… | |
… | |
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 "2007-11-29" "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), the Linux \f(CW\*(C`inotify\*(C'\fR interface |
159 | events (related to \s-1SIGCHLD\s0), and event watchers dealing with the event |
218 | (for \f(CW\*(C`ev_stat\*(C'\fR), relative timers (\f(CW\*(C`ev_timer\*(C'\fR), absolute timers |
160 | loop mechanism itself (idle, prepare and check watchers). It also is quite |
219 | with customised rescheduling (\f(CW\*(C`ev_periodic\*(C'\fR), synchronous signals |
161 | fast (see this benchmark comparing |
220 | (\f(CW\*(C`ev_signal\*(C'\fR), process status change events (\f(CW\*(C`ev_child\*(C'\fR), and event |
162 | it to libevent for example). |
221 | watchers dealing with the event loop mechanism itself (\f(CW\*(C`ev_idle\*(C'\fR, |
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222 | \&\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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223 | file watchers (\f(CW\*(C`ev_stat\*(C'\fR) and even limited support for fork events |
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224 | (\f(CW\*(C`ev_fork\*(C'\fR). |
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225 | .PP |
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226 | It also is quite fast (see this |
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227 | benchmark comparing it to libevent |
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228 | for example). |
163 | .SH "CONVENTIONS" |
229 | .SH "CONVENTIONS" |
164 | .IX Header "CONVENTIONS" |
230 | .IX Header "CONVENTIONS" |
165 | Libev is very configurable. In this manual the default configuration |
231 | Libev is very configurable. In this manual the default configuration will |
166 | will be described, which supports multiple event loops. For more info |
232 | be described, which supports multiple event loops. For more info about |
167 | about various configuration options please have a look at the file |
233 | 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 |
234 | this manual. If libev was configured without support for multiple event |
169 | support for multiple event loops, then all functions taking an initial |
235 | 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) |
236 | (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" |
237 | .SH "TIME REPRESENTATION" |
173 | .IX Header "TIME REPRESENTATION" |
238 | .IX Header "TIME REPRESENTATION" |
174 | Libev represents time as a single floating point number, representing the |
239 | Libev represents time as a single floating point number, representing the |
175 | (fractional) number of seconds since the (\s-1POSIX\s0) epoch (somewhere near |
240 | (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 |
241 | 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 |
242 | 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. |
243 | to the \f(CW\*(C`double\*(C'\fR type in C, and when you need to do any calculations on |
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244 | it, you should treat it as such. |
179 | .SH "GLOBAL FUNCTIONS" |
245 | .SH "GLOBAL FUNCTIONS" |
180 | .IX Header "GLOBAL FUNCTIONS" |
246 | .IX Header "GLOBAL FUNCTIONS" |
181 | These functions can be called anytime, even before initialising the |
247 | These functions can be called anytime, even before initialising the |
182 | library in any way. |
248 | library in any way. |
183 | .IP "ev_tstamp ev_time ()" 4 |
249 | .IP "ev_tstamp ev_time ()" 4 |
… | |
… | |
199 | .Sp |
265 | .Sp |
200 | Usually, it's a good idea to terminate if the major versions mismatch, |
266 | Usually, it's a good idea to terminate if the major versions mismatch, |
201 | as this indicates an incompatible change. Minor versions are usually |
267 | as this indicates an incompatible change. Minor versions are usually |
202 | compatible to older versions, so a larger minor version alone is usually |
268 | compatible to older versions, so a larger minor version alone is usually |
203 | not a problem. |
269 | not a problem. |
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270 | .Sp |
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271 | Example: Make sure we haven't accidentally been linked against the wrong |
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272 | version. |
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273 | .Sp |
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274 | .Vb 3 |
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275 | \& assert (("libev version mismatch", |
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276 | \& ev_version_major () == EV_VERSION_MAJOR |
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277 | \& && ev_version_minor () >= EV_VERSION_MINOR)); |
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278 | .Ve |
204 | .IP "unsigned int ev_supported_backends ()" 4 |
279 | .IP "unsigned int ev_supported_backends ()" 4 |
205 | .IX Item "unsigned int ev_supported_backends ()" |
280 | .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 |
281 | 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 |
282 | 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 |
283 | 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. |
284 | a description of the set values. |
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285 | .Sp |
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286 | Example: make sure we have the epoll method, because yeah this is cool and |
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287 | a must have and can we have a torrent of it please!!!11 |
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288 | .Sp |
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289 | .Vb 2 |
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290 | \& assert (("sorry, no epoll, no sex", |
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291 | \& ev_supported_backends () & EVBACKEND_EPOLL)); |
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292 | .Ve |
210 | .IP "unsigned int ev_recommended_backends ()" 4 |
293 | .IP "unsigned int ev_recommended_backends ()" 4 |
211 | .IX Item "unsigned int ev_recommended_backends ()" |
294 | .IX Item "unsigned int ev_recommended_backends ()" |
212 | Return the set of all backends compiled into this binary of libev and also |
295 | 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 |
296 | 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 |
297 | 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 |
298 | 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 |
299 | (assuming you know what you are doing). This is the set of backends that |
217 | libev will probe for if you specify no backends explicitly. |
300 | libev will probe for if you specify no backends explicitly. |
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301 | .IP "unsigned int ev_embeddable_backends ()" 4 |
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302 | .IX Item "unsigned int ev_embeddable_backends ()" |
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303 | Returns the set of backends that are embeddable in other event loops. This |
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304 | is the theoretical, all\-platform, value. To find which backends |
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305 | might be supported on the current system, you would need to look at |
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306 | \&\f(CW\*(C`ev_embeddable_backends () & ev_supported_backends ()\*(C'\fR, likewise for |
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307 | recommended ones. |
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308 | .Sp |
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309 | 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 |
310 | .IP "ev_set_allocator (void *(*cb)(void *ptr, long size))" 4 |
219 | .IX Item "ev_set_allocator (void *(*cb)(void *ptr, long size))" |
311 | .IX Item "ev_set_allocator (void *(*cb)(void *ptr, long size))" |
220 | Sets the allocation function to use (the prototype is similar to the |
312 | Sets the allocation function to use (the prototype is similar \- the |
221 | realloc C function, the semantics are identical). It is used to allocate |
313 | semantics is identical \- to the realloc C function). It is used to |
222 | and free memory (no surprises here). If it returns zero when memory |
314 | allocate and free memory (no surprises here). If it returns zero when |
223 | needs to be allocated, the library might abort or take some potentially |
315 | memory needs to be allocated, the library might abort or take some |
224 | destructive action. The default is your system realloc function. |
316 | potentially destructive action. The default is your system realloc |
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317 | function. |
225 | .Sp |
318 | .Sp |
226 | You could override this function in high-availability programs to, say, |
319 | 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, |
320 | 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. |
321 | or even to sleep a while and retry until some memory is available. |
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322 | .Sp |
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323 | Example: Replace the libev allocator with one that waits a bit and then |
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324 | retries). |
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325 | .Sp |
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326 | .Vb 6 |
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327 | \& static void * |
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328 | \& persistent_realloc (void *ptr, size_t size) |
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329 | \& { |
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330 | \& for (;;) |
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331 | \& { |
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332 | \& void *newptr = realloc (ptr, size); |
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333 | .Ve |
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334 | .Sp |
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335 | .Vb 2 |
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336 | \& if (newptr) |
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337 | \& return newptr; |
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338 | .Ve |
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339 | .Sp |
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340 | .Vb 3 |
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341 | \& sleep (60); |
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342 | \& } |
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343 | \& } |
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344 | .Ve |
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345 | .Sp |
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346 | .Vb 2 |
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347 | \& ... |
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348 | \& ev_set_allocator (persistent_realloc); |
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349 | .Ve |
229 | .IP "ev_set_syserr_cb (void (*cb)(const char *msg));" 4 |
350 | .IP "ev_set_syserr_cb (void (*cb)(const char *msg));" 4 |
230 | .IX Item "ev_set_syserr_cb (void (*cb)(const char *msg));" |
351 | .IX Item "ev_set_syserr_cb (void (*cb)(const char *msg));" |
231 | Set the callback function to call on a retryable syscall error (such |
352 | 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 |
353 | as failed select, poll, epoll_wait). The message is a printable string |
233 | indicating the system call or subsystem causing the problem. If this |
354 | 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 |
355 | 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 |
356 | 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 |
357 | requested operation, or, if the condition doesn't go away, do bad stuff |
237 | (such as abort). |
358 | (such as abort). |
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359 | .Sp |
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360 | Example: This is basically the same thing that libev does internally, too. |
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361 | .Sp |
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362 | .Vb 6 |
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363 | \& static void |
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364 | \& fatal_error (const char *msg) |
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365 | \& { |
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366 | \& perror (msg); |
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367 | \& abort (); |
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368 | \& } |
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369 | .Ve |
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370 | .Sp |
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371 | .Vb 2 |
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372 | \& ... |
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373 | \& ev_set_syserr_cb (fatal_error); |
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374 | .Ve |
238 | .SH "FUNCTIONS CONTROLLING THE EVENT LOOP" |
375 | .SH "FUNCTIONS CONTROLLING THE EVENT LOOP" |
239 | .IX Header "FUNCTIONS CONTROLLING THE EVENT LOOP" |
376 | .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 |
377 | 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 |
378 | types of such loops, the \fIdefault\fR loop, which supports signals and child |
242 | events, and dynamically created loops which do not. |
379 | events, and dynamically created loops which do not. |
… | |
… | |
274 | or setgid) then libev will \fInot\fR look at the environment variable |
411 | or setgid) then libev will \fInot\fR look at the environment variable |
275 | \&\f(CW\*(C`LIBEV_FLAGS\*(C'\fR. Otherwise (the default), this environment variable will |
412 | \&\f(CW\*(C`LIBEV_FLAGS\*(C'\fR. Otherwise (the default), this environment variable will |
276 | override the flags completely if it is found in the environment. This is |
413 | override the flags completely if it is found in the environment. This is |
277 | useful to try out specific backends to test their performance, or to work |
414 | useful to try out specific backends to test their performance, or to work |
278 | around bugs. |
415 | around bugs. |
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416 | .ie n .IP """EVFLAG_FORKCHECK""" 4 |
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417 | .el .IP "\f(CWEVFLAG_FORKCHECK\fR" 4 |
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418 | .IX Item "EVFLAG_FORKCHECK" |
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419 | Instead of calling \f(CW\*(C`ev_default_fork\*(C'\fR or \f(CW\*(C`ev_loop_fork\*(C'\fR manually after |
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420 | a fork, you can also make libev check for a fork in each iteration by |
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421 | enabling this flag. |
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422 | .Sp |
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423 | This works by calling \f(CW\*(C`getpid ()\*(C'\fR on every iteration of the loop, |
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424 | and thus this might slow down your event loop if you do a lot of loop |
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425 | iterations and little real work, but is usually not noticable (on my |
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426 | Linux system for example, \f(CW\*(C`getpid\*(C'\fR is actually a simple 5\-insn sequence |
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427 | without a syscall and thus \fIvery\fR fast, but my Linux system also has |
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428 | \&\f(CW\*(C`pthread_atfork\*(C'\fR which is even faster). |
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429 | .Sp |
|
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430 | The big advantage of this flag is that you can forget about fork (and |
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431 | forget about forgetting to tell libev about forking) when you use this |
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432 | flag. |
|
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433 | .Sp |
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434 | This flag setting cannot be overriden or specified in the \f(CW\*(C`LIBEV_FLAGS\*(C'\fR |
|
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435 | environment variable. |
279 | .ie n .IP """EVBACKEND_SELECT"" (value 1, portable select backend)" 4 |
436 | .ie n .IP """EVBACKEND_SELECT"" (value 1, portable select backend)" 4 |
280 | .el .IP "\f(CWEVBACKEND_SELECT\fR (value 1, portable select backend)" 4 |
437 | .el .IP "\f(CWEVBACKEND_SELECT\fR (value 1, portable select backend)" 4 |
281 | .IX Item "EVBACKEND_SELECT (value 1, portable select backend)" |
438 | .IX Item "EVBACKEND_SELECT (value 1, portable select backend)" |
282 | This is your standard \fIselect\fR\|(2) backend. Not \fIcompletely\fR standard, as |
439 | This is your standard \fIselect\fR\|(2) backend. Not \fIcompletely\fR standard, as |
283 | libev tries to roll its own fd_set with no limits on the number of fds, |
440 | libev tries to roll its own fd_set with no limits on the number of fds, |
… | |
… | |
376 | .IX Item "struct ev_loop *ev_loop_new (unsigned int flags)" |
533 | .IX Item "struct ev_loop *ev_loop_new (unsigned int flags)" |
377 | Similar to \f(CW\*(C`ev_default_loop\*(C'\fR, but always creates a new event loop that is |
534 | Similar to \f(CW\*(C`ev_default_loop\*(C'\fR, but always creates a new event loop that is |
378 | always distinct from the default loop. Unlike the default loop, it cannot |
535 | always distinct from the default loop. Unlike the default loop, it cannot |
379 | handle signal and child watchers, and attempts to do so will be greeted by |
536 | handle signal and child watchers, and attempts to do so will be greeted by |
380 | undefined behaviour (or a failed assertion if assertions are enabled). |
537 | undefined behaviour (or a failed assertion if assertions are enabled). |
|
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538 | .Sp |
|
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539 | Example: Try to create a event loop that uses epoll and nothing else. |
|
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540 | .Sp |
|
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541 | .Vb 3 |
|
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542 | \& struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
|
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543 | \& if (!epoller) |
|
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544 | \& fatal ("no epoll found here, maybe it hides under your chair"); |
|
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545 | .Ve |
381 | .IP "ev_default_destroy ()" 4 |
546 | .IP "ev_default_destroy ()" 4 |
382 | .IX Item "ev_default_destroy ()" |
547 | .IX Item "ev_default_destroy ()" |
383 | Destroys the default loop again (frees all memory and kernel state |
548 | Destroys the default loop again (frees all memory and kernel state |
384 | etc.). This stops all registered event watchers (by not touching them in |
549 | etc.). None of the active event watchers will be stopped in the normal |
385 | any way whatsoever, although you cannot rely on this :). |
550 | sense, so e.g. \f(CW\*(C`ev_is_active\*(C'\fR might still return true. It is your |
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551 | responsibility to either stop all watchers cleanly yoursef \fIbefore\fR |
|
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552 | calling this function, or cope with the fact afterwards (which is usually |
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553 | the easiest thing, youc na just ignore the watchers and/or \f(CW\*(C`free ()\*(C'\fR them |
|
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554 | for example). |
386 | .IP "ev_loop_destroy (loop)" 4 |
555 | .IP "ev_loop_destroy (loop)" 4 |
387 | .IX Item "ev_loop_destroy (loop)" |
556 | .IX Item "ev_loop_destroy (loop)" |
388 | Like \f(CW\*(C`ev_default_destroy\*(C'\fR, but destroys an event loop created by an |
557 | Like \f(CW\*(C`ev_default_destroy\*(C'\fR, but destroys an event loop created by an |
389 | earlier call to \f(CW\*(C`ev_loop_new\*(C'\fR. |
558 | earlier call to \f(CW\*(C`ev_loop_new\*(C'\fR. |
390 | .IP "ev_default_fork ()" 4 |
559 | .IP "ev_default_fork ()" 4 |
… | |
… | |
419 | Returns one of the \f(CW\*(C`EVBACKEND_*\*(C'\fR flags indicating the event backend in |
588 | Returns one of the \f(CW\*(C`EVBACKEND_*\*(C'\fR flags indicating the event backend in |
420 | use. |
589 | use. |
421 | .IP "ev_tstamp ev_now (loop)" 4 |
590 | .IP "ev_tstamp ev_now (loop)" 4 |
422 | .IX Item "ev_tstamp ev_now (loop)" |
591 | .IX Item "ev_tstamp ev_now (loop)" |
423 | Returns the current \*(L"event loop time\*(R", which is the time the event loop |
592 | Returns the current \*(L"event loop time\*(R", which is the time the event loop |
424 | got events and started processing them. This timestamp does not change |
593 | received events and started processing them. This timestamp does not |
425 | as long as callbacks are being processed, and this is also the base time |
594 | change as long as callbacks are being processed, and this is also the base |
426 | used for relative timers. You can treat it as the timestamp of the event |
595 | time used for relative timers. You can treat it as the timestamp of the |
427 | occuring (or more correctly, the mainloop finding out about it). |
596 | event occuring (or more correctly, libev finding out about it). |
428 | .IP "ev_loop (loop, int flags)" 4 |
597 | .IP "ev_loop (loop, int flags)" 4 |
429 | .IX Item "ev_loop (loop, int flags)" |
598 | .IX Item "ev_loop (loop, int flags)" |
430 | Finally, this is it, the event handler. This function usually is called |
599 | Finally, this is it, the event handler. This function usually is called |
431 | after you initialised all your watchers and you want to start handling |
600 | after you initialised all your watchers and you want to start handling |
432 | events. |
601 | events. |
433 | .Sp |
602 | .Sp |
434 | If the flags argument is specified as \f(CW0\fR, it will not return until |
603 | If the flags argument is specified as \f(CW0\fR, it will not return until |
435 | either no event watchers are active anymore or \f(CW\*(C`ev_unloop\*(C'\fR was called. |
604 | either no event watchers are active anymore or \f(CW\*(C`ev_unloop\*(C'\fR was called. |
|
|
605 | .Sp |
|
|
606 | Please note that an explicit \f(CW\*(C`ev_unloop\*(C'\fR is usually better than |
|
|
607 | relying on all watchers to be stopped when deciding when a program has |
|
|
608 | finished (especially in interactive programs), but having a program that |
|
|
609 | automatically loops as long as it has to and no longer by virtue of |
|
|
610 | relying on its watchers stopping correctly is a thing of beauty. |
436 | .Sp |
611 | .Sp |
437 | A flags value of \f(CW\*(C`EVLOOP_NONBLOCK\*(C'\fR will look for new events, will handle |
612 | A flags value of \f(CW\*(C`EVLOOP_NONBLOCK\*(C'\fR will look for new events, will handle |
438 | those events and any outstanding ones, but will not block your process in |
613 | those events and any outstanding ones, but will not block your process in |
439 | case there are no events and will return after one iteration of the loop. |
614 | case there are no events and will return after one iteration of the loop. |
440 | .Sp |
615 | .Sp |
… | |
… | |
465 | \& - Call all queued watchers in reverse order (i.e. check watchers first). |
640 | \& - Call all queued watchers in reverse order (i.e. check watchers first). |
466 | \& Signals and child watchers are implemented as I/O watchers, and will |
641 | \& Signals and child watchers are implemented as I/O watchers, and will |
467 | \& be handled here by queueing them when their watcher gets executed. |
642 | \& be handled here by queueing them when their watcher gets executed. |
468 | \& - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
643 | \& - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
469 | \& were used, return, otherwise continue with step *. |
644 | \& were used, return, otherwise continue with step *. |
|
|
645 | .Ve |
|
|
646 | .Sp |
|
|
647 | Example: Queue some jobs and then loop until no events are outsanding |
|
|
648 | anymore. |
|
|
649 | .Sp |
|
|
650 | .Vb 4 |
|
|
651 | \& ... queue jobs here, make sure they register event watchers as long |
|
|
652 | \& ... as they still have work to do (even an idle watcher will do..) |
|
|
653 | \& ev_loop (my_loop, 0); |
|
|
654 | \& ... jobs done. yeah! |
470 | .Ve |
655 | .Ve |
471 | .IP "ev_unloop (loop, how)" 4 |
656 | .IP "ev_unloop (loop, how)" 4 |
472 | .IX Item "ev_unloop (loop, how)" |
657 | .IX Item "ev_unloop (loop, how)" |
473 | Can be used to make a call to \f(CW\*(C`ev_loop\*(C'\fR return early (but only after it |
658 | Can be used to make a call to \f(CW\*(C`ev_loop\*(C'\fR return early (but only after it |
474 | has processed all outstanding events). The \f(CW\*(C`how\*(C'\fR argument must be either |
659 | has processed all outstanding events). The \f(CW\*(C`how\*(C'\fR argument must be either |
… | |
… | |
488 | example, libev itself uses this for its internal signal pipe: It is not |
673 | example, libev itself uses this for its internal signal pipe: It is not |
489 | visible to the libev user and should not keep \f(CW\*(C`ev_loop\*(C'\fR from exiting if |
674 | visible to the libev user and should not keep \f(CW\*(C`ev_loop\*(C'\fR from exiting if |
490 | no event watchers registered by it are active. It is also an excellent |
675 | no event watchers registered by it are active. It is also an excellent |
491 | way to do this for generic recurring timers or from within third-party |
676 | way to do this for generic recurring timers or from within third-party |
492 | libraries. Just remember to \fIunref after start\fR and \fIref before stop\fR. |
677 | libraries. Just remember to \fIunref after start\fR and \fIref before stop\fR. |
|
|
678 | .Sp |
|
|
679 | Example: Create a signal watcher, but keep it from keeping \f(CW\*(C`ev_loop\*(C'\fR |
|
|
680 | running when nothing else is active. |
|
|
681 | .Sp |
|
|
682 | .Vb 4 |
|
|
683 | \& struct ev_signal exitsig; |
|
|
684 | \& ev_signal_init (&exitsig, sig_cb, SIGINT); |
|
|
685 | \& ev_signal_start (loop, &exitsig); |
|
|
686 | \& evf_unref (loop); |
|
|
687 | .Ve |
|
|
688 | .Sp |
|
|
689 | Example: For some weird reason, unregister the above signal handler again. |
|
|
690 | .Sp |
|
|
691 | .Vb 2 |
|
|
692 | \& ev_ref (loop); |
|
|
693 | \& ev_signal_stop (loop, &exitsig); |
|
|
694 | .Ve |
493 | .SH "ANATOMY OF A WATCHER" |
695 | .SH "ANATOMY OF A WATCHER" |
494 | .IX Header "ANATOMY OF A WATCHER" |
696 | .IX Header "ANATOMY OF A WATCHER" |
495 | A watcher is a structure that you create and register to record your |
697 | A watcher is a structure that you create and register to record your |
496 | interest in some event. For instance, if you want to wait for \s-1STDIN\s0 to |
698 | interest in some event. For instance, if you want to wait for \s-1STDIN\s0 to |
497 | become readable, you would create an \f(CW\*(C`ev_io\*(C'\fR watcher for that: |
699 | become readable, you would create an \f(CW\*(C`ev_io\*(C'\fR watcher for that: |
… | |
… | |
533 | *)\*(C'\fR), and you can stop watching for events at any time by calling the |
735 | *)\*(C'\fR), and you can stop watching for events at any time by calling the |
534 | corresponding stop function (\f(CW\*(C`ev_<type>_stop (loop, watcher *)\*(C'\fR. |
736 | corresponding stop function (\f(CW\*(C`ev_<type>_stop (loop, watcher *)\*(C'\fR. |
535 | .PP |
737 | .PP |
536 | As long as your watcher is active (has been started but not stopped) you |
738 | As long as your watcher is active (has been started but not stopped) you |
537 | must not touch the values stored in it. Most specifically you must never |
739 | must not touch the values stored in it. Most specifically you must never |
538 | reinitialise it or call its set macro. |
740 | reinitialise it or call its \f(CW\*(C`set\*(C'\fR macro. |
539 | .PP |
|
|
540 | You can check whether an event is active by calling the \f(CW\*(C`ev_is_active |
|
|
541 | (watcher *)\*(C'\fR macro. To see whether an event is outstanding (but the |
|
|
542 | callback for it has not been called yet) you can use the \f(CW\*(C`ev_is_pending |
|
|
543 | (watcher *)\*(C'\fR macro. |
|
|
544 | .PP |
741 | .PP |
545 | Each and every callback receives the event loop pointer as first, the |
742 | Each and every callback receives the event loop pointer as first, the |
546 | registered watcher structure as second, and a bitset of received events as |
743 | registered watcher structure as second, and a bitset of received events as |
547 | third argument. |
744 | third argument. |
548 | .PP |
745 | .PP |
… | |
… | |
573 | The signal specified in the \f(CW\*(C`ev_signal\*(C'\fR watcher has been received by a thread. |
770 | The signal specified in the \f(CW\*(C`ev_signal\*(C'\fR watcher has been received by a thread. |
574 | .ie n .IP """EV_CHILD""" 4 |
771 | .ie n .IP """EV_CHILD""" 4 |
575 | .el .IP "\f(CWEV_CHILD\fR" 4 |
772 | .el .IP "\f(CWEV_CHILD\fR" 4 |
576 | .IX Item "EV_CHILD" |
773 | .IX Item "EV_CHILD" |
577 | The pid specified in the \f(CW\*(C`ev_child\*(C'\fR watcher has received a status change. |
774 | The pid specified in the \f(CW\*(C`ev_child\*(C'\fR watcher has received a status change. |
|
|
775 | .ie n .IP """EV_STAT""" 4 |
|
|
776 | .el .IP "\f(CWEV_STAT\fR" 4 |
|
|
777 | .IX Item "EV_STAT" |
|
|
778 | The path specified in the \f(CW\*(C`ev_stat\*(C'\fR watcher changed its attributes somehow. |
578 | .ie n .IP """EV_IDLE""" 4 |
779 | .ie n .IP """EV_IDLE""" 4 |
579 | .el .IP "\f(CWEV_IDLE\fR" 4 |
780 | .el .IP "\f(CWEV_IDLE\fR" 4 |
580 | .IX Item "EV_IDLE" |
781 | .IX Item "EV_IDLE" |
581 | The \f(CW\*(C`ev_idle\*(C'\fR watcher has determined that you have nothing better to do. |
782 | The \f(CW\*(C`ev_idle\*(C'\fR watcher has determined that you have nothing better to do. |
582 | .ie n .IP """EV_PREPARE""" 4 |
783 | .ie n .IP """EV_PREPARE""" 4 |
… | |
… | |
592 | \&\f(CW\*(C`ev_loop\*(C'\fR has gathered them, but before it invokes any callbacks for any |
793 | \&\f(CW\*(C`ev_loop\*(C'\fR has gathered them, but before it invokes any callbacks for any |
593 | received events. Callbacks of both watcher types can start and stop as |
794 | received events. Callbacks of both watcher types can start and stop as |
594 | many watchers as they want, and all of them will be taken into account |
795 | many watchers as they want, and all of them will be taken into account |
595 | (for example, a \f(CW\*(C`ev_prepare\*(C'\fR watcher might start an idle watcher to keep |
796 | (for example, a \f(CW\*(C`ev_prepare\*(C'\fR watcher might start an idle watcher to keep |
596 | \&\f(CW\*(C`ev_loop\*(C'\fR from blocking). |
797 | \&\f(CW\*(C`ev_loop\*(C'\fR from blocking). |
|
|
798 | .ie n .IP """EV_EMBED""" 4 |
|
|
799 | .el .IP "\f(CWEV_EMBED\fR" 4 |
|
|
800 | .IX Item "EV_EMBED" |
|
|
801 | The embedded event loop specified in the \f(CW\*(C`ev_embed\*(C'\fR watcher needs attention. |
|
|
802 | .ie n .IP """EV_FORK""" 4 |
|
|
803 | .el .IP "\f(CWEV_FORK\fR" 4 |
|
|
804 | .IX Item "EV_FORK" |
|
|
805 | The event loop has been resumed in the child process after fork (see |
|
|
806 | \&\f(CW\*(C`ev_fork\*(C'\fR). |
597 | .ie n .IP """EV_ERROR""" 4 |
807 | .ie n .IP """EV_ERROR""" 4 |
598 | .el .IP "\f(CWEV_ERROR\fR" 4 |
808 | .el .IP "\f(CWEV_ERROR\fR" 4 |
599 | .IX Item "EV_ERROR" |
809 | .IX Item "EV_ERROR" |
600 | An unspecified error has occured, the watcher has been stopped. This might |
810 | An unspecified error has occured, the watcher has been stopped. This might |
601 | happen because the watcher could not be properly started because libev |
811 | happen because the watcher could not be properly started because libev |
… | |
… | |
606 | Libev will usually signal a few \*(L"dummy\*(R" events together with an error, |
816 | Libev will usually signal a few \*(L"dummy\*(R" events together with an error, |
607 | for example it might indicate that a fd is readable or writable, and if |
817 | for example it might indicate that a fd is readable or writable, and if |
608 | your callbacks is well-written it can just attempt the operation and cope |
818 | your callbacks is well-written it can just attempt the operation and cope |
609 | with the error from \fIread()\fR or \fIwrite()\fR. This will not work in multithreaded |
819 | with the error from \fIread()\fR or \fIwrite()\fR. This will not work in multithreaded |
610 | programs, though, so beware. |
820 | programs, though, so beware. |
|
|
821 | .Sh "\s-1GENERIC\s0 \s-1WATCHER\s0 \s-1FUNCTIONS\s0" |
|
|
822 | .IX Subsection "GENERIC WATCHER FUNCTIONS" |
|
|
823 | In the following description, \f(CW\*(C`TYPE\*(C'\fR stands for the watcher type, |
|
|
824 | 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. |
|
|
825 | .ie n .IP """ev_init"" (ev_TYPE *watcher, callback)" 4 |
|
|
826 | .el .IP "\f(CWev_init\fR (ev_TYPE *watcher, callback)" 4 |
|
|
827 | .IX Item "ev_init (ev_TYPE *watcher, callback)" |
|
|
828 | This macro initialises the generic portion of a watcher. The contents |
|
|
829 | of the watcher object can be arbitrary (so \f(CW\*(C`malloc\*(C'\fR will do). Only |
|
|
830 | the generic parts of the watcher are initialised, you \fIneed\fR to call |
|
|
831 | the type-specific \f(CW\*(C`ev_TYPE_set\*(C'\fR macro afterwards to initialise the |
|
|
832 | type-specific parts. For each type there is also a \f(CW\*(C`ev_TYPE_init\*(C'\fR macro |
|
|
833 | which rolls both calls into one. |
|
|
834 | .Sp |
|
|
835 | You can reinitialise a watcher at any time as long as it has been stopped |
|
|
836 | (or never started) and there are no pending events outstanding. |
|
|
837 | .Sp |
|
|
838 | The callback is always of type \f(CW\*(C`void (*)(ev_loop *loop, ev_TYPE *watcher, |
|
|
839 | int revents)\*(C'\fR. |
|
|
840 | .ie n .IP """ev_TYPE_set"" (ev_TYPE *, [args])" 4 |
|
|
841 | .el .IP "\f(CWev_TYPE_set\fR (ev_TYPE *, [args])" 4 |
|
|
842 | .IX Item "ev_TYPE_set (ev_TYPE *, [args])" |
|
|
843 | This macro initialises the type-specific parts of a watcher. You need to |
|
|
844 | call \f(CW\*(C`ev_init\*(C'\fR at least once before you call this macro, but you can |
|
|
845 | call \f(CW\*(C`ev_TYPE_set\*(C'\fR any number of times. You must not, however, call this |
|
|
846 | macro on a watcher that is active (it can be pending, however, which is a |
|
|
847 | difference to the \f(CW\*(C`ev_init\*(C'\fR macro). |
|
|
848 | .Sp |
|
|
849 | Although some watcher types do not have type-specific arguments |
|
|
850 | (e.g. \f(CW\*(C`ev_prepare\*(C'\fR) you still need to call its \f(CW\*(C`set\*(C'\fR macro. |
|
|
851 | .ie n .IP """ev_TYPE_init"" (ev_TYPE *watcher, callback, [args])" 4 |
|
|
852 | .el .IP "\f(CWev_TYPE_init\fR (ev_TYPE *watcher, callback, [args])" 4 |
|
|
853 | .IX Item "ev_TYPE_init (ev_TYPE *watcher, callback, [args])" |
|
|
854 | This convinience macro rolls both \f(CW\*(C`ev_init\*(C'\fR and \f(CW\*(C`ev_TYPE_set\*(C'\fR macro |
|
|
855 | calls into a single call. This is the most convinient method to initialise |
|
|
856 | a watcher. The same limitations apply, of course. |
|
|
857 | .ie n .IP """ev_TYPE_start"" (loop *, ev_TYPE *watcher)" 4 |
|
|
858 | .el .IP "\f(CWev_TYPE_start\fR (loop *, ev_TYPE *watcher)" 4 |
|
|
859 | .IX Item "ev_TYPE_start (loop *, ev_TYPE *watcher)" |
|
|
860 | Starts (activates) the given watcher. Only active watchers will receive |
|
|
861 | events. If the watcher is already active nothing will happen. |
|
|
862 | .ie n .IP """ev_TYPE_stop"" (loop *, ev_TYPE *watcher)" 4 |
|
|
863 | .el .IP "\f(CWev_TYPE_stop\fR (loop *, ev_TYPE *watcher)" 4 |
|
|
864 | .IX Item "ev_TYPE_stop (loop *, ev_TYPE *watcher)" |
|
|
865 | Stops the given watcher again (if active) and clears the pending |
|
|
866 | status. It is possible that stopped watchers are pending (for example, |
|
|
867 | non-repeating timers are being stopped when they become pending), but |
|
|
868 | \&\f(CW\*(C`ev_TYPE_stop\*(C'\fR ensures that the watcher is neither active nor pending. If |
|
|
869 | you want to free or reuse the memory used by the watcher it is therefore a |
|
|
870 | good idea to always call its \f(CW\*(C`ev_TYPE_stop\*(C'\fR function. |
|
|
871 | .IP "bool ev_is_active (ev_TYPE *watcher)" 4 |
|
|
872 | .IX Item "bool ev_is_active (ev_TYPE *watcher)" |
|
|
873 | Returns a true value iff the watcher is active (i.e. it has been started |
|
|
874 | and not yet been stopped). As long as a watcher is active you must not modify |
|
|
875 | it. |
|
|
876 | .IP "bool ev_is_pending (ev_TYPE *watcher)" 4 |
|
|
877 | .IX Item "bool ev_is_pending (ev_TYPE *watcher)" |
|
|
878 | Returns a true value iff the watcher is pending, (i.e. it has outstanding |
|
|
879 | events but its callback has not yet been invoked). As long as a watcher |
|
|
880 | is pending (but not active) you must not call an init function on it (but |
|
|
881 | \&\f(CW\*(C`ev_TYPE_set\*(C'\fR is safe) and you must make sure the watcher is available to |
|
|
882 | libev (e.g. you cnanot \f(CW\*(C`free ()\*(C'\fR it). |
|
|
883 | .IP "callback ev_cb (ev_TYPE *watcher)" 4 |
|
|
884 | .IX Item "callback ev_cb (ev_TYPE *watcher)" |
|
|
885 | Returns the callback currently set on the watcher. |
|
|
886 | .IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 |
|
|
887 | .IX Item "ev_cb_set (ev_TYPE *watcher, callback)" |
|
|
888 | Change the callback. You can change the callback at virtually any time |
|
|
889 | (modulo threads). |
611 | .Sh "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0" |
890 | .Sh "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0" |
612 | .IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER" |
891 | .IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER" |
613 | Each watcher has, by default, a member \f(CW\*(C`void *data\*(C'\fR that you can change |
892 | Each watcher has, by default, a member \f(CW\*(C`void *data\*(C'\fR that you can change |
614 | and read at any time, libev will completely ignore it. This can be used |
893 | and read at any time, libev will completely ignore it. This can be used |
615 | to associate arbitrary data with your watcher. If you need more data and |
894 | to associate arbitrary data with your watcher. If you need more data and |
… | |
… | |
636 | \& struct my_io *w = (struct my_io *)w_; |
915 | \& struct my_io *w = (struct my_io *)w_; |
637 | \& ... |
916 | \& ... |
638 | \& } |
917 | \& } |
639 | .Ve |
918 | .Ve |
640 | .PP |
919 | .PP |
641 | More interesting and less C\-conformant ways of catsing your callback type |
920 | More interesting and less C\-conformant ways of casting your callback type |
642 | have been omitted.... |
921 | instead have been omitted. |
|
|
922 | .PP |
|
|
923 | Another common scenario is having some data structure with multiple |
|
|
924 | watchers: |
|
|
925 | .PP |
|
|
926 | .Vb 6 |
|
|
927 | \& struct my_biggy |
|
|
928 | \& { |
|
|
929 | \& int some_data; |
|
|
930 | \& ev_timer t1; |
|
|
931 | \& ev_timer t2; |
|
|
932 | \& } |
|
|
933 | .Ve |
|
|
934 | .PP |
|
|
935 | In this case getting the pointer to \f(CW\*(C`my_biggy\*(C'\fR is a bit more complicated, |
|
|
936 | you need to use \f(CW\*(C`offsetof\*(C'\fR: |
|
|
937 | .PP |
|
|
938 | .Vb 1 |
|
|
939 | \& #include <stddef.h> |
|
|
940 | .Ve |
|
|
941 | .PP |
|
|
942 | .Vb 6 |
|
|
943 | \& static void |
|
|
944 | \& t1_cb (EV_P_ struct ev_timer *w, int revents) |
|
|
945 | \& { |
|
|
946 | \& struct my_biggy big = (struct my_biggy * |
|
|
947 | \& (((char *)w) - offsetof (struct my_biggy, t1)); |
|
|
948 | \& } |
|
|
949 | .Ve |
|
|
950 | .PP |
|
|
951 | .Vb 6 |
|
|
952 | \& static void |
|
|
953 | \& t2_cb (EV_P_ struct ev_timer *w, int revents) |
|
|
954 | \& { |
|
|
955 | \& struct my_biggy big = (struct my_biggy * |
|
|
956 | \& (((char *)w) - offsetof (struct my_biggy, t2)); |
|
|
957 | \& } |
|
|
958 | .Ve |
643 | .SH "WATCHER TYPES" |
959 | .SH "WATCHER TYPES" |
644 | .IX Header "WATCHER TYPES" |
960 | .IX Header "WATCHER TYPES" |
645 | This section describes each watcher in detail, but will not repeat |
961 | This section describes each watcher in detail, but will not repeat |
646 | information given in the last section. |
962 | information given in the last section. Any initialisation/set macros, |
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963 | functions and members specific to the watcher type are explained. |
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964 | .PP |
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965 | Members are additionally marked with either \fI[read\-only]\fR, meaning that, |
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966 | while the watcher is active, you can look at the member and expect some |
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967 | sensible content, but you must not modify it (you can modify it while the |
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968 | watcher is stopped to your hearts content), or \fI[read\-write]\fR, which |
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969 | means you can expect it to have some sensible content while the watcher |
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970 | is active, but you can also modify it. Modifying it may not do something |
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971 | sensible or take immediate effect (or do anything at all), but libev will |
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972 | not crash or malfunction in any way. |
647 | .ie n .Sh """ev_io"" \- is this file descriptor readable or writable" |
973 | .ie n .Sh """ev_io"" \- is this file descriptor readable or writable?" |
648 | .el .Sh "\f(CWev_io\fP \- is this file descriptor readable or writable" |
974 | .el .Sh "\f(CWev_io\fP \- is this file descriptor readable or writable?" |
649 | .IX Subsection "ev_io - is this file descriptor readable or writable" |
975 | .IX Subsection "ev_io - is this file descriptor readable or writable?" |
650 | I/O watchers check whether a file descriptor is readable or writable |
976 | I/O watchers check whether a file descriptor is readable or writable |
651 | in each iteration of the event loop (This behaviour is called |
977 | in each iteration of the event loop, or, more precisely, when reading |
652 | level-triggering because you keep receiving events as long as the |
978 | would not block the process and writing would at least be able to write |
653 | condition persists. Remember you can stop the watcher if you don't want to |
979 | some data. This behaviour is called level-triggering because you keep |
654 | act on the event and neither want to receive future events). |
980 | receiving events as long as the condition persists. Remember you can stop |
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981 | the watcher if you don't want to act on the event and neither want to |
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982 | receive future events. |
655 | .PP |
983 | .PP |
656 | In general you can register as many read and/or write event watchers per |
984 | In general you can register as many read and/or write event watchers per |
657 | fd as you want (as long as you don't confuse yourself). Setting all file |
985 | fd as you want (as long as you don't confuse yourself). Setting all file |
658 | descriptors to non-blocking mode is also usually a good idea (but not |
986 | descriptors to non-blocking mode is also usually a good idea (but not |
659 | required if you know what you are doing). |
987 | required if you know what you are doing). |
660 | .PP |
988 | .PP |
661 | You have to be careful with dup'ed file descriptors, though. Some backends |
989 | You have to be careful with dup'ed file descriptors, though. Some backends |
662 | (the linux epoll backend is a notable example) cannot handle dup'ed file |
990 | (the linux epoll backend is a notable example) cannot handle dup'ed file |
663 | descriptors correctly if you register interest in two or more fds pointing |
991 | descriptors correctly if you register interest in two or more fds pointing |
664 | to the same underlying file/socket etc. description (that is, they share |
992 | to the same underlying file/socket/etc. description (that is, they share |
665 | the same underlying \*(L"file open\*(R"). |
993 | the same underlying \*(L"file open\*(R"). |
666 | .PP |
994 | .PP |
667 | If you must do this, then force the use of a known-to-be-good backend |
995 | If you must do this, then force the use of a known-to-be-good backend |
668 | (at the time of this writing, this includes only \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR and |
996 | (at the time of this writing, this includes only \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR and |
669 | \&\f(CW\*(C`EVBACKEND_POLL\*(C'\fR). |
997 | \&\f(CW\*(C`EVBACKEND_POLL\*(C'\fR). |
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998 | .PP |
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999 | Another thing you have to watch out for is that it is quite easy to |
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1000 | receive \*(L"spurious\*(R" readyness notifications, that is your callback might |
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1001 | be called with \f(CW\*(C`EV_READ\*(C'\fR but a subsequent \f(CW\*(C`read\*(C'\fR(2) will actually block |
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1002 | because there is no data. Not only are some backends known to create a |
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1003 | lot of those (for example solaris ports), it is very easy to get into |
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1004 | this situation even with a relatively standard program structure. Thus |
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1005 | it is best to always use non-blocking I/O: An extra \f(CW\*(C`read\*(C'\fR(2) returning |
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1006 | \&\f(CW\*(C`EAGAIN\*(C'\fR is far preferable to a program hanging until some data arrives. |
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1007 | .PP |
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1008 | If you cannot run the fd in non-blocking mode (for example you should not |
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1009 | play around with an Xlib connection), then you have to seperately re-test |
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1010 | wether a file descriptor is really ready with a known-to-be good interface |
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1011 | such as poll (fortunately in our Xlib example, Xlib already does this on |
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1012 | its own, so its quite safe to use). |
670 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
1013 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
671 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
1014 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
672 | .PD 0 |
1015 | .PD 0 |
673 | .IP "ev_io_set (ev_io *, int fd, int events)" 4 |
1016 | .IP "ev_io_set (ev_io *, int fd, int events)" 4 |
674 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
1017 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
675 | .PD |
1018 | .PD |
676 | Configures an \f(CW\*(C`ev_io\*(C'\fR watcher. The fd is the file descriptor to rceeive |
1019 | Configures an \f(CW\*(C`ev_io\*(C'\fR watcher. The \f(CW\*(C`fd\*(C'\fR is the file descriptor to |
677 | 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 | |
1020 | rceeive events for and events is either \f(CW\*(C`EV_READ\*(C'\fR, \f(CW\*(C`EV_WRITE\*(C'\fR or |
678 | EV_WRITE\*(C'\fR to receive the given events. |
1021 | \&\f(CW\*(C`EV_READ | EV_WRITE\*(C'\fR to receive the given events. |
679 | .Sp |
1022 | .IP "int fd [read\-only]" 4 |
680 | Please note that most of the more scalable backend mechanisms (for example |
1023 | .IX Item "int fd [read-only]" |
681 | epoll and solaris ports) can result in spurious readyness notifications |
1024 | The file descriptor being watched. |
682 | for file descriptors, so you practically need to use non-blocking I/O (and |
1025 | .IP "int events [read\-only]" 4 |
683 | treat callback invocation as hint only), or retest separately with a safe |
1026 | .IX Item "int events [read-only]" |
684 | interface before doing I/O (XLib can do this), or force the use of either |
1027 | The events being watched. |
685 | \&\f(CW\*(C`EVBACKEND_SELECT\*(C'\fR or \f(CW\*(C`EVBACKEND_POLL\*(C'\fR, which don't suffer from this |
1028 | .PP |
686 | problem. Also note that it is quite easy to have your callback invoked |
1029 | Example: Call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well |
687 | when the readyness condition is no longer valid even when employing |
1030 | readable, but only once. Since it is likely line\-buffered, you could |
688 | typical ways of handling events, so its a good idea to use non-blocking |
1031 | attempt to read a whole line in the callback. |
689 | I/O unconditionally. |
1032 | .PP |
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1033 | .Vb 6 |
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1034 | \& static void |
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1035 | \& stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
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1036 | \& { |
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1037 | \& ev_io_stop (loop, w); |
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1038 | \& .. read from stdin here (or from w->fd) and haqndle any I/O errors |
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1039 | \& } |
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1040 | .Ve |
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1041 | .PP |
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1042 | .Vb 6 |
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1043 | \& ... |
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1044 | \& struct ev_loop *loop = ev_default_init (0); |
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1045 | \& struct ev_io stdin_readable; |
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1046 | \& ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ); |
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1047 | \& ev_io_start (loop, &stdin_readable); |
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1048 | \& ev_loop (loop, 0); |
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1049 | .Ve |
690 | .ie n .Sh """ev_timer"" \- relative and optionally recurring timeouts" |
1050 | .ie n .Sh """ev_timer"" \- relative and optionally repeating timeouts" |
691 | .el .Sh "\f(CWev_timer\fP \- relative and optionally recurring timeouts" |
1051 | .el .Sh "\f(CWev_timer\fP \- relative and optionally repeating timeouts" |
692 | .IX Subsection "ev_timer - relative and optionally recurring timeouts" |
1052 | .IX Subsection "ev_timer - relative and optionally repeating timeouts" |
693 | Timer watchers are simple relative timers that generate an event after a |
1053 | Timer watchers are simple relative timers that generate an event after a |
694 | given time, and optionally repeating in regular intervals after that. |
1054 | given time, and optionally repeating in regular intervals after that. |
695 | .PP |
1055 | .PP |
696 | The timers are based on real time, that is, if you register an event that |
1056 | The timers are based on real time, that is, if you register an event that |
697 | times out after an hour and you reset your system clock to last years |
1057 | times out after an hour and you reset your system clock to last years |
… | |
… | |
731 | .IP "ev_timer_again (loop)" 4 |
1091 | .IP "ev_timer_again (loop)" 4 |
732 | .IX Item "ev_timer_again (loop)" |
1092 | .IX Item "ev_timer_again (loop)" |
733 | This will act as if the timer timed out and restart it again if it is |
1093 | This will act as if the timer timed out and restart it again if it is |
734 | repeating. The exact semantics are: |
1094 | repeating. The exact semantics are: |
735 | .Sp |
1095 | .Sp |
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1096 | If the timer is pending, its pending status is cleared. |
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1097 | .Sp |
736 | If the timer is started but nonrepeating, stop it. |
1098 | If the timer is started but nonrepeating, stop it (as if it timed out). |
737 | .Sp |
1099 | .Sp |
738 | If the timer is repeating, either start it if necessary (with the repeat |
1100 | If the timer is repeating, either start it if necessary (with the |
739 | value), or reset the running timer to the repeat value. |
1101 | \&\f(CW\*(C`repeat\*(C'\fR value), or reset the running timer to the \f(CW\*(C`repeat\*(C'\fR value. |
740 | .Sp |
1102 | .Sp |
741 | This sounds a bit complicated, but here is a useful and typical |
1103 | This sounds a bit complicated, but here is a useful and typical |
742 | example: Imagine you have a tcp connection and you want a so-called idle |
1104 | example: Imagine you have a tcp connection and you want a so-called idle |
743 | timeout, that is, you want to be called when there have been, say, 60 |
1105 | timeout, that is, you want to be called when there have been, say, 60 |
744 | seconds of inactivity on the socket. The easiest way to do this is to |
1106 | seconds of inactivity on the socket. The easiest way to do this is to |
745 | configure an \f(CW\*(C`ev_timer\*(C'\fR with after=repeat=60 and calling ev_timer_again each |
1107 | configure an \f(CW\*(C`ev_timer\*(C'\fR with a \f(CW\*(C`repeat\*(C'\fR value of \f(CW60\fR and then call |
746 | time you successfully read or write some data. If you go into an idle |
1108 | \&\f(CW\*(C`ev_timer_again\*(C'\fR each time you successfully read or write some data. If |
747 | state where you do not expect data to travel on the socket, you can stop |
1109 | you go into an idle state where you do not expect data to travel on the |
748 | the timer, and again will automatically restart it if need be. |
1110 | socket, you can \f(CW\*(C`ev_timer_stop\*(C'\fR the timer, and \f(CW\*(C`ev_timer_again\*(C'\fR will |
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1111 | automatically restart it if need be. |
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1112 | .Sp |
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1113 | That means you can ignore the \f(CW\*(C`after\*(C'\fR value and \f(CW\*(C`ev_timer_start\*(C'\fR |
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1114 | altogether and only ever use the \f(CW\*(C`repeat\*(C'\fR value and \f(CW\*(C`ev_timer_again\*(C'\fR: |
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1115 | .Sp |
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1116 | .Vb 8 |
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1117 | \& ev_timer_init (timer, callback, 0., 5.); |
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1118 | \& ev_timer_again (loop, timer); |
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1119 | \& ... |
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1120 | \& timer->again = 17.; |
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1121 | \& ev_timer_again (loop, timer); |
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1122 | \& ... |
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1123 | \& timer->again = 10.; |
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1124 | \& ev_timer_again (loop, timer); |
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1125 | .Ve |
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1126 | .Sp |
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1127 | This is more slightly efficient then stopping/starting the timer each time |
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1128 | you want to modify its timeout value. |
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1129 | .IP "ev_tstamp repeat [read\-write]" 4 |
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1130 | .IX Item "ev_tstamp repeat [read-write]" |
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1131 | The current \f(CW\*(C`repeat\*(C'\fR value. Will be used each time the watcher times out |
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1132 | or \f(CW\*(C`ev_timer_again\*(C'\fR is called and determines the next timeout (if any), |
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1133 | which is also when any modifications are taken into account. |
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1134 | .PP |
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1135 | Example: Create a timer that fires after 60 seconds. |
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1136 | .PP |
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1137 | .Vb 5 |
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1138 | \& static void |
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1139 | \& one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
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1140 | \& { |
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1141 | \& .. one minute over, w is actually stopped right here |
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1142 | \& } |
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1143 | .Ve |
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1144 | .PP |
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1145 | .Vb 3 |
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1146 | \& struct ev_timer mytimer; |
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1147 | \& ev_timer_init (&mytimer, one_minute_cb, 60., 0.); |
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1148 | \& ev_timer_start (loop, &mytimer); |
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1149 | .Ve |
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1150 | .PP |
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1151 | Example: Create a timeout timer that times out after 10 seconds of |
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1152 | inactivity. |
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1153 | .PP |
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1154 | .Vb 5 |
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1155 | \& static void |
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1156 | \& timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
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1157 | \& { |
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1158 | \& .. ten seconds without any activity |
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1159 | \& } |
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1160 | .Ve |
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1161 | .PP |
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1162 | .Vb 4 |
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1163 | \& struct ev_timer mytimer; |
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1164 | \& ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */ |
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1165 | \& ev_timer_again (&mytimer); /* start timer */ |
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1166 | \& ev_loop (loop, 0); |
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1167 | .Ve |
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1168 | .PP |
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1169 | .Vb 3 |
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1170 | \& // and in some piece of code that gets executed on any "activity": |
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1171 | \& // reset the timeout to start ticking again at 10 seconds |
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1172 | \& ev_timer_again (&mytimer); |
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1173 | .Ve |
749 | .ie n .Sh """ev_periodic"" \- to cron or not to cron" |
1174 | .ie n .Sh """ev_periodic"" \- to cron or not to cron?" |
750 | .el .Sh "\f(CWev_periodic\fP \- to cron or not to cron" |
1175 | .el .Sh "\f(CWev_periodic\fP \- to cron or not to cron?" |
751 | .IX Subsection "ev_periodic - to cron or not to cron" |
1176 | .IX Subsection "ev_periodic - to cron or not to cron?" |
752 | Periodic watchers are also timers of a kind, but they are very versatile |
1177 | Periodic watchers are also timers of a kind, but they are very versatile |
753 | (and unfortunately a bit complex). |
1178 | (and unfortunately a bit complex). |
754 | .PP |
1179 | .PP |
755 | Unlike \f(CW\*(C`ev_timer\*(C'\fR's, they are not based on real time (or relative time) |
1180 | Unlike \f(CW\*(C`ev_timer\*(C'\fR's, they are not based on real time (or relative time) |
756 | but on wallclock time (absolute time). You can tell a periodic watcher |
1181 | but on wallclock time (absolute time). You can tell a periodic watcher |
757 | to trigger \*(L"at\*(R" some specific point in time. For example, if you tell a |
1182 | to trigger \*(L"at\*(R" some specific point in time. For example, if you tell a |
758 | periodic watcher to trigger in 10 seconds (by specifiying e.g. c<ev_now () |
1183 | periodic watcher to trigger in 10 seconds (by specifiying e.g. \f(CW\*(C`ev_now () |
759 | + 10.>) and then reset your system clock to the last year, then it will |
1184 | + 10.\*(C'\fR) and then reset your system clock to the last year, then it will |
760 | take a year to trigger the event (unlike an \f(CW\*(C`ev_timer\*(C'\fR, which would trigger |
1185 | take a year to trigger the event (unlike an \f(CW\*(C`ev_timer\*(C'\fR, which would trigger |
761 | roughly 10 seconds later and of course not if you reset your system time |
1186 | roughly 10 seconds later and of course not if you reset your system time |
762 | again). |
1187 | again). |
763 | .PP |
1188 | .PP |
764 | They can also be used to implement vastly more complex timers, such as |
1189 | They can also be used to implement vastly more complex timers, such as |
… | |
… | |
845 | .IX Item "ev_periodic_again (loop, ev_periodic *)" |
1270 | .IX Item "ev_periodic_again (loop, ev_periodic *)" |
846 | Simply stops and restarts the periodic watcher again. This is only useful |
1271 | Simply stops and restarts the periodic watcher again. This is only useful |
847 | when you changed some parameters or the reschedule callback would return |
1272 | when you changed some parameters or the reschedule callback would return |
848 | a different time than the last time it was called (e.g. in a crond like |
1273 | a different time than the last time it was called (e.g. in a crond like |
849 | program when the crontabs have changed). |
1274 | program when the crontabs have changed). |
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1275 | .IP "ev_tstamp interval [read\-write]" 4 |
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1276 | .IX Item "ev_tstamp interval [read-write]" |
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1277 | The current interval value. Can be modified any time, but changes only |
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1278 | take effect when the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being |
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1279 | called. |
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1280 | .IP "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read\-write]" 4 |
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1281 | .IX Item "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write]" |
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1282 | The current reschedule callback, or \f(CW0\fR, if this functionality is |
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1283 | switched off. Can be changed any time, but changes only take effect when |
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1284 | the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called. |
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1285 | .PP |
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1286 | Example: Call a callback every hour, or, more precisely, whenever the |
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1287 | system clock is divisible by 3600. The callback invocation times have |
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1288 | potentially a lot of jittering, but good long-term stability. |
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1289 | .PP |
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1290 | .Vb 5 |
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1291 | \& static void |
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1292 | \& clock_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
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1293 | \& { |
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1294 | \& ... its now a full hour (UTC, or TAI or whatever your clock follows) |
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1295 | \& } |
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1296 | .Ve |
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1297 | .PP |
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1298 | .Vb 3 |
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1299 | \& struct ev_periodic hourly_tick; |
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1300 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); |
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1301 | \& ev_periodic_start (loop, &hourly_tick); |
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1302 | .Ve |
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1303 | .PP |
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1304 | Example: The same as above, but use a reschedule callback to do it: |
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1305 | .PP |
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1306 | .Vb 1 |
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1307 | \& #include <math.h> |
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1308 | .Ve |
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1309 | .PP |
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1310 | .Vb 5 |
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1311 | \& static ev_tstamp |
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1312 | \& my_scheduler_cb (struct ev_periodic *w, ev_tstamp now) |
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1313 | \& { |
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1314 | \& return fmod (now, 3600.) + 3600.; |
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1315 | \& } |
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1316 | .Ve |
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1317 | .PP |
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1318 | .Vb 1 |
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1319 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); |
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1320 | .Ve |
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1321 | .PP |
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1322 | Example: Call a callback every hour, starting now: |
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1323 | .PP |
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1324 | .Vb 4 |
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1325 | \& struct ev_periodic hourly_tick; |
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1326 | \& ev_periodic_init (&hourly_tick, clock_cb, |
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1327 | \& fmod (ev_now (loop), 3600.), 3600., 0); |
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1328 | \& ev_periodic_start (loop, &hourly_tick); |
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1329 | .Ve |
850 | .ie n .Sh """ev_signal"" \- signal me when a signal gets signalled" |
1330 | .ie n .Sh """ev_signal"" \- signal me when a signal gets signalled!" |
851 | .el .Sh "\f(CWev_signal\fP \- signal me when a signal gets signalled" |
1331 | .el .Sh "\f(CWev_signal\fP \- signal me when a signal gets signalled!" |
852 | .IX Subsection "ev_signal - signal me when a signal gets signalled" |
1332 | .IX Subsection "ev_signal - signal me when a signal gets signalled!" |
853 | Signal watchers will trigger an event when the process receives a specific |
1333 | Signal watchers will trigger an event when the process receives a specific |
854 | signal one or more times. Even though signals are very asynchronous, libev |
1334 | signal one or more times. Even though signals are very asynchronous, libev |
855 | will try it's best to deliver signals synchronously, i.e. as part of the |
1335 | will try it's best to deliver signals synchronously, i.e. as part of the |
856 | normal event processing, like any other event. |
1336 | normal event processing, like any other event. |
857 | .PP |
1337 | .PP |
… | |
… | |
867 | .IP "ev_signal_set (ev_signal *, int signum)" 4 |
1347 | .IP "ev_signal_set (ev_signal *, int signum)" 4 |
868 | .IX Item "ev_signal_set (ev_signal *, int signum)" |
1348 | .IX Item "ev_signal_set (ev_signal *, int signum)" |
869 | .PD |
1349 | .PD |
870 | Configures the watcher to trigger on the given signal number (usually one |
1350 | Configures the watcher to trigger on the given signal number (usually one |
871 | of the \f(CW\*(C`SIGxxx\*(C'\fR constants). |
1351 | of the \f(CW\*(C`SIGxxx\*(C'\fR constants). |
|
|
1352 | .IP "int signum [read\-only]" 4 |
|
|
1353 | .IX Item "int signum [read-only]" |
|
|
1354 | The signal the watcher watches out for. |
872 | .ie n .Sh """ev_child"" \- wait for pid status changes" |
1355 | .ie n .Sh """ev_child"" \- watch out for process status changes" |
873 | .el .Sh "\f(CWev_child\fP \- wait for pid status changes" |
1356 | .el .Sh "\f(CWev_child\fP \- watch out for process status changes" |
874 | .IX Subsection "ev_child - wait for pid status changes" |
1357 | .IX Subsection "ev_child - watch out for process status changes" |
875 | Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to |
1358 | Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to |
876 | some child status changes (most typically when a child of yours dies). |
1359 | some child status changes (most typically when a child of yours dies). |
877 | .IP "ev_child_init (ev_child *, callback, int pid)" 4 |
1360 | .IP "ev_child_init (ev_child *, callback, int pid)" 4 |
878 | .IX Item "ev_child_init (ev_child *, callback, int pid)" |
1361 | .IX Item "ev_child_init (ev_child *, callback, int pid)" |
879 | .PD 0 |
1362 | .PD 0 |
… | |
… | |
884 | \&\fIany\fR process if \f(CW\*(C`pid\*(C'\fR is specified as \f(CW0\fR). The callback can look |
1367 | \&\fIany\fR process if \f(CW\*(C`pid\*(C'\fR is specified as \f(CW0\fR). The callback can look |
885 | at the \f(CW\*(C`rstatus\*(C'\fR member of the \f(CW\*(C`ev_child\*(C'\fR watcher structure to see |
1368 | at the \f(CW\*(C`rstatus\*(C'\fR member of the \f(CW\*(C`ev_child\*(C'\fR watcher structure to see |
886 | the status word (use the macros from \f(CW\*(C`sys/wait.h\*(C'\fR and see your systems |
1369 | the status word (use the macros from \f(CW\*(C`sys/wait.h\*(C'\fR and see your systems |
887 | \&\f(CW\*(C`waitpid\*(C'\fR documentation). The \f(CW\*(C`rpid\*(C'\fR member contains the pid of the |
1370 | \&\f(CW\*(C`waitpid\*(C'\fR documentation). The \f(CW\*(C`rpid\*(C'\fR member contains the pid of the |
888 | process causing the status change. |
1371 | process causing the status change. |
|
|
1372 | .IP "int pid [read\-only]" 4 |
|
|
1373 | .IX Item "int pid [read-only]" |
|
|
1374 | The process id this watcher watches out for, or \f(CW0\fR, meaning any process id. |
|
|
1375 | .IP "int rpid [read\-write]" 4 |
|
|
1376 | .IX Item "int rpid [read-write]" |
|
|
1377 | The process id that detected a status change. |
|
|
1378 | .IP "int rstatus [read\-write]" 4 |
|
|
1379 | .IX Item "int rstatus [read-write]" |
|
|
1380 | The process exit/trace status caused by \f(CW\*(C`rpid\*(C'\fR (see your systems |
|
|
1381 | \&\f(CW\*(C`waitpid\*(C'\fR and \f(CW\*(C`sys/wait.h\*(C'\fR documentation for details). |
|
|
1382 | .PP |
|
|
1383 | Example: Try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0. |
|
|
1384 | .PP |
|
|
1385 | .Vb 5 |
|
|
1386 | \& static void |
|
|
1387 | \& sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
|
|
1388 | \& { |
|
|
1389 | \& ev_unloop (loop, EVUNLOOP_ALL); |
|
|
1390 | \& } |
|
|
1391 | .Ve |
|
|
1392 | .PP |
|
|
1393 | .Vb 3 |
|
|
1394 | \& struct ev_signal signal_watcher; |
|
|
1395 | \& ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
|
|
1396 | \& ev_signal_start (loop, &sigint_cb); |
|
|
1397 | .Ve |
|
|
1398 | .ie n .Sh """ev_stat"" \- did the file attributes just change?" |
|
|
1399 | .el .Sh "\f(CWev_stat\fP \- did the file attributes just change?" |
|
|
1400 | .IX Subsection "ev_stat - did the file attributes just change?" |
|
|
1401 | This watches a filesystem path for attribute changes. That is, it calls |
|
|
1402 | \&\f(CW\*(C`stat\*(C'\fR regularly (or when the \s-1OS\s0 says it changed) and sees if it changed |
|
|
1403 | compared to the last time, invoking the callback if it did. |
|
|
1404 | .PP |
|
|
1405 | The path does not need to exist: changing from \*(L"path exists\*(R" to \*(L"path does |
|
|
1406 | not exist\*(R" is a status change like any other. The condition \*(L"path does |
|
|
1407 | not exist\*(R" is signified by the \f(CW\*(C`st_nlink\*(C'\fR field being zero (which is |
|
|
1408 | otherwise always forced to be at least one) and all the other fields of |
|
|
1409 | the stat buffer having unspecified contents. |
|
|
1410 | .PP |
|
|
1411 | The path \fIshould\fR be absolute and \fImust not\fR end in a slash. If it is |
|
|
1412 | relative and your working directory changes, the behaviour is undefined. |
|
|
1413 | .PP |
|
|
1414 | Since there is no standard to do this, the portable implementation simply |
|
|
1415 | calls \f(CW\*(C`stat (2)\*(C'\fR regularly on the path to see if it changed somehow. You |
|
|
1416 | can specify a recommended polling interval for this case. If you specify |
|
|
1417 | a polling interval of \f(CW0\fR (highly recommended!) then a \fIsuitable, |
|
|
1418 | unspecified default\fR value will be used (which you can expect to be around |
|
|
1419 | five seconds, although this might change dynamically). Libev will also |
|
|
1420 | impose a minimum interval which is currently around \f(CW0.1\fR, but thats |
|
|
1421 | usually overkill. |
|
|
1422 | .PP |
|
|
1423 | This watcher type is not meant for massive numbers of stat watchers, |
|
|
1424 | as even with OS-supported change notifications, this can be |
|
|
1425 | resource\-intensive. |
|
|
1426 | .PP |
|
|
1427 | At the time of this writing, only the Linux inotify interface is |
|
|
1428 | implemented (implementing kqueue support is left as an exercise for the |
|
|
1429 | reader). Inotify will be used to give hints only and should not change the |
|
|
1430 | semantics of \f(CW\*(C`ev_stat\*(C'\fR watchers, which means that libev sometimes needs |
|
|
1431 | to fall back to regular polling again even with inotify, but changes are |
|
|
1432 | usually detected immediately, and if the file exists there will be no |
|
|
1433 | polling. |
|
|
1434 | .IP "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" 4 |
|
|
1435 | .IX Item "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" |
|
|
1436 | .PD 0 |
|
|
1437 | .IP "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" 4 |
|
|
1438 | .IX Item "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" |
|
|
1439 | .PD |
|
|
1440 | Configures the watcher to wait for status changes of the given |
|
|
1441 | \&\f(CW\*(C`path\*(C'\fR. The \f(CW\*(C`interval\*(C'\fR is a hint on how quickly a change is expected to |
|
|
1442 | be detected and should normally be specified as \f(CW0\fR to let libev choose |
|
|
1443 | a suitable value. The memory pointed to by \f(CW\*(C`path\*(C'\fR must point to the same |
|
|
1444 | path for as long as the watcher is active. |
|
|
1445 | .Sp |
|
|
1446 | The callback will be receive \f(CW\*(C`EV_STAT\*(C'\fR when a change was detected, |
|
|
1447 | relative to the attributes at the time the watcher was started (or the |
|
|
1448 | last change was detected). |
|
|
1449 | .IP "ev_stat_stat (ev_stat *)" 4 |
|
|
1450 | .IX Item "ev_stat_stat (ev_stat *)" |
|
|
1451 | Updates the stat buffer immediately with new values. If you change the |
|
|
1452 | watched path in your callback, you could call this fucntion to avoid |
|
|
1453 | detecting this change (while introducing a race condition). Can also be |
|
|
1454 | useful simply to find out the new values. |
|
|
1455 | .IP "ev_statdata attr [read\-only]" 4 |
|
|
1456 | .IX Item "ev_statdata attr [read-only]" |
|
|
1457 | The most-recently detected attributes of the file. Although the type is of |
|
|
1458 | \&\f(CW\*(C`ev_statdata\*(C'\fR, this is usually the (or one of the) \f(CW\*(C`struct stat\*(C'\fR types |
|
|
1459 | suitable for your system. If the \f(CW\*(C`st_nlink\*(C'\fR member is \f(CW0\fR, then there |
|
|
1460 | was some error while \f(CW\*(C`stat\*(C'\fRing the file. |
|
|
1461 | .IP "ev_statdata prev [read\-only]" 4 |
|
|
1462 | .IX Item "ev_statdata prev [read-only]" |
|
|
1463 | The previous attributes of the file. The callback gets invoked whenever |
|
|
1464 | \&\f(CW\*(C`prev\*(C'\fR != \f(CW\*(C`attr\*(C'\fR. |
|
|
1465 | .IP "ev_tstamp interval [read\-only]" 4 |
|
|
1466 | .IX Item "ev_tstamp interval [read-only]" |
|
|
1467 | The specified interval. |
|
|
1468 | .IP "const char *path [read\-only]" 4 |
|
|
1469 | .IX Item "const char *path [read-only]" |
|
|
1470 | The filesystem path that is being watched. |
|
|
1471 | .PP |
|
|
1472 | Example: Watch \f(CW\*(C`/etc/passwd\*(C'\fR for attribute changes. |
|
|
1473 | .PP |
|
|
1474 | .Vb 15 |
|
|
1475 | \& static void |
|
|
1476 | \& passwd_cb (struct ev_loop *loop, ev_stat *w, int revents) |
|
|
1477 | \& { |
|
|
1478 | \& /* /etc/passwd changed in some way */ |
|
|
1479 | \& if (w->attr.st_nlink) |
|
|
1480 | \& { |
|
|
1481 | \& printf ("passwd current size %ld\en", (long)w->attr.st_size); |
|
|
1482 | \& printf ("passwd current atime %ld\en", (long)w->attr.st_mtime); |
|
|
1483 | \& printf ("passwd current mtime %ld\en", (long)w->attr.st_mtime); |
|
|
1484 | \& } |
|
|
1485 | \& else |
|
|
1486 | \& /* you shalt not abuse printf for puts */ |
|
|
1487 | \& puts ("wow, /etc/passwd is not there, expect problems. " |
|
|
1488 | \& "if this is windows, they already arrived\en"); |
|
|
1489 | \& } |
|
|
1490 | .Ve |
|
|
1491 | .PP |
|
|
1492 | .Vb 2 |
|
|
1493 | \& ... |
|
|
1494 | \& ev_stat passwd; |
|
|
1495 | .Ve |
|
|
1496 | .PP |
|
|
1497 | .Vb 2 |
|
|
1498 | \& ev_stat_init (&passwd, passwd_cb, "/etc/passwd"); |
|
|
1499 | \& ev_stat_start (loop, &passwd); |
|
|
1500 | .Ve |
889 | .ie n .Sh """ev_idle"" \- when you've got nothing better to do" |
1501 | .ie n .Sh """ev_idle"" \- when you've got nothing better to do..." |
890 | .el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do" |
1502 | .el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do..." |
891 | .IX Subsection "ev_idle - when you've got nothing better to do" |
1503 | .IX Subsection "ev_idle - when you've got nothing better to do..." |
892 | Idle watchers trigger events when there are no other events are pending |
1504 | Idle watchers trigger events when there are no other events are pending |
893 | (prepare, check and other idle watchers do not count). That is, as long |
1505 | (prepare, check and other idle watchers do not count). That is, as long |
894 | as your process is busy handling sockets or timeouts (or even signals, |
1506 | as your process is busy handling sockets or timeouts (or even signals, |
895 | imagine) it will not be triggered. But when your process is idle all idle |
1507 | imagine) it will not be triggered. But when your process is idle all idle |
896 | watchers are being called again and again, once per event loop iteration \- |
1508 | watchers are being called again and again, once per event loop iteration \- |
… | |
… | |
907 | .IP "ev_idle_init (ev_signal *, callback)" 4 |
1519 | .IP "ev_idle_init (ev_signal *, callback)" 4 |
908 | .IX Item "ev_idle_init (ev_signal *, callback)" |
1520 | .IX Item "ev_idle_init (ev_signal *, callback)" |
909 | Initialises and configures the idle watcher \- it has no parameters of any |
1521 | Initialises and configures the idle watcher \- it has no parameters of any |
910 | kind. There is a \f(CW\*(C`ev_idle_set\*(C'\fR macro, but using it is utterly pointless, |
1522 | kind. There is a \f(CW\*(C`ev_idle_set\*(C'\fR macro, but using it is utterly pointless, |
911 | believe me. |
1523 | believe me. |
|
|
1524 | .PP |
|
|
1525 | Example: Dynamically allocate an \f(CW\*(C`ev_idle\*(C'\fR watcher, start it, and in the |
|
|
1526 | callback, free it. Also, use no error checking, as usual. |
|
|
1527 | .PP |
|
|
1528 | .Vb 7 |
|
|
1529 | \& static void |
|
|
1530 | \& idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
|
|
1531 | \& { |
|
|
1532 | \& free (w); |
|
|
1533 | \& // now do something you wanted to do when the program has |
|
|
1534 | \& // no longer asnything immediate to do. |
|
|
1535 | \& } |
|
|
1536 | .Ve |
|
|
1537 | .PP |
|
|
1538 | .Vb 3 |
|
|
1539 | \& struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle)); |
|
|
1540 | \& ev_idle_init (idle_watcher, idle_cb); |
|
|
1541 | \& ev_idle_start (loop, idle_cb); |
|
|
1542 | .Ve |
912 | .ie n .Sh """ev_prepare""\fP and \f(CW""ev_check"" \- customise your event loop" |
1543 | .ie n .Sh """ev_prepare""\fP and \f(CW""ev_check"" \- customise your event loop!" |
913 | .el .Sh "\f(CWev_prepare\fP and \f(CWev_check\fP \- customise your event loop" |
1544 | .el .Sh "\f(CWev_prepare\fP and \f(CWev_check\fP \- customise your event loop!" |
914 | .IX Subsection "ev_prepare and ev_check - customise your event loop" |
1545 | .IX Subsection "ev_prepare and ev_check - customise your event loop!" |
915 | Prepare and check watchers are usually (but not always) used in tandem: |
1546 | Prepare and check watchers are usually (but not always) used in tandem: |
916 | prepare watchers get invoked before the process blocks and check watchers |
1547 | prepare watchers get invoked before the process blocks and check watchers |
917 | afterwards. |
1548 | afterwards. |
918 | .PP |
1549 | .PP |
|
|
1550 | You \fImust not\fR call \f(CW\*(C`ev_loop\*(C'\fR or similar functions that enter |
|
|
1551 | the current event loop from either \f(CW\*(C`ev_prepare\*(C'\fR or \f(CW\*(C`ev_check\*(C'\fR |
|
|
1552 | watchers. Other loops than the current one are fine, however. The |
|
|
1553 | rationale behind this is that you do not need to check for recursion in |
|
|
1554 | those watchers, i.e. the sequence will always be \f(CW\*(C`ev_prepare\*(C'\fR, blocking, |
|
|
1555 | \&\f(CW\*(C`ev_check\*(C'\fR so if you have one watcher of each kind they will always be |
|
|
1556 | called in pairs bracketing the blocking call. |
|
|
1557 | .PP |
919 | Their main purpose is to integrate other event mechanisms into libev. This |
1558 | Their main purpose is to integrate other event mechanisms into libev and |
920 | could be used, for example, to track variable changes, implement your own |
1559 | their use is somewhat advanced. This could be used, for example, to track |
921 | watchers, integrate net-snmp or a coroutine library and lots more. |
1560 | variable changes, implement your own watchers, integrate net-snmp or a |
|
|
1561 | coroutine library and lots more. They are also occasionally useful if |
|
|
1562 | you cache some data and want to flush it before blocking (for example, |
|
|
1563 | in X programs you might want to do an \f(CW\*(C`XFlush ()\*(C'\fR in an \f(CW\*(C`ev_prepare\*(C'\fR |
|
|
1564 | watcher). |
922 | .PP |
1565 | .PP |
923 | This is done by examining in each prepare call which file descriptors need |
1566 | This is done by examining in each prepare call which file descriptors need |
924 | to be watched by the other library, registering \f(CW\*(C`ev_io\*(C'\fR watchers for |
1567 | to be watched by the other library, registering \f(CW\*(C`ev_io\*(C'\fR watchers for |
925 | them and starting an \f(CW\*(C`ev_timer\*(C'\fR watcher for any timeouts (many libraries |
1568 | them and starting an \f(CW\*(C`ev_timer\*(C'\fR watcher for any timeouts (many libraries |
926 | provide just this functionality). Then, in the check watcher you check for |
1569 | provide just this functionality). Then, in the check watcher you check for |
… | |
… | |
944 | .IX Item "ev_check_init (ev_check *, callback)" |
1587 | .IX Item "ev_check_init (ev_check *, callback)" |
945 | .PD |
1588 | .PD |
946 | Initialises and configures the prepare or check watcher \- they have no |
1589 | Initialises and configures the prepare or check watcher \- they have no |
947 | parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR |
1590 | parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR |
948 | macros, but using them is utterly, utterly and completely pointless. |
1591 | macros, but using them is utterly, utterly and completely pointless. |
|
|
1592 | .PP |
|
|
1593 | Example: To include a library such as adns, you would add \s-1IO\s0 watchers |
|
|
1594 | and a timeout watcher in a prepare handler, as required by libadns, and |
|
|
1595 | in a check watcher, destroy them and call into libadns. What follows is |
|
|
1596 | pseudo-code only of course: |
|
|
1597 | .PP |
|
|
1598 | .Vb 2 |
|
|
1599 | \& static ev_io iow [nfd]; |
|
|
1600 | \& static ev_timer tw; |
|
|
1601 | .Ve |
|
|
1602 | .PP |
|
|
1603 | .Vb 9 |
|
|
1604 | \& static void |
|
|
1605 | \& io_cb (ev_loop *loop, ev_io *w, int revents) |
|
|
1606 | \& { |
|
|
1607 | \& // set the relevant poll flags |
|
|
1608 | \& // could also call adns_processreadable etc. here |
|
|
1609 | \& struct pollfd *fd = (struct pollfd *)w->data; |
|
|
1610 | \& if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
|
|
1611 | \& if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
|
|
1612 | \& } |
|
|
1613 | .Ve |
|
|
1614 | .PP |
|
|
1615 | .Vb 7 |
|
|
1616 | \& // create io watchers for each fd and a timer before blocking |
|
|
1617 | \& static void |
|
|
1618 | \& adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
|
|
1619 | \& { |
|
|
1620 | \& int timeout = 3600000;truct pollfd fds [nfd]; |
|
|
1621 | \& // actual code will need to loop here and realloc etc. |
|
|
1622 | \& adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
|
|
1623 | .Ve |
|
|
1624 | .PP |
|
|
1625 | .Vb 3 |
|
|
1626 | \& /* the callback is illegal, but won't be called as we stop during check */ |
|
|
1627 | \& ev_timer_init (&tw, 0, timeout * 1e-3); |
|
|
1628 | \& ev_timer_start (loop, &tw); |
|
|
1629 | .Ve |
|
|
1630 | .PP |
|
|
1631 | .Vb 6 |
|
|
1632 | \& // create on ev_io per pollfd |
|
|
1633 | \& for (int i = 0; i < nfd; ++i) |
|
|
1634 | \& { |
|
|
1635 | \& ev_io_init (iow + i, io_cb, fds [i].fd, |
|
|
1636 | \& ((fds [i].events & POLLIN ? EV_READ : 0) |
|
|
1637 | \& | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
|
|
1638 | .Ve |
|
|
1639 | .PP |
|
|
1640 | .Vb 5 |
|
|
1641 | \& fds [i].revents = 0; |
|
|
1642 | \& iow [i].data = fds + i; |
|
|
1643 | \& ev_io_start (loop, iow + i); |
|
|
1644 | \& } |
|
|
1645 | \& } |
|
|
1646 | .Ve |
|
|
1647 | .PP |
|
|
1648 | .Vb 5 |
|
|
1649 | \& // stop all watchers after blocking |
|
|
1650 | \& static void |
|
|
1651 | \& adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
|
|
1652 | \& { |
|
|
1653 | \& ev_timer_stop (loop, &tw); |
|
|
1654 | .Ve |
|
|
1655 | .PP |
|
|
1656 | .Vb 2 |
|
|
1657 | \& for (int i = 0; i < nfd; ++i) |
|
|
1658 | \& ev_io_stop (loop, iow + i); |
|
|
1659 | .Ve |
|
|
1660 | .PP |
|
|
1661 | .Vb 2 |
|
|
1662 | \& adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
|
|
1663 | \& } |
|
|
1664 | .Ve |
|
|
1665 | .ie n .Sh """ev_embed"" \- when one backend isn't enough..." |
|
|
1666 | .el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..." |
|
|
1667 | .IX Subsection "ev_embed - when one backend isn't enough..." |
|
|
1668 | This is a rather advanced watcher type that lets you embed one event loop |
|
|
1669 | into another (currently only \f(CW\*(C`ev_io\*(C'\fR events are supported in the embedded |
|
|
1670 | loop, other types of watchers might be handled in a delayed or incorrect |
|
|
1671 | fashion and must not be used). |
|
|
1672 | .PP |
|
|
1673 | There are primarily two reasons you would want that: work around bugs and |
|
|
1674 | prioritise I/O. |
|
|
1675 | .PP |
|
|
1676 | As an example for a bug workaround, the kqueue backend might only support |
|
|
1677 | sockets on some platform, so it is unusable as generic backend, but you |
|
|
1678 | still want to make use of it because you have many sockets and it scales |
|
|
1679 | so nicely. In this case, you would create a kqueue-based loop and embed it |
|
|
1680 | into your default loop (which might use e.g. poll). Overall operation will |
|
|
1681 | be a bit slower because first libev has to poll and then call kevent, but |
|
|
1682 | at least you can use both at what they are best. |
|
|
1683 | .PP |
|
|
1684 | As for prioritising I/O: rarely you have the case where some fds have |
|
|
1685 | to be watched and handled very quickly (with low latency), and even |
|
|
1686 | priorities and idle watchers might have too much overhead. In this case |
|
|
1687 | you would put all the high priority stuff in one loop and all the rest in |
|
|
1688 | a second one, and embed the second one in the first. |
|
|
1689 | .PP |
|
|
1690 | As long as the watcher is active, the callback will be invoked every time |
|
|
1691 | there might be events pending in the embedded loop. The callback must then |
|
|
1692 | call \f(CW\*(C`ev_embed_sweep (mainloop, watcher)\*(C'\fR to make a single sweep and invoke |
|
|
1693 | their callbacks (you could also start an idle watcher to give the embedded |
|
|
1694 | loop strictly lower priority for example). You can also set the callback |
|
|
1695 | to \f(CW0\fR, in which case the embed watcher will automatically execute the |
|
|
1696 | embedded loop sweep. |
|
|
1697 | .PP |
|
|
1698 | As long as the watcher is started it will automatically handle events. The |
|
|
1699 | callback will be invoked whenever some events have been handled. You can |
|
|
1700 | set the callback to \f(CW0\fR to avoid having to specify one if you are not |
|
|
1701 | interested in that. |
|
|
1702 | .PP |
|
|
1703 | Also, there have not currently been made special provisions for forking: |
|
|
1704 | when you fork, you not only have to call \f(CW\*(C`ev_loop_fork\*(C'\fR on both loops, |
|
|
1705 | but you will also have to stop and restart any \f(CW\*(C`ev_embed\*(C'\fR watchers |
|
|
1706 | yourself. |
|
|
1707 | .PP |
|
|
1708 | Unfortunately, not all backends are embeddable, only the ones returned by |
|
|
1709 | \&\f(CW\*(C`ev_embeddable_backends\*(C'\fR are, which, unfortunately, does not include any |
|
|
1710 | portable one. |
|
|
1711 | .PP |
|
|
1712 | So when you want to use this feature you will always have to be prepared |
|
|
1713 | that you cannot get an embeddable loop. The recommended way to get around |
|
|
1714 | this is to have a separate variables for your embeddable loop, try to |
|
|
1715 | create it, and if that fails, use the normal loop for everything: |
|
|
1716 | .PP |
|
|
1717 | .Vb 3 |
|
|
1718 | \& struct ev_loop *loop_hi = ev_default_init (0); |
|
|
1719 | \& struct ev_loop *loop_lo = 0; |
|
|
1720 | \& struct ev_embed embed; |
|
|
1721 | .Ve |
|
|
1722 | .PP |
|
|
1723 | .Vb 5 |
|
|
1724 | \& // see if there is a chance of getting one that works |
|
|
1725 | \& // (remember that a flags value of 0 means autodetection) |
|
|
1726 | \& loop_lo = ev_embeddable_backends () & ev_recommended_backends () |
|
|
1727 | \& ? ev_loop_new (ev_embeddable_backends () & ev_recommended_backends ()) |
|
|
1728 | \& : 0; |
|
|
1729 | .Ve |
|
|
1730 | .PP |
|
|
1731 | .Vb 8 |
|
|
1732 | \& // if we got one, then embed it, otherwise default to loop_hi |
|
|
1733 | \& if (loop_lo) |
|
|
1734 | \& { |
|
|
1735 | \& ev_embed_init (&embed, 0, loop_lo); |
|
|
1736 | \& ev_embed_start (loop_hi, &embed); |
|
|
1737 | \& } |
|
|
1738 | \& else |
|
|
1739 | \& loop_lo = loop_hi; |
|
|
1740 | .Ve |
|
|
1741 | .IP "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
|
|
1742 | .IX Item "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" |
|
|
1743 | .PD 0 |
|
|
1744 | .IP "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
|
|
1745 | .IX Item "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" |
|
|
1746 | .PD |
|
|
1747 | Configures the watcher to embed the given loop, which must be |
|
|
1748 | embeddable. If the callback is \f(CW0\fR, then \f(CW\*(C`ev_embed_sweep\*(C'\fR will be |
|
|
1749 | invoked automatically, otherwise it is the responsibility of the callback |
|
|
1750 | to invoke it (it will continue to be called until the sweep has been done, |
|
|
1751 | if you do not want thta, you need to temporarily stop the embed watcher). |
|
|
1752 | .IP "ev_embed_sweep (loop, ev_embed *)" 4 |
|
|
1753 | .IX Item "ev_embed_sweep (loop, ev_embed *)" |
|
|
1754 | Make a single, non-blocking sweep over the embedded loop. This works |
|
|
1755 | similarly to \f(CW\*(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\*(C'\fR, but in the most |
|
|
1756 | apropriate way for embedded loops. |
|
|
1757 | .IP "struct ev_loop *loop [read\-only]" 4 |
|
|
1758 | .IX Item "struct ev_loop *loop [read-only]" |
|
|
1759 | The embedded event loop. |
|
|
1760 | .ie n .Sh """ev_fork"" \- the audacity to resume the event loop after a fork" |
|
|
1761 | .el .Sh "\f(CWev_fork\fP \- the audacity to resume the event loop after a fork" |
|
|
1762 | .IX Subsection "ev_fork - the audacity to resume the event loop after a fork" |
|
|
1763 | Fork watchers are called when a \f(CW\*(C`fork ()\*(C'\fR was detected (usually because |
|
|
1764 | whoever is a good citizen cared to tell libev about it by calling |
|
|
1765 | \&\f(CW\*(C`ev_default_fork\*(C'\fR or \f(CW\*(C`ev_loop_fork\*(C'\fR). The invocation is done before the |
|
|
1766 | event loop blocks next and before \f(CW\*(C`ev_check\*(C'\fR watchers are being called, |
|
|
1767 | and only in the child after the fork. If whoever good citizen calling |
|
|
1768 | \&\f(CW\*(C`ev_default_fork\*(C'\fR cheats and calls it in the wrong process, the fork |
|
|
1769 | handlers will be invoked, too, of course. |
|
|
1770 | .IP "ev_fork_init (ev_signal *, callback)" 4 |
|
|
1771 | .IX Item "ev_fork_init (ev_signal *, callback)" |
|
|
1772 | Initialises and configures the fork watcher \- it has no parameters of any |
|
|
1773 | kind. There is a \f(CW\*(C`ev_fork_set\*(C'\fR macro, but using it is utterly pointless, |
|
|
1774 | believe me. |
949 | .SH "OTHER FUNCTIONS" |
1775 | .SH "OTHER FUNCTIONS" |
950 | .IX Header "OTHER FUNCTIONS" |
1776 | .IX Header "OTHER FUNCTIONS" |
951 | There are some other functions of possible interest. Described. Here. Now. |
1777 | There are some other functions of possible interest. Described. Here. Now. |
952 | .IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4 |
1778 | .IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4 |
953 | .IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" |
1779 | .IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" |
… | |
… | |
982 | .Ve |
1808 | .Ve |
983 | .Sp |
1809 | .Sp |
984 | .Vb 1 |
1810 | .Vb 1 |
985 | \& ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0); |
1811 | \& ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0); |
986 | .Ve |
1812 | .Ve |
987 | .IP "ev_feed_event (loop, watcher, int events)" 4 |
1813 | .IP "ev_feed_event (ev_loop *, watcher *, int revents)" 4 |
988 | .IX Item "ev_feed_event (loop, watcher, int events)" |
1814 | .IX Item "ev_feed_event (ev_loop *, watcher *, int revents)" |
989 | Feeds the given event set into the event loop, as if the specified event |
1815 | Feeds the given event set into the event loop, as if the specified event |
990 | had happened for the specified watcher (which must be a pointer to an |
1816 | had happened for the specified watcher (which must be a pointer to an |
991 | initialised but not necessarily started event watcher). |
1817 | initialised but not necessarily started event watcher). |
992 | .IP "ev_feed_fd_event (loop, int fd, int revents)" 4 |
1818 | .IP "ev_feed_fd_event (ev_loop *, int fd, int revents)" 4 |
993 | .IX Item "ev_feed_fd_event (loop, int fd, int revents)" |
1819 | .IX Item "ev_feed_fd_event (ev_loop *, int fd, int revents)" |
994 | Feed an event on the given fd, as if a file descriptor backend detected |
1820 | Feed an event on the given fd, as if a file descriptor backend detected |
995 | the given events it. |
1821 | the given events it. |
996 | .IP "ev_feed_signal_event (loop, int signum)" 4 |
1822 | .IP "ev_feed_signal_event (ev_loop *loop, int signum)" 4 |
997 | .IX Item "ev_feed_signal_event (loop, int signum)" |
1823 | .IX Item "ev_feed_signal_event (ev_loop *loop, int signum)" |
998 | Feed an event as if the given signal occured (loop must be the default loop!). |
1824 | Feed an event as if the given signal occured (\f(CW\*(C`loop\*(C'\fR must be the default |
|
|
1825 | loop!). |
999 | .SH "LIBEVENT EMULATION" |
1826 | .SH "LIBEVENT EMULATION" |
1000 | .IX Header "LIBEVENT EMULATION" |
1827 | .IX Header "LIBEVENT EMULATION" |
1001 | Libev offers a compatibility emulation layer for libevent. It cannot |
1828 | Libev offers a compatibility emulation layer for libevent. It cannot |
1002 | emulate the internals of libevent, so here are some usage hints: |
1829 | emulate the internals of libevent, so here are some usage hints: |
1003 | .IP "* Use it by including <event.h>, as usual." 4 |
1830 | .IP "* Use it by including <event.h>, as usual." 4 |
… | |
… | |
1014 | .IP "* The libev emulation is \fInot\fR \s-1ABI\s0 compatible to libevent, you need to use the libev header file and library." 4 |
1841 | .IP "* The libev emulation is \fInot\fR \s-1ABI\s0 compatible to libevent, you need to use the libev header file and library." 4 |
1015 | .IX Item "The libev emulation is not ABI compatible to libevent, you need to use the libev header file and library." |
1842 | .IX Item "The libev emulation is not ABI compatible to libevent, you need to use the libev header file and library." |
1016 | .PD |
1843 | .PD |
1017 | .SH "\*(C+ SUPPORT" |
1844 | .SH "\*(C+ SUPPORT" |
1018 | .IX Header " SUPPORT" |
1845 | .IX Header " SUPPORT" |
1019 | \&\s-1TBD\s0. |
1846 | Libev comes with some simplistic wrapper classes for \*(C+ that mainly allow |
|
|
1847 | you to use some convinience methods to start/stop watchers and also change |
|
|
1848 | the callback model to a model using method callbacks on objects. |
|
|
1849 | .PP |
|
|
1850 | To use it, |
|
|
1851 | .PP |
|
|
1852 | .Vb 1 |
|
|
1853 | \& #include <ev++.h> |
|
|
1854 | .Ve |
|
|
1855 | .PP |
|
|
1856 | (it is not installed by default). This automatically includes \fIev.h\fR |
|
|
1857 | and puts all of its definitions (many of them macros) into the global |
|
|
1858 | namespace. All \*(C+ specific things are put into the \f(CW\*(C`ev\*(C'\fR namespace. |
|
|
1859 | .PP |
|
|
1860 | It should support all the same embedding options as \fIev.h\fR, most notably |
|
|
1861 | \&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. |
|
|
1862 | .PP |
|
|
1863 | Here is a list of things available in the \f(CW\*(C`ev\*(C'\fR namespace: |
|
|
1864 | .ie n .IP """ev::READ""\fR, \f(CW""ev::WRITE"" etc." 4 |
|
|
1865 | .el .IP "\f(CWev::READ\fR, \f(CWev::WRITE\fR etc." 4 |
|
|
1866 | .IX Item "ev::READ, ev::WRITE etc." |
|
|
1867 | These are just enum values with the same values as the \f(CW\*(C`EV_READ\*(C'\fR etc. |
|
|
1868 | macros from \fIev.h\fR. |
|
|
1869 | .ie n .IP """ev::tstamp""\fR, \f(CW""ev::now""" 4 |
|
|
1870 | .el .IP "\f(CWev::tstamp\fR, \f(CWev::now\fR" 4 |
|
|
1871 | .IX Item "ev::tstamp, ev::now" |
|
|
1872 | Aliases to the same types/functions as with the \f(CW\*(C`ev_\*(C'\fR prefix. |
|
|
1873 | .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 |
|
|
1874 | .el .IP "\f(CWev::io\fR, \f(CWev::timer\fR, \f(CWev::periodic\fR, \f(CWev::idle\fR, \f(CWev::sig\fR etc." 4 |
|
|
1875 | .IX Item "ev::io, ev::timer, ev::periodic, ev::idle, ev::sig etc." |
|
|
1876 | For each \f(CW\*(C`ev_TYPE\*(C'\fR watcher in \fIev.h\fR there is a corresponding class of |
|
|
1877 | the same name in the \f(CW\*(C`ev\*(C'\fR namespace, with the exception of \f(CW\*(C`ev_signal\*(C'\fR |
|
|
1878 | which is called \f(CW\*(C`ev::sig\*(C'\fR to avoid clashes with the \f(CW\*(C`signal\*(C'\fR macro |
|
|
1879 | defines by many implementations. |
|
|
1880 | .Sp |
|
|
1881 | All of those classes have these methods: |
|
|
1882 | .RS 4 |
|
|
1883 | .IP "ev::TYPE::TYPE (object *, object::method *)" 4 |
|
|
1884 | .IX Item "ev::TYPE::TYPE (object *, object::method *)" |
|
|
1885 | .PD 0 |
|
|
1886 | .IP "ev::TYPE::TYPE (object *, object::method *, struct ev_loop *)" 4 |
|
|
1887 | .IX Item "ev::TYPE::TYPE (object *, object::method *, struct ev_loop *)" |
|
|
1888 | .IP "ev::TYPE::~TYPE" 4 |
|
|
1889 | .IX Item "ev::TYPE::~TYPE" |
|
|
1890 | .PD |
|
|
1891 | The constructor takes a pointer to an object and a method pointer to |
|
|
1892 | the event handler callback to call in this class. The constructor calls |
|
|
1893 | \&\f(CW\*(C`ev_init\*(C'\fR for you, which means you have to call the \f(CW\*(C`set\*(C'\fR method |
|
|
1894 | before starting it. If you do not specify a loop then the constructor |
|
|
1895 | automatically associates the default loop with this watcher. |
|
|
1896 | .Sp |
|
|
1897 | The destructor automatically stops the watcher if it is active. |
|
|
1898 | .IP "w\->set (struct ev_loop *)" 4 |
|
|
1899 | .IX Item "w->set (struct ev_loop *)" |
|
|
1900 | Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only |
|
|
1901 | do this when the watcher is inactive (and not pending either). |
|
|
1902 | .IP "w\->set ([args])" 4 |
|
|
1903 | .IX Item "w->set ([args])" |
|
|
1904 | Basically the same as \f(CW\*(C`ev_TYPE_set\*(C'\fR, with the same args. Must be |
|
|
1905 | called at least once. Unlike the C counterpart, an active watcher gets |
|
|
1906 | automatically stopped and restarted. |
|
|
1907 | .IP "w\->start ()" 4 |
|
|
1908 | .IX Item "w->start ()" |
|
|
1909 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument as the |
|
|
1910 | constructor already takes the loop. |
|
|
1911 | .IP "w\->stop ()" 4 |
|
|
1912 | .IX Item "w->stop ()" |
|
|
1913 | Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument. |
|
|
1914 | .ie n .IP "w\->again () ""ev::timer""\fR, \f(CW""ev::periodic"" only" 4 |
|
|
1915 | .el .IP "w\->again () \f(CWev::timer\fR, \f(CWev::periodic\fR only" 4 |
|
|
1916 | .IX Item "w->again () ev::timer, ev::periodic only" |
|
|
1917 | For \f(CW\*(C`ev::timer\*(C'\fR and \f(CW\*(C`ev::periodic\*(C'\fR, this invokes the corresponding |
|
|
1918 | \&\f(CW\*(C`ev_TYPE_again\*(C'\fR function. |
|
|
1919 | .ie n .IP "w\->sweep () ""ev::embed"" only" 4 |
|
|
1920 | .el .IP "w\->sweep () \f(CWev::embed\fR only" 4 |
|
|
1921 | .IX Item "w->sweep () ev::embed only" |
|
|
1922 | Invokes \f(CW\*(C`ev_embed_sweep\*(C'\fR. |
|
|
1923 | .ie n .IP "w\->update () ""ev::stat"" only" 4 |
|
|
1924 | .el .IP "w\->update () \f(CWev::stat\fR only" 4 |
|
|
1925 | .IX Item "w->update () ev::stat only" |
|
|
1926 | Invokes \f(CW\*(C`ev_stat_stat\*(C'\fR. |
|
|
1927 | .RE |
|
|
1928 | .RS 4 |
|
|
1929 | .RE |
|
|
1930 | .PP |
|
|
1931 | Example: Define a class with an \s-1IO\s0 and idle watcher, start one of them in |
|
|
1932 | the constructor. |
|
|
1933 | .PP |
|
|
1934 | .Vb 4 |
|
|
1935 | \& class myclass |
|
|
1936 | \& { |
|
|
1937 | \& ev_io io; void io_cb (ev::io &w, int revents); |
|
|
1938 | \& ev_idle idle void idle_cb (ev::idle &w, int revents); |
|
|
1939 | .Ve |
|
|
1940 | .PP |
|
|
1941 | .Vb 2 |
|
|
1942 | \& myclass (); |
|
|
1943 | \& } |
|
|
1944 | .Ve |
|
|
1945 | .PP |
|
|
1946 | .Vb 6 |
|
|
1947 | \& myclass::myclass (int fd) |
|
|
1948 | \& : io (this, &myclass::io_cb), |
|
|
1949 | \& idle (this, &myclass::idle_cb) |
|
|
1950 | \& { |
|
|
1951 | \& io.start (fd, ev::READ); |
|
|
1952 | \& } |
|
|
1953 | .Ve |
|
|
1954 | .SH "MACRO MAGIC" |
|
|
1955 | .IX Header "MACRO MAGIC" |
|
|
1956 | Libev can be compiled with a variety of options, the most fundemantal is |
|
|
1957 | \&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines wether (most) functions and |
|
|
1958 | callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument. |
|
|
1959 | .PP |
|
|
1960 | To make it easier to write programs that cope with either variant, the |
|
|
1961 | following macros are defined: |
|
|
1962 | .ie n .IP """EV_A""\fR, \f(CW""EV_A_""" 4 |
|
|
1963 | .el .IP "\f(CWEV_A\fR, \f(CWEV_A_\fR" 4 |
|
|
1964 | .IX Item "EV_A, EV_A_" |
|
|
1965 | This provides the loop \fIargument\fR for functions, if one is required (\*(L"ev |
|
|
1966 | loop argument\*(R"). The \f(CW\*(C`EV_A\*(C'\fR form is used when this is the sole argument, |
|
|
1967 | \&\f(CW\*(C`EV_A_\*(C'\fR is used when other arguments are following. Example: |
|
|
1968 | .Sp |
|
|
1969 | .Vb 3 |
|
|
1970 | \& ev_unref (EV_A); |
|
|
1971 | \& ev_timer_add (EV_A_ watcher); |
|
|
1972 | \& ev_loop (EV_A_ 0); |
|
|
1973 | .Ve |
|
|
1974 | .Sp |
|
|
1975 | It assumes the variable \f(CW\*(C`loop\*(C'\fR of type \f(CW\*(C`struct ev_loop *\*(C'\fR is in scope, |
|
|
1976 | which is often provided by the following macro. |
|
|
1977 | .ie n .IP """EV_P""\fR, \f(CW""EV_P_""" 4 |
|
|
1978 | .el .IP "\f(CWEV_P\fR, \f(CWEV_P_\fR" 4 |
|
|
1979 | .IX Item "EV_P, EV_P_" |
|
|
1980 | This provides the loop \fIparameter\fR for functions, if one is required (\*(L"ev |
|
|
1981 | loop parameter\*(R"). The \f(CW\*(C`EV_P\*(C'\fR form is used when this is the sole parameter, |
|
|
1982 | \&\f(CW\*(C`EV_P_\*(C'\fR is used when other parameters are following. Example: |
|
|
1983 | .Sp |
|
|
1984 | .Vb 2 |
|
|
1985 | \& // this is how ev_unref is being declared |
|
|
1986 | \& static void ev_unref (EV_P); |
|
|
1987 | .Ve |
|
|
1988 | .Sp |
|
|
1989 | .Vb 2 |
|
|
1990 | \& // this is how you can declare your typical callback |
|
|
1991 | \& static void cb (EV_P_ ev_timer *w, int revents) |
|
|
1992 | .Ve |
|
|
1993 | .Sp |
|
|
1994 | It declares a parameter \f(CW\*(C`loop\*(C'\fR of type \f(CW\*(C`struct ev_loop *\*(C'\fR, quite |
|
|
1995 | suitable for use with \f(CW\*(C`EV_A\*(C'\fR. |
|
|
1996 | .ie n .IP """EV_DEFAULT""\fR, \f(CW""EV_DEFAULT_""" 4 |
|
|
1997 | .el .IP "\f(CWEV_DEFAULT\fR, \f(CWEV_DEFAULT_\fR" 4 |
|
|
1998 | .IX Item "EV_DEFAULT, EV_DEFAULT_" |
|
|
1999 | Similar to the other two macros, this gives you the value of the default |
|
|
2000 | loop, if multiple loops are supported (\*(L"ev loop default\*(R"). |
|
|
2001 | .PP |
|
|
2002 | Example: Declare and initialise a check watcher, working regardless of |
|
|
2003 | wether multiple loops are supported or not. |
|
|
2004 | .PP |
|
|
2005 | .Vb 5 |
|
|
2006 | \& static void |
|
|
2007 | \& check_cb (EV_P_ ev_timer *w, int revents) |
|
|
2008 | \& { |
|
|
2009 | \& ev_check_stop (EV_A_ w); |
|
|
2010 | \& } |
|
|
2011 | .Ve |
|
|
2012 | .PP |
|
|
2013 | .Vb 4 |
|
|
2014 | \& ev_check check; |
|
|
2015 | \& ev_check_init (&check, check_cb); |
|
|
2016 | \& ev_check_start (EV_DEFAULT_ &check); |
|
|
2017 | \& ev_loop (EV_DEFAULT_ 0); |
|
|
2018 | .Ve |
|
|
2019 | .SH "EMBEDDING" |
|
|
2020 | .IX Header "EMBEDDING" |
|
|
2021 | Libev can (and often is) directly embedded into host |
|
|
2022 | applications. Examples of applications that embed it include the Deliantra |
|
|
2023 | Game Server, the \s-1EV\s0 perl module, the \s-1GNU\s0 Virtual Private Ethernet (gvpe) |
|
|
2024 | and rxvt\-unicode. |
|
|
2025 | .PP |
|
|
2026 | The goal is to enable you to just copy the neecssary files into your |
|
|
2027 | source directory without having to change even a single line in them, so |
|
|
2028 | you can easily upgrade by simply copying (or having a checked-out copy of |
|
|
2029 | libev somewhere in your source tree). |
|
|
2030 | .Sh "\s-1FILESETS\s0" |
|
|
2031 | .IX Subsection "FILESETS" |
|
|
2032 | Depending on what features you need you need to include one or more sets of files |
|
|
2033 | in your app. |
|
|
2034 | .PP |
|
|
2035 | \fI\s-1CORE\s0 \s-1EVENT\s0 \s-1LOOP\s0\fR |
|
|
2036 | .IX Subsection "CORE EVENT LOOP" |
|
|
2037 | .PP |
|
|
2038 | To include only the libev core (all the \f(CW\*(C`ev_*\*(C'\fR functions), with manual |
|
|
2039 | configuration (no autoconf): |
|
|
2040 | .PP |
|
|
2041 | .Vb 2 |
|
|
2042 | \& #define EV_STANDALONE 1 |
|
|
2043 | \& #include "ev.c" |
|
|
2044 | .Ve |
|
|
2045 | .PP |
|
|
2046 | This will automatically include \fIev.h\fR, too, and should be done in a |
|
|
2047 | single C source file only to provide the function implementations. To use |
|
|
2048 | it, do the same for \fIev.h\fR in all files wishing to use this \s-1API\s0 (best |
|
|
2049 | done by writing a wrapper around \fIev.h\fR that you can include instead and |
|
|
2050 | where you can put other configuration options): |
|
|
2051 | .PP |
|
|
2052 | .Vb 2 |
|
|
2053 | \& #define EV_STANDALONE 1 |
|
|
2054 | \& #include "ev.h" |
|
|
2055 | .Ve |
|
|
2056 | .PP |
|
|
2057 | Both header files and implementation files can be compiled with a \*(C+ |
|
|
2058 | compiler (at least, thats a stated goal, and breakage will be treated |
|
|
2059 | as a bug). |
|
|
2060 | .PP |
|
|
2061 | You need the following files in your source tree, or in a directory |
|
|
2062 | in your include path (e.g. in libev/ when using \-Ilibev): |
|
|
2063 | .PP |
|
|
2064 | .Vb 4 |
|
|
2065 | \& ev.h |
|
|
2066 | \& ev.c |
|
|
2067 | \& ev_vars.h |
|
|
2068 | \& ev_wrap.h |
|
|
2069 | .Ve |
|
|
2070 | .PP |
|
|
2071 | .Vb 1 |
|
|
2072 | \& ev_win32.c required on win32 platforms only |
|
|
2073 | .Ve |
|
|
2074 | .PP |
|
|
2075 | .Vb 5 |
|
|
2076 | \& ev_select.c only when select backend is enabled (which is by default) |
|
|
2077 | \& ev_poll.c only when poll backend is enabled (disabled by default) |
|
|
2078 | \& ev_epoll.c only when the epoll backend is enabled (disabled by default) |
|
|
2079 | \& ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
|
|
2080 | \& ev_port.c only when the solaris port backend is enabled (disabled by default) |
|
|
2081 | .Ve |
|
|
2082 | .PP |
|
|
2083 | \&\fIev.c\fR includes the backend files directly when enabled, so you only need |
|
|
2084 | to compile this single file. |
|
|
2085 | .PP |
|
|
2086 | \fI\s-1LIBEVENT\s0 \s-1COMPATIBILITY\s0 \s-1API\s0\fR |
|
|
2087 | .IX Subsection "LIBEVENT COMPATIBILITY API" |
|
|
2088 | .PP |
|
|
2089 | To include the libevent compatibility \s-1API\s0, also include: |
|
|
2090 | .PP |
|
|
2091 | .Vb 1 |
|
|
2092 | \& #include "event.c" |
|
|
2093 | .Ve |
|
|
2094 | .PP |
|
|
2095 | in the file including \fIev.c\fR, and: |
|
|
2096 | .PP |
|
|
2097 | .Vb 1 |
|
|
2098 | \& #include "event.h" |
|
|
2099 | .Ve |
|
|
2100 | .PP |
|
|
2101 | in the files that want to use the libevent \s-1API\s0. This also includes \fIev.h\fR. |
|
|
2102 | .PP |
|
|
2103 | You need the following additional files for this: |
|
|
2104 | .PP |
|
|
2105 | .Vb 2 |
|
|
2106 | \& event.h |
|
|
2107 | \& event.c |
|
|
2108 | .Ve |
|
|
2109 | .PP |
|
|
2110 | \fI\s-1AUTOCONF\s0 \s-1SUPPORT\s0\fR |
|
|
2111 | .IX Subsection "AUTOCONF SUPPORT" |
|
|
2112 | .PP |
|
|
2113 | Instead of using \f(CW\*(C`EV_STANDALONE=1\*(C'\fR and providing your config in |
|
|
2114 | whatever way you want, you can also \f(CW\*(C`m4_include([libev.m4])\*(C'\fR in your |
|
|
2115 | \&\fIconfigure.ac\fR and leave \f(CW\*(C`EV_STANDALONE\*(C'\fR undefined. \fIev.c\fR will then |
|
|
2116 | include \fIconfig.h\fR and configure itself accordingly. |
|
|
2117 | .PP |
|
|
2118 | For this of course you need the m4 file: |
|
|
2119 | .PP |
|
|
2120 | .Vb 1 |
|
|
2121 | \& libev.m4 |
|
|
2122 | .Ve |
|
|
2123 | .Sh "\s-1PREPROCESSOR\s0 \s-1SYMBOLS/MACROS\s0" |
|
|
2124 | .IX Subsection "PREPROCESSOR SYMBOLS/MACROS" |
|
|
2125 | Libev can be configured via a variety of preprocessor symbols you have to define |
|
|
2126 | before including any of its files. The default is not to build for multiplicity |
|
|
2127 | and only include the select backend. |
|
|
2128 | .IP "\s-1EV_STANDALONE\s0" 4 |
|
|
2129 | .IX Item "EV_STANDALONE" |
|
|
2130 | Must always be \f(CW1\fR if you do not use autoconf configuration, which |
|
|
2131 | keeps libev from including \fIconfig.h\fR, and it also defines dummy |
|
|
2132 | implementations for some libevent functions (such as logging, which is not |
|
|
2133 | supported). It will also not define any of the structs usually found in |
|
|
2134 | \&\fIevent.h\fR that are not directly supported by the libev core alone. |
|
|
2135 | .IP "\s-1EV_USE_MONOTONIC\s0" 4 |
|
|
2136 | .IX Item "EV_USE_MONOTONIC" |
|
|
2137 | If defined to be \f(CW1\fR, libev will try to detect the availability of the |
|
|
2138 | monotonic clock option at both compiletime and runtime. Otherwise no use |
|
|
2139 | of the monotonic clock option will be attempted. If you enable this, you |
|
|
2140 | usually have to link against librt or something similar. Enabling it when |
|
|
2141 | the functionality isn't available is safe, though, althoguh you have |
|
|
2142 | to make sure you link against any libraries where the \f(CW\*(C`clock_gettime\*(C'\fR |
|
|
2143 | function is hiding in (often \fI\-lrt\fR). |
|
|
2144 | .IP "\s-1EV_USE_REALTIME\s0" 4 |
|
|
2145 | .IX Item "EV_USE_REALTIME" |
|
|
2146 | If defined to be \f(CW1\fR, libev will try to detect the availability of the |
|
|
2147 | realtime clock option at compiletime (and assume its availability at |
|
|
2148 | runtime if successful). Otherwise no use of the realtime clock option will |
|
|
2149 | be attempted. This effectively replaces \f(CW\*(C`gettimeofday\*(C'\fR by \f(CW\*(C`clock_get |
|
|
2150 | (CLOCK_REALTIME, ...)\*(C'\fR and will not normally affect correctness. See tzhe note about libraries |
|
|
2151 | in the description of \f(CW\*(C`EV_USE_MONOTONIC\*(C'\fR, though. |
|
|
2152 | .IP "\s-1EV_USE_SELECT\s0" 4 |
|
|
2153 | .IX Item "EV_USE_SELECT" |
|
|
2154 | If undefined or defined to be \f(CW1\fR, libev will compile in support for the |
|
|
2155 | \&\f(CW\*(C`select\*(C'\fR(2) backend. No attempt at autodetection will be done: if no |
|
|
2156 | other method takes over, select will be it. Otherwise the select backend |
|
|
2157 | will not be compiled in. |
|
|
2158 | .IP "\s-1EV_SELECT_USE_FD_SET\s0" 4 |
|
|
2159 | .IX Item "EV_SELECT_USE_FD_SET" |
|
|
2160 | If defined to \f(CW1\fR, then the select backend will use the system \f(CW\*(C`fd_set\*(C'\fR |
|
|
2161 | structure. This is useful if libev doesn't compile due to a missing |
|
|
2162 | \&\f(CW\*(C`NFDBITS\*(C'\fR or \f(CW\*(C`fd_mask\*(C'\fR definition or it misguesses the bitset layout on |
|
|
2163 | exotic systems. This usually limits the range of file descriptors to some |
|
|
2164 | low limit such as 1024 or might have other limitations (winsocket only |
|
|
2165 | allows 64 sockets). The \f(CW\*(C`FD_SETSIZE\*(C'\fR macro, set before compilation, might |
|
|
2166 | influence the size of the \f(CW\*(C`fd_set\*(C'\fR used. |
|
|
2167 | .IP "\s-1EV_SELECT_IS_WINSOCKET\s0" 4 |
|
|
2168 | .IX Item "EV_SELECT_IS_WINSOCKET" |
|
|
2169 | When defined to \f(CW1\fR, the select backend will assume that |
|
|
2170 | select/socket/connect etc. don't understand file descriptors but |
|
|
2171 | wants osf handles on win32 (this is the case when the select to |
|
|
2172 | be used is the winsock select). This means that it will call |
|
|
2173 | \&\f(CW\*(C`_get_osfhandle\*(C'\fR on the fd to convert it to an \s-1OS\s0 handle. Otherwise, |
|
|
2174 | it is assumed that all these functions actually work on fds, even |
|
|
2175 | on win32. Should not be defined on non\-win32 platforms. |
|
|
2176 | .IP "\s-1EV_USE_POLL\s0" 4 |
|
|
2177 | .IX Item "EV_USE_POLL" |
|
|
2178 | If defined to be \f(CW1\fR, libev will compile in support for the \f(CW\*(C`poll\*(C'\fR(2) |
|
|
2179 | backend. Otherwise it will be enabled on non\-win32 platforms. It |
|
|
2180 | takes precedence over select. |
|
|
2181 | .IP "\s-1EV_USE_EPOLL\s0" 4 |
|
|
2182 | .IX Item "EV_USE_EPOLL" |
|
|
2183 | If defined to be \f(CW1\fR, libev will compile in support for the Linux |
|
|
2184 | \&\f(CW\*(C`epoll\*(C'\fR(7) backend. Its availability will be detected at runtime, |
|
|
2185 | otherwise another method will be used as fallback. This is the |
|
|
2186 | preferred backend for GNU/Linux systems. |
|
|
2187 | .IP "\s-1EV_USE_KQUEUE\s0" 4 |
|
|
2188 | .IX Item "EV_USE_KQUEUE" |
|
|
2189 | If defined to be \f(CW1\fR, libev will compile in support for the \s-1BSD\s0 style |
|
|
2190 | \&\f(CW\*(C`kqueue\*(C'\fR(2) backend. Its actual availability will be detected at runtime, |
|
|
2191 | otherwise another method will be used as fallback. This is the preferred |
|
|
2192 | backend for \s-1BSD\s0 and BSD-like systems, although on most BSDs kqueue only |
|
|
2193 | supports some types of fds correctly (the only platform we found that |
|
|
2194 | supports ptys for example was NetBSD), so kqueue might be compiled in, but |
|
|
2195 | not be used unless explicitly requested. The best way to use it is to find |
|
|
2196 | out whether kqueue supports your type of fd properly and use an embedded |
|
|
2197 | kqueue loop. |
|
|
2198 | .IP "\s-1EV_USE_PORT\s0" 4 |
|
|
2199 | .IX Item "EV_USE_PORT" |
|
|
2200 | If defined to be \f(CW1\fR, libev will compile in support for the Solaris |
|
|
2201 | 10 port style backend. Its availability will be detected at runtime, |
|
|
2202 | otherwise another method will be used as fallback. This is the preferred |
|
|
2203 | backend for Solaris 10 systems. |
|
|
2204 | .IP "\s-1EV_USE_DEVPOLL\s0" 4 |
|
|
2205 | .IX Item "EV_USE_DEVPOLL" |
|
|
2206 | reserved for future expansion, works like the \s-1USE\s0 symbols above. |
|
|
2207 | .IP "\s-1EV_USE_INOTIFY\s0" 4 |
|
|
2208 | .IX Item "EV_USE_INOTIFY" |
|
|
2209 | If defined to be \f(CW1\fR, libev will compile in support for the Linux inotify |
|
|
2210 | interface to speed up \f(CW\*(C`ev_stat\*(C'\fR watchers. Its actual availability will |
|
|
2211 | be detected at runtime. |
|
|
2212 | .IP "\s-1EV_H\s0" 4 |
|
|
2213 | .IX Item "EV_H" |
|
|
2214 | The name of the \fIev.h\fR header file used to include it. The default if |
|
|
2215 | undefined is \f(CW\*(C`<ev.h>\*(C'\fR in \fIevent.h\fR and \f(CW"ev.h"\fR in \fIev.c\fR. This |
|
|
2216 | can be used to virtually rename the \fIev.h\fR header file in case of conflicts. |
|
|
2217 | .IP "\s-1EV_CONFIG_H\s0" 4 |
|
|
2218 | .IX Item "EV_CONFIG_H" |
|
|
2219 | If \f(CW\*(C`EV_STANDALONE\*(C'\fR isn't \f(CW1\fR, this variable can be used to override |
|
|
2220 | \&\fIev.c\fR's idea of where to find the \fIconfig.h\fR file, similarly to |
|
|
2221 | \&\f(CW\*(C`EV_H\*(C'\fR, above. |
|
|
2222 | .IP "\s-1EV_EVENT_H\s0" 4 |
|
|
2223 | .IX Item "EV_EVENT_H" |
|
|
2224 | Similarly to \f(CW\*(C`EV_H\*(C'\fR, this macro can be used to override \fIevent.c\fR's idea |
|
|
2225 | of how the \fIevent.h\fR header can be found. |
|
|
2226 | .IP "\s-1EV_PROTOTYPES\s0" 4 |
|
|
2227 | .IX Item "EV_PROTOTYPES" |
|
|
2228 | If defined to be \f(CW0\fR, then \fIev.h\fR will not define any function |
|
|
2229 | prototypes, but still define all the structs and other symbols. This is |
|
|
2230 | occasionally useful if you want to provide your own wrapper functions |
|
|
2231 | around libev functions. |
|
|
2232 | .IP "\s-1EV_MULTIPLICITY\s0" 4 |
|
|
2233 | .IX Item "EV_MULTIPLICITY" |
|
|
2234 | If undefined or defined to \f(CW1\fR, then all event-loop-specific functions |
|
|
2235 | will have the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument, and you can create |
|
|
2236 | additional independent event loops. Otherwise there will be no support |
|
|
2237 | for multiple event loops and there is no first event loop pointer |
|
|
2238 | argument. Instead, all functions act on the single default loop. |
|
|
2239 | .IP "\s-1EV_PERIODIC_ENABLE\s0" 4 |
|
|
2240 | .IX Item "EV_PERIODIC_ENABLE" |
|
|
2241 | If undefined or defined to be \f(CW1\fR, then periodic timers are supported. If |
|
|
2242 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
|
|
2243 | code. |
|
|
2244 | .IP "\s-1EV_EMBED_ENABLE\s0" 4 |
|
|
2245 | .IX Item "EV_EMBED_ENABLE" |
|
|
2246 | If undefined or defined to be \f(CW1\fR, then embed watchers are supported. If |
|
|
2247 | defined to be \f(CW0\fR, then they are not. |
|
|
2248 | .IP "\s-1EV_STAT_ENABLE\s0" 4 |
|
|
2249 | .IX Item "EV_STAT_ENABLE" |
|
|
2250 | If undefined or defined to be \f(CW1\fR, then stat watchers are supported. If |
|
|
2251 | defined to be \f(CW0\fR, then they are not. |
|
|
2252 | .IP "\s-1EV_FORK_ENABLE\s0" 4 |
|
|
2253 | .IX Item "EV_FORK_ENABLE" |
|
|
2254 | If undefined or defined to be \f(CW1\fR, then fork watchers are supported. If |
|
|
2255 | defined to be \f(CW0\fR, then they are not. |
|
|
2256 | .IP "\s-1EV_MINIMAL\s0" 4 |
|
|
2257 | .IX Item "EV_MINIMAL" |
|
|
2258 | If you need to shave off some kilobytes of code at the expense of some |
|
|
2259 | speed, define this symbol to \f(CW1\fR. Currently only used for gcc to override |
|
|
2260 | some inlining decisions, saves roughly 30% codesize of amd64. |
|
|
2261 | .IP "\s-1EV_PID_HASHSIZE\s0" 4 |
|
|
2262 | .IX Item "EV_PID_HASHSIZE" |
|
|
2263 | \&\f(CW\*(C`ev_child\*(C'\fR watchers use a small hash table to distribute workload by |
|
|
2264 | pid. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), usually more |
|
|
2265 | than enough. If you need to manage thousands of children you might want to |
|
|
2266 | increase this value (\fImust\fR be a power of two). |
|
|
2267 | .IP "\s-1EV_INOTIFY_HASHSIZE\s0" 4 |
|
|
2268 | .IX Item "EV_INOTIFY_HASHSIZE" |
|
|
2269 | \&\f(CW\*(C`ev_staz\*(C'\fR watchers use a small hash table to distribute workload by |
|
|
2270 | inotify watch id. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), |
|
|
2271 | usually more than enough. If you need to manage thousands of \f(CW\*(C`ev_stat\*(C'\fR |
|
|
2272 | watchers you might want to increase this value (\fImust\fR be a power of |
|
|
2273 | two). |
|
|
2274 | .IP "\s-1EV_COMMON\s0" 4 |
|
|
2275 | .IX Item "EV_COMMON" |
|
|
2276 | By default, all watchers have a \f(CW\*(C`void *data\*(C'\fR member. By redefining |
|
|
2277 | this macro to a something else you can include more and other types of |
|
|
2278 | members. You have to define it each time you include one of the files, |
|
|
2279 | though, and it must be identical each time. |
|
|
2280 | .Sp |
|
|
2281 | For example, the perl \s-1EV\s0 module uses something like this: |
|
|
2282 | .Sp |
|
|
2283 | .Vb 3 |
|
|
2284 | \& #define EV_COMMON \e |
|
|
2285 | \& SV *self; /* contains this struct */ \e |
|
|
2286 | \& SV *cb_sv, *fh /* note no trailing ";" */ |
|
|
2287 | .Ve |
|
|
2288 | .IP "\s-1EV_CB_DECLARE\s0 (type)" 4 |
|
|
2289 | .IX Item "EV_CB_DECLARE (type)" |
|
|
2290 | .PD 0 |
|
|
2291 | .IP "\s-1EV_CB_INVOKE\s0 (watcher, revents)" 4 |
|
|
2292 | .IX Item "EV_CB_INVOKE (watcher, revents)" |
|
|
2293 | .IP "ev_set_cb (ev, cb)" 4 |
|
|
2294 | .IX Item "ev_set_cb (ev, cb)" |
|
|
2295 | .PD |
|
|
2296 | Can be used to change the callback member declaration in each watcher, |
|
|
2297 | and the way callbacks are invoked and set. Must expand to a struct member |
|
|
2298 | definition and a statement, respectively. See the \fIev.v\fR header file for |
|
|
2299 | their default definitions. One possible use for overriding these is to |
|
|
2300 | avoid the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument in all cases, or to use |
|
|
2301 | method calls instead of plain function calls in \*(C+. |
|
|
2302 | .Sh "\s-1EXAMPLES\s0" |
|
|
2303 | .IX Subsection "EXAMPLES" |
|
|
2304 | For a real-world example of a program the includes libev |
|
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2305 | verbatim, you can have a look at the \s-1EV\s0 perl module |
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2306 | (<http://software.schmorp.de/pkg/EV.html>). It has the libev files in |
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2307 | the \fIlibev/\fR subdirectory and includes them in the \fI\s-1EV/EVAPI\s0.h\fR (public |
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2308 | interface) and \fI\s-1EV\s0.xs\fR (implementation) files. Only the \fI\s-1EV\s0.xs\fR file |
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2309 | will be compiled. It is pretty complex because it provides its own header |
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2310 | file. |
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2311 | .Sp |
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2312 | The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file |
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2313 | that everybody includes and which overrides some autoconf choices: |
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2314 | .Sp |
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2315 | .Vb 4 |
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2316 | \& #define EV_USE_POLL 0 |
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2317 | \& #define EV_MULTIPLICITY 0 |
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2318 | \& #define EV_PERIODICS 0 |
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2319 | \& #define EV_CONFIG_H <config.h> |
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2320 | .Ve |
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2321 | .Sp |
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2322 | .Vb 1 |
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2323 | \& #include "ev++.h" |
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2324 | .Ve |
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2325 | .Sp |
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2326 | And a \fIev_cpp.C\fR implementation file that contains libev proper and is compiled: |
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2327 | .Sp |
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2328 | .Vb 2 |
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2329 | \& #include "ev_cpp.h" |
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2330 | \& #include "ev.c" |
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2331 | .Ve |
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2332 | .SH "COMPLEXITIES" |
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2333 | .IX Header "COMPLEXITIES" |
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2334 | In this section the complexities of (many of) the algorithms used inside |
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2335 | libev will be explained. For complexity discussions about backends see the |
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2336 | documentation for \f(CW\*(C`ev_default_init\*(C'\fR. |
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2337 | .RS 4 |
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2338 | .IP "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" 4 |
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2339 | .IX Item "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" |
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2340 | .PD 0 |
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2341 | .IP "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" 4 |
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2342 | .IX Item "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" |
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2343 | .IP "Starting io/check/prepare/idle/signal/child watchers: O(1)" 4 |
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2344 | .IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)" |
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2345 | .IP "Stopping check/prepare/idle watchers: O(1)" 4 |
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2346 | .IX Item "Stopping check/prepare/idle watchers: O(1)" |
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2347 | .IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % \s-1EV_PID_HASHSIZE\s0))" 4 |
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2348 | .IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))" |
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2349 | .IP "Finding the next timer per loop iteration: O(1)" 4 |
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2350 | .IX Item "Finding the next timer per loop iteration: O(1)" |
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2351 | .IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4 |
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2352 | .IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" |
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2353 | .IP "Activating one watcher: O(1)" 4 |
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2354 | .IX Item "Activating one watcher: O(1)" |
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2355 | .RE |
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2356 | .RS 4 |
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2357 | .PD |
1020 | .SH "AUTHOR" |
2358 | .SH "AUTHOR" |
1021 | .IX Header "AUTHOR" |
2359 | .IX Header "AUTHOR" |
1022 | Marc Lehmann <libev@schmorp.de>. |
2360 | Marc Lehmann <libev@schmorp.de>. |