… | |
… | |
126 | . ds Ae AE |
126 | . ds Ae AE |
127 | .\} |
127 | .\} |
128 | .rm #[ #] #H #V #F C |
128 | .rm #[ #] #H #V #F C |
129 | .\" ======================================================================== |
129 | .\" ======================================================================== |
130 | .\" |
130 | .\" |
131 | .IX Title ""<STANDARD INPUT>" 1" |
131 | .IX Title "EV 1" |
132 | .TH "<STANDARD INPUT>" 1 "2007-11-28" "perl v5.8.8" "User Contributed Perl Documentation" |
132 | .TH EV 1 "2007-12-25" "perl v5.8.8" "User Contributed Perl Documentation" |
133 | .SH "NAME" |
133 | .SH "NAME" |
134 | libev \- a high performance full\-featured event loop written in C |
134 | libev \- a high performance full\-featured event loop written in C |
135 | .SH "SYNOPSIS" |
135 | .SH "SYNOPSIS" |
136 | .IX Header "SYNOPSIS" |
136 | .IX Header "SYNOPSIS" |
137 | .Vb 1 |
137 | .Vb 1 |
138 | \& #include <ev.h> |
138 | \& #include <ev.h> |
139 | .Ve |
139 | .Ve |
140 | .SH "EXAMPLE PROGRAM" |
140 | .Sh "\s-1EXAMPLE\s0 \s-1PROGRAM\s0" |
141 | .IX Header "EXAMPLE PROGRAM" |
141 | .IX Subsection "EXAMPLE PROGRAM" |
142 | .Vb 1 |
142 | .Vb 1 |
143 | \& #include <ev.h> |
143 | \& #include <ev.h> |
144 | .Ve |
144 | .Ve |
145 | .PP |
145 | .PP |
146 | .Vb 2 |
146 | .Vb 2 |
… | |
… | |
196 | \& return 0; |
196 | \& return 0; |
197 | \& } |
197 | \& } |
198 | .Ve |
198 | .Ve |
199 | .SH "DESCRIPTION" |
199 | .SH "DESCRIPTION" |
200 | .IX Header "DESCRIPTION" |
200 | .IX Header "DESCRIPTION" |
|
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201 | The newest version of this document is also available as a html-formatted |
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202 | web page you might find easier to navigate when reading it for the first |
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203 | time: <http://cvs.schmorp.de/libev/ev.html>. |
|
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204 | .PP |
201 | Libev is an event loop: you register interest in certain events (such as a |
205 | Libev is an event loop: you register interest in certain events (such as a |
202 | file descriptor being readable or a timeout occuring), and it will manage |
206 | file descriptor being readable or a timeout occurring), and it will manage |
203 | these event sources and provide your program with events. |
207 | these event sources and provide your program with events. |
204 | .PP |
208 | .PP |
205 | To do this, it must take more or less complete control over your process |
209 | To do this, it must take more or less complete control over your process |
206 | (or thread) by executing the \fIevent loop\fR handler, and will then |
210 | (or thread) by executing the \fIevent loop\fR handler, and will then |
207 | communicate events via a callback mechanism. |
211 | communicate events via a callback mechanism. |
208 | .PP |
212 | .PP |
209 | You register interest in certain events by registering so-called \fIevent |
213 | You register interest in certain events by registering so-called \fIevent |
210 | watchers\fR, which are relatively small C structures you initialise with the |
214 | watchers\fR, which are relatively small C structures you initialise with the |
211 | details of the event, and then hand it over to libev by \fIstarting\fR the |
215 | details of the event, and then hand it over to libev by \fIstarting\fR the |
212 | watcher. |
216 | watcher. |
213 | .SH "FEATURES" |
217 | .Sh "\s-1FEATURES\s0" |
214 | .IX Header "FEATURES" |
218 | .IX Subsection "FEATURES" |
215 | Libev supports \f(CW\*(C`select\*(C'\fR, \f(CW\*(C`poll\*(C'\fR, the Linux-specific \f(CW\*(C`epoll\*(C'\fR, the |
219 | Libev supports \f(CW\*(C`select\*(C'\fR, \f(CW\*(C`poll\*(C'\fR, the Linux-specific \f(CW\*(C`epoll\*(C'\fR, the |
216 | BSD-specific \f(CW\*(C`kqueue\*(C'\fR and the Solaris-specific event port mechanisms |
220 | BSD-specific \f(CW\*(C`kqueue\*(C'\fR and the Solaris-specific event port mechanisms |
217 | for file descriptor events (\f(CW\*(C`ev_io\*(C'\fR), the Linux \f(CW\*(C`inotify\*(C'\fR interface |
221 | for file descriptor events (\f(CW\*(C`ev_io\*(C'\fR), the Linux \f(CW\*(C`inotify\*(C'\fR interface |
218 | (for \f(CW\*(C`ev_stat\*(C'\fR), relative timers (\f(CW\*(C`ev_timer\*(C'\fR), absolute timers |
222 | (for \f(CW\*(C`ev_stat\*(C'\fR), relative timers (\f(CW\*(C`ev_timer\*(C'\fR), absolute timers |
219 | with customised rescheduling (\f(CW\*(C`ev_periodic\*(C'\fR), synchronous signals |
223 | with customised rescheduling (\f(CW\*(C`ev_periodic\*(C'\fR), synchronous signals |
… | |
… | |
224 | (\f(CW\*(C`ev_fork\*(C'\fR). |
228 | (\f(CW\*(C`ev_fork\*(C'\fR). |
225 | .PP |
229 | .PP |
226 | It also is quite fast (see this |
230 | It also is quite fast (see this |
227 | benchmark comparing it to libevent |
231 | benchmark comparing it to libevent |
228 | for example). |
232 | for example). |
229 | .SH "CONVENTIONS" |
233 | .Sh "\s-1CONVENTIONS\s0" |
230 | .IX Header "CONVENTIONS" |
234 | .IX Subsection "CONVENTIONS" |
231 | Libev is very configurable. In this manual the default configuration will |
235 | Libev is very configurable. In this manual the default configuration will |
232 | be described, which supports multiple event loops. For more info about |
236 | be described, which supports multiple event loops. For more info about |
233 | various configuration options please have a look at \fB\s-1EMBED\s0\fR section in |
237 | various configuration options please have a look at \fB\s-1EMBED\s0\fR section in |
234 | this manual. If libev was configured without support for multiple event |
238 | this manual. If libev was configured without support for multiple event |
235 | loops, then all functions taking an initial argument of name \f(CW\*(C`loop\*(C'\fR |
239 | loops, then all functions taking an initial argument of name \f(CW\*(C`loop\*(C'\fR |
236 | (which is always of type \f(CW\*(C`struct ev_loop *\*(C'\fR) will not have this argument. |
240 | (which is always of type \f(CW\*(C`struct ev_loop *\*(C'\fR) will not have this argument. |
237 | .SH "TIME REPRESENTATION" |
241 | .Sh "\s-1TIME\s0 \s-1REPRESENTATION\s0" |
238 | .IX Header "TIME REPRESENTATION" |
242 | .IX Subsection "TIME REPRESENTATION" |
239 | Libev represents time as a single floating point number, representing the |
243 | Libev represents time as a single floating point number, representing the |
240 | (fractional) number of seconds since the (\s-1POSIX\s0) epoch (somewhere near |
244 | (fractional) number of seconds since the (\s-1POSIX\s0) epoch (somewhere near |
241 | the beginning of 1970, details are complicated, don't ask). This type is |
245 | the beginning of 1970, details are complicated, don't ask). This type is |
242 | called \f(CW\*(C`ev_tstamp\*(C'\fR, which is what you should use too. It usually aliases |
246 | called \f(CW\*(C`ev_tstamp\*(C'\fR, which is what you should use too. It usually aliases |
243 | to the \f(CW\*(C`double\*(C'\fR type in C, and when you need to do any calculations on |
247 | to the \f(CW\*(C`double\*(C'\fR type in C, and when you need to do any calculations on |
244 | it, you should treat it as such. |
248 | it, you should treat it as some floatingpoint value. Unlike the name |
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249 | component \f(CW\*(C`stamp\*(C'\fR might indicate, it is also used for time differences |
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250 | throughout libev. |
245 | .SH "GLOBAL FUNCTIONS" |
251 | .SH "GLOBAL FUNCTIONS" |
246 | .IX Header "GLOBAL FUNCTIONS" |
252 | .IX Header "GLOBAL FUNCTIONS" |
247 | These functions can be called anytime, even before initialising the |
253 | These functions can be called anytime, even before initialising the |
248 | library in any way. |
254 | library in any way. |
249 | .IP "ev_tstamp ev_time ()" 4 |
255 | .IP "ev_tstamp ev_time ()" 4 |
250 | .IX Item "ev_tstamp ev_time ()" |
256 | .IX Item "ev_tstamp ev_time ()" |
251 | Returns the current time as libev would use it. Please note that the |
257 | Returns the current time as libev would use it. Please note that the |
252 | \&\f(CW\*(C`ev_now\*(C'\fR function is usually faster and also often returns the timestamp |
258 | \&\f(CW\*(C`ev_now\*(C'\fR function is usually faster and also often returns the timestamp |
253 | you actually want to know. |
259 | you actually want to know. |
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260 | .IP "ev_sleep (ev_tstamp interval)" 4 |
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261 | .IX Item "ev_sleep (ev_tstamp interval)" |
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262 | Sleep for the given interval: The current thread will be blocked until |
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263 | either it is interrupted or the given time interval has passed. Basically |
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264 | this is a subsecond-resolution \f(CW\*(C`sleep ()\*(C'\fR. |
254 | .IP "int ev_version_major ()" 4 |
265 | .IP "int ev_version_major ()" 4 |
255 | .IX Item "int ev_version_major ()" |
266 | .IX Item "int ev_version_major ()" |
256 | .PD 0 |
267 | .PD 0 |
257 | .IP "int ev_version_minor ()" 4 |
268 | .IP "int ev_version_minor ()" 4 |
258 | .IX Item "int ev_version_minor ()" |
269 | .IX Item "int ev_version_minor ()" |
259 | .PD |
270 | .PD |
260 | You can find out the major and minor version numbers of the library |
271 | You can find out the major and minor \s-1ABI\s0 version numbers of the library |
261 | you linked against by calling the functions \f(CW\*(C`ev_version_major\*(C'\fR and |
272 | you linked against by calling the functions \f(CW\*(C`ev_version_major\*(C'\fR and |
262 | \&\f(CW\*(C`ev_version_minor\*(C'\fR. If you want, you can compare against the global |
273 | \&\f(CW\*(C`ev_version_minor\*(C'\fR. If you want, you can compare against the global |
263 | symbols \f(CW\*(C`EV_VERSION_MAJOR\*(C'\fR and \f(CW\*(C`EV_VERSION_MINOR\*(C'\fR, which specify the |
274 | symbols \f(CW\*(C`EV_VERSION_MAJOR\*(C'\fR and \f(CW\*(C`EV_VERSION_MINOR\*(C'\fR, which specify the |
264 | version of the library your program was compiled against. |
275 | version of the library your program was compiled against. |
265 | .Sp |
276 | .Sp |
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277 | These version numbers refer to the \s-1ABI\s0 version of the library, not the |
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278 | release version. |
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279 | .Sp |
266 | Usually, it's a good idea to terminate if the major versions mismatch, |
280 | Usually, it's a good idea to terminate if the major versions mismatch, |
267 | as this indicates an incompatible change. Minor versions are usually |
281 | as this indicates an incompatible change. Minor versions are usually |
268 | compatible to older versions, so a larger minor version alone is usually |
282 | compatible to older versions, so a larger minor version alone is usually |
269 | not a problem. |
283 | not a problem. |
270 | .Sp |
284 | .Sp |
271 | Example: Make sure we haven't accidentally been linked against the wrong |
285 | Example: Make sure we haven't accidentally been linked against the wrong |
272 | version. |
286 | version. |
… | |
… | |
411 | or setgid) then libev will \fInot\fR look at the environment variable |
425 | or setgid) then libev will \fInot\fR look at the environment variable |
412 | \&\f(CW\*(C`LIBEV_FLAGS\*(C'\fR. Otherwise (the default), this environment variable will |
426 | \&\f(CW\*(C`LIBEV_FLAGS\*(C'\fR. Otherwise (the default), this environment variable will |
413 | override the flags completely if it is found in the environment. This is |
427 | override the flags completely if it is found in the environment. This is |
414 | useful to try out specific backends to test their performance, or to work |
428 | useful to try out specific backends to test their performance, or to work |
415 | around bugs. |
429 | around bugs. |
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430 | .ie n .IP """EVFLAG_FORKCHECK""" 4 |
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431 | .el .IP "\f(CWEVFLAG_FORKCHECK\fR" 4 |
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432 | .IX Item "EVFLAG_FORKCHECK" |
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433 | Instead of calling \f(CW\*(C`ev_default_fork\*(C'\fR or \f(CW\*(C`ev_loop_fork\*(C'\fR manually after |
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434 | a fork, you can also make libev check for a fork in each iteration by |
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435 | enabling this flag. |
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436 | .Sp |
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437 | This works by calling \f(CW\*(C`getpid ()\*(C'\fR on every iteration of the loop, |
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438 | and thus this might slow down your event loop if you do a lot of loop |
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439 | iterations and little real work, but is usually not noticeable (on my |
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440 | Linux system for example, \f(CW\*(C`getpid\*(C'\fR is actually a simple 5\-insn sequence |
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441 | without a syscall and thus \fIvery\fR fast, but my Linux system also has |
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442 | \&\f(CW\*(C`pthread_atfork\*(C'\fR which is even faster). |
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443 | .Sp |
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444 | The big advantage of this flag is that you can forget about fork (and |
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445 | forget about forgetting to tell libev about forking) when you use this |
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446 | flag. |
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447 | .Sp |
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448 | This flag setting cannot be overriden or specified in the \f(CW\*(C`LIBEV_FLAGS\*(C'\fR |
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449 | environment variable. |
416 | .ie n .IP """EVBACKEND_SELECT"" (value 1, portable select backend)" 4 |
450 | .ie n .IP """EVBACKEND_SELECT"" (value 1, portable select backend)" 4 |
417 | .el .IP "\f(CWEVBACKEND_SELECT\fR (value 1, portable select backend)" 4 |
451 | .el .IP "\f(CWEVBACKEND_SELECT\fR (value 1, portable select backend)" 4 |
418 | .IX Item "EVBACKEND_SELECT (value 1, portable select backend)" |
452 | .IX Item "EVBACKEND_SELECT (value 1, portable select backend)" |
419 | This is your standard \fIselect\fR\|(2) backend. Not \fIcompletely\fR standard, as |
453 | This is your standard \fIselect\fR\|(2) backend. Not \fIcompletely\fR standard, as |
420 | libev tries to roll its own fd_set with no limits on the number of fds, |
454 | libev tries to roll its own fd_set with no limits on the number of fds, |
421 | but if that fails, expect a fairly low limit on the number of fds when |
455 | but if that fails, expect a fairly low limit on the number of fds when |
422 | using this backend. It doesn't scale too well (O(highest_fd)), but its usually |
456 | using this backend. It doesn't scale too well (O(highest_fd)), but its |
423 | the fastest backend for a low number of fds. |
457 | usually the fastest backend for a low number of (low\-numbered :) fds. |
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458 | .Sp |
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459 | To get good performance out of this backend you need a high amount of |
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460 | parallelity (most of the file descriptors should be busy). If you are |
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461 | writing a server, you should \f(CW\*(C`accept ()\*(C'\fR in a loop to accept as many |
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462 | connections as possible during one iteration. You might also want to have |
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463 | a look at \f(CW\*(C`ev_set_io_collect_interval ()\*(C'\fR to increase the amount of |
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464 | readyness notifications you get per iteration. |
424 | .ie n .IP """EVBACKEND_POLL"" (value 2, poll backend, available everywhere except on windows)" 4 |
465 | .ie n .IP """EVBACKEND_POLL"" (value 2, poll backend, available everywhere except on windows)" 4 |
425 | .el .IP "\f(CWEVBACKEND_POLL\fR (value 2, poll backend, available everywhere except on windows)" 4 |
466 | .el .IP "\f(CWEVBACKEND_POLL\fR (value 2, poll backend, available everywhere except on windows)" 4 |
426 | .IX Item "EVBACKEND_POLL (value 2, poll backend, available everywhere except on windows)" |
467 | .IX Item "EVBACKEND_POLL (value 2, poll backend, available everywhere except on windows)" |
427 | And this is your standard \fIpoll\fR\|(2) backend. It's more complicated than |
468 | And this is your standard \fIpoll\fR\|(2) backend. It's more complicated |
428 | select, but handles sparse fds better and has no artificial limit on the |
469 | than select, but handles sparse fds better and has no artificial |
429 | number of fds you can use (except it will slow down considerably with a |
470 | limit on the number of fds you can use (except it will slow down |
430 | lot of inactive fds). It scales similarly to select, i.e. O(total_fds). |
471 | considerably with a lot of inactive fds). It scales similarly to select, |
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472 | i.e. O(total_fds). See the entry for \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR, above, for |
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473 | performance tips. |
431 | .ie n .IP """EVBACKEND_EPOLL"" (value 4, Linux)" 4 |
474 | .ie n .IP """EVBACKEND_EPOLL"" (value 4, Linux)" 4 |
432 | .el .IP "\f(CWEVBACKEND_EPOLL\fR (value 4, Linux)" 4 |
475 | .el .IP "\f(CWEVBACKEND_EPOLL\fR (value 4, Linux)" 4 |
433 | .IX Item "EVBACKEND_EPOLL (value 4, Linux)" |
476 | .IX Item "EVBACKEND_EPOLL (value 4, Linux)" |
434 | For few fds, this backend is a bit little slower than poll and select, |
477 | For few fds, this backend is a bit little slower than poll and select, |
435 | but it scales phenomenally better. While poll and select usually scale like |
478 | but it scales phenomenally better. While poll and select usually scale |
436 | O(total_fds) where n is the total number of fds (or the highest fd), epoll scales |
479 | like O(total_fds) where n is the total number of fds (or the highest fd), |
437 | either O(1) or O(active_fds). |
480 | epoll scales either O(1) or O(active_fds). The epoll design has a number |
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481 | of shortcomings, such as silently dropping events in some hard-to-detect |
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482 | cases and rewiring a syscall per fd change, no fork support and bad |
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483 | support for dup. |
438 | .Sp |
484 | .Sp |
439 | While stopping and starting an I/O watcher in the same iteration will |
485 | While stopping, setting and starting an I/O watcher in the same iteration |
440 | result in some caching, there is still a syscall per such incident |
486 | will result in some caching, there is still a syscall per such incident |
441 | (because the fd could point to a different file description now), so its |
487 | (because the fd could point to a different file description now), so its |
442 | best to avoid that. Also, \fIdup()\fRed file descriptors might not work very |
488 | best to avoid that. Also, \f(CW\*(C`dup ()\*(C'\fR'ed file descriptors might not work |
443 | well if you register events for both fds. |
489 | very well if you register events for both fds. |
444 | .Sp |
490 | .Sp |
445 | Please note that epoll sometimes generates spurious notifications, so you |
491 | Please note that epoll sometimes generates spurious notifications, so you |
446 | need to use non-blocking I/O or other means to avoid blocking when no data |
492 | need to use non-blocking I/O or other means to avoid blocking when no data |
447 | (or space) is available. |
493 | (or space) is available. |
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494 | .Sp |
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495 | Best performance from this backend is achieved by not unregistering all |
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496 | watchers for a file descriptor until it has been closed, if possible, i.e. |
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497 | keep at least one watcher active per fd at all times. |
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498 | .Sp |
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499 | While nominally embeddeble in other event loops, this feature is broken in |
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500 | all kernel versions tested so far. |
448 | .ie n .IP """EVBACKEND_KQUEUE"" (value 8, most \s-1BSD\s0 clones)" 4 |
501 | .ie n .IP """EVBACKEND_KQUEUE"" (value 8, most \s-1BSD\s0 clones)" 4 |
449 | .el .IP "\f(CWEVBACKEND_KQUEUE\fR (value 8, most \s-1BSD\s0 clones)" 4 |
502 | .el .IP "\f(CWEVBACKEND_KQUEUE\fR (value 8, most \s-1BSD\s0 clones)" 4 |
450 | .IX Item "EVBACKEND_KQUEUE (value 8, most BSD clones)" |
503 | .IX Item "EVBACKEND_KQUEUE (value 8, most BSD clones)" |
451 | Kqueue deserves special mention, as at the time of this writing, it |
504 | Kqueue deserves special mention, as at the time of this writing, it |
452 | was broken on all BSDs except NetBSD (usually it doesn't work with |
505 | was broken on all BSDs except NetBSD (usually it doesn't work reliably |
453 | anything but sockets and pipes, except on Darwin, where of course its |
506 | with anything but sockets and pipes, except on Darwin, where of course |
454 | completely useless). For this reason its not being \*(L"autodetected\*(R" |
507 | it's completely useless). For this reason it's not being \*(L"autodetected\*(R" |
455 | unless you explicitly specify it explicitly in the flags (i.e. using |
508 | unless you explicitly specify it explicitly in the flags (i.e. using |
456 | \&\f(CW\*(C`EVBACKEND_KQUEUE\*(C'\fR). |
509 | \&\f(CW\*(C`EVBACKEND_KQUEUE\*(C'\fR) or libev was compiled on a known-to-be-good (\-enough) |
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510 | system like NetBSD. |
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511 | .Sp |
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512 | You still can embed kqueue into a normal poll or select backend and use it |
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513 | only for sockets (after having made sure that sockets work with kqueue on |
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514 | the target platform). See \f(CW\*(C`ev_embed\*(C'\fR watchers for more info. |
457 | .Sp |
515 | .Sp |
458 | It scales in the same way as the epoll backend, but the interface to the |
516 | It scales in the same way as the epoll backend, but the interface to the |
459 | kernel is more efficient (which says nothing about its actual speed, of |
517 | kernel is more efficient (which says nothing about its actual speed, of |
460 | course). While starting and stopping an I/O watcher does not cause an |
518 | course). While stopping, setting and starting an I/O watcher does never |
461 | extra syscall as with epoll, it still adds up to four event changes per |
519 | cause an extra syscall as with \f(CW\*(C`EVBACKEND_EPOLL\*(C'\fR, it still adds up to |
462 | incident, so its best to avoid that. |
520 | two event changes per incident, support for \f(CW\*(C`fork ()\*(C'\fR is very bad and it |
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521 | drops fds silently in similarly hard-to-detect cases. |
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522 | .Sp |
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523 | This backend usually performs well under most conditions. |
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524 | .Sp |
|
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525 | While nominally embeddable in other event loops, this doesn't work |
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526 | everywhere, so you might need to test for this. And since it is broken |
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527 | almost everywhere, you should only use it when you have a lot of sockets |
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528 | (for which it usually works), by embedding it into another event loop |
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529 | (e.g. \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR or \f(CW\*(C`EVBACKEND_POLL\*(C'\fR) and using it only for |
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530 | sockets. |
463 | .ie n .IP """EVBACKEND_DEVPOLL"" (value 16, Solaris 8)" 4 |
531 | .ie n .IP """EVBACKEND_DEVPOLL"" (value 16, Solaris 8)" 4 |
464 | .el .IP "\f(CWEVBACKEND_DEVPOLL\fR (value 16, Solaris 8)" 4 |
532 | .el .IP "\f(CWEVBACKEND_DEVPOLL\fR (value 16, Solaris 8)" 4 |
465 | .IX Item "EVBACKEND_DEVPOLL (value 16, Solaris 8)" |
533 | .IX Item "EVBACKEND_DEVPOLL (value 16, Solaris 8)" |
466 | This is not implemented yet (and might never be). |
534 | This is not implemented yet (and might never be, unless you send me an |
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535 | implementation). According to reports, \f(CW\*(C`/dev/poll\*(C'\fR only supports sockets |
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536 | and is not embeddable, which would limit the usefulness of this backend |
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537 | immensely. |
467 | .ie n .IP """EVBACKEND_PORT"" (value 32, Solaris 10)" 4 |
538 | .ie n .IP """EVBACKEND_PORT"" (value 32, Solaris 10)" 4 |
468 | .el .IP "\f(CWEVBACKEND_PORT\fR (value 32, Solaris 10)" 4 |
539 | .el .IP "\f(CWEVBACKEND_PORT\fR (value 32, Solaris 10)" 4 |
469 | .IX Item "EVBACKEND_PORT (value 32, Solaris 10)" |
540 | .IX Item "EVBACKEND_PORT (value 32, Solaris 10)" |
470 | This uses the Solaris 10 port mechanism. As with everything on Solaris, |
541 | This uses the Solaris 10 event port mechanism. As with everything on Solaris, |
471 | it's really slow, but it still scales very well (O(active_fds)). |
542 | it's really slow, but it still scales very well (O(active_fds)). |
472 | .Sp |
543 | .Sp |
473 | Please note that solaris ports can result in a lot of spurious |
544 | Please note that solaris event ports can deliver a lot of spurious |
474 | notifications, so you need to use non-blocking I/O or other means to avoid |
545 | notifications, so you need to use non-blocking I/O or other means to avoid |
475 | blocking when no data (or space) is available. |
546 | blocking when no data (or space) is available. |
|
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547 | .Sp |
|
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548 | 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 |
|
|
550 | descriptors a \*(L"slow\*(R" \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR or \f(CW\*(C`EVBACKEND_POLL\*(C'\fR backend |
|
|
551 | might perform better. |
476 | .ie n .IP """EVBACKEND_ALL""" 4 |
552 | .ie n .IP """EVBACKEND_ALL""" 4 |
477 | .el .IP "\f(CWEVBACKEND_ALL\fR" 4 |
553 | .el .IP "\f(CWEVBACKEND_ALL\fR" 4 |
478 | .IX Item "EVBACKEND_ALL" |
554 | .IX Item "EVBACKEND_ALL" |
479 | Try all backends (even potentially broken ones that wouldn't be tried |
555 | Try all backends (even potentially broken ones that wouldn't be tried |
480 | with \f(CW\*(C`EVFLAG_AUTO\*(C'\fR). Since this is a mask, you can do stuff such as |
556 | with \f(CW\*(C`EVFLAG_AUTO\*(C'\fR). Since this is a mask, you can do stuff such as |
481 | \&\f(CW\*(C`EVBACKEND_ALL & ~EVBACKEND_KQUEUE\*(C'\fR. |
557 | \&\f(CW\*(C`EVBACKEND_ALL & ~EVBACKEND_KQUEUE\*(C'\fR. |
|
|
558 | .Sp |
|
|
559 | It is definitely not recommended to use this flag. |
482 | .RE |
560 | .RE |
483 | .RS 4 |
561 | .RS 4 |
484 | .Sp |
562 | .Sp |
485 | If one or more of these are ored into the flags value, then only these |
563 | If one or more of these are ored into the flags value, then only these |
486 | backends will be tried (in the reverse order as given here). If none are |
564 | backends will be tried (in the reverse order as given here). If none are |
… | |
… | |
528 | Destroys the default loop again (frees all memory and kernel state |
606 | Destroys the default loop again (frees all memory and kernel state |
529 | etc.). None of the active event watchers will be stopped in the normal |
607 | etc.). None of the active event watchers will be stopped in the normal |
530 | sense, so e.g. \f(CW\*(C`ev_is_active\*(C'\fR might still return true. It is your |
608 | sense, so e.g. \f(CW\*(C`ev_is_active\*(C'\fR might still return true. It is your |
531 | responsibility to either stop all watchers cleanly yoursef \fIbefore\fR |
609 | responsibility to either stop all watchers cleanly yoursef \fIbefore\fR |
532 | calling this function, or cope with the fact afterwards (which is usually |
610 | calling this function, or cope with the fact afterwards (which is usually |
533 | the easiest thing, youc na just ignore the watchers and/or \f(CW\*(C`free ()\*(C'\fR them |
611 | the easiest thing, you can just ignore the watchers and/or \f(CW\*(C`free ()\*(C'\fR them |
534 | for example). |
612 | for example). |
|
|
613 | .Sp |
|
|
614 | Note that certain global state, such as signal state, will not be freed by |
|
|
615 | this function, and related watchers (such as signal and child watchers) |
|
|
616 | would need to be stopped manually. |
|
|
617 | .Sp |
|
|
618 | In general it is not advisable to call this function except in the |
|
|
619 | rare occasion where you really need to free e.g. the signal handling |
|
|
620 | pipe fds. If you need dynamically allocated loops it is better to use |
|
|
621 | \&\f(CW\*(C`ev_loop_new\*(C'\fR and \f(CW\*(C`ev_loop_destroy\*(C'\fR). |
535 | .IP "ev_loop_destroy (loop)" 4 |
622 | .IP "ev_loop_destroy (loop)" 4 |
536 | .IX Item "ev_loop_destroy (loop)" |
623 | .IX Item "ev_loop_destroy (loop)" |
537 | Like \f(CW\*(C`ev_default_destroy\*(C'\fR, but destroys an event loop created by an |
624 | Like \f(CW\*(C`ev_default_destroy\*(C'\fR, but destroys an event loop created by an |
538 | earlier call to \f(CW\*(C`ev_loop_new\*(C'\fR. |
625 | earlier call to \f(CW\*(C`ev_loop_new\*(C'\fR. |
539 | .IP "ev_default_fork ()" 4 |
626 | .IP "ev_default_fork ()" 4 |
… | |
… | |
561 | .IP "ev_loop_fork (loop)" 4 |
648 | .IP "ev_loop_fork (loop)" 4 |
562 | .IX Item "ev_loop_fork (loop)" |
649 | .IX Item "ev_loop_fork (loop)" |
563 | Like \f(CW\*(C`ev_default_fork\*(C'\fR, but acts on an event loop created by |
650 | Like \f(CW\*(C`ev_default_fork\*(C'\fR, but acts on an event loop created by |
564 | \&\f(CW\*(C`ev_loop_new\*(C'\fR. Yes, you have to call this on every allocated event loop |
651 | \&\f(CW\*(C`ev_loop_new\*(C'\fR. Yes, you have to call this on every allocated event loop |
565 | after fork, and how you do this is entirely your own problem. |
652 | after fork, and how you do this is entirely your own problem. |
|
|
653 | .IP "unsigned int ev_loop_count (loop)" 4 |
|
|
654 | .IX Item "unsigned int ev_loop_count (loop)" |
|
|
655 | Returns the count of loop iterations for the loop, which is identical to |
|
|
656 | the number of times libev did poll for new events. It starts at \f(CW0\fR and |
|
|
657 | happily wraps around with enough iterations. |
|
|
658 | .Sp |
|
|
659 | This value can sometimes be useful as a generation counter of sorts (it |
|
|
660 | \&\*(L"ticks\*(R" the number of loop iterations), as it roughly corresponds with |
|
|
661 | \&\f(CW\*(C`ev_prepare\*(C'\fR and \f(CW\*(C`ev_check\*(C'\fR calls. |
566 | .IP "unsigned int ev_backend (loop)" 4 |
662 | .IP "unsigned int ev_backend (loop)" 4 |
567 | .IX Item "unsigned int ev_backend (loop)" |
663 | .IX Item "unsigned int ev_backend (loop)" |
568 | Returns one of the \f(CW\*(C`EVBACKEND_*\*(C'\fR flags indicating the event backend in |
664 | Returns one of the \f(CW\*(C`EVBACKEND_*\*(C'\fR flags indicating the event backend in |
569 | use. |
665 | use. |
570 | .IP "ev_tstamp ev_now (loop)" 4 |
666 | .IP "ev_tstamp ev_now (loop)" 4 |
571 | .IX Item "ev_tstamp ev_now (loop)" |
667 | .IX Item "ev_tstamp ev_now (loop)" |
572 | Returns the current \*(L"event loop time\*(R", which is the time the event loop |
668 | Returns the current \*(L"event loop time\*(R", which is the time the event loop |
573 | received events and started processing them. This timestamp does not |
669 | received events and started processing them. This timestamp does not |
574 | change as long as callbacks are being processed, and this is also the base |
670 | change as long as callbacks are being processed, and this is also the base |
575 | time used for relative timers. You can treat it as the timestamp of the |
671 | time used for relative timers. You can treat it as the timestamp of the |
576 | event occuring (or more correctly, libev finding out about it). |
672 | event occurring (or more correctly, libev finding out about it). |
577 | .IP "ev_loop (loop, int flags)" 4 |
673 | .IP "ev_loop (loop, int flags)" 4 |
578 | .IX Item "ev_loop (loop, int flags)" |
674 | .IX Item "ev_loop (loop, int flags)" |
579 | Finally, this is it, the event handler. This function usually is called |
675 | Finally, this is it, the event handler. This function usually is called |
580 | after you initialised all your watchers and you want to start handling |
676 | after you initialised all your watchers and you want to start handling |
581 | events. |
677 | events. |
… | |
… | |
601 | libev watchers. However, a pair of \f(CW\*(C`ev_prepare\*(C'\fR/\f(CW\*(C`ev_check\*(C'\fR watchers is |
697 | libev watchers. However, a pair of \f(CW\*(C`ev_prepare\*(C'\fR/\f(CW\*(C`ev_check\*(C'\fR watchers is |
602 | usually a better approach for this kind of thing. |
698 | usually a better approach for this kind of thing. |
603 | .Sp |
699 | .Sp |
604 | Here are the gory details of what \f(CW\*(C`ev_loop\*(C'\fR does: |
700 | Here are the gory details of what \f(CW\*(C`ev_loop\*(C'\fR does: |
605 | .Sp |
701 | .Sp |
606 | .Vb 18 |
702 | .Vb 19 |
|
|
703 | \& - Before the first iteration, call any pending watchers. |
607 | \& * If there are no active watchers (reference count is zero), return. |
704 | \& * If there are no active watchers (reference count is zero), return. |
608 | \& - Queue prepare watchers and then call all outstanding watchers. |
705 | \& - Queue all prepare watchers and then call all outstanding watchers. |
609 | \& - If we have been forked, recreate the kernel state. |
706 | \& - If we have been forked, recreate the kernel state. |
610 | \& - Update the kernel state with all outstanding changes. |
707 | \& - Update the kernel state with all outstanding changes. |
611 | \& - Update the "event loop time". |
708 | \& - Update the "event loop time". |
612 | \& - Calculate for how long to block. |
709 | \& - Calculate for how long to block. |
613 | \& - Block the process, waiting for any events. |
710 | \& - Block the process, waiting for any events. |
… | |
… | |
670 | .Sp |
767 | .Sp |
671 | .Vb 2 |
768 | .Vb 2 |
672 | \& ev_ref (loop); |
769 | \& ev_ref (loop); |
673 | \& ev_signal_stop (loop, &exitsig); |
770 | \& ev_signal_stop (loop, &exitsig); |
674 | .Ve |
771 | .Ve |
|
|
772 | .IP "ev_set_io_collect_interval (loop, ev_tstamp interval)" 4 |
|
|
773 | .IX Item "ev_set_io_collect_interval (loop, ev_tstamp interval)" |
|
|
774 | .PD 0 |
|
|
775 | .IP "ev_set_timeout_collect_interval (loop, ev_tstamp interval)" 4 |
|
|
776 | .IX Item "ev_set_timeout_collect_interval (loop, ev_tstamp interval)" |
|
|
777 | .PD |
|
|
778 | These advanced functions influence the time that libev will spend waiting |
|
|
779 | for events. Both are by default \f(CW0\fR, meaning that libev will try to |
|
|
780 | invoke timer/periodic callbacks and I/O callbacks with minimum latency. |
|
|
781 | .Sp |
|
|
782 | Setting these to a higher value (the \f(CW\*(C`interval\*(C'\fR \fImust\fR be >= \f(CW0\fR) |
|
|
783 | allows libev to delay invocation of I/O and timer/periodic callbacks to |
|
|
784 | increase efficiency of loop iterations. |
|
|
785 | .Sp |
|
|
786 | The background is that sometimes your program runs just fast enough to |
|
|
787 | handle one (or very few) event(s) per loop iteration. While this makes |
|
|
788 | the program responsive, it also wastes a lot of \s-1CPU\s0 time to poll for new |
|
|
789 | events, especially with backends like \f(CW\*(C`select ()\*(C'\fR which have a high |
|
|
790 | overhead for the actual polling but can deliver many events at once. |
|
|
791 | .Sp |
|
|
792 | By setting a higher \fIio collect interval\fR you allow libev to spend more |
|
|
793 | time collecting I/O events, so you can handle more events per iteration, |
|
|
794 | at the cost of increasing latency. Timeouts (both \f(CW\*(C`ev_periodic\*(C'\fR and |
|
|
795 | \&\f(CW\*(C`ev_timer\*(C'\fR) will be not affected. Setting this to a non-null value will |
|
|
796 | introduce an additional \f(CW\*(C`ev_sleep ()\*(C'\fR call into most loop iterations. |
|
|
797 | .Sp |
|
|
798 | Likewise, by setting a higher \fItimeout collect interval\fR you allow libev |
|
|
799 | to spend more time collecting timeouts, at the expense of increased |
|
|
800 | latency (the watcher callback will be called later). \f(CW\*(C`ev_io\*(C'\fR watchers |
|
|
801 | will not be affected. Setting this to a non-null value will not introduce |
|
|
802 | any overhead in libev. |
|
|
803 | .Sp |
|
|
804 | Many (busy) programs can usually benefit by setting the io collect |
|
|
805 | interval to a value near \f(CW0.1\fR or so, which is often enough for |
|
|
806 | interactive servers (of course not for games), likewise for timeouts. It |
|
|
807 | usually doesn't make much sense to set it to a lower value than \f(CW0.01\fR, |
|
|
808 | as this approsaches the timing granularity of most systems. |
675 | .SH "ANATOMY OF A WATCHER" |
809 | .SH "ANATOMY OF A WATCHER" |
676 | .IX Header "ANATOMY OF A WATCHER" |
810 | .IX Header "ANATOMY OF A WATCHER" |
677 | A watcher is a structure that you create and register to record your |
811 | A watcher is a structure that you create and register to record your |
678 | interest in some event. For instance, if you want to wait for \s-1STDIN\s0 to |
812 | interest in some event. For instance, if you want to wait for \s-1STDIN\s0 to |
679 | become readable, you would create an \f(CW\*(C`ev_io\*(C'\fR watcher for that: |
813 | become readable, you would create an \f(CW\*(C`ev_io\*(C'\fR watcher for that: |
… | |
… | |
856 | .IP "bool ev_is_pending (ev_TYPE *watcher)" 4 |
990 | .IP "bool ev_is_pending (ev_TYPE *watcher)" 4 |
857 | .IX Item "bool ev_is_pending (ev_TYPE *watcher)" |
991 | .IX Item "bool ev_is_pending (ev_TYPE *watcher)" |
858 | Returns a true value iff the watcher is pending, (i.e. it has outstanding |
992 | Returns a true value iff the watcher is pending, (i.e. it has outstanding |
859 | events but its callback has not yet been invoked). As long as a watcher |
993 | events but its callback has not yet been invoked). As long as a watcher |
860 | is pending (but not active) you must not call an init function on it (but |
994 | is pending (but not active) you must not call an init function on it (but |
861 | \&\f(CW\*(C`ev_TYPE_set\*(C'\fR is safe) and you must make sure the watcher is available to |
995 | \&\f(CW\*(C`ev_TYPE_set\*(C'\fR is safe), you must not change its priority, and you must |
862 | libev (e.g. you cnanot \f(CW\*(C`free ()\*(C'\fR it). |
996 | make sure the watcher is available to libev (e.g. you cannot \f(CW\*(C`free ()\*(C'\fR |
|
|
997 | it). |
863 | .IP "callback ev_cb (ev_TYPE *watcher)" 4 |
998 | .IP "callback ev_cb (ev_TYPE *watcher)" 4 |
864 | .IX Item "callback ev_cb (ev_TYPE *watcher)" |
999 | .IX Item "callback ev_cb (ev_TYPE *watcher)" |
865 | Returns the callback currently set on the watcher. |
1000 | Returns the callback currently set on the watcher. |
866 | .IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 |
1001 | .IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 |
867 | .IX Item "ev_cb_set (ev_TYPE *watcher, callback)" |
1002 | .IX Item "ev_cb_set (ev_TYPE *watcher, callback)" |
868 | Change the callback. You can change the callback at virtually any time |
1003 | Change the callback. You can change the callback at virtually any time |
869 | (modulo threads). |
1004 | (modulo threads). |
|
|
1005 | .IP "ev_set_priority (ev_TYPE *watcher, priority)" 4 |
|
|
1006 | .IX Item "ev_set_priority (ev_TYPE *watcher, priority)" |
|
|
1007 | .PD 0 |
|
|
1008 | .IP "int ev_priority (ev_TYPE *watcher)" 4 |
|
|
1009 | .IX Item "int ev_priority (ev_TYPE *watcher)" |
|
|
1010 | .PD |
|
|
1011 | Set and query the priority of the watcher. The priority is a small |
|
|
1012 | integer between \f(CW\*(C`EV_MAXPRI\*(C'\fR (default: \f(CW2\fR) and \f(CW\*(C`EV_MINPRI\*(C'\fR |
|
|
1013 | (default: \f(CW\*(C`\-2\*(C'\fR). Pending watchers with higher priority will be invoked |
|
|
1014 | before watchers with lower priority, but priority will not keep watchers |
|
|
1015 | from being executed (except for \f(CW\*(C`ev_idle\*(C'\fR watchers). |
|
|
1016 | .Sp |
|
|
1017 | This means that priorities are \fIonly\fR used for ordering callback |
|
|
1018 | invocation after new events have been received. This is useful, for |
|
|
1019 | example, to reduce latency after idling, or more often, to bind two |
|
|
1020 | watchers on the same event and make sure one is called first. |
|
|
1021 | .Sp |
|
|
1022 | If you need to suppress invocation when higher priority events are pending |
|
|
1023 | you need to look at \f(CW\*(C`ev_idle\*(C'\fR watchers, which provide this functionality. |
|
|
1024 | .Sp |
|
|
1025 | You \fImust not\fR change the priority of a watcher as long as it is active or |
|
|
1026 | pending. |
|
|
1027 | .Sp |
|
|
1028 | The default priority used by watchers when no priority has been set is |
|
|
1029 | always \f(CW0\fR, which is supposed to not be too high and not be too low :). |
|
|
1030 | .Sp |
|
|
1031 | Setting a priority outside the range of \f(CW\*(C`EV_MINPRI\*(C'\fR to \f(CW\*(C`EV_MAXPRI\*(C'\fR is |
|
|
1032 | fine, as long as you do not mind that the priority value you query might |
|
|
1033 | or might not have been adjusted to be within valid range. |
|
|
1034 | .IP "ev_invoke (loop, ev_TYPE *watcher, int revents)" 4 |
|
|
1035 | .IX Item "ev_invoke (loop, ev_TYPE *watcher, int revents)" |
|
|
1036 | Invoke the \f(CW\*(C`watcher\*(C'\fR with the given \f(CW\*(C`loop\*(C'\fR and \f(CW\*(C`revents\*(C'\fR. Neither |
|
|
1037 | \&\f(CW\*(C`loop\*(C'\fR nor \f(CW\*(C`revents\*(C'\fR need to be valid as long as the watcher callback |
|
|
1038 | can deal with that fact. |
|
|
1039 | .IP "int ev_clear_pending (loop, ev_TYPE *watcher)" 4 |
|
|
1040 | .IX Item "int ev_clear_pending (loop, ev_TYPE *watcher)" |
|
|
1041 | If the watcher is pending, this function returns clears its pending status |
|
|
1042 | and returns its \f(CW\*(C`revents\*(C'\fR bitset (as if its callback was invoked). If the |
|
|
1043 | watcher isn't pending it does nothing and returns \f(CW0\fR. |
870 | .Sh "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0" |
1044 | .Sh "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0" |
871 | .IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER" |
1045 | .IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER" |
872 | Each watcher has, by default, a member \f(CW\*(C`void *data\*(C'\fR that you can change |
1046 | Each watcher has, by default, a member \f(CW\*(C`void *data\*(C'\fR that you can change |
873 | and read at any time, libev will completely ignore it. This can be used |
1047 | and read at any time, libev will completely ignore it. This can be used |
874 | to associate arbitrary data with your watcher. If you need more data and |
1048 | to associate arbitrary data with your watcher. If you need more data and |
… | |
… | |
964 | In general you can register as many read and/or write event watchers per |
1138 | In general you can register as many read and/or write event watchers per |
965 | fd as you want (as long as you don't confuse yourself). Setting all file |
1139 | fd as you want (as long as you don't confuse yourself). Setting all file |
966 | descriptors to non-blocking mode is also usually a good idea (but not |
1140 | descriptors to non-blocking mode is also usually a good idea (but not |
967 | required if you know what you are doing). |
1141 | required if you know what you are doing). |
968 | .PP |
1142 | .PP |
969 | You have to be careful with dup'ed file descriptors, though. Some backends |
|
|
970 | (the linux epoll backend is a notable example) cannot handle dup'ed file |
|
|
971 | descriptors correctly if you register interest in two or more fds pointing |
|
|
972 | to the same underlying file/socket/etc. description (that is, they share |
|
|
973 | the same underlying \*(L"file open\*(R"). |
|
|
974 | .PP |
|
|
975 | If you must do this, then force the use of a known-to-be-good backend |
1143 | If you must do this, then force the use of a known-to-be-good backend |
976 | (at the time of this writing, this includes only \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR and |
1144 | (at the time of this writing, this includes only \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR and |
977 | \&\f(CW\*(C`EVBACKEND_POLL\*(C'\fR). |
1145 | \&\f(CW\*(C`EVBACKEND_POLL\*(C'\fR). |
978 | .PP |
1146 | .PP |
979 | Another thing you have to watch out for is that it is quite easy to |
1147 | Another thing you have to watch out for is that it is quite easy to |
… | |
… | |
985 | it is best to always use non-blocking I/O: An extra \f(CW\*(C`read\*(C'\fR(2) returning |
1153 | it is best to always use non-blocking I/O: An extra \f(CW\*(C`read\*(C'\fR(2) returning |
986 | \&\f(CW\*(C`EAGAIN\*(C'\fR is far preferable to a program hanging until some data arrives. |
1154 | \&\f(CW\*(C`EAGAIN\*(C'\fR is far preferable to a program hanging until some data arrives. |
987 | .PP |
1155 | .PP |
988 | If you cannot run the fd in non-blocking mode (for example you should not |
1156 | If you cannot run the fd in non-blocking mode (for example you should not |
989 | play around with an Xlib connection), then you have to seperately re-test |
1157 | play around with an Xlib connection), then you have to seperately re-test |
990 | wether a file descriptor is really ready with a known-to-be good interface |
1158 | whether a file descriptor is really ready with a known-to-be good interface |
991 | such as poll (fortunately in our Xlib example, Xlib already does this on |
1159 | such as poll (fortunately in our Xlib example, Xlib already does this on |
992 | its own, so its quite safe to use). |
1160 | its own, so its quite safe to use). |
|
|
1161 | .PP |
|
|
1162 | \fIThe special problem of disappearing file descriptors\fR |
|
|
1163 | .IX Subsection "The special problem of disappearing file descriptors" |
|
|
1164 | .PP |
|
|
1165 | Some backends (e.g. kqueue, epoll) need to be told about closing a file |
|
|
1166 | descriptor (either by calling \f(CW\*(C`close\*(C'\fR explicitly or by any other means, |
|
|
1167 | such as \f(CW\*(C`dup\*(C'\fR). The reason is that you register interest in some file |
|
|
1168 | descriptor, but when it goes away, the operating system will silently drop |
|
|
1169 | this interest. If another file descriptor with the same number then is |
|
|
1170 | registered with libev, there is no efficient way to see that this is, in |
|
|
1171 | fact, a different file descriptor. |
|
|
1172 | .PP |
|
|
1173 | To avoid having to explicitly tell libev about such cases, libev follows |
|
|
1174 | the following policy: Each time \f(CW\*(C`ev_io_set\*(C'\fR is being called, libev |
|
|
1175 | will assume that this is potentially a new file descriptor, otherwise |
|
|
1176 | it is assumed that the file descriptor stays the same. That means that |
|
|
1177 | you \fIhave\fR to call \f(CW\*(C`ev_io_set\*(C'\fR (or \f(CW\*(C`ev_io_init\*(C'\fR) when you change the |
|
|
1178 | descriptor even if the file descriptor number itself did not change. |
|
|
1179 | .PP |
|
|
1180 | This is how one would do it normally anyway, the important point is that |
|
|
1181 | the libev application should not optimise around libev but should leave |
|
|
1182 | optimisations to libev. |
|
|
1183 | .PP |
|
|
1184 | \fIThe special problem of dup'ed file descriptors\fR |
|
|
1185 | .IX Subsection "The special problem of dup'ed file descriptors" |
|
|
1186 | .PP |
|
|
1187 | Some backends (e.g. epoll), cannot register events for file descriptors, |
|
|
1188 | but only events for the underlying file descriptions. That means when you |
|
|
1189 | have \f(CW\*(C`dup ()\*(C'\fR'ed file descriptors or weirder constellations, and register |
|
|
1190 | events for them, only one file descriptor might actually receive events. |
|
|
1191 | .PP |
|
|
1192 | There is no workaround possible except not registering events |
|
|
1193 | for potentially \f(CW\*(C`dup ()\*(C'\fR'ed file descriptors, or to resort to |
|
|
1194 | \&\f(CW\*(C`EVBACKEND_SELECT\*(C'\fR or \f(CW\*(C`EVBACKEND_POLL\*(C'\fR. |
|
|
1195 | .PP |
|
|
1196 | \fIThe special problem of fork\fR |
|
|
1197 | .IX Subsection "The special problem of fork" |
|
|
1198 | .PP |
|
|
1199 | Some backends (epoll, kqueue) do not support \f(CW\*(C`fork ()\*(C'\fR at all or exhibit |
|
|
1200 | useless behaviour. Libev fully supports fork, but needs to be told about |
|
|
1201 | it in the child. |
|
|
1202 | .PP |
|
|
1203 | To support fork in your programs, you either have to call |
|
|
1204 | \&\f(CW\*(C`ev_default_fork ()\*(C'\fR or \f(CW\*(C`ev_loop_fork ()\*(C'\fR after a fork in the child, |
|
|
1205 | enable \f(CW\*(C`EVFLAG_FORKCHECK\*(C'\fR, or resort to \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR or |
|
|
1206 | \&\f(CW\*(C`EVBACKEND_POLL\*(C'\fR. |
|
|
1207 | .PP |
|
|
1208 | \fIWatcher-Specific Functions\fR |
|
|
1209 | .IX Subsection "Watcher-Specific Functions" |
993 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
1210 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
994 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
1211 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
995 | .PD 0 |
1212 | .PD 0 |
996 | .IP "ev_io_set (ev_io *, int fd, int events)" 4 |
1213 | .IP "ev_io_set (ev_io *, int fd, int events)" 4 |
997 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
1214 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
… | |
… | |
1050 | .Ve |
1267 | .Ve |
1051 | .PP |
1268 | .PP |
1052 | The callback is guarenteed to be invoked only when its timeout has passed, |
1269 | The callback is guarenteed to be invoked only when its timeout has passed, |
1053 | but if multiple timers become ready during the same loop iteration then |
1270 | but if multiple timers become ready during the same loop iteration then |
1054 | order of execution is undefined. |
1271 | order of execution is undefined. |
|
|
1272 | .PP |
|
|
1273 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1274 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1055 | .IP "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" 4 |
1275 | .IP "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" 4 |
1056 | .IX Item "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" |
1276 | .IX Item "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" |
1057 | .PD 0 |
1277 | .PD 0 |
1058 | .IP "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)" 4 |
1278 | .IP "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)" 4 |
1059 | .IX Item "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)" |
1279 | .IX Item "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)" |
… | |
… | |
1071 | .IP "ev_timer_again (loop)" 4 |
1291 | .IP "ev_timer_again (loop)" 4 |
1072 | .IX Item "ev_timer_again (loop)" |
1292 | .IX Item "ev_timer_again (loop)" |
1073 | This will act as if the timer timed out and restart it again if it is |
1293 | This will act as if the timer timed out and restart it again if it is |
1074 | repeating. The exact semantics are: |
1294 | repeating. The exact semantics are: |
1075 | .Sp |
1295 | .Sp |
|
|
1296 | If the timer is pending, its pending status is cleared. |
|
|
1297 | .Sp |
1076 | If the timer is started but nonrepeating, stop it. |
1298 | If the timer is started but nonrepeating, stop it (as if it timed out). |
1077 | .Sp |
1299 | .Sp |
1078 | If the timer is repeating, either start it if necessary (with the repeat |
1300 | If the timer is repeating, either start it if necessary (with the |
1079 | value), or reset the running timer to the repeat value. |
1301 | \&\f(CW\*(C`repeat\*(C'\fR value), or reset the running timer to the \f(CW\*(C`repeat\*(C'\fR value. |
1080 | .Sp |
1302 | .Sp |
1081 | This sounds a bit complicated, but here is a useful and typical |
1303 | This sounds a bit complicated, but here is a useful and typical |
1082 | example: Imagine you have a tcp connection and you want a so-called |
1304 | example: Imagine you have a tcp connection and you want a so-called idle |
1083 | idle timeout, that is, you want to be called when there have been, |
1305 | timeout, that is, you want to be called when there have been, say, 60 |
1084 | say, 60 seconds of inactivity on the socket. The easiest way to do |
1306 | seconds of inactivity on the socket. The easiest way to do this is to |
1085 | this is to configure an \f(CW\*(C`ev_timer\*(C'\fR with \f(CW\*(C`after\*(C'\fR=\f(CW\*(C`repeat\*(C'\fR=\f(CW60\fR and calling |
1307 | configure an \f(CW\*(C`ev_timer\*(C'\fR with a \f(CW\*(C`repeat\*(C'\fR value of \f(CW60\fR and then call |
1086 | \&\f(CW\*(C`ev_timer_again\*(C'\fR each time you successfully read or write some data. If |
1308 | \&\f(CW\*(C`ev_timer_again\*(C'\fR each time you successfully read or write some data. If |
1087 | you go into an idle state where you do not expect data to travel on the |
1309 | you go into an idle state where you do not expect data to travel on the |
1088 | socket, you can stop the timer, and again will automatically restart it if |
1310 | socket, you can \f(CW\*(C`ev_timer_stop\*(C'\fR the timer, and \f(CW\*(C`ev_timer_again\*(C'\fR will |
1089 | need be. |
1311 | automatically restart it if need be. |
1090 | .Sp |
1312 | .Sp |
1091 | You can also ignore the \f(CW\*(C`after\*(C'\fR value and \f(CW\*(C`ev_timer_start\*(C'\fR altogether |
1313 | That means you can ignore the \f(CW\*(C`after\*(C'\fR value and \f(CW\*(C`ev_timer_start\*(C'\fR |
1092 | and only ever use the \f(CW\*(C`repeat\*(C'\fR value: |
1314 | altogether and only ever use the \f(CW\*(C`repeat\*(C'\fR value and \f(CW\*(C`ev_timer_again\*(C'\fR: |
1093 | .Sp |
1315 | .Sp |
1094 | .Vb 8 |
1316 | .Vb 8 |
1095 | \& ev_timer_init (timer, callback, 0., 5.); |
1317 | \& ev_timer_init (timer, callback, 0., 5.); |
1096 | \& ev_timer_again (loop, timer); |
1318 | \& ev_timer_again (loop, timer); |
1097 | \& ... |
1319 | \& ... |
… | |
… | |
1100 | \& ... |
1322 | \& ... |
1101 | \& timer->again = 10.; |
1323 | \& timer->again = 10.; |
1102 | \& ev_timer_again (loop, timer); |
1324 | \& ev_timer_again (loop, timer); |
1103 | .Ve |
1325 | .Ve |
1104 | .Sp |
1326 | .Sp |
1105 | This is more efficient then stopping/starting the timer eahc time you want |
1327 | This is more slightly efficient then stopping/starting the timer each time |
1106 | to modify its timeout value. |
1328 | you want to modify its timeout value. |
1107 | .IP "ev_tstamp repeat [read\-write]" 4 |
1329 | .IP "ev_tstamp repeat [read\-write]" 4 |
1108 | .IX Item "ev_tstamp repeat [read-write]" |
1330 | .IX Item "ev_tstamp repeat [read-write]" |
1109 | The current \f(CW\*(C`repeat\*(C'\fR value. Will be used each time the watcher times out |
1331 | The current \f(CW\*(C`repeat\*(C'\fR value. Will be used each time the watcher times out |
1110 | or \f(CW\*(C`ev_timer_again\*(C'\fR is called and determines the next timeout (if any), |
1332 | or \f(CW\*(C`ev_timer_again\*(C'\fR is called and determines the next timeout (if any), |
1111 | which is also when any modifications are taken into account. |
1333 | which is also when any modifications are taken into account. |
… | |
… | |
1159 | but on wallclock time (absolute time). You can tell a periodic watcher |
1381 | but on wallclock time (absolute time). You can tell a periodic watcher |
1160 | to trigger \*(L"at\*(R" some specific point in time. For example, if you tell a |
1382 | to trigger \*(L"at\*(R" some specific point in time. For example, if you tell a |
1161 | periodic watcher to trigger in 10 seconds (by specifiying e.g. \f(CW\*(C`ev_now () |
1383 | periodic watcher to trigger in 10 seconds (by specifiying e.g. \f(CW\*(C`ev_now () |
1162 | + 10.\*(C'\fR) and then reset your system clock to the last year, then it will |
1384 | + 10.\*(C'\fR) and then reset your system clock to the last year, then it will |
1163 | take a year to trigger the event (unlike an \f(CW\*(C`ev_timer\*(C'\fR, which would trigger |
1385 | take a year to trigger the event (unlike an \f(CW\*(C`ev_timer\*(C'\fR, which would trigger |
1164 | roughly 10 seconds later and of course not if you reset your system time |
1386 | roughly 10 seconds later). |
1165 | again). |
|
|
1166 | .PP |
1387 | .PP |
1167 | They can also be used to implement vastly more complex timers, such as |
1388 | They can also be used to implement vastly more complex timers, such as |
1168 | triggering an event on eahc midnight, local time. |
1389 | triggering an event on each midnight, local time or other, complicated, |
|
|
1390 | rules. |
1169 | .PP |
1391 | .PP |
1170 | As with timers, the callback is guarenteed to be invoked only when the |
1392 | As with timers, the callback is guarenteed to be invoked only when the |
1171 | time (\f(CW\*(C`at\*(C'\fR) has been passed, but if multiple periodic timers become ready |
1393 | time (\f(CW\*(C`at\*(C'\fR) has been passed, but if multiple periodic timers become ready |
1172 | during the same loop iteration then order of execution is undefined. |
1394 | during the same loop iteration then order of execution is undefined. |
|
|
1395 | .PP |
|
|
1396 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1397 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1173 | .IP "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" 4 |
1398 | .IP "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" 4 |
1174 | .IX Item "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" |
1399 | .IX Item "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" |
1175 | .PD 0 |
1400 | .PD 0 |
1176 | .IP "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" 4 |
1401 | .IP "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" 4 |
1177 | .IX Item "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" |
1402 | .IX Item "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" |
1178 | .PD |
1403 | .PD |
1179 | Lots of arguments, lets sort it out... There are basically three modes of |
1404 | Lots of arguments, lets sort it out... There are basically three modes of |
1180 | operation, and we will explain them from simplest to complex: |
1405 | operation, and we will explain them from simplest to complex: |
1181 | .RS 4 |
1406 | .RS 4 |
1182 | .IP "* absolute timer (interval = reschedule_cb = 0)" 4 |
1407 | .IP "* absolute timer (at = time, interval = reschedule_cb = 0)" 4 |
1183 | .IX Item "absolute timer (interval = reschedule_cb = 0)" |
1408 | .IX Item "absolute timer (at = time, interval = reschedule_cb = 0)" |
1184 | In this configuration the watcher triggers an event at the wallclock time |
1409 | In this configuration the watcher triggers an event at the wallclock time |
1185 | \&\f(CW\*(C`at\*(C'\fR and doesn't repeat. It will not adjust when a time jump occurs, |
1410 | \&\f(CW\*(C`at\*(C'\fR and doesn't repeat. It will not adjust when a time jump occurs, |
1186 | that is, if it is to be run at January 1st 2011 then it will run when the |
1411 | that is, if it is to be run at January 1st 2011 then it will run when the |
1187 | system time reaches or surpasses this time. |
1412 | system time reaches or surpasses this time. |
1188 | .IP "* non-repeating interval timer (interval > 0, reschedule_cb = 0)" 4 |
1413 | .IP "* non-repeating interval timer (at = offset, interval > 0, reschedule_cb = 0)" 4 |
1189 | .IX Item "non-repeating interval timer (interval > 0, reschedule_cb = 0)" |
1414 | .IX Item "non-repeating interval timer (at = offset, interval > 0, reschedule_cb = 0)" |
1190 | In this mode the watcher will always be scheduled to time out at the next |
1415 | In this mode the watcher will always be scheduled to time out at the next |
1191 | \&\f(CW\*(C`at + N * interval\*(C'\fR time (for some integer N) and then repeat, regardless |
1416 | \&\f(CW\*(C`at + N * interval\*(C'\fR time (for some integer N, which can also be negative) |
1192 | of any time jumps. |
1417 | and then repeat, regardless of any time jumps. |
1193 | .Sp |
1418 | .Sp |
1194 | This can be used to create timers that do not drift with respect to system |
1419 | This can be used to create timers that do not drift with respect to system |
1195 | time: |
1420 | time: |
1196 | .Sp |
1421 | .Sp |
1197 | .Vb 1 |
1422 | .Vb 1 |
… | |
… | |
1204 | by 3600. |
1429 | by 3600. |
1205 | .Sp |
1430 | .Sp |
1206 | Another way to think about it (for the mathematically inclined) is that |
1431 | Another way to think about it (for the mathematically inclined) is that |
1207 | \&\f(CW\*(C`ev_periodic\*(C'\fR will try to run the callback in this mode at the next possible |
1432 | \&\f(CW\*(C`ev_periodic\*(C'\fR will try to run the callback in this mode at the next possible |
1208 | time where \f(CW\*(C`time = at (mod interval)\*(C'\fR, regardless of any time jumps. |
1433 | time where \f(CW\*(C`time = at (mod interval)\*(C'\fR, regardless of any time jumps. |
|
|
1434 | .Sp |
|
|
1435 | For numerical stability it is preferable that the \f(CW\*(C`at\*(C'\fR value is near |
|
|
1436 | \&\f(CW\*(C`ev_now ()\*(C'\fR (the current time), but there is no range requirement for |
|
|
1437 | this value. |
1209 | .IP "* manual reschedule mode (reschedule_cb = callback)" 4 |
1438 | .IP "* manual reschedule mode (at and interval ignored, reschedule_cb = callback)" 4 |
1210 | .IX Item "manual reschedule mode (reschedule_cb = callback)" |
1439 | .IX Item "manual reschedule mode (at and interval ignored, reschedule_cb = callback)" |
1211 | In this mode the values for \f(CW\*(C`interval\*(C'\fR and \f(CW\*(C`at\*(C'\fR are both being |
1440 | In this mode the values for \f(CW\*(C`interval\*(C'\fR and \f(CW\*(C`at\*(C'\fR are both being |
1212 | ignored. Instead, each time the periodic watcher gets scheduled, the |
1441 | ignored. Instead, each time the periodic watcher gets scheduled, the |
1213 | reschedule callback will be called with the watcher as first, and the |
1442 | reschedule callback will be called with the watcher as first, and the |
1214 | current time as second argument. |
1443 | current time as second argument. |
1215 | .Sp |
1444 | .Sp |
1216 | \&\s-1NOTE:\s0 \fIThis callback \s-1MUST\s0 \s-1NOT\s0 stop or destroy any periodic watcher, |
1445 | \&\s-1NOTE:\s0 \fIThis callback \s-1MUST\s0 \s-1NOT\s0 stop or destroy any periodic watcher, |
1217 | ever, or make any event loop modifications\fR. If you need to stop it, |
1446 | ever, or make any event loop modifications\fR. If you need to stop it, |
1218 | return \f(CW\*(C`now + 1e30\*(C'\fR (or so, fudge fudge) and stop it afterwards (e.g. by |
1447 | return \f(CW\*(C`now + 1e30\*(C'\fR (or so, fudge fudge) and stop it afterwards (e.g. by |
1219 | starting a prepare watcher). |
1448 | starting an \f(CW\*(C`ev_prepare\*(C'\fR watcher, which is legal). |
1220 | .Sp |
1449 | .Sp |
1221 | Its prototype is \f(CW\*(C`ev_tstamp (*reschedule_cb)(struct ev_periodic *w, |
1450 | Its prototype is \f(CW\*(C`ev_tstamp (*reschedule_cb)(struct ev_periodic *w, |
1222 | ev_tstamp now)\*(C'\fR, e.g.: |
1451 | ev_tstamp now)\*(C'\fR, e.g.: |
1223 | .Sp |
1452 | .Sp |
1224 | .Vb 4 |
1453 | .Vb 4 |
… | |
… | |
1248 | .IX Item "ev_periodic_again (loop, ev_periodic *)" |
1477 | .IX Item "ev_periodic_again (loop, ev_periodic *)" |
1249 | Simply stops and restarts the periodic watcher again. This is only useful |
1478 | Simply stops and restarts the periodic watcher again. This is only useful |
1250 | when you changed some parameters or the reschedule callback would return |
1479 | when you changed some parameters or the reschedule callback would return |
1251 | a different time than the last time it was called (e.g. in a crond like |
1480 | a different time than the last time it was called (e.g. in a crond like |
1252 | program when the crontabs have changed). |
1481 | program when the crontabs have changed). |
|
|
1482 | .IP "ev_tstamp offset [read\-write]" 4 |
|
|
1483 | .IX Item "ev_tstamp offset [read-write]" |
|
|
1484 | When repeating, this contains the offset value, otherwise this is the |
|
|
1485 | absolute point in time (the \f(CW\*(C`at\*(C'\fR value passed to \f(CW\*(C`ev_periodic_set\*(C'\fR). |
|
|
1486 | .Sp |
|
|
1487 | Can be modified any time, but changes only take effect when the periodic |
|
|
1488 | timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called. |
1253 | .IP "ev_tstamp interval [read\-write]" 4 |
1489 | .IP "ev_tstamp interval [read\-write]" 4 |
1254 | .IX Item "ev_tstamp interval [read-write]" |
1490 | .IX Item "ev_tstamp interval [read-write]" |
1255 | The current interval value. Can be modified any time, but changes only |
1491 | The current interval value. Can be modified any time, but changes only |
1256 | take effect when the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being |
1492 | take effect when the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being |
1257 | called. |
1493 | called. |
1258 | .IP "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read\-write]" 4 |
1494 | .IP "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read\-write]" 4 |
1259 | .IX Item "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write]" |
1495 | .IX Item "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write]" |
1260 | The current reschedule callback, or \f(CW0\fR, if this functionality is |
1496 | The current reschedule callback, or \f(CW0\fR, if this functionality is |
1261 | switched off. Can be changed any time, but changes only take effect when |
1497 | switched off. Can be changed any time, but changes only take effect when |
1262 | the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called. |
1498 | the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called. |
|
|
1499 | .IP "ev_tstamp at [read\-only]" 4 |
|
|
1500 | .IX Item "ev_tstamp at [read-only]" |
|
|
1501 | When active, contains the absolute time that the watcher is supposed to |
|
|
1502 | trigger next. |
1263 | .PP |
1503 | .PP |
1264 | Example: Call a callback every hour, or, more precisely, whenever the |
1504 | Example: Call a callback every hour, or, more precisely, whenever the |
1265 | system clock is divisible by 3600. The callback invocation times have |
1505 | system clock is divisible by 3600. The callback invocation times have |
1266 | potentially a lot of jittering, but good long-term stability. |
1506 | potentially a lot of jittering, but good long-term stability. |
1267 | .PP |
1507 | .PP |
… | |
… | |
1317 | first watcher gets started will libev actually register a signal watcher |
1557 | first watcher gets started will libev actually register a signal watcher |
1318 | with the kernel (thus it coexists with your own signal handlers as long |
1558 | with the kernel (thus it coexists with your own signal handlers as long |
1319 | as you don't register any with libev). Similarly, when the last signal |
1559 | as you don't register any with libev). Similarly, when the last signal |
1320 | watcher for a signal is stopped libev will reset the signal handler to |
1560 | watcher for a signal is stopped libev will reset the signal handler to |
1321 | \&\s-1SIG_DFL\s0 (regardless of what it was set to before). |
1561 | \&\s-1SIG_DFL\s0 (regardless of what it was set to before). |
|
|
1562 | .PP |
|
|
1563 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1564 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1322 | .IP "ev_signal_init (ev_signal *, callback, int signum)" 4 |
1565 | .IP "ev_signal_init (ev_signal *, callback, int signum)" 4 |
1323 | .IX Item "ev_signal_init (ev_signal *, callback, int signum)" |
1566 | .IX Item "ev_signal_init (ev_signal *, callback, int signum)" |
1324 | .PD 0 |
1567 | .PD 0 |
1325 | .IP "ev_signal_set (ev_signal *, int signum)" 4 |
1568 | .IP "ev_signal_set (ev_signal *, int signum)" 4 |
1326 | .IX Item "ev_signal_set (ev_signal *, int signum)" |
1569 | .IX Item "ev_signal_set (ev_signal *, int signum)" |
… | |
… | |
1333 | .ie n .Sh """ev_child"" \- watch out for process status changes" |
1576 | .ie n .Sh """ev_child"" \- watch out for process status changes" |
1334 | .el .Sh "\f(CWev_child\fP \- watch out for process status changes" |
1577 | .el .Sh "\f(CWev_child\fP \- watch out for process status changes" |
1335 | .IX Subsection "ev_child - watch out for process status changes" |
1578 | .IX Subsection "ev_child - watch out for process status changes" |
1336 | Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to |
1579 | Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to |
1337 | some child status changes (most typically when a child of yours dies). |
1580 | some child status changes (most typically when a child of yours dies). |
|
|
1581 | .PP |
|
|
1582 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1583 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1338 | .IP "ev_child_init (ev_child *, callback, int pid)" 4 |
1584 | .IP "ev_child_init (ev_child *, callback, int pid)" 4 |
1339 | .IX Item "ev_child_init (ev_child *, callback, int pid)" |
1585 | .IX Item "ev_child_init (ev_child *, callback, int pid)" |
1340 | .PD 0 |
1586 | .PD 0 |
1341 | .IP "ev_child_set (ev_child *, int pid)" 4 |
1587 | .IP "ev_child_set (ev_child *, int pid)" 4 |
1342 | .IX Item "ev_child_set (ev_child *, int pid)" |
1588 | .IX Item "ev_child_set (ev_child *, int pid)" |
… | |
… | |
1407 | reader). Inotify will be used to give hints only and should not change the |
1653 | reader). Inotify will be used to give hints only and should not change the |
1408 | semantics of \f(CW\*(C`ev_stat\*(C'\fR watchers, which means that libev sometimes needs |
1654 | semantics of \f(CW\*(C`ev_stat\*(C'\fR watchers, which means that libev sometimes needs |
1409 | to fall back to regular polling again even with inotify, but changes are |
1655 | to fall back to regular polling again even with inotify, but changes are |
1410 | usually detected immediately, and if the file exists there will be no |
1656 | usually detected immediately, and if the file exists there will be no |
1411 | polling. |
1657 | polling. |
|
|
1658 | .PP |
|
|
1659 | \fIInotify\fR |
|
|
1660 | .IX Subsection "Inotify" |
|
|
1661 | .PP |
|
|
1662 | When \f(CW\*(C`inotify (7)\*(C'\fR support has been compiled into libev (generally only |
|
|
1663 | available on Linux) and present at runtime, it will be used to speed up |
|
|
1664 | change detection where possible. The inotify descriptor will be created lazily |
|
|
1665 | when the first \f(CW\*(C`ev_stat\*(C'\fR watcher is being started. |
|
|
1666 | .PP |
|
|
1667 | Inotify presense does not change the semantics of \f(CW\*(C`ev_stat\*(C'\fR watchers |
|
|
1668 | except that changes might be detected earlier, and in some cases, to avoid |
|
|
1669 | making regular \f(CW\*(C`stat\*(C'\fR calls. Even in the presense of inotify support |
|
|
1670 | there are many cases where libev has to resort to regular \f(CW\*(C`stat\*(C'\fR polling. |
|
|
1671 | .PP |
|
|
1672 | (There is no support for kqueue, as apparently it cannot be used to |
|
|
1673 | implement this functionality, due to the requirement of having a file |
|
|
1674 | descriptor open on the object at all times). |
|
|
1675 | .PP |
|
|
1676 | \fIThe special problem of stat time resolution\fR |
|
|
1677 | .IX Subsection "The special problem of stat time resolution" |
|
|
1678 | .PP |
|
|
1679 | The \f(CW\*(C`stat ()\*(C'\fR syscall only supports full-second resolution portably, and |
|
|
1680 | even on systems where the resolution is higher, many filesystems still |
|
|
1681 | only support whole seconds. |
|
|
1682 | .PP |
|
|
1683 | That means that, if the time is the only thing that changes, you might |
|
|
1684 | miss updates: on the first update, \f(CW\*(C`ev_stat\*(C'\fR detects a change and calls |
|
|
1685 | your callback, which does something. When there is another update within |
|
|
1686 | the same second, \f(CW\*(C`ev_stat\*(C'\fR will be unable to detect it. |
|
|
1687 | .PP |
|
|
1688 | The solution to this is to delay acting on a change for a second (or till |
|
|
1689 | the next second boundary), using a roughly one-second delay \f(CW\*(C`ev_timer\*(C'\fR |
|
|
1690 | (\f(CW\*(C`ev_timer_set (w, 0., 1.01); ev_timer_again (loop, w)\*(C'\fR). The \f(CW.01\fR |
|
|
1691 | is added to work around small timing inconsistencies of some operating |
|
|
1692 | systems. |
|
|
1693 | .PP |
|
|
1694 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1695 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1412 | .IP "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" 4 |
1696 | .IP "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" 4 |
1413 | .IX Item "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" |
1697 | .IX Item "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" |
1414 | .PD 0 |
1698 | .PD 0 |
1415 | .IP "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" 4 |
1699 | .IP "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" 4 |
1416 | .IX Item "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" |
1700 | .IX Item "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" |
… | |
… | |
1445 | The specified interval. |
1729 | The specified interval. |
1446 | .IP "const char *path [read\-only]" 4 |
1730 | .IP "const char *path [read\-only]" 4 |
1447 | .IX Item "const char *path [read-only]" |
1731 | .IX Item "const char *path [read-only]" |
1448 | The filesystem path that is being watched. |
1732 | The filesystem path that is being watched. |
1449 | .PP |
1733 | .PP |
|
|
1734 | \fIExamples\fR |
|
|
1735 | .IX Subsection "Examples" |
|
|
1736 | .PP |
1450 | Example: Watch \f(CW\*(C`/etc/passwd\*(C'\fR for attribute changes. |
1737 | Example: Watch \f(CW\*(C`/etc/passwd\*(C'\fR for attribute changes. |
1451 | .PP |
1738 | .PP |
1452 | .Vb 15 |
1739 | .Vb 15 |
1453 | \& static void |
1740 | \& static void |
1454 | \& passwd_cb (struct ev_loop *loop, ev_stat *w, int revents) |
1741 | \& passwd_cb (struct ev_loop *loop, ev_stat *w, int revents) |
… | |
… | |
1471 | \& ... |
1758 | \& ... |
1472 | \& ev_stat passwd; |
1759 | \& ev_stat passwd; |
1473 | .Ve |
1760 | .Ve |
1474 | .PP |
1761 | .PP |
1475 | .Vb 2 |
1762 | .Vb 2 |
1476 | \& ev_stat_init (&passwd, passwd_cb, "/etc/passwd"); |
1763 | \& ev_stat_init (&passwd, passwd_cb, "/etc/passwd", 0.); |
1477 | \& ev_stat_start (loop, &passwd); |
1764 | \& ev_stat_start (loop, &passwd); |
|
|
1765 | .Ve |
|
|
1766 | .PP |
|
|
1767 | Example: Like above, but additionally use a one-second delay so we do not |
|
|
1768 | miss updates (however, frequent updates will delay processing, too, so |
|
|
1769 | one might do the work both on \f(CW\*(C`ev_stat\*(C'\fR callback invocation \fIand\fR on |
|
|
1770 | \&\f(CW\*(C`ev_timer\*(C'\fR callback invocation). |
|
|
1771 | .PP |
|
|
1772 | .Vb 2 |
|
|
1773 | \& static ev_stat passwd; |
|
|
1774 | \& static ev_timer timer; |
|
|
1775 | .Ve |
|
|
1776 | .PP |
|
|
1777 | .Vb 4 |
|
|
1778 | \& static void |
|
|
1779 | \& timer_cb (EV_P_ ev_timer *w, int revents) |
|
|
1780 | \& { |
|
|
1781 | \& ev_timer_stop (EV_A_ w); |
|
|
1782 | .Ve |
|
|
1783 | .PP |
|
|
1784 | .Vb 2 |
|
|
1785 | \& /* now it's one second after the most recent passwd change */ |
|
|
1786 | \& } |
|
|
1787 | .Ve |
|
|
1788 | .PP |
|
|
1789 | .Vb 6 |
|
|
1790 | \& static void |
|
|
1791 | \& stat_cb (EV_P_ ev_stat *w, int revents) |
|
|
1792 | \& { |
|
|
1793 | \& /* reset the one-second timer */ |
|
|
1794 | \& ev_timer_again (EV_A_ &timer); |
|
|
1795 | \& } |
|
|
1796 | .Ve |
|
|
1797 | .PP |
|
|
1798 | .Vb 4 |
|
|
1799 | \& ... |
|
|
1800 | \& ev_stat_init (&passwd, stat_cb, "/etc/passwd", 0.); |
|
|
1801 | \& ev_stat_start (loop, &passwd); |
|
|
1802 | \& ev_timer_init (&timer, timer_cb, 0., 1.01); |
1478 | .Ve |
1803 | .Ve |
1479 | .ie n .Sh """ev_idle"" \- when you've got nothing better to do..." |
1804 | .ie n .Sh """ev_idle"" \- when you've got nothing better to do..." |
1480 | .el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do..." |
1805 | .el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do..." |
1481 | .IX Subsection "ev_idle - when you've got nothing better to do..." |
1806 | .IX Subsection "ev_idle - when you've got nothing better to do..." |
1482 | Idle watchers trigger events when there are no other events are pending |
1807 | Idle watchers trigger events when no other events of the same or higher |
1483 | (prepare, check and other idle watchers do not count). That is, as long |
1808 | priority are pending (prepare, check and other idle watchers do not |
1484 | as your process is busy handling sockets or timeouts (or even signals, |
1809 | count). |
1485 | imagine) it will not be triggered. But when your process is idle all idle |
1810 | .PP |
1486 | watchers are being called again and again, once per event loop iteration \- |
1811 | That is, as long as your process is busy handling sockets or timeouts |
|
|
1812 | (or even signals, imagine) of the same or higher priority it will not be |
|
|
1813 | triggered. But when your process is idle (or only lower-priority watchers |
|
|
1814 | are pending), the idle watchers are being called once per event loop |
1487 | until stopped, that is, or your process receives more events and becomes |
1815 | iteration \- until stopped, that is, or your process receives more events |
1488 | busy. |
1816 | and becomes busy again with higher priority stuff. |
1489 | .PP |
1817 | .PP |
1490 | The most noteworthy effect is that as long as any idle watchers are |
1818 | The most noteworthy effect is that as long as any idle watchers are |
1491 | active, the process will not block when waiting for new events. |
1819 | active, the process will not block when waiting for new events. |
1492 | .PP |
1820 | .PP |
1493 | Apart from keeping your process non-blocking (which is a useful |
1821 | Apart from keeping your process non-blocking (which is a useful |
1494 | effect on its own sometimes), idle watchers are a good place to do |
1822 | effect on its own sometimes), idle watchers are a good place to do |
1495 | \&\*(L"pseudo\-background processing\*(R", or delay processing stuff to after the |
1823 | \&\*(L"pseudo\-background processing\*(R", or delay processing stuff to after the |
1496 | event loop has handled all outstanding events. |
1824 | event loop has handled all outstanding events. |
|
|
1825 | .PP |
|
|
1826 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1827 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1497 | .IP "ev_idle_init (ev_signal *, callback)" 4 |
1828 | .IP "ev_idle_init (ev_signal *, callback)" 4 |
1498 | .IX Item "ev_idle_init (ev_signal *, callback)" |
1829 | .IX Item "ev_idle_init (ev_signal *, callback)" |
1499 | Initialises and configures the idle watcher \- it has no parameters of any |
1830 | Initialises and configures the idle watcher \- it has no parameters of any |
1500 | kind. There is a \f(CW\*(C`ev_idle_set\*(C'\fR macro, but using it is utterly pointless, |
1831 | kind. There is a \f(CW\*(C`ev_idle_set\*(C'\fR macro, but using it is utterly pointless, |
1501 | believe me. |
1832 | believe me. |
… | |
… | |
1556 | are ready to run (it's actually more complicated: it only runs coroutines |
1887 | are ready to run (it's actually more complicated: it only runs coroutines |
1557 | with priority higher than or equal to the event loop and one coroutine |
1888 | with priority higher than or equal to the event loop and one coroutine |
1558 | of lower priority, but only once, using idle watchers to keep the event |
1889 | of lower priority, but only once, using idle watchers to keep the event |
1559 | loop from blocking if lower-priority coroutines are active, thus mapping |
1890 | loop from blocking if lower-priority coroutines are active, thus mapping |
1560 | low-priority coroutines to idle/background tasks). |
1891 | low-priority coroutines to idle/background tasks). |
|
|
1892 | .PP |
|
|
1893 | It is recommended to give \f(CW\*(C`ev_check\*(C'\fR watchers highest (\f(CW\*(C`EV_MAXPRI\*(C'\fR) |
|
|
1894 | priority, to ensure that they are being run before any other watchers |
|
|
1895 | after the poll. Also, \f(CW\*(C`ev_check\*(C'\fR watchers (and \f(CW\*(C`ev_prepare\*(C'\fR watchers, |
|
|
1896 | too) should not activate (\*(L"feed\*(R") events into libev. While libev fully |
|
|
1897 | supports this, they will be called before other \f(CW\*(C`ev_check\*(C'\fR watchers |
|
|
1898 | did their job. As \f(CW\*(C`ev_check\*(C'\fR watchers are often used to embed other |
|
|
1899 | (non\-libev) event loops those other event loops might be in an unusable |
|
|
1900 | state until their \f(CW\*(C`ev_check\*(C'\fR watcher ran (always remind yourself to |
|
|
1901 | coexist peacefully with others). |
|
|
1902 | .PP |
|
|
1903 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1904 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1561 | .IP "ev_prepare_init (ev_prepare *, callback)" 4 |
1905 | .IP "ev_prepare_init (ev_prepare *, callback)" 4 |
1562 | .IX Item "ev_prepare_init (ev_prepare *, callback)" |
1906 | .IX Item "ev_prepare_init (ev_prepare *, callback)" |
1563 | .PD 0 |
1907 | .PD 0 |
1564 | .IP "ev_check_init (ev_check *, callback)" 4 |
1908 | .IP "ev_check_init (ev_check *, callback)" 4 |
1565 | .IX Item "ev_check_init (ev_check *, callback)" |
1909 | .IX Item "ev_check_init (ev_check *, callback)" |
1566 | .PD |
1910 | .PD |
1567 | Initialises and configures the prepare or check watcher \- they have no |
1911 | Initialises and configures the prepare or check watcher \- they have no |
1568 | parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR |
1912 | parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR |
1569 | macros, but using them is utterly, utterly and completely pointless. |
1913 | macros, but using them is utterly, utterly and completely pointless. |
1570 | .PP |
1914 | .PP |
1571 | Example: To include a library such as adns, you would add \s-1IO\s0 watchers |
1915 | There are a number of principal ways to embed other event loops or modules |
1572 | and a timeout watcher in a prepare handler, as required by libadns, and |
1916 | into libev. Here are some ideas on how to include libadns into libev |
|
|
1917 | (there is a Perl module named \f(CW\*(C`EV::ADNS\*(C'\fR that does this, which you could |
|
|
1918 | use for an actually working example. Another Perl module named \f(CW\*(C`EV::Glib\*(C'\fR |
|
|
1919 | embeds a Glib main context into libev, and finally, \f(CW\*(C`Glib::EV\*(C'\fR embeds \s-1EV\s0 |
|
|
1920 | into the Glib event loop). |
|
|
1921 | .PP |
|
|
1922 | Method 1: Add \s-1IO\s0 watchers and a timeout watcher in a prepare handler, |
1573 | in a check watcher, destroy them and call into libadns. What follows is |
1923 | and in a check watcher, destroy them and call into libadns. What follows |
1574 | pseudo-code only of course: |
1924 | is pseudo-code only of course. This requires you to either use a low |
|
|
1925 | priority for the check watcher or use \f(CW\*(C`ev_clear_pending\*(C'\fR explicitly, as |
|
|
1926 | the callbacks for the IO/timeout watchers might not have been called yet. |
1575 | .PP |
1927 | .PP |
1576 | .Vb 2 |
1928 | .Vb 2 |
1577 | \& static ev_io iow [nfd]; |
1929 | \& static ev_io iow [nfd]; |
1578 | \& static ev_timer tw; |
1930 | \& static ev_timer tw; |
1579 | .Ve |
1931 | .Ve |
1580 | .PP |
1932 | .PP |
1581 | .Vb 9 |
1933 | .Vb 4 |
1582 | \& static void |
1934 | \& static void |
1583 | \& io_cb (ev_loop *loop, ev_io *w, int revents) |
1935 | \& io_cb (ev_loop *loop, ev_io *w, int revents) |
1584 | \& { |
1936 | \& { |
1585 | \& // set the relevant poll flags |
|
|
1586 | \& // could also call adns_processreadable etc. here |
|
|
1587 | \& struct pollfd *fd = (struct pollfd *)w->data; |
|
|
1588 | \& if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
|
|
1589 | \& if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
|
|
1590 | \& } |
1937 | \& } |
1591 | .Ve |
1938 | .Ve |
1592 | .PP |
1939 | .PP |
1593 | .Vb 7 |
1940 | .Vb 8 |
1594 | \& // create io watchers for each fd and a timer before blocking |
1941 | \& // create io watchers for each fd and a timer before blocking |
1595 | \& static void |
1942 | \& static void |
1596 | \& adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
1943 | \& adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
1597 | \& { |
1944 | \& { |
1598 | \& int timeout = 3600000;truct pollfd fds [nfd]; |
1945 | \& int timeout = 3600000; |
|
|
1946 | \& struct pollfd fds [nfd]; |
1599 | \& // actual code will need to loop here and realloc etc. |
1947 | \& // actual code will need to loop here and realloc etc. |
1600 | \& adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
1948 | \& adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
1601 | .Ve |
1949 | .Ve |
1602 | .PP |
1950 | .PP |
1603 | .Vb 3 |
1951 | .Vb 3 |
… | |
… | |
1605 | \& ev_timer_init (&tw, 0, timeout * 1e-3); |
1953 | \& ev_timer_init (&tw, 0, timeout * 1e-3); |
1606 | \& ev_timer_start (loop, &tw); |
1954 | \& ev_timer_start (loop, &tw); |
1607 | .Ve |
1955 | .Ve |
1608 | .PP |
1956 | .PP |
1609 | .Vb 6 |
1957 | .Vb 6 |
1610 | \& // create on ev_io per pollfd |
1958 | \& // create one ev_io per pollfd |
1611 | \& for (int i = 0; i < nfd; ++i) |
1959 | \& for (int i = 0; i < nfd; ++i) |
1612 | \& { |
1960 | \& { |
1613 | \& ev_io_init (iow + i, io_cb, fds [i].fd, |
1961 | \& ev_io_init (iow + i, io_cb, fds [i].fd, |
1614 | \& ((fds [i].events & POLLIN ? EV_READ : 0) |
1962 | \& ((fds [i].events & POLLIN ? EV_READ : 0) |
1615 | \& | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
1963 | \& | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
1616 | .Ve |
1964 | .Ve |
1617 | .PP |
1965 | .PP |
1618 | .Vb 5 |
1966 | .Vb 4 |
1619 | \& fds [i].revents = 0; |
1967 | \& fds [i].revents = 0; |
1620 | \& iow [i].data = fds + i; |
|
|
1621 | \& ev_io_start (loop, iow + i); |
1968 | \& ev_io_start (loop, iow + i); |
1622 | \& } |
1969 | \& } |
1623 | \& } |
1970 | \& } |
1624 | .Ve |
1971 | .Ve |
1625 | .PP |
1972 | .PP |
… | |
… | |
1629 | \& adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
1976 | \& adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
1630 | \& { |
1977 | \& { |
1631 | \& ev_timer_stop (loop, &tw); |
1978 | \& ev_timer_stop (loop, &tw); |
1632 | .Ve |
1979 | .Ve |
1633 | .PP |
1980 | .PP |
1634 | .Vb 2 |
1981 | .Vb 8 |
1635 | \& for (int i = 0; i < nfd; ++i) |
1982 | \& for (int i = 0; i < nfd; ++i) |
|
|
1983 | \& { |
|
|
1984 | \& // set the relevant poll flags |
|
|
1985 | \& // could also call adns_processreadable etc. here |
|
|
1986 | \& struct pollfd *fd = fds + i; |
|
|
1987 | \& int revents = ev_clear_pending (iow + i); |
|
|
1988 | \& if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
|
|
1989 | \& if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
|
|
1990 | .Ve |
|
|
1991 | .PP |
|
|
1992 | .Vb 3 |
|
|
1993 | \& // now stop the watcher |
1636 | \& ev_io_stop (loop, iow + i); |
1994 | \& ev_io_stop (loop, iow + i); |
|
|
1995 | \& } |
1637 | .Ve |
1996 | .Ve |
1638 | .PP |
1997 | .PP |
1639 | .Vb 2 |
1998 | .Vb 2 |
1640 | \& adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
1999 | \& adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
|
|
2000 | \& } |
|
|
2001 | .Ve |
|
|
2002 | .PP |
|
|
2003 | Method 2: This would be just like method 1, but you run \f(CW\*(C`adns_afterpoll\*(C'\fR |
|
|
2004 | in the prepare watcher and would dispose of the check watcher. |
|
|
2005 | .PP |
|
|
2006 | Method 3: If the module to be embedded supports explicit event |
|
|
2007 | notification (adns does), you can also make use of the actual watcher |
|
|
2008 | callbacks, and only destroy/create the watchers in the prepare watcher. |
|
|
2009 | .PP |
|
|
2010 | .Vb 5 |
|
|
2011 | \& static void |
|
|
2012 | \& timer_cb (EV_P_ ev_timer *w, int revents) |
|
|
2013 | \& { |
|
|
2014 | \& adns_state ads = (adns_state)w->data; |
|
|
2015 | \& update_now (EV_A); |
|
|
2016 | .Ve |
|
|
2017 | .PP |
|
|
2018 | .Vb 2 |
|
|
2019 | \& adns_processtimeouts (ads, &tv_now); |
|
|
2020 | \& } |
|
|
2021 | .Ve |
|
|
2022 | .PP |
|
|
2023 | .Vb 5 |
|
|
2024 | \& static void |
|
|
2025 | \& io_cb (EV_P_ ev_io *w, int revents) |
|
|
2026 | \& { |
|
|
2027 | \& adns_state ads = (adns_state)w->data; |
|
|
2028 | \& update_now (EV_A); |
|
|
2029 | .Ve |
|
|
2030 | .PP |
|
|
2031 | .Vb 3 |
|
|
2032 | \& if (revents & EV_READ ) adns_processreadable (ads, w->fd, &tv_now); |
|
|
2033 | \& if (revents & EV_WRITE) adns_processwriteable (ads, w->fd, &tv_now); |
|
|
2034 | \& } |
|
|
2035 | .Ve |
|
|
2036 | .PP |
|
|
2037 | .Vb 1 |
|
|
2038 | \& // do not ever call adns_afterpoll |
|
|
2039 | .Ve |
|
|
2040 | .PP |
|
|
2041 | Method 4: Do not use a prepare or check watcher because the module you |
|
|
2042 | want to embed is too inflexible to support it. Instead, youc na override |
|
|
2043 | their poll function. The drawback with this solution is that the main |
|
|
2044 | loop is now no longer controllable by \s-1EV\s0. The \f(CW\*(C`Glib::EV\*(C'\fR module does |
|
|
2045 | this. |
|
|
2046 | .PP |
|
|
2047 | .Vb 4 |
|
|
2048 | \& static gint |
|
|
2049 | \& event_poll_func (GPollFD *fds, guint nfds, gint timeout) |
|
|
2050 | \& { |
|
|
2051 | \& int got_events = 0; |
|
|
2052 | .Ve |
|
|
2053 | .PP |
|
|
2054 | .Vb 2 |
|
|
2055 | \& for (n = 0; n < nfds; ++n) |
|
|
2056 | \& // create/start io watcher that sets the relevant bits in fds[n] and increment got_events |
|
|
2057 | .Ve |
|
|
2058 | .PP |
|
|
2059 | .Vb 2 |
|
|
2060 | \& if (timeout >= 0) |
|
|
2061 | \& // create/start timer |
|
|
2062 | .Ve |
|
|
2063 | .PP |
|
|
2064 | .Vb 2 |
|
|
2065 | \& // poll |
|
|
2066 | \& ev_loop (EV_A_ 0); |
|
|
2067 | .Ve |
|
|
2068 | .PP |
|
|
2069 | .Vb 3 |
|
|
2070 | \& // stop timer again |
|
|
2071 | \& if (timeout >= 0) |
|
|
2072 | \& ev_timer_stop (EV_A_ &to); |
|
|
2073 | .Ve |
|
|
2074 | .PP |
|
|
2075 | .Vb 3 |
|
|
2076 | \& // stop io watchers again - their callbacks should have set |
|
|
2077 | \& for (n = 0; n < nfds; ++n) |
|
|
2078 | \& ev_io_stop (EV_A_ iow [n]); |
|
|
2079 | .Ve |
|
|
2080 | .PP |
|
|
2081 | .Vb 2 |
|
|
2082 | \& return got_events; |
1641 | \& } |
2083 | \& } |
1642 | .Ve |
2084 | .Ve |
1643 | .ie n .Sh """ev_embed"" \- when one backend isn't enough..." |
2085 | .ie n .Sh """ev_embed"" \- when one backend isn't enough..." |
1644 | .el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..." |
2086 | .el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..." |
1645 | .IX Subsection "ev_embed - when one backend isn't enough..." |
2087 | .IX Subsection "ev_embed - when one backend isn't enough..." |
… | |
… | |
1714 | \& ev_embed_start (loop_hi, &embed); |
2156 | \& ev_embed_start (loop_hi, &embed); |
1715 | \& } |
2157 | \& } |
1716 | \& else |
2158 | \& else |
1717 | \& loop_lo = loop_hi; |
2159 | \& loop_lo = loop_hi; |
1718 | .Ve |
2160 | .Ve |
|
|
2161 | .PP |
|
|
2162 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
2163 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1719 | .IP "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
2164 | .IP "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
1720 | .IX Item "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" |
2165 | .IX Item "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" |
1721 | .PD 0 |
2166 | .PD 0 |
1722 | .IP "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
2167 | .IP "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
1723 | .IX Item "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" |
2168 | .IX Item "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" |
… | |
… | |
1730 | .IP "ev_embed_sweep (loop, ev_embed *)" 4 |
2175 | .IP "ev_embed_sweep (loop, ev_embed *)" 4 |
1731 | .IX Item "ev_embed_sweep (loop, ev_embed *)" |
2176 | .IX Item "ev_embed_sweep (loop, ev_embed *)" |
1732 | Make a single, non-blocking sweep over the embedded loop. This works |
2177 | Make a single, non-blocking sweep over the embedded loop. This works |
1733 | similarly to \f(CW\*(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\*(C'\fR, but in the most |
2178 | similarly to \f(CW\*(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\*(C'\fR, but in the most |
1734 | apropriate way for embedded loops. |
2179 | apropriate way for embedded loops. |
1735 | .IP "struct ev_loop *loop [read\-only]" 4 |
2180 | .IP "struct ev_loop *other [read\-only]" 4 |
1736 | .IX Item "struct ev_loop *loop [read-only]" |
2181 | .IX Item "struct ev_loop *other [read-only]" |
1737 | The embedded event loop. |
2182 | The embedded event loop. |
1738 | .ie n .Sh """ev_fork"" \- the audacity to resume the event loop after a fork" |
2183 | .ie n .Sh """ev_fork"" \- the audacity to resume the event loop after a fork" |
1739 | .el .Sh "\f(CWev_fork\fP \- 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" |
1740 | .IX Subsection "ev_fork - 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" |
1741 | Fork watchers are called when a \f(CW\*(C`fork ()\*(C'\fR was detected (usually because |
2186 | Fork watchers are called when a \f(CW\*(C`fork ()\*(C'\fR was detected (usually because |
… | |
… | |
1743 | \&\f(CW\*(C`ev_default_fork\*(C'\fR or \f(CW\*(C`ev_loop_fork\*(C'\fR). The invocation is done before the |
2188 | \&\f(CW\*(C`ev_default_fork\*(C'\fR or \f(CW\*(C`ev_loop_fork\*(C'\fR). The invocation is done before the |
1744 | event loop blocks next and before \f(CW\*(C`ev_check\*(C'\fR watchers are being called, |
2189 | event loop blocks next and before \f(CW\*(C`ev_check\*(C'\fR watchers are being called, |
1745 | and only in the child after the fork. If whoever good citizen calling |
2190 | and only in the child after the fork. If whoever good citizen calling |
1746 | \&\f(CW\*(C`ev_default_fork\*(C'\fR cheats and calls it in the wrong process, the fork |
2191 | \&\f(CW\*(C`ev_default_fork\*(C'\fR cheats and calls it in the wrong process, the fork |
1747 | handlers will be invoked, too, of course. |
2192 | handlers will be invoked, too, of course. |
|
|
2193 | .PP |
|
|
2194 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
2195 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1748 | .IP "ev_fork_init (ev_signal *, callback)" 4 |
2196 | .IP "ev_fork_init (ev_signal *, callback)" 4 |
1749 | .IX Item "ev_fork_init (ev_signal *, callback)" |
2197 | .IX Item "ev_fork_init (ev_signal *, callback)" |
1750 | Initialises and configures the fork watcher \- it has no parameters of any |
2198 | Initialises and configures the fork watcher \- it has no parameters of any |
1751 | kind. There is a \f(CW\*(C`ev_fork_set\*(C'\fR macro, but using it is utterly pointless, |
2199 | kind. There is a \f(CW\*(C`ev_fork_set\*(C'\fR macro, but using it is utterly pointless, |
1752 | believe me. |
2200 | believe me. |
… | |
… | |
1829 | .PP |
2277 | .PP |
1830 | .Vb 1 |
2278 | .Vb 1 |
1831 | \& #include <ev++.h> |
2279 | \& #include <ev++.h> |
1832 | .Ve |
2280 | .Ve |
1833 | .PP |
2281 | .PP |
1834 | (it is not installed by default). This automatically includes \fIev.h\fR |
2282 | This automatically includes \fIev.h\fR and puts all of its definitions (many |
1835 | and puts all of its definitions (many of them macros) into the global |
2283 | of them macros) into the global namespace. All \*(C+ specific things are |
1836 | namespace. All \*(C+ specific things are put into the \f(CW\*(C`ev\*(C'\fR namespace. |
2284 | put into the \f(CW\*(C`ev\*(C'\fR namespace. It should support all the same embedding |
|
|
2285 | options as \fIev.h\fR, most notably \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. |
1837 | .PP |
2286 | .PP |
1838 | It should support all the same embedding options as \fIev.h\fR, most notably |
2287 | Care has been taken to keep the overhead low. The only data member the \*(C+ |
1839 | \&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. |
2288 | classes add (compared to plain C\-style watchers) is the event loop pointer |
|
|
2289 | that the watcher is associated with (or no additional members at all if |
|
|
2290 | you disable \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR when embedding libev). |
|
|
2291 | .PP |
|
|
2292 | Currently, functions, and static and non-static member functions can be |
|
|
2293 | used as callbacks. Other types should be easy to add as long as they only |
|
|
2294 | need one additional pointer for context. If you need support for other |
|
|
2295 | types of functors please contact the author (preferably after implementing |
|
|
2296 | it). |
1840 | .PP |
2297 | .PP |
1841 | Here is a list of things available in the \f(CW\*(C`ev\*(C'\fR namespace: |
2298 | Here is a list of things available in the \f(CW\*(C`ev\*(C'\fR namespace: |
1842 | .ie n .IP """ev::READ""\fR, \f(CW""ev::WRITE"" etc." 4 |
2299 | .ie n .IP """ev::READ""\fR, \f(CW""ev::WRITE"" etc." 4 |
1843 | .el .IP "\f(CWev::READ\fR, \f(CWev::WRITE\fR etc." 4 |
2300 | .el .IP "\f(CWev::READ\fR, \f(CWev::WRITE\fR etc." 4 |
1844 | .IX Item "ev::READ, ev::WRITE etc." |
2301 | .IX Item "ev::READ, ev::WRITE etc." |
… | |
… | |
1856 | which is called \f(CW\*(C`ev::sig\*(C'\fR to avoid clashes with the \f(CW\*(C`signal\*(C'\fR macro |
2313 | which is called \f(CW\*(C`ev::sig\*(C'\fR to avoid clashes with the \f(CW\*(C`signal\*(C'\fR macro |
1857 | defines by many implementations. |
2314 | defines by many implementations. |
1858 | .Sp |
2315 | .Sp |
1859 | All of those classes have these methods: |
2316 | All of those classes have these methods: |
1860 | .RS 4 |
2317 | .RS 4 |
1861 | .IP "ev::TYPE::TYPE (object *, object::method *)" 4 |
2318 | .IP "ev::TYPE::TYPE ()" 4 |
1862 | .IX Item "ev::TYPE::TYPE (object *, object::method *)" |
2319 | .IX Item "ev::TYPE::TYPE ()" |
1863 | .PD 0 |
2320 | .PD 0 |
1864 | .IP "ev::TYPE::TYPE (object *, object::method *, struct ev_loop *)" 4 |
2321 | .IP "ev::TYPE::TYPE (struct ev_loop *)" 4 |
1865 | .IX Item "ev::TYPE::TYPE (object *, object::method *, struct ev_loop *)" |
2322 | .IX Item "ev::TYPE::TYPE (struct ev_loop *)" |
1866 | .IP "ev::TYPE::~TYPE" 4 |
2323 | .IP "ev::TYPE::~TYPE" 4 |
1867 | .IX Item "ev::TYPE::~TYPE" |
2324 | .IX Item "ev::TYPE::~TYPE" |
1868 | .PD |
2325 | .PD |
1869 | The constructor takes a pointer to an object and a method pointer to |
2326 | The constructor (optionally) takes an event loop to associate the watcher |
1870 | the event handler callback to call in this class. The constructor calls |
2327 | with. If it is omitted, it will use \f(CW\*(C`EV_DEFAULT\*(C'\fR. |
1871 | \&\f(CW\*(C`ev_init\*(C'\fR for you, which means you have to call the \f(CW\*(C`set\*(C'\fR method |
2328 | .Sp |
1872 | before starting it. If you do not specify a loop then the constructor |
2329 | The constructor calls \f(CW\*(C`ev_init\*(C'\fR for you, which means you have to call the |
1873 | automatically associates the default loop with this watcher. |
2330 | \&\f(CW\*(C`set\*(C'\fR method before starting it. |
|
|
2331 | .Sp |
|
|
2332 | It will not set a callback, however: You have to call the templated \f(CW\*(C`set\*(C'\fR |
|
|
2333 | method to set a callback before you can start the watcher. |
|
|
2334 | .Sp |
|
|
2335 | (The reason why you have to use a method is a limitation in \*(C+ which does |
|
|
2336 | not allow explicit template arguments for constructors). |
1874 | .Sp |
2337 | .Sp |
1875 | The destructor automatically stops the watcher if it is active. |
2338 | The destructor automatically stops the watcher if it is active. |
|
|
2339 | .IP "w\->set<class, &class::method> (object *)" 4 |
|
|
2340 | .IX Item "w->set<class, &class::method> (object *)" |
|
|
2341 | This method sets the callback method to call. The method has to have a |
|
|
2342 | signature of \f(CW\*(C`void (*)(ev_TYPE &, int)\*(C'\fR, it receives the watcher as |
|
|
2343 | first argument and the \f(CW\*(C`revents\*(C'\fR as second. The object must be given as |
|
|
2344 | parameter and is stored in the \f(CW\*(C`data\*(C'\fR member of the watcher. |
|
|
2345 | .Sp |
|
|
2346 | This method synthesizes efficient thunking code to call your method from |
|
|
2347 | the C callback that libev requires. If your compiler can inline your |
|
|
2348 | callback (i.e. it is visible to it at the place of the \f(CW\*(C`set\*(C'\fR call and |
|
|
2349 | your compiler is good :), then the method will be fully inlined into the |
|
|
2350 | thunking function, making it as fast as a direct C callback. |
|
|
2351 | .Sp |
|
|
2352 | Example: simple class declaration and watcher initialisation |
|
|
2353 | .Sp |
|
|
2354 | .Vb 4 |
|
|
2355 | \& struct myclass |
|
|
2356 | \& { |
|
|
2357 | \& void io_cb (ev::io &w, int revents) { } |
|
|
2358 | \& } |
|
|
2359 | .Ve |
|
|
2360 | .Sp |
|
|
2361 | .Vb 3 |
|
|
2362 | \& myclass obj; |
|
|
2363 | \& ev::io iow; |
|
|
2364 | \& iow.set <myclass, &myclass::io_cb> (&obj); |
|
|
2365 | .Ve |
|
|
2366 | .IP "w\->set<function> (void *data = 0)" 4 |
|
|
2367 | .IX Item "w->set<function> (void *data = 0)" |
|
|
2368 | Also sets a callback, but uses a static method or plain function as |
|
|
2369 | callback. The optional \f(CW\*(C`data\*(C'\fR argument will be stored in the watcher's |
|
|
2370 | \&\f(CW\*(C`data\*(C'\fR member and is free for you to use. |
|
|
2371 | .Sp |
|
|
2372 | The prototype of the \f(CW\*(C`function\*(C'\fR must be \f(CW\*(C`void (*)(ev::TYPE &w, int)\*(C'\fR. |
|
|
2373 | .Sp |
|
|
2374 | See the method\-\f(CW\*(C`set\*(C'\fR above for more details. |
|
|
2375 | .Sp |
|
|
2376 | Example: |
|
|
2377 | .Sp |
|
|
2378 | .Vb 2 |
|
|
2379 | \& static void io_cb (ev::io &w, int revents) { } |
|
|
2380 | \& iow.set <io_cb> (); |
|
|
2381 | .Ve |
1876 | .IP "w\->set (struct ev_loop *)" 4 |
2382 | .IP "w\->set (struct ev_loop *)" 4 |
1877 | .IX Item "w->set (struct ev_loop *)" |
2383 | .IX Item "w->set (struct ev_loop *)" |
1878 | Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only |
2384 | Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only |
1879 | do this when the watcher is inactive (and not pending either). |
2385 | do this when the watcher is inactive (and not pending either). |
1880 | .IP "w\->set ([args])" 4 |
2386 | .IP "w\->set ([args])" 4 |
1881 | .IX Item "w->set ([args])" |
2387 | .IX Item "w->set ([args])" |
1882 | Basically the same as \f(CW\*(C`ev_TYPE_set\*(C'\fR, with the same args. Must be |
2388 | Basically the same as \f(CW\*(C`ev_TYPE_set\*(C'\fR, with the same args. Must be |
1883 | called at least once. Unlike the C counterpart, an active watcher gets |
2389 | called at least once. Unlike the C counterpart, an active watcher gets |
1884 | automatically stopped and restarted. |
2390 | automatically stopped and restarted when reconfiguring it with this |
|
|
2391 | method. |
1885 | .IP "w\->start ()" 4 |
2392 | .IP "w\->start ()" 4 |
1886 | .IX Item "w->start ()" |
2393 | .IX Item "w->start ()" |
1887 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument as the |
2394 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument, as the |
1888 | constructor already takes the loop. |
2395 | constructor already stores the event loop. |
1889 | .IP "w\->stop ()" 4 |
2396 | .IP "w\->stop ()" 4 |
1890 | .IX Item "w->stop ()" |
2397 | .IX Item "w->stop ()" |
1891 | Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument. |
2398 | Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument. |
1892 | .ie n .IP "w\->again () ""ev::timer""\fR, \f(CW""ev::periodic"" only" 4 |
2399 | .ie n .IP "w\->again () (""ev::timer""\fR, \f(CW""ev::periodic"" only)" 4 |
1893 | .el .IP "w\->again () \f(CWev::timer\fR, \f(CWev::periodic\fR only" 4 |
2400 | .el .IP "w\->again () (\f(CWev::timer\fR, \f(CWev::periodic\fR only)" 4 |
1894 | .IX Item "w->again () ev::timer, ev::periodic only" |
2401 | .IX Item "w->again () (ev::timer, ev::periodic only)" |
1895 | For \f(CW\*(C`ev::timer\*(C'\fR and \f(CW\*(C`ev::periodic\*(C'\fR, this invokes the corresponding |
2402 | For \f(CW\*(C`ev::timer\*(C'\fR and \f(CW\*(C`ev::periodic\*(C'\fR, this invokes the corresponding |
1896 | \&\f(CW\*(C`ev_TYPE_again\*(C'\fR function. |
2403 | \&\f(CW\*(C`ev_TYPE_again\*(C'\fR function. |
1897 | .ie n .IP "w\->sweep () ""ev::embed"" only" 4 |
2404 | .ie n .IP "w\->sweep () (""ev::embed"" only)" 4 |
1898 | .el .IP "w\->sweep () \f(CWev::embed\fR only" 4 |
2405 | .el .IP "w\->sweep () (\f(CWev::embed\fR only)" 4 |
1899 | .IX Item "w->sweep () ev::embed only" |
2406 | .IX Item "w->sweep () (ev::embed only)" |
1900 | Invokes \f(CW\*(C`ev_embed_sweep\*(C'\fR. |
2407 | Invokes \f(CW\*(C`ev_embed_sweep\*(C'\fR. |
1901 | .ie n .IP "w\->update () ""ev::stat"" only" 4 |
2408 | .ie n .IP "w\->update () (""ev::stat"" only)" 4 |
1902 | .el .IP "w\->update () \f(CWev::stat\fR only" 4 |
2409 | .el .IP "w\->update () (\f(CWev::stat\fR only)" 4 |
1903 | .IX Item "w->update () ev::stat only" |
2410 | .IX Item "w->update () (ev::stat only)" |
1904 | Invokes \f(CW\*(C`ev_stat_stat\*(C'\fR. |
2411 | Invokes \f(CW\*(C`ev_stat_stat\*(C'\fR. |
1905 | .RE |
2412 | .RE |
1906 | .RS 4 |
2413 | .RS 4 |
1907 | .RE |
2414 | .RE |
1908 | .PP |
2415 | .PP |
… | |
… | |
1919 | .Vb 2 |
2426 | .Vb 2 |
1920 | \& myclass (); |
2427 | \& myclass (); |
1921 | \& } |
2428 | \& } |
1922 | .Ve |
2429 | .Ve |
1923 | .PP |
2430 | .PP |
1924 | .Vb 6 |
2431 | .Vb 4 |
1925 | \& myclass::myclass (int fd) |
2432 | \& myclass::myclass (int fd) |
1926 | \& : io (this, &myclass::io_cb), |
|
|
1927 | \& idle (this, &myclass::idle_cb) |
|
|
1928 | \& { |
2433 | \& { |
|
|
2434 | \& io .set <myclass, &myclass::io_cb > (this); |
|
|
2435 | \& idle.set <myclass, &myclass::idle_cb> (this); |
|
|
2436 | .Ve |
|
|
2437 | .PP |
|
|
2438 | .Vb 2 |
1929 | \& io.start (fd, ev::READ); |
2439 | \& io.start (fd, ev::READ); |
1930 | \& } |
2440 | \& } |
1931 | .Ve |
2441 | .Ve |
1932 | .SH "MACRO MAGIC" |
2442 | .SH "MACRO MAGIC" |
1933 | .IX Header "MACRO MAGIC" |
2443 | .IX Header "MACRO MAGIC" |
1934 | Libev can be compiled with a variety of options, the most fundemantal is |
2444 | Libev can be compiled with a variety of options, the most fundamantal |
1935 | \&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines wether (most) functions and |
2445 | of which is \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines whether (most) |
1936 | callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument. |
2446 | functions and callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument. |
1937 | .PP |
2447 | .PP |
1938 | To make it easier to write programs that cope with either variant, the |
2448 | To make it easier to write programs that cope with either variant, the |
1939 | following macros are defined: |
2449 | following macros are defined: |
1940 | .ie n .IP """EV_A""\fR, \f(CW""EV_A_""" 4 |
2450 | .ie n .IP """EV_A""\fR, \f(CW""EV_A_""" 4 |
1941 | .el .IP "\f(CWEV_A\fR, \f(CWEV_A_\fR" 4 |
2451 | .el .IP "\f(CWEV_A\fR, \f(CWEV_A_\fR" 4 |
… | |
… | |
1975 | .el .IP "\f(CWEV_DEFAULT\fR, \f(CWEV_DEFAULT_\fR" 4 |
2485 | .el .IP "\f(CWEV_DEFAULT\fR, \f(CWEV_DEFAULT_\fR" 4 |
1976 | .IX Item "EV_DEFAULT, EV_DEFAULT_" |
2486 | .IX Item "EV_DEFAULT, EV_DEFAULT_" |
1977 | Similar to the other two macros, this gives you the value of the default |
2487 | Similar to the other two macros, this gives you the value of the default |
1978 | loop, if multiple loops are supported (\*(L"ev loop default\*(R"). |
2488 | loop, if multiple loops are supported (\*(L"ev loop default\*(R"). |
1979 | .PP |
2489 | .PP |
1980 | Example: Declare and initialise a check watcher, working regardless of |
2490 | Example: Declare and initialise a check watcher, utilising the above |
1981 | wether multiple loops are supported or not. |
2491 | macros so it will work regardless of whether multiple loops are supported |
|
|
2492 | or not. |
1982 | .PP |
2493 | .PP |
1983 | .Vb 5 |
2494 | .Vb 5 |
1984 | \& static void |
2495 | \& static void |
1985 | \& check_cb (EV_P_ ev_timer *w, int revents) |
2496 | \& check_cb (EV_P_ ev_timer *w, int revents) |
1986 | \& { |
2497 | \& { |
… | |
… | |
1999 | Libev can (and often is) directly embedded into host |
2510 | Libev can (and often is) directly embedded into host |
2000 | applications. Examples of applications that embed it include the Deliantra |
2511 | applications. Examples of applications that embed it include the Deliantra |
2001 | Game Server, the \s-1EV\s0 perl module, the \s-1GNU\s0 Virtual Private Ethernet (gvpe) |
2512 | Game Server, the \s-1EV\s0 perl module, the \s-1GNU\s0 Virtual Private Ethernet (gvpe) |
2002 | and rxvt\-unicode. |
2513 | and rxvt\-unicode. |
2003 | .PP |
2514 | .PP |
2004 | The goal is to enable you to just copy the neecssary files into your |
2515 | The goal is to enable you to just copy the necessary files into your |
2005 | source directory without having to change even a single line in them, so |
2516 | source directory without having to change even a single line in them, so |
2006 | you can easily upgrade by simply copying (or having a checked-out copy of |
2517 | you can easily upgrade by simply copying (or having a checked-out copy of |
2007 | libev somewhere in your source tree). |
2518 | libev somewhere in your source tree). |
2008 | .Sh "\s-1FILESETS\s0" |
2519 | .Sh "\s-1FILESETS\s0" |
2009 | .IX Subsection "FILESETS" |
2520 | .IX Subsection "FILESETS" |
… | |
… | |
2049 | .Vb 1 |
2560 | .Vb 1 |
2050 | \& ev_win32.c required on win32 platforms only |
2561 | \& ev_win32.c required on win32 platforms only |
2051 | .Ve |
2562 | .Ve |
2052 | .PP |
2563 | .PP |
2053 | .Vb 5 |
2564 | .Vb 5 |
2054 | \& ev_select.c only when select backend is enabled (which is by default) |
2565 | \& ev_select.c only when select backend is enabled (which is enabled by default) |
2055 | \& ev_poll.c only when poll backend is enabled (disabled by default) |
2566 | \& ev_poll.c only when poll backend is enabled (disabled by default) |
2056 | \& ev_epoll.c only when the epoll backend is enabled (disabled by default) |
2567 | \& ev_epoll.c only when the epoll backend is enabled (disabled by default) |
2057 | \& ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
2568 | \& ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
2058 | \& ev_port.c only when the solaris port backend is enabled (disabled by default) |
2569 | \& ev_port.c only when the solaris port backend is enabled (disabled by default) |
2059 | .Ve |
2570 | .Ve |
… | |
… | |
2114 | .IX Item "EV_USE_MONOTONIC" |
2625 | .IX Item "EV_USE_MONOTONIC" |
2115 | If defined to be \f(CW1\fR, libev will try to detect the availability of the |
2626 | If defined to be \f(CW1\fR, libev will try to detect the availability of the |
2116 | monotonic clock option at both compiletime and runtime. Otherwise no use |
2627 | monotonic clock option at both compiletime and runtime. Otherwise no use |
2117 | of the monotonic clock option will be attempted. If you enable this, you |
2628 | of the monotonic clock option will be attempted. If you enable this, you |
2118 | usually have to link against librt or something similar. Enabling it when |
2629 | usually have to link against librt or something similar. Enabling it when |
2119 | the functionality isn't available is safe, though, althoguh you have |
2630 | the functionality isn't available is safe, though, although you have |
2120 | to make sure you link against any libraries where the \f(CW\*(C`clock_gettime\*(C'\fR |
2631 | to make sure you link against any libraries where the \f(CW\*(C`clock_gettime\*(C'\fR |
2121 | function is hiding in (often \fI\-lrt\fR). |
2632 | function is hiding in (often \fI\-lrt\fR). |
2122 | .IP "\s-1EV_USE_REALTIME\s0" 4 |
2633 | .IP "\s-1EV_USE_REALTIME\s0" 4 |
2123 | .IX Item "EV_USE_REALTIME" |
2634 | .IX Item "EV_USE_REALTIME" |
2124 | If defined to be \f(CW1\fR, libev will try to detect the availability of the |
2635 | If defined to be \f(CW1\fR, libev will try to detect the availability of the |
2125 | realtime clock option at compiletime (and assume its availability at |
2636 | realtime clock option at compiletime (and assume its availability at |
2126 | runtime if successful). Otherwise no use of the realtime clock option will |
2637 | runtime if successful). Otherwise no use of the realtime clock option will |
2127 | be attempted. This effectively replaces \f(CW\*(C`gettimeofday\*(C'\fR by \f(CW\*(C`clock_get |
2638 | be attempted. This effectively replaces \f(CW\*(C`gettimeofday\*(C'\fR by \f(CW\*(C`clock_get |
2128 | (CLOCK_REALTIME, ...)\*(C'\fR and will not normally affect correctness. See tzhe note about libraries |
2639 | (CLOCK_REALTIME, ...)\*(C'\fR and will not normally affect correctness. See the |
2129 | in the description of \f(CW\*(C`EV_USE_MONOTONIC\*(C'\fR, though. |
2640 | note about libraries in the description of \f(CW\*(C`EV_USE_MONOTONIC\*(C'\fR, though. |
|
|
2641 | .IP "\s-1EV_USE_NANOSLEEP\s0" 4 |
|
|
2642 | .IX Item "EV_USE_NANOSLEEP" |
|
|
2643 | If defined to be \f(CW1\fR, libev will assume that \f(CW\*(C`nanosleep ()\*(C'\fR is available |
|
|
2644 | and will use it for delays. Otherwise it will use \f(CW\*(C`select ()\*(C'\fR. |
2130 | .IP "\s-1EV_USE_SELECT\s0" 4 |
2645 | .IP "\s-1EV_USE_SELECT\s0" 4 |
2131 | .IX Item "EV_USE_SELECT" |
2646 | .IX Item "EV_USE_SELECT" |
2132 | If undefined or defined to be \f(CW1\fR, libev will compile in support for the |
2647 | If undefined or defined to be \f(CW1\fR, libev will compile in support for the |
2133 | \&\f(CW\*(C`select\*(C'\fR(2) backend. No attempt at autodetection will be done: if no |
2648 | \&\f(CW\*(C`select\*(C'\fR(2) backend. No attempt at autodetection will be done: if no |
2134 | other method takes over, select will be it. Otherwise the select backend |
2649 | other method takes over, select will be it. Otherwise the select backend |
… | |
… | |
2188 | interface to speed up \f(CW\*(C`ev_stat\*(C'\fR watchers. Its actual availability will |
2703 | interface to speed up \f(CW\*(C`ev_stat\*(C'\fR watchers. Its actual availability will |
2189 | be detected at runtime. |
2704 | be detected at runtime. |
2190 | .IP "\s-1EV_H\s0" 4 |
2705 | .IP "\s-1EV_H\s0" 4 |
2191 | .IX Item "EV_H" |
2706 | .IX Item "EV_H" |
2192 | The name of the \fIev.h\fR header file used to include it. The default if |
2707 | The name of the \fIev.h\fR header file used to include it. The default if |
2193 | undefined is \f(CW\*(C`<ev.h>\*(C'\fR in \fIevent.h\fR and \f(CW"ev.h"\fR in \fIev.c\fR. This |
2708 | undefined is \f(CW"ev.h"\fR in \fIevent.h\fR and \fIev.c\fR. This can be used to |
2194 | can be used to virtually rename the \fIev.h\fR header file in case of conflicts. |
2709 | virtually rename the \fIev.h\fR header file in case of conflicts. |
2195 | .IP "\s-1EV_CONFIG_H\s0" 4 |
2710 | .IP "\s-1EV_CONFIG_H\s0" 4 |
2196 | .IX Item "EV_CONFIG_H" |
2711 | .IX Item "EV_CONFIG_H" |
2197 | If \f(CW\*(C`EV_STANDALONE\*(C'\fR isn't \f(CW1\fR, this variable can be used to override |
2712 | If \f(CW\*(C`EV_STANDALONE\*(C'\fR isn't \f(CW1\fR, this variable can be used to override |
2198 | \&\fIev.c\fR's idea of where to find the \fIconfig.h\fR file, similarly to |
2713 | \&\fIev.c\fR's idea of where to find the \fIconfig.h\fR file, similarly to |
2199 | \&\f(CW\*(C`EV_H\*(C'\fR, above. |
2714 | \&\f(CW\*(C`EV_H\*(C'\fR, above. |
2200 | .IP "\s-1EV_EVENT_H\s0" 4 |
2715 | .IP "\s-1EV_EVENT_H\s0" 4 |
2201 | .IX Item "EV_EVENT_H" |
2716 | .IX Item "EV_EVENT_H" |
2202 | Similarly to \f(CW\*(C`EV_H\*(C'\fR, this macro can be used to override \fIevent.c\fR's idea |
2717 | Similarly to \f(CW\*(C`EV_H\*(C'\fR, this macro can be used to override \fIevent.c\fR's idea |
2203 | of how the \fIevent.h\fR header can be found. |
2718 | of how the \fIevent.h\fR header can be found, the dfeault is \f(CW"event.h"\fR. |
2204 | .IP "\s-1EV_PROTOTYPES\s0" 4 |
2719 | .IP "\s-1EV_PROTOTYPES\s0" 4 |
2205 | .IX Item "EV_PROTOTYPES" |
2720 | .IX Item "EV_PROTOTYPES" |
2206 | If defined to be \f(CW0\fR, then \fIev.h\fR will not define any function |
2721 | If defined to be \f(CW0\fR, then \fIev.h\fR will not define any function |
2207 | prototypes, but still define all the structs and other symbols. This is |
2722 | prototypes, but still define all the structs and other symbols. This is |
2208 | occasionally useful if you want to provide your own wrapper functions |
2723 | occasionally useful if you want to provide your own wrapper functions |
… | |
… | |
2212 | If undefined or defined to \f(CW1\fR, then all event-loop-specific functions |
2727 | If undefined or defined to \f(CW1\fR, then all event-loop-specific functions |
2213 | will have the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument, and you can create |
2728 | will have the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument, and you can create |
2214 | additional independent event loops. Otherwise there will be no support |
2729 | additional independent event loops. Otherwise there will be no support |
2215 | for multiple event loops and there is no first event loop pointer |
2730 | for multiple event loops and there is no first event loop pointer |
2216 | argument. Instead, all functions act on the single default loop. |
2731 | argument. Instead, all functions act on the single default loop. |
|
|
2732 | .IP "\s-1EV_MINPRI\s0" 4 |
|
|
2733 | .IX Item "EV_MINPRI" |
|
|
2734 | .PD 0 |
|
|
2735 | .IP "\s-1EV_MAXPRI\s0" 4 |
|
|
2736 | .IX Item "EV_MAXPRI" |
|
|
2737 | .PD |
|
|
2738 | The range of allowed priorities. \f(CW\*(C`EV_MINPRI\*(C'\fR must be smaller or equal to |
|
|
2739 | \&\f(CW\*(C`EV_MAXPRI\*(C'\fR, but otherwise there are no non-obvious limitations. You can |
|
|
2740 | provide for more priorities by overriding those symbols (usually defined |
|
|
2741 | to be \f(CW\*(C`\-2\*(C'\fR and \f(CW2\fR, respectively). |
|
|
2742 | .Sp |
|
|
2743 | When doing priority-based operations, libev usually has to linearly search |
|
|
2744 | all the priorities, so having many of them (hundreds) uses a lot of space |
|
|
2745 | and time, so using the defaults of five priorities (\-2 .. +2) is usually |
|
|
2746 | fine. |
|
|
2747 | .Sp |
|
|
2748 | If your embedding app does not need any priorities, defining these both to |
|
|
2749 | \&\f(CW0\fR will save some memory and cpu. |
2217 | .IP "\s-1EV_PERIODIC_ENABLE\s0" 4 |
2750 | .IP "\s-1EV_PERIODIC_ENABLE\s0" 4 |
2218 | .IX Item "EV_PERIODIC_ENABLE" |
2751 | .IX Item "EV_PERIODIC_ENABLE" |
2219 | If undefined or defined to be \f(CW1\fR, then periodic timers are supported. If |
2752 | If undefined or defined to be \f(CW1\fR, then periodic timers are supported. If |
|
|
2753 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
|
|
2754 | code. |
|
|
2755 | .IP "\s-1EV_IDLE_ENABLE\s0" 4 |
|
|
2756 | .IX Item "EV_IDLE_ENABLE" |
|
|
2757 | If undefined or defined to be \f(CW1\fR, then idle watchers are supported. If |
2220 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
2758 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
2221 | code. |
2759 | code. |
2222 | .IP "\s-1EV_EMBED_ENABLE\s0" 4 |
2760 | .IP "\s-1EV_EMBED_ENABLE\s0" 4 |
2223 | .IX Item "EV_EMBED_ENABLE" |
2761 | .IX Item "EV_EMBED_ENABLE" |
2224 | If undefined or defined to be \f(CW1\fR, then embed watchers are supported. If |
2762 | If undefined or defined to be \f(CW1\fR, then embed watchers are supported. If |
… | |
… | |
2242 | pid. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), usually more |
2780 | pid. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), usually more |
2243 | than enough. If you need to manage thousands of children you might want to |
2781 | than enough. If you need to manage thousands of children you might want to |
2244 | increase this value (\fImust\fR be a power of two). |
2782 | increase this value (\fImust\fR be a power of two). |
2245 | .IP "\s-1EV_INOTIFY_HASHSIZE\s0" 4 |
2783 | .IP "\s-1EV_INOTIFY_HASHSIZE\s0" 4 |
2246 | .IX Item "EV_INOTIFY_HASHSIZE" |
2784 | .IX Item "EV_INOTIFY_HASHSIZE" |
2247 | \&\f(CW\*(C`ev_staz\*(C'\fR watchers use a small hash table to distribute workload by |
2785 | \&\f(CW\*(C`ev_stat\*(C'\fR watchers use a small hash table to distribute workload by |
2248 | inotify watch id. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), |
2786 | inotify watch id. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), |
2249 | usually more than enough. If you need to manage thousands of \f(CW\*(C`ev_stat\*(C'\fR |
2787 | usually more than enough. If you need to manage thousands of \f(CW\*(C`ev_stat\*(C'\fR |
2250 | watchers you might want to increase this value (\fImust\fR be a power of |
2788 | watchers you might want to increase this value (\fImust\fR be a power of |
2251 | two). |
2789 | two). |
2252 | .IP "\s-1EV_COMMON\s0" 4 |
2790 | .IP "\s-1EV_COMMON\s0" 4 |
… | |
… | |
2271 | .IP "ev_set_cb (ev, cb)" 4 |
2809 | .IP "ev_set_cb (ev, cb)" 4 |
2272 | .IX Item "ev_set_cb (ev, cb)" |
2810 | .IX Item "ev_set_cb (ev, cb)" |
2273 | .PD |
2811 | .PD |
2274 | Can be used to change the callback member declaration in each watcher, |
2812 | Can be used to change the callback member declaration in each watcher, |
2275 | and the way callbacks are invoked and set. Must expand to a struct member |
2813 | and the way callbacks are invoked and set. Must expand to a struct member |
2276 | definition and a statement, respectively. See the \fIev.v\fR header file for |
2814 | definition and a statement, respectively. See the \fIev.h\fR header file for |
2277 | their default definitions. One possible use for overriding these is to |
2815 | their default definitions. One possible use for overriding these is to |
2278 | avoid the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument in all cases, or to use |
2816 | avoid the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument in all cases, or to use |
2279 | method calls instead of plain function calls in \*(C+. |
2817 | method calls instead of plain function calls in \*(C+. |
|
|
2818 | .Sh "\s-1EXPORTED\s0 \s-1API\s0 \s-1SYMBOLS\s0" |
|
|
2819 | .IX Subsection "EXPORTED API SYMBOLS" |
|
|
2820 | If you need to re-export the \s-1API\s0 (e.g. via a dll) and you need a list of |
|
|
2821 | exported symbols, you can use the provided \fISymbol.*\fR files which list |
|
|
2822 | all public symbols, one per line: |
|
|
2823 | .Sp |
|
|
2824 | .Vb 2 |
|
|
2825 | \& Symbols.ev for libev proper |
|
|
2826 | \& Symbols.event for the libevent emulation |
|
|
2827 | .Ve |
|
|
2828 | .Sp |
|
|
2829 | This can also be used to rename all public symbols to avoid clashes with |
|
|
2830 | multiple versions of libev linked together (which is obviously bad in |
|
|
2831 | itself, but sometimes it is inconvinient to avoid this). |
|
|
2832 | .Sp |
|
|
2833 | A sed command like this will create wrapper \f(CW\*(C`#define\*(C'\fR's that you need to |
|
|
2834 | include before including \fIev.h\fR: |
|
|
2835 | .Sp |
|
|
2836 | .Vb 1 |
|
|
2837 | \& <Symbols.ev sed -e "s/.*/#define & myprefix_&/" >wrap.h |
|
|
2838 | .Ve |
|
|
2839 | .Sp |
|
|
2840 | This would create a file \fIwrap.h\fR which essentially looks like this: |
|
|
2841 | .Sp |
|
|
2842 | .Vb 4 |
|
|
2843 | \& #define ev_backend myprefix_ev_backend |
|
|
2844 | \& #define ev_check_start myprefix_ev_check_start |
|
|
2845 | \& #define ev_check_stop myprefix_ev_check_stop |
|
|
2846 | \& ... |
|
|
2847 | .Ve |
2280 | .Sh "\s-1EXAMPLES\s0" |
2848 | .Sh "\s-1EXAMPLES\s0" |
2281 | .IX Subsection "EXAMPLES" |
2849 | .IX Subsection "EXAMPLES" |
2282 | For a real-world example of a program the includes libev |
2850 | For a real-world example of a program the includes libev |
2283 | verbatim, you can have a look at the \s-1EV\s0 perl module |
2851 | verbatim, you can have a look at the \s-1EV\s0 perl module |
2284 | (<http://software.schmorp.de/pkg/EV.html>). It has the libev files in |
2852 | (<http://software.schmorp.de/pkg/EV.html>). It has the libev files in |
… | |
… | |
2286 | interface) and \fI\s-1EV\s0.xs\fR (implementation) files. Only the \fI\s-1EV\s0.xs\fR file |
2854 | interface) and \fI\s-1EV\s0.xs\fR (implementation) files. Only the \fI\s-1EV\s0.xs\fR file |
2287 | will be compiled. It is pretty complex because it provides its own header |
2855 | will be compiled. It is pretty complex because it provides its own header |
2288 | file. |
2856 | file. |
2289 | .Sp |
2857 | .Sp |
2290 | The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file |
2858 | The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file |
2291 | that everybody includes and which overrides some autoconf choices: |
2859 | that everybody includes and which overrides some configure choices: |
2292 | .Sp |
2860 | .Sp |
2293 | .Vb 4 |
2861 | .Vb 9 |
|
|
2862 | \& #define EV_MINIMAL 1 |
2294 | \& #define EV_USE_POLL 0 |
2863 | \& #define EV_USE_POLL 0 |
2295 | \& #define EV_MULTIPLICITY 0 |
2864 | \& #define EV_MULTIPLICITY 0 |
2296 | \& #define EV_PERIODICS 0 |
2865 | \& #define EV_PERIODIC_ENABLE 0 |
|
|
2866 | \& #define EV_STAT_ENABLE 0 |
|
|
2867 | \& #define EV_FORK_ENABLE 0 |
2297 | \& #define EV_CONFIG_H <config.h> |
2868 | \& #define EV_CONFIG_H <config.h> |
|
|
2869 | \& #define EV_MINPRI 0 |
|
|
2870 | \& #define EV_MAXPRI 0 |
2298 | .Ve |
2871 | .Ve |
2299 | .Sp |
2872 | .Sp |
2300 | .Vb 1 |
2873 | .Vb 1 |
2301 | \& #include "ev++.h" |
2874 | \& #include "ev++.h" |
2302 | .Ve |
2875 | .Ve |
… | |
… | |
2310 | .SH "COMPLEXITIES" |
2883 | .SH "COMPLEXITIES" |
2311 | .IX Header "COMPLEXITIES" |
2884 | .IX Header "COMPLEXITIES" |
2312 | In this section the complexities of (many of) the algorithms used inside |
2885 | In this section the complexities of (many of) the algorithms used inside |
2313 | libev will be explained. For complexity discussions about backends see the |
2886 | libev will be explained. For complexity discussions about backends see the |
2314 | documentation for \f(CW\*(C`ev_default_init\*(C'\fR. |
2887 | documentation for \f(CW\*(C`ev_default_init\*(C'\fR. |
|
|
2888 | .Sp |
|
|
2889 | All of the following are about amortised time: If an array needs to be |
|
|
2890 | extended, libev needs to realloc and move the whole array, but this |
|
|
2891 | happens asymptotically never with higher number of elements, so O(1) might |
|
|
2892 | mean it might do a lengthy realloc operation in rare cases, but on average |
|
|
2893 | it is much faster and asymptotically approaches constant time. |
2315 | .RS 4 |
2894 | .RS 4 |
2316 | .IP "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" 4 |
2895 | .IP "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" 4 |
2317 | .IX Item "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" |
2896 | .IX Item "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" |
2318 | .PD 0 |
2897 | This means that, when you have a watcher that triggers in one hour and |
|
|
2898 | there are 100 watchers that would trigger before that then inserting will |
|
|
2899 | have to skip roughly seven (\f(CW\*(C`ld 100\*(C'\fR) of these watchers. |
2319 | .IP "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" 4 |
2900 | .IP "Changing timer/periodic watchers (by autorepeat or calling again): O(log skipped_other_timers)" 4 |
2320 | .IX Item "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" |
2901 | .IX Item "Changing timer/periodic watchers (by autorepeat or calling again): O(log skipped_other_timers)" |
|
|
2902 | That means that changing a timer costs less than removing/adding them |
|
|
2903 | as only the relative motion in the event queue has to be paid for. |
2321 | .IP "Starting io/check/prepare/idle/signal/child watchers: O(1)" 4 |
2904 | .IP "Starting io/check/prepare/idle/signal/child watchers: O(1)" 4 |
2322 | .IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)" |
2905 | .IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)" |
|
|
2906 | These just add the watcher into an array or at the head of a list. |
2323 | .IP "Stopping check/prepare/idle watchers: O(1)" 4 |
2907 | .IP "Stopping check/prepare/idle watchers: O(1)" 4 |
2324 | .IX Item "Stopping check/prepare/idle watchers: O(1)" |
2908 | .IX Item "Stopping check/prepare/idle watchers: O(1)" |
|
|
2909 | .PD 0 |
2325 | .IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % \s-1EV_PID_HASHSIZE\s0))" 4 |
2910 | .IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % \s-1EV_PID_HASHSIZE\s0))" 4 |
2326 | .IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))" |
2911 | .IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))" |
|
|
2912 | .PD |
|
|
2913 | These watchers are stored in lists then need to be walked to find the |
|
|
2914 | correct watcher to remove. The lists are usually short (you don't usually |
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|
2915 | have many watchers waiting for the same fd or signal). |
2327 | .IP "Finding the next timer per loop iteration: O(1)" 4 |
2916 | .IP "Finding the next timer in each loop iteration: O(1)" 4 |
2328 | .IX Item "Finding the next timer per loop iteration: O(1)" |
2917 | .IX Item "Finding the next timer in each loop iteration: O(1)" |
|
|
2918 | By virtue of using a binary heap, the next timer is always found at the |
|
|
2919 | beginning of the storage array. |
2329 | .IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4 |
2920 | .IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4 |
2330 | .IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" |
2921 | .IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" |
2331 | .IP "Activating one watcher: O(1)" 4 |
2922 | A change means an I/O watcher gets started or stopped, which requires |
2332 | .IX Item "Activating one watcher: O(1)" |
2923 | libev to recalculate its status (and possibly tell the kernel, depending |
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|
2924 | on backend and wether \f(CW\*(C`ev_io_set\*(C'\fR was used). |
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|
2925 | .IP "Activating one watcher (putting it into the pending state): O(1)" 4 |
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2926 | .IX Item "Activating one watcher (putting it into the pending state): O(1)" |
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|
2927 | .PD 0 |
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|
2928 | .IP "Priority handling: O(number_of_priorities)" 4 |
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|
2929 | .IX Item "Priority handling: O(number_of_priorities)" |
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|
2930 | .PD |
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|
2931 | Priorities are implemented by allocating some space for each |
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|
2932 | priority. When doing priority-based operations, libev usually has to |
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2933 | linearly search all the priorities, but starting/stopping and activating |
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2934 | watchers becomes O(1) w.r.t. prioritiy handling. |
2333 | .RE |
2935 | .RE |
2334 | .RS 4 |
2936 | .RS 4 |
2335 | .PD |
|
|
2336 | .SH "AUTHOR" |
2937 | .SH "AUTHOR" |
2337 | .IX Header "AUTHOR" |
2938 | .IX Header "AUTHOR" |
2338 | Marc Lehmann <libev@schmorp.de>. |
2939 | Marc Lehmann <libev@schmorp.de>. |