… | |
… | |
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 "2007-11-26" "perl v5.8.8" "User Contributed Perl Documentation" |
132 | .TH "<STANDARD INPUT>" 1 "2007-12-09" "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 |
… | |
… | |
535 | libev watchers. However, a pair of \f(CW\*(C`ev_prepare\*(C'\fR/\f(CW\*(C`ev_check\*(C'\fR watchers is |
634 | 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. |
635 | usually a better approach for this kind of thing. |
537 | .Sp |
636 | .Sp |
538 | Here are the gory details of what \f(CW\*(C`ev_loop\*(C'\fR does: |
637 | Here are the gory details of what \f(CW\*(C`ev_loop\*(C'\fR does: |
539 | .Sp |
638 | .Sp |
540 | .Vb 18 |
639 | .Vb 19 |
|
|
640 | \& - Before the first iteration, call any pending watchers. |
541 | \& * If there are no active watchers (reference count is zero), return. |
641 | \& * If there are no active watchers (reference count is zero), return. |
542 | \& - Queue prepare watchers and then call all outstanding watchers. |
642 | \& - Queue all prepare watchers and then call all outstanding watchers. |
543 | \& - If we have been forked, recreate the kernel state. |
643 | \& - If we have been forked, recreate the kernel state. |
544 | \& - Update the kernel state with all outstanding changes. |
644 | \& - Update the kernel state with all outstanding changes. |
545 | \& - Update the "event loop time". |
645 | \& - Update the "event loop time". |
546 | \& - Calculate for how long to block. |
646 | \& - Calculate for how long to block. |
547 | \& - Block the process, waiting for any events. |
647 | \& - Block the process, waiting for any events. |
… | |
… | |
556 | \& be handled here by queueing them when their watcher gets executed. |
656 | \& be handled here by queueing them when their watcher gets executed. |
557 | \& - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
657 | \& - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
558 | \& were used, return, otherwise continue with step *. |
658 | \& were used, return, otherwise continue with step *. |
559 | .Ve |
659 | .Ve |
560 | .Sp |
660 | .Sp |
561 | Example: queue some jobs and then loop until no events are outsanding |
661 | Example: Queue some jobs and then loop until no events are outsanding |
562 | anymore. |
662 | anymore. |
563 | .Sp |
663 | .Sp |
564 | .Vb 4 |
664 | .Vb 4 |
565 | \& ... queue jobs here, make sure they register event watchers as long |
665 | \& ... 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..) |
666 | \& ... 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 |
688 | 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 |
689 | 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 |
690 | 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. |
691 | libraries. Just remember to \fIunref after start\fR and \fIref before stop\fR. |
592 | .Sp |
692 | .Sp |
593 | Example: create a signal watcher, but keep it from keeping \f(CW\*(C`ev_loop\*(C'\fR |
693 | Example: Create a signal watcher, but keep it from keeping \f(CW\*(C`ev_loop\*(C'\fR |
594 | running when nothing else is active. |
694 | running when nothing else is active. |
595 | .Sp |
695 | .Sp |
596 | .Vb 4 |
696 | .Vb 4 |
597 | \& struct dv_signal exitsig; |
697 | \& struct ev_signal exitsig; |
598 | \& ev_signal_init (&exitsig, sig_cb, SIGINT); |
698 | \& ev_signal_init (&exitsig, sig_cb, SIGINT); |
599 | \& ev_signal_start (myloop, &exitsig); |
699 | \& ev_signal_start (loop, &exitsig); |
600 | \& evf_unref (myloop); |
700 | \& evf_unref (loop); |
601 | .Ve |
701 | .Ve |
602 | .Sp |
702 | .Sp |
603 | Example: for some weird reason, unregister the above signal handler again. |
703 | Example: For some weird reason, unregister the above signal handler again. |
604 | .Sp |
704 | .Sp |
605 | .Vb 2 |
705 | .Vb 2 |
606 | \& ev_ref (myloop); |
706 | \& ev_ref (loop); |
607 | \& ev_signal_stop (myloop, &exitsig); |
707 | \& ev_signal_stop (loop, &exitsig); |
608 | .Ve |
708 | .Ve |
609 | .SH "ANATOMY OF A WATCHER" |
709 | .SH "ANATOMY OF A WATCHER" |
610 | .IX Header "ANATOMY OF A WATCHER" |
710 | .IX Header "ANATOMY OF A WATCHER" |
611 | A watcher is a structure that you create and register to record your |
711 | 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 |
712 | interest in some event. For instance, if you want to wait for \s-1STDIN\s0 to |
… | |
… | |
684 | The signal specified in the \f(CW\*(C`ev_signal\*(C'\fR watcher has been received by a thread. |
784 | The signal specified in the \f(CW\*(C`ev_signal\*(C'\fR watcher has been received by a thread. |
685 | .ie n .IP """EV_CHILD""" 4 |
785 | .ie n .IP """EV_CHILD""" 4 |
686 | .el .IP "\f(CWEV_CHILD\fR" 4 |
786 | .el .IP "\f(CWEV_CHILD\fR" 4 |
687 | .IX Item "EV_CHILD" |
787 | .IX Item "EV_CHILD" |
688 | The pid specified in the \f(CW\*(C`ev_child\*(C'\fR watcher has received a status change. |
788 | The pid specified in the \f(CW\*(C`ev_child\*(C'\fR watcher has received a status change. |
|
|
789 | .ie n .IP """EV_STAT""" 4 |
|
|
790 | .el .IP "\f(CWEV_STAT\fR" 4 |
|
|
791 | .IX Item "EV_STAT" |
|
|
792 | The path specified in the \f(CW\*(C`ev_stat\*(C'\fR watcher changed its attributes somehow. |
689 | .ie n .IP """EV_IDLE""" 4 |
793 | .ie n .IP """EV_IDLE""" 4 |
690 | .el .IP "\f(CWEV_IDLE\fR" 4 |
794 | .el .IP "\f(CWEV_IDLE\fR" 4 |
691 | .IX Item "EV_IDLE" |
795 | .IX Item "EV_IDLE" |
692 | The \f(CW\*(C`ev_idle\*(C'\fR watcher has determined that you have nothing better to do. |
796 | The \f(CW\*(C`ev_idle\*(C'\fR watcher has determined that you have nothing better to do. |
693 | .ie n .IP """EV_PREPARE""" 4 |
797 | .ie n .IP """EV_PREPARE""" 4 |
… | |
… | |
703 | \&\f(CW\*(C`ev_loop\*(C'\fR has gathered them, but before it invokes any callbacks for any |
807 | \&\f(CW\*(C`ev_loop\*(C'\fR has gathered them, but before it invokes any callbacks for any |
704 | received events. Callbacks of both watcher types can start and stop as |
808 | received events. Callbacks of both watcher types can start and stop as |
705 | many watchers as they want, and all of them will be taken into account |
809 | many watchers as they want, and all of them will be taken into account |
706 | (for example, a \f(CW\*(C`ev_prepare\*(C'\fR watcher might start an idle watcher to keep |
810 | (for example, a \f(CW\*(C`ev_prepare\*(C'\fR watcher might start an idle watcher to keep |
707 | \&\f(CW\*(C`ev_loop\*(C'\fR from blocking). |
811 | \&\f(CW\*(C`ev_loop\*(C'\fR from blocking). |
|
|
812 | .ie n .IP """EV_EMBED""" 4 |
|
|
813 | .el .IP "\f(CWEV_EMBED\fR" 4 |
|
|
814 | .IX Item "EV_EMBED" |
|
|
815 | The embedded event loop specified in the \f(CW\*(C`ev_embed\*(C'\fR watcher needs attention. |
|
|
816 | .ie n .IP """EV_FORK""" 4 |
|
|
817 | .el .IP "\f(CWEV_FORK\fR" 4 |
|
|
818 | .IX Item "EV_FORK" |
|
|
819 | The event loop has been resumed in the child process after fork (see |
|
|
820 | \&\f(CW\*(C`ev_fork\*(C'\fR). |
708 | .ie n .IP """EV_ERROR""" 4 |
821 | .ie n .IP """EV_ERROR""" 4 |
709 | .el .IP "\f(CWEV_ERROR\fR" 4 |
822 | .el .IP "\f(CWEV_ERROR\fR" 4 |
710 | .IX Item "EV_ERROR" |
823 | .IX Item "EV_ERROR" |
711 | An unspecified error has occured, the watcher has been stopped. This might |
824 | An unspecified error has occured, the watcher has been stopped. This might |
712 | happen because the watcher could not be properly started because libev |
825 | happen because the watcher could not be properly started because libev |
… | |
… | |
777 | .IP "bool ev_is_pending (ev_TYPE *watcher)" 4 |
890 | .IP "bool ev_is_pending (ev_TYPE *watcher)" 4 |
778 | .IX Item "bool ev_is_pending (ev_TYPE *watcher)" |
891 | .IX Item "bool ev_is_pending (ev_TYPE *watcher)" |
779 | Returns a true value iff the watcher is pending, (i.e. it has outstanding |
892 | Returns a true value iff the watcher is pending, (i.e. it has outstanding |
780 | events but its callback has not yet been invoked). As long as a watcher |
893 | events but its callback has not yet been invoked). As long as a watcher |
781 | is pending (but not active) you must not call an init function on it (but |
894 | is pending (but not active) you must not call an init function on it (but |
782 | \&\f(CW\*(C`ev_TYPE_set\*(C'\fR is safe) and you must make sure the watcher is available to |
895 | \&\f(CW\*(C`ev_TYPE_set\*(C'\fR is safe), you must not change its priority, and you must |
783 | libev (e.g. you cnanot \f(CW\*(C`free ()\*(C'\fR it). |
896 | make sure the watcher is available to libev (e.g. you cannot \f(CW\*(C`free ()\*(C'\fR |
|
|
897 | it). |
784 | .IP "callback = ev_cb (ev_TYPE *watcher)" 4 |
898 | .IP "callback ev_cb (ev_TYPE *watcher)" 4 |
785 | .IX Item "callback = ev_cb (ev_TYPE *watcher)" |
899 | .IX Item "callback ev_cb (ev_TYPE *watcher)" |
786 | Returns the callback currently set on the watcher. |
900 | Returns the callback currently set on the watcher. |
787 | .IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 |
901 | .IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 |
788 | .IX Item "ev_cb_set (ev_TYPE *watcher, callback)" |
902 | .IX Item "ev_cb_set (ev_TYPE *watcher, callback)" |
789 | Change the callback. You can change the callback at virtually any time |
903 | Change the callback. You can change the callback at virtually any time |
790 | (modulo threads). |
904 | (modulo threads). |
|
|
905 | .IP "ev_set_priority (ev_TYPE *watcher, priority)" 4 |
|
|
906 | .IX Item "ev_set_priority (ev_TYPE *watcher, priority)" |
|
|
907 | .PD 0 |
|
|
908 | .IP "int ev_priority (ev_TYPE *watcher)" 4 |
|
|
909 | .IX Item "int ev_priority (ev_TYPE *watcher)" |
|
|
910 | .PD |
|
|
911 | Set and query the priority of the watcher. The priority is a small |
|
|
912 | integer between \f(CW\*(C`EV_MAXPRI\*(C'\fR (default: \f(CW2\fR) and \f(CW\*(C`EV_MINPRI\*(C'\fR |
|
|
913 | (default: \f(CW\*(C`\-2\*(C'\fR). Pending watchers with higher priority will be invoked |
|
|
914 | before watchers with lower priority, but priority will not keep watchers |
|
|
915 | from being executed (except for \f(CW\*(C`ev_idle\*(C'\fR watchers). |
|
|
916 | .Sp |
|
|
917 | This means that priorities are \fIonly\fR used for ordering callback |
|
|
918 | invocation after new events have been received. This is useful, for |
|
|
919 | example, to reduce latency after idling, or more often, to bind two |
|
|
920 | watchers on the same event and make sure one is called first. |
|
|
921 | .Sp |
|
|
922 | If you need to suppress invocation when higher priority events are pending |
|
|
923 | you need to look at \f(CW\*(C`ev_idle\*(C'\fR watchers, which provide this functionality. |
|
|
924 | .Sp |
|
|
925 | You \fImust not\fR change the priority of a watcher as long as it is active or |
|
|
926 | pending. |
|
|
927 | .Sp |
|
|
928 | The default priority used by watchers when no priority has been set is |
|
|
929 | always \f(CW0\fR, which is supposed to not be too high and not be too low :). |
|
|
930 | .Sp |
|
|
931 | Setting a priority outside the range of \f(CW\*(C`EV_MINPRI\*(C'\fR to \f(CW\*(C`EV_MAXPRI\*(C'\fR is |
|
|
932 | fine, as long as you do not mind that the priority value you query might |
|
|
933 | or might not have been adjusted to be within valid range. |
|
|
934 | .IP "ev_invoke (loop, ev_TYPE *watcher, int revents)" 4 |
|
|
935 | .IX Item "ev_invoke (loop, ev_TYPE *watcher, int revents)" |
|
|
936 | 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 |
|
|
937 | \&\f(CW\*(C`loop\*(C'\fR nor \f(CW\*(C`revents\*(C'\fR need to be valid as long as the watcher callback |
|
|
938 | can deal with that fact. |
|
|
939 | .IP "int ev_clear_pending (loop, ev_TYPE *watcher)" 4 |
|
|
940 | .IX Item "int ev_clear_pending (loop, ev_TYPE *watcher)" |
|
|
941 | If the watcher is pending, this function returns clears its pending status |
|
|
942 | and returns its \f(CW\*(C`revents\*(C'\fR bitset (as if its callback was invoked). If the |
|
|
943 | watcher isn't pending it does nothing and returns \f(CW0\fR. |
791 | .Sh "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0" |
944 | .Sh "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0" |
792 | .IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER" |
945 | .IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER" |
793 | Each watcher has, by default, a member \f(CW\*(C`void *data\*(C'\fR that you can change |
946 | Each watcher has, by default, a member \f(CW\*(C`void *data\*(C'\fR that you can change |
794 | and read at any time, libev will completely ignore it. This can be used |
947 | and read at any time, libev will completely ignore it. This can be used |
795 | to associate arbitrary data with your watcher. If you need more data and |
948 | to associate arbitrary data with your watcher. If you need more data and |
… | |
… | |
816 | \& struct my_io *w = (struct my_io *)w_; |
969 | \& struct my_io *w = (struct my_io *)w_; |
817 | \& ... |
970 | \& ... |
818 | \& } |
971 | \& } |
819 | .Ve |
972 | .Ve |
820 | .PP |
973 | .PP |
821 | More interesting and less C\-conformant ways of catsing your callback type |
974 | More interesting and less C\-conformant ways of casting your callback type |
822 | have been omitted.... |
975 | instead have been omitted. |
|
|
976 | .PP |
|
|
977 | Another common scenario is having some data structure with multiple |
|
|
978 | watchers: |
|
|
979 | .PP |
|
|
980 | .Vb 6 |
|
|
981 | \& struct my_biggy |
|
|
982 | \& { |
|
|
983 | \& int some_data; |
|
|
984 | \& ev_timer t1; |
|
|
985 | \& ev_timer t2; |
|
|
986 | \& } |
|
|
987 | .Ve |
|
|
988 | .PP |
|
|
989 | In this case getting the pointer to \f(CW\*(C`my_biggy\*(C'\fR is a bit more complicated, |
|
|
990 | you need to use \f(CW\*(C`offsetof\*(C'\fR: |
|
|
991 | .PP |
|
|
992 | .Vb 1 |
|
|
993 | \& #include <stddef.h> |
|
|
994 | .Ve |
|
|
995 | .PP |
|
|
996 | .Vb 6 |
|
|
997 | \& static void |
|
|
998 | \& t1_cb (EV_P_ struct ev_timer *w, int revents) |
|
|
999 | \& { |
|
|
1000 | \& struct my_biggy big = (struct my_biggy * |
|
|
1001 | \& (((char *)w) - offsetof (struct my_biggy, t1)); |
|
|
1002 | \& } |
|
|
1003 | .Ve |
|
|
1004 | .PP |
|
|
1005 | .Vb 6 |
|
|
1006 | \& static void |
|
|
1007 | \& t2_cb (EV_P_ struct ev_timer *w, int revents) |
|
|
1008 | \& { |
|
|
1009 | \& struct my_biggy big = (struct my_biggy * |
|
|
1010 | \& (((char *)w) - offsetof (struct my_biggy, t2)); |
|
|
1011 | \& } |
|
|
1012 | .Ve |
823 | .SH "WATCHER TYPES" |
1013 | .SH "WATCHER TYPES" |
824 | .IX Header "WATCHER TYPES" |
1014 | .IX Header "WATCHER TYPES" |
825 | This section describes each watcher in detail, but will not repeat |
1015 | This section describes each watcher in detail, but will not repeat |
826 | information given in the last section. |
1016 | information given in the last section. Any initialisation/set macros, |
|
|
1017 | functions and members specific to the watcher type are explained. |
|
|
1018 | .PP |
|
|
1019 | Members are additionally marked with either \fI[read\-only]\fR, meaning that, |
|
|
1020 | while the watcher is active, you can look at the member and expect some |
|
|
1021 | sensible content, but you must not modify it (you can modify it while the |
|
|
1022 | watcher is stopped to your hearts content), or \fI[read\-write]\fR, which |
|
|
1023 | means you can expect it to have some sensible content while the watcher |
|
|
1024 | is active, but you can also modify it. Modifying it may not do something |
|
|
1025 | sensible or take immediate effect (or do anything at all), but libev will |
|
|
1026 | not crash or malfunction in any way. |
827 | .ie n .Sh """ev_io"" \- is this file descriptor readable or writable?" |
1027 | .ie n .Sh """ev_io"" \- is this file descriptor readable or writable?" |
828 | .el .Sh "\f(CWev_io\fP \- is this file descriptor readable or writable?" |
1028 | .el .Sh "\f(CWev_io\fP \- is this file descriptor readable or writable?" |
829 | .IX Subsection "ev_io - is this file descriptor readable or writable?" |
1029 | .IX Subsection "ev_io - is this file descriptor readable or writable?" |
830 | I/O watchers check whether a file descriptor is readable or writable |
1030 | I/O watchers check whether a file descriptor is readable or writable |
831 | in each iteration of the event loop, or, more precisely, when reading |
1031 | in each iteration of the event loop, or, more precisely, when reading |
… | |
… | |
859 | it is best to always use non-blocking I/O: An extra \f(CW\*(C`read\*(C'\fR(2) returning |
1059 | it is best to always use non-blocking I/O: An extra \f(CW\*(C`read\*(C'\fR(2) returning |
860 | \&\f(CW\*(C`EAGAIN\*(C'\fR is far preferable to a program hanging until some data arrives. |
1060 | \&\f(CW\*(C`EAGAIN\*(C'\fR is far preferable to a program hanging until some data arrives. |
861 | .PP |
1061 | .PP |
862 | If you cannot run the fd in non-blocking mode (for example you should not |
1062 | If you cannot run the fd in non-blocking mode (for example you should not |
863 | play around with an Xlib connection), then you have to seperately re-test |
1063 | play around with an Xlib connection), then you have to seperately re-test |
864 | wether a file descriptor is really ready with a known-to-be good interface |
1064 | whether a file descriptor is really ready with a known-to-be good interface |
865 | such as poll (fortunately in our Xlib example, Xlib already does this on |
1065 | such as poll (fortunately in our Xlib example, Xlib already does this on |
866 | its own, so its quite safe to use). |
1066 | its own, so its quite safe to use). |
867 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
1067 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
868 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
1068 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
869 | .PD 0 |
1069 | .PD 0 |
… | |
… | |
871 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
1071 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
872 | .PD |
1072 | .PD |
873 | Configures an \f(CW\*(C`ev_io\*(C'\fR watcher. The \f(CW\*(C`fd\*(C'\fR is the file descriptor to |
1073 | Configures an \f(CW\*(C`ev_io\*(C'\fR watcher. The \f(CW\*(C`fd\*(C'\fR is the file descriptor to |
874 | rceeive events for and events is either \f(CW\*(C`EV_READ\*(C'\fR, \f(CW\*(C`EV_WRITE\*(C'\fR or |
1074 | rceeive events for and events is either \f(CW\*(C`EV_READ\*(C'\fR, \f(CW\*(C`EV_WRITE\*(C'\fR or |
875 | \&\f(CW\*(C`EV_READ | EV_WRITE\*(C'\fR to receive the given events. |
1075 | \&\f(CW\*(C`EV_READ | EV_WRITE\*(C'\fR to receive the given events. |
|
|
1076 | .IP "int fd [read\-only]" 4 |
|
|
1077 | .IX Item "int fd [read-only]" |
|
|
1078 | The file descriptor being watched. |
|
|
1079 | .IP "int events [read\-only]" 4 |
|
|
1080 | .IX Item "int events [read-only]" |
|
|
1081 | The events being watched. |
876 | .PP |
1082 | .PP |
877 | Example: call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well |
1083 | Example: Call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well |
878 | readable, but only once. Since it is likely line\-buffered, you could |
1084 | readable, but only once. Since it is likely line\-buffered, you could |
879 | attempt to read a whole line in the callback: |
1085 | attempt to read a whole line in the callback. |
880 | .PP |
1086 | .PP |
881 | .Vb 6 |
1087 | .Vb 6 |
882 | \& static void |
1088 | \& static void |
883 | \& stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
1089 | \& stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
884 | \& { |
1090 | \& { |
… | |
… | |
939 | .IP "ev_timer_again (loop)" 4 |
1145 | .IP "ev_timer_again (loop)" 4 |
940 | .IX Item "ev_timer_again (loop)" |
1146 | .IX Item "ev_timer_again (loop)" |
941 | This will act as if the timer timed out and restart it again if it is |
1147 | This will act as if the timer timed out and restart it again if it is |
942 | repeating. The exact semantics are: |
1148 | repeating. The exact semantics are: |
943 | .Sp |
1149 | .Sp |
|
|
1150 | If the timer is pending, its pending status is cleared. |
|
|
1151 | .Sp |
944 | If the timer is started but nonrepeating, stop it. |
1152 | If the timer is started but nonrepeating, stop it (as if it timed out). |
945 | .Sp |
1153 | .Sp |
946 | If the timer is repeating, either start it if necessary (with the repeat |
1154 | If the timer is repeating, either start it if necessary (with the |
947 | value), or reset the running timer to the repeat value. |
1155 | \&\f(CW\*(C`repeat\*(C'\fR value), or reset the running timer to the \f(CW\*(C`repeat\*(C'\fR value. |
948 | .Sp |
1156 | .Sp |
949 | This sounds a bit complicated, but here is a useful and typical |
1157 | This sounds a bit complicated, but here is a useful and typical |
950 | example: Imagine you have a tcp connection and you want a so-called idle |
1158 | example: Imagine you have a tcp connection and you want a so-called idle |
951 | timeout, that is, you want to be called when there have been, say, 60 |
1159 | timeout, that is, you want to be called when there have been, say, 60 |
952 | seconds of inactivity on the socket. The easiest way to do this is to |
1160 | seconds of inactivity on the socket. The easiest way to do this is to |
953 | configure an \f(CW\*(C`ev_timer\*(C'\fR with after=repeat=60 and calling ev_timer_again each |
1161 | configure an \f(CW\*(C`ev_timer\*(C'\fR with a \f(CW\*(C`repeat\*(C'\fR value of \f(CW60\fR and then call |
954 | time you successfully read or write some data. If you go into an idle |
1162 | \&\f(CW\*(C`ev_timer_again\*(C'\fR each time you successfully read or write some data. If |
955 | state where you do not expect data to travel on the socket, you can stop |
1163 | you go into an idle state where you do not expect data to travel on the |
956 | the timer, and again will automatically restart it if need be. |
1164 | socket, you can \f(CW\*(C`ev_timer_stop\*(C'\fR the timer, and \f(CW\*(C`ev_timer_again\*(C'\fR will |
|
|
1165 | automatically restart it if need be. |
|
|
1166 | .Sp |
|
|
1167 | That means you can ignore the \f(CW\*(C`after\*(C'\fR value and \f(CW\*(C`ev_timer_start\*(C'\fR |
|
|
1168 | altogether and only ever use the \f(CW\*(C`repeat\*(C'\fR value and \f(CW\*(C`ev_timer_again\*(C'\fR: |
|
|
1169 | .Sp |
|
|
1170 | .Vb 8 |
|
|
1171 | \& ev_timer_init (timer, callback, 0., 5.); |
|
|
1172 | \& ev_timer_again (loop, timer); |
|
|
1173 | \& ... |
|
|
1174 | \& timer->again = 17.; |
|
|
1175 | \& ev_timer_again (loop, timer); |
|
|
1176 | \& ... |
|
|
1177 | \& timer->again = 10.; |
|
|
1178 | \& ev_timer_again (loop, timer); |
|
|
1179 | .Ve |
|
|
1180 | .Sp |
|
|
1181 | This is more slightly efficient then stopping/starting the timer each time |
|
|
1182 | you want to modify its timeout value. |
|
|
1183 | .IP "ev_tstamp repeat [read\-write]" 4 |
|
|
1184 | .IX Item "ev_tstamp repeat [read-write]" |
|
|
1185 | The current \f(CW\*(C`repeat\*(C'\fR value. Will be used each time the watcher times out |
|
|
1186 | or \f(CW\*(C`ev_timer_again\*(C'\fR is called and determines the next timeout (if any), |
|
|
1187 | which is also when any modifications are taken into account. |
957 | .PP |
1188 | .PP |
958 | Example: create a timer that fires after 60 seconds. |
1189 | Example: Create a timer that fires after 60 seconds. |
959 | .PP |
1190 | .PP |
960 | .Vb 5 |
1191 | .Vb 5 |
961 | \& static void |
1192 | \& static void |
962 | \& one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1193 | \& one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
963 | \& { |
1194 | \& { |
… | |
… | |
969 | \& struct ev_timer mytimer; |
1200 | \& struct ev_timer mytimer; |
970 | \& ev_timer_init (&mytimer, one_minute_cb, 60., 0.); |
1201 | \& ev_timer_init (&mytimer, one_minute_cb, 60., 0.); |
971 | \& ev_timer_start (loop, &mytimer); |
1202 | \& ev_timer_start (loop, &mytimer); |
972 | .Ve |
1203 | .Ve |
973 | .PP |
1204 | .PP |
974 | Example: create a timeout timer that times out after 10 seconds of |
1205 | Example: Create a timeout timer that times out after 10 seconds of |
975 | inactivity. |
1206 | inactivity. |
976 | .PP |
1207 | .PP |
977 | .Vb 5 |
1208 | .Vb 5 |
978 | \& static void |
1209 | \& static void |
979 | \& timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1210 | \& timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
… | |
… | |
1004 | but on wallclock time (absolute time). You can tell a periodic watcher |
1235 | but on wallclock time (absolute time). You can tell a periodic watcher |
1005 | to trigger \*(L"at\*(R" some specific point in time. For example, if you tell a |
1236 | to trigger \*(L"at\*(R" some specific point in time. For example, if you tell a |
1006 | periodic watcher to trigger in 10 seconds (by specifiying e.g. \f(CW\*(C`ev_now () |
1237 | periodic watcher to trigger in 10 seconds (by specifiying e.g. \f(CW\*(C`ev_now () |
1007 | + 10.\*(C'\fR) and then reset your system clock to the last year, then it will |
1238 | + 10.\*(C'\fR) and then reset your system clock to the last year, then it will |
1008 | take a year to trigger the event (unlike an \f(CW\*(C`ev_timer\*(C'\fR, which would trigger |
1239 | take a year to trigger the event (unlike an \f(CW\*(C`ev_timer\*(C'\fR, which would trigger |
1009 | roughly 10 seconds later and of course not if you reset your system time |
1240 | roughly 10 seconds later). |
1010 | again). |
|
|
1011 | .PP |
1241 | .PP |
1012 | They can also be used to implement vastly more complex timers, such as |
1242 | They can also be used to implement vastly more complex timers, such as |
1013 | triggering an event on eahc midnight, local time. |
1243 | triggering an event on each midnight, local time or other, complicated, |
|
|
1244 | rules. |
1014 | .PP |
1245 | .PP |
1015 | As with timers, the callback is guarenteed to be invoked only when the |
1246 | As with timers, the callback is guarenteed to be invoked only when the |
1016 | time (\f(CW\*(C`at\*(C'\fR) has been passed, but if multiple periodic timers become ready |
1247 | time (\f(CW\*(C`at\*(C'\fR) has been passed, but if multiple periodic timers become ready |
1017 | during the same loop iteration then order of execution is undefined. |
1248 | during the same loop iteration then order of execution is undefined. |
1018 | .IP "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" 4 |
1249 | .IP "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" 4 |
… | |
… | |
1022 | .IX Item "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" |
1253 | .IX Item "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" |
1023 | .PD |
1254 | .PD |
1024 | Lots of arguments, lets sort it out... There are basically three modes of |
1255 | Lots of arguments, lets sort it out... There are basically three modes of |
1025 | operation, and we will explain them from simplest to complex: |
1256 | operation, and we will explain them from simplest to complex: |
1026 | .RS 4 |
1257 | .RS 4 |
1027 | .IP "* absolute timer (interval = reschedule_cb = 0)" 4 |
1258 | .IP "* absolute timer (at = time, interval = reschedule_cb = 0)" 4 |
1028 | .IX Item "absolute timer (interval = reschedule_cb = 0)" |
1259 | .IX Item "absolute timer (at = time, interval = reschedule_cb = 0)" |
1029 | In this configuration the watcher triggers an event at the wallclock time |
1260 | In this configuration the watcher triggers an event at the wallclock time |
1030 | \&\f(CW\*(C`at\*(C'\fR and doesn't repeat. It will not adjust when a time jump occurs, |
1261 | \&\f(CW\*(C`at\*(C'\fR and doesn't repeat. It will not adjust when a time jump occurs, |
1031 | that is, if it is to be run at January 1st 2011 then it will run when the |
1262 | that is, if it is to be run at January 1st 2011 then it will run when the |
1032 | system time reaches or surpasses this time. |
1263 | system time reaches or surpasses this time. |
1033 | .IP "* non-repeating interval timer (interval > 0, reschedule_cb = 0)" 4 |
1264 | .IP "* non-repeating interval timer (at = offset, interval > 0, reschedule_cb = 0)" 4 |
1034 | .IX Item "non-repeating interval timer (interval > 0, reschedule_cb = 0)" |
1265 | .IX Item "non-repeating interval timer (at = offset, interval > 0, reschedule_cb = 0)" |
1035 | In this mode the watcher will always be scheduled to time out at the next |
1266 | In this mode the watcher will always be scheduled to time out at the next |
1036 | \&\f(CW\*(C`at + N * interval\*(C'\fR time (for some integer N) and then repeat, regardless |
1267 | \&\f(CW\*(C`at + N * interval\*(C'\fR time (for some integer N, which can also be negative) |
1037 | of any time jumps. |
1268 | and then repeat, regardless of any time jumps. |
1038 | .Sp |
1269 | .Sp |
1039 | This can be used to create timers that do not drift with respect to system |
1270 | This can be used to create timers that do not drift with respect to system |
1040 | time: |
1271 | time: |
1041 | .Sp |
1272 | .Sp |
1042 | .Vb 1 |
1273 | .Vb 1 |
… | |
… | |
1049 | by 3600. |
1280 | by 3600. |
1050 | .Sp |
1281 | .Sp |
1051 | Another way to think about it (for the mathematically inclined) is that |
1282 | Another way to think about it (for the mathematically inclined) is that |
1052 | \&\f(CW\*(C`ev_periodic\*(C'\fR will try to run the callback in this mode at the next possible |
1283 | \&\f(CW\*(C`ev_periodic\*(C'\fR will try to run the callback in this mode at the next possible |
1053 | time where \f(CW\*(C`time = at (mod interval)\*(C'\fR, regardless of any time jumps. |
1284 | time where \f(CW\*(C`time = at (mod interval)\*(C'\fR, regardless of any time jumps. |
|
|
1285 | .Sp |
|
|
1286 | For numerical stability it is preferable that the \f(CW\*(C`at\*(C'\fR value is near |
|
|
1287 | \&\f(CW\*(C`ev_now ()\*(C'\fR (the current time), but there is no range requirement for |
|
|
1288 | this value. |
1054 | .IP "* manual reschedule mode (reschedule_cb = callback)" 4 |
1289 | .IP "* manual reschedule mode (at and interval ignored, reschedule_cb = callback)" 4 |
1055 | .IX Item "manual reschedule mode (reschedule_cb = callback)" |
1290 | .IX Item "manual reschedule mode (at and interval ignored, reschedule_cb = callback)" |
1056 | In this mode the values for \f(CW\*(C`interval\*(C'\fR and \f(CW\*(C`at\*(C'\fR are both being |
1291 | In this mode the values for \f(CW\*(C`interval\*(C'\fR and \f(CW\*(C`at\*(C'\fR are both being |
1057 | ignored. Instead, each time the periodic watcher gets scheduled, the |
1292 | ignored. Instead, each time the periodic watcher gets scheduled, the |
1058 | reschedule callback will be called with the watcher as first, and the |
1293 | reschedule callback will be called with the watcher as first, and the |
1059 | current time as second argument. |
1294 | current time as second argument. |
1060 | .Sp |
1295 | .Sp |
1061 | \&\s-1NOTE:\s0 \fIThis callback \s-1MUST\s0 \s-1NOT\s0 stop or destroy any periodic watcher, |
1296 | \&\s-1NOTE:\s0 \fIThis callback \s-1MUST\s0 \s-1NOT\s0 stop or destroy any periodic watcher, |
1062 | ever, or make any event loop modifications\fR. If you need to stop it, |
1297 | ever, or make any event loop modifications\fR. If you need to stop it, |
1063 | return \f(CW\*(C`now + 1e30\*(C'\fR (or so, fudge fudge) and stop it afterwards (e.g. by |
1298 | return \f(CW\*(C`now + 1e30\*(C'\fR (or so, fudge fudge) and stop it afterwards (e.g. by |
1064 | starting a prepare watcher). |
1299 | starting an \f(CW\*(C`ev_prepare\*(C'\fR watcher, which is legal). |
1065 | .Sp |
1300 | .Sp |
1066 | Its prototype is \f(CW\*(C`ev_tstamp (*reschedule_cb)(struct ev_periodic *w, |
1301 | Its prototype is \f(CW\*(C`ev_tstamp (*reschedule_cb)(struct ev_periodic *w, |
1067 | ev_tstamp now)\*(C'\fR, e.g.: |
1302 | ev_tstamp now)\*(C'\fR, e.g.: |
1068 | .Sp |
1303 | .Sp |
1069 | .Vb 4 |
1304 | .Vb 4 |
… | |
… | |
1093 | .IX Item "ev_periodic_again (loop, ev_periodic *)" |
1328 | .IX Item "ev_periodic_again (loop, ev_periodic *)" |
1094 | Simply stops and restarts the periodic watcher again. This is only useful |
1329 | Simply stops and restarts the periodic watcher again. This is only useful |
1095 | when you changed some parameters or the reschedule callback would return |
1330 | when you changed some parameters or the reschedule callback would return |
1096 | a different time than the last time it was called (e.g. in a crond like |
1331 | a different time than the last time it was called (e.g. in a crond like |
1097 | program when the crontabs have changed). |
1332 | program when the crontabs have changed). |
|
|
1333 | .IP "ev_tstamp offset [read\-write]" 4 |
|
|
1334 | .IX Item "ev_tstamp offset [read-write]" |
|
|
1335 | When repeating, this contains the offset value, otherwise this is the |
|
|
1336 | absolute point in time (the \f(CW\*(C`at\*(C'\fR value passed to \f(CW\*(C`ev_periodic_set\*(C'\fR). |
|
|
1337 | .Sp |
|
|
1338 | Can be modified any time, but changes only take effect when the periodic |
|
|
1339 | timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called. |
|
|
1340 | .IP "ev_tstamp interval [read\-write]" 4 |
|
|
1341 | .IX Item "ev_tstamp interval [read-write]" |
|
|
1342 | The current interval value. Can be modified any time, but changes only |
|
|
1343 | take effect when the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being |
|
|
1344 | called. |
|
|
1345 | .IP "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read\-write]" 4 |
|
|
1346 | .IX Item "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write]" |
|
|
1347 | The current reschedule callback, or \f(CW0\fR, if this functionality is |
|
|
1348 | switched off. Can be changed any time, but changes only take effect when |
|
|
1349 | the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called. |
1098 | .PP |
1350 | .PP |
1099 | Example: call a callback every hour, or, more precisely, whenever the |
1351 | Example: Call a callback every hour, or, more precisely, whenever the |
1100 | system clock is divisible by 3600. The callback invocation times have |
1352 | system clock is divisible by 3600. The callback invocation times have |
1101 | potentially a lot of jittering, but good long-term stability. |
1353 | potentially a lot of jittering, but good long-term stability. |
1102 | .PP |
1354 | .PP |
1103 | .Vb 5 |
1355 | .Vb 5 |
1104 | \& static void |
1356 | \& static void |
… | |
… | |
1112 | \& struct ev_periodic hourly_tick; |
1364 | \& struct ev_periodic hourly_tick; |
1113 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); |
1365 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); |
1114 | \& ev_periodic_start (loop, &hourly_tick); |
1366 | \& ev_periodic_start (loop, &hourly_tick); |
1115 | .Ve |
1367 | .Ve |
1116 | .PP |
1368 | .PP |
1117 | Example: the same as above, but use a reschedule callback to do it: |
1369 | Example: The same as above, but use a reschedule callback to do it: |
1118 | .PP |
1370 | .PP |
1119 | .Vb 1 |
1371 | .Vb 1 |
1120 | \& #include <math.h> |
1372 | \& #include <math.h> |
1121 | .Ve |
1373 | .Ve |
1122 | .PP |
1374 | .PP |
… | |
… | |
1130 | .PP |
1382 | .PP |
1131 | .Vb 1 |
1383 | .Vb 1 |
1132 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); |
1384 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); |
1133 | .Ve |
1385 | .Ve |
1134 | .PP |
1386 | .PP |
1135 | Example: call a callback every hour, starting now: |
1387 | Example: Call a callback every hour, starting now: |
1136 | .PP |
1388 | .PP |
1137 | .Vb 4 |
1389 | .Vb 4 |
1138 | \& struct ev_periodic hourly_tick; |
1390 | \& struct ev_periodic hourly_tick; |
1139 | \& ev_periodic_init (&hourly_tick, clock_cb, |
1391 | \& ev_periodic_init (&hourly_tick, clock_cb, |
1140 | \& fmod (ev_now (loop), 3600.), 3600., 0); |
1392 | \& fmod (ev_now (loop), 3600.), 3600., 0); |
… | |
… | |
1160 | .IP "ev_signal_set (ev_signal *, int signum)" 4 |
1412 | .IP "ev_signal_set (ev_signal *, int signum)" 4 |
1161 | .IX Item "ev_signal_set (ev_signal *, int signum)" |
1413 | .IX Item "ev_signal_set (ev_signal *, int signum)" |
1162 | .PD |
1414 | .PD |
1163 | Configures the watcher to trigger on the given signal number (usually one |
1415 | Configures the watcher to trigger on the given signal number (usually one |
1164 | of the \f(CW\*(C`SIGxxx\*(C'\fR constants). |
1416 | of the \f(CW\*(C`SIGxxx\*(C'\fR constants). |
|
|
1417 | .IP "int signum [read\-only]" 4 |
|
|
1418 | .IX Item "int signum [read-only]" |
|
|
1419 | The signal the watcher watches out for. |
1165 | .ie n .Sh """ev_child"" \- watch out for process status changes" |
1420 | .ie n .Sh """ev_child"" \- watch out for process status changes" |
1166 | .el .Sh "\f(CWev_child\fP \- watch out for process status changes" |
1421 | .el .Sh "\f(CWev_child\fP \- watch out for process status changes" |
1167 | .IX Subsection "ev_child - watch out for process status changes" |
1422 | .IX Subsection "ev_child - watch out for process status changes" |
1168 | Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to |
1423 | Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to |
1169 | some child status changes (most typically when a child of yours dies). |
1424 | some child status changes (most typically when a child of yours dies). |
… | |
… | |
1177 | \&\fIany\fR process if \f(CW\*(C`pid\*(C'\fR is specified as \f(CW0\fR). The callback can look |
1432 | \&\fIany\fR process if \f(CW\*(C`pid\*(C'\fR is specified as \f(CW0\fR). The callback can look |
1178 | at the \f(CW\*(C`rstatus\*(C'\fR member of the \f(CW\*(C`ev_child\*(C'\fR watcher structure to see |
1433 | at the \f(CW\*(C`rstatus\*(C'\fR member of the \f(CW\*(C`ev_child\*(C'\fR watcher structure to see |
1179 | the status word (use the macros from \f(CW\*(C`sys/wait.h\*(C'\fR and see your systems |
1434 | the status word (use the macros from \f(CW\*(C`sys/wait.h\*(C'\fR and see your systems |
1180 | \&\f(CW\*(C`waitpid\*(C'\fR documentation). The \f(CW\*(C`rpid\*(C'\fR member contains the pid of the |
1435 | \&\f(CW\*(C`waitpid\*(C'\fR documentation). The \f(CW\*(C`rpid\*(C'\fR member contains the pid of the |
1181 | process causing the status change. |
1436 | process causing the status change. |
|
|
1437 | .IP "int pid [read\-only]" 4 |
|
|
1438 | .IX Item "int pid [read-only]" |
|
|
1439 | The process id this watcher watches out for, or \f(CW0\fR, meaning any process id. |
|
|
1440 | .IP "int rpid [read\-write]" 4 |
|
|
1441 | .IX Item "int rpid [read-write]" |
|
|
1442 | The process id that detected a status change. |
|
|
1443 | .IP "int rstatus [read\-write]" 4 |
|
|
1444 | .IX Item "int rstatus [read-write]" |
|
|
1445 | The process exit/trace status caused by \f(CW\*(C`rpid\*(C'\fR (see your systems |
|
|
1446 | \&\f(CW\*(C`waitpid\*(C'\fR and \f(CW\*(C`sys/wait.h\*(C'\fR documentation for details). |
1182 | .PP |
1447 | .PP |
1183 | Example: try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0. |
1448 | Example: Try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0. |
1184 | .PP |
1449 | .PP |
1185 | .Vb 5 |
1450 | .Vb 5 |
1186 | \& static void |
1451 | \& static void |
1187 | \& sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
1452 | \& sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
1188 | \& { |
1453 | \& { |
… | |
… | |
1193 | .Vb 3 |
1458 | .Vb 3 |
1194 | \& struct ev_signal signal_watcher; |
1459 | \& struct ev_signal signal_watcher; |
1195 | \& ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
1460 | \& ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
1196 | \& ev_signal_start (loop, &sigint_cb); |
1461 | \& ev_signal_start (loop, &sigint_cb); |
1197 | .Ve |
1462 | .Ve |
|
|
1463 | .ie n .Sh """ev_stat"" \- did the file attributes just change?" |
|
|
1464 | .el .Sh "\f(CWev_stat\fP \- did the file attributes just change?" |
|
|
1465 | .IX Subsection "ev_stat - did the file attributes just change?" |
|
|
1466 | This watches a filesystem path for attribute changes. That is, it calls |
|
|
1467 | \&\f(CW\*(C`stat\*(C'\fR regularly (or when the \s-1OS\s0 says it changed) and sees if it changed |
|
|
1468 | compared to the last time, invoking the callback if it did. |
|
|
1469 | .PP |
|
|
1470 | The path does not need to exist: changing from \*(L"path exists\*(R" to \*(L"path does |
|
|
1471 | not exist\*(R" is a status change like any other. The condition \*(L"path does |
|
|
1472 | not exist\*(R" is signified by the \f(CW\*(C`st_nlink\*(C'\fR field being zero (which is |
|
|
1473 | otherwise always forced to be at least one) and all the other fields of |
|
|
1474 | the stat buffer having unspecified contents. |
|
|
1475 | .PP |
|
|
1476 | The path \fIshould\fR be absolute and \fImust not\fR end in a slash. If it is |
|
|
1477 | relative and your working directory changes, the behaviour is undefined. |
|
|
1478 | .PP |
|
|
1479 | Since there is no standard to do this, the portable implementation simply |
|
|
1480 | calls \f(CW\*(C`stat (2)\*(C'\fR regularly on the path to see if it changed somehow. You |
|
|
1481 | can specify a recommended polling interval for this case. If you specify |
|
|
1482 | a polling interval of \f(CW0\fR (highly recommended!) then a \fIsuitable, |
|
|
1483 | unspecified default\fR value will be used (which you can expect to be around |
|
|
1484 | five seconds, although this might change dynamically). Libev will also |
|
|
1485 | impose a minimum interval which is currently around \f(CW0.1\fR, but thats |
|
|
1486 | usually overkill. |
|
|
1487 | .PP |
|
|
1488 | This watcher type is not meant for massive numbers of stat watchers, |
|
|
1489 | as even with OS-supported change notifications, this can be |
|
|
1490 | resource\-intensive. |
|
|
1491 | .PP |
|
|
1492 | At the time of this writing, only the Linux inotify interface is |
|
|
1493 | implemented (implementing kqueue support is left as an exercise for the |
|
|
1494 | reader). Inotify will be used to give hints only and should not change the |
|
|
1495 | semantics of \f(CW\*(C`ev_stat\*(C'\fR watchers, which means that libev sometimes needs |
|
|
1496 | to fall back to regular polling again even with inotify, but changes are |
|
|
1497 | usually detected immediately, and if the file exists there will be no |
|
|
1498 | polling. |
|
|
1499 | .IP "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" 4 |
|
|
1500 | .IX Item "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" |
|
|
1501 | .PD 0 |
|
|
1502 | .IP "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" 4 |
|
|
1503 | .IX Item "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" |
|
|
1504 | .PD |
|
|
1505 | Configures the watcher to wait for status changes of the given |
|
|
1506 | \&\f(CW\*(C`path\*(C'\fR. The \f(CW\*(C`interval\*(C'\fR is a hint on how quickly a change is expected to |
|
|
1507 | be detected and should normally be specified as \f(CW0\fR to let libev choose |
|
|
1508 | a suitable value. The memory pointed to by \f(CW\*(C`path\*(C'\fR must point to the same |
|
|
1509 | path for as long as the watcher is active. |
|
|
1510 | .Sp |
|
|
1511 | The callback will be receive \f(CW\*(C`EV_STAT\*(C'\fR when a change was detected, |
|
|
1512 | relative to the attributes at the time the watcher was started (or the |
|
|
1513 | last change was detected). |
|
|
1514 | .IP "ev_stat_stat (ev_stat *)" 4 |
|
|
1515 | .IX Item "ev_stat_stat (ev_stat *)" |
|
|
1516 | Updates the stat buffer immediately with new values. If you change the |
|
|
1517 | watched path in your callback, you could call this fucntion to avoid |
|
|
1518 | detecting this change (while introducing a race condition). Can also be |
|
|
1519 | useful simply to find out the new values. |
|
|
1520 | .IP "ev_statdata attr [read\-only]" 4 |
|
|
1521 | .IX Item "ev_statdata attr [read-only]" |
|
|
1522 | The most-recently detected attributes of the file. Although the type is of |
|
|
1523 | \&\f(CW\*(C`ev_statdata\*(C'\fR, this is usually the (or one of the) \f(CW\*(C`struct stat\*(C'\fR types |
|
|
1524 | suitable for your system. If the \f(CW\*(C`st_nlink\*(C'\fR member is \f(CW0\fR, then there |
|
|
1525 | was some error while \f(CW\*(C`stat\*(C'\fRing the file. |
|
|
1526 | .IP "ev_statdata prev [read\-only]" 4 |
|
|
1527 | .IX Item "ev_statdata prev [read-only]" |
|
|
1528 | The previous attributes of the file. The callback gets invoked whenever |
|
|
1529 | \&\f(CW\*(C`prev\*(C'\fR != \f(CW\*(C`attr\*(C'\fR. |
|
|
1530 | .IP "ev_tstamp interval [read\-only]" 4 |
|
|
1531 | .IX Item "ev_tstamp interval [read-only]" |
|
|
1532 | The specified interval. |
|
|
1533 | .IP "const char *path [read\-only]" 4 |
|
|
1534 | .IX Item "const char *path [read-only]" |
|
|
1535 | The filesystem path that is being watched. |
|
|
1536 | .PP |
|
|
1537 | Example: Watch \f(CW\*(C`/etc/passwd\*(C'\fR for attribute changes. |
|
|
1538 | .PP |
|
|
1539 | .Vb 15 |
|
|
1540 | \& static void |
|
|
1541 | \& passwd_cb (struct ev_loop *loop, ev_stat *w, int revents) |
|
|
1542 | \& { |
|
|
1543 | \& /* /etc/passwd changed in some way */ |
|
|
1544 | \& if (w->attr.st_nlink) |
|
|
1545 | \& { |
|
|
1546 | \& printf ("passwd current size %ld\en", (long)w->attr.st_size); |
|
|
1547 | \& printf ("passwd current atime %ld\en", (long)w->attr.st_mtime); |
|
|
1548 | \& printf ("passwd current mtime %ld\en", (long)w->attr.st_mtime); |
|
|
1549 | \& } |
|
|
1550 | \& else |
|
|
1551 | \& /* you shalt not abuse printf for puts */ |
|
|
1552 | \& puts ("wow, /etc/passwd is not there, expect problems. " |
|
|
1553 | \& "if this is windows, they already arrived\en"); |
|
|
1554 | \& } |
|
|
1555 | .Ve |
|
|
1556 | .PP |
|
|
1557 | .Vb 2 |
|
|
1558 | \& ... |
|
|
1559 | \& ev_stat passwd; |
|
|
1560 | .Ve |
|
|
1561 | .PP |
|
|
1562 | .Vb 2 |
|
|
1563 | \& ev_stat_init (&passwd, passwd_cb, "/etc/passwd"); |
|
|
1564 | \& ev_stat_start (loop, &passwd); |
|
|
1565 | .Ve |
1198 | .ie n .Sh """ev_idle"" \- when you've got nothing better to do..." |
1566 | .ie n .Sh """ev_idle"" \- when you've got nothing better to do..." |
1199 | .el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do..." |
1567 | .el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do..." |
1200 | .IX Subsection "ev_idle - when you've got nothing better to do..." |
1568 | .IX Subsection "ev_idle - when you've got nothing better to do..." |
1201 | Idle watchers trigger events when there are no other events are pending |
1569 | Idle watchers trigger events when no other events of the same or higher |
1202 | (prepare, check and other idle watchers do not count). That is, as long |
1570 | priority are pending (prepare, check and other idle watchers do not |
1203 | as your process is busy handling sockets or timeouts (or even signals, |
1571 | count). |
1204 | imagine) it will not be triggered. But when your process is idle all idle |
1572 | .PP |
1205 | watchers are being called again and again, once per event loop iteration \- |
1573 | That is, as long as your process is busy handling sockets or timeouts |
|
|
1574 | (or even signals, imagine) of the same or higher priority it will not be |
|
|
1575 | triggered. But when your process is idle (or only lower-priority watchers |
|
|
1576 | are pending), the idle watchers are being called once per event loop |
1206 | until stopped, that is, or your process receives more events and becomes |
1577 | iteration \- until stopped, that is, or your process receives more events |
1207 | busy. |
1578 | and becomes busy again with higher priority stuff. |
1208 | .PP |
1579 | .PP |
1209 | The most noteworthy effect is that as long as any idle watchers are |
1580 | The most noteworthy effect is that as long as any idle watchers are |
1210 | active, the process will not block when waiting for new events. |
1581 | active, the process will not block when waiting for new events. |
1211 | .PP |
1582 | .PP |
1212 | Apart from keeping your process non-blocking (which is a useful |
1583 | Apart from keeping your process non-blocking (which is a useful |
… | |
… | |
1217 | .IX Item "ev_idle_init (ev_signal *, callback)" |
1588 | .IX Item "ev_idle_init (ev_signal *, callback)" |
1218 | Initialises and configures the idle watcher \- it has no parameters of any |
1589 | Initialises and configures the idle watcher \- it has no parameters of any |
1219 | kind. There is a \f(CW\*(C`ev_idle_set\*(C'\fR macro, but using it is utterly pointless, |
1590 | kind. There is a \f(CW\*(C`ev_idle_set\*(C'\fR macro, but using it is utterly pointless, |
1220 | believe me. |
1591 | believe me. |
1221 | .PP |
1592 | .PP |
1222 | Example: dynamically allocate an \f(CW\*(C`ev_idle\*(C'\fR, start it, and in the |
1593 | Example: Dynamically allocate an \f(CW\*(C`ev_idle\*(C'\fR watcher, start it, and in the |
1223 | callback, free it. Alos, use no error checking, as usual. |
1594 | callback, free it. Also, use no error checking, as usual. |
1224 | .PP |
1595 | .PP |
1225 | .Vb 7 |
1596 | .Vb 7 |
1226 | \& static void |
1597 | \& static void |
1227 | \& idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
1598 | \& idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
1228 | \& { |
1599 | \& { |
… | |
… | |
1275 | are ready to run (it's actually more complicated: it only runs coroutines |
1646 | are ready to run (it's actually more complicated: it only runs coroutines |
1276 | with priority higher than or equal to the event loop and one coroutine |
1647 | with priority higher than or equal to the event loop and one coroutine |
1277 | of lower priority, but only once, using idle watchers to keep the event |
1648 | of lower priority, but only once, using idle watchers to keep the event |
1278 | loop from blocking if lower-priority coroutines are active, thus mapping |
1649 | loop from blocking if lower-priority coroutines are active, thus mapping |
1279 | low-priority coroutines to idle/background tasks). |
1650 | low-priority coroutines to idle/background tasks). |
|
|
1651 | .PP |
|
|
1652 | It is recommended to give \f(CW\*(C`ev_check\*(C'\fR watchers highest (\f(CW\*(C`EV_MAXPRI\*(C'\fR) |
|
|
1653 | priority, to ensure that they are being run before any other watchers |
|
|
1654 | after the poll. Also, \f(CW\*(C`ev_check\*(C'\fR watchers (and \f(CW\*(C`ev_prepare\*(C'\fR watchers, |
|
|
1655 | too) should not activate (\*(L"feed\*(R") events into libev. While libev fully |
|
|
1656 | supports this, they will be called before other \f(CW\*(C`ev_check\*(C'\fR watchers did |
|
|
1657 | their job. As \f(CW\*(C`ev_check\*(C'\fR watchers are often used to embed other event |
|
|
1658 | loops those other event loops might be in an unusable state until their |
|
|
1659 | \&\f(CW\*(C`ev_check\*(C'\fR watcher ran (always remind yourself to coexist peacefully with |
|
|
1660 | others). |
1280 | .IP "ev_prepare_init (ev_prepare *, callback)" 4 |
1661 | .IP "ev_prepare_init (ev_prepare *, callback)" 4 |
1281 | .IX Item "ev_prepare_init (ev_prepare *, callback)" |
1662 | .IX Item "ev_prepare_init (ev_prepare *, callback)" |
1282 | .PD 0 |
1663 | .PD 0 |
1283 | .IP "ev_check_init (ev_check *, callback)" 4 |
1664 | .IP "ev_check_init (ev_check *, callback)" 4 |
1284 | .IX Item "ev_check_init (ev_check *, callback)" |
1665 | .IX Item "ev_check_init (ev_check *, callback)" |
1285 | .PD |
1666 | .PD |
1286 | Initialises and configures the prepare or check watcher \- they have no |
1667 | Initialises and configures the prepare or check watcher \- they have no |
1287 | parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR |
1668 | parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR |
1288 | macros, but using them is utterly, utterly and completely pointless. |
1669 | macros, but using them is utterly, utterly and completely pointless. |
1289 | .PP |
1670 | .PP |
1290 | Example: To include a library such as adns, you would add \s-1IO\s0 watchers |
1671 | There are a number of principal ways to embed other event loops or modules |
1291 | and a timeout watcher in a prepare handler, as required by libadns, and |
1672 | into libev. Here are some ideas on how to include libadns into libev |
|
|
1673 | (there is a Perl module named \f(CW\*(C`EV::ADNS\*(C'\fR that does this, which you could |
|
|
1674 | use for an actually working example. Another Perl module named \f(CW\*(C`EV::Glib\*(C'\fR |
|
|
1675 | embeds a Glib main context into libev, and finally, \f(CW\*(C`Glib::EV\*(C'\fR embeds \s-1EV\s0 |
|
|
1676 | into the Glib event loop). |
|
|
1677 | .PP |
|
|
1678 | Method 1: Add \s-1IO\s0 watchers and a timeout watcher in a prepare handler, |
1292 | in a check watcher, destroy them and call into libadns. What follows is |
1679 | and in a check watcher, destroy them and call into libadns. What follows |
1293 | pseudo-code only of course: |
1680 | is pseudo-code only of course. This requires you to either use a low |
|
|
1681 | priority for the check watcher or use \f(CW\*(C`ev_clear_pending\*(C'\fR explicitly, as |
|
|
1682 | the callbacks for the IO/timeout watchers might not have been called yet. |
1294 | .PP |
1683 | .PP |
1295 | .Vb 2 |
1684 | .Vb 2 |
1296 | \& static ev_io iow [nfd]; |
1685 | \& static ev_io iow [nfd]; |
1297 | \& static ev_timer tw; |
1686 | \& static ev_timer tw; |
1298 | .Ve |
1687 | .Ve |
1299 | .PP |
1688 | .PP |
1300 | .Vb 8 |
1689 | .Vb 4 |
1301 | \& static void |
1690 | \& static void |
1302 | \& io_cb (ev_loop *loop, ev_io *w, int revents) |
1691 | \& io_cb (ev_loop *loop, ev_io *w, int revents) |
1303 | \& { |
1692 | \& { |
1304 | \& // set the relevant poll flags |
|
|
1305 | \& struct pollfd *fd = (struct pollfd *)w->data; |
|
|
1306 | \& if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
|
|
1307 | \& if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
|
|
1308 | \& } |
1693 | \& } |
1309 | .Ve |
1694 | .Ve |
1310 | .PP |
1695 | .PP |
1311 | .Vb 7 |
1696 | .Vb 8 |
1312 | \& // create io watchers for each fd and a timer before blocking |
1697 | \& // create io watchers for each fd and a timer before blocking |
1313 | \& static void |
1698 | \& static void |
1314 | \& adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
1699 | \& adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
1315 | \& { |
1700 | \& { |
1316 | \& int timeout = 3600000;truct pollfd fds [nfd]; |
1701 | \& int timeout = 3600000; |
|
|
1702 | \& struct pollfd fds [nfd]; |
1317 | \& // actual code will need to loop here and realloc etc. |
1703 | \& // actual code will need to loop here and realloc etc. |
1318 | \& adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
1704 | \& adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
1319 | .Ve |
1705 | .Ve |
1320 | .PP |
1706 | .PP |
1321 | .Vb 3 |
1707 | .Vb 3 |
… | |
… | |
1323 | \& ev_timer_init (&tw, 0, timeout * 1e-3); |
1709 | \& ev_timer_init (&tw, 0, timeout * 1e-3); |
1324 | \& ev_timer_start (loop, &tw); |
1710 | \& ev_timer_start (loop, &tw); |
1325 | .Ve |
1711 | .Ve |
1326 | .PP |
1712 | .PP |
1327 | .Vb 6 |
1713 | .Vb 6 |
1328 | \& // create on ev_io per pollfd |
1714 | \& // create one ev_io per pollfd |
1329 | \& for (int i = 0; i < nfd; ++i) |
1715 | \& for (int i = 0; i < nfd; ++i) |
1330 | \& { |
1716 | \& { |
1331 | \& ev_io_init (iow + i, io_cb, fds [i].fd, |
1717 | \& ev_io_init (iow + i, io_cb, fds [i].fd, |
1332 | \& ((fds [i].events & POLLIN ? EV_READ : 0) |
1718 | \& ((fds [i].events & POLLIN ? EV_READ : 0) |
1333 | \& | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
1719 | \& | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
1334 | .Ve |
1720 | .Ve |
1335 | .PP |
1721 | .PP |
1336 | .Vb 5 |
1722 | .Vb 4 |
1337 | \& fds [i].revents = 0; |
1723 | \& fds [i].revents = 0; |
1338 | \& iow [i].data = fds + i; |
|
|
1339 | \& ev_io_start (loop, iow + i); |
1724 | \& ev_io_start (loop, iow + i); |
1340 | \& } |
1725 | \& } |
1341 | \& } |
1726 | \& } |
1342 | .Ve |
1727 | .Ve |
1343 | .PP |
1728 | .PP |
… | |
… | |
1347 | \& adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
1732 | \& adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
1348 | \& { |
1733 | \& { |
1349 | \& ev_timer_stop (loop, &tw); |
1734 | \& ev_timer_stop (loop, &tw); |
1350 | .Ve |
1735 | .Ve |
1351 | .PP |
1736 | .PP |
1352 | .Vb 2 |
1737 | .Vb 8 |
1353 | \& for (int i = 0; i < nfd; ++i) |
1738 | \& for (int i = 0; i < nfd; ++i) |
|
|
1739 | \& { |
|
|
1740 | \& // set the relevant poll flags |
|
|
1741 | \& // could also call adns_processreadable etc. here |
|
|
1742 | \& struct pollfd *fd = fds + i; |
|
|
1743 | \& int revents = ev_clear_pending (iow + i); |
|
|
1744 | \& if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
|
|
1745 | \& if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
|
|
1746 | .Ve |
|
|
1747 | .PP |
|
|
1748 | .Vb 3 |
|
|
1749 | \& // now stop the watcher |
1354 | \& ev_io_stop (loop, iow + i); |
1750 | \& ev_io_stop (loop, iow + i); |
|
|
1751 | \& } |
1355 | .Ve |
1752 | .Ve |
1356 | .PP |
1753 | .PP |
1357 | .Vb 2 |
1754 | .Vb 2 |
1358 | \& adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
1755 | \& adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
|
|
1756 | \& } |
|
|
1757 | .Ve |
|
|
1758 | .PP |
|
|
1759 | Method 2: This would be just like method 1, but you run \f(CW\*(C`adns_afterpoll\*(C'\fR |
|
|
1760 | in the prepare watcher and would dispose of the check watcher. |
|
|
1761 | .PP |
|
|
1762 | Method 3: If the module to be embedded supports explicit event |
|
|
1763 | notification (adns does), you can also make use of the actual watcher |
|
|
1764 | callbacks, and only destroy/create the watchers in the prepare watcher. |
|
|
1765 | .PP |
|
|
1766 | .Vb 5 |
|
|
1767 | \& static void |
|
|
1768 | \& timer_cb (EV_P_ ev_timer *w, int revents) |
|
|
1769 | \& { |
|
|
1770 | \& adns_state ads = (adns_state)w->data; |
|
|
1771 | \& update_now (EV_A); |
|
|
1772 | .Ve |
|
|
1773 | .PP |
|
|
1774 | .Vb 2 |
|
|
1775 | \& adns_processtimeouts (ads, &tv_now); |
|
|
1776 | \& } |
|
|
1777 | .Ve |
|
|
1778 | .PP |
|
|
1779 | .Vb 5 |
|
|
1780 | \& static void |
|
|
1781 | \& io_cb (EV_P_ ev_io *w, int revents) |
|
|
1782 | \& { |
|
|
1783 | \& adns_state ads = (adns_state)w->data; |
|
|
1784 | \& update_now (EV_A); |
|
|
1785 | .Ve |
|
|
1786 | .PP |
|
|
1787 | .Vb 3 |
|
|
1788 | \& if (revents & EV_READ ) adns_processreadable (ads, w->fd, &tv_now); |
|
|
1789 | \& if (revents & EV_WRITE) adns_processwriteable (ads, w->fd, &tv_now); |
|
|
1790 | \& } |
|
|
1791 | .Ve |
|
|
1792 | .PP |
|
|
1793 | .Vb 1 |
|
|
1794 | \& // do not ever call adns_afterpoll |
|
|
1795 | .Ve |
|
|
1796 | .PP |
|
|
1797 | Method 4: Do not use a prepare or check watcher because the module you |
|
|
1798 | want to embed is too inflexible to support it. Instead, youc na override |
|
|
1799 | their poll function. The drawback with this solution is that the main |
|
|
1800 | loop is now no longer controllable by \s-1EV\s0. The \f(CW\*(C`Glib::EV\*(C'\fR module does |
|
|
1801 | this. |
|
|
1802 | .PP |
|
|
1803 | .Vb 4 |
|
|
1804 | \& static gint |
|
|
1805 | \& event_poll_func (GPollFD *fds, guint nfds, gint timeout) |
|
|
1806 | \& { |
|
|
1807 | \& int got_events = 0; |
|
|
1808 | .Ve |
|
|
1809 | .PP |
|
|
1810 | .Vb 2 |
|
|
1811 | \& for (n = 0; n < nfds; ++n) |
|
|
1812 | \& // create/start io watcher that sets the relevant bits in fds[n] and increment got_events |
|
|
1813 | .Ve |
|
|
1814 | .PP |
|
|
1815 | .Vb 2 |
|
|
1816 | \& if (timeout >= 0) |
|
|
1817 | \& // create/start timer |
|
|
1818 | .Ve |
|
|
1819 | .PP |
|
|
1820 | .Vb 2 |
|
|
1821 | \& // poll |
|
|
1822 | \& ev_loop (EV_A_ 0); |
|
|
1823 | .Ve |
|
|
1824 | .PP |
|
|
1825 | .Vb 3 |
|
|
1826 | \& // stop timer again |
|
|
1827 | \& if (timeout >= 0) |
|
|
1828 | \& ev_timer_stop (EV_A_ &to); |
|
|
1829 | .Ve |
|
|
1830 | .PP |
|
|
1831 | .Vb 3 |
|
|
1832 | \& // stop io watchers again - their callbacks should have set |
|
|
1833 | \& for (n = 0; n < nfds; ++n) |
|
|
1834 | \& ev_io_stop (EV_A_ iow [n]); |
|
|
1835 | .Ve |
|
|
1836 | .PP |
|
|
1837 | .Vb 2 |
|
|
1838 | \& return got_events; |
1359 | \& } |
1839 | \& } |
1360 | .Ve |
1840 | .Ve |
1361 | .ie n .Sh """ev_embed"" \- when one backend isn't enough..." |
1841 | .ie n .Sh """ev_embed"" \- when one backend isn't enough..." |
1362 | .el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..." |
1842 | .el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..." |
1363 | .IX Subsection "ev_embed - when one backend isn't enough..." |
1843 | .IX Subsection "ev_embed - when one backend isn't enough..." |
… | |
… | |
1448 | .IP "ev_embed_sweep (loop, ev_embed *)" 4 |
1928 | .IP "ev_embed_sweep (loop, ev_embed *)" 4 |
1449 | .IX Item "ev_embed_sweep (loop, ev_embed *)" |
1929 | .IX Item "ev_embed_sweep (loop, ev_embed *)" |
1450 | Make a single, non-blocking sweep over the embedded loop. This works |
1930 | Make a single, non-blocking sweep over the embedded loop. This works |
1451 | similarly to \f(CW\*(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\*(C'\fR, but in the most |
1931 | similarly to \f(CW\*(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\*(C'\fR, but in the most |
1452 | apropriate way for embedded loops. |
1932 | apropriate way for embedded loops. |
|
|
1933 | .IP "struct ev_loop *loop [read\-only]" 4 |
|
|
1934 | .IX Item "struct ev_loop *loop [read-only]" |
|
|
1935 | The embedded event loop. |
|
|
1936 | .ie n .Sh """ev_fork"" \- the audacity to resume the event loop after a fork" |
|
|
1937 | .el .Sh "\f(CWev_fork\fP \- the audacity to resume the event loop after a fork" |
|
|
1938 | .IX Subsection "ev_fork - the audacity to resume the event loop after a fork" |
|
|
1939 | Fork watchers are called when a \f(CW\*(C`fork ()\*(C'\fR was detected (usually because |
|
|
1940 | whoever is a good citizen cared to tell libev about it by calling |
|
|
1941 | \&\f(CW\*(C`ev_default_fork\*(C'\fR or \f(CW\*(C`ev_loop_fork\*(C'\fR). The invocation is done before the |
|
|
1942 | event loop blocks next and before \f(CW\*(C`ev_check\*(C'\fR watchers are being called, |
|
|
1943 | and only in the child after the fork. If whoever good citizen calling |
|
|
1944 | \&\f(CW\*(C`ev_default_fork\*(C'\fR cheats and calls it in the wrong process, the fork |
|
|
1945 | handlers will be invoked, too, of course. |
|
|
1946 | .IP "ev_fork_init (ev_signal *, callback)" 4 |
|
|
1947 | .IX Item "ev_fork_init (ev_signal *, callback)" |
|
|
1948 | Initialises and configures the fork watcher \- it has no parameters of any |
|
|
1949 | kind. There is a \f(CW\*(C`ev_fork_set\*(C'\fR macro, but using it is utterly pointless, |
|
|
1950 | believe me. |
1453 | .SH "OTHER FUNCTIONS" |
1951 | .SH "OTHER FUNCTIONS" |
1454 | .IX Header "OTHER FUNCTIONS" |
1952 | .IX Header "OTHER FUNCTIONS" |
1455 | There are some other functions of possible interest. Described. Here. Now. |
1953 | There are some other functions of possible interest. Described. Here. Now. |
1456 | .IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4 |
1954 | .IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4 |
1457 | .IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" |
1955 | .IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" |
… | |
… | |
1529 | .PP |
2027 | .PP |
1530 | .Vb 1 |
2028 | .Vb 1 |
1531 | \& #include <ev++.h> |
2029 | \& #include <ev++.h> |
1532 | .Ve |
2030 | .Ve |
1533 | .PP |
2031 | .PP |
1534 | (it is not installed by default). This automatically includes \fIev.h\fR |
2032 | This automatically includes \fIev.h\fR and puts all of its definitions (many |
1535 | and puts all of its definitions (many of them macros) into the global |
2033 | of them macros) into the global namespace. All \*(C+ specific things are |
1536 | namespace. All \*(C+ specific things are put into the \f(CW\*(C`ev\*(C'\fR namespace. |
2034 | put into the \f(CW\*(C`ev\*(C'\fR namespace. It should support all the same embedding |
|
|
2035 | options as \fIev.h\fR, most notably \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. |
1537 | .PP |
2036 | .PP |
1538 | It should support all the same embedding options as \fIev.h\fR, most notably |
2037 | Care has been taken to keep the overhead low. The only data member the \*(C+ |
1539 | \&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. |
2038 | classes add (compared to plain C\-style watchers) is the event loop pointer |
|
|
2039 | that the watcher is associated with (or no additional members at all if |
|
|
2040 | you disable \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR when embedding libev). |
|
|
2041 | .PP |
|
|
2042 | Currently, functions, and static and non-static member functions can be |
|
|
2043 | used as callbacks. Other types should be easy to add as long as they only |
|
|
2044 | need one additional pointer for context. If you need support for other |
|
|
2045 | types of functors please contact the author (preferably after implementing |
|
|
2046 | it). |
1540 | .PP |
2047 | .PP |
1541 | Here is a list of things available in the \f(CW\*(C`ev\*(C'\fR namespace: |
2048 | Here is a list of things available in the \f(CW\*(C`ev\*(C'\fR namespace: |
1542 | .ie n .IP """ev::READ""\fR, \f(CW""ev::WRITE"" etc." 4 |
2049 | .ie n .IP """ev::READ""\fR, \f(CW""ev::WRITE"" etc." 4 |
1543 | .el .IP "\f(CWev::READ\fR, \f(CWev::WRITE\fR etc." 4 |
2050 | .el .IP "\f(CWev::READ\fR, \f(CWev::WRITE\fR etc." 4 |
1544 | .IX Item "ev::READ, ev::WRITE etc." |
2051 | .IX Item "ev::READ, ev::WRITE etc." |
… | |
… | |
1556 | which is called \f(CW\*(C`ev::sig\*(C'\fR to avoid clashes with the \f(CW\*(C`signal\*(C'\fR macro |
2063 | which is called \f(CW\*(C`ev::sig\*(C'\fR to avoid clashes with the \f(CW\*(C`signal\*(C'\fR macro |
1557 | defines by many implementations. |
2064 | defines by many implementations. |
1558 | .Sp |
2065 | .Sp |
1559 | All of those classes have these methods: |
2066 | All of those classes have these methods: |
1560 | .RS 4 |
2067 | .RS 4 |
1561 | .IP "ev::TYPE::TYPE (object *, object::method *)" 4 |
2068 | .IP "ev::TYPE::TYPE ()" 4 |
1562 | .IX Item "ev::TYPE::TYPE (object *, object::method *)" |
2069 | .IX Item "ev::TYPE::TYPE ()" |
1563 | .PD 0 |
2070 | .PD 0 |
1564 | .IP "ev::TYPE::TYPE (object *, object::method *, struct ev_loop *)" 4 |
2071 | .IP "ev::TYPE::TYPE (struct ev_loop *)" 4 |
1565 | .IX Item "ev::TYPE::TYPE (object *, object::method *, struct ev_loop *)" |
2072 | .IX Item "ev::TYPE::TYPE (struct ev_loop *)" |
1566 | .IP "ev::TYPE::~TYPE" 4 |
2073 | .IP "ev::TYPE::~TYPE" 4 |
1567 | .IX Item "ev::TYPE::~TYPE" |
2074 | .IX Item "ev::TYPE::~TYPE" |
1568 | .PD |
2075 | .PD |
1569 | The constructor takes a pointer to an object and a method pointer to |
2076 | The constructor (optionally) takes an event loop to associate the watcher |
1570 | the event handler callback to call in this class. The constructor calls |
2077 | with. If it is omitted, it will use \f(CW\*(C`EV_DEFAULT\*(C'\fR. |
1571 | \&\f(CW\*(C`ev_init\*(C'\fR for you, which means you have to call the \f(CW\*(C`set\*(C'\fR method |
2078 | .Sp |
1572 | before starting it. If you do not specify a loop then the constructor |
2079 | The constructor calls \f(CW\*(C`ev_init\*(C'\fR for you, which means you have to call the |
1573 | automatically associates the default loop with this watcher. |
2080 | \&\f(CW\*(C`set\*(C'\fR method before starting it. |
|
|
2081 | .Sp |
|
|
2082 | It will not set a callback, however: You have to call the templated \f(CW\*(C`set\*(C'\fR |
|
|
2083 | method to set a callback before you can start the watcher. |
|
|
2084 | .Sp |
|
|
2085 | (The reason why you have to use a method is a limitation in \*(C+ which does |
|
|
2086 | not allow explicit template arguments for constructors). |
1574 | .Sp |
2087 | .Sp |
1575 | The destructor automatically stops the watcher if it is active. |
2088 | The destructor automatically stops the watcher if it is active. |
|
|
2089 | .IP "w\->set<class, &class::method> (object *)" 4 |
|
|
2090 | .IX Item "w->set<class, &class::method> (object *)" |
|
|
2091 | This method sets the callback method to call. The method has to have a |
|
|
2092 | signature of \f(CW\*(C`void (*)(ev_TYPE &, int)\*(C'\fR, it receives the watcher as |
|
|
2093 | first argument and the \f(CW\*(C`revents\*(C'\fR as second. The object must be given as |
|
|
2094 | parameter and is stored in the \f(CW\*(C`data\*(C'\fR member of the watcher. |
|
|
2095 | .Sp |
|
|
2096 | This method synthesizes efficient thunking code to call your method from |
|
|
2097 | the C callback that libev requires. If your compiler can inline your |
|
|
2098 | callback (i.e. it is visible to it at the place of the \f(CW\*(C`set\*(C'\fR call and |
|
|
2099 | your compiler is good :), then the method will be fully inlined into the |
|
|
2100 | thunking function, making it as fast as a direct C callback. |
|
|
2101 | .Sp |
|
|
2102 | Example: simple class declaration and watcher initialisation |
|
|
2103 | .Sp |
|
|
2104 | .Vb 4 |
|
|
2105 | \& struct myclass |
|
|
2106 | \& { |
|
|
2107 | \& void io_cb (ev::io &w, int revents) { } |
|
|
2108 | \& } |
|
|
2109 | .Ve |
|
|
2110 | .Sp |
|
|
2111 | .Vb 3 |
|
|
2112 | \& myclass obj; |
|
|
2113 | \& ev::io iow; |
|
|
2114 | \& iow.set <myclass, &myclass::io_cb> (&obj); |
|
|
2115 | .Ve |
|
|
2116 | .IP "w\->set<function> (void *data = 0)" 4 |
|
|
2117 | .IX Item "w->set<function> (void *data = 0)" |
|
|
2118 | Also sets a callback, but uses a static method or plain function as |
|
|
2119 | callback. The optional \f(CW\*(C`data\*(C'\fR argument will be stored in the watcher's |
|
|
2120 | \&\f(CW\*(C`data\*(C'\fR member and is free for you to use. |
|
|
2121 | .Sp |
|
|
2122 | The prototype of the \f(CW\*(C`function\*(C'\fR must be \f(CW\*(C`void (*)(ev::TYPE &w, int)\*(C'\fR. |
|
|
2123 | .Sp |
|
|
2124 | See the method\-\f(CW\*(C`set\*(C'\fR above for more details. |
|
|
2125 | .Sp |
|
|
2126 | Example: |
|
|
2127 | .Sp |
|
|
2128 | .Vb 2 |
|
|
2129 | \& static void io_cb (ev::io &w, int revents) { } |
|
|
2130 | \& iow.set <io_cb> (); |
|
|
2131 | .Ve |
1576 | .IP "w\->set (struct ev_loop *)" 4 |
2132 | .IP "w\->set (struct ev_loop *)" 4 |
1577 | .IX Item "w->set (struct ev_loop *)" |
2133 | .IX Item "w->set (struct ev_loop *)" |
1578 | Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only |
2134 | Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only |
1579 | do this when the watcher is inactive (and not pending either). |
2135 | do this when the watcher is inactive (and not pending either). |
1580 | .IP "w\->set ([args])" 4 |
2136 | .IP "w\->set ([args])" 4 |
1581 | .IX Item "w->set ([args])" |
2137 | .IX Item "w->set ([args])" |
1582 | Basically the same as \f(CW\*(C`ev_TYPE_set\*(C'\fR, with the same args. Must be |
2138 | Basically the same as \f(CW\*(C`ev_TYPE_set\*(C'\fR, with the same args. Must be |
1583 | called at least once. Unlike the C counterpart, an active watcher gets |
2139 | called at least once. Unlike the C counterpart, an active watcher gets |
1584 | automatically stopped and restarted. |
2140 | automatically stopped and restarted when reconfiguring it with this |
|
|
2141 | method. |
1585 | .IP "w\->start ()" 4 |
2142 | .IP "w\->start ()" 4 |
1586 | .IX Item "w->start ()" |
2143 | .IX Item "w->start ()" |
1587 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument as the |
2144 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument, as the |
1588 | constructor already takes the loop. |
2145 | constructor already stores the event loop. |
1589 | .IP "w\->stop ()" 4 |
2146 | .IP "w\->stop ()" 4 |
1590 | .IX Item "w->stop ()" |
2147 | .IX Item "w->stop ()" |
1591 | Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument. |
2148 | Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument. |
1592 | .ie n .IP "w\->again () ""ev::timer""\fR, \f(CW""ev::periodic"" only" 4 |
2149 | .ie n .IP "w\->again () ""ev::timer""\fR, \f(CW""ev::periodic"" only" 4 |
1593 | .el .IP "w\->again () \f(CWev::timer\fR, \f(CWev::periodic\fR only" 4 |
2150 | .el .IP "w\->again () \f(CWev::timer\fR, \f(CWev::periodic\fR only" 4 |
… | |
… | |
1596 | \&\f(CW\*(C`ev_TYPE_again\*(C'\fR function. |
2153 | \&\f(CW\*(C`ev_TYPE_again\*(C'\fR function. |
1597 | .ie n .IP "w\->sweep () ""ev::embed"" only" 4 |
2154 | .ie n .IP "w\->sweep () ""ev::embed"" only" 4 |
1598 | .el .IP "w\->sweep () \f(CWev::embed\fR only" 4 |
2155 | .el .IP "w\->sweep () \f(CWev::embed\fR only" 4 |
1599 | .IX Item "w->sweep () ev::embed only" |
2156 | .IX Item "w->sweep () ev::embed only" |
1600 | Invokes \f(CW\*(C`ev_embed_sweep\*(C'\fR. |
2157 | Invokes \f(CW\*(C`ev_embed_sweep\*(C'\fR. |
|
|
2158 | .ie n .IP "w\->update () ""ev::stat"" only" 4 |
|
|
2159 | .el .IP "w\->update () \f(CWev::stat\fR only" 4 |
|
|
2160 | .IX Item "w->update () ev::stat only" |
|
|
2161 | Invokes \f(CW\*(C`ev_stat_stat\*(C'\fR. |
1601 | .RE |
2162 | .RE |
1602 | .RS 4 |
2163 | .RS 4 |
1603 | .RE |
2164 | .RE |
1604 | .PP |
2165 | .PP |
1605 | Example: Define a class with an \s-1IO\s0 and idle watcher, start one of them in |
2166 | Example: Define a class with an \s-1IO\s0 and idle watcher, start one of them in |
… | |
… | |
1615 | .Vb 2 |
2176 | .Vb 2 |
1616 | \& myclass (); |
2177 | \& myclass (); |
1617 | \& } |
2178 | \& } |
1618 | .Ve |
2179 | .Ve |
1619 | .PP |
2180 | .PP |
1620 | .Vb 6 |
2181 | .Vb 4 |
1621 | \& myclass::myclass (int fd) |
2182 | \& myclass::myclass (int fd) |
1622 | \& : io (this, &myclass::io_cb), |
|
|
1623 | \& idle (this, &myclass::idle_cb) |
|
|
1624 | \& { |
2183 | \& { |
|
|
2184 | \& io .set <myclass, &myclass::io_cb > (this); |
|
|
2185 | \& idle.set <myclass, &myclass::idle_cb> (this); |
|
|
2186 | .Ve |
|
|
2187 | .PP |
|
|
2188 | .Vb 2 |
1625 | \& io.start (fd, ev::READ); |
2189 | \& io.start (fd, ev::READ); |
1626 | \& } |
2190 | \& } |
|
|
2191 | .Ve |
|
|
2192 | .SH "MACRO MAGIC" |
|
|
2193 | .IX Header "MACRO MAGIC" |
|
|
2194 | Libev can be compiled with a variety of options, the most fundemantal is |
|
|
2195 | \&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines whether (most) functions and |
|
|
2196 | callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument. |
|
|
2197 | .PP |
|
|
2198 | To make it easier to write programs that cope with either variant, the |
|
|
2199 | following macros are defined: |
|
|
2200 | .ie n .IP """EV_A""\fR, \f(CW""EV_A_""" 4 |
|
|
2201 | .el .IP "\f(CWEV_A\fR, \f(CWEV_A_\fR" 4 |
|
|
2202 | .IX Item "EV_A, EV_A_" |
|
|
2203 | This provides the loop \fIargument\fR for functions, if one is required (\*(L"ev |
|
|
2204 | loop argument\*(R"). The \f(CW\*(C`EV_A\*(C'\fR form is used when this is the sole argument, |
|
|
2205 | \&\f(CW\*(C`EV_A_\*(C'\fR is used when other arguments are following. Example: |
|
|
2206 | .Sp |
|
|
2207 | .Vb 3 |
|
|
2208 | \& ev_unref (EV_A); |
|
|
2209 | \& ev_timer_add (EV_A_ watcher); |
|
|
2210 | \& ev_loop (EV_A_ 0); |
|
|
2211 | .Ve |
|
|
2212 | .Sp |
|
|
2213 | It assumes the variable \f(CW\*(C`loop\*(C'\fR of type \f(CW\*(C`struct ev_loop *\*(C'\fR is in scope, |
|
|
2214 | which is often provided by the following macro. |
|
|
2215 | .ie n .IP """EV_P""\fR, \f(CW""EV_P_""" 4 |
|
|
2216 | .el .IP "\f(CWEV_P\fR, \f(CWEV_P_\fR" 4 |
|
|
2217 | .IX Item "EV_P, EV_P_" |
|
|
2218 | This provides the loop \fIparameter\fR for functions, if one is required (\*(L"ev |
|
|
2219 | loop parameter\*(R"). The \f(CW\*(C`EV_P\*(C'\fR form is used when this is the sole parameter, |
|
|
2220 | \&\f(CW\*(C`EV_P_\*(C'\fR is used when other parameters are following. Example: |
|
|
2221 | .Sp |
|
|
2222 | .Vb 2 |
|
|
2223 | \& // this is how ev_unref is being declared |
|
|
2224 | \& static void ev_unref (EV_P); |
|
|
2225 | .Ve |
|
|
2226 | .Sp |
|
|
2227 | .Vb 2 |
|
|
2228 | \& // this is how you can declare your typical callback |
|
|
2229 | \& static void cb (EV_P_ ev_timer *w, int revents) |
|
|
2230 | .Ve |
|
|
2231 | .Sp |
|
|
2232 | It declares a parameter \f(CW\*(C`loop\*(C'\fR of type \f(CW\*(C`struct ev_loop *\*(C'\fR, quite |
|
|
2233 | suitable for use with \f(CW\*(C`EV_A\*(C'\fR. |
|
|
2234 | .ie n .IP """EV_DEFAULT""\fR, \f(CW""EV_DEFAULT_""" 4 |
|
|
2235 | .el .IP "\f(CWEV_DEFAULT\fR, \f(CWEV_DEFAULT_\fR" 4 |
|
|
2236 | .IX Item "EV_DEFAULT, EV_DEFAULT_" |
|
|
2237 | Similar to the other two macros, this gives you the value of the default |
|
|
2238 | loop, if multiple loops are supported (\*(L"ev loop default\*(R"). |
|
|
2239 | .PP |
|
|
2240 | Example: Declare and initialise a check watcher, utilising the above |
|
|
2241 | macros so it will work regardless of whether multiple loops are supported |
|
|
2242 | or not. |
|
|
2243 | .PP |
|
|
2244 | .Vb 5 |
|
|
2245 | \& static void |
|
|
2246 | \& check_cb (EV_P_ ev_timer *w, int revents) |
|
|
2247 | \& { |
|
|
2248 | \& ev_check_stop (EV_A_ w); |
|
|
2249 | \& } |
|
|
2250 | .Ve |
|
|
2251 | .PP |
|
|
2252 | .Vb 4 |
|
|
2253 | \& ev_check check; |
|
|
2254 | \& ev_check_init (&check, check_cb); |
|
|
2255 | \& ev_check_start (EV_DEFAULT_ &check); |
|
|
2256 | \& ev_loop (EV_DEFAULT_ 0); |
1627 | .Ve |
2257 | .Ve |
1628 | .SH "EMBEDDING" |
2258 | .SH "EMBEDDING" |
1629 | .IX Header "EMBEDDING" |
2259 | .IX Header "EMBEDDING" |
1630 | Libev can (and often is) directly embedded into host |
2260 | Libev can (and often is) directly embedded into host |
1631 | applications. Examples of applications that embed it include the Deliantra |
2261 | applications. Examples of applications that embed it include the Deliantra |
… | |
… | |
1680 | .Vb 1 |
2310 | .Vb 1 |
1681 | \& ev_win32.c required on win32 platforms only |
2311 | \& ev_win32.c required on win32 platforms only |
1682 | .Ve |
2312 | .Ve |
1683 | .PP |
2313 | .PP |
1684 | .Vb 5 |
2314 | .Vb 5 |
1685 | \& ev_select.c only when select backend is enabled (which is by default) |
2315 | \& ev_select.c only when select backend is enabled (which is enabled by default) |
1686 | \& ev_poll.c only when poll backend is enabled (disabled by default) |
2316 | \& ev_poll.c only when poll backend is enabled (disabled by default) |
1687 | \& ev_epoll.c only when the epoll backend is enabled (disabled by default) |
2317 | \& ev_epoll.c only when the epoll backend is enabled (disabled by default) |
1688 | \& ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
2318 | \& ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
1689 | \& ev_port.c only when the solaris port backend is enabled (disabled by default) |
2319 | \& ev_port.c only when the solaris port backend is enabled (disabled by default) |
1690 | .Ve |
2320 | .Ve |
… | |
… | |
1811 | otherwise another method will be used as fallback. This is the preferred |
2441 | otherwise another method will be used as fallback. This is the preferred |
1812 | backend for Solaris 10 systems. |
2442 | backend for Solaris 10 systems. |
1813 | .IP "\s-1EV_USE_DEVPOLL\s0" 4 |
2443 | .IP "\s-1EV_USE_DEVPOLL\s0" 4 |
1814 | .IX Item "EV_USE_DEVPOLL" |
2444 | .IX Item "EV_USE_DEVPOLL" |
1815 | reserved for future expansion, works like the \s-1USE\s0 symbols above. |
2445 | reserved for future expansion, works like the \s-1USE\s0 symbols above. |
|
|
2446 | .IP "\s-1EV_USE_INOTIFY\s0" 4 |
|
|
2447 | .IX Item "EV_USE_INOTIFY" |
|
|
2448 | If defined to be \f(CW1\fR, libev will compile in support for the Linux inotify |
|
|
2449 | interface to speed up \f(CW\*(C`ev_stat\*(C'\fR watchers. Its actual availability will |
|
|
2450 | be detected at runtime. |
1816 | .IP "\s-1EV_H\s0" 4 |
2451 | .IP "\s-1EV_H\s0" 4 |
1817 | .IX Item "EV_H" |
2452 | .IX Item "EV_H" |
1818 | The name of the \fIev.h\fR header file used to include it. The default if |
2453 | The name of the \fIev.h\fR header file used to include it. The default if |
1819 | undefined is \f(CW\*(C`<ev.h>\*(C'\fR in \fIevent.h\fR and \f(CW"ev.h"\fR in \fIev.c\fR. This |
2454 | undefined is \f(CW\*(C`<ev.h>\*(C'\fR in \fIevent.h\fR and \f(CW"ev.h"\fR in \fIev.c\fR. This |
1820 | can be used to virtually rename the \fIev.h\fR header file in case of conflicts. |
2455 | can be used to virtually rename the \fIev.h\fR header file in case of conflicts. |
… | |
… | |
1838 | If undefined or defined to \f(CW1\fR, then all event-loop-specific functions |
2473 | If undefined or defined to \f(CW1\fR, then all event-loop-specific functions |
1839 | will have the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument, and you can create |
2474 | will have the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument, and you can create |
1840 | additional independent event loops. Otherwise there will be no support |
2475 | additional independent event loops. Otherwise there will be no support |
1841 | for multiple event loops and there is no first event loop pointer |
2476 | for multiple event loops and there is no first event loop pointer |
1842 | argument. Instead, all functions act on the single default loop. |
2477 | argument. Instead, all functions act on the single default loop. |
|
|
2478 | .IP "\s-1EV_MINPRI\s0" 4 |
|
|
2479 | .IX Item "EV_MINPRI" |
|
|
2480 | .PD 0 |
|
|
2481 | .IP "\s-1EV_MAXPRI\s0" 4 |
|
|
2482 | .IX Item "EV_MAXPRI" |
|
|
2483 | .PD |
|
|
2484 | The range of allowed priorities. \f(CW\*(C`EV_MINPRI\*(C'\fR must be smaller or equal to |
|
|
2485 | \&\f(CW\*(C`EV_MAXPRI\*(C'\fR, but otherwise there are no non-obvious limitations. You can |
|
|
2486 | provide for more priorities by overriding those symbols (usually defined |
|
|
2487 | to be \f(CW\*(C`\-2\*(C'\fR and \f(CW2\fR, respectively). |
|
|
2488 | .Sp |
|
|
2489 | When doing priority-based operations, libev usually has to linearly search |
|
|
2490 | all the priorities, so having many of them (hundreds) uses a lot of space |
|
|
2491 | and time, so using the defaults of five priorities (\-2 .. +2) is usually |
|
|
2492 | fine. |
|
|
2493 | .Sp |
|
|
2494 | If your embedding app does not need any priorities, defining these both to |
|
|
2495 | \&\f(CW0\fR will save some memory and cpu. |
1843 | .IP "\s-1EV_PERIODICS\s0" 4 |
2496 | .IP "\s-1EV_PERIODIC_ENABLE\s0" 4 |
1844 | .IX Item "EV_PERIODICS" |
2497 | .IX Item "EV_PERIODIC_ENABLE" |
1845 | If undefined or defined to be \f(CW1\fR, then periodic timers are supported, |
2498 | If undefined or defined to be \f(CW1\fR, then periodic timers are supported. If |
1846 | otherwise not. This saves a few kb of code. |
2499 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
|
|
2500 | code. |
|
|
2501 | .IP "\s-1EV_IDLE_ENABLE\s0" 4 |
|
|
2502 | .IX Item "EV_IDLE_ENABLE" |
|
|
2503 | If undefined or defined to be \f(CW1\fR, then idle watchers are supported. If |
|
|
2504 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
|
|
2505 | code. |
|
|
2506 | .IP "\s-1EV_EMBED_ENABLE\s0" 4 |
|
|
2507 | .IX Item "EV_EMBED_ENABLE" |
|
|
2508 | If undefined or defined to be \f(CW1\fR, then embed watchers are supported. If |
|
|
2509 | defined to be \f(CW0\fR, then they are not. |
|
|
2510 | .IP "\s-1EV_STAT_ENABLE\s0" 4 |
|
|
2511 | .IX Item "EV_STAT_ENABLE" |
|
|
2512 | If undefined or defined to be \f(CW1\fR, then stat watchers are supported. If |
|
|
2513 | defined to be \f(CW0\fR, then they are not. |
|
|
2514 | .IP "\s-1EV_FORK_ENABLE\s0" 4 |
|
|
2515 | .IX Item "EV_FORK_ENABLE" |
|
|
2516 | If undefined or defined to be \f(CW1\fR, then fork watchers are supported. If |
|
|
2517 | defined to be \f(CW0\fR, then they are not. |
|
|
2518 | .IP "\s-1EV_MINIMAL\s0" 4 |
|
|
2519 | .IX Item "EV_MINIMAL" |
|
|
2520 | If you need to shave off some kilobytes of code at the expense of some |
|
|
2521 | speed, define this symbol to \f(CW1\fR. Currently only used for gcc to override |
|
|
2522 | some inlining decisions, saves roughly 30% codesize of amd64. |
|
|
2523 | .IP "\s-1EV_PID_HASHSIZE\s0" 4 |
|
|
2524 | .IX Item "EV_PID_HASHSIZE" |
|
|
2525 | \&\f(CW\*(C`ev_child\*(C'\fR watchers use a small hash table to distribute workload by |
|
|
2526 | pid. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), usually more |
|
|
2527 | than enough. If you need to manage thousands of children you might want to |
|
|
2528 | increase this value (\fImust\fR be a power of two). |
|
|
2529 | .IP "\s-1EV_INOTIFY_HASHSIZE\s0" 4 |
|
|
2530 | .IX Item "EV_INOTIFY_HASHSIZE" |
|
|
2531 | \&\f(CW\*(C`ev_staz\*(C'\fR watchers use a small hash table to distribute workload by |
|
|
2532 | inotify watch id. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), |
|
|
2533 | usually more than enough. If you need to manage thousands of \f(CW\*(C`ev_stat\*(C'\fR |
|
|
2534 | watchers you might want to increase this value (\fImust\fR be a power of |
|
|
2535 | two). |
1847 | .IP "\s-1EV_COMMON\s0" 4 |
2536 | .IP "\s-1EV_COMMON\s0" 4 |
1848 | .IX Item "EV_COMMON" |
2537 | .IX Item "EV_COMMON" |
1849 | By default, all watchers have a \f(CW\*(C`void *data\*(C'\fR member. By redefining |
2538 | By default, all watchers have a \f(CW\*(C`void *data\*(C'\fR member. By redefining |
1850 | this macro to a something else you can include more and other types of |
2539 | this macro to a something else you can include more and other types of |
1851 | members. You have to define it each time you include one of the files, |
2540 | members. You have to define it each time you include one of the files, |
… | |
… | |
1881 | interface) and \fI\s-1EV\s0.xs\fR (implementation) files. Only the \fI\s-1EV\s0.xs\fR file |
2570 | interface) and \fI\s-1EV\s0.xs\fR (implementation) files. Only the \fI\s-1EV\s0.xs\fR file |
1882 | will be compiled. It is pretty complex because it provides its own header |
2571 | will be compiled. It is pretty complex because it provides its own header |
1883 | file. |
2572 | file. |
1884 | .Sp |
2573 | .Sp |
1885 | The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file |
2574 | The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file |
1886 | that everybody includes and which overrides some autoconf choices: |
2575 | that everybody includes and which overrides some configure choices: |
1887 | .Sp |
2576 | .Sp |
1888 | .Vb 4 |
2577 | .Vb 9 |
|
|
2578 | \& #define EV_MINIMAL 1 |
1889 | \& #define EV_USE_POLL 0 |
2579 | \& #define EV_USE_POLL 0 |
1890 | \& #define EV_MULTIPLICITY 0 |
2580 | \& #define EV_MULTIPLICITY 0 |
1891 | \& #define EV_PERIODICS 0 |
2581 | \& #define EV_PERIODIC_ENABLE 0 |
|
|
2582 | \& #define EV_STAT_ENABLE 0 |
|
|
2583 | \& #define EV_FORK_ENABLE 0 |
1892 | \& #define EV_CONFIG_H <config.h> |
2584 | \& #define EV_CONFIG_H <config.h> |
|
|
2585 | \& #define EV_MINPRI 0 |
|
|
2586 | \& #define EV_MAXPRI 0 |
1893 | .Ve |
2587 | .Ve |
1894 | .Sp |
2588 | .Sp |
1895 | .Vb 1 |
2589 | .Vb 1 |
1896 | \& #include "ev++.h" |
2590 | \& #include "ev++.h" |
1897 | .Ve |
2591 | .Ve |
… | |
… | |
1900 | .Sp |
2594 | .Sp |
1901 | .Vb 2 |
2595 | .Vb 2 |
1902 | \& #include "ev_cpp.h" |
2596 | \& #include "ev_cpp.h" |
1903 | \& #include "ev.c" |
2597 | \& #include "ev.c" |
1904 | .Ve |
2598 | .Ve |
|
|
2599 | .SH "COMPLEXITIES" |
|
|
2600 | .IX Header "COMPLEXITIES" |
|
|
2601 | In this section the complexities of (many of) the algorithms used inside |
|
|
2602 | libev will be explained. For complexity discussions about backends see the |
|
|
2603 | documentation for \f(CW\*(C`ev_default_init\*(C'\fR. |
|
|
2604 | .Sp |
|
|
2605 | All of the following are about amortised time: If an array needs to be |
|
|
2606 | extended, libev needs to realloc and move the whole array, but this |
|
|
2607 | happens asymptotically never with higher number of elements, so O(1) might |
|
|
2608 | mean it might do a lengthy realloc operation in rare cases, but on average |
|
|
2609 | it is much faster and asymptotically approaches constant time. |
|
|
2610 | .RS 4 |
|
|
2611 | .IP "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" 4 |
|
|
2612 | .IX Item "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" |
|
|
2613 | This means that, when you have a watcher that triggers in one hour and |
|
|
2614 | there are 100 watchers that would trigger before that then inserting will |
|
|
2615 | have to skip those 100 watchers. |
|
|
2616 | .IP "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" 4 |
|
|
2617 | .IX Item "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" |
|
|
2618 | That means that for changing a timer costs less than removing/adding them |
|
|
2619 | as only the relative motion in the event queue has to be paid for. |
|
|
2620 | .IP "Starting io/check/prepare/idle/signal/child watchers: O(1)" 4 |
|
|
2621 | .IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)" |
|
|
2622 | These just add the watcher into an array or at the head of a list. |
|
|
2623 | =item Stopping check/prepare/idle watchers: O(1) |
|
|
2624 | .IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % \s-1EV_PID_HASHSIZE\s0))" 4 |
|
|
2625 | .IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))" |
|
|
2626 | These watchers are stored in lists then need to be walked to find the |
|
|
2627 | correct watcher to remove. The lists are usually short (you don't usually |
|
|
2628 | have many watchers waiting for the same fd or signal). |
|
|
2629 | .IP "Finding the next timer per loop iteration: O(1)" 4 |
|
|
2630 | .IX Item "Finding the next timer per loop iteration: O(1)" |
|
|
2631 | .PD 0 |
|
|
2632 | .IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4 |
|
|
2633 | .IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" |
|
|
2634 | .PD |
|
|
2635 | A change means an I/O watcher gets started or stopped, which requires |
|
|
2636 | libev to recalculate its status (and possibly tell the kernel). |
|
|
2637 | .IP "Activating one watcher: O(1)" 4 |
|
|
2638 | .IX Item "Activating one watcher: O(1)" |
|
|
2639 | .PD 0 |
|
|
2640 | .IP "Priority handling: O(number_of_priorities)" 4 |
|
|
2641 | .IX Item "Priority handling: O(number_of_priorities)" |
|
|
2642 | .PD |
|
|
2643 | Priorities are implemented by allocating some space for each |
|
|
2644 | priority. When doing priority-based operations, libev usually has to |
|
|
2645 | linearly search all the priorities. |
|
|
2646 | .RE |
|
|
2647 | .RS 4 |
1905 | .SH "AUTHOR" |
2648 | .SH "AUTHOR" |
1906 | .IX Header "AUTHOR" |
2649 | .IX Header "AUTHOR" |
1907 | Marc Lehmann <libev@schmorp.de>. |
2650 | Marc Lehmann <libev@schmorp.de>. |