… | |
… | |
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 "2007-12-21" "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 |
|
|
249 | component \f(CW\*(C`stamp\*(C'\fR might indicate, it is also used for time differences |
|
|
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 |
… | |
… | |
259 | .IX Item "int ev_version_major ()" |
261 | .IX Item "int ev_version_major ()" |
260 | .PD 0 |
262 | .PD 0 |
261 | .IP "int ev_version_minor ()" 4 |
263 | .IP "int ev_version_minor ()" 4 |
262 | .IX Item "int ev_version_minor ()" |
264 | .IX Item "int ev_version_minor ()" |
263 | .PD |
265 | .PD |
264 | You can find out the major and minor version numbers of the library |
266 | You can find out the major and minor \s-1ABI\s0 version numbers of the library |
265 | you linked against by calling the functions \f(CW\*(C`ev_version_major\*(C'\fR and |
267 | you linked against by calling the functions \f(CW\*(C`ev_version_major\*(C'\fR and |
266 | \&\f(CW\*(C`ev_version_minor\*(C'\fR. If you want, you can compare against the global |
268 | \&\f(CW\*(C`ev_version_minor\*(C'\fR. If you want, you can compare against the global |
267 | symbols \f(CW\*(C`EV_VERSION_MAJOR\*(C'\fR and \f(CW\*(C`EV_VERSION_MINOR\*(C'\fR, which specify the |
269 | symbols \f(CW\*(C`EV_VERSION_MAJOR\*(C'\fR and \f(CW\*(C`EV_VERSION_MINOR\*(C'\fR, which specify the |
268 | version of the library your program was compiled against. |
270 | version of the library your program was compiled against. |
269 | .Sp |
271 | .Sp |
|
|
272 | These version numbers refer to the \s-1ABI\s0 version of the library, not the |
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|
273 | release version. |
|
|
274 | .Sp |
270 | Usually, it's a good idea to terminate if the major versions mismatch, |
275 | Usually, it's a good idea to terminate if the major versions mismatch, |
271 | as this indicates an incompatible change. Minor versions are usually |
276 | as this indicates an incompatible change. Minor versions are usually |
272 | compatible to older versions, so a larger minor version alone is usually |
277 | compatible to older versions, so a larger minor version alone is usually |
273 | not a problem. |
278 | not a problem. |
274 | .Sp |
279 | .Sp |
275 | Example: Make sure we haven't accidentally been linked against the wrong |
280 | Example: Make sure we haven't accidentally been linked against the wrong |
276 | version. |
281 | version. |
… | |
… | |
454 | lot of inactive fds). It scales similarly to select, i.e. O(total_fds). |
459 | lot of inactive fds). It scales similarly to select, i.e. O(total_fds). |
455 | .ie n .IP """EVBACKEND_EPOLL"" (value 4, Linux)" 4 |
460 | .ie n .IP """EVBACKEND_EPOLL"" (value 4, Linux)" 4 |
456 | .el .IP "\f(CWEVBACKEND_EPOLL\fR (value 4, Linux)" 4 |
461 | .el .IP "\f(CWEVBACKEND_EPOLL\fR (value 4, Linux)" 4 |
457 | .IX Item "EVBACKEND_EPOLL (value 4, Linux)" |
462 | .IX Item "EVBACKEND_EPOLL (value 4, Linux)" |
458 | For few fds, this backend is a bit little slower than poll and select, |
463 | For few fds, this backend is a bit little slower than poll and select, |
459 | but it scales phenomenally better. While poll and select usually scale like |
464 | but it scales phenomenally better. While poll and select usually scale |
460 | O(total_fds) where n is the total number of fds (or the highest fd), epoll scales |
465 | like O(total_fds) where n is the total number of fds (or the highest fd), |
461 | either O(1) or O(active_fds). |
466 | epoll scales either O(1) or O(active_fds). The epoll design has a number |
|
|
467 | of shortcomings, such as silently dropping events in some hard-to-detect |
|
|
468 | cases and rewuiring a syscall per fd change, no fork support and bad |
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|
469 | support for dup: |
462 | .Sp |
470 | .Sp |
463 | While stopping and starting an I/O watcher in the same iteration will |
471 | While stopping, setting and starting an I/O watcher in the same iteration |
464 | result in some caching, there is still a syscall per such incident |
472 | will result in some caching, there is still a syscall per such incident |
465 | (because the fd could point to a different file description now), so its |
473 | (because the fd could point to a different file description now), so its |
466 | best to avoid that. Also, \fIdup()\fRed file descriptors might not work very |
474 | best to avoid that. Also, \f(CW\*(C`dup ()\*(C'\fR'ed file descriptors might not work |
467 | well if you register events for both fds. |
475 | very well if you register events for both fds. |
468 | .Sp |
476 | .Sp |
469 | Please note that epoll sometimes generates spurious notifications, so you |
477 | Please note that epoll sometimes generates spurious notifications, so you |
470 | need to use non-blocking I/O or other means to avoid blocking when no data |
478 | need to use non-blocking I/O or other means to avoid blocking when no data |
471 | (or space) is available. |
479 | (or space) is available. |
472 | .ie n .IP """EVBACKEND_KQUEUE"" (value 8, most \s-1BSD\s0 clones)" 4 |
480 | .ie n .IP """EVBACKEND_KQUEUE"" (value 8, most \s-1BSD\s0 clones)" 4 |
473 | .el .IP "\f(CWEVBACKEND_KQUEUE\fR (value 8, most \s-1BSD\s0 clones)" 4 |
481 | .el .IP "\f(CWEVBACKEND_KQUEUE\fR (value 8, most \s-1BSD\s0 clones)" 4 |
474 | .IX Item "EVBACKEND_KQUEUE (value 8, most BSD clones)" |
482 | .IX Item "EVBACKEND_KQUEUE (value 8, most BSD clones)" |
475 | Kqueue deserves special mention, as at the time of this writing, it |
483 | Kqueue deserves special mention, as at the time of this writing, it |
476 | was broken on all BSDs except NetBSD (usually it doesn't work with |
484 | was broken on \fIall\fR BSDs (usually it doesn't work with anything but |
477 | anything but sockets and pipes, except on Darwin, where of course its |
485 | sockets and pipes, except on Darwin, where of course it's completely |
|
|
486 | useless. On NetBSD, it seems to work for all the \s-1FD\s0 types I tested, so it |
478 | completely useless). For this reason its not being \*(L"autodetected\*(R" |
487 | is used by default there). For this reason it's not being \*(L"autodetected\*(R" |
479 | unless you explicitly specify it explicitly in the flags (i.e. using |
488 | unless you explicitly specify it explicitly in the flags (i.e. using |
480 | \&\f(CW\*(C`EVBACKEND_KQUEUE\*(C'\fR). |
489 | \&\f(CW\*(C`EVBACKEND_KQUEUE\*(C'\fR) or libev was compiled on a known-to-be-good (\-enough) |
|
|
490 | system like NetBSD. |
481 | .Sp |
491 | .Sp |
482 | It scales in the same way as the epoll backend, but the interface to the |
492 | It scales in the same way as the epoll backend, but the interface to the |
483 | kernel is more efficient (which says nothing about its actual speed, of |
493 | kernel is more efficient (which says nothing about its actual speed, |
484 | course). While starting and stopping an I/O watcher does not cause an |
494 | of course). While stopping, setting and starting an I/O watcher does |
485 | extra syscall as with epoll, it still adds up to four event changes per |
495 | never cause an extra syscall as with epoll, it still adds up to two event |
486 | incident, so its best to avoid that. |
496 | changes per incident, support for \f(CW\*(C`fork ()\*(C'\fR is very bad and it drops fds |
|
|
497 | silently in similarly hard-to-detetc cases. |
487 | .ie n .IP """EVBACKEND_DEVPOLL"" (value 16, Solaris 8)" 4 |
498 | .ie n .IP """EVBACKEND_DEVPOLL"" (value 16, Solaris 8)" 4 |
488 | .el .IP "\f(CWEVBACKEND_DEVPOLL\fR (value 16, Solaris 8)" 4 |
499 | .el .IP "\f(CWEVBACKEND_DEVPOLL\fR (value 16, Solaris 8)" 4 |
489 | .IX Item "EVBACKEND_DEVPOLL (value 16, Solaris 8)" |
500 | .IX Item "EVBACKEND_DEVPOLL (value 16, Solaris 8)" |
490 | This is not implemented yet (and might never be). |
501 | This is not implemented yet (and might never be). |
491 | .ie n .IP """EVBACKEND_PORT"" (value 32, Solaris 10)" 4 |
502 | .ie n .IP """EVBACKEND_PORT"" (value 32, Solaris 10)" 4 |
492 | .el .IP "\f(CWEVBACKEND_PORT\fR (value 32, Solaris 10)" 4 |
503 | .el .IP "\f(CWEVBACKEND_PORT\fR (value 32, Solaris 10)" 4 |
493 | .IX Item "EVBACKEND_PORT (value 32, Solaris 10)" |
504 | .IX Item "EVBACKEND_PORT (value 32, Solaris 10)" |
494 | This uses the Solaris 10 port mechanism. As with everything on Solaris, |
505 | This uses the Solaris 10 event port mechanism. As with everything on Solaris, |
495 | it's really slow, but it still scales very well (O(active_fds)). |
506 | it's really slow, but it still scales very well (O(active_fds)). |
496 | .Sp |
507 | .Sp |
497 | Please note that solaris ports can result in a lot of spurious |
508 | Please note that solaris event ports can deliver a lot of spurious |
498 | notifications, so you need to use non-blocking I/O or other means to avoid |
509 | notifications, so you need to use non-blocking I/O or other means to avoid |
499 | blocking when no data (or space) is available. |
510 | blocking when no data (or space) is available. |
500 | .ie n .IP """EVBACKEND_ALL""" 4 |
511 | .ie n .IP """EVBACKEND_ALL""" 4 |
501 | .el .IP "\f(CWEVBACKEND_ALL\fR" 4 |
512 | .el .IP "\f(CWEVBACKEND_ALL\fR" 4 |
502 | .IX Item "EVBACKEND_ALL" |
513 | .IX Item "EVBACKEND_ALL" |
… | |
… | |
552 | Destroys the default loop again (frees all memory and kernel state |
563 | Destroys the default loop again (frees all memory and kernel state |
553 | etc.). None of the active event watchers will be stopped in the normal |
564 | etc.). None of the active event watchers will be stopped in the normal |
554 | sense, so e.g. \f(CW\*(C`ev_is_active\*(C'\fR might still return true. It is your |
565 | sense, so e.g. \f(CW\*(C`ev_is_active\*(C'\fR might still return true. It is your |
555 | responsibility to either stop all watchers cleanly yoursef \fIbefore\fR |
566 | responsibility to either stop all watchers cleanly yoursef \fIbefore\fR |
556 | calling this function, or cope with the fact afterwards (which is usually |
567 | calling this function, or cope with the fact afterwards (which is usually |
557 | the easiest thing, youc na just ignore the watchers and/or \f(CW\*(C`free ()\*(C'\fR them |
568 | the easiest thing, you can just ignore the watchers and/or \f(CW\*(C`free ()\*(C'\fR them |
558 | for example). |
569 | for example). |
|
|
570 | .Sp |
|
|
571 | Note that certain global state, such as signal state, will not be freed by |
|
|
572 | this function, and related watchers (such as signal and child watchers) |
|
|
573 | would need to be stopped manually. |
|
|
574 | .Sp |
|
|
575 | In general it is not advisable to call this function except in the |
|
|
576 | rare occasion where you really need to free e.g. the signal handling |
|
|
577 | pipe fds. If you need dynamically allocated loops it is better to use |
|
|
578 | \&\f(CW\*(C`ev_loop_new\*(C'\fR and \f(CW\*(C`ev_loop_destroy\*(C'\fR). |
559 | .IP "ev_loop_destroy (loop)" 4 |
579 | .IP "ev_loop_destroy (loop)" 4 |
560 | .IX Item "ev_loop_destroy (loop)" |
580 | .IX Item "ev_loop_destroy (loop)" |
561 | Like \f(CW\*(C`ev_default_destroy\*(C'\fR, but destroys an event loop created by an |
581 | Like \f(CW\*(C`ev_default_destroy\*(C'\fR, but destroys an event loop created by an |
562 | earlier call to \f(CW\*(C`ev_loop_new\*(C'\fR. |
582 | earlier call to \f(CW\*(C`ev_loop_new\*(C'\fR. |
563 | .IP "ev_default_fork ()" 4 |
583 | .IP "ev_default_fork ()" 4 |
… | |
… | |
604 | .IX Item "ev_tstamp ev_now (loop)" |
624 | .IX Item "ev_tstamp ev_now (loop)" |
605 | Returns the current \*(L"event loop time\*(R", which is the time the event loop |
625 | Returns the current \*(L"event loop time\*(R", which is the time the event loop |
606 | received events and started processing them. This timestamp does not |
626 | received events and started processing them. This timestamp does not |
607 | change as long as callbacks are being processed, and this is also the base |
627 | change as long as callbacks are being processed, and this is also the base |
608 | time used for relative timers. You can treat it as the timestamp of the |
628 | time used for relative timers. You can treat it as the timestamp of the |
609 | event occuring (or more correctly, libev finding out about it). |
629 | event occurring (or more correctly, libev finding out about it). |
610 | .IP "ev_loop (loop, int flags)" 4 |
630 | .IP "ev_loop (loop, int flags)" 4 |
611 | .IX Item "ev_loop (loop, int flags)" |
631 | .IX Item "ev_loop (loop, int flags)" |
612 | Finally, this is it, the event handler. This function usually is called |
632 | Finally, this is it, the event handler. This function usually is called |
613 | after you initialised all your watchers and you want to start handling |
633 | after you initialised all your watchers and you want to start handling |
614 | events. |
634 | events. |
… | |
… | |
634 | libev watchers. However, a pair of \f(CW\*(C`ev_prepare\*(C'\fR/\f(CW\*(C`ev_check\*(C'\fR watchers is |
654 | libev watchers. However, a pair of \f(CW\*(C`ev_prepare\*(C'\fR/\f(CW\*(C`ev_check\*(C'\fR watchers is |
635 | usually a better approach for this kind of thing. |
655 | usually a better approach for this kind of thing. |
636 | .Sp |
656 | .Sp |
637 | Here are the gory details of what \f(CW\*(C`ev_loop\*(C'\fR does: |
657 | Here are the gory details of what \f(CW\*(C`ev_loop\*(C'\fR does: |
638 | .Sp |
658 | .Sp |
639 | .Vb 18 |
659 | .Vb 19 |
|
|
660 | \& - Before the first iteration, call any pending watchers. |
640 | \& * If there are no active watchers (reference count is zero), return. |
661 | \& * If there are no active watchers (reference count is zero), return. |
641 | \& - Queue prepare watchers and then call all outstanding watchers. |
662 | \& - Queue all prepare watchers and then call all outstanding watchers. |
642 | \& - If we have been forked, recreate the kernel state. |
663 | \& - If we have been forked, recreate the kernel state. |
643 | \& - Update the kernel state with all outstanding changes. |
664 | \& - Update the kernel state with all outstanding changes. |
644 | \& - Update the "event loop time". |
665 | \& - Update the "event loop time". |
645 | \& - Calculate for how long to block. |
666 | \& - Calculate for how long to block. |
646 | \& - Block the process, waiting for any events. |
667 | \& - Block the process, waiting for any events. |
… | |
… | |
889 | .IP "bool ev_is_pending (ev_TYPE *watcher)" 4 |
910 | .IP "bool ev_is_pending (ev_TYPE *watcher)" 4 |
890 | .IX Item "bool ev_is_pending (ev_TYPE *watcher)" |
911 | .IX Item "bool ev_is_pending (ev_TYPE *watcher)" |
891 | Returns a true value iff the watcher is pending, (i.e. it has outstanding |
912 | Returns a true value iff the watcher is pending, (i.e. it has outstanding |
892 | events but its callback has not yet been invoked). As long as a watcher |
913 | events but its callback has not yet been invoked). As long as a watcher |
893 | is pending (but not active) you must not call an init function on it (but |
914 | is pending (but not active) you must not call an init function on it (but |
894 | \&\f(CW\*(C`ev_TYPE_set\*(C'\fR is safe) and you must make sure the watcher is available to |
915 | \&\f(CW\*(C`ev_TYPE_set\*(C'\fR is safe), you must not change its priority, and you must |
895 | libev (e.g. you cnanot \f(CW\*(C`free ()\*(C'\fR it). |
916 | make sure the watcher is available to libev (e.g. you cannot \f(CW\*(C`free ()\*(C'\fR |
|
|
917 | it). |
896 | .IP "callback ev_cb (ev_TYPE *watcher)" 4 |
918 | .IP "callback ev_cb (ev_TYPE *watcher)" 4 |
897 | .IX Item "callback ev_cb (ev_TYPE *watcher)" |
919 | .IX Item "callback ev_cb (ev_TYPE *watcher)" |
898 | Returns the callback currently set on the watcher. |
920 | Returns the callback currently set on the watcher. |
899 | .IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 |
921 | .IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 |
900 | .IX Item "ev_cb_set (ev_TYPE *watcher, callback)" |
922 | .IX Item "ev_cb_set (ev_TYPE *watcher, callback)" |
… | |
… | |
918 | watchers on the same event and make sure one is called first. |
940 | watchers on the same event and make sure one is called first. |
919 | .Sp |
941 | .Sp |
920 | If you need to suppress invocation when higher priority events are pending |
942 | If you need to suppress invocation when higher priority events are pending |
921 | you need to look at \f(CW\*(C`ev_idle\*(C'\fR watchers, which provide this functionality. |
943 | you need to look at \f(CW\*(C`ev_idle\*(C'\fR watchers, which provide this functionality. |
922 | .Sp |
944 | .Sp |
|
|
945 | You \fImust not\fR change the priority of a watcher as long as it is active or |
|
|
946 | pending. |
|
|
947 | .Sp |
923 | The default priority used by watchers when no priority has been set is |
948 | The default priority used by watchers when no priority has been set is |
924 | always \f(CW0\fR, which is supposed to not be too high and not be too low :). |
949 | always \f(CW0\fR, which is supposed to not be too high and not be too low :). |
925 | .Sp |
950 | .Sp |
926 | Setting a priority outside the range of \f(CW\*(C`EV_MINPRI\*(C'\fR to \f(CW\*(C`EV_MAXPRI\*(C'\fR is |
951 | Setting a priority outside the range of \f(CW\*(C`EV_MINPRI\*(C'\fR to \f(CW\*(C`EV_MAXPRI\*(C'\fR is |
927 | fine, as long as you do not mind that the priority value you query might |
952 | fine, as long as you do not mind that the priority value you query might |
928 | or might not have been adjusted to be within valid range. |
953 | or might not have been adjusted to be within valid range. |
|
|
954 | .IP "ev_invoke (loop, ev_TYPE *watcher, int revents)" 4 |
|
|
955 | .IX Item "ev_invoke (loop, ev_TYPE *watcher, int revents)" |
|
|
956 | 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 |
|
|
957 | \&\f(CW\*(C`loop\*(C'\fR nor \f(CW\*(C`revents\*(C'\fR need to be valid as long as the watcher callback |
|
|
958 | can deal with that fact. |
|
|
959 | .IP "int ev_clear_pending (loop, ev_TYPE *watcher)" 4 |
|
|
960 | .IX Item "int ev_clear_pending (loop, ev_TYPE *watcher)" |
|
|
961 | If the watcher is pending, this function returns clears its pending status |
|
|
962 | and returns its \f(CW\*(C`revents\*(C'\fR bitset (as if its callback was invoked). If the |
|
|
963 | watcher isn't pending it does nothing and returns \f(CW0\fR. |
929 | .Sh "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0" |
964 | .Sh "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0" |
930 | .IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER" |
965 | .IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER" |
931 | Each watcher has, by default, a member \f(CW\*(C`void *data\*(C'\fR that you can change |
966 | Each watcher has, by default, a member \f(CW\*(C`void *data\*(C'\fR that you can change |
932 | and read at any time, libev will completely ignore it. This can be used |
967 | and read at any time, libev will completely ignore it. This can be used |
933 | to associate arbitrary data with your watcher. If you need more data and |
968 | to associate arbitrary data with your watcher. If you need more data and |
… | |
… | |
1047 | If you cannot run the fd in non-blocking mode (for example you should not |
1082 | If you cannot run the fd in non-blocking mode (for example you should not |
1048 | play around with an Xlib connection), then you have to seperately re-test |
1083 | play around with an Xlib connection), then you have to seperately re-test |
1049 | whether a file descriptor is really ready with a known-to-be good interface |
1084 | whether a file descriptor is really ready with a known-to-be good interface |
1050 | such as poll (fortunately in our Xlib example, Xlib already does this on |
1085 | such as poll (fortunately in our Xlib example, Xlib already does this on |
1051 | its own, so its quite safe to use). |
1086 | its own, so its quite safe to use). |
|
|
1087 | .PP |
|
|
1088 | \fIThe special problem of disappearing file descriptors\fR |
|
|
1089 | .IX Subsection "The special problem of disappearing file descriptors" |
|
|
1090 | .PP |
|
|
1091 | Some backends (e.g. kqueue, epoll) need to be told about closing a file |
|
|
1092 | descriptor (either by calling \f(CW\*(C`close\*(C'\fR explicitly or by any other means, |
|
|
1093 | such as \f(CW\*(C`dup\*(C'\fR). The reason is that you register interest in some file |
|
|
1094 | descriptor, but when it goes away, the operating system will silently drop |
|
|
1095 | this interest. If another file descriptor with the same number then is |
|
|
1096 | registered with libev, there is no efficient way to see that this is, in |
|
|
1097 | fact, a different file descriptor. |
|
|
1098 | .PP |
|
|
1099 | To avoid having to explicitly tell libev about such cases, libev follows |
|
|
1100 | the following policy: Each time \f(CW\*(C`ev_io_set\*(C'\fR is being called, libev |
|
|
1101 | will assume that this is potentially a new file descriptor, otherwise |
|
|
1102 | it is assumed that the file descriptor stays the same. That means that |
|
|
1103 | 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 |
|
|
1104 | descriptor even if the file descriptor number itself did not change. |
|
|
1105 | .PP |
|
|
1106 | This is how one would do it normally anyway, the important point is that |
|
|
1107 | the libev application should not optimise around libev but should leave |
|
|
1108 | optimisations to libev. |
|
|
1109 | .PP |
|
|
1110 | \fIThs special problem of dup'ed file descriptors\fR |
|
|
1111 | .IX Subsection "Ths special problem of dup'ed file descriptors" |
|
|
1112 | .PP |
|
|
1113 | Some backends (e.g. epoll), cannot register events for file descriptors, |
|
|
1114 | but only events for the underlying file descriptions. That menas when you |
|
|
1115 | have \f(CW\*(C`dup ()\*(C'\fR'ed file descriptors and register events for them, only one |
|
|
1116 | file descriptor might actually receive events. |
|
|
1117 | .PP |
|
|
1118 | There is no workaorund possible except not registering events |
|
|
1119 | for potentially \f(CW\*(C`dup ()\*(C'\fR'ed file descriptors or to resort to |
|
|
1120 | \&\f(CW\*(C`EVBACKEND_SELECT\*(C'\fR or \f(CW\*(C`EVBACKEND_POLL\*(C'\fR. |
|
|
1121 | .PP |
|
|
1122 | \fIThe special problem of fork\fR |
|
|
1123 | .IX Subsection "The special problem of fork" |
|
|
1124 | .PP |
|
|
1125 | Some backends (epoll, kqueue) do not support \f(CW\*(C`fork ()\*(C'\fR at all or exhibit |
|
|
1126 | useless behaviour. Libev fully supports fork, but needs to be told about |
|
|
1127 | it in the child. |
|
|
1128 | .PP |
|
|
1129 | To support fork in your programs, you either have to call |
|
|
1130 | \&\f(CW\*(C`ev_default_fork ()\*(C'\fR or \f(CW\*(C`ev_loop_fork ()\*(C'\fR after a fork in the child, |
|
|
1131 | enable \f(CW\*(C`EVFLAG_FORKCHECK\*(C'\fR, or resort to \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR or |
|
|
1132 | \&\f(CW\*(C`EVBACKEND_POLL\*(C'\fR. |
|
|
1133 | .PP |
|
|
1134 | \fIWatcher-Specific Functions\fR |
|
|
1135 | .IX Subsection "Watcher-Specific Functions" |
1052 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
1136 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
1053 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
1137 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
1054 | .PD 0 |
1138 | .PD 0 |
1055 | .IP "ev_io_set (ev_io *, int fd, int events)" 4 |
1139 | .IP "ev_io_set (ev_io *, int fd, int events)" 4 |
1056 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
1140 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
… | |
… | |
1109 | .Ve |
1193 | .Ve |
1110 | .PP |
1194 | .PP |
1111 | The callback is guarenteed to be invoked only when its timeout has passed, |
1195 | The callback is guarenteed to be invoked only when its timeout has passed, |
1112 | but if multiple timers become ready during the same loop iteration then |
1196 | but if multiple timers become ready during the same loop iteration then |
1113 | order of execution is undefined. |
1197 | order of execution is undefined. |
|
|
1198 | .PP |
|
|
1199 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1200 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1114 | .IP "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" 4 |
1201 | .IP "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" 4 |
1115 | .IX Item "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" |
1202 | .IX Item "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" |
1116 | .PD 0 |
1203 | .PD 0 |
1117 | .IP "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)" 4 |
1204 | .IP "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)" 4 |
1118 | .IX Item "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)" |
1205 | .IX Item "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)" |
… | |
… | |
1220 | but on wallclock time (absolute time). You can tell a periodic watcher |
1307 | but on wallclock time (absolute time). You can tell a periodic watcher |
1221 | to trigger \*(L"at\*(R" some specific point in time. For example, if you tell a |
1308 | to trigger \*(L"at\*(R" some specific point in time. For example, if you tell a |
1222 | periodic watcher to trigger in 10 seconds (by specifiying e.g. \f(CW\*(C`ev_now () |
1309 | periodic watcher to trigger in 10 seconds (by specifiying e.g. \f(CW\*(C`ev_now () |
1223 | + 10.\*(C'\fR) and then reset your system clock to the last year, then it will |
1310 | + 10.\*(C'\fR) and then reset your system clock to the last year, then it will |
1224 | take a year to trigger the event (unlike an \f(CW\*(C`ev_timer\*(C'\fR, which would trigger |
1311 | take a year to trigger the event (unlike an \f(CW\*(C`ev_timer\*(C'\fR, which would trigger |
1225 | roughly 10 seconds later and of course not if you reset your system time |
1312 | roughly 10 seconds later). |
1226 | again). |
|
|
1227 | .PP |
1313 | .PP |
1228 | They can also be used to implement vastly more complex timers, such as |
1314 | They can also be used to implement vastly more complex timers, such as |
1229 | triggering an event on eahc midnight, local time. |
1315 | triggering an event on each midnight, local time or other, complicated, |
|
|
1316 | rules. |
1230 | .PP |
1317 | .PP |
1231 | As with timers, the callback is guarenteed to be invoked only when the |
1318 | As with timers, the callback is guarenteed to be invoked only when the |
1232 | time (\f(CW\*(C`at\*(C'\fR) has been passed, but if multiple periodic timers become ready |
1319 | time (\f(CW\*(C`at\*(C'\fR) has been passed, but if multiple periodic timers become ready |
1233 | during the same loop iteration then order of execution is undefined. |
1320 | during the same loop iteration then order of execution is undefined. |
|
|
1321 | .PP |
|
|
1322 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1323 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1234 | .IP "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" 4 |
1324 | .IP "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" 4 |
1235 | .IX Item "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" |
1325 | .IX Item "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" |
1236 | .PD 0 |
1326 | .PD 0 |
1237 | .IP "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" 4 |
1327 | .IP "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" 4 |
1238 | .IX Item "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" |
1328 | .IX Item "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" |
1239 | .PD |
1329 | .PD |
1240 | Lots of arguments, lets sort it out... There are basically three modes of |
1330 | Lots of arguments, lets sort it out... There are basically three modes of |
1241 | operation, and we will explain them from simplest to complex: |
1331 | operation, and we will explain them from simplest to complex: |
1242 | .RS 4 |
1332 | .RS 4 |
1243 | .IP "* absolute timer (interval = reschedule_cb = 0)" 4 |
1333 | .IP "* absolute timer (at = time, interval = reschedule_cb = 0)" 4 |
1244 | .IX Item "absolute timer (interval = reschedule_cb = 0)" |
1334 | .IX Item "absolute timer (at = time, interval = reschedule_cb = 0)" |
1245 | In this configuration the watcher triggers an event at the wallclock time |
1335 | In this configuration the watcher triggers an event at the wallclock time |
1246 | \&\f(CW\*(C`at\*(C'\fR and doesn't repeat. It will not adjust when a time jump occurs, |
1336 | \&\f(CW\*(C`at\*(C'\fR and doesn't repeat. It will not adjust when a time jump occurs, |
1247 | that is, if it is to be run at January 1st 2011 then it will run when the |
1337 | that is, if it is to be run at January 1st 2011 then it will run when the |
1248 | system time reaches or surpasses this time. |
1338 | system time reaches or surpasses this time. |
1249 | .IP "* non-repeating interval timer (interval > 0, reschedule_cb = 0)" 4 |
1339 | .IP "* non-repeating interval timer (at = offset, interval > 0, reschedule_cb = 0)" 4 |
1250 | .IX Item "non-repeating interval timer (interval > 0, reschedule_cb = 0)" |
1340 | .IX Item "non-repeating interval timer (at = offset, interval > 0, reschedule_cb = 0)" |
1251 | In this mode the watcher will always be scheduled to time out at the next |
1341 | In this mode the watcher will always be scheduled to time out at the next |
1252 | \&\f(CW\*(C`at + N * interval\*(C'\fR time (for some integer N) and then repeat, regardless |
1342 | \&\f(CW\*(C`at + N * interval\*(C'\fR time (for some integer N, which can also be negative) |
1253 | of any time jumps. |
1343 | and then repeat, regardless of any time jumps. |
1254 | .Sp |
1344 | .Sp |
1255 | This can be used to create timers that do not drift with respect to system |
1345 | This can be used to create timers that do not drift with respect to system |
1256 | time: |
1346 | time: |
1257 | .Sp |
1347 | .Sp |
1258 | .Vb 1 |
1348 | .Vb 1 |
… | |
… | |
1265 | by 3600. |
1355 | by 3600. |
1266 | .Sp |
1356 | .Sp |
1267 | Another way to think about it (for the mathematically inclined) is that |
1357 | Another way to think about it (for the mathematically inclined) is that |
1268 | \&\f(CW\*(C`ev_periodic\*(C'\fR will try to run the callback in this mode at the next possible |
1358 | \&\f(CW\*(C`ev_periodic\*(C'\fR will try to run the callback in this mode at the next possible |
1269 | time where \f(CW\*(C`time = at (mod interval)\*(C'\fR, regardless of any time jumps. |
1359 | time where \f(CW\*(C`time = at (mod interval)\*(C'\fR, regardless of any time jumps. |
|
|
1360 | .Sp |
|
|
1361 | For numerical stability it is preferable that the \f(CW\*(C`at\*(C'\fR value is near |
|
|
1362 | \&\f(CW\*(C`ev_now ()\*(C'\fR (the current time), but there is no range requirement for |
|
|
1363 | this value. |
1270 | .IP "* manual reschedule mode (reschedule_cb = callback)" 4 |
1364 | .IP "* manual reschedule mode (at and interval ignored, reschedule_cb = callback)" 4 |
1271 | .IX Item "manual reschedule mode (reschedule_cb = callback)" |
1365 | .IX Item "manual reschedule mode (at and interval ignored, reschedule_cb = callback)" |
1272 | In this mode the values for \f(CW\*(C`interval\*(C'\fR and \f(CW\*(C`at\*(C'\fR are both being |
1366 | In this mode the values for \f(CW\*(C`interval\*(C'\fR and \f(CW\*(C`at\*(C'\fR are both being |
1273 | ignored. Instead, each time the periodic watcher gets scheduled, the |
1367 | ignored. Instead, each time the periodic watcher gets scheduled, the |
1274 | reschedule callback will be called with the watcher as first, and the |
1368 | reschedule callback will be called with the watcher as first, and the |
1275 | current time as second argument. |
1369 | current time as second argument. |
1276 | .Sp |
1370 | .Sp |
1277 | \&\s-1NOTE:\s0 \fIThis callback \s-1MUST\s0 \s-1NOT\s0 stop or destroy any periodic watcher, |
1371 | \&\s-1NOTE:\s0 \fIThis callback \s-1MUST\s0 \s-1NOT\s0 stop or destroy any periodic watcher, |
1278 | ever, or make any event loop modifications\fR. If you need to stop it, |
1372 | ever, or make any event loop modifications\fR. If you need to stop it, |
1279 | return \f(CW\*(C`now + 1e30\*(C'\fR (or so, fudge fudge) and stop it afterwards (e.g. by |
1373 | return \f(CW\*(C`now + 1e30\*(C'\fR (or so, fudge fudge) and stop it afterwards (e.g. by |
1280 | starting a prepare watcher). |
1374 | starting an \f(CW\*(C`ev_prepare\*(C'\fR watcher, which is legal). |
1281 | .Sp |
1375 | .Sp |
1282 | Its prototype is \f(CW\*(C`ev_tstamp (*reschedule_cb)(struct ev_periodic *w, |
1376 | Its prototype is \f(CW\*(C`ev_tstamp (*reschedule_cb)(struct ev_periodic *w, |
1283 | ev_tstamp now)\*(C'\fR, e.g.: |
1377 | ev_tstamp now)\*(C'\fR, e.g.: |
1284 | .Sp |
1378 | .Sp |
1285 | .Vb 4 |
1379 | .Vb 4 |
… | |
… | |
1309 | .IX Item "ev_periodic_again (loop, ev_periodic *)" |
1403 | .IX Item "ev_periodic_again (loop, ev_periodic *)" |
1310 | Simply stops and restarts the periodic watcher again. This is only useful |
1404 | Simply stops and restarts the periodic watcher again. This is only useful |
1311 | when you changed some parameters or the reschedule callback would return |
1405 | when you changed some parameters or the reschedule callback would return |
1312 | a different time than the last time it was called (e.g. in a crond like |
1406 | a different time than the last time it was called (e.g. in a crond like |
1313 | program when the crontabs have changed). |
1407 | program when the crontabs have changed). |
|
|
1408 | .IP "ev_tstamp offset [read\-write]" 4 |
|
|
1409 | .IX Item "ev_tstamp offset [read-write]" |
|
|
1410 | When repeating, this contains the offset value, otherwise this is the |
|
|
1411 | absolute point in time (the \f(CW\*(C`at\*(C'\fR value passed to \f(CW\*(C`ev_periodic_set\*(C'\fR). |
|
|
1412 | .Sp |
|
|
1413 | Can be modified any time, but changes only take effect when the periodic |
|
|
1414 | timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called. |
1314 | .IP "ev_tstamp interval [read\-write]" 4 |
1415 | .IP "ev_tstamp interval [read\-write]" 4 |
1315 | .IX Item "ev_tstamp interval [read-write]" |
1416 | .IX Item "ev_tstamp interval [read-write]" |
1316 | The current interval value. Can be modified any time, but changes only |
1417 | The current interval value. Can be modified any time, but changes only |
1317 | take effect when the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being |
1418 | take effect when the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being |
1318 | called. |
1419 | called. |
1319 | .IP "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read\-write]" 4 |
1420 | .IP "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read\-write]" 4 |
1320 | .IX Item "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write]" |
1421 | .IX Item "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write]" |
1321 | The current reschedule callback, or \f(CW0\fR, if this functionality is |
1422 | The current reschedule callback, or \f(CW0\fR, if this functionality is |
1322 | switched off. Can be changed any time, but changes only take effect when |
1423 | switched off. Can be changed any time, but changes only take effect when |
1323 | the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called. |
1424 | the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called. |
|
|
1425 | .IP "ev_tstamp at [read\-only]" 4 |
|
|
1426 | .IX Item "ev_tstamp at [read-only]" |
|
|
1427 | When active, contains the absolute time that the watcher is supposed to |
|
|
1428 | trigger next. |
1324 | .PP |
1429 | .PP |
1325 | Example: Call a callback every hour, or, more precisely, whenever the |
1430 | Example: Call a callback every hour, or, more precisely, whenever the |
1326 | system clock is divisible by 3600. The callback invocation times have |
1431 | system clock is divisible by 3600. The callback invocation times have |
1327 | potentially a lot of jittering, but good long-term stability. |
1432 | potentially a lot of jittering, but good long-term stability. |
1328 | .PP |
1433 | .PP |
… | |
… | |
1378 | first watcher gets started will libev actually register a signal watcher |
1483 | first watcher gets started will libev actually register a signal watcher |
1379 | with the kernel (thus it coexists with your own signal handlers as long |
1484 | with the kernel (thus it coexists with your own signal handlers as long |
1380 | as you don't register any with libev). Similarly, when the last signal |
1485 | as you don't register any with libev). Similarly, when the last signal |
1381 | watcher for a signal is stopped libev will reset the signal handler to |
1486 | watcher for a signal is stopped libev will reset the signal handler to |
1382 | \&\s-1SIG_DFL\s0 (regardless of what it was set to before). |
1487 | \&\s-1SIG_DFL\s0 (regardless of what it was set to before). |
|
|
1488 | .PP |
|
|
1489 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1490 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1383 | .IP "ev_signal_init (ev_signal *, callback, int signum)" 4 |
1491 | .IP "ev_signal_init (ev_signal *, callback, int signum)" 4 |
1384 | .IX Item "ev_signal_init (ev_signal *, callback, int signum)" |
1492 | .IX Item "ev_signal_init (ev_signal *, callback, int signum)" |
1385 | .PD 0 |
1493 | .PD 0 |
1386 | .IP "ev_signal_set (ev_signal *, int signum)" 4 |
1494 | .IP "ev_signal_set (ev_signal *, int signum)" 4 |
1387 | .IX Item "ev_signal_set (ev_signal *, int signum)" |
1495 | .IX Item "ev_signal_set (ev_signal *, int signum)" |
… | |
… | |
1394 | .ie n .Sh """ev_child"" \- watch out for process status changes" |
1502 | .ie n .Sh """ev_child"" \- watch out for process status changes" |
1395 | .el .Sh "\f(CWev_child\fP \- watch out for process status changes" |
1503 | .el .Sh "\f(CWev_child\fP \- watch out for process status changes" |
1396 | .IX Subsection "ev_child - watch out for process status changes" |
1504 | .IX Subsection "ev_child - watch out for process status changes" |
1397 | Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to |
1505 | Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to |
1398 | some child status changes (most typically when a child of yours dies). |
1506 | some child status changes (most typically when a child of yours dies). |
|
|
1507 | .PP |
|
|
1508 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1509 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1399 | .IP "ev_child_init (ev_child *, callback, int pid)" 4 |
1510 | .IP "ev_child_init (ev_child *, callback, int pid)" 4 |
1400 | .IX Item "ev_child_init (ev_child *, callback, int pid)" |
1511 | .IX Item "ev_child_init (ev_child *, callback, int pid)" |
1401 | .PD 0 |
1512 | .PD 0 |
1402 | .IP "ev_child_set (ev_child *, int pid)" 4 |
1513 | .IP "ev_child_set (ev_child *, int pid)" 4 |
1403 | .IX Item "ev_child_set (ev_child *, int pid)" |
1514 | .IX Item "ev_child_set (ev_child *, int pid)" |
… | |
… | |
1468 | reader). Inotify will be used to give hints only and should not change the |
1579 | reader). Inotify will be used to give hints only and should not change the |
1469 | semantics of \f(CW\*(C`ev_stat\*(C'\fR watchers, which means that libev sometimes needs |
1580 | semantics of \f(CW\*(C`ev_stat\*(C'\fR watchers, which means that libev sometimes needs |
1470 | to fall back to regular polling again even with inotify, but changes are |
1581 | to fall back to regular polling again even with inotify, but changes are |
1471 | usually detected immediately, and if the file exists there will be no |
1582 | usually detected immediately, and if the file exists there will be no |
1472 | polling. |
1583 | polling. |
|
|
1584 | .PP |
|
|
1585 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1586 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1473 | .IP "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" 4 |
1587 | .IP "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" 4 |
1474 | .IX Item "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" |
1588 | .IX Item "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" |
1475 | .PD 0 |
1589 | .PD 0 |
1476 | .IP "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" 4 |
1590 | .IP "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" 4 |
1477 | .IX Item "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" |
1591 | .IX Item "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" |
… | |
… | |
1556 | .PP |
1670 | .PP |
1557 | Apart from keeping your process non-blocking (which is a useful |
1671 | Apart from keeping your process non-blocking (which is a useful |
1558 | effect on its own sometimes), idle watchers are a good place to do |
1672 | effect on its own sometimes), idle watchers are a good place to do |
1559 | \&\*(L"pseudo\-background processing\*(R", or delay processing stuff to after the |
1673 | \&\*(L"pseudo\-background processing\*(R", or delay processing stuff to after the |
1560 | event loop has handled all outstanding events. |
1674 | event loop has handled all outstanding events. |
|
|
1675 | .PP |
|
|
1676 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1677 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1561 | .IP "ev_idle_init (ev_signal *, callback)" 4 |
1678 | .IP "ev_idle_init (ev_signal *, callback)" 4 |
1562 | .IX Item "ev_idle_init (ev_signal *, callback)" |
1679 | .IX Item "ev_idle_init (ev_signal *, callback)" |
1563 | Initialises and configures the idle watcher \- it has no parameters of any |
1680 | Initialises and configures the idle watcher \- it has no parameters of any |
1564 | kind. There is a \f(CW\*(C`ev_idle_set\*(C'\fR macro, but using it is utterly pointless, |
1681 | kind. There is a \f(CW\*(C`ev_idle_set\*(C'\fR macro, but using it is utterly pointless, |
1565 | believe me. |
1682 | believe me. |
… | |
… | |
1620 | are ready to run (it's actually more complicated: it only runs coroutines |
1737 | are ready to run (it's actually more complicated: it only runs coroutines |
1621 | with priority higher than or equal to the event loop and one coroutine |
1738 | with priority higher than or equal to the event loop and one coroutine |
1622 | of lower priority, but only once, using idle watchers to keep the event |
1739 | of lower priority, but only once, using idle watchers to keep the event |
1623 | loop from blocking if lower-priority coroutines are active, thus mapping |
1740 | loop from blocking if lower-priority coroutines are active, thus mapping |
1624 | low-priority coroutines to idle/background tasks). |
1741 | low-priority coroutines to idle/background tasks). |
|
|
1742 | .PP |
|
|
1743 | It is recommended to give \f(CW\*(C`ev_check\*(C'\fR watchers highest (\f(CW\*(C`EV_MAXPRI\*(C'\fR) |
|
|
1744 | priority, to ensure that they are being run before any other watchers |
|
|
1745 | after the poll. Also, \f(CW\*(C`ev_check\*(C'\fR watchers (and \f(CW\*(C`ev_prepare\*(C'\fR watchers, |
|
|
1746 | too) should not activate (\*(L"feed\*(R") events into libev. While libev fully |
|
|
1747 | supports this, they will be called before other \f(CW\*(C`ev_check\*(C'\fR watchers did |
|
|
1748 | their job. As \f(CW\*(C`ev_check\*(C'\fR watchers are often used to embed other event |
|
|
1749 | loops those other event loops might be in an unusable state until their |
|
|
1750 | \&\f(CW\*(C`ev_check\*(C'\fR watcher ran (always remind yourself to coexist peacefully with |
|
|
1751 | others). |
|
|
1752 | .PP |
|
|
1753 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1754 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1625 | .IP "ev_prepare_init (ev_prepare *, callback)" 4 |
1755 | .IP "ev_prepare_init (ev_prepare *, callback)" 4 |
1626 | .IX Item "ev_prepare_init (ev_prepare *, callback)" |
1756 | .IX Item "ev_prepare_init (ev_prepare *, callback)" |
1627 | .PD 0 |
1757 | .PD 0 |
1628 | .IP "ev_check_init (ev_check *, callback)" 4 |
1758 | .IP "ev_check_init (ev_check *, callback)" 4 |
1629 | .IX Item "ev_check_init (ev_check *, callback)" |
1759 | .IX Item "ev_check_init (ev_check *, callback)" |
1630 | .PD |
1760 | .PD |
1631 | Initialises and configures the prepare or check watcher \- they have no |
1761 | Initialises and configures the prepare or check watcher \- they have no |
1632 | parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR |
1762 | parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR |
1633 | macros, but using them is utterly, utterly and completely pointless. |
1763 | macros, but using them is utterly, utterly and completely pointless. |
1634 | .PP |
1764 | .PP |
1635 | Example: To include a library such as adns, you would add \s-1IO\s0 watchers |
1765 | There are a number of principal ways to embed other event loops or modules |
1636 | and a timeout watcher in a prepare handler, as required by libadns, and |
1766 | into libev. Here are some ideas on how to include libadns into libev |
|
|
1767 | (there is a Perl module named \f(CW\*(C`EV::ADNS\*(C'\fR that does this, which you could |
|
|
1768 | use for an actually working example. Another Perl module named \f(CW\*(C`EV::Glib\*(C'\fR |
|
|
1769 | embeds a Glib main context into libev, and finally, \f(CW\*(C`Glib::EV\*(C'\fR embeds \s-1EV\s0 |
|
|
1770 | into the Glib event loop). |
|
|
1771 | .PP |
|
|
1772 | Method 1: Add \s-1IO\s0 watchers and a timeout watcher in a prepare handler, |
1637 | in a check watcher, destroy them and call into libadns. What follows is |
1773 | and in a check watcher, destroy them and call into libadns. What follows |
1638 | pseudo-code only of course: |
1774 | is pseudo-code only of course. This requires you to either use a low |
|
|
1775 | priority for the check watcher or use \f(CW\*(C`ev_clear_pending\*(C'\fR explicitly, as |
|
|
1776 | the callbacks for the IO/timeout watchers might not have been called yet. |
1639 | .PP |
1777 | .PP |
1640 | .Vb 2 |
1778 | .Vb 2 |
1641 | \& static ev_io iow [nfd]; |
1779 | \& static ev_io iow [nfd]; |
1642 | \& static ev_timer tw; |
1780 | \& static ev_timer tw; |
1643 | .Ve |
1781 | .Ve |
1644 | .PP |
1782 | .PP |
1645 | .Vb 9 |
1783 | .Vb 4 |
1646 | \& static void |
1784 | \& static void |
1647 | \& io_cb (ev_loop *loop, ev_io *w, int revents) |
1785 | \& io_cb (ev_loop *loop, ev_io *w, int revents) |
1648 | \& { |
1786 | \& { |
1649 | \& // set the relevant poll flags |
|
|
1650 | \& // could also call adns_processreadable etc. here |
|
|
1651 | \& struct pollfd *fd = (struct pollfd *)w->data; |
|
|
1652 | \& if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
|
|
1653 | \& if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
|
|
1654 | \& } |
1787 | \& } |
1655 | .Ve |
1788 | .Ve |
1656 | .PP |
1789 | .PP |
1657 | .Vb 8 |
1790 | .Vb 8 |
1658 | \& // create io watchers for each fd and a timer before blocking |
1791 | \& // create io watchers for each fd and a timer before blocking |
… | |
… | |
1670 | \& ev_timer_init (&tw, 0, timeout * 1e-3); |
1803 | \& ev_timer_init (&tw, 0, timeout * 1e-3); |
1671 | \& ev_timer_start (loop, &tw); |
1804 | \& ev_timer_start (loop, &tw); |
1672 | .Ve |
1805 | .Ve |
1673 | .PP |
1806 | .PP |
1674 | .Vb 6 |
1807 | .Vb 6 |
1675 | \& // create on ev_io per pollfd |
1808 | \& // create one ev_io per pollfd |
1676 | \& for (int i = 0; i < nfd; ++i) |
1809 | \& for (int i = 0; i < nfd; ++i) |
1677 | \& { |
1810 | \& { |
1678 | \& ev_io_init (iow + i, io_cb, fds [i].fd, |
1811 | \& ev_io_init (iow + i, io_cb, fds [i].fd, |
1679 | \& ((fds [i].events & POLLIN ? EV_READ : 0) |
1812 | \& ((fds [i].events & POLLIN ? EV_READ : 0) |
1680 | \& | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
1813 | \& | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
1681 | .Ve |
1814 | .Ve |
1682 | .PP |
1815 | .PP |
1683 | .Vb 5 |
1816 | .Vb 4 |
1684 | \& fds [i].revents = 0; |
1817 | \& fds [i].revents = 0; |
1685 | \& iow [i].data = fds + i; |
|
|
1686 | \& ev_io_start (loop, iow + i); |
1818 | \& ev_io_start (loop, iow + i); |
1687 | \& } |
1819 | \& } |
1688 | \& } |
1820 | \& } |
1689 | .Ve |
1821 | .Ve |
1690 | .PP |
1822 | .PP |
… | |
… | |
1694 | \& adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
1826 | \& adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
1695 | \& { |
1827 | \& { |
1696 | \& ev_timer_stop (loop, &tw); |
1828 | \& ev_timer_stop (loop, &tw); |
1697 | .Ve |
1829 | .Ve |
1698 | .PP |
1830 | .PP |
1699 | .Vb 2 |
1831 | .Vb 8 |
1700 | \& for (int i = 0; i < nfd; ++i) |
1832 | \& for (int i = 0; i < nfd; ++i) |
|
|
1833 | \& { |
|
|
1834 | \& // set the relevant poll flags |
|
|
1835 | \& // could also call adns_processreadable etc. here |
|
|
1836 | \& struct pollfd *fd = fds + i; |
|
|
1837 | \& int revents = ev_clear_pending (iow + i); |
|
|
1838 | \& if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
|
|
1839 | \& if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
|
|
1840 | .Ve |
|
|
1841 | .PP |
|
|
1842 | .Vb 3 |
|
|
1843 | \& // now stop the watcher |
1701 | \& ev_io_stop (loop, iow + i); |
1844 | \& ev_io_stop (loop, iow + i); |
|
|
1845 | \& } |
1702 | .Ve |
1846 | .Ve |
1703 | .PP |
1847 | .PP |
1704 | .Vb 2 |
1848 | .Vb 2 |
1705 | \& adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
1849 | \& adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
|
|
1850 | \& } |
|
|
1851 | .Ve |
|
|
1852 | .PP |
|
|
1853 | Method 2: This would be just like method 1, but you run \f(CW\*(C`adns_afterpoll\*(C'\fR |
|
|
1854 | in the prepare watcher and would dispose of the check watcher. |
|
|
1855 | .PP |
|
|
1856 | Method 3: If the module to be embedded supports explicit event |
|
|
1857 | notification (adns does), you can also make use of the actual watcher |
|
|
1858 | callbacks, and only destroy/create the watchers in the prepare watcher. |
|
|
1859 | .PP |
|
|
1860 | .Vb 5 |
|
|
1861 | \& static void |
|
|
1862 | \& timer_cb (EV_P_ ev_timer *w, int revents) |
|
|
1863 | \& { |
|
|
1864 | \& adns_state ads = (adns_state)w->data; |
|
|
1865 | \& update_now (EV_A); |
|
|
1866 | .Ve |
|
|
1867 | .PP |
|
|
1868 | .Vb 2 |
|
|
1869 | \& adns_processtimeouts (ads, &tv_now); |
|
|
1870 | \& } |
|
|
1871 | .Ve |
|
|
1872 | .PP |
|
|
1873 | .Vb 5 |
|
|
1874 | \& static void |
|
|
1875 | \& io_cb (EV_P_ ev_io *w, int revents) |
|
|
1876 | \& { |
|
|
1877 | \& adns_state ads = (adns_state)w->data; |
|
|
1878 | \& update_now (EV_A); |
|
|
1879 | .Ve |
|
|
1880 | .PP |
|
|
1881 | .Vb 3 |
|
|
1882 | \& if (revents & EV_READ ) adns_processreadable (ads, w->fd, &tv_now); |
|
|
1883 | \& if (revents & EV_WRITE) adns_processwriteable (ads, w->fd, &tv_now); |
|
|
1884 | \& } |
|
|
1885 | .Ve |
|
|
1886 | .PP |
|
|
1887 | .Vb 1 |
|
|
1888 | \& // do not ever call adns_afterpoll |
|
|
1889 | .Ve |
|
|
1890 | .PP |
|
|
1891 | Method 4: Do not use a prepare or check watcher because the module you |
|
|
1892 | want to embed is too inflexible to support it. Instead, youc na override |
|
|
1893 | their poll function. The drawback with this solution is that the main |
|
|
1894 | loop is now no longer controllable by \s-1EV\s0. The \f(CW\*(C`Glib::EV\*(C'\fR module does |
|
|
1895 | this. |
|
|
1896 | .PP |
|
|
1897 | .Vb 4 |
|
|
1898 | \& static gint |
|
|
1899 | \& event_poll_func (GPollFD *fds, guint nfds, gint timeout) |
|
|
1900 | \& { |
|
|
1901 | \& int got_events = 0; |
|
|
1902 | .Ve |
|
|
1903 | .PP |
|
|
1904 | .Vb 2 |
|
|
1905 | \& for (n = 0; n < nfds; ++n) |
|
|
1906 | \& // create/start io watcher that sets the relevant bits in fds[n] and increment got_events |
|
|
1907 | .Ve |
|
|
1908 | .PP |
|
|
1909 | .Vb 2 |
|
|
1910 | \& if (timeout >= 0) |
|
|
1911 | \& // create/start timer |
|
|
1912 | .Ve |
|
|
1913 | .PP |
|
|
1914 | .Vb 2 |
|
|
1915 | \& // poll |
|
|
1916 | \& ev_loop (EV_A_ 0); |
|
|
1917 | .Ve |
|
|
1918 | .PP |
|
|
1919 | .Vb 3 |
|
|
1920 | \& // stop timer again |
|
|
1921 | \& if (timeout >= 0) |
|
|
1922 | \& ev_timer_stop (EV_A_ &to); |
|
|
1923 | .Ve |
|
|
1924 | .PP |
|
|
1925 | .Vb 3 |
|
|
1926 | \& // stop io watchers again - their callbacks should have set |
|
|
1927 | \& for (n = 0; n < nfds; ++n) |
|
|
1928 | \& ev_io_stop (EV_A_ iow [n]); |
|
|
1929 | .Ve |
|
|
1930 | .PP |
|
|
1931 | .Vb 2 |
|
|
1932 | \& return got_events; |
1706 | \& } |
1933 | \& } |
1707 | .Ve |
1934 | .Ve |
1708 | .ie n .Sh """ev_embed"" \- when one backend isn't enough..." |
1935 | .ie n .Sh """ev_embed"" \- when one backend isn't enough..." |
1709 | .el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..." |
1936 | .el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..." |
1710 | .IX Subsection "ev_embed - when one backend isn't enough..." |
1937 | .IX Subsection "ev_embed - when one backend isn't enough..." |
1711 | This is a rather advanced watcher type that lets you embed one event loop |
1938 | This is a rather advanced watcher type that lets you embed one event loop |
1712 | into another (currently only \f(CW\*(C`ev_io\*(C'\fR events are supported in the embedded |
1939 | into another (currently only \f(CW\*(C`ev_io\*(C'\fR events are supported in the embedded |
1713 | loop, other types of watchers might be handled in a delayed or incorrect |
1940 | loop, other types of watchers might be handled in a delayed or incorrect |
1714 | fashion and must not be used). |
1941 | fashion and must not be used). (See portability notes, below). |
1715 | .PP |
1942 | .PP |
1716 | There are primarily two reasons you would want that: work around bugs and |
1943 | There are primarily two reasons you would want that: work around bugs and |
1717 | prioritise I/O. |
1944 | prioritise I/O. |
1718 | .PP |
1945 | .PP |
1719 | As an example for a bug workaround, the kqueue backend might only support |
1946 | As an example for a bug workaround, the kqueue backend might only support |
… | |
… | |
1779 | \& ev_embed_start (loop_hi, &embed); |
2006 | \& ev_embed_start (loop_hi, &embed); |
1780 | \& } |
2007 | \& } |
1781 | \& else |
2008 | \& else |
1782 | \& loop_lo = loop_hi; |
2009 | \& loop_lo = loop_hi; |
1783 | .Ve |
2010 | .Ve |
|
|
2011 | .Sh "Portability notes" |
|
|
2012 | .IX Subsection "Portability notes" |
|
|
2013 | Kqueue is nominally embeddable, but this is broken on all BSDs that I |
|
|
2014 | tried, in various ways. Usually the embedded event loop will simply never |
|
|
2015 | receive events, sometimes it will only trigger a few times, sometimes in a |
|
|
2016 | loop. Epoll is also nominally embeddable, but many Linux kernel versions |
|
|
2017 | will always eport the epoll fd as ready, even when no events are pending. |
|
|
2018 | .PP |
|
|
2019 | While libev allows embedding these backends (they are contained in |
|
|
2020 | \&\f(CW\*(C`ev_embeddable_backends ()\*(C'\fR), take extreme care that it will actually |
|
|
2021 | work. |
|
|
2022 | .PP |
|
|
2023 | When in doubt, create a dynamic event loop forced to use sockets (this |
|
|
2024 | usually works) and possibly another thread and a pipe or so to report to |
|
|
2025 | your main event loop. |
|
|
2026 | .PP |
|
|
2027 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
2028 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1784 | .IP "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
2029 | .IP "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
1785 | .IX Item "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" |
2030 | .IX Item "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" |
1786 | .PD 0 |
2031 | .PD 0 |
1787 | .IP "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
2032 | .IP "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
1788 | .IX Item "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" |
2033 | .IX Item "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" |
… | |
… | |
1795 | .IP "ev_embed_sweep (loop, ev_embed *)" 4 |
2040 | .IP "ev_embed_sweep (loop, ev_embed *)" 4 |
1796 | .IX Item "ev_embed_sweep (loop, ev_embed *)" |
2041 | .IX Item "ev_embed_sweep (loop, ev_embed *)" |
1797 | Make a single, non-blocking sweep over the embedded loop. This works |
2042 | Make a single, non-blocking sweep over the embedded loop. This works |
1798 | similarly to \f(CW\*(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\*(C'\fR, but in the most |
2043 | similarly to \f(CW\*(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\*(C'\fR, but in the most |
1799 | apropriate way for embedded loops. |
2044 | apropriate way for embedded loops. |
1800 | .IP "struct ev_loop *loop [read\-only]" 4 |
2045 | .IP "struct ev_loop *other [read\-only]" 4 |
1801 | .IX Item "struct ev_loop *loop [read-only]" |
2046 | .IX Item "struct ev_loop *other [read-only]" |
1802 | The embedded event loop. |
2047 | The embedded event loop. |
1803 | .ie n .Sh """ev_fork"" \- the audacity to resume the event loop after a fork" |
2048 | .ie n .Sh """ev_fork"" \- the audacity to resume the event loop after a fork" |
1804 | .el .Sh "\f(CWev_fork\fP \- the audacity to resume the event loop after a fork" |
2049 | .el .Sh "\f(CWev_fork\fP \- the audacity to resume the event loop after a fork" |
1805 | .IX Subsection "ev_fork - the audacity to resume the event loop after a fork" |
2050 | .IX Subsection "ev_fork - the audacity to resume the event loop after a fork" |
1806 | Fork watchers are called when a \f(CW\*(C`fork ()\*(C'\fR was detected (usually because |
2051 | Fork watchers are called when a \f(CW\*(C`fork ()\*(C'\fR was detected (usually because |
… | |
… | |
1808 | \&\f(CW\*(C`ev_default_fork\*(C'\fR or \f(CW\*(C`ev_loop_fork\*(C'\fR). The invocation is done before the |
2053 | \&\f(CW\*(C`ev_default_fork\*(C'\fR or \f(CW\*(C`ev_loop_fork\*(C'\fR). The invocation is done before the |
1809 | event loop blocks next and before \f(CW\*(C`ev_check\*(C'\fR watchers are being called, |
2054 | event loop blocks next and before \f(CW\*(C`ev_check\*(C'\fR watchers are being called, |
1810 | and only in the child after the fork. If whoever good citizen calling |
2055 | and only in the child after the fork. If whoever good citizen calling |
1811 | \&\f(CW\*(C`ev_default_fork\*(C'\fR cheats and calls it in the wrong process, the fork |
2056 | \&\f(CW\*(C`ev_default_fork\*(C'\fR cheats and calls it in the wrong process, the fork |
1812 | handlers will be invoked, too, of course. |
2057 | handlers will be invoked, too, of course. |
|
|
2058 | .PP |
|
|
2059 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
2060 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1813 | .IP "ev_fork_init (ev_signal *, callback)" 4 |
2061 | .IP "ev_fork_init (ev_signal *, callback)" 4 |
1814 | .IX Item "ev_fork_init (ev_signal *, callback)" |
2062 | .IX Item "ev_fork_init (ev_signal *, callback)" |
1815 | Initialises and configures the fork watcher \- it has no parameters of any |
2063 | Initialises and configures the fork watcher \- it has no parameters of any |
1816 | kind. There is a \f(CW\*(C`ev_fork_set\*(C'\fR macro, but using it is utterly pointless, |
2064 | kind. There is a \f(CW\*(C`ev_fork_set\*(C'\fR macro, but using it is utterly pointless, |
1817 | believe me. |
2065 | believe me. |
… | |
… | |
1899 | This automatically includes \fIev.h\fR and puts all of its definitions (many |
2147 | This automatically includes \fIev.h\fR and puts all of its definitions (many |
1900 | of them macros) into the global namespace. All \*(C+ specific things are |
2148 | of them macros) into the global namespace. All \*(C+ specific things are |
1901 | put into the \f(CW\*(C`ev\*(C'\fR namespace. It should support all the same embedding |
2149 | put into the \f(CW\*(C`ev\*(C'\fR namespace. It should support all the same embedding |
1902 | options as \fIev.h\fR, most notably \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. |
2150 | options as \fIev.h\fR, most notably \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. |
1903 | .PP |
2151 | .PP |
1904 | Care has been taken to keep the overhead low. The only data member added |
2152 | Care has been taken to keep the overhead low. The only data member the \*(C+ |
1905 | to the C\-style watchers is the event loop the watcher is associated with |
2153 | classes add (compared to plain C\-style watchers) is the event loop pointer |
1906 | (or no additional members at all if you disable \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR when |
2154 | that the watcher is associated with (or no additional members at all if |
1907 | embedding libev). |
2155 | you disable \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR when embedding libev). |
1908 | .PP |
2156 | .PP |
1909 | Currently, functions and static and non-static member functions can be |
2157 | Currently, functions, and static and non-static member functions can be |
1910 | used as callbacks. Other types should be easy to add as long as they only |
2158 | used as callbacks. Other types should be easy to add as long as they only |
1911 | need one additional pointer for context. If you need support for other |
2159 | need one additional pointer for context. If you need support for other |
1912 | types of functors please contact the author (preferably after implementing |
2160 | types of functors please contact the author (preferably after implementing |
1913 | it). |
2161 | it). |
1914 | .PP |
2162 | .PP |
… | |
… | |
1978 | .Vb 3 |
2226 | .Vb 3 |
1979 | \& myclass obj; |
2227 | \& myclass obj; |
1980 | \& ev::io iow; |
2228 | \& ev::io iow; |
1981 | \& iow.set <myclass, &myclass::io_cb> (&obj); |
2229 | \& iow.set <myclass, &myclass::io_cb> (&obj); |
1982 | .Ve |
2230 | .Ve |
1983 | .IP "w\->set (void (*function)(watcher &w, int), void *data = 0)" 4 |
2231 | .IP "w\->set<function> (void *data = 0)" 4 |
1984 | .IX Item "w->set (void (*function)(watcher &w, int), void *data = 0)" |
2232 | .IX Item "w->set<function> (void *data = 0)" |
1985 | Also sets a callback, but uses a static method or plain function as |
2233 | Also sets a callback, but uses a static method or plain function as |
1986 | callback. The optional \f(CW\*(C`data\*(C'\fR argument will be stored in the watcher's |
2234 | callback. The optional \f(CW\*(C`data\*(C'\fR argument will be stored in the watcher's |
1987 | \&\f(CW\*(C`data\*(C'\fR member and is free for you to use. |
2235 | \&\f(CW\*(C`data\*(C'\fR member and is free for you to use. |
1988 | .Sp |
2236 | .Sp |
|
|
2237 | The prototype of the \f(CW\*(C`function\*(C'\fR must be \f(CW\*(C`void (*)(ev::TYPE &w, int)\*(C'\fR. |
|
|
2238 | .Sp |
1989 | See the method\-\f(CW\*(C`set\*(C'\fR above for more details. |
2239 | See the method\-\f(CW\*(C`set\*(C'\fR above for more details. |
|
|
2240 | .Sp |
|
|
2241 | Example: |
|
|
2242 | .Sp |
|
|
2243 | .Vb 2 |
|
|
2244 | \& static void io_cb (ev::io &w, int revents) { } |
|
|
2245 | \& iow.set <io_cb> (); |
|
|
2246 | .Ve |
1990 | .IP "w\->set (struct ev_loop *)" 4 |
2247 | .IP "w\->set (struct ev_loop *)" 4 |
1991 | .IX Item "w->set (struct ev_loop *)" |
2248 | .IX Item "w->set (struct ev_loop *)" |
1992 | Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only |
2249 | Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only |
1993 | do this when the watcher is inactive (and not pending either). |
2250 | do this when the watcher is inactive (and not pending either). |
1994 | .IP "w\->set ([args])" 4 |
2251 | .IP "w\->set ([args])" 4 |
… | |
… | |
2002 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument, as the |
2259 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument, as the |
2003 | constructor already stores the event loop. |
2260 | constructor already stores the event loop. |
2004 | .IP "w\->stop ()" 4 |
2261 | .IP "w\->stop ()" 4 |
2005 | .IX Item "w->stop ()" |
2262 | .IX Item "w->stop ()" |
2006 | Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument. |
2263 | Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument. |
2007 | .ie n .IP "w\->again () ""ev::timer""\fR, \f(CW""ev::periodic"" only" 4 |
2264 | .ie n .IP "w\->again () (""ev::timer""\fR, \f(CW""ev::periodic"" only)" 4 |
2008 | .el .IP "w\->again () \f(CWev::timer\fR, \f(CWev::periodic\fR only" 4 |
2265 | .el .IP "w\->again () (\f(CWev::timer\fR, \f(CWev::periodic\fR only)" 4 |
2009 | .IX Item "w->again () ev::timer, ev::periodic only" |
2266 | .IX Item "w->again () (ev::timer, ev::periodic only)" |
2010 | For \f(CW\*(C`ev::timer\*(C'\fR and \f(CW\*(C`ev::periodic\*(C'\fR, this invokes the corresponding |
2267 | For \f(CW\*(C`ev::timer\*(C'\fR and \f(CW\*(C`ev::periodic\*(C'\fR, this invokes the corresponding |
2011 | \&\f(CW\*(C`ev_TYPE_again\*(C'\fR function. |
2268 | \&\f(CW\*(C`ev_TYPE_again\*(C'\fR function. |
2012 | .ie n .IP "w\->sweep () ""ev::embed"" only" 4 |
2269 | .ie n .IP "w\->sweep () (""ev::embed"" only)" 4 |
2013 | .el .IP "w\->sweep () \f(CWev::embed\fR only" 4 |
2270 | .el .IP "w\->sweep () (\f(CWev::embed\fR only)" 4 |
2014 | .IX Item "w->sweep () ev::embed only" |
2271 | .IX Item "w->sweep () (ev::embed only)" |
2015 | Invokes \f(CW\*(C`ev_embed_sweep\*(C'\fR. |
2272 | Invokes \f(CW\*(C`ev_embed_sweep\*(C'\fR. |
2016 | .ie n .IP "w\->update () ""ev::stat"" only" 4 |
2273 | .ie n .IP "w\->update () (""ev::stat"" only)" 4 |
2017 | .el .IP "w\->update () \f(CWev::stat\fR only" 4 |
2274 | .el .IP "w\->update () (\f(CWev::stat\fR only)" 4 |
2018 | .IX Item "w->update () ev::stat only" |
2275 | .IX Item "w->update () (ev::stat only)" |
2019 | Invokes \f(CW\*(C`ev_stat_stat\*(C'\fR. |
2276 | Invokes \f(CW\*(C`ev_stat_stat\*(C'\fR. |
2020 | .RE |
2277 | .RE |
2021 | .RS 4 |
2278 | .RS 4 |
2022 | .RE |
2279 | .RE |
2023 | .PP |
2280 | .PP |
… | |
… | |
2047 | \& io.start (fd, ev::READ); |
2304 | \& io.start (fd, ev::READ); |
2048 | \& } |
2305 | \& } |
2049 | .Ve |
2306 | .Ve |
2050 | .SH "MACRO MAGIC" |
2307 | .SH "MACRO MAGIC" |
2051 | .IX Header "MACRO MAGIC" |
2308 | .IX Header "MACRO MAGIC" |
2052 | Libev can be compiled with a variety of options, the most fundemantal is |
2309 | Libev can be compiled with a variety of options, the most fundamantal |
2053 | \&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines whether (most) functions and |
2310 | of which is \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines whether (most) |
2054 | callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument. |
2311 | functions and callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument. |
2055 | .PP |
2312 | .PP |
2056 | To make it easier to write programs that cope with either variant, the |
2313 | To make it easier to write programs that cope with either variant, the |
2057 | following macros are defined: |
2314 | following macros are defined: |
2058 | .ie n .IP """EV_A""\fR, \f(CW""EV_A_""" 4 |
2315 | .ie n .IP """EV_A""\fR, \f(CW""EV_A_""" 4 |
2059 | .el .IP "\f(CWEV_A\fR, \f(CWEV_A_\fR" 4 |
2316 | .el .IP "\f(CWEV_A\fR, \f(CWEV_A_\fR" 4 |
… | |
… | |
2118 | Libev can (and often is) directly embedded into host |
2375 | Libev can (and often is) directly embedded into host |
2119 | applications. Examples of applications that embed it include the Deliantra |
2376 | applications. Examples of applications that embed it include the Deliantra |
2120 | Game Server, the \s-1EV\s0 perl module, the \s-1GNU\s0 Virtual Private Ethernet (gvpe) |
2377 | Game Server, the \s-1EV\s0 perl module, the \s-1GNU\s0 Virtual Private Ethernet (gvpe) |
2121 | and rxvt\-unicode. |
2378 | and rxvt\-unicode. |
2122 | .PP |
2379 | .PP |
2123 | The goal is to enable you to just copy the neecssary files into your |
2380 | The goal is to enable you to just copy the necessary files into your |
2124 | source directory without having to change even a single line in them, so |
2381 | source directory without having to change even a single line in them, so |
2125 | you can easily upgrade by simply copying (or having a checked-out copy of |
2382 | you can easily upgrade by simply copying (or having a checked-out copy of |
2126 | libev somewhere in your source tree). |
2383 | libev somewhere in your source tree). |
2127 | .Sh "\s-1FILESETS\s0" |
2384 | .Sh "\s-1FILESETS\s0" |
2128 | .IX Subsection "FILESETS" |
2385 | .IX Subsection "FILESETS" |
… | |
… | |
2233 | .IX Item "EV_USE_MONOTONIC" |
2490 | .IX Item "EV_USE_MONOTONIC" |
2234 | If defined to be \f(CW1\fR, libev will try to detect the availability of the |
2491 | If defined to be \f(CW1\fR, libev will try to detect the availability of the |
2235 | monotonic clock option at both compiletime and runtime. Otherwise no use |
2492 | monotonic clock option at both compiletime and runtime. Otherwise no use |
2236 | of the monotonic clock option will be attempted. If you enable this, you |
2493 | of the monotonic clock option will be attempted. If you enable this, you |
2237 | usually have to link against librt or something similar. Enabling it when |
2494 | usually have to link against librt or something similar. Enabling it when |
2238 | the functionality isn't available is safe, though, althoguh you have |
2495 | the functionality isn't available is safe, though, although you have |
2239 | to make sure you link against any libraries where the \f(CW\*(C`clock_gettime\*(C'\fR |
2496 | to make sure you link against any libraries where the \f(CW\*(C`clock_gettime\*(C'\fR |
2240 | function is hiding in (often \fI\-lrt\fR). |
2497 | function is hiding in (often \fI\-lrt\fR). |
2241 | .IP "\s-1EV_USE_REALTIME\s0" 4 |
2498 | .IP "\s-1EV_USE_REALTIME\s0" 4 |
2242 | .IX Item "EV_USE_REALTIME" |
2499 | .IX Item "EV_USE_REALTIME" |
2243 | If defined to be \f(CW1\fR, libev will try to detect the availability of the |
2500 | If defined to be \f(CW1\fR, libev will try to detect the availability of the |
2244 | realtime clock option at compiletime (and assume its availability at |
2501 | realtime clock option at compiletime (and assume its availability at |
2245 | runtime if successful). Otherwise no use of the realtime clock option will |
2502 | runtime if successful). Otherwise no use of the realtime clock option will |
2246 | be attempted. This effectively replaces \f(CW\*(C`gettimeofday\*(C'\fR by \f(CW\*(C`clock_get |
2503 | be attempted. This effectively replaces \f(CW\*(C`gettimeofday\*(C'\fR by \f(CW\*(C`clock_get |
2247 | (CLOCK_REALTIME, ...)\*(C'\fR and will not normally affect correctness. See tzhe note about libraries |
2504 | (CLOCK_REALTIME, ...)\*(C'\fR and will not normally affect correctness. See the |
2248 | in the description of \f(CW\*(C`EV_USE_MONOTONIC\*(C'\fR, though. |
2505 | note about libraries in the description of \f(CW\*(C`EV_USE_MONOTONIC\*(C'\fR, though. |
2249 | .IP "\s-1EV_USE_SELECT\s0" 4 |
2506 | .IP "\s-1EV_USE_SELECT\s0" 4 |
2250 | .IX Item "EV_USE_SELECT" |
2507 | .IX Item "EV_USE_SELECT" |
2251 | If undefined or defined to be \f(CW1\fR, libev will compile in support for the |
2508 | If undefined or defined to be \f(CW1\fR, libev will compile in support for the |
2252 | \&\f(CW\*(C`select\*(C'\fR(2) backend. No attempt at autodetection will be done: if no |
2509 | \&\f(CW\*(C`select\*(C'\fR(2) backend. No attempt at autodetection will be done: if no |
2253 | other method takes over, select will be it. Otherwise the select backend |
2510 | other method takes over, select will be it. Otherwise the select backend |
… | |
… | |
2413 | .IP "ev_set_cb (ev, cb)" 4 |
2670 | .IP "ev_set_cb (ev, cb)" 4 |
2414 | .IX Item "ev_set_cb (ev, cb)" |
2671 | .IX Item "ev_set_cb (ev, cb)" |
2415 | .PD |
2672 | .PD |
2416 | Can be used to change the callback member declaration in each watcher, |
2673 | Can be used to change the callback member declaration in each watcher, |
2417 | and the way callbacks are invoked and set. Must expand to a struct member |
2674 | and the way callbacks are invoked and set. Must expand to a struct member |
2418 | definition and a statement, respectively. See the \fIev.v\fR header file for |
2675 | definition and a statement, respectively. See the \fIev.h\fR header file for |
2419 | their default definitions. One possible use for overriding these is to |
2676 | their default definitions. One possible use for overriding these is to |
2420 | avoid the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument in all cases, or to use |
2677 | avoid the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument in all cases, or to use |
2421 | method calls instead of plain function calls in \*(C+. |
2678 | method calls instead of plain function calls in \*(C+. |
|
|
2679 | .Sh "\s-1EXPORTED\s0 \s-1API\s0 \s-1SYMBOLS\s0" |
|
|
2680 | .IX Subsection "EXPORTED API SYMBOLS" |
|
|
2681 | If you need to re-export the \s-1API\s0 (e.g. via a dll) and you need a list of |
|
|
2682 | exported symbols, you can use the provided \fISymbol.*\fR files which list |
|
|
2683 | all public symbols, one per line: |
|
|
2684 | .Sp |
|
|
2685 | .Vb 2 |
|
|
2686 | \& Symbols.ev for libev proper |
|
|
2687 | \& Symbols.event for the libevent emulation |
|
|
2688 | .Ve |
|
|
2689 | .Sp |
|
|
2690 | This can also be used to rename all public symbols to avoid clashes with |
|
|
2691 | multiple versions of libev linked together (which is obviously bad in |
|
|
2692 | itself, but sometimes it is inconvinient to avoid this). |
|
|
2693 | .Sp |
|
|
2694 | A sed command like this will create wrapper \f(CW\*(C`#define\*(C'\fR's that you need to |
|
|
2695 | include before including \fIev.h\fR: |
|
|
2696 | .Sp |
|
|
2697 | .Vb 1 |
|
|
2698 | \& <Symbols.ev sed -e "s/.*/#define & myprefix_&/" >wrap.h |
|
|
2699 | .Ve |
|
|
2700 | .Sp |
|
|
2701 | This would create a file \fIwrap.h\fR which essentially looks like this: |
|
|
2702 | .Sp |
|
|
2703 | .Vb 4 |
|
|
2704 | \& #define ev_backend myprefix_ev_backend |
|
|
2705 | \& #define ev_check_start myprefix_ev_check_start |
|
|
2706 | \& #define ev_check_stop myprefix_ev_check_stop |
|
|
2707 | \& ... |
|
|
2708 | .Ve |
2422 | .Sh "\s-1EXAMPLES\s0" |
2709 | .Sh "\s-1EXAMPLES\s0" |
2423 | .IX Subsection "EXAMPLES" |
2710 | .IX Subsection "EXAMPLES" |
2424 | For a real-world example of a program the includes libev |
2711 | For a real-world example of a program the includes libev |
2425 | verbatim, you can have a look at the \s-1EV\s0 perl module |
2712 | verbatim, you can have a look at the \s-1EV\s0 perl module |
2426 | (<http://software.schmorp.de/pkg/EV.html>). It has the libev files in |
2713 | (<http://software.schmorp.de/pkg/EV.html>). It has the libev files in |