… | |
… | |
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 "2007-12-12" "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 |
… | |
… | |
201 | The newest version of this document is also available as a html-formatted |
201 | The newest version of this document is also available as a html-formatted |
202 | web page you might find easier to navigate when reading it for the first |
202 | web page you might find easier to navigate when reading it for the first |
203 | time: <http://cvs.schmorp.de/libev/ev.html>. |
203 | time: <http://cvs.schmorp.de/libev/ev.html>. |
204 | .PP |
204 | .PP |
205 | Libev is an event loop: you register interest in certain events (such as a |
205 | Libev is an event loop: you register interest in certain events (such as a |
206 | file descriptor being readable or a timeout occuring), and it will manage |
206 | file descriptor being readable or a timeout occurring), and it will manage |
207 | these event sources and provide your program with events. |
207 | these event sources and provide your program with events. |
208 | .PP |
208 | .PP |
209 | To do this, it must take more or less complete control over your process |
209 | To do this, it must take more or less complete control over your process |
210 | (or thread) by executing the \fIevent loop\fR handler, and will then |
210 | (or thread) by executing the \fIevent loop\fR handler, and will then |
211 | communicate events via a callback mechanism. |
211 | communicate events via a callback mechanism. |
… | |
… | |
243 | Libev represents time as a single floating point number, representing the |
243 | Libev represents time as a single floating point number, representing the |
244 | (fractional) number of seconds since the (\s-1POSIX\s0) epoch (somewhere near |
244 | (fractional) number of seconds since the (\s-1POSIX\s0) epoch (somewhere near |
245 | the beginning of 1970, details are complicated, don't ask). This type is |
245 | the beginning of 1970, details are complicated, don't ask). This type is |
246 | called \f(CW\*(C`ev_tstamp\*(C'\fR, which is what you should use too. It usually aliases |
246 | called \f(CW\*(C`ev_tstamp\*(C'\fR, which is what you should use too. It usually aliases |
247 | to the \f(CW\*(C`double\*(C'\fR type in C, and when you need to do any calculations on |
247 | to the \f(CW\*(C`double\*(C'\fR type in C, and when you need to do any calculations on |
248 | it, you should treat it as such. |
248 | it, you should treat it as some floatingpoint value. Unlike the name |
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249 | component \f(CW\*(C`stamp\*(C'\fR might indicate, it is also used for time differences |
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250 | throughout libev. |
249 | .SH "GLOBAL FUNCTIONS" |
251 | .SH "GLOBAL FUNCTIONS" |
250 | .IX Header "GLOBAL FUNCTIONS" |
252 | .IX Header "GLOBAL FUNCTIONS" |
251 | These functions can be called anytime, even before initialising the |
253 | These functions can be called anytime, even before initialising the |
252 | library in any way. |
254 | library in any way. |
253 | .IP "ev_tstamp ev_time ()" 4 |
255 | .IP "ev_tstamp ev_time ()" 4 |
254 | .IX Item "ev_tstamp ev_time ()" |
256 | .IX Item "ev_tstamp ev_time ()" |
255 | Returns the current time as libev would use it. Please note that the |
257 | Returns the current time as libev would use it. Please note that the |
256 | \&\f(CW\*(C`ev_now\*(C'\fR function is usually faster and also often returns the timestamp |
258 | \&\f(CW\*(C`ev_now\*(C'\fR function is usually faster and also often returns the timestamp |
257 | you actually want to know. |
259 | you actually want to know. |
|
|
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. |
258 | .IP "int ev_version_major ()" 4 |
265 | .IP "int ev_version_major ()" 4 |
259 | .IX Item "int ev_version_major ()" |
266 | .IX Item "int ev_version_major ()" |
260 | .PD 0 |
267 | .PD 0 |
261 | .IP "int ev_version_minor ()" 4 |
268 | .IP "int ev_version_minor ()" 4 |
262 | .IX Item "int ev_version_minor ()" |
269 | .IX Item "int ev_version_minor ()" |
… | |
… | |
457 | 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). |
458 | .ie n .IP """EVBACKEND_EPOLL"" (value 4, Linux)" 4 |
465 | .ie n .IP """EVBACKEND_EPOLL"" (value 4, Linux)" 4 |
459 | .el .IP "\f(CWEVBACKEND_EPOLL\fR (value 4, Linux)" 4 |
466 | .el .IP "\f(CWEVBACKEND_EPOLL\fR (value 4, Linux)" 4 |
460 | .IX Item "EVBACKEND_EPOLL (value 4, Linux)" |
467 | .IX Item "EVBACKEND_EPOLL (value 4, Linux)" |
461 | 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, |
462 | but it scales phenomenally better. While poll and select usually scale like |
469 | but it scales phenomenally better. While poll and select usually scale |
463 | 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), |
464 | 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: |
465 | .Sp |
475 | .Sp |
466 | 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 |
467 | 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 |
468 | (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 |
469 | 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 |
470 | well if you register events for both fds. |
480 | very well if you register events for both fds. |
471 | .Sp |
481 | .Sp |
472 | Please note that epoll sometimes generates spurious notifications, so you |
482 | Please note that epoll sometimes generates spurious notifications, so you |
473 | 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 |
474 | (or space) is available. |
484 | (or space) is available. |
475 | .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 |
476 | .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 |
477 | .IX Item "EVBACKEND_KQUEUE (value 8, most BSD clones)" |
487 | .IX Item "EVBACKEND_KQUEUE (value 8, most BSD clones)" |
478 | 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 |
479 | 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 |
480 | 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 |
481 | 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" |
482 | 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 |
483 | \&\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) |
|
|
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. |
484 | .Sp |
499 | .Sp |
485 | 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 |
486 | 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 |
487 | 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 |
488 | 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 |
489 | 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. |
490 | .ie n .IP """EVBACKEND_DEVPOLL"" (value 16, Solaris 8)" 4 |
506 | .ie n .IP """EVBACKEND_DEVPOLL"" (value 16, Solaris 8)" 4 |
491 | .el .IP "\f(CWEVBACKEND_DEVPOLL\fR (value 16, Solaris 8)" 4 |
507 | .el .IP "\f(CWEVBACKEND_DEVPOLL\fR (value 16, Solaris 8)" 4 |
492 | .IX Item "EVBACKEND_DEVPOLL (value 16, Solaris 8)" |
508 | .IX Item "EVBACKEND_DEVPOLL (value 16, Solaris 8)" |
493 | This is not implemented yet (and might never be). |
509 | This is not implemented yet (and might never be). |
494 | .ie n .IP """EVBACKEND_PORT"" (value 32, Solaris 10)" 4 |
510 | .ie n .IP """EVBACKEND_PORT"" (value 32, Solaris 10)" 4 |
495 | .el .IP "\f(CWEVBACKEND_PORT\fR (value 32, Solaris 10)" 4 |
511 | .el .IP "\f(CWEVBACKEND_PORT\fR (value 32, Solaris 10)" 4 |
496 | .IX Item "EVBACKEND_PORT (value 32, Solaris 10)" |
512 | .IX Item "EVBACKEND_PORT (value 32, Solaris 10)" |
497 | 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, |
498 | 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)). |
499 | .Sp |
515 | .Sp |
500 | 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 |
501 | 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 |
502 | blocking when no data (or space) is available. |
518 | blocking when no data (or space) is available. |
503 | .ie n .IP """EVBACKEND_ALL""" 4 |
519 | .ie n .IP """EVBACKEND_ALL""" 4 |
504 | .el .IP "\f(CWEVBACKEND_ALL\fR" 4 |
520 | .el .IP "\f(CWEVBACKEND_ALL\fR" 4 |
505 | .IX Item "EVBACKEND_ALL" |
521 | .IX Item "EVBACKEND_ALL" |
… | |
… | |
555 | Destroys the default loop again (frees all memory and kernel state |
571 | Destroys the default loop again (frees all memory and kernel state |
556 | 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 |
557 | 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 |
558 | responsibility to either stop all watchers cleanly yoursef \fIbefore\fR |
574 | responsibility to either stop all watchers cleanly yoursef \fIbefore\fR |
559 | 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 |
560 | 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 |
561 | 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). |
562 | .IP "ev_loop_destroy (loop)" 4 |
587 | .IP "ev_loop_destroy (loop)" 4 |
563 | .IX Item "ev_loop_destroy (loop)" |
588 | .IX Item "ev_loop_destroy (loop)" |
564 | 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 |
565 | earlier call to \f(CW\*(C`ev_loop_new\*(C'\fR. |
590 | earlier call to \f(CW\*(C`ev_loop_new\*(C'\fR. |
566 | .IP "ev_default_fork ()" 4 |
591 | .IP "ev_default_fork ()" 4 |
… | |
… | |
607 | .IX Item "ev_tstamp ev_now (loop)" |
632 | .IX Item "ev_tstamp ev_now (loop)" |
608 | 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 |
609 | received events and started processing them. This timestamp does not |
634 | received events and started processing them. This timestamp does not |
610 | 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 |
611 | 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 |
612 | event occuring (or more correctly, libev finding out about it). |
637 | event occurring (or more correctly, libev finding out about it). |
613 | .IP "ev_loop (loop, int flags)" 4 |
638 | .IP "ev_loop (loop, int flags)" 4 |
614 | .IX Item "ev_loop (loop, int flags)" |
639 | .IX Item "ev_loop (loop, int flags)" |
615 | 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 |
616 | 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 |
617 | events. |
642 | events. |
… | |
… | |
707 | .Sp |
732 | .Sp |
708 | .Vb 2 |
733 | .Vb 2 |
709 | \& ev_ref (loop); |
734 | \& ev_ref (loop); |
710 | \& ev_signal_stop (loop, &exitsig); |
735 | \& ev_signal_stop (loop, &exitsig); |
711 | .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. |
712 | .SH "ANATOMY OF A WATCHER" |
774 | .SH "ANATOMY OF A WATCHER" |
713 | .IX Header "ANATOMY OF A WATCHER" |
775 | .IX Header "ANATOMY OF A WATCHER" |
714 | 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 |
715 | 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 |
716 | 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: |
… | |
… | |
1069 | its own, so its quite safe to use). |
1131 | its own, so its quite safe to use). |
1070 | .PP |
1132 | .PP |
1071 | \fIThe special problem of disappearing file descriptors\fR |
1133 | \fIThe special problem of disappearing file descriptors\fR |
1072 | .IX Subsection "The special problem of disappearing file descriptors" |
1134 | .IX Subsection "The special problem of disappearing file descriptors" |
1073 | .PP |
1135 | .PP |
1074 | Some backends (e.g kqueue, epoll) need to be told about closing a file |
1136 | Some backends (e.g. kqueue, epoll) need to be told about closing a file |
1075 | descriptor (either by calling \f(CW\*(C`close\*(C'\fR explicitly or by any other means, |
1137 | descriptor (either by calling \f(CW\*(C`close\*(C'\fR explicitly or by any other means, |
1076 | such as \f(CW\*(C`dup\*(C'\fR). The reason is that you register interest in some file |
1138 | such as \f(CW\*(C`dup\*(C'\fR). The reason is that you register interest in some file |
1077 | descriptor, but when it goes away, the operating system will silently drop |
1139 | descriptor, but when it goes away, the operating system will silently drop |
1078 | this interest. If another file descriptor with the same number then is |
1140 | this interest. If another file descriptor with the same number then is |
1079 | registered with libev, there is no efficient way to see that this is, in |
1141 | registered with libev, there is no efficient way to see that this is, in |
… | |
… | |
1087 | descriptor even if the file descriptor number itself did not change. |
1149 | descriptor even if the file descriptor number itself did not change. |
1088 | .PP |
1150 | .PP |
1089 | This is how one would do it normally anyway, the important point is that |
1151 | This is how one would do it normally anyway, the important point is that |
1090 | the libev application should not optimise around libev but should leave |
1152 | the libev application should not optimise around libev but should leave |
1091 | optimisations to libev. |
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. |
1092 | .PP |
1178 | .PP |
1093 | \fIWatcher-Specific Functions\fR |
1179 | \fIWatcher-Specific Functions\fR |
1094 | .IX Subsection "Watcher-Specific Functions" |
1180 | .IX Subsection "Watcher-Specific Functions" |
1095 | .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 |
1096 | .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)" |
… | |
… | |
1379 | .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 |
1380 | .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]" |
1381 | 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 |
1382 | 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 |
1383 | 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. |
1384 | .PP |
1474 | .PP |
1385 | Example: Call a callback every hour, or, more precisely, whenever the |
1475 | Example: Call a callback every hour, or, more precisely, whenever the |
1386 | system clock is divisible by 3600. The callback invocation times have |
1476 | system clock is divisible by 3600. The callback invocation times have |
1387 | potentially a lot of jittering, but good long-term stability. |
1477 | potentially a lot of jittering, but good long-term stability. |
1388 | .PP |
1478 | .PP |
… | |
… | |
1697 | .PP |
1787 | .PP |
1698 | It is recommended to give \f(CW\*(C`ev_check\*(C'\fR watchers highest (\f(CW\*(C`EV_MAXPRI\*(C'\fR) |
1788 | It is recommended to give \f(CW\*(C`ev_check\*(C'\fR watchers highest (\f(CW\*(C`EV_MAXPRI\*(C'\fR) |
1699 | priority, to ensure that they are being run before any other watchers |
1789 | priority, to ensure that they are being run before any other watchers |
1700 | after the poll. Also, \f(CW\*(C`ev_check\*(C'\fR watchers (and \f(CW\*(C`ev_prepare\*(C'\fR watchers, |
1790 | after the poll. Also, \f(CW\*(C`ev_check\*(C'\fR watchers (and \f(CW\*(C`ev_prepare\*(C'\fR watchers, |
1701 | too) should not activate (\*(L"feed\*(R") events into libev. While libev fully |
1791 | too) should not activate (\*(L"feed\*(R") events into libev. While libev fully |
1702 | supports this, they will be called before other \f(CW\*(C`ev_check\*(C'\fR watchers did |
1792 | supports this, they will be called before other \f(CW\*(C`ev_check\*(C'\fR watchers |
1703 | their job. As \f(CW\*(C`ev_check\*(C'\fR watchers are often used to embed other event |
1793 | did their job. As \f(CW\*(C`ev_check\*(C'\fR watchers are often used to embed other |
1704 | loops those other event loops might be in an unusable state until their |
1794 | (non\-libev) event loops those other event loops might be in an unusable |
1705 | \&\f(CW\*(C`ev_check\*(C'\fR watcher ran (always remind yourself to coexist peacefully with |
1795 | state until their \f(CW\*(C`ev_check\*(C'\fR watcher ran (always remind yourself to |
1706 | others). |
1796 | coexist peacefully with others). |
1707 | .PP |
1797 | .PP |
1708 | \fIWatcher-Specific Functions and Data Members\fR |
1798 | \fIWatcher-Specific Functions and Data Members\fR |
1709 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1799 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1710 | .IP "ev_prepare_init (ev_prepare *, callback)" 4 |
1800 | .IP "ev_prepare_init (ev_prepare *, callback)" 4 |
1711 | .IX Item "ev_prepare_init (ev_prepare *, callback)" |
1801 | .IX Item "ev_prepare_init (ev_prepare *, callback)" |
… | |
… | |
1980 | .IP "ev_embed_sweep (loop, ev_embed *)" 4 |
2070 | .IP "ev_embed_sweep (loop, ev_embed *)" 4 |
1981 | .IX Item "ev_embed_sweep (loop, ev_embed *)" |
2071 | .IX Item "ev_embed_sweep (loop, ev_embed *)" |
1982 | 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 |
1983 | 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 |
1984 | apropriate way for embedded loops. |
2074 | apropriate way for embedded loops. |
1985 | .IP "struct ev_loop *loop [read\-only]" 4 |
2075 | .IP "struct ev_loop *other [read\-only]" 4 |
1986 | .IX Item "struct ev_loop *loop [read-only]" |
2076 | .IX Item "struct ev_loop *other [read-only]" |
1987 | The embedded event loop. |
2077 | The embedded event loop. |
1988 | .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" |
1989 | .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" |
1990 | .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" |
1991 | 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 |
… | |
… | |
2199 | 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 |
2200 | constructor already stores the event loop. |
2290 | constructor already stores the event loop. |
2201 | .IP "w\->stop ()" 4 |
2291 | .IP "w\->stop ()" 4 |
2202 | .IX Item "w->stop ()" |
2292 | .IX Item "w->stop ()" |
2203 | 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. |
2204 | .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 |
2205 | .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 |
2206 | .IX Item "w->again () ev::timer, ev::periodic only" |
2296 | .IX Item "w->again () (ev::timer, ev::periodic only)" |
2207 | 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 |
2208 | \&\f(CW\*(C`ev_TYPE_again\*(C'\fR function. |
2298 | \&\f(CW\*(C`ev_TYPE_again\*(C'\fR function. |
2209 | .ie n .IP "w\->sweep () ""ev::embed"" only" 4 |
2299 | .ie n .IP "w\->sweep () (""ev::embed"" only)" 4 |
2210 | .el .IP "w\->sweep () \f(CWev::embed\fR only" 4 |
2300 | .el .IP "w\->sweep () (\f(CWev::embed\fR only)" 4 |
2211 | .IX Item "w->sweep () ev::embed only" |
2301 | .IX Item "w->sweep () (ev::embed only)" |
2212 | Invokes \f(CW\*(C`ev_embed_sweep\*(C'\fR. |
2302 | Invokes \f(CW\*(C`ev_embed_sweep\*(C'\fR. |
2213 | .ie n .IP "w\->update () ""ev::stat"" only" 4 |
2303 | .ie n .IP "w\->update () (""ev::stat"" only)" 4 |
2214 | .el .IP "w\->update () \f(CWev::stat\fR only" 4 |
2304 | .el .IP "w\->update () (\f(CWev::stat\fR only)" 4 |
2215 | .IX Item "w->update () ev::stat only" |
2305 | .IX Item "w->update () (ev::stat only)" |
2216 | Invokes \f(CW\*(C`ev_stat_stat\*(C'\fR. |
2306 | Invokes \f(CW\*(C`ev_stat_stat\*(C'\fR. |
2217 | .RE |
2307 | .RE |
2218 | .RS 4 |
2308 | .RS 4 |
2219 | .RE |
2309 | .RE |
2220 | .PP |
2310 | .PP |
… | |
… | |
2244 | \& io.start (fd, ev::READ); |
2334 | \& io.start (fd, ev::READ); |
2245 | \& } |
2335 | \& } |
2246 | .Ve |
2336 | .Ve |
2247 | .SH "MACRO MAGIC" |
2337 | .SH "MACRO MAGIC" |
2248 | .IX Header "MACRO MAGIC" |
2338 | .IX Header "MACRO MAGIC" |
2249 | 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 |
2250 | \&\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) |
2251 | 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. |
2252 | .PP |
2342 | .PP |
2253 | 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 |
2254 | following macros are defined: |
2344 | following macros are defined: |
2255 | .ie n .IP """EV_A""\fR, \f(CW""EV_A_""" 4 |
2345 | .ie n .IP """EV_A""\fR, \f(CW""EV_A_""" 4 |
2256 | .el .IP "\f(CWEV_A\fR, \f(CWEV_A_\fR" 4 |
2346 | .el .IP "\f(CWEV_A\fR, \f(CWEV_A_\fR" 4 |
… | |
… | |
2315 | Libev can (and often is) directly embedded into host |
2405 | Libev can (and often is) directly embedded into host |
2316 | applications. Examples of applications that embed it include the Deliantra |
2406 | applications. Examples of applications that embed it include the Deliantra |
2317 | 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) |
2318 | and rxvt\-unicode. |
2408 | and rxvt\-unicode. |
2319 | .PP |
2409 | .PP |
2320 | 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 |
2321 | 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 |
2322 | 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 |
2323 | libev somewhere in your source tree). |
2413 | libev somewhere in your source tree). |
2324 | .Sh "\s-1FILESETS\s0" |
2414 | .Sh "\s-1FILESETS\s0" |
2325 | .IX Subsection "FILESETS" |
2415 | .IX Subsection "FILESETS" |
… | |
… | |
2430 | .IX Item "EV_USE_MONOTONIC" |
2520 | .IX Item "EV_USE_MONOTONIC" |
2431 | 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 |
2432 | monotonic clock option at both compiletime and runtime. Otherwise no use |
2522 | monotonic clock option at both compiletime and runtime. Otherwise no use |
2433 | 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 |
2434 | 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 |
2435 | the functionality isn't available is safe, though, althoguh you have |
2525 | the functionality isn't available is safe, though, although you have |
2436 | 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 |
2437 | function is hiding in (often \fI\-lrt\fR). |
2527 | function is hiding in (often \fI\-lrt\fR). |
2438 | .IP "\s-1EV_USE_REALTIME\s0" 4 |
2528 | .IP "\s-1EV_USE_REALTIME\s0" 4 |
2439 | .IX Item "EV_USE_REALTIME" |
2529 | .IX Item "EV_USE_REALTIME" |
2440 | 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 |
2441 | realtime clock option at compiletime (and assume its availability at |
2531 | realtime clock option at compiletime (and assume its availability at |
2442 | 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 |
2443 | 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 |
2444 | (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 |
2445 | 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. |
2446 | .IP "\s-1EV_USE_SELECT\s0" 4 |
2540 | .IP "\s-1EV_USE_SELECT\s0" 4 |
2447 | .IX Item "EV_USE_SELECT" |
2541 | .IX Item "EV_USE_SELECT" |
2448 | 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 |
2449 | \&\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 |
2450 | 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 |
… | |
… | |
2610 | .IP "ev_set_cb (ev, cb)" 4 |
2704 | .IP "ev_set_cb (ev, cb)" 4 |
2611 | .IX Item "ev_set_cb (ev, cb)" |
2705 | .IX Item "ev_set_cb (ev, cb)" |
2612 | .PD |
2706 | .PD |
2613 | 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, |
2614 | 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 |
2615 | 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 |
2616 | their default definitions. One possible use for overriding these is to |
2710 | their default definitions. One possible use for overriding these is to |
2617 | 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 |
2618 | method calls instead of plain function calls in \*(C+. |
2712 | method calls instead of plain function calls in \*(C+. |
|
|
2713 | .Sh "\s-1EXPORTED\s0 \s-1API\s0 \s-1SYMBOLS\s0" |
|
|
2714 | .IX Subsection "EXPORTED API SYMBOLS" |
|
|
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 |
|
|
2738 | \& #define ev_backend myprefix_ev_backend |
|
|
2739 | \& #define ev_check_start myprefix_ev_check_start |
|
|
2740 | \& #define ev_check_stop myprefix_ev_check_stop |
|
|
2741 | \& ... |
|
|
2742 | .Ve |
2619 | .Sh "\s-1EXAMPLES\s0" |
2743 | .Sh "\s-1EXAMPLES\s0" |
2620 | .IX Subsection "EXAMPLES" |
2744 | .IX Subsection "EXAMPLES" |
2621 | For a real-world example of a program the includes libev |
2745 | For a real-world example of a program the includes libev |
2622 | 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 |
2623 | (<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 |