie n .IP "w\->again () ""ev::timer""\fR, \f(CW""ev::periodic"" only" 4 |
1512 | .el .IP "w\->again () \f(CWev::timer\fR, \f(CWev::periodic\fR only" 4 |
2205 | .el .IP "w\->again () \f(CWev::timer\fR, \f(CWev::periodic\fR only" 4 |
… | |
… | |
1515 | \&\f(CW\*(C`ev_TYPE_again\*(C'\fR function. |
2208 | \&\f(CW\*(C`ev_TYPE_again\*(C'\fR function. |
1516 | .ie n .IP "w\->sweep () ""ev::embed"" only" 4 |
2209 | .ie n .IP "w\->sweep () ""ev::embed"" only" 4 |
1517 | .el .IP "w\->sweep () \f(CWev::embed\fR only" 4 |
2210 | .el .IP "w\->sweep () \f(CWev::embed\fR only" 4 |
1518 | .IX Item "w->sweep () ev::embed only" |
2211 | .IX Item "w->sweep () ev::embed only" |
1519 | Invokes \f(CW\*(C`ev_embed_sweep\*(C'\fR. |
2212 | Invokes \f(CW\*(C`ev_embed_sweep\*(C'\fR. |
|
|
2213 | .ie n .IP "w\->update () ""ev::stat"" only" 4 |
|
|
2214 | .el .IP "w\->update () \f(CWev::stat\fR only" 4 |
|
|
2215 | .IX Item "w->update () ev::stat only" |
|
|
2216 | Invokes \f(CW\*(C`ev_stat_stat\*(C'\fR. |
1520 | .RE |
2217 | .RE |
1521 | .RS 4 |
2218 | .RS 4 |
1522 | .RE |
2219 | .RE |
1523 | .PP |
2220 | .PP |
1524 | Example: Define a class with an \s-1IO\s0 and idle watcher, start one of them in |
2221 | Example: Define a class with an \s-1IO\s0 and idle watcher, start one of them in |
… | |
… | |
1534 | .Vb 2 |
2231 | .Vb 2 |
1535 | \& myclass (); |
2232 | \& myclass (); |
1536 | \& } |
2233 | \& } |
1537 | .Ve |
2234 | .Ve |
1538 | .PP |
2235 | .PP |
1539 | .Vb 6 |
2236 | .Vb 4 |
1540 | \& myclass::myclass (int fd) |
2237 | \& myclass::myclass (int fd) |
1541 | \& : io (this, &myclass::io_cb), |
|
|
1542 | \& idle (this, &myclass::idle_cb) |
|
|
1543 | \& { |
2238 | \& { |
|
|
2239 | \& io .set <myclass, &myclass::io_cb > (this); |
|
|
2240 | \& idle.set <myclass, &myclass::idle_cb> (this); |
|
|
2241 | .Ve |
|
|
2242 | .PP |
|
|
2243 | .Vb 2 |
1544 | \& io.start (fd, ev::READ); |
2244 | \& io.start (fd, ev::READ); |
1545 | \& } |
2245 | \& } |
|
|
2246 | .Ve |
|
|
2247 | .SH "MACRO MAGIC" |
|
|
2248 | .IX Header "MACRO MAGIC" |
|
|
2249 | Libev can be compiled with a variety of options, the most fundemantal is |
|
|
2250 | \&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines whether (most) functions and |
|
|
2251 | callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument. |
|
|
2252 | .PP |
|
|
2253 | To make it easier to write programs that cope with either variant, the |
|
|
2254 | following macros are defined: |
|
|
2255 | .ie n .IP """EV_A""\fR, \f(CW""EV_A_""" 4 |
|
|
2256 | .el .IP "\f(CWEV_A\fR, \f(CWEV_A_\fR" 4 |
|
|
2257 | .IX Item "EV_A, EV_A_" |
|
|
2258 | This provides the loop \fIargument\fR for functions, if one is required (\*(L"ev |
|
|
2259 | loop argument\*(R"). The \f(CW\*(C`EV_A\*(C'\fR form is used when this is the sole argument, |
|
|
2260 | \&\f(CW\*(C`EV_A_\*(C'\fR is used when other arguments are following. Example: |
|
|
2261 | .Sp |
|
|
2262 | .Vb 3 |
|
|
2263 | \& ev_unref (EV_A); |
|
|
2264 | \& ev_timer_add (EV_A_ watcher); |
|
|
2265 | \& ev_loop (EV_A_ 0); |
|
|
2266 | .Ve |
|
|
2267 | .Sp |
|
|
2268 | It assumes the variable \f(CW\*(C`loop\*(C'\fR of type \f(CW\*(C`struct ev_loop *\*(C'\fR is in scope, |
|
|
2269 | which is often provided by the following macro. |
|
|
2270 | .ie n .IP """EV_P""\fR, \f(CW""EV_P_""" 4 |
|
|
2271 | .el .IP "\f(CWEV_P\fR, \f(CWEV_P_\fR" 4 |
|
|
2272 | .IX Item "EV_P, EV_P_" |
|
|
2273 | This provides the loop \fIparameter\fR for functions, if one is required (\*(L"ev |
|
|
2274 | loop parameter\*(R"). The \f(CW\*(C`EV_P\*(C'\fR form is used when this is the sole parameter, |
|
|
2275 | \&\f(CW\*(C`EV_P_\*(C'\fR is used when other parameters are following. Example: |
|
|
2276 | .Sp |
|
|
2277 | .Vb 2 |
|
|
2278 | \& // this is how ev_unref is being declared |
|
|
2279 | \& static void ev_unref (EV_P); |
|
|
2280 | .Ve |
|
|
2281 | .Sp |
|
|
2282 | .Vb 2 |
|
|
2283 | \& // this is how you can declare your typical callback |
|
|
2284 | \& static void cb (EV_P_ ev_timer *w, int revents) |
|
|
2285 | .Ve |
|
|
2286 | .Sp |
|
|
2287 | It declares a parameter \f(CW\*(C`loop\*(C'\fR of type \f(CW\*(C`struct ev_loop *\*(C'\fR, quite |
|
|
2288 | suitable for use with \f(CW\*(C`EV_A\*(C'\fR. |
|
|
2289 | .ie n .IP """EV_DEFAULT""\fR, \f(CW""EV_DEFAULT_""" 4 |
|
|
2290 | .el .IP "\f(CWEV_DEFAULT\fR, \f(CWEV_DEFAULT_\fR" 4 |
|
|
2291 | .IX Item "EV_DEFAULT, EV_DEFAULT_" |
|
|
2292 | Similar to the other two macros, this gives you the value of the default |
|
|
2293 | loop, if multiple loops are supported (\*(L"ev loop default\*(R"). |
|
|
2294 | .PP |
|
|
2295 | Example: Declare and initialise a check watcher, utilising the above |
|
|
2296 | macros so it will work regardless of whether multiple loops are supported |
|
|
2297 | or not. |
|
|
2298 | .PP |
|
|
2299 | .Vb 5 |
|
|
2300 | \& static void |
|
|
2301 | \& check_cb (EV_P_ ev_timer *w, int revents) |
|
|
2302 | \& { |
|
|
2303 | \& ev_check_stop (EV_A_ w); |
|
|
2304 | \& } |
|
|
2305 | .Ve |
|
|
2306 | .PP |
|
|
2307 | .Vb 4 |
|
|
2308 | \& ev_check check; |
|
|
2309 | \& ev_check_init (&check, check_cb); |
|
|
2310 | \& ev_check_start (EV_DEFAULT_ &check); |
|
|
2311 | \& ev_loop (EV_DEFAULT_ 0); |
1546 | .Ve |
2312 | .Ve |
1547 | .SH "EMBEDDING" |
2313 | .SH "EMBEDDING" |
1548 | .IX Header "EMBEDDING" |
2314 | .IX Header "EMBEDDING" |
1549 | Libev can (and often is) directly embedded into host |
2315 | Libev can (and often is) directly embedded into host |
1550 | applications. Examples of applications that embed it include the Deliantra |
2316 | applications. Examples of applications that embed it include the Deliantra |
… | |
… | |
1599 | .Vb 1 |
2365 | .Vb 1 |
1600 | \& ev_win32.c required on win32 platforms only |
2366 | \& ev_win32.c required on win32 platforms only |
1601 | .Ve |
2367 | .Ve |
1602 | .PP |
2368 | .PP |
1603 | .Vb 5 |
2369 | .Vb 5 |
1604 | \& ev_select.c only when select backend is enabled (which is is by default) |
2370 | \& ev_select.c only when select backend is enabled (which is enabled by default) |
1605 | \& ev_poll.c only when poll backend is enabled (disabled by default) |
2371 | \& ev_poll.c only when poll backend is enabled (disabled by default) |
1606 | \& ev_epoll.c only when the epoll backend is enabled (disabled by default) |
2372 | \& ev_epoll.c only when the epoll backend is enabled (disabled by default) |
1607 | \& ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
2373 | \& ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
1608 | \& ev_port.c only when the solaris port backend is enabled (disabled by default) |
2374 | \& ev_port.c only when the solaris port backend is enabled (disabled by default) |
1609 | .Ve |
2375 | .Ve |
1610 | .PP |
2376 | .PP |
1611 | \&\fIev.c\fR includes the backend files directly when enabled, so you only need |
2377 | \&\fIev.c\fR includes the backend files directly when enabled, so you only need |
1612 | to compile a single file. |
2378 | to compile this single file. |
1613 | .PP |
2379 | .PP |
1614 | \fI\s-1LIBEVENT\s0 \s-1COMPATIBILITY\s0 \s-1API\s0\fR |
2380 | \fI\s-1LIBEVENT\s0 \s-1COMPATIBILITY\s0 \s-1API\s0\fR |
1615 | .IX Subsection "LIBEVENT COMPATIBILITY API" |
2381 | .IX Subsection "LIBEVENT COMPATIBILITY API" |
1616 | .PP |
2382 | .PP |
1617 | To include the libevent compatibility \s-1API\s0, also include: |
2383 | To include the libevent compatibility \s-1API\s0, also include: |
… | |
… | |
1638 | \fI\s-1AUTOCONF\s0 \s-1SUPPORT\s0\fR |
2404 | \fI\s-1AUTOCONF\s0 \s-1SUPPORT\s0\fR |
1639 | .IX Subsection "AUTOCONF SUPPORT" |
2405 | .IX Subsection "AUTOCONF SUPPORT" |
1640 | .PP |
2406 | .PP |
1641 | Instead of using \f(CW\*(C`EV_STANDALONE=1\*(C'\fR and providing your config in |
2407 | Instead of using \f(CW\*(C`EV_STANDALONE=1\*(C'\fR and providing your config in |
1642 | whatever way you want, you can also \f(CW\*(C`m4_include([libev.m4])\*(C'\fR in your |
2408 | whatever way you want, you can also \f(CW\*(C`m4_include([libev.m4])\*(C'\fR in your |
1643 | \&\fIconfigure.ac\fR and leave \f(CW\*(C`EV_STANDALONE\*(C'\fR off. \fIev.c\fR will then include |
2409 | \&\fIconfigure.ac\fR and leave \f(CW\*(C`EV_STANDALONE\*(C'\fR undefined. \fIev.c\fR will then |
1644 | \&\fIconfig.h\fR and configure itself accordingly. |
2410 | include \fIconfig.h\fR and configure itself accordingly. |
1645 | .PP |
2411 | .PP |
1646 | For this of course you need the m4 file: |
2412 | For this of course you need the m4 file: |
1647 | .PP |
2413 | .PP |
1648 | .Vb 1 |
2414 | .Vb 1 |
1649 | \& libev.m4 |
2415 | \& libev.m4 |
… | |
… | |
1730 | otherwise another method will be used as fallback. This is the preferred |
2496 | otherwise another method will be used as fallback. This is the preferred |
1731 | backend for Solaris 10 systems. |
2497 | backend for Solaris 10 systems. |
1732 | .IP "\s-1EV_USE_DEVPOLL\s0" 4 |
2498 | .IP "\s-1EV_USE_DEVPOLL\s0" 4 |
1733 | .IX Item "EV_USE_DEVPOLL" |
2499 | .IX Item "EV_USE_DEVPOLL" |
1734 | reserved for future expansion, works like the \s-1USE\s0 symbols above. |
2500 | reserved for future expansion, works like the \s-1USE\s0 symbols above. |
|
|
2501 | .IP "\s-1EV_USE_INOTIFY\s0" 4 |
|
|
2502 | .IX Item "EV_USE_INOTIFY" |
|
|
2503 | If defined to be \f(CW1\fR, libev will compile in support for the Linux inotify |
|
|
2504 | interface to speed up \f(CW\*(C`ev_stat\*(C'\fR watchers. Its actual availability will |
|
|
2505 | be detected at runtime. |
1735 | .IP "\s-1EV_H\s0" 4 |
2506 | .IP "\s-1EV_H\s0" 4 |
1736 | .IX Item "EV_H" |
2507 | .IX Item "EV_H" |
1737 | The name of the \fIev.h\fR header file used to include it. The default if |
2508 | The name of the \fIev.h\fR header file used to include it. The default if |
1738 | undefined is \f(CW\*(C`<ev.h>\*(C'\fR in \fIevent.h\fR and \f(CW"ev.h"\fR in \fIev.c\fR. This |
2509 | undefined is \f(CW\*(C`<ev.h>\*(C'\fR in \fIevent.h\fR and \f(CW"ev.h"\fR in \fIev.c\fR. This |
1739 | can be used to virtually rename the \fIev.h\fR header file in case of conflicts. |
2510 | can be used to virtually rename the \fIev.h\fR header file in case of conflicts. |
… | |
… | |
1757 | If undefined or defined to \f(CW1\fR, then all event-loop-specific functions |
2528 | If undefined or defined to \f(CW1\fR, then all event-loop-specific functions |
1758 | will have the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument, and you can create |
2529 | will have the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument, and you can create |
1759 | additional independent event loops. Otherwise there will be no support |
2530 | additional independent event loops. Otherwise there will be no support |
1760 | for multiple event loops and there is no first event loop pointer |
2531 | for multiple event loops and there is no first event loop pointer |
1761 | argument. Instead, all functions act on the single default loop. |
2532 | argument. Instead, all functions act on the single default loop. |
|
|
2533 | .IP "\s-1EV_MINPRI\s0" 4 |
|
|
2534 | .IX Item "EV_MINPRI" |
|
|
2535 | .PD 0 |
|
|
2536 | .IP "\s-1EV_MAXPRI\s0" 4 |
|
|
2537 | .IX Item "EV_MAXPRI" |
|
|
2538 | .PD |
|
|
2539 | The range of allowed priorities. \f(CW\*(C`EV_MINPRI\*(C'\fR must be smaller or equal to |
|
|
2540 | \&\f(CW\*(C`EV_MAXPRI\*(C'\fR, but otherwise there are no non-obvious limitations. You can |
|
|
2541 | provide for more priorities by overriding those symbols (usually defined |
|
|
2542 | to be \f(CW\*(C`\-2\*(C'\fR and \f(CW2\fR, respectively). |
|
|
2543 | .Sp |
|
|
2544 | When doing priority-based operations, libev usually has to linearly search |
|
|
2545 | all the priorities, so having many of them (hundreds) uses a lot of space |
|
|
2546 | and time, so using the defaults of five priorities (\-2 .. +2) is usually |
|
|
2547 | fine. |
|
|
2548 | .Sp |
|
|
2549 | If your embedding app does not need any priorities, defining these both to |
|
|
2550 | \&\f(CW0\fR will save some memory and cpu. |
1762 | .IP "\s-1EV_PERIODICS\s0" 4 |
2551 | .IP "\s-1EV_PERIODIC_ENABLE\s0" 4 |
1763 | .IX Item "EV_PERIODICS" |
2552 | .IX Item "EV_PERIODIC_ENABLE" |
1764 | If undefined or defined to be \f(CW1\fR, then periodic timers are supported, |
2553 | If undefined or defined to be \f(CW1\fR, then periodic timers are supported. If |
1765 | otherwise not. This saves a few kb of code. |
2554 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
|
|
2555 | code. |
|
|
2556 | .IP "\s-1EV_IDLE_ENABLE\s0" 4 |
|
|
2557 | .IX Item "EV_IDLE_ENABLE" |
|
|
2558 | If undefined or defined to be \f(CW1\fR, then idle watchers are supported. If |
|
|
2559 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
|
|
2560 | code. |
|
|
2561 | .IP "\s-1EV_EMBED_ENABLE\s0" 4 |
|
|
2562 | .IX Item "EV_EMBED_ENABLE" |
|
|
2563 | If undefined or defined to be \f(CW1\fR, then embed watchers are supported. If |
|
|
2564 | defined to be \f(CW0\fR, then they are not. |
|
|
2565 | .IP "\s-1EV_STAT_ENABLE\s0" 4 |
|
|
2566 | .IX Item "EV_STAT_ENABLE" |
|
|
2567 | If undefined or defined to be \f(CW1\fR, then stat watchers are supported. If |
|
|
2568 | defined to be \f(CW0\fR, then they are not. |
|
|
2569 | .IP "\s-1EV_FORK_ENABLE\s0" 4 |
|
|
2570 | .IX Item "EV_FORK_ENABLE" |
|
|
2571 | If undefined or defined to be \f(CW1\fR, then fork watchers are supported. If |
|
|
2572 | defined to be \f(CW0\fR, then they are not. |
|
|
2573 | .IP "\s-1EV_MINIMAL\s0" 4 |
|
|
2574 | .IX Item "EV_MINIMAL" |
|
|
2575 | If you need to shave off some kilobytes of code at the expense of some |
|
|
2576 | speed, define this symbol to \f(CW1\fR. Currently only used for gcc to override |
|
|
2577 | some inlining decisions, saves roughly 30% codesize of amd64. |
|
|
2578 | .IP "\s-1EV_PID_HASHSIZE\s0" 4 |
|
|
2579 | .IX Item "EV_PID_HASHSIZE" |
|
|
2580 | \&\f(CW\*(C`ev_child\*(C'\fR watchers use a small hash table to distribute workload by |
|
|
2581 | pid. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), usually more |
|
|
2582 | than enough. If you need to manage thousands of children you might want to |
|
|
2583 | increase this value (\fImust\fR be a power of two). |
|
|
2584 | .IP "\s-1EV_INOTIFY_HASHSIZE\s0" 4 |
|
|
2585 | .IX Item "EV_INOTIFY_HASHSIZE" |
|
|
2586 | \&\f(CW\*(C`ev_staz\*(C'\fR watchers use a small hash table to distribute workload by |
|
|
2587 | inotify watch id. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), |
|
|
2588 | usually more than enough. If you need to manage thousands of \f(CW\*(C`ev_stat\*(C'\fR |
|
|
2589 | watchers you might want to increase this value (\fImust\fR be a power of |
|
|
2590 | two). |
1766 | .IP "\s-1EV_COMMON\s0" 4 |
2591 | .IP "\s-1EV_COMMON\s0" 4 |
1767 | .IX Item "EV_COMMON" |
2592 | .IX Item "EV_COMMON" |
1768 | By default, all watchers have a \f(CW\*(C`void *data\*(C'\fR member. By redefining |
2593 | By default, all watchers have a \f(CW\*(C`void *data\*(C'\fR member. By redefining |
1769 | this macro to a something else you can include more and other types of |
2594 | this macro to a something else you can include more and other types of |
1770 | members. You have to define it each time you include one of the files, |
2595 | members. You have to define it each time you include one of the files, |
… | |
… | |
1775 | .Vb 3 |
2600 | .Vb 3 |
1776 | \& #define EV_COMMON \e |
2601 | \& #define EV_COMMON \e |
1777 | \& SV *self; /* contains this struct */ \e |
2602 | \& SV *self; /* contains this struct */ \e |
1778 | \& SV *cb_sv, *fh /* note no trailing ";" */ |
2603 | \& SV *cb_sv, *fh /* note no trailing ";" */ |
1779 | .Ve |
2604 | .Ve |
1780 | .IP "\s-1EV_CB_DECLARE\s0(type)" 4 |
2605 | .IP "\s-1EV_CB_DECLARE\s0 (type)" 4 |
1781 | .IX Item "EV_CB_DECLARE(type)" |
2606 | .IX Item "EV_CB_DECLARE (type)" |
1782 | .PD 0 |
2607 | .PD 0 |
1783 | .IP "\s-1EV_CB_INVOKE\s0(watcher,revents)" 4 |
2608 | .IP "\s-1EV_CB_INVOKE\s0 (watcher, revents)" 4 |
1784 | .IX Item "EV_CB_INVOKE(watcher,revents)" |
2609 | .IX Item "EV_CB_INVOKE (watcher, revents)" |
1785 | .IP "ev_set_cb(ev,cb)" 4 |
2610 | .IP "ev_set_cb (ev, cb)" 4 |
1786 | .IX Item "ev_set_cb(ev,cb)" |
2611 | .IX Item "ev_set_cb (ev, cb)" |
1787 | .PD |
2612 | .PD |
1788 | Can be used to change the callback member declaration in each watcher, |
2613 | Can be used to change the callback member declaration in each watcher, |
1789 | and the way callbacks are invoked and set. Must expand to a struct member |
2614 | and the way callbacks are invoked and set. Must expand to a struct member |
1790 | definition and a statement, respectively. See the \fIev.v\fR header file for |
2615 | definition and a statement, respectively. See the \fIev.v\fR header file for |
1791 | their default definitions. One possible use for overriding these is to |
2616 | their default definitions. One possible use for overriding these is to |
1792 | avoid the ev_loop pointer as first argument in all cases, or to use method |
2617 | avoid the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument in all cases, or to use |
1793 | calls instead of plain function calls in \*(C+. |
2618 | method calls instead of plain function calls in \*(C+. |
1794 | .Sh "\s-1EXAMPLES\s0" |
2619 | .Sh "\s-1EXAMPLES\s0" |
1795 | .IX Subsection "EXAMPLES" |
2620 | .IX Subsection "EXAMPLES" |
1796 | For a real-world example of a program the includes libev |
2621 | For a real-world example of a program the includes libev |
1797 | verbatim, you can have a look at the \s-1EV\s0 perl module |
2622 | verbatim, you can have a look at the \s-1EV\s0 perl module |
1798 | (<http://software.schmorp.de/pkg/EV.html>). It has the libev files in |
2623 | (<http://software.schmorp.de/pkg/EV.html>). It has the libev files in |
… | |
… | |
1800 | interface) and \fI\s-1EV\s0.xs\fR (implementation) files. Only the \fI\s-1EV\s0.xs\fR file |
2625 | interface) and \fI\s-1EV\s0.xs\fR (implementation) files. Only the \fI\s-1EV\s0.xs\fR file |
1801 | will be compiled. It is pretty complex because it provides its own header |
2626 | will be compiled. It is pretty complex because it provides its own header |
1802 | file. |
2627 | file. |
1803 | .Sp |
2628 | .Sp |
1804 | The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file |
2629 | The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file |
1805 | that everybody includes and which overrides some autoconf choices: |
2630 | that everybody includes and which overrides some configure choices: |
1806 | .Sp |
2631 | .Sp |
1807 | .Vb 4 |
2632 | .Vb 9 |
|
|
2633 | \& #define EV_MINIMAL 1 |
1808 | \& #define EV_USE_POLL 0 |
2634 | \& #define EV_USE_POLL 0 |
1809 | \& #define EV_MULTIPLICITY 0 |
2635 | \& #define EV_MULTIPLICITY 0 |
1810 | \& #define EV_PERIODICS 0 |
2636 | \& #define EV_PERIODIC_ENABLE 0 |
|
|
2637 | \& #define EV_STAT_ENABLE 0 |
|
|
2638 | \& #define EV_FORK_ENABLE 0 |
1811 | \& #define EV_CONFIG_H <config.h> |
2639 | \& #define EV_CONFIG_H <config.h> |
|
|
2640 | \& #define EV_MINPRI 0 |
|
|
2641 | \& #define EV_MAXPRI 0 |
1812 | .Ve |
2642 | .Ve |
1813 | .Sp |
2643 | .Sp |
1814 | .Vb 1 |
2644 | .Vb 1 |
1815 | \& #include "ev++.h" |
2645 | \& #include "ev++.h" |
1816 | .Ve |
2646 | .Ve |
… | |
… | |
1819 | .Sp |
2649 | .Sp |
1820 | .Vb 2 |
2650 | .Vb 2 |
1821 | \& #include "ev_cpp.h" |
2651 | \& #include "ev_cpp.h" |
1822 | \& #include "ev.c" |
2652 | \& #include "ev.c" |
1823 | .Ve |
2653 | .Ve |
|
|
2654 | .SH "COMPLEXITIES" |
|
|
2655 | .IX Header "COMPLEXITIES" |
|
|
2656 | In this section the complexities of (many of) the algorithms used inside |
|
|
2657 | libev will be explained. For complexity discussions about backends see the |
|
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2658 | documentation for \f(CW\*(C`ev_default_init\*(C'\fR. |
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2659 | .Sp |
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2660 | All of the following are about amortised time: If an array needs to be |
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2661 | extended, libev needs to realloc and move the whole array, but this |
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2662 | happens asymptotically never with higher number of elements, so O(1) might |
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2663 | mean it might do a lengthy realloc operation in rare cases, but on average |
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2664 | it is much faster and asymptotically approaches constant time. |
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2665 | .RS 4 |
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2666 | .IP "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" 4 |
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2667 | .IX Item "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" |
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2668 | This means that, when you have a watcher that triggers in one hour and |
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2669 | there are 100 watchers that would trigger before that then inserting will |
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2670 | have to skip those 100 watchers. |
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2671 | .IP "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" 4 |
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2672 | .IX Item "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" |
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2673 | That means that for changing a timer costs less than removing/adding them |
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2674 | as only the relative motion in the event queue has to be paid for. |
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2675 | .IP "Starting io/check/prepare/idle/signal/child watchers: O(1)" 4 |
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2676 | .IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)" |
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2677 | These just add the watcher into an array or at the head of a list. |
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2678 | =item Stopping check/prepare/idle watchers: O(1) |
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2679 | .IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % \s-1EV_PID_HASHSIZE\s0))" 4 |
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2680 | .IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))" |
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2681 | These watchers are stored in lists then need to be walked to find the |
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2682 | correct watcher to remove. The lists are usually short (you don't usually |
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2683 | have many watchers waiting for the same fd or signal). |
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2684 | .IP "Finding the next timer per loop iteration: O(1)" 4 |
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2685 | .IX Item "Finding the next timer per loop iteration: O(1)" |
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2686 | .PD 0 |
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2687 | .IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4 |
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2688 | .IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" |
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2689 | .PD |
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2690 | A change means an I/O watcher gets started or stopped, which requires |
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2691 | libev to recalculate its status (and possibly tell the kernel). |
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2692 | .IP "Activating one watcher: O(1)" 4 |
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2693 | .IX Item "Activating one watcher: O(1)" |
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2694 | .PD 0 |
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2695 | .IP "Priority handling: O(number_of_priorities)" 4 |
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2696 | .IX Item "Priority handling: O(number_of_priorities)" |
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2697 | .PD |
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2698 | Priorities are implemented by allocating some space for each |
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2699 | priority. When doing priority-based operations, libev usually has to |
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2700 | linearly search all the priorities. |
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2701 | .RE |
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2702 | .RS 4 |
1824 | .SH "AUTHOR" |
2703 | .SH "AUTHOR" |
1825 | .IX Header "AUTHOR" |
2704 | .IX Header "AUTHOR" |
1826 | Marc Lehmann <libev@schmorp.de>. |
2705 | Marc Lehmann <libev@schmorp.de>. |