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129 | .\" ======================================================================== |
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133 | .\" |
131 | .IX Title ""<STANDARD INPUT>" 1" |
134 | .IX Title "EV 1" |
132 | .TH "<STANDARD INPUT>" 1 "2007-11-24" "perl v5.8.8" "User Contributed Perl Documentation" |
135 | .TH EV 1 "2008-01-28" "perl v5.10.0" "User Contributed Perl Documentation" |
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138 | .if n .ad l |
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139 | .nh |
133 | .SH "NAME" |
140 | .SH "NAME" |
134 | libev \- a high performance full\-featured event loop written in C |
141 | libev \- a high performance full\-featured event loop written in C |
135 | .SH "SYNOPSIS" |
142 | .SH "SYNOPSIS" |
136 | .IX Header "SYNOPSIS" |
143 | .IX Header "SYNOPSIS" |
137 | .Vb 1 |
144 | .Vb 1 |
138 | \& #include <ev.h> |
145 | \& #include <ev.h> |
139 | .Ve |
146 | .Ve |
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147 | .Sh "\s-1EXAMPLE\s0 \s-1PROGRAM\s0" |
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148 | .IX Subsection "EXAMPLE PROGRAM" |
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149 | .Vb 1 |
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150 | \& #include <ev.h> |
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151 | \& |
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152 | \& ev_io stdin_watcher; |
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153 | \& ev_timer timeout_watcher; |
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154 | \& |
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155 | \& /* called when data readable on stdin */ |
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156 | \& static void |
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157 | \& stdin_cb (EV_P_ struct ev_io *w, int revents) |
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158 | \& { |
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159 | \& /* puts ("stdin ready"); */ |
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160 | \& ev_io_stop (EV_A_ w); /* just a syntax example */ |
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161 | \& ev_unloop (EV_A_ EVUNLOOP_ALL); /* leave all loop calls */ |
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162 | \& } |
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163 | \& |
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164 | \& static void |
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165 | \& timeout_cb (EV_P_ struct ev_timer *w, int revents) |
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166 | \& { |
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167 | \& /* puts ("timeout"); */ |
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168 | \& ev_unloop (EV_A_ EVUNLOOP_ONE); /* leave one loop call */ |
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169 | \& } |
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170 | \& |
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171 | \& int |
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172 | \& main (void) |
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173 | \& { |
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174 | \& struct ev_loop *loop = ev_default_loop (0); |
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175 | \& |
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176 | \& /* initialise an io watcher, then start it */ |
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177 | \& ev_io_init (&stdin_watcher, stdin_cb, /*STDIN_FILENO*/ 0, EV_READ); |
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178 | \& ev_io_start (loop, &stdin_watcher); |
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179 | \& |
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180 | \& /* simple non\-repeating 5.5 second timeout */ |
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181 | \& ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.); |
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182 | \& ev_timer_start (loop, &timeout_watcher); |
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183 | \& |
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184 | \& /* loop till timeout or data ready */ |
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185 | \& ev_loop (loop, 0); |
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186 | \& |
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187 | \& return 0; |
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188 | \& } |
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189 | .Ve |
140 | .SH "DESCRIPTION" |
190 | .SH "DESCRIPTION" |
141 | .IX Header "DESCRIPTION" |
191 | .IX Header "DESCRIPTION" |
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192 | The newest version of this document is also available as a html-formatted |
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193 | web page you might find easier to navigate when reading it for the first |
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194 | time: <http://cvs.schmorp.de/libev/ev.html>. |
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195 | .PP |
142 | Libev is an event loop: you register interest in certain events (such as a |
196 | 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 |
197 | file descriptor being readable or a timeout occurring), and it will manage |
144 | these event sources and provide your program with events. |
198 | these event sources and provide your program with events. |
145 | .PP |
199 | .PP |
146 | To do this, it must take more or less complete control over your process |
200 | 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 |
201 | (or thread) by executing the \fIevent loop\fR handler, and will then |
148 | communicate events via a callback mechanism. |
202 | communicate events via a callback mechanism. |
149 | .PP |
203 | .PP |
150 | You register interest in certain events by registering so-called \fIevent |
204 | You register interest in certain events by registering so-called \fIevent |
151 | watchers\fR, which are relatively small C structures you initialise with the |
205 | 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 |
206 | details of the event, and then hand it over to libev by \fIstarting\fR the |
153 | watcher. |
207 | watcher. |
154 | .SH "FEATURES" |
208 | .Sh "\s-1FEATURES\s0" |
155 | .IX Header "FEATURES" |
209 | .IX Subsection "FEATURES" |
156 | Libev supports select, poll, the linux-specific epoll and the bsd-specific |
210 | 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 |
211 | 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 |
212 | 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 |
213 | (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 |
214 | with customised rescheduling (\f(CW\*(C`ev_periodic\*(C'\fR), synchronous signals |
161 | fast (see this benchmark comparing |
215 | (\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). |
216 | watchers dealing with the event loop mechanism itself (\f(CW\*(C`ev_idle\*(C'\fR, |
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217 | \&\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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218 | file watchers (\f(CW\*(C`ev_stat\*(C'\fR) and even limited support for fork events |
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219 | (\f(CW\*(C`ev_fork\*(C'\fR). |
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220 | .PP |
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221 | It also is quite fast (see this |
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222 | benchmark comparing it to libevent |
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223 | for example). |
163 | .SH "CONVENTIONS" |
224 | .Sh "\s-1CONVENTIONS\s0" |
164 | .IX Header "CONVENTIONS" |
225 | .IX Subsection "CONVENTIONS" |
165 | Libev is very configurable. In this manual the default configuration |
226 | Libev is very configurable. In this manual the default configuration will |
166 | will be described, which supports multiple event loops. For more info |
227 | be described, which supports multiple event loops. For more info about |
167 | about various configuration options please have a look at the file |
228 | 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 |
229 | this manual. If libev was configured without support for multiple event |
169 | support for multiple event loops, then all functions taking an initial |
230 | 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) |
231 | (which is always of type \f(CW\*(C`struct ev_loop *\*(C'\fR) will not have this argument. |
171 | will not have this argument. |
232 | .Sh "\s-1TIME\s0 \s-1REPRESENTATION\s0" |
172 | .SH "TIME REPRESENTATION" |
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173 | .IX Header "TIME REPRESENTATION" |
233 | .IX Subsection "TIME REPRESENTATION" |
174 | Libev represents time as a single floating point number, representing the |
234 | Libev represents time as a single floating point number, representing the |
175 | (fractional) number of seconds since the (\s-1POSIX\s0) epoch (somewhere near |
235 | (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 |
236 | 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 |
237 | 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 |
238 | 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. |
239 | it, you should treat it as some floatingpoint value. Unlike the name |
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240 | component \f(CW\*(C`stamp\*(C'\fR might indicate, it is also used for time differences |
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241 | throughout libev. |
180 | .SH "GLOBAL FUNCTIONS" |
242 | .SH "GLOBAL FUNCTIONS" |
181 | .IX Header "GLOBAL FUNCTIONS" |
243 | .IX Header "GLOBAL FUNCTIONS" |
182 | These functions can be called anytime, even before initialising the |
244 | These functions can be called anytime, even before initialising the |
183 | library in any way. |
245 | library in any way. |
184 | .IP "ev_tstamp ev_time ()" 4 |
246 | .IP "ev_tstamp ev_time ()" 4 |
185 | .IX Item "ev_tstamp ev_time ()" |
247 | .IX Item "ev_tstamp ev_time ()" |
186 | Returns the current time as libev would use it. Please note that the |
248 | 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 |
249 | \&\f(CW\*(C`ev_now\*(C'\fR function is usually faster and also often returns the timestamp |
188 | you actually want to know. |
250 | you actually want to know. |
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251 | .IP "ev_sleep (ev_tstamp interval)" 4 |
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252 | .IX Item "ev_sleep (ev_tstamp interval)" |
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253 | Sleep for the given interval: The current thread will be blocked until |
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254 | either it is interrupted or the given time interval has passed. Basically |
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255 | this is a subsecond-resolution \f(CW\*(C`sleep ()\*(C'\fR. |
189 | .IP "int ev_version_major ()" 4 |
256 | .IP "int ev_version_major ()" 4 |
190 | .IX Item "int ev_version_major ()" |
257 | .IX Item "int ev_version_major ()" |
191 | .PD 0 |
258 | .PD 0 |
192 | .IP "int ev_version_minor ()" 4 |
259 | .IP "int ev_version_minor ()" 4 |
193 | .IX Item "int ev_version_minor ()" |
260 | .IX Item "int ev_version_minor ()" |
194 | .PD |
261 | .PD |
195 | You can find out the major and minor version numbers of the library |
262 | 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 |
263 | 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 |
264 | \&\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 |
265 | 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. |
266 | version of the library your program was compiled against. |
200 | .Sp |
267 | .Sp |
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268 | These version numbers refer to the \s-1ABI\s0 version of the library, not the |
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269 | release version. |
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270 | .Sp |
201 | Usually, it's a good idea to terminate if the major versions mismatch, |
271 | Usually, it's a good idea to terminate if the major versions mismatch, |
202 | as this indicates an incompatible change. Minor versions are usually |
272 | as this indicates an incompatible change. Minor versions are usually |
203 | compatible to older versions, so a larger minor version alone is usually |
273 | compatible to older versions, so a larger minor version alone is usually |
204 | not a problem. |
274 | not a problem. |
205 | .Sp |
275 | .Sp |
206 | Example: make sure we haven't accidentally been linked against the wrong |
276 | Example: Make sure we haven't accidentally been linked against the wrong |
207 | version: |
277 | version. |
208 | .Sp |
278 | .Sp |
209 | .Vb 3 |
279 | .Vb 3 |
210 | \& assert (("libev version mismatch", |
280 | \& assert (("libev version mismatch", |
211 | \& ev_version_major () == EV_VERSION_MAJOR |
281 | \& ev_version_major () == EV_VERSION_MAJOR |
212 | \& && ev_version_minor () >= EV_VERSION_MINOR)); |
282 | \& && ev_version_minor () >= EV_VERSION_MINOR)); |
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234 | (assuming you know what you are doing). This is the set of backends that |
304 | (assuming you know what you are doing). This is the set of backends that |
235 | libev will probe for if you specify no backends explicitly. |
305 | libev will probe for if you specify no backends explicitly. |
236 | .IP "unsigned int ev_embeddable_backends ()" 4 |
306 | .IP "unsigned int ev_embeddable_backends ()" 4 |
237 | .IX Item "unsigned int ev_embeddable_backends ()" |
307 | .IX Item "unsigned int ev_embeddable_backends ()" |
238 | Returns the set of backends that are embeddable in other event loops. This |
308 | Returns the set of backends that are embeddable in other event loops. This |
239 | is the theoretical, all\-platform, value. To find which backends |
309 | is the theoretical, all-platform, value. To find which backends |
240 | might be supported on the current system, you would need to look at |
310 | might be supported on the current system, you would need to look at |
241 | \&\f(CW\*(C`ev_embeddable_backends () & ev_supported_backends ()\*(C'\fR, likewise for |
311 | \&\f(CW\*(C`ev_embeddable_backends () & ev_supported_backends ()\*(C'\fR, likewise for |
242 | recommended ones. |
312 | recommended ones. |
243 | .Sp |
313 | .Sp |
244 | See the description of \f(CW\*(C`ev_embed\*(C'\fR watchers for more info. |
314 | 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 |
315 | .IP "ev_set_allocator (void *(*cb)(void *ptr, long size))" 4 |
246 | .IX Item "ev_set_allocator (void *(*cb)(void *ptr, long size))" |
316 | .IX Item "ev_set_allocator (void *(*cb)(void *ptr, long size))" |
247 | Sets the allocation function to use (the prototype is similar to the |
317 | Sets the allocation function to use (the prototype is similar \- the |
248 | realloc C function, the semantics are identical). It is used to allocate |
318 | 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 |
319 | 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 |
320 | memory needs to be allocated, the library might abort or take some |
251 | destructive action. The default is your system realloc function. |
321 | potentially destructive action. The default is your system realloc |
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322 | function. |
252 | .Sp |
323 | .Sp |
253 | You could override this function in high-availability programs to, say, |
324 | 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, |
325 | 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. |
326 | or even to sleep a while and retry until some memory is available. |
256 | .Sp |
327 | .Sp |
257 | Example: replace the libev allocator with one that waits a bit and then |
328 | Example: Replace the libev allocator with one that waits a bit and then |
258 | retries: better than mine). |
329 | retries). |
259 | .Sp |
330 | .Sp |
260 | .Vb 6 |
331 | .Vb 6 |
261 | \& static void * |
332 | \& static void * |
262 | \& persistent_realloc (void *ptr, long size) |
333 | \& persistent_realloc (void *ptr, size_t size) |
263 | \& { |
334 | \& { |
264 | \& for (;;) |
335 | \& for (;;) |
265 | \& { |
336 | \& { |
266 | \& void *newptr = realloc (ptr, size); |
337 | \& void *newptr = realloc (ptr, size); |
267 | .Ve |
338 | \& |
268 | .Sp |
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269 | .Vb 2 |
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270 | \& if (newptr) |
339 | \& if (newptr) |
271 | \& return newptr; |
340 | \& return newptr; |
272 | .Ve |
341 | \& |
273 | .Sp |
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274 | .Vb 3 |
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275 | \& sleep (60); |
342 | \& sleep (60); |
276 | \& } |
343 | \& } |
277 | \& } |
344 | \& } |
278 | .Ve |
345 | \& |
279 | .Sp |
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280 | .Vb 2 |
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281 | \& ... |
346 | \& ... |
282 | \& ev_set_allocator (persistent_realloc); |
347 | \& ev_set_allocator (persistent_realloc); |
283 | .Ve |
348 | .Ve |
284 | .IP "ev_set_syserr_cb (void (*cb)(const char *msg));" 4 |
349 | .IP "ev_set_syserr_cb (void (*cb)(const char *msg));" 4 |
285 | .IX Item "ev_set_syserr_cb (void (*cb)(const char *msg));" |
350 | .IX Item "ev_set_syserr_cb (void (*cb)(const char *msg));" |
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289 | callback is set, then libev will expect it to remedy the sitution, no |
354 | 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 |
355 | 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 |
356 | requested operation, or, if the condition doesn't go away, do bad stuff |
292 | (such as abort). |
357 | (such as abort). |
293 | .Sp |
358 | .Sp |
294 | Example: do the same thing as libev does internally: |
359 | Example: This is basically the same thing that libev does internally, too. |
295 | .Sp |
360 | .Sp |
296 | .Vb 6 |
361 | .Vb 6 |
297 | \& static void |
362 | \& static void |
298 | \& fatal_error (const char *msg) |
363 | \& fatal_error (const char *msg) |
299 | \& { |
364 | \& { |
300 | \& perror (msg); |
365 | \& perror (msg); |
301 | \& abort (); |
366 | \& abort (); |
302 | \& } |
367 | \& } |
303 | .Ve |
368 | \& |
304 | .Sp |
|
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305 | .Vb 2 |
|
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306 | \& ... |
369 | \& ... |
307 | \& ev_set_syserr_cb (fatal_error); |
370 | \& ev_set_syserr_cb (fatal_error); |
308 | .Ve |
371 | .Ve |
309 | .SH "FUNCTIONS CONTROLLING THE EVENT LOOP" |
372 | .SH "FUNCTIONS CONTROLLING THE EVENT LOOP" |
310 | .IX Header "FUNCTIONS CONTROLLING THE EVENT LOOP" |
373 | .IX Header "FUNCTIONS CONTROLLING THE EVENT LOOP" |
… | |
… | |
325 | false. If it already was initialised it simply returns it (and ignores the |
388 | false. If it already was initialised it simply returns it (and ignores the |
326 | flags. If that is troubling you, check \f(CW\*(C`ev_backend ()\*(C'\fR afterwards). |
389 | flags. If that is troubling you, check \f(CW\*(C`ev_backend ()\*(C'\fR afterwards). |
327 | .Sp |
390 | .Sp |
328 | If you don't know what event loop to use, use the one returned from this |
391 | If you don't know what event loop to use, use the one returned from this |
329 | function. |
392 | function. |
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393 | .Sp |
|
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394 | The default loop is the only loop that can handle \f(CW\*(C`ev_signal\*(C'\fR and |
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395 | \&\f(CW\*(C`ev_child\*(C'\fR watchers, and to do this, it always registers a handler |
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396 | for \f(CW\*(C`SIGCHLD\*(C'\fR. If this is a problem for your app you can either |
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397 | create a dynamic loop with \f(CW\*(C`ev_loop_new\*(C'\fR that doesn't do that, or you |
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398 | can simply overwrite the \f(CW\*(C`SIGCHLD\*(C'\fR signal handler \fIafter\fR calling |
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399 | \&\f(CW\*(C`ev_default_init\*(C'\fR. |
330 | .Sp |
400 | .Sp |
331 | The flags argument can be used to specify special behaviour or specific |
401 | The flags argument can be used to specify special behaviour or specific |
332 | backends to use, and is usually specified as \f(CW0\fR (or \f(CW\*(C`EVFLAG_AUTO\*(C'\fR). |
402 | backends to use, and is usually specified as \f(CW0\fR (or \f(CW\*(C`EVFLAG_AUTO\*(C'\fR). |
333 | .Sp |
403 | .Sp |
334 | The following flags are supported: |
404 | The following flags are supported: |
… | |
… | |
345 | or setgid) then libev will \fInot\fR look at the environment variable |
415 | or setgid) then libev will \fInot\fR look at the environment variable |
346 | \&\f(CW\*(C`LIBEV_FLAGS\*(C'\fR. Otherwise (the default), this environment variable will |
416 | \&\f(CW\*(C`LIBEV_FLAGS\*(C'\fR. Otherwise (the default), this environment variable will |
347 | override the flags completely if it is found in the environment. This is |
417 | override the flags completely if it is found in the environment. This is |
348 | useful to try out specific backends to test their performance, or to work |
418 | useful to try out specific backends to test their performance, or to work |
349 | around bugs. |
419 | around bugs. |
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420 | .ie n .IP """EVFLAG_FORKCHECK""" 4 |
|
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421 | .el .IP "\f(CWEVFLAG_FORKCHECK\fR" 4 |
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422 | .IX Item "EVFLAG_FORKCHECK" |
|
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423 | Instead of calling \f(CW\*(C`ev_default_fork\*(C'\fR or \f(CW\*(C`ev_loop_fork\*(C'\fR manually after |
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424 | a fork, you can also make libev check for a fork in each iteration by |
|
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425 | enabling this flag. |
|
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426 | .Sp |
|
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427 | This works by calling \f(CW\*(C`getpid ()\*(C'\fR on every iteration of the loop, |
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428 | and thus this might slow down your event loop if you do a lot of loop |
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429 | iterations and little real work, but is usually not noticeable (on my |
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430 | Linux system for example, \f(CW\*(C`getpid\*(C'\fR is actually a simple 5\-insn sequence |
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431 | without a syscall and thus \fIvery\fR fast, but my Linux system also has |
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432 | \&\f(CW\*(C`pthread_atfork\*(C'\fR which is even faster). |
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433 | .Sp |
|
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434 | The big advantage of this flag is that you can forget about fork (and |
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435 | forget about forgetting to tell libev about forking) when you use this |
|
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436 | flag. |
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437 | .Sp |
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438 | This flag setting cannot be overriden or specified in the \f(CW\*(C`LIBEV_FLAGS\*(C'\fR |
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439 | environment variable. |
350 | .ie n .IP """EVBACKEND_SELECT"" (value 1, portable select backend)" 4 |
440 | .ie n .IP """EVBACKEND_SELECT"" (value 1, portable select backend)" 4 |
351 | .el .IP "\f(CWEVBACKEND_SELECT\fR (value 1, portable select backend)" 4 |
441 | .el .IP "\f(CWEVBACKEND_SELECT\fR (value 1, portable select backend)" 4 |
352 | .IX Item "EVBACKEND_SELECT (value 1, portable select backend)" |
442 | .IX Item "EVBACKEND_SELECT (value 1, portable select backend)" |
353 | This is your standard \fIselect\fR\|(2) backend. Not \fIcompletely\fR standard, as |
443 | This is your standard \fIselect\fR\|(2) backend. Not \fIcompletely\fR standard, as |
354 | libev tries to roll its own fd_set with no limits on the number of fds, |
444 | libev tries to roll its own fd_set with no limits on the number of fds, |
355 | but if that fails, expect a fairly low limit on the number of fds when |
445 | 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 |
446 | using this backend. It doesn't scale too well (O(highest_fd)), but its |
357 | the fastest backend for a low number of fds. |
447 | usually the fastest backend for a low number of (low-numbered :) fds. |
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448 | .Sp |
|
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449 | To get good performance out of this backend you need a high amount of |
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450 | parallelity (most of the file descriptors should be busy). If you are |
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451 | writing a server, you should \f(CW\*(C`accept ()\*(C'\fR in a loop to accept as many |
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452 | connections as possible during one iteration. You might also want to have |
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453 | a look at \f(CW\*(C`ev_set_io_collect_interval ()\*(C'\fR to increase the amount of |
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454 | readyness notifications you get per iteration. |
358 | .ie n .IP """EVBACKEND_POLL"" (value 2, poll backend, available everywhere except on windows)" 4 |
455 | .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 |
456 | .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)" |
457 | .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 |
458 | 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 |
459 | 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 |
460 | 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). |
461 | considerably with a lot of inactive fds). It scales similarly to select, |
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462 | i.e. O(total_fds). See the entry for \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR, above, for |
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463 | performance tips. |
365 | .ie n .IP """EVBACKEND_EPOLL"" (value 4, Linux)" 4 |
464 | .ie n .IP """EVBACKEND_EPOLL"" (value 4, Linux)" 4 |
366 | .el .IP "\f(CWEVBACKEND_EPOLL\fR (value 4, Linux)" 4 |
465 | .el .IP "\f(CWEVBACKEND_EPOLL\fR (value 4, Linux)" 4 |
367 | .IX Item "EVBACKEND_EPOLL (value 4, Linux)" |
466 | .IX Item "EVBACKEND_EPOLL (value 4, Linux)" |
368 | For few fds, this backend is a bit little slower than poll and select, |
467 | 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 |
468 | 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 |
469 | like O(total_fds) where n is the total number of fds (or the highest fd), |
371 | either O(1) or O(active_fds). |
470 | epoll scales either O(1) or O(active_fds). The epoll design has a number |
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471 | of shortcomings, such as silently dropping events in some hard-to-detect |
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472 | cases and rewiring a syscall per fd change, no fork support and bad |
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473 | support for dup. |
372 | .Sp |
474 | .Sp |
373 | While stopping and starting an I/O watcher in the same iteration will |
475 | 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 |
476 | 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 |
477 | (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 |
478 | 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. |
479 | very well if you register events for both fds. |
378 | .Sp |
480 | .Sp |
379 | Please note that epoll sometimes generates spurious notifications, so you |
481 | 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 |
482 | need to use non-blocking I/O or other means to avoid blocking when no data |
381 | (or space) is available. |
483 | (or space) is available. |
|
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484 | .Sp |
|
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485 | Best performance from this backend is achieved by not unregistering all |
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486 | watchers for a file descriptor until it has been closed, if possible, i.e. |
|
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487 | keep at least one watcher active per fd at all times. |
|
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488 | .Sp |
|
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489 | While nominally embeddeble in other event loops, this feature is broken in |
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490 | all kernel versions tested so far. |
382 | .ie n .IP """EVBACKEND_KQUEUE"" (value 8, most \s-1BSD\s0 clones)" 4 |
491 | .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 |
492 | .el .IP "\f(CWEVBACKEND_KQUEUE\fR (value 8, most \s-1BSD\s0 clones)" 4 |
384 | .IX Item "EVBACKEND_KQUEUE (value 8, most BSD clones)" |
493 | .IX Item "EVBACKEND_KQUEUE (value 8, most BSD clones)" |
385 | Kqueue deserves special mention, as at the time of this writing, it |
494 | 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 |
495 | 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 |
496 | with anything but sockets and pipes, except on Darwin, where of course |
388 | completely useless). For this reason its not being \*(L"autodetected\*(R" |
497 | 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 |
498 | unless you explicitly specify it explicitly in the flags (i.e. using |
390 | \&\f(CW\*(C`EVBACKEND_KQUEUE\*(C'\fR). |
499 | \&\f(CW\*(C`EVBACKEND_KQUEUE\*(C'\fR) or libev was compiled on a known-to-be-good (\-enough) |
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500 | system like NetBSD. |
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501 | .Sp |
|
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502 | You still can embed kqueue into a normal poll or select backend and use it |
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503 | only for sockets (after having made sure that sockets work with kqueue on |
|
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504 | the target platform). See \f(CW\*(C`ev_embed\*(C'\fR watchers for more info. |
391 | .Sp |
505 | .Sp |
392 | It scales in the same way as the epoll backend, but the interface to the |
506 | 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 |
507 | 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 |
508 | 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 |
509 | 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. |
510 | two event changes per incident, support for \f(CW\*(C`fork ()\*(C'\fR is very bad and it |
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511 | drops fds silently in similarly hard-to-detect cases. |
|
|
512 | .Sp |
|
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513 | This backend usually performs well under most conditions. |
|
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514 | .Sp |
|
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515 | While nominally embeddable in other event loops, this doesn't work |
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516 | everywhere, so you might need to test for this. And since it is broken |
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517 | almost everywhere, you should only use it when you have a lot of sockets |
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518 | (for which it usually works), by embedding it into another event loop |
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519 | (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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520 | sockets. |
397 | .ie n .IP """EVBACKEND_DEVPOLL"" (value 16, Solaris 8)" 4 |
521 | .ie n .IP """EVBACKEND_DEVPOLL"" (value 16, Solaris 8)" 4 |
398 | .el .IP "\f(CWEVBACKEND_DEVPOLL\fR (value 16, Solaris 8)" 4 |
522 | .el .IP "\f(CWEVBACKEND_DEVPOLL\fR (value 16, Solaris 8)" 4 |
399 | .IX Item "EVBACKEND_DEVPOLL (value 16, Solaris 8)" |
523 | .IX Item "EVBACKEND_DEVPOLL (value 16, Solaris 8)" |
400 | This is not implemented yet (and might never be). |
524 | This is not implemented yet (and might never be, unless you send me an |
|
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525 | implementation). According to reports, \f(CW\*(C`/dev/poll\*(C'\fR only supports sockets |
|
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526 | and is not embeddable, which would limit the usefulness of this backend |
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527 | immensely. |
401 | .ie n .IP """EVBACKEND_PORT"" (value 32, Solaris 10)" 4 |
528 | .ie n .IP """EVBACKEND_PORT"" (value 32, Solaris 10)" 4 |
402 | .el .IP "\f(CWEVBACKEND_PORT\fR (value 32, Solaris 10)" 4 |
529 | .el .IP "\f(CWEVBACKEND_PORT\fR (value 32, Solaris 10)" 4 |
403 | .IX Item "EVBACKEND_PORT (value 32, Solaris 10)" |
530 | .IX Item "EVBACKEND_PORT (value 32, Solaris 10)" |
404 | This uses the Solaris 10 port mechanism. As with everything on Solaris, |
531 | 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)). |
532 | it's really slow, but it still scales very well (O(active_fds)). |
406 | .Sp |
533 | .Sp |
407 | Please note that solaris ports can result in a lot of spurious |
534 | 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 |
535 | notifications, so you need to use non-blocking I/O or other means to avoid |
409 | blocking when no data (or space) is available. |
536 | blocking when no data (or space) is available. |
|
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537 | .Sp |
|
|
538 | While this backend scales well, it requires one system call per active |
|
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539 | file descriptor per loop iteration. For small and medium numbers of file |
|
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540 | descriptors a \*(L"slow\*(R" \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR or \f(CW\*(C`EVBACKEND_POLL\*(C'\fR backend |
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541 | might perform better. |
|
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542 | .Sp |
|
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543 | On the positive side, ignoring the spurious readyness notifications, this |
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544 | backend actually performed to specification in all tests and is fully |
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545 | embeddable, which is a rare feat among the OS-specific backends. |
410 | .ie n .IP """EVBACKEND_ALL""" 4 |
546 | .ie n .IP """EVBACKEND_ALL""" 4 |
411 | .el .IP "\f(CWEVBACKEND_ALL\fR" 4 |
547 | .el .IP "\f(CWEVBACKEND_ALL\fR" 4 |
412 | .IX Item "EVBACKEND_ALL" |
548 | .IX Item "EVBACKEND_ALL" |
413 | Try all backends (even potentially broken ones that wouldn't be tried |
549 | 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 |
550 | 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. |
551 | \&\f(CW\*(C`EVBACKEND_ALL & ~EVBACKEND_KQUEUE\*(C'\fR. |
|
|
552 | .Sp |
|
|
553 | It is definitely not recommended to use this flag. |
416 | .RE |
554 | .RE |
417 | .RS 4 |
555 | .RS 4 |
418 | .Sp |
556 | .Sp |
419 | If one or more of these are ored into the flags value, then only these |
557 | 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 |
558 | backends will be tried (in the reverse order as listed here). If none are |
421 | specified, most compiled-in backend will be tried, usually in reverse |
559 | specified, all backends in \f(CW\*(C`ev_recommended_backends ()\*(C'\fR will be tried. |
422 | order of their flag values :) |
|
|
423 | .Sp |
560 | .Sp |
424 | The most typical usage is like this: |
561 | The most typical usage is like this: |
425 | .Sp |
562 | .Sp |
426 | .Vb 2 |
563 | .Vb 2 |
427 | \& if (!ev_default_loop (0)) |
564 | \& if (!ev_default_loop (0)) |
… | |
… | |
448 | Similar to \f(CW\*(C`ev_default_loop\*(C'\fR, but always creates a new event loop that is |
585 | 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 |
586 | 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 |
587 | 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). |
588 | undefined behaviour (or a failed assertion if assertions are enabled). |
452 | .Sp |
589 | .Sp |
453 | Example: try to create a event loop that uses epoll and nothing else. |
590 | Example: Try to create a event loop that uses epoll and nothing else. |
454 | .Sp |
591 | .Sp |
455 | .Vb 3 |
592 | .Vb 3 |
456 | \& struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
593 | \& struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
457 | \& if (!epoller) |
594 | \& if (!epoller) |
458 | \& fatal ("no epoll found here, maybe it hides under your chair"); |
595 | \& fatal ("no epoll found here, maybe it hides under your chair"); |
… | |
… | |
462 | Destroys the default loop again (frees all memory and kernel state |
599 | 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 |
600 | 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 |
601 | 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 |
602 | responsibility to either stop all watchers cleanly yoursef \fIbefore\fR |
466 | calling this function, or cope with the fact afterwards (which is usually |
603 | 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 |
604 | the easiest thing, you can just ignore the watchers and/or \f(CW\*(C`free ()\*(C'\fR them |
468 | for example). |
605 | for example). |
|
|
606 | .Sp |
|
|
607 | Note that certain global state, such as signal state, will not be freed by |
|
|
608 | this function, and related watchers (such as signal and child watchers) |
|
|
609 | would need to be stopped manually. |
|
|
610 | .Sp |
|
|
611 | In general it is not advisable to call this function except in the |
|
|
612 | rare occasion where you really need to free e.g. the signal handling |
|
|
613 | pipe fds. If you need dynamically allocated loops it is better to use |
|
|
614 | \&\f(CW\*(C`ev_loop_new\*(C'\fR and \f(CW\*(C`ev_loop_destroy\*(C'\fR). |
469 | .IP "ev_loop_destroy (loop)" 4 |
615 | .IP "ev_loop_destroy (loop)" 4 |
470 | .IX Item "ev_loop_destroy (loop)" |
616 | .IX Item "ev_loop_destroy (loop)" |
471 | Like \f(CW\*(C`ev_default_destroy\*(C'\fR, but destroys an event loop created by an |
617 | 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. |
618 | earlier call to \f(CW\*(C`ev_loop_new\*(C'\fR. |
473 | .IP "ev_default_fork ()" 4 |
619 | .IP "ev_default_fork ()" 4 |
474 | .IX Item "ev_default_fork ()" |
620 | .IX Item "ev_default_fork ()" |
|
|
621 | This function sets a flag that causes subsequent \f(CW\*(C`ev_loop\*(C'\fR iterations |
475 | This function reinitialises the kernel state for backends that have |
622 | to reinitialise the kernel state for backends that have one. Despite the |
476 | one. Despite the name, you can call it anytime, but it makes most sense |
623 | name, you can call it anytime, but it makes most sense after forking, in |
477 | after forking, in either the parent or child process (or both, but that |
624 | the child process (or both child and parent, but that again makes little |
478 | again makes little sense). |
625 | sense). You \fImust\fR call it in the child before using any of the libev |
|
|
626 | functions, and it will only take effect at the next \f(CW\*(C`ev_loop\*(C'\fR iteration. |
479 | .Sp |
627 | .Sp |
480 | You \fImust\fR call this function in the child process after forking if and |
628 | On the other hand, you only need to call this function in the child |
481 | only if you want to use the event library in both processes. If you just |
629 | process if and only if you want to use the event library in the child. If |
482 | fork+exec, you don't have to call it. |
630 | you just fork+exec, you don't have to call it at all. |
483 | .Sp |
631 | .Sp |
484 | The function itself is quite fast and it's usually not a problem to call |
632 | The function itself is quite fast and it's usually not a problem to call |
485 | it just in case after a fork. To make this easy, the function will fit in |
633 | it just in case after a fork. To make this easy, the function will fit in |
486 | quite nicely into a call to \f(CW\*(C`pthread_atfork\*(C'\fR: |
634 | quite nicely into a call to \f(CW\*(C`pthread_atfork\*(C'\fR: |
487 | .Sp |
635 | .Sp |
488 | .Vb 1 |
636 | .Vb 1 |
489 | \& pthread_atfork (0, 0, ev_default_fork); |
637 | \& pthread_atfork (0, 0, ev_default_fork); |
490 | .Ve |
638 | .Ve |
491 | .Sp |
|
|
492 | At the moment, \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR and \f(CW\*(C`EVBACKEND_POLL\*(C'\fR are safe to use |
|
|
493 | without calling this function, so if you force one of those backends you |
|
|
494 | do not need to care. |
|
|
495 | .IP "ev_loop_fork (loop)" 4 |
639 | .IP "ev_loop_fork (loop)" 4 |
496 | .IX Item "ev_loop_fork (loop)" |
640 | .IX Item "ev_loop_fork (loop)" |
497 | Like \f(CW\*(C`ev_default_fork\*(C'\fR, but acts on an event loop created by |
641 | 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 |
642 | \&\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. |
643 | after fork, and how you do this is entirely your own problem. |
|
|
644 | .IP "unsigned int ev_loop_count (loop)" 4 |
|
|
645 | .IX Item "unsigned int ev_loop_count (loop)" |
|
|
646 | Returns the count of loop iterations for the loop, which is identical to |
|
|
647 | the number of times libev did poll for new events. It starts at \f(CW0\fR and |
|
|
648 | happily wraps around with enough iterations. |
|
|
649 | .Sp |
|
|
650 | This value can sometimes be useful as a generation counter of sorts (it |
|
|
651 | \&\*(L"ticks\*(R" the number of loop iterations), as it roughly corresponds with |
|
|
652 | \&\f(CW\*(C`ev_prepare\*(C'\fR and \f(CW\*(C`ev_check\*(C'\fR calls. |
500 | .IP "unsigned int ev_backend (loop)" 4 |
653 | .IP "unsigned int ev_backend (loop)" 4 |
501 | .IX Item "unsigned int ev_backend (loop)" |
654 | .IX Item "unsigned int ev_backend (loop)" |
502 | Returns one of the \f(CW\*(C`EVBACKEND_*\*(C'\fR flags indicating the event backend in |
655 | Returns one of the \f(CW\*(C`EVBACKEND_*\*(C'\fR flags indicating the event backend in |
503 | use. |
656 | use. |
504 | .IP "ev_tstamp ev_now (loop)" 4 |
657 | .IP "ev_tstamp ev_now (loop)" 4 |
505 | .IX Item "ev_tstamp ev_now (loop)" |
658 | .IX Item "ev_tstamp ev_now (loop)" |
506 | Returns the current \*(L"event loop time\*(R", which is the time the event loop |
659 | 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 |
660 | 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 |
661 | 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 |
662 | 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). |
663 | event occurring (or more correctly, libev finding out about it). |
511 | .IP "ev_loop (loop, int flags)" 4 |
664 | .IP "ev_loop (loop, int flags)" 4 |
512 | .IX Item "ev_loop (loop, int flags)" |
665 | .IX Item "ev_loop (loop, int flags)" |
513 | Finally, this is it, the event handler. This function usually is called |
666 | 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 |
667 | after you initialised all your watchers and you want to start handling |
515 | events. |
668 | events. |
… | |
… | |
535 | libev watchers. However, a pair of \f(CW\*(C`ev_prepare\*(C'\fR/\f(CW\*(C`ev_check\*(C'\fR watchers is |
688 | 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. |
689 | usually a better approach for this kind of thing. |
537 | .Sp |
690 | .Sp |
538 | Here are the gory details of what \f(CW\*(C`ev_loop\*(C'\fR does: |
691 | Here are the gory details of what \f(CW\*(C`ev_loop\*(C'\fR does: |
539 | .Sp |
692 | .Sp |
540 | .Vb 18 |
693 | .Vb 10 |
541 | \& * If there are no active watchers (reference count is zero), return. |
694 | \& \- Before the first iteration, call any pending watchers. |
542 | \& - Queue prepare watchers and then call all outstanding watchers. |
695 | \& * If EVFLAG_FORKCHECK was used, check for a fork. |
|
|
696 | \& \- If a fork was detected, queue and call all fork watchers. |
|
|
697 | \& \- Queue and call all prepare watchers. |
543 | \& - If we have been forked, recreate the kernel state. |
698 | \& \- If we have been forked, recreate the kernel state. |
544 | \& - Update the kernel state with all outstanding changes. |
699 | \& \- Update the kernel state with all outstanding changes. |
545 | \& - Update the "event loop time". |
700 | \& \- Update the "event loop time". |
546 | \& - Calculate for how long to block. |
701 | \& \- Calculate for how long to sleep or block, if at all |
|
|
702 | \& (active idle watchers, EVLOOP_NONBLOCK or not having |
|
|
703 | \& any active watchers at all will result in not sleeping). |
|
|
704 | \& \- Sleep if the I/O and timer collect interval say so. |
547 | \& - Block the process, waiting for any events. |
705 | \& \- Block the process, waiting for any events. |
548 | \& - Queue all outstanding I/O (fd) events. |
706 | \& \- Queue all outstanding I/O (fd) events. |
549 | \& - Update the "event loop time" and do time jump handling. |
707 | \& \- Update the "event loop time" and do time jump handling. |
550 | \& - Queue all outstanding timers. |
708 | \& \- Queue all outstanding timers. |
551 | \& - Queue all outstanding periodics. |
709 | \& \- Queue all outstanding periodics. |
552 | \& - If no events are pending now, queue all idle watchers. |
710 | \& \- If no events are pending now, queue all idle watchers. |
553 | \& - Queue all check watchers. |
711 | \& \- Queue all check watchers. |
554 | \& - Call all queued watchers in reverse order (i.e. check watchers first). |
712 | \& \- Call all queued watchers in reverse order (i.e. check watchers first). |
555 | \& Signals and child watchers are implemented as I/O watchers, and will |
713 | \& Signals and child watchers are implemented as I/O watchers, and will |
556 | \& be handled here by queueing them when their watcher gets executed. |
714 | \& be handled here by queueing them when their watcher gets executed. |
557 | \& - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
715 | \& \- If ev_unloop has been called, or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
558 | \& were used, return, otherwise continue with step *. |
716 | \& were used, or there are no active watchers, return, otherwise |
|
|
717 | \& continue with step *. |
559 | .Ve |
718 | .Ve |
560 | .Sp |
719 | .Sp |
561 | Example: queue some jobs and then loop until no events are outsanding |
720 | Example: Queue some jobs and then loop until no events are outstanding |
562 | anymore. |
721 | anymore. |
563 | .Sp |
722 | .Sp |
564 | .Vb 4 |
723 | .Vb 4 |
565 | \& ... queue jobs here, make sure they register event watchers as long |
724 | \& ... 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..) |
725 | \& ... as they still have work to do (even an idle watcher will do..) |
… | |
… | |
571 | .IX Item "ev_unloop (loop, how)" |
730 | .IX Item "ev_unloop (loop, how)" |
572 | Can be used to make a call to \f(CW\*(C`ev_loop\*(C'\fR return early (but only after it |
731 | Can be used to make a call to \f(CW\*(C`ev_loop\*(C'\fR return early (but only after it |
573 | has processed all outstanding events). The \f(CW\*(C`how\*(C'\fR argument must be either |
732 | has processed all outstanding events). The \f(CW\*(C`how\*(C'\fR argument must be either |
574 | \&\f(CW\*(C`EVUNLOOP_ONE\*(C'\fR, which will make the innermost \f(CW\*(C`ev_loop\*(C'\fR call return, or |
733 | \&\f(CW\*(C`EVUNLOOP_ONE\*(C'\fR, which will make the innermost \f(CW\*(C`ev_loop\*(C'\fR call return, or |
575 | \&\f(CW\*(C`EVUNLOOP_ALL\*(C'\fR, which will make all nested \f(CW\*(C`ev_loop\*(C'\fR calls return. |
734 | \&\f(CW\*(C`EVUNLOOP_ALL\*(C'\fR, which will make all nested \f(CW\*(C`ev_loop\*(C'\fR calls return. |
|
|
735 | .Sp |
|
|
736 | This \*(L"unloop state\*(R" will be cleared when entering \f(CW\*(C`ev_loop\*(C'\fR again. |
576 | .IP "ev_ref (loop)" 4 |
737 | .IP "ev_ref (loop)" 4 |
577 | .IX Item "ev_ref (loop)" |
738 | .IX Item "ev_ref (loop)" |
578 | .PD 0 |
739 | .PD 0 |
579 | .IP "ev_unref (loop)" 4 |
740 | .IP "ev_unref (loop)" 4 |
580 | .IX Item "ev_unref (loop)" |
741 | .IX Item "ev_unref (loop)" |
… | |
… | |
586 | returning, \fIev_unref()\fR after starting, and \fIev_ref()\fR before stopping it. For |
747 | returning, \fIev_unref()\fR after starting, and \fIev_ref()\fR before stopping it. For |
587 | example, libev itself uses this for its internal signal pipe: It is not |
748 | example, libev itself uses this for its internal signal pipe: It is not |
588 | visible to the libev user and should not keep \f(CW\*(C`ev_loop\*(C'\fR from exiting if |
749 | 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 |
750 | 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 |
751 | 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. |
752 | libraries. Just remember to \fIunref after start\fR and \fIref before stop\fR |
|
|
753 | (but only if the watcher wasn't active before, or was active before, |
|
|
754 | respectively). |
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: |
… | |
… | |
616 | \& static void my_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
816 | \& static void my_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
617 | \& { |
817 | \& { |
618 | \& ev_io_stop (w); |
818 | \& ev_io_stop (w); |
619 | \& ev_unloop (loop, EVUNLOOP_ALL); |
819 | \& ev_unloop (loop, EVUNLOOP_ALL); |
620 | \& } |
820 | \& } |
621 | .Ve |
821 | \& |
622 | .PP |
|
|
623 | .Vb 6 |
|
|
624 | \& struct ev_loop *loop = ev_default_loop (0); |
822 | \& struct ev_loop *loop = ev_default_loop (0); |
625 | \& struct ev_io stdin_watcher; |
823 | \& struct ev_io stdin_watcher; |
626 | \& ev_init (&stdin_watcher, my_cb); |
824 | \& ev_init (&stdin_watcher, my_cb); |
627 | \& ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ); |
825 | \& ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ); |
628 | \& ev_io_start (loop, &stdin_watcher); |
826 | \& ev_io_start (loop, &stdin_watcher); |
… | |
… | |
684 | The signal specified in the \f(CW\*(C`ev_signal\*(C'\fR watcher has been received by a thread. |
882 | 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 |
883 | .ie n .IP """EV_CHILD""" 4 |
686 | .el .IP "\f(CWEV_CHILD\fR" 4 |
884 | .el .IP "\f(CWEV_CHILD\fR" 4 |
687 | .IX Item "EV_CHILD" |
885 | .IX Item "EV_CHILD" |
688 | The pid specified in the \f(CW\*(C`ev_child\*(C'\fR watcher has received a status change. |
886 | The pid specified in the \f(CW\*(C`ev_child\*(C'\fR watcher has received a status change. |
|
|
887 | .ie n .IP """EV_STAT""" 4 |
|
|
888 | .el .IP "\f(CWEV_STAT\fR" 4 |
|
|
889 | .IX Item "EV_STAT" |
|
|
890 | The path specified in the \f(CW\*(C`ev_stat\*(C'\fR watcher changed its attributes somehow. |
689 | .ie n .IP """EV_IDLE""" 4 |
891 | .ie n .IP """EV_IDLE""" 4 |
690 | .el .IP "\f(CWEV_IDLE\fR" 4 |
892 | .el .IP "\f(CWEV_IDLE\fR" 4 |
691 | .IX Item "EV_IDLE" |
893 | .IX Item "EV_IDLE" |
692 | The \f(CW\*(C`ev_idle\*(C'\fR watcher has determined that you have nothing better to do. |
894 | 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 |
895 | .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 |
905 | \&\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 |
906 | 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 |
907 | 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 |
908 | (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). |
909 | \&\f(CW\*(C`ev_loop\*(C'\fR from blocking). |
|
|
910 | .ie n .IP """EV_EMBED""" 4 |
|
|
911 | .el .IP "\f(CWEV_EMBED\fR" 4 |
|
|
912 | .IX Item "EV_EMBED" |
|
|
913 | The embedded event loop specified in the \f(CW\*(C`ev_embed\*(C'\fR watcher needs attention. |
|
|
914 | .ie n .IP """EV_FORK""" 4 |
|
|
915 | .el .IP "\f(CWEV_FORK\fR" 4 |
|
|
916 | .IX Item "EV_FORK" |
|
|
917 | The event loop has been resumed in the child process after fork (see |
|
|
918 | \&\f(CW\*(C`ev_fork\*(C'\fR). |
708 | .ie n .IP """EV_ERROR""" 4 |
919 | .ie n .IP """EV_ERROR""" 4 |
709 | .el .IP "\f(CWEV_ERROR\fR" 4 |
920 | .el .IP "\f(CWEV_ERROR\fR" 4 |
710 | .IX Item "EV_ERROR" |
921 | .IX Item "EV_ERROR" |
711 | An unspecified error has occured, the watcher has been stopped. This might |
922 | An unspecified error has occured, the watcher has been stopped. This might |
712 | happen because the watcher could not be properly started because libev |
923 | happen because the watcher could not be properly started because libev |
… | |
… | |
717 | Libev will usually signal a few \*(L"dummy\*(R" events together with an error, |
928 | Libev will usually signal a few \*(L"dummy\*(R" events together with an error, |
718 | for example it might indicate that a fd is readable or writable, and if |
929 | for example it might indicate that a fd is readable or writable, and if |
719 | your callbacks is well-written it can just attempt the operation and cope |
930 | your callbacks is well-written it can just attempt the operation and cope |
720 | with the error from \fIread()\fR or \fIwrite()\fR. This will not work in multithreaded |
931 | with the error from \fIread()\fR or \fIwrite()\fR. This will not work in multithreaded |
721 | programs, though, so beware. |
932 | programs, though, so beware. |
722 | .Sh "\s-1SUMMARY\s0 \s-1OF\s0 \s-1GENERIC\s0 \s-1WATCHER\s0 \s-1FUNCTIONS\s0" |
933 | .Sh "\s-1GENERIC\s0 \s-1WATCHER\s0 \s-1FUNCTIONS\s0" |
723 | .IX Subsection "SUMMARY OF GENERIC WATCHER FUNCTIONS" |
934 | .IX Subsection "GENERIC WATCHER FUNCTIONS" |
724 | In the following description, \f(CW\*(C`TYPE\*(C'\fR stands for the watcher type, |
935 | In the following description, \f(CW\*(C`TYPE\*(C'\fR stands for the watcher type, |
725 | e.g. \f(CW\*(C`timer\*(C'\fR for \f(CW\*(C`ev_timer\*(C'\fR watchers and \f(CW\*(C`io\*(C'\fR for \f(CW\*(C`ev_io\*(C'\fR watchers. |
936 | e.g. \f(CW\*(C`timer\*(C'\fR for \f(CW\*(C`ev_timer\*(C'\fR watchers and \f(CW\*(C`io\*(C'\fR for \f(CW\*(C`ev_io\*(C'\fR watchers. |
726 | .ie n .IP """ev_init"" (ev_TYPE *watcher, callback)" 4 |
937 | .ie n .IP """ev_init"" (ev_TYPE *watcher, callback)" 4 |
727 | .el .IP "\f(CWev_init\fR (ev_TYPE *watcher, callback)" 4 |
938 | .el .IP "\f(CWev_init\fR (ev_TYPE *watcher, callback)" 4 |
728 | .IX Item "ev_init (ev_TYPE *watcher, callback)" |
939 | .IX Item "ev_init (ev_TYPE *watcher, callback)" |
… | |
… | |
734 | which rolls both calls into one. |
945 | which rolls both calls into one. |
735 | .Sp |
946 | .Sp |
736 | You can reinitialise a watcher at any time as long as it has been stopped |
947 | You can reinitialise a watcher at any time as long as it has been stopped |
737 | (or never started) and there are no pending events outstanding. |
948 | (or never started) and there are no pending events outstanding. |
738 | .Sp |
949 | .Sp |
739 | The callbakc is always of type \f(CW\*(C`void (*)(ev_loop *loop, ev_TYPE *watcher, |
950 | The callback is always of type \f(CW\*(C`void (*)(ev_loop *loop, ev_TYPE *watcher, |
740 | int revents)\*(C'\fR. |
951 | int revents)\*(C'\fR. |
741 | .ie n .IP """ev_TYPE_set"" (ev_TYPE *, [args])" 4 |
952 | .ie n .IP """ev_TYPE_set"" (ev_TYPE *, [args])" 4 |
742 | .el .IP "\f(CWev_TYPE_set\fR (ev_TYPE *, [args])" 4 |
953 | .el .IP "\f(CWev_TYPE_set\fR (ev_TYPE *, [args])" 4 |
743 | .IX Item "ev_TYPE_set (ev_TYPE *, [args])" |
954 | .IX Item "ev_TYPE_set (ev_TYPE *, [args])" |
744 | This macro initialises the type-specific parts of a watcher. You need to |
955 | This macro initialises the type-specific parts of a watcher. You need to |
… | |
… | |
777 | .IP "bool ev_is_pending (ev_TYPE *watcher)" 4 |
988 | .IP "bool ev_is_pending (ev_TYPE *watcher)" 4 |
778 | .IX Item "bool ev_is_pending (ev_TYPE *watcher)" |
989 | .IX Item "bool ev_is_pending (ev_TYPE *watcher)" |
779 | Returns a true value iff the watcher is pending, (i.e. it has outstanding |
990 | 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 |
991 | 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 |
992 | 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 |
993 | \&\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). |
994 | make sure the watcher is available to libev (e.g. you cannot \f(CW\*(C`free ()\*(C'\fR |
|
|
995 | it). |
784 | .IP "callback = ev_cb (ev_TYPE *watcher)" 4 |
996 | .IP "callback ev_cb (ev_TYPE *watcher)" 4 |
785 | .IX Item "callback = ev_cb (ev_TYPE *watcher)" |
997 | .IX Item "callback ev_cb (ev_TYPE *watcher)" |
786 | Returns the callback currently set on the watcher. |
998 | Returns the callback currently set on the watcher. |
787 | .IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 |
999 | .IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 |
788 | .IX Item "ev_cb_set (ev_TYPE *watcher, callback)" |
1000 | .IX Item "ev_cb_set (ev_TYPE *watcher, callback)" |
789 | Change the callback. You can change the callback at virtually any time |
1001 | Change the callback. You can change the callback at virtually any time |
790 | (modulo threads). |
1002 | (modulo threads). |
|
|
1003 | .IP "ev_set_priority (ev_TYPE *watcher, priority)" 4 |
|
|
1004 | .IX Item "ev_set_priority (ev_TYPE *watcher, priority)" |
|
|
1005 | .PD 0 |
|
|
1006 | .IP "int ev_priority (ev_TYPE *watcher)" 4 |
|
|
1007 | .IX Item "int ev_priority (ev_TYPE *watcher)" |
|
|
1008 | .PD |
|
|
1009 | Set and query the priority of the watcher. The priority is a small |
|
|
1010 | integer between \f(CW\*(C`EV_MAXPRI\*(C'\fR (default: \f(CW2\fR) and \f(CW\*(C`EV_MINPRI\*(C'\fR |
|
|
1011 | (default: \f(CW\*(C`\-2\*(C'\fR). Pending watchers with higher priority will be invoked |
|
|
1012 | before watchers with lower priority, but priority will not keep watchers |
|
|
1013 | from being executed (except for \f(CW\*(C`ev_idle\*(C'\fR watchers). |
|
|
1014 | .Sp |
|
|
1015 | This means that priorities are \fIonly\fR used for ordering callback |
|
|
1016 | invocation after new events have been received. This is useful, for |
|
|
1017 | example, to reduce latency after idling, or more often, to bind two |
|
|
1018 | watchers on the same event and make sure one is called first. |
|
|
1019 | .Sp |
|
|
1020 | If you need to suppress invocation when higher priority events are pending |
|
|
1021 | you need to look at \f(CW\*(C`ev_idle\*(C'\fR watchers, which provide this functionality. |
|
|
1022 | .Sp |
|
|
1023 | You \fImust not\fR change the priority of a watcher as long as it is active or |
|
|
1024 | pending. |
|
|
1025 | .Sp |
|
|
1026 | The default priority used by watchers when no priority has been set is |
|
|
1027 | always \f(CW0\fR, which is supposed to not be too high and not be too low :). |
|
|
1028 | .Sp |
|
|
1029 | Setting a priority outside the range of \f(CW\*(C`EV_MINPRI\*(C'\fR to \f(CW\*(C`EV_MAXPRI\*(C'\fR is |
|
|
1030 | fine, as long as you do not mind that the priority value you query might |
|
|
1031 | or might not have been adjusted to be within valid range. |
|
|
1032 | .IP "ev_invoke (loop, ev_TYPE *watcher, int revents)" 4 |
|
|
1033 | .IX Item "ev_invoke (loop, ev_TYPE *watcher, int revents)" |
|
|
1034 | 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 |
|
|
1035 | \&\f(CW\*(C`loop\*(C'\fR nor \f(CW\*(C`revents\*(C'\fR need to be valid as long as the watcher callback |
|
|
1036 | can deal with that fact. |
|
|
1037 | .IP "int ev_clear_pending (loop, ev_TYPE *watcher)" 4 |
|
|
1038 | .IX Item "int ev_clear_pending (loop, ev_TYPE *watcher)" |
|
|
1039 | If the watcher is pending, this function returns clears its pending status |
|
|
1040 | and returns its \f(CW\*(C`revents\*(C'\fR bitset (as if its callback was invoked). If the |
|
|
1041 | 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" |
1042 | .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" |
1043 | .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 |
1044 | 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 |
1045 | 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 |
1046 | to associate arbitrary data with your watcher. If you need more data and |
… | |
… | |
816 | \& struct my_io *w = (struct my_io *)w_; |
1067 | \& struct my_io *w = (struct my_io *)w_; |
817 | \& ... |
1068 | \& ... |
818 | \& } |
1069 | \& } |
819 | .Ve |
1070 | .Ve |
820 | .PP |
1071 | .PP |
821 | More interesting and less C\-conformant ways of catsing your callback type |
1072 | More interesting and less C\-conformant ways of casting your callback type |
822 | have been omitted.... |
1073 | instead have been omitted. |
|
|
1074 | .PP |
|
|
1075 | Another common scenario is having some data structure with multiple |
|
|
1076 | watchers: |
|
|
1077 | .PP |
|
|
1078 | .Vb 6 |
|
|
1079 | \& struct my_biggy |
|
|
1080 | \& { |
|
|
1081 | \& int some_data; |
|
|
1082 | \& ev_timer t1; |
|
|
1083 | \& ev_timer t2; |
|
|
1084 | \& } |
|
|
1085 | .Ve |
|
|
1086 | .PP |
|
|
1087 | In this case getting the pointer to \f(CW\*(C`my_biggy\*(C'\fR is a bit more complicated, |
|
|
1088 | you need to use \f(CW\*(C`offsetof\*(C'\fR: |
|
|
1089 | .PP |
|
|
1090 | .Vb 1 |
|
|
1091 | \& #include <stddef.h> |
|
|
1092 | \& |
|
|
1093 | \& static void |
|
|
1094 | \& t1_cb (EV_P_ struct ev_timer *w, int revents) |
|
|
1095 | \& { |
|
|
1096 | \& struct my_biggy big = (struct my_biggy * |
|
|
1097 | \& (((char *)w) \- offsetof (struct my_biggy, t1)); |
|
|
1098 | \& } |
|
|
1099 | \& |
|
|
1100 | \& static void |
|
|
1101 | \& t2_cb (EV_P_ struct ev_timer *w, int revents) |
|
|
1102 | \& { |
|
|
1103 | \& struct my_biggy big = (struct my_biggy * |
|
|
1104 | \& (((char *)w) \- offsetof (struct my_biggy, t2)); |
|
|
1105 | \& } |
|
|
1106 | .Ve |
823 | .SH "WATCHER TYPES" |
1107 | .SH "WATCHER TYPES" |
824 | .IX Header "WATCHER TYPES" |
1108 | .IX Header "WATCHER TYPES" |
825 | This section describes each watcher in detail, but will not repeat |
1109 | This section describes each watcher in detail, but will not repeat |
826 | information given in the last section. |
1110 | information given in the last section. Any initialisation/set macros, |
|
|
1111 | functions and members specific to the watcher type are explained. |
|
|
1112 | .PP |
|
|
1113 | Members are additionally marked with either \fI[read\-only]\fR, meaning that, |
|
|
1114 | while the watcher is active, you can look at the member and expect some |
|
|
1115 | sensible content, but you must not modify it (you can modify it while the |
|
|
1116 | watcher is stopped to your hearts content), or \fI[read\-write]\fR, which |
|
|
1117 | means you can expect it to have some sensible content while the watcher |
|
|
1118 | is active, but you can also modify it. Modifying it may not do something |
|
|
1119 | sensible or take immediate effect (or do anything at all), but libev will |
|
|
1120 | not crash or malfunction in any way. |
827 | .ie n .Sh """ev_io"" \- is this file descriptor readable or writable" |
1121 | .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" |
1122 | .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" |
1123 | .IX Subsection "ev_io - is this file descriptor readable or writable?" |
830 | I/O watchers check whether a file descriptor is readable or writable |
1124 | I/O watchers check whether a file descriptor is readable or writable |
831 | in each iteration of the event loop (This behaviour is called |
1125 | in each iteration of the event loop, or, more precisely, when reading |
832 | level-triggering because you keep receiving events as long as the |
1126 | would not block the process and writing would at least be able to write |
833 | condition persists. Remember you can stop the watcher if you don't want to |
1127 | some data. This behaviour is called level-triggering because you keep |
834 | act on the event and neither want to receive future events). |
1128 | receiving events as long as the condition persists. Remember you can stop |
|
|
1129 | the watcher if you don't want to act on the event and neither want to |
|
|
1130 | receive future events. |
835 | .PP |
1131 | .PP |
836 | In general you can register as many read and/or write event watchers per |
1132 | In general you can register as many read and/or write event watchers per |
837 | fd as you want (as long as you don't confuse yourself). Setting all file |
1133 | fd as you want (as long as you don't confuse yourself). Setting all file |
838 | descriptors to non-blocking mode is also usually a good idea (but not |
1134 | descriptors to non-blocking mode is also usually a good idea (but not |
839 | required if you know what you are doing). |
1135 | required if you know what you are doing). |
840 | .PP |
1136 | .PP |
841 | You have to be careful with dup'ed file descriptors, though. Some backends |
|
|
842 | (the linux epoll backend is a notable example) cannot handle dup'ed file |
|
|
843 | descriptors correctly if you register interest in two or more fds pointing |
|
|
844 | to the same underlying file/socket etc. description (that is, they share |
|
|
845 | the same underlying \*(L"file open\*(R"). |
|
|
846 | .PP |
|
|
847 | If you must do this, then force the use of a known-to-be-good backend |
1137 | If you must do this, then force the use of a known-to-be-good backend |
848 | (at the time of this writing, this includes only \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR and |
1138 | (at the time of this writing, this includes only \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR and |
849 | \&\f(CW\*(C`EVBACKEND_POLL\*(C'\fR). |
1139 | \&\f(CW\*(C`EVBACKEND_POLL\*(C'\fR). |
|
|
1140 | .PP |
|
|
1141 | Another thing you have to watch out for is that it is quite easy to |
|
|
1142 | receive \*(L"spurious\*(R" readyness notifications, that is your callback might |
|
|
1143 | be called with \f(CW\*(C`EV_READ\*(C'\fR but a subsequent \f(CW\*(C`read\*(C'\fR(2) will actually block |
|
|
1144 | because there is no data. Not only are some backends known to create a |
|
|
1145 | lot of those (for example solaris ports), it is very easy to get into |
|
|
1146 | this situation even with a relatively standard program structure. Thus |
|
|
1147 | it is best to always use non-blocking I/O: An extra \f(CW\*(C`read\*(C'\fR(2) returning |
|
|
1148 | \&\f(CW\*(C`EAGAIN\*(C'\fR is far preferable to a program hanging until some data arrives. |
|
|
1149 | .PP |
|
|
1150 | If you cannot run the fd in non-blocking mode (for example you should not |
|
|
1151 | play around with an Xlib connection), then you have to seperately re-test |
|
|
1152 | whether a file descriptor is really ready with a known-to-be good interface |
|
|
1153 | such as poll (fortunately in our Xlib example, Xlib already does this on |
|
|
1154 | its own, so its quite safe to use). |
|
|
1155 | .PP |
|
|
1156 | \fIThe special problem of disappearing file descriptors\fR |
|
|
1157 | .IX Subsection "The special problem of disappearing file descriptors" |
|
|
1158 | .PP |
|
|
1159 | Some backends (e.g. kqueue, epoll) need to be told about closing a file |
|
|
1160 | descriptor (either by calling \f(CW\*(C`close\*(C'\fR explicitly or by any other means, |
|
|
1161 | such as \f(CW\*(C`dup\*(C'\fR). The reason is that you register interest in some file |
|
|
1162 | descriptor, but when it goes away, the operating system will silently drop |
|
|
1163 | this interest. If another file descriptor with the same number then is |
|
|
1164 | registered with libev, there is no efficient way to see that this is, in |
|
|
1165 | fact, a different file descriptor. |
|
|
1166 | .PP |
|
|
1167 | To avoid having to explicitly tell libev about such cases, libev follows |
|
|
1168 | the following policy: Each time \f(CW\*(C`ev_io_set\*(C'\fR is being called, libev |
|
|
1169 | will assume that this is potentially a new file descriptor, otherwise |
|
|
1170 | it is assumed that the file descriptor stays the same. That means that |
|
|
1171 | 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 |
|
|
1172 | descriptor even if the file descriptor number itself did not change. |
|
|
1173 | .PP |
|
|
1174 | This is how one would do it normally anyway, the important point is that |
|
|
1175 | the libev application should not optimise around libev but should leave |
|
|
1176 | optimisations to libev. |
|
|
1177 | .PP |
|
|
1178 | \fIThe special problem of dup'ed file descriptors\fR |
|
|
1179 | .IX Subsection "The special problem of dup'ed file descriptors" |
|
|
1180 | .PP |
|
|
1181 | Some backends (e.g. epoll), cannot register events for file descriptors, |
|
|
1182 | but only events for the underlying file descriptions. That means when you |
|
|
1183 | have \f(CW\*(C`dup ()\*(C'\fR'ed file descriptors or weirder constellations, and register |
|
|
1184 | events for them, only one file descriptor might actually receive events. |
|
|
1185 | .PP |
|
|
1186 | There is no workaround possible except not registering events |
|
|
1187 | for potentially \f(CW\*(C`dup ()\*(C'\fR'ed file descriptors, or to resort to |
|
|
1188 | \&\f(CW\*(C`EVBACKEND_SELECT\*(C'\fR or \f(CW\*(C`EVBACKEND_POLL\*(C'\fR. |
|
|
1189 | .PP |
|
|
1190 | \fIThe special problem of fork\fR |
|
|
1191 | .IX Subsection "The special problem of fork" |
|
|
1192 | .PP |
|
|
1193 | Some backends (epoll, kqueue) do not support \f(CW\*(C`fork ()\*(C'\fR at all or exhibit |
|
|
1194 | useless behaviour. Libev fully supports fork, but needs to be told about |
|
|
1195 | it in the child. |
|
|
1196 | .PP |
|
|
1197 | To support fork in your programs, you either have to call |
|
|
1198 | \&\f(CW\*(C`ev_default_fork ()\*(C'\fR or \f(CW\*(C`ev_loop_fork ()\*(C'\fR after a fork in the child, |
|
|
1199 | enable \f(CW\*(C`EVFLAG_FORKCHECK\*(C'\fR, or resort to \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR or |
|
|
1200 | \&\f(CW\*(C`EVBACKEND_POLL\*(C'\fR. |
|
|
1201 | .PP |
|
|
1202 | \fIWatcher-Specific Functions\fR |
|
|
1203 | .IX Subsection "Watcher-Specific Functions" |
850 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
1204 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
851 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
1205 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
852 | .PD 0 |
1206 | .PD 0 |
853 | .IP "ev_io_set (ev_io *, int fd, int events)" 4 |
1207 | .IP "ev_io_set (ev_io *, int fd, int events)" 4 |
854 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
1208 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
855 | .PD |
1209 | .PD |
856 | Configures an \f(CW\*(C`ev_io\*(C'\fR watcher. The fd is the file descriptor to rceeive |
1210 | Configures an \f(CW\*(C`ev_io\*(C'\fR watcher. The \f(CW\*(C`fd\*(C'\fR is the file descriptor to |
857 | events for and events is either \f(CW\*(C`EV_READ\*(C'\fR, \f(CW\*(C`EV_WRITE\*(C'\fR or \f(CW\*(C`EV_READ | |
1211 | rceeive events for and events is either \f(CW\*(C`EV_READ\*(C'\fR, \f(CW\*(C`EV_WRITE\*(C'\fR or |
858 | EV_WRITE\*(C'\fR to receive the given events. |
1212 | \&\f(CW\*(C`EV_READ | EV_WRITE\*(C'\fR to receive the given events. |
859 | .Sp |
1213 | .IP "int fd [read\-only]" 4 |
860 | Please note that most of the more scalable backend mechanisms (for example |
1214 | .IX Item "int fd [read-only]" |
861 | epoll and solaris ports) can result in spurious readyness notifications |
1215 | The file descriptor being watched. |
862 | for file descriptors, so you practically need to use non-blocking I/O (and |
1216 | .IP "int events [read\-only]" 4 |
863 | treat callback invocation as hint only), or retest separately with a safe |
1217 | .IX Item "int events [read-only]" |
864 | interface before doing I/O (XLib can do this), or force the use of either |
1218 | The events being watched. |
865 | \&\f(CW\*(C`EVBACKEND_SELECT\*(C'\fR or \f(CW\*(C`EVBACKEND_POLL\*(C'\fR, which don't suffer from this |
|
|
866 | problem. Also note that it is quite easy to have your callback invoked |
|
|
867 | when the readyness condition is no longer valid even when employing |
|
|
868 | typical ways of handling events, so its a good idea to use non-blocking |
|
|
869 | I/O unconditionally. |
|
|
870 | .PP |
1219 | .PP |
|
|
1220 | \fIExamples\fR |
|
|
1221 | .IX Subsection "Examples" |
|
|
1222 | .PP |
871 | Example: call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well |
1223 | Example: Call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well |
872 | readable, but only once. Since it is likely line\-buffered, you could |
1224 | readable, but only once. Since it is likely line-buffered, you could |
873 | attempt to read a whole line in the callback: |
1225 | attempt to read a whole line in the callback. |
874 | .PP |
1226 | .PP |
875 | .Vb 6 |
1227 | .Vb 6 |
876 | \& static void |
1228 | \& static void |
877 | \& stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
1229 | \& stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
878 | \& { |
1230 | \& { |
879 | \& ev_io_stop (loop, w); |
1231 | \& ev_io_stop (loop, w); |
880 | \& .. read from stdin here (or from w->fd) and haqndle any I/O errors |
1232 | \& .. read from stdin here (or from w\->fd) and haqndle any I/O errors |
881 | \& } |
1233 | \& } |
882 | .Ve |
1234 | \& |
883 | .PP |
|
|
884 | .Vb 6 |
|
|
885 | \& ... |
1235 | \& ... |
886 | \& struct ev_loop *loop = ev_default_init (0); |
1236 | \& struct ev_loop *loop = ev_default_init (0); |
887 | \& struct ev_io stdin_readable; |
1237 | \& struct ev_io stdin_readable; |
888 | \& ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ); |
1238 | \& ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ); |
889 | \& ev_io_start (loop, &stdin_readable); |
1239 | \& ev_io_start (loop, &stdin_readable); |
890 | \& ev_loop (loop, 0); |
1240 | \& ev_loop (loop, 0); |
891 | .Ve |
1241 | .Ve |
892 | .ie n .Sh """ev_timer"" \- relative and optionally recurring timeouts" |
1242 | .ie n .Sh """ev_timer"" \- relative and optionally repeating timeouts" |
893 | .el .Sh "\f(CWev_timer\fP \- relative and optionally recurring timeouts" |
1243 | .el .Sh "\f(CWev_timer\fP \- relative and optionally repeating timeouts" |
894 | .IX Subsection "ev_timer - relative and optionally recurring timeouts" |
1244 | .IX Subsection "ev_timer - relative and optionally repeating timeouts" |
895 | Timer watchers are simple relative timers that generate an event after a |
1245 | Timer watchers are simple relative timers that generate an event after a |
896 | given time, and optionally repeating in regular intervals after that. |
1246 | given time, and optionally repeating in regular intervals after that. |
897 | .PP |
1247 | .PP |
898 | The timers are based on real time, that is, if you register an event that |
1248 | The timers are based on real time, that is, if you register an event that |
899 | times out after an hour and you reset your system clock to last years |
1249 | times out after an hour and you reset your system clock to last years |
… | |
… | |
906 | of the event triggering whatever timeout you are modifying/starting. If |
1256 | of the event triggering whatever timeout you are modifying/starting. If |
907 | you suspect event processing to be delayed and you \fIneed\fR to base the timeout |
1257 | you suspect event processing to be delayed and you \fIneed\fR to base the timeout |
908 | on the current time, use something like this to adjust for this: |
1258 | on the current time, use something like this to adjust for this: |
909 | .PP |
1259 | .PP |
910 | .Vb 1 |
1260 | .Vb 1 |
911 | \& ev_timer_set (&timer, after + ev_now () - ev_time (), 0.); |
1261 | \& ev_timer_set (&timer, after + ev_now () \- ev_time (), 0.); |
912 | .Ve |
1262 | .Ve |
913 | .PP |
1263 | .PP |
914 | The callback is guarenteed to be invoked only when its timeout has passed, |
1264 | The callback is guarenteed to be invoked only when its timeout has passed, |
915 | but if multiple timers become ready during the same loop iteration then |
1265 | but if multiple timers become ready during the same loop iteration then |
916 | order of execution is undefined. |
1266 | order of execution is undefined. |
|
|
1267 | .PP |
|
|
1268 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1269 | .IX Subsection "Watcher-Specific Functions and Data Members" |
917 | .IP "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" 4 |
1270 | .IP "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" 4 |
918 | .IX Item "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" |
1271 | .IX Item "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" |
919 | .PD 0 |
1272 | .PD 0 |
920 | .IP "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)" 4 |
1273 | .IP "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)" 4 |
921 | .IX Item "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)" |
1274 | .IX Item "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)" |
… | |
… | |
933 | .IP "ev_timer_again (loop)" 4 |
1286 | .IP "ev_timer_again (loop)" 4 |
934 | .IX Item "ev_timer_again (loop)" |
1287 | .IX Item "ev_timer_again (loop)" |
935 | This will act as if the timer timed out and restart it again if it is |
1288 | This will act as if the timer timed out and restart it again if it is |
936 | repeating. The exact semantics are: |
1289 | repeating. The exact semantics are: |
937 | .Sp |
1290 | .Sp |
|
|
1291 | If the timer is pending, its pending status is cleared. |
|
|
1292 | .Sp |
938 | If the timer is started but nonrepeating, stop it. |
1293 | If the timer is started but nonrepeating, stop it (as if it timed out). |
939 | .Sp |
1294 | .Sp |
940 | If the timer is repeating, either start it if necessary (with the repeat |
1295 | If the timer is repeating, either start it if necessary (with the |
941 | value), or reset the running timer to the repeat value. |
1296 | \&\f(CW\*(C`repeat\*(C'\fR value), or reset the running timer to the \f(CW\*(C`repeat\*(C'\fR value. |
942 | .Sp |
1297 | .Sp |
943 | This sounds a bit complicated, but here is a useful and typical |
1298 | This sounds a bit complicated, but here is a useful and typical |
944 | example: Imagine you have a tcp connection and you want a so-called idle |
1299 | example: Imagine you have a tcp connection and you want a so-called idle |
945 | timeout, that is, you want to be called when there have been, say, 60 |
1300 | timeout, that is, you want to be called when there have been, say, 60 |
946 | seconds of inactivity on the socket. The easiest way to do this is to |
1301 | seconds of inactivity on the socket. The easiest way to do this is to |
947 | configure an \f(CW\*(C`ev_timer\*(C'\fR with after=repeat=60 and calling ev_timer_again each |
1302 | configure an \f(CW\*(C`ev_timer\*(C'\fR with a \f(CW\*(C`repeat\*(C'\fR value of \f(CW60\fR and then call |
948 | time you successfully read or write some data. If you go into an idle |
1303 | \&\f(CW\*(C`ev_timer_again\*(C'\fR each time you successfully read or write some data. If |
949 | state where you do not expect data to travel on the socket, you can stop |
1304 | you go into an idle state where you do not expect data to travel on the |
950 | the timer, and again will automatically restart it if need be. |
1305 | socket, you can \f(CW\*(C`ev_timer_stop\*(C'\fR the timer, and \f(CW\*(C`ev_timer_again\*(C'\fR will |
|
|
1306 | automatically restart it if need be. |
|
|
1307 | .Sp |
|
|
1308 | That means you can ignore the \f(CW\*(C`after\*(C'\fR value and \f(CW\*(C`ev_timer_start\*(C'\fR |
|
|
1309 | altogether and only ever use the \f(CW\*(C`repeat\*(C'\fR value and \f(CW\*(C`ev_timer_again\*(C'\fR: |
|
|
1310 | .Sp |
|
|
1311 | .Vb 8 |
|
|
1312 | \& ev_timer_init (timer, callback, 0., 5.); |
|
|
1313 | \& ev_timer_again (loop, timer); |
|
|
1314 | \& ... |
|
|
1315 | \& timer\->again = 17.; |
|
|
1316 | \& ev_timer_again (loop, timer); |
|
|
1317 | \& ... |
|
|
1318 | \& timer\->again = 10.; |
|
|
1319 | \& ev_timer_again (loop, timer); |
|
|
1320 | .Ve |
|
|
1321 | .Sp |
|
|
1322 | This is more slightly efficient then stopping/starting the timer each time |
|
|
1323 | you want to modify its timeout value. |
|
|
1324 | .IP "ev_tstamp repeat [read\-write]" 4 |
|
|
1325 | .IX Item "ev_tstamp repeat [read-write]" |
|
|
1326 | The current \f(CW\*(C`repeat\*(C'\fR value. Will be used each time the watcher times out |
|
|
1327 | or \f(CW\*(C`ev_timer_again\*(C'\fR is called and determines the next timeout (if any), |
|
|
1328 | which is also when any modifications are taken into account. |
951 | .PP |
1329 | .PP |
|
|
1330 | \fIExamples\fR |
|
|
1331 | .IX Subsection "Examples" |
|
|
1332 | .PP |
952 | Example: create a timer that fires after 60 seconds. |
1333 | Example: Create a timer that fires after 60 seconds. |
953 | .PP |
1334 | .PP |
954 | .Vb 5 |
1335 | .Vb 5 |
955 | \& static void |
1336 | \& static void |
956 | \& one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1337 | \& one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
957 | \& { |
1338 | \& { |
958 | \& .. one minute over, w is actually stopped right here |
1339 | \& .. one minute over, w is actually stopped right here |
959 | \& } |
1340 | \& } |
960 | .Ve |
1341 | \& |
961 | .PP |
|
|
962 | .Vb 3 |
|
|
963 | \& struct ev_timer mytimer; |
1342 | \& struct ev_timer mytimer; |
964 | \& ev_timer_init (&mytimer, one_minute_cb, 60., 0.); |
1343 | \& ev_timer_init (&mytimer, one_minute_cb, 60., 0.); |
965 | \& ev_timer_start (loop, &mytimer); |
1344 | \& ev_timer_start (loop, &mytimer); |
966 | .Ve |
1345 | .Ve |
967 | .PP |
1346 | .PP |
968 | Example: create a timeout timer that times out after 10 seconds of |
1347 | Example: Create a timeout timer that times out after 10 seconds of |
969 | inactivity. |
1348 | inactivity. |
970 | .PP |
1349 | .PP |
971 | .Vb 5 |
1350 | .Vb 5 |
972 | \& static void |
1351 | \& static void |
973 | \& timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1352 | \& timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
974 | \& { |
1353 | \& { |
975 | \& .. ten seconds without any activity |
1354 | \& .. ten seconds without any activity |
976 | \& } |
1355 | \& } |
977 | .Ve |
1356 | \& |
978 | .PP |
|
|
979 | .Vb 4 |
|
|
980 | \& struct ev_timer mytimer; |
1357 | \& struct ev_timer mytimer; |
981 | \& ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */ |
1358 | \& ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */ |
982 | \& ev_timer_again (&mytimer); /* start timer */ |
1359 | \& ev_timer_again (&mytimer); /* start timer */ |
983 | \& ev_loop (loop, 0); |
1360 | \& ev_loop (loop, 0); |
984 | .Ve |
1361 | \& |
985 | .PP |
|
|
986 | .Vb 3 |
|
|
987 | \& // and in some piece of code that gets executed on any "activity": |
1362 | \& // and in some piece of code that gets executed on any "activity": |
988 | \& // reset the timeout to start ticking again at 10 seconds |
1363 | \& // reset the timeout to start ticking again at 10 seconds |
989 | \& ev_timer_again (&mytimer); |
1364 | \& ev_timer_again (&mytimer); |
990 | .Ve |
1365 | .Ve |
991 | .ie n .Sh """ev_periodic"" \- to cron or not to cron" |
1366 | .ie n .Sh """ev_periodic"" \- to cron or not to cron?" |
992 | .el .Sh "\f(CWev_periodic\fP \- to cron or not to cron" |
1367 | .el .Sh "\f(CWev_periodic\fP \- to cron or not to cron?" |
993 | .IX Subsection "ev_periodic - to cron or not to cron" |
1368 | .IX Subsection "ev_periodic - to cron or not to cron?" |
994 | Periodic watchers are also timers of a kind, but they are very versatile |
1369 | Periodic watchers are also timers of a kind, but they are very versatile |
995 | (and unfortunately a bit complex). |
1370 | (and unfortunately a bit complex). |
996 | .PP |
1371 | .PP |
997 | Unlike \f(CW\*(C`ev_timer\*(C'\fR's, they are not based on real time (or relative time) |
1372 | Unlike \f(CW\*(C`ev_timer\*(C'\fR's, they are not based on real time (or relative time) |
998 | but on wallclock time (absolute time). You can tell a periodic watcher |
1373 | but on wallclock time (absolute time). You can tell a periodic watcher |
999 | to trigger \*(L"at\*(R" some specific point in time. For example, if you tell a |
1374 | to trigger \*(L"at\*(R" some specific point in time. For example, if you tell a |
1000 | periodic watcher to trigger in 10 seconds (by specifiying e.g. \f(CW\*(C`ev_now () |
1375 | periodic watcher to trigger in 10 seconds (by specifiying e.g. \f(CW\*(C`ev_now () |
1001 | + 10.\*(C'\fR) and then reset your system clock to the last year, then it will |
1376 | + 10.\*(C'\fR) and then reset your system clock to the last year, then it will |
1002 | take a year to trigger the event (unlike an \f(CW\*(C`ev_timer\*(C'\fR, which would trigger |
1377 | take a year to trigger the event (unlike an \f(CW\*(C`ev_timer\*(C'\fR, which would trigger |
1003 | roughly 10 seconds later and of course not if you reset your system time |
1378 | roughly 10 seconds later). |
1004 | again). |
|
|
1005 | .PP |
1379 | .PP |
1006 | They can also be used to implement vastly more complex timers, such as |
1380 | They can also be used to implement vastly more complex timers, such as |
1007 | triggering an event on eahc midnight, local time. |
1381 | triggering an event on each midnight, local time or other, complicated, |
|
|
1382 | rules. |
1008 | .PP |
1383 | .PP |
1009 | As with timers, the callback is guarenteed to be invoked only when the |
1384 | As with timers, the callback is guarenteed to be invoked only when the |
1010 | time (\f(CW\*(C`at\*(C'\fR) has been passed, but if multiple periodic timers become ready |
1385 | time (\f(CW\*(C`at\*(C'\fR) has been passed, but if multiple periodic timers become ready |
1011 | during the same loop iteration then order of execution is undefined. |
1386 | during the same loop iteration then order of execution is undefined. |
|
|
1387 | .PP |
|
|
1388 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1389 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1012 | .IP "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" 4 |
1390 | .IP "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" 4 |
1013 | .IX Item "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" |
1391 | .IX Item "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" |
1014 | .PD 0 |
1392 | .PD 0 |
1015 | .IP "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" 4 |
1393 | .IP "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" 4 |
1016 | .IX Item "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" |
1394 | .IX Item "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" |
1017 | .PD |
1395 | .PD |
1018 | Lots of arguments, lets sort it out... There are basically three modes of |
1396 | Lots of arguments, lets sort it out... There are basically three modes of |
1019 | operation, and we will explain them from simplest to complex: |
1397 | operation, and we will explain them from simplest to complex: |
1020 | .RS 4 |
1398 | .RS 4 |
|
|
1399 | .IP "\(bu" 4 |
1021 | .IP "* absolute timer (interval = reschedule_cb = 0)" 4 |
1400 | absolute timer (at = time, interval = reschedule_cb = 0) |
1022 | .IX Item "absolute timer (interval = reschedule_cb = 0)" |
1401 | .Sp |
1023 | In this configuration the watcher triggers an event at the wallclock time |
1402 | In this configuration the watcher triggers an event at the wallclock time |
1024 | \&\f(CW\*(C`at\*(C'\fR and doesn't repeat. It will not adjust when a time jump occurs, |
1403 | \&\f(CW\*(C`at\*(C'\fR and doesn't repeat. It will not adjust when a time jump occurs, |
1025 | that is, if it is to be run at January 1st 2011 then it will run when the |
1404 | that is, if it is to be run at January 1st 2011 then it will run when the |
1026 | system time reaches or surpasses this time. |
1405 | system time reaches or surpasses this time. |
|
|
1406 | .IP "\(bu" 4 |
1027 | .IP "* non-repeating interval timer (interval > 0, reschedule_cb = 0)" 4 |
1407 | non-repeating interval timer (at = offset, interval > 0, reschedule_cb = 0) |
1028 | .IX Item "non-repeating interval timer (interval > 0, reschedule_cb = 0)" |
1408 | .Sp |
1029 | In this mode the watcher will always be scheduled to time out at the next |
1409 | In this mode the watcher will always be scheduled to time out at the next |
1030 | \&\f(CW\*(C`at + N * interval\*(C'\fR time (for some integer N) and then repeat, regardless |
1410 | \&\f(CW\*(C`at + N * interval\*(C'\fR time (for some integer N, which can also be negative) |
1031 | of any time jumps. |
1411 | and then repeat, regardless of any time jumps. |
1032 | .Sp |
1412 | .Sp |
1033 | This can be used to create timers that do not drift with respect to system |
1413 | This can be used to create timers that do not drift with respect to system |
1034 | time: |
1414 | time: |
1035 | .Sp |
1415 | .Sp |
1036 | .Vb 1 |
1416 | .Vb 1 |
… | |
… | |
1043 | by 3600. |
1423 | by 3600. |
1044 | .Sp |
1424 | .Sp |
1045 | Another way to think about it (for the mathematically inclined) is that |
1425 | Another way to think about it (for the mathematically inclined) is that |
1046 | \&\f(CW\*(C`ev_periodic\*(C'\fR will try to run the callback in this mode at the next possible |
1426 | \&\f(CW\*(C`ev_periodic\*(C'\fR will try to run the callback in this mode at the next possible |
1047 | time where \f(CW\*(C`time = at (mod interval)\*(C'\fR, regardless of any time jumps. |
1427 | time where \f(CW\*(C`time = at (mod interval)\*(C'\fR, regardless of any time jumps. |
1048 | .IP "* manual reschedule mode (reschedule_cb = callback)" 4 |
1428 | .Sp |
1049 | .IX Item "manual reschedule mode (reschedule_cb = callback)" |
1429 | For numerical stability it is preferable that the \f(CW\*(C`at\*(C'\fR value is near |
|
|
1430 | \&\f(CW\*(C`ev_now ()\*(C'\fR (the current time), but there is no range requirement for |
|
|
1431 | this value. |
|
|
1432 | .IP "\(bu" 4 |
|
|
1433 | manual reschedule mode (at and interval ignored, reschedule_cb = callback) |
|
|
1434 | .Sp |
1050 | In this mode the values for \f(CW\*(C`interval\*(C'\fR and \f(CW\*(C`at\*(C'\fR are both being |
1435 | In this mode the values for \f(CW\*(C`interval\*(C'\fR and \f(CW\*(C`at\*(C'\fR are both being |
1051 | ignored. Instead, each time the periodic watcher gets scheduled, the |
1436 | ignored. Instead, each time the periodic watcher gets scheduled, the |
1052 | reschedule callback will be called with the watcher as first, and the |
1437 | reschedule callback will be called with the watcher as first, and the |
1053 | current time as second argument. |
1438 | current time as second argument. |
1054 | .Sp |
1439 | .Sp |
1055 | \&\s-1NOTE:\s0 \fIThis callback \s-1MUST\s0 \s-1NOT\s0 stop or destroy any periodic watcher, |
1440 | \&\s-1NOTE:\s0 \fIThis callback \s-1MUST\s0 \s-1NOT\s0 stop or destroy any periodic watcher, |
1056 | ever, or make any event loop modifications\fR. If you need to stop it, |
1441 | ever, or make any event loop modifications\fR. If you need to stop it, |
1057 | return \f(CW\*(C`now + 1e30\*(C'\fR (or so, fudge fudge) and stop it afterwards (e.g. by |
1442 | return \f(CW\*(C`now + 1e30\*(C'\fR (or so, fudge fudge) and stop it afterwards (e.g. by |
1058 | starting a prepare watcher). |
1443 | starting an \f(CW\*(C`ev_prepare\*(C'\fR watcher, which is legal). |
1059 | .Sp |
1444 | .Sp |
1060 | Its prototype is \f(CW\*(C`ev_tstamp (*reschedule_cb)(struct ev_periodic *w, |
1445 | Its prototype is \f(CW\*(C`ev_tstamp (*reschedule_cb)(struct ev_periodic *w, |
1061 | ev_tstamp now)\*(C'\fR, e.g.: |
1446 | ev_tstamp now)\*(C'\fR, e.g.: |
1062 | .Sp |
1447 | .Sp |
1063 | .Vb 4 |
1448 | .Vb 4 |
… | |
… | |
1087 | .IX Item "ev_periodic_again (loop, ev_periodic *)" |
1472 | .IX Item "ev_periodic_again (loop, ev_periodic *)" |
1088 | Simply stops and restarts the periodic watcher again. This is only useful |
1473 | Simply stops and restarts the periodic watcher again. This is only useful |
1089 | when you changed some parameters or the reschedule callback would return |
1474 | when you changed some parameters or the reschedule callback would return |
1090 | a different time than the last time it was called (e.g. in a crond like |
1475 | a different time than the last time it was called (e.g. in a crond like |
1091 | program when the crontabs have changed). |
1476 | program when the crontabs have changed). |
|
|
1477 | .IP "ev_tstamp offset [read\-write]" 4 |
|
|
1478 | .IX Item "ev_tstamp offset [read-write]" |
|
|
1479 | When repeating, this contains the offset value, otherwise this is the |
|
|
1480 | absolute point in time (the \f(CW\*(C`at\*(C'\fR value passed to \f(CW\*(C`ev_periodic_set\*(C'\fR). |
|
|
1481 | .Sp |
|
|
1482 | Can be modified any time, but changes only take effect when the periodic |
|
|
1483 | timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called. |
|
|
1484 | .IP "ev_tstamp interval [read\-write]" 4 |
|
|
1485 | .IX Item "ev_tstamp interval [read-write]" |
|
|
1486 | The current interval value. Can be modified any time, but changes only |
|
|
1487 | take effect when the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being |
|
|
1488 | called. |
|
|
1489 | .IP "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read\-write]" 4 |
|
|
1490 | .IX Item "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write]" |
|
|
1491 | The current reschedule callback, or \f(CW0\fR, if this functionality is |
|
|
1492 | switched off. Can be changed any time, but changes only take effect when |
|
|
1493 | the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called. |
|
|
1494 | .IP "ev_tstamp at [read\-only]" 4 |
|
|
1495 | .IX Item "ev_tstamp at [read-only]" |
|
|
1496 | When active, contains the absolute time that the watcher is supposed to |
|
|
1497 | trigger next. |
1092 | .PP |
1498 | .PP |
|
|
1499 | \fIExamples\fR |
|
|
1500 | .IX Subsection "Examples" |
|
|
1501 | .PP |
1093 | Example: call a callback every hour, or, more precisely, whenever the |
1502 | Example: Call a callback every hour, or, more precisely, whenever the |
1094 | system clock is divisible by 3600. The callback invocation times have |
1503 | system clock is divisible by 3600. The callback invocation times have |
1095 | potentially a lot of jittering, but good long-term stability. |
1504 | potentially a lot of jittering, but good long-term stability. |
1096 | .PP |
1505 | .PP |
1097 | .Vb 5 |
1506 | .Vb 5 |
1098 | \& static void |
1507 | \& static void |
1099 | \& clock_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
1508 | \& clock_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
1100 | \& { |
1509 | \& { |
1101 | \& ... its now a full hour (UTC, or TAI or whatever your clock follows) |
1510 | \& ... its now a full hour (UTC, or TAI or whatever your clock follows) |
1102 | \& } |
1511 | \& } |
1103 | .Ve |
1512 | \& |
1104 | .PP |
|
|
1105 | .Vb 3 |
|
|
1106 | \& struct ev_periodic hourly_tick; |
1513 | \& struct ev_periodic hourly_tick; |
1107 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); |
1514 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); |
1108 | \& ev_periodic_start (loop, &hourly_tick); |
1515 | \& ev_periodic_start (loop, &hourly_tick); |
1109 | .Ve |
1516 | .Ve |
1110 | .PP |
1517 | .PP |
1111 | Example: the same as above, but use a reschedule callback to do it: |
1518 | Example: The same as above, but use a reschedule callback to do it: |
1112 | .PP |
1519 | .PP |
1113 | .Vb 1 |
1520 | .Vb 1 |
1114 | \& #include <math.h> |
1521 | \& #include <math.h> |
1115 | .Ve |
1522 | \& |
1116 | .PP |
|
|
1117 | .Vb 5 |
|
|
1118 | \& static ev_tstamp |
1523 | \& static ev_tstamp |
1119 | \& my_scheduler_cb (struct ev_periodic *w, ev_tstamp now) |
1524 | \& my_scheduler_cb (struct ev_periodic *w, ev_tstamp now) |
1120 | \& { |
1525 | \& { |
1121 | \& return fmod (now, 3600.) + 3600.; |
1526 | \& return fmod (now, 3600.) + 3600.; |
1122 | \& } |
1527 | \& } |
1123 | .Ve |
1528 | \& |
1124 | .PP |
|
|
1125 | .Vb 1 |
|
|
1126 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); |
1529 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); |
1127 | .Ve |
1530 | .Ve |
1128 | .PP |
1531 | .PP |
1129 | Example: call a callback every hour, starting now: |
1532 | Example: Call a callback every hour, starting now: |
1130 | .PP |
1533 | .PP |
1131 | .Vb 4 |
1534 | .Vb 4 |
1132 | \& struct ev_periodic hourly_tick; |
1535 | \& struct ev_periodic hourly_tick; |
1133 | \& ev_periodic_init (&hourly_tick, clock_cb, |
1536 | \& ev_periodic_init (&hourly_tick, clock_cb, |
1134 | \& fmod (ev_now (loop), 3600.), 3600., 0); |
1537 | \& fmod (ev_now (loop), 3600.), 3600., 0); |
1135 | \& ev_periodic_start (loop, &hourly_tick); |
1538 | \& ev_periodic_start (loop, &hourly_tick); |
1136 | .Ve |
1539 | .Ve |
1137 | .ie n .Sh """ev_signal"" \- signal me when a signal gets signalled" |
1540 | .ie n .Sh """ev_signal"" \- signal me when a signal gets signalled!" |
1138 | .el .Sh "\f(CWev_signal\fP \- signal me when a signal gets signalled" |
1541 | .el .Sh "\f(CWev_signal\fP \- signal me when a signal gets signalled!" |
1139 | .IX Subsection "ev_signal - signal me when a signal gets signalled" |
1542 | .IX Subsection "ev_signal - signal me when a signal gets signalled!" |
1140 | Signal watchers will trigger an event when the process receives a specific |
1543 | Signal watchers will trigger an event when the process receives a specific |
1141 | signal one or more times. Even though signals are very asynchronous, libev |
1544 | signal one or more times. Even though signals are very asynchronous, libev |
1142 | will try it's best to deliver signals synchronously, i.e. as part of the |
1545 | will try it's best to deliver signals synchronously, i.e. as part of the |
1143 | normal event processing, like any other event. |
1546 | normal event processing, like any other event. |
1144 | .PP |
1547 | .PP |
… | |
… | |
1146 | first watcher gets started will libev actually register a signal watcher |
1549 | first watcher gets started will libev actually register a signal watcher |
1147 | with the kernel (thus it coexists with your own signal handlers as long |
1550 | with the kernel (thus it coexists with your own signal handlers as long |
1148 | as you don't register any with libev). Similarly, when the last signal |
1551 | as you don't register any with libev). Similarly, when the last signal |
1149 | watcher for a signal is stopped libev will reset the signal handler to |
1552 | watcher for a signal is stopped libev will reset the signal handler to |
1150 | \&\s-1SIG_DFL\s0 (regardless of what it was set to before). |
1553 | \&\s-1SIG_DFL\s0 (regardless of what it was set to before). |
|
|
1554 | .PP |
|
|
1555 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1556 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1151 | .IP "ev_signal_init (ev_signal *, callback, int signum)" 4 |
1557 | .IP "ev_signal_init (ev_signal *, callback, int signum)" 4 |
1152 | .IX Item "ev_signal_init (ev_signal *, callback, int signum)" |
1558 | .IX Item "ev_signal_init (ev_signal *, callback, int signum)" |
1153 | .PD 0 |
1559 | .PD 0 |
1154 | .IP "ev_signal_set (ev_signal *, int signum)" 4 |
1560 | .IP "ev_signal_set (ev_signal *, int signum)" 4 |
1155 | .IX Item "ev_signal_set (ev_signal *, int signum)" |
1561 | .IX Item "ev_signal_set (ev_signal *, int signum)" |
1156 | .PD |
1562 | .PD |
1157 | Configures the watcher to trigger on the given signal number (usually one |
1563 | Configures the watcher to trigger on the given signal number (usually one |
1158 | of the \f(CW\*(C`SIGxxx\*(C'\fR constants). |
1564 | of the \f(CW\*(C`SIGxxx\*(C'\fR constants). |
|
|
1565 | .IP "int signum [read\-only]" 4 |
|
|
1566 | .IX Item "int signum [read-only]" |
|
|
1567 | The signal the watcher watches out for. |
1159 | .ie n .Sh """ev_child"" \- wait for pid status changes" |
1568 | .ie n .Sh """ev_child"" \- watch out for process status changes" |
1160 | .el .Sh "\f(CWev_child\fP \- wait for pid status changes" |
1569 | .el .Sh "\f(CWev_child\fP \- watch out for process status changes" |
1161 | .IX Subsection "ev_child - wait for pid status changes" |
1570 | .IX Subsection "ev_child - watch out for process status changes" |
1162 | Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to |
1571 | Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to |
1163 | some child status changes (most typically when a child of yours dies). |
1572 | some child status changes (most typically when a child of yours dies). |
|
|
1573 | .PP |
|
|
1574 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1575 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1164 | .IP "ev_child_init (ev_child *, callback, int pid)" 4 |
1576 | .IP "ev_child_init (ev_child *, callback, int pid, int trace)" 4 |
1165 | .IX Item "ev_child_init (ev_child *, callback, int pid)" |
1577 | .IX Item "ev_child_init (ev_child *, callback, int pid, int trace)" |
1166 | .PD 0 |
1578 | .PD 0 |
1167 | .IP "ev_child_set (ev_child *, int pid)" 4 |
1579 | .IP "ev_child_set (ev_child *, int pid, int trace)" 4 |
1168 | .IX Item "ev_child_set (ev_child *, int pid)" |
1580 | .IX Item "ev_child_set (ev_child *, int pid, int trace)" |
1169 | .PD |
1581 | .PD |
1170 | Configures the watcher to wait for status changes of process \f(CW\*(C`pid\*(C'\fR (or |
1582 | Configures the watcher to wait for status changes of process \f(CW\*(C`pid\*(C'\fR (or |
1171 | \&\fIany\fR process if \f(CW\*(C`pid\*(C'\fR is specified as \f(CW0\fR). The callback can look |
1583 | \&\fIany\fR process if \f(CW\*(C`pid\*(C'\fR is specified as \f(CW0\fR). The callback can look |
1172 | at the \f(CW\*(C`rstatus\*(C'\fR member of the \f(CW\*(C`ev_child\*(C'\fR watcher structure to see |
1584 | at the \f(CW\*(C`rstatus\*(C'\fR member of the \f(CW\*(C`ev_child\*(C'\fR watcher structure to see |
1173 | the status word (use the macros from \f(CW\*(C`sys/wait.h\*(C'\fR and see your systems |
1585 | the status word (use the macros from \f(CW\*(C`sys/wait.h\*(C'\fR and see your systems |
1174 | \&\f(CW\*(C`waitpid\*(C'\fR documentation). The \f(CW\*(C`rpid\*(C'\fR member contains the pid of the |
1586 | \&\f(CW\*(C`waitpid\*(C'\fR documentation). The \f(CW\*(C`rpid\*(C'\fR member contains the pid of the |
1175 | process causing the status change. |
1587 | process causing the status change. \f(CW\*(C`trace\*(C'\fR must be either \f(CW0\fR (only |
|
|
1588 | activate the watcher when the process terminates) or \f(CW1\fR (additionally |
|
|
1589 | activate the watcher when the process is stopped or continued). |
|
|
1590 | .IP "int pid [read\-only]" 4 |
|
|
1591 | .IX Item "int pid [read-only]" |
|
|
1592 | The process id this watcher watches out for, or \f(CW0\fR, meaning any process id. |
|
|
1593 | .IP "int rpid [read\-write]" 4 |
|
|
1594 | .IX Item "int rpid [read-write]" |
|
|
1595 | The process id that detected a status change. |
|
|
1596 | .IP "int rstatus [read\-write]" 4 |
|
|
1597 | .IX Item "int rstatus [read-write]" |
|
|
1598 | The process exit/trace status caused by \f(CW\*(C`rpid\*(C'\fR (see your systems |
|
|
1599 | \&\f(CW\*(C`waitpid\*(C'\fR and \f(CW\*(C`sys/wait.h\*(C'\fR documentation for details). |
1176 | .PP |
1600 | .PP |
|
|
1601 | \fIExamples\fR |
|
|
1602 | .IX Subsection "Examples" |
|
|
1603 | .PP |
1177 | Example: try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0. |
1604 | Example: Try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0. |
1178 | .PP |
1605 | .PP |
1179 | .Vb 5 |
1606 | .Vb 5 |
1180 | \& static void |
1607 | \& static void |
1181 | \& sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
1608 | \& sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
1182 | \& { |
1609 | \& { |
1183 | \& ev_unloop (loop, EVUNLOOP_ALL); |
1610 | \& ev_unloop (loop, EVUNLOOP_ALL); |
1184 | \& } |
1611 | \& } |
1185 | .Ve |
1612 | \& |
1186 | .PP |
|
|
1187 | .Vb 3 |
|
|
1188 | \& struct ev_signal signal_watcher; |
1613 | \& struct ev_signal signal_watcher; |
1189 | \& ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
1614 | \& ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
1190 | \& ev_signal_start (loop, &sigint_cb); |
1615 | \& ev_signal_start (loop, &sigint_cb); |
1191 | .Ve |
1616 | .Ve |
|
|
1617 | .ie n .Sh """ev_stat"" \- did the file attributes just change?" |
|
|
1618 | .el .Sh "\f(CWev_stat\fP \- did the file attributes just change?" |
|
|
1619 | .IX Subsection "ev_stat - did the file attributes just change?" |
|
|
1620 | This watches a filesystem path for attribute changes. That is, it calls |
|
|
1621 | \&\f(CW\*(C`stat\*(C'\fR regularly (or when the \s-1OS\s0 says it changed) and sees if it changed |
|
|
1622 | compared to the last time, invoking the callback if it did. |
|
|
1623 | .PP |
|
|
1624 | The path does not need to exist: changing from \*(L"path exists\*(R" to \*(L"path does |
|
|
1625 | not exist\*(R" is a status change like any other. The condition \*(L"path does |
|
|
1626 | not exist\*(R" is signified by the \f(CW\*(C`st_nlink\*(C'\fR field being zero (which is |
|
|
1627 | otherwise always forced to be at least one) and all the other fields of |
|
|
1628 | the stat buffer having unspecified contents. |
|
|
1629 | .PP |
|
|
1630 | The path \fIshould\fR be absolute and \fImust not\fR end in a slash. If it is |
|
|
1631 | relative and your working directory changes, the behaviour is undefined. |
|
|
1632 | .PP |
|
|
1633 | Since there is no standard to do this, the portable implementation simply |
|
|
1634 | calls \f(CW\*(C`stat (2)\*(C'\fR regularly on the path to see if it changed somehow. You |
|
|
1635 | can specify a recommended polling interval for this case. If you specify |
|
|
1636 | a polling interval of \f(CW0\fR (highly recommended!) then a \fIsuitable, |
|
|
1637 | unspecified default\fR value will be used (which you can expect to be around |
|
|
1638 | five seconds, although this might change dynamically). Libev will also |
|
|
1639 | impose a minimum interval which is currently around \f(CW0.1\fR, but thats |
|
|
1640 | usually overkill. |
|
|
1641 | .PP |
|
|
1642 | This watcher type is not meant for massive numbers of stat watchers, |
|
|
1643 | as even with OS-supported change notifications, this can be |
|
|
1644 | resource-intensive. |
|
|
1645 | .PP |
|
|
1646 | At the time of this writing, only the Linux inotify interface is |
|
|
1647 | implemented (implementing kqueue support is left as an exercise for the |
|
|
1648 | reader). Inotify will be used to give hints only and should not change the |
|
|
1649 | semantics of \f(CW\*(C`ev_stat\*(C'\fR watchers, which means that libev sometimes needs |
|
|
1650 | to fall back to regular polling again even with inotify, but changes are |
|
|
1651 | usually detected immediately, and if the file exists there will be no |
|
|
1652 | polling. |
|
|
1653 | .PP |
|
|
1654 | \fIInotify\fR |
|
|
1655 | .IX Subsection "Inotify" |
|
|
1656 | .PP |
|
|
1657 | When \f(CW\*(C`inotify (7)\*(C'\fR support has been compiled into libev (generally only |
|
|
1658 | available on Linux) and present at runtime, it will be used to speed up |
|
|
1659 | change detection where possible. The inotify descriptor will be created lazily |
|
|
1660 | when the first \f(CW\*(C`ev_stat\*(C'\fR watcher is being started. |
|
|
1661 | .PP |
|
|
1662 | Inotify presense does not change the semantics of \f(CW\*(C`ev_stat\*(C'\fR watchers |
|
|
1663 | except that changes might be detected earlier, and in some cases, to avoid |
|
|
1664 | making regular \f(CW\*(C`stat\*(C'\fR calls. Even in the presense of inotify support |
|
|
1665 | there are many cases where libev has to resort to regular \f(CW\*(C`stat\*(C'\fR polling. |
|
|
1666 | .PP |
|
|
1667 | (There is no support for kqueue, as apparently it cannot be used to |
|
|
1668 | implement this functionality, due to the requirement of having a file |
|
|
1669 | descriptor open on the object at all times). |
|
|
1670 | .PP |
|
|
1671 | \fIThe special problem of stat time resolution\fR |
|
|
1672 | .IX Subsection "The special problem of stat time resolution" |
|
|
1673 | .PP |
|
|
1674 | The \f(CW\*(C`stat ()\*(C'\fR syscall only supports full-second resolution portably, and |
|
|
1675 | even on systems where the resolution is higher, many filesystems still |
|
|
1676 | only support whole seconds. |
|
|
1677 | .PP |
|
|
1678 | That means that, if the time is the only thing that changes, you might |
|
|
1679 | miss updates: on the first update, \f(CW\*(C`ev_stat\*(C'\fR detects a change and calls |
|
|
1680 | your callback, which does something. When there is another update within |
|
|
1681 | the same second, \f(CW\*(C`ev_stat\*(C'\fR will be unable to detect it. |
|
|
1682 | .PP |
|
|
1683 | The solution to this is to delay acting on a change for a second (or till |
|
|
1684 | the next second boundary), using a roughly one-second delay \f(CW\*(C`ev_timer\*(C'\fR |
|
|
1685 | (\f(CW\*(C`ev_timer_set (w, 0., 1.01); ev_timer_again (loop, w)\*(C'\fR). The \f(CW.01\fR |
|
|
1686 | is added to work around small timing inconsistencies of some operating |
|
|
1687 | systems. |
|
|
1688 | .PP |
|
|
1689 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1690 | .IX Subsection "Watcher-Specific Functions and Data Members" |
|
|
1691 | .IP "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" 4 |
|
|
1692 | .IX Item "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" |
|
|
1693 | .PD 0 |
|
|
1694 | .IP "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" 4 |
|
|
1695 | .IX Item "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" |
|
|
1696 | .PD |
|
|
1697 | Configures the watcher to wait for status changes of the given |
|
|
1698 | \&\f(CW\*(C`path\*(C'\fR. The \f(CW\*(C`interval\*(C'\fR is a hint on how quickly a change is expected to |
|
|
1699 | be detected and should normally be specified as \f(CW0\fR to let libev choose |
|
|
1700 | a suitable value. The memory pointed to by \f(CW\*(C`path\*(C'\fR must point to the same |
|
|
1701 | path for as long as the watcher is active. |
|
|
1702 | .Sp |
|
|
1703 | The callback will be receive \f(CW\*(C`EV_STAT\*(C'\fR when a change was detected, |
|
|
1704 | relative to the attributes at the time the watcher was started (or the |
|
|
1705 | last change was detected). |
|
|
1706 | .IP "ev_stat_stat (ev_stat *)" 4 |
|
|
1707 | .IX Item "ev_stat_stat (ev_stat *)" |
|
|
1708 | Updates the stat buffer immediately with new values. If you change the |
|
|
1709 | watched path in your callback, you could call this fucntion to avoid |
|
|
1710 | detecting this change (while introducing a race condition). Can also be |
|
|
1711 | useful simply to find out the new values. |
|
|
1712 | .IP "ev_statdata attr [read\-only]" 4 |
|
|
1713 | .IX Item "ev_statdata attr [read-only]" |
|
|
1714 | The most-recently detected attributes of the file. Although the type is of |
|
|
1715 | \&\f(CW\*(C`ev_statdata\*(C'\fR, this is usually the (or one of the) \f(CW\*(C`struct stat\*(C'\fR types |
|
|
1716 | suitable for your system. If the \f(CW\*(C`st_nlink\*(C'\fR member is \f(CW0\fR, then there |
|
|
1717 | was some error while \f(CW\*(C`stat\*(C'\fRing the file. |
|
|
1718 | .IP "ev_statdata prev [read\-only]" 4 |
|
|
1719 | .IX Item "ev_statdata prev [read-only]" |
|
|
1720 | The previous attributes of the file. The callback gets invoked whenever |
|
|
1721 | \&\f(CW\*(C`prev\*(C'\fR != \f(CW\*(C`attr\*(C'\fR. |
|
|
1722 | .IP "ev_tstamp interval [read\-only]" 4 |
|
|
1723 | .IX Item "ev_tstamp interval [read-only]" |
|
|
1724 | The specified interval. |
|
|
1725 | .IP "const char *path [read\-only]" 4 |
|
|
1726 | .IX Item "const char *path [read-only]" |
|
|
1727 | The filesystem path that is being watched. |
|
|
1728 | .PP |
|
|
1729 | \fIExamples\fR |
|
|
1730 | .IX Subsection "Examples" |
|
|
1731 | .PP |
|
|
1732 | Example: Watch \f(CW\*(C`/etc/passwd\*(C'\fR for attribute changes. |
|
|
1733 | .PP |
|
|
1734 | .Vb 10 |
|
|
1735 | \& static void |
|
|
1736 | \& passwd_cb (struct ev_loop *loop, ev_stat *w, int revents) |
|
|
1737 | \& { |
|
|
1738 | \& /* /etc/passwd changed in some way */ |
|
|
1739 | \& if (w\->attr.st_nlink) |
|
|
1740 | \& { |
|
|
1741 | \& printf ("passwd current size %ld\en", (long)w\->attr.st_size); |
|
|
1742 | \& printf ("passwd current atime %ld\en", (long)w\->attr.st_mtime); |
|
|
1743 | \& printf ("passwd current mtime %ld\en", (long)w\->attr.st_mtime); |
|
|
1744 | \& } |
|
|
1745 | \& else |
|
|
1746 | \& /* you shalt not abuse printf for puts */ |
|
|
1747 | \& puts ("wow, /etc/passwd is not there, expect problems. " |
|
|
1748 | \& "if this is windows, they already arrived\en"); |
|
|
1749 | \& } |
|
|
1750 | \& |
|
|
1751 | \& ... |
|
|
1752 | \& ev_stat passwd; |
|
|
1753 | \& |
|
|
1754 | \& ev_stat_init (&passwd, passwd_cb, "/etc/passwd", 0.); |
|
|
1755 | \& ev_stat_start (loop, &passwd); |
|
|
1756 | .Ve |
|
|
1757 | .PP |
|
|
1758 | Example: Like above, but additionally use a one-second delay so we do not |
|
|
1759 | miss updates (however, frequent updates will delay processing, too, so |
|
|
1760 | one might do the work both on \f(CW\*(C`ev_stat\*(C'\fR callback invocation \fIand\fR on |
|
|
1761 | \&\f(CW\*(C`ev_timer\*(C'\fR callback invocation). |
|
|
1762 | .PP |
|
|
1763 | .Vb 2 |
|
|
1764 | \& static ev_stat passwd; |
|
|
1765 | \& static ev_timer timer; |
|
|
1766 | \& |
|
|
1767 | \& static void |
|
|
1768 | \& timer_cb (EV_P_ ev_timer *w, int revents) |
|
|
1769 | \& { |
|
|
1770 | \& ev_timer_stop (EV_A_ w); |
|
|
1771 | \& |
|
|
1772 | \& /* now it\*(Aqs one second after the most recent passwd change */ |
|
|
1773 | \& } |
|
|
1774 | \& |
|
|
1775 | \& static void |
|
|
1776 | \& stat_cb (EV_P_ ev_stat *w, int revents) |
|
|
1777 | \& { |
|
|
1778 | \& /* reset the one\-second timer */ |
|
|
1779 | \& ev_timer_again (EV_A_ &timer); |
|
|
1780 | \& } |
|
|
1781 | \& |
|
|
1782 | \& ... |
|
|
1783 | \& ev_stat_init (&passwd, stat_cb, "/etc/passwd", 0.); |
|
|
1784 | \& ev_stat_start (loop, &passwd); |
|
|
1785 | \& ev_timer_init (&timer, timer_cb, 0., 1.01); |
|
|
1786 | .Ve |
1192 | .ie n .Sh """ev_idle"" \- when you've got nothing better to do" |
1787 | .ie n .Sh """ev_idle"" \- when you've got nothing better to do..." |
1193 | .el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do" |
1788 | .el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do..." |
1194 | .IX Subsection "ev_idle - when you've got nothing better to do" |
1789 | .IX Subsection "ev_idle - when you've got nothing better to do..." |
1195 | Idle watchers trigger events when there are no other events are pending |
1790 | Idle watchers trigger events when no other events of the same or higher |
1196 | (prepare, check and other idle watchers do not count). That is, as long |
1791 | priority are pending (prepare, check and other idle watchers do not |
1197 | as your process is busy handling sockets or timeouts (or even signals, |
1792 | count). |
1198 | imagine) it will not be triggered. But when your process is idle all idle |
1793 | .PP |
1199 | watchers are being called again and again, once per event loop iteration \- |
1794 | That is, as long as your process is busy handling sockets or timeouts |
|
|
1795 | (or even signals, imagine) of the same or higher priority it will not be |
|
|
1796 | triggered. But when your process is idle (or only lower-priority watchers |
|
|
1797 | are pending), the idle watchers are being called once per event loop |
1200 | until stopped, that is, or your process receives more events and becomes |
1798 | iteration \- until stopped, that is, or your process receives more events |
1201 | busy. |
1799 | and becomes busy again with higher priority stuff. |
1202 | .PP |
1800 | .PP |
1203 | The most noteworthy effect is that as long as any idle watchers are |
1801 | The most noteworthy effect is that as long as any idle watchers are |
1204 | active, the process will not block when waiting for new events. |
1802 | active, the process will not block when waiting for new events. |
1205 | .PP |
1803 | .PP |
1206 | Apart from keeping your process non-blocking (which is a useful |
1804 | Apart from keeping your process non-blocking (which is a useful |
1207 | effect on its own sometimes), idle watchers are a good place to do |
1805 | effect on its own sometimes), idle watchers are a good place to do |
1208 | \&\*(L"pseudo\-background processing\*(R", or delay processing stuff to after the |
1806 | \&\*(L"pseudo-background processing\*(R", or delay processing stuff to after the |
1209 | event loop has handled all outstanding events. |
1807 | event loop has handled all outstanding events. |
|
|
1808 | .PP |
|
|
1809 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1810 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1210 | .IP "ev_idle_init (ev_signal *, callback)" 4 |
1811 | .IP "ev_idle_init (ev_signal *, callback)" 4 |
1211 | .IX Item "ev_idle_init (ev_signal *, callback)" |
1812 | .IX Item "ev_idle_init (ev_signal *, callback)" |
1212 | Initialises and configures the idle watcher \- it has no parameters of any |
1813 | Initialises and configures the idle watcher \- it has no parameters of any |
1213 | kind. There is a \f(CW\*(C`ev_idle_set\*(C'\fR macro, but using it is utterly pointless, |
1814 | kind. There is a \f(CW\*(C`ev_idle_set\*(C'\fR macro, but using it is utterly pointless, |
1214 | believe me. |
1815 | believe me. |
1215 | .PP |
1816 | .PP |
|
|
1817 | \fIExamples\fR |
|
|
1818 | .IX Subsection "Examples" |
|
|
1819 | .PP |
1216 | Example: dynamically allocate an \f(CW\*(C`ev_idle\*(C'\fR, start it, and in the |
1820 | Example: Dynamically allocate an \f(CW\*(C`ev_idle\*(C'\fR watcher, start it, and in the |
1217 | callback, free it. Alos, use no error checking, as usual. |
1821 | callback, free it. Also, use no error checking, as usual. |
1218 | .PP |
1822 | .PP |
1219 | .Vb 7 |
1823 | .Vb 7 |
1220 | \& static void |
1824 | \& static void |
1221 | \& idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
1825 | \& idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
1222 | \& { |
1826 | \& { |
1223 | \& free (w); |
1827 | \& free (w); |
1224 | \& // now do something you wanted to do when the program has |
1828 | \& // now do something you wanted to do when the program has |
1225 | \& // no longer asnything immediate to do. |
1829 | \& // no longer anything immediate to do. |
1226 | \& } |
1830 | \& } |
1227 | .Ve |
1831 | \& |
1228 | .PP |
|
|
1229 | .Vb 3 |
|
|
1230 | \& struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle)); |
1832 | \& struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle)); |
1231 | \& ev_idle_init (idle_watcher, idle_cb); |
1833 | \& ev_idle_init (idle_watcher, idle_cb); |
1232 | \& ev_idle_start (loop, idle_cb); |
1834 | \& ev_idle_start (loop, idle_cb); |
1233 | .Ve |
1835 | .Ve |
1234 | .ie n .Sh """ev_prepare""\fP and \f(CW""ev_check"" \- customise your event loop" |
1836 | .ie n .Sh """ev_prepare""\fP and \f(CW""ev_check"" \- customise your event loop!" |
1235 | .el .Sh "\f(CWev_prepare\fP and \f(CWev_check\fP \- customise your event loop" |
1837 | .el .Sh "\f(CWev_prepare\fP and \f(CWev_check\fP \- customise your event loop!" |
1236 | .IX Subsection "ev_prepare and ev_check - customise your event loop" |
1838 | .IX Subsection "ev_prepare and ev_check - customise your event loop!" |
1237 | Prepare and check watchers are usually (but not always) used in tandem: |
1839 | Prepare and check watchers are usually (but not always) used in tandem: |
1238 | prepare watchers get invoked before the process blocks and check watchers |
1840 | prepare watchers get invoked before the process blocks and check watchers |
1239 | afterwards. |
1841 | afterwards. |
1240 | .PP |
1842 | .PP |
|
|
1843 | You \fImust not\fR call \f(CW\*(C`ev_loop\*(C'\fR or similar functions that enter |
|
|
1844 | the current event loop from either \f(CW\*(C`ev_prepare\*(C'\fR or \f(CW\*(C`ev_check\*(C'\fR |
|
|
1845 | watchers. Other loops than the current one are fine, however. The |
|
|
1846 | rationale behind this is that you do not need to check for recursion in |
|
|
1847 | those watchers, i.e. the sequence will always be \f(CW\*(C`ev_prepare\*(C'\fR, blocking, |
|
|
1848 | \&\f(CW\*(C`ev_check\*(C'\fR so if you have one watcher of each kind they will always be |
|
|
1849 | called in pairs bracketing the blocking call. |
|
|
1850 | .PP |
1241 | Their main purpose is to integrate other event mechanisms into libev and |
1851 | Their main purpose is to integrate other event mechanisms into libev and |
1242 | their use is somewhat advanced. This could be used, for example, to track |
1852 | their use is somewhat advanced. This could be used, for example, to track |
1243 | variable changes, implement your own watchers, integrate net-snmp or a |
1853 | variable changes, implement your own watchers, integrate net-snmp or a |
1244 | coroutine library and lots more. |
1854 | coroutine library and lots more. They are also occasionally useful if |
|
|
1855 | you cache some data and want to flush it before blocking (for example, |
|
|
1856 | in X programs you might want to do an \f(CW\*(C`XFlush ()\*(C'\fR in an \f(CW\*(C`ev_prepare\*(C'\fR |
|
|
1857 | watcher). |
1245 | .PP |
1858 | .PP |
1246 | This is done by examining in each prepare call which file descriptors need |
1859 | This is done by examining in each prepare call which file descriptors need |
1247 | to be watched by the other library, registering \f(CW\*(C`ev_io\*(C'\fR watchers for |
1860 | to be watched by the other library, registering \f(CW\*(C`ev_io\*(C'\fR watchers for |
1248 | them and starting an \f(CW\*(C`ev_timer\*(C'\fR watcher for any timeouts (many libraries |
1861 | them and starting an \f(CW\*(C`ev_timer\*(C'\fR watcher for any timeouts (many libraries |
1249 | provide just this functionality). Then, in the check watcher you check for |
1862 | provide just this functionality). Then, in the check watcher you check for |
… | |
… | |
1258 | are ready to run (it's actually more complicated: it only runs coroutines |
1871 | are ready to run (it's actually more complicated: it only runs coroutines |
1259 | with priority higher than or equal to the event loop and one coroutine |
1872 | with priority higher than or equal to the event loop and one coroutine |
1260 | of lower priority, but only once, using idle watchers to keep the event |
1873 | of lower priority, but only once, using idle watchers to keep the event |
1261 | loop from blocking if lower-priority coroutines are active, thus mapping |
1874 | loop from blocking if lower-priority coroutines are active, thus mapping |
1262 | low-priority coroutines to idle/background tasks). |
1875 | low-priority coroutines to idle/background tasks). |
|
|
1876 | .PP |
|
|
1877 | It is recommended to give \f(CW\*(C`ev_check\*(C'\fR watchers highest (\f(CW\*(C`EV_MAXPRI\*(C'\fR) |
|
|
1878 | priority, to ensure that they are being run before any other watchers |
|
|
1879 | after the poll. Also, \f(CW\*(C`ev_check\*(C'\fR watchers (and \f(CW\*(C`ev_prepare\*(C'\fR watchers, |
|
|
1880 | too) should not activate (\*(L"feed\*(R") events into libev. While libev fully |
|
|
1881 | supports this, they will be called before other \f(CW\*(C`ev_check\*(C'\fR watchers |
|
|
1882 | did their job. As \f(CW\*(C`ev_check\*(C'\fR watchers are often used to embed other |
|
|
1883 | (non-libev) event loops those other event loops might be in an unusable |
|
|
1884 | state until their \f(CW\*(C`ev_check\*(C'\fR watcher ran (always remind yourself to |
|
|
1885 | coexist peacefully with others). |
|
|
1886 | .PP |
|
|
1887 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1888 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1263 | .IP "ev_prepare_init (ev_prepare *, callback)" 4 |
1889 | .IP "ev_prepare_init (ev_prepare *, callback)" 4 |
1264 | .IX Item "ev_prepare_init (ev_prepare *, callback)" |
1890 | .IX Item "ev_prepare_init (ev_prepare *, callback)" |
1265 | .PD 0 |
1891 | .PD 0 |
1266 | .IP "ev_check_init (ev_check *, callback)" 4 |
1892 | .IP "ev_check_init (ev_check *, callback)" 4 |
1267 | .IX Item "ev_check_init (ev_check *, callback)" |
1893 | .IX Item "ev_check_init (ev_check *, callback)" |
1268 | .PD |
1894 | .PD |
1269 | Initialises and configures the prepare or check watcher \- they have no |
1895 | Initialises and configures the prepare or check watcher \- they have no |
1270 | parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR |
1896 | parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR |
1271 | macros, but using them is utterly, utterly and completely pointless. |
1897 | macros, but using them is utterly, utterly and completely pointless. |
1272 | .PP |
1898 | .PP |
1273 | Example: *TODO*. |
1899 | \fIExamples\fR |
|
|
1900 | .IX Subsection "Examples" |
|
|
1901 | .PP |
|
|
1902 | There are a number of principal ways to embed other event loops or modules |
|
|
1903 | into libev. Here are some ideas on how to include libadns into libev |
|
|
1904 | (there is a Perl module named \f(CW\*(C`EV::ADNS\*(C'\fR that does this, which you could |
|
|
1905 | use for an actually working example. Another Perl module named \f(CW\*(C`EV::Glib\*(C'\fR |
|
|
1906 | embeds a Glib main context into libev, and finally, \f(CW\*(C`Glib::EV\*(C'\fR embeds \s-1EV\s0 |
|
|
1907 | into the Glib event loop). |
|
|
1908 | .PP |
|
|
1909 | Method 1: Add \s-1IO\s0 watchers and a timeout watcher in a prepare handler, |
|
|
1910 | and in a check watcher, destroy them and call into libadns. What follows |
|
|
1911 | is pseudo-code only of course. This requires you to either use a low |
|
|
1912 | priority for the check watcher or use \f(CW\*(C`ev_clear_pending\*(C'\fR explicitly, as |
|
|
1913 | the callbacks for the IO/timeout watchers might not have been called yet. |
|
|
1914 | .PP |
|
|
1915 | .Vb 2 |
|
|
1916 | \& static ev_io iow [nfd]; |
|
|
1917 | \& static ev_timer tw; |
|
|
1918 | \& |
|
|
1919 | \& static void |
|
|
1920 | \& io_cb (ev_loop *loop, ev_io *w, int revents) |
|
|
1921 | \& { |
|
|
1922 | \& } |
|
|
1923 | \& |
|
|
1924 | \& // create io watchers for each fd and a timer before blocking |
|
|
1925 | \& static void |
|
|
1926 | \& adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
|
|
1927 | \& { |
|
|
1928 | \& int timeout = 3600000; |
|
|
1929 | \& struct pollfd fds [nfd]; |
|
|
1930 | \& // actual code will need to loop here and realloc etc. |
|
|
1931 | \& adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
|
|
1932 | \& |
|
|
1933 | \& /* the callback is illegal, but won\*(Aqt be called as we stop during check */ |
|
|
1934 | \& ev_timer_init (&tw, 0, timeout * 1e\-3); |
|
|
1935 | \& ev_timer_start (loop, &tw); |
|
|
1936 | \& |
|
|
1937 | \& // create one ev_io per pollfd |
|
|
1938 | \& for (int i = 0; i < nfd; ++i) |
|
|
1939 | \& { |
|
|
1940 | \& ev_io_init (iow + i, io_cb, fds [i].fd, |
|
|
1941 | \& ((fds [i].events & POLLIN ? EV_READ : 0) |
|
|
1942 | \& | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
|
|
1943 | \& |
|
|
1944 | \& fds [i].revents = 0; |
|
|
1945 | \& ev_io_start (loop, iow + i); |
|
|
1946 | \& } |
|
|
1947 | \& } |
|
|
1948 | \& |
|
|
1949 | \& // stop all watchers after blocking |
|
|
1950 | \& static void |
|
|
1951 | \& adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
|
|
1952 | \& { |
|
|
1953 | \& ev_timer_stop (loop, &tw); |
|
|
1954 | \& |
|
|
1955 | \& for (int i = 0; i < nfd; ++i) |
|
|
1956 | \& { |
|
|
1957 | \& // set the relevant poll flags |
|
|
1958 | \& // could also call adns_processreadable etc. here |
|
|
1959 | \& struct pollfd *fd = fds + i; |
|
|
1960 | \& int revents = ev_clear_pending (iow + i); |
|
|
1961 | \& if (revents & EV_READ ) fd\->revents |= fd\->events & POLLIN; |
|
|
1962 | \& if (revents & EV_WRITE) fd\->revents |= fd\->events & POLLOUT; |
|
|
1963 | \& |
|
|
1964 | \& // now stop the watcher |
|
|
1965 | \& ev_io_stop (loop, iow + i); |
|
|
1966 | \& } |
|
|
1967 | \& |
|
|
1968 | \& adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
|
|
1969 | \& } |
|
|
1970 | .Ve |
|
|
1971 | .PP |
|
|
1972 | Method 2: This would be just like method 1, but you run \f(CW\*(C`adns_afterpoll\*(C'\fR |
|
|
1973 | in the prepare watcher and would dispose of the check watcher. |
|
|
1974 | .PP |
|
|
1975 | Method 3: If the module to be embedded supports explicit event |
|
|
1976 | notification (adns does), you can also make use of the actual watcher |
|
|
1977 | callbacks, and only destroy/create the watchers in the prepare watcher. |
|
|
1978 | .PP |
|
|
1979 | .Vb 5 |
|
|
1980 | \& static void |
|
|
1981 | \& timer_cb (EV_P_ ev_timer *w, int revents) |
|
|
1982 | \& { |
|
|
1983 | \& adns_state ads = (adns_state)w\->data; |
|
|
1984 | \& update_now (EV_A); |
|
|
1985 | \& |
|
|
1986 | \& adns_processtimeouts (ads, &tv_now); |
|
|
1987 | \& } |
|
|
1988 | \& |
|
|
1989 | \& static void |
|
|
1990 | \& io_cb (EV_P_ ev_io *w, int revents) |
|
|
1991 | \& { |
|
|
1992 | \& adns_state ads = (adns_state)w\->data; |
|
|
1993 | \& update_now (EV_A); |
|
|
1994 | \& |
|
|
1995 | \& if (revents & EV_READ ) adns_processreadable (ads, w\->fd, &tv_now); |
|
|
1996 | \& if (revents & EV_WRITE) adns_processwriteable (ads, w\->fd, &tv_now); |
|
|
1997 | \& } |
|
|
1998 | \& |
|
|
1999 | \& // do not ever call adns_afterpoll |
|
|
2000 | .Ve |
|
|
2001 | .PP |
|
|
2002 | Method 4: Do not use a prepare or check watcher because the module you |
|
|
2003 | want to embed is too inflexible to support it. Instead, youc na override |
|
|
2004 | their poll function. The drawback with this solution is that the main |
|
|
2005 | loop is now no longer controllable by \s-1EV\s0. The \f(CW\*(C`Glib::EV\*(C'\fR module does |
|
|
2006 | this. |
|
|
2007 | .PP |
|
|
2008 | .Vb 4 |
|
|
2009 | \& static gint |
|
|
2010 | \& event_poll_func (GPollFD *fds, guint nfds, gint timeout) |
|
|
2011 | \& { |
|
|
2012 | \& int got_events = 0; |
|
|
2013 | \& |
|
|
2014 | \& for (n = 0; n < nfds; ++n) |
|
|
2015 | \& // create/start io watcher that sets the relevant bits in fds[n] and increment got_events |
|
|
2016 | \& |
|
|
2017 | \& if (timeout >= 0) |
|
|
2018 | \& // create/start timer |
|
|
2019 | \& |
|
|
2020 | \& // poll |
|
|
2021 | \& ev_loop (EV_A_ 0); |
|
|
2022 | \& |
|
|
2023 | \& // stop timer again |
|
|
2024 | \& if (timeout >= 0) |
|
|
2025 | \& ev_timer_stop (EV_A_ &to); |
|
|
2026 | \& |
|
|
2027 | \& // stop io watchers again \- their callbacks should have set |
|
|
2028 | \& for (n = 0; n < nfds; ++n) |
|
|
2029 | \& ev_io_stop (EV_A_ iow [n]); |
|
|
2030 | \& |
|
|
2031 | \& return got_events; |
|
|
2032 | \& } |
|
|
2033 | .Ve |
1274 | .ie n .Sh """ev_embed"" \- when one backend isn't enough" |
2034 | .ie n .Sh """ev_embed"" \- when one backend isn't enough..." |
1275 | .el .Sh "\f(CWev_embed\fP \- when one backend isn't enough" |
2035 | .el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..." |
1276 | .IX Subsection "ev_embed - when one backend isn't enough" |
2036 | .IX Subsection "ev_embed - when one backend isn't enough..." |
1277 | This is a rather advanced watcher type that lets you embed one event loop |
2037 | This is a rather advanced watcher type that lets you embed one event loop |
1278 | into another (currently only \f(CW\*(C`ev_io\*(C'\fR events are supported in the embedded |
2038 | into another (currently only \f(CW\*(C`ev_io\*(C'\fR events are supported in the embedded |
1279 | loop, other types of watchers might be handled in a delayed or incorrect |
2039 | loop, other types of watchers might be handled in a delayed or incorrect |
1280 | fashion and must not be used). |
2040 | fashion and must not be used). |
1281 | .PP |
2041 | .PP |
… | |
… | |
1319 | portable one. |
2079 | portable one. |
1320 | .PP |
2080 | .PP |
1321 | So when you want to use this feature you will always have to be prepared |
2081 | So when you want to use this feature you will always have to be prepared |
1322 | that you cannot get an embeddable loop. The recommended way to get around |
2082 | that you cannot get an embeddable loop. The recommended way to get around |
1323 | this is to have a separate variables for your embeddable loop, try to |
2083 | this is to have a separate variables for your embeddable loop, try to |
1324 | create it, and if that fails, use the normal loop for everything: |
2084 | create it, and if that fails, use the normal loop for everything. |
1325 | .PP |
2085 | .PP |
1326 | .Vb 3 |
2086 | \fIWatcher-Specific Functions and Data Members\fR |
1327 | \& struct ev_loop *loop_hi = ev_default_init (0); |
2087 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1328 | \& struct ev_loop *loop_lo = 0; |
|
|
1329 | \& struct ev_embed embed; |
|
|
1330 | .Ve |
|
|
1331 | .PP |
|
|
1332 | .Vb 5 |
|
|
1333 | \& // see if there is a chance of getting one that works |
|
|
1334 | \& // (remember that a flags value of 0 means autodetection) |
|
|
1335 | \& loop_lo = ev_embeddable_backends () & ev_recommended_backends () |
|
|
1336 | \& ? ev_loop_new (ev_embeddable_backends () & ev_recommended_backends ()) |
|
|
1337 | \& : 0; |
|
|
1338 | .Ve |
|
|
1339 | .PP |
|
|
1340 | .Vb 8 |
|
|
1341 | \& // if we got one, then embed it, otherwise default to loop_hi |
|
|
1342 | \& if (loop_lo) |
|
|
1343 | \& { |
|
|
1344 | \& ev_embed_init (&embed, 0, loop_lo); |
|
|
1345 | \& ev_embed_start (loop_hi, &embed); |
|
|
1346 | \& } |
|
|
1347 | \& else |
|
|
1348 | \& loop_lo = loop_hi; |
|
|
1349 | .Ve |
|
|
1350 | .IP "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
2088 | .IP "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
1351 | .IX Item "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" |
2089 | .IX Item "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" |
1352 | .PD 0 |
2090 | .PD 0 |
1353 | .IP "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
2091 | .IP "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
1354 | .IX Item "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" |
2092 | .IX Item "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" |
… | |
… | |
1361 | .IP "ev_embed_sweep (loop, ev_embed *)" 4 |
2099 | .IP "ev_embed_sweep (loop, ev_embed *)" 4 |
1362 | .IX Item "ev_embed_sweep (loop, ev_embed *)" |
2100 | .IX Item "ev_embed_sweep (loop, ev_embed *)" |
1363 | Make a single, non-blocking sweep over the embedded loop. This works |
2101 | Make a single, non-blocking sweep over the embedded loop. This works |
1364 | similarly to \f(CW\*(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\*(C'\fR, but in the most |
2102 | similarly to \f(CW\*(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\*(C'\fR, but in the most |
1365 | apropriate way for embedded loops. |
2103 | apropriate way for embedded loops. |
|
|
2104 | .IP "struct ev_loop *other [read\-only]" 4 |
|
|
2105 | .IX Item "struct ev_loop *other [read-only]" |
|
|
2106 | The embedded event loop. |
|
|
2107 | .PP |
|
|
2108 | \fIExamples\fR |
|
|
2109 | .IX Subsection "Examples" |
|
|
2110 | .PP |
|
|
2111 | Example: Try to get an embeddable event loop and embed it into the default |
|
|
2112 | event loop. If that is not possible, use the default loop. The default |
|
|
2113 | loop is stored in \f(CW\*(C`loop_hi\*(C'\fR, while the mebeddable loop is stored in |
|
|
2114 | \&\f(CW\*(C`loop_lo\*(C'\fR (which is \f(CW\*(C`loop_hi\*(C'\fR in the acse no embeddable loop can be |
|
|
2115 | used). |
|
|
2116 | .PP |
|
|
2117 | .Vb 3 |
|
|
2118 | \& struct ev_loop *loop_hi = ev_default_init (0); |
|
|
2119 | \& struct ev_loop *loop_lo = 0; |
|
|
2120 | \& struct ev_embed embed; |
|
|
2121 | \& |
|
|
2122 | \& // see if there is a chance of getting one that works |
|
|
2123 | \& // (remember that a flags value of 0 means autodetection) |
|
|
2124 | \& loop_lo = ev_embeddable_backends () & ev_recommended_backends () |
|
|
2125 | \& ? ev_loop_new (ev_embeddable_backends () & ev_recommended_backends ()) |
|
|
2126 | \& : 0; |
|
|
2127 | \& |
|
|
2128 | \& // if we got one, then embed it, otherwise default to loop_hi |
|
|
2129 | \& if (loop_lo) |
|
|
2130 | \& { |
|
|
2131 | \& ev_embed_init (&embed, 0, loop_lo); |
|
|
2132 | \& ev_embed_start (loop_hi, &embed); |
|
|
2133 | \& } |
|
|
2134 | \& else |
|
|
2135 | \& loop_lo = loop_hi; |
|
|
2136 | .Ve |
|
|
2137 | .PP |
|
|
2138 | Example: Check if kqueue is available but not recommended and create |
|
|
2139 | a kqueue backend for use with sockets (which usually work with any |
|
|
2140 | kqueue implementation). Store the kqueue/socket\-only event loop in |
|
|
2141 | \&\f(CW\*(C`loop_socket\*(C'\fR. (One might optionally use \f(CW\*(C`EVFLAG_NOENV\*(C'\fR, too). |
|
|
2142 | .PP |
|
|
2143 | .Vb 3 |
|
|
2144 | \& struct ev_loop *loop = ev_default_init (0); |
|
|
2145 | \& struct ev_loop *loop_socket = 0; |
|
|
2146 | \& struct ev_embed embed; |
|
|
2147 | \& |
|
|
2148 | \& if (ev_supported_backends () & ~ev_recommended_backends () & EVBACKEND_KQUEUE) |
|
|
2149 | \& if ((loop_socket = ev_loop_new (EVBACKEND_KQUEUE)) |
|
|
2150 | \& { |
|
|
2151 | \& ev_embed_init (&embed, 0, loop_socket); |
|
|
2152 | \& ev_embed_start (loop, &embed); |
|
|
2153 | \& } |
|
|
2154 | \& |
|
|
2155 | \& if (!loop_socket) |
|
|
2156 | \& loop_socket = loop; |
|
|
2157 | \& |
|
|
2158 | \& // now use loop_socket for all sockets, and loop for everything else |
|
|
2159 | .Ve |
|
|
2160 | .ie n .Sh """ev_fork"" \- the audacity to resume the event loop after a fork" |
|
|
2161 | .el .Sh "\f(CWev_fork\fP \- the audacity to resume the event loop after a fork" |
|
|
2162 | .IX Subsection "ev_fork - the audacity to resume the event loop after a fork" |
|
|
2163 | Fork watchers are called when a \f(CW\*(C`fork ()\*(C'\fR was detected (usually because |
|
|
2164 | whoever is a good citizen cared to tell libev about it by calling |
|
|
2165 | \&\f(CW\*(C`ev_default_fork\*(C'\fR or \f(CW\*(C`ev_loop_fork\*(C'\fR). The invocation is done before the |
|
|
2166 | event loop blocks next and before \f(CW\*(C`ev_check\*(C'\fR watchers are being called, |
|
|
2167 | and only in the child after the fork. If whoever good citizen calling |
|
|
2168 | \&\f(CW\*(C`ev_default_fork\*(C'\fR cheats and calls it in the wrong process, the fork |
|
|
2169 | handlers will be invoked, too, of course. |
|
|
2170 | .PP |
|
|
2171 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
2172 | .IX Subsection "Watcher-Specific Functions and Data Members" |
|
|
2173 | .IP "ev_fork_init (ev_signal *, callback)" 4 |
|
|
2174 | .IX Item "ev_fork_init (ev_signal *, callback)" |
|
|
2175 | Initialises and configures the fork watcher \- it has no parameters of any |
|
|
2176 | kind. There is a \f(CW\*(C`ev_fork_set\*(C'\fR macro, but using it is utterly pointless, |
|
|
2177 | believe me. |
1366 | .SH "OTHER FUNCTIONS" |
2178 | .SH "OTHER FUNCTIONS" |
1367 | .IX Header "OTHER FUNCTIONS" |
2179 | .IX Header "OTHER FUNCTIONS" |
1368 | There are some other functions of possible interest. Described. Here. Now. |
2180 | There are some other functions of possible interest. Described. Here. Now. |
1369 | .IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4 |
2181 | .IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4 |
1370 | .IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" |
2182 | .IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" |
… | |
… | |
1394 | \& if (revents & EV_TIMEOUT) |
2206 | \& if (revents & EV_TIMEOUT) |
1395 | \& /* doh, nothing entered */; |
2207 | \& /* doh, nothing entered */; |
1396 | \& else if (revents & EV_READ) |
2208 | \& else if (revents & EV_READ) |
1397 | \& /* stdin might have data for us, joy! */; |
2209 | \& /* stdin might have data for us, joy! */; |
1398 | \& } |
2210 | \& } |
1399 | .Ve |
2211 | \& |
1400 | .Sp |
|
|
1401 | .Vb 1 |
|
|
1402 | \& ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0); |
2212 | \& ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0); |
1403 | .Ve |
2213 | .Ve |
1404 | .IP "ev_feed_event (ev_loop *, watcher *, int revents)" 4 |
2214 | .IP "ev_feed_event (ev_loop *, watcher *, int revents)" 4 |
1405 | .IX Item "ev_feed_event (ev_loop *, watcher *, int revents)" |
2215 | .IX Item "ev_feed_event (ev_loop *, watcher *, int revents)" |
1406 | Feeds the given event set into the event loop, as if the specified event |
2216 | Feeds the given event set into the event loop, as if the specified event |
… | |
… | |
1416 | loop!). |
2226 | loop!). |
1417 | .SH "LIBEVENT EMULATION" |
2227 | .SH "LIBEVENT EMULATION" |
1418 | .IX Header "LIBEVENT EMULATION" |
2228 | .IX Header "LIBEVENT EMULATION" |
1419 | Libev offers a compatibility emulation layer for libevent. It cannot |
2229 | Libev offers a compatibility emulation layer for libevent. It cannot |
1420 | emulate the internals of libevent, so here are some usage hints: |
2230 | emulate the internals of libevent, so here are some usage hints: |
|
|
2231 | .IP "\(bu" 4 |
1421 | .IP "* Use it by including <event.h>, as usual." 4 |
2232 | Use it by including <event.h>, as usual. |
1422 | .IX Item "Use it by including <event.h>, as usual." |
2233 | .IP "\(bu" 4 |
1423 | .PD 0 |
2234 | The following members are fully supported: ev_base, ev_callback, |
1424 | .IP "* The following members are fully supported: ev_base, ev_callback, ev_arg, ev_fd, ev_res, ev_events." 4 |
2235 | ev_arg, ev_fd, ev_res, ev_events. |
1425 | .IX Item "The following members are fully supported: ev_base, ev_callback, ev_arg, ev_fd, ev_res, ev_events." |
2236 | .IP "\(bu" 4 |
1426 | .IP "* Avoid using ev_flags and the EVLIST_*\-macros, while it is maintained by libev, it does not work exactly the same way as in libevent (consider it a private \s-1API\s0)." 4 |
2237 | Avoid using ev_flags and the EVLIST_*\-macros, while it is |
1427 | .IX Item "Avoid using ev_flags and the EVLIST_*-macros, while it is maintained by libev, it does not work exactly the same way as in libevent (consider it a private API)." |
2238 | maintained by libev, it does not work exactly the same way as in libevent (consider |
1428 | .IP "* Priorities are not currently supported. Initialising priorities will fail and all watchers will have the same priority, even though there is an ev_pri field." 4 |
2239 | it a private \s-1API\s0). |
1429 | .IX Item "Priorities are not currently supported. Initialising priorities will fail and all watchers will have the same priority, even though there is an ev_pri field." |
2240 | .IP "\(bu" 4 |
|
|
2241 | Priorities are not currently supported. Initialising priorities |
|
|
2242 | will fail and all watchers will have the same priority, even though there |
|
|
2243 | is an ev_pri field. |
|
|
2244 | .IP "\(bu" 4 |
1430 | .IP "* Other members are not supported." 4 |
2245 | Other members are not supported. |
1431 | .IX Item "Other members are not supported." |
2246 | .IP "\(bu" 4 |
1432 | .IP "* The libev emulation is \fInot\fR \s-1ABI\s0 compatible to libevent, you need to use the libev header file and library." 4 |
2247 | The libev emulation is \fInot\fR \s-1ABI\s0 compatible to libevent, you need |
1433 | .IX Item "The libev emulation is not ABI compatible to libevent, you need to use the libev header file and library." |
2248 | to use the libev header file and library. |
1434 | .PD |
|
|
1435 | .SH "\*(C+ SUPPORT" |
2249 | .SH "\*(C+ SUPPORT" |
1436 | .IX Header " SUPPORT" |
2250 | .IX Header " SUPPORT" |
1437 | Libev comes with some simplistic wrapper classes for \*(C+ that mainly allow |
2251 | Libev comes with some simplistic wrapper classes for \*(C+ that mainly allow |
1438 | you to use some convinience methods to start/stop watchers and also change |
2252 | you to use some convinience methods to start/stop watchers and also change |
1439 | the callback model to a model using method callbacks on objects. |
2253 | the callback model to a model using method callbacks on objects. |
… | |
… | |
1442 | .PP |
2256 | .PP |
1443 | .Vb 1 |
2257 | .Vb 1 |
1444 | \& #include <ev++.h> |
2258 | \& #include <ev++.h> |
1445 | .Ve |
2259 | .Ve |
1446 | .PP |
2260 | .PP |
1447 | (it is not installed by default). This automatically includes \fIev.h\fR |
2261 | This automatically includes \fIev.h\fR and puts all of its definitions (many |
1448 | and puts all of its definitions (many of them macros) into the global |
2262 | of them macros) into the global namespace. All \*(C+ specific things are |
1449 | namespace. All \*(C+ specific things are put into the \f(CW\*(C`ev\*(C'\fR namespace. |
2263 | put into the \f(CW\*(C`ev\*(C'\fR namespace. It should support all the same embedding |
|
|
2264 | options as \fIev.h\fR, most notably \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. |
1450 | .PP |
2265 | .PP |
1451 | It should support all the same embedding options as \fIev.h\fR, most notably |
2266 | Care has been taken to keep the overhead low. The only data member the \*(C+ |
1452 | \&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. |
2267 | classes add (compared to plain C\-style watchers) is the event loop pointer |
|
|
2268 | that the watcher is associated with (or no additional members at all if |
|
|
2269 | you disable \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR when embedding libev). |
|
|
2270 | .PP |
|
|
2271 | Currently, functions, and static and non-static member functions can be |
|
|
2272 | used as callbacks. Other types should be easy to add as long as they only |
|
|
2273 | need one additional pointer for context. If you need support for other |
|
|
2274 | types of functors please contact the author (preferably after implementing |
|
|
2275 | it). |
1453 | .PP |
2276 | .PP |
1454 | Here is a list of things available in the \f(CW\*(C`ev\*(C'\fR namespace: |
2277 | Here is a list of things available in the \f(CW\*(C`ev\*(C'\fR namespace: |
1455 | .ie n .IP """ev::READ""\fR, \f(CW""ev::WRITE"" etc." 4 |
2278 | .ie n .IP """ev::READ""\fR, \f(CW""ev::WRITE"" etc." 4 |
1456 | .el .IP "\f(CWev::READ\fR, \f(CWev::WRITE\fR etc." 4 |
2279 | .el .IP "\f(CWev::READ\fR, \f(CWev::WRITE\fR etc." 4 |
1457 | .IX Item "ev::READ, ev::WRITE etc." |
2280 | .IX Item "ev::READ, ev::WRITE etc." |
… | |
… | |
1469 | which is called \f(CW\*(C`ev::sig\*(C'\fR to avoid clashes with the \f(CW\*(C`signal\*(C'\fR macro |
2292 | which is called \f(CW\*(C`ev::sig\*(C'\fR to avoid clashes with the \f(CW\*(C`signal\*(C'\fR macro |
1470 | defines by many implementations. |
2293 | defines by many implementations. |
1471 | .Sp |
2294 | .Sp |
1472 | All of those classes have these methods: |
2295 | All of those classes have these methods: |
1473 | .RS 4 |
2296 | .RS 4 |
1474 | .IP "ev::TYPE::TYPE (object *, object::method *)" 4 |
2297 | .IP "ev::TYPE::TYPE ()" 4 |
1475 | .IX Item "ev::TYPE::TYPE (object *, object::method *)" |
2298 | .IX Item "ev::TYPE::TYPE ()" |
1476 | .PD 0 |
2299 | .PD 0 |
1477 | .IP "ev::TYPE::TYPE (object *, object::method *, struct ev_loop *)" 4 |
2300 | .IP "ev::TYPE::TYPE (struct ev_loop *)" 4 |
1478 | .IX Item "ev::TYPE::TYPE (object *, object::method *, struct ev_loop *)" |
2301 | .IX Item "ev::TYPE::TYPE (struct ev_loop *)" |
1479 | .IP "ev::TYPE::~TYPE" 4 |
2302 | .IP "ev::TYPE::~TYPE" 4 |
1480 | .IX Item "ev::TYPE::~TYPE" |
2303 | .IX Item "ev::TYPE::~TYPE" |
1481 | .PD |
2304 | .PD |
1482 | The constructor takes a pointer to an object and a method pointer to |
2305 | The constructor (optionally) takes an event loop to associate the watcher |
1483 | the event handler callback to call in this class. The constructor calls |
2306 | with. If it is omitted, it will use \f(CW\*(C`EV_DEFAULT\*(C'\fR. |
1484 | \&\f(CW\*(C`ev_init\*(C'\fR for you, which means you have to call the \f(CW\*(C`set\*(C'\fR method |
2307 | .Sp |
1485 | before starting it. If you do not specify a loop then the constructor |
2308 | The constructor calls \f(CW\*(C`ev_init\*(C'\fR for you, which means you have to call the |
1486 | automatically associates the default loop with this watcher. |
2309 | \&\f(CW\*(C`set\*(C'\fR method before starting it. |
|
|
2310 | .Sp |
|
|
2311 | It will not set a callback, however: You have to call the templated \f(CW\*(C`set\*(C'\fR |
|
|
2312 | method to set a callback before you can start the watcher. |
|
|
2313 | .Sp |
|
|
2314 | (The reason why you have to use a method is a limitation in \*(C+ which does |
|
|
2315 | not allow explicit template arguments for constructors). |
1487 | .Sp |
2316 | .Sp |
1488 | The destructor automatically stops the watcher if it is active. |
2317 | The destructor automatically stops the watcher if it is active. |
|
|
2318 | .IP "w\->set<class, &class::method> (object *)" 4 |
|
|
2319 | .IX Item "w->set<class, &class::method> (object *)" |
|
|
2320 | This method sets the callback method to call. The method has to have a |
|
|
2321 | signature of \f(CW\*(C`void (*)(ev_TYPE &, int)\*(C'\fR, it receives the watcher as |
|
|
2322 | first argument and the \f(CW\*(C`revents\*(C'\fR as second. The object must be given as |
|
|
2323 | parameter and is stored in the \f(CW\*(C`data\*(C'\fR member of the watcher. |
|
|
2324 | .Sp |
|
|
2325 | This method synthesizes efficient thunking code to call your method from |
|
|
2326 | the C callback that libev requires. If your compiler can inline your |
|
|
2327 | callback (i.e. it is visible to it at the place of the \f(CW\*(C`set\*(C'\fR call and |
|
|
2328 | your compiler is good :), then the method will be fully inlined into the |
|
|
2329 | thunking function, making it as fast as a direct C callback. |
|
|
2330 | .Sp |
|
|
2331 | Example: simple class declaration and watcher initialisation |
|
|
2332 | .Sp |
|
|
2333 | .Vb 4 |
|
|
2334 | \& struct myclass |
|
|
2335 | \& { |
|
|
2336 | \& void io_cb (ev::io &w, int revents) { } |
|
|
2337 | \& } |
|
|
2338 | \& |
|
|
2339 | \& myclass obj; |
|
|
2340 | \& ev::io iow; |
|
|
2341 | \& iow.set <myclass, &myclass::io_cb> (&obj); |
|
|
2342 | .Ve |
|
|
2343 | .IP "w\->set<function> (void *data = 0)" 4 |
|
|
2344 | .IX Item "w->set<function> (void *data = 0)" |
|
|
2345 | Also sets a callback, but uses a static method or plain function as |
|
|
2346 | callback. The optional \f(CW\*(C`data\*(C'\fR argument will be stored in the watcher's |
|
|
2347 | \&\f(CW\*(C`data\*(C'\fR member and is free for you to use. |
|
|
2348 | .Sp |
|
|
2349 | The prototype of the \f(CW\*(C`function\*(C'\fR must be \f(CW\*(C`void (*)(ev::TYPE &w, int)\*(C'\fR. |
|
|
2350 | .Sp |
|
|
2351 | See the method\-\f(CW\*(C`set\*(C'\fR above for more details. |
|
|
2352 | .Sp |
|
|
2353 | Example: |
|
|
2354 | .Sp |
|
|
2355 | .Vb 2 |
|
|
2356 | \& static void io_cb (ev::io &w, int revents) { } |
|
|
2357 | \& iow.set <io_cb> (); |
|
|
2358 | .Ve |
1489 | .IP "w\->set (struct ev_loop *)" 4 |
2359 | .IP "w\->set (struct ev_loop *)" 4 |
1490 | .IX Item "w->set (struct ev_loop *)" |
2360 | .IX Item "w->set (struct ev_loop *)" |
1491 | Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only |
2361 | Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only |
1492 | do this when the watcher is inactive (and not pending either). |
2362 | do this when the watcher is inactive (and not pending either). |
1493 | .IP "w\->set ([args])" 4 |
2363 | .IP "w\->set ([args])" 4 |
1494 | .IX Item "w->set ([args])" |
2364 | .IX Item "w->set ([args])" |
1495 | Basically the same as \f(CW\*(C`ev_TYPE_set\*(C'\fR, with the same args. Must be |
2365 | Basically the same as \f(CW\*(C`ev_TYPE_set\*(C'\fR, with the same args. Must be |
1496 | called at least once. Unlike the C counterpart, an active watcher gets |
2366 | called at least once. Unlike the C counterpart, an active watcher gets |
1497 | automatically stopped and restarted. |
2367 | automatically stopped and restarted when reconfiguring it with this |
|
|
2368 | method. |
1498 | .IP "w\->start ()" 4 |
2369 | .IP "w\->start ()" 4 |
1499 | .IX Item "w->start ()" |
2370 | .IX Item "w->start ()" |
1500 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument as the |
2371 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument, as the |
1501 | constructor already takes the loop. |
2372 | constructor already stores the event loop. |
1502 | .IP "w\->stop ()" 4 |
2373 | .IP "w\->stop ()" 4 |
1503 | .IX Item "w->stop ()" |
2374 | .IX Item "w->stop ()" |
1504 | Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument. |
2375 | Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument. |
1505 | .ie n .IP "w\->again () ""ev::timer""\fR, \f(CW""ev::periodic"" only" 4 |
2376 | .ie n .IP "w\->again () (""ev::timer""\fR, \f(CW""ev::periodic"" only)" 4 |
1506 | .el .IP "w\->again () \f(CWev::timer\fR, \f(CWev::periodic\fR only" 4 |
2377 | .el .IP "w\->again () (\f(CWev::timer\fR, \f(CWev::periodic\fR only)" 4 |
1507 | .IX Item "w->again () ev::timer, ev::periodic only" |
2378 | .IX Item "w->again () (ev::timer, ev::periodic only)" |
1508 | For \f(CW\*(C`ev::timer\*(C'\fR and \f(CW\*(C`ev::periodic\*(C'\fR, this invokes the corresponding |
2379 | For \f(CW\*(C`ev::timer\*(C'\fR and \f(CW\*(C`ev::periodic\*(C'\fR, this invokes the corresponding |
1509 | \&\f(CW\*(C`ev_TYPE_again\*(C'\fR function. |
2380 | \&\f(CW\*(C`ev_TYPE_again\*(C'\fR function. |
1510 | .ie n .IP "w\->sweep () ""ev::embed"" only" 4 |
2381 | .ie n .IP "w\->sweep () (""ev::embed"" only)" 4 |
1511 | .el .IP "w\->sweep () \f(CWev::embed\fR only" 4 |
2382 | .el .IP "w\->sweep () (\f(CWev::embed\fR only)" 4 |
1512 | .IX Item "w->sweep () ev::embed only" |
2383 | .IX Item "w->sweep () (ev::embed only)" |
1513 | Invokes \f(CW\*(C`ev_embed_sweep\*(C'\fR. |
2384 | Invokes \f(CW\*(C`ev_embed_sweep\*(C'\fR. |
|
|
2385 | .ie n .IP "w\->update () (""ev::stat"" only)" 4 |
|
|
2386 | .el .IP "w\->update () (\f(CWev::stat\fR only)" 4 |
|
|
2387 | .IX Item "w->update () (ev::stat only)" |
|
|
2388 | Invokes \f(CW\*(C`ev_stat_stat\*(C'\fR. |
1514 | .RE |
2389 | .RE |
1515 | .RS 4 |
2390 | .RS 4 |
1516 | .RE |
2391 | .RE |
1517 | .PP |
2392 | .PP |
1518 | Example: Define a class with an \s-1IO\s0 and idle watcher, start one of them in |
2393 | Example: Define a class with an \s-1IO\s0 and idle watcher, start one of them in |
1519 | the constructor. |
2394 | the constructor. |
1520 | .PP |
2395 | .PP |
1521 | .Vb 4 |
2396 | .Vb 4 |
1522 | \& class myclass |
2397 | \& class myclass |
1523 | \& { |
2398 | \& { |
1524 | \& ev_io io; void io_cb (ev::io &w, int revents); |
2399 | \& ev::io io; void io_cb (ev::io &w, int revents); |
1525 | \& ev_idle idle void idle_cb (ev::idle &w, int revents); |
2400 | \& ev:idle idle void idle_cb (ev::idle &w, int revents); |
|
|
2401 | \& |
|
|
2402 | \& myclass (int fd) |
|
|
2403 | \& { |
|
|
2404 | \& io .set <myclass, &myclass::io_cb > (this); |
|
|
2405 | \& idle.set <myclass, &myclass::idle_cb> (this); |
|
|
2406 | \& |
|
|
2407 | \& io.start (fd, ev::READ); |
|
|
2408 | \& } |
|
|
2409 | \& }; |
1526 | .Ve |
2410 | .Ve |
|
|
2411 | .SH "MACRO MAGIC" |
|
|
2412 | .IX Header "MACRO MAGIC" |
|
|
2413 | Libev can be compiled with a variety of options, the most fundamantal |
|
|
2414 | of which is \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines whether (most) |
|
|
2415 | functions and callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument. |
1527 | .PP |
2416 | .PP |
|
|
2417 | To make it easier to write programs that cope with either variant, the |
|
|
2418 | following macros are defined: |
|
|
2419 | .ie n .IP """EV_A""\fR, \f(CW""EV_A_""" 4 |
|
|
2420 | .el .IP "\f(CWEV_A\fR, \f(CWEV_A_\fR" 4 |
|
|
2421 | .IX Item "EV_A, EV_A_" |
|
|
2422 | This provides the loop \fIargument\fR for functions, if one is required (\*(L"ev |
|
|
2423 | loop argument\*(R"). The \f(CW\*(C`EV_A\*(C'\fR form is used when this is the sole argument, |
|
|
2424 | \&\f(CW\*(C`EV_A_\*(C'\fR is used when other arguments are following. Example: |
|
|
2425 | .Sp |
|
|
2426 | .Vb 3 |
|
|
2427 | \& ev_unref (EV_A); |
|
|
2428 | \& ev_timer_add (EV_A_ watcher); |
|
|
2429 | \& ev_loop (EV_A_ 0); |
|
|
2430 | .Ve |
|
|
2431 | .Sp |
|
|
2432 | It assumes the variable \f(CW\*(C`loop\*(C'\fR of type \f(CW\*(C`struct ev_loop *\*(C'\fR is in scope, |
|
|
2433 | which is often provided by the following macro. |
|
|
2434 | .ie n .IP """EV_P""\fR, \f(CW""EV_P_""" 4 |
|
|
2435 | .el .IP "\f(CWEV_P\fR, \f(CWEV_P_\fR" 4 |
|
|
2436 | .IX Item "EV_P, EV_P_" |
|
|
2437 | This provides the loop \fIparameter\fR for functions, if one is required (\*(L"ev |
|
|
2438 | loop parameter\*(R"). The \f(CW\*(C`EV_P\*(C'\fR form is used when this is the sole parameter, |
|
|
2439 | \&\f(CW\*(C`EV_P_\*(C'\fR is used when other parameters are following. Example: |
|
|
2440 | .Sp |
1528 | .Vb 2 |
2441 | .Vb 2 |
1529 | \& myclass (); |
2442 | \& // this is how ev_unref is being declared |
|
|
2443 | \& static void ev_unref (EV_P); |
|
|
2444 | \& |
|
|
2445 | \& // this is how you can declare your typical callback |
|
|
2446 | \& static void cb (EV_P_ ev_timer *w, int revents) |
|
|
2447 | .Ve |
|
|
2448 | .Sp |
|
|
2449 | It declares a parameter \f(CW\*(C`loop\*(C'\fR of type \f(CW\*(C`struct ev_loop *\*(C'\fR, quite |
|
|
2450 | suitable for use with \f(CW\*(C`EV_A\*(C'\fR. |
|
|
2451 | .ie n .IP """EV_DEFAULT""\fR, \f(CW""EV_DEFAULT_""" 4 |
|
|
2452 | .el .IP "\f(CWEV_DEFAULT\fR, \f(CWEV_DEFAULT_\fR" 4 |
|
|
2453 | .IX Item "EV_DEFAULT, EV_DEFAULT_" |
|
|
2454 | Similar to the other two macros, this gives you the value of the default |
|
|
2455 | loop, if multiple loops are supported (\*(L"ev loop default\*(R"). |
|
|
2456 | .PP |
|
|
2457 | Example: Declare and initialise a check watcher, utilising the above |
|
|
2458 | macros so it will work regardless of whether multiple loops are supported |
|
|
2459 | or not. |
|
|
2460 | .PP |
|
|
2461 | .Vb 5 |
|
|
2462 | \& static void |
|
|
2463 | \& check_cb (EV_P_ ev_timer *w, int revents) |
|
|
2464 | \& { |
|
|
2465 | \& ev_check_stop (EV_A_ w); |
1530 | \& } |
2466 | \& } |
1531 | .Ve |
2467 | \& |
1532 | .PP |
2468 | \& ev_check check; |
1533 | .Vb 6 |
2469 | \& ev_check_init (&check, check_cb); |
1534 | \& myclass::myclass (int fd) |
2470 | \& ev_check_start (EV_DEFAULT_ &check); |
1535 | \& : io (this, &myclass::io_cb), |
2471 | \& ev_loop (EV_DEFAULT_ 0); |
1536 | \& idle (this, &myclass::idle_cb) |
|
|
1537 | \& { |
|
|
1538 | \& io.start (fd, ev::READ); |
|
|
1539 | \& } |
|
|
1540 | .Ve |
2472 | .Ve |
1541 | .SH "EMBEDDING" |
2473 | .SH "EMBEDDING" |
1542 | .IX Header "EMBEDDING" |
2474 | .IX Header "EMBEDDING" |
1543 | Libev can (and often is) directly embedded into host |
2475 | Libev can (and often is) directly embedded into host |
1544 | applications. Examples of applications that embed it include the Deliantra |
2476 | applications. Examples of applications that embed it include the Deliantra |
1545 | Game Server, the \s-1EV\s0 perl module, the \s-1GNU\s0 Virtual Private Ethernet (gvpe) |
2477 | Game Server, the \s-1EV\s0 perl module, the \s-1GNU\s0 Virtual Private Ethernet (gvpe) |
1546 | and rxvt\-unicode. |
2478 | and rxvt-unicode. |
1547 | .PP |
2479 | .PP |
1548 | The goal is to enable you to just copy the neecssary files into your |
2480 | The goal is to enable you to just copy the necessary files into your |
1549 | source directory without having to change even a single line in them, so |
2481 | source directory without having to change even a single line in them, so |
1550 | you can easily upgrade by simply copying (or having a checked-out copy of |
2482 | you can easily upgrade by simply copying (or having a checked-out copy of |
1551 | libev somewhere in your source tree). |
2483 | libev somewhere in your source tree). |
1552 | .Sh "\s-1FILESETS\s0" |
2484 | .Sh "\s-1FILESETS\s0" |
1553 | .IX Subsection "FILESETS" |
2485 | .IX Subsection "FILESETS" |
… | |
… | |
1586 | .Vb 4 |
2518 | .Vb 4 |
1587 | \& ev.h |
2519 | \& ev.h |
1588 | \& ev.c |
2520 | \& ev.c |
1589 | \& ev_vars.h |
2521 | \& ev_vars.h |
1590 | \& ev_wrap.h |
2522 | \& ev_wrap.h |
1591 | .Ve |
2523 | \& |
1592 | .PP |
|
|
1593 | .Vb 1 |
|
|
1594 | \& ev_win32.c required on win32 platforms only |
2524 | \& ev_win32.c required on win32 platforms only |
1595 | .Ve |
2525 | \& |
1596 | .PP |
|
|
1597 | .Vb 5 |
|
|
1598 | \& ev_select.c only when select backend is enabled (which is is by default) |
2526 | \& ev_select.c only when select backend is enabled (which is enabled by default) |
1599 | \& ev_poll.c only when poll backend is enabled (disabled by default) |
2527 | \& ev_poll.c only when poll backend is enabled (disabled by default) |
1600 | \& ev_epoll.c only when the epoll backend is enabled (disabled by default) |
2528 | \& ev_epoll.c only when the epoll backend is enabled (disabled by default) |
1601 | \& ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
2529 | \& ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
1602 | \& ev_port.c only when the solaris port backend is enabled (disabled by default) |
2530 | \& ev_port.c only when the solaris port backend is enabled (disabled by default) |
1603 | .Ve |
2531 | .Ve |
1604 | .PP |
2532 | .PP |
1605 | \&\fIev.c\fR includes the backend files directly when enabled, so you only need |
2533 | \&\fIev.c\fR includes the backend files directly when enabled, so you only need |
1606 | to compile a single file. |
2534 | to compile this single file. |
1607 | .PP |
2535 | .PP |
1608 | \fI\s-1LIBEVENT\s0 \s-1COMPATIBILITY\s0 \s-1API\s0\fR |
2536 | \fI\s-1LIBEVENT\s0 \s-1COMPATIBILITY\s0 \s-1API\s0\fR |
1609 | .IX Subsection "LIBEVENT COMPATIBILITY API" |
2537 | .IX Subsection "LIBEVENT COMPATIBILITY API" |
1610 | .PP |
2538 | .PP |
1611 | To include the libevent compatibility \s-1API\s0, also include: |
2539 | To include the libevent compatibility \s-1API\s0, also include: |
… | |
… | |
1632 | \fI\s-1AUTOCONF\s0 \s-1SUPPORT\s0\fR |
2560 | \fI\s-1AUTOCONF\s0 \s-1SUPPORT\s0\fR |
1633 | .IX Subsection "AUTOCONF SUPPORT" |
2561 | .IX Subsection "AUTOCONF SUPPORT" |
1634 | .PP |
2562 | .PP |
1635 | Instead of using \f(CW\*(C`EV_STANDALONE=1\*(C'\fR and providing your config in |
2563 | Instead of using \f(CW\*(C`EV_STANDALONE=1\*(C'\fR and providing your config in |
1636 | whatever way you want, you can also \f(CW\*(C`m4_include([libev.m4])\*(C'\fR in your |
2564 | whatever way you want, you can also \f(CW\*(C`m4_include([libev.m4])\*(C'\fR in your |
1637 | \&\fIconfigure.ac\fR and leave \f(CW\*(C`EV_STANDALONE\*(C'\fR off. \fIev.c\fR will then include |
2565 | \&\fIconfigure.ac\fR and leave \f(CW\*(C`EV_STANDALONE\*(C'\fR undefined. \fIev.c\fR will then |
1638 | \&\fIconfig.h\fR and configure itself accordingly. |
2566 | include \fIconfig.h\fR and configure itself accordingly. |
1639 | .PP |
2567 | .PP |
1640 | For this of course you need the m4 file: |
2568 | For this of course you need the m4 file: |
1641 | .PP |
2569 | .PP |
1642 | .Vb 1 |
2570 | .Vb 1 |
1643 | \& libev.m4 |
2571 | \& libev.m4 |
… | |
… | |
1658 | .IX Item "EV_USE_MONOTONIC" |
2586 | .IX Item "EV_USE_MONOTONIC" |
1659 | If defined to be \f(CW1\fR, libev will try to detect the availability of the |
2587 | If defined to be \f(CW1\fR, libev will try to detect the availability of the |
1660 | monotonic clock option at both compiletime and runtime. Otherwise no use |
2588 | monotonic clock option at both compiletime and runtime. Otherwise no use |
1661 | of the monotonic clock option will be attempted. If you enable this, you |
2589 | of the monotonic clock option will be attempted. If you enable this, you |
1662 | usually have to link against librt or something similar. Enabling it when |
2590 | usually have to link against librt or something similar. Enabling it when |
1663 | the functionality isn't available is safe, though, althoguh you have |
2591 | the functionality isn't available is safe, though, although you have |
1664 | to make sure you link against any libraries where the \f(CW\*(C`clock_gettime\*(C'\fR |
2592 | to make sure you link against any libraries where the \f(CW\*(C`clock_gettime\*(C'\fR |
1665 | function is hiding in (often \fI\-lrt\fR). |
2593 | function is hiding in (often \fI\-lrt\fR). |
1666 | .IP "\s-1EV_USE_REALTIME\s0" 4 |
2594 | .IP "\s-1EV_USE_REALTIME\s0" 4 |
1667 | .IX Item "EV_USE_REALTIME" |
2595 | .IX Item "EV_USE_REALTIME" |
1668 | If defined to be \f(CW1\fR, libev will try to detect the availability of the |
2596 | If defined to be \f(CW1\fR, libev will try to detect the availability of the |
1669 | realtime clock option at compiletime (and assume its availability at |
2597 | realtime clock option at compiletime (and assume its availability at |
1670 | runtime if successful). Otherwise no use of the realtime clock option will |
2598 | runtime if successful). Otherwise no use of the realtime clock option will |
1671 | be attempted. This effectively replaces \f(CW\*(C`gettimeofday\*(C'\fR by \f(CW\*(C`clock_get |
2599 | be attempted. This effectively replaces \f(CW\*(C`gettimeofday\*(C'\fR by \f(CW\*(C`clock_get |
1672 | (CLOCK_REALTIME, ...)\*(C'\fR and will not normally affect correctness. See tzhe note about libraries |
2600 | (CLOCK_REALTIME, ...)\*(C'\fR and will not normally affect correctness. See the |
1673 | in the description of \f(CW\*(C`EV_USE_MONOTONIC\*(C'\fR, though. |
2601 | note about libraries in the description of \f(CW\*(C`EV_USE_MONOTONIC\*(C'\fR, though. |
|
|
2602 | .IP "\s-1EV_USE_NANOSLEEP\s0" 4 |
|
|
2603 | .IX Item "EV_USE_NANOSLEEP" |
|
|
2604 | If defined to be \f(CW1\fR, libev will assume that \f(CW\*(C`nanosleep ()\*(C'\fR is available |
|
|
2605 | and will use it for delays. Otherwise it will use \f(CW\*(C`select ()\*(C'\fR. |
1674 | .IP "\s-1EV_USE_SELECT\s0" 4 |
2606 | .IP "\s-1EV_USE_SELECT\s0" 4 |
1675 | .IX Item "EV_USE_SELECT" |
2607 | .IX Item "EV_USE_SELECT" |
1676 | If undefined or defined to be \f(CW1\fR, libev will compile in support for the |
2608 | If undefined or defined to be \f(CW1\fR, libev will compile in support for the |
1677 | \&\f(CW\*(C`select\*(C'\fR(2) backend. No attempt at autodetection will be done: if no |
2609 | \&\f(CW\*(C`select\*(C'\fR(2) backend. No attempt at autodetection will be done: if no |
1678 | other method takes over, select will be it. Otherwise the select backend |
2610 | other method takes over, select will be it. Otherwise the select backend |
… | |
… | |
1693 | wants osf handles on win32 (this is the case when the select to |
2625 | wants osf handles on win32 (this is the case when the select to |
1694 | be used is the winsock select). This means that it will call |
2626 | be used is the winsock select). This means that it will call |
1695 | \&\f(CW\*(C`_get_osfhandle\*(C'\fR on the fd to convert it to an \s-1OS\s0 handle. Otherwise, |
2627 | \&\f(CW\*(C`_get_osfhandle\*(C'\fR on the fd to convert it to an \s-1OS\s0 handle. Otherwise, |
1696 | it is assumed that all these functions actually work on fds, even |
2628 | it is assumed that all these functions actually work on fds, even |
1697 | on win32. Should not be defined on non\-win32 platforms. |
2629 | on win32. Should not be defined on non\-win32 platforms. |
|
|
2630 | .IP "\s-1EV_FD_TO_WIN32_HANDLE\s0" 4 |
|
|
2631 | .IX Item "EV_FD_TO_WIN32_HANDLE" |
|
|
2632 | If \f(CW\*(C`EV_SELECT_IS_WINSOCKET\*(C'\fR is enabled, then libev needs a way to map |
|
|
2633 | file descriptors to socket handles. When not defining this symbol (the |
|
|
2634 | default), then libev will call \f(CW\*(C`_get_osfhandle\*(C'\fR, which is usually |
|
|
2635 | correct. In some cases, programs use their own file descriptor management, |
|
|
2636 | in which case they can provide this function to map fds to socket handles. |
1698 | .IP "\s-1EV_USE_POLL\s0" 4 |
2637 | .IP "\s-1EV_USE_POLL\s0" 4 |
1699 | .IX Item "EV_USE_POLL" |
2638 | .IX Item "EV_USE_POLL" |
1700 | If defined to be \f(CW1\fR, libev will compile in support for the \f(CW\*(C`poll\*(C'\fR(2) |
2639 | If defined to be \f(CW1\fR, libev will compile in support for the \f(CW\*(C`poll\*(C'\fR(2) |
1701 | backend. Otherwise it will be enabled on non\-win32 platforms. It |
2640 | backend. Otherwise it will be enabled on non\-win32 platforms. It |
1702 | takes precedence over select. |
2641 | takes precedence over select. |
… | |
… | |
1713 | otherwise another method will be used as fallback. This is the preferred |
2652 | otherwise another method will be used as fallback. This is the preferred |
1714 | backend for \s-1BSD\s0 and BSD-like systems, although on most BSDs kqueue only |
2653 | backend for \s-1BSD\s0 and BSD-like systems, although on most BSDs kqueue only |
1715 | supports some types of fds correctly (the only platform we found that |
2654 | supports some types of fds correctly (the only platform we found that |
1716 | supports ptys for example was NetBSD), so kqueue might be compiled in, but |
2655 | supports ptys for example was NetBSD), so kqueue might be compiled in, but |
1717 | not be used unless explicitly requested. The best way to use it is to find |
2656 | not be used unless explicitly requested. The best way to use it is to find |
1718 | out wether kqueue supports your type of fd properly and use an embedded |
2657 | out whether kqueue supports your type of fd properly and use an embedded |
1719 | kqueue loop. |
2658 | kqueue loop. |
1720 | .IP "\s-1EV_USE_PORT\s0" 4 |
2659 | .IP "\s-1EV_USE_PORT\s0" 4 |
1721 | .IX Item "EV_USE_PORT" |
2660 | .IX Item "EV_USE_PORT" |
1722 | If defined to be \f(CW1\fR, libev will compile in support for the Solaris |
2661 | If defined to be \f(CW1\fR, libev will compile in support for the Solaris |
1723 | 10 port style backend. Its availability will be detected at runtime, |
2662 | 10 port style backend. Its availability will be detected at runtime, |
1724 | otherwise another method will be used as fallback. This is the preferred |
2663 | otherwise another method will be used as fallback. This is the preferred |
1725 | backend for Solaris 10 systems. |
2664 | backend for Solaris 10 systems. |
1726 | .IP "\s-1EV_USE_DEVPOLL\s0" 4 |
2665 | .IP "\s-1EV_USE_DEVPOLL\s0" 4 |
1727 | .IX Item "EV_USE_DEVPOLL" |
2666 | .IX Item "EV_USE_DEVPOLL" |
1728 | reserved for future expansion, works like the \s-1USE\s0 symbols above. |
2667 | reserved for future expansion, works like the \s-1USE\s0 symbols above. |
|
|
2668 | .IP "\s-1EV_USE_INOTIFY\s0" 4 |
|
|
2669 | .IX Item "EV_USE_INOTIFY" |
|
|
2670 | If defined to be \f(CW1\fR, libev will compile in support for the Linux inotify |
|
|
2671 | interface to speed up \f(CW\*(C`ev_stat\*(C'\fR watchers. Its actual availability will |
|
|
2672 | be detected at runtime. |
1729 | .IP "\s-1EV_H\s0" 4 |
2673 | .IP "\s-1EV_H\s0" 4 |
1730 | .IX Item "EV_H" |
2674 | .IX Item "EV_H" |
1731 | The name of the \fIev.h\fR header file used to include it. The default if |
2675 | The name of the \fIev.h\fR header file used to include it. The default if |
1732 | undefined is \f(CW\*(C`<ev.h>\*(C'\fR in \fIevent.h\fR and \f(CW"ev.h"\fR in \fIev.c\fR. This |
2676 | undefined is \f(CW"ev.h"\fR in \fIevent.h\fR, \fIev.c\fR and \fIev++.h\fR. This can be |
1733 | can be used to virtually rename the \fIev.h\fR header file in case of conflicts. |
2677 | used to virtually rename the \fIev.h\fR header file in case of conflicts. |
1734 | .IP "\s-1EV_CONFIG_H\s0" 4 |
2678 | .IP "\s-1EV_CONFIG_H\s0" 4 |
1735 | .IX Item "EV_CONFIG_H" |
2679 | .IX Item "EV_CONFIG_H" |
1736 | If \f(CW\*(C`EV_STANDALONE\*(C'\fR isn't \f(CW1\fR, this variable can be used to override |
2680 | If \f(CW\*(C`EV_STANDALONE\*(C'\fR isn't \f(CW1\fR, this variable can be used to override |
1737 | \&\fIev.c\fR's idea of where to find the \fIconfig.h\fR file, similarly to |
2681 | \&\fIev.c\fR's idea of where to find the \fIconfig.h\fR file, similarly to |
1738 | \&\f(CW\*(C`EV_H\*(C'\fR, above. |
2682 | \&\f(CW\*(C`EV_H\*(C'\fR, above. |
1739 | .IP "\s-1EV_EVENT_H\s0" 4 |
2683 | .IP "\s-1EV_EVENT_H\s0" 4 |
1740 | .IX Item "EV_EVENT_H" |
2684 | .IX Item "EV_EVENT_H" |
1741 | Similarly to \f(CW\*(C`EV_H\*(C'\fR, this macro can be used to override \fIevent.c\fR's idea |
2685 | Similarly to \f(CW\*(C`EV_H\*(C'\fR, this macro can be used to override \fIevent.c\fR's idea |
1742 | of how the \fIevent.h\fR header can be found. |
2686 | of how the \fIevent.h\fR header can be found, the default is \f(CW"event.h"\fR. |
1743 | .IP "\s-1EV_PROTOTYPES\s0" 4 |
2687 | .IP "\s-1EV_PROTOTYPES\s0" 4 |
1744 | .IX Item "EV_PROTOTYPES" |
2688 | .IX Item "EV_PROTOTYPES" |
1745 | If defined to be \f(CW0\fR, then \fIev.h\fR will not define any function |
2689 | If defined to be \f(CW0\fR, then \fIev.h\fR will not define any function |
1746 | prototypes, but still define all the structs and other symbols. This is |
2690 | prototypes, but still define all the structs and other symbols. This is |
1747 | occasionally useful if you want to provide your own wrapper functions |
2691 | occasionally useful if you want to provide your own wrapper functions |
… | |
… | |
1751 | If undefined or defined to \f(CW1\fR, then all event-loop-specific functions |
2695 | If undefined or defined to \f(CW1\fR, then all event-loop-specific functions |
1752 | will have the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument, and you can create |
2696 | will have the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument, and you can create |
1753 | additional independent event loops. Otherwise there will be no support |
2697 | additional independent event loops. Otherwise there will be no support |
1754 | for multiple event loops and there is no first event loop pointer |
2698 | for multiple event loops and there is no first event loop pointer |
1755 | argument. Instead, all functions act on the single default loop. |
2699 | argument. Instead, all functions act on the single default loop. |
|
|
2700 | .IP "\s-1EV_MINPRI\s0" 4 |
|
|
2701 | .IX Item "EV_MINPRI" |
|
|
2702 | .PD 0 |
|
|
2703 | .IP "\s-1EV_MAXPRI\s0" 4 |
|
|
2704 | .IX Item "EV_MAXPRI" |
|
|
2705 | .PD |
|
|
2706 | The range of allowed priorities. \f(CW\*(C`EV_MINPRI\*(C'\fR must be smaller or equal to |
|
|
2707 | \&\f(CW\*(C`EV_MAXPRI\*(C'\fR, but otherwise there are no non-obvious limitations. You can |
|
|
2708 | provide for more priorities by overriding those symbols (usually defined |
|
|
2709 | to be \f(CW\*(C`\-2\*(C'\fR and \f(CW2\fR, respectively). |
|
|
2710 | .Sp |
|
|
2711 | When doing priority-based operations, libev usually has to linearly search |
|
|
2712 | all the priorities, so having many of them (hundreds) uses a lot of space |
|
|
2713 | and time, so using the defaults of five priorities (\-2 .. +2) is usually |
|
|
2714 | fine. |
|
|
2715 | .Sp |
|
|
2716 | If your embedding app does not need any priorities, defining these both to |
|
|
2717 | \&\f(CW0\fR will save some memory and cpu. |
1756 | .IP "\s-1EV_PERIODICS\s0" 4 |
2718 | .IP "\s-1EV_PERIODIC_ENABLE\s0" 4 |
1757 | .IX Item "EV_PERIODICS" |
2719 | .IX Item "EV_PERIODIC_ENABLE" |
1758 | If undefined or defined to be \f(CW1\fR, then periodic timers are supported, |
2720 | If undefined or defined to be \f(CW1\fR, then periodic timers are supported. If |
1759 | otherwise not. This saves a few kb of code. |
2721 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
|
|
2722 | code. |
|
|
2723 | .IP "\s-1EV_IDLE_ENABLE\s0" 4 |
|
|
2724 | .IX Item "EV_IDLE_ENABLE" |
|
|
2725 | If undefined or defined to be \f(CW1\fR, then idle watchers are supported. If |
|
|
2726 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
|
|
2727 | code. |
|
|
2728 | .IP "\s-1EV_EMBED_ENABLE\s0" 4 |
|
|
2729 | .IX Item "EV_EMBED_ENABLE" |
|
|
2730 | If undefined or defined to be \f(CW1\fR, then embed watchers are supported. If |
|
|
2731 | defined to be \f(CW0\fR, then they are not. |
|
|
2732 | .IP "\s-1EV_STAT_ENABLE\s0" 4 |
|
|
2733 | .IX Item "EV_STAT_ENABLE" |
|
|
2734 | If undefined or defined to be \f(CW1\fR, then stat watchers are supported. If |
|
|
2735 | defined to be \f(CW0\fR, then they are not. |
|
|
2736 | .IP "\s-1EV_FORK_ENABLE\s0" 4 |
|
|
2737 | .IX Item "EV_FORK_ENABLE" |
|
|
2738 | If undefined or defined to be \f(CW1\fR, then fork watchers are supported. If |
|
|
2739 | defined to be \f(CW0\fR, then they are not. |
|
|
2740 | .IP "\s-1EV_MINIMAL\s0" 4 |
|
|
2741 | .IX Item "EV_MINIMAL" |
|
|
2742 | If you need to shave off some kilobytes of code at the expense of some |
|
|
2743 | speed, define this symbol to \f(CW1\fR. Currently only used for gcc to override |
|
|
2744 | some inlining decisions, saves roughly 30% codesize of amd64. |
|
|
2745 | .IP "\s-1EV_PID_HASHSIZE\s0" 4 |
|
|
2746 | .IX Item "EV_PID_HASHSIZE" |
|
|
2747 | \&\f(CW\*(C`ev_child\*(C'\fR watchers use a small hash table to distribute workload by |
|
|
2748 | pid. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), usually more |
|
|
2749 | than enough. If you need to manage thousands of children you might want to |
|
|
2750 | increase this value (\fImust\fR be a power of two). |
|
|
2751 | .IP "\s-1EV_INOTIFY_HASHSIZE\s0" 4 |
|
|
2752 | .IX Item "EV_INOTIFY_HASHSIZE" |
|
|
2753 | \&\f(CW\*(C`ev_stat\*(C'\fR watchers use a small hash table to distribute workload by |
|
|
2754 | inotify watch id. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), |
|
|
2755 | usually more than enough. If you need to manage thousands of \f(CW\*(C`ev_stat\*(C'\fR |
|
|
2756 | watchers you might want to increase this value (\fImust\fR be a power of |
|
|
2757 | two). |
1760 | .IP "\s-1EV_COMMON\s0" 4 |
2758 | .IP "\s-1EV_COMMON\s0" 4 |
1761 | .IX Item "EV_COMMON" |
2759 | .IX Item "EV_COMMON" |
1762 | By default, all watchers have a \f(CW\*(C`void *data\*(C'\fR member. By redefining |
2760 | By default, all watchers have a \f(CW\*(C`void *data\*(C'\fR member. By redefining |
1763 | this macro to a something else you can include more and other types of |
2761 | this macro to a something else you can include more and other types of |
1764 | members. You have to define it each time you include one of the files, |
2762 | members. You have to define it each time you include one of the files, |
… | |
… | |
1769 | .Vb 3 |
2767 | .Vb 3 |
1770 | \& #define EV_COMMON \e |
2768 | \& #define EV_COMMON \e |
1771 | \& SV *self; /* contains this struct */ \e |
2769 | \& SV *self; /* contains this struct */ \e |
1772 | \& SV *cb_sv, *fh /* note no trailing ";" */ |
2770 | \& SV *cb_sv, *fh /* note no trailing ";" */ |
1773 | .Ve |
2771 | .Ve |
1774 | .IP "\s-1EV_CB_DECLARE\s0(type)" 4 |
2772 | .IP "\s-1EV_CB_DECLARE\s0 (type)" 4 |
1775 | .IX Item "EV_CB_DECLARE(type)" |
2773 | .IX Item "EV_CB_DECLARE (type)" |
1776 | .PD 0 |
2774 | .PD 0 |
1777 | .IP "\s-1EV_CB_INVOKE\s0(watcher,revents)" 4 |
2775 | .IP "\s-1EV_CB_INVOKE\s0 (watcher, revents)" 4 |
1778 | .IX Item "EV_CB_INVOKE(watcher,revents)" |
2776 | .IX Item "EV_CB_INVOKE (watcher, revents)" |
1779 | .IP "ev_set_cb(ev,cb)" 4 |
2777 | .IP "ev_set_cb (ev, cb)" 4 |
1780 | .IX Item "ev_set_cb(ev,cb)" |
2778 | .IX Item "ev_set_cb (ev, cb)" |
1781 | .PD |
2779 | .PD |
1782 | Can be used to change the callback member declaration in each watcher, |
2780 | Can be used to change the callback member declaration in each watcher, |
1783 | and the way callbacks are invoked and set. Must expand to a struct member |
2781 | and the way callbacks are invoked and set. Must expand to a struct member |
1784 | definition and a statement, respectively. See the \fIev.v\fR header file for |
2782 | definition and a statement, respectively. See the \fIev.h\fR header file for |
1785 | their default definitions. One possible use for overriding these is to |
2783 | their default definitions. One possible use for overriding these is to |
1786 | avoid the ev_loop pointer as first argument in all cases, or to use method |
2784 | avoid the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument in all cases, or to use |
1787 | calls instead of plain function calls in \*(C+. |
2785 | method calls instead of plain function calls in \*(C+. |
|
|
2786 | .Sh "\s-1EXPORTED\s0 \s-1API\s0 \s-1SYMBOLS\s0" |
|
|
2787 | .IX Subsection "EXPORTED API SYMBOLS" |
|
|
2788 | If you need to re-export the \s-1API\s0 (e.g. via a dll) and you need a list of |
|
|
2789 | exported symbols, you can use the provided \fISymbol.*\fR files which list |
|
|
2790 | all public symbols, one per line: |
|
|
2791 | .PP |
|
|
2792 | .Vb 2 |
|
|
2793 | \& Symbols.ev for libev proper |
|
|
2794 | \& Symbols.event for the libevent emulation |
|
|
2795 | .Ve |
|
|
2796 | .PP |
|
|
2797 | This can also be used to rename all public symbols to avoid clashes with |
|
|
2798 | multiple versions of libev linked together (which is obviously bad in |
|
|
2799 | itself, but sometimes it is inconvinient to avoid this). |
|
|
2800 | .PP |
|
|
2801 | A sed command like this will create wrapper \f(CW\*(C`#define\*(C'\fR's that you need to |
|
|
2802 | include before including \fIev.h\fR: |
|
|
2803 | .PP |
|
|
2804 | .Vb 1 |
|
|
2805 | \& <Symbols.ev sed \-e "s/.*/#define & myprefix_&/" >wrap.h |
|
|
2806 | .Ve |
|
|
2807 | .PP |
|
|
2808 | This would create a file \fIwrap.h\fR which essentially looks like this: |
|
|
2809 | .PP |
|
|
2810 | .Vb 4 |
|
|
2811 | \& #define ev_backend myprefix_ev_backend |
|
|
2812 | \& #define ev_check_start myprefix_ev_check_start |
|
|
2813 | \& #define ev_check_stop myprefix_ev_check_stop |
|
|
2814 | \& ... |
|
|
2815 | .Ve |
1788 | .Sh "\s-1EXAMPLES\s0" |
2816 | .Sh "\s-1EXAMPLES\s0" |
1789 | .IX Subsection "EXAMPLES" |
2817 | .IX Subsection "EXAMPLES" |
1790 | For a real-world example of a program the includes libev |
2818 | For a real-world example of a program the includes libev |
1791 | verbatim, you can have a look at the \s-1EV\s0 perl module |
2819 | verbatim, you can have a look at the \s-1EV\s0 perl module |
1792 | (<http://software.schmorp.de/pkg/EV.html>). It has the libev files in |
2820 | (<http://software.schmorp.de/pkg/EV.html>). It has the libev files in |
1793 | the \fIlibev/\fR subdirectory and includes them in the \fI\s-1EV/EVAPI\s0.h\fR (public |
2821 | the \fIlibev/\fR subdirectory and includes them in the \fI\s-1EV/EVAPI\s0.h\fR (public |
1794 | interface) and \fI\s-1EV\s0.xs\fR (implementation) files. Only the \fI\s-1EV\s0.xs\fR file |
2822 | interface) and \fI\s-1EV\s0.xs\fR (implementation) files. Only the \fI\s-1EV\s0.xs\fR file |
1795 | will be compiled. It is pretty complex because it provides its own header |
2823 | will be compiled. It is pretty complex because it provides its own header |
1796 | file. |
2824 | file. |
1797 | .Sp |
2825 | .PP |
1798 | The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file |
2826 | The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file |
1799 | that everybody includes and which overrides some autoconf choices: |
2827 | that everybody includes and which overrides some configure choices: |
1800 | .Sp |
2828 | .PP |
1801 | .Vb 4 |
2829 | .Vb 9 |
|
|
2830 | \& #define EV_MINIMAL 1 |
1802 | \& #define EV_USE_POLL 0 |
2831 | \& #define EV_USE_POLL 0 |
1803 | \& #define EV_MULTIPLICITY 0 |
2832 | \& #define EV_MULTIPLICITY 0 |
1804 | \& #define EV_PERIODICS 0 |
2833 | \& #define EV_PERIODIC_ENABLE 0 |
|
|
2834 | \& #define EV_STAT_ENABLE 0 |
|
|
2835 | \& #define EV_FORK_ENABLE 0 |
1805 | \& #define EV_CONFIG_H <config.h> |
2836 | \& #define EV_CONFIG_H <config.h> |
1806 | .Ve |
2837 | \& #define EV_MINPRI 0 |
1807 | .Sp |
2838 | \& #define EV_MAXPRI 0 |
1808 | .Vb 1 |
2839 | \& |
1809 | \& #include "ev++.h" |
2840 | \& #include "ev++.h" |
1810 | .Ve |
2841 | .Ve |
1811 | .Sp |
2842 | .PP |
1812 | And a \fIev_cpp.C\fR implementation file that contains libev proper and is compiled: |
2843 | And a \fIev_cpp.C\fR implementation file that contains libev proper and is compiled: |
1813 | .Sp |
2844 | .PP |
1814 | .Vb 2 |
2845 | .Vb 2 |
1815 | \& #include "ev_cpp.h" |
2846 | \& #include "ev_cpp.h" |
1816 | \& #include "ev.c" |
2847 | \& #include "ev.c" |
1817 | .Ve |
2848 | .Ve |
|
|
2849 | .SH "COMPLEXITIES" |
|
|
2850 | .IX Header "COMPLEXITIES" |
|
|
2851 | In this section the complexities of (many of) the algorithms used inside |
|
|
2852 | libev will be explained. For complexity discussions about backends see the |
|
|
2853 | documentation for \f(CW\*(C`ev_default_init\*(C'\fR. |
|
|
2854 | .PP |
|
|
2855 | All of the following are about amortised time: If an array needs to be |
|
|
2856 | extended, libev needs to realloc and move the whole array, but this |
|
|
2857 | happens asymptotically never with higher number of elements, so O(1) might |
|
|
2858 | mean it might do a lengthy realloc operation in rare cases, but on average |
|
|
2859 | it is much faster and asymptotically approaches constant time. |
|
|
2860 | .IP "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" 4 |
|
|
2861 | .IX Item "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" |
|
|
2862 | This means that, when you have a watcher that triggers in one hour and |
|
|
2863 | there are 100 watchers that would trigger before that then inserting will |
|
|
2864 | have to skip roughly seven (\f(CW\*(C`ld 100\*(C'\fR) of these watchers. |
|
|
2865 | .IP "Changing timer/periodic watchers (by autorepeat or calling again): O(log skipped_other_timers)" 4 |
|
|
2866 | .IX Item "Changing timer/periodic watchers (by autorepeat or calling again): O(log skipped_other_timers)" |
|
|
2867 | That means that changing a timer costs less than removing/adding them |
|
|
2868 | as only the relative motion in the event queue has to be paid for. |
|
|
2869 | .IP "Starting io/check/prepare/idle/signal/child watchers: O(1)" 4 |
|
|
2870 | .IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)" |
|
|
2871 | These just add the watcher into an array or at the head of a list. |
|
|
2872 | .IP "Stopping check/prepare/idle watchers: O(1)" 4 |
|
|
2873 | .IX Item "Stopping check/prepare/idle watchers: O(1)" |
|
|
2874 | .PD 0 |
|
|
2875 | .IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % \s-1EV_PID_HASHSIZE\s0))" 4 |
|
|
2876 | .IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))" |
|
|
2877 | .PD |
|
|
2878 | These watchers are stored in lists then need to be walked to find the |
|
|
2879 | correct watcher to remove. The lists are usually short (you don't usually |
|
|
2880 | have many watchers waiting for the same fd or signal). |
|
|
2881 | .IP "Finding the next timer in each loop iteration: O(1)" 4 |
|
|
2882 | .IX Item "Finding the next timer in each loop iteration: O(1)" |
|
|
2883 | By virtue of using a binary heap, the next timer is always found at the |
|
|
2884 | beginning of the storage array. |
|
|
2885 | .IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4 |
|
|
2886 | .IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" |
|
|
2887 | A change means an I/O watcher gets started or stopped, which requires |
|
|
2888 | libev to recalculate its status (and possibly tell the kernel, depending |
|
|
2889 | on backend and wether \f(CW\*(C`ev_io_set\*(C'\fR was used). |
|
|
2890 | .IP "Activating one watcher (putting it into the pending state): O(1)" 4 |
|
|
2891 | .IX Item "Activating one watcher (putting it into the pending state): O(1)" |
|
|
2892 | .PD 0 |
|
|
2893 | .IP "Priority handling: O(number_of_priorities)" 4 |
|
|
2894 | .IX Item "Priority handling: O(number_of_priorities)" |
|
|
2895 | .PD |
|
|
2896 | Priorities are implemented by allocating some space for each |
|
|
2897 | priority. When doing priority-based operations, libev usually has to |
|
|
2898 | linearly search all the priorities, but starting/stopping and activating |
|
|
2899 | watchers becomes O(1) w.r.t. prioritiy handling. |
|
|
2900 | .SH "Win32 platform limitations and workarounds" |
|
|
2901 | .IX Header "Win32 platform limitations and workarounds" |
|
|
2902 | Win32 doesn't support any of the standards (e.g. \s-1POSIX\s0) that libev |
|
|
2903 | requires, and its I/O model is fundamentally incompatible with the \s-1POSIX\s0 |
|
|
2904 | model. Libev still offers limited functionality on this platform in |
|
|
2905 | the form of the \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR backend, and only supports socket |
|
|
2906 | descriptors. This only applies when using Win32 natively, not when using |
|
|
2907 | e.g. cygwin. |
|
|
2908 | .PP |
|
|
2909 | There is no supported compilation method available on windows except |
|
|
2910 | embedding it into other applications. |
|
|
2911 | .PP |
|
|
2912 | Due to the many, low, and arbitrary limits on the win32 platform and the |
|
|
2913 | abysmal performance of winsockets, using a large number of sockets is not |
|
|
2914 | recommended (and not reasonable). If your program needs to use more than |
|
|
2915 | a hundred or so sockets, then likely it needs to use a totally different |
|
|
2916 | implementation for windows, as libev offers the \s-1POSIX\s0 model, which cannot |
|
|
2917 | be implemented efficiently on windows (microsoft monopoly games). |
|
|
2918 | .IP "The winsocket select function" 4 |
|
|
2919 | .IX Item "The winsocket select function" |
|
|
2920 | The winsocket \f(CW\*(C`select\*(C'\fR function doesn't follow \s-1POSIX\s0 in that it requires |
|
|
2921 | socket \fIhandles\fR and not socket \fIfile descriptors\fR. This makes select |
|
|
2922 | very inefficient, and also requires a mapping from file descriptors |
|
|
2923 | to socket handles. See the discussion of the \f(CW\*(C`EV_SELECT_USE_FD_SET\*(C'\fR, |
|
|
2924 | \&\f(CW\*(C`EV_SELECT_IS_WINSOCKET\*(C'\fR and \f(CW\*(C`EV_FD_TO_WIN32_HANDLE\*(C'\fR preprocessor |
|
|
2925 | symbols for more info. |
|
|
2926 | .Sp |
|
|
2927 | The configuration for a \*(L"naked\*(R" win32 using the microsoft runtime |
|
|
2928 | libraries and raw winsocket select is: |
|
|
2929 | .Sp |
|
|
2930 | .Vb 2 |
|
|
2931 | \& #define EV_USE_SELECT 1 |
|
|
2932 | \& #define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */ |
|
|
2933 | .Ve |
|
|
2934 | .Sp |
|
|
2935 | Note that winsockets handling of fd sets is O(n), so you can easily get a |
|
|
2936 | complexity in the O(nA\*^X) range when using win32. |
|
|
2937 | .IP "Limited number of file descriptors" 4 |
|
|
2938 | .IX Item "Limited number of file descriptors" |
|
|
2939 | Windows has numerous arbitrary (and low) limits on things. Early versions |
|
|
2940 | of winsocket's select only supported waiting for a max. of \f(CW64\fR handles |
|
|
2941 | (probably owning to the fact that all windows kernels can only wait for |
|
|
2942 | \&\f(CW64\fR things at the same time internally; microsoft recommends spawning a |
|
|
2943 | chain of threads and wait for 63 handles and the previous thread in each). |
|
|
2944 | .Sp |
|
|
2945 | Newer versions support more handles, but you need to define \f(CW\*(C`FD_SETSIZE\*(C'\fR |
|
|
2946 | to some high number (e.g. \f(CW2048\fR) before compiling the winsocket select |
|
|
2947 | call (which might be in libev or elsewhere, for example, perl does its own |
|
|
2948 | select emulation on windows). |
|
|
2949 | .Sp |
|
|
2950 | Another limit is the number of file descriptors in the microsoft runtime |
|
|
2951 | libraries, which by default is \f(CW64\fR (there must be a hidden \fI64\fR fetish |
|
|
2952 | or something like this inside microsoft). You can increase this by calling |
|
|
2953 | \&\f(CW\*(C`_setmaxstdio\*(C'\fR, which can increase this limit to \f(CW2048\fR (another |
|
|
2954 | arbitrary limit), but is broken in many versions of the microsoft runtime |
|
|
2955 | libraries. |
|
|
2956 | .Sp |
|
|
2957 | This might get you to about \f(CW512\fR or \f(CW2048\fR sockets (depending on |
|
|
2958 | windows version and/or the phase of the moon). To get more, you need to |
|
|
2959 | wrap all I/O functions and provide your own fd management, but the cost of |
|
|
2960 | calling select (O(nA\*^X)) will likely make this unworkable. |
1818 | .SH "AUTHOR" |
2961 | .SH "AUTHOR" |
1819 | .IX Header "AUTHOR" |
2962 | .IX Header "AUTHOR" |
1820 | Marc Lehmann <libev@schmorp.de>. |
2963 | Marc Lehmann <libev@schmorp.de>. |
|
|
2964 | .SH "POD ERRORS" |
|
|
2965 | .IX Header "POD ERRORS" |
|
|
2966 | Hey! \fBThe above document had some coding errors, which are explained below:\fR |
|
|
2967 | .IP "Around line 2686:" 4 |
|
|
2968 | .IX Item "Around line 2686:" |
|
|
2969 | You forgot a '=back' before '=head2' |