… | |
… | |
127 | .\} |
127 | .\} |
128 | .rm #[ #] #H #V #F C |
128 | .rm #[ #] #H #V #F C |
129 | .\" ======================================================================== |
129 | .\" ======================================================================== |
130 | .\" |
130 | .\" |
131 | .IX Title ""<STANDARD INPUT>" 1" |
131 | .IX Title ""<STANDARD INPUT>" 1" |
132 | .TH "<STANDARD INPUT>" 1 "2007-11-27" "perl v5.8.8" "User Contributed Perl Documentation" |
132 | .TH "<STANDARD INPUT>" 1 "2007-12-07" "perl v5.8.8" "User Contributed Perl Documentation" |
133 | .SH "NAME" |
133 | .SH "NAME" |
134 | libev \- a high performance full\-featured event loop written in C |
134 | libev \- a high performance full\-featured event loop written in C |
135 | .SH "SYNOPSIS" |
135 | .SH "SYNOPSIS" |
136 | .IX Header "SYNOPSIS" |
136 | .IX Header "SYNOPSIS" |
137 | .Vb 1 |
137 | .Vb 1 |
138 | \& #include <ev.h> |
138 | \& #include <ev.h> |
139 | .Ve |
139 | .Ve |
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140 | .SH "EXAMPLE PROGRAM" |
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141 | .IX Header "EXAMPLE PROGRAM" |
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142 | .Vb 1 |
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143 | \& #include <ev.h> |
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144 | .Ve |
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145 | .PP |
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146 | .Vb 2 |
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147 | \& ev_io stdin_watcher; |
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148 | \& ev_timer timeout_watcher; |
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149 | .Ve |
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150 | .PP |
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151 | .Vb 8 |
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152 | \& /* called when data readable on stdin */ |
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153 | \& static void |
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154 | \& stdin_cb (EV_P_ struct ev_io *w, int revents) |
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155 | \& { |
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156 | \& /* puts ("stdin ready"); */ |
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157 | \& ev_io_stop (EV_A_ w); /* just a syntax example */ |
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158 | \& ev_unloop (EV_A_ EVUNLOOP_ALL); /* leave all loop calls */ |
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159 | \& } |
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160 | .Ve |
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161 | .PP |
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162 | .Vb 6 |
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163 | \& static void |
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164 | \& timeout_cb (EV_P_ struct ev_timer *w, int revents) |
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165 | \& { |
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166 | \& /* puts ("timeout"); */ |
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167 | \& ev_unloop (EV_A_ EVUNLOOP_ONE); /* leave one loop call */ |
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168 | \& } |
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169 | .Ve |
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170 | .PP |
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171 | .Vb 4 |
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172 | \& int |
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173 | \& main (void) |
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174 | \& { |
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175 | \& struct ev_loop *loop = ev_default_loop (0); |
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176 | .Ve |
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177 | .PP |
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178 | .Vb 3 |
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179 | \& /* initialise an io watcher, then start it */ |
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180 | \& ev_io_init (&stdin_watcher, stdin_cb, /*STDIN_FILENO*/ 0, EV_READ); |
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181 | \& ev_io_start (loop, &stdin_watcher); |
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182 | .Ve |
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183 | .PP |
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184 | .Vb 3 |
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185 | \& /* simple non-repeating 5.5 second timeout */ |
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186 | \& ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.); |
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187 | \& ev_timer_start (loop, &timeout_watcher); |
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188 | .Ve |
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189 | .PP |
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190 | .Vb 2 |
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191 | \& /* loop till timeout or data ready */ |
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192 | \& ev_loop (loop, 0); |
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193 | .Ve |
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194 | .PP |
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195 | .Vb 2 |
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196 | \& return 0; |
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197 | \& } |
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198 | .Ve |
140 | .SH "DESCRIPTION" |
199 | .SH "DESCRIPTION" |
141 | .IX Header "DESCRIPTION" |
200 | .IX Header "DESCRIPTION" |
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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 |
… | |
… | |
201 | Usually, it's a good idea to terminate if the major versions mismatch, |
270 | Usually, it's a good idea to terminate if the major versions mismatch, |
202 | as this indicates an incompatible change. Minor versions are usually |
271 | as this indicates an incompatible change. Minor versions are usually |
203 | compatible to older versions, so a larger minor version alone is usually |
272 | compatible to older versions, so a larger minor version alone is usually |
204 | not a problem. |
273 | not a problem. |
205 | .Sp |
274 | .Sp |
206 | Example: make sure we haven't accidentally been linked against the wrong |
275 | Example: Make sure we haven't accidentally been linked against the wrong |
207 | version: |
276 | version. |
208 | .Sp |
277 | .Sp |
209 | .Vb 3 |
278 | .Vb 3 |
210 | \& assert (("libev version mismatch", |
279 | \& assert (("libev version mismatch", |
211 | \& ev_version_major () == EV_VERSION_MAJOR |
280 | \& ev_version_major () == EV_VERSION_MAJOR |
212 | \& && ev_version_minor () >= EV_VERSION_MINOR)); |
281 | \& && ev_version_minor () >= EV_VERSION_MINOR)); |
… | |
… | |
242 | recommended ones. |
311 | recommended ones. |
243 | .Sp |
312 | .Sp |
244 | See the description of \f(CW\*(C`ev_embed\*(C'\fR watchers for more info. |
313 | 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 |
314 | .IP "ev_set_allocator (void *(*cb)(void *ptr, long size))" 4 |
246 | .IX Item "ev_set_allocator (void *(*cb)(void *ptr, long size))" |
315 | .IX Item "ev_set_allocator (void *(*cb)(void *ptr, long size))" |
247 | Sets the allocation function to use (the prototype is similar to the |
316 | Sets the allocation function to use (the prototype is similar \- the |
248 | realloc C function, the semantics are identical). It is used to allocate |
317 | 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 |
318 | 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 |
319 | memory needs to be allocated, the library might abort or take some |
251 | destructive action. The default is your system realloc function. |
320 | potentially destructive action. The default is your system realloc |
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321 | function. |
252 | .Sp |
322 | .Sp |
253 | You could override this function in high-availability programs to, say, |
323 | 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, |
324 | 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. |
325 | or even to sleep a while and retry until some memory is available. |
256 | .Sp |
326 | .Sp |
257 | Example: replace the libev allocator with one that waits a bit and then |
327 | Example: Replace the libev allocator with one that waits a bit and then |
258 | retries: better than mine). |
328 | retries). |
259 | .Sp |
329 | .Sp |
260 | .Vb 6 |
330 | .Vb 6 |
261 | \& static void * |
331 | \& static void * |
262 | \& persistent_realloc (void *ptr, long size) |
332 | \& persistent_realloc (void *ptr, size_t size) |
263 | \& { |
333 | \& { |
264 | \& for (;;) |
334 | \& for (;;) |
265 | \& { |
335 | \& { |
266 | \& void *newptr = realloc (ptr, size); |
336 | \& void *newptr = realloc (ptr, size); |
267 | .Ve |
337 | .Ve |
… | |
… | |
289 | callback is set, then libev will expect it to remedy the sitution, no |
359 | 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 |
360 | 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 |
361 | requested operation, or, if the condition doesn't go away, do bad stuff |
292 | (such as abort). |
362 | (such as abort). |
293 | .Sp |
363 | .Sp |
294 | Example: do the same thing as libev does internally: |
364 | Example: This is basically the same thing that libev does internally, too. |
295 | .Sp |
365 | .Sp |
296 | .Vb 6 |
366 | .Vb 6 |
297 | \& static void |
367 | \& static void |
298 | \& fatal_error (const char *msg) |
368 | \& fatal_error (const char *msg) |
299 | \& { |
369 | \& { |
… | |
… | |
345 | or setgid) then libev will \fInot\fR look at the environment variable |
415 | 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 |
416 | \&\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 |
417 | 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 |
418 | useful to try out specific backends to test their performance, or to work |
349 | around bugs. |
419 | around bugs. |
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420 | .ie n .IP """EVFLAG_FORKCHECK""" 4 |
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421 | .el .IP "\f(CWEVFLAG_FORKCHECK\fR" 4 |
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422 | .IX Item "EVFLAG_FORKCHECK" |
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423 | 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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424 | a fork, you can also make libev check for a fork in each iteration by |
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425 | enabling this flag. |
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426 | .Sp |
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427 | This works by calling \f(CW\*(C`getpid ()\*(C'\fR on every iteration of the loop, |
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428 | and thus this might slow down your event loop if you do a lot of loop |
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429 | iterations and little real work, but is usually not noticeable (on my |
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430 | Linux system for example, \f(CW\*(C`getpid\*(C'\fR is actually a simple 5\-insn sequence |
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431 | without a syscall and thus \fIvery\fR fast, but my Linux system also has |
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432 | \&\f(CW\*(C`pthread_atfork\*(C'\fR which is even faster). |
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433 | .Sp |
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434 | The big advantage of this flag is that you can forget about fork (and |
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435 | forget about forgetting to tell libev about forking) when you use this |
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436 | flag. |
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437 | .Sp |
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438 | This flag setting cannot be overriden or specified in the \f(CW\*(C`LIBEV_FLAGS\*(C'\fR |
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439 | environment variable. |
350 | .ie n .IP """EVBACKEND_SELECT"" (value 1, portable select backend)" 4 |
440 | .ie n .IP """EVBACKEND_SELECT"" (value 1, portable select backend)" 4 |
351 | .el .IP "\f(CWEVBACKEND_SELECT\fR (value 1, portable select backend)" 4 |
441 | .el .IP "\f(CWEVBACKEND_SELECT\fR (value 1, portable select backend)" 4 |
352 | .IX Item "EVBACKEND_SELECT (value 1, portable select backend)" |
442 | .IX Item "EVBACKEND_SELECT (value 1, portable select backend)" |
353 | This is your standard \fIselect\fR\|(2) backend. Not \fIcompletely\fR standard, as |
443 | 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, |
444 | 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 |
538 | 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 |
539 | 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 |
540 | 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). |
541 | undefined behaviour (or a failed assertion if assertions are enabled). |
452 | .Sp |
542 | .Sp |
453 | Example: try to create a event loop that uses epoll and nothing else. |
543 | Example: Try to create a event loop that uses epoll and nothing else. |
454 | .Sp |
544 | .Sp |
455 | .Vb 3 |
545 | .Vb 3 |
456 | \& struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
546 | \& struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
457 | \& if (!epoller) |
547 | \& if (!epoller) |
458 | \& fatal ("no epoll found here, maybe it hides under your chair"); |
548 | \& fatal ("no epoll found here, maybe it hides under your chair"); |
… | |
… | |
495 | .IP "ev_loop_fork (loop)" 4 |
585 | .IP "ev_loop_fork (loop)" 4 |
496 | .IX Item "ev_loop_fork (loop)" |
586 | .IX Item "ev_loop_fork (loop)" |
497 | Like \f(CW\*(C`ev_default_fork\*(C'\fR, but acts on an event loop created by |
587 | 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 |
588 | \&\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. |
589 | after fork, and how you do this is entirely your own problem. |
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590 | .IP "unsigned int ev_loop_count (loop)" 4 |
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591 | .IX Item "unsigned int ev_loop_count (loop)" |
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592 | Returns the count of loop iterations for the loop, which is identical to |
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593 | the number of times libev did poll for new events. It starts at \f(CW0\fR and |
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594 | happily wraps around with enough iterations. |
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595 | .Sp |
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596 | This value can sometimes be useful as a generation counter of sorts (it |
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597 | \&\*(L"ticks\*(R" the number of loop iterations), as it roughly corresponds with |
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598 | \&\f(CW\*(C`ev_prepare\*(C'\fR and \f(CW\*(C`ev_check\*(C'\fR calls. |
500 | .IP "unsigned int ev_backend (loop)" 4 |
599 | .IP "unsigned int ev_backend (loop)" 4 |
501 | .IX Item "unsigned int ev_backend (loop)" |
600 | .IX Item "unsigned int ev_backend (loop)" |
502 | Returns one of the \f(CW\*(C`EVBACKEND_*\*(C'\fR flags indicating the event backend in |
601 | Returns one of the \f(CW\*(C`EVBACKEND_*\*(C'\fR flags indicating the event backend in |
503 | use. |
602 | use. |
504 | .IP "ev_tstamp ev_now (loop)" 4 |
603 | .IP "ev_tstamp ev_now (loop)" 4 |
… | |
… | |
556 | \& be handled here by queueing them when their watcher gets executed. |
655 | \& be handled here by queueing them when their watcher gets executed. |
557 | \& - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
656 | \& - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
558 | \& were used, return, otherwise continue with step *. |
657 | \& were used, return, otherwise continue with step *. |
559 | .Ve |
658 | .Ve |
560 | .Sp |
659 | .Sp |
561 | Example: queue some jobs and then loop until no events are outsanding |
660 | Example: Queue some jobs and then loop until no events are outsanding |
562 | anymore. |
661 | anymore. |
563 | .Sp |
662 | .Sp |
564 | .Vb 4 |
663 | .Vb 4 |
565 | \& ... queue jobs here, make sure they register event watchers as long |
664 | \& ... 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..) |
665 | \& ... 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 |
687 | 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 |
688 | 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 |
689 | 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. |
690 | libraries. Just remember to \fIunref after start\fR and \fIref before stop\fR. |
592 | .Sp |
691 | .Sp |
593 | Example: create a signal watcher, but keep it from keeping \f(CW\*(C`ev_loop\*(C'\fR |
692 | Example: Create a signal watcher, but keep it from keeping \f(CW\*(C`ev_loop\*(C'\fR |
594 | running when nothing else is active. |
693 | running when nothing else is active. |
595 | .Sp |
694 | .Sp |
596 | .Vb 4 |
695 | .Vb 4 |
597 | \& struct dv_signal exitsig; |
696 | \& struct ev_signal exitsig; |
598 | \& ev_signal_init (&exitsig, sig_cb, SIGINT); |
697 | \& ev_signal_init (&exitsig, sig_cb, SIGINT); |
599 | \& ev_signal_start (myloop, &exitsig); |
698 | \& ev_signal_start (loop, &exitsig); |
600 | \& evf_unref (myloop); |
699 | \& evf_unref (loop); |
601 | .Ve |
700 | .Ve |
602 | .Sp |
701 | .Sp |
603 | Example: for some weird reason, unregister the above signal handler again. |
702 | Example: For some weird reason, unregister the above signal handler again. |
604 | .Sp |
703 | .Sp |
605 | .Vb 2 |
704 | .Vb 2 |
606 | \& ev_ref (myloop); |
705 | \& ev_ref (loop); |
607 | \& ev_signal_stop (myloop, &exitsig); |
706 | \& ev_signal_stop (loop, &exitsig); |
608 | .Ve |
707 | .Ve |
609 | .SH "ANATOMY OF A WATCHER" |
708 | .SH "ANATOMY OF A WATCHER" |
610 | .IX Header "ANATOMY OF A WATCHER" |
709 | .IX Header "ANATOMY OF A WATCHER" |
611 | A watcher is a structure that you create and register to record your |
710 | 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 |
711 | interest in some event. For instance, if you want to wait for \s-1STDIN\s0 to |
… | |
… | |
792 | Returns a true value iff the watcher is pending, (i.e. it has outstanding |
891 | Returns a true value iff the watcher is pending, (i.e. it has outstanding |
793 | events but its callback has not yet been invoked). As long as a watcher |
892 | events but its callback has not yet been invoked). As long as a watcher |
794 | is pending (but not active) you must not call an init function on it (but |
893 | is pending (but not active) you must not call an init function on it (but |
795 | \&\f(CW\*(C`ev_TYPE_set\*(C'\fR is safe) and you must make sure the watcher is available to |
894 | \&\f(CW\*(C`ev_TYPE_set\*(C'\fR is safe) and you must make sure the watcher is available to |
796 | libev (e.g. you cnanot \f(CW\*(C`free ()\*(C'\fR it). |
895 | libev (e.g. you cnanot \f(CW\*(C`free ()\*(C'\fR it). |
797 | .IP "callback = ev_cb (ev_TYPE *watcher)" 4 |
896 | .IP "callback ev_cb (ev_TYPE *watcher)" 4 |
798 | .IX Item "callback = ev_cb (ev_TYPE *watcher)" |
897 | .IX Item "callback ev_cb (ev_TYPE *watcher)" |
799 | Returns the callback currently set on the watcher. |
898 | Returns the callback currently set on the watcher. |
800 | .IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 |
899 | .IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 |
801 | .IX Item "ev_cb_set (ev_TYPE *watcher, callback)" |
900 | .IX Item "ev_cb_set (ev_TYPE *watcher, callback)" |
802 | Change the callback. You can change the callback at virtually any time |
901 | Change the callback. You can change the callback at virtually any time |
803 | (modulo threads). |
902 | (modulo threads). |
|
|
903 | .IP "ev_set_priority (ev_TYPE *watcher, priority)" 4 |
|
|
904 | .IX Item "ev_set_priority (ev_TYPE *watcher, priority)" |
|
|
905 | .PD 0 |
|
|
906 | .IP "int ev_priority (ev_TYPE *watcher)" 4 |
|
|
907 | .IX Item "int ev_priority (ev_TYPE *watcher)" |
|
|
908 | .PD |
|
|
909 | Set and query the priority of the watcher. The priority is a small |
|
|
910 | integer between \f(CW\*(C`EV_MAXPRI\*(C'\fR (default: \f(CW2\fR) and \f(CW\*(C`EV_MINPRI\*(C'\fR |
|
|
911 | (default: \f(CW\*(C`\-2\*(C'\fR). Pending watchers with higher priority will be invoked |
|
|
912 | before watchers with lower priority, but priority will not keep watchers |
|
|
913 | from being executed (except for \f(CW\*(C`ev_idle\*(C'\fR watchers). |
|
|
914 | .Sp |
|
|
915 | This means that priorities are \fIonly\fR used for ordering callback |
|
|
916 | invocation after new events have been received. This is useful, for |
|
|
917 | example, to reduce latency after idling, or more often, to bind two |
|
|
918 | watchers on the same event and make sure one is called first. |
|
|
919 | .Sp |
|
|
920 | If you need to suppress invocation when higher priority events are pending |
|
|
921 | you need to look at \f(CW\*(C`ev_idle\*(C'\fR watchers, which provide this functionality. |
|
|
922 | .Sp |
|
|
923 | The default priority used by watchers when no priority has been set is |
|
|
924 | always \f(CW0\fR, which is supposed to not be too high and not be too low :). |
|
|
925 | .Sp |
|
|
926 | Setting a priority outside the range of \f(CW\*(C`EV_MINPRI\*(C'\fR to \f(CW\*(C`EV_MAXPRI\*(C'\fR is |
|
|
927 | fine, as long as you do not mind that the priority value you query might |
|
|
928 | or might not have been adjusted to be within valid range. |
804 | .Sh "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0" |
929 | .Sh "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0" |
805 | .IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER" |
930 | .IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER" |
806 | Each watcher has, by default, a member \f(CW\*(C`void *data\*(C'\fR that you can change |
931 | Each watcher has, by default, a member \f(CW\*(C`void *data\*(C'\fR that you can change |
807 | and read at any time, libev will completely ignore it. This can be used |
932 | and read at any time, libev will completely ignore it. This can be used |
808 | to associate arbitrary data with your watcher. If you need more data and |
933 | to associate arbitrary data with your watcher. If you need more data and |
… | |
… | |
829 | \& struct my_io *w = (struct my_io *)w_; |
954 | \& struct my_io *w = (struct my_io *)w_; |
830 | \& ... |
955 | \& ... |
831 | \& } |
956 | \& } |
832 | .Ve |
957 | .Ve |
833 | .PP |
958 | .PP |
834 | More interesting and less C\-conformant ways of catsing your callback type |
959 | More interesting and less C\-conformant ways of casting your callback type |
835 | have been omitted.... |
960 | instead have been omitted. |
|
|
961 | .PP |
|
|
962 | Another common scenario is having some data structure with multiple |
|
|
963 | watchers: |
|
|
964 | .PP |
|
|
965 | .Vb 6 |
|
|
966 | \& struct my_biggy |
|
|
967 | \& { |
|
|
968 | \& int some_data; |
|
|
969 | \& ev_timer t1; |
|
|
970 | \& ev_timer t2; |
|
|
971 | \& } |
|
|
972 | .Ve |
|
|
973 | .PP |
|
|
974 | In this case getting the pointer to \f(CW\*(C`my_biggy\*(C'\fR is a bit more complicated, |
|
|
975 | you need to use \f(CW\*(C`offsetof\*(C'\fR: |
|
|
976 | .PP |
|
|
977 | .Vb 1 |
|
|
978 | \& #include <stddef.h> |
|
|
979 | .Ve |
|
|
980 | .PP |
|
|
981 | .Vb 6 |
|
|
982 | \& static void |
|
|
983 | \& t1_cb (EV_P_ struct ev_timer *w, int revents) |
|
|
984 | \& { |
|
|
985 | \& struct my_biggy big = (struct my_biggy * |
|
|
986 | \& (((char *)w) - offsetof (struct my_biggy, t1)); |
|
|
987 | \& } |
|
|
988 | .Ve |
|
|
989 | .PP |
|
|
990 | .Vb 6 |
|
|
991 | \& static void |
|
|
992 | \& t2_cb (EV_P_ struct ev_timer *w, int revents) |
|
|
993 | \& { |
|
|
994 | \& struct my_biggy big = (struct my_biggy * |
|
|
995 | \& (((char *)w) - offsetof (struct my_biggy, t2)); |
|
|
996 | \& } |
|
|
997 | .Ve |
836 | .SH "WATCHER TYPES" |
998 | .SH "WATCHER TYPES" |
837 | .IX Header "WATCHER TYPES" |
999 | .IX Header "WATCHER TYPES" |
838 | This section describes each watcher in detail, but will not repeat |
1000 | This section describes each watcher in detail, but will not repeat |
839 | information given in the last section. Any initialisation/set macros, |
1001 | information given in the last section. Any initialisation/set macros, |
840 | functions and members specific to the watcher type are explained. |
1002 | functions and members specific to the watcher type are explained. |
… | |
… | |
882 | it is best to always use non-blocking I/O: An extra \f(CW\*(C`read\*(C'\fR(2) returning |
1044 | it is best to always use non-blocking I/O: An extra \f(CW\*(C`read\*(C'\fR(2) returning |
883 | \&\f(CW\*(C`EAGAIN\*(C'\fR is far preferable to a program hanging until some data arrives. |
1045 | \&\f(CW\*(C`EAGAIN\*(C'\fR is far preferable to a program hanging until some data arrives. |
884 | .PP |
1046 | .PP |
885 | If you cannot run the fd in non-blocking mode (for example you should not |
1047 | If you cannot run the fd in non-blocking mode (for example you should not |
886 | play around with an Xlib connection), then you have to seperately re-test |
1048 | play around with an Xlib connection), then you have to seperately re-test |
887 | wether a file descriptor is really ready with a known-to-be good interface |
1049 | whether a file descriptor is really ready with a known-to-be good interface |
888 | such as poll (fortunately in our Xlib example, Xlib already does this on |
1050 | such as poll (fortunately in our Xlib example, Xlib already does this on |
889 | its own, so its quite safe to use). |
1051 | its own, so its quite safe to use). |
890 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
1052 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
891 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
1053 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
892 | .PD 0 |
1054 | .PD 0 |
… | |
… | |
901 | The file descriptor being watched. |
1063 | The file descriptor being watched. |
902 | .IP "int events [read\-only]" 4 |
1064 | .IP "int events [read\-only]" 4 |
903 | .IX Item "int events [read-only]" |
1065 | .IX Item "int events [read-only]" |
904 | The events being watched. |
1066 | The events being watched. |
905 | .PP |
1067 | .PP |
906 | Example: call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well |
1068 | Example: Call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well |
907 | readable, but only once. Since it is likely line\-buffered, you could |
1069 | readable, but only once. Since it is likely line\-buffered, you could |
908 | attempt to read a whole line in the callback: |
1070 | attempt to read a whole line in the callback. |
909 | .PP |
1071 | .PP |
910 | .Vb 6 |
1072 | .Vb 6 |
911 | \& static void |
1073 | \& static void |
912 | \& stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
1074 | \& stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
913 | \& { |
1075 | \& { |
… | |
… | |
968 | .IP "ev_timer_again (loop)" 4 |
1130 | .IP "ev_timer_again (loop)" 4 |
969 | .IX Item "ev_timer_again (loop)" |
1131 | .IX Item "ev_timer_again (loop)" |
970 | This will act as if the timer timed out and restart it again if it is |
1132 | This will act as if the timer timed out and restart it again if it is |
971 | repeating. The exact semantics are: |
1133 | repeating. The exact semantics are: |
972 | .Sp |
1134 | .Sp |
|
|
1135 | If the timer is pending, its pending status is cleared. |
|
|
1136 | .Sp |
973 | If the timer is started but nonrepeating, stop it. |
1137 | If the timer is started but nonrepeating, stop it (as if it timed out). |
974 | .Sp |
1138 | .Sp |
975 | If the timer is repeating, either start it if necessary (with the repeat |
1139 | If the timer is repeating, either start it if necessary (with the |
976 | value), or reset the running timer to the repeat value. |
1140 | \&\f(CW\*(C`repeat\*(C'\fR value), or reset the running timer to the \f(CW\*(C`repeat\*(C'\fR value. |
977 | .Sp |
1141 | .Sp |
978 | This sounds a bit complicated, but here is a useful and typical |
1142 | This sounds a bit complicated, but here is a useful and typical |
979 | example: Imagine you have a tcp connection and you want a so-called |
1143 | example: Imagine you have a tcp connection and you want a so-called idle |
980 | idle timeout, that is, you want to be called when there have been, |
1144 | timeout, that is, you want to be called when there have been, say, 60 |
981 | say, 60 seconds of inactivity on the socket. The easiest way to do |
1145 | seconds of inactivity on the socket. The easiest way to do this is to |
982 | 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 |
1146 | 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 |
983 | \&\f(CW\*(C`ev_timer_again\*(C'\fR each time you successfully read or write some data. If |
1147 | \&\f(CW\*(C`ev_timer_again\*(C'\fR each time you successfully read or write some data. If |
984 | you go into an idle state where you do not expect data to travel on the |
1148 | you go into an idle state where you do not expect data to travel on the |
985 | socket, you can stop the timer, and again will automatically restart it if |
1149 | socket, you can \f(CW\*(C`ev_timer_stop\*(C'\fR the timer, and \f(CW\*(C`ev_timer_again\*(C'\fR will |
986 | need be. |
1150 | automatically restart it if need be. |
987 | .Sp |
1151 | .Sp |
988 | You can also ignore the \f(CW\*(C`after\*(C'\fR value and \f(CW\*(C`ev_timer_start\*(C'\fR altogether |
1152 | That means you can ignore the \f(CW\*(C`after\*(C'\fR value and \f(CW\*(C`ev_timer_start\*(C'\fR |
989 | and only ever use the \f(CW\*(C`repeat\*(C'\fR value: |
1153 | altogether and only ever use the \f(CW\*(C`repeat\*(C'\fR value and \f(CW\*(C`ev_timer_again\*(C'\fR: |
990 | .Sp |
1154 | .Sp |
991 | .Vb 8 |
1155 | .Vb 8 |
992 | \& ev_timer_init (timer, callback, 0., 5.); |
1156 | \& ev_timer_init (timer, callback, 0., 5.); |
993 | \& ev_timer_again (loop, timer); |
1157 | \& ev_timer_again (loop, timer); |
994 | \& ... |
1158 | \& ... |
… | |
… | |
997 | \& ... |
1161 | \& ... |
998 | \& timer->again = 10.; |
1162 | \& timer->again = 10.; |
999 | \& ev_timer_again (loop, timer); |
1163 | \& ev_timer_again (loop, timer); |
1000 | .Ve |
1164 | .Ve |
1001 | .Sp |
1165 | .Sp |
1002 | This is more efficient then stopping/starting the timer eahc time you want |
1166 | This is more slightly efficient then stopping/starting the timer each time |
1003 | to modify its timeout value. |
1167 | you want to modify its timeout value. |
1004 | .IP "ev_tstamp repeat [read\-write]" 4 |
1168 | .IP "ev_tstamp repeat [read\-write]" 4 |
1005 | .IX Item "ev_tstamp repeat [read-write]" |
1169 | .IX Item "ev_tstamp repeat [read-write]" |
1006 | The current \f(CW\*(C`repeat\*(C'\fR value. Will be used each time the watcher times out |
1170 | The current \f(CW\*(C`repeat\*(C'\fR value. Will be used each time the watcher times out |
1007 | or \f(CW\*(C`ev_timer_again\*(C'\fR is called and determines the next timeout (if any), |
1171 | or \f(CW\*(C`ev_timer_again\*(C'\fR is called and determines the next timeout (if any), |
1008 | which is also when any modifications are taken into account. |
1172 | which is also when any modifications are taken into account. |
1009 | .PP |
1173 | .PP |
1010 | Example: create a timer that fires after 60 seconds. |
1174 | Example: Create a timer that fires after 60 seconds. |
1011 | .PP |
1175 | .PP |
1012 | .Vb 5 |
1176 | .Vb 5 |
1013 | \& static void |
1177 | \& static void |
1014 | \& one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1178 | \& one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1015 | \& { |
1179 | \& { |
… | |
… | |
1021 | \& struct ev_timer mytimer; |
1185 | \& struct ev_timer mytimer; |
1022 | \& ev_timer_init (&mytimer, one_minute_cb, 60., 0.); |
1186 | \& ev_timer_init (&mytimer, one_minute_cb, 60., 0.); |
1023 | \& ev_timer_start (loop, &mytimer); |
1187 | \& ev_timer_start (loop, &mytimer); |
1024 | .Ve |
1188 | .Ve |
1025 | .PP |
1189 | .PP |
1026 | Example: create a timeout timer that times out after 10 seconds of |
1190 | Example: Create a timeout timer that times out after 10 seconds of |
1027 | inactivity. |
1191 | inactivity. |
1028 | .PP |
1192 | .PP |
1029 | .Vb 5 |
1193 | .Vb 5 |
1030 | \& static void |
1194 | \& static void |
1031 | \& timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1195 | \& timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
… | |
… | |
1156 | .IX Item "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write]" |
1320 | .IX Item "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write]" |
1157 | The current reschedule callback, or \f(CW0\fR, if this functionality is |
1321 | The current reschedule callback, or \f(CW0\fR, if this functionality is |
1158 | switched off. Can be changed any time, but changes only take effect when |
1322 | switched off. Can be changed any time, but changes only take effect when |
1159 | the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called. |
1323 | the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called. |
1160 | .PP |
1324 | .PP |
1161 | Example: call a callback every hour, or, more precisely, whenever the |
1325 | Example: Call a callback every hour, or, more precisely, whenever the |
1162 | system clock is divisible by 3600. The callback invocation times have |
1326 | system clock is divisible by 3600. The callback invocation times have |
1163 | potentially a lot of jittering, but good long-term stability. |
1327 | potentially a lot of jittering, but good long-term stability. |
1164 | .PP |
1328 | .PP |
1165 | .Vb 5 |
1329 | .Vb 5 |
1166 | \& static void |
1330 | \& static void |
… | |
… | |
1174 | \& struct ev_periodic hourly_tick; |
1338 | \& struct ev_periodic hourly_tick; |
1175 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); |
1339 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); |
1176 | \& ev_periodic_start (loop, &hourly_tick); |
1340 | \& ev_periodic_start (loop, &hourly_tick); |
1177 | .Ve |
1341 | .Ve |
1178 | .PP |
1342 | .PP |
1179 | Example: the same as above, but use a reschedule callback to do it: |
1343 | Example: The same as above, but use a reschedule callback to do it: |
1180 | .PP |
1344 | .PP |
1181 | .Vb 1 |
1345 | .Vb 1 |
1182 | \& #include <math.h> |
1346 | \& #include <math.h> |
1183 | .Ve |
1347 | .Ve |
1184 | .PP |
1348 | .PP |
… | |
… | |
1192 | .PP |
1356 | .PP |
1193 | .Vb 1 |
1357 | .Vb 1 |
1194 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); |
1358 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); |
1195 | .Ve |
1359 | .Ve |
1196 | .PP |
1360 | .PP |
1197 | Example: call a callback every hour, starting now: |
1361 | Example: Call a callback every hour, starting now: |
1198 | .PP |
1362 | .PP |
1199 | .Vb 4 |
1363 | .Vb 4 |
1200 | \& struct ev_periodic hourly_tick; |
1364 | \& struct ev_periodic hourly_tick; |
1201 | \& ev_periodic_init (&hourly_tick, clock_cb, |
1365 | \& ev_periodic_init (&hourly_tick, clock_cb, |
1202 | \& fmod (ev_now (loop), 3600.), 3600., 0); |
1366 | \& fmod (ev_now (loop), 3600.), 3600., 0); |
… | |
… | |
1253 | .IP "int rstatus [read\-write]" 4 |
1417 | .IP "int rstatus [read\-write]" 4 |
1254 | .IX Item "int rstatus [read-write]" |
1418 | .IX Item "int rstatus [read-write]" |
1255 | The process exit/trace status caused by \f(CW\*(C`rpid\*(C'\fR (see your systems |
1419 | The process exit/trace status caused by \f(CW\*(C`rpid\*(C'\fR (see your systems |
1256 | \&\f(CW\*(C`waitpid\*(C'\fR and \f(CW\*(C`sys/wait.h\*(C'\fR documentation for details). |
1420 | \&\f(CW\*(C`waitpid\*(C'\fR and \f(CW\*(C`sys/wait.h\*(C'\fR documentation for details). |
1257 | .PP |
1421 | .PP |
1258 | Example: try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0. |
1422 | Example: Try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0. |
1259 | .PP |
1423 | .PP |
1260 | .Vb 5 |
1424 | .Vb 5 |
1261 | \& static void |
1425 | \& static void |
1262 | \& sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
1426 | \& sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
1263 | \& { |
1427 | \& { |
… | |
… | |
1281 | not exist\*(R" is a status change like any other. The condition \*(L"path does |
1445 | not exist\*(R" is a status change like any other. The condition \*(L"path does |
1282 | not exist\*(R" is signified by the \f(CW\*(C`st_nlink\*(C'\fR field being zero (which is |
1446 | not exist\*(R" is signified by the \f(CW\*(C`st_nlink\*(C'\fR field being zero (which is |
1283 | otherwise always forced to be at least one) and all the other fields of |
1447 | otherwise always forced to be at least one) and all the other fields of |
1284 | the stat buffer having unspecified contents. |
1448 | the stat buffer having unspecified contents. |
1285 | .PP |
1449 | .PP |
|
|
1450 | The path \fIshould\fR be absolute and \fImust not\fR end in a slash. If it is |
|
|
1451 | relative and your working directory changes, the behaviour is undefined. |
|
|
1452 | .PP |
1286 | Since there is no standard to do this, the portable implementation simply |
1453 | Since there is no standard to do this, the portable implementation simply |
1287 | calls \f(CW\*(C`stat (2)\*(C'\fR regulalry on the path to see if it changed somehow. You |
1454 | calls \f(CW\*(C`stat (2)\*(C'\fR regularly on the path to see if it changed somehow. You |
1288 | can specify a recommended polling interval for this case. If you specify |
1455 | can specify a recommended polling interval for this case. If you specify |
1289 | a polling interval of \f(CW0\fR (highly recommended!) then a \fIsuitable, |
1456 | a polling interval of \f(CW0\fR (highly recommended!) then a \fIsuitable, |
1290 | unspecified default\fR value will be used (which you can expect to be around |
1457 | unspecified default\fR value will be used (which you can expect to be around |
1291 | five seconds, although this might change dynamically). Libev will also |
1458 | five seconds, although this might change dynamically). Libev will also |
1292 | impose a minimum interval which is currently around \f(CW0.1\fR, but thats |
1459 | impose a minimum interval which is currently around \f(CW0.1\fR, but thats |
… | |
… | |
1294 | .PP |
1461 | .PP |
1295 | This watcher type is not meant for massive numbers of stat watchers, |
1462 | This watcher type is not meant for massive numbers of stat watchers, |
1296 | as even with OS-supported change notifications, this can be |
1463 | as even with OS-supported change notifications, this can be |
1297 | resource\-intensive. |
1464 | resource\-intensive. |
1298 | .PP |
1465 | .PP |
1299 | At the time of this writing, no specific \s-1OS\s0 backends are implemented, but |
1466 | At the time of this writing, only the Linux inotify interface is |
1300 | if demand increases, at least a kqueue and inotify backend will be added. |
1467 | implemented (implementing kqueue support is left as an exercise for the |
|
|
1468 | reader). Inotify will be used to give hints only and should not change the |
|
|
1469 | semantics of \f(CW\*(C`ev_stat\*(C'\fR watchers, which means that libev sometimes needs |
|
|
1470 | to fall back to regular polling again even with inotify, but changes are |
|
|
1471 | usually detected immediately, and if the file exists there will be no |
|
|
1472 | polling. |
1301 | .IP "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" 4 |
1473 | .IP "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" 4 |
1302 | .IX Item "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" |
1474 | .IX Item "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" |
1303 | .PD 0 |
1475 | .PD 0 |
1304 | .IP "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" 4 |
1476 | .IP "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" 4 |
1305 | .IX Item "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" |
1477 | .IX Item "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" |
… | |
… | |
1366 | \& ev_stat_start (loop, &passwd); |
1538 | \& ev_stat_start (loop, &passwd); |
1367 | .Ve |
1539 | .Ve |
1368 | .ie n .Sh """ev_idle"" \- when you've got nothing better to do..." |
1540 | .ie n .Sh """ev_idle"" \- when you've got nothing better to do..." |
1369 | .el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do..." |
1541 | .el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do..." |
1370 | .IX Subsection "ev_idle - when you've got nothing better to do..." |
1542 | .IX Subsection "ev_idle - when you've got nothing better to do..." |
1371 | Idle watchers trigger events when there are no other events are pending |
1543 | Idle watchers trigger events when no other events of the same or higher |
1372 | (prepare, check and other idle watchers do not count). That is, as long |
1544 | priority are pending (prepare, check and other idle watchers do not |
1373 | as your process is busy handling sockets or timeouts (or even signals, |
1545 | count). |
1374 | imagine) it will not be triggered. But when your process is idle all idle |
1546 | .PP |
1375 | watchers are being called again and again, once per event loop iteration \- |
1547 | That is, as long as your process is busy handling sockets or timeouts |
|
|
1548 | (or even signals, imagine) of the same or higher priority it will not be |
|
|
1549 | triggered. But when your process is idle (or only lower-priority watchers |
|
|
1550 | are pending), the idle watchers are being called once per event loop |
1376 | until stopped, that is, or your process receives more events and becomes |
1551 | iteration \- until stopped, that is, or your process receives more events |
1377 | busy. |
1552 | and becomes busy again with higher priority stuff. |
1378 | .PP |
1553 | .PP |
1379 | The most noteworthy effect is that as long as any idle watchers are |
1554 | The most noteworthy effect is that as long as any idle watchers are |
1380 | active, the process will not block when waiting for new events. |
1555 | active, the process will not block when waiting for new events. |
1381 | .PP |
1556 | .PP |
1382 | Apart from keeping your process non-blocking (which is a useful |
1557 | Apart from keeping your process non-blocking (which is a useful |
… | |
… | |
1387 | .IX Item "ev_idle_init (ev_signal *, callback)" |
1562 | .IX Item "ev_idle_init (ev_signal *, callback)" |
1388 | Initialises and configures the idle watcher \- it has no parameters of any |
1563 | Initialises and configures the idle watcher \- it has no parameters of any |
1389 | kind. There is a \f(CW\*(C`ev_idle_set\*(C'\fR macro, but using it is utterly pointless, |
1564 | kind. There is a \f(CW\*(C`ev_idle_set\*(C'\fR macro, but using it is utterly pointless, |
1390 | believe me. |
1565 | believe me. |
1391 | .PP |
1566 | .PP |
1392 | Example: dynamically allocate an \f(CW\*(C`ev_idle\*(C'\fR, start it, and in the |
1567 | Example: Dynamically allocate an \f(CW\*(C`ev_idle\*(C'\fR watcher, start it, and in the |
1393 | callback, free it. Alos, use no error checking, as usual. |
1568 | callback, free it. Also, use no error checking, as usual. |
1394 | .PP |
1569 | .PP |
1395 | .Vb 7 |
1570 | .Vb 7 |
1396 | \& static void |
1571 | \& static void |
1397 | \& idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
1572 | \& idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
1398 | \& { |
1573 | \& { |
… | |
… | |
1477 | \& if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
1652 | \& if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
1478 | \& if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
1653 | \& if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
1479 | \& } |
1654 | \& } |
1480 | .Ve |
1655 | .Ve |
1481 | .PP |
1656 | .PP |
1482 | .Vb 7 |
1657 | .Vb 8 |
1483 | \& // create io watchers for each fd and a timer before blocking |
1658 | \& // create io watchers for each fd and a timer before blocking |
1484 | \& static void |
1659 | \& static void |
1485 | \& adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
1660 | \& adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
1486 | \& { |
1661 | \& { |
1487 | \& int timeout = 3600000;truct pollfd fds [nfd]; |
1662 | \& int timeout = 3600000; |
|
|
1663 | \& struct pollfd fds [nfd]; |
1488 | \& // actual code will need to loop here and realloc etc. |
1664 | \& // actual code will need to loop here and realloc etc. |
1489 | \& adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
1665 | \& adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
1490 | .Ve |
1666 | .Ve |
1491 | .PP |
1667 | .PP |
1492 | .Vb 3 |
1668 | .Vb 3 |
… | |
… | |
1718 | .PP |
1894 | .PP |
1719 | .Vb 1 |
1895 | .Vb 1 |
1720 | \& #include <ev++.h> |
1896 | \& #include <ev++.h> |
1721 | .Ve |
1897 | .Ve |
1722 | .PP |
1898 | .PP |
1723 | (it is not installed by default). This automatically includes \fIev.h\fR |
1899 | This automatically includes \fIev.h\fR and puts all of its definitions (many |
1724 | and puts all of its definitions (many of them macros) into the global |
1900 | of them macros) into the global namespace. All \*(C+ specific things are |
1725 | namespace. All \*(C+ specific things are put into the \f(CW\*(C`ev\*(C'\fR namespace. |
1901 | put into the \f(CW\*(C`ev\*(C'\fR namespace. It should support all the same embedding |
|
|
1902 | options as \fIev.h\fR, most notably \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. |
1726 | .PP |
1903 | .PP |
1727 | It should support all the same embedding options as \fIev.h\fR, most notably |
1904 | Care has been taken to keep the overhead low. The only data member added |
1728 | \&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. |
1905 | to the C\-style watchers is the event loop the watcher is associated with |
|
|
1906 | (or no additional members at all if you disable \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR when |
|
|
1907 | embedding libev). |
|
|
1908 | .PP |
|
|
1909 | Currently, functions and static and non-static member functions can be |
|
|
1910 | used as callbacks. Other types should be easy to add as long as they only |
|
|
1911 | need one additional pointer for context. If you need support for other |
|
|
1912 | types of functors please contact the author (preferably after implementing |
|
|
1913 | it). |
1729 | .PP |
1914 | .PP |
1730 | Here is a list of things available in the \f(CW\*(C`ev\*(C'\fR namespace: |
1915 | Here is a list of things available in the \f(CW\*(C`ev\*(C'\fR namespace: |
1731 | .ie n .IP """ev::READ""\fR, \f(CW""ev::WRITE"" etc." 4 |
1916 | .ie n .IP """ev::READ""\fR, \f(CW""ev::WRITE"" etc." 4 |
1732 | .el .IP "\f(CWev::READ\fR, \f(CWev::WRITE\fR etc." 4 |
1917 | .el .IP "\f(CWev::READ\fR, \f(CWev::WRITE\fR etc." 4 |
1733 | .IX Item "ev::READ, ev::WRITE etc." |
1918 | .IX Item "ev::READ, ev::WRITE etc." |
… | |
… | |
1745 | which is called \f(CW\*(C`ev::sig\*(C'\fR to avoid clashes with the \f(CW\*(C`signal\*(C'\fR macro |
1930 | which is called \f(CW\*(C`ev::sig\*(C'\fR to avoid clashes with the \f(CW\*(C`signal\*(C'\fR macro |
1746 | defines by many implementations. |
1931 | defines by many implementations. |
1747 | .Sp |
1932 | .Sp |
1748 | All of those classes have these methods: |
1933 | All of those classes have these methods: |
1749 | .RS 4 |
1934 | .RS 4 |
1750 | .IP "ev::TYPE::TYPE (object *, object::method *)" 4 |
1935 | .IP "ev::TYPE::TYPE ()" 4 |
1751 | .IX Item "ev::TYPE::TYPE (object *, object::method *)" |
1936 | .IX Item "ev::TYPE::TYPE ()" |
1752 | .PD 0 |
1937 | .PD 0 |
1753 | .IP "ev::TYPE::TYPE (object *, object::method *, struct ev_loop *)" 4 |
1938 | .IP "ev::TYPE::TYPE (struct ev_loop *)" 4 |
1754 | .IX Item "ev::TYPE::TYPE (object *, object::method *, struct ev_loop *)" |
1939 | .IX Item "ev::TYPE::TYPE (struct ev_loop *)" |
1755 | .IP "ev::TYPE::~TYPE" 4 |
1940 | .IP "ev::TYPE::~TYPE" 4 |
1756 | .IX Item "ev::TYPE::~TYPE" |
1941 | .IX Item "ev::TYPE::~TYPE" |
1757 | .PD |
1942 | .PD |
1758 | The constructor takes a pointer to an object and a method pointer to |
1943 | The constructor (optionally) takes an event loop to associate the watcher |
1759 | the event handler callback to call in this class. The constructor calls |
1944 | with. If it is omitted, it will use \f(CW\*(C`EV_DEFAULT\*(C'\fR. |
1760 | \&\f(CW\*(C`ev_init\*(C'\fR for you, which means you have to call the \f(CW\*(C`set\*(C'\fR method |
1945 | .Sp |
1761 | before starting it. If you do not specify a loop then the constructor |
1946 | The constructor calls \f(CW\*(C`ev_init\*(C'\fR for you, which means you have to call the |
1762 | automatically associates the default loop with this watcher. |
1947 | \&\f(CW\*(C`set\*(C'\fR method before starting it. |
|
|
1948 | .Sp |
|
|
1949 | It will not set a callback, however: You have to call the templated \f(CW\*(C`set\*(C'\fR |
|
|
1950 | method to set a callback before you can start the watcher. |
|
|
1951 | .Sp |
|
|
1952 | (The reason why you have to use a method is a limitation in \*(C+ which does |
|
|
1953 | not allow explicit template arguments for constructors). |
1763 | .Sp |
1954 | .Sp |
1764 | The destructor automatically stops the watcher if it is active. |
1955 | The destructor automatically stops the watcher if it is active. |
|
|
1956 | .IP "w\->set<class, &class::method> (object *)" 4 |
|
|
1957 | .IX Item "w->set<class, &class::method> (object *)" |
|
|
1958 | This method sets the callback method to call. The method has to have a |
|
|
1959 | signature of \f(CW\*(C`void (*)(ev_TYPE &, int)\*(C'\fR, it receives the watcher as |
|
|
1960 | first argument and the \f(CW\*(C`revents\*(C'\fR as second. The object must be given as |
|
|
1961 | parameter and is stored in the \f(CW\*(C`data\*(C'\fR member of the watcher. |
|
|
1962 | .Sp |
|
|
1963 | This method synthesizes efficient thunking code to call your method from |
|
|
1964 | the C callback that libev requires. If your compiler can inline your |
|
|
1965 | callback (i.e. it is visible to it at the place of the \f(CW\*(C`set\*(C'\fR call and |
|
|
1966 | your compiler is good :), then the method will be fully inlined into the |
|
|
1967 | thunking function, making it as fast as a direct C callback. |
|
|
1968 | .Sp |
|
|
1969 | Example: simple class declaration and watcher initialisation |
|
|
1970 | .Sp |
|
|
1971 | .Vb 4 |
|
|
1972 | \& struct myclass |
|
|
1973 | \& { |
|
|
1974 | \& void io_cb (ev::io &w, int revents) { } |
|
|
1975 | \& } |
|
|
1976 | .Ve |
|
|
1977 | .Sp |
|
|
1978 | .Vb 3 |
|
|
1979 | \& myclass obj; |
|
|
1980 | \& ev::io iow; |
|
|
1981 | \& iow.set <myclass, &myclass::io_cb> (&obj); |
|
|
1982 | .Ve |
|
|
1983 | .IP "w\->set (void (*function)(watcher &w, int), void *data = 0)" 4 |
|
|
1984 | .IX Item "w->set (void (*function)(watcher &w, int), void *data = 0)" |
|
|
1985 | Also sets a callback, but uses a static method or plain function as |
|
|
1986 | callback. The optional \f(CW\*(C`data\*(C'\fR argument will be stored in the watcher's |
|
|
1987 | \&\f(CW\*(C`data\*(C'\fR member and is free for you to use. |
|
|
1988 | .Sp |
|
|
1989 | See the method\-\f(CW\*(C`set\*(C'\fR above for more details. |
1765 | .IP "w\->set (struct ev_loop *)" 4 |
1990 | .IP "w\->set (struct ev_loop *)" 4 |
1766 | .IX Item "w->set (struct ev_loop *)" |
1991 | .IX Item "w->set (struct ev_loop *)" |
1767 | Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only |
1992 | Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only |
1768 | do this when the watcher is inactive (and not pending either). |
1993 | do this when the watcher is inactive (and not pending either). |
1769 | .IP "w\->set ([args])" 4 |
1994 | .IP "w\->set ([args])" 4 |
1770 | .IX Item "w->set ([args])" |
1995 | .IX Item "w->set ([args])" |
1771 | Basically the same as \f(CW\*(C`ev_TYPE_set\*(C'\fR, with the same args. Must be |
1996 | Basically the same as \f(CW\*(C`ev_TYPE_set\*(C'\fR, with the same args. Must be |
1772 | called at least once. Unlike the C counterpart, an active watcher gets |
1997 | called at least once. Unlike the C counterpart, an active watcher gets |
1773 | automatically stopped and restarted. |
1998 | automatically stopped and restarted when reconfiguring it with this |
|
|
1999 | method. |
1774 | .IP "w\->start ()" 4 |
2000 | .IP "w\->start ()" 4 |
1775 | .IX Item "w->start ()" |
2001 | .IX Item "w->start ()" |
1776 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument as the |
2002 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument, as the |
1777 | constructor already takes the loop. |
2003 | constructor already stores the event loop. |
1778 | .IP "w\->stop ()" 4 |
2004 | .IP "w\->stop ()" 4 |
1779 | .IX Item "w->stop ()" |
2005 | .IX Item "w->stop ()" |
1780 | Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument. |
2006 | Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument. |
1781 | .ie n .IP "w\->again () ""ev::timer""\fR, \f(CW""ev::periodic"" only" 4 |
2007 | .ie n .IP "w\->again () ""ev::timer""\fR, \f(CW""ev::periodic"" only" 4 |
1782 | .el .IP "w\->again () \f(CWev::timer\fR, \f(CWev::periodic\fR only" 4 |
2008 | .el .IP "w\->again () \f(CWev::timer\fR, \f(CWev::periodic\fR only" 4 |
… | |
… | |
1808 | .Vb 2 |
2034 | .Vb 2 |
1809 | \& myclass (); |
2035 | \& myclass (); |
1810 | \& } |
2036 | \& } |
1811 | .Ve |
2037 | .Ve |
1812 | .PP |
2038 | .PP |
1813 | .Vb 6 |
2039 | .Vb 4 |
1814 | \& myclass::myclass (int fd) |
2040 | \& myclass::myclass (int fd) |
1815 | \& : io (this, &myclass::io_cb), |
|
|
1816 | \& idle (this, &myclass::idle_cb) |
|
|
1817 | \& { |
2041 | \& { |
|
|
2042 | \& io .set <myclass, &myclass::io_cb > (this); |
|
|
2043 | \& idle.set <myclass, &myclass::idle_cb> (this); |
|
|
2044 | .Ve |
|
|
2045 | .PP |
|
|
2046 | .Vb 2 |
1818 | \& io.start (fd, ev::READ); |
2047 | \& io.start (fd, ev::READ); |
1819 | \& } |
2048 | \& } |
1820 | .Ve |
2049 | .Ve |
1821 | .SH "MACRO MAGIC" |
2050 | .SH "MACRO MAGIC" |
1822 | .IX Header "MACRO MAGIC" |
2051 | .IX Header "MACRO MAGIC" |
1823 | Libev can be compiled with a variety of options, the most fundemantal is |
2052 | Libev can be compiled with a variety of options, the most fundemantal is |
1824 | \&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines wether (most) functions and |
2053 | \&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines whether (most) functions and |
1825 | callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument. |
2054 | callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument. |
1826 | .PP |
2055 | .PP |
1827 | To make it easier to write programs that cope with either variant, the |
2056 | To make it easier to write programs that cope with either variant, the |
1828 | following macros are defined: |
2057 | following macros are defined: |
1829 | .ie n .IP """EV_A""\fR, \f(CW""EV_A_""" 4 |
2058 | .ie n .IP """EV_A""\fR, \f(CW""EV_A_""" 4 |
… | |
… | |
1864 | .el .IP "\f(CWEV_DEFAULT\fR, \f(CWEV_DEFAULT_\fR" 4 |
2093 | .el .IP "\f(CWEV_DEFAULT\fR, \f(CWEV_DEFAULT_\fR" 4 |
1865 | .IX Item "EV_DEFAULT, EV_DEFAULT_" |
2094 | .IX Item "EV_DEFAULT, EV_DEFAULT_" |
1866 | Similar to the other two macros, this gives you the value of the default |
2095 | Similar to the other two macros, this gives you the value of the default |
1867 | loop, if multiple loops are supported (\*(L"ev loop default\*(R"). |
2096 | loop, if multiple loops are supported (\*(L"ev loop default\*(R"). |
1868 | .PP |
2097 | .PP |
1869 | Example: Declare and initialise a check watcher, working regardless of |
2098 | Example: Declare and initialise a check watcher, utilising the above |
1870 | wether multiple loops are supported or not. |
2099 | macros so it will work regardless of whether multiple loops are supported |
|
|
2100 | or not. |
1871 | .PP |
2101 | .PP |
1872 | .Vb 5 |
2102 | .Vb 5 |
1873 | \& static void |
2103 | \& static void |
1874 | \& check_cb (EV_P_ ev_timer *w, int revents) |
2104 | \& check_cb (EV_P_ ev_timer *w, int revents) |
1875 | \& { |
2105 | \& { |
… | |
… | |
1938 | .Vb 1 |
2168 | .Vb 1 |
1939 | \& ev_win32.c required on win32 platforms only |
2169 | \& ev_win32.c required on win32 platforms only |
1940 | .Ve |
2170 | .Ve |
1941 | .PP |
2171 | .PP |
1942 | .Vb 5 |
2172 | .Vb 5 |
1943 | \& ev_select.c only when select backend is enabled (which is by default) |
2173 | \& ev_select.c only when select backend is enabled (which is enabled by default) |
1944 | \& ev_poll.c only when poll backend is enabled (disabled by default) |
2174 | \& ev_poll.c only when poll backend is enabled (disabled by default) |
1945 | \& ev_epoll.c only when the epoll backend is enabled (disabled by default) |
2175 | \& ev_epoll.c only when the epoll backend is enabled (disabled by default) |
1946 | \& ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
2176 | \& ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
1947 | \& ev_port.c only when the solaris port backend is enabled (disabled by default) |
2177 | \& ev_port.c only when the solaris port backend is enabled (disabled by default) |
1948 | .Ve |
2178 | .Ve |
… | |
… | |
2069 | otherwise another method will be used as fallback. This is the preferred |
2299 | otherwise another method will be used as fallback. This is the preferred |
2070 | backend for Solaris 10 systems. |
2300 | backend for Solaris 10 systems. |
2071 | .IP "\s-1EV_USE_DEVPOLL\s0" 4 |
2301 | .IP "\s-1EV_USE_DEVPOLL\s0" 4 |
2072 | .IX Item "EV_USE_DEVPOLL" |
2302 | .IX Item "EV_USE_DEVPOLL" |
2073 | reserved for future expansion, works like the \s-1USE\s0 symbols above. |
2303 | reserved for future expansion, works like the \s-1USE\s0 symbols above. |
|
|
2304 | .IP "\s-1EV_USE_INOTIFY\s0" 4 |
|
|
2305 | .IX Item "EV_USE_INOTIFY" |
|
|
2306 | If defined to be \f(CW1\fR, libev will compile in support for the Linux inotify |
|
|
2307 | interface to speed up \f(CW\*(C`ev_stat\*(C'\fR watchers. Its actual availability will |
|
|
2308 | be detected at runtime. |
2074 | .IP "\s-1EV_H\s0" 4 |
2309 | .IP "\s-1EV_H\s0" 4 |
2075 | .IX Item "EV_H" |
2310 | .IX Item "EV_H" |
2076 | The name of the \fIev.h\fR header file used to include it. The default if |
2311 | The name of the \fIev.h\fR header file used to include it. The default if |
2077 | undefined is \f(CW\*(C`<ev.h>\*(C'\fR in \fIevent.h\fR and \f(CW"ev.h"\fR in \fIev.c\fR. This |
2312 | undefined is \f(CW\*(C`<ev.h>\*(C'\fR in \fIevent.h\fR and \f(CW"ev.h"\fR in \fIev.c\fR. This |
2078 | can be used to virtually rename the \fIev.h\fR header file in case of conflicts. |
2313 | can be used to virtually rename the \fIev.h\fR header file in case of conflicts. |
… | |
… | |
2096 | If undefined or defined to \f(CW1\fR, then all event-loop-specific functions |
2331 | If undefined or defined to \f(CW1\fR, then all event-loop-specific functions |
2097 | will have the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument, and you can create |
2332 | will have the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument, and you can create |
2098 | additional independent event loops. Otherwise there will be no support |
2333 | additional independent event loops. Otherwise there will be no support |
2099 | for multiple event loops and there is no first event loop pointer |
2334 | for multiple event loops and there is no first event loop pointer |
2100 | argument. Instead, all functions act on the single default loop. |
2335 | argument. Instead, all functions act on the single default loop. |
|
|
2336 | .IP "\s-1EV_MINPRI\s0" 4 |
|
|
2337 | .IX Item "EV_MINPRI" |
|
|
2338 | .PD 0 |
|
|
2339 | .IP "\s-1EV_MAXPRI\s0" 4 |
|
|
2340 | .IX Item "EV_MAXPRI" |
|
|
2341 | .PD |
|
|
2342 | The range of allowed priorities. \f(CW\*(C`EV_MINPRI\*(C'\fR must be smaller or equal to |
|
|
2343 | \&\f(CW\*(C`EV_MAXPRI\*(C'\fR, but otherwise there are no non-obvious limitations. You can |
|
|
2344 | provide for more priorities by overriding those symbols (usually defined |
|
|
2345 | to be \f(CW\*(C`\-2\*(C'\fR and \f(CW2\fR, respectively). |
|
|
2346 | .Sp |
|
|
2347 | When doing priority-based operations, libev usually has to linearly search |
|
|
2348 | all the priorities, so having many of them (hundreds) uses a lot of space |
|
|
2349 | and time, so using the defaults of five priorities (\-2 .. +2) is usually |
|
|
2350 | fine. |
|
|
2351 | .Sp |
|
|
2352 | If your embedding app does not need any priorities, defining these both to |
|
|
2353 | \&\f(CW0\fR will save some memory and cpu. |
2101 | .IP "\s-1EV_PERIODIC_ENABLE\s0" 4 |
2354 | .IP "\s-1EV_PERIODIC_ENABLE\s0" 4 |
2102 | .IX Item "EV_PERIODIC_ENABLE" |
2355 | .IX Item "EV_PERIODIC_ENABLE" |
2103 | If undefined or defined to be \f(CW1\fR, then periodic timers are supported. If |
2356 | If undefined or defined to be \f(CW1\fR, then periodic timers are supported. If |
|
|
2357 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
|
|
2358 | code. |
|
|
2359 | .IP "\s-1EV_IDLE_ENABLE\s0" 4 |
|
|
2360 | .IX Item "EV_IDLE_ENABLE" |
|
|
2361 | If undefined or defined to be \f(CW1\fR, then idle watchers are supported. If |
2104 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
2362 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
2105 | code. |
2363 | code. |
2106 | .IP "\s-1EV_EMBED_ENABLE\s0" 4 |
2364 | .IP "\s-1EV_EMBED_ENABLE\s0" 4 |
2107 | .IX Item "EV_EMBED_ENABLE" |
2365 | .IX Item "EV_EMBED_ENABLE" |
2108 | If undefined or defined to be \f(CW1\fR, then embed watchers are supported. If |
2366 | If undefined or defined to be \f(CW1\fR, then embed watchers are supported. If |
… | |
… | |
2123 | .IP "\s-1EV_PID_HASHSIZE\s0" 4 |
2381 | .IP "\s-1EV_PID_HASHSIZE\s0" 4 |
2124 | .IX Item "EV_PID_HASHSIZE" |
2382 | .IX Item "EV_PID_HASHSIZE" |
2125 | \&\f(CW\*(C`ev_child\*(C'\fR watchers use a small hash table to distribute workload by |
2383 | \&\f(CW\*(C`ev_child\*(C'\fR watchers use a small hash table to distribute workload by |
2126 | pid. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), usually more |
2384 | pid. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), usually more |
2127 | than enough. If you need to manage thousands of children you might want to |
2385 | than enough. If you need to manage thousands of children you might want to |
2128 | increase this value. |
2386 | increase this value (\fImust\fR be a power of two). |
|
|
2387 | .IP "\s-1EV_INOTIFY_HASHSIZE\s0" 4 |
|
|
2388 | .IX Item "EV_INOTIFY_HASHSIZE" |
|
|
2389 | \&\f(CW\*(C`ev_staz\*(C'\fR watchers use a small hash table to distribute workload by |
|
|
2390 | inotify watch id. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), |
|
|
2391 | usually more than enough. If you need to manage thousands of \f(CW\*(C`ev_stat\*(C'\fR |
|
|
2392 | watchers you might want to increase this value (\fImust\fR be a power of |
|
|
2393 | two). |
2129 | .IP "\s-1EV_COMMON\s0" 4 |
2394 | .IP "\s-1EV_COMMON\s0" 4 |
2130 | .IX Item "EV_COMMON" |
2395 | .IX Item "EV_COMMON" |
2131 | By default, all watchers have a \f(CW\*(C`void *data\*(C'\fR member. By redefining |
2396 | By default, all watchers have a \f(CW\*(C`void *data\*(C'\fR member. By redefining |
2132 | this macro to a something else you can include more and other types of |
2397 | this macro to a something else you can include more and other types of |
2133 | members. You have to define it each time you include one of the files, |
2398 | members. You have to define it each time you include one of the files, |
… | |
… | |
2163 | interface) and \fI\s-1EV\s0.xs\fR (implementation) files. Only the \fI\s-1EV\s0.xs\fR file |
2428 | interface) and \fI\s-1EV\s0.xs\fR (implementation) files. Only the \fI\s-1EV\s0.xs\fR file |
2164 | will be compiled. It is pretty complex because it provides its own header |
2429 | will be compiled. It is pretty complex because it provides its own header |
2165 | file. |
2430 | file. |
2166 | .Sp |
2431 | .Sp |
2167 | The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file |
2432 | The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file |
2168 | that everybody includes and which overrides some autoconf choices: |
2433 | that everybody includes and which overrides some configure choices: |
2169 | .Sp |
2434 | .Sp |
2170 | .Vb 4 |
2435 | .Vb 9 |
|
|
2436 | \& #define EV_MINIMAL 1 |
2171 | \& #define EV_USE_POLL 0 |
2437 | \& #define EV_USE_POLL 0 |
2172 | \& #define EV_MULTIPLICITY 0 |
2438 | \& #define EV_MULTIPLICITY 0 |
2173 | \& #define EV_PERIODICS 0 |
2439 | \& #define EV_PERIODIC_ENABLE 0 |
|
|
2440 | \& #define EV_STAT_ENABLE 0 |
|
|
2441 | \& #define EV_FORK_ENABLE 0 |
2174 | \& #define EV_CONFIG_H <config.h> |
2442 | \& #define EV_CONFIG_H <config.h> |
|
|
2443 | \& #define EV_MINPRI 0 |
|
|
2444 | \& #define EV_MAXPRI 0 |
2175 | .Ve |
2445 | .Ve |
2176 | .Sp |
2446 | .Sp |
2177 | .Vb 1 |
2447 | .Vb 1 |
2178 | \& #include "ev++.h" |
2448 | \& #include "ev++.h" |
2179 | .Ve |
2449 | .Ve |
… | |
… | |
2187 | .SH "COMPLEXITIES" |
2457 | .SH "COMPLEXITIES" |
2188 | .IX Header "COMPLEXITIES" |
2458 | .IX Header "COMPLEXITIES" |
2189 | In this section the complexities of (many of) the algorithms used inside |
2459 | In this section the complexities of (many of) the algorithms used inside |
2190 | libev will be explained. For complexity discussions about backends see the |
2460 | libev will be explained. For complexity discussions about backends see the |
2191 | documentation for \f(CW\*(C`ev_default_init\*(C'\fR. |
2461 | documentation for \f(CW\*(C`ev_default_init\*(C'\fR. |
|
|
2462 | .Sp |
|
|
2463 | All of the following are about amortised time: If an array needs to be |
|
|
2464 | extended, libev needs to realloc and move the whole array, but this |
|
|
2465 | happens asymptotically never with higher number of elements, so O(1) might |
|
|
2466 | mean it might do a lengthy realloc operation in rare cases, but on average |
|
|
2467 | it is much faster and asymptotically approaches constant time. |
2192 | .RS 4 |
2468 | .RS 4 |
2193 | .IP "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" 4 |
2469 | .IP "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" 4 |
2194 | .IX Item "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" |
2470 | .IX Item "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" |
2195 | .PD 0 |
2471 | This means that, when you have a watcher that triggers in one hour and |
|
|
2472 | there are 100 watchers that would trigger before that then inserting will |
|
|
2473 | have to skip those 100 watchers. |
2196 | .IP "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" 4 |
2474 | .IP "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" 4 |
2197 | .IX Item "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" |
2475 | .IX Item "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" |
|
|
2476 | That means that for changing a timer costs less than removing/adding them |
|
|
2477 | as only the relative motion in the event queue has to be paid for. |
2198 | .IP "Starting io/check/prepare/idle/signal/child watchers: O(1)" 4 |
2478 | .IP "Starting io/check/prepare/idle/signal/child watchers: O(1)" 4 |
2199 | .IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)" |
2479 | .IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)" |
2200 | .IP "Stopping check/prepare/idle watchers: O(1)" 4 |
2480 | These just add the watcher into an array or at the head of a list. |
2201 | .IX Item "Stopping check/prepare/idle watchers: O(1)" |
2481 | =item Stopping check/prepare/idle watchers: O(1) |
2202 | .IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % 16))" 4 |
2482 | .IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % \s-1EV_PID_HASHSIZE\s0))" 4 |
2203 | .IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % 16))" |
2483 | .IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))" |
|
|
2484 | These watchers are stored in lists then need to be walked to find the |
|
|
2485 | correct watcher to remove. The lists are usually short (you don't usually |
|
|
2486 | have many watchers waiting for the same fd or signal). |
2204 | .IP "Finding the next timer per loop iteration: O(1)" 4 |
2487 | .IP "Finding the next timer per loop iteration: O(1)" 4 |
2205 | .IX Item "Finding the next timer per loop iteration: O(1)" |
2488 | .IX Item "Finding the next timer per loop iteration: O(1)" |
|
|
2489 | .PD 0 |
2206 | .IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4 |
2490 | .IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4 |
2207 | .IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" |
2491 | .IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" |
|
|
2492 | .PD |
|
|
2493 | A change means an I/O watcher gets started or stopped, which requires |
|
|
2494 | libev to recalculate its status (and possibly tell the kernel). |
2208 | .IP "Activating one watcher: O(1)" 4 |
2495 | .IP "Activating one watcher: O(1)" 4 |
2209 | .IX Item "Activating one watcher: O(1)" |
2496 | .IX Item "Activating one watcher: O(1)" |
|
|
2497 | .PD 0 |
|
|
2498 | .IP "Priority handling: O(number_of_priorities)" 4 |
|
|
2499 | .IX Item "Priority handling: O(number_of_priorities)" |
|
|
2500 | .PD |
|
|
2501 | Priorities are implemented by allocating some space for each |
|
|
2502 | priority. When doing priority-based operations, libev usually has to |
|
|
2503 | linearly search all the priorities. |
2210 | .RE |
2504 | .RE |
2211 | .RS 4 |
2505 | .RS 4 |
2212 | .PD |
|
|
2213 | .SH "AUTHOR" |
2506 | .SH "AUTHOR" |
2214 | .IX Header "AUTHOR" |
2507 | .IX Header "AUTHOR" |
2215 | Marc Lehmann <libev@schmorp.de>. |
2508 | Marc Lehmann <libev@schmorp.de>. |