… | |
… | |
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 "2007-12-09" "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. |
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260 | .IP "ev_sleep (ev_tstamp interval)" 4 |
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261 | .IX Item "ev_sleep (ev_tstamp interval)" |
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262 | Sleep for the given interval: The current thread will be blocked until |
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263 | either it is interrupted or the given time interval has passed. Basically |
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264 | this is a subsecond-resolution \f(CW\*(C`sleep ()\*(C'\fR. |
258 | .IP "int ev_version_major ()" 4 |
265 | .IP "int ev_version_major ()" 4 |
259 | .IX Item "int ev_version_major ()" |
266 | .IX Item "int ev_version_major ()" |
260 | .PD 0 |
267 | .PD 0 |
261 | .IP "int ev_version_minor ()" 4 |
268 | .IP "int ev_version_minor ()" 4 |
262 | .IX Item "int ev_version_minor ()" |
269 | .IX Item "int ev_version_minor ()" |
… | |
… | |
444 | .el .IP "\f(CWEVBACKEND_SELECT\fR (value 1, portable select backend)" 4 |
451 | .el .IP "\f(CWEVBACKEND_SELECT\fR (value 1, portable select backend)" 4 |
445 | .IX Item "EVBACKEND_SELECT (value 1, portable select backend)" |
452 | .IX Item "EVBACKEND_SELECT (value 1, portable select backend)" |
446 | This is your standard \fIselect\fR\|(2) backend. Not \fIcompletely\fR standard, as |
453 | This is your standard \fIselect\fR\|(2) backend. Not \fIcompletely\fR standard, as |
447 | libev tries to roll its own fd_set with no limits on the number of fds, |
454 | libev tries to roll its own fd_set with no limits on the number of fds, |
448 | but if that fails, expect a fairly low limit on the number of fds when |
455 | but if that fails, expect a fairly low limit on the number of fds when |
449 | using this backend. It doesn't scale too well (O(highest_fd)), but its usually |
456 | using this backend. It doesn't scale too well (O(highest_fd)), but its |
450 | the fastest backend for a low number of fds. |
457 | usually the fastest backend for a low number of (low\-numbered :) fds. |
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458 | .Sp |
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459 | To get good performance out of this backend you need a high amount of |
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460 | parallelity (most of the file descriptors should be busy). If you are |
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461 | writing a server, you should \f(CW\*(C`accept ()\*(C'\fR in a loop to accept as many |
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462 | connections as possible during one iteration. You might also want to have |
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463 | a look at \f(CW\*(C`ev_set_io_collect_interval ()\*(C'\fR to increase the amount of |
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464 | readyness notifications you get per iteration. |
451 | .ie n .IP """EVBACKEND_POLL"" (value 2, poll backend, available everywhere except on windows)" 4 |
465 | .ie n .IP """EVBACKEND_POLL"" (value 2, poll backend, available everywhere except on windows)" 4 |
452 | .el .IP "\f(CWEVBACKEND_POLL\fR (value 2, poll backend, available everywhere except on windows)" 4 |
466 | .el .IP "\f(CWEVBACKEND_POLL\fR (value 2, poll backend, available everywhere except on windows)" 4 |
453 | .IX Item "EVBACKEND_POLL (value 2, poll backend, available everywhere except on windows)" |
467 | .IX Item "EVBACKEND_POLL (value 2, poll backend, available everywhere except on windows)" |
454 | And this is your standard \fIpoll\fR\|(2) backend. It's more complicated than |
468 | And this is your standard \fIpoll\fR\|(2) backend. It's more complicated |
455 | select, but handles sparse fds better and has no artificial limit on the |
469 | than select, but handles sparse fds better and has no artificial |
456 | number of fds you can use (except it will slow down considerably with a |
470 | limit on the number of fds you can use (except it will slow down |
457 | lot of inactive fds). It scales similarly to select, i.e. O(total_fds). |
471 | considerably with a lot of inactive fds). It scales similarly to select, |
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472 | i.e. O(total_fds). See the entry for \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR, above, for |
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473 | performance tips. |
458 | .ie n .IP """EVBACKEND_EPOLL"" (value 4, Linux)" 4 |
474 | .ie n .IP """EVBACKEND_EPOLL"" (value 4, Linux)" 4 |
459 | .el .IP "\f(CWEVBACKEND_EPOLL\fR (value 4, Linux)" 4 |
475 | .el .IP "\f(CWEVBACKEND_EPOLL\fR (value 4, Linux)" 4 |
460 | .IX Item "EVBACKEND_EPOLL (value 4, Linux)" |
476 | .IX Item "EVBACKEND_EPOLL (value 4, Linux)" |
461 | For few fds, this backend is a bit little slower than poll and select, |
477 | For few fds, this backend is a bit little slower than poll and select, |
462 | but it scales phenomenally better. While poll and select usually scale like |
478 | 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 |
479 | like O(total_fds) where n is the total number of fds (or the highest fd), |
464 | either O(1) or O(active_fds). |
480 | epoll scales either O(1) or O(active_fds). The epoll design has a number |
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481 | of shortcomings, such as silently dropping events in some hard-to-detect |
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482 | cases and rewiring a syscall per fd change, no fork support and bad |
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483 | support for dup. |
465 | .Sp |
484 | .Sp |
466 | While stopping and starting an I/O watcher in the same iteration will |
485 | While stopping, setting and starting an I/O watcher in the same iteration |
467 | result in some caching, there is still a syscall per such incident |
486 | will result in some caching, there is still a syscall per such incident |
468 | (because the fd could point to a different file description now), so its |
487 | (because the fd could point to a different file description now), so its |
469 | best to avoid that. Also, \fIdup()\fRed file descriptors might not work very |
488 | best to avoid that. Also, \f(CW\*(C`dup ()\*(C'\fR'ed file descriptors might not work |
470 | well if you register events for both fds. |
489 | very well if you register events for both fds. |
471 | .Sp |
490 | .Sp |
472 | Please note that epoll sometimes generates spurious notifications, so you |
491 | 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 |
492 | need to use non-blocking I/O or other means to avoid blocking when no data |
474 | (or space) is available. |
493 | (or space) is available. |
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494 | .Sp |
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495 | Best performance from this backend is achieved by not unregistering all |
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496 | watchers for a file descriptor until it has been closed, if possible, i.e. |
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497 | keep at least one watcher active per fd at all times. |
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498 | .Sp |
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499 | While nominally embeddeble in other event loops, this feature is broken in |
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500 | all kernel versions tested so far. |
475 | .ie n .IP """EVBACKEND_KQUEUE"" (value 8, most \s-1BSD\s0 clones)" 4 |
501 | .ie n .IP """EVBACKEND_KQUEUE"" (value 8, most \s-1BSD\s0 clones)" 4 |
476 | .el .IP "\f(CWEVBACKEND_KQUEUE\fR (value 8, most \s-1BSD\s0 clones)" 4 |
502 | .el .IP "\f(CWEVBACKEND_KQUEUE\fR (value 8, most \s-1BSD\s0 clones)" 4 |
477 | .IX Item "EVBACKEND_KQUEUE (value 8, most BSD clones)" |
503 | .IX Item "EVBACKEND_KQUEUE (value 8, most BSD clones)" |
478 | Kqueue deserves special mention, as at the time of this writing, it |
504 | Kqueue deserves special mention, as at the time of this writing, it |
479 | was broken on all BSDs except NetBSD (usually it doesn't work with |
505 | was broken on all BSDs except NetBSD (usually it doesn't work reliably |
480 | anything but sockets and pipes, except on Darwin, where of course its |
506 | with anything but sockets and pipes, except on Darwin, where of course |
481 | completely useless). For this reason its not being \*(L"autodetected\*(R" |
507 | it's completely useless). For this reason it's not being \*(L"autodetected\*(R" |
482 | unless you explicitly specify it explicitly in the flags (i.e. using |
508 | unless you explicitly specify it explicitly in the flags (i.e. using |
483 | \&\f(CW\*(C`EVBACKEND_KQUEUE\*(C'\fR). |
509 | \&\f(CW\*(C`EVBACKEND_KQUEUE\*(C'\fR) or libev was compiled on a known-to-be-good (\-enough) |
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510 | system like NetBSD. |
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511 | .Sp |
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512 | You still can embed kqueue into a normal poll or select backend and use it |
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513 | only for sockets (after having made sure that sockets work with kqueue on |
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514 | the target platform). See \f(CW\*(C`ev_embed\*(C'\fR watchers for more info. |
484 | .Sp |
515 | .Sp |
485 | It scales in the same way as the epoll backend, but the interface to the |
516 | It scales in the same way as the epoll backend, but the interface to the |
486 | kernel is more efficient (which says nothing about its actual speed, of |
517 | kernel is more efficient (which says nothing about its actual speed, of |
487 | course). While starting and stopping an I/O watcher does not cause an |
518 | course). While stopping, setting and starting an I/O watcher does never |
488 | extra syscall as with epoll, it still adds up to four event changes per |
519 | cause an extra syscall as with \f(CW\*(C`EVBACKEND_EPOLL\*(C'\fR, it still adds up to |
489 | incident, so its best to avoid that. |
520 | two event changes per incident, support for \f(CW\*(C`fork ()\*(C'\fR is very bad and it |
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521 | drops fds silently in similarly hard-to-detect cases. |
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522 | .Sp |
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523 | This backend usually performs well under most conditions. |
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524 | .Sp |
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525 | While nominally embeddable in other event loops, this doesn't work |
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526 | everywhere, so you might need to test for this. And since it is broken |
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527 | almost everywhere, you should only use it when you have a lot of sockets |
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528 | (for which it usually works), by embedding it into another event loop |
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529 | (e.g. \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR or \f(CW\*(C`EVBACKEND_POLL\*(C'\fR) and using it only for |
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530 | sockets. |
490 | .ie n .IP """EVBACKEND_DEVPOLL"" (value 16, Solaris 8)" 4 |
531 | .ie n .IP """EVBACKEND_DEVPOLL"" (value 16, Solaris 8)" 4 |
491 | .el .IP "\f(CWEVBACKEND_DEVPOLL\fR (value 16, Solaris 8)" 4 |
532 | .el .IP "\f(CWEVBACKEND_DEVPOLL\fR (value 16, Solaris 8)" 4 |
492 | .IX Item "EVBACKEND_DEVPOLL (value 16, Solaris 8)" |
533 | .IX Item "EVBACKEND_DEVPOLL (value 16, Solaris 8)" |
493 | This is not implemented yet (and might never be). |
534 | This is not implemented yet (and might never be, unless you send me an |
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535 | implementation). According to reports, \f(CW\*(C`/dev/poll\*(C'\fR only supports sockets |
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536 | and is not embeddable, which would limit the usefulness of this backend |
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537 | immensely. |
494 | .ie n .IP """EVBACKEND_PORT"" (value 32, Solaris 10)" 4 |
538 | .ie n .IP """EVBACKEND_PORT"" (value 32, Solaris 10)" 4 |
495 | .el .IP "\f(CWEVBACKEND_PORT\fR (value 32, Solaris 10)" 4 |
539 | .el .IP "\f(CWEVBACKEND_PORT\fR (value 32, Solaris 10)" 4 |
496 | .IX Item "EVBACKEND_PORT (value 32, Solaris 10)" |
540 | .IX Item "EVBACKEND_PORT (value 32, Solaris 10)" |
497 | This uses the Solaris 10 port mechanism. As with everything on Solaris, |
541 | This uses the Solaris 10 event port mechanism. As with everything on Solaris, |
498 | it's really slow, but it still scales very well (O(active_fds)). |
542 | it's really slow, but it still scales very well (O(active_fds)). |
499 | .Sp |
543 | .Sp |
500 | Please note that solaris ports can result in a lot of spurious |
544 | Please note that solaris event ports can deliver a lot of spurious |
501 | notifications, so you need to use non-blocking I/O or other means to avoid |
545 | notifications, so you need to use non-blocking I/O or other means to avoid |
502 | blocking when no data (or space) is available. |
546 | blocking when no data (or space) is available. |
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547 | .Sp |
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548 | While this backend scales well, it requires one system call per active |
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549 | file descriptor per loop iteration. For small and medium numbers of file |
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550 | descriptors a \*(L"slow\*(R" \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR or \f(CW\*(C`EVBACKEND_POLL\*(C'\fR backend |
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551 | might perform better. |
503 | .ie n .IP """EVBACKEND_ALL""" 4 |
552 | .ie n .IP """EVBACKEND_ALL""" 4 |
504 | .el .IP "\f(CWEVBACKEND_ALL\fR" 4 |
553 | .el .IP "\f(CWEVBACKEND_ALL\fR" 4 |
505 | .IX Item "EVBACKEND_ALL" |
554 | .IX Item "EVBACKEND_ALL" |
506 | Try all backends (even potentially broken ones that wouldn't be tried |
555 | Try all backends (even potentially broken ones that wouldn't be tried |
507 | with \f(CW\*(C`EVFLAG_AUTO\*(C'\fR). Since this is a mask, you can do stuff such as |
556 | with \f(CW\*(C`EVFLAG_AUTO\*(C'\fR). Since this is a mask, you can do stuff such as |
508 | \&\f(CW\*(C`EVBACKEND_ALL & ~EVBACKEND_KQUEUE\*(C'\fR. |
557 | \&\f(CW\*(C`EVBACKEND_ALL & ~EVBACKEND_KQUEUE\*(C'\fR. |
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558 | .Sp |
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559 | It is definitely not recommended to use this flag. |
509 | .RE |
560 | .RE |
510 | .RS 4 |
561 | .RS 4 |
511 | .Sp |
562 | .Sp |
512 | If one or more of these are ored into the flags value, then only these |
563 | If one or more of these are ored into the flags value, then only these |
513 | backends will be tried (in the reverse order as given here). If none are |
564 | backends will be tried (in the reverse order as given here). If none are |
… | |
… | |
555 | Destroys the default loop again (frees all memory and kernel state |
606 | 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 |
607 | 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 |
608 | 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 |
609 | responsibility to either stop all watchers cleanly yoursef \fIbefore\fR |
559 | calling this function, or cope with the fact afterwards (which is usually |
610 | calling this function, or cope with the fact afterwards (which is usually |
560 | the easiest thing, youc na just ignore the watchers and/or \f(CW\*(C`free ()\*(C'\fR them |
611 | the easiest thing, you can just ignore the watchers and/or \f(CW\*(C`free ()\*(C'\fR them |
561 | for example). |
612 | for example). |
|
|
613 | .Sp |
|
|
614 | Note that certain global state, such as signal state, will not be freed by |
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615 | this function, and related watchers (such as signal and child watchers) |
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616 | would need to be stopped manually. |
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617 | .Sp |
|
|
618 | In general it is not advisable to call this function except in the |
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619 | rare occasion where you really need to free e.g. the signal handling |
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|
620 | pipe fds. If you need dynamically allocated loops it is better to use |
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|
621 | \&\f(CW\*(C`ev_loop_new\*(C'\fR and \f(CW\*(C`ev_loop_destroy\*(C'\fR). |
562 | .IP "ev_loop_destroy (loop)" 4 |
622 | .IP "ev_loop_destroy (loop)" 4 |
563 | .IX Item "ev_loop_destroy (loop)" |
623 | .IX Item "ev_loop_destroy (loop)" |
564 | Like \f(CW\*(C`ev_default_destroy\*(C'\fR, but destroys an event loop created by an |
624 | Like \f(CW\*(C`ev_default_destroy\*(C'\fR, but destroys an event loop created by an |
565 | earlier call to \f(CW\*(C`ev_loop_new\*(C'\fR. |
625 | earlier call to \f(CW\*(C`ev_loop_new\*(C'\fR. |
566 | .IP "ev_default_fork ()" 4 |
626 | .IP "ev_default_fork ()" 4 |
… | |
… | |
607 | .IX Item "ev_tstamp ev_now (loop)" |
667 | .IX Item "ev_tstamp ev_now (loop)" |
608 | Returns the current \*(L"event loop time\*(R", which is the time the event loop |
668 | Returns the current \*(L"event loop time\*(R", which is the time the event loop |
609 | received events and started processing them. This timestamp does not |
669 | 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 |
670 | 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 |
671 | 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). |
672 | event occurring (or more correctly, libev finding out about it). |
613 | .IP "ev_loop (loop, int flags)" 4 |
673 | .IP "ev_loop (loop, int flags)" 4 |
614 | .IX Item "ev_loop (loop, int flags)" |
674 | .IX Item "ev_loop (loop, int flags)" |
615 | Finally, this is it, the event handler. This function usually is called |
675 | Finally, this is it, the event handler. This function usually is called |
616 | after you initialised all your watchers and you want to start handling |
676 | after you initialised all your watchers and you want to start handling |
617 | events. |
677 | events. |
… | |
… | |
707 | .Sp |
767 | .Sp |
708 | .Vb 2 |
768 | .Vb 2 |
709 | \& ev_ref (loop); |
769 | \& ev_ref (loop); |
710 | \& ev_signal_stop (loop, &exitsig); |
770 | \& ev_signal_stop (loop, &exitsig); |
711 | .Ve |
771 | .Ve |
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|
772 | .IP "ev_set_io_collect_interval (loop, ev_tstamp interval)" 4 |
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|
773 | .IX Item "ev_set_io_collect_interval (loop, ev_tstamp interval)" |
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|
774 | .PD 0 |
|
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775 | .IP "ev_set_timeout_collect_interval (loop, ev_tstamp interval)" 4 |
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|
776 | .IX Item "ev_set_timeout_collect_interval (loop, ev_tstamp interval)" |
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|
777 | .PD |
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778 | These advanced functions influence the time that libev will spend waiting |
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779 | for events. Both are by default \f(CW0\fR, meaning that libev will try to |
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780 | invoke timer/periodic callbacks and I/O callbacks with minimum latency. |
|
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781 | .Sp |
|
|
782 | Setting these to a higher value (the \f(CW\*(C`interval\*(C'\fR \fImust\fR be >= \f(CW0\fR) |
|
|
783 | allows libev to delay invocation of I/O and timer/periodic callbacks to |
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|
784 | increase efficiency of loop iterations. |
|
|
785 | .Sp |
|
|
786 | The background is that sometimes your program runs just fast enough to |
|
|
787 | handle one (or very few) event(s) per loop iteration. While this makes |
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|
788 | the program responsive, it also wastes a lot of \s-1CPU\s0 time to poll for new |
|
|
789 | events, especially with backends like \f(CW\*(C`select ()\*(C'\fR which have a high |
|
|
790 | overhead for the actual polling but can deliver many events at once. |
|
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791 | .Sp |
|
|
792 | By setting a higher \fIio collect interval\fR you allow libev to spend more |
|
|
793 | time collecting I/O events, so you can handle more events per iteration, |
|
|
794 | at the cost of increasing latency. Timeouts (both \f(CW\*(C`ev_periodic\*(C'\fR and |
|
|
795 | \&\f(CW\*(C`ev_timer\*(C'\fR) will be not affected. Setting this to a non-null value will |
|
|
796 | introduce an additional \f(CW\*(C`ev_sleep ()\*(C'\fR call into most loop iterations. |
|
|
797 | .Sp |
|
|
798 | Likewise, by setting a higher \fItimeout collect interval\fR you allow libev |
|
|
799 | to spend more time collecting timeouts, at the expense of increased |
|
|
800 | latency (the watcher callback will be called later). \f(CW\*(C`ev_io\*(C'\fR watchers |
|
|
801 | will not be affected. Setting this to a non-null value will not introduce |
|
|
802 | any overhead in libev. |
|
|
803 | .Sp |
|
|
804 | Many (busy) programs can usually benefit by setting the io collect |
|
|
805 | interval to a value near \f(CW0.1\fR or so, which is often enough for |
|
|
806 | interactive servers (of course not for games), likewise for timeouts. It |
|
|
807 | usually doesn't make much sense to set it to a lower value than \f(CW0.01\fR, |
|
|
808 | as this approsaches the timing granularity of most systems. |
712 | .SH "ANATOMY OF A WATCHER" |
809 | .SH "ANATOMY OF A WATCHER" |
713 | .IX Header "ANATOMY OF A WATCHER" |
810 | .IX Header "ANATOMY OF A WATCHER" |
714 | A watcher is a structure that you create and register to record your |
811 | A watcher is a structure that you create and register to record your |
715 | interest in some event. For instance, if you want to wait for \s-1STDIN\s0 to |
812 | interest in some event. For instance, if you want to wait for \s-1STDIN\s0 to |
716 | become readable, you would create an \f(CW\*(C`ev_io\*(C'\fR watcher for that: |
813 | become readable, you would create an \f(CW\*(C`ev_io\*(C'\fR watcher for that: |
… | |
… | |
1065 | If you cannot run the fd in non-blocking mode (for example you should not |
1162 | If you cannot run the fd in non-blocking mode (for example you should not |
1066 | play around with an Xlib connection), then you have to seperately re-test |
1163 | play around with an Xlib connection), then you have to seperately re-test |
1067 | whether a file descriptor is really ready with a known-to-be good interface |
1164 | whether a file descriptor is really ready with a known-to-be good interface |
1068 | such as poll (fortunately in our Xlib example, Xlib already does this on |
1165 | such as poll (fortunately in our Xlib example, Xlib already does this on |
1069 | its own, so its quite safe to use). |
1166 | its own, so its quite safe to use). |
|
|
1167 | .PP |
|
|
1168 | \fIThe special problem of disappearing file descriptors\fR |
|
|
1169 | .IX Subsection "The special problem of disappearing file descriptors" |
|
|
1170 | .PP |
|
|
1171 | Some backends (e.g. kqueue, epoll) need to be told about closing a file |
|
|
1172 | descriptor (either by calling \f(CW\*(C`close\*(C'\fR explicitly or by any other means, |
|
|
1173 | such as \f(CW\*(C`dup\*(C'\fR). The reason is that you register interest in some file |
|
|
1174 | descriptor, but when it goes away, the operating system will silently drop |
|
|
1175 | this interest. If another file descriptor with the same number then is |
|
|
1176 | registered with libev, there is no efficient way to see that this is, in |
|
|
1177 | fact, a different file descriptor. |
|
|
1178 | .PP |
|
|
1179 | To avoid having to explicitly tell libev about such cases, libev follows |
|
|
1180 | the following policy: Each time \f(CW\*(C`ev_io_set\*(C'\fR is being called, libev |
|
|
1181 | will assume that this is potentially a new file descriptor, otherwise |
|
|
1182 | it is assumed that the file descriptor stays the same. That means that |
|
|
1183 | 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 |
|
|
1184 | descriptor even if the file descriptor number itself did not change. |
|
|
1185 | .PP |
|
|
1186 | This is how one would do it normally anyway, the important point is that |
|
|
1187 | the libev application should not optimise around libev but should leave |
|
|
1188 | optimisations to libev. |
|
|
1189 | .PP |
|
|
1190 | \fIThe special problem of dup'ed file descriptors\fR |
|
|
1191 | .IX Subsection "The special problem of dup'ed file descriptors" |
|
|
1192 | .PP |
|
|
1193 | Some backends (e.g. epoll), cannot register events for file descriptors, |
|
|
1194 | but only events for the underlying file descriptions. That menas when you |
|
|
1195 | have \f(CW\*(C`dup ()\*(C'\fR'ed file descriptors and register events for them, only one |
|
|
1196 | file descriptor might actually receive events. |
|
|
1197 | .PP |
|
|
1198 | There is no workaorund possible except not registering events |
|
|
1199 | for potentially \f(CW\*(C`dup ()\*(C'\fR'ed file descriptors or to resort to |
|
|
1200 | \&\f(CW\*(C`EVBACKEND_SELECT\*(C'\fR or \f(CW\*(C`EVBACKEND_POLL\*(C'\fR. |
|
|
1201 | .PP |
|
|
1202 | \fIThe special problem of fork\fR |
|
|
1203 | .IX Subsection "The special problem of fork" |
|
|
1204 | .PP |
|
|
1205 | Some backends (epoll, kqueue) do not support \f(CW\*(C`fork ()\*(C'\fR at all or exhibit |
|
|
1206 | useless behaviour. Libev fully supports fork, but needs to be told about |
|
|
1207 | it in the child. |
|
|
1208 | .PP |
|
|
1209 | To support fork in your programs, you either have to call |
|
|
1210 | \&\f(CW\*(C`ev_default_fork ()\*(C'\fR or \f(CW\*(C`ev_loop_fork ()\*(C'\fR after a fork in the child, |
|
|
1211 | enable \f(CW\*(C`EVFLAG_FORKCHECK\*(C'\fR, or resort to \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR or |
|
|
1212 | \&\f(CW\*(C`EVBACKEND_POLL\*(C'\fR. |
|
|
1213 | .PP |
|
|
1214 | \fIWatcher-Specific Functions\fR |
|
|
1215 | .IX Subsection "Watcher-Specific Functions" |
1070 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
1216 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
1071 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
1217 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
1072 | .PD 0 |
1218 | .PD 0 |
1073 | .IP "ev_io_set (ev_io *, int fd, int events)" 4 |
1219 | .IP "ev_io_set (ev_io *, int fd, int events)" 4 |
1074 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
1220 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
… | |
… | |
1127 | .Ve |
1273 | .Ve |
1128 | .PP |
1274 | .PP |
1129 | The callback is guarenteed to be invoked only when its timeout has passed, |
1275 | The callback is guarenteed to be invoked only when its timeout has passed, |
1130 | but if multiple timers become ready during the same loop iteration then |
1276 | but if multiple timers become ready during the same loop iteration then |
1131 | order of execution is undefined. |
1277 | order of execution is undefined. |
|
|
1278 | .PP |
|
|
1279 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1280 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1132 | .IP "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" 4 |
1281 | .IP "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" 4 |
1133 | .IX Item "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" |
1282 | .IX Item "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" |
1134 | .PD 0 |
1283 | .PD 0 |
1135 | .IP "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)" 4 |
1284 | .IP "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)" 4 |
1136 | .IX Item "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)" |
1285 | .IX Item "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)" |
… | |
… | |
1247 | rules. |
1396 | rules. |
1248 | .PP |
1397 | .PP |
1249 | As with timers, the callback is guarenteed to be invoked only when the |
1398 | As with timers, the callback is guarenteed to be invoked only when the |
1250 | time (\f(CW\*(C`at\*(C'\fR) has been passed, but if multiple periodic timers become ready |
1399 | time (\f(CW\*(C`at\*(C'\fR) has been passed, but if multiple periodic timers become ready |
1251 | during the same loop iteration then order of execution is undefined. |
1400 | during the same loop iteration then order of execution is undefined. |
|
|
1401 | .PP |
|
|
1402 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1403 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1252 | .IP "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" 4 |
1404 | .IP "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" 4 |
1253 | .IX Item "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" |
1405 | .IX Item "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" |
1254 | .PD 0 |
1406 | .PD 0 |
1255 | .IP "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" 4 |
1407 | .IP "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" 4 |
1256 | .IX Item "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" |
1408 | .IX Item "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" |
… | |
… | |
1348 | .IP "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read\-write]" 4 |
1500 | .IP "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read\-write]" 4 |
1349 | .IX Item "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write]" |
1501 | .IX Item "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write]" |
1350 | The current reschedule callback, or \f(CW0\fR, if this functionality is |
1502 | The current reschedule callback, or \f(CW0\fR, if this functionality is |
1351 | switched off. Can be changed any time, but changes only take effect when |
1503 | switched off. Can be changed any time, but changes only take effect when |
1352 | the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called. |
1504 | the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called. |
|
|
1505 | .IP "ev_tstamp at [read\-only]" 4 |
|
|
1506 | .IX Item "ev_tstamp at [read-only]" |
|
|
1507 | When active, contains the absolute time that the watcher is supposed to |
|
|
1508 | trigger next. |
1353 | .PP |
1509 | .PP |
1354 | Example: Call a callback every hour, or, more precisely, whenever the |
1510 | Example: Call a callback every hour, or, more precisely, whenever the |
1355 | system clock is divisible by 3600. The callback invocation times have |
1511 | system clock is divisible by 3600. The callback invocation times have |
1356 | potentially a lot of jittering, but good long-term stability. |
1512 | potentially a lot of jittering, but good long-term stability. |
1357 | .PP |
1513 | .PP |
… | |
… | |
1407 | first watcher gets started will libev actually register a signal watcher |
1563 | first watcher gets started will libev actually register a signal watcher |
1408 | with the kernel (thus it coexists with your own signal handlers as long |
1564 | with the kernel (thus it coexists with your own signal handlers as long |
1409 | as you don't register any with libev). Similarly, when the last signal |
1565 | as you don't register any with libev). Similarly, when the last signal |
1410 | watcher for a signal is stopped libev will reset the signal handler to |
1566 | watcher for a signal is stopped libev will reset the signal handler to |
1411 | \&\s-1SIG_DFL\s0 (regardless of what it was set to before). |
1567 | \&\s-1SIG_DFL\s0 (regardless of what it was set to before). |
|
|
1568 | .PP |
|
|
1569 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1570 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1412 | .IP "ev_signal_init (ev_signal *, callback, int signum)" 4 |
1571 | .IP "ev_signal_init (ev_signal *, callback, int signum)" 4 |
1413 | .IX Item "ev_signal_init (ev_signal *, callback, int signum)" |
1572 | .IX Item "ev_signal_init (ev_signal *, callback, int signum)" |
1414 | .PD 0 |
1573 | .PD 0 |
1415 | .IP "ev_signal_set (ev_signal *, int signum)" 4 |
1574 | .IP "ev_signal_set (ev_signal *, int signum)" 4 |
1416 | .IX Item "ev_signal_set (ev_signal *, int signum)" |
1575 | .IX Item "ev_signal_set (ev_signal *, int signum)" |
… | |
… | |
1423 | .ie n .Sh """ev_child"" \- watch out for process status changes" |
1582 | .ie n .Sh """ev_child"" \- watch out for process status changes" |
1424 | .el .Sh "\f(CWev_child\fP \- watch out for process status changes" |
1583 | .el .Sh "\f(CWev_child\fP \- watch out for process status changes" |
1425 | .IX Subsection "ev_child - watch out for process status changes" |
1584 | .IX Subsection "ev_child - watch out for process status changes" |
1426 | Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to |
1585 | Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to |
1427 | some child status changes (most typically when a child of yours dies). |
1586 | some child status changes (most typically when a child of yours dies). |
|
|
1587 | .PP |
|
|
1588 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1589 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1428 | .IP "ev_child_init (ev_child *, callback, int pid)" 4 |
1590 | .IP "ev_child_init (ev_child *, callback, int pid)" 4 |
1429 | .IX Item "ev_child_init (ev_child *, callback, int pid)" |
1591 | .IX Item "ev_child_init (ev_child *, callback, int pid)" |
1430 | .PD 0 |
1592 | .PD 0 |
1431 | .IP "ev_child_set (ev_child *, int pid)" 4 |
1593 | .IP "ev_child_set (ev_child *, int pid)" 4 |
1432 | .IX Item "ev_child_set (ev_child *, int pid)" |
1594 | .IX Item "ev_child_set (ev_child *, int pid)" |
… | |
… | |
1497 | reader). Inotify will be used to give hints only and should not change the |
1659 | reader). Inotify will be used to give hints only and should not change the |
1498 | semantics of \f(CW\*(C`ev_stat\*(C'\fR watchers, which means that libev sometimes needs |
1660 | semantics of \f(CW\*(C`ev_stat\*(C'\fR watchers, which means that libev sometimes needs |
1499 | to fall back to regular polling again even with inotify, but changes are |
1661 | to fall back to regular polling again even with inotify, but changes are |
1500 | usually detected immediately, and if the file exists there will be no |
1662 | usually detected immediately, and if the file exists there will be no |
1501 | polling. |
1663 | polling. |
|
|
1664 | .PP |
|
|
1665 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1666 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1502 | .IP "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" 4 |
1667 | .IP "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" 4 |
1503 | .IX Item "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" |
1668 | .IX Item "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" |
1504 | .PD 0 |
1669 | .PD 0 |
1505 | .IP "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" 4 |
1670 | .IP "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" 4 |
1506 | .IX Item "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" |
1671 | .IX Item "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" |
… | |
… | |
1585 | .PP |
1750 | .PP |
1586 | Apart from keeping your process non-blocking (which is a useful |
1751 | Apart from keeping your process non-blocking (which is a useful |
1587 | effect on its own sometimes), idle watchers are a good place to do |
1752 | effect on its own sometimes), idle watchers are a good place to do |
1588 | \&\*(L"pseudo\-background processing\*(R", or delay processing stuff to after the |
1753 | \&\*(L"pseudo\-background processing\*(R", or delay processing stuff to after the |
1589 | event loop has handled all outstanding events. |
1754 | event loop has handled all outstanding events. |
|
|
1755 | .PP |
|
|
1756 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1757 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1590 | .IP "ev_idle_init (ev_signal *, callback)" 4 |
1758 | .IP "ev_idle_init (ev_signal *, callback)" 4 |
1591 | .IX Item "ev_idle_init (ev_signal *, callback)" |
1759 | .IX Item "ev_idle_init (ev_signal *, callback)" |
1592 | Initialises and configures the idle watcher \- it has no parameters of any |
1760 | Initialises and configures the idle watcher \- it has no parameters of any |
1593 | kind. There is a \f(CW\*(C`ev_idle_set\*(C'\fR macro, but using it is utterly pointless, |
1761 | kind. There is a \f(CW\*(C`ev_idle_set\*(C'\fR macro, but using it is utterly pointless, |
1594 | believe me. |
1762 | believe me. |
… | |
… | |
1654 | .PP |
1822 | .PP |
1655 | It is recommended to give \f(CW\*(C`ev_check\*(C'\fR watchers highest (\f(CW\*(C`EV_MAXPRI\*(C'\fR) |
1823 | It is recommended to give \f(CW\*(C`ev_check\*(C'\fR watchers highest (\f(CW\*(C`EV_MAXPRI\*(C'\fR) |
1656 | priority, to ensure that they are being run before any other watchers |
1824 | priority, to ensure that they are being run before any other watchers |
1657 | after the poll. Also, \f(CW\*(C`ev_check\*(C'\fR watchers (and \f(CW\*(C`ev_prepare\*(C'\fR watchers, |
1825 | after the poll. Also, \f(CW\*(C`ev_check\*(C'\fR watchers (and \f(CW\*(C`ev_prepare\*(C'\fR watchers, |
1658 | too) should not activate (\*(L"feed\*(R") events into libev. While libev fully |
1826 | too) should not activate (\*(L"feed\*(R") events into libev. While libev fully |
1659 | supports this, they will be called before other \f(CW\*(C`ev_check\*(C'\fR watchers did |
1827 | supports this, they will be called before other \f(CW\*(C`ev_check\*(C'\fR watchers |
1660 | their job. As \f(CW\*(C`ev_check\*(C'\fR watchers are often used to embed other event |
1828 | did their job. As \f(CW\*(C`ev_check\*(C'\fR watchers are often used to embed other |
1661 | loops those other event loops might be in an unusable state until their |
1829 | (non\-libev) event loops those other event loops might be in an unusable |
1662 | \&\f(CW\*(C`ev_check\*(C'\fR watcher ran (always remind yourself to coexist peacefully with |
1830 | state until their \f(CW\*(C`ev_check\*(C'\fR watcher ran (always remind yourself to |
1663 | others). |
1831 | coexist peacefully with others). |
|
|
1832 | .PP |
|
|
1833 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
1834 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1664 | .IP "ev_prepare_init (ev_prepare *, callback)" 4 |
1835 | .IP "ev_prepare_init (ev_prepare *, callback)" 4 |
1665 | .IX Item "ev_prepare_init (ev_prepare *, callback)" |
1836 | .IX Item "ev_prepare_init (ev_prepare *, callback)" |
1666 | .PD 0 |
1837 | .PD 0 |
1667 | .IP "ev_check_init (ev_check *, callback)" 4 |
1838 | .IP "ev_check_init (ev_check *, callback)" 4 |
1668 | .IX Item "ev_check_init (ev_check *, callback)" |
1839 | .IX Item "ev_check_init (ev_check *, callback)" |
… | |
… | |
1915 | \& ev_embed_start (loop_hi, &embed); |
2086 | \& ev_embed_start (loop_hi, &embed); |
1916 | \& } |
2087 | \& } |
1917 | \& else |
2088 | \& else |
1918 | \& loop_lo = loop_hi; |
2089 | \& loop_lo = loop_hi; |
1919 | .Ve |
2090 | .Ve |
|
|
2091 | .PP |
|
|
2092 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
2093 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1920 | .IP "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
2094 | .IP "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
1921 | .IX Item "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" |
2095 | .IX Item "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" |
1922 | .PD 0 |
2096 | .PD 0 |
1923 | .IP "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
2097 | .IP "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
1924 | .IX Item "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" |
2098 | .IX Item "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" |
… | |
… | |
1931 | .IP "ev_embed_sweep (loop, ev_embed *)" 4 |
2105 | .IP "ev_embed_sweep (loop, ev_embed *)" 4 |
1932 | .IX Item "ev_embed_sweep (loop, ev_embed *)" |
2106 | .IX Item "ev_embed_sweep (loop, ev_embed *)" |
1933 | Make a single, non-blocking sweep over the embedded loop. This works |
2107 | Make a single, non-blocking sweep over the embedded loop. This works |
1934 | similarly to \f(CW\*(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\*(C'\fR, but in the most |
2108 | similarly to \f(CW\*(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\*(C'\fR, but in the most |
1935 | apropriate way for embedded loops. |
2109 | apropriate way for embedded loops. |
1936 | .IP "struct ev_loop *loop [read\-only]" 4 |
2110 | .IP "struct ev_loop *other [read\-only]" 4 |
1937 | .IX Item "struct ev_loop *loop [read-only]" |
2111 | .IX Item "struct ev_loop *other [read-only]" |
1938 | The embedded event loop. |
2112 | The embedded event loop. |
1939 | .ie n .Sh """ev_fork"" \- the audacity to resume the event loop after a fork" |
2113 | .ie n .Sh """ev_fork"" \- the audacity to resume the event loop after a fork" |
1940 | .el .Sh "\f(CWev_fork\fP \- the audacity to resume the event loop after a fork" |
2114 | .el .Sh "\f(CWev_fork\fP \- the audacity to resume the event loop after a fork" |
1941 | .IX Subsection "ev_fork - the audacity to resume the event loop after a fork" |
2115 | .IX Subsection "ev_fork - the audacity to resume the event loop after a fork" |
1942 | Fork watchers are called when a \f(CW\*(C`fork ()\*(C'\fR was detected (usually because |
2116 | Fork watchers are called when a \f(CW\*(C`fork ()\*(C'\fR was detected (usually because |
… | |
… | |
1944 | \&\f(CW\*(C`ev_default_fork\*(C'\fR or \f(CW\*(C`ev_loop_fork\*(C'\fR). The invocation is done before the |
2118 | \&\f(CW\*(C`ev_default_fork\*(C'\fR or \f(CW\*(C`ev_loop_fork\*(C'\fR). The invocation is done before the |
1945 | event loop blocks next and before \f(CW\*(C`ev_check\*(C'\fR watchers are being called, |
2119 | event loop blocks next and before \f(CW\*(C`ev_check\*(C'\fR watchers are being called, |
1946 | and only in the child after the fork. If whoever good citizen calling |
2120 | and only in the child after the fork. If whoever good citizen calling |
1947 | \&\f(CW\*(C`ev_default_fork\*(C'\fR cheats and calls it in the wrong process, the fork |
2121 | \&\f(CW\*(C`ev_default_fork\*(C'\fR cheats and calls it in the wrong process, the fork |
1948 | handlers will be invoked, too, of course. |
2122 | handlers will be invoked, too, of course. |
|
|
2123 | .PP |
|
|
2124 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
2125 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1949 | .IP "ev_fork_init (ev_signal *, callback)" 4 |
2126 | .IP "ev_fork_init (ev_signal *, callback)" 4 |
1950 | .IX Item "ev_fork_init (ev_signal *, callback)" |
2127 | .IX Item "ev_fork_init (ev_signal *, callback)" |
1951 | Initialises and configures the fork watcher \- it has no parameters of any |
2128 | Initialises and configures the fork watcher \- it has no parameters of any |
1952 | kind. There is a \f(CW\*(C`ev_fork_set\*(C'\fR macro, but using it is utterly pointless, |
2129 | kind. There is a \f(CW\*(C`ev_fork_set\*(C'\fR macro, but using it is utterly pointless, |
1953 | believe me. |
2130 | believe me. |
… | |
… | |
2147 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument, as the |
2324 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument, as the |
2148 | constructor already stores the event loop. |
2325 | constructor already stores the event loop. |
2149 | .IP "w\->stop ()" 4 |
2326 | .IP "w\->stop ()" 4 |
2150 | .IX Item "w->stop ()" |
2327 | .IX Item "w->stop ()" |
2151 | Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument. |
2328 | Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument. |
2152 | .ie n .IP "w\->again () ""ev::timer""\fR, \f(CW""ev::periodic"" only" 4 |
2329 | .ie n .IP "w\->again () (""ev::timer""\fR, \f(CW""ev::periodic"" only)" 4 |
2153 | .el .IP "w\->again () \f(CWev::timer\fR, \f(CWev::periodic\fR only" 4 |
2330 | .el .IP "w\->again () (\f(CWev::timer\fR, \f(CWev::periodic\fR only)" 4 |
2154 | .IX Item "w->again () ev::timer, ev::periodic only" |
2331 | .IX Item "w->again () (ev::timer, ev::periodic only)" |
2155 | For \f(CW\*(C`ev::timer\*(C'\fR and \f(CW\*(C`ev::periodic\*(C'\fR, this invokes the corresponding |
2332 | For \f(CW\*(C`ev::timer\*(C'\fR and \f(CW\*(C`ev::periodic\*(C'\fR, this invokes the corresponding |
2156 | \&\f(CW\*(C`ev_TYPE_again\*(C'\fR function. |
2333 | \&\f(CW\*(C`ev_TYPE_again\*(C'\fR function. |
2157 | .ie n .IP "w\->sweep () ""ev::embed"" only" 4 |
2334 | .ie n .IP "w\->sweep () (""ev::embed"" only)" 4 |
2158 | .el .IP "w\->sweep () \f(CWev::embed\fR only" 4 |
2335 | .el .IP "w\->sweep () (\f(CWev::embed\fR only)" 4 |
2159 | .IX Item "w->sweep () ev::embed only" |
2336 | .IX Item "w->sweep () (ev::embed only)" |
2160 | Invokes \f(CW\*(C`ev_embed_sweep\*(C'\fR. |
2337 | Invokes \f(CW\*(C`ev_embed_sweep\*(C'\fR. |
2161 | .ie n .IP "w\->update () ""ev::stat"" only" 4 |
2338 | .ie n .IP "w\->update () (""ev::stat"" only)" 4 |
2162 | .el .IP "w\->update () \f(CWev::stat\fR only" 4 |
2339 | .el .IP "w\->update () (\f(CWev::stat\fR only)" 4 |
2163 | .IX Item "w->update () ev::stat only" |
2340 | .IX Item "w->update () (ev::stat only)" |
2164 | Invokes \f(CW\*(C`ev_stat_stat\*(C'\fR. |
2341 | Invokes \f(CW\*(C`ev_stat_stat\*(C'\fR. |
2165 | .RE |
2342 | .RE |
2166 | .RS 4 |
2343 | .RS 4 |
2167 | .RE |
2344 | .RE |
2168 | .PP |
2345 | .PP |
… | |
… | |
2192 | \& io.start (fd, ev::READ); |
2369 | \& io.start (fd, ev::READ); |
2193 | \& } |
2370 | \& } |
2194 | .Ve |
2371 | .Ve |
2195 | .SH "MACRO MAGIC" |
2372 | .SH "MACRO MAGIC" |
2196 | .IX Header "MACRO MAGIC" |
2373 | .IX Header "MACRO MAGIC" |
2197 | Libev can be compiled with a variety of options, the most fundemantal is |
2374 | Libev can be compiled with a variety of options, the most fundamantal |
2198 | \&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines whether (most) functions and |
2375 | of which is \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines whether (most) |
2199 | callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument. |
2376 | functions and callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument. |
2200 | .PP |
2377 | .PP |
2201 | To make it easier to write programs that cope with either variant, the |
2378 | To make it easier to write programs that cope with either variant, the |
2202 | following macros are defined: |
2379 | following macros are defined: |
2203 | .ie n .IP """EV_A""\fR, \f(CW""EV_A_""" 4 |
2380 | .ie n .IP """EV_A""\fR, \f(CW""EV_A_""" 4 |
2204 | .el .IP "\f(CWEV_A\fR, \f(CWEV_A_\fR" 4 |
2381 | .el .IP "\f(CWEV_A\fR, \f(CWEV_A_\fR" 4 |
… | |
… | |
2263 | Libev can (and often is) directly embedded into host |
2440 | Libev can (and often is) directly embedded into host |
2264 | applications. Examples of applications that embed it include the Deliantra |
2441 | applications. Examples of applications that embed it include the Deliantra |
2265 | Game Server, the \s-1EV\s0 perl module, the \s-1GNU\s0 Virtual Private Ethernet (gvpe) |
2442 | Game Server, the \s-1EV\s0 perl module, the \s-1GNU\s0 Virtual Private Ethernet (gvpe) |
2266 | and rxvt\-unicode. |
2443 | and rxvt\-unicode. |
2267 | .PP |
2444 | .PP |
2268 | The goal is to enable you to just copy the neecssary files into your |
2445 | The goal is to enable you to just copy the necessary files into your |
2269 | source directory without having to change even a single line in them, so |
2446 | source directory without having to change even a single line in them, so |
2270 | you can easily upgrade by simply copying (or having a checked-out copy of |
2447 | you can easily upgrade by simply copying (or having a checked-out copy of |
2271 | libev somewhere in your source tree). |
2448 | libev somewhere in your source tree). |
2272 | .Sh "\s-1FILESETS\s0" |
2449 | .Sh "\s-1FILESETS\s0" |
2273 | .IX Subsection "FILESETS" |
2450 | .IX Subsection "FILESETS" |
… | |
… | |
2378 | .IX Item "EV_USE_MONOTONIC" |
2555 | .IX Item "EV_USE_MONOTONIC" |
2379 | If defined to be \f(CW1\fR, libev will try to detect the availability of the |
2556 | If defined to be \f(CW1\fR, libev will try to detect the availability of the |
2380 | monotonic clock option at both compiletime and runtime. Otherwise no use |
2557 | monotonic clock option at both compiletime and runtime. Otherwise no use |
2381 | of the monotonic clock option will be attempted. If you enable this, you |
2558 | of the monotonic clock option will be attempted. If you enable this, you |
2382 | usually have to link against librt or something similar. Enabling it when |
2559 | usually have to link against librt or something similar. Enabling it when |
2383 | the functionality isn't available is safe, though, althoguh you have |
2560 | the functionality isn't available is safe, though, although you have |
2384 | to make sure you link against any libraries where the \f(CW\*(C`clock_gettime\*(C'\fR |
2561 | to make sure you link against any libraries where the \f(CW\*(C`clock_gettime\*(C'\fR |
2385 | function is hiding in (often \fI\-lrt\fR). |
2562 | function is hiding in (often \fI\-lrt\fR). |
2386 | .IP "\s-1EV_USE_REALTIME\s0" 4 |
2563 | .IP "\s-1EV_USE_REALTIME\s0" 4 |
2387 | .IX Item "EV_USE_REALTIME" |
2564 | .IX Item "EV_USE_REALTIME" |
2388 | If defined to be \f(CW1\fR, libev will try to detect the availability of the |
2565 | If defined to be \f(CW1\fR, libev will try to detect the availability of the |
2389 | realtime clock option at compiletime (and assume its availability at |
2566 | realtime clock option at compiletime (and assume its availability at |
2390 | runtime if successful). Otherwise no use of the realtime clock option will |
2567 | runtime if successful). Otherwise no use of the realtime clock option will |
2391 | be attempted. This effectively replaces \f(CW\*(C`gettimeofday\*(C'\fR by \f(CW\*(C`clock_get |
2568 | be attempted. This effectively replaces \f(CW\*(C`gettimeofday\*(C'\fR by \f(CW\*(C`clock_get |
2392 | (CLOCK_REALTIME, ...)\*(C'\fR and will not normally affect correctness. See tzhe note about libraries |
2569 | (CLOCK_REALTIME, ...)\*(C'\fR and will not normally affect correctness. See the |
2393 | in the description of \f(CW\*(C`EV_USE_MONOTONIC\*(C'\fR, though. |
2570 | note about libraries in the description of \f(CW\*(C`EV_USE_MONOTONIC\*(C'\fR, though. |
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|
2571 | .IP "\s-1EV_USE_NANOSLEEP\s0" 4 |
|
|
2572 | .IX Item "EV_USE_NANOSLEEP" |
|
|
2573 | If defined to be \f(CW1\fR, libev will assume that \f(CW\*(C`nanosleep ()\*(C'\fR is available |
|
|
2574 | and will use it for delays. Otherwise it will use \f(CW\*(C`select ()\*(C'\fR. |
2394 | .IP "\s-1EV_USE_SELECT\s0" 4 |
2575 | .IP "\s-1EV_USE_SELECT\s0" 4 |
2395 | .IX Item "EV_USE_SELECT" |
2576 | .IX Item "EV_USE_SELECT" |
2396 | If undefined or defined to be \f(CW1\fR, libev will compile in support for the |
2577 | If undefined or defined to be \f(CW1\fR, libev will compile in support for the |
2397 | \&\f(CW\*(C`select\*(C'\fR(2) backend. No attempt at autodetection will be done: if no |
2578 | \&\f(CW\*(C`select\*(C'\fR(2) backend. No attempt at autodetection will be done: if no |
2398 | other method takes over, select will be it. Otherwise the select backend |
2579 | other method takes over, select will be it. Otherwise the select backend |
… | |
… | |
2558 | .IP "ev_set_cb (ev, cb)" 4 |
2739 | .IP "ev_set_cb (ev, cb)" 4 |
2559 | .IX Item "ev_set_cb (ev, cb)" |
2740 | .IX Item "ev_set_cb (ev, cb)" |
2560 | .PD |
2741 | .PD |
2561 | Can be used to change the callback member declaration in each watcher, |
2742 | Can be used to change the callback member declaration in each watcher, |
2562 | and the way callbacks are invoked and set. Must expand to a struct member |
2743 | and the way callbacks are invoked and set. Must expand to a struct member |
2563 | definition and a statement, respectively. See the \fIev.v\fR header file for |
2744 | definition and a statement, respectively. See the \fIev.h\fR header file for |
2564 | their default definitions. One possible use for overriding these is to |
2745 | their default definitions. One possible use for overriding these is to |
2565 | avoid the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument in all cases, or to use |
2746 | avoid the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument in all cases, or to use |
2566 | method calls instead of plain function calls in \*(C+. |
2747 | method calls instead of plain function calls in \*(C+. |
|
|
2748 | .Sh "\s-1EXPORTED\s0 \s-1API\s0 \s-1SYMBOLS\s0" |
|
|
2749 | .IX Subsection "EXPORTED API SYMBOLS" |
|
|
2750 | If you need to re-export the \s-1API\s0 (e.g. via a dll) and you need a list of |
|
|
2751 | exported symbols, you can use the provided \fISymbol.*\fR files which list |
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|
2752 | all public symbols, one per line: |
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|
2753 | .Sp |
|
|
2754 | .Vb 2 |
|
|
2755 | \& Symbols.ev for libev proper |
|
|
2756 | \& Symbols.event for the libevent emulation |
|
|
2757 | .Ve |
|
|
2758 | .Sp |
|
|
2759 | This can also be used to rename all public symbols to avoid clashes with |
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|
2760 | multiple versions of libev linked together (which is obviously bad in |
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|
2761 | itself, but sometimes it is inconvinient to avoid this). |
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|
2762 | .Sp |
|
|
2763 | A sed command like this will create wrapper \f(CW\*(C`#define\*(C'\fR's that you need to |
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|
2764 | include before including \fIev.h\fR: |
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|
2765 | .Sp |
|
|
2766 | .Vb 1 |
|
|
2767 | \& <Symbols.ev sed -e "s/.*/#define & myprefix_&/" >wrap.h |
|
|
2768 | .Ve |
|
|
2769 | .Sp |
|
|
2770 | This would create a file \fIwrap.h\fR which essentially looks like this: |
|
|
2771 | .Sp |
|
|
2772 | .Vb 4 |
|
|
2773 | \& #define ev_backend myprefix_ev_backend |
|
|
2774 | \& #define ev_check_start myprefix_ev_check_start |
|
|
2775 | \& #define ev_check_stop myprefix_ev_check_stop |
|
|
2776 | \& ... |
|
|
2777 | .Ve |
2567 | .Sh "\s-1EXAMPLES\s0" |
2778 | .Sh "\s-1EXAMPLES\s0" |
2568 | .IX Subsection "EXAMPLES" |
2779 | .IX Subsection "EXAMPLES" |
2569 | For a real-world example of a program the includes libev |
2780 | For a real-world example of a program the includes libev |
2570 | verbatim, you can have a look at the \s-1EV\s0 perl module |
2781 | verbatim, you can have a look at the \s-1EV\s0 perl module |
2571 | (<http://software.schmorp.de/pkg/EV.html>). It has the libev files in |
2782 | (<http://software.schmorp.de/pkg/EV.html>). It has the libev files in |