… | |
… | |
126 | . ds Ae AE |
126 | . ds Ae AE |
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 "EV 1" |
132 | .TH "<STANDARD INPUT>" 1 "2007-11-24" "perl v5.8.8" "User Contributed Perl Documentation" |
132 | .TH EV 1 "2007-12-25" "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 "\s-1EXAMPLE\s0 \s-1PROGRAM\s0" |
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141 | .IX Subsection "EXAMPLE PROGRAM" |
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142 | .Vb 1 |
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143 | \& #include <ev.h> |
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144 | .Ve |
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145 | .PP |
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146 | .Vb 2 |
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147 | \& ev_io stdin_watcher; |
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148 | \& ev_timer timeout_watcher; |
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149 | .Ve |
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150 | .PP |
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151 | .Vb 8 |
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152 | \& /* called when data readable on stdin */ |
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153 | \& static void |
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154 | \& stdin_cb (EV_P_ struct ev_io *w, int revents) |
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155 | \& { |
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156 | \& /* puts ("stdin ready"); */ |
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157 | \& ev_io_stop (EV_A_ w); /* just a syntax example */ |
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158 | \& ev_unloop (EV_A_ EVUNLOOP_ALL); /* leave all loop calls */ |
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159 | \& } |
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160 | .Ve |
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161 | .PP |
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162 | .Vb 6 |
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163 | \& static void |
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164 | \& timeout_cb (EV_P_ struct ev_timer *w, int revents) |
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165 | \& { |
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166 | \& /* puts ("timeout"); */ |
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167 | \& ev_unloop (EV_A_ EVUNLOOP_ONE); /* leave one loop call */ |
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168 | \& } |
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169 | .Ve |
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170 | .PP |
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171 | .Vb 4 |
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172 | \& int |
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173 | \& main (void) |
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174 | \& { |
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175 | \& struct ev_loop *loop = ev_default_loop (0); |
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176 | .Ve |
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177 | .PP |
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178 | .Vb 3 |
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179 | \& /* initialise an io watcher, then start it */ |
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180 | \& ev_io_init (&stdin_watcher, stdin_cb, /*STDIN_FILENO*/ 0, EV_READ); |
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181 | \& ev_io_start (loop, &stdin_watcher); |
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182 | .Ve |
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183 | .PP |
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184 | .Vb 3 |
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185 | \& /* simple non-repeating 5.5 second timeout */ |
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186 | \& ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.); |
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187 | \& ev_timer_start (loop, &timeout_watcher); |
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188 | .Ve |
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189 | .PP |
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190 | .Vb 2 |
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191 | \& /* loop till timeout or data ready */ |
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192 | \& ev_loop (loop, 0); |
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193 | .Ve |
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194 | .PP |
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195 | .Vb 2 |
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196 | \& return 0; |
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197 | \& } |
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198 | .Ve |
140 | .SH "DESCRIPTION" |
199 | .SH "DESCRIPTION" |
141 | .IX Header "DESCRIPTION" |
200 | .IX Header "DESCRIPTION" |
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201 | The newest version of this document is also available as a html-formatted |
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202 | web page you might find easier to navigate when reading it for the first |
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203 | time: <http://cvs.schmorp.de/libev/ev.html>. |
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204 | .PP |
142 | Libev is an event loop: you register interest in certain events (such as a |
205 | Libev is an event loop: you register interest in certain events (such as a |
143 | file descriptor being readable or a timeout occuring), and it will manage |
206 | file descriptor being readable or a timeout occurring), and it will manage |
144 | these event sources and provide your program with events. |
207 | these event sources and provide your program with events. |
145 | .PP |
208 | .PP |
146 | To do this, it must take more or less complete control over your process |
209 | To do this, it must take more or less complete control over your process |
147 | (or thread) by executing the \fIevent loop\fR handler, and will then |
210 | (or thread) by executing the \fIevent loop\fR handler, and will then |
148 | communicate events via a callback mechanism. |
211 | communicate events via a callback mechanism. |
149 | .PP |
212 | .PP |
150 | You register interest in certain events by registering so-called \fIevent |
213 | You register interest in certain events by registering so-called \fIevent |
151 | watchers\fR, which are relatively small C structures you initialise with the |
214 | watchers\fR, which are relatively small C structures you initialise with the |
152 | details of the event, and then hand it over to libev by \fIstarting\fR the |
215 | details of the event, and then hand it over to libev by \fIstarting\fR the |
153 | watcher. |
216 | watcher. |
154 | .SH "FEATURES" |
217 | .Sh "\s-1FEATURES\s0" |
155 | .IX Header "FEATURES" |
218 | .IX Subsection "FEATURES" |
156 | Libev supports select, poll, the linux-specific epoll and the bsd-specific |
219 | Libev supports \f(CW\*(C`select\*(C'\fR, \f(CW\*(C`poll\*(C'\fR, the Linux-specific \f(CW\*(C`epoll\*(C'\fR, the |
157 | kqueue mechanisms for file descriptor events, relative timers, absolute |
220 | BSD-specific \f(CW\*(C`kqueue\*(C'\fR and the Solaris-specific event port mechanisms |
158 | timers with customised rescheduling, signal events, process status change |
221 | for file descriptor events (\f(CW\*(C`ev_io\*(C'\fR), the Linux \f(CW\*(C`inotify\*(C'\fR interface |
159 | events (related to \s-1SIGCHLD\s0), and event watchers dealing with the event |
222 | (for \f(CW\*(C`ev_stat\*(C'\fR), relative timers (\f(CW\*(C`ev_timer\*(C'\fR), absolute timers |
160 | loop mechanism itself (idle, prepare and check watchers). It also is quite |
223 | with customised rescheduling (\f(CW\*(C`ev_periodic\*(C'\fR), synchronous signals |
161 | fast (see this benchmark comparing |
224 | (\f(CW\*(C`ev_signal\*(C'\fR), process status change events (\f(CW\*(C`ev_child\*(C'\fR), and event |
162 | it to libevent for example). |
225 | watchers dealing with the event loop mechanism itself (\f(CW\*(C`ev_idle\*(C'\fR, |
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226 | \&\f(CW\*(C`ev_embed\*(C'\fR, \f(CW\*(C`ev_prepare\*(C'\fR and \f(CW\*(C`ev_check\*(C'\fR watchers) as well as |
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227 | file watchers (\f(CW\*(C`ev_stat\*(C'\fR) and even limited support for fork events |
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228 | (\f(CW\*(C`ev_fork\*(C'\fR). |
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229 | .PP |
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230 | It also is quite fast (see this |
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231 | benchmark comparing it to libevent |
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232 | for example). |
163 | .SH "CONVENTIONS" |
233 | .Sh "\s-1CONVENTIONS\s0" |
164 | .IX Header "CONVENTIONS" |
234 | .IX Subsection "CONVENTIONS" |
165 | Libev is very configurable. In this manual the default configuration |
235 | Libev is very configurable. In this manual the default configuration will |
166 | will be described, which supports multiple event loops. For more info |
236 | be described, which supports multiple event loops. For more info about |
167 | about various configuration options please have a look at the file |
237 | various configuration options please have a look at \fB\s-1EMBED\s0\fR section in |
168 | \&\fI\s-1README\s0.embed\fR in the libev distribution. If libev was configured without |
238 | this manual. If libev was configured without support for multiple event |
169 | support for multiple event loops, then all functions taking an initial |
239 | loops, then all functions taking an initial argument of name \f(CW\*(C`loop\*(C'\fR |
170 | argument of name \f(CW\*(C`loop\*(C'\fR (which is always of type \f(CW\*(C`struct ev_loop *\*(C'\fR) |
240 | (which is always of type \f(CW\*(C`struct ev_loop *\*(C'\fR) will not have this argument. |
171 | will not have this argument. |
241 | .Sh "\s-1TIME\s0 \s-1REPRESENTATION\s0" |
172 | .SH "TIME REPRESENTATION" |
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173 | .IX Header "TIME REPRESENTATION" |
242 | .IX Subsection "TIME REPRESENTATION" |
174 | Libev represents time as a single floating point number, representing the |
243 | Libev represents time as a single floating point number, representing the |
175 | (fractional) number of seconds since the (\s-1POSIX\s0) epoch (somewhere near |
244 | (fractional) number of seconds since the (\s-1POSIX\s0) epoch (somewhere near |
176 | the beginning of 1970, details are complicated, don't ask). This type is |
245 | the beginning of 1970, details are complicated, don't ask). This type is |
177 | called \f(CW\*(C`ev_tstamp\*(C'\fR, which is what you should use too. It usually aliases |
246 | called \f(CW\*(C`ev_tstamp\*(C'\fR, which is what you should use too. It usually aliases |
178 | to the \f(CW\*(C`double\*(C'\fR type in C, and when you need to do any calculations on |
247 | to the \f(CW\*(C`double\*(C'\fR type in C, and when you need to do any calculations on |
179 | it, you should treat it as such. |
248 | it, you should treat it as some floatingpoint value. Unlike the name |
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249 | component \f(CW\*(C`stamp\*(C'\fR might indicate, it is also used for time differences |
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250 | throughout libev. |
180 | .SH "GLOBAL FUNCTIONS" |
251 | .SH "GLOBAL FUNCTIONS" |
181 | .IX Header "GLOBAL FUNCTIONS" |
252 | .IX Header "GLOBAL FUNCTIONS" |
182 | These functions can be called anytime, even before initialising the |
253 | These functions can be called anytime, even before initialising the |
183 | library in any way. |
254 | library in any way. |
184 | .IP "ev_tstamp ev_time ()" 4 |
255 | .IP "ev_tstamp ev_time ()" 4 |
185 | .IX Item "ev_tstamp ev_time ()" |
256 | .IX Item "ev_tstamp ev_time ()" |
186 | Returns the current time as libev would use it. Please note that the |
257 | Returns the current time as libev would use it. Please note that the |
187 | \&\f(CW\*(C`ev_now\*(C'\fR function is usually faster and also often returns the timestamp |
258 | \&\f(CW\*(C`ev_now\*(C'\fR function is usually faster and also often returns the timestamp |
188 | you actually want to know. |
259 | you actually want to know. |
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260 | .IP "ev_sleep (ev_tstamp interval)" 4 |
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261 | .IX Item "ev_sleep (ev_tstamp interval)" |
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262 | Sleep for the given interval: The current thread will be blocked until |
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263 | either it is interrupted or the given time interval has passed. Basically |
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264 | this is a subsecond-resolution \f(CW\*(C`sleep ()\*(C'\fR. |
189 | .IP "int ev_version_major ()" 4 |
265 | .IP "int ev_version_major ()" 4 |
190 | .IX Item "int ev_version_major ()" |
266 | .IX Item "int ev_version_major ()" |
191 | .PD 0 |
267 | .PD 0 |
192 | .IP "int ev_version_minor ()" 4 |
268 | .IP "int ev_version_minor ()" 4 |
193 | .IX Item "int ev_version_minor ()" |
269 | .IX Item "int ev_version_minor ()" |
194 | .PD |
270 | .PD |
195 | You can find out the major and minor version numbers of the library |
271 | You can find out the major and minor \s-1ABI\s0 version numbers of the library |
196 | you linked against by calling the functions \f(CW\*(C`ev_version_major\*(C'\fR and |
272 | you linked against by calling the functions \f(CW\*(C`ev_version_major\*(C'\fR and |
197 | \&\f(CW\*(C`ev_version_minor\*(C'\fR. If you want, you can compare against the global |
273 | \&\f(CW\*(C`ev_version_minor\*(C'\fR. If you want, you can compare against the global |
198 | symbols \f(CW\*(C`EV_VERSION_MAJOR\*(C'\fR and \f(CW\*(C`EV_VERSION_MINOR\*(C'\fR, which specify the |
274 | symbols \f(CW\*(C`EV_VERSION_MAJOR\*(C'\fR and \f(CW\*(C`EV_VERSION_MINOR\*(C'\fR, which specify the |
199 | version of the library your program was compiled against. |
275 | version of the library your program was compiled against. |
200 | .Sp |
276 | .Sp |
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277 | These version numbers refer to the \s-1ABI\s0 version of the library, not the |
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278 | release version. |
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279 | .Sp |
201 | Usually, it's a good idea to terminate if the major versions mismatch, |
280 | Usually, it's a good idea to terminate if the major versions mismatch, |
202 | as this indicates an incompatible change. Minor versions are usually |
281 | as this indicates an incompatible change. Minor versions are usually |
203 | compatible to older versions, so a larger minor version alone is usually |
282 | compatible to older versions, so a larger minor version alone is usually |
204 | not a problem. |
283 | not a problem. |
205 | .Sp |
284 | .Sp |
206 | Example: make sure we haven't accidentally been linked against the wrong |
285 | Example: Make sure we haven't accidentally been linked against the wrong |
207 | version: |
286 | version. |
208 | .Sp |
287 | .Sp |
209 | .Vb 3 |
288 | .Vb 3 |
210 | \& assert (("libev version mismatch", |
289 | \& assert (("libev version mismatch", |
211 | \& ev_version_major () == EV_VERSION_MAJOR |
290 | \& ev_version_major () == EV_VERSION_MAJOR |
212 | \& && ev_version_minor () >= EV_VERSION_MINOR)); |
291 | \& && ev_version_minor () >= EV_VERSION_MINOR)); |
… | |
… | |
242 | recommended ones. |
321 | recommended ones. |
243 | .Sp |
322 | .Sp |
244 | See the description of \f(CW\*(C`ev_embed\*(C'\fR watchers for more info. |
323 | See the description of \f(CW\*(C`ev_embed\*(C'\fR watchers for more info. |
245 | .IP "ev_set_allocator (void *(*cb)(void *ptr, long size))" 4 |
324 | .IP "ev_set_allocator (void *(*cb)(void *ptr, long size))" 4 |
246 | .IX Item "ev_set_allocator (void *(*cb)(void *ptr, long size))" |
325 | .IX Item "ev_set_allocator (void *(*cb)(void *ptr, long size))" |
247 | Sets the allocation function to use (the prototype is similar to the |
326 | Sets the allocation function to use (the prototype is similar \- the |
248 | realloc C function, the semantics are identical). It is used to allocate |
327 | semantics is identical \- to the realloc C function). It is used to |
249 | and free memory (no surprises here). If it returns zero when memory |
328 | allocate and free memory (no surprises here). If it returns zero when |
250 | needs to be allocated, the library might abort or take some potentially |
329 | memory needs to be allocated, the library might abort or take some |
251 | destructive action. The default is your system realloc function. |
330 | potentially destructive action. The default is your system realloc |
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331 | function. |
252 | .Sp |
332 | .Sp |
253 | You could override this function in high-availability programs to, say, |
333 | You could override this function in high-availability programs to, say, |
254 | free some memory if it cannot allocate memory, to use a special allocator, |
334 | free some memory if it cannot allocate memory, to use a special allocator, |
255 | or even to sleep a while and retry until some memory is available. |
335 | or even to sleep a while and retry until some memory is available. |
256 | .Sp |
336 | .Sp |
257 | Example: replace the libev allocator with one that waits a bit and then |
337 | Example: Replace the libev allocator with one that waits a bit and then |
258 | retries: better than mine). |
338 | retries). |
259 | .Sp |
339 | .Sp |
260 | .Vb 6 |
340 | .Vb 6 |
261 | \& static void * |
341 | \& static void * |
262 | \& persistent_realloc (void *ptr, long size) |
342 | \& persistent_realloc (void *ptr, size_t size) |
263 | \& { |
343 | \& { |
264 | \& for (;;) |
344 | \& for (;;) |
265 | \& { |
345 | \& { |
266 | \& void *newptr = realloc (ptr, size); |
346 | \& void *newptr = realloc (ptr, size); |
267 | .Ve |
347 | .Ve |
… | |
… | |
289 | callback is set, then libev will expect it to remedy the sitution, no |
369 | callback is set, then libev will expect it to remedy the sitution, no |
290 | matter what, when it returns. That is, libev will generally retry the |
370 | matter what, when it returns. That is, libev will generally retry the |
291 | requested operation, or, if the condition doesn't go away, do bad stuff |
371 | requested operation, or, if the condition doesn't go away, do bad stuff |
292 | (such as abort). |
372 | (such as abort). |
293 | .Sp |
373 | .Sp |
294 | Example: do the same thing as libev does internally: |
374 | Example: This is basically the same thing that libev does internally, too. |
295 | .Sp |
375 | .Sp |
296 | .Vb 6 |
376 | .Vb 6 |
297 | \& static void |
377 | \& static void |
298 | \& fatal_error (const char *msg) |
378 | \& fatal_error (const char *msg) |
299 | \& { |
379 | \& { |
… | |
… | |
345 | or setgid) then libev will \fInot\fR look at the environment variable |
425 | or setgid) then libev will \fInot\fR look at the environment variable |
346 | \&\f(CW\*(C`LIBEV_FLAGS\*(C'\fR. Otherwise (the default), this environment variable will |
426 | \&\f(CW\*(C`LIBEV_FLAGS\*(C'\fR. Otherwise (the default), this environment variable will |
347 | override the flags completely if it is found in the environment. This is |
427 | override the flags completely if it is found in the environment. This is |
348 | useful to try out specific backends to test their performance, or to work |
428 | useful to try out specific backends to test their performance, or to work |
349 | around bugs. |
429 | around bugs. |
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430 | .ie n .IP """EVFLAG_FORKCHECK""" 4 |
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431 | .el .IP "\f(CWEVFLAG_FORKCHECK\fR" 4 |
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432 | .IX Item "EVFLAG_FORKCHECK" |
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433 | 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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434 | a fork, you can also make libev check for a fork in each iteration by |
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435 | enabling this flag. |
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436 | .Sp |
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437 | This works by calling \f(CW\*(C`getpid ()\*(C'\fR on every iteration of the loop, |
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438 | and thus this might slow down your event loop if you do a lot of loop |
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439 | iterations and little real work, but is usually not noticeable (on my |
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440 | Linux system for example, \f(CW\*(C`getpid\*(C'\fR is actually a simple 5\-insn sequence |
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441 | without a syscall and thus \fIvery\fR fast, but my Linux system also has |
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442 | \&\f(CW\*(C`pthread_atfork\*(C'\fR which is even faster). |
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443 | .Sp |
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444 | The big advantage of this flag is that you can forget about fork (and |
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445 | forget about forgetting to tell libev about forking) when you use this |
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446 | flag. |
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447 | .Sp |
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448 | This flag setting cannot be overriden or specified in the \f(CW\*(C`LIBEV_FLAGS\*(C'\fR |
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449 | environment variable. |
350 | .ie n .IP """EVBACKEND_SELECT"" (value 1, portable select backend)" 4 |
450 | .ie n .IP """EVBACKEND_SELECT"" (value 1, portable select backend)" 4 |
351 | .el .IP "\f(CWEVBACKEND_SELECT\fR (value 1, portable select backend)" 4 |
451 | .el .IP "\f(CWEVBACKEND_SELECT\fR (value 1, portable select backend)" 4 |
352 | .IX Item "EVBACKEND_SELECT (value 1, portable select backend)" |
452 | .IX Item "EVBACKEND_SELECT (value 1, portable select backend)" |
353 | This is your standard \fIselect\fR\|(2) backend. Not \fIcompletely\fR standard, as |
453 | This is your standard \fIselect\fR\|(2) backend. Not \fIcompletely\fR standard, as |
354 | libev tries to roll its own fd_set with no limits on the number of fds, |
454 | libev tries to roll its own fd_set with no limits on the number of fds, |
355 | but if that fails, expect a fairly low limit on the number of fds when |
455 | but if that fails, expect a fairly low limit on the number of fds when |
356 | using this backend. It doesn't scale too well (O(highest_fd)), but its usually |
456 | using this backend. It doesn't scale too well (O(highest_fd)), but its |
357 | the fastest backend for a low number of fds. |
457 | usually the fastest backend for a low number of (low\-numbered :) fds. |
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458 | .Sp |
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459 | To get good performance out of this backend you need a high amount of |
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460 | parallelity (most of the file descriptors should be busy). If you are |
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461 | writing a server, you should \f(CW\*(C`accept ()\*(C'\fR in a loop to accept as many |
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462 | connections as possible during one iteration. You might also want to have |
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463 | a look at \f(CW\*(C`ev_set_io_collect_interval ()\*(C'\fR to increase the amount of |
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464 | readyness notifications you get per iteration. |
358 | .ie n .IP """EVBACKEND_POLL"" (value 2, poll backend, available everywhere except on windows)" 4 |
465 | .ie n .IP """EVBACKEND_POLL"" (value 2, poll backend, available everywhere except on windows)" 4 |
359 | .el .IP "\f(CWEVBACKEND_POLL\fR (value 2, poll backend, available everywhere except on windows)" 4 |
466 | .el .IP "\f(CWEVBACKEND_POLL\fR (value 2, poll backend, available everywhere except on windows)" 4 |
360 | .IX Item "EVBACKEND_POLL (value 2, poll backend, available everywhere except on windows)" |
467 | .IX Item "EVBACKEND_POLL (value 2, poll backend, available everywhere except on windows)" |
361 | And this is your standard \fIpoll\fR\|(2) backend. It's more complicated than |
468 | And this is your standard \fIpoll\fR\|(2) backend. It's more complicated |
362 | select, but handles sparse fds better and has no artificial limit on the |
469 | than select, but handles sparse fds better and has no artificial |
363 | number of fds you can use (except it will slow down considerably with a |
470 | limit on the number of fds you can use (except it will slow down |
364 | lot of inactive fds). It scales similarly to select, i.e. O(total_fds). |
471 | considerably with a lot of inactive fds). It scales similarly to select, |
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472 | i.e. O(total_fds). See the entry for \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR, above, for |
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473 | performance tips. |
365 | .ie n .IP """EVBACKEND_EPOLL"" (value 4, Linux)" 4 |
474 | .ie n .IP """EVBACKEND_EPOLL"" (value 4, Linux)" 4 |
366 | .el .IP "\f(CWEVBACKEND_EPOLL\fR (value 4, Linux)" 4 |
475 | .el .IP "\f(CWEVBACKEND_EPOLL\fR (value 4, Linux)" 4 |
367 | .IX Item "EVBACKEND_EPOLL (value 4, Linux)" |
476 | .IX Item "EVBACKEND_EPOLL (value 4, Linux)" |
368 | For few fds, this backend is a bit little slower than poll and select, |
477 | For few fds, this backend is a bit little slower than poll and select, |
369 | but it scales phenomenally better. While poll and select usually scale like |
478 | but it scales phenomenally better. While poll and select usually scale |
370 | O(total_fds) where n is the total number of fds (or the highest fd), epoll scales |
479 | like O(total_fds) where n is the total number of fds (or the highest fd), |
371 | either O(1) or O(active_fds). |
480 | epoll scales either O(1) or O(active_fds). The epoll design has a number |
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481 | of shortcomings, such as silently dropping events in some hard-to-detect |
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482 | cases and rewiring a syscall per fd change, no fork support and bad |
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483 | support for dup. |
372 | .Sp |
484 | .Sp |
373 | While stopping and starting an I/O watcher in the same iteration will |
485 | While stopping, setting and starting an I/O watcher in the same iteration |
374 | result in some caching, there is still a syscall per such incident |
486 | will result in some caching, there is still a syscall per such incident |
375 | (because the fd could point to a different file description now), so its |
487 | (because the fd could point to a different file description now), so its |
376 | best to avoid that. Also, \fIdup()\fRed file descriptors might not work very |
488 | best to avoid that. Also, \f(CW\*(C`dup ()\*(C'\fR'ed file descriptors might not work |
377 | well if you register events for both fds. |
489 | very well if you register events for both fds. |
378 | .Sp |
490 | .Sp |
379 | Please note that epoll sometimes generates spurious notifications, so you |
491 | Please note that epoll sometimes generates spurious notifications, so you |
380 | need to use non-blocking I/O or other means to avoid blocking when no data |
492 | need to use non-blocking I/O or other means to avoid blocking when no data |
381 | (or space) is available. |
493 | (or space) is available. |
|
|
494 | .Sp |
|
|
495 | Best performance from this backend is achieved by not unregistering all |
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|
496 | watchers for a file descriptor until it has been closed, if possible, i.e. |
|
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497 | keep at least one watcher active per fd at all times. |
|
|
498 | .Sp |
|
|
499 | While nominally embeddeble in other event loops, this feature is broken in |
|
|
500 | all kernel versions tested so far. |
382 | .ie n .IP """EVBACKEND_KQUEUE"" (value 8, most \s-1BSD\s0 clones)" 4 |
501 | .ie n .IP """EVBACKEND_KQUEUE"" (value 8, most \s-1BSD\s0 clones)" 4 |
383 | .el .IP "\f(CWEVBACKEND_KQUEUE\fR (value 8, most \s-1BSD\s0 clones)" 4 |
502 | .el .IP "\f(CWEVBACKEND_KQUEUE\fR (value 8, most \s-1BSD\s0 clones)" 4 |
384 | .IX Item "EVBACKEND_KQUEUE (value 8, most BSD clones)" |
503 | .IX Item "EVBACKEND_KQUEUE (value 8, most BSD clones)" |
385 | Kqueue deserves special mention, as at the time of this writing, it |
504 | Kqueue deserves special mention, as at the time of this writing, it |
386 | was broken on all BSDs except NetBSD (usually it doesn't work with |
505 | was broken on all BSDs except NetBSD (usually it doesn't work reliably |
387 | anything but sockets and pipes, except on Darwin, where of course its |
506 | with anything but sockets and pipes, except on Darwin, where of course |
388 | completely useless). For this reason its not being \*(L"autodetected\*(R" |
507 | it's completely useless). For this reason it's not being \*(L"autodetected\*(R" |
389 | unless you explicitly specify it explicitly in the flags (i.e. using |
508 | unless you explicitly specify it explicitly in the flags (i.e. using |
390 | \&\f(CW\*(C`EVBACKEND_KQUEUE\*(C'\fR). |
509 | \&\f(CW\*(C`EVBACKEND_KQUEUE\*(C'\fR) or libev was compiled on a known-to-be-good (\-enough) |
|
|
510 | system like NetBSD. |
|
|
511 | .Sp |
|
|
512 | You still can embed kqueue into a normal poll or select backend and use it |
|
|
513 | only for sockets (after having made sure that sockets work with kqueue on |
|
|
514 | the target platform). See \f(CW\*(C`ev_embed\*(C'\fR watchers for more info. |
391 | .Sp |
515 | .Sp |
392 | It scales in the same way as the epoll backend, but the interface to the |
516 | It scales in the same way as the epoll backend, but the interface to the |
393 | kernel is more efficient (which says nothing about its actual speed, of |
517 | kernel is more efficient (which says nothing about its actual speed, of |
394 | course). While starting and stopping an I/O watcher does not cause an |
518 | course). While stopping, setting and starting an I/O watcher does never |
395 | extra syscall as with epoll, it still adds up to four event changes per |
519 | cause an extra syscall as with \f(CW\*(C`EVBACKEND_EPOLL\*(C'\fR, it still adds up to |
396 | incident, so its best to avoid that. |
520 | two event changes per incident, support for \f(CW\*(C`fork ()\*(C'\fR is very bad and it |
|
|
521 | drops fds silently in similarly hard-to-detect cases. |
|
|
522 | .Sp |
|
|
523 | This backend usually performs well under most conditions. |
|
|
524 | .Sp |
|
|
525 | While nominally embeddable in other event loops, this doesn't work |
|
|
526 | everywhere, so you might need to test for this. And since it is broken |
|
|
527 | almost everywhere, you should only use it when you have a lot of sockets |
|
|
528 | (for which it usually works), by embedding it into another event loop |
|
|
529 | (e.g. \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR or \f(CW\*(C`EVBACKEND_POLL\*(C'\fR) and using it only for |
|
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530 | sockets. |
397 | .ie n .IP """EVBACKEND_DEVPOLL"" (value 16, Solaris 8)" 4 |
531 | .ie n .IP """EVBACKEND_DEVPOLL"" (value 16, Solaris 8)" 4 |
398 | .el .IP "\f(CWEVBACKEND_DEVPOLL\fR (value 16, Solaris 8)" 4 |
532 | .el .IP "\f(CWEVBACKEND_DEVPOLL\fR (value 16, Solaris 8)" 4 |
399 | .IX Item "EVBACKEND_DEVPOLL (value 16, Solaris 8)" |
533 | .IX Item "EVBACKEND_DEVPOLL (value 16, Solaris 8)" |
400 | This is not implemented yet (and might never be). |
534 | This is not implemented yet (and might never be, unless you send me an |
|
|
535 | implementation). According to reports, \f(CW\*(C`/dev/poll\*(C'\fR only supports sockets |
|
|
536 | and is not embeddable, which would limit the usefulness of this backend |
|
|
537 | immensely. |
401 | .ie n .IP """EVBACKEND_PORT"" (value 32, Solaris 10)" 4 |
538 | .ie n .IP """EVBACKEND_PORT"" (value 32, Solaris 10)" 4 |
402 | .el .IP "\f(CWEVBACKEND_PORT\fR (value 32, Solaris 10)" 4 |
539 | .el .IP "\f(CWEVBACKEND_PORT\fR (value 32, Solaris 10)" 4 |
403 | .IX Item "EVBACKEND_PORT (value 32, Solaris 10)" |
540 | .IX Item "EVBACKEND_PORT (value 32, Solaris 10)" |
404 | This uses the Solaris 10 port mechanism. As with everything on Solaris, |
541 | This uses the Solaris 10 event port mechanism. As with everything on Solaris, |
405 | it's really slow, but it still scales very well (O(active_fds)). |
542 | it's really slow, but it still scales very well (O(active_fds)). |
406 | .Sp |
543 | .Sp |
407 | Please note that solaris ports can result in a lot of spurious |
544 | Please note that solaris event ports can deliver a lot of spurious |
408 | notifications, so you need to use non-blocking I/O or other means to avoid |
545 | notifications, so you need to use non-blocking I/O or other means to avoid |
409 | blocking when no data (or space) is available. |
546 | blocking when no data (or space) is available. |
|
|
547 | .Sp |
|
|
548 | While this backend scales well, it requires one system call per active |
|
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549 | file descriptor per loop iteration. For small and medium numbers of file |
|
|
550 | descriptors a \*(L"slow\*(R" \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR or \f(CW\*(C`EVBACKEND_POLL\*(C'\fR backend |
|
|
551 | might perform better. |
410 | .ie n .IP """EVBACKEND_ALL""" 4 |
552 | .ie n .IP """EVBACKEND_ALL""" 4 |
411 | .el .IP "\f(CWEVBACKEND_ALL\fR" 4 |
553 | .el .IP "\f(CWEVBACKEND_ALL\fR" 4 |
412 | .IX Item "EVBACKEND_ALL" |
554 | .IX Item "EVBACKEND_ALL" |
413 | Try all backends (even potentially broken ones that wouldn't be tried |
555 | Try all backends (even potentially broken ones that wouldn't be tried |
414 | with \f(CW\*(C`EVFLAG_AUTO\*(C'\fR). Since this is a mask, you can do stuff such as |
556 | with \f(CW\*(C`EVFLAG_AUTO\*(C'\fR). Since this is a mask, you can do stuff such as |
415 | \&\f(CW\*(C`EVBACKEND_ALL & ~EVBACKEND_KQUEUE\*(C'\fR. |
557 | \&\f(CW\*(C`EVBACKEND_ALL & ~EVBACKEND_KQUEUE\*(C'\fR. |
|
|
558 | .Sp |
|
|
559 | It is definitely not recommended to use this flag. |
416 | .RE |
560 | .RE |
417 | .RS 4 |
561 | .RS 4 |
418 | .Sp |
562 | .Sp |
419 | If one or more of these are ored into the flags value, then only these |
563 | If one or more of these are ored into the flags value, then only these |
420 | backends will be tried (in the reverse order as given here). If none are |
564 | backends will be tried (in the reverse order as given here). If none are |
… | |
… | |
448 | Similar to \f(CW\*(C`ev_default_loop\*(C'\fR, but always creates a new event loop that is |
592 | Similar to \f(CW\*(C`ev_default_loop\*(C'\fR, but always creates a new event loop that is |
449 | always distinct from the default loop. Unlike the default loop, it cannot |
593 | always distinct from the default loop. Unlike the default loop, it cannot |
450 | handle signal and child watchers, and attempts to do so will be greeted by |
594 | handle signal and child watchers, and attempts to do so will be greeted by |
451 | undefined behaviour (or a failed assertion if assertions are enabled). |
595 | undefined behaviour (or a failed assertion if assertions are enabled). |
452 | .Sp |
596 | .Sp |
453 | Example: try to create a event loop that uses epoll and nothing else. |
597 | Example: Try to create a event loop that uses epoll and nothing else. |
454 | .Sp |
598 | .Sp |
455 | .Vb 3 |
599 | .Vb 3 |
456 | \& struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
600 | \& struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
457 | \& if (!epoller) |
601 | \& if (!epoller) |
458 | \& fatal ("no epoll found here, maybe it hides under your chair"); |
602 | \& fatal ("no epoll found here, maybe it hides under your chair"); |
… | |
… | |
462 | Destroys the default loop again (frees all memory and kernel state |
606 | Destroys the default loop again (frees all memory and kernel state |
463 | etc.). None of the active event watchers will be stopped in the normal |
607 | etc.). None of the active event watchers will be stopped in the normal |
464 | sense, so e.g. \f(CW\*(C`ev_is_active\*(C'\fR might still return true. It is your |
608 | sense, so e.g. \f(CW\*(C`ev_is_active\*(C'\fR might still return true. It is your |
465 | responsibility to either stop all watchers cleanly yoursef \fIbefore\fR |
609 | responsibility to either stop all watchers cleanly yoursef \fIbefore\fR |
466 | calling this function, or cope with the fact afterwards (which is usually |
610 | calling this function, or cope with the fact afterwards (which is usually |
467 | the easiest thing, youc na just ignore the watchers and/or \f(CW\*(C`free ()\*(C'\fR them |
611 | the easiest thing, you can just ignore the watchers and/or \f(CW\*(C`free ()\*(C'\fR them |
468 | for example). |
612 | for example). |
|
|
613 | .Sp |
|
|
614 | Note that certain global state, such as signal state, will not be freed by |
|
|
615 | this function, and related watchers (such as signal and child watchers) |
|
|
616 | would need to be stopped manually. |
|
|
617 | .Sp |
|
|
618 | In general it is not advisable to call this function except in the |
|
|
619 | rare occasion where you really need to free e.g. the signal handling |
|
|
620 | pipe fds. If you need dynamically allocated loops it is better to use |
|
|
621 | \&\f(CW\*(C`ev_loop_new\*(C'\fR and \f(CW\*(C`ev_loop_destroy\*(C'\fR). |
469 | .IP "ev_loop_destroy (loop)" 4 |
622 | .IP "ev_loop_destroy (loop)" 4 |
470 | .IX Item "ev_loop_destroy (loop)" |
623 | .IX Item "ev_loop_destroy (loop)" |
471 | Like \f(CW\*(C`ev_default_destroy\*(C'\fR, but destroys an event loop created by an |
624 | Like \f(CW\*(C`ev_default_destroy\*(C'\fR, but destroys an event loop created by an |
472 | earlier call to \f(CW\*(C`ev_loop_new\*(C'\fR. |
625 | earlier call to \f(CW\*(C`ev_loop_new\*(C'\fR. |
473 | .IP "ev_default_fork ()" 4 |
626 | .IP "ev_default_fork ()" 4 |
… | |
… | |
495 | .IP "ev_loop_fork (loop)" 4 |
648 | .IP "ev_loop_fork (loop)" 4 |
496 | .IX Item "ev_loop_fork (loop)" |
649 | .IX Item "ev_loop_fork (loop)" |
497 | Like \f(CW\*(C`ev_default_fork\*(C'\fR, but acts on an event loop created by |
650 | Like \f(CW\*(C`ev_default_fork\*(C'\fR, but acts on an event loop created by |
498 | \&\f(CW\*(C`ev_loop_new\*(C'\fR. Yes, you have to call this on every allocated event loop |
651 | \&\f(CW\*(C`ev_loop_new\*(C'\fR. Yes, you have to call this on every allocated event loop |
499 | after fork, and how you do this is entirely your own problem. |
652 | after fork, and how you do this is entirely your own problem. |
|
|
653 | .IP "unsigned int ev_loop_count (loop)" 4 |
|
|
654 | .IX Item "unsigned int ev_loop_count (loop)" |
|
|
655 | Returns the count of loop iterations for the loop, which is identical to |
|
|
656 | the number of times libev did poll for new events. It starts at \f(CW0\fR and |
|
|
657 | happily wraps around with enough iterations. |
|
|
658 | .Sp |
|
|
659 | This value can sometimes be useful as a generation counter of sorts (it |
|
|
660 | \&\*(L"ticks\*(R" the number of loop iterations), as it roughly corresponds with |
|
|
661 | \&\f(CW\*(C`ev_prepare\*(C'\fR and \f(CW\*(C`ev_check\*(C'\fR calls. |
500 | .IP "unsigned int ev_backend (loop)" 4 |
662 | .IP "unsigned int ev_backend (loop)" 4 |
501 | .IX Item "unsigned int ev_backend (loop)" |
663 | .IX Item "unsigned int ev_backend (loop)" |
502 | Returns one of the \f(CW\*(C`EVBACKEND_*\*(C'\fR flags indicating the event backend in |
664 | Returns one of the \f(CW\*(C`EVBACKEND_*\*(C'\fR flags indicating the event backend in |
503 | use. |
665 | use. |
504 | .IP "ev_tstamp ev_now (loop)" 4 |
666 | .IP "ev_tstamp ev_now (loop)" 4 |
505 | .IX Item "ev_tstamp ev_now (loop)" |
667 | .IX Item "ev_tstamp ev_now (loop)" |
506 | Returns the current \*(L"event loop time\*(R", which is the time the event loop |
668 | Returns the current \*(L"event loop time\*(R", which is the time the event loop |
507 | received events and started processing them. This timestamp does not |
669 | received events and started processing them. This timestamp does not |
508 | change as long as callbacks are being processed, and this is also the base |
670 | change as long as callbacks are being processed, and this is also the base |
509 | time used for relative timers. You can treat it as the timestamp of the |
671 | time used for relative timers. You can treat it as the timestamp of the |
510 | event occuring (or more correctly, libev finding out about it). |
672 | event occurring (or more correctly, libev finding out about it). |
511 | .IP "ev_loop (loop, int flags)" 4 |
673 | .IP "ev_loop (loop, int flags)" 4 |
512 | .IX Item "ev_loop (loop, int flags)" |
674 | .IX Item "ev_loop (loop, int flags)" |
513 | Finally, this is it, the event handler. This function usually is called |
675 | Finally, this is it, the event handler. This function usually is called |
514 | after you initialised all your watchers and you want to start handling |
676 | after you initialised all your watchers and you want to start handling |
515 | events. |
677 | events. |
… | |
… | |
535 | libev watchers. However, a pair of \f(CW\*(C`ev_prepare\*(C'\fR/\f(CW\*(C`ev_check\*(C'\fR watchers is |
697 | libev watchers. However, a pair of \f(CW\*(C`ev_prepare\*(C'\fR/\f(CW\*(C`ev_check\*(C'\fR watchers is |
536 | usually a better approach for this kind of thing. |
698 | usually a better approach for this kind of thing. |
537 | .Sp |
699 | .Sp |
538 | Here are the gory details of what \f(CW\*(C`ev_loop\*(C'\fR does: |
700 | Here are the gory details of what \f(CW\*(C`ev_loop\*(C'\fR does: |
539 | .Sp |
701 | .Sp |
540 | .Vb 18 |
702 | .Vb 19 |
|
|
703 | \& - Before the first iteration, call any pending watchers. |
541 | \& * If there are no active watchers (reference count is zero), return. |
704 | \& * If there are no active watchers (reference count is zero), return. |
542 | \& - Queue prepare watchers and then call all outstanding watchers. |
705 | \& - Queue all prepare watchers and then call all outstanding watchers. |
543 | \& - If we have been forked, recreate the kernel state. |
706 | \& - If we have been forked, recreate the kernel state. |
544 | \& - Update the kernel state with all outstanding changes. |
707 | \& - Update the kernel state with all outstanding changes. |
545 | \& - Update the "event loop time". |
708 | \& - Update the "event loop time". |
546 | \& - Calculate for how long to block. |
709 | \& - Calculate for how long to block. |
547 | \& - Block the process, waiting for any events. |
710 | \& - Block the process, waiting for any events. |
… | |
… | |
556 | \& be handled here by queueing them when their watcher gets executed. |
719 | \& be handled here by queueing them when their watcher gets executed. |
557 | \& - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
720 | \& - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
558 | \& were used, return, otherwise continue with step *. |
721 | \& were used, return, otherwise continue with step *. |
559 | .Ve |
722 | .Ve |
560 | .Sp |
723 | .Sp |
561 | Example: queue some jobs and then loop until no events are outsanding |
724 | Example: Queue some jobs and then loop until no events are outsanding |
562 | anymore. |
725 | anymore. |
563 | .Sp |
726 | .Sp |
564 | .Vb 4 |
727 | .Vb 4 |
565 | \& ... queue jobs here, make sure they register event watchers as long |
728 | \& ... queue jobs here, make sure they register event watchers as long |
566 | \& ... as they still have work to do (even an idle watcher will do..) |
729 | \& ... as they still have work to do (even an idle watcher will do..) |
… | |
… | |
588 | visible to the libev user and should not keep \f(CW\*(C`ev_loop\*(C'\fR from exiting if |
751 | visible to the libev user and should not keep \f(CW\*(C`ev_loop\*(C'\fR from exiting if |
589 | no event watchers registered by it are active. It is also an excellent |
752 | no event watchers registered by it are active. It is also an excellent |
590 | way to do this for generic recurring timers or from within third-party |
753 | way to do this for generic recurring timers or from within third-party |
591 | libraries. Just remember to \fIunref after start\fR and \fIref before stop\fR. |
754 | libraries. Just remember to \fIunref after start\fR and \fIref before stop\fR. |
592 | .Sp |
755 | .Sp |
593 | Example: create a signal watcher, but keep it from keeping \f(CW\*(C`ev_loop\*(C'\fR |
756 | Example: Create a signal watcher, but keep it from keeping \f(CW\*(C`ev_loop\*(C'\fR |
594 | running when nothing else is active. |
757 | running when nothing else is active. |
595 | .Sp |
758 | .Sp |
596 | .Vb 4 |
759 | .Vb 4 |
597 | \& struct dv_signal exitsig; |
760 | \& struct ev_signal exitsig; |
598 | \& ev_signal_init (&exitsig, sig_cb, SIGINT); |
761 | \& ev_signal_init (&exitsig, sig_cb, SIGINT); |
599 | \& ev_signal_start (myloop, &exitsig); |
762 | \& ev_signal_start (loop, &exitsig); |
600 | \& evf_unref (myloop); |
763 | \& evf_unref (loop); |
601 | .Ve |
764 | .Ve |
602 | .Sp |
765 | .Sp |
603 | Example: for some weird reason, unregister the above signal handler again. |
766 | Example: For some weird reason, unregister the above signal handler again. |
604 | .Sp |
767 | .Sp |
605 | .Vb 2 |
768 | .Vb 2 |
606 | \& ev_ref (myloop); |
769 | \& ev_ref (loop); |
607 | \& ev_signal_stop (myloop, &exitsig); |
770 | \& ev_signal_stop (loop, &exitsig); |
608 | .Ve |
771 | .Ve |
|
|
772 | .IP "ev_set_io_collect_interval (loop, ev_tstamp interval)" 4 |
|
|
773 | .IX Item "ev_set_io_collect_interval (loop, ev_tstamp interval)" |
|
|
774 | .PD 0 |
|
|
775 | .IP "ev_set_timeout_collect_interval (loop, ev_tstamp interval)" 4 |
|
|
776 | .IX Item "ev_set_timeout_collect_interval (loop, ev_tstamp interval)" |
|
|
777 | .PD |
|
|
778 | These advanced functions influence the time that libev will spend waiting |
|
|
779 | for events. Both are by default \f(CW0\fR, meaning that libev will try to |
|
|
780 | invoke timer/periodic callbacks and I/O callbacks with minimum latency. |
|
|
781 | .Sp |
|
|
782 | Setting these to a higher value (the \f(CW\*(C`interval\*(C'\fR \fImust\fR be >= \f(CW0\fR) |
|
|
783 | allows libev to delay invocation of I/O and timer/periodic callbacks to |
|
|
784 | increase efficiency of loop iterations. |
|
|
785 | .Sp |
|
|
786 | The background is that sometimes your program runs just fast enough to |
|
|
787 | handle one (or very few) event(s) per loop iteration. While this makes |
|
|
788 | the program responsive, it also wastes a lot of \s-1CPU\s0 time to poll for new |
|
|
789 | events, especially with backends like \f(CW\*(C`select ()\*(C'\fR which have a high |
|
|
790 | overhead for the actual polling but can deliver many events at once. |
|
|
791 | .Sp |
|
|
792 | By setting a higher \fIio collect interval\fR you allow libev to spend more |
|
|
793 | time collecting I/O events, so you can handle more events per iteration, |
|
|
794 | at the cost of increasing latency. Timeouts (both \f(CW\*(C`ev_periodic\*(C'\fR and |
|
|
795 | \&\f(CW\*(C`ev_timer\*(C'\fR) will be not affected. Setting this to a non-null value will |
|
|
796 | introduce an additional \f(CW\*(C`ev_sleep ()\*(C'\fR call into most loop iterations. |
|
|
797 | .Sp |
|
|
798 | Likewise, by setting a higher \fItimeout collect interval\fR you allow libev |
|
|
799 | to spend more time collecting timeouts, at the expense of increased |
|
|
800 | latency (the watcher callback will be called later). \f(CW\*(C`ev_io\*(C'\fR watchers |
|
|
801 | will not be affected. Setting this to a non-null value will not introduce |
|
|
802 | any overhead in libev. |
|
|
803 | .Sp |
|
|
804 | Many (busy) programs can usually benefit by setting the io collect |
|
|
805 | interval to a value near \f(CW0.1\fR or so, which is often enough for |
|
|
806 | interactive servers (of course not for games), likewise for timeouts. It |
|
|
807 | usually doesn't make much sense to set it to a lower value than \f(CW0.01\fR, |
|
|
808 | as this approsaches the timing granularity of most systems. |
609 | .SH "ANATOMY OF A WATCHER" |
809 | .SH "ANATOMY OF A WATCHER" |
610 | .IX Header "ANATOMY OF A WATCHER" |
810 | .IX Header "ANATOMY OF A WATCHER" |
611 | A watcher is a structure that you create and register to record your |
811 | A watcher is a structure that you create and register to record your |
612 | interest in some event. For instance, if you want to wait for \s-1STDIN\s0 to |
812 | interest in some event. For instance, if you want to wait for \s-1STDIN\s0 to |
613 | become readable, you would create an \f(CW\*(C`ev_io\*(C'\fR watcher for that: |
813 | become readable, you would create an \f(CW\*(C`ev_io\*(C'\fR watcher for that: |
… | |
… | |
684 | The signal specified in the \f(CW\*(C`ev_signal\*(C'\fR watcher has been received by a thread. |
884 | The signal specified in the \f(CW\*(C`ev_signal\*(C'\fR watcher has been received by a thread. |
685 | .ie n .IP """EV_CHILD""" 4 |
885 | .ie n .IP """EV_CHILD""" 4 |
686 | .el .IP "\f(CWEV_CHILD\fR" 4 |
886 | .el .IP "\f(CWEV_CHILD\fR" 4 |
687 | .IX Item "EV_CHILD" |
887 | .IX Item "EV_CHILD" |
688 | The pid specified in the \f(CW\*(C`ev_child\*(C'\fR watcher has received a status change. |
888 | The pid specified in the \f(CW\*(C`ev_child\*(C'\fR watcher has received a status change. |
|
|
889 | .ie n .IP """EV_STAT""" 4 |
|
|
890 | .el .IP "\f(CWEV_STAT\fR" 4 |
|
|
891 | .IX Item "EV_STAT" |
|
|
892 | The path specified in the \f(CW\*(C`ev_stat\*(C'\fR watcher changed its attributes somehow. |
689 | .ie n .IP """EV_IDLE""" 4 |
893 | .ie n .IP """EV_IDLE""" 4 |
690 | .el .IP "\f(CWEV_IDLE\fR" 4 |
894 | .el .IP "\f(CWEV_IDLE\fR" 4 |
691 | .IX Item "EV_IDLE" |
895 | .IX Item "EV_IDLE" |
692 | The \f(CW\*(C`ev_idle\*(C'\fR watcher has determined that you have nothing better to do. |
896 | The \f(CW\*(C`ev_idle\*(C'\fR watcher has determined that you have nothing better to do. |
693 | .ie n .IP """EV_PREPARE""" 4 |
897 | .ie n .IP """EV_PREPARE""" 4 |
… | |
… | |
703 | \&\f(CW\*(C`ev_loop\*(C'\fR has gathered them, but before it invokes any callbacks for any |
907 | \&\f(CW\*(C`ev_loop\*(C'\fR has gathered them, but before it invokes any callbacks for any |
704 | received events. Callbacks of both watcher types can start and stop as |
908 | received events. Callbacks of both watcher types can start and stop as |
705 | many watchers as they want, and all of them will be taken into account |
909 | many watchers as they want, and all of them will be taken into account |
706 | (for example, a \f(CW\*(C`ev_prepare\*(C'\fR watcher might start an idle watcher to keep |
910 | (for example, a \f(CW\*(C`ev_prepare\*(C'\fR watcher might start an idle watcher to keep |
707 | \&\f(CW\*(C`ev_loop\*(C'\fR from blocking). |
911 | \&\f(CW\*(C`ev_loop\*(C'\fR from blocking). |
|
|
912 | .ie n .IP """EV_EMBED""" 4 |
|
|
913 | .el .IP "\f(CWEV_EMBED\fR" 4 |
|
|
914 | .IX Item "EV_EMBED" |
|
|
915 | The embedded event loop specified in the \f(CW\*(C`ev_embed\*(C'\fR watcher needs attention. |
|
|
916 | .ie n .IP """EV_FORK""" 4 |
|
|
917 | .el .IP "\f(CWEV_FORK\fR" 4 |
|
|
918 | .IX Item "EV_FORK" |
|
|
919 | The event loop has been resumed in the child process after fork (see |
|
|
920 | \&\f(CW\*(C`ev_fork\*(C'\fR). |
708 | .ie n .IP """EV_ERROR""" 4 |
921 | .ie n .IP """EV_ERROR""" 4 |
709 | .el .IP "\f(CWEV_ERROR\fR" 4 |
922 | .el .IP "\f(CWEV_ERROR\fR" 4 |
710 | .IX Item "EV_ERROR" |
923 | .IX Item "EV_ERROR" |
711 | An unspecified error has occured, the watcher has been stopped. This might |
924 | An unspecified error has occured, the watcher has been stopped. This might |
712 | happen because the watcher could not be properly started because libev |
925 | happen because the watcher could not be properly started because libev |
… | |
… | |
777 | .IP "bool ev_is_pending (ev_TYPE *watcher)" 4 |
990 | .IP "bool ev_is_pending (ev_TYPE *watcher)" 4 |
778 | .IX Item "bool ev_is_pending (ev_TYPE *watcher)" |
991 | .IX Item "bool ev_is_pending (ev_TYPE *watcher)" |
779 | Returns a true value iff the watcher is pending, (i.e. it has outstanding |
992 | Returns a true value iff the watcher is pending, (i.e. it has outstanding |
780 | events but its callback has not yet been invoked). As long as a watcher |
993 | events but its callback has not yet been invoked). As long as a watcher |
781 | is pending (but not active) you must not call an init function on it (but |
994 | is pending (but not active) you must not call an init function on it (but |
782 | \&\f(CW\*(C`ev_TYPE_set\*(C'\fR is safe) and you must make sure the watcher is available to |
995 | \&\f(CW\*(C`ev_TYPE_set\*(C'\fR is safe), you must not change its priority, and you must |
783 | libev (e.g. you cnanot \f(CW\*(C`free ()\*(C'\fR it). |
996 | make sure the watcher is available to libev (e.g. you cannot \f(CW\*(C`free ()\*(C'\fR |
|
|
997 | it). |
784 | .IP "callback = ev_cb (ev_TYPE *watcher)" 4 |
998 | .IP "callback ev_cb (ev_TYPE *watcher)" 4 |
785 | .IX Item "callback = ev_cb (ev_TYPE *watcher)" |
999 | .IX Item "callback ev_cb (ev_TYPE *watcher)" |
786 | Returns the callback currently set on the watcher. |
1000 | Returns the callback currently set on the watcher. |
787 | .IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 |
1001 | .IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 |
788 | .IX Item "ev_cb_set (ev_TYPE *watcher, callback)" |
1002 | .IX Item "ev_cb_set (ev_TYPE *watcher, callback)" |
789 | Change the callback. You can change the callback at virtually any time |
1003 | Change the callback. You can change the callback at virtually any time |
790 | (modulo threads). |
1004 | (modulo threads). |
|
|
1005 | .IP "ev_set_priority (ev_TYPE *watcher, priority)" 4 |
|
|
1006 | .IX Item "ev_set_priority (ev_TYPE *watcher, priority)" |
|
|
1007 | .PD 0 |
|
|
1008 | .IP "int ev_priority (ev_TYPE *watcher)" 4 |
|
|
1009 | .IX Item "int ev_priority (ev_TYPE *watcher)" |
|
|
1010 | .PD |
|
|
1011 | Set and query the priority of the watcher. The priority is a small |
|
|
1012 | integer between \f(CW\*(C`EV_MAXPRI\*(C'\fR (default: \f(CW2\fR) and \f(CW\*(C`EV_MINPRI\*(C'\fR |
|
|
1013 | (default: \f(CW\*(C`\-2\*(C'\fR). Pending watchers with higher priority will be invoked |
|
|
1014 | before watchers with lower priority, but priority will not keep watchers |
|
|
1015 | from being executed (except for \f(CW\*(C`ev_idle\*(C'\fR watchers). |
|
|
1016 | .Sp |
|
|
1017 | This means that priorities are \fIonly\fR used for ordering callback |
|
|
1018 | invocation after new events have been received. This is useful, for |
|
|
1019 | example, to reduce latency after idling, or more often, to bind two |
|
|
1020 | watchers on the same event and make sure one is called first. |
|
|
1021 | .Sp |
|
|
1022 | If you need to suppress invocation when higher priority events are pending |
|
|
1023 | you need to look at \f(CW\*(C`ev_idle\*(C'\fR watchers, which provide this functionality. |
|
|
1024 | .Sp |
|
|
1025 | You \fImust not\fR change the priority of a watcher as long as it is active or |
|
|
1026 | pending. |
|
|
1027 | .Sp |
|
|
1028 | The default priority used by watchers when no priority has been set is |
|
|
1029 | always \f(CW0\fR, which is supposed to not be too high and not be too low :). |
|
|
1030 | .Sp |
|
|
1031 | Setting a priority outside the range of \f(CW\*(C`EV_MINPRI\*(C'\fR to \f(CW\*(C`EV_MAXPRI\*(C'\fR is |
|
|
1032 | fine, as long as you do not mind that the priority value you query might |
|
|
1033 | or might not have been adjusted to be within valid range. |
|
|
1034 | .IP "ev_invoke (loop, ev_TYPE *watcher, int revents)" 4 |
|
|
1035 | .IX Item "ev_invoke (loop, ev_TYPE *watcher, int revents)" |
|
|
1036 | Invoke the \f(CW\*(C`watcher\*(C'\fR with the given \f(CW\*(C`loop\*(C'\fR and \f(CW\*(C`revents\*(C'\fR. Neither |
|
|
1037 | \&\f(CW\*(C`loop\*(C'\fR nor \f(CW\*(C`revents\*(C'\fR need to be valid as long as the watcher callback |
|
|
1038 | can deal with that fact. |
|
|
1039 | .IP "int ev_clear_pending (loop, ev_TYPE *watcher)" 4 |
|
|
1040 | .IX Item "int ev_clear_pending (loop, ev_TYPE *watcher)" |
|
|
1041 | If the watcher is pending, this function returns clears its pending status |
|
|
1042 | and returns its \f(CW\*(C`revents\*(C'\fR bitset (as if its callback was invoked). If the |
|
|
1043 | watcher isn't pending it does nothing and returns \f(CW0\fR. |
791 | .Sh "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0" |
1044 | .Sh "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0" |
792 | .IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER" |
1045 | .IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER" |
793 | Each watcher has, by default, a member \f(CW\*(C`void *data\*(C'\fR that you can change |
1046 | Each watcher has, by default, a member \f(CW\*(C`void *data\*(C'\fR that you can change |
794 | and read at any time, libev will completely ignore it. This can be used |
1047 | and read at any time, libev will completely ignore it. This can be used |
795 | to associate arbitrary data with your watcher. If you need more data and |
1048 | to associate arbitrary data with your watcher. If you need more data and |
… | |
… | |
816 | \& struct my_io *w = (struct my_io *)w_; |
1069 | \& struct my_io *w = (struct my_io *)w_; |
817 | \& ... |
1070 | \& ... |
818 | \& } |
1071 | \& } |
819 | .Ve |
1072 | .Ve |
820 | .PP |
1073 | .PP |
821 | More interesting and less C\-conformant ways of catsing your callback type |
1074 | More interesting and less C\-conformant ways of casting your callback type |
822 | have been omitted.... |
1075 | instead have been omitted. |
|
|
1076 | .PP |
|
|
1077 | Another common scenario is having some data structure with multiple |
|
|
1078 | watchers: |
|
|
1079 | .PP |
|
|
1080 | .Vb 6 |
|
|
1081 | \& struct my_biggy |
|
|
1082 | \& { |
|
|
1083 | \& int some_data; |
|
|
1084 | \& ev_timer t1; |
|
|
1085 | \& ev_timer t2; |
|
|
1086 | \& } |
|
|
1087 | .Ve |
|
|
1088 | .PP |
|
|
1089 | In this case getting the pointer to \f(CW\*(C`my_biggy\*(C'\fR is a bit more complicated, |
|
|
1090 | you need to use \f(CW\*(C`offsetof\*(C'\fR: |
|
|
1091 | .PP |
|
|
1092 | .Vb 1 |
|
|
1093 | \& #include <stddef.h> |
|
|
1094 | .Ve |
|
|
1095 | .PP |
|
|
1096 | .Vb 6 |
|
|
1097 | \& static void |
|
|
1098 | \& t1_cb (EV_P_ struct ev_timer *w, int revents) |
|
|
1099 | \& { |
|
|
1100 | \& struct my_biggy big = (struct my_biggy * |
|
|
1101 | \& (((char *)w) - offsetof (struct my_biggy, t1)); |
|
|
1102 | \& } |
|
|
1103 | .Ve |
|
|
1104 | .PP |
|
|
1105 | .Vb 6 |
|
|
1106 | \& static void |
|
|
1107 | \& t2_cb (EV_P_ struct ev_timer *w, int revents) |
|
|
1108 | \& { |
|
|
1109 | \& struct my_biggy big = (struct my_biggy * |
|
|
1110 | \& (((char *)w) - offsetof (struct my_biggy, t2)); |
|
|
1111 | \& } |
|
|
1112 | .Ve |
823 | .SH "WATCHER TYPES" |
1113 | .SH "WATCHER TYPES" |
824 | .IX Header "WATCHER TYPES" |
1114 | .IX Header "WATCHER TYPES" |
825 | This section describes each watcher in detail, but will not repeat |
1115 | This section describes each watcher in detail, but will not repeat |
826 | information given in the last section. |
1116 | information given in the last section. Any initialisation/set macros, |
|
|
1117 | functions and members specific to the watcher type are explained. |
|
|
1118 | .PP |
|
|
1119 | Members are additionally marked with either \fI[read\-only]\fR, meaning that, |
|
|
1120 | while the watcher is active, you can look at the member and expect some |
|
|
1121 | sensible content, but you must not modify it (you can modify it while the |
|
|
1122 | watcher is stopped to your hearts content), or \fI[read\-write]\fR, which |
|
|
1123 | means you can expect it to have some sensible content while the watcher |
|
|
1124 | is active, but you can also modify it. Modifying it may not do something |
|
|
1125 | sensible or take immediate effect (or do anything at all), but libev will |
|
|
1126 | not crash or malfunction in any way. |
827 | .ie n .Sh """ev_io"" \- is this file descriptor readable or writable?" |
1127 | .ie n .Sh """ev_io"" \- is this file descriptor readable or writable?" |
828 | .el .Sh "\f(CWev_io\fP \- is this file descriptor readable or writable?" |
1128 | .el .Sh "\f(CWev_io\fP \- is this file descriptor readable or writable?" |
829 | .IX Subsection "ev_io - is this file descriptor readable or writable?" |
1129 | .IX Subsection "ev_io - is this file descriptor readable or writable?" |
830 | I/O watchers check whether a file descriptor is readable or writable |
1130 | I/O watchers check whether a file descriptor is readable or writable |
831 | in each iteration of the event loop, or, more precisely, when reading |
1131 | in each iteration of the event loop, or, more precisely, when reading |
… | |
… | |
838 | In general you can register as many read and/or write event watchers per |
1138 | In general you can register as many read and/or write event watchers per |
839 | fd as you want (as long as you don't confuse yourself). Setting all file |
1139 | fd as you want (as long as you don't confuse yourself). Setting all file |
840 | descriptors to non-blocking mode is also usually a good idea (but not |
1140 | descriptors to non-blocking mode is also usually a good idea (but not |
841 | required if you know what you are doing). |
1141 | required if you know what you are doing). |
842 | .PP |
1142 | .PP |
843 | You have to be careful with dup'ed file descriptors, though. Some backends |
|
|
844 | (the linux epoll backend is a notable example) cannot handle dup'ed file |
|
|
845 | descriptors correctly if you register interest in two or more fds pointing |
|
|
846 | to the same underlying file/socket/etc. description (that is, they share |
|
|
847 | the same underlying \*(L"file open\*(R"). |
|
|
848 | .PP |
|
|
849 | If you must do this, then force the use of a known-to-be-good backend |
1143 | If you must do this, then force the use of a known-to-be-good backend |
850 | (at the time of this writing, this includes only \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR and |
1144 | (at the time of this writing, this includes only \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR and |
851 | \&\f(CW\*(C`EVBACKEND_POLL\*(C'\fR). |
1145 | \&\f(CW\*(C`EVBACKEND_POLL\*(C'\fR). |
852 | .PP |
1146 | .PP |
853 | Another thing you have to watch out for is that it is quite easy to |
1147 | Another thing you have to watch out for is that it is quite easy to |
… | |
… | |
859 | it is best to always use non-blocking I/O: An extra \f(CW\*(C`read\*(C'\fR(2) returning |
1153 | it is best to always use non-blocking I/O: An extra \f(CW\*(C`read\*(C'\fR(2) returning |
860 | \&\f(CW\*(C`EAGAIN\*(C'\fR is far preferable to a program hanging until some data arrives. |
1154 | \&\f(CW\*(C`EAGAIN\*(C'\fR is far preferable to a program hanging until some data arrives. |
861 | .PP |
1155 | .PP |
862 | If you cannot run the fd in non-blocking mode (for example you should not |
1156 | If you cannot run the fd in non-blocking mode (for example you should not |
863 | play around with an Xlib connection), then you have to seperately re-test |
1157 | play around with an Xlib connection), then you have to seperately re-test |
864 | wether a file descriptor is really ready with a known-to-be good interface |
1158 | whether a file descriptor is really ready with a known-to-be good interface |
865 | such as poll (fortunately in our Xlib example, Xlib already does this on |
1159 | such as poll (fortunately in our Xlib example, Xlib already does this on |
866 | its own, so its quite safe to use). |
1160 | its own, so its quite safe to use). |
|
|
1161 | .PP |
|
|
1162 | \fIThe special problem of disappearing file descriptors\fR |
|
|
1163 | .IX Subsection "The special problem of disappearing file descriptors" |
|
|
1164 | .PP |
|
|
1165 | Some backends (e.g. kqueue, epoll) need to be told about closing a file |
|
|
1166 | descriptor (either by calling \f(CW\*(C`close\*(C'\fR explicitly or by any other means, |
|
|
1167 | such as \f(CW\*(C`dup\*(C'\fR). The reason is that you register interest in some file |
|
|
1168 | descriptor, but when it goes away, the operating system will silently drop |
|
|
1169 | this interest. If another file descriptor with the same number then is |
|
|
1170 | registered with libev, there is no efficient way to see that this is, in |
|
|
1171 | fact, a different file descriptor. |
|
|
1172 | .PP |
|
|
1173 | To avoid having to explicitly tell libev about such cases, libev follows |
|
|
1174 | the following policy: Each time \f(CW\*(C`ev_io_set\*(C'\fR is being called, libev |
|
|
1175 | will assume that this is potentially a new file descriptor, otherwise |
|
|
1176 | it is assumed that the file descriptor stays the same. That means that |
|
|
1177 | you \fIhave\fR to call \f(CW\*(C`ev_io_set\*(C'\fR (or \f(CW\*(C`ev_io_init\*(C'\fR) when you change the |
|
|
1178 | descriptor even if the file descriptor number itself did not change. |
|
|
1179 | .PP |
|
|
1180 | This is how one would do it normally anyway, the important point is that |
|
|
1181 | the libev application should not optimise around libev but should leave |
|
|
1182 | optimisations to libev. |
|
|
1183 | .PP |
|
|
1184 | \fIThe special problem of dup'ed file descriptors\fR |
|
|
1185 | .IX Subsection "The special problem of dup'ed file descriptors" |
|
|
1186 | .PP |
|
|
1187 | Some backends (e.g. epoll), cannot register events for file descriptors, |
|
|
1188 | but only events for the underlying file descriptions. That means when you |
|
|
1189 | have \f(CW\*(C`dup ()\*(C'\fR'ed file descriptors or weirder constellations, and register |
|
|
1190 | events for them, only one file descriptor might actually receive events. |
|
|
1191 | .PP |
|
|
1192 | There is no workaround possible except not registering events |
|
|
1193 | for potentially \f(CW\*(C`dup ()\*(C'\fR'ed file descriptors, or to resort to |
|
|
1194 | \&\f(CW\*(C`EVBACKEND_SELECT\*(C'\fR or \f(CW\*(C`EVBACKEND_POLL\*(C'\fR. |
|
|
1195 | .PP |
|
|
1196 | \fIThe special problem of fork\fR |
|
|
1197 | .IX Subsection "The special problem of fork" |
|
|
1198 | .PP |
|
|
1199 | Some backends (epoll, kqueue) do not support \f(CW\*(C`fork ()\*(C'\fR at all or exhibit |
|
|
1200 | useless behaviour. Libev fully supports fork, but needs to be told about |
|
|
1201 | it in the child. |
|
|
1202 | .PP |
|
|
1203 | To support fork in your programs, you either have to call |
|
|
1204 | \&\f(CW\*(C`ev_default_fork ()\*(C'\fR or \f(CW\*(C`ev_loop_fork ()\*(C'\fR after a fork in the child, |
|
|
1205 | enable \f(CW\*(C`EVFLAG_FORKCHECK\*(C'\fR, or resort to \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR or |
|
|
1206 | \&\f(CW\*(C`EVBACKEND_POLL\*(C'\fR. |
|
|
1207 | .PP |
|
|
1208 | \fIWatcher-Specific Functions\fR |
|
|
1209 | .IX Subsection "Watcher-Specific Functions" |
867 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
1210 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
868 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
1211 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
869 | .PD 0 |
1212 | .PD 0 |
870 | .IP "ev_io_set (ev_io *, int fd, int events)" 4 |
1213 | .IP "ev_io_set (ev_io *, int fd, int events)" 4 |
871 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
1214 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
872 | .PD |
1215 | .PD |
873 | Configures an \f(CW\*(C`ev_io\*(C'\fR watcher. The \f(CW\*(C`fd\*(C'\fR is the file descriptor to |
1216 | Configures an \f(CW\*(C`ev_io\*(C'\fR watcher. The \f(CW\*(C`fd\*(C'\fR is the file descriptor to |
874 | rceeive events for and events is either \f(CW\*(C`EV_READ\*(C'\fR, \f(CW\*(C`EV_WRITE\*(C'\fR or |
1217 | rceeive events for and events is either \f(CW\*(C`EV_READ\*(C'\fR, \f(CW\*(C`EV_WRITE\*(C'\fR or |
875 | \&\f(CW\*(C`EV_READ | EV_WRITE\*(C'\fR to receive the given events. |
1218 | \&\f(CW\*(C`EV_READ | EV_WRITE\*(C'\fR to receive the given events. |
|
|
1219 | .IP "int fd [read\-only]" 4 |
|
|
1220 | .IX Item "int fd [read-only]" |
|
|
1221 | The file descriptor being watched. |
|
|
1222 | .IP "int events [read\-only]" 4 |
|
|
1223 | .IX Item "int events [read-only]" |
|
|
1224 | The events being watched. |
876 | .PP |
1225 | .PP |
877 | Example: call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well |
1226 | Example: Call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well |
878 | readable, but only once. Since it is likely line\-buffered, you could |
1227 | readable, but only once. Since it is likely line\-buffered, you could |
879 | attempt to read a whole line in the callback: |
1228 | attempt to read a whole line in the callback. |
880 | .PP |
1229 | .PP |
881 | .Vb 6 |
1230 | .Vb 6 |
882 | \& static void |
1231 | \& static void |
883 | \& stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
1232 | \& stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
884 | \& { |
1233 | \& { |
… | |
… | |
918 | .Ve |
1267 | .Ve |
919 | .PP |
1268 | .PP |
920 | The callback is guarenteed to be invoked only when its timeout has passed, |
1269 | The callback is guarenteed to be invoked only when its timeout has passed, |
921 | but if multiple timers become ready during the same loop iteration then |
1270 | but if multiple timers become ready during the same loop iteration then |
922 | order of execution is undefined. |
1271 | order of execution is undefined. |
|
|
1272 | .PP |
|
|
1273 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1274 | .IX Subsection "Watcher-Specific Functions and Data Members" |
923 | .IP "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" 4 |
1275 | .IP "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" 4 |
924 | .IX Item "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" |
1276 | .IX Item "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" |
925 | .PD 0 |
1277 | .PD 0 |
926 | .IP "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)" 4 |
1278 | .IP "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)" 4 |
927 | .IX Item "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)" |
1279 | .IX Item "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)" |
… | |
… | |
939 | .IP "ev_timer_again (loop)" 4 |
1291 | .IP "ev_timer_again (loop)" 4 |
940 | .IX Item "ev_timer_again (loop)" |
1292 | .IX Item "ev_timer_again (loop)" |
941 | This will act as if the timer timed out and restart it again if it is |
1293 | This will act as if the timer timed out and restart it again if it is |
942 | repeating. The exact semantics are: |
1294 | repeating. The exact semantics are: |
943 | .Sp |
1295 | .Sp |
|
|
1296 | If the timer is pending, its pending status is cleared. |
|
|
1297 | .Sp |
944 | If the timer is started but nonrepeating, stop it. |
1298 | If the timer is started but nonrepeating, stop it (as if it timed out). |
945 | .Sp |
1299 | .Sp |
946 | If the timer is repeating, either start it if necessary (with the repeat |
1300 | If the timer is repeating, either start it if necessary (with the |
947 | value), or reset the running timer to the repeat value. |
1301 | \&\f(CW\*(C`repeat\*(C'\fR value), or reset the running timer to the \f(CW\*(C`repeat\*(C'\fR value. |
948 | .Sp |
1302 | .Sp |
949 | This sounds a bit complicated, but here is a useful and typical |
1303 | This sounds a bit complicated, but here is a useful and typical |
950 | example: Imagine you have a tcp connection and you want a so-called idle |
1304 | example: Imagine you have a tcp connection and you want a so-called idle |
951 | timeout, that is, you want to be called when there have been, say, 60 |
1305 | timeout, that is, you want to be called when there have been, say, 60 |
952 | seconds of inactivity on the socket. The easiest way to do this is to |
1306 | seconds of inactivity on the socket. The easiest way to do this is to |
953 | configure an \f(CW\*(C`ev_timer\*(C'\fR with after=repeat=60 and calling ev_timer_again each |
1307 | configure an \f(CW\*(C`ev_timer\*(C'\fR with a \f(CW\*(C`repeat\*(C'\fR value of \f(CW60\fR and then call |
954 | time you successfully read or write some data. If you go into an idle |
1308 | \&\f(CW\*(C`ev_timer_again\*(C'\fR each time you successfully read or write some data. If |
955 | state where you do not expect data to travel on the socket, you can stop |
1309 | you go into an idle state where you do not expect data to travel on the |
956 | the timer, and again will automatically restart it if need be. |
1310 | socket, you can \f(CW\*(C`ev_timer_stop\*(C'\fR the timer, and \f(CW\*(C`ev_timer_again\*(C'\fR will |
|
|
1311 | automatically restart it if need be. |
|
|
1312 | .Sp |
|
|
1313 | That means you can ignore the \f(CW\*(C`after\*(C'\fR value and \f(CW\*(C`ev_timer_start\*(C'\fR |
|
|
1314 | altogether and only ever use the \f(CW\*(C`repeat\*(C'\fR value and \f(CW\*(C`ev_timer_again\*(C'\fR: |
|
|
1315 | .Sp |
|
|
1316 | .Vb 8 |
|
|
1317 | \& ev_timer_init (timer, callback, 0., 5.); |
|
|
1318 | \& ev_timer_again (loop, timer); |
|
|
1319 | \& ... |
|
|
1320 | \& timer->again = 17.; |
|
|
1321 | \& ev_timer_again (loop, timer); |
|
|
1322 | \& ... |
|
|
1323 | \& timer->again = 10.; |
|
|
1324 | \& ev_timer_again (loop, timer); |
|
|
1325 | .Ve |
|
|
1326 | .Sp |
|
|
1327 | This is more slightly efficient then stopping/starting the timer each time |
|
|
1328 | you want to modify its timeout value. |
|
|
1329 | .IP "ev_tstamp repeat [read\-write]" 4 |
|
|
1330 | .IX Item "ev_tstamp repeat [read-write]" |
|
|
1331 | The current \f(CW\*(C`repeat\*(C'\fR value. Will be used each time the watcher times out |
|
|
1332 | or \f(CW\*(C`ev_timer_again\*(C'\fR is called and determines the next timeout (if any), |
|
|
1333 | which is also when any modifications are taken into account. |
957 | .PP |
1334 | .PP |
958 | Example: create a timer that fires after 60 seconds. |
1335 | Example: Create a timer that fires after 60 seconds. |
959 | .PP |
1336 | .PP |
960 | .Vb 5 |
1337 | .Vb 5 |
961 | \& static void |
1338 | \& static void |
962 | \& one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1339 | \& one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
963 | \& { |
1340 | \& { |
… | |
… | |
969 | \& struct ev_timer mytimer; |
1346 | \& struct ev_timer mytimer; |
970 | \& ev_timer_init (&mytimer, one_minute_cb, 60., 0.); |
1347 | \& ev_timer_init (&mytimer, one_minute_cb, 60., 0.); |
971 | \& ev_timer_start (loop, &mytimer); |
1348 | \& ev_timer_start (loop, &mytimer); |
972 | .Ve |
1349 | .Ve |
973 | .PP |
1350 | .PP |
974 | Example: create a timeout timer that times out after 10 seconds of |
1351 | Example: Create a timeout timer that times out after 10 seconds of |
975 | inactivity. |
1352 | inactivity. |
976 | .PP |
1353 | .PP |
977 | .Vb 5 |
1354 | .Vb 5 |
978 | \& static void |
1355 | \& static void |
979 | \& timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1356 | \& timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
… | |
… | |
1004 | but on wallclock time (absolute time). You can tell a periodic watcher |
1381 | but on wallclock time (absolute time). You can tell a periodic watcher |
1005 | to trigger \*(L"at\*(R" some specific point in time. For example, if you tell a |
1382 | to trigger \*(L"at\*(R" some specific point in time. For example, if you tell a |
1006 | periodic watcher to trigger in 10 seconds (by specifiying e.g. \f(CW\*(C`ev_now () |
1383 | periodic watcher to trigger in 10 seconds (by specifiying e.g. \f(CW\*(C`ev_now () |
1007 | + 10.\*(C'\fR) and then reset your system clock to the last year, then it will |
1384 | + 10.\*(C'\fR) and then reset your system clock to the last year, then it will |
1008 | take a year to trigger the event (unlike an \f(CW\*(C`ev_timer\*(C'\fR, which would trigger |
1385 | take a year to trigger the event (unlike an \f(CW\*(C`ev_timer\*(C'\fR, which would trigger |
1009 | roughly 10 seconds later and of course not if you reset your system time |
1386 | roughly 10 seconds later). |
1010 | again). |
|
|
1011 | .PP |
1387 | .PP |
1012 | They can also be used to implement vastly more complex timers, such as |
1388 | They can also be used to implement vastly more complex timers, such as |
1013 | triggering an event on eahc midnight, local time. |
1389 | triggering an event on each midnight, local time or other, complicated, |
|
|
1390 | rules. |
1014 | .PP |
1391 | .PP |
1015 | As with timers, the callback is guarenteed to be invoked only when the |
1392 | As with timers, the callback is guarenteed to be invoked only when the |
1016 | time (\f(CW\*(C`at\*(C'\fR) has been passed, but if multiple periodic timers become ready |
1393 | time (\f(CW\*(C`at\*(C'\fR) has been passed, but if multiple periodic timers become ready |
1017 | during the same loop iteration then order of execution is undefined. |
1394 | during the same loop iteration then order of execution is undefined. |
|
|
1395 | .PP |
|
|
1396 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1397 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1018 | .IP "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" 4 |
1398 | .IP "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" 4 |
1019 | .IX Item "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" |
1399 | .IX Item "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" |
1020 | .PD 0 |
1400 | .PD 0 |
1021 | .IP "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" 4 |
1401 | .IP "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" 4 |
1022 | .IX Item "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" |
1402 | .IX Item "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" |
1023 | .PD |
1403 | .PD |
1024 | Lots of arguments, lets sort it out... There are basically three modes of |
1404 | Lots of arguments, lets sort it out... There are basically three modes of |
1025 | operation, and we will explain them from simplest to complex: |
1405 | operation, and we will explain them from simplest to complex: |
1026 | .RS 4 |
1406 | .RS 4 |
1027 | .IP "* absolute timer (interval = reschedule_cb = 0)" 4 |
1407 | .IP "* absolute timer (at = time, interval = reschedule_cb = 0)" 4 |
1028 | .IX Item "absolute timer (interval = reschedule_cb = 0)" |
1408 | .IX Item "absolute timer (at = time, interval = reschedule_cb = 0)" |
1029 | In this configuration the watcher triggers an event at the wallclock time |
1409 | In this configuration the watcher triggers an event at the wallclock time |
1030 | \&\f(CW\*(C`at\*(C'\fR and doesn't repeat. It will not adjust when a time jump occurs, |
1410 | \&\f(CW\*(C`at\*(C'\fR and doesn't repeat. It will not adjust when a time jump occurs, |
1031 | that is, if it is to be run at January 1st 2011 then it will run when the |
1411 | that is, if it is to be run at January 1st 2011 then it will run when the |
1032 | system time reaches or surpasses this time. |
1412 | system time reaches or surpasses this time. |
1033 | .IP "* non-repeating interval timer (interval > 0, reschedule_cb = 0)" 4 |
1413 | .IP "* non-repeating interval timer (at = offset, interval > 0, reschedule_cb = 0)" 4 |
1034 | .IX Item "non-repeating interval timer (interval > 0, reschedule_cb = 0)" |
1414 | .IX Item "non-repeating interval timer (at = offset, interval > 0, reschedule_cb = 0)" |
1035 | In this mode the watcher will always be scheduled to time out at the next |
1415 | In this mode the watcher will always be scheduled to time out at the next |
1036 | \&\f(CW\*(C`at + N * interval\*(C'\fR time (for some integer N) and then repeat, regardless |
1416 | \&\f(CW\*(C`at + N * interval\*(C'\fR time (for some integer N, which can also be negative) |
1037 | of any time jumps. |
1417 | and then repeat, regardless of any time jumps. |
1038 | .Sp |
1418 | .Sp |
1039 | This can be used to create timers that do not drift with respect to system |
1419 | This can be used to create timers that do not drift with respect to system |
1040 | time: |
1420 | time: |
1041 | .Sp |
1421 | .Sp |
1042 | .Vb 1 |
1422 | .Vb 1 |
… | |
… | |
1049 | by 3600. |
1429 | by 3600. |
1050 | .Sp |
1430 | .Sp |
1051 | Another way to think about it (for the mathematically inclined) is that |
1431 | Another way to think about it (for the mathematically inclined) is that |
1052 | \&\f(CW\*(C`ev_periodic\*(C'\fR will try to run the callback in this mode at the next possible |
1432 | \&\f(CW\*(C`ev_periodic\*(C'\fR will try to run the callback in this mode at the next possible |
1053 | time where \f(CW\*(C`time = at (mod interval)\*(C'\fR, regardless of any time jumps. |
1433 | time where \f(CW\*(C`time = at (mod interval)\*(C'\fR, regardless of any time jumps. |
|
|
1434 | .Sp |
|
|
1435 | For numerical stability it is preferable that the \f(CW\*(C`at\*(C'\fR value is near |
|
|
1436 | \&\f(CW\*(C`ev_now ()\*(C'\fR (the current time), but there is no range requirement for |
|
|
1437 | this value. |
1054 | .IP "* manual reschedule mode (reschedule_cb = callback)" 4 |
1438 | .IP "* manual reschedule mode (at and interval ignored, reschedule_cb = callback)" 4 |
1055 | .IX Item "manual reschedule mode (reschedule_cb = callback)" |
1439 | .IX Item "manual reschedule mode (at and interval ignored, reschedule_cb = callback)" |
1056 | In this mode the values for \f(CW\*(C`interval\*(C'\fR and \f(CW\*(C`at\*(C'\fR are both being |
1440 | In this mode the values for \f(CW\*(C`interval\*(C'\fR and \f(CW\*(C`at\*(C'\fR are both being |
1057 | ignored. Instead, each time the periodic watcher gets scheduled, the |
1441 | ignored. Instead, each time the periodic watcher gets scheduled, the |
1058 | reschedule callback will be called with the watcher as first, and the |
1442 | reschedule callback will be called with the watcher as first, and the |
1059 | current time as second argument. |
1443 | current time as second argument. |
1060 | .Sp |
1444 | .Sp |
1061 | \&\s-1NOTE:\s0 \fIThis callback \s-1MUST\s0 \s-1NOT\s0 stop or destroy any periodic watcher, |
1445 | \&\s-1NOTE:\s0 \fIThis callback \s-1MUST\s0 \s-1NOT\s0 stop or destroy any periodic watcher, |
1062 | ever, or make any event loop modifications\fR. If you need to stop it, |
1446 | ever, or make any event loop modifications\fR. If you need to stop it, |
1063 | return \f(CW\*(C`now + 1e30\*(C'\fR (or so, fudge fudge) and stop it afterwards (e.g. by |
1447 | return \f(CW\*(C`now + 1e30\*(C'\fR (or so, fudge fudge) and stop it afterwards (e.g. by |
1064 | starting a prepare watcher). |
1448 | starting an \f(CW\*(C`ev_prepare\*(C'\fR watcher, which is legal). |
1065 | .Sp |
1449 | .Sp |
1066 | Its prototype is \f(CW\*(C`ev_tstamp (*reschedule_cb)(struct ev_periodic *w, |
1450 | Its prototype is \f(CW\*(C`ev_tstamp (*reschedule_cb)(struct ev_periodic *w, |
1067 | ev_tstamp now)\*(C'\fR, e.g.: |
1451 | ev_tstamp now)\*(C'\fR, e.g.: |
1068 | .Sp |
1452 | .Sp |
1069 | .Vb 4 |
1453 | .Vb 4 |
… | |
… | |
1093 | .IX Item "ev_periodic_again (loop, ev_periodic *)" |
1477 | .IX Item "ev_periodic_again (loop, ev_periodic *)" |
1094 | Simply stops and restarts the periodic watcher again. This is only useful |
1478 | Simply stops and restarts the periodic watcher again. This is only useful |
1095 | when you changed some parameters or the reschedule callback would return |
1479 | when you changed some parameters or the reschedule callback would return |
1096 | a different time than the last time it was called (e.g. in a crond like |
1480 | a different time than the last time it was called (e.g. in a crond like |
1097 | program when the crontabs have changed). |
1481 | program when the crontabs have changed). |
|
|
1482 | .IP "ev_tstamp offset [read\-write]" 4 |
|
|
1483 | .IX Item "ev_tstamp offset [read-write]" |
|
|
1484 | When repeating, this contains the offset value, otherwise this is the |
|
|
1485 | absolute point in time (the \f(CW\*(C`at\*(C'\fR value passed to \f(CW\*(C`ev_periodic_set\*(C'\fR). |
|
|
1486 | .Sp |
|
|
1487 | Can be modified any time, but changes only take effect when the periodic |
|
|
1488 | timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called. |
|
|
1489 | .IP "ev_tstamp interval [read\-write]" 4 |
|
|
1490 | .IX Item "ev_tstamp interval [read-write]" |
|
|
1491 | The current interval value. Can be modified any time, but changes only |
|
|
1492 | take effect when the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being |
|
|
1493 | called. |
|
|
1494 | .IP "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read\-write]" 4 |
|
|
1495 | .IX Item "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write]" |
|
|
1496 | The current reschedule callback, or \f(CW0\fR, if this functionality is |
|
|
1497 | switched off. Can be changed any time, but changes only take effect when |
|
|
1498 | the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called. |
|
|
1499 | .IP "ev_tstamp at [read\-only]" 4 |
|
|
1500 | .IX Item "ev_tstamp at [read-only]" |
|
|
1501 | When active, contains the absolute time that the watcher is supposed to |
|
|
1502 | trigger next. |
1098 | .PP |
1503 | .PP |
1099 | Example: call a callback every hour, or, more precisely, whenever the |
1504 | Example: Call a callback every hour, or, more precisely, whenever the |
1100 | system clock is divisible by 3600. The callback invocation times have |
1505 | system clock is divisible by 3600. The callback invocation times have |
1101 | potentially a lot of jittering, but good long-term stability. |
1506 | potentially a lot of jittering, but good long-term stability. |
1102 | .PP |
1507 | .PP |
1103 | .Vb 5 |
1508 | .Vb 5 |
1104 | \& static void |
1509 | \& static void |
… | |
… | |
1112 | \& struct ev_periodic hourly_tick; |
1517 | \& struct ev_periodic hourly_tick; |
1113 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); |
1518 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); |
1114 | \& ev_periodic_start (loop, &hourly_tick); |
1519 | \& ev_periodic_start (loop, &hourly_tick); |
1115 | .Ve |
1520 | .Ve |
1116 | .PP |
1521 | .PP |
1117 | Example: the same as above, but use a reschedule callback to do it: |
1522 | Example: The same as above, but use a reschedule callback to do it: |
1118 | .PP |
1523 | .PP |
1119 | .Vb 1 |
1524 | .Vb 1 |
1120 | \& #include <math.h> |
1525 | \& #include <math.h> |
1121 | .Ve |
1526 | .Ve |
1122 | .PP |
1527 | .PP |
… | |
… | |
1130 | .PP |
1535 | .PP |
1131 | .Vb 1 |
1536 | .Vb 1 |
1132 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); |
1537 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); |
1133 | .Ve |
1538 | .Ve |
1134 | .PP |
1539 | .PP |
1135 | Example: call a callback every hour, starting now: |
1540 | Example: Call a callback every hour, starting now: |
1136 | .PP |
1541 | .PP |
1137 | .Vb 4 |
1542 | .Vb 4 |
1138 | \& struct ev_periodic hourly_tick; |
1543 | \& struct ev_periodic hourly_tick; |
1139 | \& ev_periodic_init (&hourly_tick, clock_cb, |
1544 | \& ev_periodic_init (&hourly_tick, clock_cb, |
1140 | \& fmod (ev_now (loop), 3600.), 3600., 0); |
1545 | \& fmod (ev_now (loop), 3600.), 3600., 0); |
… | |
… | |
1152 | first watcher gets started will libev actually register a signal watcher |
1557 | first watcher gets started will libev actually register a signal watcher |
1153 | with the kernel (thus it coexists with your own signal handlers as long |
1558 | with the kernel (thus it coexists with your own signal handlers as long |
1154 | as you don't register any with libev). Similarly, when the last signal |
1559 | as you don't register any with libev). Similarly, when the last signal |
1155 | watcher for a signal is stopped libev will reset the signal handler to |
1560 | watcher for a signal is stopped libev will reset the signal handler to |
1156 | \&\s-1SIG_DFL\s0 (regardless of what it was set to before). |
1561 | \&\s-1SIG_DFL\s0 (regardless of what it was set to before). |
|
|
1562 | .PP |
|
|
1563 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1564 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1157 | .IP "ev_signal_init (ev_signal *, callback, int signum)" 4 |
1565 | .IP "ev_signal_init (ev_signal *, callback, int signum)" 4 |
1158 | .IX Item "ev_signal_init (ev_signal *, callback, int signum)" |
1566 | .IX Item "ev_signal_init (ev_signal *, callback, int signum)" |
1159 | .PD 0 |
1567 | .PD 0 |
1160 | .IP "ev_signal_set (ev_signal *, int signum)" 4 |
1568 | .IP "ev_signal_set (ev_signal *, int signum)" 4 |
1161 | .IX Item "ev_signal_set (ev_signal *, int signum)" |
1569 | .IX Item "ev_signal_set (ev_signal *, int signum)" |
1162 | .PD |
1570 | .PD |
1163 | Configures the watcher to trigger on the given signal number (usually one |
1571 | Configures the watcher to trigger on the given signal number (usually one |
1164 | of the \f(CW\*(C`SIGxxx\*(C'\fR constants). |
1572 | of the \f(CW\*(C`SIGxxx\*(C'\fR constants). |
|
|
1573 | .IP "int signum [read\-only]" 4 |
|
|
1574 | .IX Item "int signum [read-only]" |
|
|
1575 | The signal the watcher watches out for. |
1165 | .ie n .Sh """ev_child"" \- watch out for process status changes" |
1576 | .ie n .Sh """ev_child"" \- watch out for process status changes" |
1166 | .el .Sh "\f(CWev_child\fP \- watch out for process status changes" |
1577 | .el .Sh "\f(CWev_child\fP \- watch out for process status changes" |
1167 | .IX Subsection "ev_child - watch out for process status changes" |
1578 | .IX Subsection "ev_child - watch out for process status changes" |
1168 | Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to |
1579 | Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to |
1169 | some child status changes (most typically when a child of yours dies). |
1580 | some child status changes (most typically when a child of yours dies). |
|
|
1581 | .PP |
|
|
1582 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1583 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1170 | .IP "ev_child_init (ev_child *, callback, int pid)" 4 |
1584 | .IP "ev_child_init (ev_child *, callback, int pid)" 4 |
1171 | .IX Item "ev_child_init (ev_child *, callback, int pid)" |
1585 | .IX Item "ev_child_init (ev_child *, callback, int pid)" |
1172 | .PD 0 |
1586 | .PD 0 |
1173 | .IP "ev_child_set (ev_child *, int pid)" 4 |
1587 | .IP "ev_child_set (ev_child *, int pid)" 4 |
1174 | .IX Item "ev_child_set (ev_child *, int pid)" |
1588 | .IX Item "ev_child_set (ev_child *, int pid)" |
… | |
… | |
1177 | \&\fIany\fR process if \f(CW\*(C`pid\*(C'\fR is specified as \f(CW0\fR). The callback can look |
1591 | \&\fIany\fR process if \f(CW\*(C`pid\*(C'\fR is specified as \f(CW0\fR). The callback can look |
1178 | at the \f(CW\*(C`rstatus\*(C'\fR member of the \f(CW\*(C`ev_child\*(C'\fR watcher structure to see |
1592 | at the \f(CW\*(C`rstatus\*(C'\fR member of the \f(CW\*(C`ev_child\*(C'\fR watcher structure to see |
1179 | the status word (use the macros from \f(CW\*(C`sys/wait.h\*(C'\fR and see your systems |
1593 | the status word (use the macros from \f(CW\*(C`sys/wait.h\*(C'\fR and see your systems |
1180 | \&\f(CW\*(C`waitpid\*(C'\fR documentation). The \f(CW\*(C`rpid\*(C'\fR member contains the pid of the |
1594 | \&\f(CW\*(C`waitpid\*(C'\fR documentation). The \f(CW\*(C`rpid\*(C'\fR member contains the pid of the |
1181 | process causing the status change. |
1595 | process causing the status change. |
|
|
1596 | .IP "int pid [read\-only]" 4 |
|
|
1597 | .IX Item "int pid [read-only]" |
|
|
1598 | The process id this watcher watches out for, or \f(CW0\fR, meaning any process id. |
|
|
1599 | .IP "int rpid [read\-write]" 4 |
|
|
1600 | .IX Item "int rpid [read-write]" |
|
|
1601 | The process id that detected a status change. |
|
|
1602 | .IP "int rstatus [read\-write]" 4 |
|
|
1603 | .IX Item "int rstatus [read-write]" |
|
|
1604 | The process exit/trace status caused by \f(CW\*(C`rpid\*(C'\fR (see your systems |
|
|
1605 | \&\f(CW\*(C`waitpid\*(C'\fR and \f(CW\*(C`sys/wait.h\*(C'\fR documentation for details). |
1182 | .PP |
1606 | .PP |
1183 | Example: try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0. |
1607 | Example: Try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0. |
1184 | .PP |
1608 | .PP |
1185 | .Vb 5 |
1609 | .Vb 5 |
1186 | \& static void |
1610 | \& static void |
1187 | \& sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
1611 | \& sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
1188 | \& { |
1612 | \& { |
… | |
… | |
1193 | .Vb 3 |
1617 | .Vb 3 |
1194 | \& struct ev_signal signal_watcher; |
1618 | \& struct ev_signal signal_watcher; |
1195 | \& ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
1619 | \& ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
1196 | \& ev_signal_start (loop, &sigint_cb); |
1620 | \& ev_signal_start (loop, &sigint_cb); |
1197 | .Ve |
1621 | .Ve |
|
|
1622 | .ie n .Sh """ev_stat"" \- did the file attributes just change?" |
|
|
1623 | .el .Sh "\f(CWev_stat\fP \- did the file attributes just change?" |
|
|
1624 | .IX Subsection "ev_stat - did the file attributes just change?" |
|
|
1625 | This watches a filesystem path for attribute changes. That is, it calls |
|
|
1626 | \&\f(CW\*(C`stat\*(C'\fR regularly (or when the \s-1OS\s0 says it changed) and sees if it changed |
|
|
1627 | compared to the last time, invoking the callback if it did. |
|
|
1628 | .PP |
|
|
1629 | The path does not need to exist: changing from \*(L"path exists\*(R" to \*(L"path does |
|
|
1630 | not exist\*(R" is a status change like any other. The condition \*(L"path does |
|
|
1631 | not exist\*(R" is signified by the \f(CW\*(C`st_nlink\*(C'\fR field being zero (which is |
|
|
1632 | otherwise always forced to be at least one) and all the other fields of |
|
|
1633 | the stat buffer having unspecified contents. |
|
|
1634 | .PP |
|
|
1635 | The path \fIshould\fR be absolute and \fImust not\fR end in a slash. If it is |
|
|
1636 | relative and your working directory changes, the behaviour is undefined. |
|
|
1637 | .PP |
|
|
1638 | Since there is no standard to do this, the portable implementation simply |
|
|
1639 | calls \f(CW\*(C`stat (2)\*(C'\fR regularly on the path to see if it changed somehow. You |
|
|
1640 | can specify a recommended polling interval for this case. If you specify |
|
|
1641 | a polling interval of \f(CW0\fR (highly recommended!) then a \fIsuitable, |
|
|
1642 | unspecified default\fR value will be used (which you can expect to be around |
|
|
1643 | five seconds, although this might change dynamically). Libev will also |
|
|
1644 | impose a minimum interval which is currently around \f(CW0.1\fR, but thats |
|
|
1645 | usually overkill. |
|
|
1646 | .PP |
|
|
1647 | This watcher type is not meant for massive numbers of stat watchers, |
|
|
1648 | as even with OS-supported change notifications, this can be |
|
|
1649 | resource\-intensive. |
|
|
1650 | .PP |
|
|
1651 | At the time of this writing, only the Linux inotify interface is |
|
|
1652 | implemented (implementing kqueue support is left as an exercise for the |
|
|
1653 | reader). Inotify will be used to give hints only and should not change the |
|
|
1654 | semantics of \f(CW\*(C`ev_stat\*(C'\fR watchers, which means that libev sometimes needs |
|
|
1655 | to fall back to regular polling again even with inotify, but changes are |
|
|
1656 | usually detected immediately, and if the file exists there will be no |
|
|
1657 | polling. |
|
|
1658 | .PP |
|
|
1659 | \fIInotify\fR |
|
|
1660 | .IX Subsection "Inotify" |
|
|
1661 | .PP |
|
|
1662 | When \f(CW\*(C`inotify (7)\*(C'\fR support has been compiled into libev (generally only |
|
|
1663 | available on Linux) and present at runtime, it will be used to speed up |
|
|
1664 | change detection where possible. The inotify descriptor will be created lazily |
|
|
1665 | when the first \f(CW\*(C`ev_stat\*(C'\fR watcher is being started. |
|
|
1666 | .PP |
|
|
1667 | Inotify presense does not change the semantics of \f(CW\*(C`ev_stat\*(C'\fR watchers |
|
|
1668 | except that changes might be detected earlier, and in some cases, to avoid |
|
|
1669 | making regular \f(CW\*(C`stat\*(C'\fR calls. Even in the presense of inotify support |
|
|
1670 | there are many cases where libev has to resort to regular \f(CW\*(C`stat\*(C'\fR polling. |
|
|
1671 | .PP |
|
|
1672 | (There is no support for kqueue, as apparently it cannot be used to |
|
|
1673 | implement this functionality, due to the requirement of having a file |
|
|
1674 | descriptor open on the object at all times). |
|
|
1675 | .PP |
|
|
1676 | \fIThe special problem of stat time resolution\fR |
|
|
1677 | .IX Subsection "The special problem of stat time resolution" |
|
|
1678 | .PP |
|
|
1679 | The \f(CW\*(C`stat ()\*(C'\fR syscall only supports full-second resolution portably, and |
|
|
1680 | even on systems where the resolution is higher, many filesystems still |
|
|
1681 | only support whole seconds. |
|
|
1682 | .PP |
|
|
1683 | That means that, if the time is the only thing that changes, you might |
|
|
1684 | miss updates: on the first update, \f(CW\*(C`ev_stat\*(C'\fR detects a change and calls |
|
|
1685 | your callback, which does something. When there is another update within |
|
|
1686 | the same second, \f(CW\*(C`ev_stat\*(C'\fR will be unable to detect it. |
|
|
1687 | .PP |
|
|
1688 | The solution to this is to delay acting on a change for a second (or till |
|
|
1689 | the next second boundary), using a roughly one-second delay \f(CW\*(C`ev_timer\*(C'\fR |
|
|
1690 | (\f(CW\*(C`ev_timer_set (w, 0., 1.01); ev_timer_again (loop, w)\*(C'\fR). The \f(CW.01\fR |
|
|
1691 | is added to work around small timing inconsistencies of some operating |
|
|
1692 | systems. |
|
|
1693 | .PP |
|
|
1694 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1695 | .IX Subsection "Watcher-Specific Functions and Data Members" |
|
|
1696 | .IP "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" 4 |
|
|
1697 | .IX Item "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" |
|
|
1698 | .PD 0 |
|
|
1699 | .IP "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" 4 |
|
|
1700 | .IX Item "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" |
|
|
1701 | .PD |
|
|
1702 | Configures the watcher to wait for status changes of the given |
|
|
1703 | \&\f(CW\*(C`path\*(C'\fR. The \f(CW\*(C`interval\*(C'\fR is a hint on how quickly a change is expected to |
|
|
1704 | be detected and should normally be specified as \f(CW0\fR to let libev choose |
|
|
1705 | a suitable value. The memory pointed to by \f(CW\*(C`path\*(C'\fR must point to the same |
|
|
1706 | path for as long as the watcher is active. |
|
|
1707 | .Sp |
|
|
1708 | The callback will be receive \f(CW\*(C`EV_STAT\*(C'\fR when a change was detected, |
|
|
1709 | relative to the attributes at the time the watcher was started (or the |
|
|
1710 | last change was detected). |
|
|
1711 | .IP "ev_stat_stat (ev_stat *)" 4 |
|
|
1712 | .IX Item "ev_stat_stat (ev_stat *)" |
|
|
1713 | Updates the stat buffer immediately with new values. If you change the |
|
|
1714 | watched path in your callback, you could call this fucntion to avoid |
|
|
1715 | detecting this change (while introducing a race condition). Can also be |
|
|
1716 | useful simply to find out the new values. |
|
|
1717 | .IP "ev_statdata attr [read\-only]" 4 |
|
|
1718 | .IX Item "ev_statdata attr [read-only]" |
|
|
1719 | The most-recently detected attributes of the file. Although the type is of |
|
|
1720 | \&\f(CW\*(C`ev_statdata\*(C'\fR, this is usually the (or one of the) \f(CW\*(C`struct stat\*(C'\fR types |
|
|
1721 | suitable for your system. If the \f(CW\*(C`st_nlink\*(C'\fR member is \f(CW0\fR, then there |
|
|
1722 | was some error while \f(CW\*(C`stat\*(C'\fRing the file. |
|
|
1723 | .IP "ev_statdata prev [read\-only]" 4 |
|
|
1724 | .IX Item "ev_statdata prev [read-only]" |
|
|
1725 | The previous attributes of the file. The callback gets invoked whenever |
|
|
1726 | \&\f(CW\*(C`prev\*(C'\fR != \f(CW\*(C`attr\*(C'\fR. |
|
|
1727 | .IP "ev_tstamp interval [read\-only]" 4 |
|
|
1728 | .IX Item "ev_tstamp interval [read-only]" |
|
|
1729 | The specified interval. |
|
|
1730 | .IP "const char *path [read\-only]" 4 |
|
|
1731 | .IX Item "const char *path [read-only]" |
|
|
1732 | The filesystem path that is being watched. |
|
|
1733 | .PP |
|
|
1734 | \fIExamples\fR |
|
|
1735 | .IX Subsection "Examples" |
|
|
1736 | .PP |
|
|
1737 | Example: Watch \f(CW\*(C`/etc/passwd\*(C'\fR for attribute changes. |
|
|
1738 | .PP |
|
|
1739 | .Vb 15 |
|
|
1740 | \& static void |
|
|
1741 | \& passwd_cb (struct ev_loop *loop, ev_stat *w, int revents) |
|
|
1742 | \& { |
|
|
1743 | \& /* /etc/passwd changed in some way */ |
|
|
1744 | \& if (w->attr.st_nlink) |
|
|
1745 | \& { |
|
|
1746 | \& printf ("passwd current size %ld\en", (long)w->attr.st_size); |
|
|
1747 | \& printf ("passwd current atime %ld\en", (long)w->attr.st_mtime); |
|
|
1748 | \& printf ("passwd current mtime %ld\en", (long)w->attr.st_mtime); |
|
|
1749 | \& } |
|
|
1750 | \& else |
|
|
1751 | \& /* you shalt not abuse printf for puts */ |
|
|
1752 | \& puts ("wow, /etc/passwd is not there, expect problems. " |
|
|
1753 | \& "if this is windows, they already arrived\en"); |
|
|
1754 | \& } |
|
|
1755 | .Ve |
|
|
1756 | .PP |
|
|
1757 | .Vb 2 |
|
|
1758 | \& ... |
|
|
1759 | \& ev_stat passwd; |
|
|
1760 | .Ve |
|
|
1761 | .PP |
|
|
1762 | .Vb 2 |
|
|
1763 | \& ev_stat_init (&passwd, passwd_cb, "/etc/passwd", 0.); |
|
|
1764 | \& ev_stat_start (loop, &passwd); |
|
|
1765 | .Ve |
|
|
1766 | .PP |
|
|
1767 | Example: Like above, but additionally use a one-second delay so we do not |
|
|
1768 | miss updates (however, frequent updates will delay processing, too, so |
|
|
1769 | one might do the work both on \f(CW\*(C`ev_stat\*(C'\fR callback invocation \fIand\fR on |
|
|
1770 | \&\f(CW\*(C`ev_timer\*(C'\fR callback invocation). |
|
|
1771 | .PP |
|
|
1772 | .Vb 2 |
|
|
1773 | \& static ev_stat passwd; |
|
|
1774 | \& static ev_timer timer; |
|
|
1775 | .Ve |
|
|
1776 | .PP |
|
|
1777 | .Vb 4 |
|
|
1778 | \& static void |
|
|
1779 | \& timer_cb (EV_P_ ev_timer *w, int revents) |
|
|
1780 | \& { |
|
|
1781 | \& ev_timer_stop (EV_A_ w); |
|
|
1782 | .Ve |
|
|
1783 | .PP |
|
|
1784 | .Vb 2 |
|
|
1785 | \& /* now it's one second after the most recent passwd change */ |
|
|
1786 | \& } |
|
|
1787 | .Ve |
|
|
1788 | .PP |
|
|
1789 | .Vb 6 |
|
|
1790 | \& static void |
|
|
1791 | \& stat_cb (EV_P_ ev_stat *w, int revents) |
|
|
1792 | \& { |
|
|
1793 | \& /* reset the one-second timer */ |
|
|
1794 | \& ev_timer_again (EV_A_ &timer); |
|
|
1795 | \& } |
|
|
1796 | .Ve |
|
|
1797 | .PP |
|
|
1798 | .Vb 4 |
|
|
1799 | \& ... |
|
|
1800 | \& ev_stat_init (&passwd, stat_cb, "/etc/passwd", 0.); |
|
|
1801 | \& ev_stat_start (loop, &passwd); |
|
|
1802 | \& ev_timer_init (&timer, timer_cb, 0., 1.01); |
|
|
1803 | .Ve |
1198 | .ie n .Sh """ev_idle"" \- when you've got nothing better to do..." |
1804 | .ie n .Sh """ev_idle"" \- when you've got nothing better to do..." |
1199 | .el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do..." |
1805 | .el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do..." |
1200 | .IX Subsection "ev_idle - when you've got nothing better to do..." |
1806 | .IX Subsection "ev_idle - when you've got nothing better to do..." |
1201 | Idle watchers trigger events when there are no other events are pending |
1807 | Idle watchers trigger events when no other events of the same or higher |
1202 | (prepare, check and other idle watchers do not count). That is, as long |
1808 | priority are pending (prepare, check and other idle watchers do not |
1203 | as your process is busy handling sockets or timeouts (or even signals, |
1809 | count). |
1204 | imagine) it will not be triggered. But when your process is idle all idle |
1810 | .PP |
1205 | watchers are being called again and again, once per event loop iteration \- |
1811 | That is, as long as your process is busy handling sockets or timeouts |
|
|
1812 | (or even signals, imagine) of the same or higher priority it will not be |
|
|
1813 | triggered. But when your process is idle (or only lower-priority watchers |
|
|
1814 | are pending), the idle watchers are being called once per event loop |
1206 | until stopped, that is, or your process receives more events and becomes |
1815 | iteration \- until stopped, that is, or your process receives more events |
1207 | busy. |
1816 | and becomes busy again with higher priority stuff. |
1208 | .PP |
1817 | .PP |
1209 | The most noteworthy effect is that as long as any idle watchers are |
1818 | The most noteworthy effect is that as long as any idle watchers are |
1210 | active, the process will not block when waiting for new events. |
1819 | active, the process will not block when waiting for new events. |
1211 | .PP |
1820 | .PP |
1212 | Apart from keeping your process non-blocking (which is a useful |
1821 | Apart from keeping your process non-blocking (which is a useful |
1213 | effect on its own sometimes), idle watchers are a good place to do |
1822 | effect on its own sometimes), idle watchers are a good place to do |
1214 | \&\*(L"pseudo\-background processing\*(R", or delay processing stuff to after the |
1823 | \&\*(L"pseudo\-background processing\*(R", or delay processing stuff to after the |
1215 | event loop has handled all outstanding events. |
1824 | event loop has handled all outstanding events. |
|
|
1825 | .PP |
|
|
1826 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1827 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1216 | .IP "ev_idle_init (ev_signal *, callback)" 4 |
1828 | .IP "ev_idle_init (ev_signal *, callback)" 4 |
1217 | .IX Item "ev_idle_init (ev_signal *, callback)" |
1829 | .IX Item "ev_idle_init (ev_signal *, callback)" |
1218 | Initialises and configures the idle watcher \- it has no parameters of any |
1830 | Initialises and configures the idle watcher \- it has no parameters of any |
1219 | kind. There is a \f(CW\*(C`ev_idle_set\*(C'\fR macro, but using it is utterly pointless, |
1831 | kind. There is a \f(CW\*(C`ev_idle_set\*(C'\fR macro, but using it is utterly pointless, |
1220 | believe me. |
1832 | believe me. |
1221 | .PP |
1833 | .PP |
1222 | Example: dynamically allocate an \f(CW\*(C`ev_idle\*(C'\fR, start it, and in the |
1834 | Example: Dynamically allocate an \f(CW\*(C`ev_idle\*(C'\fR watcher, start it, and in the |
1223 | callback, free it. Alos, use no error checking, as usual. |
1835 | callback, free it. Also, use no error checking, as usual. |
1224 | .PP |
1836 | .PP |
1225 | .Vb 7 |
1837 | .Vb 7 |
1226 | \& static void |
1838 | \& static void |
1227 | \& idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
1839 | \& idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
1228 | \& { |
1840 | \& { |
… | |
… | |
1242 | .IX Subsection "ev_prepare and ev_check - customise your event loop!" |
1854 | .IX Subsection "ev_prepare and ev_check - customise your event loop!" |
1243 | Prepare and check watchers are usually (but not always) used in tandem: |
1855 | Prepare and check watchers are usually (but not always) used in tandem: |
1244 | prepare watchers get invoked before the process blocks and check watchers |
1856 | prepare watchers get invoked before the process blocks and check watchers |
1245 | afterwards. |
1857 | afterwards. |
1246 | .PP |
1858 | .PP |
|
|
1859 | You \fImust not\fR call \f(CW\*(C`ev_loop\*(C'\fR or similar functions that enter |
|
|
1860 | the current event loop from either \f(CW\*(C`ev_prepare\*(C'\fR or \f(CW\*(C`ev_check\*(C'\fR |
|
|
1861 | watchers. Other loops than the current one are fine, however. The |
|
|
1862 | rationale behind this is that you do not need to check for recursion in |
|
|
1863 | those watchers, i.e. the sequence will always be \f(CW\*(C`ev_prepare\*(C'\fR, blocking, |
|
|
1864 | \&\f(CW\*(C`ev_check\*(C'\fR so if you have one watcher of each kind they will always be |
|
|
1865 | called in pairs bracketing the blocking call. |
|
|
1866 | .PP |
1247 | Their main purpose is to integrate other event mechanisms into libev and |
1867 | Their main purpose is to integrate other event mechanisms into libev and |
1248 | their use is somewhat advanced. This could be used, for example, to track |
1868 | their use is somewhat advanced. This could be used, for example, to track |
1249 | variable changes, implement your own watchers, integrate net-snmp or a |
1869 | variable changes, implement your own watchers, integrate net-snmp or a |
1250 | coroutine library and lots more. |
1870 | coroutine library and lots more. They are also occasionally useful if |
|
|
1871 | you cache some data and want to flush it before blocking (for example, |
|
|
1872 | in X programs you might want to do an \f(CW\*(C`XFlush ()\*(C'\fR in an \f(CW\*(C`ev_prepare\*(C'\fR |
|
|
1873 | watcher). |
1251 | .PP |
1874 | .PP |
1252 | This is done by examining in each prepare call which file descriptors need |
1875 | This is done by examining in each prepare call which file descriptors need |
1253 | to be watched by the other library, registering \f(CW\*(C`ev_io\*(C'\fR watchers for |
1876 | to be watched by the other library, registering \f(CW\*(C`ev_io\*(C'\fR watchers for |
1254 | them and starting an \f(CW\*(C`ev_timer\*(C'\fR watcher for any timeouts (many libraries |
1877 | them and starting an \f(CW\*(C`ev_timer\*(C'\fR watcher for any timeouts (many libraries |
1255 | provide just this functionality). Then, in the check watcher you check for |
1878 | provide just this functionality). Then, in the check watcher you check for |
… | |
… | |
1264 | are ready to run (it's actually more complicated: it only runs coroutines |
1887 | are ready to run (it's actually more complicated: it only runs coroutines |
1265 | with priority higher than or equal to the event loop and one coroutine |
1888 | with priority higher than or equal to the event loop and one coroutine |
1266 | of lower priority, but only once, using idle watchers to keep the event |
1889 | of lower priority, but only once, using idle watchers to keep the event |
1267 | loop from blocking if lower-priority coroutines are active, thus mapping |
1890 | loop from blocking if lower-priority coroutines are active, thus mapping |
1268 | low-priority coroutines to idle/background tasks). |
1891 | low-priority coroutines to idle/background tasks). |
|
|
1892 | .PP |
|
|
1893 | It is recommended to give \f(CW\*(C`ev_check\*(C'\fR watchers highest (\f(CW\*(C`EV_MAXPRI\*(C'\fR) |
|
|
1894 | priority, to ensure that they are being run before any other watchers |
|
|
1895 | after the poll. Also, \f(CW\*(C`ev_check\*(C'\fR watchers (and \f(CW\*(C`ev_prepare\*(C'\fR watchers, |
|
|
1896 | too) should not activate (\*(L"feed\*(R") events into libev. While libev fully |
|
|
1897 | supports this, they will be called before other \f(CW\*(C`ev_check\*(C'\fR watchers |
|
|
1898 | did their job. As \f(CW\*(C`ev_check\*(C'\fR watchers are often used to embed other |
|
|
1899 | (non\-libev) event loops those other event loops might be in an unusable |
|
|
1900 | state until their \f(CW\*(C`ev_check\*(C'\fR watcher ran (always remind yourself to |
|
|
1901 | coexist peacefully with others). |
|
|
1902 | .PP |
|
|
1903 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1904 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1269 | .IP "ev_prepare_init (ev_prepare *, callback)" 4 |
1905 | .IP "ev_prepare_init (ev_prepare *, callback)" 4 |
1270 | .IX Item "ev_prepare_init (ev_prepare *, callback)" |
1906 | .IX Item "ev_prepare_init (ev_prepare *, callback)" |
1271 | .PD 0 |
1907 | .PD 0 |
1272 | .IP "ev_check_init (ev_check *, callback)" 4 |
1908 | .IP "ev_check_init (ev_check *, callback)" 4 |
1273 | .IX Item "ev_check_init (ev_check *, callback)" |
1909 | .IX Item "ev_check_init (ev_check *, callback)" |
1274 | .PD |
1910 | .PD |
1275 | Initialises and configures the prepare or check watcher \- they have no |
1911 | Initialises and configures the prepare or check watcher \- they have no |
1276 | parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR |
1912 | parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR |
1277 | macros, but using them is utterly, utterly and completely pointless. |
1913 | macros, but using them is utterly, utterly and completely pointless. |
1278 | .PP |
1914 | .PP |
1279 | Example: *TODO*. |
1915 | There are a number of principal ways to embed other event loops or modules |
|
|
1916 | into libev. Here are some ideas on how to include libadns into libev |
|
|
1917 | (there is a Perl module named \f(CW\*(C`EV::ADNS\*(C'\fR that does this, which you could |
|
|
1918 | use for an actually working example. Another Perl module named \f(CW\*(C`EV::Glib\*(C'\fR |
|
|
1919 | embeds a Glib main context into libev, and finally, \f(CW\*(C`Glib::EV\*(C'\fR embeds \s-1EV\s0 |
|
|
1920 | into the Glib event loop). |
|
|
1921 | .PP |
|
|
1922 | Method 1: Add \s-1IO\s0 watchers and a timeout watcher in a prepare handler, |
|
|
1923 | and in a check watcher, destroy them and call into libadns. What follows |
|
|
1924 | is pseudo-code only of course. This requires you to either use a low |
|
|
1925 | priority for the check watcher or use \f(CW\*(C`ev_clear_pending\*(C'\fR explicitly, as |
|
|
1926 | the callbacks for the IO/timeout watchers might not have been called yet. |
|
|
1927 | .PP |
|
|
1928 | .Vb 2 |
|
|
1929 | \& static ev_io iow [nfd]; |
|
|
1930 | \& static ev_timer tw; |
|
|
1931 | .Ve |
|
|
1932 | .PP |
|
|
1933 | .Vb 4 |
|
|
1934 | \& static void |
|
|
1935 | \& io_cb (ev_loop *loop, ev_io *w, int revents) |
|
|
1936 | \& { |
|
|
1937 | \& } |
|
|
1938 | .Ve |
|
|
1939 | .PP |
|
|
1940 | .Vb 8 |
|
|
1941 | \& // create io watchers for each fd and a timer before blocking |
|
|
1942 | \& static void |
|
|
1943 | \& adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
|
|
1944 | \& { |
|
|
1945 | \& int timeout = 3600000; |
|
|
1946 | \& struct pollfd fds [nfd]; |
|
|
1947 | \& // actual code will need to loop here and realloc etc. |
|
|
1948 | \& adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
|
|
1949 | .Ve |
|
|
1950 | .PP |
|
|
1951 | .Vb 3 |
|
|
1952 | \& /* the callback is illegal, but won't be called as we stop during check */ |
|
|
1953 | \& ev_timer_init (&tw, 0, timeout * 1e-3); |
|
|
1954 | \& ev_timer_start (loop, &tw); |
|
|
1955 | .Ve |
|
|
1956 | .PP |
|
|
1957 | .Vb 6 |
|
|
1958 | \& // create one ev_io per pollfd |
|
|
1959 | \& for (int i = 0; i < nfd; ++i) |
|
|
1960 | \& { |
|
|
1961 | \& ev_io_init (iow + i, io_cb, fds [i].fd, |
|
|
1962 | \& ((fds [i].events & POLLIN ? EV_READ : 0) |
|
|
1963 | \& | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
|
|
1964 | .Ve |
|
|
1965 | .PP |
|
|
1966 | .Vb 4 |
|
|
1967 | \& fds [i].revents = 0; |
|
|
1968 | \& ev_io_start (loop, iow + i); |
|
|
1969 | \& } |
|
|
1970 | \& } |
|
|
1971 | .Ve |
|
|
1972 | .PP |
|
|
1973 | .Vb 5 |
|
|
1974 | \& // stop all watchers after blocking |
|
|
1975 | \& static void |
|
|
1976 | \& adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
|
|
1977 | \& { |
|
|
1978 | \& ev_timer_stop (loop, &tw); |
|
|
1979 | .Ve |
|
|
1980 | .PP |
|
|
1981 | .Vb 8 |
|
|
1982 | \& for (int i = 0; i < nfd; ++i) |
|
|
1983 | \& { |
|
|
1984 | \& // set the relevant poll flags |
|
|
1985 | \& // could also call adns_processreadable etc. here |
|
|
1986 | \& struct pollfd *fd = fds + i; |
|
|
1987 | \& int revents = ev_clear_pending (iow + i); |
|
|
1988 | \& if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
|
|
1989 | \& if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
|
|
1990 | .Ve |
|
|
1991 | .PP |
|
|
1992 | .Vb 3 |
|
|
1993 | \& // now stop the watcher |
|
|
1994 | \& ev_io_stop (loop, iow + i); |
|
|
1995 | \& } |
|
|
1996 | .Ve |
|
|
1997 | .PP |
|
|
1998 | .Vb 2 |
|
|
1999 | \& adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
|
|
2000 | \& } |
|
|
2001 | .Ve |
|
|
2002 | .PP |
|
|
2003 | Method 2: This would be just like method 1, but you run \f(CW\*(C`adns_afterpoll\*(C'\fR |
|
|
2004 | in the prepare watcher and would dispose of the check watcher. |
|
|
2005 | .PP |
|
|
2006 | Method 3: If the module to be embedded supports explicit event |
|
|
2007 | notification (adns does), you can also make use of the actual watcher |
|
|
2008 | callbacks, and only destroy/create the watchers in the prepare watcher. |
|
|
2009 | .PP |
|
|
2010 | .Vb 5 |
|
|
2011 | \& static void |
|
|
2012 | \& timer_cb (EV_P_ ev_timer *w, int revents) |
|
|
2013 | \& { |
|
|
2014 | \& adns_state ads = (adns_state)w->data; |
|
|
2015 | \& update_now (EV_A); |
|
|
2016 | .Ve |
|
|
2017 | .PP |
|
|
2018 | .Vb 2 |
|
|
2019 | \& adns_processtimeouts (ads, &tv_now); |
|
|
2020 | \& } |
|
|
2021 | .Ve |
|
|
2022 | .PP |
|
|
2023 | .Vb 5 |
|
|
2024 | \& static void |
|
|
2025 | \& io_cb (EV_P_ ev_io *w, int revents) |
|
|
2026 | \& { |
|
|
2027 | \& adns_state ads = (adns_state)w->data; |
|
|
2028 | \& update_now (EV_A); |
|
|
2029 | .Ve |
|
|
2030 | .PP |
|
|
2031 | .Vb 3 |
|
|
2032 | \& if (revents & EV_READ ) adns_processreadable (ads, w->fd, &tv_now); |
|
|
2033 | \& if (revents & EV_WRITE) adns_processwriteable (ads, w->fd, &tv_now); |
|
|
2034 | \& } |
|
|
2035 | .Ve |
|
|
2036 | .PP |
|
|
2037 | .Vb 1 |
|
|
2038 | \& // do not ever call adns_afterpoll |
|
|
2039 | .Ve |
|
|
2040 | .PP |
|
|
2041 | Method 4: Do not use a prepare or check watcher because the module you |
|
|
2042 | want to embed is too inflexible to support it. Instead, youc na override |
|
|
2043 | their poll function. The drawback with this solution is that the main |
|
|
2044 | loop is now no longer controllable by \s-1EV\s0. The \f(CW\*(C`Glib::EV\*(C'\fR module does |
|
|
2045 | this. |
|
|
2046 | .PP |
|
|
2047 | .Vb 4 |
|
|
2048 | \& static gint |
|
|
2049 | \& event_poll_func (GPollFD *fds, guint nfds, gint timeout) |
|
|
2050 | \& { |
|
|
2051 | \& int got_events = 0; |
|
|
2052 | .Ve |
|
|
2053 | .PP |
|
|
2054 | .Vb 2 |
|
|
2055 | \& for (n = 0; n < nfds; ++n) |
|
|
2056 | \& // create/start io watcher that sets the relevant bits in fds[n] and increment got_events |
|
|
2057 | .Ve |
|
|
2058 | .PP |
|
|
2059 | .Vb 2 |
|
|
2060 | \& if (timeout >= 0) |
|
|
2061 | \& // create/start timer |
|
|
2062 | .Ve |
|
|
2063 | .PP |
|
|
2064 | .Vb 2 |
|
|
2065 | \& // poll |
|
|
2066 | \& ev_loop (EV_A_ 0); |
|
|
2067 | .Ve |
|
|
2068 | .PP |
|
|
2069 | .Vb 3 |
|
|
2070 | \& // stop timer again |
|
|
2071 | \& if (timeout >= 0) |
|
|
2072 | \& ev_timer_stop (EV_A_ &to); |
|
|
2073 | .Ve |
|
|
2074 | .PP |
|
|
2075 | .Vb 3 |
|
|
2076 | \& // stop io watchers again - their callbacks should have set |
|
|
2077 | \& for (n = 0; n < nfds; ++n) |
|
|
2078 | \& ev_io_stop (EV_A_ iow [n]); |
|
|
2079 | .Ve |
|
|
2080 | .PP |
|
|
2081 | .Vb 2 |
|
|
2082 | \& return got_events; |
|
|
2083 | \& } |
|
|
2084 | .Ve |
1280 | .ie n .Sh """ev_embed"" \- when one backend isn't enough..." |
2085 | .ie n .Sh """ev_embed"" \- when one backend isn't enough..." |
1281 | .el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..." |
2086 | .el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..." |
1282 | .IX Subsection "ev_embed - when one backend isn't enough..." |
2087 | .IX Subsection "ev_embed - when one backend isn't enough..." |
1283 | This is a rather advanced watcher type that lets you embed one event loop |
2088 | This is a rather advanced watcher type that lets you embed one event loop |
1284 | into another (currently only \f(CW\*(C`ev_io\*(C'\fR events are supported in the embedded |
2089 | into another (currently only \f(CW\*(C`ev_io\*(C'\fR events are supported in the embedded |
… | |
… | |
1351 | \& ev_embed_start (loop_hi, &embed); |
2156 | \& ev_embed_start (loop_hi, &embed); |
1352 | \& } |
2157 | \& } |
1353 | \& else |
2158 | \& else |
1354 | \& loop_lo = loop_hi; |
2159 | \& loop_lo = loop_hi; |
1355 | .Ve |
2160 | .Ve |
|
|
2161 | .PP |
|
|
2162 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
2163 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1356 | .IP "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
2164 | .IP "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
1357 | .IX Item "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" |
2165 | .IX Item "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" |
1358 | .PD 0 |
2166 | .PD 0 |
1359 | .IP "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
2167 | .IP "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
1360 | .IX Item "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" |
2168 | .IX Item "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" |
… | |
… | |
1367 | .IP "ev_embed_sweep (loop, ev_embed *)" 4 |
2175 | .IP "ev_embed_sweep (loop, ev_embed *)" 4 |
1368 | .IX Item "ev_embed_sweep (loop, ev_embed *)" |
2176 | .IX Item "ev_embed_sweep (loop, ev_embed *)" |
1369 | Make a single, non-blocking sweep over the embedded loop. This works |
2177 | Make a single, non-blocking sweep over the embedded loop. This works |
1370 | similarly to \f(CW\*(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\*(C'\fR, but in the most |
2178 | similarly to \f(CW\*(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\*(C'\fR, but in the most |
1371 | apropriate way for embedded loops. |
2179 | apropriate way for embedded loops. |
|
|
2180 | .IP "struct ev_loop *other [read\-only]" 4 |
|
|
2181 | .IX Item "struct ev_loop *other [read-only]" |
|
|
2182 | The embedded event loop. |
|
|
2183 | .ie n .Sh """ev_fork"" \- the audacity to resume the event loop after a fork" |
|
|
2184 | .el .Sh "\f(CWev_fork\fP \- the audacity to resume the event loop after a fork" |
|
|
2185 | .IX Subsection "ev_fork - the audacity to resume the event loop after a fork" |
|
|
2186 | Fork watchers are called when a \f(CW\*(C`fork ()\*(C'\fR was detected (usually because |
|
|
2187 | whoever is a good citizen cared to tell libev about it by calling |
|
|
2188 | \&\f(CW\*(C`ev_default_fork\*(C'\fR or \f(CW\*(C`ev_loop_fork\*(C'\fR). The invocation is done before the |
|
|
2189 | event loop blocks next and before \f(CW\*(C`ev_check\*(C'\fR watchers are being called, |
|
|
2190 | and only in the child after the fork. If whoever good citizen calling |
|
|
2191 | \&\f(CW\*(C`ev_default_fork\*(C'\fR cheats and calls it in the wrong process, the fork |
|
|
2192 | handlers will be invoked, too, of course. |
|
|
2193 | .PP |
|
|
2194 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
2195 | .IX Subsection "Watcher-Specific Functions and Data Members" |
|
|
2196 | .IP "ev_fork_init (ev_signal *, callback)" 4 |
|
|
2197 | .IX Item "ev_fork_init (ev_signal *, callback)" |
|
|
2198 | Initialises and configures the fork watcher \- it has no parameters of any |
|
|
2199 | kind. There is a \f(CW\*(C`ev_fork_set\*(C'\fR macro, but using it is utterly pointless, |
|
|
2200 | believe me. |
1372 | .SH "OTHER FUNCTIONS" |
2201 | .SH "OTHER FUNCTIONS" |
1373 | .IX Header "OTHER FUNCTIONS" |
2202 | .IX Header "OTHER FUNCTIONS" |
1374 | There are some other functions of possible interest. Described. Here. Now. |
2203 | There are some other functions of possible interest. Described. Here. Now. |
1375 | .IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4 |
2204 | .IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4 |
1376 | .IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" |
2205 | .IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" |
… | |
… | |
1448 | .PP |
2277 | .PP |
1449 | .Vb 1 |
2278 | .Vb 1 |
1450 | \& #include <ev++.h> |
2279 | \& #include <ev++.h> |
1451 | .Ve |
2280 | .Ve |
1452 | .PP |
2281 | .PP |
1453 | (it is not installed by default). This automatically includes \fIev.h\fR |
2282 | This automatically includes \fIev.h\fR and puts all of its definitions (many |
1454 | and puts all of its definitions (many of them macros) into the global |
2283 | of them macros) into the global namespace. All \*(C+ specific things are |
1455 | namespace. All \*(C+ specific things are put into the \f(CW\*(C`ev\*(C'\fR namespace. |
2284 | put into the \f(CW\*(C`ev\*(C'\fR namespace. It should support all the same embedding |
|
|
2285 | options as \fIev.h\fR, most notably \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. |
1456 | .PP |
2286 | .PP |
1457 | It should support all the same embedding options as \fIev.h\fR, most notably |
2287 | Care has been taken to keep the overhead low. The only data member the \*(C+ |
1458 | \&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. |
2288 | classes add (compared to plain C\-style watchers) is the event loop pointer |
|
|
2289 | that the watcher is associated with (or no additional members at all if |
|
|
2290 | you disable \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR when embedding libev). |
|
|
2291 | .PP |
|
|
2292 | Currently, functions, and static and non-static member functions can be |
|
|
2293 | used as callbacks. Other types should be easy to add as long as they only |
|
|
2294 | need one additional pointer for context. If you need support for other |
|
|
2295 | types of functors please contact the author (preferably after implementing |
|
|
2296 | it). |
1459 | .PP |
2297 | .PP |
1460 | Here is a list of things available in the \f(CW\*(C`ev\*(C'\fR namespace: |
2298 | Here is a list of things available in the \f(CW\*(C`ev\*(C'\fR namespace: |
1461 | .ie n .IP """ev::READ""\fR, \f(CW""ev::WRITE"" etc." 4 |
2299 | .ie n .IP """ev::READ""\fR, \f(CW""ev::WRITE"" etc." 4 |
1462 | .el .IP "\f(CWev::READ\fR, \f(CWev::WRITE\fR etc." 4 |
2300 | .el .IP "\f(CWev::READ\fR, \f(CWev::WRITE\fR etc." 4 |
1463 | .IX Item "ev::READ, ev::WRITE etc." |
2301 | .IX Item "ev::READ, ev::WRITE etc." |
… | |
… | |
1475 | which is called \f(CW\*(C`ev::sig\*(C'\fR to avoid clashes with the \f(CW\*(C`signal\*(C'\fR macro |
2313 | which is called \f(CW\*(C`ev::sig\*(C'\fR to avoid clashes with the \f(CW\*(C`signal\*(C'\fR macro |
1476 | defines by many implementations. |
2314 | defines by many implementations. |
1477 | .Sp |
2315 | .Sp |
1478 | All of those classes have these methods: |
2316 | All of those classes have these methods: |
1479 | .RS 4 |
2317 | .RS 4 |
1480 | .IP "ev::TYPE::TYPE (object *, object::method *)" 4 |
2318 | .IP "ev::TYPE::TYPE ()" 4 |
1481 | .IX Item "ev::TYPE::TYPE (object *, object::method *)" |
2319 | .IX Item "ev::TYPE::TYPE ()" |
1482 | .PD 0 |
2320 | .PD 0 |
1483 | .IP "ev::TYPE::TYPE (object *, object::method *, struct ev_loop *)" 4 |
2321 | .IP "ev::TYPE::TYPE (struct ev_loop *)" 4 |
1484 | .IX Item "ev::TYPE::TYPE (object *, object::method *, struct ev_loop *)" |
2322 | .IX Item "ev::TYPE::TYPE (struct ev_loop *)" |
1485 | .IP "ev::TYPE::~TYPE" 4 |
2323 | .IP "ev::TYPE::~TYPE" 4 |
1486 | .IX Item "ev::TYPE::~TYPE" |
2324 | .IX Item "ev::TYPE::~TYPE" |
1487 | .PD |
2325 | .PD |
1488 | The constructor takes a pointer to an object and a method pointer to |
2326 | The constructor (optionally) takes an event loop to associate the watcher |
1489 | the event handler callback to call in this class. The constructor calls |
2327 | with. If it is omitted, it will use \f(CW\*(C`EV_DEFAULT\*(C'\fR. |
1490 | \&\f(CW\*(C`ev_init\*(C'\fR for you, which means you have to call the \f(CW\*(C`set\*(C'\fR method |
2328 | .Sp |
1491 | before starting it. If you do not specify a loop then the constructor |
2329 | The constructor calls \f(CW\*(C`ev_init\*(C'\fR for you, which means you have to call the |
1492 | automatically associates the default loop with this watcher. |
2330 | \&\f(CW\*(C`set\*(C'\fR method before starting it. |
|
|
2331 | .Sp |
|
|
2332 | It will not set a callback, however: You have to call the templated \f(CW\*(C`set\*(C'\fR |
|
|
2333 | method to set a callback before you can start the watcher. |
|
|
2334 | .Sp |
|
|
2335 | (The reason why you have to use a method is a limitation in \*(C+ which does |
|
|
2336 | not allow explicit template arguments for constructors). |
1493 | .Sp |
2337 | .Sp |
1494 | The destructor automatically stops the watcher if it is active. |
2338 | The destructor automatically stops the watcher if it is active. |
|
|
2339 | .IP "w\->set<class, &class::method> (object *)" 4 |
|
|
2340 | .IX Item "w->set<class, &class::method> (object *)" |
|
|
2341 | This method sets the callback method to call. The method has to have a |
|
|
2342 | signature of \f(CW\*(C`void (*)(ev_TYPE &, int)\*(C'\fR, it receives the watcher as |
|
|
2343 | first argument and the \f(CW\*(C`revents\*(C'\fR as second. The object must be given as |
|
|
2344 | parameter and is stored in the \f(CW\*(C`data\*(C'\fR member of the watcher. |
|
|
2345 | .Sp |
|
|
2346 | This method synthesizes efficient thunking code to call your method from |
|
|
2347 | the C callback that libev requires. If your compiler can inline your |
|
|
2348 | callback (i.e. it is visible to it at the place of the \f(CW\*(C`set\*(C'\fR call and |
|
|
2349 | your compiler is good :), then the method will be fully inlined into the |
|
|
2350 | thunking function, making it as fast as a direct C callback. |
|
|
2351 | .Sp |
|
|
2352 | Example: simple class declaration and watcher initialisation |
|
|
2353 | .Sp |
|
|
2354 | .Vb 4 |
|
|
2355 | \& struct myclass |
|
|
2356 | \& { |
|
|
2357 | \& void io_cb (ev::io &w, int revents) { } |
|
|
2358 | \& } |
|
|
2359 | .Ve |
|
|
2360 | .Sp |
|
|
2361 | .Vb 3 |
|
|
2362 | \& myclass obj; |
|
|
2363 | \& ev::io iow; |
|
|
2364 | \& iow.set <myclass, &myclass::io_cb> (&obj); |
|
|
2365 | .Ve |
|
|
2366 | .IP "w\->set<function> (void *data = 0)" 4 |
|
|
2367 | .IX Item "w->set<function> (void *data = 0)" |
|
|
2368 | Also sets a callback, but uses a static method or plain function as |
|
|
2369 | callback. The optional \f(CW\*(C`data\*(C'\fR argument will be stored in the watcher's |
|
|
2370 | \&\f(CW\*(C`data\*(C'\fR member and is free for you to use. |
|
|
2371 | .Sp |
|
|
2372 | The prototype of the \f(CW\*(C`function\*(C'\fR must be \f(CW\*(C`void (*)(ev::TYPE &w, int)\*(C'\fR. |
|
|
2373 | .Sp |
|
|
2374 | See the method\-\f(CW\*(C`set\*(C'\fR above for more details. |
|
|
2375 | .Sp |
|
|
2376 | Example: |
|
|
2377 | .Sp |
|
|
2378 | .Vb 2 |
|
|
2379 | \& static void io_cb (ev::io &w, int revents) { } |
|
|
2380 | \& iow.set <io_cb> (); |
|
|
2381 | .Ve |
1495 | .IP "w\->set (struct ev_loop *)" 4 |
2382 | .IP "w\->set (struct ev_loop *)" 4 |
1496 | .IX Item "w->set (struct ev_loop *)" |
2383 | .IX Item "w->set (struct ev_loop *)" |
1497 | Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only |
2384 | Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only |
1498 | do this when the watcher is inactive (and not pending either). |
2385 | do this when the watcher is inactive (and not pending either). |
1499 | .IP "w\->set ([args])" 4 |
2386 | .IP "w\->set ([args])" 4 |
1500 | .IX Item "w->set ([args])" |
2387 | .IX Item "w->set ([args])" |
1501 | Basically the same as \f(CW\*(C`ev_TYPE_set\*(C'\fR, with the same args. Must be |
2388 | Basically the same as \f(CW\*(C`ev_TYPE_set\*(C'\fR, with the same args. Must be |
1502 | called at least once. Unlike the C counterpart, an active watcher gets |
2389 | called at least once. Unlike the C counterpart, an active watcher gets |
1503 | automatically stopped and restarted. |
2390 | automatically stopped and restarted when reconfiguring it with this |
|
|
2391 | method. |
1504 | .IP "w\->start ()" 4 |
2392 | .IP "w\->start ()" 4 |
1505 | .IX Item "w->start ()" |
2393 | .IX Item "w->start ()" |
1506 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument as the |
2394 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument, as the |
1507 | constructor already takes the loop. |
2395 | constructor already stores the event loop. |
1508 | .IP "w\->stop ()" 4 |
2396 | .IP "w\->stop ()" 4 |
1509 | .IX Item "w->stop ()" |
2397 | .IX Item "w->stop ()" |
1510 | Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument. |
2398 | Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument. |
1511 | .ie n .IP "w\->again () ""ev::timer""\fR, \f(CW""ev::periodic"" only" 4 |
2399 | .ie n .IP "w\->again () (""ev::timer""\fR, \f(CW""ev::periodic"" only)" 4 |
1512 | .el .IP "w\->again () \f(CWev::timer\fR, \f(CWev::periodic\fR only" 4 |
2400 | .el .IP "w\->again () (\f(CWev::timer\fR, \f(CWev::periodic\fR only)" 4 |
1513 | .IX Item "w->again () ev::timer, ev::periodic only" |
2401 | .IX Item "w->again () (ev::timer, ev::periodic only)" |
1514 | For \f(CW\*(C`ev::timer\*(C'\fR and \f(CW\*(C`ev::periodic\*(C'\fR, this invokes the corresponding |
2402 | For \f(CW\*(C`ev::timer\*(C'\fR and \f(CW\*(C`ev::periodic\*(C'\fR, this invokes the corresponding |
1515 | \&\f(CW\*(C`ev_TYPE_again\*(C'\fR function. |
2403 | \&\f(CW\*(C`ev_TYPE_again\*(C'\fR function. |
1516 | .ie n .IP "w\->sweep () ""ev::embed"" only" 4 |
2404 | .ie n .IP "w\->sweep () (""ev::embed"" only)" 4 |
1517 | .el .IP "w\->sweep () \f(CWev::embed\fR only" 4 |
2405 | .el .IP "w\->sweep () (\f(CWev::embed\fR only)" 4 |
1518 | .IX Item "w->sweep () ev::embed only" |
2406 | .IX Item "w->sweep () (ev::embed only)" |
1519 | Invokes \f(CW\*(C`ev_embed_sweep\*(C'\fR. |
2407 | Invokes \f(CW\*(C`ev_embed_sweep\*(C'\fR. |
|
|
2408 | .ie n .IP "w\->update () (""ev::stat"" only)" 4 |
|
|
2409 | .el .IP "w\->update () (\f(CWev::stat\fR only)" 4 |
|
|
2410 | .IX Item "w->update () (ev::stat only)" |
|
|
2411 | Invokes \f(CW\*(C`ev_stat_stat\*(C'\fR. |
1520 | .RE |
2412 | .RE |
1521 | .RS 4 |
2413 | .RS 4 |
1522 | .RE |
2414 | .RE |
1523 | .PP |
2415 | .PP |
1524 | Example: Define a class with an \s-1IO\s0 and idle watcher, start one of them in |
2416 | Example: Define a class with an \s-1IO\s0 and idle watcher, start one of them in |
… | |
… | |
1534 | .Vb 2 |
2426 | .Vb 2 |
1535 | \& myclass (); |
2427 | \& myclass (); |
1536 | \& } |
2428 | \& } |
1537 | .Ve |
2429 | .Ve |
1538 | .PP |
2430 | .PP |
1539 | .Vb 6 |
2431 | .Vb 4 |
1540 | \& myclass::myclass (int fd) |
2432 | \& myclass::myclass (int fd) |
1541 | \& : io (this, &myclass::io_cb), |
|
|
1542 | \& idle (this, &myclass::idle_cb) |
|
|
1543 | \& { |
2433 | \& { |
|
|
2434 | \& io .set <myclass, &myclass::io_cb > (this); |
|
|
2435 | \& idle.set <myclass, &myclass::idle_cb> (this); |
|
|
2436 | .Ve |
|
|
2437 | .PP |
|
|
2438 | .Vb 2 |
1544 | \& io.start (fd, ev::READ); |
2439 | \& io.start (fd, ev::READ); |
1545 | \& } |
2440 | \& } |
|
|
2441 | .Ve |
|
|
2442 | .SH "MACRO MAGIC" |
|
|
2443 | .IX Header "MACRO MAGIC" |
|
|
2444 | Libev can be compiled with a variety of options, the most fundamantal |
|
|
2445 | of which is \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines whether (most) |
|
|
2446 | functions and callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument. |
|
|
2447 | .PP |
|
|
2448 | To make it easier to write programs that cope with either variant, the |
|
|
2449 | following macros are defined: |
|
|
2450 | .ie n .IP """EV_A""\fR, \f(CW""EV_A_""" 4 |
|
|
2451 | .el .IP "\f(CWEV_A\fR, \f(CWEV_A_\fR" 4 |
|
|
2452 | .IX Item "EV_A, EV_A_" |
|
|
2453 | This provides the loop \fIargument\fR for functions, if one is required (\*(L"ev |
|
|
2454 | loop argument\*(R"). The \f(CW\*(C`EV_A\*(C'\fR form is used when this is the sole argument, |
|
|
2455 | \&\f(CW\*(C`EV_A_\*(C'\fR is used when other arguments are following. Example: |
|
|
2456 | .Sp |
|
|
2457 | .Vb 3 |
|
|
2458 | \& ev_unref (EV_A); |
|
|
2459 | \& ev_timer_add (EV_A_ watcher); |
|
|
2460 | \& ev_loop (EV_A_ 0); |
|
|
2461 | .Ve |
|
|
2462 | .Sp |
|
|
2463 | It assumes the variable \f(CW\*(C`loop\*(C'\fR of type \f(CW\*(C`struct ev_loop *\*(C'\fR is in scope, |
|
|
2464 | which is often provided by the following macro. |
|
|
2465 | .ie n .IP """EV_P""\fR, \f(CW""EV_P_""" 4 |
|
|
2466 | .el .IP "\f(CWEV_P\fR, \f(CWEV_P_\fR" 4 |
|
|
2467 | .IX Item "EV_P, EV_P_" |
|
|
2468 | This provides the loop \fIparameter\fR for functions, if one is required (\*(L"ev |
|
|
2469 | loop parameter\*(R"). The \f(CW\*(C`EV_P\*(C'\fR form is used when this is the sole parameter, |
|
|
2470 | \&\f(CW\*(C`EV_P_\*(C'\fR is used when other parameters are following. Example: |
|
|
2471 | .Sp |
|
|
2472 | .Vb 2 |
|
|
2473 | \& // this is how ev_unref is being declared |
|
|
2474 | \& static void ev_unref (EV_P); |
|
|
2475 | .Ve |
|
|
2476 | .Sp |
|
|
2477 | .Vb 2 |
|
|
2478 | \& // this is how you can declare your typical callback |
|
|
2479 | \& static void cb (EV_P_ ev_timer *w, int revents) |
|
|
2480 | .Ve |
|
|
2481 | .Sp |
|
|
2482 | It declares a parameter \f(CW\*(C`loop\*(C'\fR of type \f(CW\*(C`struct ev_loop *\*(C'\fR, quite |
|
|
2483 | suitable for use with \f(CW\*(C`EV_A\*(C'\fR. |
|
|
2484 | .ie n .IP """EV_DEFAULT""\fR, \f(CW""EV_DEFAULT_""" 4 |
|
|
2485 | .el .IP "\f(CWEV_DEFAULT\fR, \f(CWEV_DEFAULT_\fR" 4 |
|
|
2486 | .IX Item "EV_DEFAULT, EV_DEFAULT_" |
|
|
2487 | Similar to the other two macros, this gives you the value of the default |
|
|
2488 | loop, if multiple loops are supported (\*(L"ev loop default\*(R"). |
|
|
2489 | .PP |
|
|
2490 | Example: Declare and initialise a check watcher, utilising the above |
|
|
2491 | macros so it will work regardless of whether multiple loops are supported |
|
|
2492 | or not. |
|
|
2493 | .PP |
|
|
2494 | .Vb 5 |
|
|
2495 | \& static void |
|
|
2496 | \& check_cb (EV_P_ ev_timer *w, int revents) |
|
|
2497 | \& { |
|
|
2498 | \& ev_check_stop (EV_A_ w); |
|
|
2499 | \& } |
|
|
2500 | .Ve |
|
|
2501 | .PP |
|
|
2502 | .Vb 4 |
|
|
2503 | \& ev_check check; |
|
|
2504 | \& ev_check_init (&check, check_cb); |
|
|
2505 | \& ev_check_start (EV_DEFAULT_ &check); |
|
|
2506 | \& ev_loop (EV_DEFAULT_ 0); |
1546 | .Ve |
2507 | .Ve |
1547 | .SH "EMBEDDING" |
2508 | .SH "EMBEDDING" |
1548 | .IX Header "EMBEDDING" |
2509 | .IX Header "EMBEDDING" |
1549 | Libev can (and often is) directly embedded into host |
2510 | Libev can (and often is) directly embedded into host |
1550 | applications. Examples of applications that embed it include the Deliantra |
2511 | applications. Examples of applications that embed it include the Deliantra |
1551 | Game Server, the \s-1EV\s0 perl module, the \s-1GNU\s0 Virtual Private Ethernet (gvpe) |
2512 | Game Server, the \s-1EV\s0 perl module, the \s-1GNU\s0 Virtual Private Ethernet (gvpe) |
1552 | and rxvt\-unicode. |
2513 | and rxvt\-unicode. |
1553 | .PP |
2514 | .PP |
1554 | The goal is to enable you to just copy the neecssary files into your |
2515 | The goal is to enable you to just copy the necessary files into your |
1555 | source directory without having to change even a single line in them, so |
2516 | source directory without having to change even a single line in them, so |
1556 | you can easily upgrade by simply copying (or having a checked-out copy of |
2517 | you can easily upgrade by simply copying (or having a checked-out copy of |
1557 | libev somewhere in your source tree). |
2518 | libev somewhere in your source tree). |
1558 | .Sh "\s-1FILESETS\s0" |
2519 | .Sh "\s-1FILESETS\s0" |
1559 | .IX Subsection "FILESETS" |
2520 | .IX Subsection "FILESETS" |
… | |
… | |
1599 | .Vb 1 |
2560 | .Vb 1 |
1600 | \& ev_win32.c required on win32 platforms only |
2561 | \& ev_win32.c required on win32 platforms only |
1601 | .Ve |
2562 | .Ve |
1602 | .PP |
2563 | .PP |
1603 | .Vb 5 |
2564 | .Vb 5 |
1604 | \& ev_select.c only when select backend is enabled (which is is by default) |
2565 | \& ev_select.c only when select backend is enabled (which is enabled by default) |
1605 | \& ev_poll.c only when poll backend is enabled (disabled by default) |
2566 | \& ev_poll.c only when poll backend is enabled (disabled by default) |
1606 | \& ev_epoll.c only when the epoll backend is enabled (disabled by default) |
2567 | \& ev_epoll.c only when the epoll backend is enabled (disabled by default) |
1607 | \& ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
2568 | \& ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
1608 | \& ev_port.c only when the solaris port backend is enabled (disabled by default) |
2569 | \& ev_port.c only when the solaris port backend is enabled (disabled by default) |
1609 | .Ve |
2570 | .Ve |
1610 | .PP |
2571 | .PP |
1611 | \&\fIev.c\fR includes the backend files directly when enabled, so you only need |
2572 | \&\fIev.c\fR includes the backend files directly when enabled, so you only need |
1612 | to compile a single file. |
2573 | to compile this single file. |
1613 | .PP |
2574 | .PP |
1614 | \fI\s-1LIBEVENT\s0 \s-1COMPATIBILITY\s0 \s-1API\s0\fR |
2575 | \fI\s-1LIBEVENT\s0 \s-1COMPATIBILITY\s0 \s-1API\s0\fR |
1615 | .IX Subsection "LIBEVENT COMPATIBILITY API" |
2576 | .IX Subsection "LIBEVENT COMPATIBILITY API" |
1616 | .PP |
2577 | .PP |
1617 | To include the libevent compatibility \s-1API\s0, also include: |
2578 | To include the libevent compatibility \s-1API\s0, also include: |
… | |
… | |
1638 | \fI\s-1AUTOCONF\s0 \s-1SUPPORT\s0\fR |
2599 | \fI\s-1AUTOCONF\s0 \s-1SUPPORT\s0\fR |
1639 | .IX Subsection "AUTOCONF SUPPORT" |
2600 | .IX Subsection "AUTOCONF SUPPORT" |
1640 | .PP |
2601 | .PP |
1641 | Instead of using \f(CW\*(C`EV_STANDALONE=1\*(C'\fR and providing your config in |
2602 | Instead of using \f(CW\*(C`EV_STANDALONE=1\*(C'\fR and providing your config in |
1642 | whatever way you want, you can also \f(CW\*(C`m4_include([libev.m4])\*(C'\fR in your |
2603 | whatever way you want, you can also \f(CW\*(C`m4_include([libev.m4])\*(C'\fR in your |
1643 | \&\fIconfigure.ac\fR and leave \f(CW\*(C`EV_STANDALONE\*(C'\fR off. \fIev.c\fR will then include |
2604 | \&\fIconfigure.ac\fR and leave \f(CW\*(C`EV_STANDALONE\*(C'\fR undefined. \fIev.c\fR will then |
1644 | \&\fIconfig.h\fR and configure itself accordingly. |
2605 | include \fIconfig.h\fR and configure itself accordingly. |
1645 | .PP |
2606 | .PP |
1646 | For this of course you need the m4 file: |
2607 | For this of course you need the m4 file: |
1647 | .PP |
2608 | .PP |
1648 | .Vb 1 |
2609 | .Vb 1 |
1649 | \& libev.m4 |
2610 | \& libev.m4 |
… | |
… | |
1664 | .IX Item "EV_USE_MONOTONIC" |
2625 | .IX Item "EV_USE_MONOTONIC" |
1665 | If defined to be \f(CW1\fR, libev will try to detect the availability of the |
2626 | If defined to be \f(CW1\fR, libev will try to detect the availability of the |
1666 | monotonic clock option at both compiletime and runtime. Otherwise no use |
2627 | monotonic clock option at both compiletime and runtime. Otherwise no use |
1667 | of the monotonic clock option will be attempted. If you enable this, you |
2628 | of the monotonic clock option will be attempted. If you enable this, you |
1668 | usually have to link against librt or something similar. Enabling it when |
2629 | usually have to link against librt or something similar. Enabling it when |
1669 | the functionality isn't available is safe, though, althoguh you have |
2630 | the functionality isn't available is safe, though, although you have |
1670 | to make sure you link against any libraries where the \f(CW\*(C`clock_gettime\*(C'\fR |
2631 | to make sure you link against any libraries where the \f(CW\*(C`clock_gettime\*(C'\fR |
1671 | function is hiding in (often \fI\-lrt\fR). |
2632 | function is hiding in (often \fI\-lrt\fR). |
1672 | .IP "\s-1EV_USE_REALTIME\s0" 4 |
2633 | .IP "\s-1EV_USE_REALTIME\s0" 4 |
1673 | .IX Item "EV_USE_REALTIME" |
2634 | .IX Item "EV_USE_REALTIME" |
1674 | If defined to be \f(CW1\fR, libev will try to detect the availability of the |
2635 | If defined to be \f(CW1\fR, libev will try to detect the availability of the |
1675 | realtime clock option at compiletime (and assume its availability at |
2636 | realtime clock option at compiletime (and assume its availability at |
1676 | runtime if successful). Otherwise no use of the realtime clock option will |
2637 | runtime if successful). Otherwise no use of the realtime clock option will |
1677 | be attempted. This effectively replaces \f(CW\*(C`gettimeofday\*(C'\fR by \f(CW\*(C`clock_get |
2638 | be attempted. This effectively replaces \f(CW\*(C`gettimeofday\*(C'\fR by \f(CW\*(C`clock_get |
1678 | (CLOCK_REALTIME, ...)\*(C'\fR and will not normally affect correctness. See tzhe note about libraries |
2639 | (CLOCK_REALTIME, ...)\*(C'\fR and will not normally affect correctness. See the |
1679 | in the description of \f(CW\*(C`EV_USE_MONOTONIC\*(C'\fR, though. |
2640 | note about libraries in the description of \f(CW\*(C`EV_USE_MONOTONIC\*(C'\fR, though. |
|
|
2641 | .IP "\s-1EV_USE_NANOSLEEP\s0" 4 |
|
|
2642 | .IX Item "EV_USE_NANOSLEEP" |
|
|
2643 | If defined to be \f(CW1\fR, libev will assume that \f(CW\*(C`nanosleep ()\*(C'\fR is available |
|
|
2644 | and will use it for delays. Otherwise it will use \f(CW\*(C`select ()\*(C'\fR. |
1680 | .IP "\s-1EV_USE_SELECT\s0" 4 |
2645 | .IP "\s-1EV_USE_SELECT\s0" 4 |
1681 | .IX Item "EV_USE_SELECT" |
2646 | .IX Item "EV_USE_SELECT" |
1682 | If undefined or defined to be \f(CW1\fR, libev will compile in support for the |
2647 | If undefined or defined to be \f(CW1\fR, libev will compile in support for the |
1683 | \&\f(CW\*(C`select\*(C'\fR(2) backend. No attempt at autodetection will be done: if no |
2648 | \&\f(CW\*(C`select\*(C'\fR(2) backend. No attempt at autodetection will be done: if no |
1684 | other method takes over, select will be it. Otherwise the select backend |
2649 | other method takes over, select will be it. Otherwise the select backend |
… | |
… | |
1730 | otherwise another method will be used as fallback. This is the preferred |
2695 | otherwise another method will be used as fallback. This is the preferred |
1731 | backend for Solaris 10 systems. |
2696 | backend for Solaris 10 systems. |
1732 | .IP "\s-1EV_USE_DEVPOLL\s0" 4 |
2697 | .IP "\s-1EV_USE_DEVPOLL\s0" 4 |
1733 | .IX Item "EV_USE_DEVPOLL" |
2698 | .IX Item "EV_USE_DEVPOLL" |
1734 | reserved for future expansion, works like the \s-1USE\s0 symbols above. |
2699 | reserved for future expansion, works like the \s-1USE\s0 symbols above. |
|
|
2700 | .IP "\s-1EV_USE_INOTIFY\s0" 4 |
|
|
2701 | .IX Item "EV_USE_INOTIFY" |
|
|
2702 | If defined to be \f(CW1\fR, libev will compile in support for the Linux inotify |
|
|
2703 | interface to speed up \f(CW\*(C`ev_stat\*(C'\fR watchers. Its actual availability will |
|
|
2704 | be detected at runtime. |
1735 | .IP "\s-1EV_H\s0" 4 |
2705 | .IP "\s-1EV_H\s0" 4 |
1736 | .IX Item "EV_H" |
2706 | .IX Item "EV_H" |
1737 | The name of the \fIev.h\fR header file used to include it. The default if |
2707 | The name of the \fIev.h\fR header file used to include it. The default if |
1738 | undefined is \f(CW\*(C`<ev.h>\*(C'\fR in \fIevent.h\fR and \f(CW"ev.h"\fR in \fIev.c\fR. This |
2708 | undefined is \f(CW"ev.h"\fR in \fIevent.h\fR and \fIev.c\fR. This can be used to |
1739 | can be used to virtually rename the \fIev.h\fR header file in case of conflicts. |
2709 | virtually rename the \fIev.h\fR header file in case of conflicts. |
1740 | .IP "\s-1EV_CONFIG_H\s0" 4 |
2710 | .IP "\s-1EV_CONFIG_H\s0" 4 |
1741 | .IX Item "EV_CONFIG_H" |
2711 | .IX Item "EV_CONFIG_H" |
1742 | If \f(CW\*(C`EV_STANDALONE\*(C'\fR isn't \f(CW1\fR, this variable can be used to override |
2712 | If \f(CW\*(C`EV_STANDALONE\*(C'\fR isn't \f(CW1\fR, this variable can be used to override |
1743 | \&\fIev.c\fR's idea of where to find the \fIconfig.h\fR file, similarly to |
2713 | \&\fIev.c\fR's idea of where to find the \fIconfig.h\fR file, similarly to |
1744 | \&\f(CW\*(C`EV_H\*(C'\fR, above. |
2714 | \&\f(CW\*(C`EV_H\*(C'\fR, above. |
1745 | .IP "\s-1EV_EVENT_H\s0" 4 |
2715 | .IP "\s-1EV_EVENT_H\s0" 4 |
1746 | .IX Item "EV_EVENT_H" |
2716 | .IX Item "EV_EVENT_H" |
1747 | Similarly to \f(CW\*(C`EV_H\*(C'\fR, this macro can be used to override \fIevent.c\fR's idea |
2717 | Similarly to \f(CW\*(C`EV_H\*(C'\fR, this macro can be used to override \fIevent.c\fR's idea |
1748 | of how the \fIevent.h\fR header can be found. |
2718 | of how the \fIevent.h\fR header can be found, the dfeault is \f(CW"event.h"\fR. |
1749 | .IP "\s-1EV_PROTOTYPES\s0" 4 |
2719 | .IP "\s-1EV_PROTOTYPES\s0" 4 |
1750 | .IX Item "EV_PROTOTYPES" |
2720 | .IX Item "EV_PROTOTYPES" |
1751 | If defined to be \f(CW0\fR, then \fIev.h\fR will not define any function |
2721 | If defined to be \f(CW0\fR, then \fIev.h\fR will not define any function |
1752 | prototypes, but still define all the structs and other symbols. This is |
2722 | prototypes, but still define all the structs and other symbols. This is |
1753 | occasionally useful if you want to provide your own wrapper functions |
2723 | occasionally useful if you want to provide your own wrapper functions |
… | |
… | |
1757 | If undefined or defined to \f(CW1\fR, then all event-loop-specific functions |
2727 | If undefined or defined to \f(CW1\fR, then all event-loop-specific functions |
1758 | will have the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument, and you can create |
2728 | will have the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument, and you can create |
1759 | additional independent event loops. Otherwise there will be no support |
2729 | additional independent event loops. Otherwise there will be no support |
1760 | for multiple event loops and there is no first event loop pointer |
2730 | for multiple event loops and there is no first event loop pointer |
1761 | argument. Instead, all functions act on the single default loop. |
2731 | argument. Instead, all functions act on the single default loop. |
|
|
2732 | .IP "\s-1EV_MINPRI\s0" 4 |
|
|
2733 | .IX Item "EV_MINPRI" |
|
|
2734 | .PD 0 |
|
|
2735 | .IP "\s-1EV_MAXPRI\s0" 4 |
|
|
2736 | .IX Item "EV_MAXPRI" |
|
|
2737 | .PD |
|
|
2738 | The range of allowed priorities. \f(CW\*(C`EV_MINPRI\*(C'\fR must be smaller or equal to |
|
|
2739 | \&\f(CW\*(C`EV_MAXPRI\*(C'\fR, but otherwise there are no non-obvious limitations. You can |
|
|
2740 | provide for more priorities by overriding those symbols (usually defined |
|
|
2741 | to be \f(CW\*(C`\-2\*(C'\fR and \f(CW2\fR, respectively). |
|
|
2742 | .Sp |
|
|
2743 | When doing priority-based operations, libev usually has to linearly search |
|
|
2744 | all the priorities, so having many of them (hundreds) uses a lot of space |
|
|
2745 | and time, so using the defaults of five priorities (\-2 .. +2) is usually |
|
|
2746 | fine. |
|
|
2747 | .Sp |
|
|
2748 | If your embedding app does not need any priorities, defining these both to |
|
|
2749 | \&\f(CW0\fR will save some memory and cpu. |
1762 | .IP "\s-1EV_PERIODICS\s0" 4 |
2750 | .IP "\s-1EV_PERIODIC_ENABLE\s0" 4 |
1763 | .IX Item "EV_PERIODICS" |
2751 | .IX Item "EV_PERIODIC_ENABLE" |
1764 | If undefined or defined to be \f(CW1\fR, then periodic timers are supported, |
2752 | If undefined or defined to be \f(CW1\fR, then periodic timers are supported. If |
1765 | otherwise not. This saves a few kb of code. |
2753 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
|
|
2754 | code. |
|
|
2755 | .IP "\s-1EV_IDLE_ENABLE\s0" 4 |
|
|
2756 | .IX Item "EV_IDLE_ENABLE" |
|
|
2757 | If undefined or defined to be \f(CW1\fR, then idle watchers are supported. If |
|
|
2758 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
|
|
2759 | code. |
|
|
2760 | .IP "\s-1EV_EMBED_ENABLE\s0" 4 |
|
|
2761 | .IX Item "EV_EMBED_ENABLE" |
|
|
2762 | If undefined or defined to be \f(CW1\fR, then embed watchers are supported. If |
|
|
2763 | defined to be \f(CW0\fR, then they are not. |
|
|
2764 | .IP "\s-1EV_STAT_ENABLE\s0" 4 |
|
|
2765 | .IX Item "EV_STAT_ENABLE" |
|
|
2766 | If undefined or defined to be \f(CW1\fR, then stat watchers are supported. If |
|
|
2767 | defined to be \f(CW0\fR, then they are not. |
|
|
2768 | .IP "\s-1EV_FORK_ENABLE\s0" 4 |
|
|
2769 | .IX Item "EV_FORK_ENABLE" |
|
|
2770 | If undefined or defined to be \f(CW1\fR, then fork watchers are supported. If |
|
|
2771 | defined to be \f(CW0\fR, then they are not. |
|
|
2772 | .IP "\s-1EV_MINIMAL\s0" 4 |
|
|
2773 | .IX Item "EV_MINIMAL" |
|
|
2774 | If you need to shave off some kilobytes of code at the expense of some |
|
|
2775 | speed, define this symbol to \f(CW1\fR. Currently only used for gcc to override |
|
|
2776 | some inlining decisions, saves roughly 30% codesize of amd64. |
|
|
2777 | .IP "\s-1EV_PID_HASHSIZE\s0" 4 |
|
|
2778 | .IX Item "EV_PID_HASHSIZE" |
|
|
2779 | \&\f(CW\*(C`ev_child\*(C'\fR watchers use a small hash table to distribute workload by |
|
|
2780 | pid. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), usually more |
|
|
2781 | than enough. If you need to manage thousands of children you might want to |
|
|
2782 | increase this value (\fImust\fR be a power of two). |
|
|
2783 | .IP "\s-1EV_INOTIFY_HASHSIZE\s0" 4 |
|
|
2784 | .IX Item "EV_INOTIFY_HASHSIZE" |
|
|
2785 | \&\f(CW\*(C`ev_stat\*(C'\fR watchers use a small hash table to distribute workload by |
|
|
2786 | inotify watch id. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), |
|
|
2787 | usually more than enough. If you need to manage thousands of \f(CW\*(C`ev_stat\*(C'\fR |
|
|
2788 | watchers you might want to increase this value (\fImust\fR be a power of |
|
|
2789 | two). |
1766 | .IP "\s-1EV_COMMON\s0" 4 |
2790 | .IP "\s-1EV_COMMON\s0" 4 |
1767 | .IX Item "EV_COMMON" |
2791 | .IX Item "EV_COMMON" |
1768 | By default, all watchers have a \f(CW\*(C`void *data\*(C'\fR member. By redefining |
2792 | By default, all watchers have a \f(CW\*(C`void *data\*(C'\fR member. By redefining |
1769 | this macro to a something else you can include more and other types of |
2793 | this macro to a something else you can include more and other types of |
1770 | members. You have to define it each time you include one of the files, |
2794 | members. You have to define it each time you include one of the files, |
… | |
… | |
1775 | .Vb 3 |
2799 | .Vb 3 |
1776 | \& #define EV_COMMON \e |
2800 | \& #define EV_COMMON \e |
1777 | \& SV *self; /* contains this struct */ \e |
2801 | \& SV *self; /* contains this struct */ \e |
1778 | \& SV *cb_sv, *fh /* note no trailing ";" */ |
2802 | \& SV *cb_sv, *fh /* note no trailing ";" */ |
1779 | .Ve |
2803 | .Ve |
1780 | .IP "\s-1EV_CB_DECLARE\s0(type)" 4 |
2804 | .IP "\s-1EV_CB_DECLARE\s0 (type)" 4 |
1781 | .IX Item "EV_CB_DECLARE(type)" |
2805 | .IX Item "EV_CB_DECLARE (type)" |
1782 | .PD 0 |
2806 | .PD 0 |
1783 | .IP "\s-1EV_CB_INVOKE\s0(watcher,revents)" 4 |
2807 | .IP "\s-1EV_CB_INVOKE\s0 (watcher, revents)" 4 |
1784 | .IX Item "EV_CB_INVOKE(watcher,revents)" |
2808 | .IX Item "EV_CB_INVOKE (watcher, revents)" |
1785 | .IP "ev_set_cb(ev,cb)" 4 |
2809 | .IP "ev_set_cb (ev, cb)" 4 |
1786 | .IX Item "ev_set_cb(ev,cb)" |
2810 | .IX Item "ev_set_cb (ev, cb)" |
1787 | .PD |
2811 | .PD |
1788 | Can be used to change the callback member declaration in each watcher, |
2812 | Can be used to change the callback member declaration in each watcher, |
1789 | and the way callbacks are invoked and set. Must expand to a struct member |
2813 | and the way callbacks are invoked and set. Must expand to a struct member |
1790 | definition and a statement, respectively. See the \fIev.v\fR header file for |
2814 | definition and a statement, respectively. See the \fIev.h\fR header file for |
1791 | their default definitions. One possible use for overriding these is to |
2815 | their default definitions. One possible use for overriding these is to |
1792 | avoid the ev_loop pointer as first argument in all cases, or to use method |
2816 | avoid the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument in all cases, or to use |
1793 | calls instead of plain function calls in \*(C+. |
2817 | method calls instead of plain function calls in \*(C+. |
|
|
2818 | .Sh "\s-1EXPORTED\s0 \s-1API\s0 \s-1SYMBOLS\s0" |
|
|
2819 | .IX Subsection "EXPORTED API SYMBOLS" |
|
|
2820 | If you need to re-export the \s-1API\s0 (e.g. via a dll) and you need a list of |
|
|
2821 | exported symbols, you can use the provided \fISymbol.*\fR files which list |
|
|
2822 | all public symbols, one per line: |
|
|
2823 | .Sp |
|
|
2824 | .Vb 2 |
|
|
2825 | \& Symbols.ev for libev proper |
|
|
2826 | \& Symbols.event for the libevent emulation |
|
|
2827 | .Ve |
|
|
2828 | .Sp |
|
|
2829 | This can also be used to rename all public symbols to avoid clashes with |
|
|
2830 | multiple versions of libev linked together (which is obviously bad in |
|
|
2831 | itself, but sometimes it is inconvinient to avoid this). |
|
|
2832 | .Sp |
|
|
2833 | A sed command like this will create wrapper \f(CW\*(C`#define\*(C'\fR's that you need to |
|
|
2834 | include before including \fIev.h\fR: |
|
|
2835 | .Sp |
|
|
2836 | .Vb 1 |
|
|
2837 | \& <Symbols.ev sed -e "s/.*/#define & myprefix_&/" >wrap.h |
|
|
2838 | .Ve |
|
|
2839 | .Sp |
|
|
2840 | This would create a file \fIwrap.h\fR which essentially looks like this: |
|
|
2841 | .Sp |
|
|
2842 | .Vb 4 |
|
|
2843 | \& #define ev_backend myprefix_ev_backend |
|
|
2844 | \& #define ev_check_start myprefix_ev_check_start |
|
|
2845 | \& #define ev_check_stop myprefix_ev_check_stop |
|
|
2846 | \& ... |
|
|
2847 | .Ve |
1794 | .Sh "\s-1EXAMPLES\s0" |
2848 | .Sh "\s-1EXAMPLES\s0" |
1795 | .IX Subsection "EXAMPLES" |
2849 | .IX Subsection "EXAMPLES" |
1796 | For a real-world example of a program the includes libev |
2850 | For a real-world example of a program the includes libev |
1797 | verbatim, you can have a look at the \s-1EV\s0 perl module |
2851 | verbatim, you can have a look at the \s-1EV\s0 perl module |
1798 | (<http://software.schmorp.de/pkg/EV.html>). It has the libev files in |
2852 | (<http://software.schmorp.de/pkg/EV.html>). It has the libev files in |
… | |
… | |
1800 | interface) and \fI\s-1EV\s0.xs\fR (implementation) files. Only the \fI\s-1EV\s0.xs\fR file |
2854 | interface) and \fI\s-1EV\s0.xs\fR (implementation) files. Only the \fI\s-1EV\s0.xs\fR file |
1801 | will be compiled. It is pretty complex because it provides its own header |
2855 | will be compiled. It is pretty complex because it provides its own header |
1802 | file. |
2856 | file. |
1803 | .Sp |
2857 | .Sp |
1804 | The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file |
2858 | The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file |
1805 | that everybody includes and which overrides some autoconf choices: |
2859 | that everybody includes and which overrides some configure choices: |
1806 | .Sp |
2860 | .Sp |
1807 | .Vb 4 |
2861 | .Vb 9 |
|
|
2862 | \& #define EV_MINIMAL 1 |
1808 | \& #define EV_USE_POLL 0 |
2863 | \& #define EV_USE_POLL 0 |
1809 | \& #define EV_MULTIPLICITY 0 |
2864 | \& #define EV_MULTIPLICITY 0 |
1810 | \& #define EV_PERIODICS 0 |
2865 | \& #define EV_PERIODIC_ENABLE 0 |
|
|
2866 | \& #define EV_STAT_ENABLE 0 |
|
|
2867 | \& #define EV_FORK_ENABLE 0 |
1811 | \& #define EV_CONFIG_H <config.h> |
2868 | \& #define EV_CONFIG_H <config.h> |
|
|
2869 | \& #define EV_MINPRI 0 |
|
|
2870 | \& #define EV_MAXPRI 0 |
1812 | .Ve |
2871 | .Ve |
1813 | .Sp |
2872 | .Sp |
1814 | .Vb 1 |
2873 | .Vb 1 |
1815 | \& #include "ev++.h" |
2874 | \& #include "ev++.h" |
1816 | .Ve |
2875 | .Ve |
… | |
… | |
1819 | .Sp |
2878 | .Sp |
1820 | .Vb 2 |
2879 | .Vb 2 |
1821 | \& #include "ev_cpp.h" |
2880 | \& #include "ev_cpp.h" |
1822 | \& #include "ev.c" |
2881 | \& #include "ev.c" |
1823 | .Ve |
2882 | .Ve |
|
|
2883 | .SH "COMPLEXITIES" |
|
|
2884 | .IX Header "COMPLEXITIES" |
|
|
2885 | In this section the complexities of (many of) the algorithms used inside |
|
|
2886 | libev will be explained. For complexity discussions about backends see the |
|
|
2887 | documentation for \f(CW\*(C`ev_default_init\*(C'\fR. |
|
|
2888 | .Sp |
|
|
2889 | All of the following are about amortised time: If an array needs to be |
|
|
2890 | extended, libev needs to realloc and move the whole array, but this |
|
|
2891 | happens asymptotically never with higher number of elements, so O(1) might |
|
|
2892 | mean it might do a lengthy realloc operation in rare cases, but on average |
|
|
2893 | it is much faster and asymptotically approaches constant time. |
|
|
2894 | .RS 4 |
|
|
2895 | .IP "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" 4 |
|
|
2896 | .IX Item "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" |
|
|
2897 | This means that, when you have a watcher that triggers in one hour and |
|
|
2898 | there are 100 watchers that would trigger before that then inserting will |
|
|
2899 | have to skip roughly seven (\f(CW\*(C`ld 100\*(C'\fR) of these watchers. |
|
|
2900 | .IP "Changing timer/periodic watchers (by autorepeat or calling again): O(log skipped_other_timers)" 4 |
|
|
2901 | .IX Item "Changing timer/periodic watchers (by autorepeat or calling again): O(log skipped_other_timers)" |
|
|
2902 | That means that changing a timer costs less than removing/adding them |
|
|
2903 | as only the relative motion in the event queue has to be paid for. |
|
|
2904 | .IP "Starting io/check/prepare/idle/signal/child watchers: O(1)" 4 |
|
|
2905 | .IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)" |
|
|
2906 | These just add the watcher into an array or at the head of a list. |
|
|
2907 | .IP "Stopping check/prepare/idle watchers: O(1)" 4 |
|
|
2908 | .IX Item "Stopping check/prepare/idle watchers: O(1)" |
|
|
2909 | .PD 0 |
|
|
2910 | .IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % \s-1EV_PID_HASHSIZE\s0))" 4 |
|
|
2911 | .IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))" |
|
|
2912 | .PD |
|
|
2913 | These watchers are stored in lists then need to be walked to find the |
|
|
2914 | correct watcher to remove. The lists are usually short (you don't usually |
|
|
2915 | have many watchers waiting for the same fd or signal). |
|
|
2916 | .IP "Finding the next timer in each loop iteration: O(1)" 4 |
|
|
2917 | .IX Item "Finding the next timer in each loop iteration: O(1)" |
|
|
2918 | By virtue of using a binary heap, the next timer is always found at the |
|
|
2919 | beginning of the storage array. |
|
|
2920 | .IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4 |
|
|
2921 | .IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" |
|
|
2922 | A change means an I/O watcher gets started or stopped, which requires |
|
|
2923 | libev to recalculate its status (and possibly tell the kernel, depending |
|
|
2924 | on backend and wether \f(CW\*(C`ev_io_set\*(C'\fR was used). |
|
|
2925 | .IP "Activating one watcher (putting it into the pending state): O(1)" 4 |
|
|
2926 | .IX Item "Activating one watcher (putting it into the pending state): O(1)" |
|
|
2927 | .PD 0 |
|
|
2928 | .IP "Priority handling: O(number_of_priorities)" 4 |
|
|
2929 | .IX Item "Priority handling: O(number_of_priorities)" |
|
|
2930 | .PD |
|
|
2931 | Priorities are implemented by allocating some space for each |
|
|
2932 | priority. When doing priority-based operations, libev usually has to |
|
|
2933 | linearly search all the priorities, but starting/stopping and activating |
|
|
2934 | watchers becomes O(1) w.r.t. prioritiy handling. |
|
|
2935 | .RE |
|
|
2936 | .RS 4 |
1824 | .SH "AUTHOR" |
2937 | .SH "AUTHOR" |
1825 | .IX Header "AUTHOR" |
2938 | .IX Header "AUTHOR" |
1826 | Marc Lehmann <libev@schmorp.de>. |
2939 | Marc Lehmann <libev@schmorp.de>. |