… | |
… | |
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 "2007-11-23" "perl v5.8.8" "User Contributed Perl Documentation" |
132 | .TH "<STANDARD INPUT>" 1 "2007-11-27" "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" |
142 | Libev is an event loop: you register interest in certain events (such as a |
201 | 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 |
202 | file descriptor being readable or a timeout occuring), and it will manage |
144 | these event sources and provide your program with events. |
203 | these event sources and provide your program with events. |
… | |
… | |
151 | watchers\fR, which are relatively small C structures you initialise with the |
210 | 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 |
211 | details of the event, and then hand it over to libev by \fIstarting\fR the |
153 | watcher. |
212 | watcher. |
154 | .SH "FEATURES" |
213 | .SH "FEATURES" |
155 | .IX Header "FEATURES" |
214 | .IX Header "FEATURES" |
156 | Libev supports select, poll, the linux-specific epoll and the bsd-specific |
215 | 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 |
216 | 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 |
217 | for file descriptor events (\f(CW\*(C`ev_io\*(C'\fR), relative timers (\f(CW\*(C`ev_timer\*(C'\fR), |
159 | events (related to \s-1SIGCHLD\s0), and event watchers dealing with the event |
218 | absolute timers with customised rescheduling (\f(CW\*(C`ev_periodic\*(C'\fR), synchronous |
160 | loop mechanism itself (idle, prepare and check watchers). It also is quite |
219 | signals (\f(CW\*(C`ev_signal\*(C'\fR), process status change events (\f(CW\*(C`ev_child\*(C'\fR), and |
161 | fast (see this benchmark comparing |
220 | event watchers dealing with the event loop mechanism itself (\f(CW\*(C`ev_idle\*(C'\fR, |
162 | it to libevent for example). |
221 | \&\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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222 | file watchers (\f(CW\*(C`ev_stat\*(C'\fR) and even limited support for fork events |
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223 | (\f(CW\*(C`ev_fork\*(C'\fR). |
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224 | .PP |
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225 | It also is quite fast (see this |
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226 | benchmark comparing it to libevent |
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227 | for example). |
163 | .SH "CONVENTIONS" |
228 | .SH "CONVENTIONS" |
164 | .IX Header "CONVENTIONS" |
229 | .IX Header "CONVENTIONS" |
165 | Libev is very configurable. In this manual the default configuration |
230 | Libev is very configurable. In this manual the default configuration will |
166 | will be described, which supports multiple event loops. For more info |
231 | be described, which supports multiple event loops. For more info about |
167 | about various configuration options please have a look at the file |
232 | 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 |
233 | this manual. If libev was configured without support for multiple event |
169 | support for multiple event loops, then all functions taking an initial |
234 | 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) |
235 | (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" |
236 | .SH "TIME REPRESENTATION" |
173 | .IX Header "TIME REPRESENTATION" |
237 | .IX Header "TIME REPRESENTATION" |
174 | Libev represents time as a single floating point number, representing the |
238 | Libev represents time as a single floating point number, representing the |
175 | (fractional) number of seconds since the (\s-1POSIX\s0) epoch (somewhere near |
239 | (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 |
240 | the beginning of 1970, details are complicated, don't ask). This type is |
177 | called \f(CW\*(C`ev_tstamp\*(C'\fR, which is what you should use too. It usually aliases |
241 | called \f(CW\*(C`ev_tstamp\*(C'\fR, which is what you should use too. It usually aliases |
178 | to the double type in C. |
242 | to the \f(CW\*(C`double\*(C'\fR type in C, and when you need to do any calculations on |
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243 | it, you should treat it as such. |
179 | .SH "GLOBAL FUNCTIONS" |
244 | .SH "GLOBAL FUNCTIONS" |
180 | .IX Header "GLOBAL FUNCTIONS" |
245 | .IX Header "GLOBAL FUNCTIONS" |
181 | These functions can be called anytime, even before initialising the |
246 | These functions can be called anytime, even before initialising the |
182 | library in any way. |
247 | library in any way. |
183 | .IP "ev_tstamp ev_time ()" 4 |
248 | .IP "ev_tstamp ev_time ()" 4 |
… | |
… | |
199 | .Sp |
264 | .Sp |
200 | Usually, it's a good idea to terminate if the major versions mismatch, |
265 | Usually, it's a good idea to terminate if the major versions mismatch, |
201 | as this indicates an incompatible change. Minor versions are usually |
266 | as this indicates an incompatible change. Minor versions are usually |
202 | compatible to older versions, so a larger minor version alone is usually |
267 | compatible to older versions, so a larger minor version alone is usually |
203 | not a problem. |
268 | not a problem. |
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269 | .Sp |
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270 | Example: Make sure we haven't accidentally been linked against the wrong |
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271 | version. |
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272 | .Sp |
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273 | .Vb 3 |
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274 | \& assert (("libev version mismatch", |
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275 | \& ev_version_major () == EV_VERSION_MAJOR |
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276 | \& && ev_version_minor () >= EV_VERSION_MINOR)); |
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277 | .Ve |
204 | .IP "unsigned int ev_supported_backends ()" 4 |
278 | .IP "unsigned int ev_supported_backends ()" 4 |
205 | .IX Item "unsigned int ev_supported_backends ()" |
279 | .IX Item "unsigned int ev_supported_backends ()" |
206 | Return the set of all backends (i.e. their corresponding \f(CW\*(C`EV_BACKEND_*\*(C'\fR |
280 | Return the set of all backends (i.e. their corresponding \f(CW\*(C`EV_BACKEND_*\*(C'\fR |
207 | value) compiled into this binary of libev (independent of their |
281 | value) compiled into this binary of libev (independent of their |
208 | availability on the system you are running on). See \f(CW\*(C`ev_default_loop\*(C'\fR for |
282 | availability on the system you are running on). See \f(CW\*(C`ev_default_loop\*(C'\fR for |
209 | a description of the set values. |
283 | a description of the set values. |
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284 | .Sp |
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285 | Example: make sure we have the epoll method, because yeah this is cool and |
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286 | a must have and can we have a torrent of it please!!!11 |
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287 | .Sp |
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288 | .Vb 2 |
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289 | \& assert (("sorry, no epoll, no sex", |
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290 | \& ev_supported_backends () & EVBACKEND_EPOLL)); |
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291 | .Ve |
210 | .IP "unsigned int ev_recommended_backends ()" 4 |
292 | .IP "unsigned int ev_recommended_backends ()" 4 |
211 | .IX Item "unsigned int ev_recommended_backends ()" |
293 | .IX Item "unsigned int ev_recommended_backends ()" |
212 | Return the set of all backends compiled into this binary of libev and also |
294 | Return the set of all backends compiled into this binary of libev and also |
213 | recommended for this platform. This set is often smaller than the one |
295 | recommended for this platform. This set is often smaller than the one |
214 | returned by \f(CW\*(C`ev_supported_backends\*(C'\fR, as for example kqueue is broken on |
296 | returned by \f(CW\*(C`ev_supported_backends\*(C'\fR, as for example kqueue is broken on |
215 | most BSDs and will not be autodetected unless you explicitly request it |
297 | most BSDs and will not be autodetected unless you explicitly request it |
216 | (assuming you know what you are doing). This is the set of backends that |
298 | (assuming you know what you are doing). This is the set of backends that |
217 | \&\f(CW\*(C`EVFLAG_AUTO\*(C'\fR will probe for. |
299 | libev will probe for if you specify no backends explicitly. |
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300 | .IP "unsigned int ev_embeddable_backends ()" 4 |
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301 | .IX Item "unsigned int ev_embeddable_backends ()" |
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302 | Returns the set of backends that are embeddable in other event loops. This |
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303 | is the theoretical, all\-platform, value. To find which backends |
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304 | might be supported on the current system, you would need to look at |
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305 | \&\f(CW\*(C`ev_embeddable_backends () & ev_supported_backends ()\*(C'\fR, likewise for |
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306 | recommended ones. |
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307 | .Sp |
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308 | See the description of \f(CW\*(C`ev_embed\*(C'\fR watchers for more info. |
218 | .IP "ev_set_allocator (void *(*cb)(void *ptr, long size))" 4 |
309 | .IP "ev_set_allocator (void *(*cb)(void *ptr, size_t size))" 4 |
219 | .IX Item "ev_set_allocator (void *(*cb)(void *ptr, long size))" |
310 | .IX Item "ev_set_allocator (void *(*cb)(void *ptr, size_t size))" |
220 | Sets the allocation function to use (the prototype is similar to the |
311 | Sets the allocation function to use (the prototype and semantics are |
221 | realloc C function, the semantics are identical). It is used to allocate |
312 | identical to the realloc C function). It is used to allocate and free |
222 | and free memory (no surprises here). If it returns zero when memory |
313 | memory (no surprises here). If it returns zero when memory needs to be |
223 | needs to be allocated, the library might abort or take some potentially |
314 | allocated, the library might abort or take some potentially destructive |
224 | destructive action. The default is your system realloc function. |
315 | action. The default is your system realloc function. |
225 | .Sp |
316 | .Sp |
226 | You could override this function in high-availability programs to, say, |
317 | You could override this function in high-availability programs to, say, |
227 | free some memory if it cannot allocate memory, to use a special allocator, |
318 | free some memory if it cannot allocate memory, to use a special allocator, |
228 | or even to sleep a while and retry until some memory is available. |
319 | or even to sleep a while and retry until some memory is available. |
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320 | .Sp |
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321 | Example: Replace the libev allocator with one that waits a bit and then |
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322 | retries). |
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323 | .Sp |
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324 | .Vb 6 |
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325 | \& static void * |
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326 | \& persistent_realloc (void *ptr, size_t size) |
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327 | \& { |
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328 | \& for (;;) |
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329 | \& { |
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330 | \& void *newptr = realloc (ptr, size); |
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331 | .Ve |
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332 | .Sp |
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333 | .Vb 2 |
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334 | \& if (newptr) |
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335 | \& return newptr; |
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336 | .Ve |
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337 | .Sp |
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338 | .Vb 3 |
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339 | \& sleep (60); |
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340 | \& } |
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341 | \& } |
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342 | .Ve |
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343 | .Sp |
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344 | .Vb 2 |
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345 | \& ... |
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346 | \& ev_set_allocator (persistent_realloc); |
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347 | .Ve |
229 | .IP "ev_set_syserr_cb (void (*cb)(const char *msg));" 4 |
348 | .IP "ev_set_syserr_cb (void (*cb)(const char *msg));" 4 |
230 | .IX Item "ev_set_syserr_cb (void (*cb)(const char *msg));" |
349 | .IX Item "ev_set_syserr_cb (void (*cb)(const char *msg));" |
231 | Set the callback function to call on a retryable syscall error (such |
350 | Set the callback function to call on a retryable syscall error (such |
232 | as failed select, poll, epoll_wait). The message is a printable string |
351 | as failed select, poll, epoll_wait). The message is a printable string |
233 | indicating the system call or subsystem causing the problem. If this |
352 | indicating the system call or subsystem causing the problem. If this |
234 | callback is set, then libev will expect it to remedy the sitution, no |
353 | callback is set, then libev will expect it to remedy the sitution, no |
235 | matter what, when it returns. That is, libev will generally retry the |
354 | matter what, when it returns. That is, libev will generally retry the |
236 | requested operation, or, if the condition doesn't go away, do bad stuff |
355 | requested operation, or, if the condition doesn't go away, do bad stuff |
237 | (such as abort). |
356 | (such as abort). |
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357 | .Sp |
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358 | Example: This is basically the same thing that libev does internally, too. |
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359 | .Sp |
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360 | .Vb 6 |
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361 | \& static void |
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362 | \& fatal_error (const char *msg) |
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363 | \& { |
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364 | \& perror (msg); |
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365 | \& abort (); |
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366 | \& } |
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367 | .Ve |
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368 | .Sp |
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369 | .Vb 2 |
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370 | \& ... |
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371 | \& ev_set_syserr_cb (fatal_error); |
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372 | .Ve |
238 | .SH "FUNCTIONS CONTROLLING THE EVENT LOOP" |
373 | .SH "FUNCTIONS CONTROLLING THE EVENT LOOP" |
239 | .IX Header "FUNCTIONS CONTROLLING THE EVENT LOOP" |
374 | .IX Header "FUNCTIONS CONTROLLING THE EVENT LOOP" |
240 | An event loop is described by a \f(CW\*(C`struct ev_loop *\*(C'\fR. The library knows two |
375 | An event loop is described by a \f(CW\*(C`struct ev_loop *\*(C'\fR. The library knows two |
241 | types of such loops, the \fIdefault\fR loop, which supports signals and child |
376 | types of such loops, the \fIdefault\fR loop, which supports signals and child |
242 | events, and dynamically created loops which do not. |
377 | events, and dynamically created loops which do not. |
… | |
… | |
256 | .Sp |
391 | .Sp |
257 | If you don't know what event loop to use, use the one returned from this |
392 | If you don't know what event loop to use, use the one returned from this |
258 | function. |
393 | function. |
259 | .Sp |
394 | .Sp |
260 | The flags argument can be used to specify special behaviour or specific |
395 | The flags argument can be used to specify special behaviour or specific |
261 | backends to use, and is usually specified as \f(CW0\fR (or \s-1EVFLAG_AUTO\s0). |
396 | backends to use, and is usually specified as \f(CW0\fR (or \f(CW\*(C`EVFLAG_AUTO\*(C'\fR). |
262 | .Sp |
397 | .Sp |
263 | It supports the following flags: |
398 | The following flags are supported: |
264 | .RS 4 |
399 | .RS 4 |
265 | .ie n .IP """EVFLAG_AUTO""" 4 |
400 | .ie n .IP """EVFLAG_AUTO""" 4 |
266 | .el .IP "\f(CWEVFLAG_AUTO\fR" 4 |
401 | .el .IP "\f(CWEVFLAG_AUTO\fR" 4 |
267 | .IX Item "EVFLAG_AUTO" |
402 | .IX Item "EVFLAG_AUTO" |
268 | The default flags value. Use this if you have no clue (it's the right |
403 | The default flags value. Use this if you have no clue (it's the right |
… | |
… | |
302 | While stopping and starting an I/O watcher in the same iteration will |
437 | While stopping and starting an I/O watcher in the same iteration will |
303 | result in some caching, there is still a syscall per such incident |
438 | result in some caching, there is still a syscall per such incident |
304 | (because the fd could point to a different file description now), so its |
439 | (because the fd could point to a different file description now), so its |
305 | best to avoid that. Also, \fIdup()\fRed file descriptors might not work very |
440 | best to avoid that. Also, \fIdup()\fRed file descriptors might not work very |
306 | well if you register events for both fds. |
441 | well if you register events for both fds. |
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442 | .Sp |
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443 | Please note that epoll sometimes generates spurious notifications, so you |
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444 | need to use non-blocking I/O or other means to avoid blocking when no data |
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445 | (or space) is available. |
307 | .ie n .IP """EVBACKEND_KQUEUE"" (value 8, most \s-1BSD\s0 clones)" 4 |
446 | .ie n .IP """EVBACKEND_KQUEUE"" (value 8, most \s-1BSD\s0 clones)" 4 |
308 | .el .IP "\f(CWEVBACKEND_KQUEUE\fR (value 8, most \s-1BSD\s0 clones)" 4 |
447 | .el .IP "\f(CWEVBACKEND_KQUEUE\fR (value 8, most \s-1BSD\s0 clones)" 4 |
309 | .IX Item "EVBACKEND_KQUEUE (value 8, most BSD clones)" |
448 | .IX Item "EVBACKEND_KQUEUE (value 8, most BSD clones)" |
310 | Kqueue deserves special mention, as at the time of this writing, it |
449 | Kqueue deserves special mention, as at the time of this writing, it |
311 | was broken on all BSDs except NetBSD (usually it doesn't work with |
450 | was broken on all BSDs except NetBSD (usually it doesn't work with |
312 | anything but sockets and pipes, except on Darwin, where of course its |
451 | anything but sockets and pipes, except on Darwin, where of course its |
313 | completely useless). For this reason its not being \*(L"autodetected\*(R" unless |
452 | completely useless). For this reason its not being \*(L"autodetected\*(R" |
314 | you explicitly specify the flags (i.e. you don't use \s-1EVFLAG_AUTO\s0). |
453 | unless you explicitly specify it explicitly in the flags (i.e. using |
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454 | \&\f(CW\*(C`EVBACKEND_KQUEUE\*(C'\fR). |
315 | .Sp |
455 | .Sp |
316 | It scales in the same way as the epoll backend, but the interface to the |
456 | It scales in the same way as the epoll backend, but the interface to the |
317 | kernel is more efficient (which says nothing about its actual speed, of |
457 | kernel is more efficient (which says nothing about its actual speed, of |
318 | course). While starting and stopping an I/O watcher does not cause an |
458 | course). While starting and stopping an I/O watcher does not cause an |
319 | extra syscall as with epoll, it still adds up to four event changes per |
459 | extra syscall as with epoll, it still adds up to four event changes per |
… | |
… | |
325 | .ie n .IP """EVBACKEND_PORT"" (value 32, Solaris 10)" 4 |
465 | .ie n .IP """EVBACKEND_PORT"" (value 32, Solaris 10)" 4 |
326 | .el .IP "\f(CWEVBACKEND_PORT\fR (value 32, Solaris 10)" 4 |
466 | .el .IP "\f(CWEVBACKEND_PORT\fR (value 32, Solaris 10)" 4 |
327 | .IX Item "EVBACKEND_PORT (value 32, Solaris 10)" |
467 | .IX Item "EVBACKEND_PORT (value 32, Solaris 10)" |
328 | This uses the Solaris 10 port mechanism. As with everything on Solaris, |
468 | This uses the Solaris 10 port mechanism. As with everything on Solaris, |
329 | it's really slow, but it still scales very well (O(active_fds)). |
469 | it's really slow, but it still scales very well (O(active_fds)). |
|
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470 | .Sp |
|
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471 | Please note that solaris ports can result in a lot of spurious |
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|
472 | notifications, so you need to use non-blocking I/O or other means to avoid |
|
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473 | blocking when no data (or space) is available. |
330 | .ie n .IP """EVBACKEND_ALL""" 4 |
474 | .ie n .IP """EVBACKEND_ALL""" 4 |
331 | .el .IP "\f(CWEVBACKEND_ALL\fR" 4 |
475 | .el .IP "\f(CWEVBACKEND_ALL\fR" 4 |
332 | .IX Item "EVBACKEND_ALL" |
476 | .IX Item "EVBACKEND_ALL" |
333 | Try all backends (even potentially broken ones that wouldn't be tried |
477 | Try all backends (even potentially broken ones that wouldn't be tried |
334 | with \f(CW\*(C`EVFLAG_AUTO\*(C'\fR). Since this is a mask, you can do stuff such as |
478 | with \f(CW\*(C`EVFLAG_AUTO\*(C'\fR). Since this is a mask, you can do stuff such as |
… | |
… | |
338 | .Sp |
482 | .Sp |
339 | If one or more of these are ored into the flags value, then only these |
483 | If one or more of these are ored into the flags value, then only these |
340 | backends will be tried (in the reverse order as given here). If none are |
484 | backends will be tried (in the reverse order as given here). If none are |
341 | specified, most compiled-in backend will be tried, usually in reverse |
485 | specified, most compiled-in backend will be tried, usually in reverse |
342 | order of their flag values :) |
486 | order of their flag values :) |
|
|
487 | .Sp |
|
|
488 | The most typical usage is like this: |
|
|
489 | .Sp |
|
|
490 | .Vb 2 |
|
|
491 | \& if (!ev_default_loop (0)) |
|
|
492 | \& fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?"); |
|
|
493 | .Ve |
|
|
494 | .Sp |
|
|
495 | Restrict libev to the select and poll backends, and do not allow |
|
|
496 | environment settings to be taken into account: |
|
|
497 | .Sp |
|
|
498 | .Vb 1 |
|
|
499 | \& ev_default_loop (EVBACKEND_POLL | EVBACKEND_SELECT | EVFLAG_NOENV); |
|
|
500 | .Ve |
|
|
501 | .Sp |
|
|
502 | Use whatever libev has to offer, but make sure that kqueue is used if |
|
|
503 | available (warning, breaks stuff, best use only with your own private |
|
|
504 | event loop and only if you know the \s-1OS\s0 supports your types of fds): |
|
|
505 | .Sp |
|
|
506 | .Vb 1 |
|
|
507 | \& ev_default_loop (ev_recommended_backends () | EVBACKEND_KQUEUE); |
|
|
508 | .Ve |
343 | .RE |
509 | .RE |
344 | .IP "struct ev_loop *ev_loop_new (unsigned int flags)" 4 |
510 | .IP "struct ev_loop *ev_loop_new (unsigned int flags)" 4 |
345 | .IX Item "struct ev_loop *ev_loop_new (unsigned int flags)" |
511 | .IX Item "struct ev_loop *ev_loop_new (unsigned int flags)" |
346 | Similar to \f(CW\*(C`ev_default_loop\*(C'\fR, but always creates a new event loop that is |
512 | Similar to \f(CW\*(C`ev_default_loop\*(C'\fR, but always creates a new event loop that is |
347 | always distinct from the default loop. Unlike the default loop, it cannot |
513 | always distinct from the default loop. Unlike the default loop, it cannot |
348 | handle signal and child watchers, and attempts to do so will be greeted by |
514 | handle signal and child watchers, and attempts to do so will be greeted by |
349 | undefined behaviour (or a failed assertion if assertions are enabled). |
515 | undefined behaviour (or a failed assertion if assertions are enabled). |
|
|
516 | .Sp |
|
|
517 | Example: Try to create a event loop that uses epoll and nothing else. |
|
|
518 | .Sp |
|
|
519 | .Vb 3 |
|
|
520 | \& struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
|
|
521 | \& if (!epoller) |
|
|
522 | \& fatal ("no epoll found here, maybe it hides under your chair"); |
|
|
523 | .Ve |
350 | .IP "ev_default_destroy ()" 4 |
524 | .IP "ev_default_destroy ()" 4 |
351 | .IX Item "ev_default_destroy ()" |
525 | .IX Item "ev_default_destroy ()" |
352 | Destroys the default loop again (frees all memory and kernel state |
526 | Destroys the default loop again (frees all memory and kernel state |
353 | etc.). This stops all registered event watchers (by not touching them in |
527 | etc.). None of the active event watchers will be stopped in the normal |
354 | any way whatsoever, although you cannot rely on this :). |
528 | sense, so e.g. \f(CW\*(C`ev_is_active\*(C'\fR might still return true. It is your |
|
|
529 | responsibility to either stop all watchers cleanly yoursef \fIbefore\fR |
|
|
530 | calling this function, or cope with the fact afterwards (which is usually |
|
|
531 | the easiest thing, youc na just ignore the watchers and/or \f(CW\*(C`free ()\*(C'\fR them |
|
|
532 | for example). |
355 | .IP "ev_loop_destroy (loop)" 4 |
533 | .IP "ev_loop_destroy (loop)" 4 |
356 | .IX Item "ev_loop_destroy (loop)" |
534 | .IX Item "ev_loop_destroy (loop)" |
357 | Like \f(CW\*(C`ev_default_destroy\*(C'\fR, but destroys an event loop created by an |
535 | Like \f(CW\*(C`ev_default_destroy\*(C'\fR, but destroys an event loop created by an |
358 | earlier call to \f(CW\*(C`ev_loop_new\*(C'\fR. |
536 | earlier call to \f(CW\*(C`ev_loop_new\*(C'\fR. |
359 | .IP "ev_default_fork ()" 4 |
537 | .IP "ev_default_fork ()" 4 |
… | |
… | |
388 | Returns one of the \f(CW\*(C`EVBACKEND_*\*(C'\fR flags indicating the event backend in |
566 | Returns one of the \f(CW\*(C`EVBACKEND_*\*(C'\fR flags indicating the event backend in |
389 | use. |
567 | use. |
390 | .IP "ev_tstamp ev_now (loop)" 4 |
568 | .IP "ev_tstamp ev_now (loop)" 4 |
391 | .IX Item "ev_tstamp ev_now (loop)" |
569 | .IX Item "ev_tstamp ev_now (loop)" |
392 | Returns the current \*(L"event loop time\*(R", which is the time the event loop |
570 | Returns the current \*(L"event loop time\*(R", which is the time the event loop |
393 | got events and started processing them. This timestamp does not change |
571 | received events and started processing them. This timestamp does not |
394 | as long as callbacks are being processed, and this is also the base time |
572 | change as long as callbacks are being processed, and this is also the base |
395 | used for relative timers. You can treat it as the timestamp of the event |
573 | time used for relative timers. You can treat it as the timestamp of the |
396 | occuring (or more correctly, the mainloop finding out about it). |
574 | event occuring (or more correctly, libev finding out about it). |
397 | .IP "ev_loop (loop, int flags)" 4 |
575 | .IP "ev_loop (loop, int flags)" 4 |
398 | .IX Item "ev_loop (loop, int flags)" |
576 | .IX Item "ev_loop (loop, int flags)" |
399 | Finally, this is it, the event handler. This function usually is called |
577 | Finally, this is it, the event handler. This function usually is called |
400 | after you initialised all your watchers and you want to start handling |
578 | after you initialised all your watchers and you want to start handling |
401 | events. |
579 | events. |
402 | .Sp |
580 | .Sp |
403 | If the flags argument is specified as 0, it will not return until either |
581 | If the flags argument is specified as \f(CW0\fR, it will not return until |
404 | no event watchers are active anymore or \f(CW\*(C`ev_unloop\*(C'\fR was called. |
582 | either no event watchers are active anymore or \f(CW\*(C`ev_unloop\*(C'\fR was called. |
|
|
583 | .Sp |
|
|
584 | Please note that an explicit \f(CW\*(C`ev_unloop\*(C'\fR is usually better than |
|
|
585 | relying on all watchers to be stopped when deciding when a program has |
|
|
586 | finished (especially in interactive programs), but having a program that |
|
|
587 | automatically loops as long as it has to and no longer by virtue of |
|
|
588 | relying on its watchers stopping correctly is a thing of beauty. |
405 | .Sp |
589 | .Sp |
406 | A flags value of \f(CW\*(C`EVLOOP_NONBLOCK\*(C'\fR will look for new events, will handle |
590 | A flags value of \f(CW\*(C`EVLOOP_NONBLOCK\*(C'\fR will look for new events, will handle |
407 | those events and any outstanding ones, but will not block your process in |
591 | those events and any outstanding ones, but will not block your process in |
408 | case there are no events and will return after one iteration of the loop. |
592 | case there are no events and will return after one iteration of the loop. |
409 | .Sp |
593 | .Sp |
410 | A flags value of \f(CW\*(C`EVLOOP_ONESHOT\*(C'\fR will look for new events (waiting if |
594 | A flags value of \f(CW\*(C`EVLOOP_ONESHOT\*(C'\fR will look for new events (waiting if |
411 | neccessary) and will handle those and any outstanding ones. It will block |
595 | neccessary) and will handle those and any outstanding ones. It will block |
412 | your process until at least one new event arrives, and will return after |
596 | your process until at least one new event arrives, and will return after |
413 | one iteration of the loop. |
597 | one iteration of the loop. This is useful if you are waiting for some |
|
|
598 | external event in conjunction with something not expressible using other |
|
|
599 | libev watchers. However, a pair of \f(CW\*(C`ev_prepare\*(C'\fR/\f(CW\*(C`ev_check\*(C'\fR watchers is |
|
|
600 | usually a better approach for this kind of thing. |
414 | .Sp |
601 | .Sp |
415 | This flags value could be used to implement alternative looping |
|
|
416 | constructs, but the \f(CW\*(C`prepare\*(C'\fR and \f(CW\*(C`check\*(C'\fR watchers provide a better and |
|
|
417 | more generic mechanism. |
|
|
418 | .Sp |
|
|
419 | Here are the gory details of what ev_loop does: |
602 | Here are the gory details of what \f(CW\*(C`ev_loop\*(C'\fR does: |
420 | .Sp |
603 | .Sp |
421 | .Vb 15 |
604 | .Vb 18 |
422 | \& 1. If there are no active watchers (reference count is zero), return. |
605 | \& * If there are no active watchers (reference count is zero), return. |
423 | \& 2. Queue and immediately call all prepare watchers. |
606 | \& - Queue prepare watchers and then call all outstanding watchers. |
424 | \& 3. If we have been forked, recreate the kernel state. |
607 | \& - If we have been forked, recreate the kernel state. |
425 | \& 4. Update the kernel state with all outstanding changes. |
608 | \& - Update the kernel state with all outstanding changes. |
426 | \& 5. Update the "event loop time". |
609 | \& - Update the "event loop time". |
427 | \& 6. Calculate for how long to block. |
610 | \& - Calculate for how long to block. |
428 | \& 7. Block the process, waiting for events. |
611 | \& - Block the process, waiting for any events. |
|
|
612 | \& - Queue all outstanding I/O (fd) events. |
429 | \& 8. Update the "event loop time" and do time jump handling. |
613 | \& - Update the "event loop time" and do time jump handling. |
430 | \& 9. Queue all outstanding timers. |
614 | \& - Queue all outstanding timers. |
431 | \& 10. Queue all outstanding periodics. |
615 | \& - Queue all outstanding periodics. |
432 | \& 11. If no events are pending now, queue all idle watchers. |
616 | \& - If no events are pending now, queue all idle watchers. |
433 | \& 12. Queue all check watchers. |
617 | \& - Queue all check watchers. |
434 | \& 13. Call all queued watchers in reverse order (i.e. check watchers first). |
618 | \& - Call all queued watchers in reverse order (i.e. check watchers first). |
|
|
619 | \& Signals and child watchers are implemented as I/O watchers, and will |
|
|
620 | \& be handled here by queueing them when their watcher gets executed. |
435 | \& 14. If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
621 | \& - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
436 | \& was used, return, otherwise continue with step #1. |
622 | \& were used, return, otherwise continue with step *. |
|
|
623 | .Ve |
|
|
624 | .Sp |
|
|
625 | Example: Queue some jobs and then loop until no events are outsanding |
|
|
626 | anymore. |
|
|
627 | .Sp |
|
|
628 | .Vb 4 |
|
|
629 | \& ... queue jobs here, make sure they register event watchers as long |
|
|
630 | \& ... as they still have work to do (even an idle watcher will do..) |
|
|
631 | \& ev_loop (my_loop, 0); |
|
|
632 | \& ... jobs done. yeah! |
437 | .Ve |
633 | .Ve |
438 | .IP "ev_unloop (loop, how)" 4 |
634 | .IP "ev_unloop (loop, how)" 4 |
439 | .IX Item "ev_unloop (loop, how)" |
635 | .IX Item "ev_unloop (loop, how)" |
440 | Can be used to make a call to \f(CW\*(C`ev_loop\*(C'\fR return early (but only after it |
636 | Can be used to make a call to \f(CW\*(C`ev_loop\*(C'\fR return early (but only after it |
441 | has processed all outstanding events). The \f(CW\*(C`how\*(C'\fR argument must be either |
637 | has processed all outstanding events). The \f(CW\*(C`how\*(C'\fR argument must be either |
… | |
… | |
455 | example, libev itself uses this for its internal signal pipe: It is not |
651 | example, libev itself uses this for its internal signal pipe: It is not |
456 | visible to the libev user and should not keep \f(CW\*(C`ev_loop\*(C'\fR from exiting if |
652 | visible to the libev user and should not keep \f(CW\*(C`ev_loop\*(C'\fR from exiting if |
457 | no event watchers registered by it are active. It is also an excellent |
653 | no event watchers registered by it are active. It is also an excellent |
458 | way to do this for generic recurring timers or from within third-party |
654 | way to do this for generic recurring timers or from within third-party |
459 | libraries. Just remember to \fIunref after start\fR and \fIref before stop\fR. |
655 | libraries. Just remember to \fIunref after start\fR and \fIref before stop\fR. |
|
|
656 | .Sp |
|
|
657 | Example: Create a signal watcher, but keep it from keeping \f(CW\*(C`ev_loop\*(C'\fR |
|
|
658 | running when nothing else is active. |
|
|
659 | .Sp |
|
|
660 | .Vb 4 |
|
|
661 | \& struct ev_signal exitsig; |
|
|
662 | \& ev_signal_init (&exitsig, sig_cb, SIGINT); |
|
|
663 | \& ev_signal_start (loop, &exitsig); |
|
|
664 | \& evf_unref (loop); |
|
|
665 | .Ve |
|
|
666 | .Sp |
|
|
667 | Example: For some weird reason, unregister the above signal handler again. |
|
|
668 | .Sp |
|
|
669 | .Vb 2 |
|
|
670 | \& ev_ref (loop); |
|
|
671 | \& ev_signal_stop (loop, &exitsig); |
|
|
672 | .Ve |
460 | .SH "ANATOMY OF A WATCHER" |
673 | .SH "ANATOMY OF A WATCHER" |
461 | .IX Header "ANATOMY OF A WATCHER" |
674 | .IX Header "ANATOMY OF A WATCHER" |
462 | A watcher is a structure that you create and register to record your |
675 | A watcher is a structure that you create and register to record your |
463 | interest in some event. For instance, if you want to wait for \s-1STDIN\s0 to |
676 | interest in some event. For instance, if you want to wait for \s-1STDIN\s0 to |
464 | become readable, you would create an \f(CW\*(C`ev_io\*(C'\fR watcher for that: |
677 | become readable, you would create an \f(CW\*(C`ev_io\*(C'\fR watcher for that: |
… | |
… | |
500 | *)\*(C'\fR), and you can stop watching for events at any time by calling the |
713 | *)\*(C'\fR), and you can stop watching for events at any time by calling the |
501 | corresponding stop function (\f(CW\*(C`ev_<type>_stop (loop, watcher *)\*(C'\fR. |
714 | corresponding stop function (\f(CW\*(C`ev_<type>_stop (loop, watcher *)\*(C'\fR. |
502 | .PP |
715 | .PP |
503 | As long as your watcher is active (has been started but not stopped) you |
716 | As long as your watcher is active (has been started but not stopped) you |
504 | must not touch the values stored in it. Most specifically you must never |
717 | must not touch the values stored in it. Most specifically you must never |
505 | reinitialise it or call its set macro. |
718 | reinitialise it or call its \f(CW\*(C`set\*(C'\fR macro. |
506 | .PP |
|
|
507 | You can check whether an event is active by calling the \f(CW\*(C`ev_is_active |
|
|
508 | (watcher *)\*(C'\fR macro. To see whether an event is outstanding (but the |
|
|
509 | callback for it has not been called yet) you can use the \f(CW\*(C`ev_is_pending |
|
|
510 | (watcher *)\*(C'\fR macro. |
|
|
511 | .PP |
719 | .PP |
512 | Each and every callback receives the event loop pointer as first, the |
720 | Each and every callback receives the event loop pointer as first, the |
513 | registered watcher structure as second, and a bitset of received events as |
721 | registered watcher structure as second, and a bitset of received events as |
514 | third argument. |
722 | third argument. |
515 | .PP |
723 | .PP |
… | |
… | |
540 | The signal specified in the \f(CW\*(C`ev_signal\*(C'\fR watcher has been received by a thread. |
748 | The signal specified in the \f(CW\*(C`ev_signal\*(C'\fR watcher has been received by a thread. |
541 | .ie n .IP """EV_CHILD""" 4 |
749 | .ie n .IP """EV_CHILD""" 4 |
542 | .el .IP "\f(CWEV_CHILD\fR" 4 |
750 | .el .IP "\f(CWEV_CHILD\fR" 4 |
543 | .IX Item "EV_CHILD" |
751 | .IX Item "EV_CHILD" |
544 | The pid specified in the \f(CW\*(C`ev_child\*(C'\fR watcher has received a status change. |
752 | The pid specified in the \f(CW\*(C`ev_child\*(C'\fR watcher has received a status change. |
|
|
753 | .ie n .IP """EV_STAT""" 4 |
|
|
754 | .el .IP "\f(CWEV_STAT\fR" 4 |
|
|
755 | .IX Item "EV_STAT" |
|
|
756 | The path specified in the \f(CW\*(C`ev_stat\*(C'\fR watcher changed its attributes somehow. |
545 | .ie n .IP """EV_IDLE""" 4 |
757 | .ie n .IP """EV_IDLE""" 4 |
546 | .el .IP "\f(CWEV_IDLE\fR" 4 |
758 | .el .IP "\f(CWEV_IDLE\fR" 4 |
547 | .IX Item "EV_IDLE" |
759 | .IX Item "EV_IDLE" |
548 | The \f(CW\*(C`ev_idle\*(C'\fR watcher has determined that you have nothing better to do. |
760 | The \f(CW\*(C`ev_idle\*(C'\fR watcher has determined that you have nothing better to do. |
549 | .ie n .IP """EV_PREPARE""" 4 |
761 | .ie n .IP """EV_PREPARE""" 4 |
… | |
… | |
559 | \&\f(CW\*(C`ev_loop\*(C'\fR has gathered them, but before it invokes any callbacks for any |
771 | \&\f(CW\*(C`ev_loop\*(C'\fR has gathered them, but before it invokes any callbacks for any |
560 | received events. Callbacks of both watcher types can start and stop as |
772 | received events. Callbacks of both watcher types can start and stop as |
561 | many watchers as they want, and all of them will be taken into account |
773 | many watchers as they want, and all of them will be taken into account |
562 | (for example, a \f(CW\*(C`ev_prepare\*(C'\fR watcher might start an idle watcher to keep |
774 | (for example, a \f(CW\*(C`ev_prepare\*(C'\fR watcher might start an idle watcher to keep |
563 | \&\f(CW\*(C`ev_loop\*(C'\fR from blocking). |
775 | \&\f(CW\*(C`ev_loop\*(C'\fR from blocking). |
|
|
776 | .ie n .IP """EV_EMBED""" 4 |
|
|
777 | .el .IP "\f(CWEV_EMBED\fR" 4 |
|
|
778 | .IX Item "EV_EMBED" |
|
|
779 | The embedded event loop specified in the \f(CW\*(C`ev_embed\*(C'\fR watcher needs attention. |
|
|
780 | .ie n .IP """EV_FORK""" 4 |
|
|
781 | .el .IP "\f(CWEV_FORK\fR" 4 |
|
|
782 | .IX Item "EV_FORK" |
|
|
783 | The event loop has been resumed in the child process after fork (see |
|
|
784 | \&\f(CW\*(C`ev_fork\*(C'\fR). |
564 | .ie n .IP """EV_ERROR""" 4 |
785 | .ie n .IP """EV_ERROR""" 4 |
565 | .el .IP "\f(CWEV_ERROR\fR" 4 |
786 | .el .IP "\f(CWEV_ERROR\fR" 4 |
566 | .IX Item "EV_ERROR" |
787 | .IX Item "EV_ERROR" |
567 | An unspecified error has occured, the watcher has been stopped. This might |
788 | An unspecified error has occured, the watcher has been stopped. This might |
568 | happen because the watcher could not be properly started because libev |
789 | happen because the watcher could not be properly started because libev |
… | |
… | |
573 | Libev will usually signal a few \*(L"dummy\*(R" events together with an error, |
794 | Libev will usually signal a few \*(L"dummy\*(R" events together with an error, |
574 | for example it might indicate that a fd is readable or writable, and if |
795 | for example it might indicate that a fd is readable or writable, and if |
575 | your callbacks is well-written it can just attempt the operation and cope |
796 | your callbacks is well-written it can just attempt the operation and cope |
576 | with the error from \fIread()\fR or \fIwrite()\fR. This will not work in multithreaded |
797 | with the error from \fIread()\fR or \fIwrite()\fR. This will not work in multithreaded |
577 | programs, though, so beware. |
798 | programs, though, so beware. |
|
|
799 | .Sh "\s-1GENERIC\s0 \s-1WATCHER\s0 \s-1FUNCTIONS\s0" |
|
|
800 | .IX Subsection "GENERIC WATCHER FUNCTIONS" |
|
|
801 | In the following description, \f(CW\*(C`TYPE\*(C'\fR stands for the watcher type, |
|
|
802 | 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. |
|
|
803 | .ie n .IP """ev_init"" (ev_TYPE *watcher, callback)" 4 |
|
|
804 | .el .IP "\f(CWev_init\fR (ev_TYPE *watcher, callback)" 4 |
|
|
805 | .IX Item "ev_init (ev_TYPE *watcher, callback)" |
|
|
806 | This macro initialises the generic portion of a watcher. The contents |
|
|
807 | of the watcher object can be arbitrary (so \f(CW\*(C`malloc\*(C'\fR will do). Only |
|
|
808 | the generic parts of the watcher are initialised, you \fIneed\fR to call |
|
|
809 | the type-specific \f(CW\*(C`ev_TYPE_set\*(C'\fR macro afterwards to initialise the |
|
|
810 | type-specific parts. For each type there is also a \f(CW\*(C`ev_TYPE_init\*(C'\fR macro |
|
|
811 | which rolls both calls into one. |
|
|
812 | .Sp |
|
|
813 | You can reinitialise a watcher at any time as long as it has been stopped |
|
|
814 | (or never started) and there are no pending events outstanding. |
|
|
815 | .Sp |
|
|
816 | The callback is always of type \f(CW\*(C`void (*)(ev_loop *loop, ev_TYPE *watcher, |
|
|
817 | int revents)\*(C'\fR. |
|
|
818 | .ie n .IP """ev_TYPE_set"" (ev_TYPE *, [args])" 4 |
|
|
819 | .el .IP "\f(CWev_TYPE_set\fR (ev_TYPE *, [args])" 4 |
|
|
820 | .IX Item "ev_TYPE_set (ev_TYPE *, [args])" |
|
|
821 | This macro initialises the type-specific parts of a watcher. You need to |
|
|
822 | call \f(CW\*(C`ev_init\*(C'\fR at least once before you call this macro, but you can |
|
|
823 | call \f(CW\*(C`ev_TYPE_set\*(C'\fR any number of times. You must not, however, call this |
|
|
824 | macro on a watcher that is active (it can be pending, however, which is a |
|
|
825 | difference to the \f(CW\*(C`ev_init\*(C'\fR macro). |
|
|
826 | .Sp |
|
|
827 | Although some watcher types do not have type-specific arguments |
|
|
828 | (e.g. \f(CW\*(C`ev_prepare\*(C'\fR) you still need to call its \f(CW\*(C`set\*(C'\fR macro. |
|
|
829 | .ie n .IP """ev_TYPE_init"" (ev_TYPE *watcher, callback, [args])" 4 |
|
|
830 | .el .IP "\f(CWev_TYPE_init\fR (ev_TYPE *watcher, callback, [args])" 4 |
|
|
831 | .IX Item "ev_TYPE_init (ev_TYPE *watcher, callback, [args])" |
|
|
832 | This convinience macro rolls both \f(CW\*(C`ev_init\*(C'\fR and \f(CW\*(C`ev_TYPE_set\*(C'\fR macro |
|
|
833 | calls into a single call. This is the most convinient method to initialise |
|
|
834 | a watcher. The same limitations apply, of course. |
|
|
835 | .ie n .IP """ev_TYPE_start"" (loop *, ev_TYPE *watcher)" 4 |
|
|
836 | .el .IP "\f(CWev_TYPE_start\fR (loop *, ev_TYPE *watcher)" 4 |
|
|
837 | .IX Item "ev_TYPE_start (loop *, ev_TYPE *watcher)" |
|
|
838 | Starts (activates) the given watcher. Only active watchers will receive |
|
|
839 | events. If the watcher is already active nothing will happen. |
|
|
840 | .ie n .IP """ev_TYPE_stop"" (loop *, ev_TYPE *watcher)" 4 |
|
|
841 | .el .IP "\f(CWev_TYPE_stop\fR (loop *, ev_TYPE *watcher)" 4 |
|
|
842 | .IX Item "ev_TYPE_stop (loop *, ev_TYPE *watcher)" |
|
|
843 | Stops the given watcher again (if active) and clears the pending |
|
|
844 | status. It is possible that stopped watchers are pending (for example, |
|
|
845 | non-repeating timers are being stopped when they become pending), but |
|
|
846 | \&\f(CW\*(C`ev_TYPE_stop\*(C'\fR ensures that the watcher is neither active nor pending. If |
|
|
847 | you want to free or reuse the memory used by the watcher it is therefore a |
|
|
848 | good idea to always call its \f(CW\*(C`ev_TYPE_stop\*(C'\fR function. |
|
|
849 | .IP "bool ev_is_active (ev_TYPE *watcher)" 4 |
|
|
850 | .IX Item "bool ev_is_active (ev_TYPE *watcher)" |
|
|
851 | Returns a true value iff the watcher is active (i.e. it has been started |
|
|
852 | and not yet been stopped). As long as a watcher is active you must not modify |
|
|
853 | it. |
|
|
854 | .IP "bool ev_is_pending (ev_TYPE *watcher)" 4 |
|
|
855 | .IX Item "bool ev_is_pending (ev_TYPE *watcher)" |
|
|
856 | Returns a true value iff the watcher is pending, (i.e. it has outstanding |
|
|
857 | events but its callback has not yet been invoked). As long as a watcher |
|
|
858 | is pending (but not active) you must not call an init function on it (but |
|
|
859 | \&\f(CW\*(C`ev_TYPE_set\*(C'\fR is safe) and you must make sure the watcher is available to |
|
|
860 | libev (e.g. you cnanot \f(CW\*(C`free ()\*(C'\fR it). |
|
|
861 | .IP "callback = ev_cb (ev_TYPE *watcher)" 4 |
|
|
862 | .IX Item "callback = ev_cb (ev_TYPE *watcher)" |
|
|
863 | Returns the callback currently set on the watcher. |
|
|
864 | .IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 |
|
|
865 | .IX Item "ev_cb_set (ev_TYPE *watcher, callback)" |
|
|
866 | Change the callback. You can change the callback at virtually any time |
|
|
867 | (modulo threads). |
578 | .Sh "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0" |
868 | .Sh "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0" |
579 | .IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER" |
869 | .IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER" |
580 | Each watcher has, by default, a member \f(CW\*(C`void *data\*(C'\fR that you can change |
870 | Each watcher has, by default, a member \f(CW\*(C`void *data\*(C'\fR that you can change |
581 | and read at any time, libev will completely ignore it. This can be used |
871 | and read at any time, libev will completely ignore it. This can be used |
582 | to associate arbitrary data with your watcher. If you need more data and |
872 | to associate arbitrary data with your watcher. If you need more data and |
… | |
… | |
608 | More interesting and less C\-conformant ways of catsing your callback type |
898 | More interesting and less C\-conformant ways of catsing your callback type |
609 | have been omitted.... |
899 | have been omitted.... |
610 | .SH "WATCHER TYPES" |
900 | .SH "WATCHER TYPES" |
611 | .IX Header "WATCHER TYPES" |
901 | .IX Header "WATCHER TYPES" |
612 | This section describes each watcher in detail, but will not repeat |
902 | This section describes each watcher in detail, but will not repeat |
613 | information given in the last section. |
903 | information given in the last section. Any initialisation/set macros, |
|
|
904 | functions and members specific to the watcher type are explained. |
|
|
905 | .PP |
|
|
906 | Members are additionally marked with either \fI[read\-only]\fR, meaning that, |
|
|
907 | while the watcher is active, you can look at the member and expect some |
|
|
908 | sensible content, but you must not modify it (you can modify it while the |
|
|
909 | watcher is stopped to your hearts content), or \fI[read\-write]\fR, which |
|
|
910 | means you can expect it to have some sensible content while the watcher |
|
|
911 | is active, but you can also modify it. Modifying it may not do something |
|
|
912 | sensible or take immediate effect (or do anything at all), but libev will |
|
|
913 | not crash or malfunction in any way. |
614 | .ie n .Sh """ev_io"" \- is this file descriptor readable or writable" |
914 | .ie n .Sh """ev_io"" \- is this file descriptor readable or writable?" |
615 | .el .Sh "\f(CWev_io\fP \- is this file descriptor readable or writable" |
915 | .el .Sh "\f(CWev_io\fP \- is this file descriptor readable or writable?" |
616 | .IX Subsection "ev_io - is this file descriptor readable or writable" |
916 | .IX Subsection "ev_io - is this file descriptor readable or writable?" |
617 | I/O watchers check whether a file descriptor is readable or writable |
917 | I/O watchers check whether a file descriptor is readable or writable |
618 | in each iteration of the event loop (This behaviour is called |
918 | in each iteration of the event loop, or, more precisely, when reading |
619 | level-triggering because you keep receiving events as long as the |
919 | would not block the process and writing would at least be able to write |
620 | condition persists. Remember you can stop the watcher if you don't want to |
920 | some data. This behaviour is called level-triggering because you keep |
621 | act on the event and neither want to receive future events). |
921 | receiving events as long as the condition persists. Remember you can stop |
|
|
922 | the watcher if you don't want to act on the event and neither want to |
|
|
923 | receive future events. |
622 | .PP |
924 | .PP |
623 | In general you can register as many read and/or write event watchers per |
925 | In general you can register as many read and/or write event watchers per |
624 | fd as you want (as long as you don't confuse yourself). Setting all file |
926 | fd as you want (as long as you don't confuse yourself). Setting all file |
625 | descriptors to non-blocking mode is also usually a good idea (but not |
927 | descriptors to non-blocking mode is also usually a good idea (but not |
626 | required if you know what you are doing). |
928 | required if you know what you are doing). |
627 | .PP |
929 | .PP |
628 | You have to be careful with dup'ed file descriptors, though. Some backends |
930 | You have to be careful with dup'ed file descriptors, though. Some backends |
629 | (the linux epoll backend is a notable example) cannot handle dup'ed file |
931 | (the linux epoll backend is a notable example) cannot handle dup'ed file |
630 | descriptors correctly if you register interest in two or more fds pointing |
932 | descriptors correctly if you register interest in two or more fds pointing |
631 | to the same underlying file/socket etc. description (that is, they share |
933 | to the same underlying file/socket/etc. description (that is, they share |
632 | the same underlying \*(L"file open\*(R"). |
934 | the same underlying \*(L"file open\*(R"). |
633 | .PP |
935 | .PP |
634 | If you must do this, then force the use of a known-to-be-good backend |
936 | If you must do this, then force the use of a known-to-be-good backend |
635 | (at the time of this writing, this includes only \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR and |
937 | (at the time of this writing, this includes only \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR and |
636 | \&\f(CW\*(C`EVBACKEND_POLL\*(C'\fR). |
938 | \&\f(CW\*(C`EVBACKEND_POLL\*(C'\fR). |
|
|
939 | .PP |
|
|
940 | Another thing you have to watch out for is that it is quite easy to |
|
|
941 | receive \*(L"spurious\*(R" readyness notifications, that is your callback might |
|
|
942 | be called with \f(CW\*(C`EV_READ\*(C'\fR but a subsequent \f(CW\*(C`read\*(C'\fR(2) will actually block |
|
|
943 | because there is no data. Not only are some backends known to create a |
|
|
944 | lot of those (for example solaris ports), it is very easy to get into |
|
|
945 | this situation even with a relatively standard program structure. Thus |
|
|
946 | it is best to always use non-blocking I/O: An extra \f(CW\*(C`read\*(C'\fR(2) returning |
|
|
947 | \&\f(CW\*(C`EAGAIN\*(C'\fR is far preferable to a program hanging until some data arrives. |
|
|
948 | .PP |
|
|
949 | If you cannot run the fd in non-blocking mode (for example you should not |
|
|
950 | play around with an Xlib connection), then you have to seperately re-test |
|
|
951 | wether a file descriptor is really ready with a known-to-be good interface |
|
|
952 | such as poll (fortunately in our Xlib example, Xlib already does this on |
|
|
953 | its own, so its quite safe to use). |
637 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
954 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
638 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
955 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
639 | .PD 0 |
956 | .PD 0 |
640 | .IP "ev_io_set (ev_io *, int fd, int events)" 4 |
957 | .IP "ev_io_set (ev_io *, int fd, int events)" 4 |
641 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
958 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
642 | .PD |
959 | .PD |
643 | Configures an \f(CW\*(C`ev_io\*(C'\fR watcher. The fd is the file descriptor to rceeive |
960 | Configures an \f(CW\*(C`ev_io\*(C'\fR watcher. The \f(CW\*(C`fd\*(C'\fR is the file descriptor to |
644 | 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 | |
961 | rceeive events for and events is either \f(CW\*(C`EV_READ\*(C'\fR, \f(CW\*(C`EV_WRITE\*(C'\fR or |
645 | EV_WRITE\*(C'\fR to receive the given events. |
962 | \&\f(CW\*(C`EV_READ | EV_WRITE\*(C'\fR to receive the given events. |
|
|
963 | .IP "int fd [read\-only]" 4 |
|
|
964 | .IX Item "int fd [read-only]" |
|
|
965 | The file descriptor being watched. |
|
|
966 | .IP "int events [read\-only]" 4 |
|
|
967 | .IX Item "int events [read-only]" |
|
|
968 | The events being watched. |
|
|
969 | .PP |
|
|
970 | Example: Call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well |
|
|
971 | readable, but only once. Since it is likely line\-buffered, you could |
|
|
972 | attempt to read a whole line in the callback. |
|
|
973 | .PP |
|
|
974 | .Vb 6 |
|
|
975 | \& static void |
|
|
976 | \& stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
|
|
977 | \& { |
|
|
978 | \& ev_io_stop (loop, w); |
|
|
979 | \& .. read from stdin here (or from w->fd) and haqndle any I/O errors |
|
|
980 | \& } |
|
|
981 | .Ve |
|
|
982 | .PP |
|
|
983 | .Vb 6 |
|
|
984 | \& ... |
|
|
985 | \& struct ev_loop *loop = ev_default_init (0); |
|
|
986 | \& struct ev_io stdin_readable; |
|
|
987 | \& ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ); |
|
|
988 | \& ev_io_start (loop, &stdin_readable); |
|
|
989 | \& ev_loop (loop, 0); |
|
|
990 | .Ve |
646 | .ie n .Sh """ev_timer"" \- relative and optionally recurring timeouts" |
991 | .ie n .Sh """ev_timer"" \- relative and optionally repeating timeouts" |
647 | .el .Sh "\f(CWev_timer\fP \- relative and optionally recurring timeouts" |
992 | .el .Sh "\f(CWev_timer\fP \- relative and optionally repeating timeouts" |
648 | .IX Subsection "ev_timer - relative and optionally recurring timeouts" |
993 | .IX Subsection "ev_timer - relative and optionally repeating timeouts" |
649 | Timer watchers are simple relative timers that generate an event after a |
994 | Timer watchers are simple relative timers that generate an event after a |
650 | given time, and optionally repeating in regular intervals after that. |
995 | given time, and optionally repeating in regular intervals after that. |
651 | .PP |
996 | .PP |
652 | The timers are based on real time, that is, if you register an event that |
997 | The timers are based on real time, that is, if you register an event that |
653 | times out after an hour and you reset your system clock to last years |
998 | times out after an hour and you reset your system clock to last years |
… | |
… | |
693 | .Sp |
1038 | .Sp |
694 | If the timer is repeating, either start it if necessary (with the repeat |
1039 | If the timer is repeating, either start it if necessary (with the repeat |
695 | value), or reset the running timer to the repeat value. |
1040 | value), or reset the running timer to the repeat value. |
696 | .Sp |
1041 | .Sp |
697 | This sounds a bit complicated, but here is a useful and typical |
1042 | This sounds a bit complicated, but here is a useful and typical |
698 | example: Imagine you have a tcp connection and you want a so-called idle |
1043 | example: Imagine you have a tcp connection and you want a so-called |
699 | timeout, that is, you want to be called when there have been, say, 60 |
1044 | idle timeout, that is, you want to be called when there have been, |
700 | seconds of inactivity on the socket. The easiest way to do this is to |
1045 | say, 60 seconds of inactivity on the socket. The easiest way to do |
701 | configure an \f(CW\*(C`ev_timer\*(C'\fR with after=repeat=60 and calling ev_timer_again each |
1046 | this is to configure an \f(CW\*(C`ev_timer\*(C'\fR with \f(CW\*(C`after\*(C'\fR=\f(CW\*(C`repeat\*(C'\fR=\f(CW60\fR and calling |
702 | time you successfully read or write some data. If you go into an idle |
1047 | \&\f(CW\*(C`ev_timer_again\*(C'\fR each time you successfully read or write some data. If |
703 | state where you do not expect data to travel on the socket, you can stop |
1048 | you go into an idle state where you do not expect data to travel on the |
704 | the timer, and again will automatically restart it if need be. |
1049 | socket, you can stop the timer, and again will automatically restart it if |
|
|
1050 | need be. |
|
|
1051 | .Sp |
|
|
1052 | You can also ignore the \f(CW\*(C`after\*(C'\fR value and \f(CW\*(C`ev_timer_start\*(C'\fR altogether |
|
|
1053 | and only ever use the \f(CW\*(C`repeat\*(C'\fR value: |
|
|
1054 | .Sp |
|
|
1055 | .Vb 8 |
|
|
1056 | \& ev_timer_init (timer, callback, 0., 5.); |
|
|
1057 | \& ev_timer_again (loop, timer); |
|
|
1058 | \& ... |
|
|
1059 | \& timer->again = 17.; |
|
|
1060 | \& ev_timer_again (loop, timer); |
|
|
1061 | \& ... |
|
|
1062 | \& timer->again = 10.; |
|
|
1063 | \& ev_timer_again (loop, timer); |
|
|
1064 | .Ve |
|
|
1065 | .Sp |
|
|
1066 | This is more efficient then stopping/starting the timer eahc time you want |
|
|
1067 | to modify its timeout value. |
|
|
1068 | .IP "ev_tstamp repeat [read\-write]" 4 |
|
|
1069 | .IX Item "ev_tstamp repeat [read-write]" |
|
|
1070 | The current \f(CW\*(C`repeat\*(C'\fR value. Will be used each time the watcher times out |
|
|
1071 | or \f(CW\*(C`ev_timer_again\*(C'\fR is called and determines the next timeout (if any), |
|
|
1072 | which is also when any modifications are taken into account. |
|
|
1073 | .PP |
|
|
1074 | Example: Create a timer that fires after 60 seconds. |
|
|
1075 | .PP |
|
|
1076 | .Vb 5 |
|
|
1077 | \& static void |
|
|
1078 | \& one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
|
|
1079 | \& { |
|
|
1080 | \& .. one minute over, w is actually stopped right here |
|
|
1081 | \& } |
|
|
1082 | .Ve |
|
|
1083 | .PP |
|
|
1084 | .Vb 3 |
|
|
1085 | \& struct ev_timer mytimer; |
|
|
1086 | \& ev_timer_init (&mytimer, one_minute_cb, 60., 0.); |
|
|
1087 | \& ev_timer_start (loop, &mytimer); |
|
|
1088 | .Ve |
|
|
1089 | .PP |
|
|
1090 | Example: Create a timeout timer that times out after 10 seconds of |
|
|
1091 | inactivity. |
|
|
1092 | .PP |
|
|
1093 | .Vb 5 |
|
|
1094 | \& static void |
|
|
1095 | \& timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
|
|
1096 | \& { |
|
|
1097 | \& .. ten seconds without any activity |
|
|
1098 | \& } |
|
|
1099 | .Ve |
|
|
1100 | .PP |
|
|
1101 | .Vb 4 |
|
|
1102 | \& struct ev_timer mytimer; |
|
|
1103 | \& ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */ |
|
|
1104 | \& ev_timer_again (&mytimer); /* start timer */ |
|
|
1105 | \& ev_loop (loop, 0); |
|
|
1106 | .Ve |
|
|
1107 | .PP |
|
|
1108 | .Vb 3 |
|
|
1109 | \& // and in some piece of code that gets executed on any "activity": |
|
|
1110 | \& // reset the timeout to start ticking again at 10 seconds |
|
|
1111 | \& ev_timer_again (&mytimer); |
|
|
1112 | .Ve |
705 | .ie n .Sh """ev_periodic"" \- to cron or not to cron" |
1113 | .ie n .Sh """ev_periodic"" \- to cron or not to cron?" |
706 | .el .Sh "\f(CWev_periodic\fP \- to cron or not to cron" |
1114 | .el .Sh "\f(CWev_periodic\fP \- to cron or not to cron?" |
707 | .IX Subsection "ev_periodic - to cron or not to cron" |
1115 | .IX Subsection "ev_periodic - to cron or not to cron?" |
708 | Periodic watchers are also timers of a kind, but they are very versatile |
1116 | Periodic watchers are also timers of a kind, but they are very versatile |
709 | (and unfortunately a bit complex). |
1117 | (and unfortunately a bit complex). |
710 | .PP |
1118 | .PP |
711 | Unlike \f(CW\*(C`ev_timer\*(C'\fR's, they are not based on real time (or relative time) |
1119 | Unlike \f(CW\*(C`ev_timer\*(C'\fR's, they are not based on real time (or relative time) |
712 | but on wallclock time (absolute time). You can tell a periodic watcher |
1120 | but on wallclock time (absolute time). You can tell a periodic watcher |
713 | to trigger \*(L"at\*(R" some specific point in time. For example, if you tell a |
1121 | to trigger \*(L"at\*(R" some specific point in time. For example, if you tell a |
714 | periodic watcher to trigger in 10 seconds (by specifiying e.g. c<ev_now () |
1122 | periodic watcher to trigger in 10 seconds (by specifiying e.g. \f(CW\*(C`ev_now () |
715 | + 10.>) and then reset your system clock to the last year, then it will |
1123 | + 10.\*(C'\fR) and then reset your system clock to the last year, then it will |
716 | take a year to trigger the event (unlike an \f(CW\*(C`ev_timer\*(C'\fR, which would trigger |
1124 | take a year to trigger the event (unlike an \f(CW\*(C`ev_timer\*(C'\fR, which would trigger |
717 | roughly 10 seconds later and of course not if you reset your system time |
1125 | roughly 10 seconds later and of course not if you reset your system time |
718 | again). |
1126 | again). |
719 | .PP |
1127 | .PP |
720 | They can also be used to implement vastly more complex timers, such as |
1128 | They can also be used to implement vastly more complex timers, such as |
… | |
… | |
801 | .IX Item "ev_periodic_again (loop, ev_periodic *)" |
1209 | .IX Item "ev_periodic_again (loop, ev_periodic *)" |
802 | Simply stops and restarts the periodic watcher again. This is only useful |
1210 | Simply stops and restarts the periodic watcher again. This is only useful |
803 | when you changed some parameters or the reschedule callback would return |
1211 | when you changed some parameters or the reschedule callback would return |
804 | a different time than the last time it was called (e.g. in a crond like |
1212 | a different time than the last time it was called (e.g. in a crond like |
805 | program when the crontabs have changed). |
1213 | program when the crontabs have changed). |
|
|
1214 | .IP "ev_tstamp interval [read\-write]" 4 |
|
|
1215 | .IX Item "ev_tstamp interval [read-write]" |
|
|
1216 | The current interval value. Can be modified any time, but changes only |
|
|
1217 | take effect when the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being |
|
|
1218 | called. |
|
|
1219 | .IP "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read\-write]" 4 |
|
|
1220 | .IX Item "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write]" |
|
|
1221 | The current reschedule callback, or \f(CW0\fR, if this functionality is |
|
|
1222 | switched off. Can be changed any time, but changes only take effect when |
|
|
1223 | the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called. |
|
|
1224 | .PP |
|
|
1225 | Example: Call a callback every hour, or, more precisely, whenever the |
|
|
1226 | system clock is divisible by 3600. The callback invocation times have |
|
|
1227 | potentially a lot of jittering, but good long-term stability. |
|
|
1228 | .PP |
|
|
1229 | .Vb 5 |
|
|
1230 | \& static void |
|
|
1231 | \& clock_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
|
|
1232 | \& { |
|
|
1233 | \& ... its now a full hour (UTC, or TAI or whatever your clock follows) |
|
|
1234 | \& } |
|
|
1235 | .Ve |
|
|
1236 | .PP |
|
|
1237 | .Vb 3 |
|
|
1238 | \& struct ev_periodic hourly_tick; |
|
|
1239 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); |
|
|
1240 | \& ev_periodic_start (loop, &hourly_tick); |
|
|
1241 | .Ve |
|
|
1242 | .PP |
|
|
1243 | Example: The same as above, but use a reschedule callback to do it: |
|
|
1244 | .PP |
|
|
1245 | .Vb 1 |
|
|
1246 | \& #include <math.h> |
|
|
1247 | .Ve |
|
|
1248 | .PP |
|
|
1249 | .Vb 5 |
|
|
1250 | \& static ev_tstamp |
|
|
1251 | \& my_scheduler_cb (struct ev_periodic *w, ev_tstamp now) |
|
|
1252 | \& { |
|
|
1253 | \& return fmod (now, 3600.) + 3600.; |
|
|
1254 | \& } |
|
|
1255 | .Ve |
|
|
1256 | .PP |
|
|
1257 | .Vb 1 |
|
|
1258 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); |
|
|
1259 | .Ve |
|
|
1260 | .PP |
|
|
1261 | Example: Call a callback every hour, starting now: |
|
|
1262 | .PP |
|
|
1263 | .Vb 4 |
|
|
1264 | \& struct ev_periodic hourly_tick; |
|
|
1265 | \& ev_periodic_init (&hourly_tick, clock_cb, |
|
|
1266 | \& fmod (ev_now (loop), 3600.), 3600., 0); |
|
|
1267 | \& ev_periodic_start (loop, &hourly_tick); |
|
|
1268 | .Ve |
806 | .ie n .Sh """ev_signal"" \- signal me when a signal gets signalled" |
1269 | .ie n .Sh """ev_signal"" \- signal me when a signal gets signalled!" |
807 | .el .Sh "\f(CWev_signal\fP \- signal me when a signal gets signalled" |
1270 | .el .Sh "\f(CWev_signal\fP \- signal me when a signal gets signalled!" |
808 | .IX Subsection "ev_signal - signal me when a signal gets signalled" |
1271 | .IX Subsection "ev_signal - signal me when a signal gets signalled!" |
809 | Signal watchers will trigger an event when the process receives a specific |
1272 | Signal watchers will trigger an event when the process receives a specific |
810 | signal one or more times. Even though signals are very asynchronous, libev |
1273 | signal one or more times. Even though signals are very asynchronous, libev |
811 | will try it's best to deliver signals synchronously, i.e. as part of the |
1274 | will try it's best to deliver signals synchronously, i.e. as part of the |
812 | normal event processing, like any other event. |
1275 | normal event processing, like any other event. |
813 | .PP |
1276 | .PP |
… | |
… | |
823 | .IP "ev_signal_set (ev_signal *, int signum)" 4 |
1286 | .IP "ev_signal_set (ev_signal *, int signum)" 4 |
824 | .IX Item "ev_signal_set (ev_signal *, int signum)" |
1287 | .IX Item "ev_signal_set (ev_signal *, int signum)" |
825 | .PD |
1288 | .PD |
826 | Configures the watcher to trigger on the given signal number (usually one |
1289 | Configures the watcher to trigger on the given signal number (usually one |
827 | of the \f(CW\*(C`SIGxxx\*(C'\fR constants). |
1290 | of the \f(CW\*(C`SIGxxx\*(C'\fR constants). |
|
|
1291 | .IP "int signum [read\-only]" 4 |
|
|
1292 | .IX Item "int signum [read-only]" |
|
|
1293 | The signal the watcher watches out for. |
828 | .ie n .Sh """ev_child"" \- wait for pid status changes" |
1294 | .ie n .Sh """ev_child"" \- watch out for process status changes" |
829 | .el .Sh "\f(CWev_child\fP \- wait for pid status changes" |
1295 | .el .Sh "\f(CWev_child\fP \- watch out for process status changes" |
830 | .IX Subsection "ev_child - wait for pid status changes" |
1296 | .IX Subsection "ev_child - watch out for process status changes" |
831 | Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to |
1297 | Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to |
832 | some child status changes (most typically when a child of yours dies). |
1298 | some child status changes (most typically when a child of yours dies). |
833 | .IP "ev_child_init (ev_child *, callback, int pid)" 4 |
1299 | .IP "ev_child_init (ev_child *, callback, int pid)" 4 |
834 | .IX Item "ev_child_init (ev_child *, callback, int pid)" |
1300 | .IX Item "ev_child_init (ev_child *, callback, int pid)" |
835 | .PD 0 |
1301 | .PD 0 |
… | |
… | |
840 | \&\fIany\fR process if \f(CW\*(C`pid\*(C'\fR is specified as \f(CW0\fR). The callback can look |
1306 | \&\fIany\fR process if \f(CW\*(C`pid\*(C'\fR is specified as \f(CW0\fR). The callback can look |
841 | at the \f(CW\*(C`rstatus\*(C'\fR member of the \f(CW\*(C`ev_child\*(C'\fR watcher structure to see |
1307 | at the \f(CW\*(C`rstatus\*(C'\fR member of the \f(CW\*(C`ev_child\*(C'\fR watcher structure to see |
842 | the status word (use the macros from \f(CW\*(C`sys/wait.h\*(C'\fR and see your systems |
1308 | the status word (use the macros from \f(CW\*(C`sys/wait.h\*(C'\fR and see your systems |
843 | \&\f(CW\*(C`waitpid\*(C'\fR documentation). The \f(CW\*(C`rpid\*(C'\fR member contains the pid of the |
1309 | \&\f(CW\*(C`waitpid\*(C'\fR documentation). The \f(CW\*(C`rpid\*(C'\fR member contains the pid of the |
844 | process causing the status change. |
1310 | process causing the status change. |
|
|
1311 | .IP "int pid [read\-only]" 4 |
|
|
1312 | .IX Item "int pid [read-only]" |
|
|
1313 | The process id this watcher watches out for, or \f(CW0\fR, meaning any process id. |
|
|
1314 | .IP "int rpid [read\-write]" 4 |
|
|
1315 | .IX Item "int rpid [read-write]" |
|
|
1316 | The process id that detected a status change. |
|
|
1317 | .IP "int rstatus [read\-write]" 4 |
|
|
1318 | .IX Item "int rstatus [read-write]" |
|
|
1319 | The process exit/trace status caused by \f(CW\*(C`rpid\*(C'\fR (see your systems |
|
|
1320 | \&\f(CW\*(C`waitpid\*(C'\fR and \f(CW\*(C`sys/wait.h\*(C'\fR documentation for details). |
|
|
1321 | .PP |
|
|
1322 | Example: Try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0. |
|
|
1323 | .PP |
|
|
1324 | .Vb 5 |
|
|
1325 | \& static void |
|
|
1326 | \& sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
|
|
1327 | \& { |
|
|
1328 | \& ev_unloop (loop, EVUNLOOP_ALL); |
|
|
1329 | \& } |
|
|
1330 | .Ve |
|
|
1331 | .PP |
|
|
1332 | .Vb 3 |
|
|
1333 | \& struct ev_signal signal_watcher; |
|
|
1334 | \& ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
|
|
1335 | \& ev_signal_start (loop, &sigint_cb); |
|
|
1336 | .Ve |
|
|
1337 | .ie n .Sh """ev_stat"" \- did the file attributes just change?" |
|
|
1338 | .el .Sh "\f(CWev_stat\fP \- did the file attributes just change?" |
|
|
1339 | .IX Subsection "ev_stat - did the file attributes just change?" |
|
|
1340 | This watches a filesystem path for attribute changes. That is, it calls |
|
|
1341 | \&\f(CW\*(C`stat\*(C'\fR regularly (or when the \s-1OS\s0 says it changed) and sees if it changed |
|
|
1342 | compared to the last time, invoking the callback if it did. |
|
|
1343 | .PP |
|
|
1344 | The path does not need to exist: changing from \*(L"path exists\*(R" to \*(L"path does |
|
|
1345 | not exist\*(R" is a status change like any other. The condition \*(L"path does |
|
|
1346 | not exist\*(R" is signified by the \f(CW\*(C`st_nlink\*(C'\fR field being zero (which is |
|
|
1347 | otherwise always forced to be at least one) and all the other fields of |
|
|
1348 | the stat buffer having unspecified contents. |
|
|
1349 | .PP |
|
|
1350 | Since there is no standard to do this, the portable implementation simply |
|
|
1351 | calls \f(CW\*(C`stat (2)\*(C'\fR regulalry on the path to see if it changed somehow. You |
|
|
1352 | can specify a recommended polling interval for this case. If you specify |
|
|
1353 | a polling interval of \f(CW0\fR (highly recommended!) then a \fIsuitable, |
|
|
1354 | unspecified default\fR value will be used (which you can expect to be around |
|
|
1355 | five seconds, although this might change dynamically). Libev will also |
|
|
1356 | impose a minimum interval which is currently around \f(CW0.1\fR, but thats |
|
|
1357 | usually overkill. |
|
|
1358 | .PP |
|
|
1359 | This watcher type is not meant for massive numbers of stat watchers, |
|
|
1360 | as even with OS-supported change notifications, this can be |
|
|
1361 | resource\-intensive. |
|
|
1362 | .PP |
|
|
1363 | At the time of this writing, no specific \s-1OS\s0 backends are implemented, but |
|
|
1364 | if demand increases, at least a kqueue and inotify backend will be added. |
|
|
1365 | .IP "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" 4 |
|
|
1366 | .IX Item "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" |
|
|
1367 | .PD 0 |
|
|
1368 | .IP "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" 4 |
|
|
1369 | .IX Item "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" |
|
|
1370 | .PD |
|
|
1371 | Configures the watcher to wait for status changes of the given |
|
|
1372 | \&\f(CW\*(C`path\*(C'\fR. The \f(CW\*(C`interval\*(C'\fR is a hint on how quickly a change is expected to |
|
|
1373 | be detected and should normally be specified as \f(CW0\fR to let libev choose |
|
|
1374 | a suitable value. The memory pointed to by \f(CW\*(C`path\*(C'\fR must point to the same |
|
|
1375 | path for as long as the watcher is active. |
|
|
1376 | .Sp |
|
|
1377 | The callback will be receive \f(CW\*(C`EV_STAT\*(C'\fR when a change was detected, |
|
|
1378 | relative to the attributes at the time the watcher was started (or the |
|
|
1379 | last change was detected). |
|
|
1380 | .IP "ev_stat_stat (ev_stat *)" 4 |
|
|
1381 | .IX Item "ev_stat_stat (ev_stat *)" |
|
|
1382 | Updates the stat buffer immediately with new values. If you change the |
|
|
1383 | watched path in your callback, you could call this fucntion to avoid |
|
|
1384 | detecting this change (while introducing a race condition). Can also be |
|
|
1385 | useful simply to find out the new values. |
|
|
1386 | .IP "ev_statdata attr [read\-only]" 4 |
|
|
1387 | .IX Item "ev_statdata attr [read-only]" |
|
|
1388 | The most-recently detected attributes of the file. Although the type is of |
|
|
1389 | \&\f(CW\*(C`ev_statdata\*(C'\fR, this is usually the (or one of the) \f(CW\*(C`struct stat\*(C'\fR types |
|
|
1390 | suitable for your system. If the \f(CW\*(C`st_nlink\*(C'\fR member is \f(CW0\fR, then there |
|
|
1391 | was some error while \f(CW\*(C`stat\*(C'\fRing the file. |
|
|
1392 | .IP "ev_statdata prev [read\-only]" 4 |
|
|
1393 | .IX Item "ev_statdata prev [read-only]" |
|
|
1394 | The previous attributes of the file. The callback gets invoked whenever |
|
|
1395 | \&\f(CW\*(C`prev\*(C'\fR != \f(CW\*(C`attr\*(C'\fR. |
|
|
1396 | .IP "ev_tstamp interval [read\-only]" 4 |
|
|
1397 | .IX Item "ev_tstamp interval [read-only]" |
|
|
1398 | The specified interval. |
|
|
1399 | .IP "const char *path [read\-only]" 4 |
|
|
1400 | .IX Item "const char *path [read-only]" |
|
|
1401 | The filesystem path that is being watched. |
|
|
1402 | .PP |
|
|
1403 | Example: Watch \f(CW\*(C`/etc/passwd\*(C'\fR for attribute changes. |
|
|
1404 | .PP |
|
|
1405 | .Vb 15 |
|
|
1406 | \& static void |
|
|
1407 | \& passwd_cb (struct ev_loop *loop, ev_stat *w, int revents) |
|
|
1408 | \& { |
|
|
1409 | \& /* /etc/passwd changed in some way */ |
|
|
1410 | \& if (w->attr.st_nlink) |
|
|
1411 | \& { |
|
|
1412 | \& printf ("passwd current size %ld\en", (long)w->attr.st_size); |
|
|
1413 | \& printf ("passwd current atime %ld\en", (long)w->attr.st_mtime); |
|
|
1414 | \& printf ("passwd current mtime %ld\en", (long)w->attr.st_mtime); |
|
|
1415 | \& } |
|
|
1416 | \& else |
|
|
1417 | \& /* you shalt not abuse printf for puts */ |
|
|
1418 | \& puts ("wow, /etc/passwd is not there, expect problems. " |
|
|
1419 | \& "if this is windows, they already arrived\en"); |
|
|
1420 | \& } |
|
|
1421 | .Ve |
|
|
1422 | .PP |
|
|
1423 | .Vb 2 |
|
|
1424 | \& ... |
|
|
1425 | \& ev_stat passwd; |
|
|
1426 | .Ve |
|
|
1427 | .PP |
|
|
1428 | .Vb 2 |
|
|
1429 | \& ev_stat_init (&passwd, passwd_cb, "/etc/passwd"); |
|
|
1430 | \& ev_stat_start (loop, &passwd); |
|
|
1431 | .Ve |
845 | .ie n .Sh """ev_idle"" \- when you've got nothing better to do" |
1432 | .ie n .Sh """ev_idle"" \- when you've got nothing better to do..." |
846 | .el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do" |
1433 | .el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do..." |
847 | .IX Subsection "ev_idle - when you've got nothing better to do" |
1434 | .IX Subsection "ev_idle - when you've got nothing better to do..." |
848 | Idle watchers trigger events when there are no other events are pending |
1435 | Idle watchers trigger events when there are no other events are pending |
849 | (prepare, check and other idle watchers do not count). That is, as long |
1436 | (prepare, check and other idle watchers do not count). That is, as long |
850 | as your process is busy handling sockets or timeouts (or even signals, |
1437 | as your process is busy handling sockets or timeouts (or even signals, |
851 | imagine) it will not be triggered. But when your process is idle all idle |
1438 | imagine) it will not be triggered. But when your process is idle all idle |
852 | watchers are being called again and again, once per event loop iteration \- |
1439 | watchers are being called again and again, once per event loop iteration \- |
… | |
… | |
863 | .IP "ev_idle_init (ev_signal *, callback)" 4 |
1450 | .IP "ev_idle_init (ev_signal *, callback)" 4 |
864 | .IX Item "ev_idle_init (ev_signal *, callback)" |
1451 | .IX Item "ev_idle_init (ev_signal *, callback)" |
865 | Initialises and configures the idle watcher \- it has no parameters of any |
1452 | Initialises and configures the idle watcher \- it has no parameters of any |
866 | kind. There is a \f(CW\*(C`ev_idle_set\*(C'\fR macro, but using it is utterly pointless, |
1453 | kind. There is a \f(CW\*(C`ev_idle_set\*(C'\fR macro, but using it is utterly pointless, |
867 | believe me. |
1454 | believe me. |
|
|
1455 | .PP |
|
|
1456 | Example: Dynamically allocate an \f(CW\*(C`ev_idle\*(C'\fR watcher, start it, and in the |
|
|
1457 | callback, free it. Also, use no error checking, as usual. |
|
|
1458 | .PP |
|
|
1459 | .Vb 7 |
|
|
1460 | \& static void |
|
|
1461 | \& idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
|
|
1462 | \& { |
|
|
1463 | \& free (w); |
|
|
1464 | \& // now do something you wanted to do when the program has |
|
|
1465 | \& // no longer asnything immediate to do. |
|
|
1466 | \& } |
|
|
1467 | .Ve |
|
|
1468 | .PP |
|
|
1469 | .Vb 3 |
|
|
1470 | \& struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle)); |
|
|
1471 | \& ev_idle_init (idle_watcher, idle_cb); |
|
|
1472 | \& ev_idle_start (loop, idle_cb); |
|
|
1473 | .Ve |
868 | .ie n .Sh """ev_prepare""\fP and \f(CW""ev_check"" \- customise your event loop" |
1474 | .ie n .Sh """ev_prepare""\fP and \f(CW""ev_check"" \- customise your event loop!" |
869 | .el .Sh "\f(CWev_prepare\fP and \f(CWev_check\fP \- customise your event loop" |
1475 | .el .Sh "\f(CWev_prepare\fP and \f(CWev_check\fP \- customise your event loop!" |
870 | .IX Subsection "ev_prepare and ev_check - customise your event loop" |
1476 | .IX Subsection "ev_prepare and ev_check - customise your event loop!" |
871 | Prepare and check watchers are usually (but not always) used in tandem: |
1477 | Prepare and check watchers are usually (but not always) used in tandem: |
872 | prepare watchers get invoked before the process blocks and check watchers |
1478 | prepare watchers get invoked before the process blocks and check watchers |
873 | afterwards. |
1479 | afterwards. |
874 | .PP |
1480 | .PP |
|
|
1481 | You \fImust not\fR call \f(CW\*(C`ev_loop\*(C'\fR or similar functions that enter |
|
|
1482 | the current event loop from either \f(CW\*(C`ev_prepare\*(C'\fR or \f(CW\*(C`ev_check\*(C'\fR |
|
|
1483 | watchers. Other loops than the current one are fine, however. The |
|
|
1484 | rationale behind this is that you do not need to check for recursion in |
|
|
1485 | those watchers, i.e. the sequence will always be \f(CW\*(C`ev_prepare\*(C'\fR, blocking, |
|
|
1486 | \&\f(CW\*(C`ev_check\*(C'\fR so if you have one watcher of each kind they will always be |
|
|
1487 | called in pairs bracketing the blocking call. |
|
|
1488 | .PP |
875 | Their main purpose is to integrate other event mechanisms into libev. This |
1489 | Their main purpose is to integrate other event mechanisms into libev and |
876 | could be used, for example, to track variable changes, implement your own |
1490 | their use is somewhat advanced. This could be used, for example, to track |
877 | watchers, integrate net-snmp or a coroutine library and lots more. |
1491 | variable changes, implement your own watchers, integrate net-snmp or a |
|
|
1492 | coroutine library and lots more. They are also occasionally useful if |
|
|
1493 | you cache some data and want to flush it before blocking (for example, |
|
|
1494 | in X programs you might want to do an \f(CW\*(C`XFlush ()\*(C'\fR in an \f(CW\*(C`ev_prepare\*(C'\fR |
|
|
1495 | watcher). |
878 | .PP |
1496 | .PP |
879 | This is done by examining in each prepare call which file descriptors need |
1497 | This is done by examining in each prepare call which file descriptors need |
880 | to be watched by the other library, registering \f(CW\*(C`ev_io\*(C'\fR watchers for |
1498 | to be watched by the other library, registering \f(CW\*(C`ev_io\*(C'\fR watchers for |
881 | them and starting an \f(CW\*(C`ev_timer\*(C'\fR watcher for any timeouts (many libraries |
1499 | them and starting an \f(CW\*(C`ev_timer\*(C'\fR watcher for any timeouts (many libraries |
882 | provide just this functionality). Then, in the check watcher you check for |
1500 | provide just this functionality). Then, in the check watcher you check for |
… | |
… | |
900 | .IX Item "ev_check_init (ev_check *, callback)" |
1518 | .IX Item "ev_check_init (ev_check *, callback)" |
901 | .PD |
1519 | .PD |
902 | Initialises and configures the prepare or check watcher \- they have no |
1520 | Initialises and configures the prepare or check watcher \- they have no |
903 | parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR |
1521 | parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR |
904 | macros, but using them is utterly, utterly and completely pointless. |
1522 | macros, but using them is utterly, utterly and completely pointless. |
|
|
1523 | .PP |
|
|
1524 | Example: To include a library such as adns, you would add \s-1IO\s0 watchers |
|
|
1525 | and a timeout watcher in a prepare handler, as required by libadns, and |
|
|
1526 | in a check watcher, destroy them and call into libadns. What follows is |
|
|
1527 | pseudo-code only of course: |
|
|
1528 | .PP |
|
|
1529 | .Vb 2 |
|
|
1530 | \& static ev_io iow [nfd]; |
|
|
1531 | \& static ev_timer tw; |
|
|
1532 | .Ve |
|
|
1533 | .PP |
|
|
1534 | .Vb 9 |
|
|
1535 | \& static void |
|
|
1536 | \& io_cb (ev_loop *loop, ev_io *w, int revents) |
|
|
1537 | \& { |
|
|
1538 | \& // set the relevant poll flags |
|
|
1539 | \& // could also call adns_processreadable etc. here |
|
|
1540 | \& struct pollfd *fd = (struct pollfd *)w->data; |
|
|
1541 | \& if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
|
|
1542 | \& if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
|
|
1543 | \& } |
|
|
1544 | .Ve |
|
|
1545 | .PP |
|
|
1546 | .Vb 7 |
|
|
1547 | \& // create io watchers for each fd and a timer before blocking |
|
|
1548 | \& static void |
|
|
1549 | \& adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
|
|
1550 | \& { |
|
|
1551 | \& int timeout = 3600000;truct pollfd fds [nfd]; |
|
|
1552 | \& // actual code will need to loop here and realloc etc. |
|
|
1553 | \& adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
|
|
1554 | .Ve |
|
|
1555 | .PP |
|
|
1556 | .Vb 3 |
|
|
1557 | \& /* the callback is illegal, but won't be called as we stop during check */ |
|
|
1558 | \& ev_timer_init (&tw, 0, timeout * 1e-3); |
|
|
1559 | \& ev_timer_start (loop, &tw); |
|
|
1560 | .Ve |
|
|
1561 | .PP |
|
|
1562 | .Vb 6 |
|
|
1563 | \& // create on ev_io per pollfd |
|
|
1564 | \& for (int i = 0; i < nfd; ++i) |
|
|
1565 | \& { |
|
|
1566 | \& ev_io_init (iow + i, io_cb, fds [i].fd, |
|
|
1567 | \& ((fds [i].events & POLLIN ? EV_READ : 0) |
|
|
1568 | \& | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
|
|
1569 | .Ve |
|
|
1570 | .PP |
|
|
1571 | .Vb 5 |
|
|
1572 | \& fds [i].revents = 0; |
|
|
1573 | \& iow [i].data = fds + i; |
|
|
1574 | \& ev_io_start (loop, iow + i); |
|
|
1575 | \& } |
|
|
1576 | \& } |
|
|
1577 | .Ve |
|
|
1578 | .PP |
|
|
1579 | .Vb 5 |
|
|
1580 | \& // stop all watchers after blocking |
|
|
1581 | \& static void |
|
|
1582 | \& adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
|
|
1583 | \& { |
|
|
1584 | \& ev_timer_stop (loop, &tw); |
|
|
1585 | .Ve |
|
|
1586 | .PP |
|
|
1587 | .Vb 2 |
|
|
1588 | \& for (int i = 0; i < nfd; ++i) |
|
|
1589 | \& ev_io_stop (loop, iow + i); |
|
|
1590 | .Ve |
|
|
1591 | .PP |
|
|
1592 | .Vb 2 |
|
|
1593 | \& adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
|
|
1594 | \& } |
|
|
1595 | .Ve |
|
|
1596 | .ie n .Sh """ev_embed"" \- when one backend isn't enough..." |
|
|
1597 | .el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..." |
|
|
1598 | .IX Subsection "ev_embed - when one backend isn't enough..." |
|
|
1599 | This is a rather advanced watcher type that lets you embed one event loop |
|
|
1600 | into another (currently only \f(CW\*(C`ev_io\*(C'\fR events are supported in the embedded |
|
|
1601 | loop, other types of watchers might be handled in a delayed or incorrect |
|
|
1602 | fashion and must not be used). |
|
|
1603 | .PP |
|
|
1604 | There are primarily two reasons you would want that: work around bugs and |
|
|
1605 | prioritise I/O. |
|
|
1606 | .PP |
|
|
1607 | As an example for a bug workaround, the kqueue backend might only support |
|
|
1608 | sockets on some platform, so it is unusable as generic backend, but you |
|
|
1609 | still want to make use of it because you have many sockets and it scales |
|
|
1610 | so nicely. In this case, you would create a kqueue-based loop and embed it |
|
|
1611 | into your default loop (which might use e.g. poll). Overall operation will |
|
|
1612 | be a bit slower because first libev has to poll and then call kevent, but |
|
|
1613 | at least you can use both at what they are best. |
|
|
1614 | .PP |
|
|
1615 | As for prioritising I/O: rarely you have the case where some fds have |
|
|
1616 | to be watched and handled very quickly (with low latency), and even |
|
|
1617 | priorities and idle watchers might have too much overhead. In this case |
|
|
1618 | you would put all the high priority stuff in one loop and all the rest in |
|
|
1619 | a second one, and embed the second one in the first. |
|
|
1620 | .PP |
|
|
1621 | As long as the watcher is active, the callback will be invoked every time |
|
|
1622 | there might be events pending in the embedded loop. The callback must then |
|
|
1623 | call \f(CW\*(C`ev_embed_sweep (mainloop, watcher)\*(C'\fR to make a single sweep and invoke |
|
|
1624 | their callbacks (you could also start an idle watcher to give the embedded |
|
|
1625 | loop strictly lower priority for example). You can also set the callback |
|
|
1626 | to \f(CW0\fR, in which case the embed watcher will automatically execute the |
|
|
1627 | embedded loop sweep. |
|
|
1628 | .PP |
|
|
1629 | As long as the watcher is started it will automatically handle events. The |
|
|
1630 | callback will be invoked whenever some events have been handled. You can |
|
|
1631 | set the callback to \f(CW0\fR to avoid having to specify one if you are not |
|
|
1632 | interested in that. |
|
|
1633 | .PP |
|
|
1634 | Also, there have not currently been made special provisions for forking: |
|
|
1635 | when you fork, you not only have to call \f(CW\*(C`ev_loop_fork\*(C'\fR on both loops, |
|
|
1636 | but you will also have to stop and restart any \f(CW\*(C`ev_embed\*(C'\fR watchers |
|
|
1637 | yourself. |
|
|
1638 | .PP |
|
|
1639 | Unfortunately, not all backends are embeddable, only the ones returned by |
|
|
1640 | \&\f(CW\*(C`ev_embeddable_backends\*(C'\fR are, which, unfortunately, does not include any |
|
|
1641 | portable one. |
|
|
1642 | .PP |
|
|
1643 | So when you want to use this feature you will always have to be prepared |
|
|
1644 | that you cannot get an embeddable loop. The recommended way to get around |
|
|
1645 | this is to have a separate variables for your embeddable loop, try to |
|
|
1646 | create it, and if that fails, use the normal loop for everything: |
|
|
1647 | .PP |
|
|
1648 | .Vb 3 |
|
|
1649 | \& struct ev_loop *loop_hi = ev_default_init (0); |
|
|
1650 | \& struct ev_loop *loop_lo = 0; |
|
|
1651 | \& struct ev_embed embed; |
|
|
1652 | .Ve |
|
|
1653 | .PP |
|
|
1654 | .Vb 5 |
|
|
1655 | \& // see if there is a chance of getting one that works |
|
|
1656 | \& // (remember that a flags value of 0 means autodetection) |
|
|
1657 | \& loop_lo = ev_embeddable_backends () & ev_recommended_backends () |
|
|
1658 | \& ? ev_loop_new (ev_embeddable_backends () & ev_recommended_backends ()) |
|
|
1659 | \& : 0; |
|
|
1660 | .Ve |
|
|
1661 | .PP |
|
|
1662 | .Vb 8 |
|
|
1663 | \& // if we got one, then embed it, otherwise default to loop_hi |
|
|
1664 | \& if (loop_lo) |
|
|
1665 | \& { |
|
|
1666 | \& ev_embed_init (&embed, 0, loop_lo); |
|
|
1667 | \& ev_embed_start (loop_hi, &embed); |
|
|
1668 | \& } |
|
|
1669 | \& else |
|
|
1670 | \& loop_lo = loop_hi; |
|
|
1671 | .Ve |
|
|
1672 | .IP "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
|
|
1673 | .IX Item "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" |
|
|
1674 | .PD 0 |
|
|
1675 | .IP "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
|
|
1676 | .IX Item "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" |
|
|
1677 | .PD |
|
|
1678 | Configures the watcher to embed the given loop, which must be |
|
|
1679 | embeddable. If the callback is \f(CW0\fR, then \f(CW\*(C`ev_embed_sweep\*(C'\fR will be |
|
|
1680 | invoked automatically, otherwise it is the responsibility of the callback |
|
|
1681 | to invoke it (it will continue to be called until the sweep has been done, |
|
|
1682 | if you do not want thta, you need to temporarily stop the embed watcher). |
|
|
1683 | .IP "ev_embed_sweep (loop, ev_embed *)" 4 |
|
|
1684 | .IX Item "ev_embed_sweep (loop, ev_embed *)" |
|
|
1685 | Make a single, non-blocking sweep over the embedded loop. This works |
|
|
1686 | similarly to \f(CW\*(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\*(C'\fR, but in the most |
|
|
1687 | apropriate way for embedded loops. |
|
|
1688 | .IP "struct ev_loop *loop [read\-only]" 4 |
|
|
1689 | .IX Item "struct ev_loop *loop [read-only]" |
|
|
1690 | The embedded event loop. |
|
|
1691 | .ie n .Sh """ev_fork"" \- the audacity to resume the event loop after a fork" |
|
|
1692 | .el .Sh "\f(CWev_fork\fP \- the audacity to resume the event loop after a fork" |
|
|
1693 | .IX Subsection "ev_fork - the audacity to resume the event loop after a fork" |
|
|
1694 | Fork watchers are called when a \f(CW\*(C`fork ()\*(C'\fR was detected (usually because |
|
|
1695 | whoever is a good citizen cared to tell libev about it by calling |
|
|
1696 | \&\f(CW\*(C`ev_default_fork\*(C'\fR or \f(CW\*(C`ev_loop_fork\*(C'\fR). The invocation is done before the |
|
|
1697 | event loop blocks next and before \f(CW\*(C`ev_check\*(C'\fR watchers are being called, |
|
|
1698 | and only in the child after the fork. If whoever good citizen calling |
|
|
1699 | \&\f(CW\*(C`ev_default_fork\*(C'\fR cheats and calls it in the wrong process, the fork |
|
|
1700 | handlers will be invoked, too, of course. |
|
|
1701 | .IP "ev_fork_init (ev_signal *, callback)" 4 |
|
|
1702 | .IX Item "ev_fork_init (ev_signal *, callback)" |
|
|
1703 | Initialises and configures the fork watcher \- it has no parameters of any |
|
|
1704 | kind. There is a \f(CW\*(C`ev_fork_set\*(C'\fR macro, but using it is utterly pointless, |
|
|
1705 | believe me. |
905 | .SH "OTHER FUNCTIONS" |
1706 | .SH "OTHER FUNCTIONS" |
906 | .IX Header "OTHER FUNCTIONS" |
1707 | .IX Header "OTHER FUNCTIONS" |
907 | There are some other functions of possible interest. Described. Here. Now. |
1708 | There are some other functions of possible interest. Described. Here. Now. |
908 | .IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4 |
1709 | .IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4 |
909 | .IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" |
1710 | .IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" |
… | |
… | |
938 | .Ve |
1739 | .Ve |
939 | .Sp |
1740 | .Sp |
940 | .Vb 1 |
1741 | .Vb 1 |
941 | \& ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0); |
1742 | \& ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0); |
942 | .Ve |
1743 | .Ve |
943 | .IP "ev_feed_event (loop, watcher, int events)" 4 |
1744 | .IP "ev_feed_event (ev_loop *, watcher *, int revents)" 4 |
944 | .IX Item "ev_feed_event (loop, watcher, int events)" |
1745 | .IX Item "ev_feed_event (ev_loop *, watcher *, int revents)" |
945 | Feeds the given event set into the event loop, as if the specified event |
1746 | Feeds the given event set into the event loop, as if the specified event |
946 | had happened for the specified watcher (which must be a pointer to an |
1747 | had happened for the specified watcher (which must be a pointer to an |
947 | initialised but not necessarily started event watcher). |
1748 | initialised but not necessarily started event watcher). |
948 | .IP "ev_feed_fd_event (loop, int fd, int revents)" 4 |
1749 | .IP "ev_feed_fd_event (ev_loop *, int fd, int revents)" 4 |
949 | .IX Item "ev_feed_fd_event (loop, int fd, int revents)" |
1750 | .IX Item "ev_feed_fd_event (ev_loop *, int fd, int revents)" |
950 | Feed an event on the given fd, as if a file descriptor backend detected |
1751 | Feed an event on the given fd, as if a file descriptor backend detected |
951 | the given events it. |
1752 | the given events it. |
952 | .IP "ev_feed_signal_event (loop, int signum)" 4 |
1753 | .IP "ev_feed_signal_event (ev_loop *loop, int signum)" 4 |
953 | .IX Item "ev_feed_signal_event (loop, int signum)" |
1754 | .IX Item "ev_feed_signal_event (ev_loop *loop, int signum)" |
954 | Feed an event as if the given signal occured (loop must be the default loop!). |
1755 | Feed an event as if the given signal occured (\f(CW\*(C`loop\*(C'\fR must be the default |
|
|
1756 | loop!). |
955 | .SH "LIBEVENT EMULATION" |
1757 | .SH "LIBEVENT EMULATION" |
956 | .IX Header "LIBEVENT EMULATION" |
1758 | .IX Header "LIBEVENT EMULATION" |
957 | Libev offers a compatibility emulation layer for libevent. It cannot |
1759 | Libev offers a compatibility emulation layer for libevent. It cannot |
958 | emulate the internals of libevent, so here are some usage hints: |
1760 | emulate the internals of libevent, so here are some usage hints: |
959 | .IP "* Use it by including <event.h>, as usual." 4 |
1761 | .IP "* Use it by including <event.h>, as usual." 4 |
… | |
… | |
970 | .IP "* The libev emulation is \fInot\fR \s-1ABI\s0 compatible to libevent, you need to use the libev header file and library." 4 |
1772 | .IP "* The libev emulation is \fInot\fR \s-1ABI\s0 compatible to libevent, you need to use the libev header file and library." 4 |
971 | .IX Item "The libev emulation is not ABI compatible to libevent, you need to use the libev header file and library." |
1773 | .IX Item "The libev emulation is not ABI compatible to libevent, you need to use the libev header file and library." |
972 | .PD |
1774 | .PD |
973 | .SH "\*(C+ SUPPORT" |
1775 | .SH "\*(C+ SUPPORT" |
974 | .IX Header " SUPPORT" |
1776 | .IX Header " SUPPORT" |
975 | \&\s-1TBD\s0. |
1777 | Libev comes with some simplistic wrapper classes for \*(C+ that mainly allow |
|
|
1778 | you to use some convinience methods to start/stop watchers and also change |
|
|
1779 | the callback model to a model using method callbacks on objects. |
|
|
1780 | .PP |
|
|
1781 | To use it, |
|
|
1782 | .PP |
|
|
1783 | .Vb 1 |
|
|
1784 | \& #include <ev++.h> |
|
|
1785 | .Ve |
|
|
1786 | .PP |
|
|
1787 | (it is not installed by default). This automatically includes \fIev.h\fR |
|
|
1788 | and puts all of its definitions (many of them macros) into the global |
|
|
1789 | namespace. All \*(C+ specific things are put into the \f(CW\*(C`ev\*(C'\fR namespace. |
|
|
1790 | .PP |
|
|
1791 | It should support all the same embedding options as \fIev.h\fR, most notably |
|
|
1792 | \&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. |
|
|
1793 | .PP |
|
|
1794 | Here is a list of things available in the \f(CW\*(C`ev\*(C'\fR namespace: |
|
|
1795 | .ie n .IP """ev::READ""\fR, \f(CW""ev::WRITE"" etc." 4 |
|
|
1796 | .el .IP "\f(CWev::READ\fR, \f(CWev::WRITE\fR etc." 4 |
|
|
1797 | .IX Item "ev::READ, ev::WRITE etc." |
|
|
1798 | These are just enum values with the same values as the \f(CW\*(C`EV_READ\*(C'\fR etc. |
|
|
1799 | macros from \fIev.h\fR. |
|
|
1800 | .ie n .IP """ev::tstamp""\fR, \f(CW""ev::now""" 4 |
|
|
1801 | .el .IP "\f(CWev::tstamp\fR, \f(CWev::now\fR" 4 |
|
|
1802 | .IX Item "ev::tstamp, ev::now" |
|
|
1803 | Aliases to the same types/functions as with the \f(CW\*(C`ev_\*(C'\fR prefix. |
|
|
1804 | .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 |
|
|
1805 | .el .IP "\f(CWev::io\fR, \f(CWev::timer\fR, \f(CWev::periodic\fR, \f(CWev::idle\fR, \f(CWev::sig\fR etc." 4 |
|
|
1806 | .IX Item "ev::io, ev::timer, ev::periodic, ev::idle, ev::sig etc." |
|
|
1807 | For each \f(CW\*(C`ev_TYPE\*(C'\fR watcher in \fIev.h\fR there is a corresponding class of |
|
|
1808 | the same name in the \f(CW\*(C`ev\*(C'\fR namespace, with the exception of \f(CW\*(C`ev_signal\*(C'\fR |
|
|
1809 | which is called \f(CW\*(C`ev::sig\*(C'\fR to avoid clashes with the \f(CW\*(C`signal\*(C'\fR macro |
|
|
1810 | defines by many implementations. |
|
|
1811 | .Sp |
|
|
1812 | All of those classes have these methods: |
|
|
1813 | .RS 4 |
|
|
1814 | .IP "ev::TYPE::TYPE (object *, object::method *)" 4 |
|
|
1815 | .IX Item "ev::TYPE::TYPE (object *, object::method *)" |
|
|
1816 | .PD 0 |
|
|
1817 | .IP "ev::TYPE::TYPE (object *, object::method *, struct ev_loop *)" 4 |
|
|
1818 | .IX Item "ev::TYPE::TYPE (object *, object::method *, struct ev_loop *)" |
|
|
1819 | .IP "ev::TYPE::~TYPE" 4 |
|
|
1820 | .IX Item "ev::TYPE::~TYPE" |
|
|
1821 | .PD |
|
|
1822 | The constructor takes a pointer to an object and a method pointer to |
|
|
1823 | the event handler callback to call in this class. The constructor calls |
|
|
1824 | \&\f(CW\*(C`ev_init\*(C'\fR for you, which means you have to call the \f(CW\*(C`set\*(C'\fR method |
|
|
1825 | before starting it. If you do not specify a loop then the constructor |
|
|
1826 | automatically associates the default loop with this watcher. |
|
|
1827 | .Sp |
|
|
1828 | The destructor automatically stops the watcher if it is active. |
|
|
1829 | .IP "w\->set (struct ev_loop *)" 4 |
|
|
1830 | .IX Item "w->set (struct ev_loop *)" |
|
|
1831 | Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only |
|
|
1832 | do this when the watcher is inactive (and not pending either). |
|
|
1833 | .IP "w\->set ([args])" 4 |
|
|
1834 | .IX Item "w->set ([args])" |
|
|
1835 | Basically the same as \f(CW\*(C`ev_TYPE_set\*(C'\fR, with the same args. Must be |
|
|
1836 | called at least once. Unlike the C counterpart, an active watcher gets |
|
|
1837 | automatically stopped and restarted. |
|
|
1838 | .IP "w\->start ()" 4 |
|
|
1839 | .IX Item "w->start ()" |
|
|
1840 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument as the |
|
|
1841 | constructor already takes the loop. |
|
|
1842 | .IP "w\->stop ()" 4 |
|
|
1843 | .IX Item "w->stop ()" |
|
|
1844 | Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument. |
|
|
1845 | .ie n .IP "w\->again () ""ev::timer""\fR, \f(CW""ev::periodic"" only" 4 |
|
|
1846 | .el .IP "w\->again () \f(CWev::timer\fR, \f(CWev::periodic\fR only" 4 |
|
|
1847 | .IX Item "w->again () ev::timer, ev::periodic only" |
|
|
1848 | For \f(CW\*(C`ev::timer\*(C'\fR and \f(CW\*(C`ev::periodic\*(C'\fR, this invokes the corresponding |
|
|
1849 | \&\f(CW\*(C`ev_TYPE_again\*(C'\fR function. |
|
|
1850 | .ie n .IP "w\->sweep () ""ev::embed"" only" 4 |
|
|
1851 | .el .IP "w\->sweep () \f(CWev::embed\fR only" 4 |
|
|
1852 | .IX Item "w->sweep () ev::embed only" |
|
|
1853 | Invokes \f(CW\*(C`ev_embed_sweep\*(C'\fR. |
|
|
1854 | .ie n .IP "w\->update () ""ev::stat"" only" 4 |
|
|
1855 | .el .IP "w\->update () \f(CWev::stat\fR only" 4 |
|
|
1856 | .IX Item "w->update () ev::stat only" |
|
|
1857 | Invokes \f(CW\*(C`ev_stat_stat\*(C'\fR. |
|
|
1858 | .RE |
|
|
1859 | .RS 4 |
|
|
1860 | .RE |
|
|
1861 | .PP |
|
|
1862 | Example: Define a class with an \s-1IO\s0 and idle watcher, start one of them in |
|
|
1863 | the constructor. |
|
|
1864 | .PP |
|
|
1865 | .Vb 4 |
|
|
1866 | \& class myclass |
|
|
1867 | \& { |
|
|
1868 | \& ev_io io; void io_cb (ev::io &w, int revents); |
|
|
1869 | \& ev_idle idle void idle_cb (ev::idle &w, int revents); |
|
|
1870 | .Ve |
|
|
1871 | .PP |
|
|
1872 | .Vb 2 |
|
|
1873 | \& myclass (); |
|
|
1874 | \& } |
|
|
1875 | .Ve |
|
|
1876 | .PP |
|
|
1877 | .Vb 6 |
|
|
1878 | \& myclass::myclass (int fd) |
|
|
1879 | \& : io (this, &myclass::io_cb), |
|
|
1880 | \& idle (this, &myclass::idle_cb) |
|
|
1881 | \& { |
|
|
1882 | \& io.start (fd, ev::READ); |
|
|
1883 | \& } |
|
|
1884 | .Ve |
|
|
1885 | .SH "MACRO MAGIC" |
|
|
1886 | .IX Header "MACRO MAGIC" |
|
|
1887 | Libev can be compiled with a variety of options, the most fundemantal is |
|
|
1888 | \&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines wether (most) functions and |
|
|
1889 | callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument. |
|
|
1890 | .PP |
|
|
1891 | To make it easier to write programs that cope with either variant, the |
|
|
1892 | following macros are defined: |
|
|
1893 | .ie n .IP """EV_A""\fR, \f(CW""EV_A_""" 4 |
|
|
1894 | .el .IP "\f(CWEV_A\fR, \f(CWEV_A_\fR" 4 |
|
|
1895 | .IX Item "EV_A, EV_A_" |
|
|
1896 | This provides the loop \fIargument\fR for functions, if one is required (\*(L"ev |
|
|
1897 | loop argument\*(R"). The \f(CW\*(C`EV_A\*(C'\fR form is used when this is the sole argument, |
|
|
1898 | \&\f(CW\*(C`EV_A_\*(C'\fR is used when other arguments are following. Example: |
|
|
1899 | .Sp |
|
|
1900 | .Vb 3 |
|
|
1901 | \& ev_unref (EV_A); |
|
|
1902 | \& ev_timer_add (EV_A_ watcher); |
|
|
1903 | \& ev_loop (EV_A_ 0); |
|
|
1904 | .Ve |
|
|
1905 | .Sp |
|
|
1906 | It assumes the variable \f(CW\*(C`loop\*(C'\fR of type \f(CW\*(C`struct ev_loop *\*(C'\fR is in scope, |
|
|
1907 | which is often provided by the following macro. |
|
|
1908 | .ie n .IP """EV_P""\fR, \f(CW""EV_P_""" 4 |
|
|
1909 | .el .IP "\f(CWEV_P\fR, \f(CWEV_P_\fR" 4 |
|
|
1910 | .IX Item "EV_P, EV_P_" |
|
|
1911 | This provides the loop \fIparameter\fR for functions, if one is required (\*(L"ev |
|
|
1912 | loop parameter\*(R"). The \f(CW\*(C`EV_P\*(C'\fR form is used when this is the sole parameter, |
|
|
1913 | \&\f(CW\*(C`EV_P_\*(C'\fR is used when other parameters are following. Example: |
|
|
1914 | .Sp |
|
|
1915 | .Vb 2 |
|
|
1916 | \& // this is how ev_unref is being declared |
|
|
1917 | \& static void ev_unref (EV_P); |
|
|
1918 | .Ve |
|
|
1919 | .Sp |
|
|
1920 | .Vb 2 |
|
|
1921 | \& // this is how you can declare your typical callback |
|
|
1922 | \& static void cb (EV_P_ ev_timer *w, int revents) |
|
|
1923 | .Ve |
|
|
1924 | .Sp |
|
|
1925 | It declares a parameter \f(CW\*(C`loop\*(C'\fR of type \f(CW\*(C`struct ev_loop *\*(C'\fR, quite |
|
|
1926 | suitable for use with \f(CW\*(C`EV_A\*(C'\fR. |
|
|
1927 | .ie n .IP """EV_DEFAULT""\fR, \f(CW""EV_DEFAULT_""" 4 |
|
|
1928 | .el .IP "\f(CWEV_DEFAULT\fR, \f(CWEV_DEFAULT_\fR" 4 |
|
|
1929 | .IX Item "EV_DEFAULT, EV_DEFAULT_" |
|
|
1930 | Similar to the other two macros, this gives you the value of the default |
|
|
1931 | loop, if multiple loops are supported (\*(L"ev loop default\*(R"). |
|
|
1932 | .PP |
|
|
1933 | Example: Declare and initialise a check watcher, working regardless of |
|
|
1934 | wether multiple loops are supported or not. |
|
|
1935 | .PP |
|
|
1936 | .Vb 5 |
|
|
1937 | \& static void |
|
|
1938 | \& check_cb (EV_P_ ev_timer *w, int revents) |
|
|
1939 | \& { |
|
|
1940 | \& ev_check_stop (EV_A_ w); |
|
|
1941 | \& } |
|
|
1942 | .Ve |
|
|
1943 | .PP |
|
|
1944 | .Vb 4 |
|
|
1945 | \& ev_check check; |
|
|
1946 | \& ev_check_init (&check, check_cb); |
|
|
1947 | \& ev_check_start (EV_DEFAULT_ &check); |
|
|
1948 | \& ev_loop (EV_DEFAULT_ 0); |
|
|
1949 | .Ve |
|
|
1950 | .SH "EMBEDDING" |
|
|
1951 | .IX Header "EMBEDDING" |
|
|
1952 | Libev can (and often is) directly embedded into host |
|
|
1953 | applications. Examples of applications that embed it include the Deliantra |
|
|
1954 | Game Server, the \s-1EV\s0 perl module, the \s-1GNU\s0 Virtual Private Ethernet (gvpe) |
|
|
1955 | and rxvt\-unicode. |
|
|
1956 | .PP |
|
|
1957 | The goal is to enable you to just copy the neecssary files into your |
|
|
1958 | source directory without having to change even a single line in them, so |
|
|
1959 | you can easily upgrade by simply copying (or having a checked-out copy of |
|
|
1960 | libev somewhere in your source tree). |
|
|
1961 | .Sh "\s-1FILESETS\s0" |
|
|
1962 | .IX Subsection "FILESETS" |
|
|
1963 | Depending on what features you need you need to include one or more sets of files |
|
|
1964 | in your app. |
|
|
1965 | .PP |
|
|
1966 | \fI\s-1CORE\s0 \s-1EVENT\s0 \s-1LOOP\s0\fR |
|
|
1967 | .IX Subsection "CORE EVENT LOOP" |
|
|
1968 | .PP |
|
|
1969 | To include only the libev core (all the \f(CW\*(C`ev_*\*(C'\fR functions), with manual |
|
|
1970 | configuration (no autoconf): |
|
|
1971 | .PP |
|
|
1972 | .Vb 2 |
|
|
1973 | \& #define EV_STANDALONE 1 |
|
|
1974 | \& #include "ev.c" |
|
|
1975 | .Ve |
|
|
1976 | .PP |
|
|
1977 | This will automatically include \fIev.h\fR, too, and should be done in a |
|
|
1978 | single C source file only to provide the function implementations. To use |
|
|
1979 | it, do the same for \fIev.h\fR in all files wishing to use this \s-1API\s0 (best |
|
|
1980 | done by writing a wrapper around \fIev.h\fR that you can include instead and |
|
|
1981 | where you can put other configuration options): |
|
|
1982 | .PP |
|
|
1983 | .Vb 2 |
|
|
1984 | \& #define EV_STANDALONE 1 |
|
|
1985 | \& #include "ev.h" |
|
|
1986 | .Ve |
|
|
1987 | .PP |
|
|
1988 | Both header files and implementation files can be compiled with a \*(C+ |
|
|
1989 | compiler (at least, thats a stated goal, and breakage will be treated |
|
|
1990 | as a bug). |
|
|
1991 | .PP |
|
|
1992 | You need the following files in your source tree, or in a directory |
|
|
1993 | in your include path (e.g. in libev/ when using \-Ilibev): |
|
|
1994 | .PP |
|
|
1995 | .Vb 4 |
|
|
1996 | \& ev.h |
|
|
1997 | \& ev.c |
|
|
1998 | \& ev_vars.h |
|
|
1999 | \& ev_wrap.h |
|
|
2000 | .Ve |
|
|
2001 | .PP |
|
|
2002 | .Vb 1 |
|
|
2003 | \& ev_win32.c required on win32 platforms only |
|
|
2004 | .Ve |
|
|
2005 | .PP |
|
|
2006 | .Vb 5 |
|
|
2007 | \& ev_select.c only when select backend is enabled (which is by default) |
|
|
2008 | \& ev_poll.c only when poll backend is enabled (disabled by default) |
|
|
2009 | \& ev_epoll.c only when the epoll backend is enabled (disabled by default) |
|
|
2010 | \& ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
|
|
2011 | \& ev_port.c only when the solaris port backend is enabled (disabled by default) |
|
|
2012 | .Ve |
|
|
2013 | .PP |
|
|
2014 | \&\fIev.c\fR includes the backend files directly when enabled, so you only need |
|
|
2015 | to compile this single file. |
|
|
2016 | .PP |
|
|
2017 | \fI\s-1LIBEVENT\s0 \s-1COMPATIBILITY\s0 \s-1API\s0\fR |
|
|
2018 | .IX Subsection "LIBEVENT COMPATIBILITY API" |
|
|
2019 | .PP |
|
|
2020 | To include the libevent compatibility \s-1API\s0, also include: |
|
|
2021 | .PP |
|
|
2022 | .Vb 1 |
|
|
2023 | \& #include "event.c" |
|
|
2024 | .Ve |
|
|
2025 | .PP |
|
|
2026 | in the file including \fIev.c\fR, and: |
|
|
2027 | .PP |
|
|
2028 | .Vb 1 |
|
|
2029 | \& #include "event.h" |
|
|
2030 | .Ve |
|
|
2031 | .PP |
|
|
2032 | in the files that want to use the libevent \s-1API\s0. This also includes \fIev.h\fR. |
|
|
2033 | .PP |
|
|
2034 | You need the following additional files for this: |
|
|
2035 | .PP |
|
|
2036 | .Vb 2 |
|
|
2037 | \& event.h |
|
|
2038 | \& event.c |
|
|
2039 | .Ve |
|
|
2040 | .PP |
|
|
2041 | \fI\s-1AUTOCONF\s0 \s-1SUPPORT\s0\fR |
|
|
2042 | .IX Subsection "AUTOCONF SUPPORT" |
|
|
2043 | .PP |
|
|
2044 | Instead of using \f(CW\*(C`EV_STANDALONE=1\*(C'\fR and providing your config in |
|
|
2045 | whatever way you want, you can also \f(CW\*(C`m4_include([libev.m4])\*(C'\fR in your |
|
|
2046 | \&\fIconfigure.ac\fR and leave \f(CW\*(C`EV_STANDALONE\*(C'\fR undefined. \fIev.c\fR will then |
|
|
2047 | include \fIconfig.h\fR and configure itself accordingly. |
|
|
2048 | .PP |
|
|
2049 | For this of course you need the m4 file: |
|
|
2050 | .PP |
|
|
2051 | .Vb 1 |
|
|
2052 | \& libev.m4 |
|
|
2053 | .Ve |
|
|
2054 | .Sh "\s-1PREPROCESSOR\s0 \s-1SYMBOLS/MACROS\s0" |
|
|
2055 | .IX Subsection "PREPROCESSOR SYMBOLS/MACROS" |
|
|
2056 | Libev can be configured via a variety of preprocessor symbols you have to define |
|
|
2057 | before including any of its files. The default is not to build for multiplicity |
|
|
2058 | and only include the select backend. |
|
|
2059 | .IP "\s-1EV_STANDALONE\s0" 4 |
|
|
2060 | .IX Item "EV_STANDALONE" |
|
|
2061 | Must always be \f(CW1\fR if you do not use autoconf configuration, which |
|
|
2062 | keeps libev from including \fIconfig.h\fR, and it also defines dummy |
|
|
2063 | implementations for some libevent functions (such as logging, which is not |
|
|
2064 | supported). It will also not define any of the structs usually found in |
|
|
2065 | \&\fIevent.h\fR that are not directly supported by the libev core alone. |
|
|
2066 | .IP "\s-1EV_USE_MONOTONIC\s0" 4 |
|
|
2067 | .IX Item "EV_USE_MONOTONIC" |
|
|
2068 | If defined to be \f(CW1\fR, libev will try to detect the availability of the |
|
|
2069 | monotonic clock option at both compiletime and runtime. Otherwise no use |
|
|
2070 | of the monotonic clock option will be attempted. If you enable this, you |
|
|
2071 | usually have to link against librt or something similar. Enabling it when |
|
|
2072 | the functionality isn't available is safe, though, althoguh you have |
|
|
2073 | to make sure you link against any libraries where the \f(CW\*(C`clock_gettime\*(C'\fR |
|
|
2074 | function is hiding in (often \fI\-lrt\fR). |
|
|
2075 | .IP "\s-1EV_USE_REALTIME\s0" 4 |
|
|
2076 | .IX Item "EV_USE_REALTIME" |
|
|
2077 | If defined to be \f(CW1\fR, libev will try to detect the availability of the |
|
|
2078 | realtime clock option at compiletime (and assume its availability at |
|
|
2079 | runtime if successful). Otherwise no use of the realtime clock option will |
|
|
2080 | be attempted. This effectively replaces \f(CW\*(C`gettimeofday\*(C'\fR by \f(CW\*(C`clock_get |
|
|
2081 | (CLOCK_REALTIME, ...)\*(C'\fR and will not normally affect correctness. See tzhe note about libraries |
|
|
2082 | in the description of \f(CW\*(C`EV_USE_MONOTONIC\*(C'\fR, though. |
|
|
2083 | .IP "\s-1EV_USE_SELECT\s0" 4 |
|
|
2084 | .IX Item "EV_USE_SELECT" |
|
|
2085 | If undefined or defined to be \f(CW1\fR, libev will compile in support for the |
|
|
2086 | \&\f(CW\*(C`select\*(C'\fR(2) backend. No attempt at autodetection will be done: if no |
|
|
2087 | other method takes over, select will be it. Otherwise the select backend |
|
|
2088 | will not be compiled in. |
|
|
2089 | .IP "\s-1EV_SELECT_USE_FD_SET\s0" 4 |
|
|
2090 | .IX Item "EV_SELECT_USE_FD_SET" |
|
|
2091 | If defined to \f(CW1\fR, then the select backend will use the system \f(CW\*(C`fd_set\*(C'\fR |
|
|
2092 | structure. This is useful if libev doesn't compile due to a missing |
|
|
2093 | \&\f(CW\*(C`NFDBITS\*(C'\fR or \f(CW\*(C`fd_mask\*(C'\fR definition or it misguesses the bitset layout on |
|
|
2094 | exotic systems. This usually limits the range of file descriptors to some |
|
|
2095 | low limit such as 1024 or might have other limitations (winsocket only |
|
|
2096 | allows 64 sockets). The \f(CW\*(C`FD_SETSIZE\*(C'\fR macro, set before compilation, might |
|
|
2097 | influence the size of the \f(CW\*(C`fd_set\*(C'\fR used. |
|
|
2098 | .IP "\s-1EV_SELECT_IS_WINSOCKET\s0" 4 |
|
|
2099 | .IX Item "EV_SELECT_IS_WINSOCKET" |
|
|
2100 | When defined to \f(CW1\fR, the select backend will assume that |
|
|
2101 | select/socket/connect etc. don't understand file descriptors but |
|
|
2102 | wants osf handles on win32 (this is the case when the select to |
|
|
2103 | be used is the winsock select). This means that it will call |
|
|
2104 | \&\f(CW\*(C`_get_osfhandle\*(C'\fR on the fd to convert it to an \s-1OS\s0 handle. Otherwise, |
|
|
2105 | it is assumed that all these functions actually work on fds, even |
|
|
2106 | on win32. Should not be defined on non\-win32 platforms. |
|
|
2107 | .IP "\s-1EV_USE_POLL\s0" 4 |
|
|
2108 | .IX Item "EV_USE_POLL" |
|
|
2109 | If defined to be \f(CW1\fR, libev will compile in support for the \f(CW\*(C`poll\*(C'\fR(2) |
|
|
2110 | backend. Otherwise it will be enabled on non\-win32 platforms. It |
|
|
2111 | takes precedence over select. |
|
|
2112 | .IP "\s-1EV_USE_EPOLL\s0" 4 |
|
|
2113 | .IX Item "EV_USE_EPOLL" |
|
|
2114 | If defined to be \f(CW1\fR, libev will compile in support for the Linux |
|
|
2115 | \&\f(CW\*(C`epoll\*(C'\fR(7) backend. Its availability will be detected at runtime, |
|
|
2116 | otherwise another method will be used as fallback. This is the |
|
|
2117 | preferred backend for GNU/Linux systems. |
|
|
2118 | .IP "\s-1EV_USE_KQUEUE\s0" 4 |
|
|
2119 | .IX Item "EV_USE_KQUEUE" |
|
|
2120 | If defined to be \f(CW1\fR, libev will compile in support for the \s-1BSD\s0 style |
|
|
2121 | \&\f(CW\*(C`kqueue\*(C'\fR(2) backend. Its actual availability will be detected at runtime, |
|
|
2122 | otherwise another method will be used as fallback. This is the preferred |
|
|
2123 | backend for \s-1BSD\s0 and BSD-like systems, although on most BSDs kqueue only |
|
|
2124 | supports some types of fds correctly (the only platform we found that |
|
|
2125 | supports ptys for example was NetBSD), so kqueue might be compiled in, but |
|
|
2126 | not be used unless explicitly requested. The best way to use it is to find |
|
|
2127 | out whether kqueue supports your type of fd properly and use an embedded |
|
|
2128 | kqueue loop. |
|
|
2129 | .IP "\s-1EV_USE_PORT\s0" 4 |
|
|
2130 | .IX Item "EV_USE_PORT" |
|
|
2131 | If defined to be \f(CW1\fR, libev will compile in support for the Solaris |
|
|
2132 | 10 port style backend. Its availability will be detected at runtime, |
|
|
2133 | otherwise another method will be used as fallback. This is the preferred |
|
|
2134 | backend for Solaris 10 systems. |
|
|
2135 | .IP "\s-1EV_USE_DEVPOLL\s0" 4 |
|
|
2136 | .IX Item "EV_USE_DEVPOLL" |
|
|
2137 | reserved for future expansion, works like the \s-1USE\s0 symbols above. |
|
|
2138 | .IP "\s-1EV_H\s0" 4 |
|
|
2139 | .IX Item "EV_H" |
|
|
2140 | The name of the \fIev.h\fR header file used to include it. The default if |
|
|
2141 | undefined is \f(CW\*(C`<ev.h>\*(C'\fR in \fIevent.h\fR and \f(CW"ev.h"\fR in \fIev.c\fR. This |
|
|
2142 | can be used to virtually rename the \fIev.h\fR header file in case of conflicts. |
|
|
2143 | .IP "\s-1EV_CONFIG_H\s0" 4 |
|
|
2144 | .IX Item "EV_CONFIG_H" |
|
|
2145 | If \f(CW\*(C`EV_STANDALONE\*(C'\fR isn't \f(CW1\fR, this variable can be used to override |
|
|
2146 | \&\fIev.c\fR's idea of where to find the \fIconfig.h\fR file, similarly to |
|
|
2147 | \&\f(CW\*(C`EV_H\*(C'\fR, above. |
|
|
2148 | .IP "\s-1EV_EVENT_H\s0" 4 |
|
|
2149 | .IX Item "EV_EVENT_H" |
|
|
2150 | Similarly to \f(CW\*(C`EV_H\*(C'\fR, this macro can be used to override \fIevent.c\fR's idea |
|
|
2151 | of how the \fIevent.h\fR header can be found. |
|
|
2152 | .IP "\s-1EV_PROTOTYPES\s0" 4 |
|
|
2153 | .IX Item "EV_PROTOTYPES" |
|
|
2154 | If defined to be \f(CW0\fR, then \fIev.h\fR will not define any function |
|
|
2155 | prototypes, but still define all the structs and other symbols. This is |
|
|
2156 | occasionally useful if you want to provide your own wrapper functions |
|
|
2157 | around libev functions. |
|
|
2158 | .IP "\s-1EV_MULTIPLICITY\s0" 4 |
|
|
2159 | .IX Item "EV_MULTIPLICITY" |
|
|
2160 | If undefined or defined to \f(CW1\fR, then all event-loop-specific functions |
|
|
2161 | will have the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument, and you can create |
|
|
2162 | additional independent event loops. Otherwise there will be no support |
|
|
2163 | for multiple event loops and there is no first event loop pointer |
|
|
2164 | argument. Instead, all functions act on the single default loop. |
|
|
2165 | .IP "\s-1EV_PERIODIC_ENABLE\s0" 4 |
|
|
2166 | .IX Item "EV_PERIODIC_ENABLE" |
|
|
2167 | If undefined or defined to be \f(CW1\fR, then periodic timers are supported. If |
|
|
2168 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
|
|
2169 | code. |
|
|
2170 | .IP "\s-1EV_EMBED_ENABLE\s0" 4 |
|
|
2171 | .IX Item "EV_EMBED_ENABLE" |
|
|
2172 | If undefined or defined to be \f(CW1\fR, then embed watchers are supported. If |
|
|
2173 | defined to be \f(CW0\fR, then they are not. |
|
|
2174 | .IP "\s-1EV_STAT_ENABLE\s0" 4 |
|
|
2175 | .IX Item "EV_STAT_ENABLE" |
|
|
2176 | If undefined or defined to be \f(CW1\fR, then stat watchers are supported. If |
|
|
2177 | defined to be \f(CW0\fR, then they are not. |
|
|
2178 | .IP "\s-1EV_FORK_ENABLE\s0" 4 |
|
|
2179 | .IX Item "EV_FORK_ENABLE" |
|
|
2180 | If undefined or defined to be \f(CW1\fR, then fork watchers are supported. If |
|
|
2181 | defined to be \f(CW0\fR, then they are not. |
|
|
2182 | .IP "\s-1EV_MINIMAL\s0" 4 |
|
|
2183 | .IX Item "EV_MINIMAL" |
|
|
2184 | If you need to shave off some kilobytes of code at the expense of some |
|
|
2185 | speed, define this symbol to \f(CW1\fR. Currently only used for gcc to override |
|
|
2186 | some inlining decisions, saves roughly 30% codesize of amd64. |
|
|
2187 | .IP "\s-1EV_PID_HASHSIZE\s0" 4 |
|
|
2188 | .IX Item "EV_PID_HASHSIZE" |
|
|
2189 | \&\f(CW\*(C`ev_child\*(C'\fR watchers use a small hash table to distribute workload by |
|
|
2190 | pid. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), usually more |
|
|
2191 | than enough. If you need to manage thousands of children you might want to |
|
|
2192 | increase this value. |
|
|
2193 | .IP "\s-1EV_COMMON\s0" 4 |
|
|
2194 | .IX Item "EV_COMMON" |
|
|
2195 | By default, all watchers have a \f(CW\*(C`void *data\*(C'\fR member. By redefining |
|
|
2196 | this macro to a something else you can include more and other types of |
|
|
2197 | members. You have to define it each time you include one of the files, |
|
|
2198 | though, and it must be identical each time. |
|
|
2199 | .Sp |
|
|
2200 | For example, the perl \s-1EV\s0 module uses something like this: |
|
|
2201 | .Sp |
|
|
2202 | .Vb 3 |
|
|
2203 | \& #define EV_COMMON \e |
|
|
2204 | \& SV *self; /* contains this struct */ \e |
|
|
2205 | \& SV *cb_sv, *fh /* note no trailing ";" */ |
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|
2206 | .Ve |
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|
2207 | .IP "\s-1EV_CB_DECLARE\s0 (type)" 4 |
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|
2208 | .IX Item "EV_CB_DECLARE (type)" |
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2209 | .PD 0 |
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2210 | .IP "\s-1EV_CB_INVOKE\s0 (watcher, revents)" 4 |
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2211 | .IX Item "EV_CB_INVOKE (watcher, revents)" |
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2212 | .IP "ev_set_cb (ev, cb)" 4 |
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2213 | .IX Item "ev_set_cb (ev, cb)" |
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2214 | .PD |
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2215 | Can be used to change the callback member declaration in each watcher, |
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2216 | and the way callbacks are invoked and set. Must expand to a struct member |
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2217 | definition and a statement, respectively. See the \fIev.v\fR header file for |
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2218 | their default definitions. One possible use for overriding these is to |
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2219 | avoid the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument in all cases, or to use |
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2220 | method calls instead of plain function calls in \*(C+. |
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2221 | .Sh "\s-1EXAMPLES\s0" |
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2222 | .IX Subsection "EXAMPLES" |
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2223 | For a real-world example of a program the includes libev |
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|
2224 | verbatim, you can have a look at the \s-1EV\s0 perl module |
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|
2225 | (<http://software.schmorp.de/pkg/EV.html>). It has the libev files in |
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2226 | the \fIlibev/\fR subdirectory and includes them in the \fI\s-1EV/EVAPI\s0.h\fR (public |
|
|
2227 | interface) and \fI\s-1EV\s0.xs\fR (implementation) files. Only the \fI\s-1EV\s0.xs\fR file |
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|
2228 | will be compiled. It is pretty complex because it provides its own header |
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2229 | file. |
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|
2230 | .Sp |
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|
2231 | The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file |
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2232 | that everybody includes and which overrides some autoconf choices: |
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|
2233 | .Sp |
|
|
2234 | .Vb 4 |
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|
2235 | \& #define EV_USE_POLL 0 |
|
|
2236 | \& #define EV_MULTIPLICITY 0 |
|
|
2237 | \& #define EV_PERIODICS 0 |
|
|
2238 | \& #define EV_CONFIG_H <config.h> |
|
|
2239 | .Ve |
|
|
2240 | .Sp |
|
|
2241 | .Vb 1 |
|
|
2242 | \& #include "ev++.h" |
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|
2243 | .Ve |
|
|
2244 | .Sp |
|
|
2245 | And a \fIev_cpp.C\fR implementation file that contains libev proper and is compiled: |
|
|
2246 | .Sp |
|
|
2247 | .Vb 2 |
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|
2248 | \& #include "ev_cpp.h" |
|
|
2249 | \& #include "ev.c" |
|
|
2250 | .Ve |
|
|
2251 | .SH "COMPLEXITIES" |
|
|
2252 | .IX Header "COMPLEXITIES" |
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|
2253 | In this section the complexities of (many of) the algorithms used inside |
|
|
2254 | libev will be explained. For complexity discussions about backends see the |
|
|
2255 | documentation for \f(CW\*(C`ev_default_init\*(C'\fR. |
|
|
2256 | .RS 4 |
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|
2257 | .IP "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" 4 |
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|
2258 | .IX Item "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" |
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|
2259 | .PD 0 |
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|
2260 | .IP "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" 4 |
|
|
2261 | .IX Item "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" |
|
|
2262 | .IP "Starting io/check/prepare/idle/signal/child watchers: O(1)" 4 |
|
|
2263 | .IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)" |
|
|
2264 | .IP "Stopping check/prepare/idle watchers: O(1)" 4 |
|
|
2265 | .IX Item "Stopping check/prepare/idle watchers: O(1)" |
|
|
2266 | .IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % 16))" 4 |
|
|
2267 | .IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % 16))" |
|
|
2268 | .IP "Finding the next timer per loop iteration: O(1)" 4 |
|
|
2269 | .IX Item "Finding the next timer per loop iteration: O(1)" |
|
|
2270 | .IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4 |
|
|
2271 | .IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" |
|
|
2272 | .IP "Activating one watcher: O(1)" 4 |
|
|
2273 | .IX Item "Activating one watcher: O(1)" |
|
|
2274 | .RE |
|
|
2275 | .RS 4 |
|
|
2276 | .PD |
976 | .SH "AUTHOR" |
2277 | .SH "AUTHOR" |
977 | .IX Header "AUTHOR" |
2278 | .IX Header "AUTHOR" |
978 | Marc Lehmann <libev@schmorp.de>. |
2279 | Marc Lehmann <libev@schmorp.de>. |