… | |
… | |
127 | .\} |
127 | .\} |
128 | .rm #[ #] #H #V #F C |
128 | .rm #[ #] #H #V #F C |
129 | .\" ======================================================================== |
129 | .\" ======================================================================== |
130 | .\" |
130 | .\" |
131 | .IX Title ""<STANDARD INPUT>" 1" |
131 | .IX Title ""<STANDARD INPUT>" 1" |
132 | .TH "<STANDARD INPUT>" 1 "2007-11-24" "perl v5.8.8" "User Contributed Perl Documentation" |
132 | .TH "<STANDARD INPUT>" 1 "2007-12-07" "perl v5.8.8" "User Contributed Perl Documentation" |
133 | .SH "NAME" |
133 | .SH "NAME" |
134 | libev \- a high performance full\-featured event loop written in C |
134 | libev \- a high performance full\-featured event loop written in C |
135 | .SH "SYNOPSIS" |
135 | .SH "SYNOPSIS" |
136 | .IX Header "SYNOPSIS" |
136 | .IX Header "SYNOPSIS" |
137 | .Vb 1 |
137 | .Vb 1 |
138 | \& #include <ev.h> |
138 | \& #include <ev.h> |
139 | .Ve |
139 | .Ve |
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140 | .SH "EXAMPLE PROGRAM" |
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141 | .IX Header "EXAMPLE PROGRAM" |
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142 | .Vb 1 |
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143 | \& #include <ev.h> |
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144 | .Ve |
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145 | .PP |
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146 | .Vb 2 |
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147 | \& ev_io stdin_watcher; |
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148 | \& ev_timer timeout_watcher; |
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149 | .Ve |
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150 | .PP |
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151 | .Vb 8 |
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152 | \& /* called when data readable on stdin */ |
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153 | \& static void |
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154 | \& stdin_cb (EV_P_ struct ev_io *w, int revents) |
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155 | \& { |
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156 | \& /* puts ("stdin ready"); */ |
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157 | \& ev_io_stop (EV_A_ w); /* just a syntax example */ |
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158 | \& ev_unloop (EV_A_ EVUNLOOP_ALL); /* leave all loop calls */ |
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159 | \& } |
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160 | .Ve |
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161 | .PP |
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162 | .Vb 6 |
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163 | \& static void |
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164 | \& timeout_cb (EV_P_ struct ev_timer *w, int revents) |
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165 | \& { |
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166 | \& /* puts ("timeout"); */ |
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167 | \& ev_unloop (EV_A_ EVUNLOOP_ONE); /* leave one loop call */ |
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168 | \& } |
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169 | .Ve |
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170 | .PP |
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171 | .Vb 4 |
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172 | \& int |
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173 | \& main (void) |
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174 | \& { |
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175 | \& struct ev_loop *loop = ev_default_loop (0); |
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176 | .Ve |
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177 | .PP |
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178 | .Vb 3 |
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179 | \& /* initialise an io watcher, then start it */ |
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180 | \& ev_io_init (&stdin_watcher, stdin_cb, /*STDIN_FILENO*/ 0, EV_READ); |
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181 | \& ev_io_start (loop, &stdin_watcher); |
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182 | .Ve |
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183 | .PP |
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184 | .Vb 3 |
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185 | \& /* simple non-repeating 5.5 second timeout */ |
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186 | \& ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.); |
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187 | \& ev_timer_start (loop, &timeout_watcher); |
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188 | .Ve |
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189 | .PP |
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190 | .Vb 2 |
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191 | \& /* loop till timeout or data ready */ |
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192 | \& ev_loop (loop, 0); |
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193 | .Ve |
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194 | .PP |
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195 | .Vb 2 |
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196 | \& return 0; |
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197 | \& } |
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198 | .Ve |
140 | .SH "DESCRIPTION" |
199 | .SH "DESCRIPTION" |
141 | .IX Header "DESCRIPTION" |
200 | .IX Header "DESCRIPTION" |
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201 | The newest version of this document is also available as a html-formatted |
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202 | web page you might find easier to navigate when reading it for the first |
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203 | time: <http://cvs.schmorp.de/libev/ev.html>. |
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204 | .PP |
142 | Libev is an event loop: you register interest in certain events (such as a |
205 | Libev is an event loop: you register interest in certain events (such as a |
143 | file descriptor being readable or a timeout occuring), and it will manage |
206 | file descriptor being readable or a timeout occuring), and it will manage |
144 | these event sources and provide your program with events. |
207 | these event sources and provide your program with events. |
145 | .PP |
208 | .PP |
146 | To do this, it must take more or less complete control over your process |
209 | To do this, it must take more or less complete control over your process |
… | |
… | |
151 | watchers\fR, which are relatively small C structures you initialise with the |
214 | watchers\fR, which are relatively small C structures you initialise with the |
152 | details of the event, and then hand it over to libev by \fIstarting\fR the |
215 | details of the event, and then hand it over to libev by \fIstarting\fR the |
153 | watcher. |
216 | watcher. |
154 | .SH "FEATURES" |
217 | .SH "FEATURES" |
155 | .IX Header "FEATURES" |
218 | .IX Header "FEATURES" |
156 | Libev supports select, poll, the linux-specific epoll and the bsd-specific |
219 | Libev supports \f(CW\*(C`select\*(C'\fR, \f(CW\*(C`poll\*(C'\fR, the Linux-specific \f(CW\*(C`epoll\*(C'\fR, the |
157 | kqueue mechanisms for file descriptor events, relative timers, absolute |
220 | BSD-specific \f(CW\*(C`kqueue\*(C'\fR and the Solaris-specific event port mechanisms |
158 | timers with customised rescheduling, signal events, process status change |
221 | for file descriptor events (\f(CW\*(C`ev_io\*(C'\fR), the Linux \f(CW\*(C`inotify\*(C'\fR interface |
159 | events (related to \s-1SIGCHLD\s0), and event watchers dealing with the event |
222 | (for \f(CW\*(C`ev_stat\*(C'\fR), relative timers (\f(CW\*(C`ev_timer\*(C'\fR), absolute timers |
160 | loop mechanism itself (idle, prepare and check watchers). It also is quite |
223 | with customised rescheduling (\f(CW\*(C`ev_periodic\*(C'\fR), synchronous signals |
161 | fast (see this benchmark comparing |
224 | (\f(CW\*(C`ev_signal\*(C'\fR), process status change events (\f(CW\*(C`ev_child\*(C'\fR), and event |
162 | it to libevent for example). |
225 | watchers dealing with the event loop mechanism itself (\f(CW\*(C`ev_idle\*(C'\fR, |
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226 | \&\f(CW\*(C`ev_embed\*(C'\fR, \f(CW\*(C`ev_prepare\*(C'\fR and \f(CW\*(C`ev_check\*(C'\fR watchers) as well as |
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227 | file watchers (\f(CW\*(C`ev_stat\*(C'\fR) and even limited support for fork events |
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228 | (\f(CW\*(C`ev_fork\*(C'\fR). |
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229 | .PP |
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230 | It also is quite fast (see this |
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231 | benchmark comparing it to libevent |
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232 | for example). |
163 | .SH "CONVENTIONS" |
233 | .SH "CONVENTIONS" |
164 | .IX Header "CONVENTIONS" |
234 | .IX Header "CONVENTIONS" |
165 | Libev is very configurable. In this manual the default configuration |
235 | Libev is very configurable. In this manual the default configuration will |
166 | will be described, which supports multiple event loops. For more info |
236 | be described, which supports multiple event loops. For more info about |
167 | about various configuration options please have a look at the file |
237 | various configuration options please have a look at \fB\s-1EMBED\s0\fR section in |
168 | \&\fI\s-1README\s0.embed\fR in the libev distribution. If libev was configured without |
238 | this manual. If libev was configured without support for multiple event |
169 | support for multiple event loops, then all functions taking an initial |
239 | loops, then all functions taking an initial argument of name \f(CW\*(C`loop\*(C'\fR |
170 | argument of name \f(CW\*(C`loop\*(C'\fR (which is always of type \f(CW\*(C`struct ev_loop *\*(C'\fR) |
240 | (which is always of type \f(CW\*(C`struct ev_loop *\*(C'\fR) will not have this argument. |
171 | will not have this argument. |
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172 | .SH "TIME REPRESENTATION" |
241 | .SH "TIME REPRESENTATION" |
173 | .IX Header "TIME REPRESENTATION" |
242 | .IX Header "TIME REPRESENTATION" |
174 | Libev represents time as a single floating point number, representing the |
243 | Libev represents time as a single floating point number, representing the |
175 | (fractional) number of seconds since the (\s-1POSIX\s0) epoch (somewhere near |
244 | (fractional) number of seconds since the (\s-1POSIX\s0) epoch (somewhere near |
176 | the beginning of 1970, details are complicated, don't ask). This type is |
245 | the beginning of 1970, details are complicated, don't ask). This type is |
… | |
… | |
201 | Usually, it's a good idea to terminate if the major versions mismatch, |
270 | Usually, it's a good idea to terminate if the major versions mismatch, |
202 | as this indicates an incompatible change. Minor versions are usually |
271 | as this indicates an incompatible change. Minor versions are usually |
203 | compatible to older versions, so a larger minor version alone is usually |
272 | compatible to older versions, so a larger minor version alone is usually |
204 | not a problem. |
273 | not a problem. |
205 | .Sp |
274 | .Sp |
206 | Example: make sure we haven't accidentally been linked against the wrong |
275 | Example: Make sure we haven't accidentally been linked against the wrong |
207 | version: |
276 | version. |
208 | .Sp |
277 | .Sp |
209 | .Vb 3 |
278 | .Vb 3 |
210 | \& assert (("libev version mismatch", |
279 | \& assert (("libev version mismatch", |
211 | \& ev_version_major () == EV_VERSION_MAJOR |
280 | \& ev_version_major () == EV_VERSION_MAJOR |
212 | \& && ev_version_minor () >= EV_VERSION_MINOR)); |
281 | \& && ev_version_minor () >= EV_VERSION_MINOR)); |
… | |
… | |
242 | recommended ones. |
311 | recommended ones. |
243 | .Sp |
312 | .Sp |
244 | See the description of \f(CW\*(C`ev_embed\*(C'\fR watchers for more info. |
313 | See the description of \f(CW\*(C`ev_embed\*(C'\fR watchers for more info. |
245 | .IP "ev_set_allocator (void *(*cb)(void *ptr, long size))" 4 |
314 | .IP "ev_set_allocator (void *(*cb)(void *ptr, long size))" 4 |
246 | .IX Item "ev_set_allocator (void *(*cb)(void *ptr, long size))" |
315 | .IX Item "ev_set_allocator (void *(*cb)(void *ptr, long size))" |
247 | Sets the allocation function to use (the prototype is similar to the |
316 | Sets the allocation function to use (the prototype is similar \- the |
248 | realloc C function, the semantics are identical). It is used to allocate |
317 | semantics is identical \- to the realloc C function). It is used to |
249 | and free memory (no surprises here). If it returns zero when memory |
318 | allocate and free memory (no surprises here). If it returns zero when |
250 | needs to be allocated, the library might abort or take some potentially |
319 | memory needs to be allocated, the library might abort or take some |
251 | destructive action. The default is your system realloc function. |
320 | potentially destructive action. The default is your system realloc |
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321 | function. |
252 | .Sp |
322 | .Sp |
253 | You could override this function in high-availability programs to, say, |
323 | You could override this function in high-availability programs to, say, |
254 | free some memory if it cannot allocate memory, to use a special allocator, |
324 | free some memory if it cannot allocate memory, to use a special allocator, |
255 | or even to sleep a while and retry until some memory is available. |
325 | or even to sleep a while and retry until some memory is available. |
256 | .Sp |
326 | .Sp |
257 | Example: replace the libev allocator with one that waits a bit and then |
327 | Example: Replace the libev allocator with one that waits a bit and then |
258 | retries: better than mine). |
328 | retries). |
259 | .Sp |
329 | .Sp |
260 | .Vb 6 |
330 | .Vb 6 |
261 | \& static void * |
331 | \& static void * |
262 | \& persistent_realloc (void *ptr, long size) |
332 | \& persistent_realloc (void *ptr, size_t size) |
263 | \& { |
333 | \& { |
264 | \& for (;;) |
334 | \& for (;;) |
265 | \& { |
335 | \& { |
266 | \& void *newptr = realloc (ptr, size); |
336 | \& void *newptr = realloc (ptr, size); |
267 | .Ve |
337 | .Ve |
… | |
… | |
289 | callback is set, then libev will expect it to remedy the sitution, no |
359 | callback is set, then libev will expect it to remedy the sitution, no |
290 | matter what, when it returns. That is, libev will generally retry the |
360 | matter what, when it returns. That is, libev will generally retry the |
291 | requested operation, or, if the condition doesn't go away, do bad stuff |
361 | requested operation, or, if the condition doesn't go away, do bad stuff |
292 | (such as abort). |
362 | (such as abort). |
293 | .Sp |
363 | .Sp |
294 | Example: do the same thing as libev does internally: |
364 | Example: This is basically the same thing that libev does internally, too. |
295 | .Sp |
365 | .Sp |
296 | .Vb 6 |
366 | .Vb 6 |
297 | \& static void |
367 | \& static void |
298 | \& fatal_error (const char *msg) |
368 | \& fatal_error (const char *msg) |
299 | \& { |
369 | \& { |
… | |
… | |
345 | or setgid) then libev will \fInot\fR look at the environment variable |
415 | or setgid) then libev will \fInot\fR look at the environment variable |
346 | \&\f(CW\*(C`LIBEV_FLAGS\*(C'\fR. Otherwise (the default), this environment variable will |
416 | \&\f(CW\*(C`LIBEV_FLAGS\*(C'\fR. Otherwise (the default), this environment variable will |
347 | override the flags completely if it is found in the environment. This is |
417 | override the flags completely if it is found in the environment. This is |
348 | useful to try out specific backends to test their performance, or to work |
418 | useful to try out specific backends to test their performance, or to work |
349 | around bugs. |
419 | around bugs. |
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420 | .ie n .IP """EVFLAG_FORKCHECK""" 4 |
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421 | .el .IP "\f(CWEVFLAG_FORKCHECK\fR" 4 |
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422 | .IX Item "EVFLAG_FORKCHECK" |
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423 | Instead of calling \f(CW\*(C`ev_default_fork\*(C'\fR or \f(CW\*(C`ev_loop_fork\*(C'\fR manually after |
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424 | a fork, you can also make libev check for a fork in each iteration by |
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425 | enabling this flag. |
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426 | .Sp |
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427 | This works by calling \f(CW\*(C`getpid ()\*(C'\fR on every iteration of the loop, |
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428 | and thus this might slow down your event loop if you do a lot of loop |
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429 | iterations and little real work, but is usually not noticeable (on my |
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430 | Linux system for example, \f(CW\*(C`getpid\*(C'\fR is actually a simple 5\-insn sequence |
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431 | without a syscall and thus \fIvery\fR fast, but my Linux system also has |
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432 | \&\f(CW\*(C`pthread_atfork\*(C'\fR which is even faster). |
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433 | .Sp |
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434 | The big advantage of this flag is that you can forget about fork (and |
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435 | forget about forgetting to tell libev about forking) when you use this |
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436 | flag. |
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437 | .Sp |
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438 | This flag setting cannot be overriden or specified in the \f(CW\*(C`LIBEV_FLAGS\*(C'\fR |
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439 | environment variable. |
350 | .ie n .IP """EVBACKEND_SELECT"" (value 1, portable select backend)" 4 |
440 | .ie n .IP """EVBACKEND_SELECT"" (value 1, portable select backend)" 4 |
351 | .el .IP "\f(CWEVBACKEND_SELECT\fR (value 1, portable select backend)" 4 |
441 | .el .IP "\f(CWEVBACKEND_SELECT\fR (value 1, portable select backend)" 4 |
352 | .IX Item "EVBACKEND_SELECT (value 1, portable select backend)" |
442 | .IX Item "EVBACKEND_SELECT (value 1, portable select backend)" |
353 | This is your standard \fIselect\fR\|(2) backend. Not \fIcompletely\fR standard, as |
443 | This is your standard \fIselect\fR\|(2) backend. Not \fIcompletely\fR standard, as |
354 | libev tries to roll its own fd_set with no limits on the number of fds, |
444 | libev tries to roll its own fd_set with no limits on the number of fds, |
… | |
… | |
448 | Similar to \f(CW\*(C`ev_default_loop\*(C'\fR, but always creates a new event loop that is |
538 | Similar to \f(CW\*(C`ev_default_loop\*(C'\fR, but always creates a new event loop that is |
449 | always distinct from the default loop. Unlike the default loop, it cannot |
539 | always distinct from the default loop. Unlike the default loop, it cannot |
450 | handle signal and child watchers, and attempts to do so will be greeted by |
540 | handle signal and child watchers, and attempts to do so will be greeted by |
451 | undefined behaviour (or a failed assertion if assertions are enabled). |
541 | undefined behaviour (or a failed assertion if assertions are enabled). |
452 | .Sp |
542 | .Sp |
453 | Example: try to create a event loop that uses epoll and nothing else. |
543 | Example: Try to create a event loop that uses epoll and nothing else. |
454 | .Sp |
544 | .Sp |
455 | .Vb 3 |
545 | .Vb 3 |
456 | \& struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
546 | \& struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
457 | \& if (!epoller) |
547 | \& if (!epoller) |
458 | \& fatal ("no epoll found here, maybe it hides under your chair"); |
548 | \& fatal ("no epoll found here, maybe it hides under your chair"); |
… | |
… | |
495 | .IP "ev_loop_fork (loop)" 4 |
585 | .IP "ev_loop_fork (loop)" 4 |
496 | .IX Item "ev_loop_fork (loop)" |
586 | .IX Item "ev_loop_fork (loop)" |
497 | Like \f(CW\*(C`ev_default_fork\*(C'\fR, but acts on an event loop created by |
587 | Like \f(CW\*(C`ev_default_fork\*(C'\fR, but acts on an event loop created by |
498 | \&\f(CW\*(C`ev_loop_new\*(C'\fR. Yes, you have to call this on every allocated event loop |
588 | \&\f(CW\*(C`ev_loop_new\*(C'\fR. Yes, you have to call this on every allocated event loop |
499 | after fork, and how you do this is entirely your own problem. |
589 | after fork, and how you do this is entirely your own problem. |
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590 | .IP "unsigned int ev_loop_count (loop)" 4 |
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591 | .IX Item "unsigned int ev_loop_count (loop)" |
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592 | Returns the count of loop iterations for the loop, which is identical to |
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593 | the number of times libev did poll for new events. It starts at \f(CW0\fR and |
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594 | happily wraps around with enough iterations. |
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595 | .Sp |
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596 | This value can sometimes be useful as a generation counter of sorts (it |
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597 | \&\*(L"ticks\*(R" the number of loop iterations), as it roughly corresponds with |
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598 | \&\f(CW\*(C`ev_prepare\*(C'\fR and \f(CW\*(C`ev_check\*(C'\fR calls. |
500 | .IP "unsigned int ev_backend (loop)" 4 |
599 | .IP "unsigned int ev_backend (loop)" 4 |
501 | .IX Item "unsigned int ev_backend (loop)" |
600 | .IX Item "unsigned int ev_backend (loop)" |
502 | Returns one of the \f(CW\*(C`EVBACKEND_*\*(C'\fR flags indicating the event backend in |
601 | Returns one of the \f(CW\*(C`EVBACKEND_*\*(C'\fR flags indicating the event backend in |
503 | use. |
602 | use. |
504 | .IP "ev_tstamp ev_now (loop)" 4 |
603 | .IP "ev_tstamp ev_now (loop)" 4 |
… | |
… | |
556 | \& be handled here by queueing them when their watcher gets executed. |
655 | \& be handled here by queueing them when their watcher gets executed. |
557 | \& - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
656 | \& - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
558 | \& were used, return, otherwise continue with step *. |
657 | \& were used, return, otherwise continue with step *. |
559 | .Ve |
658 | .Ve |
560 | .Sp |
659 | .Sp |
561 | Example: queue some jobs and then loop until no events are outsanding |
660 | Example: Queue some jobs and then loop until no events are outsanding |
562 | anymore. |
661 | anymore. |
563 | .Sp |
662 | .Sp |
564 | .Vb 4 |
663 | .Vb 4 |
565 | \& ... queue jobs here, make sure they register event watchers as long |
664 | \& ... queue jobs here, make sure they register event watchers as long |
566 | \& ... as they still have work to do (even an idle watcher will do..) |
665 | \& ... as they still have work to do (even an idle watcher will do..) |
… | |
… | |
588 | visible to the libev user and should not keep \f(CW\*(C`ev_loop\*(C'\fR from exiting if |
687 | visible to the libev user and should not keep \f(CW\*(C`ev_loop\*(C'\fR from exiting if |
589 | no event watchers registered by it are active. It is also an excellent |
688 | no event watchers registered by it are active. It is also an excellent |
590 | way to do this for generic recurring timers or from within third-party |
689 | way to do this for generic recurring timers or from within third-party |
591 | libraries. Just remember to \fIunref after start\fR and \fIref before stop\fR. |
690 | libraries. Just remember to \fIunref after start\fR and \fIref before stop\fR. |
592 | .Sp |
691 | .Sp |
593 | Example: create a signal watcher, but keep it from keeping \f(CW\*(C`ev_loop\*(C'\fR |
692 | Example: Create a signal watcher, but keep it from keeping \f(CW\*(C`ev_loop\*(C'\fR |
594 | running when nothing else is active. |
693 | running when nothing else is active. |
595 | .Sp |
694 | .Sp |
596 | .Vb 4 |
695 | .Vb 4 |
597 | \& struct dv_signal exitsig; |
696 | \& struct ev_signal exitsig; |
598 | \& ev_signal_init (&exitsig, sig_cb, SIGINT); |
697 | \& ev_signal_init (&exitsig, sig_cb, SIGINT); |
599 | \& ev_signal_start (myloop, &exitsig); |
698 | \& ev_signal_start (loop, &exitsig); |
600 | \& evf_unref (myloop); |
699 | \& evf_unref (loop); |
601 | .Ve |
700 | .Ve |
602 | .Sp |
701 | .Sp |
603 | Example: for some weird reason, unregister the above signal handler again. |
702 | Example: For some weird reason, unregister the above signal handler again. |
604 | .Sp |
703 | .Sp |
605 | .Vb 2 |
704 | .Vb 2 |
606 | \& ev_ref (myloop); |
705 | \& ev_ref (loop); |
607 | \& ev_signal_stop (myloop, &exitsig); |
706 | \& ev_signal_stop (loop, &exitsig); |
608 | .Ve |
707 | .Ve |
609 | .SH "ANATOMY OF A WATCHER" |
708 | .SH "ANATOMY OF A WATCHER" |
610 | .IX Header "ANATOMY OF A WATCHER" |
709 | .IX Header "ANATOMY OF A WATCHER" |
611 | A watcher is a structure that you create and register to record your |
710 | A watcher is a structure that you create and register to record your |
612 | interest in some event. For instance, if you want to wait for \s-1STDIN\s0 to |
711 | interest in some event. For instance, if you want to wait for \s-1STDIN\s0 to |
… | |
… | |
684 | The signal specified in the \f(CW\*(C`ev_signal\*(C'\fR watcher has been received by a thread. |
783 | 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 |
784 | .ie n .IP """EV_CHILD""" 4 |
686 | .el .IP "\f(CWEV_CHILD\fR" 4 |
785 | .el .IP "\f(CWEV_CHILD\fR" 4 |
687 | .IX Item "EV_CHILD" |
786 | .IX Item "EV_CHILD" |
688 | The pid specified in the \f(CW\*(C`ev_child\*(C'\fR watcher has received a status change. |
787 | The pid specified in the \f(CW\*(C`ev_child\*(C'\fR watcher has received a status change. |
|
|
788 | .ie n .IP """EV_STAT""" 4 |
|
|
789 | .el .IP "\f(CWEV_STAT\fR" 4 |
|
|
790 | .IX Item "EV_STAT" |
|
|
791 | The path specified in the \f(CW\*(C`ev_stat\*(C'\fR watcher changed its attributes somehow. |
689 | .ie n .IP """EV_IDLE""" 4 |
792 | .ie n .IP """EV_IDLE""" 4 |
690 | .el .IP "\f(CWEV_IDLE\fR" 4 |
793 | .el .IP "\f(CWEV_IDLE\fR" 4 |
691 | .IX Item "EV_IDLE" |
794 | .IX Item "EV_IDLE" |
692 | The \f(CW\*(C`ev_idle\*(C'\fR watcher has determined that you have nothing better to do. |
795 | 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 |
796 | .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 |
806 | \&\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 |
807 | 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 |
808 | 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 |
809 | (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). |
810 | \&\f(CW\*(C`ev_loop\*(C'\fR from blocking). |
|
|
811 | .ie n .IP """EV_EMBED""" 4 |
|
|
812 | .el .IP "\f(CWEV_EMBED\fR" 4 |
|
|
813 | .IX Item "EV_EMBED" |
|
|
814 | The embedded event loop specified in the \f(CW\*(C`ev_embed\*(C'\fR watcher needs attention. |
|
|
815 | .ie n .IP """EV_FORK""" 4 |
|
|
816 | .el .IP "\f(CWEV_FORK\fR" 4 |
|
|
817 | .IX Item "EV_FORK" |
|
|
818 | The event loop has been resumed in the child process after fork (see |
|
|
819 | \&\f(CW\*(C`ev_fork\*(C'\fR). |
708 | .ie n .IP """EV_ERROR""" 4 |
820 | .ie n .IP """EV_ERROR""" 4 |
709 | .el .IP "\f(CWEV_ERROR\fR" 4 |
821 | .el .IP "\f(CWEV_ERROR\fR" 4 |
710 | .IX Item "EV_ERROR" |
822 | .IX Item "EV_ERROR" |
711 | An unspecified error has occured, the watcher has been stopped. This might |
823 | An unspecified error has occured, the watcher has been stopped. This might |
712 | happen because the watcher could not be properly started because libev |
824 | happen because the watcher could not be properly started because libev |
… | |
… | |
717 | Libev will usually signal a few \*(L"dummy\*(R" events together with an error, |
829 | Libev will usually signal a few \*(L"dummy\*(R" events together with an error, |
718 | for example it might indicate that a fd is readable or writable, and if |
830 | for example it might indicate that a fd is readable or writable, and if |
719 | your callbacks is well-written it can just attempt the operation and cope |
831 | your callbacks is well-written it can just attempt the operation and cope |
720 | with the error from \fIread()\fR or \fIwrite()\fR. This will not work in multithreaded |
832 | with the error from \fIread()\fR or \fIwrite()\fR. This will not work in multithreaded |
721 | programs, though, so beware. |
833 | programs, though, so beware. |
722 | .Sh "\s-1SUMMARY\s0 \s-1OF\s0 \s-1GENERIC\s0 \s-1WATCHER\s0 \s-1FUNCTIONS\s0" |
834 | .Sh "\s-1GENERIC\s0 \s-1WATCHER\s0 \s-1FUNCTIONS\s0" |
723 | .IX Subsection "SUMMARY OF GENERIC WATCHER FUNCTIONS" |
835 | .IX Subsection "GENERIC WATCHER FUNCTIONS" |
724 | In the following description, \f(CW\*(C`TYPE\*(C'\fR stands for the watcher type, |
836 | In the following description, \f(CW\*(C`TYPE\*(C'\fR stands for the watcher type, |
725 | e.g. \f(CW\*(C`timer\*(C'\fR for \f(CW\*(C`ev_timer\*(C'\fR watchers and \f(CW\*(C`io\*(C'\fR for \f(CW\*(C`ev_io\*(C'\fR watchers. |
837 | e.g. \f(CW\*(C`timer\*(C'\fR for \f(CW\*(C`ev_timer\*(C'\fR watchers and \f(CW\*(C`io\*(C'\fR for \f(CW\*(C`ev_io\*(C'\fR watchers. |
726 | .ie n .IP """ev_init"" (ev_TYPE *watcher, callback)" 4 |
838 | .ie n .IP """ev_init"" (ev_TYPE *watcher, callback)" 4 |
727 | .el .IP "\f(CWev_init\fR (ev_TYPE *watcher, callback)" 4 |
839 | .el .IP "\f(CWev_init\fR (ev_TYPE *watcher, callback)" 4 |
728 | .IX Item "ev_init (ev_TYPE *watcher, callback)" |
840 | .IX Item "ev_init (ev_TYPE *watcher, callback)" |
… | |
… | |
734 | which rolls both calls into one. |
846 | which rolls both calls into one. |
735 | .Sp |
847 | .Sp |
736 | You can reinitialise a watcher at any time as long as it has been stopped |
848 | You can reinitialise a watcher at any time as long as it has been stopped |
737 | (or never started) and there are no pending events outstanding. |
849 | (or never started) and there are no pending events outstanding. |
738 | .Sp |
850 | .Sp |
739 | The callbakc is always of type \f(CW\*(C`void (*)(ev_loop *loop, ev_TYPE *watcher, |
851 | The callback is always of type \f(CW\*(C`void (*)(ev_loop *loop, ev_TYPE *watcher, |
740 | int revents)\*(C'\fR. |
852 | int revents)\*(C'\fR. |
741 | .ie n .IP """ev_TYPE_set"" (ev_TYPE *, [args])" 4 |
853 | .ie n .IP """ev_TYPE_set"" (ev_TYPE *, [args])" 4 |
742 | .el .IP "\f(CWev_TYPE_set\fR (ev_TYPE *, [args])" 4 |
854 | .el .IP "\f(CWev_TYPE_set\fR (ev_TYPE *, [args])" 4 |
743 | .IX Item "ev_TYPE_set (ev_TYPE *, [args])" |
855 | .IX Item "ev_TYPE_set (ev_TYPE *, [args])" |
744 | This macro initialises the type-specific parts of a watcher. You need to |
856 | This macro initialises the type-specific parts of a watcher. You need to |
… | |
… | |
779 | Returns a true value iff the watcher is pending, (i.e. it has outstanding |
891 | 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 |
892 | 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 |
893 | 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 |
894 | \&\f(CW\*(C`ev_TYPE_set\*(C'\fR is safe) and you must make sure the watcher is available to |
783 | libev (e.g. you cnanot \f(CW\*(C`free ()\*(C'\fR it). |
895 | libev (e.g. you cnanot \f(CW\*(C`free ()\*(C'\fR it). |
784 | .IP "callback = ev_cb (ev_TYPE *watcher)" 4 |
896 | .IP "callback ev_cb (ev_TYPE *watcher)" 4 |
785 | .IX Item "callback = ev_cb (ev_TYPE *watcher)" |
897 | .IX Item "callback ev_cb (ev_TYPE *watcher)" |
786 | Returns the callback currently set on the watcher. |
898 | Returns the callback currently set on the watcher. |
787 | .IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 |
899 | .IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 |
788 | .IX Item "ev_cb_set (ev_TYPE *watcher, callback)" |
900 | .IX Item "ev_cb_set (ev_TYPE *watcher, callback)" |
789 | Change the callback. You can change the callback at virtually any time |
901 | Change the callback. You can change the callback at virtually any time |
790 | (modulo threads). |
902 | (modulo threads). |
|
|
903 | .IP "ev_set_priority (ev_TYPE *watcher, priority)" 4 |
|
|
904 | .IX Item "ev_set_priority (ev_TYPE *watcher, priority)" |
|
|
905 | .PD 0 |
|
|
906 | .IP "int ev_priority (ev_TYPE *watcher)" 4 |
|
|
907 | .IX Item "int ev_priority (ev_TYPE *watcher)" |
|
|
908 | .PD |
|
|
909 | Set and query the priority of the watcher. The priority is a small |
|
|
910 | integer between \f(CW\*(C`EV_MAXPRI\*(C'\fR (default: \f(CW2\fR) and \f(CW\*(C`EV_MINPRI\*(C'\fR |
|
|
911 | (default: \f(CW\*(C`\-2\*(C'\fR). Pending watchers with higher priority will be invoked |
|
|
912 | before watchers with lower priority, but priority will not keep watchers |
|
|
913 | from being executed (except for \f(CW\*(C`ev_idle\*(C'\fR watchers). |
|
|
914 | .Sp |
|
|
915 | This means that priorities are \fIonly\fR used for ordering callback |
|
|
916 | invocation after new events have been received. This is useful, for |
|
|
917 | example, to reduce latency after idling, or more often, to bind two |
|
|
918 | watchers on the same event and make sure one is called first. |
|
|
919 | .Sp |
|
|
920 | If you need to suppress invocation when higher priority events are pending |
|
|
921 | you need to look at \f(CW\*(C`ev_idle\*(C'\fR watchers, which provide this functionality. |
|
|
922 | .Sp |
|
|
923 | The default priority used by watchers when no priority has been set is |
|
|
924 | always \f(CW0\fR, which is supposed to not be too high and not be too low :). |
|
|
925 | .Sp |
|
|
926 | Setting a priority outside the range of \f(CW\*(C`EV_MINPRI\*(C'\fR to \f(CW\*(C`EV_MAXPRI\*(C'\fR is |
|
|
927 | fine, as long as you do not mind that the priority value you query might |
|
|
928 | or might not have been adjusted to be within valid range. |
791 | .Sh "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0" |
929 | .Sh "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0" |
792 | .IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER" |
930 | .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 |
931 | 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 |
932 | 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 |
933 | to associate arbitrary data with your watcher. If you need more data and |
… | |
… | |
816 | \& struct my_io *w = (struct my_io *)w_; |
954 | \& struct my_io *w = (struct my_io *)w_; |
817 | \& ... |
955 | \& ... |
818 | \& } |
956 | \& } |
819 | .Ve |
957 | .Ve |
820 | .PP |
958 | .PP |
821 | More interesting and less C\-conformant ways of catsing your callback type |
959 | More interesting and less C\-conformant ways of casting your callback type |
822 | have been omitted.... |
960 | instead have been omitted. |
|
|
961 | .PP |
|
|
962 | Another common scenario is having some data structure with multiple |
|
|
963 | watchers: |
|
|
964 | .PP |
|
|
965 | .Vb 6 |
|
|
966 | \& struct my_biggy |
|
|
967 | \& { |
|
|
968 | \& int some_data; |
|
|
969 | \& ev_timer t1; |
|
|
970 | \& ev_timer t2; |
|
|
971 | \& } |
|
|
972 | .Ve |
|
|
973 | .PP |
|
|
974 | In this case getting the pointer to \f(CW\*(C`my_biggy\*(C'\fR is a bit more complicated, |
|
|
975 | you need to use \f(CW\*(C`offsetof\*(C'\fR: |
|
|
976 | .PP |
|
|
977 | .Vb 1 |
|
|
978 | \& #include <stddef.h> |
|
|
979 | .Ve |
|
|
980 | .PP |
|
|
981 | .Vb 6 |
|
|
982 | \& static void |
|
|
983 | \& t1_cb (EV_P_ struct ev_timer *w, int revents) |
|
|
984 | \& { |
|
|
985 | \& struct my_biggy big = (struct my_biggy * |
|
|
986 | \& (((char *)w) - offsetof (struct my_biggy, t1)); |
|
|
987 | \& } |
|
|
988 | .Ve |
|
|
989 | .PP |
|
|
990 | .Vb 6 |
|
|
991 | \& static void |
|
|
992 | \& t2_cb (EV_P_ struct ev_timer *w, int revents) |
|
|
993 | \& { |
|
|
994 | \& struct my_biggy big = (struct my_biggy * |
|
|
995 | \& (((char *)w) - offsetof (struct my_biggy, t2)); |
|
|
996 | \& } |
|
|
997 | .Ve |
823 | .SH "WATCHER TYPES" |
998 | .SH "WATCHER TYPES" |
824 | .IX Header "WATCHER TYPES" |
999 | .IX Header "WATCHER TYPES" |
825 | This section describes each watcher in detail, but will not repeat |
1000 | This section describes each watcher in detail, but will not repeat |
826 | information given in the last section. |
1001 | information given in the last section. Any initialisation/set macros, |
|
|
1002 | functions and members specific to the watcher type are explained. |
|
|
1003 | .PP |
|
|
1004 | Members are additionally marked with either \fI[read\-only]\fR, meaning that, |
|
|
1005 | while the watcher is active, you can look at the member and expect some |
|
|
1006 | sensible content, but you must not modify it (you can modify it while the |
|
|
1007 | watcher is stopped to your hearts content), or \fI[read\-write]\fR, which |
|
|
1008 | means you can expect it to have some sensible content while the watcher |
|
|
1009 | is active, but you can also modify it. Modifying it may not do something |
|
|
1010 | sensible or take immediate effect (or do anything at all), but libev will |
|
|
1011 | not crash or malfunction in any way. |
827 | .ie n .Sh """ev_io"" \- is this file descriptor readable or writable" |
1012 | .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" |
1013 | .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" |
1014 | .IX Subsection "ev_io - is this file descriptor readable or writable?" |
830 | I/O watchers check whether a file descriptor is readable or writable |
1015 | I/O watchers check whether a file descriptor is readable or writable |
831 | in each iteration of the event loop (This behaviour is called |
1016 | in each iteration of the event loop, or, more precisely, when reading |
832 | level-triggering because you keep receiving events as long as the |
1017 | would not block the process and writing would at least be able to write |
833 | condition persists. Remember you can stop the watcher if you don't want to |
1018 | some data. This behaviour is called level-triggering because you keep |
834 | act on the event and neither want to receive future events). |
1019 | receiving events as long as the condition persists. Remember you can stop |
|
|
1020 | the watcher if you don't want to act on the event and neither want to |
|
|
1021 | receive future events. |
835 | .PP |
1022 | .PP |
836 | In general you can register as many read and/or write event watchers per |
1023 | In general you can register as many read and/or write event watchers per |
837 | fd as you want (as long as you don't confuse yourself). Setting all file |
1024 | fd as you want (as long as you don't confuse yourself). Setting all file |
838 | descriptors to non-blocking mode is also usually a good idea (but not |
1025 | descriptors to non-blocking mode is also usually a good idea (but not |
839 | required if you know what you are doing). |
1026 | required if you know what you are doing). |
840 | .PP |
1027 | .PP |
841 | You have to be careful with dup'ed file descriptors, though. Some backends |
1028 | You have to be careful with dup'ed file descriptors, though. Some backends |
842 | (the linux epoll backend is a notable example) cannot handle dup'ed file |
1029 | (the linux epoll backend is a notable example) cannot handle dup'ed file |
843 | descriptors correctly if you register interest in two or more fds pointing |
1030 | descriptors correctly if you register interest in two or more fds pointing |
844 | to the same underlying file/socket etc. description (that is, they share |
1031 | to the same underlying file/socket/etc. description (that is, they share |
845 | the same underlying \*(L"file open\*(R"). |
1032 | the same underlying \*(L"file open\*(R"). |
846 | .PP |
1033 | .PP |
847 | If you must do this, then force the use of a known-to-be-good backend |
1034 | If you must do this, then force the use of a known-to-be-good backend |
848 | (at the time of this writing, this includes only \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR and |
1035 | (at the time of this writing, this includes only \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR and |
849 | \&\f(CW\*(C`EVBACKEND_POLL\*(C'\fR). |
1036 | \&\f(CW\*(C`EVBACKEND_POLL\*(C'\fR). |
|
|
1037 | .PP |
|
|
1038 | Another thing you have to watch out for is that it is quite easy to |
|
|
1039 | receive \*(L"spurious\*(R" readyness notifications, that is your callback might |
|
|
1040 | be called with \f(CW\*(C`EV_READ\*(C'\fR but a subsequent \f(CW\*(C`read\*(C'\fR(2) will actually block |
|
|
1041 | because there is no data. Not only are some backends known to create a |
|
|
1042 | lot of those (for example solaris ports), it is very easy to get into |
|
|
1043 | this situation even with a relatively standard program structure. Thus |
|
|
1044 | it is best to always use non-blocking I/O: An extra \f(CW\*(C`read\*(C'\fR(2) returning |
|
|
1045 | \&\f(CW\*(C`EAGAIN\*(C'\fR is far preferable to a program hanging until some data arrives. |
|
|
1046 | .PP |
|
|
1047 | If you cannot run the fd in non-blocking mode (for example you should not |
|
|
1048 | play around with an Xlib connection), then you have to seperately re-test |
|
|
1049 | whether a file descriptor is really ready with a known-to-be good interface |
|
|
1050 | such as poll (fortunately in our Xlib example, Xlib already does this on |
|
|
1051 | its own, so its quite safe to use). |
850 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
1052 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
851 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
1053 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
852 | .PD 0 |
1054 | .PD 0 |
853 | .IP "ev_io_set (ev_io *, int fd, int events)" 4 |
1055 | .IP "ev_io_set (ev_io *, int fd, int events)" 4 |
854 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
1056 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
855 | .PD |
1057 | .PD |
856 | Configures an \f(CW\*(C`ev_io\*(C'\fR watcher. The fd is the file descriptor to rceeive |
1058 | Configures an \f(CW\*(C`ev_io\*(C'\fR watcher. The \f(CW\*(C`fd\*(C'\fR is the file descriptor to |
857 | events for and events is either \f(CW\*(C`EV_READ\*(C'\fR, \f(CW\*(C`EV_WRITE\*(C'\fR or \f(CW\*(C`EV_READ | |
1059 | rceeive events for and events is either \f(CW\*(C`EV_READ\*(C'\fR, \f(CW\*(C`EV_WRITE\*(C'\fR or |
858 | EV_WRITE\*(C'\fR to receive the given events. |
1060 | \&\f(CW\*(C`EV_READ | EV_WRITE\*(C'\fR to receive the given events. |
859 | .Sp |
1061 | .IP "int fd [read\-only]" 4 |
860 | Please note that most of the more scalable backend mechanisms (for example |
1062 | .IX Item "int fd [read-only]" |
861 | epoll and solaris ports) can result in spurious readyness notifications |
1063 | The file descriptor being watched. |
862 | for file descriptors, so you practically need to use non-blocking I/O (and |
1064 | .IP "int events [read\-only]" 4 |
863 | treat callback invocation as hint only), or retest separately with a safe |
1065 | .IX Item "int events [read-only]" |
864 | interface before doing I/O (XLib can do this), or force the use of either |
1066 | The events being watched. |
865 | \&\f(CW\*(C`EVBACKEND_SELECT\*(C'\fR or \f(CW\*(C`EVBACKEND_POLL\*(C'\fR, which don't suffer from this |
|
|
866 | problem. Also note that it is quite easy to have your callback invoked |
|
|
867 | when the readyness condition is no longer valid even when employing |
|
|
868 | typical ways of handling events, so its a good idea to use non-blocking |
|
|
869 | I/O unconditionally. |
|
|
870 | .PP |
1067 | .PP |
871 | Example: call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well |
1068 | Example: Call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well |
872 | readable, but only once. Since it is likely line\-buffered, you could |
1069 | readable, but only once. Since it is likely line\-buffered, you could |
873 | attempt to read a whole line in the callback: |
1070 | attempt to read a whole line in the callback. |
874 | .PP |
1071 | .PP |
875 | .Vb 6 |
1072 | .Vb 6 |
876 | \& static void |
1073 | \& static void |
877 | \& stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
1074 | \& stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
878 | \& { |
1075 | \& { |
… | |
… | |
887 | \& struct ev_io stdin_readable; |
1084 | \& struct ev_io stdin_readable; |
888 | \& ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ); |
1085 | \& ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ); |
889 | \& ev_io_start (loop, &stdin_readable); |
1086 | \& ev_io_start (loop, &stdin_readable); |
890 | \& ev_loop (loop, 0); |
1087 | \& ev_loop (loop, 0); |
891 | .Ve |
1088 | .Ve |
892 | .ie n .Sh """ev_timer"" \- relative and optionally recurring timeouts" |
1089 | .ie n .Sh """ev_timer"" \- relative and optionally repeating timeouts" |
893 | .el .Sh "\f(CWev_timer\fP \- relative and optionally recurring timeouts" |
1090 | .el .Sh "\f(CWev_timer\fP \- relative and optionally repeating timeouts" |
894 | .IX Subsection "ev_timer - relative and optionally recurring timeouts" |
1091 | .IX Subsection "ev_timer - relative and optionally repeating timeouts" |
895 | Timer watchers are simple relative timers that generate an event after a |
1092 | Timer watchers are simple relative timers that generate an event after a |
896 | given time, and optionally repeating in regular intervals after that. |
1093 | given time, and optionally repeating in regular intervals after that. |
897 | .PP |
1094 | .PP |
898 | The timers are based on real time, that is, if you register an event that |
1095 | The timers are based on real time, that is, if you register an event that |
899 | times out after an hour and you reset your system clock to last years |
1096 | times out after an hour and you reset your system clock to last years |
… | |
… | |
933 | .IP "ev_timer_again (loop)" 4 |
1130 | .IP "ev_timer_again (loop)" 4 |
934 | .IX Item "ev_timer_again (loop)" |
1131 | .IX Item "ev_timer_again (loop)" |
935 | This will act as if the timer timed out and restart it again if it is |
1132 | This will act as if the timer timed out and restart it again if it is |
936 | repeating. The exact semantics are: |
1133 | repeating. The exact semantics are: |
937 | .Sp |
1134 | .Sp |
|
|
1135 | If the timer is pending, its pending status is cleared. |
|
|
1136 | .Sp |
938 | If the timer is started but nonrepeating, stop it. |
1137 | If the timer is started but nonrepeating, stop it (as if it timed out). |
939 | .Sp |
1138 | .Sp |
940 | If the timer is repeating, either start it if necessary (with the repeat |
1139 | If the timer is repeating, either start it if necessary (with the |
941 | value), or reset the running timer to the repeat value. |
1140 | \&\f(CW\*(C`repeat\*(C'\fR value), or reset the running timer to the \f(CW\*(C`repeat\*(C'\fR value. |
942 | .Sp |
1141 | .Sp |
943 | This sounds a bit complicated, but here is a useful and typical |
1142 | This sounds a bit complicated, but here is a useful and typical |
944 | example: Imagine you have a tcp connection and you want a so-called idle |
1143 | example: Imagine you have a tcp connection and you want a so-called idle |
945 | timeout, that is, you want to be called when there have been, say, 60 |
1144 | timeout, that is, you want to be called when there have been, say, 60 |
946 | seconds of inactivity on the socket. The easiest way to do this is to |
1145 | seconds of inactivity on the socket. The easiest way to do this is to |
947 | configure an \f(CW\*(C`ev_timer\*(C'\fR with after=repeat=60 and calling ev_timer_again each |
1146 | configure an \f(CW\*(C`ev_timer\*(C'\fR with a \f(CW\*(C`repeat\*(C'\fR value of \f(CW60\fR and then call |
948 | time you successfully read or write some data. If you go into an idle |
1147 | \&\f(CW\*(C`ev_timer_again\*(C'\fR each time you successfully read or write some data. If |
949 | state where you do not expect data to travel on the socket, you can stop |
1148 | you go into an idle state where you do not expect data to travel on the |
950 | the timer, and again will automatically restart it if need be. |
1149 | socket, you can \f(CW\*(C`ev_timer_stop\*(C'\fR the timer, and \f(CW\*(C`ev_timer_again\*(C'\fR will |
|
|
1150 | automatically restart it if need be. |
|
|
1151 | .Sp |
|
|
1152 | That means you can ignore the \f(CW\*(C`after\*(C'\fR value and \f(CW\*(C`ev_timer_start\*(C'\fR |
|
|
1153 | altogether and only ever use the \f(CW\*(C`repeat\*(C'\fR value and \f(CW\*(C`ev_timer_again\*(C'\fR: |
|
|
1154 | .Sp |
|
|
1155 | .Vb 8 |
|
|
1156 | \& ev_timer_init (timer, callback, 0., 5.); |
|
|
1157 | \& ev_timer_again (loop, timer); |
|
|
1158 | \& ... |
|
|
1159 | \& timer->again = 17.; |
|
|
1160 | \& ev_timer_again (loop, timer); |
|
|
1161 | \& ... |
|
|
1162 | \& timer->again = 10.; |
|
|
1163 | \& ev_timer_again (loop, timer); |
|
|
1164 | .Ve |
|
|
1165 | .Sp |
|
|
1166 | This is more slightly efficient then stopping/starting the timer each time |
|
|
1167 | you want to modify its timeout value. |
|
|
1168 | .IP "ev_tstamp repeat [read\-write]" 4 |
|
|
1169 | .IX Item "ev_tstamp repeat [read-write]" |
|
|
1170 | The current \f(CW\*(C`repeat\*(C'\fR value. Will be used each time the watcher times out |
|
|
1171 | or \f(CW\*(C`ev_timer_again\*(C'\fR is called and determines the next timeout (if any), |
|
|
1172 | which is also when any modifications are taken into account. |
951 | .PP |
1173 | .PP |
952 | Example: create a timer that fires after 60 seconds. |
1174 | Example: Create a timer that fires after 60 seconds. |
953 | .PP |
1175 | .PP |
954 | .Vb 5 |
1176 | .Vb 5 |
955 | \& static void |
1177 | \& static void |
956 | \& one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1178 | \& one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
957 | \& { |
1179 | \& { |
… | |
… | |
963 | \& struct ev_timer mytimer; |
1185 | \& struct ev_timer mytimer; |
964 | \& ev_timer_init (&mytimer, one_minute_cb, 60., 0.); |
1186 | \& ev_timer_init (&mytimer, one_minute_cb, 60., 0.); |
965 | \& ev_timer_start (loop, &mytimer); |
1187 | \& ev_timer_start (loop, &mytimer); |
966 | .Ve |
1188 | .Ve |
967 | .PP |
1189 | .PP |
968 | Example: create a timeout timer that times out after 10 seconds of |
1190 | Example: Create a timeout timer that times out after 10 seconds of |
969 | inactivity. |
1191 | inactivity. |
970 | .PP |
1192 | .PP |
971 | .Vb 5 |
1193 | .Vb 5 |
972 | \& static void |
1194 | \& static void |
973 | \& timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1195 | \& timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
… | |
… | |
986 | .Vb 3 |
1208 | .Vb 3 |
987 | \& // and in some piece of code that gets executed on any "activity": |
1209 | \& // and in some piece of code that gets executed on any "activity": |
988 | \& // reset the timeout to start ticking again at 10 seconds |
1210 | \& // reset the timeout to start ticking again at 10 seconds |
989 | \& ev_timer_again (&mytimer); |
1211 | \& ev_timer_again (&mytimer); |
990 | .Ve |
1212 | .Ve |
991 | .ie n .Sh """ev_periodic"" \- to cron or not to cron" |
1213 | .ie n .Sh """ev_periodic"" \- to cron or not to cron?" |
992 | .el .Sh "\f(CWev_periodic\fP \- to cron or not to cron" |
1214 | .el .Sh "\f(CWev_periodic\fP \- to cron or not to cron?" |
993 | .IX Subsection "ev_periodic - to cron or not to cron" |
1215 | .IX Subsection "ev_periodic - to cron or not to cron?" |
994 | Periodic watchers are also timers of a kind, but they are very versatile |
1216 | Periodic watchers are also timers of a kind, but they are very versatile |
995 | (and unfortunately a bit complex). |
1217 | (and unfortunately a bit complex). |
996 | .PP |
1218 | .PP |
997 | Unlike \f(CW\*(C`ev_timer\*(C'\fR's, they are not based on real time (or relative time) |
1219 | Unlike \f(CW\*(C`ev_timer\*(C'\fR's, they are not based on real time (or relative time) |
998 | but on wallclock time (absolute time). You can tell a periodic watcher |
1220 | but on wallclock time (absolute time). You can tell a periodic watcher |
999 | to trigger \*(L"at\*(R" some specific point in time. For example, if you tell a |
1221 | to trigger \*(L"at\*(R" some specific point in time. For example, if you tell a |
1000 | periodic watcher to trigger in 10 seconds (by specifiying e.g. c<ev_now () |
1222 | periodic watcher to trigger in 10 seconds (by specifiying e.g. \f(CW\*(C`ev_now () |
1001 | + 10.>) and then reset your system clock to the last year, then it will |
1223 | + 10.\*(C'\fR) and then reset your system clock to the last year, then it will |
1002 | take a year to trigger the event (unlike an \f(CW\*(C`ev_timer\*(C'\fR, which would trigger |
1224 | take a year to trigger the event (unlike an \f(CW\*(C`ev_timer\*(C'\fR, which would trigger |
1003 | roughly 10 seconds later and of course not if you reset your system time |
1225 | roughly 10 seconds later and of course not if you reset your system time |
1004 | again). |
1226 | again). |
1005 | .PP |
1227 | .PP |
1006 | They can also be used to implement vastly more complex timers, such as |
1228 | They can also be used to implement vastly more complex timers, such as |
… | |
… | |
1087 | .IX Item "ev_periodic_again (loop, ev_periodic *)" |
1309 | .IX Item "ev_periodic_again (loop, ev_periodic *)" |
1088 | Simply stops and restarts the periodic watcher again. This is only useful |
1310 | Simply stops and restarts the periodic watcher again. This is only useful |
1089 | when you changed some parameters or the reschedule callback would return |
1311 | when you changed some parameters or the reschedule callback would return |
1090 | a different time than the last time it was called (e.g. in a crond like |
1312 | a different time than the last time it was called (e.g. in a crond like |
1091 | program when the crontabs have changed). |
1313 | program when the crontabs have changed). |
|
|
1314 | .IP "ev_tstamp interval [read\-write]" 4 |
|
|
1315 | .IX Item "ev_tstamp interval [read-write]" |
|
|
1316 | The current interval value. Can be modified any time, but changes only |
|
|
1317 | take effect when the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being |
|
|
1318 | called. |
|
|
1319 | .IP "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read\-write]" 4 |
|
|
1320 | .IX Item "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write]" |
|
|
1321 | The current reschedule callback, or \f(CW0\fR, if this functionality is |
|
|
1322 | switched off. Can be changed any time, but changes only take effect when |
|
|
1323 | the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called. |
1092 | .PP |
1324 | .PP |
1093 | Example: call a callback every hour, or, more precisely, whenever the |
1325 | Example: Call a callback every hour, or, more precisely, whenever the |
1094 | system clock is divisible by 3600. The callback invocation times have |
1326 | system clock is divisible by 3600. The callback invocation times have |
1095 | potentially a lot of jittering, but good long-term stability. |
1327 | potentially a lot of jittering, but good long-term stability. |
1096 | .PP |
1328 | .PP |
1097 | .Vb 5 |
1329 | .Vb 5 |
1098 | \& static void |
1330 | \& static void |
… | |
… | |
1106 | \& struct ev_periodic hourly_tick; |
1338 | \& struct ev_periodic hourly_tick; |
1107 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); |
1339 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); |
1108 | \& ev_periodic_start (loop, &hourly_tick); |
1340 | \& ev_periodic_start (loop, &hourly_tick); |
1109 | .Ve |
1341 | .Ve |
1110 | .PP |
1342 | .PP |
1111 | Example: the same as above, but use a reschedule callback to do it: |
1343 | Example: The same as above, but use a reschedule callback to do it: |
1112 | .PP |
1344 | .PP |
1113 | .Vb 1 |
1345 | .Vb 1 |
1114 | \& #include <math.h> |
1346 | \& #include <math.h> |
1115 | .Ve |
1347 | .Ve |
1116 | .PP |
1348 | .PP |
… | |
… | |
1124 | .PP |
1356 | .PP |
1125 | .Vb 1 |
1357 | .Vb 1 |
1126 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); |
1358 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); |
1127 | .Ve |
1359 | .Ve |
1128 | .PP |
1360 | .PP |
1129 | Example: call a callback every hour, starting now: |
1361 | Example: Call a callback every hour, starting now: |
1130 | .PP |
1362 | .PP |
1131 | .Vb 4 |
1363 | .Vb 4 |
1132 | \& struct ev_periodic hourly_tick; |
1364 | \& struct ev_periodic hourly_tick; |
1133 | \& ev_periodic_init (&hourly_tick, clock_cb, |
1365 | \& ev_periodic_init (&hourly_tick, clock_cb, |
1134 | \& fmod (ev_now (loop), 3600.), 3600., 0); |
1366 | \& fmod (ev_now (loop), 3600.), 3600., 0); |
1135 | \& ev_periodic_start (loop, &hourly_tick); |
1367 | \& ev_periodic_start (loop, &hourly_tick); |
1136 | .Ve |
1368 | .Ve |
1137 | .ie n .Sh """ev_signal"" \- signal me when a signal gets signalled" |
1369 | .ie n .Sh """ev_signal"" \- signal me when a signal gets signalled!" |
1138 | .el .Sh "\f(CWev_signal\fP \- signal me when a signal gets signalled" |
1370 | .el .Sh "\f(CWev_signal\fP \- signal me when a signal gets signalled!" |
1139 | .IX Subsection "ev_signal - signal me when a signal gets signalled" |
1371 | .IX Subsection "ev_signal - signal me when a signal gets signalled!" |
1140 | Signal watchers will trigger an event when the process receives a specific |
1372 | Signal watchers will trigger an event when the process receives a specific |
1141 | signal one or more times. Even though signals are very asynchronous, libev |
1373 | signal one or more times. Even though signals are very asynchronous, libev |
1142 | will try it's best to deliver signals synchronously, i.e. as part of the |
1374 | will try it's best to deliver signals synchronously, i.e. as part of the |
1143 | normal event processing, like any other event. |
1375 | normal event processing, like any other event. |
1144 | .PP |
1376 | .PP |
… | |
… | |
1154 | .IP "ev_signal_set (ev_signal *, int signum)" 4 |
1386 | .IP "ev_signal_set (ev_signal *, int signum)" 4 |
1155 | .IX Item "ev_signal_set (ev_signal *, int signum)" |
1387 | .IX Item "ev_signal_set (ev_signal *, int signum)" |
1156 | .PD |
1388 | .PD |
1157 | Configures the watcher to trigger on the given signal number (usually one |
1389 | Configures the watcher to trigger on the given signal number (usually one |
1158 | of the \f(CW\*(C`SIGxxx\*(C'\fR constants). |
1390 | of the \f(CW\*(C`SIGxxx\*(C'\fR constants). |
|
|
1391 | .IP "int signum [read\-only]" 4 |
|
|
1392 | .IX Item "int signum [read-only]" |
|
|
1393 | The signal the watcher watches out for. |
1159 | .ie n .Sh """ev_child"" \- wait for pid status changes" |
1394 | .ie n .Sh """ev_child"" \- watch out for process status changes" |
1160 | .el .Sh "\f(CWev_child\fP \- wait for pid status changes" |
1395 | .el .Sh "\f(CWev_child\fP \- watch out for process status changes" |
1161 | .IX Subsection "ev_child - wait for pid status changes" |
1396 | .IX Subsection "ev_child - watch out for process status changes" |
1162 | Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to |
1397 | Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to |
1163 | some child status changes (most typically when a child of yours dies). |
1398 | some child status changes (most typically when a child of yours dies). |
1164 | .IP "ev_child_init (ev_child *, callback, int pid)" 4 |
1399 | .IP "ev_child_init (ev_child *, callback, int pid)" 4 |
1165 | .IX Item "ev_child_init (ev_child *, callback, int pid)" |
1400 | .IX Item "ev_child_init (ev_child *, callback, int pid)" |
1166 | .PD 0 |
1401 | .PD 0 |
… | |
… | |
1171 | \&\fIany\fR process if \f(CW\*(C`pid\*(C'\fR is specified as \f(CW0\fR). The callback can look |
1406 | \&\fIany\fR process if \f(CW\*(C`pid\*(C'\fR is specified as \f(CW0\fR). The callback can look |
1172 | at the \f(CW\*(C`rstatus\*(C'\fR member of the \f(CW\*(C`ev_child\*(C'\fR watcher structure to see |
1407 | at the \f(CW\*(C`rstatus\*(C'\fR member of the \f(CW\*(C`ev_child\*(C'\fR watcher structure to see |
1173 | the status word (use the macros from \f(CW\*(C`sys/wait.h\*(C'\fR and see your systems |
1408 | the status word (use the macros from \f(CW\*(C`sys/wait.h\*(C'\fR and see your systems |
1174 | \&\f(CW\*(C`waitpid\*(C'\fR documentation). The \f(CW\*(C`rpid\*(C'\fR member contains the pid of the |
1409 | \&\f(CW\*(C`waitpid\*(C'\fR documentation). The \f(CW\*(C`rpid\*(C'\fR member contains the pid of the |
1175 | process causing the status change. |
1410 | process causing the status change. |
|
|
1411 | .IP "int pid [read\-only]" 4 |
|
|
1412 | .IX Item "int pid [read-only]" |
|
|
1413 | The process id this watcher watches out for, or \f(CW0\fR, meaning any process id. |
|
|
1414 | .IP "int rpid [read\-write]" 4 |
|
|
1415 | .IX Item "int rpid [read-write]" |
|
|
1416 | The process id that detected a status change. |
|
|
1417 | .IP "int rstatus [read\-write]" 4 |
|
|
1418 | .IX Item "int rstatus [read-write]" |
|
|
1419 | The process exit/trace status caused by \f(CW\*(C`rpid\*(C'\fR (see your systems |
|
|
1420 | \&\f(CW\*(C`waitpid\*(C'\fR and \f(CW\*(C`sys/wait.h\*(C'\fR documentation for details). |
1176 | .PP |
1421 | .PP |
1177 | Example: try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0. |
1422 | Example: Try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0. |
1178 | .PP |
1423 | .PP |
1179 | .Vb 5 |
1424 | .Vb 5 |
1180 | \& static void |
1425 | \& static void |
1181 | \& sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
1426 | \& sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
1182 | \& { |
1427 | \& { |
… | |
… | |
1187 | .Vb 3 |
1432 | .Vb 3 |
1188 | \& struct ev_signal signal_watcher; |
1433 | \& struct ev_signal signal_watcher; |
1189 | \& ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
1434 | \& ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
1190 | \& ev_signal_start (loop, &sigint_cb); |
1435 | \& ev_signal_start (loop, &sigint_cb); |
1191 | .Ve |
1436 | .Ve |
|
|
1437 | .ie n .Sh """ev_stat"" \- did the file attributes just change?" |
|
|
1438 | .el .Sh "\f(CWev_stat\fP \- did the file attributes just change?" |
|
|
1439 | .IX Subsection "ev_stat - did the file attributes just change?" |
|
|
1440 | This watches a filesystem path for attribute changes. That is, it calls |
|
|
1441 | \&\f(CW\*(C`stat\*(C'\fR regularly (or when the \s-1OS\s0 says it changed) and sees if it changed |
|
|
1442 | compared to the last time, invoking the callback if it did. |
|
|
1443 | .PP |
|
|
1444 | The path does not need to exist: changing from \*(L"path exists\*(R" to \*(L"path does |
|
|
1445 | not exist\*(R" is a status change like any other. The condition \*(L"path does |
|
|
1446 | not exist\*(R" is signified by the \f(CW\*(C`st_nlink\*(C'\fR field being zero (which is |
|
|
1447 | otherwise always forced to be at least one) and all the other fields of |
|
|
1448 | the stat buffer having unspecified contents. |
|
|
1449 | .PP |
|
|
1450 | The path \fIshould\fR be absolute and \fImust not\fR end in a slash. If it is |
|
|
1451 | relative and your working directory changes, the behaviour is undefined. |
|
|
1452 | .PP |
|
|
1453 | Since there is no standard to do this, the portable implementation simply |
|
|
1454 | calls \f(CW\*(C`stat (2)\*(C'\fR regularly on the path to see if it changed somehow. You |
|
|
1455 | can specify a recommended polling interval for this case. If you specify |
|
|
1456 | a polling interval of \f(CW0\fR (highly recommended!) then a \fIsuitable, |
|
|
1457 | unspecified default\fR value will be used (which you can expect to be around |
|
|
1458 | five seconds, although this might change dynamically). Libev will also |
|
|
1459 | impose a minimum interval which is currently around \f(CW0.1\fR, but thats |
|
|
1460 | usually overkill. |
|
|
1461 | .PP |
|
|
1462 | This watcher type is not meant for massive numbers of stat watchers, |
|
|
1463 | as even with OS-supported change notifications, this can be |
|
|
1464 | resource\-intensive. |
|
|
1465 | .PP |
|
|
1466 | At the time of this writing, only the Linux inotify interface is |
|
|
1467 | implemented (implementing kqueue support is left as an exercise for the |
|
|
1468 | reader). Inotify will be used to give hints only and should not change the |
|
|
1469 | semantics of \f(CW\*(C`ev_stat\*(C'\fR watchers, which means that libev sometimes needs |
|
|
1470 | to fall back to regular polling again even with inotify, but changes are |
|
|
1471 | usually detected immediately, and if the file exists there will be no |
|
|
1472 | polling. |
|
|
1473 | .IP "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" 4 |
|
|
1474 | .IX Item "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" |
|
|
1475 | .PD 0 |
|
|
1476 | .IP "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" 4 |
|
|
1477 | .IX Item "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" |
|
|
1478 | .PD |
|
|
1479 | Configures the watcher to wait for status changes of the given |
|
|
1480 | \&\f(CW\*(C`path\*(C'\fR. The \f(CW\*(C`interval\*(C'\fR is a hint on how quickly a change is expected to |
|
|
1481 | be detected and should normally be specified as \f(CW0\fR to let libev choose |
|
|
1482 | a suitable value. The memory pointed to by \f(CW\*(C`path\*(C'\fR must point to the same |
|
|
1483 | path for as long as the watcher is active. |
|
|
1484 | .Sp |
|
|
1485 | The callback will be receive \f(CW\*(C`EV_STAT\*(C'\fR when a change was detected, |
|
|
1486 | relative to the attributes at the time the watcher was started (or the |
|
|
1487 | last change was detected). |
|
|
1488 | .IP "ev_stat_stat (ev_stat *)" 4 |
|
|
1489 | .IX Item "ev_stat_stat (ev_stat *)" |
|
|
1490 | Updates the stat buffer immediately with new values. If you change the |
|
|
1491 | watched path in your callback, you could call this fucntion to avoid |
|
|
1492 | detecting this change (while introducing a race condition). Can also be |
|
|
1493 | useful simply to find out the new values. |
|
|
1494 | .IP "ev_statdata attr [read\-only]" 4 |
|
|
1495 | .IX Item "ev_statdata attr [read-only]" |
|
|
1496 | The most-recently detected attributes of the file. Although the type is of |
|
|
1497 | \&\f(CW\*(C`ev_statdata\*(C'\fR, this is usually the (or one of the) \f(CW\*(C`struct stat\*(C'\fR types |
|
|
1498 | suitable for your system. If the \f(CW\*(C`st_nlink\*(C'\fR member is \f(CW0\fR, then there |
|
|
1499 | was some error while \f(CW\*(C`stat\*(C'\fRing the file. |
|
|
1500 | .IP "ev_statdata prev [read\-only]" 4 |
|
|
1501 | .IX Item "ev_statdata prev [read-only]" |
|
|
1502 | The previous attributes of the file. The callback gets invoked whenever |
|
|
1503 | \&\f(CW\*(C`prev\*(C'\fR != \f(CW\*(C`attr\*(C'\fR. |
|
|
1504 | .IP "ev_tstamp interval [read\-only]" 4 |
|
|
1505 | .IX Item "ev_tstamp interval [read-only]" |
|
|
1506 | The specified interval. |
|
|
1507 | .IP "const char *path [read\-only]" 4 |
|
|
1508 | .IX Item "const char *path [read-only]" |
|
|
1509 | The filesystem path that is being watched. |
|
|
1510 | .PP |
|
|
1511 | Example: Watch \f(CW\*(C`/etc/passwd\*(C'\fR for attribute changes. |
|
|
1512 | .PP |
|
|
1513 | .Vb 15 |
|
|
1514 | \& static void |
|
|
1515 | \& passwd_cb (struct ev_loop *loop, ev_stat *w, int revents) |
|
|
1516 | \& { |
|
|
1517 | \& /* /etc/passwd changed in some way */ |
|
|
1518 | \& if (w->attr.st_nlink) |
|
|
1519 | \& { |
|
|
1520 | \& printf ("passwd current size %ld\en", (long)w->attr.st_size); |
|
|
1521 | \& printf ("passwd current atime %ld\en", (long)w->attr.st_mtime); |
|
|
1522 | \& printf ("passwd current mtime %ld\en", (long)w->attr.st_mtime); |
|
|
1523 | \& } |
|
|
1524 | \& else |
|
|
1525 | \& /* you shalt not abuse printf for puts */ |
|
|
1526 | \& puts ("wow, /etc/passwd is not there, expect problems. " |
|
|
1527 | \& "if this is windows, they already arrived\en"); |
|
|
1528 | \& } |
|
|
1529 | .Ve |
|
|
1530 | .PP |
|
|
1531 | .Vb 2 |
|
|
1532 | \& ... |
|
|
1533 | \& ev_stat passwd; |
|
|
1534 | .Ve |
|
|
1535 | .PP |
|
|
1536 | .Vb 2 |
|
|
1537 | \& ev_stat_init (&passwd, passwd_cb, "/etc/passwd"); |
|
|
1538 | \& ev_stat_start (loop, &passwd); |
|
|
1539 | .Ve |
1192 | .ie n .Sh """ev_idle"" \- when you've got nothing better to do" |
1540 | .ie n .Sh """ev_idle"" \- when you've got nothing better to do..." |
1193 | .el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do" |
1541 | .el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do..." |
1194 | .IX Subsection "ev_idle - when you've got nothing better to do" |
1542 | .IX Subsection "ev_idle - when you've got nothing better to do..." |
1195 | Idle watchers trigger events when there are no other events are pending |
1543 | Idle watchers trigger events when no other events of the same or higher |
1196 | (prepare, check and other idle watchers do not count). That is, as long |
1544 | priority are pending (prepare, check and other idle watchers do not |
1197 | as your process is busy handling sockets or timeouts (or even signals, |
1545 | count). |
1198 | imagine) it will not be triggered. But when your process is idle all idle |
1546 | .PP |
1199 | watchers are being called again and again, once per event loop iteration \- |
1547 | That is, as long as your process is busy handling sockets or timeouts |
|
|
1548 | (or even signals, imagine) of the same or higher priority it will not be |
|
|
1549 | triggered. But when your process is idle (or only lower-priority watchers |
|
|
1550 | are pending), the idle watchers are being called once per event loop |
1200 | until stopped, that is, or your process receives more events and becomes |
1551 | iteration \- until stopped, that is, or your process receives more events |
1201 | busy. |
1552 | and becomes busy again with higher priority stuff. |
1202 | .PP |
1553 | .PP |
1203 | The most noteworthy effect is that as long as any idle watchers are |
1554 | The most noteworthy effect is that as long as any idle watchers are |
1204 | active, the process will not block when waiting for new events. |
1555 | active, the process will not block when waiting for new events. |
1205 | .PP |
1556 | .PP |
1206 | Apart from keeping your process non-blocking (which is a useful |
1557 | Apart from keeping your process non-blocking (which is a useful |
… | |
… | |
1211 | .IX Item "ev_idle_init (ev_signal *, callback)" |
1562 | .IX Item "ev_idle_init (ev_signal *, callback)" |
1212 | Initialises and configures the idle watcher \- it has no parameters of any |
1563 | Initialises and configures the idle watcher \- it has no parameters of any |
1213 | kind. There is a \f(CW\*(C`ev_idle_set\*(C'\fR macro, but using it is utterly pointless, |
1564 | kind. There is a \f(CW\*(C`ev_idle_set\*(C'\fR macro, but using it is utterly pointless, |
1214 | believe me. |
1565 | believe me. |
1215 | .PP |
1566 | .PP |
1216 | Example: dynamically allocate an \f(CW\*(C`ev_idle\*(C'\fR, start it, and in the |
1567 | Example: Dynamically allocate an \f(CW\*(C`ev_idle\*(C'\fR watcher, start it, and in the |
1217 | callback, free it. Alos, use no error checking, as usual. |
1568 | callback, free it. Also, use no error checking, as usual. |
1218 | .PP |
1569 | .PP |
1219 | .Vb 7 |
1570 | .Vb 7 |
1220 | \& static void |
1571 | \& static void |
1221 | \& idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
1572 | \& idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
1222 | \& { |
1573 | \& { |
… | |
… | |
1229 | .Vb 3 |
1580 | .Vb 3 |
1230 | \& struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle)); |
1581 | \& struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle)); |
1231 | \& ev_idle_init (idle_watcher, idle_cb); |
1582 | \& ev_idle_init (idle_watcher, idle_cb); |
1232 | \& ev_idle_start (loop, idle_cb); |
1583 | \& ev_idle_start (loop, idle_cb); |
1233 | .Ve |
1584 | .Ve |
1234 | .ie n .Sh """ev_prepare""\fP and \f(CW""ev_check"" \- customise your event loop" |
1585 | .ie n .Sh """ev_prepare""\fP and \f(CW""ev_check"" \- customise your event loop!" |
1235 | .el .Sh "\f(CWev_prepare\fP and \f(CWev_check\fP \- customise your event loop" |
1586 | .el .Sh "\f(CWev_prepare\fP and \f(CWev_check\fP \- customise your event loop!" |
1236 | .IX Subsection "ev_prepare and ev_check - customise your event loop" |
1587 | .IX Subsection "ev_prepare and ev_check - customise your event loop!" |
1237 | Prepare and check watchers are usually (but not always) used in tandem: |
1588 | Prepare and check watchers are usually (but not always) used in tandem: |
1238 | prepare watchers get invoked before the process blocks and check watchers |
1589 | prepare watchers get invoked before the process blocks and check watchers |
1239 | afterwards. |
1590 | afterwards. |
1240 | .PP |
1591 | .PP |
|
|
1592 | You \fImust not\fR call \f(CW\*(C`ev_loop\*(C'\fR or similar functions that enter |
|
|
1593 | the current event loop from either \f(CW\*(C`ev_prepare\*(C'\fR or \f(CW\*(C`ev_check\*(C'\fR |
|
|
1594 | watchers. Other loops than the current one are fine, however. The |
|
|
1595 | rationale behind this is that you do not need to check for recursion in |
|
|
1596 | those watchers, i.e. the sequence will always be \f(CW\*(C`ev_prepare\*(C'\fR, blocking, |
|
|
1597 | \&\f(CW\*(C`ev_check\*(C'\fR so if you have one watcher of each kind they will always be |
|
|
1598 | called in pairs bracketing the blocking call. |
|
|
1599 | .PP |
1241 | Their main purpose is to integrate other event mechanisms into libev and |
1600 | Their main purpose is to integrate other event mechanisms into libev and |
1242 | their use is somewhat advanced. This could be used, for example, to track |
1601 | their use is somewhat advanced. This could be used, for example, to track |
1243 | variable changes, implement your own watchers, integrate net-snmp or a |
1602 | variable changes, implement your own watchers, integrate net-snmp or a |
1244 | coroutine library and lots more. |
1603 | coroutine library and lots more. They are also occasionally useful if |
|
|
1604 | you cache some data and want to flush it before blocking (for example, |
|
|
1605 | in X programs you might want to do an \f(CW\*(C`XFlush ()\*(C'\fR in an \f(CW\*(C`ev_prepare\*(C'\fR |
|
|
1606 | watcher). |
1245 | .PP |
1607 | .PP |
1246 | This is done by examining in each prepare call which file descriptors need |
1608 | This is done by examining in each prepare call which file descriptors need |
1247 | to be watched by the other library, registering \f(CW\*(C`ev_io\*(C'\fR watchers for |
1609 | to be watched by the other library, registering \f(CW\*(C`ev_io\*(C'\fR watchers for |
1248 | them and starting an \f(CW\*(C`ev_timer\*(C'\fR watcher for any timeouts (many libraries |
1610 | them and starting an \f(CW\*(C`ev_timer\*(C'\fR watcher for any timeouts (many libraries |
1249 | provide just this functionality). Then, in the check watcher you check for |
1611 | provide just this functionality). Then, in the check watcher you check for |
… | |
… | |
1268 | .PD |
1630 | .PD |
1269 | Initialises and configures the prepare or check watcher \- they have no |
1631 | Initialises and configures the prepare or check watcher \- they have no |
1270 | parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR |
1632 | parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR |
1271 | macros, but using them is utterly, utterly and completely pointless. |
1633 | macros, but using them is utterly, utterly and completely pointless. |
1272 | .PP |
1634 | .PP |
1273 | Example: *TODO*. |
1635 | Example: To include a library such as adns, you would add \s-1IO\s0 watchers |
|
|
1636 | and a timeout watcher in a prepare handler, as required by libadns, and |
|
|
1637 | in a check watcher, destroy them and call into libadns. What follows is |
|
|
1638 | pseudo-code only of course: |
|
|
1639 | .PP |
|
|
1640 | .Vb 2 |
|
|
1641 | \& static ev_io iow [nfd]; |
|
|
1642 | \& static ev_timer tw; |
|
|
1643 | .Ve |
|
|
1644 | .PP |
|
|
1645 | .Vb 9 |
|
|
1646 | \& static void |
|
|
1647 | \& io_cb (ev_loop *loop, ev_io *w, int revents) |
|
|
1648 | \& { |
|
|
1649 | \& // set the relevant poll flags |
|
|
1650 | \& // could also call adns_processreadable etc. here |
|
|
1651 | \& struct pollfd *fd = (struct pollfd *)w->data; |
|
|
1652 | \& if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
|
|
1653 | \& if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
|
|
1654 | \& } |
|
|
1655 | .Ve |
|
|
1656 | .PP |
|
|
1657 | .Vb 8 |
|
|
1658 | \& // create io watchers for each fd and a timer before blocking |
|
|
1659 | \& static void |
|
|
1660 | \& adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
|
|
1661 | \& { |
|
|
1662 | \& int timeout = 3600000; |
|
|
1663 | \& struct pollfd fds [nfd]; |
|
|
1664 | \& // actual code will need to loop here and realloc etc. |
|
|
1665 | \& adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
|
|
1666 | .Ve |
|
|
1667 | .PP |
|
|
1668 | .Vb 3 |
|
|
1669 | \& /* the callback is illegal, but won't be called as we stop during check */ |
|
|
1670 | \& ev_timer_init (&tw, 0, timeout * 1e-3); |
|
|
1671 | \& ev_timer_start (loop, &tw); |
|
|
1672 | .Ve |
|
|
1673 | .PP |
|
|
1674 | .Vb 6 |
|
|
1675 | \& // create on ev_io per pollfd |
|
|
1676 | \& for (int i = 0; i < nfd; ++i) |
|
|
1677 | \& { |
|
|
1678 | \& ev_io_init (iow + i, io_cb, fds [i].fd, |
|
|
1679 | \& ((fds [i].events & POLLIN ? EV_READ : 0) |
|
|
1680 | \& | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
|
|
1681 | .Ve |
|
|
1682 | .PP |
|
|
1683 | .Vb 5 |
|
|
1684 | \& fds [i].revents = 0; |
|
|
1685 | \& iow [i].data = fds + i; |
|
|
1686 | \& ev_io_start (loop, iow + i); |
|
|
1687 | \& } |
|
|
1688 | \& } |
|
|
1689 | .Ve |
|
|
1690 | .PP |
|
|
1691 | .Vb 5 |
|
|
1692 | \& // stop all watchers after blocking |
|
|
1693 | \& static void |
|
|
1694 | \& adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
|
|
1695 | \& { |
|
|
1696 | \& ev_timer_stop (loop, &tw); |
|
|
1697 | .Ve |
|
|
1698 | .PP |
|
|
1699 | .Vb 2 |
|
|
1700 | \& for (int i = 0; i < nfd; ++i) |
|
|
1701 | \& ev_io_stop (loop, iow + i); |
|
|
1702 | .Ve |
|
|
1703 | .PP |
|
|
1704 | .Vb 2 |
|
|
1705 | \& adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
|
|
1706 | \& } |
|
|
1707 | .Ve |
1274 | .ie n .Sh """ev_embed"" \- when one backend isn't enough" |
1708 | .ie n .Sh """ev_embed"" \- when one backend isn't enough..." |
1275 | .el .Sh "\f(CWev_embed\fP \- when one backend isn't enough" |
1709 | .el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..." |
1276 | .IX Subsection "ev_embed - when one backend isn't enough" |
1710 | .IX Subsection "ev_embed - when one backend isn't enough..." |
1277 | This is a rather advanced watcher type that lets you embed one event loop |
1711 | This is a rather advanced watcher type that lets you embed one event loop |
1278 | into another (currently only \f(CW\*(C`ev_io\*(C'\fR events are supported in the embedded |
1712 | into another (currently only \f(CW\*(C`ev_io\*(C'\fR events are supported in the embedded |
1279 | loop, other types of watchers might be handled in a delayed or incorrect |
1713 | loop, other types of watchers might be handled in a delayed or incorrect |
1280 | fashion and must not be used). |
1714 | fashion and must not be used). |
1281 | .PP |
1715 | .PP |
… | |
… | |
1361 | .IP "ev_embed_sweep (loop, ev_embed *)" 4 |
1795 | .IP "ev_embed_sweep (loop, ev_embed *)" 4 |
1362 | .IX Item "ev_embed_sweep (loop, ev_embed *)" |
1796 | .IX Item "ev_embed_sweep (loop, ev_embed *)" |
1363 | Make a single, non-blocking sweep over the embedded loop. This works |
1797 | Make a single, non-blocking sweep over the embedded loop. This works |
1364 | similarly to \f(CW\*(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\*(C'\fR, but in the most |
1798 | similarly to \f(CW\*(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\*(C'\fR, but in the most |
1365 | apropriate way for embedded loops. |
1799 | apropriate way for embedded loops. |
|
|
1800 | .IP "struct ev_loop *loop [read\-only]" 4 |
|
|
1801 | .IX Item "struct ev_loop *loop [read-only]" |
|
|
1802 | The embedded event loop. |
|
|
1803 | .ie n .Sh """ev_fork"" \- the audacity to resume the event loop after a fork" |
|
|
1804 | .el .Sh "\f(CWev_fork\fP \- the audacity to resume the event loop after a fork" |
|
|
1805 | .IX Subsection "ev_fork - the audacity to resume the event loop after a fork" |
|
|
1806 | Fork watchers are called when a \f(CW\*(C`fork ()\*(C'\fR was detected (usually because |
|
|
1807 | whoever is a good citizen cared to tell libev about it by calling |
|
|
1808 | \&\f(CW\*(C`ev_default_fork\*(C'\fR or \f(CW\*(C`ev_loop_fork\*(C'\fR). The invocation is done before the |
|
|
1809 | event loop blocks next and before \f(CW\*(C`ev_check\*(C'\fR watchers are being called, |
|
|
1810 | and only in the child after the fork. If whoever good citizen calling |
|
|
1811 | \&\f(CW\*(C`ev_default_fork\*(C'\fR cheats and calls it in the wrong process, the fork |
|
|
1812 | handlers will be invoked, too, of course. |
|
|
1813 | .IP "ev_fork_init (ev_signal *, callback)" 4 |
|
|
1814 | .IX Item "ev_fork_init (ev_signal *, callback)" |
|
|
1815 | Initialises and configures the fork watcher \- it has no parameters of any |
|
|
1816 | kind. There is a \f(CW\*(C`ev_fork_set\*(C'\fR macro, but using it is utterly pointless, |
|
|
1817 | believe me. |
1366 | .SH "OTHER FUNCTIONS" |
1818 | .SH "OTHER FUNCTIONS" |
1367 | .IX Header "OTHER FUNCTIONS" |
1819 | .IX Header "OTHER FUNCTIONS" |
1368 | There are some other functions of possible interest. Described. Here. Now. |
1820 | There are some other functions of possible interest. Described. Here. Now. |
1369 | .IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4 |
1821 | .IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4 |
1370 | .IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" |
1822 | .IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" |
… | |
… | |
1432 | .IP "* The libev emulation is \fInot\fR \s-1ABI\s0 compatible to libevent, you need to use the libev header file and library." 4 |
1884 | .IP "* The libev emulation is \fInot\fR \s-1ABI\s0 compatible to libevent, you need to use the libev header file and library." 4 |
1433 | .IX Item "The libev emulation is not ABI compatible to libevent, you need to use the libev header file and library." |
1885 | .IX Item "The libev emulation is not ABI compatible to libevent, you need to use the libev header file and library." |
1434 | .PD |
1886 | .PD |
1435 | .SH "\*(C+ SUPPORT" |
1887 | .SH "\*(C+ SUPPORT" |
1436 | .IX Header " SUPPORT" |
1888 | .IX Header " SUPPORT" |
1437 | \&\s-1TBD\s0. |
1889 | Libev comes with some simplistic wrapper classes for \*(C+ that mainly allow |
|
|
1890 | you to use some convinience methods to start/stop watchers and also change |
|
|
1891 | the callback model to a model using method callbacks on objects. |
|
|
1892 | .PP |
|
|
1893 | To use it, |
|
|
1894 | .PP |
|
|
1895 | .Vb 1 |
|
|
1896 | \& #include <ev++.h> |
|
|
1897 | .Ve |
|
|
1898 | .PP |
|
|
1899 | (it is not installed by default). This automatically includes \fIev.h\fR |
|
|
1900 | and puts all of its definitions (many of them macros) into the global |
|
|
1901 | namespace. All \*(C+ specific things are put into the \f(CW\*(C`ev\*(C'\fR namespace. |
|
|
1902 | .PP |
|
|
1903 | It should support all the same embedding options as \fIev.h\fR, most notably |
|
|
1904 | \&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. |
|
|
1905 | .PP |
|
|
1906 | Here is a list of things available in the \f(CW\*(C`ev\*(C'\fR namespace: |
|
|
1907 | .ie n .IP """ev::READ""\fR, \f(CW""ev::WRITE"" etc." 4 |
|
|
1908 | .el .IP "\f(CWev::READ\fR, \f(CWev::WRITE\fR etc." 4 |
|
|
1909 | .IX Item "ev::READ, ev::WRITE etc." |
|
|
1910 | These are just enum values with the same values as the \f(CW\*(C`EV_READ\*(C'\fR etc. |
|
|
1911 | macros from \fIev.h\fR. |
|
|
1912 | .ie n .IP """ev::tstamp""\fR, \f(CW""ev::now""" 4 |
|
|
1913 | .el .IP "\f(CWev::tstamp\fR, \f(CWev::now\fR" 4 |
|
|
1914 | .IX Item "ev::tstamp, ev::now" |
|
|
1915 | Aliases to the same types/functions as with the \f(CW\*(C`ev_\*(C'\fR prefix. |
|
|
1916 | .ie n .IP """ev::io""\fR, \f(CW""ev::timer""\fR, \f(CW""ev::periodic""\fR, \f(CW""ev::idle""\fR, \f(CW""ev::sig"" etc." 4 |
|
|
1917 | .el .IP "\f(CWev::io\fR, \f(CWev::timer\fR, \f(CWev::periodic\fR, \f(CWev::idle\fR, \f(CWev::sig\fR etc." 4 |
|
|
1918 | .IX Item "ev::io, ev::timer, ev::periodic, ev::idle, ev::sig etc." |
|
|
1919 | For each \f(CW\*(C`ev_TYPE\*(C'\fR watcher in \fIev.h\fR there is a corresponding class of |
|
|
1920 | the same name in the \f(CW\*(C`ev\*(C'\fR namespace, with the exception of \f(CW\*(C`ev_signal\*(C'\fR |
|
|
1921 | which is called \f(CW\*(C`ev::sig\*(C'\fR to avoid clashes with the \f(CW\*(C`signal\*(C'\fR macro |
|
|
1922 | defines by many implementations. |
|
|
1923 | .Sp |
|
|
1924 | All of those classes have these methods: |
|
|
1925 | .RS 4 |
|
|
1926 | .IP "ev::TYPE::TYPE (object *, object::method *)" 4 |
|
|
1927 | .IX Item "ev::TYPE::TYPE (object *, object::method *)" |
|
|
1928 | .PD 0 |
|
|
1929 | .IP "ev::TYPE::TYPE (object *, object::method *, struct ev_loop *)" 4 |
|
|
1930 | .IX Item "ev::TYPE::TYPE (object *, object::method *, struct ev_loop *)" |
|
|
1931 | .IP "ev::TYPE::~TYPE" 4 |
|
|
1932 | .IX Item "ev::TYPE::~TYPE" |
|
|
1933 | .PD |
|
|
1934 | The constructor takes a pointer to an object and a method pointer to |
|
|
1935 | the event handler callback to call in this class. The constructor calls |
|
|
1936 | \&\f(CW\*(C`ev_init\*(C'\fR for you, which means you have to call the \f(CW\*(C`set\*(C'\fR method |
|
|
1937 | before starting it. If you do not specify a loop then the constructor |
|
|
1938 | automatically associates the default loop with this watcher. |
|
|
1939 | .Sp |
|
|
1940 | The destructor automatically stops the watcher if it is active. |
|
|
1941 | .IP "w\->set (struct ev_loop *)" 4 |
|
|
1942 | .IX Item "w->set (struct ev_loop *)" |
|
|
1943 | Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only |
|
|
1944 | do this when the watcher is inactive (and not pending either). |
|
|
1945 | .IP "w\->set ([args])" 4 |
|
|
1946 | .IX Item "w->set ([args])" |
|
|
1947 | Basically the same as \f(CW\*(C`ev_TYPE_set\*(C'\fR, with the same args. Must be |
|
|
1948 | called at least once. Unlike the C counterpart, an active watcher gets |
|
|
1949 | automatically stopped and restarted. |
|
|
1950 | .IP "w\->start ()" 4 |
|
|
1951 | .IX Item "w->start ()" |
|
|
1952 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument as the |
|
|
1953 | constructor already takes the loop. |
|
|
1954 | .IP "w\->stop ()" 4 |
|
|
1955 | .IX Item "w->stop ()" |
|
|
1956 | Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument. |
|
|
1957 | .ie n .IP "w\->again () ""ev::timer""\fR, \f(CW""ev::periodic"" only" 4 |
|
|
1958 | .el .IP "w\->again () \f(CWev::timer\fR, \f(CWev::periodic\fR only" 4 |
|
|
1959 | .IX Item "w->again () ev::timer, ev::periodic only" |
|
|
1960 | For \f(CW\*(C`ev::timer\*(C'\fR and \f(CW\*(C`ev::periodic\*(C'\fR, this invokes the corresponding |
|
|
1961 | \&\f(CW\*(C`ev_TYPE_again\*(C'\fR function. |
|
|
1962 | .ie n .IP "w\->sweep () ""ev::embed"" only" 4 |
|
|
1963 | .el .IP "w\->sweep () \f(CWev::embed\fR only" 4 |
|
|
1964 | .IX Item "w->sweep () ev::embed only" |
|
|
1965 | Invokes \f(CW\*(C`ev_embed_sweep\*(C'\fR. |
|
|
1966 | .ie n .IP "w\->update () ""ev::stat"" only" 4 |
|
|
1967 | .el .IP "w\->update () \f(CWev::stat\fR only" 4 |
|
|
1968 | .IX Item "w->update () ev::stat only" |
|
|
1969 | Invokes \f(CW\*(C`ev_stat_stat\*(C'\fR. |
|
|
1970 | .RE |
|
|
1971 | .RS 4 |
|
|
1972 | .RE |
|
|
1973 | .PP |
|
|
1974 | Example: Define a class with an \s-1IO\s0 and idle watcher, start one of them in |
|
|
1975 | the constructor. |
|
|
1976 | .PP |
|
|
1977 | .Vb 4 |
|
|
1978 | \& class myclass |
|
|
1979 | \& { |
|
|
1980 | \& ev_io io; void io_cb (ev::io &w, int revents); |
|
|
1981 | \& ev_idle idle void idle_cb (ev::idle &w, int revents); |
|
|
1982 | .Ve |
|
|
1983 | .PP |
|
|
1984 | .Vb 2 |
|
|
1985 | \& myclass (); |
|
|
1986 | \& } |
|
|
1987 | .Ve |
|
|
1988 | .PP |
|
|
1989 | .Vb 6 |
|
|
1990 | \& myclass::myclass (int fd) |
|
|
1991 | \& : io (this, &myclass::io_cb), |
|
|
1992 | \& idle (this, &myclass::idle_cb) |
|
|
1993 | \& { |
|
|
1994 | \& io.start (fd, ev::READ); |
|
|
1995 | \& } |
|
|
1996 | .Ve |
|
|
1997 | .SH "MACRO MAGIC" |
|
|
1998 | .IX Header "MACRO MAGIC" |
|
|
1999 | Libev can be compiled with a variety of options, the most fundemantal is |
|
|
2000 | \&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines whether (most) functions and |
|
|
2001 | callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument. |
|
|
2002 | .PP |
|
|
2003 | To make it easier to write programs that cope with either variant, the |
|
|
2004 | following macros are defined: |
|
|
2005 | .ie n .IP """EV_A""\fR, \f(CW""EV_A_""" 4 |
|
|
2006 | .el .IP "\f(CWEV_A\fR, \f(CWEV_A_\fR" 4 |
|
|
2007 | .IX Item "EV_A, EV_A_" |
|
|
2008 | This provides the loop \fIargument\fR for functions, if one is required (\*(L"ev |
|
|
2009 | loop argument\*(R"). The \f(CW\*(C`EV_A\*(C'\fR form is used when this is the sole argument, |
|
|
2010 | \&\f(CW\*(C`EV_A_\*(C'\fR is used when other arguments are following. Example: |
|
|
2011 | .Sp |
|
|
2012 | .Vb 3 |
|
|
2013 | \& ev_unref (EV_A); |
|
|
2014 | \& ev_timer_add (EV_A_ watcher); |
|
|
2015 | \& ev_loop (EV_A_ 0); |
|
|
2016 | .Ve |
|
|
2017 | .Sp |
|
|
2018 | It assumes the variable \f(CW\*(C`loop\*(C'\fR of type \f(CW\*(C`struct ev_loop *\*(C'\fR is in scope, |
|
|
2019 | which is often provided by the following macro. |
|
|
2020 | .ie n .IP """EV_P""\fR, \f(CW""EV_P_""" 4 |
|
|
2021 | .el .IP "\f(CWEV_P\fR, \f(CWEV_P_\fR" 4 |
|
|
2022 | .IX Item "EV_P, EV_P_" |
|
|
2023 | This provides the loop \fIparameter\fR for functions, if one is required (\*(L"ev |
|
|
2024 | loop parameter\*(R"). The \f(CW\*(C`EV_P\*(C'\fR form is used when this is the sole parameter, |
|
|
2025 | \&\f(CW\*(C`EV_P_\*(C'\fR is used when other parameters are following. Example: |
|
|
2026 | .Sp |
|
|
2027 | .Vb 2 |
|
|
2028 | \& // this is how ev_unref is being declared |
|
|
2029 | \& static void ev_unref (EV_P); |
|
|
2030 | .Ve |
|
|
2031 | .Sp |
|
|
2032 | .Vb 2 |
|
|
2033 | \& // this is how you can declare your typical callback |
|
|
2034 | \& static void cb (EV_P_ ev_timer *w, int revents) |
|
|
2035 | .Ve |
|
|
2036 | .Sp |
|
|
2037 | It declares a parameter \f(CW\*(C`loop\*(C'\fR of type \f(CW\*(C`struct ev_loop *\*(C'\fR, quite |
|
|
2038 | suitable for use with \f(CW\*(C`EV_A\*(C'\fR. |
|
|
2039 | .ie n .IP """EV_DEFAULT""\fR, \f(CW""EV_DEFAULT_""" 4 |
|
|
2040 | .el .IP "\f(CWEV_DEFAULT\fR, \f(CWEV_DEFAULT_\fR" 4 |
|
|
2041 | .IX Item "EV_DEFAULT, EV_DEFAULT_" |
|
|
2042 | Similar to the other two macros, this gives you the value of the default |
|
|
2043 | loop, if multiple loops are supported (\*(L"ev loop default\*(R"). |
|
|
2044 | .PP |
|
|
2045 | Example: Declare and initialise a check watcher, utilising the above |
|
|
2046 | macros so it will work regardless of whether multiple loops are supported |
|
|
2047 | or not. |
|
|
2048 | .PP |
|
|
2049 | .Vb 5 |
|
|
2050 | \& static void |
|
|
2051 | \& check_cb (EV_P_ ev_timer *w, int revents) |
|
|
2052 | \& { |
|
|
2053 | \& ev_check_stop (EV_A_ w); |
|
|
2054 | \& } |
|
|
2055 | .Ve |
|
|
2056 | .PP |
|
|
2057 | .Vb 4 |
|
|
2058 | \& ev_check check; |
|
|
2059 | \& ev_check_init (&check, check_cb); |
|
|
2060 | \& ev_check_start (EV_DEFAULT_ &check); |
|
|
2061 | \& ev_loop (EV_DEFAULT_ 0); |
|
|
2062 | .Ve |
|
|
2063 | .SH "EMBEDDING" |
|
|
2064 | .IX Header "EMBEDDING" |
|
|
2065 | Libev can (and often is) directly embedded into host |
|
|
2066 | applications. Examples of applications that embed it include the Deliantra |
|
|
2067 | Game Server, the \s-1EV\s0 perl module, the \s-1GNU\s0 Virtual Private Ethernet (gvpe) |
|
|
2068 | and rxvt\-unicode. |
|
|
2069 | .PP |
|
|
2070 | The goal is to enable you to just copy the neecssary files into your |
|
|
2071 | source directory without having to change even a single line in them, so |
|
|
2072 | you can easily upgrade by simply copying (or having a checked-out copy of |
|
|
2073 | libev somewhere in your source tree). |
|
|
2074 | .Sh "\s-1FILESETS\s0" |
|
|
2075 | .IX Subsection "FILESETS" |
|
|
2076 | Depending on what features you need you need to include one or more sets of files |
|
|
2077 | in your app. |
|
|
2078 | .PP |
|
|
2079 | \fI\s-1CORE\s0 \s-1EVENT\s0 \s-1LOOP\s0\fR |
|
|
2080 | .IX Subsection "CORE EVENT LOOP" |
|
|
2081 | .PP |
|
|
2082 | To include only the libev core (all the \f(CW\*(C`ev_*\*(C'\fR functions), with manual |
|
|
2083 | configuration (no autoconf): |
|
|
2084 | .PP |
|
|
2085 | .Vb 2 |
|
|
2086 | \& #define EV_STANDALONE 1 |
|
|
2087 | \& #include "ev.c" |
|
|
2088 | .Ve |
|
|
2089 | .PP |
|
|
2090 | This will automatically include \fIev.h\fR, too, and should be done in a |
|
|
2091 | single C source file only to provide the function implementations. To use |
|
|
2092 | it, do the same for \fIev.h\fR in all files wishing to use this \s-1API\s0 (best |
|
|
2093 | done by writing a wrapper around \fIev.h\fR that you can include instead and |
|
|
2094 | where you can put other configuration options): |
|
|
2095 | .PP |
|
|
2096 | .Vb 2 |
|
|
2097 | \& #define EV_STANDALONE 1 |
|
|
2098 | \& #include "ev.h" |
|
|
2099 | .Ve |
|
|
2100 | .PP |
|
|
2101 | Both header files and implementation files can be compiled with a \*(C+ |
|
|
2102 | compiler (at least, thats a stated goal, and breakage will be treated |
|
|
2103 | as a bug). |
|
|
2104 | .PP |
|
|
2105 | You need the following files in your source tree, or in a directory |
|
|
2106 | in your include path (e.g. in libev/ when using \-Ilibev): |
|
|
2107 | .PP |
|
|
2108 | .Vb 4 |
|
|
2109 | \& ev.h |
|
|
2110 | \& ev.c |
|
|
2111 | \& ev_vars.h |
|
|
2112 | \& ev_wrap.h |
|
|
2113 | .Ve |
|
|
2114 | .PP |
|
|
2115 | .Vb 1 |
|
|
2116 | \& ev_win32.c required on win32 platforms only |
|
|
2117 | .Ve |
|
|
2118 | .PP |
|
|
2119 | .Vb 5 |
|
|
2120 | \& ev_select.c only when select backend is enabled (which is enabled by default) |
|
|
2121 | \& ev_poll.c only when poll backend is enabled (disabled by default) |
|
|
2122 | \& ev_epoll.c only when the epoll backend is enabled (disabled by default) |
|
|
2123 | \& ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
|
|
2124 | \& ev_port.c only when the solaris port backend is enabled (disabled by default) |
|
|
2125 | .Ve |
|
|
2126 | .PP |
|
|
2127 | \&\fIev.c\fR includes the backend files directly when enabled, so you only need |
|
|
2128 | to compile this single file. |
|
|
2129 | .PP |
|
|
2130 | \fI\s-1LIBEVENT\s0 \s-1COMPATIBILITY\s0 \s-1API\s0\fR |
|
|
2131 | .IX Subsection "LIBEVENT COMPATIBILITY API" |
|
|
2132 | .PP |
|
|
2133 | To include the libevent compatibility \s-1API\s0, also include: |
|
|
2134 | .PP |
|
|
2135 | .Vb 1 |
|
|
2136 | \& #include "event.c" |
|
|
2137 | .Ve |
|
|
2138 | .PP |
|
|
2139 | in the file including \fIev.c\fR, and: |
|
|
2140 | .PP |
|
|
2141 | .Vb 1 |
|
|
2142 | \& #include "event.h" |
|
|
2143 | .Ve |
|
|
2144 | .PP |
|
|
2145 | in the files that want to use the libevent \s-1API\s0. This also includes \fIev.h\fR. |
|
|
2146 | .PP |
|
|
2147 | You need the following additional files for this: |
|
|
2148 | .PP |
|
|
2149 | .Vb 2 |
|
|
2150 | \& event.h |
|
|
2151 | \& event.c |
|
|
2152 | .Ve |
|
|
2153 | .PP |
|
|
2154 | \fI\s-1AUTOCONF\s0 \s-1SUPPORT\s0\fR |
|
|
2155 | .IX Subsection "AUTOCONF SUPPORT" |
|
|
2156 | .PP |
|
|
2157 | Instead of using \f(CW\*(C`EV_STANDALONE=1\*(C'\fR and providing your config in |
|
|
2158 | whatever way you want, you can also \f(CW\*(C`m4_include([libev.m4])\*(C'\fR in your |
|
|
2159 | \&\fIconfigure.ac\fR and leave \f(CW\*(C`EV_STANDALONE\*(C'\fR undefined. \fIev.c\fR will then |
|
|
2160 | include \fIconfig.h\fR and configure itself accordingly. |
|
|
2161 | .PP |
|
|
2162 | For this of course you need the m4 file: |
|
|
2163 | .PP |
|
|
2164 | .Vb 1 |
|
|
2165 | \& libev.m4 |
|
|
2166 | .Ve |
|
|
2167 | .Sh "\s-1PREPROCESSOR\s0 \s-1SYMBOLS/MACROS\s0" |
|
|
2168 | .IX Subsection "PREPROCESSOR SYMBOLS/MACROS" |
|
|
2169 | Libev can be configured via a variety of preprocessor symbols you have to define |
|
|
2170 | before including any of its files. The default is not to build for multiplicity |
|
|
2171 | and only include the select backend. |
|
|
2172 | .IP "\s-1EV_STANDALONE\s0" 4 |
|
|
2173 | .IX Item "EV_STANDALONE" |
|
|
2174 | Must always be \f(CW1\fR if you do not use autoconf configuration, which |
|
|
2175 | keeps libev from including \fIconfig.h\fR, and it also defines dummy |
|
|
2176 | implementations for some libevent functions (such as logging, which is not |
|
|
2177 | supported). It will also not define any of the structs usually found in |
|
|
2178 | \&\fIevent.h\fR that are not directly supported by the libev core alone. |
|
|
2179 | .IP "\s-1EV_USE_MONOTONIC\s0" 4 |
|
|
2180 | .IX Item "EV_USE_MONOTONIC" |
|
|
2181 | If defined to be \f(CW1\fR, libev will try to detect the availability of the |
|
|
2182 | monotonic clock option at both compiletime and runtime. Otherwise no use |
|
|
2183 | of the monotonic clock option will be attempted. If you enable this, you |
|
|
2184 | usually have to link against librt or something similar. Enabling it when |
|
|
2185 | the functionality isn't available is safe, though, althoguh you have |
|
|
2186 | to make sure you link against any libraries where the \f(CW\*(C`clock_gettime\*(C'\fR |
|
|
2187 | function is hiding in (often \fI\-lrt\fR). |
|
|
2188 | .IP "\s-1EV_USE_REALTIME\s0" 4 |
|
|
2189 | .IX Item "EV_USE_REALTIME" |
|
|
2190 | If defined to be \f(CW1\fR, libev will try to detect the availability of the |
|
|
2191 | realtime clock option at compiletime (and assume its availability at |
|
|
2192 | runtime if successful). Otherwise no use of the realtime clock option will |
|
|
2193 | be attempted. This effectively replaces \f(CW\*(C`gettimeofday\*(C'\fR by \f(CW\*(C`clock_get |
|
|
2194 | (CLOCK_REALTIME, ...)\*(C'\fR and will not normally affect correctness. See tzhe note about libraries |
|
|
2195 | in the description of \f(CW\*(C`EV_USE_MONOTONIC\*(C'\fR, though. |
|
|
2196 | .IP "\s-1EV_USE_SELECT\s0" 4 |
|
|
2197 | .IX Item "EV_USE_SELECT" |
|
|
2198 | If undefined or defined to be \f(CW1\fR, libev will compile in support for the |
|
|
2199 | \&\f(CW\*(C`select\*(C'\fR(2) backend. No attempt at autodetection will be done: if no |
|
|
2200 | other method takes over, select will be it. Otherwise the select backend |
|
|
2201 | will not be compiled in. |
|
|
2202 | .IP "\s-1EV_SELECT_USE_FD_SET\s0" 4 |
|
|
2203 | .IX Item "EV_SELECT_USE_FD_SET" |
|
|
2204 | If defined to \f(CW1\fR, then the select backend will use the system \f(CW\*(C`fd_set\*(C'\fR |
|
|
2205 | structure. This is useful if libev doesn't compile due to a missing |
|
|
2206 | \&\f(CW\*(C`NFDBITS\*(C'\fR or \f(CW\*(C`fd_mask\*(C'\fR definition or it misguesses the bitset layout on |
|
|
2207 | exotic systems. This usually limits the range of file descriptors to some |
|
|
2208 | low limit such as 1024 or might have other limitations (winsocket only |
|
|
2209 | allows 64 sockets). The \f(CW\*(C`FD_SETSIZE\*(C'\fR macro, set before compilation, might |
|
|
2210 | influence the size of the \f(CW\*(C`fd_set\*(C'\fR used. |
|
|
2211 | .IP "\s-1EV_SELECT_IS_WINSOCKET\s0" 4 |
|
|
2212 | .IX Item "EV_SELECT_IS_WINSOCKET" |
|
|
2213 | When defined to \f(CW1\fR, the select backend will assume that |
|
|
2214 | select/socket/connect etc. don't understand file descriptors but |
|
|
2215 | wants osf handles on win32 (this is the case when the select to |
|
|
2216 | be used is the winsock select). This means that it will call |
|
|
2217 | \&\f(CW\*(C`_get_osfhandle\*(C'\fR on the fd to convert it to an \s-1OS\s0 handle. Otherwise, |
|
|
2218 | it is assumed that all these functions actually work on fds, even |
|
|
2219 | on win32. Should not be defined on non\-win32 platforms. |
|
|
2220 | .IP "\s-1EV_USE_POLL\s0" 4 |
|
|
2221 | .IX Item "EV_USE_POLL" |
|
|
2222 | If defined to be \f(CW1\fR, libev will compile in support for the \f(CW\*(C`poll\*(C'\fR(2) |
|
|
2223 | backend. Otherwise it will be enabled on non\-win32 platforms. It |
|
|
2224 | takes precedence over select. |
|
|
2225 | .IP "\s-1EV_USE_EPOLL\s0" 4 |
|
|
2226 | .IX Item "EV_USE_EPOLL" |
|
|
2227 | If defined to be \f(CW1\fR, libev will compile in support for the Linux |
|
|
2228 | \&\f(CW\*(C`epoll\*(C'\fR(7) backend. Its availability will be detected at runtime, |
|
|
2229 | otherwise another method will be used as fallback. This is the |
|
|
2230 | preferred backend for GNU/Linux systems. |
|
|
2231 | .IP "\s-1EV_USE_KQUEUE\s0" 4 |
|
|
2232 | .IX Item "EV_USE_KQUEUE" |
|
|
2233 | If defined to be \f(CW1\fR, libev will compile in support for the \s-1BSD\s0 style |
|
|
2234 | \&\f(CW\*(C`kqueue\*(C'\fR(2) backend. Its actual availability will be detected at runtime, |
|
|
2235 | otherwise another method will be used as fallback. This is the preferred |
|
|
2236 | backend for \s-1BSD\s0 and BSD-like systems, although on most BSDs kqueue only |
|
|
2237 | supports some types of fds correctly (the only platform we found that |
|
|
2238 | supports ptys for example was NetBSD), so kqueue might be compiled in, but |
|
|
2239 | not be used unless explicitly requested. The best way to use it is to find |
|
|
2240 | out whether kqueue supports your type of fd properly and use an embedded |
|
|
2241 | kqueue loop. |
|
|
2242 | .IP "\s-1EV_USE_PORT\s0" 4 |
|
|
2243 | .IX Item "EV_USE_PORT" |
|
|
2244 | If defined to be \f(CW1\fR, libev will compile in support for the Solaris |
|
|
2245 | 10 port style backend. Its availability will be detected at runtime, |
|
|
2246 | otherwise another method will be used as fallback. This is the preferred |
|
|
2247 | backend for Solaris 10 systems. |
|
|
2248 | .IP "\s-1EV_USE_DEVPOLL\s0" 4 |
|
|
2249 | .IX Item "EV_USE_DEVPOLL" |
|
|
2250 | reserved for future expansion, works like the \s-1USE\s0 symbols above. |
|
|
2251 | .IP "\s-1EV_USE_INOTIFY\s0" 4 |
|
|
2252 | .IX Item "EV_USE_INOTIFY" |
|
|
2253 | If defined to be \f(CW1\fR, libev will compile in support for the Linux inotify |
|
|
2254 | interface to speed up \f(CW\*(C`ev_stat\*(C'\fR watchers. Its actual availability will |
|
|
2255 | be detected at runtime. |
|
|
2256 | .IP "\s-1EV_H\s0" 4 |
|
|
2257 | .IX Item "EV_H" |
|
|
2258 | The name of the \fIev.h\fR header file used to include it. The default if |
|
|
2259 | undefined is \f(CW\*(C`<ev.h>\*(C'\fR in \fIevent.h\fR and \f(CW"ev.h"\fR in \fIev.c\fR. This |
|
|
2260 | can be used to virtually rename the \fIev.h\fR header file in case of conflicts. |
|
|
2261 | .IP "\s-1EV_CONFIG_H\s0" 4 |
|
|
2262 | .IX Item "EV_CONFIG_H" |
|
|
2263 | If \f(CW\*(C`EV_STANDALONE\*(C'\fR isn't \f(CW1\fR, this variable can be used to override |
|
|
2264 | \&\fIev.c\fR's idea of where to find the \fIconfig.h\fR file, similarly to |
|
|
2265 | \&\f(CW\*(C`EV_H\*(C'\fR, above. |
|
|
2266 | .IP "\s-1EV_EVENT_H\s0" 4 |
|
|
2267 | .IX Item "EV_EVENT_H" |
|
|
2268 | Similarly to \f(CW\*(C`EV_H\*(C'\fR, this macro can be used to override \fIevent.c\fR's idea |
|
|
2269 | of how the \fIevent.h\fR header can be found. |
|
|
2270 | .IP "\s-1EV_PROTOTYPES\s0" 4 |
|
|
2271 | .IX Item "EV_PROTOTYPES" |
|
|
2272 | If defined to be \f(CW0\fR, then \fIev.h\fR will not define any function |
|
|
2273 | prototypes, but still define all the structs and other symbols. This is |
|
|
2274 | occasionally useful if you want to provide your own wrapper functions |
|
|
2275 | around libev functions. |
|
|
2276 | .IP "\s-1EV_MULTIPLICITY\s0" 4 |
|
|
2277 | .IX Item "EV_MULTIPLICITY" |
|
|
2278 | If undefined or defined to \f(CW1\fR, then all event-loop-specific functions |
|
|
2279 | will have the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument, and you can create |
|
|
2280 | additional independent event loops. Otherwise there will be no support |
|
|
2281 | for multiple event loops and there is no first event loop pointer |
|
|
2282 | argument. Instead, all functions act on the single default loop. |
|
|
2283 | .IP "\s-1EV_MINPRI\s0" 4 |
|
|
2284 | .IX Item "EV_MINPRI" |
|
|
2285 | .PD 0 |
|
|
2286 | .IP "\s-1EV_MAXPRI\s0" 4 |
|
|
2287 | .IX Item "EV_MAXPRI" |
|
|
2288 | .PD |
|
|
2289 | The range of allowed priorities. \f(CW\*(C`EV_MINPRI\*(C'\fR must be smaller or equal to |
|
|
2290 | \&\f(CW\*(C`EV_MAXPRI\*(C'\fR, but otherwise there are no non-obvious limitations. You can |
|
|
2291 | provide for more priorities by overriding those symbols (usually defined |
|
|
2292 | to be \f(CW\*(C`\-2\*(C'\fR and \f(CW2\fR, respectively). |
|
|
2293 | .Sp |
|
|
2294 | When doing priority-based operations, libev usually has to linearly search |
|
|
2295 | all the priorities, so having many of them (hundreds) uses a lot of space |
|
|
2296 | and time, so using the defaults of five priorities (\-2 .. +2) is usually |
|
|
2297 | fine. |
|
|
2298 | .Sp |
|
|
2299 | If your embedding app does not need any priorities, defining these both to |
|
|
2300 | \&\f(CW0\fR will save some memory and cpu. |
|
|
2301 | .IP "\s-1EV_PERIODIC_ENABLE\s0" 4 |
|
|
2302 | .IX Item "EV_PERIODIC_ENABLE" |
|
|
2303 | If undefined or defined to be \f(CW1\fR, then periodic timers are supported. If |
|
|
2304 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
|
|
2305 | code. |
|
|
2306 | .IP "\s-1EV_IDLE_ENABLE\s0" 4 |
|
|
2307 | .IX Item "EV_IDLE_ENABLE" |
|
|
2308 | If undefined or defined to be \f(CW1\fR, then idle watchers are supported. If |
|
|
2309 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
|
|
2310 | code. |
|
|
2311 | .IP "\s-1EV_EMBED_ENABLE\s0" 4 |
|
|
2312 | .IX Item "EV_EMBED_ENABLE" |
|
|
2313 | If undefined or defined to be \f(CW1\fR, then embed watchers are supported. If |
|
|
2314 | defined to be \f(CW0\fR, then they are not. |
|
|
2315 | .IP "\s-1EV_STAT_ENABLE\s0" 4 |
|
|
2316 | .IX Item "EV_STAT_ENABLE" |
|
|
2317 | If undefined or defined to be \f(CW1\fR, then stat watchers are supported. If |
|
|
2318 | defined to be \f(CW0\fR, then they are not. |
|
|
2319 | .IP "\s-1EV_FORK_ENABLE\s0" 4 |
|
|
2320 | .IX Item "EV_FORK_ENABLE" |
|
|
2321 | If undefined or defined to be \f(CW1\fR, then fork watchers are supported. If |
|
|
2322 | defined to be \f(CW0\fR, then they are not. |
|
|
2323 | .IP "\s-1EV_MINIMAL\s0" 4 |
|
|
2324 | .IX Item "EV_MINIMAL" |
|
|
2325 | If you need to shave off some kilobytes of code at the expense of some |
|
|
2326 | speed, define this symbol to \f(CW1\fR. Currently only used for gcc to override |
|
|
2327 | some inlining decisions, saves roughly 30% codesize of amd64. |
|
|
2328 | .IP "\s-1EV_PID_HASHSIZE\s0" 4 |
|
|
2329 | .IX Item "EV_PID_HASHSIZE" |
|
|
2330 | \&\f(CW\*(C`ev_child\*(C'\fR watchers use a small hash table to distribute workload by |
|
|
2331 | pid. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), usually more |
|
|
2332 | than enough. If you need to manage thousands of children you might want to |
|
|
2333 | increase this value (\fImust\fR be a power of two). |
|
|
2334 | .IP "\s-1EV_INOTIFY_HASHSIZE\s0" 4 |
|
|
2335 | .IX Item "EV_INOTIFY_HASHSIZE" |
|
|
2336 | \&\f(CW\*(C`ev_staz\*(C'\fR watchers use a small hash table to distribute workload by |
|
|
2337 | inotify watch id. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), |
|
|
2338 | usually more than enough. If you need to manage thousands of \f(CW\*(C`ev_stat\*(C'\fR |
|
|
2339 | watchers you might want to increase this value (\fImust\fR be a power of |
|
|
2340 | two). |
|
|
2341 | .IP "\s-1EV_COMMON\s0" 4 |
|
|
2342 | .IX Item "EV_COMMON" |
|
|
2343 | By default, all watchers have a \f(CW\*(C`void *data\*(C'\fR member. By redefining |
|
|
2344 | this macro to a something else you can include more and other types of |
|
|
2345 | members. You have to define it each time you include one of the files, |
|
|
2346 | though, and it must be identical each time. |
|
|
2347 | .Sp |
|
|
2348 | For example, the perl \s-1EV\s0 module uses something like this: |
|
|
2349 | .Sp |
|
|
2350 | .Vb 3 |
|
|
2351 | \& #define EV_COMMON \e |
|
|
2352 | \& SV *self; /* contains this struct */ \e |
|
|
2353 | \& SV *cb_sv, *fh /* note no trailing ";" */ |
|
|
2354 | .Ve |
|
|
2355 | .IP "\s-1EV_CB_DECLARE\s0 (type)" 4 |
|
|
2356 | .IX Item "EV_CB_DECLARE (type)" |
|
|
2357 | .PD 0 |
|
|
2358 | .IP "\s-1EV_CB_INVOKE\s0 (watcher, revents)" 4 |
|
|
2359 | .IX Item "EV_CB_INVOKE (watcher, revents)" |
|
|
2360 | .IP "ev_set_cb (ev, cb)" 4 |
|
|
2361 | .IX Item "ev_set_cb (ev, cb)" |
|
|
2362 | .PD |
|
|
2363 | Can be used to change the callback member declaration in each watcher, |
|
|
2364 | and the way callbacks are invoked and set. Must expand to a struct member |
|
|
2365 | definition and a statement, respectively. See the \fIev.v\fR header file for |
|
|
2366 | their default definitions. One possible use for overriding these is to |
|
|
2367 | avoid the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument in all cases, or to use |
|
|
2368 | method calls instead of plain function calls in \*(C+. |
|
|
2369 | .Sh "\s-1EXAMPLES\s0" |
|
|
2370 | .IX Subsection "EXAMPLES" |
|
|
2371 | For a real-world example of a program the includes libev |
|
|
2372 | verbatim, you can have a look at the \s-1EV\s0 perl module |
|
|
2373 | (<http://software.schmorp.de/pkg/EV.html>). It has the libev files in |
|
|
2374 | the \fIlibev/\fR subdirectory and includes them in the \fI\s-1EV/EVAPI\s0.h\fR (public |
|
|
2375 | interface) and \fI\s-1EV\s0.xs\fR (implementation) files. Only the \fI\s-1EV\s0.xs\fR file |
|
|
2376 | will be compiled. It is pretty complex because it provides its own header |
|
|
2377 | file. |
|
|
2378 | .Sp |
|
|
2379 | The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file |
|
|
2380 | that everybody includes and which overrides some configure choices: |
|
|
2381 | .Sp |
|
|
2382 | .Vb 9 |
|
|
2383 | \& #define EV_MINIMAL 1 |
|
|
2384 | \& #define EV_USE_POLL 0 |
|
|
2385 | \& #define EV_MULTIPLICITY 0 |
|
|
2386 | \& #define EV_PERIODIC_ENABLE 0 |
|
|
2387 | \& #define EV_STAT_ENABLE 0 |
|
|
2388 | \& #define EV_FORK_ENABLE 0 |
|
|
2389 | \& #define EV_CONFIG_H <config.h> |
|
|
2390 | \& #define EV_MINPRI 0 |
|
|
2391 | \& #define EV_MAXPRI 0 |
|
|
2392 | .Ve |
|
|
2393 | .Sp |
|
|
2394 | .Vb 1 |
|
|
2395 | \& #include "ev++.h" |
|
|
2396 | .Ve |
|
|
2397 | .Sp |
|
|
2398 | And a \fIev_cpp.C\fR implementation file that contains libev proper and is compiled: |
|
|
2399 | .Sp |
|
|
2400 | .Vb 2 |
|
|
2401 | \& #include "ev_cpp.h" |
|
|
2402 | \& #include "ev.c" |
|
|
2403 | .Ve |
|
|
2404 | .SH "COMPLEXITIES" |
|
|
2405 | .IX Header "COMPLEXITIES" |
|
|
2406 | In this section the complexities of (many of) the algorithms used inside |
|
|
2407 | libev will be explained. For complexity discussions about backends see the |
|
|
2408 | documentation for \f(CW\*(C`ev_default_init\*(C'\fR. |
|
|
2409 | .RS 4 |
|
|
2410 | .IP "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" 4 |
|
|
2411 | .IX Item "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" |
|
|
2412 | This means that, when you have a watcher that triggers in one hour and |
|
|
2413 | there are 100 watchers that would trigger before that then inserting will |
|
|
2414 | have to skip those 100 watchers. |
|
|
2415 | .IP "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" 4 |
|
|
2416 | .IX Item "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" |
|
|
2417 | That means that for changing a timer costs less than removing/adding them |
|
|
2418 | as only the relative motion in the event queue has to be paid for. |
|
|
2419 | .IP "Starting io/check/prepare/idle/signal/child watchers: O(1)" 4 |
|
|
2420 | .IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)" |
|
|
2421 | These just add the watcher into an array or at the head of a list. If |
|
|
2422 | the array needs to be extended libev needs to realloc and move the whole |
|
|
2423 | array, but this happen asymptotically less and less with more watchers, |
|
|
2424 | thus amortised O(1). |
|
|
2425 | .IP "Stopping check/prepare/idle watchers: O(1)" 4 |
|
|
2426 | .IX Item "Stopping check/prepare/idle watchers: O(1)" |
|
|
2427 | .PD 0 |
|
|
2428 | .IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % \s-1EV_PID_HASHSIZE\s0))" 4 |
|
|
2429 | .IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))" |
|
|
2430 | .PD |
|
|
2431 | These watchers are stored in lists then need to be walked to find the |
|
|
2432 | correct watcher to remove. The lists are usually short (you don't usually |
|
|
2433 | have many watchers waiting for the same fd or signal). |
|
|
2434 | .IP "Finding the next timer per loop iteration: O(1)" 4 |
|
|
2435 | .IX Item "Finding the next timer per loop iteration: O(1)" |
|
|
2436 | .PD 0 |
|
|
2437 | .IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4 |
|
|
2438 | .IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" |
|
|
2439 | .PD |
|
|
2440 | A change means an I/O watcher gets started or stopped, which requires |
|
|
2441 | libev to recalculate its status (and possibly tell the kernel). |
|
|
2442 | .IP "Activating one watcher: O(1)" 4 |
|
|
2443 | .IX Item "Activating one watcher: O(1)" |
|
|
2444 | .PD 0 |
|
|
2445 | .IP "Priority handling: O(number_of_priorities)" 4 |
|
|
2446 | .IX Item "Priority handling: O(number_of_priorities)" |
|
|
2447 | .PD |
|
|
2448 | Priorities are implemented by allocating some space for each |
|
|
2449 | priority. When doing priority-based operations, libev usually has to |
|
|
2450 | linearly search all the priorities. |
|
|
2451 | .RE |
|
|
2452 | .RS 4 |
1438 | .SH "AUTHOR" |
2453 | .SH "AUTHOR" |
1439 | .IX Header "AUTHOR" |
2454 | .IX Header "AUTHOR" |
1440 | Marc Lehmann <libev@schmorp.de>. |
2455 | Marc Lehmann <libev@schmorp.de>. |