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126 | .IX Title "LIBEV 3" |
135 | .IX Title "LIBEV 3" |
127 | .TH LIBEV 3 "2012-04-19" "libev-4.11" "libev - high performance full featured event loop" |
136 | .TH LIBEV 3 "2019-06-22" "libev-4.25" "libev - high performance full featured event loop" |
128 | .\" For nroff, turn off justification. Always turn off hyphenation; it makes |
137 | .\" For nroff, turn off justification. Always turn off hyphenation; it makes |
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130 | .if n .ad l |
139 | .if n .ad l |
131 | .nh |
140 | .nh |
132 | .SH "NAME" |
141 | .SH "NAME" |
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134 | .SH "SYNOPSIS" |
143 | .SH "SYNOPSIS" |
135 | .IX Header "SYNOPSIS" |
144 | .IX Header "SYNOPSIS" |
136 | .Vb 1 |
145 | .Vb 1 |
137 | \& #include <ev.h> |
146 | \& #include <ev.h> |
138 | .Ve |
147 | .Ve |
139 | .SS "\s-1EXAMPLE\s0 \s-1PROGRAM\s0" |
148 | .SS "\s-1EXAMPLE PROGRAM\s0" |
140 | .IX Subsection "EXAMPLE PROGRAM" |
149 | .IX Subsection "EXAMPLE PROGRAM" |
141 | .Vb 2 |
150 | .Vb 2 |
142 | \& // a single header file is required |
151 | \& // a single header file is required |
143 | \& #include <ev.h> |
152 | \& #include <ev.h> |
144 | \& |
153 | \& |
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212 | throughout this document. |
221 | throughout this document. |
213 | .SH "WHAT TO READ WHEN IN A HURRY" |
222 | .SH "WHAT TO READ WHEN IN A HURRY" |
214 | .IX Header "WHAT TO READ WHEN IN A HURRY" |
223 | .IX Header "WHAT TO READ WHEN IN A HURRY" |
215 | This manual tries to be very detailed, but unfortunately, this also makes |
224 | This manual tries to be very detailed, but unfortunately, this also makes |
216 | it very long. If you just want to know the basics of libev, I suggest |
225 | it very long. If you just want to know the basics of libev, I suggest |
217 | reading \*(L"\s-1ANATOMY\s0 \s-1OF\s0 A \s-1WATCHER\s0\*(R", then the \*(L"\s-1EXAMPLE\s0 \s-1PROGRAM\s0\*(R" above and |
226 | reading \*(L"\s-1ANATOMY OF A WATCHER\*(R"\s0, then the \*(L"\s-1EXAMPLE PROGRAM\*(R"\s0 above and |
218 | look up the missing functions in \*(L"\s-1GLOBAL\s0 \s-1FUNCTIONS\s0\*(R" and the \f(CW\*(C`ev_io\*(C'\fR and |
227 | look up the missing functions in \*(L"\s-1GLOBAL FUNCTIONS\*(R"\s0 and the \f(CW\*(C`ev_io\*(C'\fR and |
219 | \&\f(CW\*(C`ev_timer\*(C'\fR sections in \*(L"\s-1WATCHER\s0 \s-1TYPES\s0\*(R". |
228 | \&\f(CW\*(C`ev_timer\*(C'\fR sections in \*(L"\s-1WATCHER TYPES\*(R"\s0. |
220 | .SH "ABOUT LIBEV" |
229 | .SH "ABOUT LIBEV" |
221 | .IX Header "ABOUT LIBEV" |
230 | .IX Header "ABOUT LIBEV" |
222 | Libev is an event loop: you register interest in certain events (such as a |
231 | Libev is an event loop: you register interest in certain events (such as a |
223 | file descriptor being readable or a timeout occurring), and it will manage |
232 | file descriptor being readable or a timeout occurring), and it will manage |
224 | these event sources and provide your program with events. |
233 | these event sources and provide your program with events. |
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231 | watchers\fR, which are relatively small C structures you initialise with the |
240 | watchers\fR, which are relatively small C structures you initialise with the |
232 | details of the event, and then hand it over to libev by \fIstarting\fR the |
241 | details of the event, and then hand it over to libev by \fIstarting\fR the |
233 | watcher. |
242 | watcher. |
234 | .SS "\s-1FEATURES\s0" |
243 | .SS "\s-1FEATURES\s0" |
235 | .IX Subsection "FEATURES" |
244 | .IX Subsection "FEATURES" |
236 | Libev supports \f(CW\*(C`select\*(C'\fR, \f(CW\*(C`poll\*(C'\fR, the Linux-specific \f(CW\*(C`epoll\*(C'\fR, the |
245 | Libev supports \f(CW\*(C`select\*(C'\fR, \f(CW\*(C`poll\*(C'\fR, the Linux-specific aio and \f(CW\*(C`epoll\*(C'\fR |
237 | BSD-specific \f(CW\*(C`kqueue\*(C'\fR and the Solaris-specific event port mechanisms |
246 | interfaces, the BSD-specific \f(CW\*(C`kqueue\*(C'\fR and the Solaris-specific event port |
238 | for file descriptor events (\f(CW\*(C`ev_io\*(C'\fR), the Linux \f(CW\*(C`inotify\*(C'\fR interface |
247 | mechanisms for file descriptor events (\f(CW\*(C`ev_io\*(C'\fR), the Linux \f(CW\*(C`inotify\*(C'\fR |
239 | (for \f(CW\*(C`ev_stat\*(C'\fR), Linux eventfd/signalfd (for faster and cleaner |
248 | interface (for \f(CW\*(C`ev_stat\*(C'\fR), Linux eventfd/signalfd (for faster and cleaner |
240 | inter-thread wakeup (\f(CW\*(C`ev_async\*(C'\fR)/signal handling (\f(CW\*(C`ev_signal\*(C'\fR)) relative |
249 | inter-thread wakeup (\f(CW\*(C`ev_async\*(C'\fR)/signal handling (\f(CW\*(C`ev_signal\*(C'\fR)) relative |
241 | timers (\f(CW\*(C`ev_timer\*(C'\fR), absolute timers with customised rescheduling |
250 | timers (\f(CW\*(C`ev_timer\*(C'\fR), absolute timers with customised rescheduling |
242 | (\f(CW\*(C`ev_periodic\*(C'\fR), synchronous signals (\f(CW\*(C`ev_signal\*(C'\fR), process status |
251 | (\f(CW\*(C`ev_periodic\*(C'\fR), synchronous signals (\f(CW\*(C`ev_signal\*(C'\fR), process status |
243 | change events (\f(CW\*(C`ev_child\*(C'\fR), and event watchers dealing with the event |
252 | change events (\f(CW\*(C`ev_child\*(C'\fR), and event watchers dealing with the event |
244 | loop mechanism itself (\f(CW\*(C`ev_idle\*(C'\fR, \f(CW\*(C`ev_embed\*(C'\fR, \f(CW\*(C`ev_prepare\*(C'\fR and |
253 | loop mechanism itself (\f(CW\*(C`ev_idle\*(C'\fR, \f(CW\*(C`ev_embed\*(C'\fR, \f(CW\*(C`ev_prepare\*(C'\fR and |
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255 | more info about various configuration options please have a look at |
264 | more info about various configuration options please have a look at |
256 | \&\fB\s-1EMBED\s0\fR section in this manual. If libev was configured without support |
265 | \&\fB\s-1EMBED\s0\fR section in this manual. If libev was configured without support |
257 | for multiple event loops, then all functions taking an initial argument of |
266 | for multiple event loops, then all functions taking an initial argument of |
258 | name \f(CW\*(C`loop\*(C'\fR (which is always of type \f(CW\*(C`struct ev_loop *\*(C'\fR) will not have |
267 | name \f(CW\*(C`loop\*(C'\fR (which is always of type \f(CW\*(C`struct ev_loop *\*(C'\fR) will not have |
259 | this argument. |
268 | this argument. |
260 | .SS "\s-1TIME\s0 \s-1REPRESENTATION\s0" |
269 | .SS "\s-1TIME REPRESENTATION\s0" |
261 | .IX Subsection "TIME REPRESENTATION" |
270 | .IX Subsection "TIME REPRESENTATION" |
262 | Libev represents time as a single floating point number, representing |
271 | Libev represents time as a single floating point number, representing |
263 | the (fractional) number of seconds since the (\s-1POSIX\s0) epoch (in practice |
272 | the (fractional) number of seconds since the (\s-1POSIX\s0) epoch (in practice |
264 | somewhere near the beginning of 1970, details are complicated, don't |
273 | somewhere near the beginning of 1970, details are complicated, don't |
265 | ask). This type is called \f(CW\*(C`ev_tstamp\*(C'\fR, which is what you should use |
274 | ask). This type is called \f(CW\*(C`ev_tstamp\*(C'\fR, which is what you should use |
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383 | .Sp |
392 | .Sp |
384 | You could override this function in high-availability programs to, say, |
393 | You could override this function in high-availability programs to, say, |
385 | free some memory if it cannot allocate memory, to use a special allocator, |
394 | free some memory if it cannot allocate memory, to use a special allocator, |
386 | or even to sleep a while and retry until some memory is available. |
395 | or even to sleep a while and retry until some memory is available. |
387 | .Sp |
396 | .Sp |
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397 | Example: The following is the \f(CW\*(C`realloc\*(C'\fR function that libev itself uses |
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398 | which should work with \f(CW\*(C`realloc\*(C'\fR and \f(CW\*(C`free\*(C'\fR functions of all kinds and |
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399 | is probably a good basis for your own implementation. |
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400 | .Sp |
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401 | .Vb 5 |
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402 | \& static void * |
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403 | \& ev_realloc_emul (void *ptr, long size) EV_NOEXCEPT |
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404 | \& { |
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405 | \& if (size) |
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406 | \& return realloc (ptr, size); |
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407 | \& |
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408 | \& free (ptr); |
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409 | \& return 0; |
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410 | \& } |
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411 | .Ve |
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412 | .Sp |
388 | Example: Replace the libev allocator with one that waits a bit and then |
413 | Example: Replace the libev allocator with one that waits a bit and then |
389 | retries (example requires a standards-compliant \f(CW\*(C`realloc\*(C'\fR). |
414 | retries. |
390 | .Sp |
415 | .Sp |
391 | .Vb 6 |
416 | .Vb 8 |
392 | \& static void * |
417 | \& static void * |
393 | \& persistent_realloc (void *ptr, size_t size) |
418 | \& persistent_realloc (void *ptr, size_t size) |
394 | \& { |
419 | \& { |
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420 | \& if (!size) |
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421 | \& { |
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422 | \& free (ptr); |
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423 | \& return 0; |
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424 | \& } |
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425 | \& |
395 | \& for (;;) |
426 | \& for (;;) |
396 | \& { |
427 | \& { |
397 | \& void *newptr = realloc (ptr, size); |
428 | \& void *newptr = realloc (ptr, size); |
398 | \& |
429 | \& |
399 | \& if (newptr) |
430 | \& if (newptr) |
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514 | .IX Item "EVFLAG_NOENV" |
545 | .IX Item "EVFLAG_NOENV" |
515 | If this flag bit is or'ed into the flag value (or the program runs setuid |
546 | If this flag bit is or'ed into the flag value (or the program runs setuid |
516 | or setgid) then libev will \fInot\fR look at the environment variable |
547 | or setgid) then libev will \fInot\fR look at the environment variable |
517 | \&\f(CW\*(C`LIBEV_FLAGS\*(C'\fR. Otherwise (the default), this environment variable will |
548 | \&\f(CW\*(C`LIBEV_FLAGS\*(C'\fR. Otherwise (the default), this environment variable will |
518 | override the flags completely if it is found in the environment. This is |
549 | override the flags completely if it is found in the environment. This is |
519 | useful to try out specific backends to test their performance, or to work |
550 | useful to try out specific backends to test their performance, to work |
520 | around bugs. |
551 | around bugs, or to make libev threadsafe (accessing environment variables |
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552 | cannot be done in a threadsafe way, but usually it works if no other |
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553 | thread modifies them). |
521 | .ie n .IP """EVFLAG_FORKCHECK""" 4 |
554 | .ie n .IP """EVFLAG_FORKCHECK""" 4 |
522 | .el .IP "\f(CWEVFLAG_FORKCHECK\fR" 4 |
555 | .el .IP "\f(CWEVFLAG_FORKCHECK\fR" 4 |
523 | .IX Item "EVFLAG_FORKCHECK" |
556 | .IX Item "EVFLAG_FORKCHECK" |
524 | Instead of calling \f(CW\*(C`ev_loop_fork\*(C'\fR manually after a fork, you can also |
557 | Instead of calling \f(CW\*(C`ev_loop_fork\*(C'\fR manually after a fork, you can also |
525 | make libev check for a fork in each iteration by enabling this flag. |
558 | make libev check for a fork in each iteration by enabling this flag. |
526 | .Sp |
559 | .Sp |
527 | This works by calling \f(CW\*(C`getpid ()\*(C'\fR on every iteration of the loop, |
560 | This works by calling \f(CW\*(C`getpid ()\*(C'\fR on every iteration of the loop, |
528 | and thus this might slow down your event loop if you do a lot of loop |
561 | and thus this might slow down your event loop if you do a lot of loop |
529 | iterations and little real work, but is usually not noticeable (on my |
562 | iterations and little real work, but is usually not noticeable (on my |
530 | GNU/Linux system for example, \f(CW\*(C`getpid\*(C'\fR is actually a simple 5\-insn sequence |
563 | GNU/Linux system for example, \f(CW\*(C`getpid\*(C'\fR is actually a simple 5\-insn |
531 | without a system call and thus \fIvery\fR fast, but my GNU/Linux system also has |
564 | sequence without a system call and thus \fIvery\fR fast, but my GNU/Linux |
532 | \&\f(CW\*(C`pthread_atfork\*(C'\fR which is even faster). |
565 | system also has \f(CW\*(C`pthread_atfork\*(C'\fR which is even faster). (Update: glibc |
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566 | versions 2.25 apparently removed the \f(CW\*(C`getpid\*(C'\fR optimisation again). |
533 | .Sp |
567 | .Sp |
534 | The big advantage of this flag is that you can forget about fork (and |
568 | The big advantage of this flag is that you can forget about fork (and |
535 | forget about forgetting to tell libev about forking) when you use this |
569 | forget about forgetting to tell libev about forking, although you still |
536 | flag. |
570 | have to ignore \f(CW\*(C`SIGPIPE\*(C'\fR) when you use this flag. |
537 | .Sp |
571 | .Sp |
538 | This flag setting cannot be overridden or specified in the \f(CW\*(C`LIBEV_FLAGS\*(C'\fR |
572 | This flag setting cannot be overridden or specified in the \f(CW\*(C`LIBEV_FLAGS\*(C'\fR |
539 | environment variable. |
573 | environment variable. |
540 | .ie n .IP """EVFLAG_NOINOTIFY""" 4 |
574 | .ie n .IP """EVFLAG_NOINOTIFY""" 4 |
541 | .el .IP "\f(CWEVFLAG_NOINOTIFY\fR" 4 |
575 | .el .IP "\f(CWEVFLAG_NOINOTIFY\fR" 4 |
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572 | \&\f(CW\*(C`sigprocmask\*(C'\fR, whose behaviour is officially unspecified. |
606 | \&\f(CW\*(C`sigprocmask\*(C'\fR, whose behaviour is officially unspecified. |
573 | .Sp |
607 | .Sp |
574 | This flag's behaviour will become the default in future versions of libev. |
608 | This flag's behaviour will become the default in future versions of libev. |
575 | .ie n .IP """EVBACKEND_SELECT"" (value 1, portable select backend)" 4 |
609 | .ie n .IP """EVBACKEND_SELECT"" (value 1, portable select backend)" 4 |
576 | .el .IP "\f(CWEVBACKEND_SELECT\fR (value 1, portable select backend)" 4 |
610 | .el .IP "\f(CWEVBACKEND_SELECT\fR (value 1, portable select backend)" 4 |
577 | .IX Item "EVBACKEND_SELECT (value 1, portable select backend)" |
611 | .IX Item "EVBACKEND_SELECT (value 1, portable select backend)" |
578 | This is your standard \fIselect\fR\|(2) backend. Not \fIcompletely\fR standard, as |
612 | This is your standard \fBselect\fR\|(2) backend. Not \fIcompletely\fR standard, as |
579 | libev tries to roll its own fd_set with no limits on the number of fds, |
613 | libev tries to roll its own fd_set with no limits on the number of fds, |
580 | but if that fails, expect a fairly low limit on the number of fds when |
614 | but if that fails, expect a fairly low limit on the number of fds when |
581 | using this backend. It doesn't scale too well (O(highest_fd)), but its |
615 | using this backend. It doesn't scale too well (O(highest_fd)), but its |
582 | usually the fastest backend for a low number of (low-numbered :) fds. |
616 | usually the fastest backend for a low number of (low-numbered :) fds. |
583 | .Sp |
617 | .Sp |
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591 | This backend maps \f(CW\*(C`EV_READ\*(C'\fR to the \f(CW\*(C`readfds\*(C'\fR set and \f(CW\*(C`EV_WRITE\*(C'\fR to the |
625 | This backend maps \f(CW\*(C`EV_READ\*(C'\fR to the \f(CW\*(C`readfds\*(C'\fR set and \f(CW\*(C`EV_WRITE\*(C'\fR to the |
592 | \&\f(CW\*(C`writefds\*(C'\fR set (and to work around Microsoft Windows bugs, also onto the |
626 | \&\f(CW\*(C`writefds\*(C'\fR set (and to work around Microsoft Windows bugs, also onto the |
593 | \&\f(CW\*(C`exceptfds\*(C'\fR set on that platform). |
627 | \&\f(CW\*(C`exceptfds\*(C'\fR set on that platform). |
594 | .ie n .IP """EVBACKEND_POLL"" (value 2, poll backend, available everywhere except on windows)" 4 |
628 | .ie n .IP """EVBACKEND_POLL"" (value 2, poll backend, available everywhere except on windows)" 4 |
595 | .el .IP "\f(CWEVBACKEND_POLL\fR (value 2, poll backend, available everywhere except on windows)" 4 |
629 | .el .IP "\f(CWEVBACKEND_POLL\fR (value 2, poll backend, available everywhere except on windows)" 4 |
596 | .IX Item "EVBACKEND_POLL (value 2, poll backend, available everywhere except on windows)" |
630 | .IX Item "EVBACKEND_POLL (value 2, poll backend, available everywhere except on windows)" |
597 | And this is your standard \fIpoll\fR\|(2) backend. It's more complicated |
631 | And this is your standard \fBpoll\fR\|(2) backend. It's more complicated |
598 | than select, but handles sparse fds better and has no artificial |
632 | than select, but handles sparse fds better and has no artificial |
599 | limit on the number of fds you can use (except it will slow down |
633 | limit on the number of fds you can use (except it will slow down |
600 | considerably with a lot of inactive fds). It scales similarly to select, |
634 | considerably with a lot of inactive fds). It scales similarly to select, |
601 | i.e. O(total_fds). See the entry for \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR, above, for |
635 | i.e. O(total_fds). See the entry for \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR, above, for |
602 | performance tips. |
636 | performance tips. |
603 | .Sp |
637 | .Sp |
604 | This backend maps \f(CW\*(C`EV_READ\*(C'\fR to \f(CW\*(C`POLLIN | POLLERR | POLLHUP\*(C'\fR, and |
638 | This backend maps \f(CW\*(C`EV_READ\*(C'\fR to \f(CW\*(C`POLLIN | POLLERR | POLLHUP\*(C'\fR, and |
605 | \&\f(CW\*(C`EV_WRITE\*(C'\fR to \f(CW\*(C`POLLOUT | POLLERR | POLLHUP\*(C'\fR. |
639 | \&\f(CW\*(C`EV_WRITE\*(C'\fR to \f(CW\*(C`POLLOUT | POLLERR | POLLHUP\*(C'\fR. |
606 | .ie n .IP """EVBACKEND_EPOLL"" (value 4, Linux)" 4 |
640 | .ie n .IP """EVBACKEND_EPOLL"" (value 4, Linux)" 4 |
607 | .el .IP "\f(CWEVBACKEND_EPOLL\fR (value 4, Linux)" 4 |
641 | .el .IP "\f(CWEVBACKEND_EPOLL\fR (value 4, Linux)" 4 |
608 | .IX Item "EVBACKEND_EPOLL (value 4, Linux)" |
642 | .IX Item "EVBACKEND_EPOLL (value 4, Linux)" |
609 | Use the linux-specific \fIepoll\fR\|(7) interface (for both pre\- and post\-2.6.9 |
643 | Use the linux-specific \fBepoll\fR\|(7) interface (for both pre\- and post\-2.6.9 |
610 | kernels). |
644 | kernels). |
611 | .Sp |
645 | .Sp |
612 | For few fds, this backend is a bit little slower than poll and select, but |
646 | For few fds, this backend is a bit little slower than poll and select, but |
613 | it scales phenomenally better. While poll and select usually scale like |
647 | it scales phenomenally better. While poll and select usually scale like |
614 | O(total_fds) where total_fds is the total number of fds (or the highest |
648 | O(total_fds) where total_fds is the total number of fds (or the highest |
… | |
… | |
660 | All this means that, in practice, \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR can be as fast or |
694 | All this means that, in practice, \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR can be as fast or |
661 | faster than epoll for maybe up to a hundred file descriptors, depending on |
695 | faster than epoll for maybe up to a hundred file descriptors, depending on |
662 | the usage. So sad. |
696 | the usage. So sad. |
663 | .Sp |
697 | .Sp |
664 | While nominally embeddable in other event loops, this feature is broken in |
698 | While nominally embeddable in other event loops, this feature is broken in |
665 | all kernel versions tested so far. |
699 | a lot of kernel revisions, but probably(!) works in current versions. |
|
|
700 | .Sp |
|
|
701 | This backend maps \f(CW\*(C`EV_READ\*(C'\fR and \f(CW\*(C`EV_WRITE\*(C'\fR in the same way as |
|
|
702 | \&\f(CW\*(C`EVBACKEND_POLL\*(C'\fR. |
|
|
703 | .ie n .IP """EVBACKEND_LINUXAIO"" (value 64, Linux)" 4 |
|
|
704 | .el .IP "\f(CWEVBACKEND_LINUXAIO\fR (value 64, Linux)" 4 |
|
|
705 | .IX Item "EVBACKEND_LINUXAIO (value 64, Linux)" |
|
|
706 | Use the linux-specific linux aio (\fInot\fR \f(CWaio(7)\fR) event interface |
|
|
707 | available in post\-4.18 kernels. |
|
|
708 | .Sp |
|
|
709 | If this backend works for you (as of this writing, it was very |
|
|
710 | experimental and only supports a subset of file types), it is the best |
|
|
711 | event interface available on linux and might be well worth it enabling it |
|
|
712 | \&\- if it isn't available in your kernel this will be detected and another |
|
|
713 | backend will be chosen. |
|
|
714 | .Sp |
|
|
715 | This backend can batch oneshot requests and uses a user-space ring buffer |
|
|
716 | to receive events. It also doesn't suffer from most of the design problems |
|
|
717 | of epoll (such as not being able to remove event sources from the epoll |
|
|
718 | set), and generally sounds too good to be true. Because, this being the |
|
|
719 | linux kernel, of course it suffers from a whole new set of limitations. |
|
|
720 | .Sp |
|
|
721 | For one, it is not easily embeddable (but probably could be done using |
|
|
722 | an event fd at some extra overhead). It also is subject to various |
|
|
723 | arbitrary limits that can be configured in \fI/proc/sys/fs/aio\-max\-nr\fR |
|
|
724 | and \fI/proc/sys/fs/aio\-nr\fR), which could lead to it being skipped during |
|
|
725 | initialisation. |
|
|
726 | .Sp |
|
|
727 | Most problematic in practise, however, is that, like kqueue, it requires |
|
|
728 | special support from drivers, and, not surprisingly, not all drivers |
|
|
729 | implement it. For example, in linux 4.19, tcp sockets, pipes, event fds, |
|
|
730 | files, \fI/dev/null\fR and a few others are supported, but ttys are not, so |
|
|
731 | this is not (yet?) a generic event polling interface but is probably still |
|
|
732 | be very useful in a web server or similar program. |
666 | .Sp |
733 | .Sp |
667 | This backend maps \f(CW\*(C`EV_READ\*(C'\fR and \f(CW\*(C`EV_WRITE\*(C'\fR in the same way as |
734 | This backend maps \f(CW\*(C`EV_READ\*(C'\fR and \f(CW\*(C`EV_WRITE\*(C'\fR in the same way as |
668 | \&\f(CW\*(C`EVBACKEND_POLL\*(C'\fR. |
735 | \&\f(CW\*(C`EVBACKEND_POLL\*(C'\fR. |
669 | .ie n .IP """EVBACKEND_KQUEUE"" (value 8, most \s-1BSD\s0 clones)" 4 |
736 | .ie n .IP """EVBACKEND_KQUEUE"" (value 8, most \s-1BSD\s0 clones)" 4 |
670 | .el .IP "\f(CWEVBACKEND_KQUEUE\fR (value 8, most \s-1BSD\s0 clones)" 4 |
737 | .el .IP "\f(CWEVBACKEND_KQUEUE\fR (value 8, most \s-1BSD\s0 clones)" 4 |
671 | .IX Item "EVBACKEND_KQUEUE (value 8, most BSD clones)" |
738 | .IX Item "EVBACKEND_KQUEUE (value 8, most BSD clones)" |
672 | Kqueue deserves special mention, as at the time of this writing, it |
739 | Kqueue deserves special mention, as at the time of this writing, it |
673 | was broken on all BSDs except NetBSD (usually it doesn't work reliably |
740 | was broken on all BSDs except NetBSD (usually it doesn't work reliably |
674 | with anything but sockets and pipes, except on Darwin, where of course |
741 | with anything but sockets and pipes, except on Darwin, where of course |
675 | it's completely useless). Unlike epoll, however, whose brokenness |
742 | it's completely useless). Unlike epoll, however, whose brokenness |
676 | is by design, these kqueue bugs can (and eventually will) be fixed |
743 | is by design, these kqueue bugs can (and eventually will) be fixed |
… | |
… | |
687 | kernel is more efficient (which says nothing about its actual speed, of |
754 | kernel is more efficient (which says nothing about its actual speed, of |
688 | course). While stopping, setting and starting an I/O watcher does never |
755 | course). While stopping, setting and starting an I/O watcher does never |
689 | cause an extra system call as with \f(CW\*(C`EVBACKEND_EPOLL\*(C'\fR, it still adds up to |
756 | cause an extra system call as with \f(CW\*(C`EVBACKEND_EPOLL\*(C'\fR, it still adds up to |
690 | two event changes per incident. Support for \f(CW\*(C`fork ()\*(C'\fR is very bad (you |
757 | two event changes per incident. Support for \f(CW\*(C`fork ()\*(C'\fR is very bad (you |
691 | might have to leak fd's on fork, but it's more sane than epoll) and it |
758 | might have to leak fd's on fork, but it's more sane than epoll) and it |
692 | drops fds silently in similarly hard-to-detect cases |
759 | drops fds silently in similarly hard-to-detect cases. |
693 | .Sp |
760 | .Sp |
694 | This backend usually performs well under most conditions. |
761 | This backend usually performs well under most conditions. |
695 | .Sp |
762 | .Sp |
696 | While nominally embeddable in other event loops, this doesn't work |
763 | While nominally embeddable in other event loops, this doesn't work |
697 | everywhere, so you might need to test for this. And since it is broken |
764 | everywhere, so you might need to test for this. And since it is broken |
698 | almost everywhere, you should only use it when you have a lot of sockets |
765 | almost everywhere, you should only use it when you have a lot of sockets |
699 | (for which it usually works), by embedding it into another event loop |
766 | (for which it usually works), by embedding it into another event loop |
700 | (e.g. \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR or \f(CW\*(C`EVBACKEND_POLL\*(C'\fR (but \f(CW\*(C`poll\*(C'\fR is of course |
767 | (e.g. \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR or \f(CW\*(C`EVBACKEND_POLL\*(C'\fR (but \f(CW\*(C`poll\*(C'\fR is of course |
701 | also broken on \s-1OS\s0 X)) and, did I mention it, using it only for sockets. |
768 | also broken on \s-1OS X\s0)) and, did I mention it, using it only for sockets. |
702 | .Sp |
769 | .Sp |
703 | This backend maps \f(CW\*(C`EV_READ\*(C'\fR into an \f(CW\*(C`EVFILT_READ\*(C'\fR kevent with |
770 | This backend maps \f(CW\*(C`EV_READ\*(C'\fR into an \f(CW\*(C`EVFILT_READ\*(C'\fR kevent with |
704 | \&\f(CW\*(C`NOTE_EOF\*(C'\fR, and \f(CW\*(C`EV_WRITE\*(C'\fR into an \f(CW\*(C`EVFILT_WRITE\*(C'\fR kevent with |
771 | \&\f(CW\*(C`NOTE_EOF\*(C'\fR, and \f(CW\*(C`EV_WRITE\*(C'\fR into an \f(CW\*(C`EVFILT_WRITE\*(C'\fR kevent with |
705 | \&\f(CW\*(C`NOTE_EOF\*(C'\fR. |
772 | \&\f(CW\*(C`NOTE_EOF\*(C'\fR. |
706 | .ie n .IP """EVBACKEND_DEVPOLL"" (value 16, Solaris 8)" 4 |
773 | .ie n .IP """EVBACKEND_DEVPOLL"" (value 16, Solaris 8)" 4 |
… | |
… | |
710 | implementation). According to reports, \f(CW\*(C`/dev/poll\*(C'\fR only supports sockets |
777 | implementation). According to reports, \f(CW\*(C`/dev/poll\*(C'\fR only supports sockets |
711 | and is not embeddable, which would limit the usefulness of this backend |
778 | and is not embeddable, which would limit the usefulness of this backend |
712 | immensely. |
779 | immensely. |
713 | .ie n .IP """EVBACKEND_PORT"" (value 32, Solaris 10)" 4 |
780 | .ie n .IP """EVBACKEND_PORT"" (value 32, Solaris 10)" 4 |
714 | .el .IP "\f(CWEVBACKEND_PORT\fR (value 32, Solaris 10)" 4 |
781 | .el .IP "\f(CWEVBACKEND_PORT\fR (value 32, Solaris 10)" 4 |
715 | .IX Item "EVBACKEND_PORT (value 32, Solaris 10)" |
782 | .IX Item "EVBACKEND_PORT (value 32, Solaris 10)" |
716 | This uses the Solaris 10 event port mechanism. As with everything on Solaris, |
783 | This uses the Solaris 10 event port mechanism. As with everything on Solaris, |
717 | it's really slow, but it still scales very well (O(active_fds)). |
784 | it's really slow, but it still scales very well (O(active_fds)). |
718 | .Sp |
785 | .Sp |
719 | While this backend scales well, it requires one system call per active |
786 | While this backend scales well, it requires one system call per active |
720 | file descriptor per loop iteration. For small and medium numbers of file |
787 | file descriptor per loop iteration. For small and medium numbers of file |
… | |
… | |
774 | used if available. |
841 | used if available. |
775 | .Sp |
842 | .Sp |
776 | .Vb 1 |
843 | .Vb 1 |
777 | \& struct ev_loop *loop = ev_loop_new (ev_recommended_backends () | EVBACKEND_KQUEUE); |
844 | \& struct ev_loop *loop = ev_loop_new (ev_recommended_backends () | EVBACKEND_KQUEUE); |
778 | .Ve |
845 | .Ve |
|
|
846 | .Sp |
|
|
847 | Example: Similarly, on linux, you mgiht want to take advantage of the |
|
|
848 | linux aio backend if possible, but fall back to something else if that |
|
|
849 | isn't available. |
|
|
850 | .Sp |
|
|
851 | .Vb 1 |
|
|
852 | \& struct ev_loop *loop = ev_loop_new (ev_recommended_backends () | EVBACKEND_LINUXAIO); |
|
|
853 | .Ve |
779 | .RE |
854 | .RE |
780 | .IP "ev_loop_destroy (loop)" 4 |
855 | .IP "ev_loop_destroy (loop)" 4 |
781 | .IX Item "ev_loop_destroy (loop)" |
856 | .IX Item "ev_loop_destroy (loop)" |
782 | Destroys an event loop object (frees all memory and kernel state |
857 | Destroys an event loop object (frees all memory and kernel state |
783 | etc.). None of the active event watchers will be stopped in the normal |
858 | etc.). None of the active event watchers will be stopped in the normal |
… | |
… | |
799 | except in the rare occasion where you really need to free its resources. |
874 | except in the rare occasion where you really need to free its resources. |
800 | If you need dynamically allocated loops it is better to use \f(CW\*(C`ev_loop_new\*(C'\fR |
875 | If you need dynamically allocated loops it is better to use \f(CW\*(C`ev_loop_new\*(C'\fR |
801 | and \f(CW\*(C`ev_loop_destroy\*(C'\fR. |
876 | and \f(CW\*(C`ev_loop_destroy\*(C'\fR. |
802 | .IP "ev_loop_fork (loop)" 4 |
877 | .IP "ev_loop_fork (loop)" 4 |
803 | .IX Item "ev_loop_fork (loop)" |
878 | .IX Item "ev_loop_fork (loop)" |
804 | This function sets a flag that causes subsequent \f(CW\*(C`ev_run\*(C'\fR iterations to |
879 | This function sets a flag that causes subsequent \f(CW\*(C`ev_run\*(C'\fR iterations |
805 | reinitialise the kernel state for backends that have one. Despite the |
880 | to reinitialise the kernel state for backends that have one. Despite |
806 | name, you can call it anytime, but it makes most sense after forking, in |
881 | the name, you can call it anytime you are allowed to start or stop |
807 | the child process. You \fImust\fR call it (or use \f(CW\*(C`EVFLAG_FORKCHECK\*(C'\fR) in the |
882 | watchers (except inside an \f(CW\*(C`ev_prepare\*(C'\fR callback), but it makes most |
808 | child before resuming or calling \f(CW\*(C`ev_run\*(C'\fR. |
883 | sense after forking, in the child process. You \fImust\fR call it (or use |
|
|
884 | \&\f(CW\*(C`EVFLAG_FORKCHECK\*(C'\fR) in the child before resuming or calling \f(CW\*(C`ev_run\*(C'\fR. |
809 | .Sp |
885 | .Sp |
|
|
886 | In addition, if you want to reuse a loop (via this function or |
|
|
887 | \&\f(CW\*(C`EVFLAG_FORKCHECK\*(C'\fR), you \fIalso\fR have to ignore \f(CW\*(C`SIGPIPE\*(C'\fR. |
|
|
888 | .Sp |
810 | Again, you \fIhave\fR to call it on \fIany\fR loop that you want to re-use after |
889 | Again, you \fIhave\fR to call it on \fIany\fR loop that you want to re-use after |
811 | a fork, \fIeven if you do not plan to use the loop in the parent\fR. This is |
890 | a fork, \fIeven if you do not plan to use the loop in the parent\fR. This is |
812 | because some kernel interfaces *cough* \fIkqueue\fR *cough* do funny things |
891 | because some kernel interfaces *cough* \fIkqueue\fR *cough* do funny things |
813 | during fork. |
892 | during fork. |
814 | .Sp |
893 | .Sp |
815 | On the other hand, you only need to call this function in the child |
894 | On the other hand, you only need to call this function in the child |
… | |
… | |
1299 | .PD 0 |
1378 | .PD 0 |
1300 | .ie n .IP """EV_CHECK""" 4 |
1379 | .ie n .IP """EV_CHECK""" 4 |
1301 | .el .IP "\f(CWEV_CHECK\fR" 4 |
1380 | .el .IP "\f(CWEV_CHECK\fR" 4 |
1302 | .IX Item "EV_CHECK" |
1381 | .IX Item "EV_CHECK" |
1303 | .PD |
1382 | .PD |
1304 | All \f(CW\*(C`ev_prepare\*(C'\fR watchers are invoked just \fIbefore\fR \f(CW\*(C`ev_run\*(C'\fR starts |
1383 | All \f(CW\*(C`ev_prepare\*(C'\fR watchers are invoked just \fIbefore\fR \f(CW\*(C`ev_run\*(C'\fR starts to |
1305 | to gather new events, and all \f(CW\*(C`ev_check\*(C'\fR watchers are invoked just after |
1384 | gather new events, and all \f(CW\*(C`ev_check\*(C'\fR watchers are queued (not invoked) |
1306 | \&\f(CW\*(C`ev_run\*(C'\fR has gathered them, but before it invokes any callbacks for any |
1385 | just after \f(CW\*(C`ev_run\*(C'\fR has gathered them, but before it queues any callbacks |
|
|
1386 | for any received events. That means \f(CW\*(C`ev_prepare\*(C'\fR watchers are the last |
|
|
1387 | watchers invoked before the event loop sleeps or polls for new events, and |
|
|
1388 | \&\f(CW\*(C`ev_check\*(C'\fR watchers will be invoked before any other watchers of the same |
|
|
1389 | or lower priority within an event loop iteration. |
|
|
1390 | .Sp |
1307 | received events. Callbacks of both watcher types can start and stop as |
1391 | Callbacks of both watcher types can start and stop as many watchers as |
1308 | many watchers as they want, and all of them will be taken into account |
1392 | they want, and all of them will be taken into account (for example, a |
1309 | (for example, a \f(CW\*(C`ev_prepare\*(C'\fR watcher might start an idle watcher to keep |
1393 | \&\f(CW\*(C`ev_prepare\*(C'\fR watcher might start an idle watcher to keep \f(CW\*(C`ev_run\*(C'\fR from |
1310 | \&\f(CW\*(C`ev_run\*(C'\fR from blocking). |
1394 | blocking). |
1311 | .ie n .IP """EV_EMBED""" 4 |
1395 | .ie n .IP """EV_EMBED""" 4 |
1312 | .el .IP "\f(CWEV_EMBED\fR" 4 |
1396 | .el .IP "\f(CWEV_EMBED\fR" 4 |
1313 | .IX Item "EV_EMBED" |
1397 | .IX Item "EV_EMBED" |
1314 | The embedded event loop specified in the \f(CW\*(C`ev_embed\*(C'\fR watcher needs attention. |
1398 | The embedded event loop specified in the \f(CW\*(C`ev_embed\*(C'\fR watcher needs attention. |
1315 | .ie n .IP """EV_FORK""" 4 |
1399 | .ie n .IP """EV_FORK""" 4 |
… | |
… | |
1344 | bug in your program. |
1428 | bug in your program. |
1345 | .Sp |
1429 | .Sp |
1346 | Libev will usually signal a few \*(L"dummy\*(R" events together with an error, for |
1430 | Libev will usually signal a few \*(L"dummy\*(R" events together with an error, for |
1347 | example it might indicate that a fd is readable or writable, and if your |
1431 | example it might indicate that a fd is readable or writable, and if your |
1348 | callbacks is well-written it can just attempt the operation and cope with |
1432 | callbacks is well-written it can just attempt the operation and cope with |
1349 | the error from \fIread()\fR or \fIwrite()\fR. This will not work in multi-threaded |
1433 | the error from \fBread()\fR or \fBwrite()\fR. This will not work in multi-threaded |
1350 | programs, though, as the fd could already be closed and reused for another |
1434 | programs, though, as the fd could already be closed and reused for another |
1351 | thing, so beware. |
1435 | thing, so beware. |
1352 | .SS "\s-1GENERIC\s0 \s-1WATCHER\s0 \s-1FUNCTIONS\s0" |
1436 | .SS "\s-1GENERIC WATCHER FUNCTIONS\s0" |
1353 | .IX Subsection "GENERIC WATCHER FUNCTIONS" |
1437 | .IX Subsection "GENERIC WATCHER FUNCTIONS" |
1354 | .ie n .IP """ev_init"" (ev_TYPE *watcher, callback)" 4 |
1438 | .ie n .IP """ev_init"" (ev_TYPE *watcher, callback)" 4 |
1355 | .el .IP "\f(CWev_init\fR (ev_TYPE *watcher, callback)" 4 |
1439 | .el .IP "\f(CWev_init\fR (ev_TYPE *watcher, callback)" 4 |
1356 | .IX Item "ev_init (ev_TYPE *watcher, callback)" |
1440 | .IX Item "ev_init (ev_TYPE *watcher, callback)" |
1357 | This macro initialises the generic portion of a watcher. The contents |
1441 | This macro initialises the generic portion of a watcher. The contents |
… | |
… | |
1436 | make sure the watcher is available to libev (e.g. you cannot \f(CW\*(C`free ()\*(C'\fR |
1520 | make sure the watcher is available to libev (e.g. you cannot \f(CW\*(C`free ()\*(C'\fR |
1437 | it). |
1521 | it). |
1438 | .IP "callback ev_cb (ev_TYPE *watcher)" 4 |
1522 | .IP "callback ev_cb (ev_TYPE *watcher)" 4 |
1439 | .IX Item "callback ev_cb (ev_TYPE *watcher)" |
1523 | .IX Item "callback ev_cb (ev_TYPE *watcher)" |
1440 | Returns the callback currently set on the watcher. |
1524 | Returns the callback currently set on the watcher. |
1441 | .IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 |
1525 | .IP "ev_set_cb (ev_TYPE *watcher, callback)" 4 |
1442 | .IX Item "ev_cb_set (ev_TYPE *watcher, callback)" |
1526 | .IX Item "ev_set_cb (ev_TYPE *watcher, callback)" |
1443 | Change the callback. You can change the callback at virtually any time |
1527 | Change the callback. You can change the callback at virtually any time |
1444 | (modulo threads). |
1528 | (modulo threads). |
1445 | .IP "ev_set_priority (ev_TYPE *watcher, int priority)" 4 |
1529 | .IP "ev_set_priority (ev_TYPE *watcher, int priority)" 4 |
1446 | .IX Item "ev_set_priority (ev_TYPE *watcher, int priority)" |
1530 | .IX Item "ev_set_priority (ev_TYPE *watcher, int priority)" |
1447 | .PD 0 |
1531 | .PD 0 |
… | |
… | |
1465 | or might not have been clamped to the valid range. |
1549 | or might not have been clamped to the valid range. |
1466 | .Sp |
1550 | .Sp |
1467 | The default priority used by watchers when no priority has been set is |
1551 | The default priority used by watchers when no priority has been set is |
1468 | always \f(CW0\fR, which is supposed to not be too high and not be too low :). |
1552 | always \f(CW0\fR, which is supposed to not be too high and not be too low :). |
1469 | .Sp |
1553 | .Sp |
1470 | See \*(L"\s-1WATCHER\s0 \s-1PRIORITY\s0 \s-1MODELS\s0\*(R", below, for a more thorough treatment of |
1554 | See \*(L"\s-1WATCHER PRIORITY MODELS\*(R"\s0, below, for a more thorough treatment of |
1471 | priorities. |
1555 | priorities. |
1472 | .IP "ev_invoke (loop, ev_TYPE *watcher, int revents)" 4 |
1556 | .IP "ev_invoke (loop, ev_TYPE *watcher, int revents)" 4 |
1473 | .IX Item "ev_invoke (loop, ev_TYPE *watcher, int revents)" |
1557 | .IX Item "ev_invoke (loop, ev_TYPE *watcher, int revents)" |
1474 | 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 |
1558 | 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 |
1475 | \&\f(CW\*(C`loop\*(C'\fR nor \f(CW\*(C`revents\*(C'\fR need to be valid as long as the watcher callback |
1559 | \&\f(CW\*(C`loop\*(C'\fR nor \f(CW\*(C`revents\*(C'\fR need to be valid as long as the watcher callback |
… | |
… | |
1495 | not started in the first place. |
1579 | not started in the first place. |
1496 | .Sp |
1580 | .Sp |
1497 | See also \f(CW\*(C`ev_feed_fd_event\*(C'\fR and \f(CW\*(C`ev_feed_signal_event\*(C'\fR for related |
1581 | See also \f(CW\*(C`ev_feed_fd_event\*(C'\fR and \f(CW\*(C`ev_feed_signal_event\*(C'\fR for related |
1498 | functions that do not need a watcher. |
1582 | functions that do not need a watcher. |
1499 | .PP |
1583 | .PP |
1500 | See also the \*(L"\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0\*(R" and \*(L"\s-1BUILDING\s0 \s-1YOUR\s0 |
1584 | See also the \*(L"\s-1ASSOCIATING CUSTOM DATA WITH A WATCHER\*(R"\s0 and \*(L"\s-1BUILDING YOUR |
1501 | \&\s-1OWN\s0 \s-1COMPOSITE\s0 \s-1WATCHERS\s0\*(R" idioms. |
1585 | OWN COMPOSITE WATCHERS\*(R"\s0 idioms. |
1502 | .SS "\s-1WATCHER\s0 \s-1STATES\s0" |
1586 | .SS "\s-1WATCHER STATES\s0" |
1503 | .IX Subsection "WATCHER STATES" |
1587 | .IX Subsection "WATCHER STATES" |
1504 | There are various watcher states mentioned throughout this manual \- |
1588 | There are various watcher states mentioned throughout this manual \- |
1505 | active, pending and so on. In this section these states and the rules to |
1589 | active, pending and so on. In this section these states and the rules to |
1506 | transition between them will be described in more detail \- and while these |
1590 | transition between them will be described in more detail \- and while these |
1507 | rules might look complicated, they usually do \*(L"the right thing\*(R". |
1591 | rules might look complicated, they usually do \*(L"the right thing\*(R". |
1508 | .IP "initialiased" 4 |
1592 | .IP "initialised" 4 |
1509 | .IX Item "initialiased" |
1593 | .IX Item "initialised" |
1510 | Before a watcher can be registered with the event loop it has to be |
1594 | Before a watcher can be registered with the event loop it has to be |
1511 | initialised. This can be done with a call to \f(CW\*(C`ev_TYPE_init\*(C'\fR, or calls to |
1595 | initialised. This can be done with a call to \f(CW\*(C`ev_TYPE_init\*(C'\fR, or calls to |
1512 | \&\f(CW\*(C`ev_init\*(C'\fR followed by the watcher-specific \f(CW\*(C`ev_TYPE_set\*(C'\fR function. |
1596 | \&\f(CW\*(C`ev_init\*(C'\fR followed by the watcher-specific \f(CW\*(C`ev_TYPE_set\*(C'\fR function. |
1513 | .Sp |
1597 | .Sp |
1514 | In this state it is simply some block of memory that is suitable for |
1598 | In this state it is simply some block of memory that is suitable for |
… | |
… | |
1550 | .Sp |
1634 | .Sp |
1551 | While stopped (and not pending) the watcher is essentially in the |
1635 | While stopped (and not pending) the watcher is essentially in the |
1552 | initialised state, that is, it can be reused, moved, modified in any way |
1636 | initialised state, that is, it can be reused, moved, modified in any way |
1553 | you wish (but when you trash the memory block, you need to \f(CW\*(C`ev_TYPE_init\*(C'\fR |
1637 | you wish (but when you trash the memory block, you need to \f(CW\*(C`ev_TYPE_init\*(C'\fR |
1554 | it again). |
1638 | it again). |
1555 | .SS "\s-1WATCHER\s0 \s-1PRIORITY\s0 \s-1MODELS\s0" |
1639 | .SS "\s-1WATCHER PRIORITY MODELS\s0" |
1556 | .IX Subsection "WATCHER PRIORITY MODELS" |
1640 | .IX Subsection "WATCHER PRIORITY MODELS" |
1557 | Many event loops support \fIwatcher priorities\fR, which are usually small |
1641 | Many event loops support \fIwatcher priorities\fR, which are usually small |
1558 | integers that influence the ordering of event callback invocation |
1642 | integers that influence the ordering of event callback invocation |
1559 | between watchers in some way, all else being equal. |
1643 | between watchers in some way, all else being equal. |
1560 | .PP |
1644 | .PP |
… | |
… | |
1705 | But really, best use non-blocking mode. |
1789 | But really, best use non-blocking mode. |
1706 | .PP |
1790 | .PP |
1707 | \fIThe special problem of disappearing file descriptors\fR |
1791 | \fIThe special problem of disappearing file descriptors\fR |
1708 | .IX Subsection "The special problem of disappearing file descriptors" |
1792 | .IX Subsection "The special problem of disappearing file descriptors" |
1709 | .PP |
1793 | .PP |
1710 | Some backends (e.g. kqueue, epoll) need to be told about closing a file |
1794 | Some backends (e.g. kqueue, epoll, linuxaio) need to be told about closing |
1711 | descriptor (either due to calling \f(CW\*(C`close\*(C'\fR explicitly or any other means, |
1795 | a file descriptor (either due to calling \f(CW\*(C`close\*(C'\fR explicitly or any other |
1712 | such as \f(CW\*(C`dup2\*(C'\fR). The reason is that you register interest in some file |
1796 | means, such as \f(CW\*(C`dup2\*(C'\fR). The reason is that you register interest in some |
1713 | descriptor, but when it goes away, the operating system will silently drop |
1797 | file descriptor, but when it goes away, the operating system will silently |
1714 | this interest. If another file descriptor with the same number then is |
1798 | drop this interest. If another file descriptor with the same number then |
1715 | registered with libev, there is no efficient way to see that this is, in |
1799 | is registered with libev, there is no efficient way to see that this is, |
1716 | fact, a different file descriptor. |
1800 | in fact, a different file descriptor. |
1717 | .PP |
1801 | .PP |
1718 | To avoid having to explicitly tell libev about such cases, libev follows |
1802 | To avoid having to explicitly tell libev about such cases, libev follows |
1719 | the following policy: Each time \f(CW\*(C`ev_io_set\*(C'\fR is being called, libev |
1803 | the following policy: Each time \f(CW\*(C`ev_io_set\*(C'\fR is being called, libev |
1720 | will assume that this is potentially a new file descriptor, otherwise |
1804 | will assume that this is potentially a new file descriptor, otherwise |
1721 | it is assumed that the file descriptor stays the same. That means that |
1805 | it is assumed that the file descriptor stays the same. That means that |
… | |
… | |
1758 | wish to read \- you would first have to request some data. |
1842 | wish to read \- you would first have to request some data. |
1759 | .PP |
1843 | .PP |
1760 | Since files are typically not-so-well supported by advanced notification |
1844 | Since files are typically not-so-well supported by advanced notification |
1761 | mechanism, libev tries hard to emulate \s-1POSIX\s0 behaviour with respect |
1845 | mechanism, libev tries hard to emulate \s-1POSIX\s0 behaviour with respect |
1762 | to files, even though you should not use it. The reason for this is |
1846 | to files, even though you should not use it. The reason for this is |
1763 | convenience: sometimes you want to watch \s-1STDIN\s0 or \s-1STDOUT\s0, which is |
1847 | convenience: sometimes you want to watch \s-1STDIN\s0 or \s-1STDOUT,\s0 which is |
1764 | usually a tty, often a pipe, but also sometimes files or special devices |
1848 | usually a tty, often a pipe, but also sometimes files or special devices |
1765 | (for example, \f(CW\*(C`epoll\*(C'\fR on Linux works with \fI/dev/random\fR but not with |
1849 | (for example, \f(CW\*(C`epoll\*(C'\fR on Linux works with \fI/dev/random\fR but not with |
1766 | \&\fI/dev/urandom\fR), and even though the file might better be served with |
1850 | \&\fI/dev/urandom\fR), and even though the file might better be served with |
1767 | asynchronous I/O instead of with non-blocking I/O, it is still useful when |
1851 | asynchronous I/O instead of with non-blocking I/O, it is still useful when |
1768 | it \*(L"just works\*(R" instead of freezing. |
1852 | it \*(L"just works\*(R" instead of freezing. |
1769 | .PP |
1853 | .PP |
1770 | So avoid file descriptors pointing to files when you know it (e.g. use |
1854 | So avoid file descriptors pointing to files when you know it (e.g. use |
1771 | libeio), but use them when it is convenient, e.g. for \s-1STDIN/STDOUT\s0, or |
1855 | libeio), but use them when it is convenient, e.g. for \s-1STDIN/STDOUT,\s0 or |
1772 | when you rarely read from a file instead of from a socket, and want to |
1856 | when you rarely read from a file instead of from a socket, and want to |
1773 | reuse the same code path. |
1857 | reuse the same code path. |
1774 | .PP |
1858 | .PP |
1775 | \fIThe special problem of fork\fR |
1859 | \fIThe special problem of fork\fR |
1776 | .IX Subsection "The special problem of fork" |
1860 | .IX Subsection "The special problem of fork" |
1777 | .PP |
1861 | .PP |
1778 | Some backends (epoll, kqueue) do not support \f(CW\*(C`fork ()\*(C'\fR at all or exhibit |
1862 | Some backends (epoll, kqueue, probably linuxaio) do not support \f(CW\*(C`fork ()\*(C'\fR |
1779 | useless behaviour. Libev fully supports fork, but needs to be told about |
1863 | at all or exhibit useless behaviour. Libev fully supports fork, but needs |
1780 | it in the child if you want to continue to use it in the child. |
1864 | to be told about it in the child if you want to continue to use it in the |
|
|
1865 | child. |
1781 | .PP |
1866 | .PP |
1782 | To support fork in your child processes, you have to call \f(CW\*(C`ev_loop_fork |
1867 | To support fork in your child processes, you have to call \f(CW\*(C`ev_loop_fork |
1783 | ()\*(C'\fR after a fork in the child, enable \f(CW\*(C`EVFLAG_FORKCHECK\*(C'\fR, or resort to |
1868 | ()\*(C'\fR after a fork in the child, enable \f(CW\*(C`EVFLAG_FORKCHECK\*(C'\fR, or resort to |
1784 | \&\f(CW\*(C`EVBACKEND_SELECT\*(C'\fR or \f(CW\*(C`EVBACKEND_POLL\*(C'\fR. |
1869 | \&\f(CW\*(C`EVBACKEND_SELECT\*(C'\fR or \f(CW\*(C`EVBACKEND_POLL\*(C'\fR. |
1785 | .PP |
1870 | .PP |
1786 | \fIThe special problem of \s-1SIGPIPE\s0\fR |
1871 | \fIThe special problem of \s-1SIGPIPE\s0\fR |
1787 | .IX Subsection "The special problem of SIGPIPE" |
1872 | .IX Subsection "The special problem of SIGPIPE" |
1788 | .PP |
1873 | .PP |
1789 | While not really specific to libev, it is easy to forget about \f(CW\*(C`SIGPIPE\*(C'\fR: |
1874 | While not really specific to libev, it is easy to forget about \f(CW\*(C`SIGPIPE\*(C'\fR: |
1790 | when writing to a pipe whose other end has been closed, your program gets |
1875 | when writing to a pipe whose other end has been closed, your program gets |
1791 | sent a \s-1SIGPIPE\s0, which, by default, aborts your program. For most programs |
1876 | sent a \s-1SIGPIPE,\s0 which, by default, aborts your program. For most programs |
1792 | this is sensible behaviour, for daemons, this is usually undesirable. |
1877 | this is sensible behaviour, for daemons, this is usually undesirable. |
1793 | .PP |
1878 | .PP |
1794 | So when you encounter spurious, unexplained daemon exits, make sure you |
1879 | So when you encounter spurious, unexplained daemon exits, make sure you |
1795 | ignore \s-1SIGPIPE\s0 (and maybe make sure you log the exit status of your daemon |
1880 | ignore \s-1SIGPIPE\s0 (and maybe make sure you log the exit status of your daemon |
1796 | somewhere, as that would have given you a big clue). |
1881 | somewhere, as that would have given you a big clue). |
1797 | .PP |
1882 | .PP |
1798 | \fIThe special problem of \fIaccept()\fIing when you can't\fR |
1883 | \fIThe special problem of \f(BIaccept()\fIing when you can't\fR |
1799 | .IX Subsection "The special problem of accept()ing when you can't" |
1884 | .IX Subsection "The special problem of accept()ing when you can't" |
1800 | .PP |
1885 | .PP |
1801 | Many implementations of the \s-1POSIX\s0 \f(CW\*(C`accept\*(C'\fR function (for example, |
1886 | Many implementations of the \s-1POSIX\s0 \f(CW\*(C`accept\*(C'\fR function (for example, |
1802 | found in post\-2004 Linux) have the peculiar behaviour of not removing a |
1887 | found in post\-2004 Linux) have the peculiar behaviour of not removing a |
1803 | connection from the pending queue in all error cases. |
1888 | connection from the pending queue in all error cases. |
… | |
… | |
1994 | \& callback (EV_P_ ev_timer *w, int revents) |
2079 | \& callback (EV_P_ ev_timer *w, int revents) |
1995 | \& { |
2080 | \& { |
1996 | \& // calculate when the timeout would happen |
2081 | \& // calculate when the timeout would happen |
1997 | \& ev_tstamp after = last_activity \- ev_now (EV_A) + timeout; |
2082 | \& ev_tstamp after = last_activity \- ev_now (EV_A) + timeout; |
1998 | \& |
2083 | \& |
1999 | \& // if negative, it means we the timeout already occured |
2084 | \& // if negative, it means we the timeout already occurred |
2000 | \& if (after < 0.) |
2085 | \& if (after < 0.) |
2001 | \& { |
2086 | \& { |
2002 | \& // timeout occurred, take action |
2087 | \& // timeout occurred, take action |
2003 | \& } |
2088 | \& } |
2004 | \& else |
2089 | \& else |
… | |
… | |
2023 | .Sp |
2108 | .Sp |
2024 | Otherwise, we now the earliest time at which the timeout would trigger, |
2109 | Otherwise, we now the earliest time at which the timeout would trigger, |
2025 | and simply start the timer with this timeout value. |
2110 | and simply start the timer with this timeout value. |
2026 | .Sp |
2111 | .Sp |
2027 | In other words, each time the callback is invoked it will check whether |
2112 | In other words, each time the callback is invoked it will check whether |
2028 | the timeout cocured. If not, it will simply reschedule itself to check |
2113 | the timeout occurred. If not, it will simply reschedule itself to check |
2029 | again at the earliest time it could time out. Rinse. Repeat. |
2114 | again at the earliest time it could time out. Rinse. Repeat. |
2030 | .Sp |
2115 | .Sp |
2031 | This scheme causes more callback invocations (about one every 60 seconds |
2116 | This scheme causes more callback invocations (about one every 60 seconds |
2032 | minus half the average time between activity), but virtually no calls to |
2117 | minus half the average time between activity), but virtually no calls to |
2033 | libev to change the timeout. |
2118 | libev to change the timeout. |
… | |
… | |
2051 | \& last_activity = ev_now (EV_A); |
2136 | \& last_activity = ev_now (EV_A); |
2052 | .Ve |
2137 | .Ve |
2053 | .Sp |
2138 | .Sp |
2054 | When your timeout value changes, then the timeout can be changed by simply |
2139 | When your timeout value changes, then the timeout can be changed by simply |
2055 | providing a new value, stopping the timer and calling the callback, which |
2140 | providing a new value, stopping the timer and calling the callback, which |
2056 | will agaion do the right thing (for example, time out immediately :). |
2141 | will again do the right thing (for example, time out immediately :). |
2057 | .Sp |
2142 | .Sp |
2058 | .Vb 3 |
2143 | .Vb 3 |
2059 | \& timeout = new_value; |
2144 | \& timeout = new_value; |
2060 | \& ev_timer_stop (EV_A_ &timer); |
2145 | \& ev_timer_stop (EV_A_ &timer); |
2061 | \& callback (EV_A_ &timer, 0); |
2146 | \& callback (EV_A_ &timer, 0); |
… | |
… | |
2145 | .PP |
2230 | .PP |
2146 | The relative timeouts are calculated relative to the \f(CW\*(C`ev_now ()\*(C'\fR |
2231 | The relative timeouts are calculated relative to the \f(CW\*(C`ev_now ()\*(C'\fR |
2147 | time. This is usually the right thing as this timestamp refers to the time |
2232 | time. This is usually the right thing as this timestamp refers to the time |
2148 | of the event triggering whatever timeout you are modifying/starting. If |
2233 | of the event triggering whatever timeout you are modifying/starting. If |
2149 | you suspect event processing to be delayed and you \fIneed\fR to base the |
2234 | you suspect event processing to be delayed and you \fIneed\fR to base the |
2150 | timeout on the current time, use something like this to adjust for this: |
2235 | timeout on the current time, use something like the following to adjust |
|
|
2236 | for it: |
2151 | .PP |
2237 | .PP |
2152 | .Vb 1 |
2238 | .Vb 1 |
2153 | \& ev_timer_set (&timer, after + ev_now () \- ev_time (), 0.); |
2239 | \& ev_timer_set (&timer, after + (ev_time () \- ev_now ()), 0.); |
2154 | .Ve |
2240 | .Ve |
2155 | .PP |
2241 | .PP |
2156 | If the event loop is suspended for a long time, you can also force an |
2242 | If the event loop is suspended for a long time, you can also force an |
2157 | update of the time returned by \f(CW\*(C`ev_now ()\*(C'\fR by calling \f(CW\*(C`ev_now_update |
2243 | update of the time returned by \f(CW\*(C`ev_now ()\*(C'\fR by calling \f(CW\*(C`ev_now_update |
2158 | ()\*(C'\fR. |
2244 | ()\*(C'\fR, although that will push the event time of all outstanding events |
|
|
2245 | further into the future. |
2159 | .PP |
2246 | .PP |
2160 | \fIThe special problem of unsynchronised clocks\fR |
2247 | \fIThe special problem of unsynchronised clocks\fR |
2161 | .IX Subsection "The special problem of unsynchronised clocks" |
2248 | .IX Subsection "The special problem of unsynchronised clocks" |
2162 | .PP |
2249 | .PP |
2163 | Modern systems have a variety of clocks \- libev itself uses the normal |
2250 | Modern systems have a variety of clocks \- libev itself uses the normal |
… | |
… | |
2228 | .IX Item "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" |
2315 | .IX Item "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" |
2229 | .PD 0 |
2316 | .PD 0 |
2230 | .IP "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)" 4 |
2317 | .IP "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)" 4 |
2231 | .IX Item "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)" |
2318 | .IX Item "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)" |
2232 | .PD |
2319 | .PD |
2233 | Configure the timer to trigger after \f(CW\*(C`after\*(C'\fR seconds. If \f(CW\*(C`repeat\*(C'\fR |
2320 | Configure the timer to trigger after \f(CW\*(C`after\*(C'\fR seconds (fractional and |
2234 | is \f(CW0.\fR, then it will automatically be stopped once the timeout is |
2321 | negative values are supported). If \f(CW\*(C`repeat\*(C'\fR is \f(CW0.\fR, then it will |
2235 | reached. If it is positive, then the timer will automatically be |
2322 | automatically be stopped once the timeout is reached. If it is positive, |
2236 | configured to trigger again \f(CW\*(C`repeat\*(C'\fR seconds later, again, and again, |
2323 | then the timer will automatically be configured to trigger again \f(CW\*(C`repeat\*(C'\fR |
2237 | until stopped manually. |
2324 | seconds later, again, and again, until stopped manually. |
2238 | .Sp |
2325 | .Sp |
2239 | The timer itself will do a best-effort at avoiding drift, that is, if |
2326 | The timer itself will do a best-effort at avoiding drift, that is, if |
2240 | you configure a timer to trigger every 10 seconds, then it will normally |
2327 | you configure a timer to trigger every 10 seconds, then it will normally |
2241 | trigger at exactly 10 second intervals. If, however, your program cannot |
2328 | trigger at exactly 10 second intervals. If, however, your program cannot |
2242 | keep up with the timer (because it takes longer than those 10 seconds to |
2329 | keep up with the timer (because it takes longer than those 10 seconds to |
… | |
… | |
2324 | Periodic watchers are also timers of a kind, but they are very versatile |
2411 | Periodic watchers are also timers of a kind, but they are very versatile |
2325 | (and unfortunately a bit complex). |
2412 | (and unfortunately a bit complex). |
2326 | .PP |
2413 | .PP |
2327 | Unlike \f(CW\*(C`ev_timer\*(C'\fR, periodic watchers are not based on real time (or |
2414 | Unlike \f(CW\*(C`ev_timer\*(C'\fR, periodic watchers are not based on real time (or |
2328 | relative time, the physical time that passes) but on wall clock time |
2415 | relative time, the physical time that passes) but on wall clock time |
2329 | (absolute time, the thing you can read on your calender or clock). The |
2416 | (absolute time, the thing you can read on your calendar or clock). The |
2330 | difference is that wall clock time can run faster or slower than real |
2417 | difference is that wall clock time can run faster or slower than real |
2331 | time, and time jumps are not uncommon (e.g. when you adjust your |
2418 | time, and time jumps are not uncommon (e.g. when you adjust your |
2332 | wrist-watch). |
2419 | wrist-watch). |
2333 | .PP |
2420 | .PP |
2334 | You can tell a periodic watcher to trigger after some specific point |
2421 | You can tell a periodic watcher to trigger after some specific point |
… | |
… | |
2339 | \&\f(CW\*(C`ev_timer\*(C'\fR, which would still trigger roughly 10 seconds after starting |
2426 | \&\f(CW\*(C`ev_timer\*(C'\fR, which would still trigger roughly 10 seconds after starting |
2340 | it, as it uses a relative timeout). |
2427 | it, as it uses a relative timeout). |
2341 | .PP |
2428 | .PP |
2342 | \&\f(CW\*(C`ev_periodic\*(C'\fR watchers can also be used to implement vastly more complex |
2429 | \&\f(CW\*(C`ev_periodic\*(C'\fR watchers can also be used to implement vastly more complex |
2343 | timers, such as triggering an event on each \*(L"midnight, local time\*(R", or |
2430 | timers, such as triggering an event on each \*(L"midnight, local time\*(R", or |
2344 | other complicated rules. This cannot be done with \f(CW\*(C`ev_timer\*(C'\fR watchers, as |
2431 | other complicated rules. This cannot easily be done with \f(CW\*(C`ev_timer\*(C'\fR |
2345 | those cannot react to time jumps. |
2432 | watchers, as those cannot react to time jumps. |
2346 | .PP |
2433 | .PP |
2347 | As with timers, the callback is guaranteed to be invoked only when the |
2434 | As with timers, the callback is guaranteed to be invoked only when the |
2348 | point in time where it is supposed to trigger has passed. If multiple |
2435 | point in time where it is supposed to trigger has passed. If multiple |
2349 | timers become ready during the same loop iteration then the ones with |
2436 | timers become ready during the same loop iteration then the ones with |
2350 | earlier time-out values are invoked before ones with later time-out values |
2437 | earlier time-out values are invoked before ones with later time-out values |
… | |
… | |
2411 | In this mode the values for \f(CW\*(C`interval\*(C'\fR and \f(CW\*(C`offset\*(C'\fR are both being |
2498 | In this mode the values for \f(CW\*(C`interval\*(C'\fR and \f(CW\*(C`offset\*(C'\fR are both being |
2412 | ignored. Instead, each time the periodic watcher gets scheduled, the |
2499 | ignored. Instead, each time the periodic watcher gets scheduled, the |
2413 | reschedule callback will be called with the watcher as first, and the |
2500 | reschedule callback will be called with the watcher as first, and the |
2414 | current time as second argument. |
2501 | current time as second argument. |
2415 | .Sp |
2502 | .Sp |
2416 | \&\s-1NOTE:\s0 \fIThis callback \s-1MUST\s0 \s-1NOT\s0 stop or destroy any periodic watcher, ever, |
2503 | \&\s-1NOTE:\s0 \fIThis callback \s-1MUST NOT\s0 stop or destroy any periodic watcher, ever, |
2417 | or make \s-1ANY\s0 other event loop modifications whatsoever, unless explicitly |
2504 | or make \s-1ANY\s0 other event loop modifications whatsoever, unless explicitly |
2418 | allowed by documentation here\fR. |
2505 | allowed by documentation here\fR. |
2419 | .Sp |
2506 | .Sp |
2420 | If you need to stop it, return \f(CW\*(C`now + 1e30\*(C'\fR (or so, fudge fudge) and stop |
2507 | If you need to stop it, return \f(CW\*(C`now + 1e30\*(C'\fR (or so, fudge fudge) and stop |
2421 | it afterwards (e.g. by starting an \f(CW\*(C`ev_prepare\*(C'\fR watcher, which is the |
2508 | it afterwards (e.g. by starting an \f(CW\*(C`ev_prepare\*(C'\fR watcher, which is the |
… | |
… | |
2439 | .Sp |
2526 | .Sp |
2440 | \&\s-1NOTE:\s0 \fIThis callback must always return a time that is higher than or |
2527 | \&\s-1NOTE:\s0 \fIThis callback must always return a time that is higher than or |
2441 | equal to the passed \f(CI\*(C`now\*(C'\fI value\fR. |
2528 | equal to the passed \f(CI\*(C`now\*(C'\fI value\fR. |
2442 | .Sp |
2529 | .Sp |
2443 | This can be used to create very complex timers, such as a timer that |
2530 | This can be used to create very complex timers, such as a timer that |
2444 | triggers on \*(L"next midnight, local time\*(R". To do this, you would calculate the |
2531 | triggers on \*(L"next midnight, local time\*(R". To do this, you would calculate |
2445 | next midnight after \f(CW\*(C`now\*(C'\fR and return the timestamp value for this. How |
2532 | the next midnight after \f(CW\*(C`now\*(C'\fR and return the timestamp value for |
2446 | you do this is, again, up to you (but it is not trivial, which is the main |
2533 | this. Here is a (completely untested, no error checking) example on how to |
2447 | reason I omitted it as an example). |
2534 | do this: |
|
|
2535 | .Sp |
|
|
2536 | .Vb 1 |
|
|
2537 | \& #include <time.h> |
|
|
2538 | \& |
|
|
2539 | \& static ev_tstamp |
|
|
2540 | \& my_rescheduler (ev_periodic *w, ev_tstamp now) |
|
|
2541 | \& { |
|
|
2542 | \& time_t tnow = (time_t)now; |
|
|
2543 | \& struct tm tm; |
|
|
2544 | \& localtime_r (&tnow, &tm); |
|
|
2545 | \& |
|
|
2546 | \& tm.tm_sec = tm.tm_min = tm.tm_hour = 0; // midnight current day |
|
|
2547 | \& ++tm.tm_mday; // midnight next day |
|
|
2548 | \& |
|
|
2549 | \& return mktime (&tm); |
|
|
2550 | \& } |
|
|
2551 | .Ve |
|
|
2552 | .Sp |
|
|
2553 | Note: this code might run into trouble on days that have more then two |
|
|
2554 | midnights (beginning and end). |
2448 | .RE |
2555 | .RE |
2449 | .RS 4 |
2556 | .RS 4 |
2450 | .RE |
2557 | .RE |
2451 | .IP "ev_periodic_again (loop, ev_periodic *)" 4 |
2558 | .IP "ev_periodic_again (loop, ev_periodic *)" 4 |
2452 | .IX Item "ev_periodic_again (loop, ev_periodic *)" |
2559 | .IX Item "ev_periodic_again (loop, ev_periodic *)" |
… | |
… | |
2537 | only within the same loop, i.e. you can watch for \f(CW\*(C`SIGINT\*(C'\fR in your |
2644 | only within the same loop, i.e. you can watch for \f(CW\*(C`SIGINT\*(C'\fR in your |
2538 | default loop and for \f(CW\*(C`SIGIO\*(C'\fR in another loop, but you cannot watch for |
2645 | default loop and for \f(CW\*(C`SIGIO\*(C'\fR in another loop, but you cannot watch for |
2539 | \&\f(CW\*(C`SIGINT\*(C'\fR in both the default loop and another loop at the same time. At |
2646 | \&\f(CW\*(C`SIGINT\*(C'\fR in both the default loop and another loop at the same time. At |
2540 | the moment, \f(CW\*(C`SIGCHLD\*(C'\fR is permanently tied to the default loop. |
2647 | the moment, \f(CW\*(C`SIGCHLD\*(C'\fR is permanently tied to the default loop. |
2541 | .PP |
2648 | .PP |
2542 | When the first watcher gets started will libev actually register something |
2649 | Only after the first watcher for a signal is started will libev actually |
2543 | with the kernel (thus it coexists with your own signal handlers as long as |
2650 | register something with the kernel. It thus coexists with your own signal |
2544 | you don't register any with libev for the same signal). |
2651 | handlers as long as you don't register any with libev for the same signal. |
2545 | .PP |
2652 | .PP |
2546 | If possible and supported, libev will install its handlers with |
2653 | If possible and supported, libev will install its handlers with |
2547 | \&\f(CW\*(C`SA_RESTART\*(C'\fR (or equivalent) behaviour enabled, so system calls should |
2654 | \&\f(CW\*(C`SA_RESTART\*(C'\fR (or equivalent) behaviour enabled, so system calls should |
2548 | not be unduly interrupted. If you have a problem with system calls getting |
2655 | not be unduly interrupted. If you have a problem with system calls getting |
2549 | interrupted by signals you can block all signals in an \f(CW\*(C`ev_check\*(C'\fR watcher |
2656 | interrupted by signals you can block all signals in an \f(CW\*(C`ev_check\*(C'\fR watcher |
… | |
… | |
2610 | The signal the watcher watches out for. |
2717 | The signal the watcher watches out for. |
2611 | .PP |
2718 | .PP |
2612 | \fIExamples\fR |
2719 | \fIExamples\fR |
2613 | .IX Subsection "Examples" |
2720 | .IX Subsection "Examples" |
2614 | .PP |
2721 | .PP |
2615 | Example: Try to exit cleanly on \s-1SIGINT\s0. |
2722 | Example: Try to exit cleanly on \s-1SIGINT.\s0 |
2616 | .PP |
2723 | .PP |
2617 | .Vb 5 |
2724 | .Vb 5 |
2618 | \& static void |
2725 | \& static void |
2619 | \& sigint_cb (struct ev_loop *loop, ev_signal *w, int revents) |
2726 | \& sigint_cb (struct ev_loop *loop, ev_signal *w, int revents) |
2620 | \& { |
2727 | \& { |
… | |
… | |
2735 | .ie n .SS """ev_stat"" \- did the file attributes just change?" |
2842 | .ie n .SS """ev_stat"" \- did the file attributes just change?" |
2736 | .el .SS "\f(CWev_stat\fP \- did the file attributes just change?" |
2843 | .el .SS "\f(CWev_stat\fP \- did the file attributes just change?" |
2737 | .IX Subsection "ev_stat - did the file attributes just change?" |
2844 | .IX Subsection "ev_stat - did the file attributes just change?" |
2738 | This watches a file system path for attribute changes. That is, it calls |
2845 | This watches a file system path for attribute changes. That is, it calls |
2739 | \&\f(CW\*(C`stat\*(C'\fR on that path in regular intervals (or when the \s-1OS\s0 says it changed) |
2846 | \&\f(CW\*(C`stat\*(C'\fR on that path in regular intervals (or when the \s-1OS\s0 says it changed) |
2740 | and sees if it changed compared to the last time, invoking the callback if |
2847 | and sees if it changed compared to the last time, invoking the callback |
2741 | it did. |
2848 | if it did. Starting the watcher \f(CW\*(C`stat\*(C'\fR's the file, so only changes that |
|
|
2849 | happen after the watcher has been started will be reported. |
2742 | .PP |
2850 | .PP |
2743 | The path does not need to exist: changing from \*(L"path exists\*(R" to \*(L"path does |
2851 | The path does not need to exist: changing from \*(L"path exists\*(R" to \*(L"path does |
2744 | not exist\*(R" is a status change like any other. The condition \*(L"path does not |
2852 | not exist\*(R" is a status change like any other. The condition \*(L"path does not |
2745 | exist\*(R" (or more correctly \*(L"path cannot be stat'ed\*(R") is signified by the |
2853 | exist\*(R" (or more correctly \*(L"path cannot be stat'ed\*(R") is signified by the |
2746 | \&\f(CW\*(C`st_nlink\*(C'\fR field being zero (which is otherwise always forced to be at |
2854 | \&\f(CW\*(C`st_nlink\*(C'\fR field being zero (which is otherwise always forced to be at |
… | |
… | |
2776 | compilation environment, which means that on systems with large file |
2884 | compilation environment, which means that on systems with large file |
2777 | support disabled by default, you get the 32 bit version of the stat |
2885 | support disabled by default, you get the 32 bit version of the stat |
2778 | structure. When using the library from programs that change the \s-1ABI\s0 to |
2886 | structure. When using the library from programs that change the \s-1ABI\s0 to |
2779 | use 64 bit file offsets the programs will fail. In that case you have to |
2887 | use 64 bit file offsets the programs will fail. In that case you have to |
2780 | compile libev with the same flags to get binary compatibility. This is |
2888 | compile libev with the same flags to get binary compatibility. This is |
2781 | obviously the case with any flags that change the \s-1ABI\s0, but the problem is |
2889 | obviously the case with any flags that change the \s-1ABI,\s0 but the problem is |
2782 | most noticeably displayed with ev_stat and large file support. |
2890 | most noticeably displayed with ev_stat and large file support. |
2783 | .PP |
2891 | .PP |
2784 | The solution for this is to lobby your distribution maker to make large |
2892 | The solution for this is to lobby your distribution maker to make large |
2785 | file interfaces available by default (as e.g. FreeBSD does) and not |
2893 | file interfaces available by default (as e.g. FreeBSD does) and not |
2786 | optional. Libev cannot simply switch on large file support because it has |
2894 | optional. Libev cannot simply switch on large file support because it has |
… | |
… | |
2977 | Apart from keeping your process non-blocking (which is a useful |
3085 | Apart from keeping your process non-blocking (which is a useful |
2978 | effect on its own sometimes), idle watchers are a good place to do |
3086 | effect on its own sometimes), idle watchers are a good place to do |
2979 | \&\*(L"pseudo-background processing\*(R", or delay processing stuff to after the |
3087 | \&\*(L"pseudo-background processing\*(R", or delay processing stuff to after the |
2980 | event loop has handled all outstanding events. |
3088 | event loop has handled all outstanding events. |
2981 | .PP |
3089 | .PP |
|
|
3090 | \fIAbusing an \f(CI\*(C`ev_idle\*(C'\fI watcher for its side-effect\fR |
|
|
3091 | .IX Subsection "Abusing an ev_idle watcher for its side-effect" |
|
|
3092 | .PP |
|
|
3093 | As long as there is at least one active idle watcher, libev will never |
|
|
3094 | sleep unnecessarily. Or in other words, it will loop as fast as possible. |
|
|
3095 | For this to work, the idle watcher doesn't need to be invoked at all \- the |
|
|
3096 | lowest priority will do. |
|
|
3097 | .PP |
|
|
3098 | This mode of operation can be useful together with an \f(CW\*(C`ev_check\*(C'\fR watcher, |
|
|
3099 | to do something on each event loop iteration \- for example to balance load |
|
|
3100 | between different connections. |
|
|
3101 | .PP |
|
|
3102 | See \*(L"Abusing an ev_check watcher for its side-effect\*(R" for a longer |
|
|
3103 | example. |
|
|
3104 | .PP |
2982 | \fIWatcher-Specific Functions and Data Members\fR |
3105 | \fIWatcher-Specific Functions and Data Members\fR |
2983 | .IX Subsection "Watcher-Specific Functions and Data Members" |
3106 | .IX Subsection "Watcher-Specific Functions and Data Members" |
2984 | .IP "ev_idle_init (ev_idle *, callback)" 4 |
3107 | .IP "ev_idle_init (ev_idle *, callback)" 4 |
2985 | .IX Item "ev_idle_init (ev_idle *, callback)" |
3108 | .IX Item "ev_idle_init (ev_idle *, callback)" |
2986 | Initialises and configures the idle watcher \- it has no parameters of any |
3109 | Initialises and configures the idle watcher \- it has no parameters of any |
… | |
… | |
2991 | .IX Subsection "Examples" |
3114 | .IX Subsection "Examples" |
2992 | .PP |
3115 | .PP |
2993 | Example: Dynamically allocate an \f(CW\*(C`ev_idle\*(C'\fR watcher, start it, and in the |
3116 | Example: Dynamically allocate an \f(CW\*(C`ev_idle\*(C'\fR watcher, start it, and in the |
2994 | callback, free it. Also, use no error checking, as usual. |
3117 | callback, free it. Also, use no error checking, as usual. |
2995 | .PP |
3118 | .PP |
2996 | .Vb 7 |
3119 | .Vb 5 |
2997 | \& static void |
3120 | \& static void |
2998 | \& idle_cb (struct ev_loop *loop, ev_idle *w, int revents) |
3121 | \& idle_cb (struct ev_loop *loop, ev_idle *w, int revents) |
2999 | \& { |
3122 | \& { |
|
|
3123 | \& // stop the watcher |
|
|
3124 | \& ev_idle_stop (loop, w); |
|
|
3125 | \& |
|
|
3126 | \& // now we can free it |
3000 | \& free (w); |
3127 | \& free (w); |
|
|
3128 | \& |
3001 | \& // now do something you wanted to do when the program has |
3129 | \& // now do something you wanted to do when the program has |
3002 | \& // no longer anything immediate to do. |
3130 | \& // no longer anything immediate to do. |
3003 | \& } |
3131 | \& } |
3004 | \& |
3132 | \& |
3005 | \& ev_idle *idle_watcher = malloc (sizeof (ev_idle)); |
3133 | \& ev_idle *idle_watcher = malloc (sizeof (ev_idle)); |
… | |
… | |
3007 | \& ev_idle_start (loop, idle_watcher); |
3135 | \& ev_idle_start (loop, idle_watcher); |
3008 | .Ve |
3136 | .Ve |
3009 | .ie n .SS """ev_prepare"" and ""ev_check"" \- customise your event loop!" |
3137 | .ie n .SS """ev_prepare"" and ""ev_check"" \- customise your event loop!" |
3010 | .el .SS "\f(CWev_prepare\fP and \f(CWev_check\fP \- customise your event loop!" |
3138 | .el .SS "\f(CWev_prepare\fP and \f(CWev_check\fP \- customise your event loop!" |
3011 | .IX Subsection "ev_prepare and ev_check - customise your event loop!" |
3139 | .IX Subsection "ev_prepare and ev_check - customise your event loop!" |
3012 | Prepare and check watchers are usually (but not always) used in pairs: |
3140 | Prepare and check watchers are often (but not always) used in pairs: |
3013 | prepare watchers get invoked before the process blocks and check watchers |
3141 | prepare watchers get invoked before the process blocks and check watchers |
3014 | afterwards. |
3142 | afterwards. |
3015 | .PP |
3143 | .PP |
3016 | You \fImust not\fR call \f(CW\*(C`ev_run\*(C'\fR or similar functions that enter |
3144 | You \fImust not\fR call \f(CW\*(C`ev_run\*(C'\fR (or similar functions that enter the |
3017 | the current event loop from either \f(CW\*(C`ev_prepare\*(C'\fR or \f(CW\*(C`ev_check\*(C'\fR |
3145 | current event loop) or \f(CW\*(C`ev_loop_fork\*(C'\fR from either \f(CW\*(C`ev_prepare\*(C'\fR or |
3018 | watchers. Other loops than the current one are fine, however. The |
3146 | \&\f(CW\*(C`ev_check\*(C'\fR watchers. Other loops than the current one are fine, |
3019 | rationale behind this is that you do not need to check for recursion in |
3147 | however. The rationale behind this is that you do not need to check |
3020 | those watchers, i.e. the sequence will always be \f(CW\*(C`ev_prepare\*(C'\fR, blocking, |
3148 | for recursion in those watchers, i.e. the sequence will always be |
3021 | \&\f(CW\*(C`ev_check\*(C'\fR so if you have one watcher of each kind they will always be |
3149 | \&\f(CW\*(C`ev_prepare\*(C'\fR, blocking, \f(CW\*(C`ev_check\*(C'\fR so if you have one watcher of each |
3022 | called in pairs bracketing the blocking call. |
3150 | kind they will always be called in pairs bracketing the blocking call. |
3023 | .PP |
3151 | .PP |
3024 | Their main purpose is to integrate other event mechanisms into libev and |
3152 | Their main purpose is to integrate other event mechanisms into libev and |
3025 | their use is somewhat advanced. They could be used, for example, to track |
3153 | their use is somewhat advanced. They could be used, for example, to track |
3026 | variable changes, implement your own watchers, integrate net-snmp or a |
3154 | variable changes, implement your own watchers, integrate net-snmp or a |
3027 | coroutine library and lots more. They are also occasionally useful if |
3155 | coroutine library and lots more. They are also occasionally useful if |
… | |
… | |
3045 | with priority higher than or equal to the event loop and one coroutine |
3173 | with priority higher than or equal to the event loop and one coroutine |
3046 | of lower priority, but only once, using idle watchers to keep the event |
3174 | of lower priority, but only once, using idle watchers to keep the event |
3047 | loop from blocking if lower-priority coroutines are active, thus mapping |
3175 | loop from blocking if lower-priority coroutines are active, thus mapping |
3048 | low-priority coroutines to idle/background tasks). |
3176 | low-priority coroutines to idle/background tasks). |
3049 | .PP |
3177 | .PP |
3050 | It is recommended to give \f(CW\*(C`ev_check\*(C'\fR watchers highest (\f(CW\*(C`EV_MAXPRI\*(C'\fR) |
3178 | When used for this purpose, it is recommended to give \f(CW\*(C`ev_check\*(C'\fR watchers |
3051 | priority, to ensure that they are being run before any other watchers |
3179 | highest (\f(CW\*(C`EV_MAXPRI\*(C'\fR) priority, to ensure that they are being run before |
3052 | after the poll (this doesn't matter for \f(CW\*(C`ev_prepare\*(C'\fR watchers). |
3180 | any other watchers after the poll (this doesn't matter for \f(CW\*(C`ev_prepare\*(C'\fR |
|
|
3181 | watchers). |
3053 | .PP |
3182 | .PP |
3054 | Also, \f(CW\*(C`ev_check\*(C'\fR watchers (and \f(CW\*(C`ev_prepare\*(C'\fR watchers, too) should not |
3183 | Also, \f(CW\*(C`ev_check\*(C'\fR watchers (and \f(CW\*(C`ev_prepare\*(C'\fR watchers, too) should not |
3055 | activate (\*(L"feed\*(R") events into libev. While libev fully supports this, they |
3184 | activate (\*(L"feed\*(R") events into libev. While libev fully supports this, they |
3056 | might get executed before other \f(CW\*(C`ev_check\*(C'\fR watchers did their job. As |
3185 | might get executed before other \f(CW\*(C`ev_check\*(C'\fR watchers did their job. As |
3057 | \&\f(CW\*(C`ev_check\*(C'\fR watchers are often used to embed other (non-libev) event |
3186 | \&\f(CW\*(C`ev_check\*(C'\fR watchers are often used to embed other (non-libev) event |
3058 | loops those other event loops might be in an unusable state until their |
3187 | loops those other event loops might be in an unusable state until their |
3059 | \&\f(CW\*(C`ev_check\*(C'\fR watcher ran (always remind yourself to coexist peacefully with |
3188 | \&\f(CW\*(C`ev_check\*(C'\fR watcher ran (always remind yourself to coexist peacefully with |
3060 | others). |
3189 | others). |
|
|
3190 | .PP |
|
|
3191 | \fIAbusing an \f(CI\*(C`ev_check\*(C'\fI watcher for its side-effect\fR |
|
|
3192 | .IX Subsection "Abusing an ev_check watcher for its side-effect" |
|
|
3193 | .PP |
|
|
3194 | \&\f(CW\*(C`ev_check\*(C'\fR (and less often also \f(CW\*(C`ev_prepare\*(C'\fR) watchers can also be |
|
|
3195 | useful because they are called once per event loop iteration. For |
|
|
3196 | example, if you want to handle a large number of connections fairly, you |
|
|
3197 | normally only do a bit of work for each active connection, and if there |
|
|
3198 | is more work to do, you wait for the next event loop iteration, so other |
|
|
3199 | connections have a chance of making progress. |
|
|
3200 | .PP |
|
|
3201 | Using an \f(CW\*(C`ev_check\*(C'\fR watcher is almost enough: it will be called on the |
|
|
3202 | next event loop iteration. However, that isn't as soon as possible \- |
|
|
3203 | without external events, your \f(CW\*(C`ev_check\*(C'\fR watcher will not be invoked. |
|
|
3204 | .PP |
|
|
3205 | This is where \f(CW\*(C`ev_idle\*(C'\fR watchers come in handy \- all you need is a |
|
|
3206 | single global idle watcher that is active as long as you have one active |
|
|
3207 | \&\f(CW\*(C`ev_check\*(C'\fR watcher. The \f(CW\*(C`ev_idle\*(C'\fR watcher makes sure the event loop |
|
|
3208 | will not sleep, and the \f(CW\*(C`ev_check\*(C'\fR watcher makes sure a callback gets |
|
|
3209 | invoked. Neither watcher alone can do that. |
3061 | .PP |
3210 | .PP |
3062 | \fIWatcher-Specific Functions and Data Members\fR |
3211 | \fIWatcher-Specific Functions and Data Members\fR |
3063 | .IX Subsection "Watcher-Specific Functions and Data Members" |
3212 | .IX Subsection "Watcher-Specific Functions and Data Members" |
3064 | .IP "ev_prepare_init (ev_prepare *, callback)" 4 |
3213 | .IP "ev_prepare_init (ev_prepare *, callback)" 4 |
3065 | .IX Item "ev_prepare_init (ev_prepare *, callback)" |
3214 | .IX Item "ev_prepare_init (ev_prepare *, callback)" |
… | |
… | |
3176 | .Ve |
3325 | .Ve |
3177 | .PP |
3326 | .PP |
3178 | Method 4: Do not use a prepare or check watcher because the module you |
3327 | Method 4: Do not use a prepare or check watcher because the module you |
3179 | want to embed is not flexible enough to support it. Instead, you can |
3328 | want to embed is not flexible enough to support it. Instead, you can |
3180 | override their poll function. The drawback with this solution is that the |
3329 | override their poll function. The drawback with this solution is that the |
3181 | main loop is now no longer controllable by \s-1EV\s0. The \f(CW\*(C`Glib::EV\*(C'\fR module uses |
3330 | main loop is now no longer controllable by \s-1EV.\s0 The \f(CW\*(C`Glib::EV\*(C'\fR module uses |
3182 | this approach, effectively embedding \s-1EV\s0 as a client into the horrible |
3331 | this approach, effectively embedding \s-1EV\s0 as a client into the horrible |
3183 | libglib event loop. |
3332 | libglib event loop. |
3184 | .PP |
3333 | .PP |
3185 | .Vb 4 |
3334 | .Vb 4 |
3186 | \& static gint |
3335 | \& static gint |
… | |
… | |
3270 | \fIWatcher-Specific Functions and Data Members\fR |
3419 | \fIWatcher-Specific Functions and Data Members\fR |
3271 | .IX Subsection "Watcher-Specific Functions and Data Members" |
3420 | .IX Subsection "Watcher-Specific Functions and Data Members" |
3272 | .IP "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
3421 | .IP "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
3273 | .IX Item "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" |
3422 | .IX Item "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" |
3274 | .PD 0 |
3423 | .PD 0 |
3275 | .IP "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
3424 | .IP "ev_embed_set (ev_embed *, struct ev_loop *embedded_loop)" 4 |
3276 | .IX Item "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" |
3425 | .IX Item "ev_embed_set (ev_embed *, struct ev_loop *embedded_loop)" |
3277 | .PD |
3426 | .PD |
3278 | Configures the watcher to embed the given loop, which must be |
3427 | Configures the watcher to embed the given loop, which must be |
3279 | embeddable. If the callback is \f(CW0\fR, then \f(CW\*(C`ev_embed_sweep\*(C'\fR will be |
3428 | embeddable. If the callback is \f(CW0\fR, then \f(CW\*(C`ev_embed_sweep\*(C'\fR will be |
3280 | invoked automatically, otherwise it is the responsibility of the callback |
3429 | invoked automatically, otherwise it is the responsibility of the callback |
3281 | to invoke it (it will continue to be called until the sweep has been done, |
3430 | to invoke it (it will continue to be called until the sweep has been done, |
… | |
… | |
3300 | .PP |
3449 | .PP |
3301 | .Vb 3 |
3450 | .Vb 3 |
3302 | \& struct ev_loop *loop_hi = ev_default_init (0); |
3451 | \& struct ev_loop *loop_hi = ev_default_init (0); |
3303 | \& struct ev_loop *loop_lo = 0; |
3452 | \& struct ev_loop *loop_lo = 0; |
3304 | \& ev_embed embed; |
3453 | \& ev_embed embed; |
3305 | \& |
3454 | \& |
3306 | \& // see if there is a chance of getting one that works |
3455 | \& // see if there is a chance of getting one that works |
3307 | \& // (remember that a flags value of 0 means autodetection) |
3456 | \& // (remember that a flags value of 0 means autodetection) |
3308 | \& loop_lo = ev_embeddable_backends () & ev_recommended_backends () |
3457 | \& loop_lo = ev_embeddable_backends () & ev_recommended_backends () |
3309 | \& ? ev_loop_new (ev_embeddable_backends () & ev_recommended_backends ()) |
3458 | \& ? ev_loop_new (ev_embeddable_backends () & ev_recommended_backends ()) |
3310 | \& : 0; |
3459 | \& : 0; |
… | |
… | |
3326 | .PP |
3475 | .PP |
3327 | .Vb 3 |
3476 | .Vb 3 |
3328 | \& struct ev_loop *loop = ev_default_init (0); |
3477 | \& struct ev_loop *loop = ev_default_init (0); |
3329 | \& struct ev_loop *loop_socket = 0; |
3478 | \& struct ev_loop *loop_socket = 0; |
3330 | \& ev_embed embed; |
3479 | \& ev_embed embed; |
3331 | \& |
3480 | \& |
3332 | \& if (ev_supported_backends () & ~ev_recommended_backends () & EVBACKEND_KQUEUE) |
3481 | \& if (ev_supported_backends () & ~ev_recommended_backends () & EVBACKEND_KQUEUE) |
3333 | \& if ((loop_socket = ev_loop_new (EVBACKEND_KQUEUE)) |
3482 | \& if ((loop_socket = ev_loop_new (EVBACKEND_KQUEUE)) |
3334 | \& { |
3483 | \& { |
3335 | \& ev_embed_init (&embed, 0, loop_socket); |
3484 | \& ev_embed_init (&embed, 0, loop_socket); |
3336 | \& ev_embed_start (loop, &embed); |
3485 | \& ev_embed_start (loop, &embed); |
… | |
… | |
3344 | .ie n .SS """ev_fork"" \- the audacity to resume the event loop after a fork" |
3493 | .ie n .SS """ev_fork"" \- the audacity to resume the event loop after a fork" |
3345 | .el .SS "\f(CWev_fork\fP \- the audacity to resume the event loop after a fork" |
3494 | .el .SS "\f(CWev_fork\fP \- the audacity to resume the event loop after a fork" |
3346 | .IX Subsection "ev_fork - the audacity to resume the event loop after a fork" |
3495 | .IX Subsection "ev_fork - the audacity to resume the event loop after a fork" |
3347 | Fork watchers are called when a \f(CW\*(C`fork ()\*(C'\fR was detected (usually because |
3496 | Fork watchers are called when a \f(CW\*(C`fork ()\*(C'\fR was detected (usually because |
3348 | whoever is a good citizen cared to tell libev about it by calling |
3497 | whoever is a good citizen cared to tell libev about it by calling |
3349 | \&\f(CW\*(C`ev_default_fork\*(C'\fR or \f(CW\*(C`ev_loop_fork\*(C'\fR). The invocation is done before the |
3498 | \&\f(CW\*(C`ev_loop_fork\*(C'\fR). The invocation is done before the event loop blocks next |
3350 | event loop blocks next and before \f(CW\*(C`ev_check\*(C'\fR watchers are being called, |
3499 | and before \f(CW\*(C`ev_check\*(C'\fR watchers are being called, and only in the child |
3351 | and only in the child after the fork. If whoever good citizen calling |
3500 | after the fork. If whoever good citizen calling \f(CW\*(C`ev_default_fork\*(C'\fR cheats |
3352 | \&\f(CW\*(C`ev_default_fork\*(C'\fR cheats and calls it in the wrong process, the fork |
3501 | and calls it in the wrong process, the fork handlers will be invoked, too, |
3353 | handlers will be invoked, too, of course. |
3502 | of course. |
3354 | .PP |
3503 | .PP |
3355 | \fIThe special problem of life after fork \- how is it possible?\fR |
3504 | \fIThe special problem of life after fork \- how is it possible?\fR |
3356 | .IX Subsection "The special problem of life after fork - how is it possible?" |
3505 | .IX Subsection "The special problem of life after fork - how is it possible?" |
3357 | .PP |
3506 | .PP |
3358 | Most uses of \f(CW\*(C`fork()\*(C'\fR consist of forking, then some simple calls to set |
3507 | Most uses of \f(CW\*(C`fork ()\*(C'\fR consist of forking, then some simple calls to set |
3359 | up/change the process environment, followed by a call to \f(CW\*(C`exec()\*(C'\fR. This |
3508 | up/change the process environment, followed by a call to \f(CW\*(C`exec()\*(C'\fR. This |
3360 | sequence should be handled by libev without any problems. |
3509 | sequence should be handled by libev without any problems. |
3361 | .PP |
3510 | .PP |
3362 | This changes when the application actually wants to do event handling |
3511 | This changes when the application actually wants to do event handling |
3363 | in the child, or both parent in child, in effect \*(L"continuing\*(R" after the |
3512 | in the child, or both parent in child, in effect \*(L"continuing\*(R" after the |
… | |
… | |
3444 | it by calling \f(CW\*(C`ev_async_send\*(C'\fR, which is thread\- and signal safe. |
3593 | it by calling \f(CW\*(C`ev_async_send\*(C'\fR, which is thread\- and signal safe. |
3445 | .PP |
3594 | .PP |
3446 | This functionality is very similar to \f(CW\*(C`ev_signal\*(C'\fR watchers, as signals, |
3595 | This functionality is very similar to \f(CW\*(C`ev_signal\*(C'\fR watchers, as signals, |
3447 | too, are asynchronous in nature, and signals, too, will be compressed |
3596 | too, are asynchronous in nature, and signals, too, will be compressed |
3448 | (i.e. the number of callback invocations may be less than the number of |
3597 | (i.e. the number of callback invocations may be less than the number of |
3449 | \&\f(CW\*(C`ev_async_sent\*(C'\fR calls). In fact, you could use signal watchers as a kind |
3598 | \&\f(CW\*(C`ev_async_send\*(C'\fR calls). In fact, you could use signal watchers as a kind |
3450 | of \*(L"global async watchers\*(R" by using a watcher on an otherwise unused |
3599 | of \*(L"global async watchers\*(R" by using a watcher on an otherwise unused |
3451 | signal, and \f(CW\*(C`ev_feed_signal\*(C'\fR to signal this watcher from another thread, |
3600 | signal, and \f(CW\*(C`ev_feed_signal\*(C'\fR to signal this watcher from another thread, |
3452 | even without knowing which loop owns the signal. |
3601 | even without knowing which loop owns the signal. |
3453 | .PP |
3602 | .PP |
3454 | \fIQueueing\fR |
3603 | \fIQueueing\fR |
… | |
… | |
3580 | is a time window between the event loop checking and resetting the async |
3729 | is a time window between the event loop checking and resetting the async |
3581 | notification, and the callback being invoked. |
3730 | notification, and the callback being invoked. |
3582 | .SH "OTHER FUNCTIONS" |
3731 | .SH "OTHER FUNCTIONS" |
3583 | .IX Header "OTHER FUNCTIONS" |
3732 | .IX Header "OTHER FUNCTIONS" |
3584 | There are some other functions of possible interest. Described. Here. Now. |
3733 | There are some other functions of possible interest. Described. Here. Now. |
3585 | .IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4 |
3734 | .IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback, arg)" 4 |
3586 | .IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" |
3735 | .IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback, arg)" |
3587 | This function combines a simple timer and an I/O watcher, calls your |
3736 | This function combines a simple timer and an I/O watcher, calls your |
3588 | callback on whichever event happens first and automatically stops both |
3737 | callback on whichever event happens first and automatically stops both |
3589 | watchers. This is useful if you want to wait for a single event on an fd |
3738 | watchers. This is useful if you want to wait for a single event on an fd |
3590 | or timeout without having to allocate/configure/start/stop/free one or |
3739 | or timeout without having to allocate/configure/start/stop/free one or |
3591 | more watchers yourself. |
3740 | more watchers yourself. |
… | |
… | |
3603 | \&\f(CW\*(C`EV_ERROR\*(C'\fR, \f(CW\*(C`EV_READ\*(C'\fR, \f(CW\*(C`EV_WRITE\*(C'\fR or \f(CW\*(C`EV_TIMER\*(C'\fR) and the \f(CW\*(C`arg\*(C'\fR |
3752 | \&\f(CW\*(C`EV_ERROR\*(C'\fR, \f(CW\*(C`EV_READ\*(C'\fR, \f(CW\*(C`EV_WRITE\*(C'\fR or \f(CW\*(C`EV_TIMER\*(C'\fR) and the \f(CW\*(C`arg\*(C'\fR |
3604 | value passed to \f(CW\*(C`ev_once\*(C'\fR. Note that it is possible to receive \fIboth\fR |
3753 | value passed to \f(CW\*(C`ev_once\*(C'\fR. Note that it is possible to receive \fIboth\fR |
3605 | a timeout and an io event at the same time \- you probably should give io |
3754 | a timeout and an io event at the same time \- you probably should give io |
3606 | events precedence. |
3755 | events precedence. |
3607 | .Sp |
3756 | .Sp |
3608 | Example: wait up to ten seconds for data to appear on \s-1STDIN_FILENO\s0. |
3757 | Example: wait up to ten seconds for data to appear on \s-1STDIN_FILENO.\s0 |
3609 | .Sp |
3758 | .Sp |
3610 | .Vb 7 |
3759 | .Vb 7 |
3611 | \& static void stdin_ready (int revents, void *arg) |
3760 | \& static void stdin_ready (int revents, void *arg) |
3612 | \& { |
3761 | \& { |
3613 | \& if (revents & EV_READ) |
3762 | \& if (revents & EV_READ) |
… | |
… | |
3629 | .SH "COMMON OR USEFUL IDIOMS (OR BOTH)" |
3778 | .SH "COMMON OR USEFUL IDIOMS (OR BOTH)" |
3630 | .IX Header "COMMON OR USEFUL IDIOMS (OR BOTH)" |
3779 | .IX Header "COMMON OR USEFUL IDIOMS (OR BOTH)" |
3631 | This section explains some common idioms that are not immediately |
3780 | This section explains some common idioms that are not immediately |
3632 | obvious. Note that examples are sprinkled over the whole manual, and this |
3781 | obvious. Note that examples are sprinkled over the whole manual, and this |
3633 | section only contains stuff that wouldn't fit anywhere else. |
3782 | section only contains stuff that wouldn't fit anywhere else. |
3634 | .SS "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0" |
3783 | .SS "\s-1ASSOCIATING CUSTOM DATA WITH A WATCHER\s0" |
3635 | .IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER" |
3784 | .IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER" |
3636 | Each watcher has, by default, a \f(CW\*(C`void *data\*(C'\fR member that you can read |
3785 | Each watcher has, by default, a \f(CW\*(C`void *data\*(C'\fR member that you can read |
3637 | or modify at any time: libev will completely ignore it. This can be used |
3786 | or modify at any time: libev will completely ignore it. This can be used |
3638 | to associate arbitrary data with your watcher. If you need more data and |
3787 | to associate arbitrary data with your watcher. If you need more data and |
3639 | don't want to allocate memory separately and store a pointer to it in that |
3788 | don't want to allocate memory separately and store a pointer to it in that |
… | |
… | |
3665 | \& } |
3814 | \& } |
3666 | .Ve |
3815 | .Ve |
3667 | .PP |
3816 | .PP |
3668 | More interesting and less C\-conformant ways of casting your callback |
3817 | More interesting and less C\-conformant ways of casting your callback |
3669 | function type instead have been omitted. |
3818 | function type instead have been omitted. |
3670 | .SS "\s-1BUILDING\s0 \s-1YOUR\s0 \s-1OWN\s0 \s-1COMPOSITE\s0 \s-1WATCHERS\s0" |
3819 | .SS "\s-1BUILDING YOUR OWN COMPOSITE WATCHERS\s0" |
3671 | .IX Subsection "BUILDING YOUR OWN COMPOSITE WATCHERS" |
3820 | .IX Subsection "BUILDING YOUR OWN COMPOSITE WATCHERS" |
3672 | Another common scenario is to use some data structure with multiple |
3821 | Another common scenario is to use some data structure with multiple |
3673 | embedded watchers, in effect creating your own watcher that combines |
3822 | embedded watchers, in effect creating your own watcher that combines |
3674 | multiple libev event sources into one \*(L"super-watcher\*(R": |
3823 | multiple libev event sources into one \*(L"super-watcher\*(R": |
3675 | .PP |
3824 | .PP |
… | |
… | |
3703 | \& { |
3852 | \& { |
3704 | \& struct my_biggy big = (struct my_biggy *) |
3853 | \& struct my_biggy big = (struct my_biggy *) |
3705 | \& (((char *)w) \- offsetof (struct my_biggy, t2)); |
3854 | \& (((char *)w) \- offsetof (struct my_biggy, t2)); |
3706 | \& } |
3855 | \& } |
3707 | .Ve |
3856 | .Ve |
3708 | .SS "\s-1AVOIDING\s0 \s-1FINISHING\s0 \s-1BEFORE\s0 \s-1RETURNING\s0" |
3857 | .SS "\s-1AVOIDING FINISHING BEFORE RETURNING\s0" |
3709 | .IX Subsection "AVOIDING FINISHING BEFORE RETURNING" |
3858 | .IX Subsection "AVOIDING FINISHING BEFORE RETURNING" |
3710 | Often you have structures like this in event-based programs: |
3859 | Often you have structures like this in event-based programs: |
3711 | .PP |
3860 | .PP |
3712 | .Vb 4 |
3861 | .Vb 4 |
3713 | \& callback () |
3862 | \& callback () |
… | |
… | |
3735 | already been invoked. |
3884 | already been invoked. |
3736 | .PP |
3885 | .PP |
3737 | A common way around all these issues is to make sure that |
3886 | A common way around all these issues is to make sure that |
3738 | \&\f(CW\*(C`start_new_request\*(C'\fR \fIalways\fR returns before the callback is invoked. If |
3887 | \&\f(CW\*(C`start_new_request\*(C'\fR \fIalways\fR returns before the callback is invoked. If |
3739 | \&\f(CW\*(C`start_new_request\*(C'\fR immediately knows the result, it can artificially |
3888 | \&\f(CW\*(C`start_new_request\*(C'\fR immediately knows the result, it can artificially |
3740 | delay invoking the callback by e.g. using a \f(CW\*(C`prepare\*(C'\fR or \f(CW\*(C`idle\*(C'\fR watcher |
3889 | delay invoking the callback by using a \f(CW\*(C`prepare\*(C'\fR or \f(CW\*(C`idle\*(C'\fR watcher for |
3741 | for example, or more sneakily, by reusing an existing (stopped) watcher |
3890 | example, or more sneakily, by reusing an existing (stopped) watcher and |
3742 | and pushing it into the pending queue: |
3891 | pushing it into the pending queue: |
3743 | .PP |
3892 | .PP |
3744 | .Vb 2 |
3893 | .Vb 2 |
3745 | \& ev_set_cb (watcher, callback); |
3894 | \& ev_set_cb (watcher, callback); |
3746 | \& ev_feed_event (EV_A_ watcher, 0); |
3895 | \& ev_feed_event (EV_A_ watcher, 0); |
3747 | .Ve |
3896 | .Ve |
3748 | .PP |
3897 | .PP |
3749 | This way, \f(CW\*(C`start_new_request\*(C'\fR can safely return before the callback is |
3898 | This way, \f(CW\*(C`start_new_request\*(C'\fR can safely return before the callback is |
3750 | invoked, while not delaying callback invocation too much. |
3899 | invoked, while not delaying callback invocation too much. |
3751 | .SS "\s-1MODEL/NESTED\s0 \s-1EVENT\s0 \s-1LOOP\s0 \s-1INVOCATIONS\s0 \s-1AND\s0 \s-1EXIT\s0 \s-1CONDITIONS\s0" |
3900 | .SS "\s-1MODEL/NESTED EVENT LOOP INVOCATIONS AND EXIT CONDITIONS\s0" |
3752 | .IX Subsection "MODEL/NESTED EVENT LOOP INVOCATIONS AND EXIT CONDITIONS" |
3901 | .IX Subsection "MODEL/NESTED EVENT LOOP INVOCATIONS AND EXIT CONDITIONS" |
3753 | Often (especially in \s-1GUI\s0 toolkits) there are places where you have |
3902 | Often (especially in \s-1GUI\s0 toolkits) there are places where you have |
3754 | \&\fImodal\fR interaction, which is most easily implemented by recursively |
3903 | \&\fImodal\fR interaction, which is most easily implemented by recursively |
3755 | invoking \f(CW\*(C`ev_run\*(C'\fR. |
3904 | invoking \f(CW\*(C`ev_run\*(C'\fR. |
3756 | .PP |
3905 | .PP |
3757 | This brings the problem of exiting \- a callback might want to finish the |
3906 | This brings the problem of exiting \- a callback might want to finish the |
3758 | main \f(CW\*(C`ev_run\*(C'\fR call, but not the nested one (e.g. user clicked \*(L"Quit\*(R", but |
3907 | main \f(CW\*(C`ev_run\*(C'\fR call, but not the nested one (e.g. user clicked \*(L"Quit\*(R", but |
3759 | a modal \*(L"Are you sure?\*(R" dialog is still waiting), or just the nested one |
3908 | a modal \*(L"Are you sure?\*(R" dialog is still waiting), or just the nested one |
3760 | and not the main one (e.g. user clocked \*(L"Ok\*(R" in a modal dialog), or some |
3909 | and not the main one (e.g. user clocked \*(L"Ok\*(R" in a modal dialog), or some |
3761 | other combination: In these cases, \f(CW\*(C`ev_break\*(C'\fR will not work alone. |
3910 | other combination: In these cases, a simple \f(CW\*(C`ev_break\*(C'\fR will not work. |
3762 | .PP |
3911 | .PP |
3763 | The solution is to maintain \*(L"break this loop\*(R" variable for each \f(CW\*(C`ev_run\*(C'\fR |
3912 | The solution is to maintain \*(L"break this loop\*(R" variable for each \f(CW\*(C`ev_run\*(C'\fR |
3764 | invocation, and use a loop around \f(CW\*(C`ev_run\*(C'\fR until the condition is |
3913 | invocation, and use a loop around \f(CW\*(C`ev_run\*(C'\fR until the condition is |
3765 | triggered, using \f(CW\*(C`EVRUN_ONCE\*(C'\fR: |
3914 | triggered, using \f(CW\*(C`EVRUN_ONCE\*(C'\fR: |
3766 | .PP |
3915 | .PP |
… | |
… | |
3788 | \& exit_main_loop = 1; |
3937 | \& exit_main_loop = 1; |
3789 | \& |
3938 | \& |
3790 | \& // exit both |
3939 | \& // exit both |
3791 | \& exit_main_loop = exit_nested_loop = 1; |
3940 | \& exit_main_loop = exit_nested_loop = 1; |
3792 | .Ve |
3941 | .Ve |
3793 | .SS "\s-1THREAD\s0 \s-1LOCKING\s0 \s-1EXAMPLE\s0" |
3942 | .SS "\s-1THREAD LOCKING EXAMPLE\s0" |
3794 | .IX Subsection "THREAD LOCKING EXAMPLE" |
3943 | .IX Subsection "THREAD LOCKING EXAMPLE" |
3795 | Here is a fictitious example of how to run an event loop in a different |
3944 | Here is a fictitious example of how to run an event loop in a different |
3796 | thread from where callbacks are being invoked and watchers are |
3945 | thread from where callbacks are being invoked and watchers are |
3797 | created/added/removed. |
3946 | created/added/removed. |
3798 | .PP |
3947 | .PP |
… | |
… | |
3939 | .PP |
4088 | .PP |
3940 | Note that sending the \f(CW\*(C`ev_async\*(C'\fR watcher is required because otherwise |
4089 | Note that sending the \f(CW\*(C`ev_async\*(C'\fR watcher is required because otherwise |
3941 | an event loop currently blocking in the kernel will have no knowledge |
4090 | an event loop currently blocking in the kernel will have no knowledge |
3942 | about the newly added timer. By waking up the loop it will pick up any new |
4091 | about the newly added timer. By waking up the loop it will pick up any new |
3943 | watchers in the next event loop iteration. |
4092 | watchers in the next event loop iteration. |
3944 | .SS "\s-1THREADS\s0, \s-1COROUTINES\s0, \s-1CONTINUATIONS\s0, \s-1QUEUES\s0... \s-1INSTEAD\s0 \s-1OF\s0 \s-1CALLBACKS\s0" |
4093 | .SS "\s-1THREADS, COROUTINES, CONTINUATIONS, QUEUES... INSTEAD OF CALLBACKS\s0" |
3945 | .IX Subsection "THREADS, COROUTINES, CONTINUATIONS, QUEUES... INSTEAD OF CALLBACKS" |
4094 | .IX Subsection "THREADS, COROUTINES, CONTINUATIONS, QUEUES... INSTEAD OF CALLBACKS" |
3946 | While the overhead of a callback that e.g. schedules a thread is small, it |
4095 | While the overhead of a callback that e.g. schedules a thread is small, it |
3947 | is still an overhead. If you embed libev, and your main usage is with some |
4096 | is still an overhead. If you embed libev, and your main usage is with some |
3948 | kind of threads or coroutines, you might want to customise libev so that |
4097 | kind of threads or coroutines, you might want to customise libev so that |
3949 | doesn't need callbacks anymore. |
4098 | doesn't need callbacks anymore. |
… | |
… | |
3971 | .PP |
4120 | .PP |
3972 | .Vb 6 |
4121 | .Vb 6 |
3973 | \& void |
4122 | \& void |
3974 | \& wait_for_event (ev_watcher *w) |
4123 | \& wait_for_event (ev_watcher *w) |
3975 | \& { |
4124 | \& { |
3976 | \& ev_cb_set (w) = current_coro; |
4125 | \& ev_set_cb (w, current_coro); |
3977 | \& switch_to (libev_coro); |
4126 | \& switch_to (libev_coro); |
3978 | \& } |
4127 | \& } |
3979 | .Ve |
4128 | .Ve |
3980 | .PP |
4129 | .PP |
3981 | That basically suspends the coroutine inside \f(CW\*(C`wait_for_event\*(C'\fR and |
4130 | That basically suspends the coroutine inside \f(CW\*(C`wait_for_event\*(C'\fR and |
… | |
… | |
3985 | You can do similar tricks if you have, say, threads with an event queue \- |
4134 | You can do similar tricks if you have, say, threads with an event queue \- |
3986 | instead of storing a coroutine, you store the queue object and instead of |
4135 | instead of storing a coroutine, you store the queue object and instead of |
3987 | switching to a coroutine, you push the watcher onto the queue and notify |
4136 | switching to a coroutine, you push the watcher onto the queue and notify |
3988 | any waiters. |
4137 | any waiters. |
3989 | .PP |
4138 | .PP |
3990 | To embed libev, see \s-1EMBEDDING\s0, but in short, it's easiest to create two |
4139 | To embed libev, see \*(L"\s-1EMBEDDING\*(R"\s0, but in short, it's easiest to create two |
3991 | files, \fImy_ev.h\fR and \fImy_ev.c\fR that include the respective libev files: |
4140 | files, \fImy_ev.h\fR and \fImy_ev.c\fR that include the respective libev files: |
3992 | .PP |
4141 | .PP |
3993 | .Vb 4 |
4142 | .Vb 4 |
3994 | \& // my_ev.h |
4143 | \& // my_ev.h |
3995 | \& #define EV_CB_DECLARE(type) struct my_coro *cb; |
4144 | \& #define EV_CB_DECLARE(type) struct my_coro *cb; |
3996 | \& #define EV_CB_INVOKE(watcher) switch_to ((watcher)\->cb); |
4145 | \& #define EV_CB_INVOKE(watcher) switch_to ((watcher)\->cb) |
3997 | \& #include "../libev/ev.h" |
4146 | \& #include "../libev/ev.h" |
3998 | \& |
4147 | \& |
3999 | \& // my_ev.c |
4148 | \& // my_ev.c |
4000 | \& #define EV_H "my_ev.h" |
4149 | \& #define EV_H "my_ev.h" |
4001 | \& #include "../libev/ev.c" |
4150 | \& #include "../libev/ev.c" |
… | |
… | |
4041 | The normal C \s-1API\s0 should work fine when used from \*(C+: both ev.h and the |
4190 | The normal C \s-1API\s0 should work fine when used from \*(C+: both ev.h and the |
4042 | libev sources can be compiled as \*(C+. Therefore, code that uses the C \s-1API\s0 |
4191 | libev sources can be compiled as \*(C+. Therefore, code that uses the C \s-1API\s0 |
4043 | will work fine. |
4192 | will work fine. |
4044 | .PP |
4193 | .PP |
4045 | Proper exception specifications might have to be added to callbacks passed |
4194 | Proper exception specifications might have to be added to callbacks passed |
4046 | to libev: exceptions may be thrown only from watcher callbacks, all |
4195 | to libev: exceptions may be thrown only from watcher callbacks, all other |
4047 | other callbacks (allocator, syserr, loop acquire/release and periodioc |
4196 | callbacks (allocator, syserr, loop acquire/release and periodic reschedule |
4048 | reschedule callbacks) must not throw exceptions, and might need a \f(CW\*(C`throw |
4197 | callbacks) must not throw exceptions, and might need a \f(CW\*(C`noexcept\*(C'\fR |
4049 | ()\*(C'\fR specification. If you have code that needs to be compiled as both C |
4198 | specification. If you have code that needs to be compiled as both C and |
4050 | and \*(C+ you can use the \f(CW\*(C`EV_THROW\*(C'\fR macro for this: |
4199 | \&\*(C+ you can use the \f(CW\*(C`EV_NOEXCEPT\*(C'\fR macro for this: |
4051 | .PP |
4200 | .PP |
4052 | .Vb 6 |
4201 | .Vb 6 |
4053 | \& static void |
4202 | \& static void |
4054 | \& fatal_error (const char *msg) EV_THROW |
4203 | \& fatal_error (const char *msg) EV_NOEXCEPT |
4055 | \& { |
4204 | \& { |
4056 | \& perror (msg); |
4205 | \& perror (msg); |
4057 | \& abort (); |
4206 | \& abort (); |
4058 | \& } |
4207 | \& } |
4059 | \& |
4208 | \& |
4060 | \& ... |
4209 | \& ... |
4061 | \& ev_set_syserr_cb (fatal_error); |
4210 | \& ev_set_syserr_cb (fatal_error); |
4062 | .Ve |
4211 | .Ve |
4063 | .PP |
4212 | .PP |
4064 | The only \s-1API\s0 functions that can currently throw exceptions are \f(CW\*(C`ev_run\*(C'\fR, |
4213 | The only \s-1API\s0 functions that can currently throw exceptions are \f(CW\*(C`ev_run\*(C'\fR, |
4065 | \&\f(CW\*(C`ev_inoke\*(C'\fR, \f(CW\*(C`ev_invoke_pending\*(C'\fR and \f(CW\*(C`ev_loop_destroy\*(C'\fR (the latter |
4214 | \&\f(CW\*(C`ev_invoke\*(C'\fR, \f(CW\*(C`ev_invoke_pending\*(C'\fR and \f(CW\*(C`ev_loop_destroy\*(C'\fR (the latter |
4066 | because it runs cleanup watchers). |
4215 | because it runs cleanup watchers). |
4067 | .PP |
4216 | .PP |
4068 | Throwing exceptions in watcher callbacks is only supported if libev itself |
4217 | Throwing exceptions in watcher callbacks is only supported if libev itself |
4069 | is compiled with a \*(C+ compiler or your C and \*(C+ environments allow |
4218 | is compiled with a \*(C+ compiler or your C and \*(C+ environments allow |
4070 | throwing exceptions through C libraries (most do). |
4219 | throwing exceptions through C libraries (most do). |
… | |
… | |
4187 | \& void operator() (ev::io &w, int revents) |
4336 | \& void operator() (ev::io &w, int revents) |
4188 | \& { |
4337 | \& { |
4189 | \& ... |
4338 | \& ... |
4190 | \& } |
4339 | \& } |
4191 | \& } |
4340 | \& } |
4192 | \& |
4341 | \& |
4193 | \& myfunctor f; |
4342 | \& myfunctor f; |
4194 | \& |
4343 | \& |
4195 | \& ev::io w; |
4344 | \& ev::io w; |
4196 | \& w.set (&f); |
4345 | \& w.set (&f); |
4197 | .Ve |
4346 | .Ve |
… | |
… | |
4215 | .IX Item "w->set (loop)" |
4364 | .IX Item "w->set (loop)" |
4216 | Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only |
4365 | Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only |
4217 | do this when the watcher is inactive (and not pending either). |
4366 | do this when the watcher is inactive (and not pending either). |
4218 | .IP "w\->set ([arguments])" 4 |
4367 | .IP "w\->set ([arguments])" 4 |
4219 | .IX Item "w->set ([arguments])" |
4368 | .IX Item "w->set ([arguments])" |
4220 | Basically the same as \f(CW\*(C`ev_TYPE_set\*(C'\fR, with the same arguments. Either this |
4369 | Basically the same as \f(CW\*(C`ev_TYPE_set\*(C'\fR (except for \f(CW\*(C`ev::embed\*(C'\fR watchers>), |
4221 | method or a suitable start method must be called at least once. Unlike the |
4370 | with the same arguments. Either this method or a suitable start method |
4222 | C counterpart, an active watcher gets automatically stopped and restarted |
4371 | must be called at least once. Unlike the C counterpart, an active watcher |
4223 | when reconfiguring it with this method. |
4372 | gets automatically stopped and restarted when reconfiguring it with this |
|
|
4373 | method. |
|
|
4374 | .Sp |
|
|
4375 | For \f(CW\*(C`ev::embed\*(C'\fR watchers this method is called \f(CW\*(C`set_embed\*(C'\fR, to avoid |
|
|
4376 | clashing with the \f(CW\*(C`set (loop)\*(C'\fR method. |
4224 | .IP "w\->start ()" 4 |
4377 | .IP "w\->start ()" 4 |
4225 | .IX Item "w->start ()" |
4378 | .IX Item "w->start ()" |
4226 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument, as the |
4379 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument, as the |
4227 | constructor already stores the event loop. |
4380 | constructor already stores the event loop. |
4228 | .IP "w\->start ([arguments])" 4 |
4381 | .IP "w\->start ([arguments])" 4 |
… | |
… | |
4286 | there are additional modules that implement libev-compatible interfaces |
4439 | there are additional modules that implement libev-compatible interfaces |
4287 | to \f(CW\*(C`libadns\*(C'\fR (\f(CW\*(C`EV::ADNS\*(C'\fR, but \f(CW\*(C`AnyEvent::DNS\*(C'\fR is preferred nowadays), |
4440 | to \f(CW\*(C`libadns\*(C'\fR (\f(CW\*(C`EV::ADNS\*(C'\fR, but \f(CW\*(C`AnyEvent::DNS\*(C'\fR is preferred nowadays), |
4288 | \&\f(CW\*(C`Net::SNMP\*(C'\fR (\f(CW\*(C`Net::SNMP::EV\*(C'\fR) and the \f(CW\*(C`libglib\*(C'\fR event core (\f(CW\*(C`Glib::EV\*(C'\fR |
4441 | \&\f(CW\*(C`Net::SNMP\*(C'\fR (\f(CW\*(C`Net::SNMP::EV\*(C'\fR) and the \f(CW\*(C`libglib\*(C'\fR event core (\f(CW\*(C`Glib::EV\*(C'\fR |
4289 | and \f(CW\*(C`EV::Glib\*(C'\fR). |
4442 | and \f(CW\*(C`EV::Glib\*(C'\fR). |
4290 | .Sp |
4443 | .Sp |
4291 | It can be found and installed via \s-1CPAN\s0, its homepage is at |
4444 | It can be found and installed via \s-1CPAN,\s0 its homepage is at |
4292 | <http://software.schmorp.de/pkg/EV>. |
4445 | <http://software.schmorp.de/pkg/EV>. |
4293 | .IP "Python" 4 |
4446 | .IP "Python" 4 |
4294 | .IX Item "Python" |
4447 | .IX Item "Python" |
4295 | Python bindings can be found at <http://code.google.com/p/pyev/>. It |
4448 | Python bindings can be found at <http://code.google.com/p/pyev/>. It |
4296 | seems to be quite complete and well-documented. |
4449 | seems to be quite complete and well-documented. |
… | |
… | |
4304 | Roger Pack reports that using the link order \f(CW\*(C`\-lws2_32 \-lmsvcrt\-ruby\-190\*(C'\fR |
4457 | Roger Pack reports that using the link order \f(CW\*(C`\-lws2_32 \-lmsvcrt\-ruby\-190\*(C'\fR |
4305 | makes rev work even on mingw. |
4458 | makes rev work even on mingw. |
4306 | .IP "Haskell" 4 |
4459 | .IP "Haskell" 4 |
4307 | .IX Item "Haskell" |
4460 | .IX Item "Haskell" |
4308 | A haskell binding to libev is available at |
4461 | A haskell binding to libev is available at |
4309 | http://hackage.haskell.org/cgi\-bin/hackage\-scripts/package/hlibev <http://hackage.haskell.org/cgi-bin/hackage-scripts/package/hlibev>. |
4462 | <http://hackage.haskell.org/cgi\-bin/hackage\-scripts/package/hlibev>. |
4310 | .IP "D" 4 |
4463 | .IP "D" 4 |
4311 | .IX Item "D" |
4464 | .IX Item "D" |
4312 | Leandro Lucarella has written a D language binding (\fIev.d\fR) for libev, to |
4465 | Leandro Lucarella has written a D language binding (\fIev.d\fR) for libev, to |
4313 | be found at <http://www.llucax.com.ar/proj/ev.d/index.html>. |
4466 | be found at <http://www.llucax.com.ar/proj/ev.d/index.html>. |
4314 | .IP "Ocaml" 4 |
4467 | .IP "Ocaml" 4 |
4315 | .IX Item "Ocaml" |
4468 | .IX Item "Ocaml" |
4316 | Erkki Seppala has written Ocaml bindings for libev, to be found at |
4469 | Erkki Seppala has written Ocaml bindings for libev, to be found at |
4317 | http://modeemi.cs.tut.fi/~flux/software/ocaml\-ev/ <http://modeemi.cs.tut.fi/~flux/software/ocaml-ev/>. |
4470 | <http://modeemi.cs.tut.fi/~flux/software/ocaml\-ev/>. |
4318 | .IP "Lua" 4 |
4471 | .IP "Lua" 4 |
4319 | .IX Item "Lua" |
4472 | .IX Item "Lua" |
4320 | Brian Maher has written a partial interface to libev for lua (at the |
4473 | Brian Maher has written a partial interface to libev for lua (at the |
4321 | time of this writing, only \f(CW\*(C`ev_io\*(C'\fR and \f(CW\*(C`ev_timer\*(C'\fR), to be found at |
4474 | time of this writing, only \f(CW\*(C`ev_io\*(C'\fR and \f(CW\*(C`ev_timer\*(C'\fR), to be found at |
4322 | http://github.com/brimworks/lua\-ev <http://github.com/brimworks/lua-ev>. |
4475 | <http://github.com/brimworks/lua\-ev>. |
|
|
4476 | .IP "Javascript" 4 |
|
|
4477 | .IX Item "Javascript" |
|
|
4478 | Node.js (<http://nodejs.org>) uses libev as the underlying event library. |
|
|
4479 | .IP "Others" 4 |
|
|
4480 | .IX Item "Others" |
|
|
4481 | There are others, and I stopped counting. |
4323 | .SH "MACRO MAGIC" |
4482 | .SH "MACRO MAGIC" |
4324 | .IX Header "MACRO MAGIC" |
4483 | .IX Header "MACRO MAGIC" |
4325 | Libev can be compiled with a variety of options, the most fundamental |
4484 | Libev can be compiled with a variety of options, the most fundamental |
4326 | of which is \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines whether (most) |
4485 | of which is \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines whether (most) |
4327 | functions and callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument. |
4486 | functions and callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument. |
… | |
… | |
4410 | .SS "\s-1FILESETS\s0" |
4569 | .SS "\s-1FILESETS\s0" |
4411 | .IX Subsection "FILESETS" |
4570 | .IX Subsection "FILESETS" |
4412 | Depending on what features you need you need to include one or more sets of files |
4571 | Depending on what features you need you need to include one or more sets of files |
4413 | in your application. |
4572 | in your application. |
4414 | .PP |
4573 | .PP |
4415 | \fI\s-1CORE\s0 \s-1EVENT\s0 \s-1LOOP\s0\fR |
4574 | \fI\s-1CORE EVENT LOOP\s0\fR |
4416 | .IX Subsection "CORE EVENT LOOP" |
4575 | .IX Subsection "CORE EVENT LOOP" |
4417 | .PP |
4576 | .PP |
4418 | To include only the libev core (all the \f(CW\*(C`ev_*\*(C'\fR functions), with manual |
4577 | To include only the libev core (all the \f(CW\*(C`ev_*\*(C'\fR functions), with manual |
4419 | configuration (no autoconf): |
4578 | configuration (no autoconf): |
4420 | .PP |
4579 | .PP |
… | |
… | |
4447 | \& ev_vars.h |
4606 | \& ev_vars.h |
4448 | \& ev_wrap.h |
4607 | \& ev_wrap.h |
4449 | \& |
4608 | \& |
4450 | \& ev_win32.c required on win32 platforms only |
4609 | \& ev_win32.c required on win32 platforms only |
4451 | \& |
4610 | \& |
4452 | \& ev_select.c only when select backend is enabled (which is enabled by default) |
4611 | \& ev_select.c only when select backend is enabled |
4453 | \& ev_poll.c only when poll backend is enabled (disabled by default) |
4612 | \& ev_poll.c only when poll backend is enabled |
4454 | \& ev_epoll.c only when the epoll backend is enabled (disabled by default) |
4613 | \& ev_epoll.c only when the epoll backend is enabled |
|
|
4614 | \& ev_linuxaio.c only when the linux aio backend is enabled |
4455 | \& ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
4615 | \& ev_kqueue.c only when the kqueue backend is enabled |
4456 | \& ev_port.c only when the solaris port backend is enabled (disabled by default) |
4616 | \& ev_port.c only when the solaris port backend is enabled |
4457 | .Ve |
4617 | .Ve |
4458 | .PP |
4618 | .PP |
4459 | \&\fIev.c\fR includes the backend files directly when enabled, so you only need |
4619 | \&\fIev.c\fR includes the backend files directly when enabled, so you only need |
4460 | to compile this single file. |
4620 | to compile this single file. |
4461 | .PP |
4621 | .PP |
4462 | \fI\s-1LIBEVENT\s0 \s-1COMPATIBILITY\s0 \s-1API\s0\fR |
4622 | \fI\s-1LIBEVENT COMPATIBILITY API\s0\fR |
4463 | .IX Subsection "LIBEVENT COMPATIBILITY API" |
4623 | .IX Subsection "LIBEVENT COMPATIBILITY API" |
4464 | .PP |
4624 | .PP |
4465 | To include the libevent compatibility \s-1API\s0, also include: |
4625 | To include the libevent compatibility \s-1API,\s0 also include: |
4466 | .PP |
4626 | .PP |
4467 | .Vb 1 |
4627 | .Vb 1 |
4468 | \& #include "event.c" |
4628 | \& #include "event.c" |
4469 | .Ve |
4629 | .Ve |
4470 | .PP |
4630 | .PP |
… | |
… | |
4472 | .PP |
4632 | .PP |
4473 | .Vb 1 |
4633 | .Vb 1 |
4474 | \& #include "event.h" |
4634 | \& #include "event.h" |
4475 | .Ve |
4635 | .Ve |
4476 | .PP |
4636 | .PP |
4477 | in the files that want to use the libevent \s-1API\s0. This also includes \fIev.h\fR. |
4637 | in the files that want to use the libevent \s-1API.\s0 This also includes \fIev.h\fR. |
4478 | .PP |
4638 | .PP |
4479 | You need the following additional files for this: |
4639 | You need the following additional files for this: |
4480 | .PP |
4640 | .PP |
4481 | .Vb 2 |
4641 | .Vb 2 |
4482 | \& event.h |
4642 | \& event.h |
4483 | \& event.c |
4643 | \& event.c |
4484 | .Ve |
4644 | .Ve |
4485 | .PP |
4645 | .PP |
4486 | \fI\s-1AUTOCONF\s0 \s-1SUPPORT\s0\fR |
4646 | \fI\s-1AUTOCONF SUPPORT\s0\fR |
4487 | .IX Subsection "AUTOCONF SUPPORT" |
4647 | .IX Subsection "AUTOCONF SUPPORT" |
4488 | .PP |
4648 | .PP |
4489 | Instead of using \f(CW\*(C`EV_STANDALONE=1\*(C'\fR and providing your configuration in |
4649 | Instead of using \f(CW\*(C`EV_STANDALONE=1\*(C'\fR and providing your configuration in |
4490 | whatever way you want, you can also \f(CW\*(C`m4_include([libev.m4])\*(C'\fR in your |
4650 | whatever way you want, you can also \f(CW\*(C`m4_include([libev.m4])\*(C'\fR in your |
4491 | \&\fIconfigure.ac\fR and leave \f(CW\*(C`EV_STANDALONE\*(C'\fR undefined. \fIev.c\fR will then |
4651 | \&\fIconfigure.ac\fR and leave \f(CW\*(C`EV_STANDALONE\*(C'\fR undefined. \fIev.c\fR will then |
… | |
… | |
4494 | For this of course you need the m4 file: |
4654 | For this of course you need the m4 file: |
4495 | .PP |
4655 | .PP |
4496 | .Vb 1 |
4656 | .Vb 1 |
4497 | \& libev.m4 |
4657 | \& libev.m4 |
4498 | .Ve |
4658 | .Ve |
4499 | .SS "\s-1PREPROCESSOR\s0 \s-1SYMBOLS/MACROS\s0" |
4659 | .SS "\s-1PREPROCESSOR SYMBOLS/MACROS\s0" |
4500 | .IX Subsection "PREPROCESSOR SYMBOLS/MACROS" |
4660 | .IX Subsection "PREPROCESSOR SYMBOLS/MACROS" |
4501 | Libev can be configured via a variety of preprocessor symbols you have to |
4661 | Libev can be configured via a variety of preprocessor symbols you have to |
4502 | define before including (or compiling) any of its files. The default in |
4662 | define before including (or compiling) any of its files. The default in |
4503 | the absence of autoconf is documented for every option. |
4663 | the absence of autoconf is documented for every option. |
4504 | .PP |
4664 | .PP |
4505 | Symbols marked with \*(L"(h)\*(R" do not change the \s-1ABI\s0, and can have different |
4665 | Symbols marked with \*(L"(h)\*(R" do not change the \s-1ABI,\s0 and can have different |
4506 | values when compiling libev vs. including \fIev.h\fR, so it is permissible |
4666 | values when compiling libev vs. including \fIev.h\fR, so it is permissible |
4507 | to redefine them before including \fIev.h\fR without breaking compatibility |
4667 | to redefine them before including \fIev.h\fR without breaking compatibility |
4508 | to a compiled library. All other symbols change the \s-1ABI\s0, which means all |
4668 | to a compiled library. All other symbols change the \s-1ABI,\s0 which means all |
4509 | users of libev and the libev code itself must be compiled with compatible |
4669 | users of libev and the libev code itself must be compiled with compatible |
4510 | settings. |
4670 | settings. |
4511 | .IP "\s-1EV_COMPAT3\s0 (h)" 4 |
4671 | .IP "\s-1EV_COMPAT3\s0 (h)" 4 |
4512 | .IX Item "EV_COMPAT3 (h)" |
4672 | .IX Item "EV_COMPAT3 (h)" |
4513 | Backwards compatibility is a major concern for libev. This is why this |
4673 | Backwards compatibility is a major concern for libev. This is why this |
… | |
… | |
4622 | .IX Item "EV_WIN32_CLOSE_FD(fd)" |
4782 | .IX Item "EV_WIN32_CLOSE_FD(fd)" |
4623 | If programs implement their own fd to handle mapping on win32, then this |
4783 | If programs implement their own fd to handle mapping on win32, then this |
4624 | macro can be used to override the \f(CW\*(C`close\*(C'\fR function, useful to unregister |
4784 | macro can be used to override the \f(CW\*(C`close\*(C'\fR function, useful to unregister |
4625 | file descriptors again. Note that the replacement function has to close |
4785 | file descriptors again. Note that the replacement function has to close |
4626 | the underlying \s-1OS\s0 handle. |
4786 | the underlying \s-1OS\s0 handle. |
|
|
4787 | .IP "\s-1EV_USE_WSASOCKET\s0" 4 |
|
|
4788 | .IX Item "EV_USE_WSASOCKET" |
|
|
4789 | If defined to be \f(CW1\fR, libev will use \f(CW\*(C`WSASocket\*(C'\fR to create its internal |
|
|
4790 | communication socket, which works better in some environments. Otherwise, |
|
|
4791 | the normal \f(CW\*(C`socket\*(C'\fR function will be used, which works better in other |
|
|
4792 | environments. |
4627 | .IP "\s-1EV_USE_POLL\s0" 4 |
4793 | .IP "\s-1EV_USE_POLL\s0" 4 |
4628 | .IX Item "EV_USE_POLL" |
4794 | .IX Item "EV_USE_POLL" |
4629 | If defined to be \f(CW1\fR, libev will compile in support for the \f(CW\*(C`poll\*(C'\fR(2) |
4795 | If defined to be \f(CW1\fR, libev will compile in support for the \f(CW\*(C`poll\*(C'\fR(2) |
4630 | backend. Otherwise it will be enabled on non\-win32 platforms. It |
4796 | backend. Otherwise it will be enabled on non\-win32 platforms. It |
4631 | takes precedence over select. |
4797 | takes precedence over select. |
… | |
… | |
4634 | If defined to be \f(CW1\fR, libev will compile in support for the Linux |
4800 | If defined to be \f(CW1\fR, libev will compile in support for the Linux |
4635 | \&\f(CW\*(C`epoll\*(C'\fR(7) backend. Its availability will be detected at runtime, |
4801 | \&\f(CW\*(C`epoll\*(C'\fR(7) backend. Its availability will be detected at runtime, |
4636 | otherwise another method will be used as fallback. This is the preferred |
4802 | otherwise another method will be used as fallback. This is the preferred |
4637 | backend for GNU/Linux systems. If undefined, it will be enabled if the |
4803 | backend for GNU/Linux systems. If undefined, it will be enabled if the |
4638 | headers indicate GNU/Linux + Glibc 2.4 or newer, otherwise disabled. |
4804 | headers indicate GNU/Linux + Glibc 2.4 or newer, otherwise disabled. |
|
|
4805 | .IP "\s-1EV_USE_LINUXAIO\s0" 4 |
|
|
4806 | .IX Item "EV_USE_LINUXAIO" |
|
|
4807 | If defined to be \f(CW1\fR, libev will compile in support for the Linux |
|
|
4808 | aio backend. Due to it's currenbt limitations it has to be requested |
|
|
4809 | explicitly. If undefined, it will be enabled on linux, otherwise |
|
|
4810 | disabled. |
4639 | .IP "\s-1EV_USE_KQUEUE\s0" 4 |
4811 | .IP "\s-1EV_USE_KQUEUE\s0" 4 |
4640 | .IX Item "EV_USE_KQUEUE" |
4812 | .IX Item "EV_USE_KQUEUE" |
4641 | If defined to be \f(CW1\fR, libev will compile in support for the \s-1BSD\s0 style |
4813 | If defined to be \f(CW1\fR, libev will compile in support for the \s-1BSD\s0 style |
4642 | \&\f(CW\*(C`kqueue\*(C'\fR(2) backend. Its actual availability will be detected at runtime, |
4814 | \&\f(CW\*(C`kqueue\*(C'\fR(2) backend. Its actual availability will be detected at runtime, |
4643 | otherwise another method will be used as fallback. This is the preferred |
4815 | otherwise another method will be used as fallback. This is the preferred |
… | |
… | |
4668 | between threads, that is, threads can be used, but threads never run on |
4840 | between threads, that is, threads can be used, but threads never run on |
4669 | different cpus (or different cpu cores). This reduces dependencies |
4841 | different cpus (or different cpu cores). This reduces dependencies |
4670 | and makes libev faster. |
4842 | and makes libev faster. |
4671 | .IP "\s-1EV_NO_THREADS\s0" 4 |
4843 | .IP "\s-1EV_NO_THREADS\s0" 4 |
4672 | .IX Item "EV_NO_THREADS" |
4844 | .IX Item "EV_NO_THREADS" |
4673 | If defined to be \f(CW1\fR, libev will assume that it will never be called |
4845 | If defined to be \f(CW1\fR, libev will assume that it will never be called from |
4674 | from different threads, which is a stronger assumption than \f(CW\*(C`EV_NO_SMP\*(C'\fR, |
4846 | different threads (that includes signal handlers), which is a stronger |
4675 | above. This reduces dependencies and makes libev faster. |
4847 | assumption than \f(CW\*(C`EV_NO_SMP\*(C'\fR, above. This reduces dependencies and makes |
|
|
4848 | libev faster. |
4676 | .IP "\s-1EV_ATOMIC_T\s0" 4 |
4849 | .IP "\s-1EV_ATOMIC_T\s0" 4 |
4677 | .IX Item "EV_ATOMIC_T" |
4850 | .IX Item "EV_ATOMIC_T" |
4678 | Libev requires an integer type (suitable for storing \f(CW0\fR or \f(CW1\fR) whose |
4851 | Libev requires an integer type (suitable for storing \f(CW0\fR or \f(CW1\fR) whose |
4679 | access is atomic and serialised with respect to other threads or signal |
4852 | access is atomic with respect to other threads or signal contexts. No |
4680 | contexts. No such type is easily found in the C language, so you can |
4853 | such type is easily found in the C language, so you can provide your own |
4681 | provide your own type that you know is safe for your purposes. It is used |
4854 | type that you know is safe for your purposes. It is used both for signal |
4682 | both for signal handler \*(L"locking\*(R" as well as for signal and thread safety |
4855 | handler \*(L"locking\*(R" as well as for signal and thread safety in \f(CW\*(C`ev_async\*(C'\fR |
4683 | in \f(CW\*(C`ev_async\*(C'\fR watchers. |
4856 | watchers. |
4684 | .Sp |
4857 | .Sp |
4685 | In the absence of this define, libev will use \f(CW\*(C`sig_atomic_t volatile\*(C'\fR |
4858 | In the absence of this define, libev will use \f(CW\*(C`sig_atomic_t volatile\*(C'\fR |
4686 | (from \fIsignal.h\fR), which is usually good enough on most platforms, |
4859 | (from \fIsignal.h\fR), which is usually good enough on most platforms. |
4687 | although strictly speaking using a type that also implies a memory fence |
|
|
4688 | is required. |
|
|
4689 | .IP "\s-1EV_H\s0 (h)" 4 |
4860 | .IP "\s-1EV_H\s0 (h)" 4 |
4690 | .IX Item "EV_H (h)" |
4861 | .IX Item "EV_H (h)" |
4691 | The name of the \fIev.h\fR header file used to include it. The default if |
4862 | The name of the \fIev.h\fR header file used to include it. The default if |
4692 | undefined is \f(CW"ev.h"\fR in \fIevent.h\fR, \fIev.c\fR and \fIev++.h\fR. This can be |
4863 | undefined is \f(CW"ev.h"\fR in \fIevent.h\fR, \fIev.c\fR and \fIev++.h\fR. This can be |
4693 | used to virtually rename the \fIev.h\fR header file in case of conflicts. |
4864 | used to virtually rename the \fIev.h\fR header file in case of conflicts. |
… | |
… | |
4732 | all the priorities, so having many of them (hundreds) uses a lot of space |
4903 | all the priorities, so having many of them (hundreds) uses a lot of space |
4733 | and time, so using the defaults of five priorities (\-2 .. +2) is usually |
4904 | and time, so using the defaults of five priorities (\-2 .. +2) is usually |
4734 | fine. |
4905 | fine. |
4735 | .Sp |
4906 | .Sp |
4736 | If your embedding application does not need any priorities, defining these |
4907 | If your embedding application does not need any priorities, defining these |
4737 | both to \f(CW0\fR will save some memory and \s-1CPU\s0. |
4908 | both to \f(CW0\fR will save some memory and \s-1CPU.\s0 |
4738 | .IP "\s-1EV_PERIODIC_ENABLE\s0, \s-1EV_IDLE_ENABLE\s0, \s-1EV_EMBED_ENABLE\s0, \s-1EV_STAT_ENABLE\s0, \s-1EV_PREPARE_ENABLE\s0, \s-1EV_CHECK_ENABLE\s0, \s-1EV_FORK_ENABLE\s0, \s-1EV_SIGNAL_ENABLE\s0, \s-1EV_ASYNC_ENABLE\s0, \s-1EV_CHILD_ENABLE\s0." 4 |
4909 | .IP "\s-1EV_PERIODIC_ENABLE, EV_IDLE_ENABLE, EV_EMBED_ENABLE, EV_STAT_ENABLE, EV_PREPARE_ENABLE, EV_CHECK_ENABLE, EV_FORK_ENABLE, EV_SIGNAL_ENABLE, EV_ASYNC_ENABLE, EV_CHILD_ENABLE.\s0" 4 |
4739 | .IX Item "EV_PERIODIC_ENABLE, EV_IDLE_ENABLE, EV_EMBED_ENABLE, EV_STAT_ENABLE, EV_PREPARE_ENABLE, EV_CHECK_ENABLE, EV_FORK_ENABLE, EV_SIGNAL_ENABLE, EV_ASYNC_ENABLE, EV_CHILD_ENABLE." |
4910 | .IX Item "EV_PERIODIC_ENABLE, EV_IDLE_ENABLE, EV_EMBED_ENABLE, EV_STAT_ENABLE, EV_PREPARE_ENABLE, EV_CHECK_ENABLE, EV_FORK_ENABLE, EV_SIGNAL_ENABLE, EV_ASYNC_ENABLE, EV_CHILD_ENABLE." |
4740 | If undefined or defined to be \f(CW1\fR (and the platform supports it), then |
4911 | If undefined or defined to be \f(CW1\fR (and the platform supports it), then |
4741 | the respective watcher type is supported. If defined to be \f(CW0\fR, then it |
4912 | the respective watcher type is supported. If defined to be \f(CW0\fR, then it |
4742 | is not. Disabling watcher types mainly saves code size. |
4913 | is not. Disabling watcher types mainly saves code size. |
4743 | .IP "\s-1EV_FEATURES\s0" 4 |
4914 | .IP "\s-1EV_FEATURES\s0" 4 |
… | |
… | |
4931 | and the way callbacks are invoked and set. Must expand to a struct member |
5102 | and the way callbacks are invoked and set. Must expand to a struct member |
4932 | definition and a statement, respectively. See the \fIev.h\fR header file for |
5103 | definition and a statement, respectively. See the \fIev.h\fR header file for |
4933 | their default definitions. One possible use for overriding these is to |
5104 | their default definitions. One possible use for overriding these is to |
4934 | avoid the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument in all cases, or to use |
5105 | avoid the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument in all cases, or to use |
4935 | method calls instead of plain function calls in \*(C+. |
5106 | method calls instead of plain function calls in \*(C+. |
4936 | .SS "\s-1EXPORTED\s0 \s-1API\s0 \s-1SYMBOLS\s0" |
5107 | .SS "\s-1EXPORTED API SYMBOLS\s0" |
4937 | .IX Subsection "EXPORTED API SYMBOLS" |
5108 | .IX Subsection "EXPORTED API SYMBOLS" |
4938 | If you need to re-export the \s-1API\s0 (e.g. via a \s-1DLL\s0) and you need a list of |
5109 | If you need to re-export the \s-1API\s0 (e.g. via a \s-1DLL\s0) and you need a list of |
4939 | exported symbols, you can use the provided \fISymbol.*\fR files which list |
5110 | exported symbols, you can use the provided \fISymbol.*\fR files which list |
4940 | all public symbols, one per line: |
5111 | all public symbols, one per line: |
4941 | .PP |
5112 | .PP |
… | |
… | |
4995 | \& #include "ev_cpp.h" |
5166 | \& #include "ev_cpp.h" |
4996 | \& #include "ev.c" |
5167 | \& #include "ev.c" |
4997 | .Ve |
5168 | .Ve |
4998 | .SH "INTERACTION WITH OTHER PROGRAMS, LIBRARIES OR THE ENVIRONMENT" |
5169 | .SH "INTERACTION WITH OTHER PROGRAMS, LIBRARIES OR THE ENVIRONMENT" |
4999 | .IX Header "INTERACTION WITH OTHER PROGRAMS, LIBRARIES OR THE ENVIRONMENT" |
5170 | .IX Header "INTERACTION WITH OTHER PROGRAMS, LIBRARIES OR THE ENVIRONMENT" |
5000 | .SS "\s-1THREADS\s0 \s-1AND\s0 \s-1COROUTINES\s0" |
5171 | .SS "\s-1THREADS AND COROUTINES\s0" |
5001 | .IX Subsection "THREADS AND COROUTINES" |
5172 | .IX Subsection "THREADS AND COROUTINES" |
5002 | \fI\s-1THREADS\s0\fR |
5173 | \fI\s-1THREADS\s0\fR |
5003 | .IX Subsection "THREADS" |
5174 | .IX Subsection "THREADS" |
5004 | .PP |
5175 | .PP |
5005 | All libev functions are reentrant and thread-safe unless explicitly |
5176 | All libev functions are reentrant and thread-safe unless explicitly |
… | |
… | |
5051 | An example use would be to communicate signals or other events that only |
5222 | An example use would be to communicate signals or other events that only |
5052 | work in the default loop by registering the signal watcher with the |
5223 | work in the default loop by registering the signal watcher with the |
5053 | default loop and triggering an \f(CW\*(C`ev_async\*(C'\fR watcher from the default loop |
5224 | default loop and triggering an \f(CW\*(C`ev_async\*(C'\fR watcher from the default loop |
5054 | watcher callback into the event loop interested in the signal. |
5225 | watcher callback into the event loop interested in the signal. |
5055 | .PP |
5226 | .PP |
5056 | See also \*(L"\s-1THREAD\s0 \s-1LOCKING\s0 \s-1EXAMPLE\s0\*(R". |
5227 | See also \*(L"\s-1THREAD LOCKING EXAMPLE\*(R"\s0. |
5057 | .PP |
5228 | .PP |
5058 | \fI\s-1COROUTINES\s0\fR |
5229 | \fI\s-1COROUTINES\s0\fR |
5059 | .IX Subsection "COROUTINES" |
5230 | .IX Subsection "COROUTINES" |
5060 | .PP |
5231 | .PP |
5061 | Libev is very accommodating to coroutines (\*(L"cooperative threads\*(R"): |
5232 | Libev is very accommodating to coroutines (\*(L"cooperative threads\*(R"): |
… | |
… | |
5066 | that you must not do this from \f(CW\*(C`ev_periodic\*(C'\fR reschedule callbacks. |
5237 | that you must not do this from \f(CW\*(C`ev_periodic\*(C'\fR reschedule callbacks. |
5067 | .PP |
5238 | .PP |
5068 | Care has been taken to ensure that libev does not keep local state inside |
5239 | Care has been taken to ensure that libev does not keep local state inside |
5069 | \&\f(CW\*(C`ev_run\*(C'\fR, and other calls do not usually allow for coroutine switches as |
5240 | \&\f(CW\*(C`ev_run\*(C'\fR, and other calls do not usually allow for coroutine switches as |
5070 | they do not call any callbacks. |
5241 | they do not call any callbacks. |
5071 | .SS "\s-1COMPILER\s0 \s-1WARNINGS\s0" |
5242 | .SS "\s-1COMPILER WARNINGS\s0" |
5072 | .IX Subsection "COMPILER WARNINGS" |
5243 | .IX Subsection "COMPILER WARNINGS" |
5073 | Depending on your compiler and compiler settings, you might get no or a |
5244 | Depending on your compiler and compiler settings, you might get no or a |
5074 | lot of warnings when compiling libev code. Some people are apparently |
5245 | lot of warnings when compiling libev code. Some people are apparently |
5075 | scared by this. |
5246 | scared by this. |
5076 | .PP |
5247 | .PP |
… | |
… | |
5128 | .PP |
5299 | .PP |
5129 | If you need, for some reason, empty reports from valgrind for your project |
5300 | If you need, for some reason, empty reports from valgrind for your project |
5130 | I suggest using suppression lists. |
5301 | I suggest using suppression lists. |
5131 | .SH "PORTABILITY NOTES" |
5302 | .SH "PORTABILITY NOTES" |
5132 | .IX Header "PORTABILITY NOTES" |
5303 | .IX Header "PORTABILITY NOTES" |
5133 | .SS "\s-1GNU/LINUX\s0 32 \s-1BIT\s0 \s-1LIMITATIONS\s0" |
5304 | .SS "\s-1GNU/LINUX 32 BIT LIMITATIONS\s0" |
5134 | .IX Subsection "GNU/LINUX 32 BIT LIMITATIONS" |
5305 | .IX Subsection "GNU/LINUX 32 BIT LIMITATIONS" |
5135 | GNU/Linux is the only common platform that supports 64 bit file/large file |
5306 | GNU/Linux is the only common platform that supports 64 bit file/large file |
5136 | interfaces but \fIdisables\fR them by default. |
5307 | interfaces but \fIdisables\fR them by default. |
5137 | .PP |
5308 | .PP |
5138 | That means that libev compiled in the default environment doesn't support |
5309 | That means that libev compiled in the default environment doesn't support |
5139 | files larger than 2GiB or so, which mainly affects \f(CW\*(C`ev_stat\*(C'\fR watchers. |
5310 | files larger than 2GiB or so, which mainly affects \f(CW\*(C`ev_stat\*(C'\fR watchers. |
5140 | .PP |
5311 | .PP |
5141 | Unfortunately, many programs try to work around this GNU/Linux issue |
5312 | Unfortunately, many programs try to work around this GNU/Linux issue |
5142 | by enabling the large file \s-1API\s0, which makes them incompatible with the |
5313 | by enabling the large file \s-1API,\s0 which makes them incompatible with the |
5143 | standard libev compiled for their system. |
5314 | standard libev compiled for their system. |
5144 | .PP |
5315 | .PP |
5145 | Likewise, libev cannot enable the large file \s-1API\s0 itself as this would |
5316 | Likewise, libev cannot enable the large file \s-1API\s0 itself as this would |
5146 | suddenly make it incompatible to the default compile time environment, |
5317 | suddenly make it incompatible to the default compile time environment, |
5147 | i.e. all programs not using special compile switches. |
5318 | i.e. all programs not using special compile switches. |
5148 | .SS "\s-1OS/X\s0 \s-1AND\s0 \s-1DARWIN\s0 \s-1BUGS\s0" |
5319 | .SS "\s-1OS/X AND DARWIN BUGS\s0" |
5149 | .IX Subsection "OS/X AND DARWIN BUGS" |
5320 | .IX Subsection "OS/X AND DARWIN BUGS" |
5150 | The whole thing is a bug if you ask me \- basically any system interface |
5321 | The whole thing is a bug if you ask me \- basically any system interface |
5151 | you touch is broken, whether it is locales, poll, kqueue or even the |
5322 | you touch is broken, whether it is locales, poll, kqueue or even the |
5152 | OpenGL drivers. |
5323 | OpenGL drivers. |
5153 | .PP |
5324 | .PP |
… | |
… | |
5175 | .PP |
5346 | .PP |
5176 | \fI\f(CI\*(C`select\*(C'\fI is buggy\fR |
5347 | \fI\f(CI\*(C`select\*(C'\fI is buggy\fR |
5177 | .IX Subsection "select is buggy" |
5348 | .IX Subsection "select is buggy" |
5178 | .PP |
5349 | .PP |
5179 | All that's left is \f(CW\*(C`select\*(C'\fR, and of course Apple found a way to fuck this |
5350 | All that's left is \f(CW\*(C`select\*(C'\fR, and of course Apple found a way to fuck this |
5180 | one up as well: On \s-1OS/X\s0, \f(CW\*(C`select\*(C'\fR actively limits the number of file |
5351 | one up as well: On \s-1OS/X,\s0 \f(CW\*(C`select\*(C'\fR actively limits the number of file |
5181 | descriptors you can pass in to 1024 \- your program suddenly crashes when |
5352 | descriptors you can pass in to 1024 \- your program suddenly crashes when |
5182 | you use more. |
5353 | you use more. |
5183 | .PP |
5354 | .PP |
5184 | There is an undocumented \*(L"workaround\*(R" for this \- defining |
5355 | There is an undocumented \*(L"workaround\*(R" for this \- defining |
5185 | \&\f(CW\*(C`_DARWIN_UNLIMITED_SELECT\*(C'\fR, which libev tries to use, so select \fIshould\fR |
5356 | \&\f(CW\*(C`_DARWIN_UNLIMITED_SELECT\*(C'\fR, which libev tries to use, so select \fIshould\fR |
5186 | work on \s-1OS/X\s0. |
5357 | work on \s-1OS/X.\s0 |
5187 | .SS "\s-1SOLARIS\s0 \s-1PROBLEMS\s0 \s-1AND\s0 \s-1WORKAROUNDS\s0" |
5358 | .SS "\s-1SOLARIS PROBLEMS AND WORKAROUNDS\s0" |
5188 | .IX Subsection "SOLARIS PROBLEMS AND WORKAROUNDS" |
5359 | .IX Subsection "SOLARIS PROBLEMS AND WORKAROUNDS" |
5189 | \fI\f(CI\*(C`errno\*(C'\fI reentrancy\fR |
5360 | \fI\f(CI\*(C`errno\*(C'\fI reentrancy\fR |
5190 | .IX Subsection "errno reentrancy" |
5361 | .IX Subsection "errno reentrancy" |
5191 | .PP |
5362 | .PP |
5192 | The default compile environment on Solaris is unfortunately so |
5363 | The default compile environment on Solaris is unfortunately so |
… | |
… | |
5209 | great. |
5380 | great. |
5210 | .PP |
5381 | .PP |
5211 | If you can't get it to work, you can try running the program by setting |
5382 | If you can't get it to work, you can try running the program by setting |
5212 | the environment variable \f(CW\*(C`LIBEV_FLAGS=3\*(C'\fR to only allow \f(CW\*(C`poll\*(C'\fR and |
5383 | the environment variable \f(CW\*(C`LIBEV_FLAGS=3\*(C'\fR to only allow \f(CW\*(C`poll\*(C'\fR and |
5213 | \&\f(CW\*(C`select\*(C'\fR backends. |
5384 | \&\f(CW\*(C`select\*(C'\fR backends. |
5214 | .SS "\s-1AIX\s0 \s-1POLL\s0 \s-1BUG\s0" |
5385 | .SS "\s-1AIX POLL BUG\s0" |
5215 | .IX Subsection "AIX POLL BUG" |
5386 | .IX Subsection "AIX POLL BUG" |
5216 | \&\s-1AIX\s0 unfortunately has a broken \f(CW\*(C`poll.h\*(C'\fR header. Libev works around |
5387 | \&\s-1AIX\s0 unfortunately has a broken \f(CW\*(C`poll.h\*(C'\fR header. Libev works around |
5217 | this by trying to avoid the poll backend altogether (i.e. it's not even |
5388 | this by trying to avoid the poll backend altogether (i.e. it's not even |
5218 | compiled in), which normally isn't a big problem as \f(CW\*(C`select\*(C'\fR works fine |
5389 | compiled in), which normally isn't a big problem as \f(CW\*(C`select\*(C'\fR works fine |
5219 | with large bitsets on \s-1AIX\s0, and \s-1AIX\s0 is dead anyway. |
5390 | with large bitsets on \s-1AIX,\s0 and \s-1AIX\s0 is dead anyway. |
5220 | .SS "\s-1WIN32\s0 \s-1PLATFORM\s0 \s-1LIMITATIONS\s0 \s-1AND\s0 \s-1WORKAROUNDS\s0" |
5391 | .SS "\s-1WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS\s0" |
5221 | .IX Subsection "WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS" |
5392 | .IX Subsection "WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS" |
5222 | \fIGeneral issues\fR |
5393 | \fIGeneral issues\fR |
5223 | .IX Subsection "General issues" |
5394 | .IX Subsection "General issues" |
5224 | .PP |
5395 | .PP |
5225 | Win32 doesn't support any of the standards (e.g. \s-1POSIX\s0) that libev |
5396 | Win32 doesn't support any of the standards (e.g. \s-1POSIX\s0) that libev |
… | |
… | |
5294 | \& #define EV_USE_SELECT 1 |
5465 | \& #define EV_USE_SELECT 1 |
5295 | \& #define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */ |
5466 | \& #define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */ |
5296 | .Ve |
5467 | .Ve |
5297 | .PP |
5468 | .PP |
5298 | Note that winsockets handling of fd sets is O(n), so you can easily get a |
5469 | Note that winsockets handling of fd sets is O(n), so you can easily get a |
5299 | complexity in the O(nA\*^X) range when using win32. |
5470 | complexity in the O(nX) range when using win32. |
5300 | .PP |
5471 | .PP |
5301 | \fILimited number of file descriptors\fR |
5472 | \fILimited number of file descriptors\fR |
5302 | .IX Subsection "Limited number of file descriptors" |
5473 | .IX Subsection "Limited number of file descriptors" |
5303 | .PP |
5474 | .PP |
5304 | Windows has numerous arbitrary (and low) limits on things. |
5475 | Windows has numerous arbitrary (and low) limits on things. |
… | |
… | |
5320 | by calling \f(CW\*(C`_setmaxstdio\*(C'\fR, which can increase this limit to \f(CW2048\fR |
5491 | by calling \f(CW\*(C`_setmaxstdio\*(C'\fR, which can increase this limit to \f(CW2048\fR |
5321 | (another arbitrary limit), but is broken in many versions of the Microsoft |
5492 | (another arbitrary limit), but is broken in many versions of the Microsoft |
5322 | runtime libraries. This might get you to about \f(CW512\fR or \f(CW2048\fR sockets |
5493 | runtime libraries. This might get you to about \f(CW512\fR or \f(CW2048\fR sockets |
5323 | (depending on windows version and/or the phase of the moon). To get more, |
5494 | (depending on windows version and/or the phase of the moon). To get more, |
5324 | you need to wrap all I/O functions and provide your own fd management, but |
5495 | you need to wrap all I/O functions and provide your own fd management, but |
5325 | the cost of calling select (O(nA\*^X)) will likely make this unworkable. |
5496 | the cost of calling select (O(nX)) will likely make this unworkable. |
5326 | .SS "\s-1PORTABILITY\s0 \s-1REQUIREMENTS\s0" |
5497 | .SS "\s-1PORTABILITY REQUIREMENTS\s0" |
5327 | .IX Subsection "PORTABILITY REQUIREMENTS" |
5498 | .IX Subsection "PORTABILITY REQUIREMENTS" |
5328 | In addition to a working ISO-C implementation and of course the |
5499 | In addition to a working ISO-C implementation and of course the |
5329 | backend-specific APIs, libev relies on a few additional extensions: |
5500 | backend-specific APIs, libev relies on a few additional extensions: |
5330 | .ie n .IP """void (*)(ev_watcher_type *, int revents)"" must have compatible calling conventions regardless of ""ev_watcher_type *""." 4 |
5501 | .ie n .IP """void (*)(ev_watcher_type *, int revents)"" must have compatible calling conventions regardless of ""ev_watcher_type *""." 4 |
5331 | .el .IP "\f(CWvoid (*)(ev_watcher_type *, int revents)\fR must have compatible calling conventions regardless of \f(CWev_watcher_type *\fR." 4 |
5502 | .el .IP "\f(CWvoid (*)(ev_watcher_type *, int revents)\fR must have compatible calling conventions regardless of \f(CWev_watcher_type *\fR." 4 |
5332 | .IX Item "void (*)(ev_watcher_type *, int revents) must have compatible calling conventions regardless of ev_watcher_type *." |
5503 | .IX Item "void (*)(ev_watcher_type *, int revents) must have compatible calling conventions regardless of ev_watcher_type *." |
5333 | Libev assumes not only that all watcher pointers have the same internal |
5504 | Libev assumes not only that all watcher pointers have the same internal |
5334 | structure (guaranteed by \s-1POSIX\s0 but not by \s-1ISO\s0 C for example), but it also |
5505 | structure (guaranteed by \s-1POSIX\s0 but not by \s-1ISO C\s0 for example), but it also |
5335 | assumes that the same (machine) code can be used to call any watcher |
5506 | assumes that the same (machine) code can be used to call any watcher |
5336 | callback: The watcher callbacks have different type signatures, but libev |
5507 | callback: The watcher callbacks have different type signatures, but libev |
5337 | calls them using an \f(CW\*(C`ev_watcher *\*(C'\fR internally. |
5508 | calls them using an \f(CW\*(C`ev_watcher *\*(C'\fR internally. |
|
|
5509 | .IP "null pointers and integer zero are represented by 0 bytes" 4 |
|
|
5510 | .IX Item "null pointers and integer zero are represented by 0 bytes" |
|
|
5511 | Libev uses \f(CW\*(C`memset\*(C'\fR to initialise structs and arrays to \f(CW0\fR bytes, and |
|
|
5512 | relies on this setting pointers and integers to null. |
5338 | .IP "pointer accesses must be thread-atomic" 4 |
5513 | .IP "pointer accesses must be thread-atomic" 4 |
5339 | .IX Item "pointer accesses must be thread-atomic" |
5514 | .IX Item "pointer accesses must be thread-atomic" |
5340 | Accessing a pointer value must be atomic, it must both be readable and |
5515 | Accessing a pointer value must be atomic, it must both be readable and |
5341 | writable in one piece \- this is the case on all current architectures. |
5516 | writable in one piece \- this is the case on all current architectures. |
5342 | .ie n .IP """sig_atomic_t volatile"" must be thread-atomic as well" 4 |
5517 | .ie n .IP """sig_atomic_t volatile"" must be thread-atomic as well" 4 |
… | |
… | |
5355 | thread\*(R" or will block signals process-wide, both behaviours would |
5530 | thread\*(R" or will block signals process-wide, both behaviours would |
5356 | be compatible with libev. Interaction between \f(CW\*(C`sigprocmask\*(C'\fR and |
5531 | be compatible with libev. Interaction between \f(CW\*(C`sigprocmask\*(C'\fR and |
5357 | \&\f(CW\*(C`pthread_sigmask\*(C'\fR could complicate things, however. |
5532 | \&\f(CW\*(C`pthread_sigmask\*(C'\fR could complicate things, however. |
5358 | .Sp |
5533 | .Sp |
5359 | The most portable way to handle signals is to block signals in all threads |
5534 | The most portable way to handle signals is to block signals in all threads |
5360 | except the initial one, and run the default loop in the initial thread as |
5535 | except the initial one, and run the signal handling loop in the initial |
5361 | well. |
5536 | thread as well. |
5362 | .ie n .IP """long"" must be large enough for common memory allocation sizes" 4 |
5537 | .ie n .IP """long"" must be large enough for common memory allocation sizes" 4 |
5363 | .el .IP "\f(CWlong\fR must be large enough for common memory allocation sizes" 4 |
5538 | .el .IP "\f(CWlong\fR must be large enough for common memory allocation sizes" 4 |
5364 | .IX Item "long must be large enough for common memory allocation sizes" |
5539 | .IX Item "long must be large enough for common memory allocation sizes" |
5365 | To improve portability and simplify its \s-1API\s0, libev uses \f(CW\*(C`long\*(C'\fR internally |
5540 | To improve portability and simplify its \s-1API,\s0 libev uses \f(CW\*(C`long\*(C'\fR internally |
5366 | instead of \f(CW\*(C`size_t\*(C'\fR when allocating its data structures. On non-POSIX |
5541 | instead of \f(CW\*(C`size_t\*(C'\fR when allocating its data structures. On non-POSIX |
5367 | systems (Microsoft...) this might be unexpectedly low, but is still at |
5542 | systems (Microsoft...) this might be unexpectedly low, but is still at |
5368 | least 31 bits everywhere, which is enough for hundreds of millions of |
5543 | least 31 bits everywhere, which is enough for hundreds of millions of |
5369 | watchers. |
5544 | watchers. |
5370 | .ie n .IP """double"" must hold a time value in seconds with enough accuracy" 4 |
5545 | .ie n .IP """double"" must hold a time value in seconds with enough accuracy" 4 |
… | |
… | |
5372 | .IX Item "double must hold a time value in seconds with enough accuracy" |
5547 | .IX Item "double must hold a time value in seconds with enough accuracy" |
5373 | The type \f(CW\*(C`double\*(C'\fR is used to represent timestamps. It is required to |
5548 | The type \f(CW\*(C`double\*(C'\fR is used to represent timestamps. It is required to |
5374 | have at least 51 bits of mantissa (and 9 bits of exponent), which is |
5549 | have at least 51 bits of mantissa (and 9 bits of exponent), which is |
5375 | good enough for at least into the year 4000 with millisecond accuracy |
5550 | good enough for at least into the year 4000 with millisecond accuracy |
5376 | (the design goal for libev). This requirement is overfulfilled by |
5551 | (the design goal for libev). This requirement is overfulfilled by |
5377 | implementations using \s-1IEEE\s0 754, which is basically all existing ones. |
5552 | implementations using \s-1IEEE 754,\s0 which is basically all existing ones. |
5378 | .Sp |
5553 | .Sp |
5379 | With \s-1IEEE\s0 754 doubles, you get microsecond accuracy until at least the |
5554 | With \s-1IEEE 754\s0 doubles, you get microsecond accuracy until at least the |
5380 | year 2255 (and millisecond accuracy till the year 287396 \- by then, libev |
5555 | year 2255 (and millisecond accuracy till the year 287396 \- by then, libev |
5381 | is either obsolete or somebody patched it to use \f(CW\*(C`long double\*(C'\fR or |
5556 | is either obsolete or somebody patched it to use \f(CW\*(C`long double\*(C'\fR or |
5382 | something like that, just kidding). |
5557 | something like that, just kidding). |
5383 | .PP |
5558 | .PP |
5384 | If you know of other additional requirements drop me a note. |
5559 | If you know of other additional requirements drop me a note. |
… | |
… | |
5446 | calls in the current loop iteration and the loop is currently |
5621 | calls in the current loop iteration and the loop is currently |
5447 | blocked. Checking for async and signal events involves iterating over all |
5622 | blocked. Checking for async and signal events involves iterating over all |
5448 | running async watchers or all signal numbers. |
5623 | running async watchers or all signal numbers. |
5449 | .SH "PORTING FROM LIBEV 3.X TO 4.X" |
5624 | .SH "PORTING FROM LIBEV 3.X TO 4.X" |
5450 | .IX Header "PORTING FROM LIBEV 3.X TO 4.X" |
5625 | .IX Header "PORTING FROM LIBEV 3.X TO 4.X" |
5451 | The major version 4 introduced some incompatible changes to the \s-1API\s0. |
5626 | The major version 4 introduced some incompatible changes to the \s-1API.\s0 |
5452 | .PP |
5627 | .PP |
5453 | At the moment, the \f(CW\*(C`ev.h\*(C'\fR header file provides compatibility definitions |
5628 | At the moment, the \f(CW\*(C`ev.h\*(C'\fR header file provides compatibility definitions |
5454 | for all changes, so most programs should still compile. The compatibility |
5629 | for all changes, so most programs should still compile. The compatibility |
5455 | layer might be removed in later versions of libev, so better update to the |
5630 | layer might be removed in later versions of libev, so better update to the |
5456 | new \s-1API\s0 early than late. |
5631 | new \s-1API\s0 early than late. |
5457 | .ie n .IP """EV_COMPAT3"" backwards compatibility mechanism" 4 |
5632 | .ie n .IP """EV_COMPAT3"" backwards compatibility mechanism" 4 |
5458 | .el .IP "\f(CWEV_COMPAT3\fR backwards compatibility mechanism" 4 |
5633 | .el .IP "\f(CWEV_COMPAT3\fR backwards compatibility mechanism" 4 |
5459 | .IX Item "EV_COMPAT3 backwards compatibility mechanism" |
5634 | .IX Item "EV_COMPAT3 backwards compatibility mechanism" |
5460 | The backward compatibility mechanism can be controlled by |
5635 | The backward compatibility mechanism can be controlled by |
5461 | \&\f(CW\*(C`EV_COMPAT3\*(C'\fR. See \*(L"\s-1MACROS\s0\*(R" in \s-1PREPROCESSOR\s0 \s-1SYMBOLS\s0 in the \s-1EMBEDDING\s0 |
5636 | \&\f(CW\*(C`EV_COMPAT3\*(C'\fR. See \*(L"\s-1PREPROCESSOR SYMBOLS/MACROS\*(R"\s0 in the \*(L"\s-1EMBEDDING\*(R"\s0 |
5462 | section. |
5637 | section. |
5463 | .ie n .IP """ev_default_destroy"" and ""ev_default_fork"" have been removed" 4 |
5638 | .ie n .IP """ev_default_destroy"" and ""ev_default_fork"" have been removed" 4 |
5464 | .el .IP "\f(CWev_default_destroy\fR and \f(CWev_default_fork\fR have been removed" 4 |
5639 | .el .IP "\f(CWev_default_destroy\fR and \f(CWev_default_fork\fR have been removed" 4 |
5465 | .IX Item "ev_default_destroy and ev_default_fork have been removed" |
5640 | .IX Item "ev_default_destroy and ev_default_fork have been removed" |
5466 | These calls can be replaced easily by their \f(CW\*(C`ev_loop_xxx\*(C'\fR counterparts: |
5641 | These calls can be replaced easily by their \f(CW\*(C`ev_loop_xxx\*(C'\fR counterparts: |
… | |
… | |
5506 | .SH "GLOSSARY" |
5681 | .SH "GLOSSARY" |
5507 | .IX Header "GLOSSARY" |
5682 | .IX Header "GLOSSARY" |
5508 | .IP "active" 4 |
5683 | .IP "active" 4 |
5509 | .IX Item "active" |
5684 | .IX Item "active" |
5510 | A watcher is active as long as it has been started and not yet stopped. |
5685 | A watcher is active as long as it has been started and not yet stopped. |
5511 | See \*(L"\s-1WATCHER\s0 \s-1STATES\s0\*(R" for details. |
5686 | See \*(L"\s-1WATCHER STATES\*(R"\s0 for details. |
5512 | .IP "application" 4 |
5687 | .IP "application" 4 |
5513 | .IX Item "application" |
5688 | .IX Item "application" |
5514 | In this document, an application is whatever is using libev. |
5689 | In this document, an application is whatever is using libev. |
5515 | .IP "backend" 4 |
5690 | .IP "backend" 4 |
5516 | .IX Item "backend" |
5691 | .IX Item "backend" |
… | |
… | |
5543 | The model used to describe how an event loop handles and processes |
5718 | The model used to describe how an event loop handles and processes |
5544 | watchers and events. |
5719 | watchers and events. |
5545 | .IP "pending" 4 |
5720 | .IP "pending" 4 |
5546 | .IX Item "pending" |
5721 | .IX Item "pending" |
5547 | A watcher is pending as soon as the corresponding event has been |
5722 | A watcher is pending as soon as the corresponding event has been |
5548 | detected. See \*(L"\s-1WATCHER\s0 \s-1STATES\s0\*(R" for details. |
5723 | detected. See \*(L"\s-1WATCHER STATES\*(R"\s0 for details. |
5549 | .IP "real time" 4 |
5724 | .IP "real time" 4 |
5550 | .IX Item "real time" |
5725 | .IX Item "real time" |
5551 | The physical time that is observed. It is apparently strictly monotonic :) |
5726 | The physical time that is observed. It is apparently strictly monotonic :) |
5552 | .IP "wall-clock time" 4 |
5727 | .IP "wall-clock time" 4 |
5553 | .IX Item "wall-clock time" |
5728 | .IX Item "wall-clock time" |