… | |
… | |
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 "2007-12-22" "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 |
… | |
… | |
196 | \& return 0; |
196 | \& return 0; |
197 | \& } |
197 | \& } |
198 | .Ve |
198 | .Ve |
199 | .SH "DESCRIPTION" |
199 | .SH "DESCRIPTION" |
200 | .IX Header "DESCRIPTION" |
200 | .IX Header "DESCRIPTION" |
|
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201 | The newest version of this document is also available as a html-formatted |
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202 | web page you might find easier to navigate when reading it for the first |
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203 | time: <http://cvs.schmorp.de/libev/ev.html>. |
|
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204 | .PP |
201 | Libev is an event loop: you register interest in certain events (such as a |
205 | Libev is an event loop: you register interest in certain events (such as a |
202 | file descriptor being readable or a timeout occuring), and it will manage |
206 | file descriptor being readable or a timeout occurring), and it will manage |
203 | these event sources and provide your program with events. |
207 | these event sources and provide your program with events. |
204 | .PP |
208 | .PP |
205 | To do this, it must take more or less complete control over your process |
209 | To do this, it must take more or less complete control over your process |
206 | (or thread) by executing the \fIevent loop\fR handler, and will then |
210 | (or thread) by executing the \fIevent loop\fR handler, and will then |
207 | communicate events via a callback mechanism. |
211 | communicate events via a callback mechanism. |
… | |
… | |
239 | Libev represents time as a single floating point number, representing the |
243 | Libev represents time as a single floating point number, representing the |
240 | (fractional) number of seconds since the (\s-1POSIX\s0) epoch (somewhere near |
244 | (fractional) number of seconds since the (\s-1POSIX\s0) epoch (somewhere near |
241 | the beginning of 1970, details are complicated, don't ask). This type is |
245 | the beginning of 1970, details are complicated, don't ask). This type is |
242 | called \f(CW\*(C`ev_tstamp\*(C'\fR, which is what you should use too. It usually aliases |
246 | called \f(CW\*(C`ev_tstamp\*(C'\fR, which is what you should use too. It usually aliases |
243 | to the \f(CW\*(C`double\*(C'\fR type in C, and when you need to do any calculations on |
247 | to the \f(CW\*(C`double\*(C'\fR type in C, and when you need to do any calculations on |
244 | it, you should treat it as such. |
248 | it, you should treat it as some floatingpoint value. Unlike the name |
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249 | component \f(CW\*(C`stamp\*(C'\fR might indicate, it is also used for time differences |
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250 | throughout libev. |
245 | .SH "GLOBAL FUNCTIONS" |
251 | .SH "GLOBAL FUNCTIONS" |
246 | .IX Header "GLOBAL FUNCTIONS" |
252 | .IX Header "GLOBAL FUNCTIONS" |
247 | These functions can be called anytime, even before initialising the |
253 | These functions can be called anytime, even before initialising the |
248 | library in any way. |
254 | library in any way. |
249 | .IP "ev_tstamp ev_time ()" 4 |
255 | .IP "ev_tstamp ev_time ()" 4 |
250 | .IX Item "ev_tstamp ev_time ()" |
256 | .IX Item "ev_tstamp ev_time ()" |
251 | Returns the current time as libev would use it. Please note that the |
257 | Returns the current time as libev would use it. Please note that the |
252 | \&\f(CW\*(C`ev_now\*(C'\fR function is usually faster and also often returns the timestamp |
258 | \&\f(CW\*(C`ev_now\*(C'\fR function is usually faster and also often returns the timestamp |
253 | you actually want to know. |
259 | you actually want to know. |
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260 | .IP "ev_sleep (ev_tstamp interval)" 4 |
|
|
261 | .IX Item "ev_sleep (ev_tstamp interval)" |
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262 | Sleep for the given interval: The current thread will be blocked until |
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263 | either it is interrupted or the given time interval has passed. Basically |
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264 | this is a subsecond-resolution \f(CW\*(C`sleep ()\*(C'\fR. |
254 | .IP "int ev_version_major ()" 4 |
265 | .IP "int ev_version_major ()" 4 |
255 | .IX Item "int ev_version_major ()" |
266 | .IX Item "int ev_version_major ()" |
256 | .PD 0 |
267 | .PD 0 |
257 | .IP "int ev_version_minor ()" 4 |
268 | .IP "int ev_version_minor ()" 4 |
258 | .IX Item "int ev_version_minor ()" |
269 | .IX Item "int ev_version_minor ()" |
259 | .PD |
270 | .PD |
260 | You can find out the major and minor version numbers of the library |
271 | You can find out the major and minor \s-1ABI\s0 version numbers of the library |
261 | you linked against by calling the functions \f(CW\*(C`ev_version_major\*(C'\fR and |
272 | you linked against by calling the functions \f(CW\*(C`ev_version_major\*(C'\fR and |
262 | \&\f(CW\*(C`ev_version_minor\*(C'\fR. If you want, you can compare against the global |
273 | \&\f(CW\*(C`ev_version_minor\*(C'\fR. If you want, you can compare against the global |
263 | symbols \f(CW\*(C`EV_VERSION_MAJOR\*(C'\fR and \f(CW\*(C`EV_VERSION_MINOR\*(C'\fR, which specify the |
274 | symbols \f(CW\*(C`EV_VERSION_MAJOR\*(C'\fR and \f(CW\*(C`EV_VERSION_MINOR\*(C'\fR, which specify the |
264 | version of the library your program was compiled against. |
275 | version of the library your program was compiled against. |
265 | .Sp |
276 | .Sp |
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|
277 | These version numbers refer to the \s-1ABI\s0 version of the library, not the |
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278 | release version. |
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279 | .Sp |
266 | Usually, it's a good idea to terminate if the major versions mismatch, |
280 | Usually, it's a good idea to terminate if the major versions mismatch, |
267 | as this indicates an incompatible change. Minor versions are usually |
281 | as this indicates an incompatible change. Minor versions are usually |
268 | compatible to older versions, so a larger minor version alone is usually |
282 | compatible to older versions, so a larger minor version alone is usually |
269 | not a problem. |
283 | not a problem. |
270 | .Sp |
284 | .Sp |
271 | Example: Make sure we haven't accidentally been linked against the wrong |
285 | Example: Make sure we haven't accidentally been linked against the wrong |
272 | version. |
286 | version. |
… | |
… | |
450 | lot of inactive fds). It scales similarly to select, i.e. O(total_fds). |
464 | lot of inactive fds). It scales similarly to select, i.e. O(total_fds). |
451 | .ie n .IP """EVBACKEND_EPOLL"" (value 4, Linux)" 4 |
465 | .ie n .IP """EVBACKEND_EPOLL"" (value 4, Linux)" 4 |
452 | .el .IP "\f(CWEVBACKEND_EPOLL\fR (value 4, Linux)" 4 |
466 | .el .IP "\f(CWEVBACKEND_EPOLL\fR (value 4, Linux)" 4 |
453 | .IX Item "EVBACKEND_EPOLL (value 4, Linux)" |
467 | .IX Item "EVBACKEND_EPOLL (value 4, Linux)" |
454 | For few fds, this backend is a bit little slower than poll and select, |
468 | For few fds, this backend is a bit little slower than poll and select, |
455 | but it scales phenomenally better. While poll and select usually scale like |
469 | but it scales phenomenally better. While poll and select usually scale |
456 | O(total_fds) where n is the total number of fds (or the highest fd), epoll scales |
470 | like O(total_fds) where n is the total number of fds (or the highest fd), |
457 | either O(1) or O(active_fds). |
471 | epoll scales either O(1) or O(active_fds). The epoll design has a number |
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472 | of shortcomings, such as silently dropping events in some hard-to-detect |
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473 | cases and rewiring a syscall per fd change, no fork support and bad |
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474 | support for dup: |
458 | .Sp |
475 | .Sp |
459 | While stopping and starting an I/O watcher in the same iteration will |
476 | While stopping, setting and starting an I/O watcher in the same iteration |
460 | result in some caching, there is still a syscall per such incident |
477 | will result in some caching, there is still a syscall per such incident |
461 | (because the fd could point to a different file description now), so its |
478 | (because the fd could point to a different file description now), so its |
462 | best to avoid that. Also, \fIdup()\fRed file descriptors might not work very |
479 | best to avoid that. Also, \f(CW\*(C`dup ()\*(C'\fR'ed file descriptors might not work |
463 | well if you register events for both fds. |
480 | very well if you register events for both fds. |
464 | .Sp |
481 | .Sp |
465 | Please note that epoll sometimes generates spurious notifications, so you |
482 | Please note that epoll sometimes generates spurious notifications, so you |
466 | need to use non-blocking I/O or other means to avoid blocking when no data |
483 | need to use non-blocking I/O or other means to avoid blocking when no data |
467 | (or space) is available. |
484 | (or space) is available. |
468 | .ie n .IP """EVBACKEND_KQUEUE"" (value 8, most \s-1BSD\s0 clones)" 4 |
485 | .ie n .IP """EVBACKEND_KQUEUE"" (value 8, most \s-1BSD\s0 clones)" 4 |
469 | .el .IP "\f(CWEVBACKEND_KQUEUE\fR (value 8, most \s-1BSD\s0 clones)" 4 |
486 | .el .IP "\f(CWEVBACKEND_KQUEUE\fR (value 8, most \s-1BSD\s0 clones)" 4 |
470 | .IX Item "EVBACKEND_KQUEUE (value 8, most BSD clones)" |
487 | .IX Item "EVBACKEND_KQUEUE (value 8, most BSD clones)" |
471 | Kqueue deserves special mention, as at the time of this writing, it |
488 | Kqueue deserves special mention, as at the time of this writing, it |
472 | was broken on all BSDs except NetBSD (usually it doesn't work with |
489 | was broken on all BSDs except NetBSD (usually it doesn't work reliably |
473 | anything but sockets and pipes, except on Darwin, where of course its |
490 | with anything but sockets and pipes, except on Darwin, where of course |
474 | completely useless). For this reason its not being \*(L"autodetected\*(R" |
491 | it's completely useless). For this reason it's not being \*(L"autodetected\*(R" |
475 | unless you explicitly specify it explicitly in the flags (i.e. using |
492 | unless you explicitly specify it explicitly in the flags (i.e. using |
476 | \&\f(CW\*(C`EVBACKEND_KQUEUE\*(C'\fR). |
493 | \&\f(CW\*(C`EVBACKEND_KQUEUE\*(C'\fR) or libev was compiled on a known-to-be-good (\-enough) |
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|
494 | system like NetBSD. |
|
|
495 | .Sp |
|
|
496 | You still can embed kqueue into a normal poll or select backend and use it |
|
|
497 | only for sockets (after having made sure that sockets work with kqueue on |
|
|
498 | the target platform). See \f(CW\*(C`ev_embed\*(C'\fR watchers for more info. |
477 | .Sp |
499 | .Sp |
478 | It scales in the same way as the epoll backend, but the interface to the |
500 | It scales in the same way as the epoll backend, but the interface to the |
479 | kernel is more efficient (which says nothing about its actual speed, of |
501 | kernel is more efficient (which says nothing about its actual speed, of |
480 | course). While starting and stopping an I/O watcher does not cause an |
502 | course). While stopping, setting and starting an I/O watcher does never |
481 | extra syscall as with epoll, it still adds up to four event changes per |
503 | cause an extra syscall as with \f(CW\*(C`EVBACKEND_EPOLL\*(C'\fR, it still adds up to |
482 | incident, so its best to avoid that. |
504 | two event changes per incident, support for \f(CW\*(C`fork ()\*(C'\fR is very bad and it |
|
|
505 | drops fds silently in similarly hard-to-detect cases. |
483 | .ie n .IP """EVBACKEND_DEVPOLL"" (value 16, Solaris 8)" 4 |
506 | .ie n .IP """EVBACKEND_DEVPOLL"" (value 16, Solaris 8)" 4 |
484 | .el .IP "\f(CWEVBACKEND_DEVPOLL\fR (value 16, Solaris 8)" 4 |
507 | .el .IP "\f(CWEVBACKEND_DEVPOLL\fR (value 16, Solaris 8)" 4 |
485 | .IX Item "EVBACKEND_DEVPOLL (value 16, Solaris 8)" |
508 | .IX Item "EVBACKEND_DEVPOLL (value 16, Solaris 8)" |
486 | This is not implemented yet (and might never be). |
509 | This is not implemented yet (and might never be). |
487 | .ie n .IP """EVBACKEND_PORT"" (value 32, Solaris 10)" 4 |
510 | .ie n .IP """EVBACKEND_PORT"" (value 32, Solaris 10)" 4 |
488 | .el .IP "\f(CWEVBACKEND_PORT\fR (value 32, Solaris 10)" 4 |
511 | .el .IP "\f(CWEVBACKEND_PORT\fR (value 32, Solaris 10)" 4 |
489 | .IX Item "EVBACKEND_PORT (value 32, Solaris 10)" |
512 | .IX Item "EVBACKEND_PORT (value 32, Solaris 10)" |
490 | This uses the Solaris 10 port mechanism. As with everything on Solaris, |
513 | This uses the Solaris 10 event port mechanism. As with everything on Solaris, |
491 | it's really slow, but it still scales very well (O(active_fds)). |
514 | it's really slow, but it still scales very well (O(active_fds)). |
492 | .Sp |
515 | .Sp |
493 | Please note that solaris ports can result in a lot of spurious |
516 | Please note that solaris event ports can deliver a lot of spurious |
494 | notifications, so you need to use non-blocking I/O or other means to avoid |
517 | notifications, so you need to use non-blocking I/O or other means to avoid |
495 | blocking when no data (or space) is available. |
518 | blocking when no data (or space) is available. |
496 | .ie n .IP """EVBACKEND_ALL""" 4 |
519 | .ie n .IP """EVBACKEND_ALL""" 4 |
497 | .el .IP "\f(CWEVBACKEND_ALL\fR" 4 |
520 | .el .IP "\f(CWEVBACKEND_ALL\fR" 4 |
498 | .IX Item "EVBACKEND_ALL" |
521 | .IX Item "EVBACKEND_ALL" |
… | |
… | |
548 | Destroys the default loop again (frees all memory and kernel state |
571 | Destroys the default loop again (frees all memory and kernel state |
549 | etc.). None of the active event watchers will be stopped in the normal |
572 | etc.). None of the active event watchers will be stopped in the normal |
550 | sense, so e.g. \f(CW\*(C`ev_is_active\*(C'\fR might still return true. It is your |
573 | sense, so e.g. \f(CW\*(C`ev_is_active\*(C'\fR might still return true. It is your |
551 | responsibility to either stop all watchers cleanly yoursef \fIbefore\fR |
574 | responsibility to either stop all watchers cleanly yoursef \fIbefore\fR |
552 | calling this function, or cope with the fact afterwards (which is usually |
575 | calling this function, or cope with the fact afterwards (which is usually |
553 | the easiest thing, youc na just ignore the watchers and/or \f(CW\*(C`free ()\*(C'\fR them |
576 | the easiest thing, you can just ignore the watchers and/or \f(CW\*(C`free ()\*(C'\fR them |
554 | for example). |
577 | for example). |
|
|
578 | .Sp |
|
|
579 | Note that certain global state, such as signal state, will not be freed by |
|
|
580 | this function, and related watchers (such as signal and child watchers) |
|
|
581 | would need to be stopped manually. |
|
|
582 | .Sp |
|
|
583 | In general it is not advisable to call this function except in the |
|
|
584 | rare occasion where you really need to free e.g. the signal handling |
|
|
585 | pipe fds. If you need dynamically allocated loops it is better to use |
|
|
586 | \&\f(CW\*(C`ev_loop_new\*(C'\fR and \f(CW\*(C`ev_loop_destroy\*(C'\fR). |
555 | .IP "ev_loop_destroy (loop)" 4 |
587 | .IP "ev_loop_destroy (loop)" 4 |
556 | .IX Item "ev_loop_destroy (loop)" |
588 | .IX Item "ev_loop_destroy (loop)" |
557 | Like \f(CW\*(C`ev_default_destroy\*(C'\fR, but destroys an event loop created by an |
589 | Like \f(CW\*(C`ev_default_destroy\*(C'\fR, but destroys an event loop created by an |
558 | earlier call to \f(CW\*(C`ev_loop_new\*(C'\fR. |
590 | earlier call to \f(CW\*(C`ev_loop_new\*(C'\fR. |
559 | .IP "ev_default_fork ()" 4 |
591 | .IP "ev_default_fork ()" 4 |
… | |
… | |
600 | .IX Item "ev_tstamp ev_now (loop)" |
632 | .IX Item "ev_tstamp ev_now (loop)" |
601 | Returns the current \*(L"event loop time\*(R", which is the time the event loop |
633 | Returns the current \*(L"event loop time\*(R", which is the time the event loop |
602 | received events and started processing them. This timestamp does not |
634 | received events and started processing them. This timestamp does not |
603 | change as long as callbacks are being processed, and this is also the base |
635 | change as long as callbacks are being processed, and this is also the base |
604 | time used for relative timers. You can treat it as the timestamp of the |
636 | time used for relative timers. You can treat it as the timestamp of the |
605 | event occuring (or more correctly, libev finding out about it). |
637 | event occurring (or more correctly, libev finding out about it). |
606 | .IP "ev_loop (loop, int flags)" 4 |
638 | .IP "ev_loop (loop, int flags)" 4 |
607 | .IX Item "ev_loop (loop, int flags)" |
639 | .IX Item "ev_loop (loop, int flags)" |
608 | Finally, this is it, the event handler. This function usually is called |
640 | Finally, this is it, the event handler. This function usually is called |
609 | after you initialised all your watchers and you want to start handling |
641 | after you initialised all your watchers and you want to start handling |
610 | events. |
642 | events. |
… | |
… | |
630 | libev watchers. However, a pair of \f(CW\*(C`ev_prepare\*(C'\fR/\f(CW\*(C`ev_check\*(C'\fR watchers is |
662 | libev watchers. However, a pair of \f(CW\*(C`ev_prepare\*(C'\fR/\f(CW\*(C`ev_check\*(C'\fR watchers is |
631 | usually a better approach for this kind of thing. |
663 | usually a better approach for this kind of thing. |
632 | .Sp |
664 | .Sp |
633 | Here are the gory details of what \f(CW\*(C`ev_loop\*(C'\fR does: |
665 | Here are the gory details of what \f(CW\*(C`ev_loop\*(C'\fR does: |
634 | .Sp |
666 | .Sp |
635 | .Vb 18 |
667 | .Vb 19 |
|
|
668 | \& - Before the first iteration, call any pending watchers. |
636 | \& * If there are no active watchers (reference count is zero), return. |
669 | \& * If there are no active watchers (reference count is zero), return. |
637 | \& - Queue prepare watchers and then call all outstanding watchers. |
670 | \& - Queue all prepare watchers and then call all outstanding watchers. |
638 | \& - If we have been forked, recreate the kernel state. |
671 | \& - If we have been forked, recreate the kernel state. |
639 | \& - Update the kernel state with all outstanding changes. |
672 | \& - Update the kernel state with all outstanding changes. |
640 | \& - Update the "event loop time". |
673 | \& - Update the "event loop time". |
641 | \& - Calculate for how long to block. |
674 | \& - Calculate for how long to block. |
642 | \& - Block the process, waiting for any events. |
675 | \& - Block the process, waiting for any events. |
… | |
… | |
699 | .Sp |
732 | .Sp |
700 | .Vb 2 |
733 | .Vb 2 |
701 | \& ev_ref (loop); |
734 | \& ev_ref (loop); |
702 | \& ev_signal_stop (loop, &exitsig); |
735 | \& ev_signal_stop (loop, &exitsig); |
703 | .Ve |
736 | .Ve |
|
|
737 | .IP "ev_set_io_collect_interval (loop, ev_tstamp interval)" 4 |
|
|
738 | .IX Item "ev_set_io_collect_interval (loop, ev_tstamp interval)" |
|
|
739 | .PD 0 |
|
|
740 | .IP "ev_set_timeout_collect_interval (loop, ev_tstamp interval)" 4 |
|
|
741 | .IX Item "ev_set_timeout_collect_interval (loop, ev_tstamp interval)" |
|
|
742 | .PD |
|
|
743 | These advanced functions influence the time that libev will spend waiting |
|
|
744 | for events. Both are by default \f(CW0\fR, meaning that libev will try to |
|
|
745 | invoke timer/periodic callbacks and I/O callbacks with minimum latency. |
|
|
746 | .Sp |
|
|
747 | Setting these to a higher value (the \f(CW\*(C`interval\*(C'\fR \fImust\fR be >= \f(CW0\fR) |
|
|
748 | allows libev to delay invocation of I/O and timer/periodic callbacks to |
|
|
749 | increase efficiency of loop iterations. |
|
|
750 | .Sp |
|
|
751 | The background is that sometimes your program runs just fast enough to |
|
|
752 | handle one (or very few) event(s) per loop iteration. While this makes |
|
|
753 | the program responsive, it also wastes a lot of \s-1CPU\s0 time to poll for new |
|
|
754 | events, especially with backends like \f(CW\*(C`select ()\*(C'\fR which have a high |
|
|
755 | overhead for the actual polling but can deliver many events at once. |
|
|
756 | .Sp |
|
|
757 | By setting a higher \fIio collect interval\fR you allow libev to spend more |
|
|
758 | time collecting I/O events, so you can handle more events per iteration, |
|
|
759 | at the cost of increasing latency. Timeouts (both \f(CW\*(C`ev_periodic\*(C'\fR and |
|
|
760 | \&\f(CW\*(C`ev_timer\*(C'\fR) will be not affected. Setting this to a non-null bvalue will |
|
|
761 | introduce an additional \f(CW\*(C`ev_sleep ()\*(C'\fR call into most loop iterations. |
|
|
762 | .Sp |
|
|
763 | Likewise, by setting a higher \fItimeout collect interval\fR you allow libev |
|
|
764 | to spend more time collecting timeouts, at the expense of increased |
|
|
765 | latency (the watcher callback will be called later). \f(CW\*(C`ev_io\*(C'\fR watchers |
|
|
766 | will not be affected. Setting this to a non-null value will not introduce |
|
|
767 | any overhead in libev. |
|
|
768 | .Sp |
|
|
769 | Many (busy) programs can usually benefit by setting the io collect |
|
|
770 | interval to a value near \f(CW0.1\fR or so, which is often enough for |
|
|
771 | interactive servers (of course not for games), likewise for timeouts. It |
|
|
772 | usually doesn't make much sense to set it to a lower value than \f(CW0.01\fR, |
|
|
773 | as this approsaches the timing granularity of most systems. |
704 | .SH "ANATOMY OF A WATCHER" |
774 | .SH "ANATOMY OF A WATCHER" |
705 | .IX Header "ANATOMY OF A WATCHER" |
775 | .IX Header "ANATOMY OF A WATCHER" |
706 | A watcher is a structure that you create and register to record your |
776 | A watcher is a structure that you create and register to record your |
707 | interest in some event. For instance, if you want to wait for \s-1STDIN\s0 to |
777 | interest in some event. For instance, if you want to wait for \s-1STDIN\s0 to |
708 | become readable, you would create an \f(CW\*(C`ev_io\*(C'\fR watcher for that: |
778 | become readable, you would create an \f(CW\*(C`ev_io\*(C'\fR watcher for that: |
… | |
… | |
885 | .IP "bool ev_is_pending (ev_TYPE *watcher)" 4 |
955 | .IP "bool ev_is_pending (ev_TYPE *watcher)" 4 |
886 | .IX Item "bool ev_is_pending (ev_TYPE *watcher)" |
956 | .IX Item "bool ev_is_pending (ev_TYPE *watcher)" |
887 | Returns a true value iff the watcher is pending, (i.e. it has outstanding |
957 | Returns a true value iff the watcher is pending, (i.e. it has outstanding |
888 | events but its callback has not yet been invoked). As long as a watcher |
958 | events but its callback has not yet been invoked). As long as a watcher |
889 | is pending (but not active) you must not call an init function on it (but |
959 | is pending (but not active) you must not call an init function on it (but |
890 | \&\f(CW\*(C`ev_TYPE_set\*(C'\fR is safe) and you must make sure the watcher is available to |
960 | \&\f(CW\*(C`ev_TYPE_set\*(C'\fR is safe), you must not change its priority, and you must |
891 | libev (e.g. you cnanot \f(CW\*(C`free ()\*(C'\fR it). |
961 | make sure the watcher is available to libev (e.g. you cannot \f(CW\*(C`free ()\*(C'\fR |
|
|
962 | it). |
892 | .IP "callback ev_cb (ev_TYPE *watcher)" 4 |
963 | .IP "callback ev_cb (ev_TYPE *watcher)" 4 |
893 | .IX Item "callback ev_cb (ev_TYPE *watcher)" |
964 | .IX Item "callback ev_cb (ev_TYPE *watcher)" |
894 | Returns the callback currently set on the watcher. |
965 | Returns the callback currently set on the watcher. |
895 | .IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 |
966 | .IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 |
896 | .IX Item "ev_cb_set (ev_TYPE *watcher, callback)" |
967 | .IX Item "ev_cb_set (ev_TYPE *watcher, callback)" |
… | |
… | |
914 | watchers on the same event and make sure one is called first. |
985 | watchers on the same event and make sure one is called first. |
915 | .Sp |
986 | .Sp |
916 | If you need to suppress invocation when higher priority events are pending |
987 | If you need to suppress invocation when higher priority events are pending |
917 | you need to look at \f(CW\*(C`ev_idle\*(C'\fR watchers, which provide this functionality. |
988 | you need to look at \f(CW\*(C`ev_idle\*(C'\fR watchers, which provide this functionality. |
918 | .Sp |
989 | .Sp |
|
|
990 | You \fImust not\fR change the priority of a watcher as long as it is active or |
|
|
991 | pending. |
|
|
992 | .Sp |
919 | The default priority used by watchers when no priority has been set is |
993 | The default priority used by watchers when no priority has been set is |
920 | always \f(CW0\fR, which is supposed to not be too high and not be too low :). |
994 | always \f(CW0\fR, which is supposed to not be too high and not be too low :). |
921 | .Sp |
995 | .Sp |
922 | Setting a priority outside the range of \f(CW\*(C`EV_MINPRI\*(C'\fR to \f(CW\*(C`EV_MAXPRI\*(C'\fR is |
996 | Setting a priority outside the range of \f(CW\*(C`EV_MINPRI\*(C'\fR to \f(CW\*(C`EV_MAXPRI\*(C'\fR is |
923 | fine, as long as you do not mind that the priority value you query might |
997 | fine, as long as you do not mind that the priority value you query might |
924 | or might not have been adjusted to be within valid range. |
998 | or might not have been adjusted to be within valid range. |
|
|
999 | .IP "ev_invoke (loop, ev_TYPE *watcher, int revents)" 4 |
|
|
1000 | .IX Item "ev_invoke (loop, ev_TYPE *watcher, int revents)" |
|
|
1001 | 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 |
|
|
1002 | \&\f(CW\*(C`loop\*(C'\fR nor \f(CW\*(C`revents\*(C'\fR need to be valid as long as the watcher callback |
|
|
1003 | can deal with that fact. |
|
|
1004 | .IP "int ev_clear_pending (loop, ev_TYPE *watcher)" 4 |
|
|
1005 | .IX Item "int ev_clear_pending (loop, ev_TYPE *watcher)" |
|
|
1006 | If the watcher is pending, this function returns clears its pending status |
|
|
1007 | and returns its \f(CW\*(C`revents\*(C'\fR bitset (as if its callback was invoked). If the |
|
|
1008 | watcher isn't pending it does nothing and returns \f(CW0\fR. |
925 | .Sh "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0" |
1009 | .Sh "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0" |
926 | .IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER" |
1010 | .IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER" |
927 | Each watcher has, by default, a member \f(CW\*(C`void *data\*(C'\fR that you can change |
1011 | Each watcher has, by default, a member \f(CW\*(C`void *data\*(C'\fR that you can change |
928 | and read at any time, libev will completely ignore it. This can be used |
1012 | and read at any time, libev will completely ignore it. This can be used |
929 | to associate arbitrary data with your watcher. If you need more data and |
1013 | to associate arbitrary data with your watcher. If you need more data and |
… | |
… | |
1043 | If you cannot run the fd in non-blocking mode (for example you should not |
1127 | If you cannot run the fd in non-blocking mode (for example you should not |
1044 | play around with an Xlib connection), then you have to seperately re-test |
1128 | play around with an Xlib connection), then you have to seperately re-test |
1045 | whether a file descriptor is really ready with a known-to-be good interface |
1129 | whether a file descriptor is really ready with a known-to-be good interface |
1046 | such as poll (fortunately in our Xlib example, Xlib already does this on |
1130 | such as poll (fortunately in our Xlib example, Xlib already does this on |
1047 | its own, so its quite safe to use). |
1131 | its own, so its quite safe to use). |
|
|
1132 | .PP |
|
|
1133 | \fIThe special problem of disappearing file descriptors\fR |
|
|
1134 | .IX Subsection "The special problem of disappearing file descriptors" |
|
|
1135 | .PP |
|
|
1136 | Some backends (e.g. kqueue, epoll) need to be told about closing a file |
|
|
1137 | descriptor (either by calling \f(CW\*(C`close\*(C'\fR explicitly or by any other means, |
|
|
1138 | such as \f(CW\*(C`dup\*(C'\fR). The reason is that you register interest in some file |
|
|
1139 | descriptor, but when it goes away, the operating system will silently drop |
|
|
1140 | this interest. If another file descriptor with the same number then is |
|
|
1141 | registered with libev, there is no efficient way to see that this is, in |
|
|
1142 | fact, a different file descriptor. |
|
|
1143 | .PP |
|
|
1144 | To avoid having to explicitly tell libev about such cases, libev follows |
|
|
1145 | the following policy: Each time \f(CW\*(C`ev_io_set\*(C'\fR is being called, libev |
|
|
1146 | will assume that this is potentially a new file descriptor, otherwise |
|
|
1147 | it is assumed that the file descriptor stays the same. That means that |
|
|
1148 | 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 |
|
|
1149 | descriptor even if the file descriptor number itself did not change. |
|
|
1150 | .PP |
|
|
1151 | This is how one would do it normally anyway, the important point is that |
|
|
1152 | the libev application should not optimise around libev but should leave |
|
|
1153 | optimisations to libev. |
|
|
1154 | .PP |
|
|
1155 | \fIThe special problem of dup'ed file descriptors\fR |
|
|
1156 | .IX Subsection "The special problem of dup'ed file descriptors" |
|
|
1157 | .PP |
|
|
1158 | Some backends (e.g. epoll), cannot register events for file descriptors, |
|
|
1159 | but only events for the underlying file descriptions. That menas when you |
|
|
1160 | have \f(CW\*(C`dup ()\*(C'\fR'ed file descriptors and register events for them, only one |
|
|
1161 | file descriptor might actually receive events. |
|
|
1162 | .PP |
|
|
1163 | There is no workaorund possible except not registering events |
|
|
1164 | for potentially \f(CW\*(C`dup ()\*(C'\fR'ed file descriptors or to resort to |
|
|
1165 | \&\f(CW\*(C`EVBACKEND_SELECT\*(C'\fR or \f(CW\*(C`EVBACKEND_POLL\*(C'\fR. |
|
|
1166 | .PP |
|
|
1167 | \fIThe special problem of fork\fR |
|
|
1168 | .IX Subsection "The special problem of fork" |
|
|
1169 | .PP |
|
|
1170 | Some backends (epoll, kqueue) do not support \f(CW\*(C`fork ()\*(C'\fR at all or exhibit |
|
|
1171 | useless behaviour. Libev fully supports fork, but needs to be told about |
|
|
1172 | it in the child. |
|
|
1173 | .PP |
|
|
1174 | To support fork in your programs, you either have to call |
|
|
1175 | \&\f(CW\*(C`ev_default_fork ()\*(C'\fR or \f(CW\*(C`ev_loop_fork ()\*(C'\fR after a fork in the child, |
|
|
1176 | enable \f(CW\*(C`EVFLAG_FORKCHECK\*(C'\fR, or resort to \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR or |
|
|
1177 | \&\f(CW\*(C`EVBACKEND_POLL\*(C'\fR. |
|
|
1178 | .PP |
|
|
1179 | \fIWatcher-Specific Functions\fR |
|
|
1180 | .IX Subsection "Watcher-Specific Functions" |
1048 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
1181 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
1049 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
1182 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
1050 | .PD 0 |
1183 | .PD 0 |
1051 | .IP "ev_io_set (ev_io *, int fd, int events)" 4 |
1184 | .IP "ev_io_set (ev_io *, int fd, int events)" 4 |
1052 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
1185 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
… | |
… | |
1105 | .Ve |
1238 | .Ve |
1106 | .PP |
1239 | .PP |
1107 | The callback is guarenteed to be invoked only when its timeout has passed, |
1240 | The callback is guarenteed to be invoked only when its timeout has passed, |
1108 | but if multiple timers become ready during the same loop iteration then |
1241 | but if multiple timers become ready during the same loop iteration then |
1109 | order of execution is undefined. |
1242 | order of execution is undefined. |
|
|
1243 | .PP |
|
|
1244 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1245 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1110 | .IP "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" 4 |
1246 | .IP "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" 4 |
1111 | .IX Item "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" |
1247 | .IX Item "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" |
1112 | .PD 0 |
1248 | .PD 0 |
1113 | .IP "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)" 4 |
1249 | .IP "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)" 4 |
1114 | .IX Item "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)" |
1250 | .IX Item "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)" |
… | |
… | |
1216 | but on wallclock time (absolute time). You can tell a periodic watcher |
1352 | but on wallclock time (absolute time). You can tell a periodic watcher |
1217 | to trigger \*(L"at\*(R" some specific point in time. For example, if you tell a |
1353 | to trigger \*(L"at\*(R" some specific point in time. For example, if you tell a |
1218 | periodic watcher to trigger in 10 seconds (by specifiying e.g. \f(CW\*(C`ev_now () |
1354 | periodic watcher to trigger in 10 seconds (by specifiying e.g. \f(CW\*(C`ev_now () |
1219 | + 10.\*(C'\fR) and then reset your system clock to the last year, then it will |
1355 | + 10.\*(C'\fR) and then reset your system clock to the last year, then it will |
1220 | take a year to trigger the event (unlike an \f(CW\*(C`ev_timer\*(C'\fR, which would trigger |
1356 | take a year to trigger the event (unlike an \f(CW\*(C`ev_timer\*(C'\fR, which would trigger |
1221 | roughly 10 seconds later and of course not if you reset your system time |
1357 | roughly 10 seconds later). |
1222 | again). |
|
|
1223 | .PP |
1358 | .PP |
1224 | They can also be used to implement vastly more complex timers, such as |
1359 | They can also be used to implement vastly more complex timers, such as |
1225 | triggering an event on eahc midnight, local time. |
1360 | triggering an event on each midnight, local time or other, complicated, |
|
|
1361 | rules. |
1226 | .PP |
1362 | .PP |
1227 | As with timers, the callback is guarenteed to be invoked only when the |
1363 | As with timers, the callback is guarenteed to be invoked only when the |
1228 | time (\f(CW\*(C`at\*(C'\fR) has been passed, but if multiple periodic timers become ready |
1364 | time (\f(CW\*(C`at\*(C'\fR) has been passed, but if multiple periodic timers become ready |
1229 | during the same loop iteration then order of execution is undefined. |
1365 | during the same loop iteration then order of execution is undefined. |
|
|
1366 | .PP |
|
|
1367 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1368 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1230 | .IP "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" 4 |
1369 | .IP "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" 4 |
1231 | .IX Item "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" |
1370 | .IX Item "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" |
1232 | .PD 0 |
1371 | .PD 0 |
1233 | .IP "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" 4 |
1372 | .IP "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" 4 |
1234 | .IX Item "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" |
1373 | .IX Item "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" |
1235 | .PD |
1374 | .PD |
1236 | Lots of arguments, lets sort it out... There are basically three modes of |
1375 | Lots of arguments, lets sort it out... There are basically three modes of |
1237 | operation, and we will explain them from simplest to complex: |
1376 | operation, and we will explain them from simplest to complex: |
1238 | .RS 4 |
1377 | .RS 4 |
1239 | .IP "* absolute timer (interval = reschedule_cb = 0)" 4 |
1378 | .IP "* absolute timer (at = time, interval = reschedule_cb = 0)" 4 |
1240 | .IX Item "absolute timer (interval = reschedule_cb = 0)" |
1379 | .IX Item "absolute timer (at = time, interval = reschedule_cb = 0)" |
1241 | In this configuration the watcher triggers an event at the wallclock time |
1380 | In this configuration the watcher triggers an event at the wallclock time |
1242 | \&\f(CW\*(C`at\*(C'\fR and doesn't repeat. It will not adjust when a time jump occurs, |
1381 | \&\f(CW\*(C`at\*(C'\fR and doesn't repeat. It will not adjust when a time jump occurs, |
1243 | that is, if it is to be run at January 1st 2011 then it will run when the |
1382 | that is, if it is to be run at January 1st 2011 then it will run when the |
1244 | system time reaches or surpasses this time. |
1383 | system time reaches or surpasses this time. |
1245 | .IP "* non-repeating interval timer (interval > 0, reschedule_cb = 0)" 4 |
1384 | .IP "* non-repeating interval timer (at = offset, interval > 0, reschedule_cb = 0)" 4 |
1246 | .IX Item "non-repeating interval timer (interval > 0, reschedule_cb = 0)" |
1385 | .IX Item "non-repeating interval timer (at = offset, interval > 0, reschedule_cb = 0)" |
1247 | In this mode the watcher will always be scheduled to time out at the next |
1386 | In this mode the watcher will always be scheduled to time out at the next |
1248 | \&\f(CW\*(C`at + N * interval\*(C'\fR time (for some integer N) and then repeat, regardless |
1387 | \&\f(CW\*(C`at + N * interval\*(C'\fR time (for some integer N, which can also be negative) |
1249 | of any time jumps. |
1388 | and then repeat, regardless of any time jumps. |
1250 | .Sp |
1389 | .Sp |
1251 | This can be used to create timers that do not drift with respect to system |
1390 | This can be used to create timers that do not drift with respect to system |
1252 | time: |
1391 | time: |
1253 | .Sp |
1392 | .Sp |
1254 | .Vb 1 |
1393 | .Vb 1 |
… | |
… | |
1261 | by 3600. |
1400 | by 3600. |
1262 | .Sp |
1401 | .Sp |
1263 | Another way to think about it (for the mathematically inclined) is that |
1402 | Another way to think about it (for the mathematically inclined) is that |
1264 | \&\f(CW\*(C`ev_periodic\*(C'\fR will try to run the callback in this mode at the next possible |
1403 | \&\f(CW\*(C`ev_periodic\*(C'\fR will try to run the callback in this mode at the next possible |
1265 | time where \f(CW\*(C`time = at (mod interval)\*(C'\fR, regardless of any time jumps. |
1404 | time where \f(CW\*(C`time = at (mod interval)\*(C'\fR, regardless of any time jumps. |
|
|
1405 | .Sp |
|
|
1406 | For numerical stability it is preferable that the \f(CW\*(C`at\*(C'\fR value is near |
|
|
1407 | \&\f(CW\*(C`ev_now ()\*(C'\fR (the current time), but there is no range requirement for |
|
|
1408 | this value. |
1266 | .IP "* manual reschedule mode (reschedule_cb = callback)" 4 |
1409 | .IP "* manual reschedule mode (at and interval ignored, reschedule_cb = callback)" 4 |
1267 | .IX Item "manual reschedule mode (reschedule_cb = callback)" |
1410 | .IX Item "manual reschedule mode (at and interval ignored, reschedule_cb = callback)" |
1268 | In this mode the values for \f(CW\*(C`interval\*(C'\fR and \f(CW\*(C`at\*(C'\fR are both being |
1411 | In this mode the values for \f(CW\*(C`interval\*(C'\fR and \f(CW\*(C`at\*(C'\fR are both being |
1269 | ignored. Instead, each time the periodic watcher gets scheduled, the |
1412 | ignored. Instead, each time the periodic watcher gets scheduled, the |
1270 | reschedule callback will be called with the watcher as first, and the |
1413 | reschedule callback will be called with the watcher as first, and the |
1271 | current time as second argument. |
1414 | current time as second argument. |
1272 | .Sp |
1415 | .Sp |
1273 | \&\s-1NOTE:\s0 \fIThis callback \s-1MUST\s0 \s-1NOT\s0 stop or destroy any periodic watcher, |
1416 | \&\s-1NOTE:\s0 \fIThis callback \s-1MUST\s0 \s-1NOT\s0 stop or destroy any periodic watcher, |
1274 | ever, or make any event loop modifications\fR. If you need to stop it, |
1417 | ever, or make any event loop modifications\fR. If you need to stop it, |
1275 | return \f(CW\*(C`now + 1e30\*(C'\fR (or so, fudge fudge) and stop it afterwards (e.g. by |
1418 | return \f(CW\*(C`now + 1e30\*(C'\fR (or so, fudge fudge) and stop it afterwards (e.g. by |
1276 | starting a prepare watcher). |
1419 | starting an \f(CW\*(C`ev_prepare\*(C'\fR watcher, which is legal). |
1277 | .Sp |
1420 | .Sp |
1278 | Its prototype is \f(CW\*(C`ev_tstamp (*reschedule_cb)(struct ev_periodic *w, |
1421 | Its prototype is \f(CW\*(C`ev_tstamp (*reschedule_cb)(struct ev_periodic *w, |
1279 | ev_tstamp now)\*(C'\fR, e.g.: |
1422 | ev_tstamp now)\*(C'\fR, e.g.: |
1280 | .Sp |
1423 | .Sp |
1281 | .Vb 4 |
1424 | .Vb 4 |
… | |
… | |
1305 | .IX Item "ev_periodic_again (loop, ev_periodic *)" |
1448 | .IX Item "ev_periodic_again (loop, ev_periodic *)" |
1306 | Simply stops and restarts the periodic watcher again. This is only useful |
1449 | Simply stops and restarts the periodic watcher again. This is only useful |
1307 | when you changed some parameters or the reschedule callback would return |
1450 | when you changed some parameters or the reschedule callback would return |
1308 | a different time than the last time it was called (e.g. in a crond like |
1451 | a different time than the last time it was called (e.g. in a crond like |
1309 | program when the crontabs have changed). |
1452 | program when the crontabs have changed). |
|
|
1453 | .IP "ev_tstamp offset [read\-write]" 4 |
|
|
1454 | .IX Item "ev_tstamp offset [read-write]" |
|
|
1455 | When repeating, this contains the offset value, otherwise this is the |
|
|
1456 | absolute point in time (the \f(CW\*(C`at\*(C'\fR value passed to \f(CW\*(C`ev_periodic_set\*(C'\fR). |
|
|
1457 | .Sp |
|
|
1458 | Can be modified any time, but changes only take effect when the periodic |
|
|
1459 | timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called. |
1310 | .IP "ev_tstamp interval [read\-write]" 4 |
1460 | .IP "ev_tstamp interval [read\-write]" 4 |
1311 | .IX Item "ev_tstamp interval [read-write]" |
1461 | .IX Item "ev_tstamp interval [read-write]" |
1312 | The current interval value. Can be modified any time, but changes only |
1462 | The current interval value. Can be modified any time, but changes only |
1313 | take effect when the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being |
1463 | take effect when the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being |
1314 | called. |
1464 | called. |
1315 | .IP "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read\-write]" 4 |
1465 | .IP "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read\-write]" 4 |
1316 | .IX Item "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write]" |
1466 | .IX Item "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write]" |
1317 | The current reschedule callback, or \f(CW0\fR, if this functionality is |
1467 | The current reschedule callback, or \f(CW0\fR, if this functionality is |
1318 | switched off. Can be changed any time, but changes only take effect when |
1468 | switched off. Can be changed any time, but changes only take effect when |
1319 | the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called. |
1469 | the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called. |
|
|
1470 | .IP "ev_tstamp at [read\-only]" 4 |
|
|
1471 | .IX Item "ev_tstamp at [read-only]" |
|
|
1472 | When active, contains the absolute time that the watcher is supposed to |
|
|
1473 | trigger next. |
1320 | .PP |
1474 | .PP |
1321 | Example: Call a callback every hour, or, more precisely, whenever the |
1475 | Example: Call a callback every hour, or, more precisely, whenever the |
1322 | system clock is divisible by 3600. The callback invocation times have |
1476 | system clock is divisible by 3600. The callback invocation times have |
1323 | potentially a lot of jittering, but good long-term stability. |
1477 | potentially a lot of jittering, but good long-term stability. |
1324 | .PP |
1478 | .PP |
… | |
… | |
1374 | first watcher gets started will libev actually register a signal watcher |
1528 | first watcher gets started will libev actually register a signal watcher |
1375 | with the kernel (thus it coexists with your own signal handlers as long |
1529 | with the kernel (thus it coexists with your own signal handlers as long |
1376 | as you don't register any with libev). Similarly, when the last signal |
1530 | as you don't register any with libev). Similarly, when the last signal |
1377 | watcher for a signal is stopped libev will reset the signal handler to |
1531 | watcher for a signal is stopped libev will reset the signal handler to |
1378 | \&\s-1SIG_DFL\s0 (regardless of what it was set to before). |
1532 | \&\s-1SIG_DFL\s0 (regardless of what it was set to before). |
|
|
1533 | .PP |
|
|
1534 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1535 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1379 | .IP "ev_signal_init (ev_signal *, callback, int signum)" 4 |
1536 | .IP "ev_signal_init (ev_signal *, callback, int signum)" 4 |
1380 | .IX Item "ev_signal_init (ev_signal *, callback, int signum)" |
1537 | .IX Item "ev_signal_init (ev_signal *, callback, int signum)" |
1381 | .PD 0 |
1538 | .PD 0 |
1382 | .IP "ev_signal_set (ev_signal *, int signum)" 4 |
1539 | .IP "ev_signal_set (ev_signal *, int signum)" 4 |
1383 | .IX Item "ev_signal_set (ev_signal *, int signum)" |
1540 | .IX Item "ev_signal_set (ev_signal *, int signum)" |
… | |
… | |
1390 | .ie n .Sh """ev_child"" \- watch out for process status changes" |
1547 | .ie n .Sh """ev_child"" \- watch out for process status changes" |
1391 | .el .Sh "\f(CWev_child\fP \- watch out for process status changes" |
1548 | .el .Sh "\f(CWev_child\fP \- watch out for process status changes" |
1392 | .IX Subsection "ev_child - watch out for process status changes" |
1549 | .IX Subsection "ev_child - watch out for process status changes" |
1393 | Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to |
1550 | Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to |
1394 | some child status changes (most typically when a child of yours dies). |
1551 | some child status changes (most typically when a child of yours dies). |
|
|
1552 | .PP |
|
|
1553 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1554 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1395 | .IP "ev_child_init (ev_child *, callback, int pid)" 4 |
1555 | .IP "ev_child_init (ev_child *, callback, int pid)" 4 |
1396 | .IX Item "ev_child_init (ev_child *, callback, int pid)" |
1556 | .IX Item "ev_child_init (ev_child *, callback, int pid)" |
1397 | .PD 0 |
1557 | .PD 0 |
1398 | .IP "ev_child_set (ev_child *, int pid)" 4 |
1558 | .IP "ev_child_set (ev_child *, int pid)" 4 |
1399 | .IX Item "ev_child_set (ev_child *, int pid)" |
1559 | .IX Item "ev_child_set (ev_child *, int pid)" |
… | |
… | |
1464 | reader). Inotify will be used to give hints only and should not change the |
1624 | reader). Inotify will be used to give hints only and should not change the |
1465 | semantics of \f(CW\*(C`ev_stat\*(C'\fR watchers, which means that libev sometimes needs |
1625 | semantics of \f(CW\*(C`ev_stat\*(C'\fR watchers, which means that libev sometimes needs |
1466 | to fall back to regular polling again even with inotify, but changes are |
1626 | to fall back to regular polling again even with inotify, but changes are |
1467 | usually detected immediately, and if the file exists there will be no |
1627 | usually detected immediately, and if the file exists there will be no |
1468 | polling. |
1628 | polling. |
|
|
1629 | .PP |
|
|
1630 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1631 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1469 | .IP "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" 4 |
1632 | .IP "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" 4 |
1470 | .IX Item "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" |
1633 | .IX Item "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" |
1471 | .PD 0 |
1634 | .PD 0 |
1472 | .IP "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" 4 |
1635 | .IP "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" 4 |
1473 | .IX Item "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" |
1636 | .IX Item "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" |
… | |
… | |
1552 | .PP |
1715 | .PP |
1553 | Apart from keeping your process non-blocking (which is a useful |
1716 | Apart from keeping your process non-blocking (which is a useful |
1554 | effect on its own sometimes), idle watchers are a good place to do |
1717 | effect on its own sometimes), idle watchers are a good place to do |
1555 | \&\*(L"pseudo\-background processing\*(R", or delay processing stuff to after the |
1718 | \&\*(L"pseudo\-background processing\*(R", or delay processing stuff to after the |
1556 | event loop has handled all outstanding events. |
1719 | event loop has handled all outstanding events. |
|
|
1720 | .PP |
|
|
1721 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1722 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1557 | .IP "ev_idle_init (ev_signal *, callback)" 4 |
1723 | .IP "ev_idle_init (ev_signal *, callback)" 4 |
1558 | .IX Item "ev_idle_init (ev_signal *, callback)" |
1724 | .IX Item "ev_idle_init (ev_signal *, callback)" |
1559 | Initialises and configures the idle watcher \- it has no parameters of any |
1725 | Initialises and configures the idle watcher \- it has no parameters of any |
1560 | kind. There is a \f(CW\*(C`ev_idle_set\*(C'\fR macro, but using it is utterly pointless, |
1726 | kind. There is a \f(CW\*(C`ev_idle_set\*(C'\fR macro, but using it is utterly pointless, |
1561 | believe me. |
1727 | believe me. |
… | |
… | |
1616 | are ready to run (it's actually more complicated: it only runs coroutines |
1782 | are ready to run (it's actually more complicated: it only runs coroutines |
1617 | with priority higher than or equal to the event loop and one coroutine |
1783 | with priority higher than or equal to the event loop and one coroutine |
1618 | of lower priority, but only once, using idle watchers to keep the event |
1784 | of lower priority, but only once, using idle watchers to keep the event |
1619 | loop from blocking if lower-priority coroutines are active, thus mapping |
1785 | loop from blocking if lower-priority coroutines are active, thus mapping |
1620 | low-priority coroutines to idle/background tasks). |
1786 | low-priority coroutines to idle/background tasks). |
|
|
1787 | .PP |
|
|
1788 | It is recommended to give \f(CW\*(C`ev_check\*(C'\fR watchers highest (\f(CW\*(C`EV_MAXPRI\*(C'\fR) |
|
|
1789 | priority, to ensure that they are being run before any other watchers |
|
|
1790 | after the poll. Also, \f(CW\*(C`ev_check\*(C'\fR watchers (and \f(CW\*(C`ev_prepare\*(C'\fR watchers, |
|
|
1791 | too) should not activate (\*(L"feed\*(R") events into libev. While libev fully |
|
|
1792 | supports this, they will be called before other \f(CW\*(C`ev_check\*(C'\fR watchers |
|
|
1793 | did their job. As \f(CW\*(C`ev_check\*(C'\fR watchers are often used to embed other |
|
|
1794 | (non\-libev) event loops those other event loops might be in an unusable |
|
|
1795 | state until their \f(CW\*(C`ev_check\*(C'\fR watcher ran (always remind yourself to |
|
|
1796 | coexist peacefully with others). |
|
|
1797 | .PP |
|
|
1798 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1799 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1621 | .IP "ev_prepare_init (ev_prepare *, callback)" 4 |
1800 | .IP "ev_prepare_init (ev_prepare *, callback)" 4 |
1622 | .IX Item "ev_prepare_init (ev_prepare *, callback)" |
1801 | .IX Item "ev_prepare_init (ev_prepare *, callback)" |
1623 | .PD 0 |
1802 | .PD 0 |
1624 | .IP "ev_check_init (ev_check *, callback)" 4 |
1803 | .IP "ev_check_init (ev_check *, callback)" 4 |
1625 | .IX Item "ev_check_init (ev_check *, callback)" |
1804 | .IX Item "ev_check_init (ev_check *, callback)" |
1626 | .PD |
1805 | .PD |
1627 | Initialises and configures the prepare or check watcher \- they have no |
1806 | Initialises and configures the prepare or check watcher \- they have no |
1628 | parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR |
1807 | parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR |
1629 | macros, but using them is utterly, utterly and completely pointless. |
1808 | macros, but using them is utterly, utterly and completely pointless. |
1630 | .PP |
1809 | .PP |
1631 | Example: To include a library such as adns, you would add \s-1IO\s0 watchers |
1810 | There are a number of principal ways to embed other event loops or modules |
1632 | and a timeout watcher in a prepare handler, as required by libadns, and |
1811 | into libev. Here are some ideas on how to include libadns into libev |
|
|
1812 | (there is a Perl module named \f(CW\*(C`EV::ADNS\*(C'\fR that does this, which you could |
|
|
1813 | use for an actually working example. Another Perl module named \f(CW\*(C`EV::Glib\*(C'\fR |
|
|
1814 | embeds a Glib main context into libev, and finally, \f(CW\*(C`Glib::EV\*(C'\fR embeds \s-1EV\s0 |
|
|
1815 | into the Glib event loop). |
|
|
1816 | .PP |
|
|
1817 | Method 1: Add \s-1IO\s0 watchers and a timeout watcher in a prepare handler, |
1633 | in a check watcher, destroy them and call into libadns. What follows is |
1818 | and in a check watcher, destroy them and call into libadns. What follows |
1634 | pseudo-code only of course: |
1819 | is pseudo-code only of course. This requires you to either use a low |
|
|
1820 | priority for the check watcher or use \f(CW\*(C`ev_clear_pending\*(C'\fR explicitly, as |
|
|
1821 | the callbacks for the IO/timeout watchers might not have been called yet. |
1635 | .PP |
1822 | .PP |
1636 | .Vb 2 |
1823 | .Vb 2 |
1637 | \& static ev_io iow [nfd]; |
1824 | \& static ev_io iow [nfd]; |
1638 | \& static ev_timer tw; |
1825 | \& static ev_timer tw; |
1639 | .Ve |
1826 | .Ve |
1640 | .PP |
1827 | .PP |
1641 | .Vb 9 |
1828 | .Vb 4 |
1642 | \& static void |
1829 | \& static void |
1643 | \& io_cb (ev_loop *loop, ev_io *w, int revents) |
1830 | \& io_cb (ev_loop *loop, ev_io *w, int revents) |
1644 | \& { |
1831 | \& { |
1645 | \& // set the relevant poll flags |
|
|
1646 | \& // could also call adns_processreadable etc. here |
|
|
1647 | \& struct pollfd *fd = (struct pollfd *)w->data; |
|
|
1648 | \& if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
|
|
1649 | \& if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
|
|
1650 | \& } |
1832 | \& } |
1651 | .Ve |
1833 | .Ve |
1652 | .PP |
1834 | .PP |
1653 | .Vb 8 |
1835 | .Vb 8 |
1654 | \& // create io watchers for each fd and a timer before blocking |
1836 | \& // create io watchers for each fd and a timer before blocking |
… | |
… | |
1666 | \& ev_timer_init (&tw, 0, timeout * 1e-3); |
1848 | \& ev_timer_init (&tw, 0, timeout * 1e-3); |
1667 | \& ev_timer_start (loop, &tw); |
1849 | \& ev_timer_start (loop, &tw); |
1668 | .Ve |
1850 | .Ve |
1669 | .PP |
1851 | .PP |
1670 | .Vb 6 |
1852 | .Vb 6 |
1671 | \& // create on ev_io per pollfd |
1853 | \& // create one ev_io per pollfd |
1672 | \& for (int i = 0; i < nfd; ++i) |
1854 | \& for (int i = 0; i < nfd; ++i) |
1673 | \& { |
1855 | \& { |
1674 | \& ev_io_init (iow + i, io_cb, fds [i].fd, |
1856 | \& ev_io_init (iow + i, io_cb, fds [i].fd, |
1675 | \& ((fds [i].events & POLLIN ? EV_READ : 0) |
1857 | \& ((fds [i].events & POLLIN ? EV_READ : 0) |
1676 | \& | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
1858 | \& | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
1677 | .Ve |
1859 | .Ve |
1678 | .PP |
1860 | .PP |
1679 | .Vb 5 |
1861 | .Vb 4 |
1680 | \& fds [i].revents = 0; |
1862 | \& fds [i].revents = 0; |
1681 | \& iow [i].data = fds + i; |
|
|
1682 | \& ev_io_start (loop, iow + i); |
1863 | \& ev_io_start (loop, iow + i); |
1683 | \& } |
1864 | \& } |
1684 | \& } |
1865 | \& } |
1685 | .Ve |
1866 | .Ve |
1686 | .PP |
1867 | .PP |
… | |
… | |
1690 | \& adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
1871 | \& adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
1691 | \& { |
1872 | \& { |
1692 | \& ev_timer_stop (loop, &tw); |
1873 | \& ev_timer_stop (loop, &tw); |
1693 | .Ve |
1874 | .Ve |
1694 | .PP |
1875 | .PP |
1695 | .Vb 2 |
1876 | .Vb 8 |
1696 | \& for (int i = 0; i < nfd; ++i) |
1877 | \& for (int i = 0; i < nfd; ++i) |
|
|
1878 | \& { |
|
|
1879 | \& // set the relevant poll flags |
|
|
1880 | \& // could also call adns_processreadable etc. here |
|
|
1881 | \& struct pollfd *fd = fds + i; |
|
|
1882 | \& int revents = ev_clear_pending (iow + i); |
|
|
1883 | \& if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
|
|
1884 | \& if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
|
|
1885 | .Ve |
|
|
1886 | .PP |
|
|
1887 | .Vb 3 |
|
|
1888 | \& // now stop the watcher |
1697 | \& ev_io_stop (loop, iow + i); |
1889 | \& ev_io_stop (loop, iow + i); |
|
|
1890 | \& } |
1698 | .Ve |
1891 | .Ve |
1699 | .PP |
1892 | .PP |
1700 | .Vb 2 |
1893 | .Vb 2 |
1701 | \& adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
1894 | \& adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
|
|
1895 | \& } |
|
|
1896 | .Ve |
|
|
1897 | .PP |
|
|
1898 | Method 2: This would be just like method 1, but you run \f(CW\*(C`adns_afterpoll\*(C'\fR |
|
|
1899 | in the prepare watcher and would dispose of the check watcher. |
|
|
1900 | .PP |
|
|
1901 | Method 3: If the module to be embedded supports explicit event |
|
|
1902 | notification (adns does), you can also make use of the actual watcher |
|
|
1903 | callbacks, and only destroy/create the watchers in the prepare watcher. |
|
|
1904 | .PP |
|
|
1905 | .Vb 5 |
|
|
1906 | \& static void |
|
|
1907 | \& timer_cb (EV_P_ ev_timer *w, int revents) |
|
|
1908 | \& { |
|
|
1909 | \& adns_state ads = (adns_state)w->data; |
|
|
1910 | \& update_now (EV_A); |
|
|
1911 | .Ve |
|
|
1912 | .PP |
|
|
1913 | .Vb 2 |
|
|
1914 | \& adns_processtimeouts (ads, &tv_now); |
|
|
1915 | \& } |
|
|
1916 | .Ve |
|
|
1917 | .PP |
|
|
1918 | .Vb 5 |
|
|
1919 | \& static void |
|
|
1920 | \& io_cb (EV_P_ ev_io *w, int revents) |
|
|
1921 | \& { |
|
|
1922 | \& adns_state ads = (adns_state)w->data; |
|
|
1923 | \& update_now (EV_A); |
|
|
1924 | .Ve |
|
|
1925 | .PP |
|
|
1926 | .Vb 3 |
|
|
1927 | \& if (revents & EV_READ ) adns_processreadable (ads, w->fd, &tv_now); |
|
|
1928 | \& if (revents & EV_WRITE) adns_processwriteable (ads, w->fd, &tv_now); |
|
|
1929 | \& } |
|
|
1930 | .Ve |
|
|
1931 | .PP |
|
|
1932 | .Vb 1 |
|
|
1933 | \& // do not ever call adns_afterpoll |
|
|
1934 | .Ve |
|
|
1935 | .PP |
|
|
1936 | Method 4: Do not use a prepare or check watcher because the module you |
|
|
1937 | want to embed is too inflexible to support it. Instead, youc na override |
|
|
1938 | their poll function. The drawback with this solution is that the main |
|
|
1939 | loop is now no longer controllable by \s-1EV\s0. The \f(CW\*(C`Glib::EV\*(C'\fR module does |
|
|
1940 | this. |
|
|
1941 | .PP |
|
|
1942 | .Vb 4 |
|
|
1943 | \& static gint |
|
|
1944 | \& event_poll_func (GPollFD *fds, guint nfds, gint timeout) |
|
|
1945 | \& { |
|
|
1946 | \& int got_events = 0; |
|
|
1947 | .Ve |
|
|
1948 | .PP |
|
|
1949 | .Vb 2 |
|
|
1950 | \& for (n = 0; n < nfds; ++n) |
|
|
1951 | \& // create/start io watcher that sets the relevant bits in fds[n] and increment got_events |
|
|
1952 | .Ve |
|
|
1953 | .PP |
|
|
1954 | .Vb 2 |
|
|
1955 | \& if (timeout >= 0) |
|
|
1956 | \& // create/start timer |
|
|
1957 | .Ve |
|
|
1958 | .PP |
|
|
1959 | .Vb 2 |
|
|
1960 | \& // poll |
|
|
1961 | \& ev_loop (EV_A_ 0); |
|
|
1962 | .Ve |
|
|
1963 | .PP |
|
|
1964 | .Vb 3 |
|
|
1965 | \& // stop timer again |
|
|
1966 | \& if (timeout >= 0) |
|
|
1967 | \& ev_timer_stop (EV_A_ &to); |
|
|
1968 | .Ve |
|
|
1969 | .PP |
|
|
1970 | .Vb 3 |
|
|
1971 | \& // stop io watchers again - their callbacks should have set |
|
|
1972 | \& for (n = 0; n < nfds; ++n) |
|
|
1973 | \& ev_io_stop (EV_A_ iow [n]); |
|
|
1974 | .Ve |
|
|
1975 | .PP |
|
|
1976 | .Vb 2 |
|
|
1977 | \& return got_events; |
1702 | \& } |
1978 | \& } |
1703 | .Ve |
1979 | .Ve |
1704 | .ie n .Sh """ev_embed"" \- when one backend isn't enough..." |
1980 | .ie n .Sh """ev_embed"" \- when one backend isn't enough..." |
1705 | .el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..." |
1981 | .el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..." |
1706 | .IX Subsection "ev_embed - when one backend isn't enough..." |
1982 | .IX Subsection "ev_embed - when one backend isn't enough..." |
… | |
… | |
1775 | \& ev_embed_start (loop_hi, &embed); |
2051 | \& ev_embed_start (loop_hi, &embed); |
1776 | \& } |
2052 | \& } |
1777 | \& else |
2053 | \& else |
1778 | \& loop_lo = loop_hi; |
2054 | \& loop_lo = loop_hi; |
1779 | .Ve |
2055 | .Ve |
|
|
2056 | .PP |
|
|
2057 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
2058 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1780 | .IP "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
2059 | .IP "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
1781 | .IX Item "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" |
2060 | .IX Item "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" |
1782 | .PD 0 |
2061 | .PD 0 |
1783 | .IP "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
2062 | .IP "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
1784 | .IX Item "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" |
2063 | .IX Item "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" |
… | |
… | |
1791 | .IP "ev_embed_sweep (loop, ev_embed *)" 4 |
2070 | .IP "ev_embed_sweep (loop, ev_embed *)" 4 |
1792 | .IX Item "ev_embed_sweep (loop, ev_embed *)" |
2071 | .IX Item "ev_embed_sweep (loop, ev_embed *)" |
1793 | Make a single, non-blocking sweep over the embedded loop. This works |
2072 | Make a single, non-blocking sweep over the embedded loop. This works |
1794 | similarly to \f(CW\*(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\*(C'\fR, but in the most |
2073 | similarly to \f(CW\*(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\*(C'\fR, but in the most |
1795 | apropriate way for embedded loops. |
2074 | apropriate way for embedded loops. |
1796 | .IP "struct ev_loop *loop [read\-only]" 4 |
2075 | .IP "struct ev_loop *other [read\-only]" 4 |
1797 | .IX Item "struct ev_loop *loop [read-only]" |
2076 | .IX Item "struct ev_loop *other [read-only]" |
1798 | The embedded event loop. |
2077 | The embedded event loop. |
1799 | .ie n .Sh """ev_fork"" \- the audacity to resume the event loop after a fork" |
2078 | .ie n .Sh """ev_fork"" \- the audacity to resume the event loop after a fork" |
1800 | .el .Sh "\f(CWev_fork\fP \- the audacity to resume the event loop after a fork" |
2079 | .el .Sh "\f(CWev_fork\fP \- the audacity to resume the event loop after a fork" |
1801 | .IX Subsection "ev_fork - the audacity to resume the event loop after a fork" |
2080 | .IX Subsection "ev_fork - the audacity to resume the event loop after a fork" |
1802 | Fork watchers are called when a \f(CW\*(C`fork ()\*(C'\fR was detected (usually because |
2081 | Fork watchers are called when a \f(CW\*(C`fork ()\*(C'\fR was detected (usually because |
… | |
… | |
1804 | \&\f(CW\*(C`ev_default_fork\*(C'\fR or \f(CW\*(C`ev_loop_fork\*(C'\fR). The invocation is done before the |
2083 | \&\f(CW\*(C`ev_default_fork\*(C'\fR or \f(CW\*(C`ev_loop_fork\*(C'\fR). The invocation is done before the |
1805 | event loop blocks next and before \f(CW\*(C`ev_check\*(C'\fR watchers are being called, |
2084 | event loop blocks next and before \f(CW\*(C`ev_check\*(C'\fR watchers are being called, |
1806 | and only in the child after the fork. If whoever good citizen calling |
2085 | and only in the child after the fork. If whoever good citizen calling |
1807 | \&\f(CW\*(C`ev_default_fork\*(C'\fR cheats and calls it in the wrong process, the fork |
2086 | \&\f(CW\*(C`ev_default_fork\*(C'\fR cheats and calls it in the wrong process, the fork |
1808 | handlers will be invoked, too, of course. |
2087 | handlers will be invoked, too, of course. |
|
|
2088 | .PP |
|
|
2089 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
2090 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1809 | .IP "ev_fork_init (ev_signal *, callback)" 4 |
2091 | .IP "ev_fork_init (ev_signal *, callback)" 4 |
1810 | .IX Item "ev_fork_init (ev_signal *, callback)" |
2092 | .IX Item "ev_fork_init (ev_signal *, callback)" |
1811 | Initialises and configures the fork watcher \- it has no parameters of any |
2093 | Initialises and configures the fork watcher \- it has no parameters of any |
1812 | kind. There is a \f(CW\*(C`ev_fork_set\*(C'\fR macro, but using it is utterly pointless, |
2094 | kind. There is a \f(CW\*(C`ev_fork_set\*(C'\fR macro, but using it is utterly pointless, |
1813 | believe me. |
2095 | believe me. |
… | |
… | |
1890 | .PP |
2172 | .PP |
1891 | .Vb 1 |
2173 | .Vb 1 |
1892 | \& #include <ev++.h> |
2174 | \& #include <ev++.h> |
1893 | .Ve |
2175 | .Ve |
1894 | .PP |
2176 | .PP |
1895 | (it is not installed by default). This automatically includes \fIev.h\fR |
2177 | This automatically includes \fIev.h\fR and puts all of its definitions (many |
1896 | and puts all of its definitions (many of them macros) into the global |
2178 | of them macros) into the global namespace. All \*(C+ specific things are |
1897 | namespace. All \*(C+ specific things are put into the \f(CW\*(C`ev\*(C'\fR namespace. |
2179 | put into the \f(CW\*(C`ev\*(C'\fR namespace. It should support all the same embedding |
|
|
2180 | options as \fIev.h\fR, most notably \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. |
1898 | .PP |
2181 | .PP |
1899 | It should support all the same embedding options as \fIev.h\fR, most notably |
2182 | Care has been taken to keep the overhead low. The only data member the \*(C+ |
1900 | \&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. |
2183 | classes add (compared to plain C\-style watchers) is the event loop pointer |
|
|
2184 | that the watcher is associated with (or no additional members at all if |
|
|
2185 | you disable \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR when embedding libev). |
|
|
2186 | .PP |
|
|
2187 | Currently, functions, and static and non-static member functions can be |
|
|
2188 | used as callbacks. Other types should be easy to add as long as they only |
|
|
2189 | need one additional pointer for context. If you need support for other |
|
|
2190 | types of functors please contact the author (preferably after implementing |
|
|
2191 | it). |
1901 | .PP |
2192 | .PP |
1902 | Here is a list of things available in the \f(CW\*(C`ev\*(C'\fR namespace: |
2193 | Here is a list of things available in the \f(CW\*(C`ev\*(C'\fR namespace: |
1903 | .ie n .IP """ev::READ""\fR, \f(CW""ev::WRITE"" etc." 4 |
2194 | .ie n .IP """ev::READ""\fR, \f(CW""ev::WRITE"" etc." 4 |
1904 | .el .IP "\f(CWev::READ\fR, \f(CWev::WRITE\fR etc." 4 |
2195 | .el .IP "\f(CWev::READ\fR, \f(CWev::WRITE\fR etc." 4 |
1905 | .IX Item "ev::READ, ev::WRITE etc." |
2196 | .IX Item "ev::READ, ev::WRITE etc." |
… | |
… | |
1917 | which is called \f(CW\*(C`ev::sig\*(C'\fR to avoid clashes with the \f(CW\*(C`signal\*(C'\fR macro |
2208 | which is called \f(CW\*(C`ev::sig\*(C'\fR to avoid clashes with the \f(CW\*(C`signal\*(C'\fR macro |
1918 | defines by many implementations. |
2209 | defines by many implementations. |
1919 | .Sp |
2210 | .Sp |
1920 | All of those classes have these methods: |
2211 | All of those classes have these methods: |
1921 | .RS 4 |
2212 | .RS 4 |
1922 | .IP "ev::TYPE::TYPE (object *, object::method *)" 4 |
2213 | .IP "ev::TYPE::TYPE ()" 4 |
1923 | .IX Item "ev::TYPE::TYPE (object *, object::method *)" |
2214 | .IX Item "ev::TYPE::TYPE ()" |
1924 | .PD 0 |
2215 | .PD 0 |
1925 | .IP "ev::TYPE::TYPE (object *, object::method *, struct ev_loop *)" 4 |
2216 | .IP "ev::TYPE::TYPE (struct ev_loop *)" 4 |
1926 | .IX Item "ev::TYPE::TYPE (object *, object::method *, struct ev_loop *)" |
2217 | .IX Item "ev::TYPE::TYPE (struct ev_loop *)" |
1927 | .IP "ev::TYPE::~TYPE" 4 |
2218 | .IP "ev::TYPE::~TYPE" 4 |
1928 | .IX Item "ev::TYPE::~TYPE" |
2219 | .IX Item "ev::TYPE::~TYPE" |
1929 | .PD |
2220 | .PD |
1930 | The constructor takes a pointer to an object and a method pointer to |
2221 | The constructor (optionally) takes an event loop to associate the watcher |
1931 | the event handler callback to call in this class. The constructor calls |
2222 | with. If it is omitted, it will use \f(CW\*(C`EV_DEFAULT\*(C'\fR. |
1932 | \&\f(CW\*(C`ev_init\*(C'\fR for you, which means you have to call the \f(CW\*(C`set\*(C'\fR method |
2223 | .Sp |
1933 | before starting it. If you do not specify a loop then the constructor |
2224 | The constructor calls \f(CW\*(C`ev_init\*(C'\fR for you, which means you have to call the |
1934 | automatically associates the default loop with this watcher. |
2225 | \&\f(CW\*(C`set\*(C'\fR method before starting it. |
|
|
2226 | .Sp |
|
|
2227 | It will not set a callback, however: You have to call the templated \f(CW\*(C`set\*(C'\fR |
|
|
2228 | method to set a callback before you can start the watcher. |
|
|
2229 | .Sp |
|
|
2230 | (The reason why you have to use a method is a limitation in \*(C+ which does |
|
|
2231 | not allow explicit template arguments for constructors). |
1935 | .Sp |
2232 | .Sp |
1936 | The destructor automatically stops the watcher if it is active. |
2233 | The destructor automatically stops the watcher if it is active. |
|
|
2234 | .IP "w\->set<class, &class::method> (object *)" 4 |
|
|
2235 | .IX Item "w->set<class, &class::method> (object *)" |
|
|
2236 | This method sets the callback method to call. The method has to have a |
|
|
2237 | signature of \f(CW\*(C`void (*)(ev_TYPE &, int)\*(C'\fR, it receives the watcher as |
|
|
2238 | first argument and the \f(CW\*(C`revents\*(C'\fR as second. The object must be given as |
|
|
2239 | parameter and is stored in the \f(CW\*(C`data\*(C'\fR member of the watcher. |
|
|
2240 | .Sp |
|
|
2241 | This method synthesizes efficient thunking code to call your method from |
|
|
2242 | the C callback that libev requires. If your compiler can inline your |
|
|
2243 | callback (i.e. it is visible to it at the place of the \f(CW\*(C`set\*(C'\fR call and |
|
|
2244 | your compiler is good :), then the method will be fully inlined into the |
|
|
2245 | thunking function, making it as fast as a direct C callback. |
|
|
2246 | .Sp |
|
|
2247 | Example: simple class declaration and watcher initialisation |
|
|
2248 | .Sp |
|
|
2249 | .Vb 4 |
|
|
2250 | \& struct myclass |
|
|
2251 | \& { |
|
|
2252 | \& void io_cb (ev::io &w, int revents) { } |
|
|
2253 | \& } |
|
|
2254 | .Ve |
|
|
2255 | .Sp |
|
|
2256 | .Vb 3 |
|
|
2257 | \& myclass obj; |
|
|
2258 | \& ev::io iow; |
|
|
2259 | \& iow.set <myclass, &myclass::io_cb> (&obj); |
|
|
2260 | .Ve |
|
|
2261 | .IP "w\->set<function> (void *data = 0)" 4 |
|
|
2262 | .IX Item "w->set<function> (void *data = 0)" |
|
|
2263 | Also sets a callback, but uses a static method or plain function as |
|
|
2264 | callback. The optional \f(CW\*(C`data\*(C'\fR argument will be stored in the watcher's |
|
|
2265 | \&\f(CW\*(C`data\*(C'\fR member and is free for you to use. |
|
|
2266 | .Sp |
|
|
2267 | The prototype of the \f(CW\*(C`function\*(C'\fR must be \f(CW\*(C`void (*)(ev::TYPE &w, int)\*(C'\fR. |
|
|
2268 | .Sp |
|
|
2269 | See the method\-\f(CW\*(C`set\*(C'\fR above for more details. |
|
|
2270 | .Sp |
|
|
2271 | Example: |
|
|
2272 | .Sp |
|
|
2273 | .Vb 2 |
|
|
2274 | \& static void io_cb (ev::io &w, int revents) { } |
|
|
2275 | \& iow.set <io_cb> (); |
|
|
2276 | .Ve |
1937 | .IP "w\->set (struct ev_loop *)" 4 |
2277 | .IP "w\->set (struct ev_loop *)" 4 |
1938 | .IX Item "w->set (struct ev_loop *)" |
2278 | .IX Item "w->set (struct ev_loop *)" |
1939 | Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only |
2279 | Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only |
1940 | do this when the watcher is inactive (and not pending either). |
2280 | do this when the watcher is inactive (and not pending either). |
1941 | .IP "w\->set ([args])" 4 |
2281 | .IP "w\->set ([args])" 4 |
1942 | .IX Item "w->set ([args])" |
2282 | .IX Item "w->set ([args])" |
1943 | Basically the same as \f(CW\*(C`ev_TYPE_set\*(C'\fR, with the same args. Must be |
2283 | Basically the same as \f(CW\*(C`ev_TYPE_set\*(C'\fR, with the same args. Must be |
1944 | called at least once. Unlike the C counterpart, an active watcher gets |
2284 | called at least once. Unlike the C counterpart, an active watcher gets |
1945 | automatically stopped and restarted. |
2285 | automatically stopped and restarted when reconfiguring it with this |
|
|
2286 | method. |
1946 | .IP "w\->start ()" 4 |
2287 | .IP "w\->start ()" 4 |
1947 | .IX Item "w->start ()" |
2288 | .IX Item "w->start ()" |
1948 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument as the |
2289 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument, as the |
1949 | constructor already takes the loop. |
2290 | constructor already stores the event loop. |
1950 | .IP "w\->stop ()" 4 |
2291 | .IP "w\->stop ()" 4 |
1951 | .IX Item "w->stop ()" |
2292 | .IX Item "w->stop ()" |
1952 | Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument. |
2293 | Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument. |
1953 | .ie n .IP "w\->again () ""ev::timer""\fR, \f(CW""ev::periodic"" only" 4 |
2294 | .ie n .IP "w\->again () (""ev::timer""\fR, \f(CW""ev::periodic"" only)" 4 |
1954 | .el .IP "w\->again () \f(CWev::timer\fR, \f(CWev::periodic\fR only" 4 |
2295 | .el .IP "w\->again () (\f(CWev::timer\fR, \f(CWev::periodic\fR only)" 4 |
1955 | .IX Item "w->again () ev::timer, ev::periodic only" |
2296 | .IX Item "w->again () (ev::timer, ev::periodic only)" |
1956 | For \f(CW\*(C`ev::timer\*(C'\fR and \f(CW\*(C`ev::periodic\*(C'\fR, this invokes the corresponding |
2297 | For \f(CW\*(C`ev::timer\*(C'\fR and \f(CW\*(C`ev::periodic\*(C'\fR, this invokes the corresponding |
1957 | \&\f(CW\*(C`ev_TYPE_again\*(C'\fR function. |
2298 | \&\f(CW\*(C`ev_TYPE_again\*(C'\fR function. |
1958 | .ie n .IP "w\->sweep () ""ev::embed"" only" 4 |
2299 | .ie n .IP "w\->sweep () (""ev::embed"" only)" 4 |
1959 | .el .IP "w\->sweep () \f(CWev::embed\fR only" 4 |
2300 | .el .IP "w\->sweep () (\f(CWev::embed\fR only)" 4 |
1960 | .IX Item "w->sweep () ev::embed only" |
2301 | .IX Item "w->sweep () (ev::embed only)" |
1961 | Invokes \f(CW\*(C`ev_embed_sweep\*(C'\fR. |
2302 | Invokes \f(CW\*(C`ev_embed_sweep\*(C'\fR. |
1962 | .ie n .IP "w\->update () ""ev::stat"" only" 4 |
2303 | .ie n .IP "w\->update () (""ev::stat"" only)" 4 |
1963 | .el .IP "w\->update () \f(CWev::stat\fR only" 4 |
2304 | .el .IP "w\->update () (\f(CWev::stat\fR only)" 4 |
1964 | .IX Item "w->update () ev::stat only" |
2305 | .IX Item "w->update () (ev::stat only)" |
1965 | Invokes \f(CW\*(C`ev_stat_stat\*(C'\fR. |
2306 | Invokes \f(CW\*(C`ev_stat_stat\*(C'\fR. |
1966 | .RE |
2307 | .RE |
1967 | .RS 4 |
2308 | .RS 4 |
1968 | .RE |
2309 | .RE |
1969 | .PP |
2310 | .PP |
… | |
… | |
1980 | .Vb 2 |
2321 | .Vb 2 |
1981 | \& myclass (); |
2322 | \& myclass (); |
1982 | \& } |
2323 | \& } |
1983 | .Ve |
2324 | .Ve |
1984 | .PP |
2325 | .PP |
1985 | .Vb 6 |
2326 | .Vb 4 |
1986 | \& myclass::myclass (int fd) |
2327 | \& myclass::myclass (int fd) |
1987 | \& : io (this, &myclass::io_cb), |
|
|
1988 | \& idle (this, &myclass::idle_cb) |
|
|
1989 | \& { |
2328 | \& { |
|
|
2329 | \& io .set <myclass, &myclass::io_cb > (this); |
|
|
2330 | \& idle.set <myclass, &myclass::idle_cb> (this); |
|
|
2331 | .Ve |
|
|
2332 | .PP |
|
|
2333 | .Vb 2 |
1990 | \& io.start (fd, ev::READ); |
2334 | \& io.start (fd, ev::READ); |
1991 | \& } |
2335 | \& } |
1992 | .Ve |
2336 | .Ve |
1993 | .SH "MACRO MAGIC" |
2337 | .SH "MACRO MAGIC" |
1994 | .IX Header "MACRO MAGIC" |
2338 | .IX Header "MACRO MAGIC" |
1995 | Libev can be compiled with a variety of options, the most fundemantal is |
2339 | Libev can be compiled with a variety of options, the most fundamantal |
1996 | \&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines whether (most) functions and |
2340 | of which is \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines whether (most) |
1997 | callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument. |
2341 | functions and callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument. |
1998 | .PP |
2342 | .PP |
1999 | To make it easier to write programs that cope with either variant, the |
2343 | To make it easier to write programs that cope with either variant, the |
2000 | following macros are defined: |
2344 | following macros are defined: |
2001 | .ie n .IP """EV_A""\fR, \f(CW""EV_A_""" 4 |
2345 | .ie n .IP """EV_A""\fR, \f(CW""EV_A_""" 4 |
2002 | .el .IP "\f(CWEV_A\fR, \f(CWEV_A_\fR" 4 |
2346 | .el .IP "\f(CWEV_A\fR, \f(CWEV_A_\fR" 4 |
… | |
… | |
2061 | Libev can (and often is) directly embedded into host |
2405 | Libev can (and often is) directly embedded into host |
2062 | applications. Examples of applications that embed it include the Deliantra |
2406 | applications. Examples of applications that embed it include the Deliantra |
2063 | Game Server, the \s-1EV\s0 perl module, the \s-1GNU\s0 Virtual Private Ethernet (gvpe) |
2407 | Game Server, the \s-1EV\s0 perl module, the \s-1GNU\s0 Virtual Private Ethernet (gvpe) |
2064 | and rxvt\-unicode. |
2408 | and rxvt\-unicode. |
2065 | .PP |
2409 | .PP |
2066 | The goal is to enable you to just copy the neecssary files into your |
2410 | The goal is to enable you to just copy the necessary files into your |
2067 | source directory without having to change even a single line in them, so |
2411 | source directory without having to change even a single line in them, so |
2068 | you can easily upgrade by simply copying (or having a checked-out copy of |
2412 | you can easily upgrade by simply copying (or having a checked-out copy of |
2069 | libev somewhere in your source tree). |
2413 | libev somewhere in your source tree). |
2070 | .Sh "\s-1FILESETS\s0" |
2414 | .Sh "\s-1FILESETS\s0" |
2071 | .IX Subsection "FILESETS" |
2415 | .IX Subsection "FILESETS" |
… | |
… | |
2176 | .IX Item "EV_USE_MONOTONIC" |
2520 | .IX Item "EV_USE_MONOTONIC" |
2177 | If defined to be \f(CW1\fR, libev will try to detect the availability of the |
2521 | If defined to be \f(CW1\fR, libev will try to detect the availability of the |
2178 | monotonic clock option at both compiletime and runtime. Otherwise no use |
2522 | monotonic clock option at both compiletime and runtime. Otherwise no use |
2179 | of the monotonic clock option will be attempted. If you enable this, you |
2523 | of the monotonic clock option will be attempted. If you enable this, you |
2180 | usually have to link against librt or something similar. Enabling it when |
2524 | usually have to link against librt or something similar. Enabling it when |
2181 | the functionality isn't available is safe, though, althoguh you have |
2525 | the functionality isn't available is safe, though, although you have |
2182 | to make sure you link against any libraries where the \f(CW\*(C`clock_gettime\*(C'\fR |
2526 | to make sure you link against any libraries where the \f(CW\*(C`clock_gettime\*(C'\fR |
2183 | function is hiding in (often \fI\-lrt\fR). |
2527 | function is hiding in (often \fI\-lrt\fR). |
2184 | .IP "\s-1EV_USE_REALTIME\s0" 4 |
2528 | .IP "\s-1EV_USE_REALTIME\s0" 4 |
2185 | .IX Item "EV_USE_REALTIME" |
2529 | .IX Item "EV_USE_REALTIME" |
2186 | If defined to be \f(CW1\fR, libev will try to detect the availability of the |
2530 | If defined to be \f(CW1\fR, libev will try to detect the availability of the |
2187 | realtime clock option at compiletime (and assume its availability at |
2531 | realtime clock option at compiletime (and assume its availability at |
2188 | runtime if successful). Otherwise no use of the realtime clock option will |
2532 | runtime if successful). Otherwise no use of the realtime clock option will |
2189 | be attempted. This effectively replaces \f(CW\*(C`gettimeofday\*(C'\fR by \f(CW\*(C`clock_get |
2533 | be attempted. This effectively replaces \f(CW\*(C`gettimeofday\*(C'\fR by \f(CW\*(C`clock_get |
2190 | (CLOCK_REALTIME, ...)\*(C'\fR and will not normally affect correctness. See tzhe note about libraries |
2534 | (CLOCK_REALTIME, ...)\*(C'\fR and will not normally affect correctness. See the |
2191 | in the description of \f(CW\*(C`EV_USE_MONOTONIC\*(C'\fR, though. |
2535 | note about libraries in the description of \f(CW\*(C`EV_USE_MONOTONIC\*(C'\fR, though. |
|
|
2536 | .IP "\s-1EV_USE_NANOSLEEP\s0" 4 |
|
|
2537 | .IX Item "EV_USE_NANOSLEEP" |
|
|
2538 | If defined to be \f(CW1\fR, libev will assume that \f(CW\*(C`nanosleep ()\*(C'\fR is available |
|
|
2539 | and will use it for delays. Otherwise it will use \f(CW\*(C`select ()\*(C'\fR. |
2192 | .IP "\s-1EV_USE_SELECT\s0" 4 |
2540 | .IP "\s-1EV_USE_SELECT\s0" 4 |
2193 | .IX Item "EV_USE_SELECT" |
2541 | .IX Item "EV_USE_SELECT" |
2194 | If undefined or defined to be \f(CW1\fR, libev will compile in support for the |
2542 | If undefined or defined to be \f(CW1\fR, libev will compile in support for the |
2195 | \&\f(CW\*(C`select\*(C'\fR(2) backend. No attempt at autodetection will be done: if no |
2543 | \&\f(CW\*(C`select\*(C'\fR(2) backend. No attempt at autodetection will be done: if no |
2196 | other method takes over, select will be it. Otherwise the select backend |
2544 | other method takes over, select will be it. Otherwise the select backend |
… | |
… | |
2274 | If undefined or defined to \f(CW1\fR, then all event-loop-specific functions |
2622 | If undefined or defined to \f(CW1\fR, then all event-loop-specific functions |
2275 | will have the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument, and you can create |
2623 | will have the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument, and you can create |
2276 | additional independent event loops. Otherwise there will be no support |
2624 | additional independent event loops. Otherwise there will be no support |
2277 | for multiple event loops and there is no first event loop pointer |
2625 | for multiple event loops and there is no first event loop pointer |
2278 | argument. Instead, all functions act on the single default loop. |
2626 | argument. Instead, all functions act on the single default loop. |
|
|
2627 | .IP "\s-1EV_MINPRI\s0" 4 |
|
|
2628 | .IX Item "EV_MINPRI" |
|
|
2629 | .PD 0 |
|
|
2630 | .IP "\s-1EV_MAXPRI\s0" 4 |
|
|
2631 | .IX Item "EV_MAXPRI" |
|
|
2632 | .PD |
|
|
2633 | The range of allowed priorities. \f(CW\*(C`EV_MINPRI\*(C'\fR must be smaller or equal to |
|
|
2634 | \&\f(CW\*(C`EV_MAXPRI\*(C'\fR, but otherwise there are no non-obvious limitations. You can |
|
|
2635 | provide for more priorities by overriding those symbols (usually defined |
|
|
2636 | to be \f(CW\*(C`\-2\*(C'\fR and \f(CW2\fR, respectively). |
|
|
2637 | .Sp |
|
|
2638 | When doing priority-based operations, libev usually has to linearly search |
|
|
2639 | all the priorities, so having many of them (hundreds) uses a lot of space |
|
|
2640 | and time, so using the defaults of five priorities (\-2 .. +2) is usually |
|
|
2641 | fine. |
|
|
2642 | .Sp |
|
|
2643 | If your embedding app does not need any priorities, defining these both to |
|
|
2644 | \&\f(CW0\fR will save some memory and cpu. |
2279 | .IP "\s-1EV_PERIODIC_ENABLE\s0" 4 |
2645 | .IP "\s-1EV_PERIODIC_ENABLE\s0" 4 |
2280 | .IX Item "EV_PERIODIC_ENABLE" |
2646 | .IX Item "EV_PERIODIC_ENABLE" |
2281 | If undefined or defined to be \f(CW1\fR, then periodic timers are supported. If |
2647 | If undefined or defined to be \f(CW1\fR, then periodic timers are supported. If |
2282 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
2648 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
2283 | code. |
2649 | code. |
… | |
… | |
2338 | .IP "ev_set_cb (ev, cb)" 4 |
2704 | .IP "ev_set_cb (ev, cb)" 4 |
2339 | .IX Item "ev_set_cb (ev, cb)" |
2705 | .IX Item "ev_set_cb (ev, cb)" |
2340 | .PD |
2706 | .PD |
2341 | Can be used to change the callback member declaration in each watcher, |
2707 | Can be used to change the callback member declaration in each watcher, |
2342 | and the way callbacks are invoked and set. Must expand to a struct member |
2708 | and the way callbacks are invoked and set. Must expand to a struct member |
2343 | definition and a statement, respectively. See the \fIev.v\fR header file for |
2709 | definition and a statement, respectively. See the \fIev.h\fR header file for |
2344 | their default definitions. One possible use for overriding these is to |
2710 | their default definitions. One possible use for overriding these is to |
2345 | avoid the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument in all cases, or to use |
2711 | avoid the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument in all cases, or to use |
2346 | method calls instead of plain function calls in \*(C+. |
2712 | method calls instead of plain function calls in \*(C+. |
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|
2713 | .Sh "\s-1EXPORTED\s0 \s-1API\s0 \s-1SYMBOLS\s0" |
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2714 | .IX Subsection "EXPORTED API SYMBOLS" |
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|
2715 | If you need to re-export the \s-1API\s0 (e.g. via a dll) and you need a list of |
|
|
2716 | exported symbols, you can use the provided \fISymbol.*\fR files which list |
|
|
2717 | all public symbols, one per line: |
|
|
2718 | .Sp |
|
|
2719 | .Vb 2 |
|
|
2720 | \& Symbols.ev for libev proper |
|
|
2721 | \& Symbols.event for the libevent emulation |
|
|
2722 | .Ve |
|
|
2723 | .Sp |
|
|
2724 | This can also be used to rename all public symbols to avoid clashes with |
|
|
2725 | multiple versions of libev linked together (which is obviously bad in |
|
|
2726 | itself, but sometimes it is inconvinient to avoid this). |
|
|
2727 | .Sp |
|
|
2728 | A sed command like this will create wrapper \f(CW\*(C`#define\*(C'\fR's that you need to |
|
|
2729 | include before including \fIev.h\fR: |
|
|
2730 | .Sp |
|
|
2731 | .Vb 1 |
|
|
2732 | \& <Symbols.ev sed -e "s/.*/#define & myprefix_&/" >wrap.h |
|
|
2733 | .Ve |
|
|
2734 | .Sp |
|
|
2735 | This would create a file \fIwrap.h\fR which essentially looks like this: |
|
|
2736 | .Sp |
|
|
2737 | .Vb 4 |
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|
2738 | \& #define ev_backend myprefix_ev_backend |
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|
2739 | \& #define ev_check_start myprefix_ev_check_start |
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|
2740 | \& #define ev_check_stop myprefix_ev_check_stop |
|
|
2741 | \& ... |
|
|
2742 | .Ve |
2347 | .Sh "\s-1EXAMPLES\s0" |
2743 | .Sh "\s-1EXAMPLES\s0" |
2348 | .IX Subsection "EXAMPLES" |
2744 | .IX Subsection "EXAMPLES" |
2349 | For a real-world example of a program the includes libev |
2745 | For a real-world example of a program the includes libev |
2350 | verbatim, you can have a look at the \s-1EV\s0 perl module |
2746 | verbatim, you can have a look at the \s-1EV\s0 perl module |
2351 | (<http://software.schmorp.de/pkg/EV.html>). It has the libev files in |
2747 | (<http://software.schmorp.de/pkg/EV.html>). It has the libev files in |
… | |
… | |
2382 | .SH "COMPLEXITIES" |
2778 | .SH "COMPLEXITIES" |
2383 | .IX Header "COMPLEXITIES" |
2779 | .IX Header "COMPLEXITIES" |
2384 | In this section the complexities of (many of) the algorithms used inside |
2780 | In this section the complexities of (many of) the algorithms used inside |
2385 | libev will be explained. For complexity discussions about backends see the |
2781 | libev will be explained. For complexity discussions about backends see the |
2386 | documentation for \f(CW\*(C`ev_default_init\*(C'\fR. |
2782 | documentation for \f(CW\*(C`ev_default_init\*(C'\fR. |
|
|
2783 | .Sp |
|
|
2784 | All of the following are about amortised time: If an array needs to be |
|
|
2785 | extended, libev needs to realloc and move the whole array, but this |
|
|
2786 | happens asymptotically never with higher number of elements, so O(1) might |
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|
2787 | mean it might do a lengthy realloc operation in rare cases, but on average |
|
|
2788 | it is much faster and asymptotically approaches constant time. |
2387 | .RS 4 |
2789 | .RS 4 |
2388 | .IP "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" 4 |
2790 | .IP "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" 4 |
2389 | .IX Item "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" |
2791 | .IX Item "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" |
2390 | .PD 0 |
2792 | This means that, when you have a watcher that triggers in one hour and |
|
|
2793 | there are 100 watchers that would trigger before that then inserting will |
|
|
2794 | have to skip those 100 watchers. |
2391 | .IP "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" 4 |
2795 | .IP "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" 4 |
2392 | .IX Item "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" |
2796 | .IX Item "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" |
|
|
2797 | That means that for changing a timer costs less than removing/adding them |
|
|
2798 | as only the relative motion in the event queue has to be paid for. |
2393 | .IP "Starting io/check/prepare/idle/signal/child watchers: O(1)" 4 |
2799 | .IP "Starting io/check/prepare/idle/signal/child watchers: O(1)" 4 |
2394 | .IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)" |
2800 | .IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)" |
2395 | .IP "Stopping check/prepare/idle watchers: O(1)" 4 |
2801 | These just add the watcher into an array or at the head of a list. |
2396 | .IX Item "Stopping check/prepare/idle watchers: O(1)" |
2802 | =item Stopping check/prepare/idle watchers: O(1) |
2397 | .IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % \s-1EV_PID_HASHSIZE\s0))" 4 |
2803 | .IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % \s-1EV_PID_HASHSIZE\s0))" 4 |
2398 | .IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))" |
2804 | .IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))" |
|
|
2805 | These watchers are stored in lists then need to be walked to find the |
|
|
2806 | correct watcher to remove. The lists are usually short (you don't usually |
|
|
2807 | have many watchers waiting for the same fd or signal). |
2399 | .IP "Finding the next timer per loop iteration: O(1)" 4 |
2808 | .IP "Finding the next timer per loop iteration: O(1)" 4 |
2400 | .IX Item "Finding the next timer per loop iteration: O(1)" |
2809 | .IX Item "Finding the next timer per loop iteration: O(1)" |
|
|
2810 | .PD 0 |
2401 | .IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4 |
2811 | .IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4 |
2402 | .IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" |
2812 | .IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" |
|
|
2813 | .PD |
|
|
2814 | A change means an I/O watcher gets started or stopped, which requires |
|
|
2815 | libev to recalculate its status (and possibly tell the kernel). |
2403 | .IP "Activating one watcher: O(1)" 4 |
2816 | .IP "Activating one watcher: O(1)" 4 |
2404 | .IX Item "Activating one watcher: O(1)" |
2817 | .IX Item "Activating one watcher: O(1)" |
|
|
2818 | .PD 0 |
|
|
2819 | .IP "Priority handling: O(number_of_priorities)" 4 |
|
|
2820 | .IX Item "Priority handling: O(number_of_priorities)" |
|
|
2821 | .PD |
|
|
2822 | Priorities are implemented by allocating some space for each |
|
|
2823 | priority. When doing priority-based operations, libev usually has to |
|
|
2824 | linearly search all the priorities. |
2405 | .RE |
2825 | .RE |
2406 | .RS 4 |
2826 | .RS 4 |
2407 | .PD |
|
|
2408 | .SH "AUTHOR" |
2827 | .SH "AUTHOR" |
2409 | .IX Header "AUTHOR" |
2828 | .IX Header "AUTHOR" |
2410 | Marc Lehmann <libev@schmorp.de>. |
2829 | Marc Lehmann <libev@schmorp.de>. |