… | |
… | |
126 | . ds Ae AE |
126 | . ds Ae AE |
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 "EV 1" |
132 | .TH "<STANDARD INPUT>" 1 "2007-11-27" "perl v5.8.8" "User Contributed Perl Documentation" |
132 | .TH EV 1 "2007-12-19" "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 |
177 | called \f(CW\*(C`ev_tstamp\*(C'\fR, which is what you should use too. It usually aliases |
246 | called \f(CW\*(C`ev_tstamp\*(C'\fR, which is what you should use too. It usually aliases |
178 | to the \f(CW\*(C`double\*(C'\fR type in C, and when you need to do any calculations on |
247 | to the \f(CW\*(C`double\*(C'\fR type in C, and when you need to do any calculations on |
179 | it, you should treat it as such. |
248 | it, you should treat it as some floatingpoint value. Unlike the name |
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249 | component \f(CW\*(C`stamp\*(C'\fR might indicate, it is also used for time differences |
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250 | throughout libev. |
180 | .SH "GLOBAL FUNCTIONS" |
251 | .SH "GLOBAL FUNCTIONS" |
181 | .IX Header "GLOBAL FUNCTIONS" |
252 | .IX Header "GLOBAL FUNCTIONS" |
182 | These functions can be called anytime, even before initialising the |
253 | These functions can be called anytime, even before initialising the |
183 | library in any way. |
254 | library in any way. |
184 | .IP "ev_tstamp ev_time ()" 4 |
255 | .IP "ev_tstamp ev_time ()" 4 |
… | |
… | |
190 | .IX Item "int ev_version_major ()" |
261 | .IX Item "int ev_version_major ()" |
191 | .PD 0 |
262 | .PD 0 |
192 | .IP "int ev_version_minor ()" 4 |
263 | .IP "int ev_version_minor ()" 4 |
193 | .IX Item "int ev_version_minor ()" |
264 | .IX Item "int ev_version_minor ()" |
194 | .PD |
265 | .PD |
195 | You can find out the major and minor version numbers of the library |
266 | 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 |
267 | 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 |
268 | \&\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 |
269 | 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. |
270 | version of the library your program was compiled against. |
200 | .Sp |
271 | .Sp |
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272 | These version numbers refer to the \s-1ABI\s0 version of the library, not the |
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273 | release version. |
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274 | .Sp |
201 | Usually, it's a good idea to terminate if the major versions mismatch, |
275 | Usually, it's a good idea to terminate if the major versions mismatch, |
202 | as this indicates an incompatible change. Minor versions are usually |
276 | as this indicates an incompatible change. Minor versions are usually |
203 | compatible to older versions, so a larger minor version alone is usually |
277 | compatible to older versions, so a larger minor version alone is usually |
204 | not a problem. |
278 | not a problem. |
205 | .Sp |
279 | .Sp |
206 | Example: make sure we haven't accidentally been linked against the wrong |
280 | Example: Make sure we haven't accidentally been linked against the wrong |
207 | version: |
281 | version. |
208 | .Sp |
282 | .Sp |
209 | .Vb 3 |
283 | .Vb 3 |
210 | \& assert (("libev version mismatch", |
284 | \& assert (("libev version mismatch", |
211 | \& ev_version_major () == EV_VERSION_MAJOR |
285 | \& ev_version_major () == EV_VERSION_MAJOR |
212 | \& && ev_version_minor () >= EV_VERSION_MINOR)); |
286 | \& && ev_version_minor () >= EV_VERSION_MINOR)); |
… | |
… | |
242 | recommended ones. |
316 | recommended ones. |
243 | .Sp |
317 | .Sp |
244 | See the description of \f(CW\*(C`ev_embed\*(C'\fR watchers for more info. |
318 | 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 |
319 | .IP "ev_set_allocator (void *(*cb)(void *ptr, long size))" 4 |
246 | .IX Item "ev_set_allocator (void *(*cb)(void *ptr, long size))" |
320 | .IX Item "ev_set_allocator (void *(*cb)(void *ptr, long size))" |
247 | Sets the allocation function to use (the prototype is similar to the |
321 | Sets the allocation function to use (the prototype is similar \- the |
248 | realloc C function, the semantics are identical). It is used to allocate |
322 | 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 |
323 | 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 |
324 | memory needs to be allocated, the library might abort or take some |
251 | destructive action. The default is your system realloc function. |
325 | potentially destructive action. The default is your system realloc |
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326 | function. |
252 | .Sp |
327 | .Sp |
253 | You could override this function in high-availability programs to, say, |
328 | 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, |
329 | 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. |
330 | or even to sleep a while and retry until some memory is available. |
256 | .Sp |
331 | .Sp |
257 | Example: replace the libev allocator with one that waits a bit and then |
332 | Example: Replace the libev allocator with one that waits a bit and then |
258 | retries: better than mine). |
333 | retries). |
259 | .Sp |
334 | .Sp |
260 | .Vb 6 |
335 | .Vb 6 |
261 | \& static void * |
336 | \& static void * |
262 | \& persistent_realloc (void *ptr, long size) |
337 | \& persistent_realloc (void *ptr, size_t size) |
263 | \& { |
338 | \& { |
264 | \& for (;;) |
339 | \& for (;;) |
265 | \& { |
340 | \& { |
266 | \& void *newptr = realloc (ptr, size); |
341 | \& void *newptr = realloc (ptr, size); |
267 | .Ve |
342 | .Ve |
… | |
… | |
289 | callback is set, then libev will expect it to remedy the sitution, no |
364 | 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 |
365 | 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 |
366 | requested operation, or, if the condition doesn't go away, do bad stuff |
292 | (such as abort). |
367 | (such as abort). |
293 | .Sp |
368 | .Sp |
294 | Example: do the same thing as libev does internally: |
369 | Example: This is basically the same thing that libev does internally, too. |
295 | .Sp |
370 | .Sp |
296 | .Vb 6 |
371 | .Vb 6 |
297 | \& static void |
372 | \& static void |
298 | \& fatal_error (const char *msg) |
373 | \& fatal_error (const char *msg) |
299 | \& { |
374 | \& { |
… | |
… | |
345 | or setgid) then libev will \fInot\fR look at the environment variable |
420 | 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 |
421 | \&\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 |
422 | 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 |
423 | useful to try out specific backends to test their performance, or to work |
349 | around bugs. |
424 | around bugs. |
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425 | .ie n .IP """EVFLAG_FORKCHECK""" 4 |
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426 | .el .IP "\f(CWEVFLAG_FORKCHECK\fR" 4 |
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427 | .IX Item "EVFLAG_FORKCHECK" |
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428 | 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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429 | a fork, you can also make libev check for a fork in each iteration by |
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430 | enabling this flag. |
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431 | .Sp |
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432 | This works by calling \f(CW\*(C`getpid ()\*(C'\fR on every iteration of the loop, |
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433 | and thus this might slow down your event loop if you do a lot of loop |
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434 | iterations and little real work, but is usually not noticeable (on my |
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435 | Linux system for example, \f(CW\*(C`getpid\*(C'\fR is actually a simple 5\-insn sequence |
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436 | without a syscall and thus \fIvery\fR fast, but my Linux system also has |
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437 | \&\f(CW\*(C`pthread_atfork\*(C'\fR which is even faster). |
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438 | .Sp |
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439 | The big advantage of this flag is that you can forget about fork (and |
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440 | forget about forgetting to tell libev about forking) when you use this |
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441 | flag. |
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442 | .Sp |
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443 | This flag setting cannot be overriden or specified in the \f(CW\*(C`LIBEV_FLAGS\*(C'\fR |
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444 | environment variable. |
350 | .ie n .IP """EVBACKEND_SELECT"" (value 1, portable select backend)" 4 |
445 | .ie n .IP """EVBACKEND_SELECT"" (value 1, portable select backend)" 4 |
351 | .el .IP "\f(CWEVBACKEND_SELECT\fR (value 1, portable select backend)" 4 |
446 | .el .IP "\f(CWEVBACKEND_SELECT\fR (value 1, portable select backend)" 4 |
352 | .IX Item "EVBACKEND_SELECT (value 1, portable select backend)" |
447 | .IX Item "EVBACKEND_SELECT (value 1, portable select backend)" |
353 | This is your standard \fIselect\fR\|(2) backend. Not \fIcompletely\fR standard, as |
448 | 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, |
449 | 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 |
543 | 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 |
544 | 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 |
545 | 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). |
546 | undefined behaviour (or a failed assertion if assertions are enabled). |
452 | .Sp |
547 | .Sp |
453 | Example: try to create a event loop that uses epoll and nothing else. |
548 | Example: Try to create a event loop that uses epoll and nothing else. |
454 | .Sp |
549 | .Sp |
455 | .Vb 3 |
550 | .Vb 3 |
456 | \& struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
551 | \& struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
457 | \& if (!epoller) |
552 | \& if (!epoller) |
458 | \& fatal ("no epoll found here, maybe it hides under your chair"); |
553 | \& fatal ("no epoll found here, maybe it hides under your chair"); |
… | |
… | |
462 | Destroys the default loop again (frees all memory and kernel state |
557 | Destroys the default loop again (frees all memory and kernel state |
463 | etc.). None of the active event watchers will be stopped in the normal |
558 | etc.). None of the active event watchers will be stopped in the normal |
464 | sense, so e.g. \f(CW\*(C`ev_is_active\*(C'\fR might still return true. It is your |
559 | sense, so e.g. \f(CW\*(C`ev_is_active\*(C'\fR might still return true. It is your |
465 | responsibility to either stop all watchers cleanly yoursef \fIbefore\fR |
560 | responsibility to either stop all watchers cleanly yoursef \fIbefore\fR |
466 | calling this function, or cope with the fact afterwards (which is usually |
561 | calling this function, or cope with the fact afterwards (which is usually |
467 | the easiest thing, youc na just ignore the watchers and/or \f(CW\*(C`free ()\*(C'\fR them |
562 | the easiest thing, you can just ignore the watchers and/or \f(CW\*(C`free ()\*(C'\fR them |
468 | for example). |
563 | for example). |
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564 | .Sp |
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565 | Not that certain global state, such as signal state, will not be freed by |
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566 | this function, and related watchers (such as signal and child watchers) |
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567 | would need to be stopped manually. |
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568 | .Sp |
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569 | In general it is not advisable to call this function except in the |
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570 | rare occasion where you really need to free e.g. the signal handling |
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571 | pipe fds. If you need dynamically allocated loops it is better to use |
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572 | \&\f(CW\*(C`ev_loop_new\*(C'\fR and \f(CW\*(C`ev_loop_destroy\*(C'\fR). |
469 | .IP "ev_loop_destroy (loop)" 4 |
573 | .IP "ev_loop_destroy (loop)" 4 |
470 | .IX Item "ev_loop_destroy (loop)" |
574 | .IX Item "ev_loop_destroy (loop)" |
471 | Like \f(CW\*(C`ev_default_destroy\*(C'\fR, but destroys an event loop created by an |
575 | Like \f(CW\*(C`ev_default_destroy\*(C'\fR, but destroys an event loop created by an |
472 | earlier call to \f(CW\*(C`ev_loop_new\*(C'\fR. |
576 | earlier call to \f(CW\*(C`ev_loop_new\*(C'\fR. |
473 | .IP "ev_default_fork ()" 4 |
577 | .IP "ev_default_fork ()" 4 |
… | |
… | |
495 | .IP "ev_loop_fork (loop)" 4 |
599 | .IP "ev_loop_fork (loop)" 4 |
496 | .IX Item "ev_loop_fork (loop)" |
600 | .IX Item "ev_loop_fork (loop)" |
497 | Like \f(CW\*(C`ev_default_fork\*(C'\fR, but acts on an event loop created by |
601 | 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 |
602 | \&\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. |
603 | after fork, and how you do this is entirely your own problem. |
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604 | .IP "unsigned int ev_loop_count (loop)" 4 |
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605 | .IX Item "unsigned int ev_loop_count (loop)" |
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606 | Returns the count of loop iterations for the loop, which is identical to |
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607 | the number of times libev did poll for new events. It starts at \f(CW0\fR and |
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608 | happily wraps around with enough iterations. |
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609 | .Sp |
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610 | This value can sometimes be useful as a generation counter of sorts (it |
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611 | \&\*(L"ticks\*(R" the number of loop iterations), as it roughly corresponds with |
|
|
612 | \&\f(CW\*(C`ev_prepare\*(C'\fR and \f(CW\*(C`ev_check\*(C'\fR calls. |
500 | .IP "unsigned int ev_backend (loop)" 4 |
613 | .IP "unsigned int ev_backend (loop)" 4 |
501 | .IX Item "unsigned int ev_backend (loop)" |
614 | .IX Item "unsigned int ev_backend (loop)" |
502 | Returns one of the \f(CW\*(C`EVBACKEND_*\*(C'\fR flags indicating the event backend in |
615 | Returns one of the \f(CW\*(C`EVBACKEND_*\*(C'\fR flags indicating the event backend in |
503 | use. |
616 | use. |
504 | .IP "ev_tstamp ev_now (loop)" 4 |
617 | .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 |
648 | 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. |
649 | usually a better approach for this kind of thing. |
537 | .Sp |
650 | .Sp |
538 | Here are the gory details of what \f(CW\*(C`ev_loop\*(C'\fR does: |
651 | Here are the gory details of what \f(CW\*(C`ev_loop\*(C'\fR does: |
539 | .Sp |
652 | .Sp |
540 | .Vb 18 |
653 | .Vb 19 |
|
|
654 | \& - Before the first iteration, call any pending watchers. |
541 | \& * If there are no active watchers (reference count is zero), return. |
655 | \& * If there are no active watchers (reference count is zero), return. |
542 | \& - Queue prepare watchers and then call all outstanding watchers. |
656 | \& - Queue all prepare watchers and then call all outstanding watchers. |
543 | \& - If we have been forked, recreate the kernel state. |
657 | \& - If we have been forked, recreate the kernel state. |
544 | \& - Update the kernel state with all outstanding changes. |
658 | \& - Update the kernel state with all outstanding changes. |
545 | \& - Update the "event loop time". |
659 | \& - Update the "event loop time". |
546 | \& - Calculate for how long to block. |
660 | \& - Calculate for how long to block. |
547 | \& - Block the process, waiting for any events. |
661 | \& - Block the process, waiting for any events. |
… | |
… | |
556 | \& be handled here by queueing them when their watcher gets executed. |
670 | \& be handled here by queueing them when their watcher gets executed. |
557 | \& - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
671 | \& - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
558 | \& were used, return, otherwise continue with step *. |
672 | \& were used, return, otherwise continue with step *. |
559 | .Ve |
673 | .Ve |
560 | .Sp |
674 | .Sp |
561 | Example: queue some jobs and then loop until no events are outsanding |
675 | Example: Queue some jobs and then loop until no events are outsanding |
562 | anymore. |
676 | anymore. |
563 | .Sp |
677 | .Sp |
564 | .Vb 4 |
678 | .Vb 4 |
565 | \& ... queue jobs here, make sure they register event watchers as long |
679 | \& ... 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..) |
680 | \& ... 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 |
702 | 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 |
703 | 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 |
704 | 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. |
705 | libraries. Just remember to \fIunref after start\fR and \fIref before stop\fR. |
592 | .Sp |
706 | .Sp |
593 | Example: create a signal watcher, but keep it from keeping \f(CW\*(C`ev_loop\*(C'\fR |
707 | Example: Create a signal watcher, but keep it from keeping \f(CW\*(C`ev_loop\*(C'\fR |
594 | running when nothing else is active. |
708 | running when nothing else is active. |
595 | .Sp |
709 | .Sp |
596 | .Vb 4 |
710 | .Vb 4 |
597 | \& struct dv_signal exitsig; |
711 | \& struct ev_signal exitsig; |
598 | \& ev_signal_init (&exitsig, sig_cb, SIGINT); |
712 | \& ev_signal_init (&exitsig, sig_cb, SIGINT); |
599 | \& ev_signal_start (myloop, &exitsig); |
713 | \& ev_signal_start (loop, &exitsig); |
600 | \& evf_unref (myloop); |
714 | \& evf_unref (loop); |
601 | .Ve |
715 | .Ve |
602 | .Sp |
716 | .Sp |
603 | Example: for some weird reason, unregister the above signal handler again. |
717 | Example: For some weird reason, unregister the above signal handler again. |
604 | .Sp |
718 | .Sp |
605 | .Vb 2 |
719 | .Vb 2 |
606 | \& ev_ref (myloop); |
720 | \& ev_ref (loop); |
607 | \& ev_signal_stop (myloop, &exitsig); |
721 | \& ev_signal_stop (loop, &exitsig); |
608 | .Ve |
722 | .Ve |
609 | .SH "ANATOMY OF A WATCHER" |
723 | .SH "ANATOMY OF A WATCHER" |
610 | .IX Header "ANATOMY OF A WATCHER" |
724 | .IX Header "ANATOMY OF A WATCHER" |
611 | A watcher is a structure that you create and register to record your |
725 | 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 |
726 | interest in some event. For instance, if you want to wait for \s-1STDIN\s0 to |
… | |
… | |
707 | \&\f(CW\*(C`ev_loop\*(C'\fR has gathered them, but before it invokes any callbacks for any |
821 | \&\f(CW\*(C`ev_loop\*(C'\fR has gathered them, but before it invokes any callbacks for any |
708 | received events. Callbacks of both watcher types can start and stop as |
822 | received events. Callbacks of both watcher types can start and stop as |
709 | many watchers as they want, and all of them will be taken into account |
823 | many watchers as they want, and all of them will be taken into account |
710 | (for example, a \f(CW\*(C`ev_prepare\*(C'\fR watcher might start an idle watcher to keep |
824 | (for example, a \f(CW\*(C`ev_prepare\*(C'\fR watcher might start an idle watcher to keep |
711 | \&\f(CW\*(C`ev_loop\*(C'\fR from blocking). |
825 | \&\f(CW\*(C`ev_loop\*(C'\fR from blocking). |
|
|
826 | .ie n .IP """EV_EMBED""" 4 |
|
|
827 | .el .IP "\f(CWEV_EMBED\fR" 4 |
|
|
828 | .IX Item "EV_EMBED" |
|
|
829 | The embedded event loop specified in the \f(CW\*(C`ev_embed\*(C'\fR watcher needs attention. |
|
|
830 | .ie n .IP """EV_FORK""" 4 |
|
|
831 | .el .IP "\f(CWEV_FORK\fR" 4 |
|
|
832 | .IX Item "EV_FORK" |
|
|
833 | The event loop has been resumed in the child process after fork (see |
|
|
834 | \&\f(CW\*(C`ev_fork\*(C'\fR). |
712 | .ie n .IP """EV_ERROR""" 4 |
835 | .ie n .IP """EV_ERROR""" 4 |
713 | .el .IP "\f(CWEV_ERROR\fR" 4 |
836 | .el .IP "\f(CWEV_ERROR\fR" 4 |
714 | .IX Item "EV_ERROR" |
837 | .IX Item "EV_ERROR" |
715 | An unspecified error has occured, the watcher has been stopped. This might |
838 | An unspecified error has occured, the watcher has been stopped. This might |
716 | happen because the watcher could not be properly started because libev |
839 | happen because the watcher could not be properly started because libev |
… | |
… | |
781 | .IP "bool ev_is_pending (ev_TYPE *watcher)" 4 |
904 | .IP "bool ev_is_pending (ev_TYPE *watcher)" 4 |
782 | .IX Item "bool ev_is_pending (ev_TYPE *watcher)" |
905 | .IX Item "bool ev_is_pending (ev_TYPE *watcher)" |
783 | Returns a true value iff the watcher is pending, (i.e. it has outstanding |
906 | Returns a true value iff the watcher is pending, (i.e. it has outstanding |
784 | events but its callback has not yet been invoked). As long as a watcher |
907 | events but its callback has not yet been invoked). As long as a watcher |
785 | is pending (but not active) you must not call an init function on it (but |
908 | is pending (but not active) you must not call an init function on it (but |
786 | \&\f(CW\*(C`ev_TYPE_set\*(C'\fR is safe) and you must make sure the watcher is available to |
909 | \&\f(CW\*(C`ev_TYPE_set\*(C'\fR is safe), you must not change its priority, and you must |
787 | libev (e.g. you cnanot \f(CW\*(C`free ()\*(C'\fR it). |
910 | make sure the watcher is available to libev (e.g. you cannot \f(CW\*(C`free ()\*(C'\fR |
|
|
911 | it). |
788 | .IP "callback = ev_cb (ev_TYPE *watcher)" 4 |
912 | .IP "callback ev_cb (ev_TYPE *watcher)" 4 |
789 | .IX Item "callback = ev_cb (ev_TYPE *watcher)" |
913 | .IX Item "callback ev_cb (ev_TYPE *watcher)" |
790 | Returns the callback currently set on the watcher. |
914 | Returns the callback currently set on the watcher. |
791 | .IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 |
915 | .IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 |
792 | .IX Item "ev_cb_set (ev_TYPE *watcher, callback)" |
916 | .IX Item "ev_cb_set (ev_TYPE *watcher, callback)" |
793 | Change the callback. You can change the callback at virtually any time |
917 | Change the callback. You can change the callback at virtually any time |
794 | (modulo threads). |
918 | (modulo threads). |
|
|
919 | .IP "ev_set_priority (ev_TYPE *watcher, priority)" 4 |
|
|
920 | .IX Item "ev_set_priority (ev_TYPE *watcher, priority)" |
|
|
921 | .PD 0 |
|
|
922 | .IP "int ev_priority (ev_TYPE *watcher)" 4 |
|
|
923 | .IX Item "int ev_priority (ev_TYPE *watcher)" |
|
|
924 | .PD |
|
|
925 | Set and query the priority of the watcher. The priority is a small |
|
|
926 | integer between \f(CW\*(C`EV_MAXPRI\*(C'\fR (default: \f(CW2\fR) and \f(CW\*(C`EV_MINPRI\*(C'\fR |
|
|
927 | (default: \f(CW\*(C`\-2\*(C'\fR). Pending watchers with higher priority will be invoked |
|
|
928 | before watchers with lower priority, but priority will not keep watchers |
|
|
929 | from being executed (except for \f(CW\*(C`ev_idle\*(C'\fR watchers). |
|
|
930 | .Sp |
|
|
931 | This means that priorities are \fIonly\fR used for ordering callback |
|
|
932 | invocation after new events have been received. This is useful, for |
|
|
933 | example, to reduce latency after idling, or more often, to bind two |
|
|
934 | watchers on the same event and make sure one is called first. |
|
|
935 | .Sp |
|
|
936 | If you need to suppress invocation when higher priority events are pending |
|
|
937 | you need to look at \f(CW\*(C`ev_idle\*(C'\fR watchers, which provide this functionality. |
|
|
938 | .Sp |
|
|
939 | You \fImust not\fR change the priority of a watcher as long as it is active or |
|
|
940 | pending. |
|
|
941 | .Sp |
|
|
942 | The default priority used by watchers when no priority has been set is |
|
|
943 | always \f(CW0\fR, which is supposed to not be too high and not be too low :). |
|
|
944 | .Sp |
|
|
945 | Setting a priority outside the range of \f(CW\*(C`EV_MINPRI\*(C'\fR to \f(CW\*(C`EV_MAXPRI\*(C'\fR is |
|
|
946 | fine, as long as you do not mind that the priority value you query might |
|
|
947 | or might not have been adjusted to be within valid range. |
|
|
948 | .IP "ev_invoke (loop, ev_TYPE *watcher, int revents)" 4 |
|
|
949 | .IX Item "ev_invoke (loop, ev_TYPE *watcher, int revents)" |
|
|
950 | 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 |
|
|
951 | \&\f(CW\*(C`loop\*(C'\fR nor \f(CW\*(C`revents\*(C'\fR need to be valid as long as the watcher callback |
|
|
952 | can deal with that fact. |
|
|
953 | .IP "int ev_clear_pending (loop, ev_TYPE *watcher)" 4 |
|
|
954 | .IX Item "int ev_clear_pending (loop, ev_TYPE *watcher)" |
|
|
955 | If the watcher is pending, this function returns clears its pending status |
|
|
956 | and returns its \f(CW\*(C`revents\*(C'\fR bitset (as if its callback was invoked). If the |
|
|
957 | watcher isn't pending it does nothing and returns \f(CW0\fR. |
795 | .Sh "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0" |
958 | .Sh "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0" |
796 | .IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER" |
959 | .IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER" |
797 | Each watcher has, by default, a member \f(CW\*(C`void *data\*(C'\fR that you can change |
960 | Each watcher has, by default, a member \f(CW\*(C`void *data\*(C'\fR that you can change |
798 | and read at any time, libev will completely ignore it. This can be used |
961 | and read at any time, libev will completely ignore it. This can be used |
799 | to associate arbitrary data with your watcher. If you need more data and |
962 | to associate arbitrary data with your watcher. If you need more data and |
… | |
… | |
820 | \& struct my_io *w = (struct my_io *)w_; |
983 | \& struct my_io *w = (struct my_io *)w_; |
821 | \& ... |
984 | \& ... |
822 | \& } |
985 | \& } |
823 | .Ve |
986 | .Ve |
824 | .PP |
987 | .PP |
825 | More interesting and less C\-conformant ways of catsing your callback type |
988 | More interesting and less C\-conformant ways of casting your callback type |
826 | have been omitted.... |
989 | instead have been omitted. |
|
|
990 | .PP |
|
|
991 | Another common scenario is having some data structure with multiple |
|
|
992 | watchers: |
|
|
993 | .PP |
|
|
994 | .Vb 6 |
|
|
995 | \& struct my_biggy |
|
|
996 | \& { |
|
|
997 | \& int some_data; |
|
|
998 | \& ev_timer t1; |
|
|
999 | \& ev_timer t2; |
|
|
1000 | \& } |
|
|
1001 | .Ve |
|
|
1002 | .PP |
|
|
1003 | In this case getting the pointer to \f(CW\*(C`my_biggy\*(C'\fR is a bit more complicated, |
|
|
1004 | you need to use \f(CW\*(C`offsetof\*(C'\fR: |
|
|
1005 | .PP |
|
|
1006 | .Vb 1 |
|
|
1007 | \& #include <stddef.h> |
|
|
1008 | .Ve |
|
|
1009 | .PP |
|
|
1010 | .Vb 6 |
|
|
1011 | \& static void |
|
|
1012 | \& t1_cb (EV_P_ struct ev_timer *w, int revents) |
|
|
1013 | \& { |
|
|
1014 | \& struct my_biggy big = (struct my_biggy * |
|
|
1015 | \& (((char *)w) - offsetof (struct my_biggy, t1)); |
|
|
1016 | \& } |
|
|
1017 | .Ve |
|
|
1018 | .PP |
|
|
1019 | .Vb 6 |
|
|
1020 | \& static void |
|
|
1021 | \& t2_cb (EV_P_ struct ev_timer *w, int revents) |
|
|
1022 | \& { |
|
|
1023 | \& struct my_biggy big = (struct my_biggy * |
|
|
1024 | \& (((char *)w) - offsetof (struct my_biggy, t2)); |
|
|
1025 | \& } |
|
|
1026 | .Ve |
827 | .SH "WATCHER TYPES" |
1027 | .SH "WATCHER TYPES" |
828 | .IX Header "WATCHER TYPES" |
1028 | .IX Header "WATCHER TYPES" |
829 | This section describes each watcher in detail, but will not repeat |
1029 | This section describes each watcher in detail, but will not repeat |
830 | information given in the last section. Any initialisation/set macros, |
1030 | information given in the last section. Any initialisation/set macros, |
831 | functions and members specific to the watcher type are explained. |
1031 | functions and members specific to the watcher type are explained. |
… | |
… | |
873 | it is best to always use non-blocking I/O: An extra \f(CW\*(C`read\*(C'\fR(2) returning |
1073 | it is best to always use non-blocking I/O: An extra \f(CW\*(C`read\*(C'\fR(2) returning |
874 | \&\f(CW\*(C`EAGAIN\*(C'\fR is far preferable to a program hanging until some data arrives. |
1074 | \&\f(CW\*(C`EAGAIN\*(C'\fR is far preferable to a program hanging until some data arrives. |
875 | .PP |
1075 | .PP |
876 | If you cannot run the fd in non-blocking mode (for example you should not |
1076 | If you cannot run the fd in non-blocking mode (for example you should not |
877 | play around with an Xlib connection), then you have to seperately re-test |
1077 | play around with an Xlib connection), then you have to seperately re-test |
878 | wether a file descriptor is really ready with a known-to-be good interface |
1078 | whether a file descriptor is really ready with a known-to-be good interface |
879 | such as poll (fortunately in our Xlib example, Xlib already does this on |
1079 | such as poll (fortunately in our Xlib example, Xlib already does this on |
880 | its own, so its quite safe to use). |
1080 | its own, so its quite safe to use). |
|
|
1081 | .PP |
|
|
1082 | \fIThe special problem of disappearing file descriptors\fR |
|
|
1083 | .IX Subsection "The special problem of disappearing file descriptors" |
|
|
1084 | .PP |
|
|
1085 | Some backends (e.g kqueue, epoll) need to be told about closing a file |
|
|
1086 | descriptor (either by calling \f(CW\*(C`close\*(C'\fR explicitly or by any other means, |
|
|
1087 | such as \f(CW\*(C`dup\*(C'\fR). The reason is that you register interest in some file |
|
|
1088 | descriptor, but when it goes away, the operating system will silently drop |
|
|
1089 | this interest. If another file descriptor with the same number then is |
|
|
1090 | registered with libev, there is no efficient way to see that this is, in |
|
|
1091 | fact, a different file descriptor. |
|
|
1092 | .PP |
|
|
1093 | To avoid having to explicitly tell libev about such cases, libev follows |
|
|
1094 | the following policy: Each time \f(CW\*(C`ev_io_set\*(C'\fR is being called, libev |
|
|
1095 | will assume that this is potentially a new file descriptor, otherwise |
|
|
1096 | it is assumed that the file descriptor stays the same. That means that |
|
|
1097 | 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 |
|
|
1098 | descriptor even if the file descriptor number itself did not change. |
|
|
1099 | .PP |
|
|
1100 | This is how one would do it normally anyway, the important point is that |
|
|
1101 | the libev application should not optimise around libev but should leave |
|
|
1102 | optimisations to libev. |
|
|
1103 | .PP |
|
|
1104 | \fIWatcher-Specific Functions\fR |
|
|
1105 | .IX Subsection "Watcher-Specific Functions" |
881 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
1106 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
882 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
1107 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
883 | .PD 0 |
1108 | .PD 0 |
884 | .IP "ev_io_set (ev_io *, int fd, int events)" 4 |
1109 | .IP "ev_io_set (ev_io *, int fd, int events)" 4 |
885 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
1110 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
… | |
… | |
892 | The file descriptor being watched. |
1117 | The file descriptor being watched. |
893 | .IP "int events [read\-only]" 4 |
1118 | .IP "int events [read\-only]" 4 |
894 | .IX Item "int events [read-only]" |
1119 | .IX Item "int events [read-only]" |
895 | The events being watched. |
1120 | The events being watched. |
896 | .PP |
1121 | .PP |
897 | Example: call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well |
1122 | Example: Call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well |
898 | readable, but only once. Since it is likely line\-buffered, you could |
1123 | readable, but only once. Since it is likely line\-buffered, you could |
899 | attempt to read a whole line in the callback: |
1124 | attempt to read a whole line in the callback. |
900 | .PP |
1125 | .PP |
901 | .Vb 6 |
1126 | .Vb 6 |
902 | \& static void |
1127 | \& static void |
903 | \& stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
1128 | \& stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
904 | \& { |
1129 | \& { |
… | |
… | |
938 | .Ve |
1163 | .Ve |
939 | .PP |
1164 | .PP |
940 | The callback is guarenteed to be invoked only when its timeout has passed, |
1165 | The callback is guarenteed to be invoked only when its timeout has passed, |
941 | but if multiple timers become ready during the same loop iteration then |
1166 | but if multiple timers become ready during the same loop iteration then |
942 | order of execution is undefined. |
1167 | order of execution is undefined. |
|
|
1168 | .PP |
|
|
1169 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1170 | .IX Subsection "Watcher-Specific Functions and Data Members" |
943 | .IP "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" 4 |
1171 | .IP "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" 4 |
944 | .IX Item "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" |
1172 | .IX Item "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" |
945 | .PD 0 |
1173 | .PD 0 |
946 | .IP "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)" 4 |
1174 | .IP "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)" 4 |
947 | .IX Item "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)" |
1175 | .IX Item "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)" |
… | |
… | |
959 | .IP "ev_timer_again (loop)" 4 |
1187 | .IP "ev_timer_again (loop)" 4 |
960 | .IX Item "ev_timer_again (loop)" |
1188 | .IX Item "ev_timer_again (loop)" |
961 | This will act as if the timer timed out and restart it again if it is |
1189 | This will act as if the timer timed out and restart it again if it is |
962 | repeating. The exact semantics are: |
1190 | repeating. The exact semantics are: |
963 | .Sp |
1191 | .Sp |
|
|
1192 | If the timer is pending, its pending status is cleared. |
|
|
1193 | .Sp |
964 | If the timer is started but nonrepeating, stop it. |
1194 | If the timer is started but nonrepeating, stop it (as if it timed out). |
965 | .Sp |
1195 | .Sp |
966 | If the timer is repeating, either start it if necessary (with the repeat |
1196 | If the timer is repeating, either start it if necessary (with the |
967 | value), or reset the running timer to the repeat value. |
1197 | \&\f(CW\*(C`repeat\*(C'\fR value), or reset the running timer to the \f(CW\*(C`repeat\*(C'\fR value. |
968 | .Sp |
1198 | .Sp |
969 | This sounds a bit complicated, but here is a useful and typical |
1199 | This sounds a bit complicated, but here is a useful and typical |
970 | example: Imagine you have a tcp connection and you want a so-called |
1200 | example: Imagine you have a tcp connection and you want a so-called idle |
971 | idle timeout, that is, you want to be called when there have been, |
1201 | timeout, that is, you want to be called when there have been, say, 60 |
972 | say, 60 seconds of inactivity on the socket. The easiest way to do |
1202 | seconds of inactivity on the socket. The easiest way to do this is to |
973 | this is to configure an \f(CW\*(C`ev_timer\*(C'\fR with \f(CW\*(C`after\*(C'\fR=\f(CW\*(C`repeat\*(C'\fR=\f(CW60\fR and calling |
1203 | 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 |
974 | \&\f(CW\*(C`ev_timer_again\*(C'\fR each time you successfully read or write some data. If |
1204 | \&\f(CW\*(C`ev_timer_again\*(C'\fR each time you successfully read or write some data. If |
975 | you go into an idle state where you do not expect data to travel on the |
1205 | you go into an idle state where you do not expect data to travel on the |
976 | socket, you can stop the timer, and again will automatically restart it if |
1206 | socket, you can \f(CW\*(C`ev_timer_stop\*(C'\fR the timer, and \f(CW\*(C`ev_timer_again\*(C'\fR will |
977 | need be. |
1207 | automatically restart it if need be. |
978 | .Sp |
1208 | .Sp |
979 | You can also ignore the \f(CW\*(C`after\*(C'\fR value and \f(CW\*(C`ev_timer_start\*(C'\fR altogether |
1209 | That means you can ignore the \f(CW\*(C`after\*(C'\fR value and \f(CW\*(C`ev_timer_start\*(C'\fR |
980 | and only ever use the \f(CW\*(C`repeat\*(C'\fR value: |
1210 | altogether and only ever use the \f(CW\*(C`repeat\*(C'\fR value and \f(CW\*(C`ev_timer_again\*(C'\fR: |
981 | .Sp |
1211 | .Sp |
982 | .Vb 8 |
1212 | .Vb 8 |
983 | \& ev_timer_init (timer, callback, 0., 5.); |
1213 | \& ev_timer_init (timer, callback, 0., 5.); |
984 | \& ev_timer_again (loop, timer); |
1214 | \& ev_timer_again (loop, timer); |
985 | \& ... |
1215 | \& ... |
… | |
… | |
988 | \& ... |
1218 | \& ... |
989 | \& timer->again = 10.; |
1219 | \& timer->again = 10.; |
990 | \& ev_timer_again (loop, timer); |
1220 | \& ev_timer_again (loop, timer); |
991 | .Ve |
1221 | .Ve |
992 | .Sp |
1222 | .Sp |
993 | This is more efficient then stopping/starting the timer eahc time you want |
1223 | This is more slightly efficient then stopping/starting the timer each time |
994 | to modify its timeout value. |
1224 | you want to modify its timeout value. |
995 | .IP "ev_tstamp repeat [read\-write]" 4 |
1225 | .IP "ev_tstamp repeat [read\-write]" 4 |
996 | .IX Item "ev_tstamp repeat [read-write]" |
1226 | .IX Item "ev_tstamp repeat [read-write]" |
997 | The current \f(CW\*(C`repeat\*(C'\fR value. Will be used each time the watcher times out |
1227 | The current \f(CW\*(C`repeat\*(C'\fR value. Will be used each time the watcher times out |
998 | or \f(CW\*(C`ev_timer_again\*(C'\fR is called and determines the next timeout (if any), |
1228 | or \f(CW\*(C`ev_timer_again\*(C'\fR is called and determines the next timeout (if any), |
999 | which is also when any modifications are taken into account. |
1229 | which is also when any modifications are taken into account. |
1000 | .PP |
1230 | .PP |
1001 | Example: create a timer that fires after 60 seconds. |
1231 | Example: Create a timer that fires after 60 seconds. |
1002 | .PP |
1232 | .PP |
1003 | .Vb 5 |
1233 | .Vb 5 |
1004 | \& static void |
1234 | \& static void |
1005 | \& one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1235 | \& one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1006 | \& { |
1236 | \& { |
… | |
… | |
1012 | \& struct ev_timer mytimer; |
1242 | \& struct ev_timer mytimer; |
1013 | \& ev_timer_init (&mytimer, one_minute_cb, 60., 0.); |
1243 | \& ev_timer_init (&mytimer, one_minute_cb, 60., 0.); |
1014 | \& ev_timer_start (loop, &mytimer); |
1244 | \& ev_timer_start (loop, &mytimer); |
1015 | .Ve |
1245 | .Ve |
1016 | .PP |
1246 | .PP |
1017 | Example: create a timeout timer that times out after 10 seconds of |
1247 | Example: Create a timeout timer that times out after 10 seconds of |
1018 | inactivity. |
1248 | inactivity. |
1019 | .PP |
1249 | .PP |
1020 | .Vb 5 |
1250 | .Vb 5 |
1021 | \& static void |
1251 | \& static void |
1022 | \& timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1252 | \& timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
… | |
… | |
1047 | but on wallclock time (absolute time). You can tell a periodic watcher |
1277 | but on wallclock time (absolute time). You can tell a periodic watcher |
1048 | to trigger \*(L"at\*(R" some specific point in time. For example, if you tell a |
1278 | to trigger \*(L"at\*(R" some specific point in time. For example, if you tell a |
1049 | periodic watcher to trigger in 10 seconds (by specifiying e.g. \f(CW\*(C`ev_now () |
1279 | periodic watcher to trigger in 10 seconds (by specifiying e.g. \f(CW\*(C`ev_now () |
1050 | + 10.\*(C'\fR) and then reset your system clock to the last year, then it will |
1280 | + 10.\*(C'\fR) and then reset your system clock to the last year, then it will |
1051 | take a year to trigger the event (unlike an \f(CW\*(C`ev_timer\*(C'\fR, which would trigger |
1281 | take a year to trigger the event (unlike an \f(CW\*(C`ev_timer\*(C'\fR, which would trigger |
1052 | roughly 10 seconds later and of course not if you reset your system time |
1282 | roughly 10 seconds later). |
1053 | again). |
|
|
1054 | .PP |
1283 | .PP |
1055 | They can also be used to implement vastly more complex timers, such as |
1284 | They can also be used to implement vastly more complex timers, such as |
1056 | triggering an event on eahc midnight, local time. |
1285 | triggering an event on each midnight, local time or other, complicated, |
|
|
1286 | rules. |
1057 | .PP |
1287 | .PP |
1058 | As with timers, the callback is guarenteed to be invoked only when the |
1288 | As with timers, the callback is guarenteed to be invoked only when the |
1059 | time (\f(CW\*(C`at\*(C'\fR) has been passed, but if multiple periodic timers become ready |
1289 | time (\f(CW\*(C`at\*(C'\fR) has been passed, but if multiple periodic timers become ready |
1060 | during the same loop iteration then order of execution is undefined. |
1290 | during the same loop iteration then order of execution is undefined. |
|
|
1291 | .PP |
|
|
1292 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1293 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1061 | .IP "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" 4 |
1294 | .IP "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" 4 |
1062 | .IX Item "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" |
1295 | .IX Item "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" |
1063 | .PD 0 |
1296 | .PD 0 |
1064 | .IP "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" 4 |
1297 | .IP "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" 4 |
1065 | .IX Item "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" |
1298 | .IX Item "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" |
1066 | .PD |
1299 | .PD |
1067 | Lots of arguments, lets sort it out... There are basically three modes of |
1300 | Lots of arguments, lets sort it out... There are basically three modes of |
1068 | operation, and we will explain them from simplest to complex: |
1301 | operation, and we will explain them from simplest to complex: |
1069 | .RS 4 |
1302 | .RS 4 |
1070 | .IP "* absolute timer (interval = reschedule_cb = 0)" 4 |
1303 | .IP "* absolute timer (at = time, interval = reschedule_cb = 0)" 4 |
1071 | .IX Item "absolute timer (interval = reschedule_cb = 0)" |
1304 | .IX Item "absolute timer (at = time, interval = reschedule_cb = 0)" |
1072 | In this configuration the watcher triggers an event at the wallclock time |
1305 | In this configuration the watcher triggers an event at the wallclock time |
1073 | \&\f(CW\*(C`at\*(C'\fR and doesn't repeat. It will not adjust when a time jump occurs, |
1306 | \&\f(CW\*(C`at\*(C'\fR and doesn't repeat. It will not adjust when a time jump occurs, |
1074 | that is, if it is to be run at January 1st 2011 then it will run when the |
1307 | that is, if it is to be run at January 1st 2011 then it will run when the |
1075 | system time reaches or surpasses this time. |
1308 | system time reaches or surpasses this time. |
1076 | .IP "* non-repeating interval timer (interval > 0, reschedule_cb = 0)" 4 |
1309 | .IP "* non-repeating interval timer (at = offset, interval > 0, reschedule_cb = 0)" 4 |
1077 | .IX Item "non-repeating interval timer (interval > 0, reschedule_cb = 0)" |
1310 | .IX Item "non-repeating interval timer (at = offset, interval > 0, reschedule_cb = 0)" |
1078 | In this mode the watcher will always be scheduled to time out at the next |
1311 | In this mode the watcher will always be scheduled to time out at the next |
1079 | \&\f(CW\*(C`at + N * interval\*(C'\fR time (for some integer N) and then repeat, regardless |
1312 | \&\f(CW\*(C`at + N * interval\*(C'\fR time (for some integer N, which can also be negative) |
1080 | of any time jumps. |
1313 | and then repeat, regardless of any time jumps. |
1081 | .Sp |
1314 | .Sp |
1082 | This can be used to create timers that do not drift with respect to system |
1315 | This can be used to create timers that do not drift with respect to system |
1083 | time: |
1316 | time: |
1084 | .Sp |
1317 | .Sp |
1085 | .Vb 1 |
1318 | .Vb 1 |
… | |
… | |
1092 | by 3600. |
1325 | by 3600. |
1093 | .Sp |
1326 | .Sp |
1094 | Another way to think about it (for the mathematically inclined) is that |
1327 | Another way to think about it (for the mathematically inclined) is that |
1095 | \&\f(CW\*(C`ev_periodic\*(C'\fR will try to run the callback in this mode at the next possible |
1328 | \&\f(CW\*(C`ev_periodic\*(C'\fR will try to run the callback in this mode at the next possible |
1096 | time where \f(CW\*(C`time = at (mod interval)\*(C'\fR, regardless of any time jumps. |
1329 | time where \f(CW\*(C`time = at (mod interval)\*(C'\fR, regardless of any time jumps. |
|
|
1330 | .Sp |
|
|
1331 | For numerical stability it is preferable that the \f(CW\*(C`at\*(C'\fR value is near |
|
|
1332 | \&\f(CW\*(C`ev_now ()\*(C'\fR (the current time), but there is no range requirement for |
|
|
1333 | this value. |
1097 | .IP "* manual reschedule mode (reschedule_cb = callback)" 4 |
1334 | .IP "* manual reschedule mode (at and interval ignored, reschedule_cb = callback)" 4 |
1098 | .IX Item "manual reschedule mode (reschedule_cb = callback)" |
1335 | .IX Item "manual reschedule mode (at and interval ignored, reschedule_cb = callback)" |
1099 | In this mode the values for \f(CW\*(C`interval\*(C'\fR and \f(CW\*(C`at\*(C'\fR are both being |
1336 | In this mode the values for \f(CW\*(C`interval\*(C'\fR and \f(CW\*(C`at\*(C'\fR are both being |
1100 | ignored. Instead, each time the periodic watcher gets scheduled, the |
1337 | ignored. Instead, each time the periodic watcher gets scheduled, the |
1101 | reschedule callback will be called with the watcher as first, and the |
1338 | reschedule callback will be called with the watcher as first, and the |
1102 | current time as second argument. |
1339 | current time as second argument. |
1103 | .Sp |
1340 | .Sp |
1104 | \&\s-1NOTE:\s0 \fIThis callback \s-1MUST\s0 \s-1NOT\s0 stop or destroy any periodic watcher, |
1341 | \&\s-1NOTE:\s0 \fIThis callback \s-1MUST\s0 \s-1NOT\s0 stop or destroy any periodic watcher, |
1105 | ever, or make any event loop modifications\fR. If you need to stop it, |
1342 | ever, or make any event loop modifications\fR. If you need to stop it, |
1106 | return \f(CW\*(C`now + 1e30\*(C'\fR (or so, fudge fudge) and stop it afterwards (e.g. by |
1343 | return \f(CW\*(C`now + 1e30\*(C'\fR (or so, fudge fudge) and stop it afterwards (e.g. by |
1107 | starting a prepare watcher). |
1344 | starting an \f(CW\*(C`ev_prepare\*(C'\fR watcher, which is legal). |
1108 | .Sp |
1345 | .Sp |
1109 | Its prototype is \f(CW\*(C`ev_tstamp (*reschedule_cb)(struct ev_periodic *w, |
1346 | Its prototype is \f(CW\*(C`ev_tstamp (*reschedule_cb)(struct ev_periodic *w, |
1110 | ev_tstamp now)\*(C'\fR, e.g.: |
1347 | ev_tstamp now)\*(C'\fR, e.g.: |
1111 | .Sp |
1348 | .Sp |
1112 | .Vb 4 |
1349 | .Vb 4 |
… | |
… | |
1136 | .IX Item "ev_periodic_again (loop, ev_periodic *)" |
1373 | .IX Item "ev_periodic_again (loop, ev_periodic *)" |
1137 | Simply stops and restarts the periodic watcher again. This is only useful |
1374 | Simply stops and restarts the periodic watcher again. This is only useful |
1138 | when you changed some parameters or the reschedule callback would return |
1375 | when you changed some parameters or the reschedule callback would return |
1139 | a different time than the last time it was called (e.g. in a crond like |
1376 | a different time than the last time it was called (e.g. in a crond like |
1140 | program when the crontabs have changed). |
1377 | program when the crontabs have changed). |
|
|
1378 | .IP "ev_tstamp offset [read\-write]" 4 |
|
|
1379 | .IX Item "ev_tstamp offset [read-write]" |
|
|
1380 | When repeating, this contains the offset value, otherwise this is the |
|
|
1381 | absolute point in time (the \f(CW\*(C`at\*(C'\fR value passed to \f(CW\*(C`ev_periodic_set\*(C'\fR). |
|
|
1382 | .Sp |
|
|
1383 | Can be modified any time, but changes only take effect when the periodic |
|
|
1384 | timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called. |
1141 | .IP "ev_tstamp interval [read\-write]" 4 |
1385 | .IP "ev_tstamp interval [read\-write]" 4 |
1142 | .IX Item "ev_tstamp interval [read-write]" |
1386 | .IX Item "ev_tstamp interval [read-write]" |
1143 | The current interval value. Can be modified any time, but changes only |
1387 | The current interval value. Can be modified any time, but changes only |
1144 | take effect when the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being |
1388 | take effect when the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being |
1145 | called. |
1389 | called. |
1146 | .IP "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read\-write]" 4 |
1390 | .IP "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read\-write]" 4 |
1147 | .IX Item "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write]" |
1391 | .IX Item "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write]" |
1148 | The current reschedule callback, or \f(CW0\fR, if this functionality is |
1392 | The current reschedule callback, or \f(CW0\fR, if this functionality is |
1149 | switched off. Can be changed any time, but changes only take effect when |
1393 | switched off. Can be changed any time, but changes only take effect when |
1150 | the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called. |
1394 | the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called. |
|
|
1395 | .IP "ev_tstamp at [read\-only]" 4 |
|
|
1396 | .IX Item "ev_tstamp at [read-only]" |
|
|
1397 | When active, contains the absolute time that the watcher is supposed to |
|
|
1398 | trigger next. |
1151 | .PP |
1399 | .PP |
1152 | Example: call a callback every hour, or, more precisely, whenever the |
1400 | Example: Call a callback every hour, or, more precisely, whenever the |
1153 | system clock is divisible by 3600. The callback invocation times have |
1401 | system clock is divisible by 3600. The callback invocation times have |
1154 | potentially a lot of jittering, but good long-term stability. |
1402 | potentially a lot of jittering, but good long-term stability. |
1155 | .PP |
1403 | .PP |
1156 | .Vb 5 |
1404 | .Vb 5 |
1157 | \& static void |
1405 | \& static void |
… | |
… | |
1165 | \& struct ev_periodic hourly_tick; |
1413 | \& struct ev_periodic hourly_tick; |
1166 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); |
1414 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); |
1167 | \& ev_periodic_start (loop, &hourly_tick); |
1415 | \& ev_periodic_start (loop, &hourly_tick); |
1168 | .Ve |
1416 | .Ve |
1169 | .PP |
1417 | .PP |
1170 | Example: the same as above, but use a reschedule callback to do it: |
1418 | Example: The same as above, but use a reschedule callback to do it: |
1171 | .PP |
1419 | .PP |
1172 | .Vb 1 |
1420 | .Vb 1 |
1173 | \& #include <math.h> |
1421 | \& #include <math.h> |
1174 | .Ve |
1422 | .Ve |
1175 | .PP |
1423 | .PP |
… | |
… | |
1183 | .PP |
1431 | .PP |
1184 | .Vb 1 |
1432 | .Vb 1 |
1185 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); |
1433 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); |
1186 | .Ve |
1434 | .Ve |
1187 | .PP |
1435 | .PP |
1188 | Example: call a callback every hour, starting now: |
1436 | Example: Call a callback every hour, starting now: |
1189 | .PP |
1437 | .PP |
1190 | .Vb 4 |
1438 | .Vb 4 |
1191 | \& struct ev_periodic hourly_tick; |
1439 | \& struct ev_periodic hourly_tick; |
1192 | \& ev_periodic_init (&hourly_tick, clock_cb, |
1440 | \& ev_periodic_init (&hourly_tick, clock_cb, |
1193 | \& fmod (ev_now (loop), 3600.), 3600., 0); |
1441 | \& fmod (ev_now (loop), 3600.), 3600., 0); |
… | |
… | |
1205 | first watcher gets started will libev actually register a signal watcher |
1453 | first watcher gets started will libev actually register a signal watcher |
1206 | with the kernel (thus it coexists with your own signal handlers as long |
1454 | with the kernel (thus it coexists with your own signal handlers as long |
1207 | as you don't register any with libev). Similarly, when the last signal |
1455 | as you don't register any with libev). Similarly, when the last signal |
1208 | watcher for a signal is stopped libev will reset the signal handler to |
1456 | watcher for a signal is stopped libev will reset the signal handler to |
1209 | \&\s-1SIG_DFL\s0 (regardless of what it was set to before). |
1457 | \&\s-1SIG_DFL\s0 (regardless of what it was set to before). |
|
|
1458 | .PP |
|
|
1459 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1460 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1210 | .IP "ev_signal_init (ev_signal *, callback, int signum)" 4 |
1461 | .IP "ev_signal_init (ev_signal *, callback, int signum)" 4 |
1211 | .IX Item "ev_signal_init (ev_signal *, callback, int signum)" |
1462 | .IX Item "ev_signal_init (ev_signal *, callback, int signum)" |
1212 | .PD 0 |
1463 | .PD 0 |
1213 | .IP "ev_signal_set (ev_signal *, int signum)" 4 |
1464 | .IP "ev_signal_set (ev_signal *, int signum)" 4 |
1214 | .IX Item "ev_signal_set (ev_signal *, int signum)" |
1465 | .IX Item "ev_signal_set (ev_signal *, int signum)" |
… | |
… | |
1221 | .ie n .Sh """ev_child"" \- watch out for process status changes" |
1472 | .ie n .Sh """ev_child"" \- watch out for process status changes" |
1222 | .el .Sh "\f(CWev_child\fP \- watch out for process status changes" |
1473 | .el .Sh "\f(CWev_child\fP \- watch out for process status changes" |
1223 | .IX Subsection "ev_child - watch out for process status changes" |
1474 | .IX Subsection "ev_child - watch out for process status changes" |
1224 | Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to |
1475 | Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to |
1225 | some child status changes (most typically when a child of yours dies). |
1476 | some child status changes (most typically when a child of yours dies). |
|
|
1477 | .PP |
|
|
1478 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1479 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1226 | .IP "ev_child_init (ev_child *, callback, int pid)" 4 |
1480 | .IP "ev_child_init (ev_child *, callback, int pid)" 4 |
1227 | .IX Item "ev_child_init (ev_child *, callback, int pid)" |
1481 | .IX Item "ev_child_init (ev_child *, callback, int pid)" |
1228 | .PD 0 |
1482 | .PD 0 |
1229 | .IP "ev_child_set (ev_child *, int pid)" 4 |
1483 | .IP "ev_child_set (ev_child *, int pid)" 4 |
1230 | .IX Item "ev_child_set (ev_child *, int pid)" |
1484 | .IX Item "ev_child_set (ev_child *, int pid)" |
… | |
… | |
1244 | .IP "int rstatus [read\-write]" 4 |
1498 | .IP "int rstatus [read\-write]" 4 |
1245 | .IX Item "int rstatus [read-write]" |
1499 | .IX Item "int rstatus [read-write]" |
1246 | The process exit/trace status caused by \f(CW\*(C`rpid\*(C'\fR (see your systems |
1500 | The process exit/trace status caused by \f(CW\*(C`rpid\*(C'\fR (see your systems |
1247 | \&\f(CW\*(C`waitpid\*(C'\fR and \f(CW\*(C`sys/wait.h\*(C'\fR documentation for details). |
1501 | \&\f(CW\*(C`waitpid\*(C'\fR and \f(CW\*(C`sys/wait.h\*(C'\fR documentation for details). |
1248 | .PP |
1502 | .PP |
1249 | Example: try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0. |
1503 | Example: Try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0. |
1250 | .PP |
1504 | .PP |
1251 | .Vb 5 |
1505 | .Vb 5 |
1252 | \& static void |
1506 | \& static void |
1253 | \& sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
1507 | \& sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
1254 | \& { |
1508 | \& { |
… | |
… | |
1272 | not exist\*(R" is a status change like any other. The condition \*(L"path does |
1526 | not exist\*(R" is a status change like any other. The condition \*(L"path does |
1273 | not exist\*(R" is signified by the \f(CW\*(C`st_nlink\*(C'\fR field being zero (which is |
1527 | not exist\*(R" is signified by the \f(CW\*(C`st_nlink\*(C'\fR field being zero (which is |
1274 | otherwise always forced to be at least one) and all the other fields of |
1528 | otherwise always forced to be at least one) and all the other fields of |
1275 | the stat buffer having unspecified contents. |
1529 | the stat buffer having unspecified contents. |
1276 | .PP |
1530 | .PP |
|
|
1531 | The path \fIshould\fR be absolute and \fImust not\fR end in a slash. If it is |
|
|
1532 | relative and your working directory changes, the behaviour is undefined. |
|
|
1533 | .PP |
1277 | Since there is no standard to do this, the portable implementation simply |
1534 | Since there is no standard to do this, the portable implementation simply |
1278 | calls \f(CW\*(C`stat (2)\*(C'\fR regulalry on the path to see if it changed somehow. You |
1535 | calls \f(CW\*(C`stat (2)\*(C'\fR regularly on the path to see if it changed somehow. You |
1279 | can specify a recommended polling interval for this case. If you specify |
1536 | can specify a recommended polling interval for this case. If you specify |
1280 | a polling interval of \f(CW0\fR (highly recommended!) then a \fIsuitable, |
1537 | a polling interval of \f(CW0\fR (highly recommended!) then a \fIsuitable, |
1281 | unspecified default\fR value will be used (which you can expect to be around |
1538 | unspecified default\fR value will be used (which you can expect to be around |
1282 | five seconds, although this might change dynamically). Libev will also |
1539 | five seconds, although this might change dynamically). Libev will also |
1283 | impose a minimum interval which is currently around \f(CW0.1\fR, but thats |
1540 | impose a minimum interval which is currently around \f(CW0.1\fR, but thats |
… | |
… | |
1285 | .PP |
1542 | .PP |
1286 | This watcher type is not meant for massive numbers of stat watchers, |
1543 | This watcher type is not meant for massive numbers of stat watchers, |
1287 | as even with OS-supported change notifications, this can be |
1544 | as even with OS-supported change notifications, this can be |
1288 | resource\-intensive. |
1545 | resource\-intensive. |
1289 | .PP |
1546 | .PP |
1290 | At the time of this writing, no specific \s-1OS\s0 backends are implemented, but |
1547 | At the time of this writing, only the Linux inotify interface is |
1291 | if demand increases, at least a kqueue and inotify backend will be added. |
1548 | implemented (implementing kqueue support is left as an exercise for the |
|
|
1549 | reader). Inotify will be used to give hints only and should not change the |
|
|
1550 | semantics of \f(CW\*(C`ev_stat\*(C'\fR watchers, which means that libev sometimes needs |
|
|
1551 | to fall back to regular polling again even with inotify, but changes are |
|
|
1552 | usually detected immediately, and if the file exists there will be no |
|
|
1553 | polling. |
|
|
1554 | .PP |
|
|
1555 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1556 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1292 | .IP "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" 4 |
1557 | .IP "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" 4 |
1293 | .IX Item "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" |
1558 | .IX Item "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" |
1294 | .PD 0 |
1559 | .PD 0 |
1295 | .IP "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" 4 |
1560 | .IP "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" 4 |
1296 | .IX Item "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" |
1561 | .IX Item "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" |
… | |
… | |
1357 | \& ev_stat_start (loop, &passwd); |
1622 | \& ev_stat_start (loop, &passwd); |
1358 | .Ve |
1623 | .Ve |
1359 | .ie n .Sh """ev_idle"" \- when you've got nothing better to do..." |
1624 | .ie n .Sh """ev_idle"" \- when you've got nothing better to do..." |
1360 | .el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do..." |
1625 | .el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do..." |
1361 | .IX Subsection "ev_idle - when you've got nothing better to do..." |
1626 | .IX Subsection "ev_idle - when you've got nothing better to do..." |
1362 | Idle watchers trigger events when there are no other events are pending |
1627 | Idle watchers trigger events when no other events of the same or higher |
1363 | (prepare, check and other idle watchers do not count). That is, as long |
1628 | priority are pending (prepare, check and other idle watchers do not |
1364 | as your process is busy handling sockets or timeouts (or even signals, |
1629 | count). |
1365 | imagine) it will not be triggered. But when your process is idle all idle |
1630 | .PP |
1366 | watchers are being called again and again, once per event loop iteration \- |
1631 | That is, as long as your process is busy handling sockets or timeouts |
|
|
1632 | (or even signals, imagine) of the same or higher priority it will not be |
|
|
1633 | triggered. But when your process is idle (or only lower-priority watchers |
|
|
1634 | are pending), the idle watchers are being called once per event loop |
1367 | until stopped, that is, or your process receives more events and becomes |
1635 | iteration \- until stopped, that is, or your process receives more events |
1368 | busy. |
1636 | and becomes busy again with higher priority stuff. |
1369 | .PP |
1637 | .PP |
1370 | The most noteworthy effect is that as long as any idle watchers are |
1638 | The most noteworthy effect is that as long as any idle watchers are |
1371 | active, the process will not block when waiting for new events. |
1639 | active, the process will not block when waiting for new events. |
1372 | .PP |
1640 | .PP |
1373 | Apart from keeping your process non-blocking (which is a useful |
1641 | Apart from keeping your process non-blocking (which is a useful |
1374 | effect on its own sometimes), idle watchers are a good place to do |
1642 | effect on its own sometimes), idle watchers are a good place to do |
1375 | \&\*(L"pseudo\-background processing\*(R", or delay processing stuff to after the |
1643 | \&\*(L"pseudo\-background processing\*(R", or delay processing stuff to after the |
1376 | event loop has handled all outstanding events. |
1644 | event loop has handled all outstanding events. |
|
|
1645 | .PP |
|
|
1646 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1647 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1377 | .IP "ev_idle_init (ev_signal *, callback)" 4 |
1648 | .IP "ev_idle_init (ev_signal *, callback)" 4 |
1378 | .IX Item "ev_idle_init (ev_signal *, callback)" |
1649 | .IX Item "ev_idle_init (ev_signal *, callback)" |
1379 | Initialises and configures the idle watcher \- it has no parameters of any |
1650 | Initialises and configures the idle watcher \- it has no parameters of any |
1380 | kind. There is a \f(CW\*(C`ev_idle_set\*(C'\fR macro, but using it is utterly pointless, |
1651 | kind. There is a \f(CW\*(C`ev_idle_set\*(C'\fR macro, but using it is utterly pointless, |
1381 | believe me. |
1652 | believe me. |
1382 | .PP |
1653 | .PP |
1383 | Example: dynamically allocate an \f(CW\*(C`ev_idle\*(C'\fR, start it, and in the |
1654 | Example: Dynamically allocate an \f(CW\*(C`ev_idle\*(C'\fR watcher, start it, and in the |
1384 | callback, free it. Alos, use no error checking, as usual. |
1655 | callback, free it. Also, use no error checking, as usual. |
1385 | .PP |
1656 | .PP |
1386 | .Vb 7 |
1657 | .Vb 7 |
1387 | \& static void |
1658 | \& static void |
1388 | \& idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
1659 | \& idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
1389 | \& { |
1660 | \& { |
… | |
… | |
1436 | are ready to run (it's actually more complicated: it only runs coroutines |
1707 | are ready to run (it's actually more complicated: it only runs coroutines |
1437 | with priority higher than or equal to the event loop and one coroutine |
1708 | with priority higher than or equal to the event loop and one coroutine |
1438 | of lower priority, but only once, using idle watchers to keep the event |
1709 | of lower priority, but only once, using idle watchers to keep the event |
1439 | loop from blocking if lower-priority coroutines are active, thus mapping |
1710 | loop from blocking if lower-priority coroutines are active, thus mapping |
1440 | low-priority coroutines to idle/background tasks). |
1711 | low-priority coroutines to idle/background tasks). |
|
|
1712 | .PP |
|
|
1713 | It is recommended to give \f(CW\*(C`ev_check\*(C'\fR watchers highest (\f(CW\*(C`EV_MAXPRI\*(C'\fR) |
|
|
1714 | priority, to ensure that they are being run before any other watchers |
|
|
1715 | after the poll. Also, \f(CW\*(C`ev_check\*(C'\fR watchers (and \f(CW\*(C`ev_prepare\*(C'\fR watchers, |
|
|
1716 | too) should not activate (\*(L"feed\*(R") events into libev. While libev fully |
|
|
1717 | supports this, they will be called before other \f(CW\*(C`ev_check\*(C'\fR watchers did |
|
|
1718 | their job. As \f(CW\*(C`ev_check\*(C'\fR watchers are often used to embed other event |
|
|
1719 | loops those other event loops might be in an unusable state until their |
|
|
1720 | \&\f(CW\*(C`ev_check\*(C'\fR watcher ran (always remind yourself to coexist peacefully with |
|
|
1721 | others). |
|
|
1722 | .PP |
|
|
1723 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1724 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1441 | .IP "ev_prepare_init (ev_prepare *, callback)" 4 |
1725 | .IP "ev_prepare_init (ev_prepare *, callback)" 4 |
1442 | .IX Item "ev_prepare_init (ev_prepare *, callback)" |
1726 | .IX Item "ev_prepare_init (ev_prepare *, callback)" |
1443 | .PD 0 |
1727 | .PD 0 |
1444 | .IP "ev_check_init (ev_check *, callback)" 4 |
1728 | .IP "ev_check_init (ev_check *, callback)" 4 |
1445 | .IX Item "ev_check_init (ev_check *, callback)" |
1729 | .IX Item "ev_check_init (ev_check *, callback)" |
1446 | .PD |
1730 | .PD |
1447 | Initialises and configures the prepare or check watcher \- they have no |
1731 | Initialises and configures the prepare or check watcher \- they have no |
1448 | parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR |
1732 | parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR |
1449 | macros, but using them is utterly, utterly and completely pointless. |
1733 | macros, but using them is utterly, utterly and completely pointless. |
1450 | .PP |
1734 | .PP |
1451 | Example: To include a library such as adns, you would add \s-1IO\s0 watchers |
1735 | There are a number of principal ways to embed other event loops or modules |
1452 | and a timeout watcher in a prepare handler, as required by libadns, and |
1736 | into libev. Here are some ideas on how to include libadns into libev |
|
|
1737 | (there is a Perl module named \f(CW\*(C`EV::ADNS\*(C'\fR that does this, which you could |
|
|
1738 | use for an actually working example. Another Perl module named \f(CW\*(C`EV::Glib\*(C'\fR |
|
|
1739 | embeds a Glib main context into libev, and finally, \f(CW\*(C`Glib::EV\*(C'\fR embeds \s-1EV\s0 |
|
|
1740 | into the Glib event loop). |
|
|
1741 | .PP |
|
|
1742 | Method 1: Add \s-1IO\s0 watchers and a timeout watcher in a prepare handler, |
1453 | in a check watcher, destroy them and call into libadns. What follows is |
1743 | and in a check watcher, destroy them and call into libadns. What follows |
1454 | pseudo-code only of course: |
1744 | is pseudo-code only of course. This requires you to either use a low |
|
|
1745 | priority for the check watcher or use \f(CW\*(C`ev_clear_pending\*(C'\fR explicitly, as |
|
|
1746 | the callbacks for the IO/timeout watchers might not have been called yet. |
1455 | .PP |
1747 | .PP |
1456 | .Vb 2 |
1748 | .Vb 2 |
1457 | \& static ev_io iow [nfd]; |
1749 | \& static ev_io iow [nfd]; |
1458 | \& static ev_timer tw; |
1750 | \& static ev_timer tw; |
1459 | .Ve |
1751 | .Ve |
1460 | .PP |
1752 | .PP |
1461 | .Vb 9 |
1753 | .Vb 4 |
1462 | \& static void |
1754 | \& static void |
1463 | \& io_cb (ev_loop *loop, ev_io *w, int revents) |
1755 | \& io_cb (ev_loop *loop, ev_io *w, int revents) |
1464 | \& { |
1756 | \& { |
1465 | \& // set the relevant poll flags |
|
|
1466 | \& // could also call adns_processreadable etc. here |
|
|
1467 | \& struct pollfd *fd = (struct pollfd *)w->data; |
|
|
1468 | \& if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
|
|
1469 | \& if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
|
|
1470 | \& } |
1757 | \& } |
1471 | .Ve |
1758 | .Ve |
1472 | .PP |
1759 | .PP |
1473 | .Vb 7 |
1760 | .Vb 8 |
1474 | \& // create io watchers for each fd and a timer before blocking |
1761 | \& // create io watchers for each fd and a timer before blocking |
1475 | \& static void |
1762 | \& static void |
1476 | \& adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
1763 | \& adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
1477 | \& { |
1764 | \& { |
1478 | \& int timeout = 3600000;truct pollfd fds [nfd]; |
1765 | \& int timeout = 3600000; |
|
|
1766 | \& struct pollfd fds [nfd]; |
1479 | \& // actual code will need to loop here and realloc etc. |
1767 | \& // actual code will need to loop here and realloc etc. |
1480 | \& adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
1768 | \& adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
1481 | .Ve |
1769 | .Ve |
1482 | .PP |
1770 | .PP |
1483 | .Vb 3 |
1771 | .Vb 3 |
… | |
… | |
1485 | \& ev_timer_init (&tw, 0, timeout * 1e-3); |
1773 | \& ev_timer_init (&tw, 0, timeout * 1e-3); |
1486 | \& ev_timer_start (loop, &tw); |
1774 | \& ev_timer_start (loop, &tw); |
1487 | .Ve |
1775 | .Ve |
1488 | .PP |
1776 | .PP |
1489 | .Vb 6 |
1777 | .Vb 6 |
1490 | \& // create on ev_io per pollfd |
1778 | \& // create one ev_io per pollfd |
1491 | \& for (int i = 0; i < nfd; ++i) |
1779 | \& for (int i = 0; i < nfd; ++i) |
1492 | \& { |
1780 | \& { |
1493 | \& ev_io_init (iow + i, io_cb, fds [i].fd, |
1781 | \& ev_io_init (iow + i, io_cb, fds [i].fd, |
1494 | \& ((fds [i].events & POLLIN ? EV_READ : 0) |
1782 | \& ((fds [i].events & POLLIN ? EV_READ : 0) |
1495 | \& | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
1783 | \& | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
1496 | .Ve |
1784 | .Ve |
1497 | .PP |
1785 | .PP |
1498 | .Vb 5 |
1786 | .Vb 4 |
1499 | \& fds [i].revents = 0; |
1787 | \& fds [i].revents = 0; |
1500 | \& iow [i].data = fds + i; |
|
|
1501 | \& ev_io_start (loop, iow + i); |
1788 | \& ev_io_start (loop, iow + i); |
1502 | \& } |
1789 | \& } |
1503 | \& } |
1790 | \& } |
1504 | .Ve |
1791 | .Ve |
1505 | .PP |
1792 | .PP |
… | |
… | |
1509 | \& adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
1796 | \& adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
1510 | \& { |
1797 | \& { |
1511 | \& ev_timer_stop (loop, &tw); |
1798 | \& ev_timer_stop (loop, &tw); |
1512 | .Ve |
1799 | .Ve |
1513 | .PP |
1800 | .PP |
1514 | .Vb 2 |
1801 | .Vb 8 |
1515 | \& for (int i = 0; i < nfd; ++i) |
1802 | \& for (int i = 0; i < nfd; ++i) |
|
|
1803 | \& { |
|
|
1804 | \& // set the relevant poll flags |
|
|
1805 | \& // could also call adns_processreadable etc. here |
|
|
1806 | \& struct pollfd *fd = fds + i; |
|
|
1807 | \& int revents = ev_clear_pending (iow + i); |
|
|
1808 | \& if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
|
|
1809 | \& if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
|
|
1810 | .Ve |
|
|
1811 | .PP |
|
|
1812 | .Vb 3 |
|
|
1813 | \& // now stop the watcher |
1516 | \& ev_io_stop (loop, iow + i); |
1814 | \& ev_io_stop (loop, iow + i); |
|
|
1815 | \& } |
1517 | .Ve |
1816 | .Ve |
1518 | .PP |
1817 | .PP |
1519 | .Vb 2 |
1818 | .Vb 2 |
1520 | \& adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
1819 | \& adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
|
|
1820 | \& } |
|
|
1821 | .Ve |
|
|
1822 | .PP |
|
|
1823 | Method 2: This would be just like method 1, but you run \f(CW\*(C`adns_afterpoll\*(C'\fR |
|
|
1824 | in the prepare watcher and would dispose of the check watcher. |
|
|
1825 | .PP |
|
|
1826 | Method 3: If the module to be embedded supports explicit event |
|
|
1827 | notification (adns does), you can also make use of the actual watcher |
|
|
1828 | callbacks, and only destroy/create the watchers in the prepare watcher. |
|
|
1829 | .PP |
|
|
1830 | .Vb 5 |
|
|
1831 | \& static void |
|
|
1832 | \& timer_cb (EV_P_ ev_timer *w, int revents) |
|
|
1833 | \& { |
|
|
1834 | \& adns_state ads = (adns_state)w->data; |
|
|
1835 | \& update_now (EV_A); |
|
|
1836 | .Ve |
|
|
1837 | .PP |
|
|
1838 | .Vb 2 |
|
|
1839 | \& adns_processtimeouts (ads, &tv_now); |
|
|
1840 | \& } |
|
|
1841 | .Ve |
|
|
1842 | .PP |
|
|
1843 | .Vb 5 |
|
|
1844 | \& static void |
|
|
1845 | \& io_cb (EV_P_ ev_io *w, int revents) |
|
|
1846 | \& { |
|
|
1847 | \& adns_state ads = (adns_state)w->data; |
|
|
1848 | \& update_now (EV_A); |
|
|
1849 | .Ve |
|
|
1850 | .PP |
|
|
1851 | .Vb 3 |
|
|
1852 | \& if (revents & EV_READ ) adns_processreadable (ads, w->fd, &tv_now); |
|
|
1853 | \& if (revents & EV_WRITE) adns_processwriteable (ads, w->fd, &tv_now); |
|
|
1854 | \& } |
|
|
1855 | .Ve |
|
|
1856 | .PP |
|
|
1857 | .Vb 1 |
|
|
1858 | \& // do not ever call adns_afterpoll |
|
|
1859 | .Ve |
|
|
1860 | .PP |
|
|
1861 | Method 4: Do not use a prepare or check watcher because the module you |
|
|
1862 | want to embed is too inflexible to support it. Instead, youc na override |
|
|
1863 | their poll function. The drawback with this solution is that the main |
|
|
1864 | loop is now no longer controllable by \s-1EV\s0. The \f(CW\*(C`Glib::EV\*(C'\fR module does |
|
|
1865 | this. |
|
|
1866 | .PP |
|
|
1867 | .Vb 4 |
|
|
1868 | \& static gint |
|
|
1869 | \& event_poll_func (GPollFD *fds, guint nfds, gint timeout) |
|
|
1870 | \& { |
|
|
1871 | \& int got_events = 0; |
|
|
1872 | .Ve |
|
|
1873 | .PP |
|
|
1874 | .Vb 2 |
|
|
1875 | \& for (n = 0; n < nfds; ++n) |
|
|
1876 | \& // create/start io watcher that sets the relevant bits in fds[n] and increment got_events |
|
|
1877 | .Ve |
|
|
1878 | .PP |
|
|
1879 | .Vb 2 |
|
|
1880 | \& if (timeout >= 0) |
|
|
1881 | \& // create/start timer |
|
|
1882 | .Ve |
|
|
1883 | .PP |
|
|
1884 | .Vb 2 |
|
|
1885 | \& // poll |
|
|
1886 | \& ev_loop (EV_A_ 0); |
|
|
1887 | .Ve |
|
|
1888 | .PP |
|
|
1889 | .Vb 3 |
|
|
1890 | \& // stop timer again |
|
|
1891 | \& if (timeout >= 0) |
|
|
1892 | \& ev_timer_stop (EV_A_ &to); |
|
|
1893 | .Ve |
|
|
1894 | .PP |
|
|
1895 | .Vb 3 |
|
|
1896 | \& // stop io watchers again - their callbacks should have set |
|
|
1897 | \& for (n = 0; n < nfds; ++n) |
|
|
1898 | \& ev_io_stop (EV_A_ iow [n]); |
|
|
1899 | .Ve |
|
|
1900 | .PP |
|
|
1901 | .Vb 2 |
|
|
1902 | \& return got_events; |
1521 | \& } |
1903 | \& } |
1522 | .Ve |
1904 | .Ve |
1523 | .ie n .Sh """ev_embed"" \- when one backend isn't enough..." |
1905 | .ie n .Sh """ev_embed"" \- when one backend isn't enough..." |
1524 | .el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..." |
1906 | .el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..." |
1525 | .IX Subsection "ev_embed - when one backend isn't enough..." |
1907 | .IX Subsection "ev_embed - when one backend isn't enough..." |
… | |
… | |
1594 | \& ev_embed_start (loop_hi, &embed); |
1976 | \& ev_embed_start (loop_hi, &embed); |
1595 | \& } |
1977 | \& } |
1596 | \& else |
1978 | \& else |
1597 | \& loop_lo = loop_hi; |
1979 | \& loop_lo = loop_hi; |
1598 | .Ve |
1980 | .Ve |
|
|
1981 | .PP |
|
|
1982 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1983 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1599 | .IP "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
1984 | .IP "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
1600 | .IX Item "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" |
1985 | .IX Item "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" |
1601 | .PD 0 |
1986 | .PD 0 |
1602 | .IP "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
1987 | .IP "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
1603 | .IX Item "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" |
1988 | .IX Item "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" |
… | |
… | |
1613 | similarly to \f(CW\*(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\*(C'\fR, but in the most |
1998 | similarly to \f(CW\*(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\*(C'\fR, but in the most |
1614 | apropriate way for embedded loops. |
1999 | apropriate way for embedded loops. |
1615 | .IP "struct ev_loop *loop [read\-only]" 4 |
2000 | .IP "struct ev_loop *loop [read\-only]" 4 |
1616 | .IX Item "struct ev_loop *loop [read-only]" |
2001 | .IX Item "struct ev_loop *loop [read-only]" |
1617 | The embedded event loop. |
2002 | The embedded event loop. |
|
|
2003 | .ie n .Sh """ev_fork"" \- the audacity to resume the event loop after a fork" |
|
|
2004 | .el .Sh "\f(CWev_fork\fP \- the audacity to resume the event loop after a fork" |
|
|
2005 | .IX Subsection "ev_fork - the audacity to resume the event loop after a fork" |
|
|
2006 | Fork watchers are called when a \f(CW\*(C`fork ()\*(C'\fR was detected (usually because |
|
|
2007 | whoever is a good citizen cared to tell libev about it by calling |
|
|
2008 | \&\f(CW\*(C`ev_default_fork\*(C'\fR or \f(CW\*(C`ev_loop_fork\*(C'\fR). The invocation is done before the |
|
|
2009 | event loop blocks next and before \f(CW\*(C`ev_check\*(C'\fR watchers are being called, |
|
|
2010 | and only in the child after the fork. If whoever good citizen calling |
|
|
2011 | \&\f(CW\*(C`ev_default_fork\*(C'\fR cheats and calls it in the wrong process, the fork |
|
|
2012 | handlers will be invoked, too, of course. |
|
|
2013 | .PP |
|
|
2014 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
2015 | .IX Subsection "Watcher-Specific Functions and Data Members" |
|
|
2016 | .IP "ev_fork_init (ev_signal *, callback)" 4 |
|
|
2017 | .IX Item "ev_fork_init (ev_signal *, callback)" |
|
|
2018 | Initialises and configures the fork watcher \- it has no parameters of any |
|
|
2019 | kind. There is a \f(CW\*(C`ev_fork_set\*(C'\fR macro, but using it is utterly pointless, |
|
|
2020 | believe me. |
1618 | .SH "OTHER FUNCTIONS" |
2021 | .SH "OTHER FUNCTIONS" |
1619 | .IX Header "OTHER FUNCTIONS" |
2022 | .IX Header "OTHER FUNCTIONS" |
1620 | There are some other functions of possible interest. Described. Here. Now. |
2023 | There are some other functions of possible interest. Described. Here. Now. |
1621 | .IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4 |
2024 | .IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4 |
1622 | .IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" |
2025 | .IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" |
… | |
… | |
1694 | .PP |
2097 | .PP |
1695 | .Vb 1 |
2098 | .Vb 1 |
1696 | \& #include <ev++.h> |
2099 | \& #include <ev++.h> |
1697 | .Ve |
2100 | .Ve |
1698 | .PP |
2101 | .PP |
1699 | (it is not installed by default). This automatically includes \fIev.h\fR |
2102 | This automatically includes \fIev.h\fR and puts all of its definitions (many |
1700 | and puts all of its definitions (many of them macros) into the global |
2103 | of them macros) into the global namespace. All \*(C+ specific things are |
1701 | namespace. All \*(C+ specific things are put into the \f(CW\*(C`ev\*(C'\fR namespace. |
2104 | put into the \f(CW\*(C`ev\*(C'\fR namespace. It should support all the same embedding |
|
|
2105 | options as \fIev.h\fR, most notably \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. |
1702 | .PP |
2106 | .PP |
1703 | It should support all the same embedding options as \fIev.h\fR, most notably |
2107 | Care has been taken to keep the overhead low. The only data member the \*(C+ |
1704 | \&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. |
2108 | classes add (compared to plain C\-style watchers) is the event loop pointer |
|
|
2109 | that the watcher is associated with (or no additional members at all if |
|
|
2110 | you disable \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR when embedding libev). |
|
|
2111 | .PP |
|
|
2112 | Currently, functions, and static and non-static member functions can be |
|
|
2113 | used as callbacks. Other types should be easy to add as long as they only |
|
|
2114 | need one additional pointer for context. If you need support for other |
|
|
2115 | types of functors please contact the author (preferably after implementing |
|
|
2116 | it). |
1705 | .PP |
2117 | .PP |
1706 | Here is a list of things available in the \f(CW\*(C`ev\*(C'\fR namespace: |
2118 | Here is a list of things available in the \f(CW\*(C`ev\*(C'\fR namespace: |
1707 | .ie n .IP """ev::READ""\fR, \f(CW""ev::WRITE"" etc." 4 |
2119 | .ie n .IP """ev::READ""\fR, \f(CW""ev::WRITE"" etc." 4 |
1708 | .el .IP "\f(CWev::READ\fR, \f(CWev::WRITE\fR etc." 4 |
2120 | .el .IP "\f(CWev::READ\fR, \f(CWev::WRITE\fR etc." 4 |
1709 | .IX Item "ev::READ, ev::WRITE etc." |
2121 | .IX Item "ev::READ, ev::WRITE etc." |
… | |
… | |
1721 | which is called \f(CW\*(C`ev::sig\*(C'\fR to avoid clashes with the \f(CW\*(C`signal\*(C'\fR macro |
2133 | which is called \f(CW\*(C`ev::sig\*(C'\fR to avoid clashes with the \f(CW\*(C`signal\*(C'\fR macro |
1722 | defines by many implementations. |
2134 | defines by many implementations. |
1723 | .Sp |
2135 | .Sp |
1724 | All of those classes have these methods: |
2136 | All of those classes have these methods: |
1725 | .RS 4 |
2137 | .RS 4 |
1726 | .IP "ev::TYPE::TYPE (object *, object::method *)" 4 |
2138 | .IP "ev::TYPE::TYPE ()" 4 |
1727 | .IX Item "ev::TYPE::TYPE (object *, object::method *)" |
2139 | .IX Item "ev::TYPE::TYPE ()" |
1728 | .PD 0 |
2140 | .PD 0 |
1729 | .IP "ev::TYPE::TYPE (object *, object::method *, struct ev_loop *)" 4 |
2141 | .IP "ev::TYPE::TYPE (struct ev_loop *)" 4 |
1730 | .IX Item "ev::TYPE::TYPE (object *, object::method *, struct ev_loop *)" |
2142 | .IX Item "ev::TYPE::TYPE (struct ev_loop *)" |
1731 | .IP "ev::TYPE::~TYPE" 4 |
2143 | .IP "ev::TYPE::~TYPE" 4 |
1732 | .IX Item "ev::TYPE::~TYPE" |
2144 | .IX Item "ev::TYPE::~TYPE" |
1733 | .PD |
2145 | .PD |
1734 | The constructor takes a pointer to an object and a method pointer to |
2146 | The constructor (optionally) takes an event loop to associate the watcher |
1735 | the event handler callback to call in this class. The constructor calls |
2147 | with. If it is omitted, it will use \f(CW\*(C`EV_DEFAULT\*(C'\fR. |
1736 | \&\f(CW\*(C`ev_init\*(C'\fR for you, which means you have to call the \f(CW\*(C`set\*(C'\fR method |
2148 | .Sp |
1737 | before starting it. If you do not specify a loop then the constructor |
2149 | The constructor calls \f(CW\*(C`ev_init\*(C'\fR for you, which means you have to call the |
1738 | automatically associates the default loop with this watcher. |
2150 | \&\f(CW\*(C`set\*(C'\fR method before starting it. |
|
|
2151 | .Sp |
|
|
2152 | It will not set a callback, however: You have to call the templated \f(CW\*(C`set\*(C'\fR |
|
|
2153 | method to set a callback before you can start the watcher. |
|
|
2154 | .Sp |
|
|
2155 | (The reason why you have to use a method is a limitation in \*(C+ which does |
|
|
2156 | not allow explicit template arguments for constructors). |
1739 | .Sp |
2157 | .Sp |
1740 | The destructor automatically stops the watcher if it is active. |
2158 | The destructor automatically stops the watcher if it is active. |
|
|
2159 | .IP "w\->set<class, &class::method> (object *)" 4 |
|
|
2160 | .IX Item "w->set<class, &class::method> (object *)" |
|
|
2161 | This method sets the callback method to call. The method has to have a |
|
|
2162 | signature of \f(CW\*(C`void (*)(ev_TYPE &, int)\*(C'\fR, it receives the watcher as |
|
|
2163 | first argument and the \f(CW\*(C`revents\*(C'\fR as second. The object must be given as |
|
|
2164 | parameter and is stored in the \f(CW\*(C`data\*(C'\fR member of the watcher. |
|
|
2165 | .Sp |
|
|
2166 | This method synthesizes efficient thunking code to call your method from |
|
|
2167 | the C callback that libev requires. If your compiler can inline your |
|
|
2168 | callback (i.e. it is visible to it at the place of the \f(CW\*(C`set\*(C'\fR call and |
|
|
2169 | your compiler is good :), then the method will be fully inlined into the |
|
|
2170 | thunking function, making it as fast as a direct C callback. |
|
|
2171 | .Sp |
|
|
2172 | Example: simple class declaration and watcher initialisation |
|
|
2173 | .Sp |
|
|
2174 | .Vb 4 |
|
|
2175 | \& struct myclass |
|
|
2176 | \& { |
|
|
2177 | \& void io_cb (ev::io &w, int revents) { } |
|
|
2178 | \& } |
|
|
2179 | .Ve |
|
|
2180 | .Sp |
|
|
2181 | .Vb 3 |
|
|
2182 | \& myclass obj; |
|
|
2183 | \& ev::io iow; |
|
|
2184 | \& iow.set <myclass, &myclass::io_cb> (&obj); |
|
|
2185 | .Ve |
|
|
2186 | .IP "w\->set<function> (void *data = 0)" 4 |
|
|
2187 | .IX Item "w->set<function> (void *data = 0)" |
|
|
2188 | Also sets a callback, but uses a static method or plain function as |
|
|
2189 | callback. The optional \f(CW\*(C`data\*(C'\fR argument will be stored in the watcher's |
|
|
2190 | \&\f(CW\*(C`data\*(C'\fR member and is free for you to use. |
|
|
2191 | .Sp |
|
|
2192 | The prototype of the \f(CW\*(C`function\*(C'\fR must be \f(CW\*(C`void (*)(ev::TYPE &w, int)\*(C'\fR. |
|
|
2193 | .Sp |
|
|
2194 | See the method\-\f(CW\*(C`set\*(C'\fR above for more details. |
|
|
2195 | .Sp |
|
|
2196 | Example: |
|
|
2197 | .Sp |
|
|
2198 | .Vb 2 |
|
|
2199 | \& static void io_cb (ev::io &w, int revents) { } |
|
|
2200 | \& iow.set <io_cb> (); |
|
|
2201 | .Ve |
1741 | .IP "w\->set (struct ev_loop *)" 4 |
2202 | .IP "w\->set (struct ev_loop *)" 4 |
1742 | .IX Item "w->set (struct ev_loop *)" |
2203 | .IX Item "w->set (struct ev_loop *)" |
1743 | Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only |
2204 | Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only |
1744 | do this when the watcher is inactive (and not pending either). |
2205 | do this when the watcher is inactive (and not pending either). |
1745 | .IP "w\->set ([args])" 4 |
2206 | .IP "w\->set ([args])" 4 |
1746 | .IX Item "w->set ([args])" |
2207 | .IX Item "w->set ([args])" |
1747 | Basically the same as \f(CW\*(C`ev_TYPE_set\*(C'\fR, with the same args. Must be |
2208 | Basically the same as \f(CW\*(C`ev_TYPE_set\*(C'\fR, with the same args. Must be |
1748 | called at least once. Unlike the C counterpart, an active watcher gets |
2209 | called at least once. Unlike the C counterpart, an active watcher gets |
1749 | automatically stopped and restarted. |
2210 | automatically stopped and restarted when reconfiguring it with this |
|
|
2211 | method. |
1750 | .IP "w\->start ()" 4 |
2212 | .IP "w\->start ()" 4 |
1751 | .IX Item "w->start ()" |
2213 | .IX Item "w->start ()" |
1752 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument as the |
2214 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument, as the |
1753 | constructor already takes the loop. |
2215 | constructor already stores the event loop. |
1754 | .IP "w\->stop ()" 4 |
2216 | .IP "w\->stop ()" 4 |
1755 | .IX Item "w->stop ()" |
2217 | .IX Item "w->stop ()" |
1756 | Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument. |
2218 | Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument. |
1757 | .ie n .IP "w\->again () ""ev::timer""\fR, \f(CW""ev::periodic"" only" 4 |
2219 | .ie n .IP "w\->again () (""ev::timer""\fR, \f(CW""ev::periodic"" only)" 4 |
1758 | .el .IP "w\->again () \f(CWev::timer\fR, \f(CWev::periodic\fR only" 4 |
2220 | .el .IP "w\->again () (\f(CWev::timer\fR, \f(CWev::periodic\fR only)" 4 |
1759 | .IX Item "w->again () ev::timer, ev::periodic only" |
2221 | .IX Item "w->again () (ev::timer, ev::periodic only)" |
1760 | For \f(CW\*(C`ev::timer\*(C'\fR and \f(CW\*(C`ev::periodic\*(C'\fR, this invokes the corresponding |
2222 | For \f(CW\*(C`ev::timer\*(C'\fR and \f(CW\*(C`ev::periodic\*(C'\fR, this invokes the corresponding |
1761 | \&\f(CW\*(C`ev_TYPE_again\*(C'\fR function. |
2223 | \&\f(CW\*(C`ev_TYPE_again\*(C'\fR function. |
1762 | .ie n .IP "w\->sweep () ""ev::embed"" only" 4 |
2224 | .ie n .IP "w\->sweep () (""ev::embed"" only)" 4 |
1763 | .el .IP "w\->sweep () \f(CWev::embed\fR only" 4 |
2225 | .el .IP "w\->sweep () (\f(CWev::embed\fR only)" 4 |
1764 | .IX Item "w->sweep () ev::embed only" |
2226 | .IX Item "w->sweep () (ev::embed only)" |
1765 | Invokes \f(CW\*(C`ev_embed_sweep\*(C'\fR. |
2227 | Invokes \f(CW\*(C`ev_embed_sweep\*(C'\fR. |
|
|
2228 | .ie n .IP "w\->update () (""ev::stat"" only)" 4 |
|
|
2229 | .el .IP "w\->update () (\f(CWev::stat\fR only)" 4 |
|
|
2230 | .IX Item "w->update () (ev::stat only)" |
|
|
2231 | Invokes \f(CW\*(C`ev_stat_stat\*(C'\fR. |
1766 | .RE |
2232 | .RE |
1767 | .RS 4 |
2233 | .RS 4 |
1768 | .RE |
2234 | .RE |
1769 | .PP |
2235 | .PP |
1770 | Example: Define a class with an \s-1IO\s0 and idle watcher, start one of them in |
2236 | Example: Define a class with an \s-1IO\s0 and idle watcher, start one of them in |
… | |
… | |
1780 | .Vb 2 |
2246 | .Vb 2 |
1781 | \& myclass (); |
2247 | \& myclass (); |
1782 | \& } |
2248 | \& } |
1783 | .Ve |
2249 | .Ve |
1784 | .PP |
2250 | .PP |
1785 | .Vb 6 |
2251 | .Vb 4 |
1786 | \& myclass::myclass (int fd) |
2252 | \& myclass::myclass (int fd) |
1787 | \& : io (this, &myclass::io_cb), |
|
|
1788 | \& idle (this, &myclass::idle_cb) |
|
|
1789 | \& { |
2253 | \& { |
|
|
2254 | \& io .set <myclass, &myclass::io_cb > (this); |
|
|
2255 | \& idle.set <myclass, &myclass::idle_cb> (this); |
|
|
2256 | .Ve |
|
|
2257 | .PP |
|
|
2258 | .Vb 2 |
1790 | \& io.start (fd, ev::READ); |
2259 | \& io.start (fd, ev::READ); |
1791 | \& } |
2260 | \& } |
|
|
2261 | .Ve |
|
|
2262 | .SH "MACRO MAGIC" |
|
|
2263 | .IX Header "MACRO MAGIC" |
|
|
2264 | Libev can be compiled with a variety of options, the most fundamantal |
|
|
2265 | of which is \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines whether (most) |
|
|
2266 | functions and callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument. |
|
|
2267 | .PP |
|
|
2268 | To make it easier to write programs that cope with either variant, the |
|
|
2269 | following macros are defined: |
|
|
2270 | .ie n .IP """EV_A""\fR, \f(CW""EV_A_""" 4 |
|
|
2271 | .el .IP "\f(CWEV_A\fR, \f(CWEV_A_\fR" 4 |
|
|
2272 | .IX Item "EV_A, EV_A_" |
|
|
2273 | This provides the loop \fIargument\fR for functions, if one is required (\*(L"ev |
|
|
2274 | loop argument\*(R"). The \f(CW\*(C`EV_A\*(C'\fR form is used when this is the sole argument, |
|
|
2275 | \&\f(CW\*(C`EV_A_\*(C'\fR is used when other arguments are following. Example: |
|
|
2276 | .Sp |
|
|
2277 | .Vb 3 |
|
|
2278 | \& ev_unref (EV_A); |
|
|
2279 | \& ev_timer_add (EV_A_ watcher); |
|
|
2280 | \& ev_loop (EV_A_ 0); |
|
|
2281 | .Ve |
|
|
2282 | .Sp |
|
|
2283 | It assumes the variable \f(CW\*(C`loop\*(C'\fR of type \f(CW\*(C`struct ev_loop *\*(C'\fR is in scope, |
|
|
2284 | which is often provided by the following macro. |
|
|
2285 | .ie n .IP """EV_P""\fR, \f(CW""EV_P_""" 4 |
|
|
2286 | .el .IP "\f(CWEV_P\fR, \f(CWEV_P_\fR" 4 |
|
|
2287 | .IX Item "EV_P, EV_P_" |
|
|
2288 | This provides the loop \fIparameter\fR for functions, if one is required (\*(L"ev |
|
|
2289 | loop parameter\*(R"). The \f(CW\*(C`EV_P\*(C'\fR form is used when this is the sole parameter, |
|
|
2290 | \&\f(CW\*(C`EV_P_\*(C'\fR is used when other parameters are following. Example: |
|
|
2291 | .Sp |
|
|
2292 | .Vb 2 |
|
|
2293 | \& // this is how ev_unref is being declared |
|
|
2294 | \& static void ev_unref (EV_P); |
|
|
2295 | .Ve |
|
|
2296 | .Sp |
|
|
2297 | .Vb 2 |
|
|
2298 | \& // this is how you can declare your typical callback |
|
|
2299 | \& static void cb (EV_P_ ev_timer *w, int revents) |
|
|
2300 | .Ve |
|
|
2301 | .Sp |
|
|
2302 | It declares a parameter \f(CW\*(C`loop\*(C'\fR of type \f(CW\*(C`struct ev_loop *\*(C'\fR, quite |
|
|
2303 | suitable for use with \f(CW\*(C`EV_A\*(C'\fR. |
|
|
2304 | .ie n .IP """EV_DEFAULT""\fR, \f(CW""EV_DEFAULT_""" 4 |
|
|
2305 | .el .IP "\f(CWEV_DEFAULT\fR, \f(CWEV_DEFAULT_\fR" 4 |
|
|
2306 | .IX Item "EV_DEFAULT, EV_DEFAULT_" |
|
|
2307 | Similar to the other two macros, this gives you the value of the default |
|
|
2308 | loop, if multiple loops are supported (\*(L"ev loop default\*(R"). |
|
|
2309 | .PP |
|
|
2310 | Example: Declare and initialise a check watcher, utilising the above |
|
|
2311 | macros so it will work regardless of whether multiple loops are supported |
|
|
2312 | or not. |
|
|
2313 | .PP |
|
|
2314 | .Vb 5 |
|
|
2315 | \& static void |
|
|
2316 | \& check_cb (EV_P_ ev_timer *w, int revents) |
|
|
2317 | \& { |
|
|
2318 | \& ev_check_stop (EV_A_ w); |
|
|
2319 | \& } |
|
|
2320 | .Ve |
|
|
2321 | .PP |
|
|
2322 | .Vb 4 |
|
|
2323 | \& ev_check check; |
|
|
2324 | \& ev_check_init (&check, check_cb); |
|
|
2325 | \& ev_check_start (EV_DEFAULT_ &check); |
|
|
2326 | \& ev_loop (EV_DEFAULT_ 0); |
1792 | .Ve |
2327 | .Ve |
1793 | .SH "EMBEDDING" |
2328 | .SH "EMBEDDING" |
1794 | .IX Header "EMBEDDING" |
2329 | .IX Header "EMBEDDING" |
1795 | Libev can (and often is) directly embedded into host |
2330 | Libev can (and often is) directly embedded into host |
1796 | applications. Examples of applications that embed it include the Deliantra |
2331 | applications. Examples of applications that embed it include the Deliantra |
… | |
… | |
1845 | .Vb 1 |
2380 | .Vb 1 |
1846 | \& ev_win32.c required on win32 platforms only |
2381 | \& ev_win32.c required on win32 platforms only |
1847 | .Ve |
2382 | .Ve |
1848 | .PP |
2383 | .PP |
1849 | .Vb 5 |
2384 | .Vb 5 |
1850 | \& ev_select.c only when select backend is enabled (which is by default) |
2385 | \& ev_select.c only when select backend is enabled (which is enabled by default) |
1851 | \& ev_poll.c only when poll backend is enabled (disabled by default) |
2386 | \& ev_poll.c only when poll backend is enabled (disabled by default) |
1852 | \& ev_epoll.c only when the epoll backend is enabled (disabled by default) |
2387 | \& ev_epoll.c only when the epoll backend is enabled (disabled by default) |
1853 | \& ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
2388 | \& ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
1854 | \& ev_port.c only when the solaris port backend is enabled (disabled by default) |
2389 | \& ev_port.c only when the solaris port backend is enabled (disabled by default) |
1855 | .Ve |
2390 | .Ve |
… | |
… | |
1976 | otherwise another method will be used as fallback. This is the preferred |
2511 | otherwise another method will be used as fallback. This is the preferred |
1977 | backend for Solaris 10 systems. |
2512 | backend for Solaris 10 systems. |
1978 | .IP "\s-1EV_USE_DEVPOLL\s0" 4 |
2513 | .IP "\s-1EV_USE_DEVPOLL\s0" 4 |
1979 | .IX Item "EV_USE_DEVPOLL" |
2514 | .IX Item "EV_USE_DEVPOLL" |
1980 | reserved for future expansion, works like the \s-1USE\s0 symbols above. |
2515 | reserved for future expansion, works like the \s-1USE\s0 symbols above. |
|
|
2516 | .IP "\s-1EV_USE_INOTIFY\s0" 4 |
|
|
2517 | .IX Item "EV_USE_INOTIFY" |
|
|
2518 | If defined to be \f(CW1\fR, libev will compile in support for the Linux inotify |
|
|
2519 | interface to speed up \f(CW\*(C`ev_stat\*(C'\fR watchers. Its actual availability will |
|
|
2520 | be detected at runtime. |
1981 | .IP "\s-1EV_H\s0" 4 |
2521 | .IP "\s-1EV_H\s0" 4 |
1982 | .IX Item "EV_H" |
2522 | .IX Item "EV_H" |
1983 | The name of the \fIev.h\fR header file used to include it. The default if |
2523 | The name of the \fIev.h\fR header file used to include it. The default if |
1984 | undefined is \f(CW\*(C`<ev.h>\*(C'\fR in \fIevent.h\fR and \f(CW"ev.h"\fR in \fIev.c\fR. This |
2524 | undefined is \f(CW\*(C`<ev.h>\*(C'\fR in \fIevent.h\fR and \f(CW"ev.h"\fR in \fIev.c\fR. This |
1985 | can be used to virtually rename the \fIev.h\fR header file in case of conflicts. |
2525 | can be used to virtually rename the \fIev.h\fR header file in case of conflicts. |
… | |
… | |
2003 | If undefined or defined to \f(CW1\fR, then all event-loop-specific functions |
2543 | If undefined or defined to \f(CW1\fR, then all event-loop-specific functions |
2004 | will have the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument, and you can create |
2544 | will have the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument, and you can create |
2005 | additional independent event loops. Otherwise there will be no support |
2545 | additional independent event loops. Otherwise there will be no support |
2006 | for multiple event loops and there is no first event loop pointer |
2546 | for multiple event loops and there is no first event loop pointer |
2007 | argument. Instead, all functions act on the single default loop. |
2547 | argument. Instead, all functions act on the single default loop. |
|
|
2548 | .IP "\s-1EV_MINPRI\s0" 4 |
|
|
2549 | .IX Item "EV_MINPRI" |
|
|
2550 | .PD 0 |
|
|
2551 | .IP "\s-1EV_MAXPRI\s0" 4 |
|
|
2552 | .IX Item "EV_MAXPRI" |
|
|
2553 | .PD |
|
|
2554 | The range of allowed priorities. \f(CW\*(C`EV_MINPRI\*(C'\fR must be smaller or equal to |
|
|
2555 | \&\f(CW\*(C`EV_MAXPRI\*(C'\fR, but otherwise there are no non-obvious limitations. You can |
|
|
2556 | provide for more priorities by overriding those symbols (usually defined |
|
|
2557 | to be \f(CW\*(C`\-2\*(C'\fR and \f(CW2\fR, respectively). |
|
|
2558 | .Sp |
|
|
2559 | When doing priority-based operations, libev usually has to linearly search |
|
|
2560 | all the priorities, so having many of them (hundreds) uses a lot of space |
|
|
2561 | and time, so using the defaults of five priorities (\-2 .. +2) is usually |
|
|
2562 | fine. |
|
|
2563 | .Sp |
|
|
2564 | If your embedding app does not need any priorities, defining these both to |
|
|
2565 | \&\f(CW0\fR will save some memory and cpu. |
2008 | .IP "\s-1EV_PERIODIC_ENABLE\s0" 4 |
2566 | .IP "\s-1EV_PERIODIC_ENABLE\s0" 4 |
2009 | .IX Item "EV_PERIODIC_ENABLE" |
2567 | .IX Item "EV_PERIODIC_ENABLE" |
2010 | If undefined or defined to be \f(CW1\fR, then periodic timers are supported. If |
2568 | If undefined or defined to be \f(CW1\fR, then periodic timers are supported. If |
|
|
2569 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
|
|
2570 | code. |
|
|
2571 | .IP "\s-1EV_IDLE_ENABLE\s0" 4 |
|
|
2572 | .IX Item "EV_IDLE_ENABLE" |
|
|
2573 | If undefined or defined to be \f(CW1\fR, then idle watchers are supported. If |
2011 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
2574 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
2012 | code. |
2575 | code. |
2013 | .IP "\s-1EV_EMBED_ENABLE\s0" 4 |
2576 | .IP "\s-1EV_EMBED_ENABLE\s0" 4 |
2014 | .IX Item "EV_EMBED_ENABLE" |
2577 | .IX Item "EV_EMBED_ENABLE" |
2015 | If undefined or defined to be \f(CW1\fR, then embed watchers are supported. If |
2578 | If undefined or defined to be \f(CW1\fR, then embed watchers are supported. If |
2016 | defined to be \f(CW0\fR, then they are not. |
2579 | defined to be \f(CW0\fR, then they are not. |
2017 | .IP "\s-1EV_STAT_ENABLE\s0" 4 |
2580 | .IP "\s-1EV_STAT_ENABLE\s0" 4 |
2018 | .IX Item "EV_STAT_ENABLE" |
2581 | .IX Item "EV_STAT_ENABLE" |
2019 | If undefined or defined to be \f(CW1\fR, then stat watchers are supported. If |
2582 | If undefined or defined to be \f(CW1\fR, then stat watchers are supported. If |
2020 | defined to be \f(CW0\fR, then they are not. |
2583 | defined to be \f(CW0\fR, then they are not. |
|
|
2584 | .IP "\s-1EV_FORK_ENABLE\s0" 4 |
|
|
2585 | .IX Item "EV_FORK_ENABLE" |
|
|
2586 | If undefined or defined to be \f(CW1\fR, then fork watchers are supported. If |
|
|
2587 | defined to be \f(CW0\fR, then they are not. |
2021 | .IP "\s-1EV_MINIMAL\s0" 4 |
2588 | .IP "\s-1EV_MINIMAL\s0" 4 |
2022 | .IX Item "EV_MINIMAL" |
2589 | .IX Item "EV_MINIMAL" |
2023 | If you need to shave off some kilobytes of code at the expense of some |
2590 | If you need to shave off some kilobytes of code at the expense of some |
2024 | speed, define this symbol to \f(CW1\fR. Currently only used for gcc to override |
2591 | speed, define this symbol to \f(CW1\fR. Currently only used for gcc to override |
2025 | some inlining decisions, saves roughly 30% codesize of amd64. |
2592 | some inlining decisions, saves roughly 30% codesize of amd64. |
|
|
2593 | .IP "\s-1EV_PID_HASHSIZE\s0" 4 |
|
|
2594 | .IX Item "EV_PID_HASHSIZE" |
|
|
2595 | \&\f(CW\*(C`ev_child\*(C'\fR watchers use a small hash table to distribute workload by |
|
|
2596 | pid. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), usually more |
|
|
2597 | than enough. If you need to manage thousands of children you might want to |
|
|
2598 | increase this value (\fImust\fR be a power of two). |
|
|
2599 | .IP "\s-1EV_INOTIFY_HASHSIZE\s0" 4 |
|
|
2600 | .IX Item "EV_INOTIFY_HASHSIZE" |
|
|
2601 | \&\f(CW\*(C`ev_staz\*(C'\fR watchers use a small hash table to distribute workload by |
|
|
2602 | inotify watch id. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), |
|
|
2603 | usually more than enough. If you need to manage thousands of \f(CW\*(C`ev_stat\*(C'\fR |
|
|
2604 | watchers you might want to increase this value (\fImust\fR be a power of |
|
|
2605 | two). |
2026 | .IP "\s-1EV_COMMON\s0" 4 |
2606 | .IP "\s-1EV_COMMON\s0" 4 |
2027 | .IX Item "EV_COMMON" |
2607 | .IX Item "EV_COMMON" |
2028 | By default, all watchers have a \f(CW\*(C`void *data\*(C'\fR member. By redefining |
2608 | By default, all watchers have a \f(CW\*(C`void *data\*(C'\fR member. By redefining |
2029 | this macro to a something else you can include more and other types of |
2609 | this macro to a something else you can include more and other types of |
2030 | members. You have to define it each time you include one of the files, |
2610 | members. You have to define it each time you include one of the files, |
… | |
… | |
2049 | and the way callbacks are invoked and set. Must expand to a struct member |
2629 | and the way callbacks are invoked and set. Must expand to a struct member |
2050 | definition and a statement, respectively. See the \fIev.v\fR header file for |
2630 | definition and a statement, respectively. See the \fIev.v\fR header file for |
2051 | their default definitions. One possible use for overriding these is to |
2631 | their default definitions. One possible use for overriding these is to |
2052 | avoid the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument in all cases, or to use |
2632 | avoid the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument in all cases, or to use |
2053 | method calls instead of plain function calls in \*(C+. |
2633 | method calls instead of plain function calls in \*(C+. |
|
|
2634 | .Sh "\s-1EXPORTED\s0 \s-1API\s0 \s-1SYMBOLS\s0" |
|
|
2635 | .IX Subsection "EXPORTED API SYMBOLS" |
|
|
2636 | If you need to re-export the \s-1API\s0 (e.g. via a dll) and you need a list of |
|
|
2637 | exported symbols, you can use the provided \fISymbol.*\fR files which list |
|
|
2638 | all public symbols, one per line: |
|
|
2639 | .Sp |
|
|
2640 | .Vb 2 |
|
|
2641 | \& Symbols.ev for libev proper |
|
|
2642 | \& Symbols.event for the libevent emulation |
|
|
2643 | .Ve |
|
|
2644 | .Sp |
|
|
2645 | This can also be used to rename all public symbols to avoid clashes with |
|
|
2646 | multiple versions of libev linked together (which is obviously bad in |
|
|
2647 | itself, but sometimes it is inconvinient to avoid this). |
|
|
2648 | .Sp |
|
|
2649 | A sed comamnd like this will create wrapper \f(CW\*(C`#define\*(C'\fR's that you need to |
|
|
2650 | include before including \fIev.h\fR: |
|
|
2651 | .Sp |
|
|
2652 | .Vb 1 |
|
|
2653 | \& <Symbols.ev sed -e "s/.*/#define & myprefix_&/" >wrap.h |
|
|
2654 | .Ve |
|
|
2655 | .Sp |
|
|
2656 | This would create a file \fIwrap.h\fR which essentially looks like this: |
|
|
2657 | .Sp |
|
|
2658 | .Vb 4 |
|
|
2659 | \& #define ev_backend myprefix_ev_backend |
|
|
2660 | \& #define ev_check_start myprefix_ev_check_start |
|
|
2661 | \& #define ev_check_stop myprefix_ev_check_stop |
|
|
2662 | \& ... |
|
|
2663 | .Ve |
2054 | .Sh "\s-1EXAMPLES\s0" |
2664 | .Sh "\s-1EXAMPLES\s0" |
2055 | .IX Subsection "EXAMPLES" |
2665 | .IX Subsection "EXAMPLES" |
2056 | For a real-world example of a program the includes libev |
2666 | For a real-world example of a program the includes libev |
2057 | verbatim, you can have a look at the \s-1EV\s0 perl module |
2667 | verbatim, you can have a look at the \s-1EV\s0 perl module |
2058 | (<http://software.schmorp.de/pkg/EV.html>). It has the libev files in |
2668 | (<http://software.schmorp.de/pkg/EV.html>). It has the libev files in |
… | |
… | |
2060 | interface) and \fI\s-1EV\s0.xs\fR (implementation) files. Only the \fI\s-1EV\s0.xs\fR file |
2670 | interface) and \fI\s-1EV\s0.xs\fR (implementation) files. Only the \fI\s-1EV\s0.xs\fR file |
2061 | will be compiled. It is pretty complex because it provides its own header |
2671 | will be compiled. It is pretty complex because it provides its own header |
2062 | file. |
2672 | file. |
2063 | .Sp |
2673 | .Sp |
2064 | The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file |
2674 | The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file |
2065 | that everybody includes and which overrides some autoconf choices: |
2675 | that everybody includes and which overrides some configure choices: |
2066 | .Sp |
2676 | .Sp |
2067 | .Vb 4 |
2677 | .Vb 9 |
|
|
2678 | \& #define EV_MINIMAL 1 |
2068 | \& #define EV_USE_POLL 0 |
2679 | \& #define EV_USE_POLL 0 |
2069 | \& #define EV_MULTIPLICITY 0 |
2680 | \& #define EV_MULTIPLICITY 0 |
2070 | \& #define EV_PERIODICS 0 |
2681 | \& #define EV_PERIODIC_ENABLE 0 |
|
|
2682 | \& #define EV_STAT_ENABLE 0 |
|
|
2683 | \& #define EV_FORK_ENABLE 0 |
2071 | \& #define EV_CONFIG_H <config.h> |
2684 | \& #define EV_CONFIG_H <config.h> |
|
|
2685 | \& #define EV_MINPRI 0 |
|
|
2686 | \& #define EV_MAXPRI 0 |
2072 | .Ve |
2687 | .Ve |
2073 | .Sp |
2688 | .Sp |
2074 | .Vb 1 |
2689 | .Vb 1 |
2075 | \& #include "ev++.h" |
2690 | \& #include "ev++.h" |
2076 | .Ve |
2691 | .Ve |
… | |
… | |
2084 | .SH "COMPLEXITIES" |
2699 | .SH "COMPLEXITIES" |
2085 | .IX Header "COMPLEXITIES" |
2700 | .IX Header "COMPLEXITIES" |
2086 | In this section the complexities of (many of) the algorithms used inside |
2701 | In this section the complexities of (many of) the algorithms used inside |
2087 | libev will be explained. For complexity discussions about backends see the |
2702 | libev will be explained. For complexity discussions about backends see the |
2088 | documentation for \f(CW\*(C`ev_default_init\*(C'\fR. |
2703 | documentation for \f(CW\*(C`ev_default_init\*(C'\fR. |
|
|
2704 | .Sp |
|
|
2705 | All of the following are about amortised time: If an array needs to be |
|
|
2706 | extended, libev needs to realloc and move the whole array, but this |
|
|
2707 | happens asymptotically never with higher number of elements, so O(1) might |
|
|
2708 | mean it might do a lengthy realloc operation in rare cases, but on average |
|
|
2709 | it is much faster and asymptotically approaches constant time. |
2089 | .RS 4 |
2710 | .RS 4 |
2090 | .IP "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" 4 |
2711 | .IP "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" 4 |
2091 | .IX Item "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" |
2712 | .IX Item "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" |
2092 | .PD 0 |
2713 | This means that, when you have a watcher that triggers in one hour and |
|
|
2714 | there are 100 watchers that would trigger before that then inserting will |
|
|
2715 | have to skip those 100 watchers. |
2093 | .IP "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" 4 |
2716 | .IP "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" 4 |
2094 | .IX Item "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" |
2717 | .IX Item "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" |
|
|
2718 | That means that for changing a timer costs less than removing/adding them |
|
|
2719 | as only the relative motion in the event queue has to be paid for. |
2095 | .IP "Starting io/check/prepare/idle/signal/child watchers: O(1)" 4 |
2720 | .IP "Starting io/check/prepare/idle/signal/child watchers: O(1)" 4 |
2096 | .IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)" |
2721 | .IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)" |
2097 | .IP "Stopping check/prepare/idle watchers: O(1)" 4 |
2722 | These just add the watcher into an array or at the head of a list. |
2098 | .IX Item "Stopping check/prepare/idle watchers: O(1)" |
2723 | =item Stopping check/prepare/idle watchers: O(1) |
2099 | .IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % 16))" 4 |
2724 | .IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % \s-1EV_PID_HASHSIZE\s0))" 4 |
2100 | .IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % 16))" |
2725 | .IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))" |
|
|
2726 | These watchers are stored in lists then need to be walked to find the |
|
|
2727 | correct watcher to remove. The lists are usually short (you don't usually |
|
|
2728 | have many watchers waiting for the same fd or signal). |
2101 | .IP "Finding the next timer per loop iteration: O(1)" 4 |
2729 | .IP "Finding the next timer per loop iteration: O(1)" 4 |
2102 | .IX Item "Finding the next timer per loop iteration: O(1)" |
2730 | .IX Item "Finding the next timer per loop iteration: O(1)" |
|
|
2731 | .PD 0 |
2103 | .IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4 |
2732 | .IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4 |
2104 | .IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" |
2733 | .IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" |
|
|
2734 | .PD |
|
|
2735 | A change means an I/O watcher gets started or stopped, which requires |
|
|
2736 | libev to recalculate its status (and possibly tell the kernel). |
2105 | .IP "Activating one watcher: O(1)" 4 |
2737 | .IP "Activating one watcher: O(1)" 4 |
2106 | .IX Item "Activating one watcher: O(1)" |
2738 | .IX Item "Activating one watcher: O(1)" |
|
|
2739 | .PD 0 |
|
|
2740 | .IP "Priority handling: O(number_of_priorities)" 4 |
|
|
2741 | .IX Item "Priority handling: O(number_of_priorities)" |
|
|
2742 | .PD |
|
|
2743 | Priorities are implemented by allocating some space for each |
|
|
2744 | priority. When doing priority-based operations, libev usually has to |
|
|
2745 | linearly search all the priorities. |
2107 | .RE |
2746 | .RE |
2108 | .RS 4 |
2747 | .RS 4 |
2109 | .PD |
|
|
2110 | .SH "AUTHOR" |
2748 | .SH "AUTHOR" |
2111 | .IX Header "AUTHOR" |
2749 | .IX Header "AUTHOR" |
2112 | Marc Lehmann <libev@schmorp.de>. |
2750 | Marc Lehmann <libev@schmorp.de>. |