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128 | .rm #[ #] #H #V #F C |
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129 | .\" ======================================================================== |
132 | .\" ======================================================================== |
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133 | .\" |
131 | .IX Title "EV 1" |
134 | .IX Title "EV 1" |
132 | .TH EV 1 "2007-12-25" "perl v5.8.8" "User Contributed Perl Documentation" |
135 | .TH EV 1 "2008-03-13" "perl v5.10.0" "User Contributed Perl Documentation" |
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136 | .\" For nroff, turn off justification. Always turn off hyphenation; it makes |
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137 | .\" way too many mistakes in technical documents. |
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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 |
140 | .Sh "\s-1EXAMPLE\s0 \s-1PROGRAM\s0" |
147 | .Sh "\s-1EXAMPLE\s0 \s-1PROGRAM\s0" |
141 | .IX Subsection "EXAMPLE PROGRAM" |
148 | .IX Subsection "EXAMPLE PROGRAM" |
142 | .Vb 1 |
149 | .Vb 2 |
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150 | \& // a single header file is required |
143 | \& #include <ev.h> |
151 | \& #include <ev.h> |
144 | .Ve |
152 | \& |
145 | .PP |
153 | \& // every watcher type has its own typedef\*(Aqd struct |
146 | .Vb 2 |
154 | \& // with the name ev_<type> |
147 | \& ev_io stdin_watcher; |
155 | \& ev_io stdin_watcher; |
148 | \& ev_timer timeout_watcher; |
156 | \& ev_timer timeout_watcher; |
149 | .Ve |
157 | \& |
150 | .PP |
158 | \& // all watcher callbacks have a similar signature |
151 | .Vb 8 |
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152 | \& /* called when data readable on stdin */ |
159 | \& // this callback is called when data is readable on stdin |
153 | \& static void |
160 | \& static void |
154 | \& stdin_cb (EV_P_ struct ev_io *w, int revents) |
161 | \& stdin_cb (EV_P_ struct ev_io *w, int revents) |
155 | \& { |
162 | \& { |
156 | \& /* puts ("stdin ready"); */ |
163 | \& puts ("stdin ready"); |
157 | \& ev_io_stop (EV_A_ w); /* just a syntax example */ |
164 | \& // for one\-shot events, one must manually stop the watcher |
158 | \& ev_unloop (EV_A_ EVUNLOOP_ALL); /* leave all loop calls */ |
165 | \& // with its corresponding stop function. |
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166 | \& ev_io_stop (EV_A_ w); |
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167 | \& |
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168 | \& // this causes all nested ev_loop\*(Aqs to stop iterating |
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169 | \& ev_unloop (EV_A_ EVUNLOOP_ALL); |
159 | \& } |
170 | \& } |
160 | .Ve |
171 | \& |
161 | .PP |
172 | \& // another callback, this time for a time\-out |
162 | .Vb 6 |
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163 | \& static void |
173 | \& static void |
164 | \& timeout_cb (EV_P_ struct ev_timer *w, int revents) |
174 | \& timeout_cb (EV_P_ struct ev_timer *w, int revents) |
165 | \& { |
175 | \& { |
166 | \& /* puts ("timeout"); */ |
176 | \& puts ("timeout"); |
167 | \& ev_unloop (EV_A_ EVUNLOOP_ONE); /* leave one loop call */ |
177 | \& // this causes the innermost ev_loop to stop iterating |
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178 | \& ev_unloop (EV_A_ EVUNLOOP_ONE); |
168 | \& } |
179 | \& } |
169 | .Ve |
180 | \& |
170 | .PP |
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171 | .Vb 4 |
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172 | \& int |
181 | \& int |
173 | \& main (void) |
182 | \& main (void) |
174 | \& { |
183 | \& { |
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184 | \& // use the default event loop unless you have special needs |
175 | \& struct ev_loop *loop = ev_default_loop (0); |
185 | \& struct ev_loop *loop = ev_default_loop (0); |
176 | .Ve |
186 | \& |
177 | .PP |
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178 | .Vb 3 |
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179 | \& /* initialise an io watcher, then start it */ |
187 | \& // initialise an io watcher, then start it |
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188 | \& // this one will watch for stdin to become readable |
180 | \& ev_io_init (&stdin_watcher, stdin_cb, /*STDIN_FILENO*/ 0, EV_READ); |
189 | \& ev_io_init (&stdin_watcher, stdin_cb, /*STDIN_FILENO*/ 0, EV_READ); |
181 | \& ev_io_start (loop, &stdin_watcher); |
190 | \& ev_io_start (loop, &stdin_watcher); |
182 | .Ve |
191 | \& |
183 | .PP |
192 | \& // initialise a timer watcher, then start it |
184 | .Vb 3 |
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185 | \& /* simple non-repeating 5.5 second timeout */ |
193 | \& // simple non\-repeating 5.5 second timeout |
186 | \& ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.); |
194 | \& ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.); |
187 | \& ev_timer_start (loop, &timeout_watcher); |
195 | \& ev_timer_start (loop, &timeout_watcher); |
188 | .Ve |
196 | \& |
189 | .PP |
197 | \& // now wait for events to arrive |
190 | .Vb 2 |
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191 | \& /* loop till timeout or data ready */ |
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192 | \& ev_loop (loop, 0); |
198 | \& ev_loop (loop, 0); |
193 | .Ve |
199 | \& |
194 | .PP |
200 | \& // unloop was called, so exit |
195 | .Vb 2 |
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196 | \& return 0; |
201 | \& return 0; |
197 | \& } |
202 | \& } |
198 | .Ve |
203 | .Ve |
199 | .SH "DESCRIPTION" |
204 | .SH "DESCRIPTION" |
200 | .IX Header "DESCRIPTION" |
205 | .IX Header "DESCRIPTION" |
201 | The newest version of this document is also available as a html-formatted |
206 | The newest version of this document is also available as an html-formatted |
202 | web page you might find easier to navigate when reading it for the first |
207 | web page you might find easier to navigate when reading it for the first |
203 | time: <http://cvs.schmorp.de/libev/ev.html>. |
208 | time: <http://cvs.schmorp.de/libev/ev.html>. |
204 | .PP |
209 | .PP |
205 | Libev is an event loop: you register interest in certain events (such as a |
210 | Libev is an event loop: you register interest in certain events (such as a |
206 | file descriptor being readable or a timeout occurring), and it will manage |
211 | file descriptor being readable or a timeout occurring), and it will manage |
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230 | It also is quite fast (see this |
235 | It also is quite fast (see this |
231 | benchmark comparing it to libevent |
236 | benchmark comparing it to libevent |
232 | for example). |
237 | for example). |
233 | .Sh "\s-1CONVENTIONS\s0" |
238 | .Sh "\s-1CONVENTIONS\s0" |
234 | .IX Subsection "CONVENTIONS" |
239 | .IX Subsection "CONVENTIONS" |
235 | Libev is very configurable. In this manual the default configuration will |
240 | Libev is very configurable. In this manual the default (and most common) |
236 | be described, which supports multiple event loops. For more info about |
241 | configuration will be described, which supports multiple event loops. For |
237 | various configuration options please have a look at \fB\s-1EMBED\s0\fR section in |
242 | more info about various configuration options please have a look at |
238 | this manual. If libev was configured without support for multiple event |
243 | \&\fB\s-1EMBED\s0\fR section in this manual. If libev was configured without support |
239 | loops, then all functions taking an initial argument of name \f(CW\*(C`loop\*(C'\fR |
244 | for multiple event loops, then all functions taking an initial argument of |
240 | (which is always of type \f(CW\*(C`struct ev_loop *\*(C'\fR) will not have this argument. |
245 | name \f(CW\*(C`loop\*(C'\fR (which is always of type \f(CW\*(C`struct ev_loop *\*(C'\fR) will not have |
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246 | this argument. |
241 | .Sh "\s-1TIME\s0 \s-1REPRESENTATION\s0" |
247 | .Sh "\s-1TIME\s0 \s-1REPRESENTATION\s0" |
242 | .IX Subsection "TIME REPRESENTATION" |
248 | .IX Subsection "TIME REPRESENTATION" |
243 | Libev represents time as a single floating point number, representing the |
249 | Libev represents time as a single floating point number, representing the |
244 | (fractional) number of seconds since the (\s-1POSIX\s0) epoch (somewhere near |
250 | (fractional) number of seconds since the (\s-1POSIX\s0) epoch (somewhere near |
245 | the beginning of 1970, details are complicated, don't ask). This type is |
251 | the beginning of 1970, details are complicated, don't ask). This type is |
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313 | (assuming you know what you are doing). This is the set of backends that |
319 | (assuming you know what you are doing). This is the set of backends that |
314 | libev will probe for if you specify no backends explicitly. |
320 | libev will probe for if you specify no backends explicitly. |
315 | .IP "unsigned int ev_embeddable_backends ()" 4 |
321 | .IP "unsigned int ev_embeddable_backends ()" 4 |
316 | .IX Item "unsigned int ev_embeddable_backends ()" |
322 | .IX Item "unsigned int ev_embeddable_backends ()" |
317 | Returns the set of backends that are embeddable in other event loops. This |
323 | Returns the set of backends that are embeddable in other event loops. This |
318 | is the theoretical, all\-platform, value. To find which backends |
324 | is the theoretical, all-platform, value. To find which backends |
319 | might be supported on the current system, you would need to look at |
325 | might be supported on the current system, you would need to look at |
320 | \&\f(CW\*(C`ev_embeddable_backends () & ev_supported_backends ()\*(C'\fR, likewise for |
326 | \&\f(CW\*(C`ev_embeddable_backends () & ev_supported_backends ()\*(C'\fR, likewise for |
321 | recommended ones. |
327 | recommended ones. |
322 | .Sp |
328 | .Sp |
323 | See the description of \f(CW\*(C`ev_embed\*(C'\fR watchers for more info. |
329 | See the description of \f(CW\*(C`ev_embed\*(C'\fR watchers for more info. |
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342 | \& persistent_realloc (void *ptr, size_t size) |
348 | \& persistent_realloc (void *ptr, size_t size) |
343 | \& { |
349 | \& { |
344 | \& for (;;) |
350 | \& for (;;) |
345 | \& { |
351 | \& { |
346 | \& void *newptr = realloc (ptr, size); |
352 | \& void *newptr = realloc (ptr, size); |
347 | .Ve |
353 | \& |
348 | .Sp |
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349 | .Vb 2 |
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350 | \& if (newptr) |
354 | \& if (newptr) |
351 | \& return newptr; |
355 | \& return newptr; |
352 | .Ve |
356 | \& |
353 | .Sp |
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354 | .Vb 3 |
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355 | \& sleep (60); |
357 | \& sleep (60); |
356 | \& } |
358 | \& } |
357 | \& } |
359 | \& } |
358 | .Ve |
360 | \& |
359 | .Sp |
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360 | .Vb 2 |
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361 | \& ... |
361 | \& ... |
362 | \& ev_set_allocator (persistent_realloc); |
362 | \& ev_set_allocator (persistent_realloc); |
363 | .Ve |
363 | .Ve |
364 | .IP "ev_set_syserr_cb (void (*cb)(const char *msg));" 4 |
364 | .IP "ev_set_syserr_cb (void (*cb)(const char *msg));" 4 |
365 | .IX Item "ev_set_syserr_cb (void (*cb)(const char *msg));" |
365 | .IX Item "ev_set_syserr_cb (void (*cb)(const char *msg));" |
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378 | \& fatal_error (const char *msg) |
378 | \& fatal_error (const char *msg) |
379 | \& { |
379 | \& { |
380 | \& perror (msg); |
380 | \& perror (msg); |
381 | \& abort (); |
381 | \& abort (); |
382 | \& } |
382 | \& } |
383 | .Ve |
383 | \& |
384 | .Sp |
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385 | .Vb 2 |
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386 | \& ... |
384 | \& ... |
387 | \& ev_set_syserr_cb (fatal_error); |
385 | \& ev_set_syserr_cb (fatal_error); |
388 | .Ve |
386 | .Ve |
389 | .SH "FUNCTIONS CONTROLLING THE EVENT LOOP" |
387 | .SH "FUNCTIONS CONTROLLING THE EVENT LOOP" |
390 | .IX Header "FUNCTIONS CONTROLLING THE EVENT LOOP" |
388 | .IX Header "FUNCTIONS CONTROLLING THE EVENT LOOP" |
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405 | false. If it already was initialised it simply returns it (and ignores the |
403 | false. If it already was initialised it simply returns it (and ignores the |
406 | flags. If that is troubling you, check \f(CW\*(C`ev_backend ()\*(C'\fR afterwards). |
404 | flags. If that is troubling you, check \f(CW\*(C`ev_backend ()\*(C'\fR afterwards). |
407 | .Sp |
405 | .Sp |
408 | If you don't know what event loop to use, use the one returned from this |
406 | If you don't know what event loop to use, use the one returned from this |
409 | function. |
407 | function. |
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408 | .Sp |
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409 | The default loop is the only loop that can handle \f(CW\*(C`ev_signal\*(C'\fR and |
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410 | \&\f(CW\*(C`ev_child\*(C'\fR watchers, and to do this, it always registers a handler |
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411 | for \f(CW\*(C`SIGCHLD\*(C'\fR. If this is a problem for your app you can either |
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412 | create a dynamic loop with \f(CW\*(C`ev_loop_new\*(C'\fR that doesn't do that, or you |
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413 | can simply overwrite the \f(CW\*(C`SIGCHLD\*(C'\fR signal handler \fIafter\fR calling |
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414 | \&\f(CW\*(C`ev_default_init\*(C'\fR. |
410 | .Sp |
415 | .Sp |
411 | The flags argument can be used to specify special behaviour or specific |
416 | The flags argument can be used to specify special behaviour or specific |
412 | backends to use, and is usually specified as \f(CW0\fR (or \f(CW\*(C`EVFLAG_AUTO\*(C'\fR). |
417 | backends to use, and is usually specified as \f(CW0\fR (or \f(CW\*(C`EVFLAG_AUTO\*(C'\fR). |
413 | .Sp |
418 | .Sp |
414 | The following flags are supported: |
419 | The following flags are supported: |
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435 | enabling this flag. |
440 | enabling this flag. |
436 | .Sp |
441 | .Sp |
437 | This works by calling \f(CW\*(C`getpid ()\*(C'\fR on every iteration of the loop, |
442 | This works by calling \f(CW\*(C`getpid ()\*(C'\fR on every iteration of the loop, |
438 | and thus this might slow down your event loop if you do a lot of loop |
443 | and thus this might slow down your event loop if you do a lot of loop |
439 | iterations and little real work, but is usually not noticeable (on my |
444 | iterations and little real work, but is usually not noticeable (on my |
440 | Linux system for example, \f(CW\*(C`getpid\*(C'\fR is actually a simple 5\-insn sequence |
445 | GNU/Linux system for example, \f(CW\*(C`getpid\*(C'\fR is actually a simple 5\-insn sequence |
441 | without a syscall and thus \fIvery\fR fast, but my Linux system also has |
446 | without a syscall and thus \fIvery\fR fast, but my GNU/Linux system also has |
442 | \&\f(CW\*(C`pthread_atfork\*(C'\fR which is even faster). |
447 | \&\f(CW\*(C`pthread_atfork\*(C'\fR which is even faster). |
443 | .Sp |
448 | .Sp |
444 | The big advantage of this flag is that you can forget about fork (and |
449 | The big advantage of this flag is that you can forget about fork (and |
445 | forget about forgetting to tell libev about forking) when you use this |
450 | forget about forgetting to tell libev about forking) when you use this |
446 | flag. |
451 | flag. |
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452 | .IX Item "EVBACKEND_SELECT (value 1, portable select backend)" |
457 | .IX Item "EVBACKEND_SELECT (value 1, portable select backend)" |
453 | This is your standard \fIselect\fR\|(2) backend. Not \fIcompletely\fR standard, as |
458 | This is your standard \fIselect\fR\|(2) backend. Not \fIcompletely\fR standard, as |
454 | libev tries to roll its own fd_set with no limits on the number of fds, |
459 | libev tries to roll its own fd_set with no limits on the number of fds, |
455 | but if that fails, expect a fairly low limit on the number of fds when |
460 | but if that fails, expect a fairly low limit on the number of fds when |
456 | using this backend. It doesn't scale too well (O(highest_fd)), but its |
461 | using this backend. It doesn't scale too well (O(highest_fd)), but its |
457 | usually the fastest backend for a low number of (low\-numbered :) fds. |
462 | usually the fastest backend for a low number of (low-numbered :) fds. |
458 | .Sp |
463 | .Sp |
459 | To get good performance out of this backend you need a high amount of |
464 | To get good performance out of this backend you need a high amount of |
460 | parallelity (most of the file descriptors should be busy). If you are |
465 | parallelity (most of the file descriptors should be busy). If you are |
461 | writing a server, you should \f(CW\*(C`accept ()\*(C'\fR in a loop to accept as many |
466 | writing a server, you should \f(CW\*(C`accept ()\*(C'\fR in a loop to accept as many |
462 | connections as possible during one iteration. You might also want to have |
467 | connections as possible during one iteration. You might also want to have |
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547 | .Sp |
552 | .Sp |
548 | While this backend scales well, it requires one system call per active |
553 | While this backend scales well, it requires one system call per active |
549 | file descriptor per loop iteration. For small and medium numbers of file |
554 | file descriptor per loop iteration. For small and medium numbers of file |
550 | descriptors a \*(L"slow\*(R" \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR or \f(CW\*(C`EVBACKEND_POLL\*(C'\fR backend |
555 | descriptors a \*(L"slow\*(R" \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR or \f(CW\*(C`EVBACKEND_POLL\*(C'\fR backend |
551 | might perform better. |
556 | might perform better. |
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557 | .Sp |
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558 | On the positive side, ignoring the spurious readyness notifications, this |
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559 | backend actually performed to specification in all tests and is fully |
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560 | embeddable, which is a rare feat among the OS-specific backends. |
552 | .ie n .IP """EVBACKEND_ALL""" 4 |
561 | .ie n .IP """EVBACKEND_ALL""" 4 |
553 | .el .IP "\f(CWEVBACKEND_ALL\fR" 4 |
562 | .el .IP "\f(CWEVBACKEND_ALL\fR" 4 |
554 | .IX Item "EVBACKEND_ALL" |
563 | .IX Item "EVBACKEND_ALL" |
555 | Try all backends (even potentially broken ones that wouldn't be tried |
564 | Try all backends (even potentially broken ones that wouldn't be tried |
556 | with \f(CW\*(C`EVFLAG_AUTO\*(C'\fR). Since this is a mask, you can do stuff such as |
565 | with \f(CW\*(C`EVFLAG_AUTO\*(C'\fR). Since this is a mask, you can do stuff such as |
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559 | It is definitely not recommended to use this flag. |
568 | It is definitely not recommended to use this flag. |
560 | .RE |
569 | .RE |
561 | .RS 4 |
570 | .RS 4 |
562 | .Sp |
571 | .Sp |
563 | If one or more of these are ored into the flags value, then only these |
572 | If one or more of these are ored into the flags value, then only these |
564 | backends will be tried (in the reverse order as given here). If none are |
573 | backends will be tried (in the reverse order as listed here). If none are |
565 | specified, most compiled-in backend will be tried, usually in reverse |
574 | specified, all backends in \f(CW\*(C`ev_recommended_backends ()\*(C'\fR will be tried. |
566 | order of their flag values :) |
|
|
567 | .Sp |
575 | .Sp |
568 | The most typical usage is like this: |
576 | The most typical usage is like this: |
569 | .Sp |
577 | .Sp |
570 | .Vb 2 |
578 | .Vb 2 |
571 | \& if (!ev_default_loop (0)) |
579 | \& if (!ev_default_loop (0)) |
… | |
… | |
623 | .IX Item "ev_loop_destroy (loop)" |
631 | .IX Item "ev_loop_destroy (loop)" |
624 | Like \f(CW\*(C`ev_default_destroy\*(C'\fR, but destroys an event loop created by an |
632 | Like \f(CW\*(C`ev_default_destroy\*(C'\fR, but destroys an event loop created by an |
625 | earlier call to \f(CW\*(C`ev_loop_new\*(C'\fR. |
633 | earlier call to \f(CW\*(C`ev_loop_new\*(C'\fR. |
626 | .IP "ev_default_fork ()" 4 |
634 | .IP "ev_default_fork ()" 4 |
627 | .IX Item "ev_default_fork ()" |
635 | .IX Item "ev_default_fork ()" |
|
|
636 | This function sets a flag that causes subsequent \f(CW\*(C`ev_loop\*(C'\fR iterations |
628 | This function reinitialises the kernel state for backends that have |
637 | to reinitialise the kernel state for backends that have one. Despite the |
629 | one. Despite the name, you can call it anytime, but it makes most sense |
638 | name, you can call it anytime, but it makes most sense after forking, in |
630 | after forking, in either the parent or child process (or both, but that |
639 | the child process (or both child and parent, but that again makes little |
631 | again makes little sense). |
640 | sense). You \fImust\fR call it in the child before using any of the libev |
|
|
641 | functions, and it will only take effect at the next \f(CW\*(C`ev_loop\*(C'\fR iteration. |
632 | .Sp |
642 | .Sp |
633 | You \fImust\fR call this function in the child process after forking if and |
643 | On the other hand, you only need to call this function in the child |
634 | only if you want to use the event library in both processes. If you just |
644 | process if and only if you want to use the event library in the child. If |
635 | fork+exec, you don't have to call it. |
645 | you just fork+exec, you don't have to call it at all. |
636 | .Sp |
646 | .Sp |
637 | The function itself is quite fast and it's usually not a problem to call |
647 | The function itself is quite fast and it's usually not a problem to call |
638 | it just in case after a fork. To make this easy, the function will fit in |
648 | it just in case after a fork. To make this easy, the function will fit in |
639 | quite nicely into a call to \f(CW\*(C`pthread_atfork\*(C'\fR: |
649 | quite nicely into a call to \f(CW\*(C`pthread_atfork\*(C'\fR: |
640 | .Sp |
650 | .Sp |
641 | .Vb 1 |
651 | .Vb 1 |
642 | \& pthread_atfork (0, 0, ev_default_fork); |
652 | \& pthread_atfork (0, 0, ev_default_fork); |
643 | .Ve |
653 | .Ve |
644 | .Sp |
|
|
645 | At the moment, \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR and \f(CW\*(C`EVBACKEND_POLL\*(C'\fR are safe to use |
|
|
646 | without calling this function, so if you force one of those backends you |
|
|
647 | do not need to care. |
|
|
648 | .IP "ev_loop_fork (loop)" 4 |
654 | .IP "ev_loop_fork (loop)" 4 |
649 | .IX Item "ev_loop_fork (loop)" |
655 | .IX Item "ev_loop_fork (loop)" |
650 | Like \f(CW\*(C`ev_default_fork\*(C'\fR, but acts on an event loop created by |
656 | Like \f(CW\*(C`ev_default_fork\*(C'\fR, but acts on an event loop created by |
651 | \&\f(CW\*(C`ev_loop_new\*(C'\fR. Yes, you have to call this on every allocated event loop |
657 | \&\f(CW\*(C`ev_loop_new\*(C'\fR. Yes, you have to call this on every allocated event loop |
652 | after fork, and how you do this is entirely your own problem. |
658 | after fork, and how you do this is entirely your own problem. |
|
|
659 | .IP "int ev_is_default_loop (loop)" 4 |
|
|
660 | .IX Item "int ev_is_default_loop (loop)" |
|
|
661 | Returns true when the given loop actually is the default loop, false otherwise. |
653 | .IP "unsigned int ev_loop_count (loop)" 4 |
662 | .IP "unsigned int ev_loop_count (loop)" 4 |
654 | .IX Item "unsigned int ev_loop_count (loop)" |
663 | .IX Item "unsigned int ev_loop_count (loop)" |
655 | Returns the count of loop iterations for the loop, which is identical to |
664 | Returns the count of loop iterations for the loop, which is identical to |
656 | the number of times libev did poll for new events. It starts at \f(CW0\fR and |
665 | the number of times libev did poll for new events. It starts at \f(CW0\fR and |
657 | happily wraps around with enough iterations. |
666 | happily wraps around with enough iterations. |
… | |
… | |
697 | libev watchers. However, a pair of \f(CW\*(C`ev_prepare\*(C'\fR/\f(CW\*(C`ev_check\*(C'\fR watchers is |
706 | libev watchers. However, a pair of \f(CW\*(C`ev_prepare\*(C'\fR/\f(CW\*(C`ev_check\*(C'\fR watchers is |
698 | usually a better approach for this kind of thing. |
707 | usually a better approach for this kind of thing. |
699 | .Sp |
708 | .Sp |
700 | Here are the gory details of what \f(CW\*(C`ev_loop\*(C'\fR does: |
709 | Here are the gory details of what \f(CW\*(C`ev_loop\*(C'\fR does: |
701 | .Sp |
710 | .Sp |
702 | .Vb 19 |
711 | .Vb 10 |
703 | \& - Before the first iteration, call any pending watchers. |
712 | \& \- Before the first iteration, call any pending watchers. |
704 | \& * If there are no active watchers (reference count is zero), return. |
713 | \& * If EVFLAG_FORKCHECK was used, check for a fork. |
705 | \& - Queue all prepare watchers and then call all outstanding watchers. |
714 | \& \- If a fork was detected, queue and call all fork watchers. |
|
|
715 | \& \- Queue and call all prepare watchers. |
706 | \& - If we have been forked, recreate the kernel state. |
716 | \& \- If we have been forked, recreate the kernel state. |
707 | \& - Update the kernel state with all outstanding changes. |
717 | \& \- Update the kernel state with all outstanding changes. |
708 | \& - Update the "event loop time". |
718 | \& \- Update the "event loop time". |
709 | \& - Calculate for how long to block. |
719 | \& \- Calculate for how long to sleep or block, if at all |
|
|
720 | \& (active idle watchers, EVLOOP_NONBLOCK or not having |
|
|
721 | \& any active watchers at all will result in not sleeping). |
|
|
722 | \& \- Sleep if the I/O and timer collect interval say so. |
710 | \& - Block the process, waiting for any events. |
723 | \& \- Block the process, waiting for any events. |
711 | \& - Queue all outstanding I/O (fd) events. |
724 | \& \- Queue all outstanding I/O (fd) events. |
712 | \& - Update the "event loop time" and do time jump handling. |
725 | \& \- Update the "event loop time" and do time jump handling. |
713 | \& - Queue all outstanding timers. |
726 | \& \- Queue all outstanding timers. |
714 | \& - Queue all outstanding periodics. |
727 | \& \- Queue all outstanding periodics. |
715 | \& - If no events are pending now, queue all idle watchers. |
728 | \& \- If no events are pending now, queue all idle watchers. |
716 | \& - Queue all check watchers. |
729 | \& \- Queue all check watchers. |
717 | \& - Call all queued watchers in reverse order (i.e. check watchers first). |
730 | \& \- Call all queued watchers in reverse order (i.e. check watchers first). |
718 | \& Signals and child watchers are implemented as I/O watchers, and will |
731 | \& Signals and child watchers are implemented as I/O watchers, and will |
719 | \& be handled here by queueing them when their watcher gets executed. |
732 | \& be handled here by queueing them when their watcher gets executed. |
720 | \& - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
733 | \& \- If ev_unloop has been called, or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
721 | \& were used, return, otherwise continue with step *. |
734 | \& were used, or there are no active watchers, return, otherwise |
|
|
735 | \& continue with step *. |
722 | .Ve |
736 | .Ve |
723 | .Sp |
737 | .Sp |
724 | Example: Queue some jobs and then loop until no events are outsanding |
738 | Example: Queue some jobs and then loop until no events are outstanding |
725 | anymore. |
739 | anymore. |
726 | .Sp |
740 | .Sp |
727 | .Vb 4 |
741 | .Vb 4 |
728 | \& ... queue jobs here, make sure they register event watchers as long |
742 | \& ... queue jobs here, make sure they register event watchers as long |
729 | \& ... as they still have work to do (even an idle watcher will do..) |
743 | \& ... as they still have work to do (even an idle watcher will do..) |
… | |
… | |
734 | .IX Item "ev_unloop (loop, how)" |
748 | .IX Item "ev_unloop (loop, how)" |
735 | Can be used to make a call to \f(CW\*(C`ev_loop\*(C'\fR return early (but only after it |
749 | Can be used to make a call to \f(CW\*(C`ev_loop\*(C'\fR return early (but only after it |
736 | has processed all outstanding events). The \f(CW\*(C`how\*(C'\fR argument must be either |
750 | has processed all outstanding events). The \f(CW\*(C`how\*(C'\fR argument must be either |
737 | \&\f(CW\*(C`EVUNLOOP_ONE\*(C'\fR, which will make the innermost \f(CW\*(C`ev_loop\*(C'\fR call return, or |
751 | \&\f(CW\*(C`EVUNLOOP_ONE\*(C'\fR, which will make the innermost \f(CW\*(C`ev_loop\*(C'\fR call return, or |
738 | \&\f(CW\*(C`EVUNLOOP_ALL\*(C'\fR, which will make all nested \f(CW\*(C`ev_loop\*(C'\fR calls return. |
752 | \&\f(CW\*(C`EVUNLOOP_ALL\*(C'\fR, which will make all nested \f(CW\*(C`ev_loop\*(C'\fR calls return. |
|
|
753 | .Sp |
|
|
754 | This \*(L"unloop state\*(R" will be cleared when entering \f(CW\*(C`ev_loop\*(C'\fR again. |
739 | .IP "ev_ref (loop)" 4 |
755 | .IP "ev_ref (loop)" 4 |
740 | .IX Item "ev_ref (loop)" |
756 | .IX Item "ev_ref (loop)" |
741 | .PD 0 |
757 | .PD 0 |
742 | .IP "ev_unref (loop)" 4 |
758 | .IP "ev_unref (loop)" 4 |
743 | .IX Item "ev_unref (loop)" |
759 | .IX Item "ev_unref (loop)" |
… | |
… | |
749 | returning, \fIev_unref()\fR after starting, and \fIev_ref()\fR before stopping it. For |
765 | returning, \fIev_unref()\fR after starting, and \fIev_ref()\fR before stopping it. For |
750 | example, libev itself uses this for its internal signal pipe: It is not |
766 | example, libev itself uses this for its internal signal pipe: It is not |
751 | visible to the libev user and should not keep \f(CW\*(C`ev_loop\*(C'\fR from exiting if |
767 | visible to the libev user and should not keep \f(CW\*(C`ev_loop\*(C'\fR from exiting if |
752 | no event watchers registered by it are active. It is also an excellent |
768 | no event watchers registered by it are active. It is also an excellent |
753 | way to do this for generic recurring timers or from within third-party |
769 | way to do this for generic recurring timers or from within third-party |
754 | libraries. Just remember to \fIunref after start\fR and \fIref before stop\fR. |
770 | libraries. Just remember to \fIunref after start\fR and \fIref before stop\fR |
|
|
771 | (but only if the watcher wasn't active before, or was active before, |
|
|
772 | respectively). |
755 | .Sp |
773 | .Sp |
756 | Example: Create a signal watcher, but keep it from keeping \f(CW\*(C`ev_loop\*(C'\fR |
774 | Example: Create a signal watcher, but keep it from keeping \f(CW\*(C`ev_loop\*(C'\fR |
757 | running when nothing else is active. |
775 | running when nothing else is active. |
758 | .Sp |
776 | .Sp |
759 | .Vb 4 |
777 | .Vb 4 |
… | |
… | |
816 | \& static void my_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
834 | \& static void my_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
817 | \& { |
835 | \& { |
818 | \& ev_io_stop (w); |
836 | \& ev_io_stop (w); |
819 | \& ev_unloop (loop, EVUNLOOP_ALL); |
837 | \& ev_unloop (loop, EVUNLOOP_ALL); |
820 | \& } |
838 | \& } |
821 | .Ve |
839 | \& |
822 | .PP |
|
|
823 | .Vb 6 |
|
|
824 | \& struct ev_loop *loop = ev_default_loop (0); |
840 | \& struct ev_loop *loop = ev_default_loop (0); |
825 | \& struct ev_io stdin_watcher; |
841 | \& struct ev_io stdin_watcher; |
826 | \& ev_init (&stdin_watcher, my_cb); |
842 | \& ev_init (&stdin_watcher, my_cb); |
827 | \& ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ); |
843 | \& ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ); |
828 | \& ev_io_start (loop, &stdin_watcher); |
844 | \& ev_io_start (loop, &stdin_watcher); |
… | |
… | |
916 | .ie n .IP """EV_FORK""" 4 |
932 | .ie n .IP """EV_FORK""" 4 |
917 | .el .IP "\f(CWEV_FORK\fR" 4 |
933 | .el .IP "\f(CWEV_FORK\fR" 4 |
918 | .IX Item "EV_FORK" |
934 | .IX Item "EV_FORK" |
919 | The event loop has been resumed in the child process after fork (see |
935 | The event loop has been resumed in the child process after fork (see |
920 | \&\f(CW\*(C`ev_fork\*(C'\fR). |
936 | \&\f(CW\*(C`ev_fork\*(C'\fR). |
|
|
937 | .ie n .IP """EV_ASYNC""" 4 |
|
|
938 | .el .IP "\f(CWEV_ASYNC\fR" 4 |
|
|
939 | .IX Item "EV_ASYNC" |
|
|
940 | The given async watcher has been asynchronously notified (see \f(CW\*(C`ev_async\*(C'\fR). |
921 | .ie n .IP """EV_ERROR""" 4 |
941 | .ie n .IP """EV_ERROR""" 4 |
922 | .el .IP "\f(CWEV_ERROR\fR" 4 |
942 | .el .IP "\f(CWEV_ERROR\fR" 4 |
923 | .IX Item "EV_ERROR" |
943 | .IX Item "EV_ERROR" |
924 | An unspecified error has occured, the watcher has been stopped. This might |
944 | An unspecified error has occured, the watcher has been stopped. This might |
925 | happen because the watcher could not be properly started because libev |
945 | happen because the watcher could not be properly started because libev |
… | |
… | |
1089 | In this case getting the pointer to \f(CW\*(C`my_biggy\*(C'\fR is a bit more complicated, |
1109 | In this case getting the pointer to \f(CW\*(C`my_biggy\*(C'\fR is a bit more complicated, |
1090 | you need to use \f(CW\*(C`offsetof\*(C'\fR: |
1110 | you need to use \f(CW\*(C`offsetof\*(C'\fR: |
1091 | .PP |
1111 | .PP |
1092 | .Vb 1 |
1112 | .Vb 1 |
1093 | \& #include <stddef.h> |
1113 | \& #include <stddef.h> |
1094 | .Ve |
1114 | \& |
1095 | .PP |
|
|
1096 | .Vb 6 |
|
|
1097 | \& static void |
1115 | \& static void |
1098 | \& t1_cb (EV_P_ struct ev_timer *w, int revents) |
1116 | \& t1_cb (EV_P_ struct ev_timer *w, int revents) |
1099 | \& { |
1117 | \& { |
1100 | \& struct my_biggy big = (struct my_biggy * |
1118 | \& struct my_biggy big = (struct my_biggy * |
1101 | \& (((char *)w) - offsetof (struct my_biggy, t1)); |
1119 | \& (((char *)w) \- offsetof (struct my_biggy, t1)); |
1102 | \& } |
1120 | \& } |
1103 | .Ve |
1121 | \& |
1104 | .PP |
|
|
1105 | .Vb 6 |
|
|
1106 | \& static void |
1122 | \& static void |
1107 | \& t2_cb (EV_P_ struct ev_timer *w, int revents) |
1123 | \& t2_cb (EV_P_ struct ev_timer *w, int revents) |
1108 | \& { |
1124 | \& { |
1109 | \& struct my_biggy big = (struct my_biggy * |
1125 | \& struct my_biggy big = (struct my_biggy * |
1110 | \& (((char *)w) - offsetof (struct my_biggy, t2)); |
1126 | \& (((char *)w) \- offsetof (struct my_biggy, t2)); |
1111 | \& } |
1127 | \& } |
1112 | .Ve |
1128 | .Ve |
1113 | .SH "WATCHER TYPES" |
1129 | .SH "WATCHER TYPES" |
1114 | .IX Header "WATCHER TYPES" |
1130 | .IX Header "WATCHER TYPES" |
1115 | This section describes each watcher in detail, but will not repeat |
1131 | This section describes each watcher in detail, but will not repeat |
… | |
… | |
1221 | The file descriptor being watched. |
1237 | The file descriptor being watched. |
1222 | .IP "int events [read\-only]" 4 |
1238 | .IP "int events [read\-only]" 4 |
1223 | .IX Item "int events [read-only]" |
1239 | .IX Item "int events [read-only]" |
1224 | The events being watched. |
1240 | The events being watched. |
1225 | .PP |
1241 | .PP |
|
|
1242 | \fIExamples\fR |
|
|
1243 | .IX Subsection "Examples" |
|
|
1244 | .PP |
1226 | Example: Call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well |
1245 | Example: Call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well |
1227 | readable, but only once. Since it is likely line\-buffered, you could |
1246 | readable, but only once. Since it is likely line-buffered, you could |
1228 | attempt to read a whole line in the callback. |
1247 | attempt to read a whole line in the callback. |
1229 | .PP |
1248 | .PP |
1230 | .Vb 6 |
1249 | .Vb 6 |
1231 | \& static void |
1250 | \& static void |
1232 | \& stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
1251 | \& stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
1233 | \& { |
1252 | \& { |
1234 | \& ev_io_stop (loop, w); |
1253 | \& ev_io_stop (loop, w); |
1235 | \& .. read from stdin here (or from w->fd) and haqndle any I/O errors |
1254 | \& .. read from stdin here (or from w\->fd) and haqndle any I/O errors |
1236 | \& } |
1255 | \& } |
1237 | .Ve |
1256 | \& |
1238 | .PP |
|
|
1239 | .Vb 6 |
|
|
1240 | \& ... |
1257 | \& ... |
1241 | \& struct ev_loop *loop = ev_default_init (0); |
1258 | \& struct ev_loop *loop = ev_default_init (0); |
1242 | \& struct ev_io stdin_readable; |
1259 | \& struct ev_io stdin_readable; |
1243 | \& ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ); |
1260 | \& ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ); |
1244 | \& ev_io_start (loop, &stdin_readable); |
1261 | \& ev_io_start (loop, &stdin_readable); |
… | |
… | |
1261 | of the event triggering whatever timeout you are modifying/starting. If |
1278 | of the event triggering whatever timeout you are modifying/starting. If |
1262 | you suspect event processing to be delayed and you \fIneed\fR to base the timeout |
1279 | you suspect event processing to be delayed and you \fIneed\fR to base the timeout |
1263 | on the current time, use something like this to adjust for this: |
1280 | on the current time, use something like this to adjust for this: |
1264 | .PP |
1281 | .PP |
1265 | .Vb 1 |
1282 | .Vb 1 |
1266 | \& ev_timer_set (&timer, after + ev_now () - ev_time (), 0.); |
1283 | \& ev_timer_set (&timer, after + ev_now () \- ev_time (), 0.); |
1267 | .Ve |
1284 | .Ve |
1268 | .PP |
1285 | .PP |
1269 | The callback is guarenteed to be invoked only when its timeout has passed, |
1286 | The callback is guarenteed to be invoked only when its timeout has passed, |
1270 | but if multiple timers become ready during the same loop iteration then |
1287 | but if multiple timers become ready during the same loop iteration then |
1271 | order of execution is undefined. |
1288 | order of execution is undefined. |
… | |
… | |
1286 | The timer itself will do a best-effort at avoiding drift, that is, if you |
1303 | The timer itself will do a best-effort at avoiding drift, that is, if you |
1287 | configure a timer to trigger every 10 seconds, then it will trigger at |
1304 | configure a timer to trigger every 10 seconds, then it will trigger at |
1288 | exactly 10 second intervals. If, however, your program cannot keep up with |
1305 | exactly 10 second intervals. If, however, your program cannot keep up with |
1289 | the timer (because it takes longer than those 10 seconds to do stuff) the |
1306 | the timer (because it takes longer than those 10 seconds to do stuff) the |
1290 | timer will not fire more than once per event loop iteration. |
1307 | timer will not fire more than once per event loop iteration. |
1291 | .IP "ev_timer_again (loop)" 4 |
1308 | .IP "ev_timer_again (loop, ev_timer *)" 4 |
1292 | .IX Item "ev_timer_again (loop)" |
1309 | .IX Item "ev_timer_again (loop, ev_timer *)" |
1293 | This will act as if the timer timed out and restart it again if it is |
1310 | This will act as if the timer timed out and restart it again if it is |
1294 | repeating. The exact semantics are: |
1311 | repeating. The exact semantics are: |
1295 | .Sp |
1312 | .Sp |
1296 | If the timer is pending, its pending status is cleared. |
1313 | If the timer is pending, its pending status is cleared. |
1297 | .Sp |
1314 | .Sp |
… | |
… | |
1315 | .Sp |
1332 | .Sp |
1316 | .Vb 8 |
1333 | .Vb 8 |
1317 | \& ev_timer_init (timer, callback, 0., 5.); |
1334 | \& ev_timer_init (timer, callback, 0., 5.); |
1318 | \& ev_timer_again (loop, timer); |
1335 | \& ev_timer_again (loop, timer); |
1319 | \& ... |
1336 | \& ... |
1320 | \& timer->again = 17.; |
1337 | \& timer\->again = 17.; |
1321 | \& ev_timer_again (loop, timer); |
1338 | \& ev_timer_again (loop, timer); |
1322 | \& ... |
1339 | \& ... |
1323 | \& timer->again = 10.; |
1340 | \& timer\->again = 10.; |
1324 | \& ev_timer_again (loop, timer); |
1341 | \& ev_timer_again (loop, timer); |
1325 | .Ve |
1342 | .Ve |
1326 | .Sp |
1343 | .Sp |
1327 | This is more slightly efficient then stopping/starting the timer each time |
1344 | This is more slightly efficient then stopping/starting the timer each time |
1328 | you want to modify its timeout value. |
1345 | you want to modify its timeout value. |
… | |
… | |
1330 | .IX Item "ev_tstamp repeat [read-write]" |
1347 | .IX Item "ev_tstamp repeat [read-write]" |
1331 | The current \f(CW\*(C`repeat\*(C'\fR value. Will be used each time the watcher times out |
1348 | The current \f(CW\*(C`repeat\*(C'\fR value. Will be used each time the watcher times out |
1332 | or \f(CW\*(C`ev_timer_again\*(C'\fR is called and determines the next timeout (if any), |
1349 | or \f(CW\*(C`ev_timer_again\*(C'\fR is called and determines the next timeout (if any), |
1333 | which is also when any modifications are taken into account. |
1350 | which is also when any modifications are taken into account. |
1334 | .PP |
1351 | .PP |
|
|
1352 | \fIExamples\fR |
|
|
1353 | .IX Subsection "Examples" |
|
|
1354 | .PP |
1335 | Example: Create a timer that fires after 60 seconds. |
1355 | Example: Create a timer that fires after 60 seconds. |
1336 | .PP |
1356 | .PP |
1337 | .Vb 5 |
1357 | .Vb 5 |
1338 | \& static void |
1358 | \& static void |
1339 | \& one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1359 | \& one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1340 | \& { |
1360 | \& { |
1341 | \& .. one minute over, w is actually stopped right here |
1361 | \& .. one minute over, w is actually stopped right here |
1342 | \& } |
1362 | \& } |
1343 | .Ve |
1363 | \& |
1344 | .PP |
|
|
1345 | .Vb 3 |
|
|
1346 | \& struct ev_timer mytimer; |
1364 | \& struct ev_timer mytimer; |
1347 | \& ev_timer_init (&mytimer, one_minute_cb, 60., 0.); |
1365 | \& ev_timer_init (&mytimer, one_minute_cb, 60., 0.); |
1348 | \& ev_timer_start (loop, &mytimer); |
1366 | \& ev_timer_start (loop, &mytimer); |
1349 | .Ve |
1367 | .Ve |
1350 | .PP |
1368 | .PP |
… | |
… | |
1355 | \& static void |
1373 | \& static void |
1356 | \& timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1374 | \& timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1357 | \& { |
1375 | \& { |
1358 | \& .. ten seconds without any activity |
1376 | \& .. ten seconds without any activity |
1359 | \& } |
1377 | \& } |
1360 | .Ve |
1378 | \& |
1361 | .PP |
|
|
1362 | .Vb 4 |
|
|
1363 | \& struct ev_timer mytimer; |
1379 | \& struct ev_timer mytimer; |
1364 | \& ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */ |
1380 | \& ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */ |
1365 | \& ev_timer_again (&mytimer); /* start timer */ |
1381 | \& ev_timer_again (&mytimer); /* start timer */ |
1366 | \& ev_loop (loop, 0); |
1382 | \& ev_loop (loop, 0); |
1367 | .Ve |
1383 | \& |
1368 | .PP |
|
|
1369 | .Vb 3 |
|
|
1370 | \& // and in some piece of code that gets executed on any "activity": |
1384 | \& // and in some piece of code that gets executed on any "activity": |
1371 | \& // reset the timeout to start ticking again at 10 seconds |
1385 | \& // reset the timeout to start ticking again at 10 seconds |
1372 | \& ev_timer_again (&mytimer); |
1386 | \& ev_timer_again (&mytimer); |
1373 | .Ve |
1387 | .Ve |
1374 | .ie n .Sh """ev_periodic"" \- to cron or not to cron?" |
1388 | .ie n .Sh """ev_periodic"" \- to cron or not to cron?" |
… | |
… | |
1402 | .IX Item "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" |
1416 | .IX Item "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" |
1403 | .PD |
1417 | .PD |
1404 | Lots of arguments, lets sort it out... There are basically three modes of |
1418 | Lots of arguments, lets sort it out... There are basically three modes of |
1405 | operation, and we will explain them from simplest to complex: |
1419 | operation, and we will explain them from simplest to complex: |
1406 | .RS 4 |
1420 | .RS 4 |
|
|
1421 | .IP "\(bu" 4 |
1407 | .IP "* absolute timer (at = time, interval = reschedule_cb = 0)" 4 |
1422 | absolute timer (at = time, interval = reschedule_cb = 0) |
1408 | .IX Item "absolute timer (at = time, interval = reschedule_cb = 0)" |
1423 | .Sp |
1409 | In this configuration the watcher triggers an event at the wallclock time |
1424 | In this configuration the watcher triggers an event at the wallclock time |
1410 | \&\f(CW\*(C`at\*(C'\fR and doesn't repeat. It will not adjust when a time jump occurs, |
1425 | \&\f(CW\*(C`at\*(C'\fR and doesn't repeat. It will not adjust when a time jump occurs, |
1411 | that is, if it is to be run at January 1st 2011 then it will run when the |
1426 | that is, if it is to be run at January 1st 2011 then it will run when the |
1412 | system time reaches or surpasses this time. |
1427 | system time reaches or surpasses this time. |
|
|
1428 | .IP "\(bu" 4 |
1413 | .IP "* non-repeating interval timer (at = offset, interval > 0, reschedule_cb = 0)" 4 |
1429 | repeating interval timer (at = offset, interval > 0, reschedule_cb = 0) |
1414 | .IX Item "non-repeating interval timer (at = offset, interval > 0, reschedule_cb = 0)" |
1430 | .Sp |
1415 | In this mode the watcher will always be scheduled to time out at the next |
1431 | In this mode the watcher will always be scheduled to time out at the next |
1416 | \&\f(CW\*(C`at + N * interval\*(C'\fR time (for some integer N, which can also be negative) |
1432 | \&\f(CW\*(C`at + N * interval\*(C'\fR time (for some integer N, which can also be negative) |
1417 | and then repeat, regardless of any time jumps. |
1433 | and then repeat, regardless of any time jumps. |
1418 | .Sp |
1434 | .Sp |
1419 | This can be used to create timers that do not drift with respect to system |
1435 | This can be used to create timers that do not drift with respect to system |
… | |
… | |
1433 | time where \f(CW\*(C`time = at (mod interval)\*(C'\fR, regardless of any time jumps. |
1449 | time where \f(CW\*(C`time = at (mod interval)\*(C'\fR, regardless of any time jumps. |
1434 | .Sp |
1450 | .Sp |
1435 | For numerical stability it is preferable that the \f(CW\*(C`at\*(C'\fR value is near |
1451 | For numerical stability it is preferable that the \f(CW\*(C`at\*(C'\fR value is near |
1436 | \&\f(CW\*(C`ev_now ()\*(C'\fR (the current time), but there is no range requirement for |
1452 | \&\f(CW\*(C`ev_now ()\*(C'\fR (the current time), but there is no range requirement for |
1437 | this value. |
1453 | this value. |
|
|
1454 | .IP "\(bu" 4 |
1438 | .IP "* manual reschedule mode (at and interval ignored, reschedule_cb = callback)" 4 |
1455 | manual reschedule mode (at and interval ignored, reschedule_cb = callback) |
1439 | .IX Item "manual reschedule mode (at and interval ignored, reschedule_cb = callback)" |
1456 | .Sp |
1440 | In this mode the values for \f(CW\*(C`interval\*(C'\fR and \f(CW\*(C`at\*(C'\fR are both being |
1457 | In this mode the values for \f(CW\*(C`interval\*(C'\fR and \f(CW\*(C`at\*(C'\fR are both being |
1441 | ignored. Instead, each time the periodic watcher gets scheduled, the |
1458 | ignored. Instead, each time the periodic watcher gets scheduled, the |
1442 | reschedule callback will be called with the watcher as first, and the |
1459 | reschedule callback will be called with the watcher as first, and the |
1443 | current time as second argument. |
1460 | current time as second argument. |
1444 | .Sp |
1461 | .Sp |
… | |
… | |
1499 | .IP "ev_tstamp at [read\-only]" 4 |
1516 | .IP "ev_tstamp at [read\-only]" 4 |
1500 | .IX Item "ev_tstamp at [read-only]" |
1517 | .IX Item "ev_tstamp at [read-only]" |
1501 | When active, contains the absolute time that the watcher is supposed to |
1518 | When active, contains the absolute time that the watcher is supposed to |
1502 | trigger next. |
1519 | trigger next. |
1503 | .PP |
1520 | .PP |
|
|
1521 | \fIExamples\fR |
|
|
1522 | .IX Subsection "Examples" |
|
|
1523 | .PP |
1504 | Example: Call a callback every hour, or, more precisely, whenever the |
1524 | Example: Call a callback every hour, or, more precisely, whenever the |
1505 | system clock is divisible by 3600. The callback invocation times have |
1525 | system clock is divisible by 3600. The callback invocation times have |
1506 | potentially a lot of jittering, but good long-term stability. |
1526 | potentially a lot of jittering, but good long-term stability. |
1507 | .PP |
1527 | .PP |
1508 | .Vb 5 |
1528 | .Vb 5 |
1509 | \& static void |
1529 | \& static void |
1510 | \& clock_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
1530 | \& clock_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
1511 | \& { |
1531 | \& { |
1512 | \& ... its now a full hour (UTC, or TAI or whatever your clock follows) |
1532 | \& ... its now a full hour (UTC, or TAI or whatever your clock follows) |
1513 | \& } |
1533 | \& } |
1514 | .Ve |
1534 | \& |
1515 | .PP |
|
|
1516 | .Vb 3 |
|
|
1517 | \& struct ev_periodic hourly_tick; |
1535 | \& struct ev_periodic hourly_tick; |
1518 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); |
1536 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); |
1519 | \& ev_periodic_start (loop, &hourly_tick); |
1537 | \& ev_periodic_start (loop, &hourly_tick); |
1520 | .Ve |
1538 | .Ve |
1521 | .PP |
1539 | .PP |
1522 | Example: The same as above, but use a reschedule callback to do it: |
1540 | Example: The same as above, but use a reschedule callback to do it: |
1523 | .PP |
1541 | .PP |
1524 | .Vb 1 |
1542 | .Vb 1 |
1525 | \& #include <math.h> |
1543 | \& #include <math.h> |
1526 | .Ve |
1544 | \& |
1527 | .PP |
|
|
1528 | .Vb 5 |
|
|
1529 | \& static ev_tstamp |
1545 | \& static ev_tstamp |
1530 | \& my_scheduler_cb (struct ev_periodic *w, ev_tstamp now) |
1546 | \& my_scheduler_cb (struct ev_periodic *w, ev_tstamp now) |
1531 | \& { |
1547 | \& { |
1532 | \& return fmod (now, 3600.) + 3600.; |
1548 | \& return fmod (now, 3600.) + 3600.; |
1533 | \& } |
1549 | \& } |
1534 | .Ve |
1550 | \& |
1535 | .PP |
|
|
1536 | .Vb 1 |
|
|
1537 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); |
1551 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); |
1538 | .Ve |
1552 | .Ve |
1539 | .PP |
1553 | .PP |
1540 | Example: Call a callback every hour, starting now: |
1554 | Example: Call a callback every hour, starting now: |
1541 | .PP |
1555 | .PP |
… | |
… | |
1557 | first watcher gets started will libev actually register a signal watcher |
1571 | first watcher gets started will libev actually register a signal watcher |
1558 | with the kernel (thus it coexists with your own signal handlers as long |
1572 | with the kernel (thus it coexists with your own signal handlers as long |
1559 | as you don't register any with libev). Similarly, when the last signal |
1573 | as you don't register any with libev). Similarly, when the last signal |
1560 | watcher for a signal is stopped libev will reset the signal handler to |
1574 | watcher for a signal is stopped libev will reset the signal handler to |
1561 | \&\s-1SIG_DFL\s0 (regardless of what it was set to before). |
1575 | \&\s-1SIG_DFL\s0 (regardless of what it was set to before). |
|
|
1576 | .PP |
|
|
1577 | If possible and supported, libev will install its handlers with |
|
|
1578 | \&\f(CW\*(C`SA_RESTART\*(C'\fR behaviour enabled, so syscalls should not be unduly |
|
|
1579 | interrupted. If you have a problem with syscalls getting interrupted by |
|
|
1580 | signals you can block all signals in an \f(CW\*(C`ev_check\*(C'\fR watcher and unblock |
|
|
1581 | them in an \f(CW\*(C`ev_prepare\*(C'\fR watcher. |
1562 | .PP |
1582 | .PP |
1563 | \fIWatcher-Specific Functions and Data Members\fR |
1583 | \fIWatcher-Specific Functions and Data Members\fR |
1564 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1584 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1565 | .IP "ev_signal_init (ev_signal *, callback, int signum)" 4 |
1585 | .IP "ev_signal_init (ev_signal *, callback, int signum)" 4 |
1566 | .IX Item "ev_signal_init (ev_signal *, callback, int signum)" |
1586 | .IX Item "ev_signal_init (ev_signal *, callback, int signum)" |
… | |
… | |
1571 | Configures the watcher to trigger on the given signal number (usually one |
1591 | Configures the watcher to trigger on the given signal number (usually one |
1572 | of the \f(CW\*(C`SIGxxx\*(C'\fR constants). |
1592 | of the \f(CW\*(C`SIGxxx\*(C'\fR constants). |
1573 | .IP "int signum [read\-only]" 4 |
1593 | .IP "int signum [read\-only]" 4 |
1574 | .IX Item "int signum [read-only]" |
1594 | .IX Item "int signum [read-only]" |
1575 | The signal the watcher watches out for. |
1595 | The signal the watcher watches out for. |
|
|
1596 | .PP |
|
|
1597 | \fIExamples\fR |
|
|
1598 | .IX Subsection "Examples" |
|
|
1599 | .PP |
|
|
1600 | Example: Try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0. |
|
|
1601 | .PP |
|
|
1602 | .Vb 5 |
|
|
1603 | \& static void |
|
|
1604 | \& sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
|
|
1605 | \& { |
|
|
1606 | \& ev_unloop (loop, EVUNLOOP_ALL); |
|
|
1607 | \& } |
|
|
1608 | \& |
|
|
1609 | \& struct ev_signal signal_watcher; |
|
|
1610 | \& ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
|
|
1611 | \& ev_signal_start (loop, &sigint_cb); |
|
|
1612 | .Ve |
1576 | .ie n .Sh """ev_child"" \- watch out for process status changes" |
1613 | .ie n .Sh """ev_child"" \- watch out for process status changes" |
1577 | .el .Sh "\f(CWev_child\fP \- watch out for process status changes" |
1614 | .el .Sh "\f(CWev_child\fP \- watch out for process status changes" |
1578 | .IX Subsection "ev_child - watch out for process status changes" |
1615 | .IX Subsection "ev_child - watch out for process status changes" |
1579 | Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to |
1616 | Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to |
1580 | some child status changes (most typically when a child of yours dies). |
1617 | some child status changes (most typically when a child of yours dies). It |
|
|
1618 | is permissible to install a child watcher \fIafter\fR the child has been |
|
|
1619 | forked (which implies it might have already exited), as long as the event |
|
|
1620 | loop isn't entered (or is continued from a watcher). |
|
|
1621 | .PP |
|
|
1622 | Only the default event loop is capable of handling signals, and therefore |
|
|
1623 | you can only rgeister child watchers in the default event loop. |
|
|
1624 | .PP |
|
|
1625 | \fIProcess Interaction\fR |
|
|
1626 | .IX Subsection "Process Interaction" |
|
|
1627 | .PP |
|
|
1628 | Libev grabs \f(CW\*(C`SIGCHLD\*(C'\fR as soon as the default event loop is |
|
|
1629 | initialised. This is necessary to guarantee proper behaviour even if |
|
|
1630 | the first child watcher is started after the child exits. The occurance |
|
|
1631 | of \f(CW\*(C`SIGCHLD\*(C'\fR is recorded asynchronously, but child reaping is done |
|
|
1632 | synchronously as part of the event loop processing. Libev always reaps all |
|
|
1633 | children, even ones not watched. |
|
|
1634 | .PP |
|
|
1635 | \fIOverriding the Built-In Processing\fR |
|
|
1636 | .IX Subsection "Overriding the Built-In Processing" |
|
|
1637 | .PP |
|
|
1638 | Libev offers no special support for overriding the built-in child |
|
|
1639 | processing, but if your application collides with libev's default child |
|
|
1640 | handler, you can override it easily by installing your own handler for |
|
|
1641 | \&\f(CW\*(C`SIGCHLD\*(C'\fR after initialising the default loop, and making sure the |
|
|
1642 | default loop never gets destroyed. You are encouraged, however, to use an |
|
|
1643 | event-based approach to child reaping and thus use libev's support for |
|
|
1644 | that, so other libev users can use \f(CW\*(C`ev_child\*(C'\fR watchers freely. |
1581 | .PP |
1645 | .PP |
1582 | \fIWatcher-Specific Functions and Data Members\fR |
1646 | \fIWatcher-Specific Functions and Data Members\fR |
1583 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1647 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1584 | .IP "ev_child_init (ev_child *, callback, int pid)" 4 |
1648 | .IP "ev_child_init (ev_child *, callback, int pid, int trace)" 4 |
1585 | .IX Item "ev_child_init (ev_child *, callback, int pid)" |
1649 | .IX Item "ev_child_init (ev_child *, callback, int pid, int trace)" |
1586 | .PD 0 |
1650 | .PD 0 |
1587 | .IP "ev_child_set (ev_child *, int pid)" 4 |
1651 | .IP "ev_child_set (ev_child *, int pid, int trace)" 4 |
1588 | .IX Item "ev_child_set (ev_child *, int pid)" |
1652 | .IX Item "ev_child_set (ev_child *, int pid, int trace)" |
1589 | .PD |
1653 | .PD |
1590 | Configures the watcher to wait for status changes of process \f(CW\*(C`pid\*(C'\fR (or |
1654 | Configures the watcher to wait for status changes of process \f(CW\*(C`pid\*(C'\fR (or |
1591 | \&\fIany\fR process if \f(CW\*(C`pid\*(C'\fR is specified as \f(CW0\fR). The callback can look |
1655 | \&\fIany\fR process if \f(CW\*(C`pid\*(C'\fR is specified as \f(CW0\fR). The callback can look |
1592 | at the \f(CW\*(C`rstatus\*(C'\fR member of the \f(CW\*(C`ev_child\*(C'\fR watcher structure to see |
1656 | at the \f(CW\*(C`rstatus\*(C'\fR member of the \f(CW\*(C`ev_child\*(C'\fR watcher structure to see |
1593 | the status word (use the macros from \f(CW\*(C`sys/wait.h\*(C'\fR and see your systems |
1657 | the status word (use the macros from \f(CW\*(C`sys/wait.h\*(C'\fR and see your systems |
1594 | \&\f(CW\*(C`waitpid\*(C'\fR documentation). The \f(CW\*(C`rpid\*(C'\fR member contains the pid of the |
1658 | \&\f(CW\*(C`waitpid\*(C'\fR documentation). The \f(CW\*(C`rpid\*(C'\fR member contains the pid of the |
1595 | process causing the status change. |
1659 | process causing the status change. \f(CW\*(C`trace\*(C'\fR must be either \f(CW0\fR (only |
|
|
1660 | activate the watcher when the process terminates) or \f(CW1\fR (additionally |
|
|
1661 | activate the watcher when the process is stopped or continued). |
1596 | .IP "int pid [read\-only]" 4 |
1662 | .IP "int pid [read\-only]" 4 |
1597 | .IX Item "int pid [read-only]" |
1663 | .IX Item "int pid [read-only]" |
1598 | The process id this watcher watches out for, or \f(CW0\fR, meaning any process id. |
1664 | The process id this watcher watches out for, or \f(CW0\fR, meaning any process id. |
1599 | .IP "int rpid [read\-write]" 4 |
1665 | .IP "int rpid [read\-write]" 4 |
1600 | .IX Item "int rpid [read-write]" |
1666 | .IX Item "int rpid [read-write]" |
… | |
… | |
1602 | .IP "int rstatus [read\-write]" 4 |
1668 | .IP "int rstatus [read\-write]" 4 |
1603 | .IX Item "int rstatus [read-write]" |
1669 | .IX Item "int rstatus [read-write]" |
1604 | The process exit/trace status caused by \f(CW\*(C`rpid\*(C'\fR (see your systems |
1670 | The process exit/trace status caused by \f(CW\*(C`rpid\*(C'\fR (see your systems |
1605 | \&\f(CW\*(C`waitpid\*(C'\fR and \f(CW\*(C`sys/wait.h\*(C'\fR documentation for details). |
1671 | \&\f(CW\*(C`waitpid\*(C'\fR and \f(CW\*(C`sys/wait.h\*(C'\fR documentation for details). |
1606 | .PP |
1672 | .PP |
1607 | Example: Try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0. |
1673 | \fIExamples\fR |
|
|
1674 | .IX Subsection "Examples" |
1608 | .PP |
1675 | .PP |
|
|
1676 | Example: \f(CW\*(C`fork()\*(C'\fR a new process and install a child handler to wait for |
|
|
1677 | its completion. |
|
|
1678 | .PP |
1609 | .Vb 5 |
1679 | .Vb 1 |
|
|
1680 | \& ev_child cw; |
|
|
1681 | \& |
1610 | \& static void |
1682 | \& static void |
1611 | \& sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
1683 | \& child_cb (EV_P_ struct ev_child *w, int revents) |
1612 | \& { |
1684 | \& { |
1613 | \& ev_unloop (loop, EVUNLOOP_ALL); |
1685 | \& ev_child_stop (EV_A_ w); |
|
|
1686 | \& printf ("process %d exited with status %x\en", w\->rpid, w\->rstatus); |
1614 | \& } |
1687 | \& } |
1615 | .Ve |
1688 | \& |
1616 | .PP |
1689 | \& pid_t pid = fork (); |
1617 | .Vb 3 |
1690 | \& |
1618 | \& struct ev_signal signal_watcher; |
1691 | \& if (pid < 0) |
1619 | \& ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
1692 | \& // error |
1620 | \& ev_signal_start (loop, &sigint_cb); |
1693 | \& else if (pid == 0) |
|
|
1694 | \& { |
|
|
1695 | \& // the forked child executes here |
|
|
1696 | \& exit (1); |
|
|
1697 | \& } |
|
|
1698 | \& else |
|
|
1699 | \& { |
|
|
1700 | \& ev_child_init (&cw, child_cb, pid, 0); |
|
|
1701 | \& ev_child_start (EV_DEFAULT_ &cw); |
|
|
1702 | \& } |
1621 | .Ve |
1703 | .Ve |
1622 | .ie n .Sh """ev_stat"" \- did the file attributes just change?" |
1704 | .ie n .Sh """ev_stat"" \- did the file attributes just change?" |
1623 | .el .Sh "\f(CWev_stat\fP \- did the file attributes just change?" |
1705 | .el .Sh "\f(CWev_stat\fP \- did the file attributes just change?" |
1624 | .IX Subsection "ev_stat - did the file attributes just change?" |
1706 | .IX Subsection "ev_stat - did the file attributes just change?" |
1625 | This watches a filesystem path for attribute changes. That is, it calls |
1707 | This watches a filesystem path for attribute changes. That is, it calls |
… | |
… | |
1644 | impose a minimum interval which is currently around \f(CW0.1\fR, but thats |
1726 | impose a minimum interval which is currently around \f(CW0.1\fR, but thats |
1645 | usually overkill. |
1727 | usually overkill. |
1646 | .PP |
1728 | .PP |
1647 | This watcher type is not meant for massive numbers of stat watchers, |
1729 | This watcher type is not meant for massive numbers of stat watchers, |
1648 | as even with OS-supported change notifications, this can be |
1730 | as even with OS-supported change notifications, this can be |
1649 | resource\-intensive. |
1731 | resource-intensive. |
1650 | .PP |
1732 | .PP |
1651 | At the time of this writing, only the Linux inotify interface is |
1733 | At the time of this writing, only the Linux inotify interface is |
1652 | implemented (implementing kqueue support is left as an exercise for the |
1734 | implemented (implementing kqueue support is left as an exercise for the |
1653 | reader). Inotify will be used to give hints only and should not change the |
1735 | reader). Inotify will be used to give hints only and should not change the |
1654 | semantics of \f(CW\*(C`ev_stat\*(C'\fR watchers, which means that libev sometimes needs |
1736 | semantics of \f(CW\*(C`ev_stat\*(C'\fR watchers, which means that libev sometimes needs |
… | |
… | |
1706 | path for as long as the watcher is active. |
1788 | path for as long as the watcher is active. |
1707 | .Sp |
1789 | .Sp |
1708 | The callback will be receive \f(CW\*(C`EV_STAT\*(C'\fR when a change was detected, |
1790 | The callback will be receive \f(CW\*(C`EV_STAT\*(C'\fR when a change was detected, |
1709 | relative to the attributes at the time the watcher was started (or the |
1791 | relative to the attributes at the time the watcher was started (or the |
1710 | last change was detected). |
1792 | last change was detected). |
1711 | .IP "ev_stat_stat (ev_stat *)" 4 |
1793 | .IP "ev_stat_stat (loop, ev_stat *)" 4 |
1712 | .IX Item "ev_stat_stat (ev_stat *)" |
1794 | .IX Item "ev_stat_stat (loop, ev_stat *)" |
1713 | Updates the stat buffer immediately with new values. If you change the |
1795 | Updates the stat buffer immediately with new values. If you change the |
1714 | watched path in your callback, you could call this fucntion to avoid |
1796 | watched path in your callback, you could call this fucntion to avoid |
1715 | detecting this change (while introducing a race condition). Can also be |
1797 | detecting this change (while introducing a race condition). Can also be |
1716 | useful simply to find out the new values. |
1798 | useful simply to find out the new values. |
1717 | .IP "ev_statdata attr [read\-only]" 4 |
1799 | .IP "ev_statdata attr [read\-only]" 4 |
… | |
… | |
1734 | \fIExamples\fR |
1816 | \fIExamples\fR |
1735 | .IX Subsection "Examples" |
1817 | .IX Subsection "Examples" |
1736 | .PP |
1818 | .PP |
1737 | Example: Watch \f(CW\*(C`/etc/passwd\*(C'\fR for attribute changes. |
1819 | Example: Watch \f(CW\*(C`/etc/passwd\*(C'\fR for attribute changes. |
1738 | .PP |
1820 | .PP |
1739 | .Vb 15 |
1821 | .Vb 10 |
1740 | \& static void |
1822 | \& static void |
1741 | \& passwd_cb (struct ev_loop *loop, ev_stat *w, int revents) |
1823 | \& passwd_cb (struct ev_loop *loop, ev_stat *w, int revents) |
1742 | \& { |
1824 | \& { |
1743 | \& /* /etc/passwd changed in some way */ |
1825 | \& /* /etc/passwd changed in some way */ |
1744 | \& if (w->attr.st_nlink) |
1826 | \& if (w\->attr.st_nlink) |
1745 | \& { |
1827 | \& { |
1746 | \& printf ("passwd current size %ld\en", (long)w->attr.st_size); |
1828 | \& printf ("passwd current size %ld\en", (long)w\->attr.st_size); |
1747 | \& printf ("passwd current atime %ld\en", (long)w->attr.st_mtime); |
1829 | \& printf ("passwd current atime %ld\en", (long)w\->attr.st_mtime); |
1748 | \& printf ("passwd current mtime %ld\en", (long)w->attr.st_mtime); |
1830 | \& printf ("passwd current mtime %ld\en", (long)w\->attr.st_mtime); |
1749 | \& } |
1831 | \& } |
1750 | \& else |
1832 | \& else |
1751 | \& /* you shalt not abuse printf for puts */ |
1833 | \& /* you shalt not abuse printf for puts */ |
1752 | \& puts ("wow, /etc/passwd is not there, expect problems. " |
1834 | \& puts ("wow, /etc/passwd is not there, expect problems. " |
1753 | \& "if this is windows, they already arrived\en"); |
1835 | \& "if this is windows, they already arrived\en"); |
1754 | \& } |
1836 | \& } |
1755 | .Ve |
1837 | \& |
1756 | .PP |
|
|
1757 | .Vb 2 |
|
|
1758 | \& ... |
1838 | \& ... |
1759 | \& ev_stat passwd; |
1839 | \& ev_stat passwd; |
1760 | .Ve |
1840 | \& |
1761 | .PP |
|
|
1762 | .Vb 2 |
|
|
1763 | \& ev_stat_init (&passwd, passwd_cb, "/etc/passwd", 0.); |
1841 | \& ev_stat_init (&passwd, passwd_cb, "/etc/passwd", 0.); |
1764 | \& ev_stat_start (loop, &passwd); |
1842 | \& ev_stat_start (loop, &passwd); |
1765 | .Ve |
1843 | .Ve |
1766 | .PP |
1844 | .PP |
1767 | Example: Like above, but additionally use a one-second delay so we do not |
1845 | Example: Like above, but additionally use a one-second delay so we do not |
… | |
… | |
1770 | \&\f(CW\*(C`ev_timer\*(C'\fR callback invocation). |
1848 | \&\f(CW\*(C`ev_timer\*(C'\fR callback invocation). |
1771 | .PP |
1849 | .PP |
1772 | .Vb 2 |
1850 | .Vb 2 |
1773 | \& static ev_stat passwd; |
1851 | \& static ev_stat passwd; |
1774 | \& static ev_timer timer; |
1852 | \& static ev_timer timer; |
1775 | .Ve |
1853 | \& |
1776 | .PP |
|
|
1777 | .Vb 4 |
|
|
1778 | \& static void |
1854 | \& static void |
1779 | \& timer_cb (EV_P_ ev_timer *w, int revents) |
1855 | \& timer_cb (EV_P_ ev_timer *w, int revents) |
1780 | \& { |
1856 | \& { |
1781 | \& ev_timer_stop (EV_A_ w); |
1857 | \& ev_timer_stop (EV_A_ w); |
1782 | .Ve |
1858 | \& |
1783 | .PP |
|
|
1784 | .Vb 2 |
|
|
1785 | \& /* now it's one second after the most recent passwd change */ |
1859 | \& /* now it\*(Aqs one second after the most recent passwd change */ |
1786 | \& } |
1860 | \& } |
1787 | .Ve |
1861 | \& |
1788 | .PP |
|
|
1789 | .Vb 6 |
|
|
1790 | \& static void |
1862 | \& static void |
1791 | \& stat_cb (EV_P_ ev_stat *w, int revents) |
1863 | \& stat_cb (EV_P_ ev_stat *w, int revents) |
1792 | \& { |
1864 | \& { |
1793 | \& /* reset the one-second timer */ |
1865 | \& /* reset the one\-second timer */ |
1794 | \& ev_timer_again (EV_A_ &timer); |
1866 | \& ev_timer_again (EV_A_ &timer); |
1795 | \& } |
1867 | \& } |
1796 | .Ve |
1868 | \& |
1797 | .PP |
|
|
1798 | .Vb 4 |
|
|
1799 | \& ... |
1869 | \& ... |
1800 | \& ev_stat_init (&passwd, stat_cb, "/etc/passwd", 0.); |
1870 | \& ev_stat_init (&passwd, stat_cb, "/etc/passwd", 0.); |
1801 | \& ev_stat_start (loop, &passwd); |
1871 | \& ev_stat_start (loop, &passwd); |
1802 | \& ev_timer_init (&timer, timer_cb, 0., 1.01); |
1872 | \& ev_timer_init (&timer, timer_cb, 0., 1.01); |
1803 | .Ve |
1873 | .Ve |
… | |
… | |
1818 | The most noteworthy effect is that as long as any idle watchers are |
1888 | The most noteworthy effect is that as long as any idle watchers are |
1819 | active, the process will not block when waiting for new events. |
1889 | active, the process will not block when waiting for new events. |
1820 | .PP |
1890 | .PP |
1821 | Apart from keeping your process non-blocking (which is a useful |
1891 | Apart from keeping your process non-blocking (which is a useful |
1822 | effect on its own sometimes), idle watchers are a good place to do |
1892 | effect on its own sometimes), idle watchers are a good place to do |
1823 | \&\*(L"pseudo\-background processing\*(R", or delay processing stuff to after the |
1893 | \&\*(L"pseudo-background processing\*(R", or delay processing stuff to after the |
1824 | event loop has handled all outstanding events. |
1894 | event loop has handled all outstanding events. |
1825 | .PP |
1895 | .PP |
1826 | \fIWatcher-Specific Functions and Data Members\fR |
1896 | \fIWatcher-Specific Functions and Data Members\fR |
1827 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1897 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1828 | .IP "ev_idle_init (ev_signal *, callback)" 4 |
1898 | .IP "ev_idle_init (ev_signal *, callback)" 4 |
1829 | .IX Item "ev_idle_init (ev_signal *, callback)" |
1899 | .IX Item "ev_idle_init (ev_signal *, callback)" |
1830 | Initialises and configures the idle watcher \- it has no parameters of any |
1900 | Initialises and configures the idle watcher \- it has no parameters of any |
1831 | kind. There is a \f(CW\*(C`ev_idle_set\*(C'\fR macro, but using it is utterly pointless, |
1901 | kind. There is a \f(CW\*(C`ev_idle_set\*(C'\fR macro, but using it is utterly pointless, |
1832 | believe me. |
1902 | believe me. |
1833 | .PP |
1903 | .PP |
|
|
1904 | \fIExamples\fR |
|
|
1905 | .IX Subsection "Examples" |
|
|
1906 | .PP |
1834 | Example: Dynamically allocate an \f(CW\*(C`ev_idle\*(C'\fR watcher, start it, and in the |
1907 | Example: Dynamically allocate an \f(CW\*(C`ev_idle\*(C'\fR watcher, start it, and in the |
1835 | callback, free it. Also, use no error checking, as usual. |
1908 | callback, free it. Also, use no error checking, as usual. |
1836 | .PP |
1909 | .PP |
1837 | .Vb 7 |
1910 | .Vb 7 |
1838 | \& static void |
1911 | \& static void |
1839 | \& idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
1912 | \& idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
1840 | \& { |
1913 | \& { |
1841 | \& free (w); |
1914 | \& free (w); |
1842 | \& // now do something you wanted to do when the program has |
1915 | \& // now do something you wanted to do when the program has |
1843 | \& // no longer asnything immediate to do. |
1916 | \& // no longer anything immediate to do. |
1844 | \& } |
1917 | \& } |
1845 | .Ve |
1918 | \& |
1846 | .PP |
|
|
1847 | .Vb 3 |
|
|
1848 | \& struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle)); |
1919 | \& struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle)); |
1849 | \& ev_idle_init (idle_watcher, idle_cb); |
1920 | \& ev_idle_init (idle_watcher, idle_cb); |
1850 | \& ev_idle_start (loop, idle_cb); |
1921 | \& ev_idle_start (loop, idle_cb); |
1851 | .Ve |
1922 | .Ve |
1852 | .ie n .Sh """ev_prepare""\fP and \f(CW""ev_check"" \- customise your event loop!" |
1923 | .ie n .Sh """ev_prepare""\fP and \f(CW""ev_check"" \- customise your event loop!" |
… | |
… | |
1894 | priority, to ensure that they are being run before any other watchers |
1965 | priority, to ensure that they are being run before any other watchers |
1895 | after the poll. Also, \f(CW\*(C`ev_check\*(C'\fR watchers (and \f(CW\*(C`ev_prepare\*(C'\fR watchers, |
1966 | after the poll. Also, \f(CW\*(C`ev_check\*(C'\fR watchers (and \f(CW\*(C`ev_prepare\*(C'\fR watchers, |
1896 | too) should not activate (\*(L"feed\*(R") events into libev. While libev fully |
1967 | too) should not activate (\*(L"feed\*(R") events into libev. While libev fully |
1897 | supports this, they will be called before other \f(CW\*(C`ev_check\*(C'\fR watchers |
1968 | supports this, they will be called before other \f(CW\*(C`ev_check\*(C'\fR watchers |
1898 | did their job. As \f(CW\*(C`ev_check\*(C'\fR watchers are often used to embed other |
1969 | did their job. As \f(CW\*(C`ev_check\*(C'\fR watchers are often used to embed other |
1899 | (non\-libev) event loops those other event loops might be in an unusable |
1970 | (non-libev) event loops those other event loops might be in an unusable |
1900 | state until their \f(CW\*(C`ev_check\*(C'\fR watcher ran (always remind yourself to |
1971 | state until their \f(CW\*(C`ev_check\*(C'\fR watcher ran (always remind yourself to |
1901 | coexist peacefully with others). |
1972 | coexist peacefully with others). |
1902 | .PP |
1973 | .PP |
1903 | \fIWatcher-Specific Functions and Data Members\fR |
1974 | \fIWatcher-Specific Functions and Data Members\fR |
1904 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1975 | .IX Subsection "Watcher-Specific Functions and Data Members" |
… | |
… | |
1910 | .PD |
1981 | .PD |
1911 | Initialises and configures the prepare or check watcher \- they have no |
1982 | Initialises and configures the prepare or check watcher \- they have no |
1912 | parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR |
1983 | parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR |
1913 | macros, but using them is utterly, utterly and completely pointless. |
1984 | macros, but using them is utterly, utterly and completely pointless. |
1914 | .PP |
1985 | .PP |
|
|
1986 | \fIExamples\fR |
|
|
1987 | .IX Subsection "Examples" |
|
|
1988 | .PP |
1915 | There are a number of principal ways to embed other event loops or modules |
1989 | There are a number of principal ways to embed other event loops or modules |
1916 | into libev. Here are some ideas on how to include libadns into libev |
1990 | into libev. Here are some ideas on how to include libadns into libev |
1917 | (there is a Perl module named \f(CW\*(C`EV::ADNS\*(C'\fR that does this, which you could |
1991 | (there is a Perl module named \f(CW\*(C`EV::ADNS\*(C'\fR that does this, which you could |
1918 | use for an actually working example. Another Perl module named \f(CW\*(C`EV::Glib\*(C'\fR |
1992 | use for an actually working example. Another Perl module named \f(CW\*(C`EV::Glib\*(C'\fR |
1919 | embeds a Glib main context into libev, and finally, \f(CW\*(C`Glib::EV\*(C'\fR embeds \s-1EV\s0 |
1993 | embeds a Glib main context into libev, and finally, \f(CW\*(C`Glib::EV\*(C'\fR embeds \s-1EV\s0 |
… | |
… | |
1926 | the callbacks for the IO/timeout watchers might not have been called yet. |
2000 | the callbacks for the IO/timeout watchers might not have been called yet. |
1927 | .PP |
2001 | .PP |
1928 | .Vb 2 |
2002 | .Vb 2 |
1929 | \& static ev_io iow [nfd]; |
2003 | \& static ev_io iow [nfd]; |
1930 | \& static ev_timer tw; |
2004 | \& static ev_timer tw; |
1931 | .Ve |
2005 | \& |
1932 | .PP |
|
|
1933 | .Vb 4 |
|
|
1934 | \& static void |
2006 | \& static void |
1935 | \& io_cb (ev_loop *loop, ev_io *w, int revents) |
2007 | \& io_cb (ev_loop *loop, ev_io *w, int revents) |
1936 | \& { |
2008 | \& { |
1937 | \& } |
2009 | \& } |
1938 | .Ve |
2010 | \& |
1939 | .PP |
|
|
1940 | .Vb 8 |
|
|
1941 | \& // create io watchers for each fd and a timer before blocking |
2011 | \& // create io watchers for each fd and a timer before blocking |
1942 | \& static void |
2012 | \& static void |
1943 | \& adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
2013 | \& adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
1944 | \& { |
2014 | \& { |
1945 | \& int timeout = 3600000; |
2015 | \& int timeout = 3600000; |
1946 | \& struct pollfd fds [nfd]; |
2016 | \& struct pollfd fds [nfd]; |
1947 | \& // actual code will need to loop here and realloc etc. |
2017 | \& // actual code will need to loop here and realloc etc. |
1948 | \& adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
2018 | \& adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
1949 | .Ve |
2019 | \& |
1950 | .PP |
|
|
1951 | .Vb 3 |
|
|
1952 | \& /* the callback is illegal, but won't be called as we stop during check */ |
2020 | \& /* the callback is illegal, but won\*(Aqt be called as we stop during check */ |
1953 | \& ev_timer_init (&tw, 0, timeout * 1e-3); |
2021 | \& ev_timer_init (&tw, 0, timeout * 1e\-3); |
1954 | \& ev_timer_start (loop, &tw); |
2022 | \& ev_timer_start (loop, &tw); |
1955 | .Ve |
2023 | \& |
1956 | .PP |
|
|
1957 | .Vb 6 |
|
|
1958 | \& // create one ev_io per pollfd |
2024 | \& // create one ev_io per pollfd |
1959 | \& for (int i = 0; i < nfd; ++i) |
2025 | \& for (int i = 0; i < nfd; ++i) |
1960 | \& { |
2026 | \& { |
1961 | \& ev_io_init (iow + i, io_cb, fds [i].fd, |
2027 | \& ev_io_init (iow + i, io_cb, fds [i].fd, |
1962 | \& ((fds [i].events & POLLIN ? EV_READ : 0) |
2028 | \& ((fds [i].events & POLLIN ? EV_READ : 0) |
1963 | \& | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
2029 | \& | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
1964 | .Ve |
2030 | \& |
1965 | .PP |
|
|
1966 | .Vb 4 |
|
|
1967 | \& fds [i].revents = 0; |
2031 | \& fds [i].revents = 0; |
1968 | \& ev_io_start (loop, iow + i); |
2032 | \& ev_io_start (loop, iow + i); |
1969 | \& } |
2033 | \& } |
1970 | \& } |
2034 | \& } |
1971 | .Ve |
2035 | \& |
1972 | .PP |
|
|
1973 | .Vb 5 |
|
|
1974 | \& // stop all watchers after blocking |
2036 | \& // stop all watchers after blocking |
1975 | \& static void |
2037 | \& static void |
1976 | \& adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
2038 | \& adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
1977 | \& { |
2039 | \& { |
1978 | \& ev_timer_stop (loop, &tw); |
2040 | \& ev_timer_stop (loop, &tw); |
1979 | .Ve |
2041 | \& |
1980 | .PP |
|
|
1981 | .Vb 8 |
|
|
1982 | \& for (int i = 0; i < nfd; ++i) |
2042 | \& for (int i = 0; i < nfd; ++i) |
1983 | \& { |
2043 | \& { |
1984 | \& // set the relevant poll flags |
2044 | \& // set the relevant poll flags |
1985 | \& // could also call adns_processreadable etc. here |
2045 | \& // could also call adns_processreadable etc. here |
1986 | \& struct pollfd *fd = fds + i; |
2046 | \& struct pollfd *fd = fds + i; |
1987 | \& int revents = ev_clear_pending (iow + i); |
2047 | \& int revents = ev_clear_pending (iow + i); |
1988 | \& if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
2048 | \& if (revents & EV_READ ) fd\->revents |= fd\->events & POLLIN; |
1989 | \& if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
2049 | \& if (revents & EV_WRITE) fd\->revents |= fd\->events & POLLOUT; |
1990 | .Ve |
2050 | \& |
1991 | .PP |
|
|
1992 | .Vb 3 |
|
|
1993 | \& // now stop the watcher |
2051 | \& // now stop the watcher |
1994 | \& ev_io_stop (loop, iow + i); |
2052 | \& ev_io_stop (loop, iow + i); |
1995 | \& } |
2053 | \& } |
1996 | .Ve |
2054 | \& |
1997 | .PP |
|
|
1998 | .Vb 2 |
|
|
1999 | \& adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
2055 | \& adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
2000 | \& } |
2056 | \& } |
2001 | .Ve |
2057 | .Ve |
2002 | .PP |
2058 | .PP |
2003 | Method 2: This would be just like method 1, but you run \f(CW\*(C`adns_afterpoll\*(C'\fR |
2059 | Method 2: This would be just like method 1, but you run \f(CW\*(C`adns_afterpoll\*(C'\fR |
… | |
… | |
2009 | .PP |
2065 | .PP |
2010 | .Vb 5 |
2066 | .Vb 5 |
2011 | \& static void |
2067 | \& static void |
2012 | \& timer_cb (EV_P_ ev_timer *w, int revents) |
2068 | \& timer_cb (EV_P_ ev_timer *w, int revents) |
2013 | \& { |
2069 | \& { |
2014 | \& adns_state ads = (adns_state)w->data; |
2070 | \& adns_state ads = (adns_state)w\->data; |
2015 | \& update_now (EV_A); |
2071 | \& update_now (EV_A); |
2016 | .Ve |
2072 | \& |
2017 | .PP |
|
|
2018 | .Vb 2 |
|
|
2019 | \& adns_processtimeouts (ads, &tv_now); |
2073 | \& adns_processtimeouts (ads, &tv_now); |
2020 | \& } |
2074 | \& } |
2021 | .Ve |
2075 | \& |
2022 | .PP |
|
|
2023 | .Vb 5 |
|
|
2024 | \& static void |
2076 | \& static void |
2025 | \& io_cb (EV_P_ ev_io *w, int revents) |
2077 | \& io_cb (EV_P_ ev_io *w, int revents) |
2026 | \& { |
2078 | \& { |
2027 | \& adns_state ads = (adns_state)w->data; |
2079 | \& adns_state ads = (adns_state)w\->data; |
2028 | \& update_now (EV_A); |
2080 | \& update_now (EV_A); |
2029 | .Ve |
2081 | \& |
2030 | .PP |
|
|
2031 | .Vb 3 |
|
|
2032 | \& if (revents & EV_READ ) adns_processreadable (ads, w->fd, &tv_now); |
2082 | \& if (revents & EV_READ ) adns_processreadable (ads, w\->fd, &tv_now); |
2033 | \& if (revents & EV_WRITE) adns_processwriteable (ads, w->fd, &tv_now); |
2083 | \& if (revents & EV_WRITE) adns_processwriteable (ads, w\->fd, &tv_now); |
2034 | \& } |
2084 | \& } |
2035 | .Ve |
2085 | \& |
2036 | .PP |
|
|
2037 | .Vb 1 |
|
|
2038 | \& // do not ever call adns_afterpoll |
2086 | \& // do not ever call adns_afterpoll |
2039 | .Ve |
2087 | .Ve |
2040 | .PP |
2088 | .PP |
2041 | Method 4: Do not use a prepare or check watcher because the module you |
2089 | Method 4: Do not use a prepare or check watcher because the module you |
2042 | want to embed is too inflexible to support it. Instead, youc na override |
2090 | want to embed is too inflexible to support it. Instead, youc na override |
… | |
… | |
2047 | .Vb 4 |
2095 | .Vb 4 |
2048 | \& static gint |
2096 | \& static gint |
2049 | \& event_poll_func (GPollFD *fds, guint nfds, gint timeout) |
2097 | \& event_poll_func (GPollFD *fds, guint nfds, gint timeout) |
2050 | \& { |
2098 | \& { |
2051 | \& int got_events = 0; |
2099 | \& int got_events = 0; |
2052 | .Ve |
2100 | \& |
2053 | .PP |
|
|
2054 | .Vb 2 |
|
|
2055 | \& for (n = 0; n < nfds; ++n) |
2101 | \& for (n = 0; n < nfds; ++n) |
2056 | \& // create/start io watcher that sets the relevant bits in fds[n] and increment got_events |
2102 | \& // create/start io watcher that sets the relevant bits in fds[n] and increment got_events |
2057 | .Ve |
2103 | \& |
2058 | .PP |
|
|
2059 | .Vb 2 |
|
|
2060 | \& if (timeout >= 0) |
2104 | \& if (timeout >= 0) |
2061 | \& // create/start timer |
2105 | \& // create/start timer |
2062 | .Ve |
2106 | \& |
2063 | .PP |
|
|
2064 | .Vb 2 |
|
|
2065 | \& // poll |
2107 | \& // poll |
2066 | \& ev_loop (EV_A_ 0); |
2108 | \& ev_loop (EV_A_ 0); |
2067 | .Ve |
2109 | \& |
2068 | .PP |
|
|
2069 | .Vb 3 |
|
|
2070 | \& // stop timer again |
2110 | \& // stop timer again |
2071 | \& if (timeout >= 0) |
2111 | \& if (timeout >= 0) |
2072 | \& ev_timer_stop (EV_A_ &to); |
2112 | \& ev_timer_stop (EV_A_ &to); |
2073 | .Ve |
2113 | \& |
2074 | .PP |
|
|
2075 | .Vb 3 |
|
|
2076 | \& // stop io watchers again - their callbacks should have set |
2114 | \& // stop io watchers again \- their callbacks should have set |
2077 | \& for (n = 0; n < nfds; ++n) |
2115 | \& for (n = 0; n < nfds; ++n) |
2078 | \& ev_io_stop (EV_A_ iow [n]); |
2116 | \& ev_io_stop (EV_A_ iow [n]); |
2079 | .Ve |
2117 | \& |
2080 | .PP |
|
|
2081 | .Vb 2 |
|
|
2082 | \& return got_events; |
2118 | \& return got_events; |
2083 | \& } |
2119 | \& } |
2084 | .Ve |
2120 | .Ve |
2085 | .ie n .Sh """ev_embed"" \- when one backend isn't enough..." |
2121 | .ie n .Sh """ev_embed"" \- when one backend isn't enough..." |
2086 | .el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..." |
2122 | .el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..." |
… | |
… | |
2130 | portable one. |
2166 | portable one. |
2131 | .PP |
2167 | .PP |
2132 | So when you want to use this feature you will always have to be prepared |
2168 | So when you want to use this feature you will always have to be prepared |
2133 | that you cannot get an embeddable loop. The recommended way to get around |
2169 | that you cannot get an embeddable loop. The recommended way to get around |
2134 | this is to have a separate variables for your embeddable loop, try to |
2170 | this is to have a separate variables for your embeddable loop, try to |
2135 | create it, and if that fails, use the normal loop for everything: |
2171 | create it, and if that fails, use the normal loop for everything. |
2136 | .PP |
|
|
2137 | .Vb 3 |
|
|
2138 | \& struct ev_loop *loop_hi = ev_default_init (0); |
|
|
2139 | \& struct ev_loop *loop_lo = 0; |
|
|
2140 | \& struct ev_embed embed; |
|
|
2141 | .Ve |
|
|
2142 | .PP |
|
|
2143 | .Vb 5 |
|
|
2144 | \& // see if there is a chance of getting one that works |
|
|
2145 | \& // (remember that a flags value of 0 means autodetection) |
|
|
2146 | \& loop_lo = ev_embeddable_backends () & ev_recommended_backends () |
|
|
2147 | \& ? ev_loop_new (ev_embeddable_backends () & ev_recommended_backends ()) |
|
|
2148 | \& : 0; |
|
|
2149 | .Ve |
|
|
2150 | .PP |
|
|
2151 | .Vb 8 |
|
|
2152 | \& // if we got one, then embed it, otherwise default to loop_hi |
|
|
2153 | \& if (loop_lo) |
|
|
2154 | \& { |
|
|
2155 | \& ev_embed_init (&embed, 0, loop_lo); |
|
|
2156 | \& ev_embed_start (loop_hi, &embed); |
|
|
2157 | \& } |
|
|
2158 | \& else |
|
|
2159 | \& loop_lo = loop_hi; |
|
|
2160 | .Ve |
|
|
2161 | .PP |
2172 | .PP |
2162 | \fIWatcher-Specific Functions and Data Members\fR |
2173 | \fIWatcher-Specific Functions and Data Members\fR |
2163 | .IX Subsection "Watcher-Specific Functions and Data Members" |
2174 | .IX Subsection "Watcher-Specific Functions and Data Members" |
2164 | .IP "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
2175 | .IP "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
2165 | .IX Item "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" |
2176 | .IX Item "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" |
… | |
… | |
2178 | similarly to \f(CW\*(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\*(C'\fR, but in the most |
2189 | similarly to \f(CW\*(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\*(C'\fR, but in the most |
2179 | apropriate way for embedded loops. |
2190 | apropriate way for embedded loops. |
2180 | .IP "struct ev_loop *other [read\-only]" 4 |
2191 | .IP "struct ev_loop *other [read\-only]" 4 |
2181 | .IX Item "struct ev_loop *other [read-only]" |
2192 | .IX Item "struct ev_loop *other [read-only]" |
2182 | The embedded event loop. |
2193 | The embedded event loop. |
|
|
2194 | .PP |
|
|
2195 | \fIExamples\fR |
|
|
2196 | .IX Subsection "Examples" |
|
|
2197 | .PP |
|
|
2198 | Example: Try to get an embeddable event loop and embed it into the default |
|
|
2199 | event loop. If that is not possible, use the default loop. The default |
|
|
2200 | loop is stored in \f(CW\*(C`loop_hi\*(C'\fR, while the mebeddable loop is stored in |
|
|
2201 | \&\f(CW\*(C`loop_lo\*(C'\fR (which is \f(CW\*(C`loop_hi\*(C'\fR in the acse no embeddable loop can be |
|
|
2202 | used). |
|
|
2203 | .PP |
|
|
2204 | .Vb 3 |
|
|
2205 | \& struct ev_loop *loop_hi = ev_default_init (0); |
|
|
2206 | \& struct ev_loop *loop_lo = 0; |
|
|
2207 | \& struct ev_embed embed; |
|
|
2208 | \& |
|
|
2209 | \& // see if there is a chance of getting one that works |
|
|
2210 | \& // (remember that a flags value of 0 means autodetection) |
|
|
2211 | \& loop_lo = ev_embeddable_backends () & ev_recommended_backends () |
|
|
2212 | \& ? ev_loop_new (ev_embeddable_backends () & ev_recommended_backends ()) |
|
|
2213 | \& : 0; |
|
|
2214 | \& |
|
|
2215 | \& // if we got one, then embed it, otherwise default to loop_hi |
|
|
2216 | \& if (loop_lo) |
|
|
2217 | \& { |
|
|
2218 | \& ev_embed_init (&embed, 0, loop_lo); |
|
|
2219 | \& ev_embed_start (loop_hi, &embed); |
|
|
2220 | \& } |
|
|
2221 | \& else |
|
|
2222 | \& loop_lo = loop_hi; |
|
|
2223 | .Ve |
|
|
2224 | .PP |
|
|
2225 | Example: Check if kqueue is available but not recommended and create |
|
|
2226 | a kqueue backend for use with sockets (which usually work with any |
|
|
2227 | kqueue implementation). Store the kqueue/socket\-only event loop in |
|
|
2228 | \&\f(CW\*(C`loop_socket\*(C'\fR. (One might optionally use \f(CW\*(C`EVFLAG_NOENV\*(C'\fR, too). |
|
|
2229 | .PP |
|
|
2230 | .Vb 3 |
|
|
2231 | \& struct ev_loop *loop = ev_default_init (0); |
|
|
2232 | \& struct ev_loop *loop_socket = 0; |
|
|
2233 | \& struct ev_embed embed; |
|
|
2234 | \& |
|
|
2235 | \& if (ev_supported_backends () & ~ev_recommended_backends () & EVBACKEND_KQUEUE) |
|
|
2236 | \& if ((loop_socket = ev_loop_new (EVBACKEND_KQUEUE)) |
|
|
2237 | \& { |
|
|
2238 | \& ev_embed_init (&embed, 0, loop_socket); |
|
|
2239 | \& ev_embed_start (loop, &embed); |
|
|
2240 | \& } |
|
|
2241 | \& |
|
|
2242 | \& if (!loop_socket) |
|
|
2243 | \& loop_socket = loop; |
|
|
2244 | \& |
|
|
2245 | \& // now use loop_socket for all sockets, and loop for everything else |
|
|
2246 | .Ve |
2183 | .ie n .Sh """ev_fork"" \- the audacity to resume the event loop after a fork" |
2247 | .ie n .Sh """ev_fork"" \- the audacity to resume the event loop after a fork" |
2184 | .el .Sh "\f(CWev_fork\fP \- the audacity to resume the event loop after a fork" |
2248 | .el .Sh "\f(CWev_fork\fP \- the audacity to resume the event loop after a fork" |
2185 | .IX Subsection "ev_fork - the audacity to resume the event loop after a fork" |
2249 | .IX Subsection "ev_fork - the audacity to resume the event loop after a fork" |
2186 | Fork watchers are called when a \f(CW\*(C`fork ()\*(C'\fR was detected (usually because |
2250 | Fork watchers are called when a \f(CW\*(C`fork ()\*(C'\fR was detected (usually because |
2187 | whoever is a good citizen cared to tell libev about it by calling |
2251 | whoever is a good citizen cared to tell libev about it by calling |
… | |
… | |
2196 | .IP "ev_fork_init (ev_signal *, callback)" 4 |
2260 | .IP "ev_fork_init (ev_signal *, callback)" 4 |
2197 | .IX Item "ev_fork_init (ev_signal *, callback)" |
2261 | .IX Item "ev_fork_init (ev_signal *, callback)" |
2198 | Initialises and configures the fork watcher \- it has no parameters of any |
2262 | Initialises and configures the fork watcher \- it has no parameters of any |
2199 | kind. There is a \f(CW\*(C`ev_fork_set\*(C'\fR macro, but using it is utterly pointless, |
2263 | kind. There is a \f(CW\*(C`ev_fork_set\*(C'\fR macro, but using it is utterly pointless, |
2200 | believe me. |
2264 | believe me. |
|
|
2265 | .ie n .Sh """ev_async"" \- how to wake up another event loop" |
|
|
2266 | .el .Sh "\f(CWev_async\fP \- how to wake up another event loop" |
|
|
2267 | .IX Subsection "ev_async - how to wake up another event loop" |
|
|
2268 | In general, you cannot use an \f(CW\*(C`ev_loop\*(C'\fR from multiple threads or other |
|
|
2269 | asynchronous sources such as signal handlers (as opposed to multiple event |
|
|
2270 | loops \- those are of course safe to use in different threads). |
|
|
2271 | .PP |
|
|
2272 | Sometimes, however, you need to wake up another event loop you do not |
|
|
2273 | control, for example because it belongs to another thread. This is what |
|
|
2274 | \&\f(CW\*(C`ev_async\*(C'\fR watchers do: as long as the \f(CW\*(C`ev_async\*(C'\fR watcher is active, you |
|
|
2275 | can signal it by calling \f(CW\*(C`ev_async_send\*(C'\fR, which is thread\- and signal |
|
|
2276 | safe. |
|
|
2277 | .PP |
|
|
2278 | This functionality is very similar to \f(CW\*(C`ev_signal\*(C'\fR watchers, as signals, |
|
|
2279 | too, are asynchronous in nature, and signals, too, will be compressed |
|
|
2280 | (i.e. the number of callback invocations may be less than the number of |
|
|
2281 | \&\f(CW\*(C`ev_async_sent\*(C'\fR calls). |
|
|
2282 | .PP |
|
|
2283 | Unlike \f(CW\*(C`ev_signal\*(C'\fR watchers, \f(CW\*(C`ev_async\*(C'\fR works with any event loop, not |
|
|
2284 | just the default loop. |
|
|
2285 | .PP |
|
|
2286 | \fIQueueing\fR |
|
|
2287 | .IX Subsection "Queueing" |
|
|
2288 | .PP |
|
|
2289 | \&\f(CW\*(C`ev_async\*(C'\fR does not support queueing of data in any way. The reason |
|
|
2290 | is that the author does not know of a simple (or any) algorithm for a |
|
|
2291 | multiple-writer-single-reader queue that works in all cases and doesn't |
|
|
2292 | need elaborate support such as pthreads. |
|
|
2293 | .PP |
|
|
2294 | That means that if you want to queue data, you have to provide your own |
|
|
2295 | queue. But at least I can tell you would implement locking around your |
|
|
2296 | queue: |
|
|
2297 | .IP "queueing from a signal handler context" 4 |
|
|
2298 | .IX Item "queueing from a signal handler context" |
|
|
2299 | To implement race-free queueing, you simply add to the queue in the signal |
|
|
2300 | handler but you block the signal handler in the watcher callback. Here is an example that does that for |
|
|
2301 | some fictitiuous \s-1SIGUSR1\s0 handler: |
|
|
2302 | .Sp |
|
|
2303 | .Vb 1 |
|
|
2304 | \& static ev_async mysig; |
|
|
2305 | \& |
|
|
2306 | \& static void |
|
|
2307 | \& sigusr1_handler (void) |
|
|
2308 | \& { |
|
|
2309 | \& sometype data; |
|
|
2310 | \& |
|
|
2311 | \& // no locking etc. |
|
|
2312 | \& queue_put (data); |
|
|
2313 | \& ev_async_send (EV_DEFAULT_ &mysig); |
|
|
2314 | \& } |
|
|
2315 | \& |
|
|
2316 | \& static void |
|
|
2317 | \& mysig_cb (EV_P_ ev_async *w, int revents) |
|
|
2318 | \& { |
|
|
2319 | \& sometype data; |
|
|
2320 | \& sigset_t block, prev; |
|
|
2321 | \& |
|
|
2322 | \& sigemptyset (&block); |
|
|
2323 | \& sigaddset (&block, SIGUSR1); |
|
|
2324 | \& sigprocmask (SIG_BLOCK, &block, &prev); |
|
|
2325 | \& |
|
|
2326 | \& while (queue_get (&data)) |
|
|
2327 | \& process (data); |
|
|
2328 | \& |
|
|
2329 | \& if (sigismember (&prev, SIGUSR1) |
|
|
2330 | \& sigprocmask (SIG_UNBLOCK, &block, 0); |
|
|
2331 | \& } |
|
|
2332 | .Ve |
|
|
2333 | .Sp |
|
|
2334 | (Note: pthreads in theory requires you to use \f(CW\*(C`pthread_setmask\*(C'\fR |
|
|
2335 | instead of \f(CW\*(C`sigprocmask\*(C'\fR when you use threads, but libev doesn't do it |
|
|
2336 | either...). |
|
|
2337 | .IP "queueing from a thread context" 4 |
|
|
2338 | .IX Item "queueing from a thread context" |
|
|
2339 | The strategy for threads is different, as you cannot (easily) block |
|
|
2340 | threads but you can easily preempt them, so to queue safely you need to |
|
|
2341 | employ a traditional mutex lock, such as in this pthread example: |
|
|
2342 | .Sp |
|
|
2343 | .Vb 2 |
|
|
2344 | \& static ev_async mysig; |
|
|
2345 | \& static pthread_mutex_t mymutex = PTHREAD_MUTEX_INITIALIZER; |
|
|
2346 | \& |
|
|
2347 | \& static void |
|
|
2348 | \& otherthread (void) |
|
|
2349 | \& { |
|
|
2350 | \& // only need to lock the actual queueing operation |
|
|
2351 | \& pthread_mutex_lock (&mymutex); |
|
|
2352 | \& queue_put (data); |
|
|
2353 | \& pthread_mutex_unlock (&mymutex); |
|
|
2354 | \& |
|
|
2355 | \& ev_async_send (EV_DEFAULT_ &mysig); |
|
|
2356 | \& } |
|
|
2357 | \& |
|
|
2358 | \& static void |
|
|
2359 | \& mysig_cb (EV_P_ ev_async *w, int revents) |
|
|
2360 | \& { |
|
|
2361 | \& pthread_mutex_lock (&mymutex); |
|
|
2362 | \& |
|
|
2363 | \& while (queue_get (&data)) |
|
|
2364 | \& process (data); |
|
|
2365 | \& |
|
|
2366 | \& pthread_mutex_unlock (&mymutex); |
|
|
2367 | \& } |
|
|
2368 | .Ve |
|
|
2369 | .PP |
|
|
2370 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
2371 | .IX Subsection "Watcher-Specific Functions and Data Members" |
|
|
2372 | .IP "ev_async_init (ev_async *, callback)" 4 |
|
|
2373 | .IX Item "ev_async_init (ev_async *, callback)" |
|
|
2374 | Initialises and configures the async watcher \- it has no parameters of any |
|
|
2375 | kind. There is a \f(CW\*(C`ev_asynd_set\*(C'\fR macro, but using it is utterly pointless, |
|
|
2376 | believe me. |
|
|
2377 | .IP "ev_async_send (loop, ev_async *)" 4 |
|
|
2378 | .IX Item "ev_async_send (loop, ev_async *)" |
|
|
2379 | Sends/signals/activates the given \f(CW\*(C`ev_async\*(C'\fR watcher, that is, feeds |
|
|
2380 | an \f(CW\*(C`EV_ASYNC\*(C'\fR event on the watcher into the event loop. Unlike |
|
|
2381 | \&\f(CW\*(C`ev_feed_event\*(C'\fR, this call is safe to do in other threads, signal or |
|
|
2382 | similar contexts (see the dicusssion of \f(CW\*(C`EV_ATOMIC_T\*(C'\fR in the embedding |
|
|
2383 | section below on what exactly this means). |
|
|
2384 | .Sp |
|
|
2385 | This call incurs the overhead of a syscall only once per loop iteration, |
|
|
2386 | so while the overhead might be noticable, it doesn't apply to repeated |
|
|
2387 | calls to \f(CW\*(C`ev_async_send\*(C'\fR. |
2201 | .SH "OTHER FUNCTIONS" |
2388 | .SH "OTHER FUNCTIONS" |
2202 | .IX Header "OTHER FUNCTIONS" |
2389 | .IX Header "OTHER FUNCTIONS" |
2203 | There are some other functions of possible interest. Described. Here. Now. |
2390 | There are some other functions of possible interest. Described. Here. Now. |
2204 | .IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4 |
2391 | .IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4 |
2205 | .IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" |
2392 | .IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" |
… | |
… | |
2229 | \& if (revents & EV_TIMEOUT) |
2416 | \& if (revents & EV_TIMEOUT) |
2230 | \& /* doh, nothing entered */; |
2417 | \& /* doh, nothing entered */; |
2231 | \& else if (revents & EV_READ) |
2418 | \& else if (revents & EV_READ) |
2232 | \& /* stdin might have data for us, joy! */; |
2419 | \& /* stdin might have data for us, joy! */; |
2233 | \& } |
2420 | \& } |
2234 | .Ve |
2421 | \& |
2235 | .Sp |
|
|
2236 | .Vb 1 |
|
|
2237 | \& ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0); |
2422 | \& ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0); |
2238 | .Ve |
2423 | .Ve |
2239 | .IP "ev_feed_event (ev_loop *, watcher *, int revents)" 4 |
2424 | .IP "ev_feed_event (ev_loop *, watcher *, int revents)" 4 |
2240 | .IX Item "ev_feed_event (ev_loop *, watcher *, int revents)" |
2425 | .IX Item "ev_feed_event (ev_loop *, watcher *, int revents)" |
2241 | Feeds the given event set into the event loop, as if the specified event |
2426 | Feeds the given event set into the event loop, as if the specified event |
… | |
… | |
2251 | loop!). |
2436 | loop!). |
2252 | .SH "LIBEVENT EMULATION" |
2437 | .SH "LIBEVENT EMULATION" |
2253 | .IX Header "LIBEVENT EMULATION" |
2438 | .IX Header "LIBEVENT EMULATION" |
2254 | Libev offers a compatibility emulation layer for libevent. It cannot |
2439 | Libev offers a compatibility emulation layer for libevent. It cannot |
2255 | emulate the internals of libevent, so here are some usage hints: |
2440 | emulate the internals of libevent, so here are some usage hints: |
|
|
2441 | .IP "\(bu" 4 |
2256 | .IP "* Use it by including <event.h>, as usual." 4 |
2442 | Use it by including <event.h>, as usual. |
2257 | .IX Item "Use it by including <event.h>, as usual." |
2443 | .IP "\(bu" 4 |
2258 | .PD 0 |
2444 | The following members are fully supported: ev_base, ev_callback, |
2259 | .IP "* The following members are fully supported: ev_base, ev_callback, ev_arg, ev_fd, ev_res, ev_events." 4 |
2445 | ev_arg, ev_fd, ev_res, ev_events. |
2260 | .IX Item "The following members are fully supported: ev_base, ev_callback, ev_arg, ev_fd, ev_res, ev_events." |
2446 | .IP "\(bu" 4 |
2261 | .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 |
2447 | Avoid using ev_flags and the EVLIST_*\-macros, while it is |
2262 | .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)." |
2448 | maintained by libev, it does not work exactly the same way as in libevent (consider |
2263 | .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 |
2449 | it a private \s-1API\s0). |
2264 | .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." |
2450 | .IP "\(bu" 4 |
|
|
2451 | Priorities are not currently supported. Initialising priorities |
|
|
2452 | will fail and all watchers will have the same priority, even though there |
|
|
2453 | is an ev_pri field. |
|
|
2454 | .IP "\(bu" 4 |
2265 | .IP "* Other members are not supported." 4 |
2455 | Other members are not supported. |
2266 | .IX Item "Other members are not supported." |
2456 | .IP "\(bu" 4 |
2267 | .IP "* The libev emulation is \fInot\fR \s-1ABI\s0 compatible to libevent, you need to use the libev header file and library." 4 |
2457 | The libev emulation is \fInot\fR \s-1ABI\s0 compatible to libevent, you need |
2268 | .IX Item "The libev emulation is not ABI compatible to libevent, you need to use the libev header file and library." |
2458 | to use the libev header file and library. |
2269 | .PD |
|
|
2270 | .SH "\*(C+ SUPPORT" |
2459 | .SH "\*(C+ SUPPORT" |
2271 | .IX Header " SUPPORT" |
2460 | .IX Header " SUPPORT" |
2272 | Libev comes with some simplistic wrapper classes for \*(C+ that mainly allow |
2461 | Libev comes with some simplistic wrapper classes for \*(C+ that mainly allow |
2273 | you to use some convinience methods to start/stop watchers and also change |
2462 | you to use some convinience methods to start/stop watchers and also change |
2274 | the callback model to a model using method callbacks on objects. |
2463 | the callback model to a model using method callbacks on objects. |
… | |
… | |
2354 | .Vb 4 |
2543 | .Vb 4 |
2355 | \& struct myclass |
2544 | \& struct myclass |
2356 | \& { |
2545 | \& { |
2357 | \& void io_cb (ev::io &w, int revents) { } |
2546 | \& void io_cb (ev::io &w, int revents) { } |
2358 | \& } |
2547 | \& } |
2359 | .Ve |
2548 | \& |
2360 | .Sp |
|
|
2361 | .Vb 3 |
|
|
2362 | \& myclass obj; |
2549 | \& myclass obj; |
2363 | \& ev::io iow; |
2550 | \& ev::io iow; |
2364 | \& iow.set <myclass, &myclass::io_cb> (&obj); |
2551 | \& iow.set <myclass, &myclass::io_cb> (&obj); |
2365 | .Ve |
2552 | .Ve |
2366 | .IP "w\->set<function> (void *data = 0)" 4 |
2553 | .IP "w\->set<function> (void *data = 0)" 4 |
… | |
… | |
2417 | the constructor. |
2604 | the constructor. |
2418 | .PP |
2605 | .PP |
2419 | .Vb 4 |
2606 | .Vb 4 |
2420 | \& class myclass |
2607 | \& class myclass |
2421 | \& { |
2608 | \& { |
2422 | \& ev_io io; void io_cb (ev::io &w, int revents); |
2609 | \& ev::io io; void io_cb (ev::io &w, int revents); |
2423 | \& ev_idle idle void idle_cb (ev::idle &w, int revents); |
2610 | \& ev:idle idle void idle_cb (ev::idle &w, int revents); |
2424 | .Ve |
2611 | \& |
2425 | .PP |
|
|
2426 | .Vb 2 |
|
|
2427 | \& myclass (); |
2612 | \& myclass (int fd) |
2428 | \& } |
|
|
2429 | .Ve |
|
|
2430 | .PP |
|
|
2431 | .Vb 4 |
|
|
2432 | \& myclass::myclass (int fd) |
|
|
2433 | \& { |
2613 | \& { |
2434 | \& io .set <myclass, &myclass::io_cb > (this); |
2614 | \& io .set <myclass, &myclass::io_cb > (this); |
2435 | \& idle.set <myclass, &myclass::idle_cb> (this); |
2615 | \& idle.set <myclass, &myclass::idle_cb> (this); |
2436 | .Ve |
2616 | \& |
2437 | .PP |
|
|
2438 | .Vb 2 |
|
|
2439 | \& io.start (fd, ev::READ); |
2617 | \& io.start (fd, ev::READ); |
|
|
2618 | \& } |
2440 | \& } |
2619 | \& }; |
2441 | .Ve |
2620 | .Ve |
|
|
2621 | .SH "OTHER LANGUAGE BINDINGS" |
|
|
2622 | .IX Header "OTHER LANGUAGE BINDINGS" |
|
|
2623 | Libev does not offer other language bindings itself, but bindings for a |
|
|
2624 | numbe rof languages exist in the form of third-party packages. If you know |
|
|
2625 | any interesting language binding in addition to the ones listed here, drop |
|
|
2626 | me a note. |
|
|
2627 | .IP "Perl" 4 |
|
|
2628 | .IX Item "Perl" |
|
|
2629 | The \s-1EV\s0 module implements the full libev \s-1API\s0 and is actually used to test |
|
|
2630 | libev. \s-1EV\s0 is developed together with libev. Apart from the \s-1EV\s0 core module, |
|
|
2631 | there are additional modules that implement libev-compatible interfaces |
|
|
2632 | to \f(CW\*(C`libadns\*(C'\fR (\f(CW\*(C`EV::ADNS\*(C'\fR), \f(CW\*(C`Net::SNMP\*(C'\fR (\f(CW\*(C`Net::SNMP::EV\*(C'\fR) and the |
|
|
2633 | \&\f(CW\*(C`libglib\*(C'\fR event core (\f(CW\*(C`Glib::EV\*(C'\fR and \f(CW\*(C`EV::Glib\*(C'\fR). |
|
|
2634 | .Sp |
|
|
2635 | It can be found and installed via \s-1CPAN\s0, its homepage is found at |
|
|
2636 | <http://software.schmorp.de/pkg/EV>. |
|
|
2637 | .IP "Ruby" 4 |
|
|
2638 | .IX Item "Ruby" |
|
|
2639 | Tony Arcieri has written a ruby extension that offers access to a subset |
|
|
2640 | of the libev \s-1API\s0 and adds filehandle abstractions, asynchronous \s-1DNS\s0 and |
|
|
2641 | more on top of it. It can be found via gem servers. Its homepage is at |
|
|
2642 | <http://rev.rubyforge.org/>. |
|
|
2643 | .IP "D" 4 |
|
|
2644 | .IX Item "D" |
|
|
2645 | Leandro Lucarella has written a D language binding (\fIev.d\fR) for libev, to |
|
|
2646 | be found at <http://git.llucax.com.ar/?p=software/ev.d.git;a=summary>. |
2442 | .SH "MACRO MAGIC" |
2647 | .SH "MACRO MAGIC" |
2443 | .IX Header "MACRO MAGIC" |
2648 | .IX Header "MACRO MAGIC" |
2444 | Libev can be compiled with a variety of options, the most fundamantal |
2649 | Libev can be compiled with a variety of options, the most fundamantal |
2445 | of which is \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines whether (most) |
2650 | of which is \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines whether (most) |
2446 | functions and callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument. |
2651 | functions and callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument. |
… | |
… | |
2470 | \&\f(CW\*(C`EV_P_\*(C'\fR is used when other parameters are following. Example: |
2675 | \&\f(CW\*(C`EV_P_\*(C'\fR is used when other parameters are following. Example: |
2471 | .Sp |
2676 | .Sp |
2472 | .Vb 2 |
2677 | .Vb 2 |
2473 | \& // this is how ev_unref is being declared |
2678 | \& // this is how ev_unref is being declared |
2474 | \& static void ev_unref (EV_P); |
2679 | \& static void ev_unref (EV_P); |
2475 | .Ve |
2680 | \& |
2476 | .Sp |
|
|
2477 | .Vb 2 |
|
|
2478 | \& // this is how you can declare your typical callback |
2681 | \& // this is how you can declare your typical callback |
2479 | \& static void cb (EV_P_ ev_timer *w, int revents) |
2682 | \& static void cb (EV_P_ ev_timer *w, int revents) |
2480 | .Ve |
2683 | .Ve |
2481 | .Sp |
2684 | .Sp |
2482 | It declares a parameter \f(CW\*(C`loop\*(C'\fR of type \f(CW\*(C`struct ev_loop *\*(C'\fR, quite |
2685 | It declares a parameter \f(CW\*(C`loop\*(C'\fR of type \f(CW\*(C`struct ev_loop *\*(C'\fR, quite |
… | |
… | |
2495 | \& static void |
2698 | \& static void |
2496 | \& check_cb (EV_P_ ev_timer *w, int revents) |
2699 | \& check_cb (EV_P_ ev_timer *w, int revents) |
2497 | \& { |
2700 | \& { |
2498 | \& ev_check_stop (EV_A_ w); |
2701 | \& ev_check_stop (EV_A_ w); |
2499 | \& } |
2702 | \& } |
2500 | .Ve |
2703 | \& |
2501 | .PP |
|
|
2502 | .Vb 4 |
|
|
2503 | \& ev_check check; |
2704 | \& ev_check check; |
2504 | \& ev_check_init (&check, check_cb); |
2705 | \& ev_check_init (&check, check_cb); |
2505 | \& ev_check_start (EV_DEFAULT_ &check); |
2706 | \& ev_check_start (EV_DEFAULT_ &check); |
2506 | \& ev_loop (EV_DEFAULT_ 0); |
2707 | \& ev_loop (EV_DEFAULT_ 0); |
2507 | .Ve |
2708 | .Ve |
2508 | .SH "EMBEDDING" |
2709 | .SH "EMBEDDING" |
2509 | .IX Header "EMBEDDING" |
2710 | .IX Header "EMBEDDING" |
2510 | Libev can (and often is) directly embedded into host |
2711 | Libev can (and often is) directly embedded into host |
2511 | applications. Examples of applications that embed it include the Deliantra |
2712 | applications. Examples of applications that embed it include the Deliantra |
2512 | Game Server, the \s-1EV\s0 perl module, the \s-1GNU\s0 Virtual Private Ethernet (gvpe) |
2713 | Game Server, the \s-1EV\s0 perl module, the \s-1GNU\s0 Virtual Private Ethernet (gvpe) |
2513 | and rxvt\-unicode. |
2714 | and rxvt-unicode. |
2514 | .PP |
2715 | .PP |
2515 | The goal is to enable you to just copy the necessary files into your |
2716 | The goal is to enable you to just copy the necessary files into your |
2516 | source directory without having to change even a single line in them, so |
2717 | source directory without having to change even a single line in them, so |
2517 | you can easily upgrade by simply copying (or having a checked-out copy of |
2718 | you can easily upgrade by simply copying (or having a checked-out copy of |
2518 | libev somewhere in your source tree). |
2719 | libev somewhere in your source tree). |
… | |
… | |
2553 | .Vb 4 |
2754 | .Vb 4 |
2554 | \& ev.h |
2755 | \& ev.h |
2555 | \& ev.c |
2756 | \& ev.c |
2556 | \& ev_vars.h |
2757 | \& ev_vars.h |
2557 | \& ev_wrap.h |
2758 | \& ev_wrap.h |
2558 | .Ve |
2759 | \& |
2559 | .PP |
|
|
2560 | .Vb 1 |
|
|
2561 | \& ev_win32.c required on win32 platforms only |
2760 | \& ev_win32.c required on win32 platforms only |
2562 | .Ve |
2761 | \& |
2563 | .PP |
|
|
2564 | .Vb 5 |
|
|
2565 | \& ev_select.c only when select backend is enabled (which is enabled by default) |
2762 | \& ev_select.c only when select backend is enabled (which is enabled by default) |
2566 | \& ev_poll.c only when poll backend is enabled (disabled by default) |
2763 | \& ev_poll.c only when poll backend is enabled (disabled by default) |
2567 | \& ev_epoll.c only when the epoll backend is enabled (disabled by default) |
2764 | \& ev_epoll.c only when the epoll backend is enabled (disabled by default) |
2568 | \& ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
2765 | \& ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
2569 | \& ev_port.c only when the solaris port backend is enabled (disabled by default) |
2766 | \& ev_port.c only when the solaris port backend is enabled (disabled by default) |
… | |
… | |
2664 | wants osf handles on win32 (this is the case when the select to |
2861 | wants osf handles on win32 (this is the case when the select to |
2665 | be used is the winsock select). This means that it will call |
2862 | be used is the winsock select). This means that it will call |
2666 | \&\f(CW\*(C`_get_osfhandle\*(C'\fR on the fd to convert it to an \s-1OS\s0 handle. Otherwise, |
2863 | \&\f(CW\*(C`_get_osfhandle\*(C'\fR on the fd to convert it to an \s-1OS\s0 handle. Otherwise, |
2667 | it is assumed that all these functions actually work on fds, even |
2864 | it is assumed that all these functions actually work on fds, even |
2668 | on win32. Should not be defined on non\-win32 platforms. |
2865 | on win32. Should not be defined on non\-win32 platforms. |
|
|
2866 | .IP "\s-1EV_FD_TO_WIN32_HANDLE\s0" 4 |
|
|
2867 | .IX Item "EV_FD_TO_WIN32_HANDLE" |
|
|
2868 | If \f(CW\*(C`EV_SELECT_IS_WINSOCKET\*(C'\fR is enabled, then libev needs a way to map |
|
|
2869 | file descriptors to socket handles. When not defining this symbol (the |
|
|
2870 | default), then libev will call \f(CW\*(C`_get_osfhandle\*(C'\fR, which is usually |
|
|
2871 | correct. In some cases, programs use their own file descriptor management, |
|
|
2872 | in which case they can provide this function to map fds to socket handles. |
2669 | .IP "\s-1EV_USE_POLL\s0" 4 |
2873 | .IP "\s-1EV_USE_POLL\s0" 4 |
2670 | .IX Item "EV_USE_POLL" |
2874 | .IX Item "EV_USE_POLL" |
2671 | If defined to be \f(CW1\fR, libev will compile in support for the \f(CW\*(C`poll\*(C'\fR(2) |
2875 | If defined to be \f(CW1\fR, libev will compile in support for the \f(CW\*(C`poll\*(C'\fR(2) |
2672 | backend. Otherwise it will be enabled on non\-win32 platforms. It |
2876 | backend. Otherwise it will be enabled on non\-win32 platforms. It |
2673 | takes precedence over select. |
2877 | takes precedence over select. |
… | |
… | |
2700 | .IP "\s-1EV_USE_INOTIFY\s0" 4 |
2904 | .IP "\s-1EV_USE_INOTIFY\s0" 4 |
2701 | .IX Item "EV_USE_INOTIFY" |
2905 | .IX Item "EV_USE_INOTIFY" |
2702 | If defined to be \f(CW1\fR, libev will compile in support for the Linux inotify |
2906 | If defined to be \f(CW1\fR, libev will compile in support for the Linux inotify |
2703 | interface to speed up \f(CW\*(C`ev_stat\*(C'\fR watchers. Its actual availability will |
2907 | interface to speed up \f(CW\*(C`ev_stat\*(C'\fR watchers. Its actual availability will |
2704 | be detected at runtime. |
2908 | be detected at runtime. |
|
|
2909 | .IP "\s-1EV_ATOMIC_T\s0" 4 |
|
|
2910 | .IX Item "EV_ATOMIC_T" |
|
|
2911 | Libev requires an integer type (suitable for storing \f(CW0\fR or \f(CW1\fR) whose |
|
|
2912 | access is atomic with respect to other threads or signal contexts. No such |
|
|
2913 | type is easily found in the C language, so you can provide your own type |
|
|
2914 | that you know is safe for your purposes. It is used both for signal handler \*(L"locking\*(R" |
|
|
2915 | as well as for signal and thread safety in \f(CW\*(C`ev_async\*(C'\fR watchers. |
|
|
2916 | .Sp |
|
|
2917 | In the absense of this define, libev will use \f(CW\*(C`sig_atomic_t volatile\*(C'\fR |
|
|
2918 | (from \fIsignal.h\fR), which is usually good enough on most platforms. |
2705 | .IP "\s-1EV_H\s0" 4 |
2919 | .IP "\s-1EV_H\s0" 4 |
2706 | .IX Item "EV_H" |
2920 | .IX Item "EV_H" |
2707 | The name of the \fIev.h\fR header file used to include it. The default if |
2921 | The name of the \fIev.h\fR header file used to include it. The default if |
2708 | undefined is \f(CW"ev.h"\fR in \fIevent.h\fR and \fIev.c\fR. This can be used to |
2922 | undefined is \f(CW"ev.h"\fR in \fIevent.h\fR, \fIev.c\fR and \fIev++.h\fR. This can be |
2709 | virtually rename the \fIev.h\fR header file in case of conflicts. |
2923 | used to virtually rename the \fIev.h\fR header file in case of conflicts. |
2710 | .IP "\s-1EV_CONFIG_H\s0" 4 |
2924 | .IP "\s-1EV_CONFIG_H\s0" 4 |
2711 | .IX Item "EV_CONFIG_H" |
2925 | .IX Item "EV_CONFIG_H" |
2712 | If \f(CW\*(C`EV_STANDALONE\*(C'\fR isn't \f(CW1\fR, this variable can be used to override |
2926 | If \f(CW\*(C`EV_STANDALONE\*(C'\fR isn't \f(CW1\fR, this variable can be used to override |
2713 | \&\fIev.c\fR's idea of where to find the \fIconfig.h\fR file, similarly to |
2927 | \&\fIev.c\fR's idea of where to find the \fIconfig.h\fR file, similarly to |
2714 | \&\f(CW\*(C`EV_H\*(C'\fR, above. |
2928 | \&\f(CW\*(C`EV_H\*(C'\fR, above. |
2715 | .IP "\s-1EV_EVENT_H\s0" 4 |
2929 | .IP "\s-1EV_EVENT_H\s0" 4 |
2716 | .IX Item "EV_EVENT_H" |
2930 | .IX Item "EV_EVENT_H" |
2717 | Similarly to \f(CW\*(C`EV_H\*(C'\fR, this macro can be used to override \fIevent.c\fR's idea |
2931 | Similarly to \f(CW\*(C`EV_H\*(C'\fR, this macro can be used to override \fIevent.c\fR's idea |
2718 | of how the \fIevent.h\fR header can be found, the dfeault is \f(CW"event.h"\fR. |
2932 | of how the \fIevent.h\fR header can be found, the default is \f(CW"event.h"\fR. |
2719 | .IP "\s-1EV_PROTOTYPES\s0" 4 |
2933 | .IP "\s-1EV_PROTOTYPES\s0" 4 |
2720 | .IX Item "EV_PROTOTYPES" |
2934 | .IX Item "EV_PROTOTYPES" |
2721 | If defined to be \f(CW0\fR, then \fIev.h\fR will not define any function |
2935 | If defined to be \f(CW0\fR, then \fIev.h\fR will not define any function |
2722 | prototypes, but still define all the structs and other symbols. This is |
2936 | prototypes, but still define all the structs and other symbols. This is |
2723 | occasionally useful if you want to provide your own wrapper functions |
2937 | occasionally useful if you want to provide your own wrapper functions |
… | |
… | |
2766 | If undefined or defined to be \f(CW1\fR, then stat watchers are supported. If |
2980 | If undefined or defined to be \f(CW1\fR, then stat watchers are supported. If |
2767 | defined to be \f(CW0\fR, then they are not. |
2981 | defined to be \f(CW0\fR, then they are not. |
2768 | .IP "\s-1EV_FORK_ENABLE\s0" 4 |
2982 | .IP "\s-1EV_FORK_ENABLE\s0" 4 |
2769 | .IX Item "EV_FORK_ENABLE" |
2983 | .IX Item "EV_FORK_ENABLE" |
2770 | If undefined or defined to be \f(CW1\fR, then fork watchers are supported. If |
2984 | If undefined or defined to be \f(CW1\fR, then fork watchers are supported. If |
|
|
2985 | defined to be \f(CW0\fR, then they are not. |
|
|
2986 | .IP "\s-1EV_ASYNC_ENABLE\s0" 4 |
|
|
2987 | .IX Item "EV_ASYNC_ENABLE" |
|
|
2988 | If undefined or defined to be \f(CW1\fR, then async watchers are supported. If |
2771 | defined to be \f(CW0\fR, then they are not. |
2989 | defined to be \f(CW0\fR, then they are not. |
2772 | .IP "\s-1EV_MINIMAL\s0" 4 |
2990 | .IP "\s-1EV_MINIMAL\s0" 4 |
2773 | .IX Item "EV_MINIMAL" |
2991 | .IX Item "EV_MINIMAL" |
2774 | If you need to shave off some kilobytes of code at the expense of some |
2992 | If you need to shave off some kilobytes of code at the expense of some |
2775 | speed, define this symbol to \f(CW1\fR. Currently only used for gcc to override |
2993 | speed, define this symbol to \f(CW1\fR. Currently only used for gcc to override |
… | |
… | |
2818 | .Sh "\s-1EXPORTED\s0 \s-1API\s0 \s-1SYMBOLS\s0" |
3036 | .Sh "\s-1EXPORTED\s0 \s-1API\s0 \s-1SYMBOLS\s0" |
2819 | .IX Subsection "EXPORTED API SYMBOLS" |
3037 | .IX Subsection "EXPORTED API SYMBOLS" |
2820 | If you need to re-export the \s-1API\s0 (e.g. via a dll) and you need a list of |
3038 | If you need to re-export the \s-1API\s0 (e.g. via a dll) and you need a list of |
2821 | exported symbols, you can use the provided \fISymbol.*\fR files which list |
3039 | exported symbols, you can use the provided \fISymbol.*\fR files which list |
2822 | all public symbols, one per line: |
3040 | all public symbols, one per line: |
2823 | .Sp |
3041 | .PP |
2824 | .Vb 2 |
3042 | .Vb 2 |
2825 | \& Symbols.ev for libev proper |
3043 | \& Symbols.ev for libev proper |
2826 | \& Symbols.event for the libevent emulation |
3044 | \& Symbols.event for the libevent emulation |
2827 | .Ve |
3045 | .Ve |
2828 | .Sp |
3046 | .PP |
2829 | This can also be used to rename all public symbols to avoid clashes with |
3047 | This can also be used to rename all public symbols to avoid clashes with |
2830 | multiple versions of libev linked together (which is obviously bad in |
3048 | multiple versions of libev linked together (which is obviously bad in |
2831 | itself, but sometimes it is inconvinient to avoid this). |
3049 | itself, but sometimes it is inconvinient to avoid this). |
2832 | .Sp |
3050 | .PP |
2833 | A sed command like this will create wrapper \f(CW\*(C`#define\*(C'\fR's that you need to |
3051 | A sed command like this will create wrapper \f(CW\*(C`#define\*(C'\fR's that you need to |
2834 | include before including \fIev.h\fR: |
3052 | include before including \fIev.h\fR: |
2835 | .Sp |
3053 | .PP |
2836 | .Vb 1 |
3054 | .Vb 1 |
2837 | \& <Symbols.ev sed -e "s/.*/#define & myprefix_&/" >wrap.h |
3055 | \& <Symbols.ev sed \-e "s/.*/#define & myprefix_&/" >wrap.h |
2838 | .Ve |
3056 | .Ve |
2839 | .Sp |
3057 | .PP |
2840 | This would create a file \fIwrap.h\fR which essentially looks like this: |
3058 | This would create a file \fIwrap.h\fR which essentially looks like this: |
2841 | .Sp |
3059 | .PP |
2842 | .Vb 4 |
3060 | .Vb 4 |
2843 | \& #define ev_backend myprefix_ev_backend |
3061 | \& #define ev_backend myprefix_ev_backend |
2844 | \& #define ev_check_start myprefix_ev_check_start |
3062 | \& #define ev_check_start myprefix_ev_check_start |
2845 | \& #define ev_check_stop myprefix_ev_check_stop |
3063 | \& #define ev_check_stop myprefix_ev_check_stop |
2846 | \& ... |
3064 | \& ... |
… | |
… | |
2852 | (<http://software.schmorp.de/pkg/EV.html>). It has the libev files in |
3070 | (<http://software.schmorp.de/pkg/EV.html>). It has the libev files in |
2853 | the \fIlibev/\fR subdirectory and includes them in the \fI\s-1EV/EVAPI\s0.h\fR (public |
3071 | the \fIlibev/\fR subdirectory and includes them in the \fI\s-1EV/EVAPI\s0.h\fR (public |
2854 | interface) and \fI\s-1EV\s0.xs\fR (implementation) files. Only the \fI\s-1EV\s0.xs\fR file |
3072 | interface) and \fI\s-1EV\s0.xs\fR (implementation) files. Only the \fI\s-1EV\s0.xs\fR file |
2855 | will be compiled. It is pretty complex because it provides its own header |
3073 | will be compiled. It is pretty complex because it provides its own header |
2856 | file. |
3074 | file. |
2857 | .Sp |
3075 | .PP |
2858 | The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file |
3076 | The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file |
2859 | that everybody includes and which overrides some configure choices: |
3077 | that everybody includes and which overrides some configure choices: |
2860 | .Sp |
3078 | .PP |
2861 | .Vb 9 |
3079 | .Vb 9 |
2862 | \& #define EV_MINIMAL 1 |
3080 | \& #define EV_MINIMAL 1 |
2863 | \& #define EV_USE_POLL 0 |
3081 | \& #define EV_USE_POLL 0 |
2864 | \& #define EV_MULTIPLICITY 0 |
3082 | \& #define EV_MULTIPLICITY 0 |
2865 | \& #define EV_PERIODIC_ENABLE 0 |
3083 | \& #define EV_PERIODIC_ENABLE 0 |
2866 | \& #define EV_STAT_ENABLE 0 |
3084 | \& #define EV_STAT_ENABLE 0 |
2867 | \& #define EV_FORK_ENABLE 0 |
3085 | \& #define EV_FORK_ENABLE 0 |
2868 | \& #define EV_CONFIG_H <config.h> |
3086 | \& #define EV_CONFIG_H <config.h> |
2869 | \& #define EV_MINPRI 0 |
3087 | \& #define EV_MINPRI 0 |
2870 | \& #define EV_MAXPRI 0 |
3088 | \& #define EV_MAXPRI 0 |
2871 | .Ve |
3089 | \& |
2872 | .Sp |
|
|
2873 | .Vb 1 |
|
|
2874 | \& #include "ev++.h" |
3090 | \& #include "ev++.h" |
2875 | .Ve |
3091 | .Ve |
2876 | .Sp |
3092 | .PP |
2877 | And a \fIev_cpp.C\fR implementation file that contains libev proper and is compiled: |
3093 | And a \fIev_cpp.C\fR implementation file that contains libev proper and is compiled: |
2878 | .Sp |
3094 | .PP |
2879 | .Vb 2 |
3095 | .Vb 2 |
2880 | \& #include "ev_cpp.h" |
3096 | \& #include "ev_cpp.h" |
2881 | \& #include "ev.c" |
3097 | \& #include "ev.c" |
2882 | .Ve |
3098 | .Ve |
2883 | .SH "COMPLEXITIES" |
3099 | .SH "COMPLEXITIES" |
2884 | .IX Header "COMPLEXITIES" |
3100 | .IX Header "COMPLEXITIES" |
2885 | In this section the complexities of (many of) the algorithms used inside |
3101 | In this section the complexities of (many of) the algorithms used inside |
2886 | libev will be explained. For complexity discussions about backends see the |
3102 | libev will be explained. For complexity discussions about backends see the |
2887 | documentation for \f(CW\*(C`ev_default_init\*(C'\fR. |
3103 | documentation for \f(CW\*(C`ev_default_init\*(C'\fR. |
2888 | .Sp |
3104 | .PP |
2889 | All of the following are about amortised time: If an array needs to be |
3105 | All of the following are about amortised time: If an array needs to be |
2890 | extended, libev needs to realloc and move the whole array, but this |
3106 | extended, libev needs to realloc and move the whole array, but this |
2891 | happens asymptotically never with higher number of elements, so O(1) might |
3107 | happens asymptotically never with higher number of elements, so O(1) might |
2892 | mean it might do a lengthy realloc operation in rare cases, but on average |
3108 | mean it might do a lengthy realloc operation in rare cases, but on average |
2893 | it is much faster and asymptotically approaches constant time. |
3109 | it is much faster and asymptotically approaches constant time. |
2894 | .RS 4 |
|
|
2895 | .IP "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" 4 |
3110 | .IP "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" 4 |
2896 | .IX Item "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" |
3111 | .IX Item "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" |
2897 | This means that, when you have a watcher that triggers in one hour and |
3112 | This means that, when you have a watcher that triggers in one hour and |
2898 | there are 100 watchers that would trigger before that then inserting will |
3113 | there are 100 watchers that would trigger before that then inserting will |
2899 | have to skip roughly seven (\f(CW\*(C`ld 100\*(C'\fR) of these watchers. |
3114 | have to skip roughly seven (\f(CW\*(C`ld 100\*(C'\fR) of these watchers. |
2900 | .IP "Changing timer/periodic watchers (by autorepeat or calling again): O(log skipped_other_timers)" 4 |
3115 | .IP "Changing timer/periodic watchers (by autorepeat or calling again): O(log skipped_other_timers)" 4 |
2901 | .IX Item "Changing timer/periodic watchers (by autorepeat or calling again): O(log skipped_other_timers)" |
3116 | .IX Item "Changing timer/periodic watchers (by autorepeat or calling again): O(log skipped_other_timers)" |
2902 | That means that changing a timer costs less than removing/adding them |
3117 | That means that changing a timer costs less than removing/adding them |
2903 | as only the relative motion in the event queue has to be paid for. |
3118 | as only the relative motion in the event queue has to be paid for. |
2904 | .IP "Starting io/check/prepare/idle/signal/child watchers: O(1)" 4 |
3119 | .IP "Starting io/check/prepare/idle/signal/child/fork/async watchers: O(1)" 4 |
2905 | .IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)" |
3120 | .IX Item "Starting io/check/prepare/idle/signal/child/fork/async watchers: O(1)" |
2906 | These just add the watcher into an array or at the head of a list. |
3121 | These just add the watcher into an array or at the head of a list. |
2907 | .IP "Stopping check/prepare/idle watchers: O(1)" 4 |
3122 | .IP "Stopping check/prepare/idle/fork/async watchers: O(1)" 4 |
2908 | .IX Item "Stopping check/prepare/idle watchers: O(1)" |
3123 | .IX Item "Stopping check/prepare/idle/fork/async watchers: O(1)" |
2909 | .PD 0 |
3124 | .PD 0 |
2910 | .IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % \s-1EV_PID_HASHSIZE\s0))" 4 |
3125 | .IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % \s-1EV_PID_HASHSIZE\s0))" 4 |
2911 | .IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))" |
3126 | .IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))" |
2912 | .PD |
3127 | .PD |
2913 | These watchers are stored in lists then need to be walked to find the |
3128 | These watchers are stored in lists then need to be walked to find the |
… | |
… | |
2929 | .IX Item "Priority handling: O(number_of_priorities)" |
3144 | .IX Item "Priority handling: O(number_of_priorities)" |
2930 | .PD |
3145 | .PD |
2931 | Priorities are implemented by allocating some space for each |
3146 | Priorities are implemented by allocating some space for each |
2932 | priority. When doing priority-based operations, libev usually has to |
3147 | priority. When doing priority-based operations, libev usually has to |
2933 | linearly search all the priorities, but starting/stopping and activating |
3148 | linearly search all the priorities, but starting/stopping and activating |
2934 | watchers becomes O(1) w.r.t. prioritiy handling. |
3149 | watchers becomes O(1) w.r.t. priority handling. |
2935 | .RE |
3150 | .IP "Sending an ev_async: O(1)" 4 |
2936 | .RS 4 |
3151 | .IX Item "Sending an ev_async: O(1)" |
|
|
3152 | .PD 0 |
|
|
3153 | .IP "Processing ev_async_send: O(number_of_async_watchers)" 4 |
|
|
3154 | .IX Item "Processing ev_async_send: O(number_of_async_watchers)" |
|
|
3155 | .IP "Processing signals: O(max_signal_number)" 4 |
|
|
3156 | .IX Item "Processing signals: O(max_signal_number)" |
|
|
3157 | .PD |
|
|
3158 | Sending involves a syscall \fIiff\fR there were no other \f(CW\*(C`ev_async_send\*(C'\fR |
|
|
3159 | calls in the current loop iteration. Checking for async and signal events |
|
|
3160 | involves iterating over all running async watchers or all signal numbers. |
|
|
3161 | .SH "Win32 platform limitations and workarounds" |
|
|
3162 | .IX Header "Win32 platform limitations and workarounds" |
|
|
3163 | Win32 doesn't support any of the standards (e.g. \s-1POSIX\s0) that libev |
|
|
3164 | requires, and its I/O model is fundamentally incompatible with the \s-1POSIX\s0 |
|
|
3165 | model. Libev still offers limited functionality on this platform in |
|
|
3166 | the form of the \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR backend, and only supports socket |
|
|
3167 | descriptors. This only applies when using Win32 natively, not when using |
|
|
3168 | e.g. cygwin. |
|
|
3169 | .PP |
|
|
3170 | There is no supported compilation method available on windows except |
|
|
3171 | embedding it into other applications. |
|
|
3172 | .PP |
|
|
3173 | Due to the many, low, and arbitrary limits on the win32 platform and the |
|
|
3174 | abysmal performance of winsockets, using a large number of sockets is not |
|
|
3175 | recommended (and not reasonable). If your program needs to use more than |
|
|
3176 | a hundred or so sockets, then likely it needs to use a totally different |
|
|
3177 | implementation for windows, as libev offers the \s-1POSIX\s0 model, which cannot |
|
|
3178 | be implemented efficiently on windows (microsoft monopoly games). |
|
|
3179 | .IP "The winsocket select function" 4 |
|
|
3180 | .IX Item "The winsocket select function" |
|
|
3181 | The winsocket \f(CW\*(C`select\*(C'\fR function doesn't follow \s-1POSIX\s0 in that it requires |
|
|
3182 | socket \fIhandles\fR and not socket \fIfile descriptors\fR. This makes select |
|
|
3183 | very inefficient, and also requires a mapping from file descriptors |
|
|
3184 | to socket handles. See the discussion of the \f(CW\*(C`EV_SELECT_USE_FD_SET\*(C'\fR, |
|
|
3185 | \&\f(CW\*(C`EV_SELECT_IS_WINSOCKET\*(C'\fR and \f(CW\*(C`EV_FD_TO_WIN32_HANDLE\*(C'\fR preprocessor |
|
|
3186 | symbols for more info. |
|
|
3187 | .Sp |
|
|
3188 | The configuration for a \*(L"naked\*(R" win32 using the microsoft runtime |
|
|
3189 | libraries and raw winsocket select is: |
|
|
3190 | .Sp |
|
|
3191 | .Vb 2 |
|
|
3192 | \& #define EV_USE_SELECT 1 |
|
|
3193 | \& #define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */ |
|
|
3194 | .Ve |
|
|
3195 | .Sp |
|
|
3196 | Note that winsockets handling of fd sets is O(n), so you can easily get a |
|
|
3197 | complexity in the O(nA\*^X) range when using win32. |
|
|
3198 | .IP "Limited number of file descriptors" 4 |
|
|
3199 | .IX Item "Limited number of file descriptors" |
|
|
3200 | Windows has numerous arbitrary (and low) limits on things. Early versions |
|
|
3201 | of winsocket's select only supported waiting for a max. of \f(CW64\fR handles |
|
|
3202 | (probably owning to the fact that all windows kernels can only wait for |
|
|
3203 | \&\f(CW64\fR things at the same time internally; microsoft recommends spawning a |
|
|
3204 | chain of threads and wait for 63 handles and the previous thread in each). |
|
|
3205 | .Sp |
|
|
3206 | Newer versions support more handles, but you need to define \f(CW\*(C`FD_SETSIZE\*(C'\fR |
|
|
3207 | to some high number (e.g. \f(CW2048\fR) before compiling the winsocket select |
|
|
3208 | call (which might be in libev or elsewhere, for example, perl does its own |
|
|
3209 | select emulation on windows). |
|
|
3210 | .Sp |
|
|
3211 | Another limit is the number of file descriptors in the microsoft runtime |
|
|
3212 | libraries, which by default is \f(CW64\fR (there must be a hidden \fI64\fR fetish |
|
|
3213 | or something like this inside microsoft). You can increase this by calling |
|
|
3214 | \&\f(CW\*(C`_setmaxstdio\*(C'\fR, which can increase this limit to \f(CW2048\fR (another |
|
|
3215 | arbitrary limit), but is broken in many versions of the microsoft runtime |
|
|
3216 | libraries. |
|
|
3217 | .Sp |
|
|
3218 | This might get you to about \f(CW512\fR or \f(CW2048\fR sockets (depending on |
|
|
3219 | windows version and/or the phase of the moon). To get more, you need to |
|
|
3220 | wrap all I/O functions and provide your own fd management, but the cost of |
|
|
3221 | calling select (O(nA\*^X)) will likely make this unworkable. |
2937 | .SH "AUTHOR" |
3222 | .SH "AUTHOR" |
2938 | .IX Header "AUTHOR" |
3223 | .IX Header "AUTHOR" |
2939 | Marc Lehmann <libev@schmorp.de>. |
3224 | Marc Lehmann <libev@schmorp.de>. |
|
|
3225 | .SH "POD ERRORS" |
|
|
3226 | .IX Header "POD ERRORS" |
|
|
3227 | Hey! \fBThe above document had some coding errors, which are explained below:\fR |
|
|
3228 | .IP "Around line 2951:" 4 |
|
|
3229 | .IX Item "Around line 2951:" |
|
|
3230 | You forgot a '=back' before '=head2' |