… | |
… | |
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 "2007-12-07" "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 |
… | |
… | |
201 | The newest version of this document is also available as a html-formatted |
201 | The newest version of this document is also available as a html-formatted |
202 | web page you might find easier to navigate when reading it for the first |
202 | web page you might find easier to navigate when reading it for the first |
203 | time: <http://cvs.schmorp.de/libev/ev.html>. |
203 | time: <http://cvs.schmorp.de/libev/ev.html>. |
204 | .PP |
204 | .PP |
205 | 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 |
206 | 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 |
207 | these event sources and provide your program with events. |
207 | these event sources and provide your program with events. |
208 | .PP |
208 | .PP |
209 | 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 |
210 | (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 |
211 | communicate events via a callback mechanism. |
211 | communicate events via a callback mechanism. |
212 | .PP |
212 | .PP |
213 | You register interest in certain events by registering so-called \fIevent |
213 | You register interest in certain events by registering so-called \fIevent |
214 | 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 |
215 | 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 |
216 | watcher. |
216 | watcher. |
217 | .SH "FEATURES" |
217 | .Sh "\s-1FEATURES\s0" |
218 | .IX Header "FEATURES" |
218 | .IX Subsection "FEATURES" |
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 |
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 |
220 | 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 |
221 | 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 |
222 | (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 |
223 | 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 |
… | |
… | |
228 | (\f(CW\*(C`ev_fork\*(C'\fR). |
228 | (\f(CW\*(C`ev_fork\*(C'\fR). |
229 | .PP |
229 | .PP |
230 | It also is quite fast (see this |
230 | It also is quite fast (see this |
231 | benchmark comparing it to libevent |
231 | benchmark comparing it to libevent |
232 | for example). |
232 | for example). |
233 | .SH "CONVENTIONS" |
233 | .Sh "\s-1CONVENTIONS\s0" |
234 | .IX Header "CONVENTIONS" |
234 | .IX Subsection "CONVENTIONS" |
235 | Libev is very configurable. In this manual the default configuration will |
235 | Libev is very configurable. In this manual the default configuration will |
236 | be described, which supports multiple event loops. For more info about |
236 | be described, which supports multiple event loops. For more info about |
237 | 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 |
238 | this manual. If libev was configured without support for multiple event |
238 | this manual. If libev was configured without support for multiple event |
239 | 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 |
240 | (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. |
241 | .SH "TIME REPRESENTATION" |
241 | .Sh "\s-1TIME\s0 \s-1REPRESENTATION\s0" |
242 | .IX Header "TIME REPRESENTATION" |
242 | .IX Subsection "TIME REPRESENTATION" |
243 | Libev represents time as a single floating point number, representing the |
243 | Libev represents time as a single floating point number, representing the |
244 | (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 |
245 | 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 |
246 | 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 |
247 | 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 |
248 | 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. |
249 | .SH "GLOBAL FUNCTIONS" |
251 | .SH "GLOBAL FUNCTIONS" |
250 | .IX Header "GLOBAL FUNCTIONS" |
252 | .IX Header "GLOBAL FUNCTIONS" |
251 | These functions can be called anytime, even before initialising the |
253 | These functions can be called anytime, even before initialising the |
252 | library in any way. |
254 | library in any way. |
253 | .IP "ev_tstamp ev_time ()" 4 |
255 | .IP "ev_tstamp ev_time ()" 4 |
254 | .IX Item "ev_tstamp ev_time ()" |
256 | .IX Item "ev_tstamp ev_time ()" |
255 | 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 |
256 | \&\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 |
257 | 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. |
258 | .IP "int ev_version_major ()" 4 |
265 | .IP "int ev_version_major ()" 4 |
259 | .IX Item "int ev_version_major ()" |
266 | .IX Item "int ev_version_major ()" |
260 | .PD 0 |
267 | .PD 0 |
261 | .IP "int ev_version_minor ()" 4 |
268 | .IP "int ev_version_minor ()" 4 |
262 | .IX Item "int ev_version_minor ()" |
269 | .IX Item "int ev_version_minor ()" |
263 | .PD |
270 | .PD |
264 | 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 |
265 | 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 |
266 | \&\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 |
267 | 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 |
268 | version of the library your program was compiled against. |
275 | version of the library your program was compiled against. |
269 | .Sp |
276 | .Sp |
|
|
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 |
270 | 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, |
271 | as this indicates an incompatible change. Minor versions are usually |
281 | as this indicates an incompatible change. Minor versions are usually |
272 | 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 |
273 | not a problem. |
283 | not a problem. |
274 | .Sp |
284 | .Sp |
275 | 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 |
276 | version. |
286 | version. |
… | |
… | |
441 | .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 |
442 | .IX Item "EVBACKEND_SELECT (value 1, portable select backend)" |
452 | .IX Item "EVBACKEND_SELECT (value 1, portable select backend)" |
443 | 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 |
444 | 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, |
445 | 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 |
446 | 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 |
447 | 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. |
448 | .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 |
449 | .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 |
450 | .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)" |
451 | 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 |
452 | 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 |
453 | 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 |
454 | 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. |
455 | .ie n .IP """EVBACKEND_EPOLL"" (value 4, Linux)" 4 |
474 | .ie n .IP """EVBACKEND_EPOLL"" (value 4, Linux)" 4 |
456 | .el .IP "\f(CWEVBACKEND_EPOLL\fR (value 4, Linux)" 4 |
475 | .el .IP "\f(CWEVBACKEND_EPOLL\fR (value 4, Linux)" 4 |
457 | .IX Item "EVBACKEND_EPOLL (value 4, Linux)" |
476 | .IX Item "EVBACKEND_EPOLL (value 4, Linux)" |
458 | 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, |
459 | but it scales phenomenally better. While poll and select usually scale like |
478 | but it scales phenomenally better. While poll and select usually scale |
460 | 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), |
461 | 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. |
462 | .Sp |
484 | .Sp |
463 | 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 |
464 | 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 |
465 | (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 |
466 | 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 |
467 | well if you register events for both fds. |
489 | very well if you register events for both fds. |
468 | .Sp |
490 | .Sp |
469 | Please note that epoll sometimes generates spurious notifications, so you |
491 | Please note that epoll sometimes generates spurious notifications, so you |
470 | 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 |
471 | (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. |
472 | .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 |
473 | .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 |
474 | .IX Item "EVBACKEND_KQUEUE (value 8, most BSD clones)" |
503 | .IX Item "EVBACKEND_KQUEUE (value 8, most BSD clones)" |
475 | 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 |
476 | 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 |
477 | 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 |
478 | 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" |
479 | 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 |
480 | \&\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 |
|
|
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. |
481 | .Sp |
515 | .Sp |
482 | 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 |
483 | 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 |
484 | 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 |
485 | 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 |
486 | 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. |
|
|
522 | .Sp |
|
|
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. |
487 | .ie n .IP """EVBACKEND_DEVPOLL"" (value 16, Solaris 8)" 4 |
531 | .ie n .IP """EVBACKEND_DEVPOLL"" (value 16, Solaris 8)" 4 |
488 | .el .IP "\f(CWEVBACKEND_DEVPOLL\fR (value 16, Solaris 8)" 4 |
532 | .el .IP "\f(CWEVBACKEND_DEVPOLL\fR (value 16, Solaris 8)" 4 |
489 | .IX Item "EVBACKEND_DEVPOLL (value 16, Solaris 8)" |
533 | .IX Item "EVBACKEND_DEVPOLL (value 16, Solaris 8)" |
490 | 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. |
491 | .ie n .IP """EVBACKEND_PORT"" (value 32, Solaris 10)" 4 |
538 | .ie n .IP """EVBACKEND_PORT"" (value 32, Solaris 10)" 4 |
492 | .el .IP "\f(CWEVBACKEND_PORT\fR (value 32, Solaris 10)" 4 |
539 | .el .IP "\f(CWEVBACKEND_PORT\fR (value 32, Solaris 10)" 4 |
493 | .IX Item "EVBACKEND_PORT (value 32, Solaris 10)" |
540 | .IX Item "EVBACKEND_PORT (value 32, Solaris 10)" |
494 | 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, |
495 | 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)). |
496 | .Sp |
543 | .Sp |
497 | 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 |
498 | 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 |
499 | 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 |
|
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549 | file descriptor per loop iteration. For small and medium numbers of file |
|
|
550 | descriptors a \*(L"slow\*(R" \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR or \f(CW\*(C`EVBACKEND_POLL\*(C'\fR backend |
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551 | might perform better. |
500 | .ie n .IP """EVBACKEND_ALL""" 4 |
552 | .ie n .IP """EVBACKEND_ALL""" 4 |
501 | .el .IP "\f(CWEVBACKEND_ALL\fR" 4 |
553 | .el .IP "\f(CWEVBACKEND_ALL\fR" 4 |
502 | .IX Item "EVBACKEND_ALL" |
554 | .IX Item "EVBACKEND_ALL" |
503 | 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 |
504 | 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 |
505 | \&\f(CW\*(C`EVBACKEND_ALL & ~EVBACKEND_KQUEUE\*(C'\fR. |
557 | \&\f(CW\*(C`EVBACKEND_ALL & ~EVBACKEND_KQUEUE\*(C'\fR. |
|
|
558 | .Sp |
|
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559 | It is definitely not recommended to use this flag. |
506 | .RE |
560 | .RE |
507 | .RS 4 |
561 | .RS 4 |
508 | .Sp |
562 | .Sp |
509 | 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 |
510 | 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 |
… | |
… | |
552 | Destroys the default loop again (frees all memory and kernel state |
606 | Destroys the default loop again (frees all memory and kernel state |
553 | 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 |
554 | 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 |
555 | responsibility to either stop all watchers cleanly yoursef \fIbefore\fR |
609 | responsibility to either stop all watchers cleanly yoursef \fIbefore\fR |
556 | 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 |
557 | 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 |
558 | 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). |
559 | .IP "ev_loop_destroy (loop)" 4 |
622 | .IP "ev_loop_destroy (loop)" 4 |
560 | .IX Item "ev_loop_destroy (loop)" |
623 | .IX Item "ev_loop_destroy (loop)" |
561 | 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 |
562 | earlier call to \f(CW\*(C`ev_loop_new\*(C'\fR. |
625 | earlier call to \f(CW\*(C`ev_loop_new\*(C'\fR. |
563 | .IP "ev_default_fork ()" 4 |
626 | .IP "ev_default_fork ()" 4 |
… | |
… | |
604 | .IX Item "ev_tstamp ev_now (loop)" |
667 | .IX Item "ev_tstamp ev_now (loop)" |
605 | 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 |
606 | received events and started processing them. This timestamp does not |
669 | received events and started processing them. This timestamp does not |
607 | 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 |
608 | 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 |
609 | event occuring (or more correctly, libev finding out about it). |
672 | event occurring (or more correctly, libev finding out about it). |
610 | .IP "ev_loop (loop, int flags)" 4 |
673 | .IP "ev_loop (loop, int flags)" 4 |
611 | .IX Item "ev_loop (loop, int flags)" |
674 | .IX Item "ev_loop (loop, int flags)" |
612 | 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 |
613 | 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 |
614 | events. |
677 | events. |
… | |
… | |
634 | 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 |
635 | usually a better approach for this kind of thing. |
698 | usually a better approach for this kind of thing. |
636 | .Sp |
699 | .Sp |
637 | 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: |
638 | .Sp |
701 | .Sp |
639 | .Vb 18 |
702 | .Vb 19 |
|
|
703 | \& - Before the first iteration, call any pending watchers. |
640 | \& * If there are no active watchers (reference count is zero), return. |
704 | \& * If there are no active watchers (reference count is zero), return. |
641 | \& - Queue prepare watchers and then call all outstanding watchers. |
705 | \& - Queue all prepare watchers and then call all outstanding watchers. |
642 | \& - If we have been forked, recreate the kernel state. |
706 | \& - If we have been forked, recreate the kernel state. |
643 | \& - Update the kernel state with all outstanding changes. |
707 | \& - Update the kernel state with all outstanding changes. |
644 | \& - Update the "event loop time". |
708 | \& - Update the "event loop time". |
645 | \& - Calculate for how long to block. |
709 | \& - Calculate for how long to block. |
646 | \& - Block the process, waiting for any events. |
710 | \& - Block the process, waiting for any events. |
… | |
… | |
703 | .Sp |
767 | .Sp |
704 | .Vb 2 |
768 | .Vb 2 |
705 | \& ev_ref (loop); |
769 | \& ev_ref (loop); |
706 | \& ev_signal_stop (loop, &exitsig); |
770 | \& ev_signal_stop (loop, &exitsig); |
707 | .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. |
708 | .SH "ANATOMY OF A WATCHER" |
809 | .SH "ANATOMY OF A WATCHER" |
709 | .IX Header "ANATOMY OF A WATCHER" |
810 | .IX Header "ANATOMY OF A WATCHER" |
710 | 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 |
711 | 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 |
712 | 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: |
… | |
… | |
889 | .IP "bool ev_is_pending (ev_TYPE *watcher)" 4 |
990 | .IP "bool ev_is_pending (ev_TYPE *watcher)" 4 |
890 | .IX Item "bool ev_is_pending (ev_TYPE *watcher)" |
991 | .IX Item "bool ev_is_pending (ev_TYPE *watcher)" |
891 | 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 |
892 | 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 |
893 | 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 |
894 | \&\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 |
895 | 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). |
896 | .IP "callback ev_cb (ev_TYPE *watcher)" 4 |
998 | .IP "callback ev_cb (ev_TYPE *watcher)" 4 |
897 | .IX Item "callback ev_cb (ev_TYPE *watcher)" |
999 | .IX Item "callback ev_cb (ev_TYPE *watcher)" |
898 | Returns the callback currently set on the watcher. |
1000 | Returns the callback currently set on the watcher. |
899 | .IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 |
1001 | .IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 |
900 | .IX Item "ev_cb_set (ev_TYPE *watcher, callback)" |
1002 | .IX Item "ev_cb_set (ev_TYPE *watcher, callback)" |
… | |
… | |
918 | watchers on the same event and make sure one is called first. |
1020 | watchers on the same event and make sure one is called first. |
919 | .Sp |
1021 | .Sp |
920 | If you need to suppress invocation when higher priority events are pending |
1022 | If you need to suppress invocation when higher priority events are pending |
921 | you need to look at \f(CW\*(C`ev_idle\*(C'\fR watchers, which provide this functionality. |
1023 | you need to look at \f(CW\*(C`ev_idle\*(C'\fR watchers, which provide this functionality. |
922 | .Sp |
1024 | .Sp |
|
|
1025 | You \fImust not\fR change the priority of a watcher as long as it is active or |
|
|
1026 | pending. |
|
|
1027 | .Sp |
923 | The default priority used by watchers when no priority has been set is |
1028 | The default priority used by watchers when no priority has been set is |
924 | always \f(CW0\fR, which is supposed to not be too high and not be too low :). |
1029 | always \f(CW0\fR, which is supposed to not be too high and not be too low :). |
925 | .Sp |
1030 | .Sp |
926 | Setting a priority outside the range of \f(CW\*(C`EV_MINPRI\*(C'\fR to \f(CW\*(C`EV_MAXPRI\*(C'\fR is |
1031 | Setting a priority outside the range of \f(CW\*(C`EV_MINPRI\*(C'\fR to \f(CW\*(C`EV_MAXPRI\*(C'\fR is |
927 | fine, as long as you do not mind that the priority value you query might |
1032 | fine, as long as you do not mind that the priority value you query might |
928 | or might not have been adjusted to be within valid range. |
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. |
929 | .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" |
930 | .IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER" |
1045 | .IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER" |
931 | 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 |
932 | 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 |
933 | 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 |
… | |
… | |
1023 | 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 |
1024 | 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 |
1025 | 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 |
1026 | required if you know what you are doing). |
1141 | required if you know what you are doing). |
1027 | .PP |
1142 | .PP |
1028 | You have to be careful with dup'ed file descriptors, though. Some backends |
|
|
1029 | (the linux epoll backend is a notable example) cannot handle dup'ed file |
|
|
1030 | descriptors correctly if you register interest in two or more fds pointing |
|
|
1031 | to the same underlying file/socket/etc. description (that is, they share |
|
|
1032 | the same underlying \*(L"file open\*(R"). |
|
|
1033 | .PP |
|
|
1034 | 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 |
1035 | (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 |
1036 | \&\f(CW\*(C`EVBACKEND_POLL\*(C'\fR). |
1145 | \&\f(CW\*(C`EVBACKEND_POLL\*(C'\fR). |
1037 | .PP |
1146 | .PP |
1038 | 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 |
… | |
… | |
1047 | 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 |
1048 | 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 |
1049 | whether 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 |
1050 | 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 |
1051 | 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" |
1052 | .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 |
1053 | .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)" |
1054 | .PD 0 |
1212 | .PD 0 |
1055 | .IP "ev_io_set (ev_io *, int fd, int events)" 4 |
1213 | .IP "ev_io_set (ev_io *, int fd, int events)" 4 |
1056 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
1214 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
… | |
… | |
1109 | .Ve |
1267 | .Ve |
1110 | .PP |
1268 | .PP |
1111 | 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, |
1112 | 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 |
1113 | 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" |
1114 | .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 |
1115 | .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)" |
1116 | .PD 0 |
1277 | .PD 0 |
1117 | .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 |
1118 | .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)" |
… | |
… | |
1220 | 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 |
1221 | 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 |
1222 | 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 () |
1223 | + 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 |
1224 | 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 |
1225 | roughly 10 seconds later and of course not if you reset your system time |
1386 | roughly 10 seconds later). |
1226 | again). |
|
|
1227 | .PP |
1387 | .PP |
1228 | 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 |
1229 | triggering an event on eahc midnight, local time. |
1389 | triggering an event on each midnight, local time or other, complicated, |
|
|
1390 | rules. |
1230 | .PP |
1391 | .PP |
1231 | 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 |
1232 | 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 |
1233 | 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" |
1234 | .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 |
1235 | .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)" |
1236 | .PD 0 |
1400 | .PD 0 |
1237 | .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 |
1238 | .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)" |
1239 | .PD |
1403 | .PD |
1240 | 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 |
1241 | operation, and we will explain them from simplest to complex: |
1405 | operation, and we will explain them from simplest to complex: |
1242 | .RS 4 |
1406 | .RS 4 |
1243 | .IP "* absolute timer (interval = reschedule_cb = 0)" 4 |
1407 | .IP "* absolute timer (at = time, interval = reschedule_cb = 0)" 4 |
1244 | .IX Item "absolute timer (interval = reschedule_cb = 0)" |
1408 | .IX Item "absolute timer (at = time, interval = reschedule_cb = 0)" |
1245 | 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 |
1246 | \&\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, |
1247 | 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 |
1248 | system time reaches or surpasses this time. |
1412 | system time reaches or surpasses this time. |
1249 | .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 |
1250 | .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)" |
1251 | 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 |
1252 | \&\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) |
1253 | of any time jumps. |
1417 | and then repeat, regardless of any time jumps. |
1254 | .Sp |
1418 | .Sp |
1255 | 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 |
1256 | time: |
1420 | time: |
1257 | .Sp |
1421 | .Sp |
1258 | .Vb 1 |
1422 | .Vb 1 |
… | |
… | |
1265 | by 3600. |
1429 | by 3600. |
1266 | .Sp |
1430 | .Sp |
1267 | 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 |
1268 | \&\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 |
1269 | 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. |
1270 | .IP "* manual reschedule mode (reschedule_cb = callback)" 4 |
1438 | .IP "* manual reschedule mode (at and interval ignored, reschedule_cb = callback)" 4 |
1271 | .IX Item "manual reschedule mode (reschedule_cb = callback)" |
1439 | .IX Item "manual reschedule mode (at and interval ignored, reschedule_cb = callback)" |
1272 | 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 |
1273 | ignored. Instead, each time the periodic watcher gets scheduled, the |
1441 | ignored. Instead, each time the periodic watcher gets scheduled, the |
1274 | 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 |
1275 | current time as second argument. |
1443 | current time as second argument. |
1276 | .Sp |
1444 | .Sp |
1277 | \&\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, |
1278 | 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, |
1279 | 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 |
1280 | starting a prepare watcher). |
1448 | starting an \f(CW\*(C`ev_prepare\*(C'\fR watcher, which is legal). |
1281 | .Sp |
1449 | .Sp |
1282 | 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, |
1283 | ev_tstamp now)\*(C'\fR, e.g.: |
1451 | ev_tstamp now)\*(C'\fR, e.g.: |
1284 | .Sp |
1452 | .Sp |
1285 | .Vb 4 |
1453 | .Vb 4 |
… | |
… | |
1309 | .IX Item "ev_periodic_again (loop, ev_periodic *)" |
1477 | .IX Item "ev_periodic_again (loop, ev_periodic *)" |
1310 | 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 |
1311 | when you changed some parameters or the reschedule callback would return |
1479 | when you changed some parameters or the reschedule callback would return |
1312 | 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 |
1313 | 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. |
1314 | .IP "ev_tstamp interval [read\-write]" 4 |
1489 | .IP "ev_tstamp interval [read\-write]" 4 |
1315 | .IX Item "ev_tstamp interval [read-write]" |
1490 | .IX Item "ev_tstamp interval [read-write]" |
1316 | 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 |
1317 | 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 |
1318 | called. |
1493 | called. |
1319 | .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 |
1320 | .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]" |
1321 | 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 |
1322 | 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 |
1323 | 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. |
1324 | .PP |
1503 | .PP |
1325 | Example: Call a callback every hour, or, more precisely, whenever the |
1504 | Example: Call a callback every hour, or, more precisely, whenever the |
1326 | system clock is divisible by 3600. The callback invocation times have |
1505 | system clock is divisible by 3600. The callback invocation times have |
1327 | potentially a lot of jittering, but good long-term stability. |
1506 | potentially a lot of jittering, but good long-term stability. |
1328 | .PP |
1507 | .PP |
… | |
… | |
1378 | first watcher gets started will libev actually register a signal watcher |
1557 | first watcher gets started will libev actually register a signal watcher |
1379 | 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 |
1380 | 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 |
1381 | 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 |
1382 | \&\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" |
1383 | .IP "ev_signal_init (ev_signal *, callback, int signum)" 4 |
1565 | .IP "ev_signal_init (ev_signal *, callback, int signum)" 4 |
1384 | .IX Item "ev_signal_init (ev_signal *, callback, int signum)" |
1566 | .IX Item "ev_signal_init (ev_signal *, callback, int signum)" |
1385 | .PD 0 |
1567 | .PD 0 |
1386 | .IP "ev_signal_set (ev_signal *, int signum)" 4 |
1568 | .IP "ev_signal_set (ev_signal *, int signum)" 4 |
1387 | .IX Item "ev_signal_set (ev_signal *, int signum)" |
1569 | .IX Item "ev_signal_set (ev_signal *, int signum)" |
… | |
… | |
1394 | .ie n .Sh """ev_child"" \- watch out for process status changes" |
1576 | .ie n .Sh """ev_child"" \- watch out for process status changes" |
1395 | .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" |
1396 | .IX Subsection "ev_child - watch out for process status changes" |
1578 | .IX Subsection "ev_child - watch out for process status changes" |
1397 | 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 |
1398 | 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" |
1399 | .IP "ev_child_init (ev_child *, callback, int pid)" 4 |
1584 | .IP "ev_child_init (ev_child *, callback, int pid)" 4 |
1400 | .IX Item "ev_child_init (ev_child *, callback, int pid)" |
1585 | .IX Item "ev_child_init (ev_child *, callback, int pid)" |
1401 | .PD 0 |
1586 | .PD 0 |
1402 | .IP "ev_child_set (ev_child *, int pid)" 4 |
1587 | .IP "ev_child_set (ev_child *, int pid)" 4 |
1403 | .IX Item "ev_child_set (ev_child *, int pid)" |
1588 | .IX Item "ev_child_set (ev_child *, int pid)" |
… | |
… | |
1468 | 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 |
1469 | 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 |
1470 | 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 |
1471 | 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 |
1472 | 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" |
1473 | .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 |
1474 | .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)" |
1475 | .PD 0 |
1698 | .PD 0 |
1476 | .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 |
1477 | .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)" |
… | |
… | |
1506 | The specified interval. |
1729 | The specified interval. |
1507 | .IP "const char *path [read\-only]" 4 |
1730 | .IP "const char *path [read\-only]" 4 |
1508 | .IX Item "const char *path [read-only]" |
1731 | .IX Item "const char *path [read-only]" |
1509 | The filesystem path that is being watched. |
1732 | The filesystem path that is being watched. |
1510 | .PP |
1733 | .PP |
|
|
1734 | \fIExamples\fR |
|
|
1735 | .IX Subsection "Examples" |
|
|
1736 | .PP |
1511 | 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. |
1512 | .PP |
1738 | .PP |
1513 | .Vb 15 |
1739 | .Vb 15 |
1514 | \& static void |
1740 | \& static void |
1515 | \& passwd_cb (struct ev_loop *loop, ev_stat *w, int revents) |
1741 | \& passwd_cb (struct ev_loop *loop, ev_stat *w, int revents) |
… | |
… | |
1532 | \& ... |
1758 | \& ... |
1533 | \& ev_stat passwd; |
1759 | \& ev_stat passwd; |
1534 | .Ve |
1760 | .Ve |
1535 | .PP |
1761 | .PP |
1536 | .Vb 2 |
1762 | .Vb 2 |
1537 | \& ev_stat_init (&passwd, passwd_cb, "/etc/passwd"); |
1763 | \& ev_stat_init (&passwd, passwd_cb, "/etc/passwd", 0.); |
1538 | \& 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); |
1539 | .Ve |
1803 | .Ve |
1540 | .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..." |
1541 | .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..." |
1542 | .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..." |
1543 | Idle watchers trigger events when no other events of the same or higher |
1807 | Idle watchers trigger events when no other events of the same or higher |
… | |
… | |
1556 | .PP |
1820 | .PP |
1557 | Apart from keeping your process non-blocking (which is a useful |
1821 | Apart from keeping your process non-blocking (which is a useful |
1558 | 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 |
1559 | \&\*(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 |
1560 | 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" |
1561 | .IP "ev_idle_init (ev_signal *, callback)" 4 |
1828 | .IP "ev_idle_init (ev_signal *, callback)" 4 |
1562 | .IX Item "ev_idle_init (ev_signal *, callback)" |
1829 | .IX Item "ev_idle_init (ev_signal *, callback)" |
1563 | 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 |
1564 | 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, |
1565 | believe me. |
1832 | believe me. |
… | |
… | |
1620 | 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 |
1621 | 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 |
1622 | 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 |
1623 | loop from blocking if lower-priority coroutines are active, thus mapping |
1890 | loop from blocking if lower-priority coroutines are active, thus mapping |
1624 | 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" |
1625 | .IP "ev_prepare_init (ev_prepare *, callback)" 4 |
1905 | .IP "ev_prepare_init (ev_prepare *, callback)" 4 |
1626 | .IX Item "ev_prepare_init (ev_prepare *, callback)" |
1906 | .IX Item "ev_prepare_init (ev_prepare *, callback)" |
1627 | .PD 0 |
1907 | .PD 0 |
1628 | .IP "ev_check_init (ev_check *, callback)" 4 |
1908 | .IP "ev_check_init (ev_check *, callback)" 4 |
1629 | .IX Item "ev_check_init (ev_check *, callback)" |
1909 | .IX Item "ev_check_init (ev_check *, callback)" |
1630 | .PD |
1910 | .PD |
1631 | Initialises and configures the prepare or check watcher \- they have no |
1911 | Initialises and configures the prepare or check watcher \- they have no |
1632 | 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 |
1633 | macros, but using them is utterly, utterly and completely pointless. |
1913 | macros, but using them is utterly, utterly and completely pointless. |
1634 | .PP |
1914 | .PP |
1635 | 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 |
1636 | 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, |
1637 | 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 |
1638 | 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. |
1639 | .PP |
1927 | .PP |
1640 | .Vb 2 |
1928 | .Vb 2 |
1641 | \& static ev_io iow [nfd]; |
1929 | \& static ev_io iow [nfd]; |
1642 | \& static ev_timer tw; |
1930 | \& static ev_timer tw; |
1643 | .Ve |
1931 | .Ve |
1644 | .PP |
1932 | .PP |
1645 | .Vb 9 |
1933 | .Vb 4 |
1646 | \& static void |
1934 | \& static void |
1647 | \& io_cb (ev_loop *loop, ev_io *w, int revents) |
1935 | \& io_cb (ev_loop *loop, ev_io *w, int revents) |
1648 | \& { |
1936 | \& { |
1649 | \& // set the relevant poll flags |
|
|
1650 | \& // could also call adns_processreadable etc. here |
|
|
1651 | \& struct pollfd *fd = (struct pollfd *)w->data; |
|
|
1652 | \& if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
|
|
1653 | \& if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
|
|
1654 | \& } |
1937 | \& } |
1655 | .Ve |
1938 | .Ve |
1656 | .PP |
1939 | .PP |
1657 | .Vb 8 |
1940 | .Vb 8 |
1658 | \& // create io watchers for each fd and a timer before blocking |
1941 | \& // create io watchers for each fd and a timer before blocking |
… | |
… | |
1670 | \& ev_timer_init (&tw, 0, timeout * 1e-3); |
1953 | \& ev_timer_init (&tw, 0, timeout * 1e-3); |
1671 | \& ev_timer_start (loop, &tw); |
1954 | \& ev_timer_start (loop, &tw); |
1672 | .Ve |
1955 | .Ve |
1673 | .PP |
1956 | .PP |
1674 | .Vb 6 |
1957 | .Vb 6 |
1675 | \& // create on ev_io per pollfd |
1958 | \& // create one ev_io per pollfd |
1676 | \& for (int i = 0; i < nfd; ++i) |
1959 | \& for (int i = 0; i < nfd; ++i) |
1677 | \& { |
1960 | \& { |
1678 | \& ev_io_init (iow + i, io_cb, fds [i].fd, |
1961 | \& ev_io_init (iow + i, io_cb, fds [i].fd, |
1679 | \& ((fds [i].events & POLLIN ? EV_READ : 0) |
1962 | \& ((fds [i].events & POLLIN ? EV_READ : 0) |
1680 | \& | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
1963 | \& | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
1681 | .Ve |
1964 | .Ve |
1682 | .PP |
1965 | .PP |
1683 | .Vb 5 |
1966 | .Vb 4 |
1684 | \& fds [i].revents = 0; |
1967 | \& fds [i].revents = 0; |
1685 | \& iow [i].data = fds + i; |
|
|
1686 | \& ev_io_start (loop, iow + i); |
1968 | \& ev_io_start (loop, iow + i); |
1687 | \& } |
1969 | \& } |
1688 | \& } |
1970 | \& } |
1689 | .Ve |
1971 | .Ve |
1690 | .PP |
1972 | .PP |
… | |
… | |
1694 | \& adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
1976 | \& adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
1695 | \& { |
1977 | \& { |
1696 | \& ev_timer_stop (loop, &tw); |
1978 | \& ev_timer_stop (loop, &tw); |
1697 | .Ve |
1979 | .Ve |
1698 | .PP |
1980 | .PP |
1699 | .Vb 2 |
1981 | .Vb 8 |
1700 | \& 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 |
1701 | \& ev_io_stop (loop, iow + i); |
1994 | \& ev_io_stop (loop, iow + i); |
|
|
1995 | \& } |
1702 | .Ve |
1996 | .Ve |
1703 | .PP |
1997 | .PP |
1704 | .Vb 2 |
1998 | .Vb 2 |
1705 | \& 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; |
1706 | \& } |
2083 | \& } |
1707 | .Ve |
2084 | .Ve |
1708 | .ie n .Sh """ev_embed"" \- when one backend isn't enough..." |
2085 | .ie n .Sh """ev_embed"" \- when one backend isn't enough..." |
1709 | .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..." |
1710 | .IX Subsection "ev_embed - when one backend isn't enough..." |
2087 | .IX Subsection "ev_embed - when one backend isn't enough..." |
… | |
… | |
1779 | \& ev_embed_start (loop_hi, &embed); |
2156 | \& ev_embed_start (loop_hi, &embed); |
1780 | \& } |
2157 | \& } |
1781 | \& else |
2158 | \& else |
1782 | \& loop_lo = loop_hi; |
2159 | \& loop_lo = loop_hi; |
1783 | .Ve |
2160 | .Ve |
|
|
2161 | .PP |
|
|
2162 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
2163 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1784 | .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 |
1785 | .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)" |
1786 | .PD 0 |
2166 | .PD 0 |
1787 | .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 |
1788 | .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)" |
… | |
… | |
1795 | .IP "ev_embed_sweep (loop, ev_embed *)" 4 |
2175 | .IP "ev_embed_sweep (loop, ev_embed *)" 4 |
1796 | .IX Item "ev_embed_sweep (loop, ev_embed *)" |
2176 | .IX Item "ev_embed_sweep (loop, ev_embed *)" |
1797 | 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 |
1798 | 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 |
1799 | apropriate way for embedded loops. |
2179 | apropriate way for embedded loops. |
1800 | .IP "struct ev_loop *loop [read\-only]" 4 |
2180 | .IP "struct ev_loop *other [read\-only]" 4 |
1801 | .IX Item "struct ev_loop *loop [read-only]" |
2181 | .IX Item "struct ev_loop *other [read-only]" |
1802 | The embedded event loop. |
2182 | The embedded event loop. |
1803 | .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" |
1804 | .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" |
1805 | .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" |
1806 | 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 |
… | |
… | |
1808 | \&\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 |
1809 | 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, |
1810 | 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 |
1811 | \&\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 |
1812 | 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" |
1813 | .IP "ev_fork_init (ev_signal *, callback)" 4 |
2196 | .IP "ev_fork_init (ev_signal *, callback)" 4 |
1814 | .IX Item "ev_fork_init (ev_signal *, callback)" |
2197 | .IX Item "ev_fork_init (ev_signal *, callback)" |
1815 | 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 |
1816 | 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, |
1817 | believe me. |
2200 | believe me. |
… | |
… | |
1978 | .Vb 3 |
2361 | .Vb 3 |
1979 | \& myclass obj; |
2362 | \& myclass obj; |
1980 | \& ev::io iow; |
2363 | \& ev::io iow; |
1981 | \& iow.set <myclass, &myclass::io_cb> (&obj); |
2364 | \& iow.set <myclass, &myclass::io_cb> (&obj); |
1982 | .Ve |
2365 | .Ve |
1983 | .IP "w\->set (void (*function)(watcher &w, int), void *data = 0)" 4 |
2366 | .IP "w\->set<function> (void *data = 0)" 4 |
1984 | .IX Item "w->set (void (*function)(watcher &w, int), void *data = 0)" |
2367 | .IX Item "w->set<function> (void *data = 0)" |
1985 | Also sets a callback, but uses a static method or plain function as |
2368 | Also sets a callback, but uses a static method or plain function as |
1986 | callback. The optional \f(CW\*(C`data\*(C'\fR argument will be stored in the watcher's |
2369 | callback. The optional \f(CW\*(C`data\*(C'\fR argument will be stored in the watcher's |
1987 | \&\f(CW\*(C`data\*(C'\fR member and is free for you to use. |
2370 | \&\f(CW\*(C`data\*(C'\fR member and is free for you to use. |
1988 | .Sp |
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 |
1989 | See the method\-\f(CW\*(C`set\*(C'\fR above for more details. |
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 |
1990 | .IP "w\->set (struct ev_loop *)" 4 |
2382 | .IP "w\->set (struct ev_loop *)" 4 |
1991 | .IX Item "w->set (struct ev_loop *)" |
2383 | .IX Item "w->set (struct ev_loop *)" |
1992 | 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 |
1993 | do this when the watcher is inactive (and not pending either). |
2385 | do this when the watcher is inactive (and not pending either). |
1994 | .IP "w\->set ([args])" 4 |
2386 | .IP "w\->set ([args])" 4 |
… | |
… | |
2002 | 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 |
2003 | constructor already stores the event loop. |
2395 | constructor already stores the event loop. |
2004 | .IP "w\->stop ()" 4 |
2396 | .IP "w\->stop ()" 4 |
2005 | .IX Item "w->stop ()" |
2397 | .IX Item "w->stop ()" |
2006 | 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. |
2007 | .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 |
2008 | .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 |
2009 | .IX Item "w->again () ev::timer, ev::periodic only" |
2401 | .IX Item "w->again () (ev::timer, ev::periodic only)" |
2010 | 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 |
2011 | \&\f(CW\*(C`ev_TYPE_again\*(C'\fR function. |
2403 | \&\f(CW\*(C`ev_TYPE_again\*(C'\fR function. |
2012 | .ie n .IP "w\->sweep () ""ev::embed"" only" 4 |
2404 | .ie n .IP "w\->sweep () (""ev::embed"" only)" 4 |
2013 | .el .IP "w\->sweep () \f(CWev::embed\fR only" 4 |
2405 | .el .IP "w\->sweep () (\f(CWev::embed\fR only)" 4 |
2014 | .IX Item "w->sweep () ev::embed only" |
2406 | .IX Item "w->sweep () (ev::embed only)" |
2015 | Invokes \f(CW\*(C`ev_embed_sweep\*(C'\fR. |
2407 | Invokes \f(CW\*(C`ev_embed_sweep\*(C'\fR. |
2016 | .ie n .IP "w\->update () ""ev::stat"" only" 4 |
2408 | .ie n .IP "w\->update () (""ev::stat"" only)" 4 |
2017 | .el .IP "w\->update () \f(CWev::stat\fR only" 4 |
2409 | .el .IP "w\->update () (\f(CWev::stat\fR only)" 4 |
2018 | .IX Item "w->update () ev::stat only" |
2410 | .IX Item "w->update () (ev::stat only)" |
2019 | Invokes \f(CW\*(C`ev_stat_stat\*(C'\fR. |
2411 | Invokes \f(CW\*(C`ev_stat_stat\*(C'\fR. |
2020 | .RE |
2412 | .RE |
2021 | .RS 4 |
2413 | .RS 4 |
2022 | .RE |
2414 | .RE |
2023 | .PP |
2415 | .PP |
… | |
… | |
2047 | \& io.start (fd, ev::READ); |
2439 | \& io.start (fd, ev::READ); |
2048 | \& } |
2440 | \& } |
2049 | .Ve |
2441 | .Ve |
2050 | .SH "MACRO MAGIC" |
2442 | .SH "MACRO MAGIC" |
2051 | .IX Header "MACRO MAGIC" |
2443 | .IX Header "MACRO MAGIC" |
2052 | 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 |
2053 | \&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines whether (most) functions and |
2445 | of which is \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines whether (most) |
2054 | 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. |
2055 | .PP |
2447 | .PP |
2056 | 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 |
2057 | following macros are defined: |
2449 | following macros are defined: |
2058 | .ie n .IP """EV_A""\fR, \f(CW""EV_A_""" 4 |
2450 | .ie n .IP """EV_A""\fR, \f(CW""EV_A_""" 4 |
2059 | .el .IP "\f(CWEV_A\fR, \f(CWEV_A_\fR" 4 |
2451 | .el .IP "\f(CWEV_A\fR, \f(CWEV_A_\fR" 4 |
… | |
… | |
2118 | Libev can (and often is) directly embedded into host |
2510 | Libev can (and often is) directly embedded into host |
2119 | applications. Examples of applications that embed it include the Deliantra |
2511 | applications. Examples of applications that embed it include the Deliantra |
2120 | 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) |
2121 | and rxvt\-unicode. |
2513 | and rxvt\-unicode. |
2122 | .PP |
2514 | .PP |
2123 | 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 |
2124 | 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 |
2125 | 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 |
2126 | libev somewhere in your source tree). |
2518 | libev somewhere in your source tree). |
2127 | .Sh "\s-1FILESETS\s0" |
2519 | .Sh "\s-1FILESETS\s0" |
2128 | .IX Subsection "FILESETS" |
2520 | .IX Subsection "FILESETS" |
… | |
… | |
2233 | .IX Item "EV_USE_MONOTONIC" |
2625 | .IX Item "EV_USE_MONOTONIC" |
2234 | 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 |
2235 | monotonic clock option at both compiletime and runtime. Otherwise no use |
2627 | monotonic clock option at both compiletime and runtime. Otherwise no use |
2236 | 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 |
2237 | 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 |
2238 | the functionality isn't available is safe, though, althoguh you have |
2630 | the functionality isn't available is safe, though, although you have |
2239 | 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 |
2240 | function is hiding in (often \fI\-lrt\fR). |
2632 | function is hiding in (often \fI\-lrt\fR). |
2241 | .IP "\s-1EV_USE_REALTIME\s0" 4 |
2633 | .IP "\s-1EV_USE_REALTIME\s0" 4 |
2242 | .IX Item "EV_USE_REALTIME" |
2634 | .IX Item "EV_USE_REALTIME" |
2243 | 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 |
2244 | realtime clock option at compiletime (and assume its availability at |
2636 | realtime clock option at compiletime (and assume its availability at |
2245 | 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 |
2246 | 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 |
2247 | (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 |
2248 | 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. |
2249 | .IP "\s-1EV_USE_SELECT\s0" 4 |
2645 | .IP "\s-1EV_USE_SELECT\s0" 4 |
2250 | .IX Item "EV_USE_SELECT" |
2646 | .IX Item "EV_USE_SELECT" |
2251 | 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 |
2252 | \&\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 |
2253 | 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 |
… | |
… | |
2307 | 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 |
2308 | be detected at runtime. |
2704 | be detected at runtime. |
2309 | .IP "\s-1EV_H\s0" 4 |
2705 | .IP "\s-1EV_H\s0" 4 |
2310 | .IX Item "EV_H" |
2706 | .IX Item "EV_H" |
2311 | 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 |
2312 | 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 |
2313 | 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. |
2314 | .IP "\s-1EV_CONFIG_H\s0" 4 |
2710 | .IP "\s-1EV_CONFIG_H\s0" 4 |
2315 | .IX Item "EV_CONFIG_H" |
2711 | .IX Item "EV_CONFIG_H" |
2316 | 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 |
2317 | \&\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 |
2318 | \&\f(CW\*(C`EV_H\*(C'\fR, above. |
2714 | \&\f(CW\*(C`EV_H\*(C'\fR, above. |
2319 | .IP "\s-1EV_EVENT_H\s0" 4 |
2715 | .IP "\s-1EV_EVENT_H\s0" 4 |
2320 | .IX Item "EV_EVENT_H" |
2716 | .IX Item "EV_EVENT_H" |
2321 | 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 |
2322 | 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. |
2323 | .IP "\s-1EV_PROTOTYPES\s0" 4 |
2719 | .IP "\s-1EV_PROTOTYPES\s0" 4 |
2324 | .IX Item "EV_PROTOTYPES" |
2720 | .IX Item "EV_PROTOTYPES" |
2325 | 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 |
2326 | 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 |
2327 | occasionally useful if you want to provide your own wrapper functions |
2723 | occasionally useful if you want to provide your own wrapper functions |
… | |
… | |
2384 | 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 |
2385 | 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 |
2386 | increase this value (\fImust\fR be a power of two). |
2782 | increase this value (\fImust\fR be a power of two). |
2387 | .IP "\s-1EV_INOTIFY_HASHSIZE\s0" 4 |
2783 | .IP "\s-1EV_INOTIFY_HASHSIZE\s0" 4 |
2388 | .IX Item "EV_INOTIFY_HASHSIZE" |
2784 | .IX Item "EV_INOTIFY_HASHSIZE" |
2389 | \&\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 |
2390 | 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), |
2391 | 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 |
2392 | 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 |
2393 | two). |
2789 | two). |
2394 | .IP "\s-1EV_COMMON\s0" 4 |
2790 | .IP "\s-1EV_COMMON\s0" 4 |
… | |
… | |
2413 | .IP "ev_set_cb (ev, cb)" 4 |
2809 | .IP "ev_set_cb (ev, cb)" 4 |
2414 | .IX Item "ev_set_cb (ev, cb)" |
2810 | .IX Item "ev_set_cb (ev, cb)" |
2415 | .PD |
2811 | .PD |
2416 | 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, |
2417 | 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 |
2418 | 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 |
2419 | their default definitions. One possible use for overriding these is to |
2815 | their default definitions. One possible use for overriding these is to |
2420 | 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 |
2421 | 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 |
2422 | .Sh "\s-1EXAMPLES\s0" |
2848 | .Sh "\s-1EXAMPLES\s0" |
2423 | .IX Subsection "EXAMPLES" |
2849 | .IX Subsection "EXAMPLES" |
2424 | For a real-world example of a program the includes libev |
2850 | For a real-world example of a program the includes libev |
2425 | 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 |
2426 | (<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 |
… | |
… | |
2468 | .RS 4 |
2894 | .RS 4 |
2469 | .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 |
2470 | .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)" |
2471 | This means that, when you have a watcher that triggers in one hour and |
2897 | This means that, when you have a watcher that triggers in one hour and |
2472 | there are 100 watchers that would trigger before that then inserting will |
2898 | there are 100 watchers that would trigger before that then inserting will |
2473 | have to skip those 100 watchers. |
2899 | have to skip roughly seven (\f(CW\*(C`ld 100\*(C'\fR) of these watchers. |
2474 | .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 |
2475 | .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)" |
2476 | That means that for changing a timer costs less than removing/adding them |
2902 | That means that changing a timer costs less than removing/adding them |
2477 | as only the relative motion in the event queue has to be paid for. |
2903 | as only the relative motion in the event queue has to be paid for. |
2478 | .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 |
2479 | .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)" |
2480 | These just add the watcher into an array or at the head of a list. |
2906 | These just add the watcher into an array or at the head of a list. |
|
|
2907 | .IP "Stopping check/prepare/idle watchers: O(1)" 4 |
2481 | =item Stopping check/prepare/idle watchers: O(1) |
2908 | .IX Item "Stopping check/prepare/idle watchers: O(1)" |
|
|
2909 | .PD 0 |
2482 | .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 |
2483 | .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 |
2484 | These watchers are stored in lists then need to be walked to find the |
2913 | These watchers are stored in lists then need to be walked to find the |
2485 | correct watcher to remove. The lists are usually short (you don't usually |
2914 | correct watcher to remove. The lists are usually short (you don't usually |
2486 | have many watchers waiting for the same fd or signal). |
2915 | have many watchers waiting for the same fd or signal). |
2487 | .IP "Finding the next timer per loop iteration: O(1)" 4 |
2916 | .IP "Finding the next timer in each loop iteration: O(1)" 4 |
2488 | .IX Item "Finding the next timer per loop iteration: O(1)" |
2917 | .IX Item "Finding the next timer in each loop iteration: O(1)" |
2489 | .PD 0 |
2918 | By virtue of using a binary heap, the next timer is always found at the |
|
|
2919 | beginning of the storage array. |
2490 | .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 |
2491 | .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)" |
2492 | .PD |
|
|
2493 | A change means an I/O watcher gets started or stopped, which requires |
2922 | A change means an I/O watcher gets started or stopped, which requires |
2494 | libev to recalculate its status (and possibly tell the kernel). |
2923 | libev to recalculate its status (and possibly tell the kernel, depending |
2495 | .IP "Activating one watcher: O(1)" 4 |
2924 | on backend and wether \f(CW\*(C`ev_io_set\*(C'\fR was used). |
2496 | .IX Item "Activating one watcher: O(1)" |
2925 | .IP "Activating one watcher (putting it into the pending state): O(1)" 4 |
|
|
2926 | .IX Item "Activating one watcher (putting it into the pending state): O(1)" |
2497 | .PD 0 |
2927 | .PD 0 |
2498 | .IP "Priority handling: O(number_of_priorities)" 4 |
2928 | .IP "Priority handling: O(number_of_priorities)" 4 |
2499 | .IX Item "Priority handling: O(number_of_priorities)" |
2929 | .IX Item "Priority handling: O(number_of_priorities)" |
2500 | .PD |
2930 | .PD |
2501 | Priorities are implemented by allocating some space for each |
2931 | Priorities are implemented by allocating some space for each |
2502 | priority. When doing priority-based operations, libev usually has to |
2932 | priority. When doing priority-based operations, libev usually has to |
2503 | linearly search all the priorities. |
2933 | linearly search all the priorities, but starting/stopping and activating |
|
|
2934 | watchers becomes O(1) w.r.t. prioritiy handling. |
2504 | .RE |
2935 | .RE |
2505 | .RS 4 |
2936 | .RS 4 |
2506 | .SH "AUTHOR" |
2937 | .SH "AUTHOR" |
2507 | .IX Header "AUTHOR" |
2938 | .IX Header "AUTHOR" |
2508 | Marc Lehmann <libev@schmorp.de>. |
2939 | Marc Lehmann <libev@schmorp.de>. |