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126 | .IX Title "LIBEV 3" |
135 | .IX Title "LIBEV 3" |
127 | .TH LIBEV 3 "2012-04-03" "libev-4.11" "libev - high performance full featured event loop" |
136 | .TH LIBEV 3 "2019-06-25" "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 |
129 | .\" way too many mistakes in technical documents. |
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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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367 | current system. To find which embeddable backends might be supported on |
376 | current system. To find which embeddable backends might be supported on |
368 | the current system, you would need to look at \f(CW\*(C`ev_embeddable_backends () |
377 | the current system, you would need to look at \f(CW\*(C`ev_embeddable_backends () |
369 | & ev_supported_backends ()\*(C'\fR, likewise for recommended ones. |
378 | & ev_supported_backends ()\*(C'\fR, likewise for recommended ones. |
370 | .Sp |
379 | .Sp |
371 | See the description of \f(CW\*(C`ev_embed\*(C'\fR watchers for more info. |
380 | See the description of \f(CW\*(C`ev_embed\*(C'\fR watchers for more info. |
372 | .IP "ev_set_allocator (void *(*cb)(void *ptr, long size))" 4 |
381 | .IP "ev_set_allocator (void *(*cb)(void *ptr, long size) throw ())" 4 |
373 | .IX Item "ev_set_allocator (void *(*cb)(void *ptr, long size))" |
382 | .IX Item "ev_set_allocator (void *(*cb)(void *ptr, long size) throw ())" |
374 | Sets the allocation function to use (the prototype is similar \- the |
383 | Sets the allocation function to use (the prototype is similar \- the |
375 | semantics are identical to the \f(CW\*(C`realloc\*(C'\fR C89/SuS/POSIX function). It is |
384 | semantics are identical to the \f(CW\*(C`realloc\*(C'\fR C89/SuS/POSIX function). It is |
376 | used to allocate and free memory (no surprises here). If it returns zero |
385 | used to allocate and free memory (no surprises here). If it returns zero |
377 | when memory needs to be allocated (\f(CW\*(C`size != 0\*(C'\fR), the library might abort |
386 | when memory needs to be allocated (\f(CW\*(C`size != 0\*(C'\fR), the library might abort |
378 | or take some potentially destructive action. |
387 | or take some potentially destructive action. |
… | |
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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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404 | \& } |
435 | \& } |
405 | \& |
436 | \& |
406 | \& ... |
437 | \& ... |
407 | \& ev_set_allocator (persistent_realloc); |
438 | \& ev_set_allocator (persistent_realloc); |
408 | .Ve |
439 | .Ve |
409 | .IP "ev_set_syserr_cb (void (*cb)(const char *msg))" 4 |
440 | .IP "ev_set_syserr_cb (void (*cb)(const char *msg) throw ())" 4 |
410 | .IX Item "ev_set_syserr_cb (void (*cb)(const char *msg))" |
441 | .IX Item "ev_set_syserr_cb (void (*cb)(const char *msg) throw ())" |
411 | Set the callback function to call on a retryable system call error (such |
442 | Set the callback function to call on a retryable system call error (such |
412 | as failed select, poll, epoll_wait). The message is a printable string |
443 | as failed select, poll, epoll_wait). The message is a printable string |
413 | indicating the system call or subsystem causing the problem. If this |
444 | indicating the system call or subsystem causing the problem. If this |
414 | callback is set, then libev will expect it to remedy the situation, no |
445 | callback is set, then libev will expect it to remedy the situation, no |
415 | matter what, when it returns. That is, libev will generally retry the |
446 | matter what, when it returns. That is, libev will generally retry the |
… | |
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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 |
… | |
… | |
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 \s-1AIO\s0 (\fInot\fR \f(CWaio(7)\fR but \f(CWio_submit(2)\fR) event interface available in post\-4.18 kernels (but libev |
|
|
707 | only tries to use it in 4.19+). |
|
|
708 | .Sp |
|
|
709 | This is another Linux train wreck of an event interface. |
|
|
710 | .Sp |
|
|
711 | If this backend works for you (as of this writing, it was very |
|
|
712 | experimental), it is the best event interface available on Linux and might |
|
|
713 | be well worth enabling it \- if it isn't available in your kernel this will |
|
|
714 | be detected and this backend will be skipped. |
|
|
715 | .Sp |
|
|
716 | This backend can batch oneshot requests and supports a user-space ring |
|
|
717 | buffer to receive events. It also doesn't suffer from most of the design |
|
|
718 | problems of epoll (such as not being able to remove event sources from |
|
|
719 | the epoll set), and generally sounds too good to be true. Because, this |
|
|
720 | being the Linux kernel, of course it suffers from a whole new set of |
|
|
721 | limitations, forcing you to fall back to epoll, inheriting all its design |
|
|
722 | issues. |
|
|
723 | .Sp |
|
|
724 | For one, it is not easily embeddable (but probably could be done using |
|
|
725 | an event fd at some extra overhead). It also is subject to a system wide |
|
|
726 | limit that can be configured in \fI/proc/sys/fs/aio\-max\-nr\fR. If no \s-1AIO\s0 |
|
|
727 | requests are left, this backend will be skipped during initialisation, and |
|
|
728 | will switch to epoll when the loop is active. |
|
|
729 | .Sp |
|
|
730 | Most problematic in practice, however, is that not all file descriptors |
|
|
731 | work with it. For example, in Linux 5.1, \s-1TCP\s0 sockets, pipes, event fds, |
|
|
732 | files, \fI/dev/null\fR and many others are supported, but ttys do not work |
|
|
733 | properly (a known bug that the kernel developers don't care about, see |
|
|
734 | <https://lore.kernel.org/patchwork/patch/1047453/>), so this is not |
|
|
735 | (yet?) a generic event polling interface. |
|
|
736 | .Sp |
|
|
737 | Overall, it seems the Linux developers just don't want it to have a |
|
|
738 | generic event handling mechanism other than \f(CW\*(C`select\*(C'\fR or \f(CW\*(C`poll\*(C'\fR. |
|
|
739 | .Sp |
|
|
740 | To work around all these problem, the current version of libev uses its |
|
|
741 | epoll backend as a fallback for file descriptor types that do not work. Or |
|
|
742 | falls back completely to epoll if the kernel acts up. |
666 | .Sp |
743 | .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 |
744 | 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. |
745 | \&\f(CW\*(C`EVBACKEND_POLL\*(C'\fR. |
669 | .ie n .IP """EVBACKEND_KQUEUE"" (value 8, most \s-1BSD\s0 clones)" 4 |
746 | .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 |
747 | .el .IP "\f(CWEVBACKEND_KQUEUE\fR (value 8, most \s-1BSD\s0 clones)" 4 |
671 | .IX Item "EVBACKEND_KQUEUE (value 8, most BSD clones)" |
748 | .IX Item "EVBACKEND_KQUEUE (value 8, most BSD clones)" |
672 | Kqueue deserves special mention, as at the time of this writing, it |
749 | Kqueue deserves special mention, as at the time this backend was |
673 | was broken on all BSDs except NetBSD (usually it doesn't work reliably |
750 | implemented, it was broken on all BSDs except NetBSD (usually it doesn't |
674 | with anything but sockets and pipes, except on Darwin, where of course |
751 | work reliably with anything but sockets and pipes, except on Darwin, |
675 | it's completely useless). Unlike epoll, however, whose brokenness |
752 | where of course it's completely useless). Unlike epoll, however, whose |
676 | is by design, these kqueue bugs can (and eventually will) be fixed |
753 | brokenness is by design, these kqueue bugs can be (and mostly have been) |
677 | without \s-1API\s0 changes to existing programs. For this reason it's not being |
754 | fixed without \s-1API\s0 changes to existing programs. For this reason it's not |
678 | \&\*(L"auto-detected\*(R" unless you explicitly specify it in the flags (i.e. using |
755 | being \*(L"auto-detected\*(R" on all platforms unless you explicitly specify it |
679 | \&\f(CW\*(C`EVBACKEND_KQUEUE\*(C'\fR) or libev was compiled on a known-to-be-good (\-enough) |
756 | in the flags (i.e. using \f(CW\*(C`EVBACKEND_KQUEUE\*(C'\fR) or libev was compiled on a |
680 | system like NetBSD. |
757 | known-to-be-good (\-enough) system like NetBSD. |
681 | .Sp |
758 | .Sp |
682 | You still can embed kqueue into a normal poll or select backend and use it |
759 | You still can embed kqueue into a normal poll or select backend and use it |
683 | only for sockets (after having made sure that sockets work with kqueue on |
760 | only for sockets (after having made sure that sockets work with kqueue on |
684 | the target platform). See \f(CW\*(C`ev_embed\*(C'\fR watchers for more info. |
761 | the target platform). See \f(CW\*(C`ev_embed\*(C'\fR watchers for more info. |
685 | .Sp |
762 | .Sp |
686 | It scales in the same way as the epoll backend, but the interface to the |
763 | It scales in the same way as the epoll backend, but the interface to the |
687 | kernel is more efficient (which says nothing about its actual speed, of |
764 | 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 |
765 | 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 |
766 | 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 |
767 | 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 |
768 | might have to leak fds on fork, but it's more sane than epoll) and it |
692 | drops fds silently in similarly hard-to-detect cases |
769 | drops fds silently in similarly hard-to-detect cases. |
693 | .Sp |
770 | .Sp |
694 | This backend usually performs well under most conditions. |
771 | This backend usually performs well under most conditions. |
695 | .Sp |
772 | .Sp |
696 | While nominally embeddable in other event loops, this doesn't work |
773 | 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 |
774 | 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 |
775 | 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 |
776 | (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 |
777 | (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. |
778 | also broken on \s-1OS X\s0)) and, did I mention it, using it only for sockets. |
702 | .Sp |
779 | .Sp |
703 | This backend maps \f(CW\*(C`EV_READ\*(C'\fR into an \f(CW\*(C`EVFILT_READ\*(C'\fR kevent with |
780 | 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 |
781 | \&\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. |
782 | \&\f(CW\*(C`NOTE_EOF\*(C'\fR. |
706 | .ie n .IP """EVBACKEND_DEVPOLL"" (value 16, Solaris 8)" 4 |
783 | .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 |
787 | 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 |
788 | and is not embeddable, which would limit the usefulness of this backend |
712 | immensely. |
789 | immensely. |
713 | .ie n .IP """EVBACKEND_PORT"" (value 32, Solaris 10)" 4 |
790 | .ie n .IP """EVBACKEND_PORT"" (value 32, Solaris 10)" 4 |
714 | .el .IP "\f(CWEVBACKEND_PORT\fR (value 32, Solaris 10)" 4 |
791 | .el .IP "\f(CWEVBACKEND_PORT\fR (value 32, Solaris 10)" 4 |
715 | .IX Item "EVBACKEND_PORT (value 32, Solaris 10)" |
792 | .IX Item "EVBACKEND_PORT (value 32, Solaris 10)" |
716 | This uses the Solaris 10 event port mechanism. As with everything on Solaris, |
793 | 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)). |
794 | it's really slow, but it still scales very well (O(active_fds)). |
718 | .Sp |
795 | .Sp |
719 | While this backend scales well, it requires one system call per active |
796 | 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 |
797 | file descriptor per loop iteration. For small and medium numbers of file |
… | |
… | |
774 | used if available. |
851 | used if available. |
775 | .Sp |
852 | .Sp |
776 | .Vb 1 |
853 | .Vb 1 |
777 | \& struct ev_loop *loop = ev_loop_new (ev_recommended_backends () | EVBACKEND_KQUEUE); |
854 | \& struct ev_loop *loop = ev_loop_new (ev_recommended_backends () | EVBACKEND_KQUEUE); |
778 | .Ve |
855 | .Ve |
|
|
856 | .Sp |
|
|
857 | Example: Similarly, on linux, you mgiht want to take advantage of the |
|
|
858 | linux aio backend if possible, but fall back to something else if that |
|
|
859 | isn't available. |
|
|
860 | .Sp |
|
|
861 | .Vb 1 |
|
|
862 | \& struct ev_loop *loop = ev_loop_new (ev_recommended_backends () | EVBACKEND_LINUXAIO); |
|
|
863 | .Ve |
779 | .RE |
864 | .RE |
780 | .IP "ev_loop_destroy (loop)" 4 |
865 | .IP "ev_loop_destroy (loop)" 4 |
781 | .IX Item "ev_loop_destroy (loop)" |
866 | .IX Item "ev_loop_destroy (loop)" |
782 | Destroys an event loop object (frees all memory and kernel state |
867 | 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 |
868 | 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. |
884 | 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 |
885 | 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. |
886 | and \f(CW\*(C`ev_loop_destroy\*(C'\fR. |
802 | .IP "ev_loop_fork (loop)" 4 |
887 | .IP "ev_loop_fork (loop)" 4 |
803 | .IX Item "ev_loop_fork (loop)" |
888 | .IX Item "ev_loop_fork (loop)" |
804 | This function sets a flag that causes subsequent \f(CW\*(C`ev_run\*(C'\fR iterations to |
889 | 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 |
890 | 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 |
891 | 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 |
892 | 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. |
893 | sense after forking, in the child process. You \fImust\fR call it (or use |
|
|
894 | \&\f(CW\*(C`EVFLAG_FORKCHECK\*(C'\fR) in the child before resuming or calling \f(CW\*(C`ev_run\*(C'\fR. |
809 | .Sp |
895 | .Sp |
|
|
896 | In addition, if you want to reuse a loop (via this function or |
|
|
897 | \&\f(CW\*(C`EVFLAG_FORKCHECK\*(C'\fR), you \fIalso\fR have to ignore \f(CW\*(C`SIGPIPE\*(C'\fR. |
|
|
898 | .Sp |
810 | Again, you \fIhave\fR to call it on \fIany\fR loop that you want to re-use after |
899 | 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 |
900 | 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 |
901 | because some kernel interfaces *cough* \fIkqueue\fR *cough* do funny things |
813 | during fork. |
902 | during fork. |
814 | .Sp |
903 | .Sp |
815 | On the other hand, you only need to call this function in the child |
904 | On the other hand, you only need to call this function in the child |
… | |
… | |
1140 | this callback instead. This is useful, for example, when you want to |
1229 | this callback instead. This is useful, for example, when you want to |
1141 | invoke the actual watchers inside another context (another thread etc.). |
1230 | invoke the actual watchers inside another context (another thread etc.). |
1142 | .Sp |
1231 | .Sp |
1143 | If you want to reset the callback, use \f(CW\*(C`ev_invoke_pending\*(C'\fR as new |
1232 | If you want to reset the callback, use \f(CW\*(C`ev_invoke_pending\*(C'\fR as new |
1144 | callback. |
1233 | callback. |
1145 | .IP "ev_set_loop_release_cb (loop, void (*release)(\s-1EV_P\s0), void (*acquire)(\s-1EV_P\s0))" 4 |
1234 | .IP "ev_set_loop_release_cb (loop, void (*release)(\s-1EV_P\s0) throw (), void (*acquire)(\s-1EV_P\s0) throw ())" 4 |
1146 | .IX Item "ev_set_loop_release_cb (loop, void (*release)(EV_P), void (*acquire)(EV_P))" |
1235 | .IX Item "ev_set_loop_release_cb (loop, void (*release)(EV_P) throw (), void (*acquire)(EV_P) throw ())" |
1147 | Sometimes you want to share the same loop between multiple threads. This |
1236 | Sometimes you want to share the same loop between multiple threads. This |
1148 | can be done relatively simply by putting mutex_lock/unlock calls around |
1237 | can be done relatively simply by putting mutex_lock/unlock calls around |
1149 | each call to a libev function. |
1238 | each call to a libev function. |
1150 | .Sp |
1239 | .Sp |
1151 | However, \f(CW\*(C`ev_run\*(C'\fR can run an indefinite time, so it is not feasible |
1240 | However, \f(CW\*(C`ev_run\*(C'\fR can run an indefinite time, so it is not feasible |
… | |
… | |
1299 | .PD 0 |
1388 | .PD 0 |
1300 | .ie n .IP """EV_CHECK""" 4 |
1389 | .ie n .IP """EV_CHECK""" 4 |
1301 | .el .IP "\f(CWEV_CHECK\fR" 4 |
1390 | .el .IP "\f(CWEV_CHECK\fR" 4 |
1302 | .IX Item "EV_CHECK" |
1391 | .IX Item "EV_CHECK" |
1303 | .PD |
1392 | .PD |
1304 | All \f(CW\*(C`ev_prepare\*(C'\fR watchers are invoked just \fIbefore\fR \f(CW\*(C`ev_run\*(C'\fR starts |
1393 | 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 |
1394 | 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 |
1395 | just after \f(CW\*(C`ev_run\*(C'\fR has gathered them, but before it queues any callbacks |
|
|
1396 | for any received events. That means \f(CW\*(C`ev_prepare\*(C'\fR watchers are the last |
|
|
1397 | watchers invoked before the event loop sleeps or polls for new events, and |
|
|
1398 | \&\f(CW\*(C`ev_check\*(C'\fR watchers will be invoked before any other watchers of the same |
|
|
1399 | or lower priority within an event loop iteration. |
|
|
1400 | .Sp |
1307 | received events. Callbacks of both watcher types can start and stop as |
1401 | 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 |
1402 | 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 |
1403 | \&\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). |
1404 | blocking). |
1311 | .ie n .IP """EV_EMBED""" 4 |
1405 | .ie n .IP """EV_EMBED""" 4 |
1312 | .el .IP "\f(CWEV_EMBED\fR" 4 |
1406 | .el .IP "\f(CWEV_EMBED\fR" 4 |
1313 | .IX Item "EV_EMBED" |
1407 | .IX Item "EV_EMBED" |
1314 | The embedded event loop specified in the \f(CW\*(C`ev_embed\*(C'\fR watcher needs attention. |
1408 | The embedded event loop specified in the \f(CW\*(C`ev_embed\*(C'\fR watcher needs attention. |
1315 | .ie n .IP """EV_FORK""" 4 |
1409 | .ie n .IP """EV_FORK""" 4 |
… | |
… | |
1344 | bug in your program. |
1438 | bug in your program. |
1345 | .Sp |
1439 | .Sp |
1346 | Libev will usually signal a few \*(L"dummy\*(R" events together with an error, for |
1440 | 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 |
1441 | 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 |
1442 | 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 |
1443 | 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 |
1444 | programs, though, as the fd could already be closed and reused for another |
1351 | thing, so beware. |
1445 | thing, so beware. |
1352 | .SS "\s-1GENERIC\s0 \s-1WATCHER\s0 \s-1FUNCTIONS\s0" |
1446 | .SS "\s-1GENERIC WATCHER FUNCTIONS\s0" |
1353 | .IX Subsection "GENERIC WATCHER FUNCTIONS" |
1447 | .IX Subsection "GENERIC WATCHER FUNCTIONS" |
1354 | .ie n .IP """ev_init"" (ev_TYPE *watcher, callback)" 4 |
1448 | .ie n .IP """ev_init"" (ev_TYPE *watcher, callback)" 4 |
1355 | .el .IP "\f(CWev_init\fR (ev_TYPE *watcher, callback)" 4 |
1449 | .el .IP "\f(CWev_init\fR (ev_TYPE *watcher, callback)" 4 |
1356 | .IX Item "ev_init (ev_TYPE *watcher, callback)" |
1450 | .IX Item "ev_init (ev_TYPE *watcher, callback)" |
1357 | This macro initialises the generic portion of a watcher. The contents |
1451 | 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 |
1530 | make sure the watcher is available to libev (e.g. you cannot \f(CW\*(C`free ()\*(C'\fR |
1437 | it). |
1531 | it). |
1438 | .IP "callback ev_cb (ev_TYPE *watcher)" 4 |
1532 | .IP "callback ev_cb (ev_TYPE *watcher)" 4 |
1439 | .IX Item "callback ev_cb (ev_TYPE *watcher)" |
1533 | .IX Item "callback ev_cb (ev_TYPE *watcher)" |
1440 | Returns the callback currently set on the watcher. |
1534 | Returns the callback currently set on the watcher. |
1441 | .IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 |
1535 | .IP "ev_set_cb (ev_TYPE *watcher, callback)" 4 |
1442 | .IX Item "ev_cb_set (ev_TYPE *watcher, callback)" |
1536 | .IX Item "ev_set_cb (ev_TYPE *watcher, callback)" |
1443 | Change the callback. You can change the callback at virtually any time |
1537 | Change the callback. You can change the callback at virtually any time |
1444 | (modulo threads). |
1538 | (modulo threads). |
1445 | .IP "ev_set_priority (ev_TYPE *watcher, int priority)" 4 |
1539 | .IP "ev_set_priority (ev_TYPE *watcher, int priority)" 4 |
1446 | .IX Item "ev_set_priority (ev_TYPE *watcher, int priority)" |
1540 | .IX Item "ev_set_priority (ev_TYPE *watcher, int priority)" |
1447 | .PD 0 |
1541 | .PD 0 |
… | |
… | |
1465 | or might not have been clamped to the valid range. |
1559 | or might not have been clamped to the valid range. |
1466 | .Sp |
1560 | .Sp |
1467 | The default priority used by watchers when no priority has been set is |
1561 | 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 :). |
1562 | always \f(CW0\fR, which is supposed to not be too high and not be too low :). |
1469 | .Sp |
1563 | .Sp |
1470 | See \*(L"\s-1WATCHER\s0 \s-1PRIORITY\s0 \s-1MODELS\s0\*(R", below, for a more thorough treatment of |
1564 | See \*(L"\s-1WATCHER PRIORITY MODELS\*(R"\s0, below, for a more thorough treatment of |
1471 | priorities. |
1565 | priorities. |
1472 | .IP "ev_invoke (loop, ev_TYPE *watcher, int revents)" 4 |
1566 | .IP "ev_invoke (loop, ev_TYPE *watcher, int revents)" 4 |
1473 | .IX Item "ev_invoke (loop, ev_TYPE *watcher, int revents)" |
1567 | .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 |
1568 | 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 |
1569 | \&\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. |
1589 | not started in the first place. |
1496 | .Sp |
1590 | .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 |
1591 | 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. |
1592 | functions that do not need a watcher. |
1499 | .PP |
1593 | .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 |
1594 | 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. |
1595 | OWN COMPOSITE WATCHERS\*(R"\s0 idioms. |
1502 | .SS "\s-1WATCHER\s0 \s-1STATES\s0" |
1596 | .SS "\s-1WATCHER STATES\s0" |
1503 | .IX Subsection "WATCHER STATES" |
1597 | .IX Subsection "WATCHER STATES" |
1504 | There are various watcher states mentioned throughout this manual \- |
1598 | There are various watcher states mentioned throughout this manual \- |
1505 | active, pending and so on. In this section these states and the rules to |
1599 | 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 |
1600 | 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". |
1601 | rules might look complicated, they usually do \*(L"the right thing\*(R". |
1508 | .IP "initialiased" 4 |
1602 | .IP "initialised" 4 |
1509 | .IX Item "initialiased" |
1603 | .IX Item "initialised" |
1510 | Before a watcher can be registered with the event loop it has to be |
1604 | 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 |
1605 | 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. |
1606 | \&\f(CW\*(C`ev_init\*(C'\fR followed by the watcher-specific \f(CW\*(C`ev_TYPE_set\*(C'\fR function. |
1513 | .Sp |
1607 | .Sp |
1514 | In this state it is simply some block of memory that is suitable for |
1608 | In this state it is simply some block of memory that is suitable for |
… | |
… | |
1550 | .Sp |
1644 | .Sp |
1551 | While stopped (and not pending) the watcher is essentially in the |
1645 | 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 |
1646 | 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 |
1647 | you wish (but when you trash the memory block, you need to \f(CW\*(C`ev_TYPE_init\*(C'\fR |
1554 | it again). |
1648 | it again). |
1555 | .SS "\s-1WATCHER\s0 \s-1PRIORITY\s0 \s-1MODELS\s0" |
1649 | .SS "\s-1WATCHER PRIORITY MODELS\s0" |
1556 | .IX Subsection "WATCHER PRIORITY MODELS" |
1650 | .IX Subsection "WATCHER PRIORITY MODELS" |
1557 | Many event loops support \fIwatcher priorities\fR, which are usually small |
1651 | Many event loops support \fIwatcher priorities\fR, which are usually small |
1558 | integers that influence the ordering of event callback invocation |
1652 | integers that influence the ordering of event callback invocation |
1559 | between watchers in some way, all else being equal. |
1653 | between watchers in some way, all else being equal. |
1560 | .PP |
1654 | .PP |
… | |
… | |
1705 | But really, best use non-blocking mode. |
1799 | But really, best use non-blocking mode. |
1706 | .PP |
1800 | .PP |
1707 | \fIThe special problem of disappearing file descriptors\fR |
1801 | \fIThe special problem of disappearing file descriptors\fR |
1708 | .IX Subsection "The special problem of disappearing file descriptors" |
1802 | .IX Subsection "The special problem of disappearing file descriptors" |
1709 | .PP |
1803 | .PP |
1710 | Some backends (e.g. kqueue, epoll) need to be told about closing a file |
1804 | 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, |
1805 | 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 |
1806 | 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 |
1807 | 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 |
1808 | 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 |
1809 | is registered with libev, there is no efficient way to see that this is, |
1716 | fact, a different file descriptor. |
1810 | in fact, a different file descriptor. |
1717 | .PP |
1811 | .PP |
1718 | To avoid having to explicitly tell libev about such cases, libev follows |
1812 | 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 |
1813 | 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 |
1814 | 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 |
1815 | 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. |
1852 | wish to read \- you would first have to request some data. |
1759 | .PP |
1853 | .PP |
1760 | Since files are typically not-so-well supported by advanced notification |
1854 | Since files are typically not-so-well supported by advanced notification |
1761 | mechanism, libev tries hard to emulate \s-1POSIX\s0 behaviour with respect |
1855 | 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 |
1856 | 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 |
1857 | 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 |
1858 | 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 |
1859 | (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 |
1860 | \&\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 |
1861 | asynchronous I/O instead of with non-blocking I/O, it is still useful when |
1768 | it \*(L"just works\*(R" instead of freezing. |
1862 | it \*(L"just works\*(R" instead of freezing. |
1769 | .PP |
1863 | .PP |
1770 | So avoid file descriptors pointing to files when you know it (e.g. use |
1864 | 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 |
1865 | 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 |
1866 | when you rarely read from a file instead of from a socket, and want to |
1773 | reuse the same code path. |
1867 | reuse the same code path. |
1774 | .PP |
1868 | .PP |
1775 | \fIThe special problem of fork\fR |
1869 | \fIThe special problem of fork\fR |
1776 | .IX Subsection "The special problem of fork" |
1870 | .IX Subsection "The special problem of fork" |
1777 | .PP |
1871 | .PP |
1778 | Some backends (epoll, kqueue) do not support \f(CW\*(C`fork ()\*(C'\fR at all or exhibit |
1872 | 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 |
1873 | 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. |
1874 | to be told about it in the child if you want to continue to use it in the |
|
|
1875 | child. |
1781 | .PP |
1876 | .PP |
1782 | To support fork in your child processes, you have to call \f(CW\*(C`ev_loop_fork |
1877 | 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 |
1878 | ()\*(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. |
1879 | \&\f(CW\*(C`EVBACKEND_SELECT\*(C'\fR or \f(CW\*(C`EVBACKEND_POLL\*(C'\fR. |
1785 | .PP |
1880 | .PP |
1786 | \fIThe special problem of \s-1SIGPIPE\s0\fR |
1881 | \fIThe special problem of \s-1SIGPIPE\s0\fR |
1787 | .IX Subsection "The special problem of SIGPIPE" |
1882 | .IX Subsection "The special problem of SIGPIPE" |
1788 | .PP |
1883 | .PP |
1789 | While not really specific to libev, it is easy to forget about \f(CW\*(C`SIGPIPE\*(C'\fR: |
1884 | 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 |
1885 | 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 |
1886 | 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. |
1887 | this is sensible behaviour, for daemons, this is usually undesirable. |
1793 | .PP |
1888 | .PP |
1794 | So when you encounter spurious, unexplained daemon exits, make sure you |
1889 | 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 |
1890 | 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). |
1891 | somewhere, as that would have given you a big clue). |
1797 | .PP |
1892 | .PP |
1798 | \fIThe special problem of \fIaccept()\fIing when you can't\fR |
1893 | \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" |
1894 | .IX Subsection "The special problem of accept()ing when you can't" |
1800 | .PP |
1895 | .PP |
1801 | Many implementations of the \s-1POSIX\s0 \f(CW\*(C`accept\*(C'\fR function (for example, |
1896 | 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 |
1897 | found in post\-2004 Linux) have the peculiar behaviour of not removing a |
1803 | connection from the pending queue in all error cases. |
1898 | connection from the pending queue in all error cases. |
… | |
… | |
1994 | \& callback (EV_P_ ev_timer *w, int revents) |
2089 | \& callback (EV_P_ ev_timer *w, int revents) |
1995 | \& { |
2090 | \& { |
1996 | \& // calculate when the timeout would happen |
2091 | \& // calculate when the timeout would happen |
1997 | \& ev_tstamp after = last_activity \- ev_now (EV_A) + timeout; |
2092 | \& ev_tstamp after = last_activity \- ev_now (EV_A) + timeout; |
1998 | \& |
2093 | \& |
1999 | \& // if negative, it means we the timeout already occured |
2094 | \& // if negative, it means we the timeout already occurred |
2000 | \& if (after < 0.) |
2095 | \& if (after < 0.) |
2001 | \& { |
2096 | \& { |
2002 | \& // timeout occurred, take action |
2097 | \& // timeout occurred, take action |
2003 | \& } |
2098 | \& } |
2004 | \& else |
2099 | \& else |
… | |
… | |
2023 | .Sp |
2118 | .Sp |
2024 | Otherwise, we now the earliest time at which the timeout would trigger, |
2119 | Otherwise, we now the earliest time at which the timeout would trigger, |
2025 | and simply start the timer with this timeout value. |
2120 | and simply start the timer with this timeout value. |
2026 | .Sp |
2121 | .Sp |
2027 | In other words, each time the callback is invoked it will check whether |
2122 | 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 |
2123 | the timeout occurred. If not, it will simply reschedule itself to check |
2029 | again at the earliest time it could time out. Rinse. Repeat. |
2124 | again at the earliest time it could time out. Rinse. Repeat. |
2030 | .Sp |
2125 | .Sp |
2031 | This scheme causes more callback invocations (about one every 60 seconds |
2126 | This scheme causes more callback invocations (about one every 60 seconds |
2032 | minus half the average time between activity), but virtually no calls to |
2127 | minus half the average time between activity), but virtually no calls to |
2033 | libev to change the timeout. |
2128 | libev to change the timeout. |
… | |
… | |
2051 | \& last_activity = ev_now (EV_A); |
2146 | \& last_activity = ev_now (EV_A); |
2052 | .Ve |
2147 | .Ve |
2053 | .Sp |
2148 | .Sp |
2054 | When your timeout value changes, then the timeout can be changed by simply |
2149 | 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 |
2150 | providing a new value, stopping the timer and calling the callback, which |
2056 | will agaion do the right thing (for example, time out immediately :). |
2151 | will again do the right thing (for example, time out immediately :). |
2057 | .Sp |
2152 | .Sp |
2058 | .Vb 3 |
2153 | .Vb 3 |
2059 | \& timeout = new_value; |
2154 | \& timeout = new_value; |
2060 | \& ev_timer_stop (EV_A_ &timer); |
2155 | \& ev_timer_stop (EV_A_ &timer); |
2061 | \& callback (EV_A_ &timer, 0); |
2156 | \& callback (EV_A_ &timer, 0); |
… | |
… | |
2145 | .PP |
2240 | .PP |
2146 | The relative timeouts are calculated relative to the \f(CW\*(C`ev_now ()\*(C'\fR |
2241 | 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 |
2242 | 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 |
2243 | 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 |
2244 | 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: |
2245 | timeout on the current time, use something like the following to adjust |
|
|
2246 | for it: |
2151 | .PP |
2247 | .PP |
2152 | .Vb 1 |
2248 | .Vb 1 |
2153 | \& ev_timer_set (&timer, after + ev_now () \- ev_time (), 0.); |
2249 | \& ev_timer_set (&timer, after + (ev_time () \- ev_now ()), 0.); |
2154 | .Ve |
2250 | .Ve |
2155 | .PP |
2251 | .PP |
2156 | If the event loop is suspended for a long time, you can also force an |
2252 | 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 |
2253 | update of the time returned by \f(CW\*(C`ev_now ()\*(C'\fR by calling \f(CW\*(C`ev_now_update |
2158 | ()\*(C'\fR. |
2254 | ()\*(C'\fR, although that will push the event time of all outstanding events |
|
|
2255 | further into the future. |
2159 | .PP |
2256 | .PP |
2160 | \fIThe special problem of unsynchronised clocks\fR |
2257 | \fIThe special problem of unsynchronised clocks\fR |
2161 | .IX Subsection "The special problem of unsynchronised clocks" |
2258 | .IX Subsection "The special problem of unsynchronised clocks" |
2162 | .PP |
2259 | .PP |
2163 | Modern systems have a variety of clocks \- libev itself uses the normal |
2260 | 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)" |
2325 | .IX Item "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" |
2229 | .PD 0 |
2326 | .PD 0 |
2230 | .IP "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)" 4 |
2327 | .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)" |
2328 | .IX Item "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)" |
2232 | .PD |
2329 | .PD |
2233 | Configure the timer to trigger after \f(CW\*(C`after\*(C'\fR seconds. If \f(CW\*(C`repeat\*(C'\fR |
2330 | 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 |
2331 | 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 |
2332 | 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, |
2333 | then the timer will automatically be configured to trigger again \f(CW\*(C`repeat\*(C'\fR |
2237 | until stopped manually. |
2334 | seconds later, again, and again, until stopped manually. |
2238 | .Sp |
2335 | .Sp |
2239 | The timer itself will do a best-effort at avoiding drift, that is, if |
2336 | 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 |
2337 | 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 |
2338 | 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 |
2339 | 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 |
2421 | Periodic watchers are also timers of a kind, but they are very versatile |
2325 | (and unfortunately a bit complex). |
2422 | (and unfortunately a bit complex). |
2326 | .PP |
2423 | .PP |
2327 | Unlike \f(CW\*(C`ev_timer\*(C'\fR, periodic watchers are not based on real time (or |
2424 | 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 |
2425 | 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 |
2426 | (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 |
2427 | 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 |
2428 | time, and time jumps are not uncommon (e.g. when you adjust your |
2332 | wrist-watch). |
2429 | wrist-watch). |
2333 | .PP |
2430 | .PP |
2334 | You can tell a periodic watcher to trigger after some specific point |
2431 | 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 |
2436 | \&\f(CW\*(C`ev_timer\*(C'\fR, which would still trigger roughly 10 seconds after starting |
2340 | it, as it uses a relative timeout). |
2437 | it, as it uses a relative timeout). |
2341 | .PP |
2438 | .PP |
2342 | \&\f(CW\*(C`ev_periodic\*(C'\fR watchers can also be used to implement vastly more complex |
2439 | \&\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 |
2440 | 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 |
2441 | other complicated rules. This cannot easily be done with \f(CW\*(C`ev_timer\*(C'\fR |
2345 | those cannot react to time jumps. |
2442 | watchers, as those cannot react to time jumps. |
2346 | .PP |
2443 | .PP |
2347 | As with timers, the callback is guaranteed to be invoked only when the |
2444 | 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 |
2445 | 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 |
2446 | 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 |
2447 | 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 |
2508 | 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 |
2509 | ignored. Instead, each time the periodic watcher gets scheduled, the |
2413 | reschedule callback will be called with the watcher as first, and the |
2510 | reschedule callback will be called with the watcher as first, and the |
2414 | current time as second argument. |
2511 | current time as second argument. |
2415 | .Sp |
2512 | .Sp |
2416 | \&\s-1NOTE:\s0 \fIThis callback \s-1MUST\s0 \s-1NOT\s0 stop or destroy any periodic watcher, ever, |
2513 | \&\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 |
2514 | or make \s-1ANY\s0 other event loop modifications whatsoever, unless explicitly |
2418 | allowed by documentation here\fR. |
2515 | allowed by documentation here\fR. |
2419 | .Sp |
2516 | .Sp |
2420 | If you need to stop it, return \f(CW\*(C`now + 1e30\*(C'\fR (or so, fudge fudge) and stop |
2517 | 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 |
2518 | it afterwards (e.g. by starting an \f(CW\*(C`ev_prepare\*(C'\fR watcher, which is the |
… | |
… | |
2439 | .Sp |
2536 | .Sp |
2440 | \&\s-1NOTE:\s0 \fIThis callback must always return a time that is higher than or |
2537 | \&\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. |
2538 | equal to the passed \f(CI\*(C`now\*(C'\fI value\fR. |
2442 | .Sp |
2539 | .Sp |
2443 | This can be used to create very complex timers, such as a timer that |
2540 | 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 |
2541 | 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 |
2542 | 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 |
2543 | this. Here is a (completely untested, no error checking) example on how to |
2447 | reason I omitted it as an example). |
2544 | do this: |
|
|
2545 | .Sp |
|
|
2546 | .Vb 1 |
|
|
2547 | \& #include <time.h> |
|
|
2548 | \& |
|
|
2549 | \& static ev_tstamp |
|
|
2550 | \& my_rescheduler (ev_periodic *w, ev_tstamp now) |
|
|
2551 | \& { |
|
|
2552 | \& time_t tnow = (time_t)now; |
|
|
2553 | \& struct tm tm; |
|
|
2554 | \& localtime_r (&tnow, &tm); |
|
|
2555 | \& |
|
|
2556 | \& tm.tm_sec = tm.tm_min = tm.tm_hour = 0; // midnight current day |
|
|
2557 | \& ++tm.tm_mday; // midnight next day |
|
|
2558 | \& |
|
|
2559 | \& return mktime (&tm); |
|
|
2560 | \& } |
|
|
2561 | .Ve |
|
|
2562 | .Sp |
|
|
2563 | Note: this code might run into trouble on days that have more then two |
|
|
2564 | midnights (beginning and end). |
2448 | .RE |
2565 | .RE |
2449 | .RS 4 |
2566 | .RS 4 |
2450 | .RE |
2567 | .RE |
2451 | .IP "ev_periodic_again (loop, ev_periodic *)" 4 |
2568 | .IP "ev_periodic_again (loop, ev_periodic *)" 4 |
2452 | .IX Item "ev_periodic_again (loop, ev_periodic *)" |
2569 | .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 |
2654 | 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 |
2655 | 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 |
2656 | \&\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. |
2657 | the moment, \f(CW\*(C`SIGCHLD\*(C'\fR is permanently tied to the default loop. |
2541 | .PP |
2658 | .PP |
2542 | When the first watcher gets started will libev actually register something |
2659 | 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 |
2660 | register something with the kernel. It thus coexists with your own signal |
2544 | you don't register any with libev for the same signal). |
2661 | handlers as long as you don't register any with libev for the same signal. |
2545 | .PP |
2662 | .PP |
2546 | If possible and supported, libev will install its handlers with |
2663 | 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 |
2664 | \&\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 |
2665 | 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 |
2666 | 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. |
2727 | The signal the watcher watches out for. |
2611 | .PP |
2728 | .PP |
2612 | \fIExamples\fR |
2729 | \fIExamples\fR |
2613 | .IX Subsection "Examples" |
2730 | .IX Subsection "Examples" |
2614 | .PP |
2731 | .PP |
2615 | Example: Try to exit cleanly on \s-1SIGINT\s0. |
2732 | Example: Try to exit cleanly on \s-1SIGINT.\s0 |
2616 | .PP |
2733 | .PP |
2617 | .Vb 5 |
2734 | .Vb 5 |
2618 | \& static void |
2735 | \& static void |
2619 | \& sigint_cb (struct ev_loop *loop, ev_signal *w, int revents) |
2736 | \& sigint_cb (struct ev_loop *loop, ev_signal *w, int revents) |
2620 | \& { |
2737 | \& { |
… | |
… | |
2735 | .ie n .SS """ev_stat"" \- did the file attributes just change?" |
2852 | .ie n .SS """ev_stat"" \- did the file attributes just change?" |
2736 | .el .SS "\f(CWev_stat\fP \- did the file attributes just change?" |
2853 | .el .SS "\f(CWev_stat\fP \- did the file attributes just change?" |
2737 | .IX Subsection "ev_stat - did the file attributes just change?" |
2854 | .IX Subsection "ev_stat - did the file attributes just change?" |
2738 | This watches a file system path for attribute changes. That is, it calls |
2855 | 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) |
2856 | \&\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 |
2857 | and sees if it changed compared to the last time, invoking the callback |
2741 | it did. |
2858 | if it did. Starting the watcher \f(CW\*(C`stat\*(C'\fR's the file, so only changes that |
|
|
2859 | happen after the watcher has been started will be reported. |
2742 | .PP |
2860 | .PP |
2743 | The path does not need to exist: changing from \*(L"path exists\*(R" to \*(L"path does |
2861 | 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 |
2862 | 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 |
2863 | 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 |
2864 | \&\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 |
2894 | compilation environment, which means that on systems with large file |
2777 | support disabled by default, you get the 32 bit version of the stat |
2895 | 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 |
2896 | 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 |
2897 | 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 |
2898 | 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 |
2899 | 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. |
2900 | most noticeably displayed with ev_stat and large file support. |
2783 | .PP |
2901 | .PP |
2784 | The solution for this is to lobby your distribution maker to make large |
2902 | 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 |
2903 | 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 |
2904 | optional. Libev cannot simply switch on large file support because it has |
… | |
… | |
2977 | Apart from keeping your process non-blocking (which is a useful |
3095 | 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 |
3096 | 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 |
3097 | \&\*(L"pseudo-background processing\*(R", or delay processing stuff to after the |
2980 | event loop has handled all outstanding events. |
3098 | event loop has handled all outstanding events. |
2981 | .PP |
3099 | .PP |
|
|
3100 | \fIAbusing an \f(CI\*(C`ev_idle\*(C'\fI watcher for its side-effect\fR |
|
|
3101 | .IX Subsection "Abusing an ev_idle watcher for its side-effect" |
|
|
3102 | .PP |
|
|
3103 | As long as there is at least one active idle watcher, libev will never |
|
|
3104 | sleep unnecessarily. Or in other words, it will loop as fast as possible. |
|
|
3105 | For this to work, the idle watcher doesn't need to be invoked at all \- the |
|
|
3106 | lowest priority will do. |
|
|
3107 | .PP |
|
|
3108 | This mode of operation can be useful together with an \f(CW\*(C`ev_check\*(C'\fR watcher, |
|
|
3109 | to do something on each event loop iteration \- for example to balance load |
|
|
3110 | between different connections. |
|
|
3111 | .PP |
|
|
3112 | See \*(L"Abusing an ev_check watcher for its side-effect\*(R" for a longer |
|
|
3113 | example. |
|
|
3114 | .PP |
2982 | \fIWatcher-Specific Functions and Data Members\fR |
3115 | \fIWatcher-Specific Functions and Data Members\fR |
2983 | .IX Subsection "Watcher-Specific Functions and Data Members" |
3116 | .IX Subsection "Watcher-Specific Functions and Data Members" |
2984 | .IP "ev_idle_init (ev_idle *, callback)" 4 |
3117 | .IP "ev_idle_init (ev_idle *, callback)" 4 |
2985 | .IX Item "ev_idle_init (ev_idle *, callback)" |
3118 | .IX Item "ev_idle_init (ev_idle *, callback)" |
2986 | Initialises and configures the idle watcher \- it has no parameters of any |
3119 | Initialises and configures the idle watcher \- it has no parameters of any |
… | |
… | |
2991 | .IX Subsection "Examples" |
3124 | .IX Subsection "Examples" |
2992 | .PP |
3125 | .PP |
2993 | Example: Dynamically allocate an \f(CW\*(C`ev_idle\*(C'\fR watcher, start it, and in the |
3126 | 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. |
3127 | callback, free it. Also, use no error checking, as usual. |
2995 | .PP |
3128 | .PP |
2996 | .Vb 7 |
3129 | .Vb 5 |
2997 | \& static void |
3130 | \& static void |
2998 | \& idle_cb (struct ev_loop *loop, ev_idle *w, int revents) |
3131 | \& idle_cb (struct ev_loop *loop, ev_idle *w, int revents) |
2999 | \& { |
3132 | \& { |
|
|
3133 | \& // stop the watcher |
|
|
3134 | \& ev_idle_stop (loop, w); |
|
|
3135 | \& |
|
|
3136 | \& // now we can free it |
3000 | \& free (w); |
3137 | \& free (w); |
|
|
3138 | \& |
3001 | \& // now do something you wanted to do when the program has |
3139 | \& // now do something you wanted to do when the program has |
3002 | \& // no longer anything immediate to do. |
3140 | \& // no longer anything immediate to do. |
3003 | \& } |
3141 | \& } |
3004 | \& |
3142 | \& |
3005 | \& ev_idle *idle_watcher = malloc (sizeof (ev_idle)); |
3143 | \& ev_idle *idle_watcher = malloc (sizeof (ev_idle)); |
… | |
… | |
3007 | \& ev_idle_start (loop, idle_watcher); |
3145 | \& ev_idle_start (loop, idle_watcher); |
3008 | .Ve |
3146 | .Ve |
3009 | .ie n .SS """ev_prepare"" and ""ev_check"" \- customise your event loop!" |
3147 | .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!" |
3148 | .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!" |
3149 | .IX Subsection "ev_prepare and ev_check - customise your event loop!" |
3012 | Prepare and check watchers are usually (but not always) used in pairs: |
3150 | Prepare and check watchers are often (but not always) used in pairs: |
3013 | prepare watchers get invoked before the process blocks and check watchers |
3151 | prepare watchers get invoked before the process blocks and check watchers |
3014 | afterwards. |
3152 | afterwards. |
3015 | .PP |
3153 | .PP |
3016 | You \fImust not\fR call \f(CW\*(C`ev_run\*(C'\fR or similar functions that enter |
3154 | 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 |
3155 | 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 |
3156 | \&\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 |
3157 | 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, |
3158 | 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 |
3159 | \&\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. |
3160 | kind they will always be called in pairs bracketing the blocking call. |
3023 | .PP |
3161 | .PP |
3024 | Their main purpose is to integrate other event mechanisms into libev and |
3162 | 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 |
3163 | 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 |
3164 | variable changes, implement your own watchers, integrate net-snmp or a |
3027 | coroutine library and lots more. They are also occasionally useful if |
3165 | 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 |
3183 | 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 |
3184 | 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 |
3185 | loop from blocking if lower-priority coroutines are active, thus mapping |
3048 | low-priority coroutines to idle/background tasks). |
3186 | low-priority coroutines to idle/background tasks). |
3049 | .PP |
3187 | .PP |
3050 | It is recommended to give \f(CW\*(C`ev_check\*(C'\fR watchers highest (\f(CW\*(C`EV_MAXPRI\*(C'\fR) |
3188 | 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 |
3189 | 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). |
3190 | any other watchers after the poll (this doesn't matter for \f(CW\*(C`ev_prepare\*(C'\fR |
|
|
3191 | watchers). |
3053 | .PP |
3192 | .PP |
3054 | Also, \f(CW\*(C`ev_check\*(C'\fR watchers (and \f(CW\*(C`ev_prepare\*(C'\fR watchers, too) should not |
3193 | 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 |
3194 | 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 |
3195 | 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 |
3196 | \&\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 |
3197 | 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 |
3198 | \&\f(CW\*(C`ev_check\*(C'\fR watcher ran (always remind yourself to coexist peacefully with |
3060 | others). |
3199 | others). |
|
|
3200 | .PP |
|
|
3201 | \fIAbusing an \f(CI\*(C`ev_check\*(C'\fI watcher for its side-effect\fR |
|
|
3202 | .IX Subsection "Abusing an ev_check watcher for its side-effect" |
|
|
3203 | .PP |
|
|
3204 | \&\f(CW\*(C`ev_check\*(C'\fR (and less often also \f(CW\*(C`ev_prepare\*(C'\fR) watchers can also be |
|
|
3205 | useful because they are called once per event loop iteration. For |
|
|
3206 | example, if you want to handle a large number of connections fairly, you |
|
|
3207 | normally only do a bit of work for each active connection, and if there |
|
|
3208 | is more work to do, you wait for the next event loop iteration, so other |
|
|
3209 | connections have a chance of making progress. |
|
|
3210 | .PP |
|
|
3211 | Using an \f(CW\*(C`ev_check\*(C'\fR watcher is almost enough: it will be called on the |
|
|
3212 | next event loop iteration. However, that isn't as soon as possible \- |
|
|
3213 | without external events, your \f(CW\*(C`ev_check\*(C'\fR watcher will not be invoked. |
|
|
3214 | .PP |
|
|
3215 | This is where \f(CW\*(C`ev_idle\*(C'\fR watchers come in handy \- all you need is a |
|
|
3216 | single global idle watcher that is active as long as you have one active |
|
|
3217 | \&\f(CW\*(C`ev_check\*(C'\fR watcher. The \f(CW\*(C`ev_idle\*(C'\fR watcher makes sure the event loop |
|
|
3218 | will not sleep, and the \f(CW\*(C`ev_check\*(C'\fR watcher makes sure a callback gets |
|
|
3219 | invoked. Neither watcher alone can do that. |
3061 | .PP |
3220 | .PP |
3062 | \fIWatcher-Specific Functions and Data Members\fR |
3221 | \fIWatcher-Specific Functions and Data Members\fR |
3063 | .IX Subsection "Watcher-Specific Functions and Data Members" |
3222 | .IX Subsection "Watcher-Specific Functions and Data Members" |
3064 | .IP "ev_prepare_init (ev_prepare *, callback)" 4 |
3223 | .IP "ev_prepare_init (ev_prepare *, callback)" 4 |
3065 | .IX Item "ev_prepare_init (ev_prepare *, callback)" |
3224 | .IX Item "ev_prepare_init (ev_prepare *, callback)" |
… | |
… | |
3176 | .Ve |
3335 | .Ve |
3177 | .PP |
3336 | .PP |
3178 | Method 4: Do not use a prepare or check watcher because the module you |
3337 | 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 |
3338 | 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 |
3339 | 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 |
3340 | 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 |
3341 | this approach, effectively embedding \s-1EV\s0 as a client into the horrible |
3183 | libglib event loop. |
3342 | libglib event loop. |
3184 | .PP |
3343 | .PP |
3185 | .Vb 4 |
3344 | .Vb 4 |
3186 | \& static gint |
3345 | \& static gint |
… | |
… | |
3270 | \fIWatcher-Specific Functions and Data Members\fR |
3429 | \fIWatcher-Specific Functions and Data Members\fR |
3271 | .IX Subsection "Watcher-Specific Functions and Data Members" |
3430 | .IX Subsection "Watcher-Specific Functions and Data Members" |
3272 | .IP "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
3431 | .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)" |
3432 | .IX Item "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" |
3274 | .PD 0 |
3433 | .PD 0 |
3275 | .IP "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 |
3434 | .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)" |
3435 | .IX Item "ev_embed_set (ev_embed *, struct ev_loop *embedded_loop)" |
3277 | .PD |
3436 | .PD |
3278 | Configures the watcher to embed the given loop, which must be |
3437 | 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 |
3438 | 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 |
3439 | 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, |
3440 | to invoke it (it will continue to be called until the sweep has been done, |
… | |
… | |
3300 | .PP |
3459 | .PP |
3301 | .Vb 3 |
3460 | .Vb 3 |
3302 | \& struct ev_loop *loop_hi = ev_default_init (0); |
3461 | \& struct ev_loop *loop_hi = ev_default_init (0); |
3303 | \& struct ev_loop *loop_lo = 0; |
3462 | \& struct ev_loop *loop_lo = 0; |
3304 | \& ev_embed embed; |
3463 | \& ev_embed embed; |
3305 | \& |
3464 | \& |
3306 | \& // see if there is a chance of getting one that works |
3465 | \& // see if there is a chance of getting one that works |
3307 | \& // (remember that a flags value of 0 means autodetection) |
3466 | \& // (remember that a flags value of 0 means autodetection) |
3308 | \& loop_lo = ev_embeddable_backends () & ev_recommended_backends () |
3467 | \& loop_lo = ev_embeddable_backends () & ev_recommended_backends () |
3309 | \& ? ev_loop_new (ev_embeddable_backends () & ev_recommended_backends ()) |
3468 | \& ? ev_loop_new (ev_embeddable_backends () & ev_recommended_backends ()) |
3310 | \& : 0; |
3469 | \& : 0; |
… | |
… | |
3326 | .PP |
3485 | .PP |
3327 | .Vb 3 |
3486 | .Vb 3 |
3328 | \& struct ev_loop *loop = ev_default_init (0); |
3487 | \& struct ev_loop *loop = ev_default_init (0); |
3329 | \& struct ev_loop *loop_socket = 0; |
3488 | \& struct ev_loop *loop_socket = 0; |
3330 | \& ev_embed embed; |
3489 | \& ev_embed embed; |
3331 | \& |
3490 | \& |
3332 | \& if (ev_supported_backends () & ~ev_recommended_backends () & EVBACKEND_KQUEUE) |
3491 | \& if (ev_supported_backends () & ~ev_recommended_backends () & EVBACKEND_KQUEUE) |
3333 | \& if ((loop_socket = ev_loop_new (EVBACKEND_KQUEUE)) |
3492 | \& if ((loop_socket = ev_loop_new (EVBACKEND_KQUEUE)) |
3334 | \& { |
3493 | \& { |
3335 | \& ev_embed_init (&embed, 0, loop_socket); |
3494 | \& ev_embed_init (&embed, 0, loop_socket); |
3336 | \& ev_embed_start (loop, &embed); |
3495 | \& ev_embed_start (loop, &embed); |
… | |
… | |
3344 | .ie n .SS """ev_fork"" \- the audacity to resume the event loop after a fork" |
3503 | .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" |
3504 | .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" |
3505 | .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 |
3506 | 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 |
3507 | 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 |
3508 | \&\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, |
3509 | 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 |
3510 | 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 |
3511 | and calls it in the wrong process, the fork handlers will be invoked, too, |
3353 | handlers will be invoked, too, of course. |
3512 | of course. |
3354 | .PP |
3513 | .PP |
3355 | \fIThe special problem of life after fork \- how is it possible?\fR |
3514 | \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?" |
3515 | .IX Subsection "The special problem of life after fork - how is it possible?" |
3357 | .PP |
3516 | .PP |
3358 | Most uses of \f(CW\*(C`fork()\*(C'\fR consist of forking, then some simple calls to set |
3517 | 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 |
3518 | 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. |
3519 | sequence should be handled by libev without any problems. |
3361 | .PP |
3520 | .PP |
3362 | This changes when the application actually wants to do event handling |
3521 | 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 |
3522 | 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. |
3603 | it by calling \f(CW\*(C`ev_async_send\*(C'\fR, which is thread\- and signal safe. |
3445 | .PP |
3604 | .PP |
3446 | This functionality is very similar to \f(CW\*(C`ev_signal\*(C'\fR watchers, as signals, |
3605 | 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 |
3606 | 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 |
3607 | (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 |
3608 | \&\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 |
3609 | 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, |
3610 | 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. |
3611 | even without knowing which loop owns the signal. |
3453 | .PP |
3612 | .PP |
3454 | \fIQueueing\fR |
3613 | \fIQueueing\fR |
… | |
… | |
3580 | is a time window between the event loop checking and resetting the async |
3739 | is a time window between the event loop checking and resetting the async |
3581 | notification, and the callback being invoked. |
3740 | notification, and the callback being invoked. |
3582 | .SH "OTHER FUNCTIONS" |
3741 | .SH "OTHER FUNCTIONS" |
3583 | .IX Header "OTHER FUNCTIONS" |
3742 | .IX Header "OTHER FUNCTIONS" |
3584 | There are some other functions of possible interest. Described. Here. Now. |
3743 | 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 |
3744 | .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)" |
3745 | .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 |
3746 | This function combines a simple timer and an I/O watcher, calls your |
3588 | callback on whichever event happens first and automatically stops both |
3747 | 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 |
3748 | 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 |
3749 | or timeout without having to allocate/configure/start/stop/free one or |
3591 | more watchers yourself. |
3750 | 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 |
3762 | \&\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 |
3763 | 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 |
3764 | a timeout and an io event at the same time \- you probably should give io |
3606 | events precedence. |
3765 | events precedence. |
3607 | .Sp |
3766 | .Sp |
3608 | Example: wait up to ten seconds for data to appear on \s-1STDIN_FILENO\s0. |
3767 | Example: wait up to ten seconds for data to appear on \s-1STDIN_FILENO.\s0 |
3609 | .Sp |
3768 | .Sp |
3610 | .Vb 7 |
3769 | .Vb 7 |
3611 | \& static void stdin_ready (int revents, void *arg) |
3770 | \& static void stdin_ready (int revents, void *arg) |
3612 | \& { |
3771 | \& { |
3613 | \& if (revents & EV_READ) |
3772 | \& if (revents & EV_READ) |
… | |
… | |
3629 | .SH "COMMON OR USEFUL IDIOMS (OR BOTH)" |
3788 | .SH "COMMON OR USEFUL IDIOMS (OR BOTH)" |
3630 | .IX Header "COMMON OR USEFUL IDIOMS (OR BOTH)" |
3789 | .IX Header "COMMON OR USEFUL IDIOMS (OR BOTH)" |
3631 | This section explains some common idioms that are not immediately |
3790 | This section explains some common idioms that are not immediately |
3632 | obvious. Note that examples are sprinkled over the whole manual, and this |
3791 | obvious. Note that examples are sprinkled over the whole manual, and this |
3633 | section only contains stuff that wouldn't fit anywhere else. |
3792 | 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" |
3793 | .SS "\s-1ASSOCIATING CUSTOM DATA WITH A WATCHER\s0" |
3635 | .IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER" |
3794 | .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 |
3795 | 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 |
3796 | 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 |
3797 | 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 |
3798 | don't want to allocate memory separately and store a pointer to it in that |
… | |
… | |
3665 | \& } |
3824 | \& } |
3666 | .Ve |
3825 | .Ve |
3667 | .PP |
3826 | .PP |
3668 | More interesting and less C\-conformant ways of casting your callback |
3827 | More interesting and less C\-conformant ways of casting your callback |
3669 | function type instead have been omitted. |
3828 | function type instead have been omitted. |
3670 | .SS "\s-1BUILDING\s0 \s-1YOUR\s0 \s-1OWN\s0 \s-1COMPOSITE\s0 \s-1WATCHERS\s0" |
3829 | .SS "\s-1BUILDING YOUR OWN COMPOSITE WATCHERS\s0" |
3671 | .IX Subsection "BUILDING YOUR OWN COMPOSITE WATCHERS" |
3830 | .IX Subsection "BUILDING YOUR OWN COMPOSITE WATCHERS" |
3672 | Another common scenario is to use some data structure with multiple |
3831 | Another common scenario is to use some data structure with multiple |
3673 | embedded watchers, in effect creating your own watcher that combines |
3832 | embedded watchers, in effect creating your own watcher that combines |
3674 | multiple libev event sources into one \*(L"super-watcher\*(R": |
3833 | multiple libev event sources into one \*(L"super-watcher\*(R": |
3675 | .PP |
3834 | .PP |
… | |
… | |
3703 | \& { |
3862 | \& { |
3704 | \& struct my_biggy big = (struct my_biggy *) |
3863 | \& struct my_biggy big = (struct my_biggy *) |
3705 | \& (((char *)w) \- offsetof (struct my_biggy, t2)); |
3864 | \& (((char *)w) \- offsetof (struct my_biggy, t2)); |
3706 | \& } |
3865 | \& } |
3707 | .Ve |
3866 | .Ve |
3708 | .SS "\s-1AVOIDING\s0 \s-1FINISHING\s0 \s-1BEFORE\s0 \s-1RETURNING\s0" |
3867 | .SS "\s-1AVOIDING FINISHING BEFORE RETURNING\s0" |
3709 | .IX Subsection "AVOIDING FINISHING BEFORE RETURNING" |
3868 | .IX Subsection "AVOIDING FINISHING BEFORE RETURNING" |
3710 | Often you have structures like this in event-based programs: |
3869 | Often you have structures like this in event-based programs: |
3711 | .PP |
3870 | .PP |
3712 | .Vb 4 |
3871 | .Vb 4 |
3713 | \& callback () |
3872 | \& callback () |
… | |
… | |
3735 | already been invoked. |
3894 | already been invoked. |
3736 | .PP |
3895 | .PP |
3737 | A common way around all these issues is to make sure that |
3896 | 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 |
3897 | \&\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 |
3898 | \&\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 |
3899 | 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 |
3900 | example, or more sneakily, by reusing an existing (stopped) watcher and |
3742 | and pushing it into the pending queue: |
3901 | pushing it into the pending queue: |
3743 | .PP |
3902 | .PP |
3744 | .Vb 2 |
3903 | .Vb 2 |
3745 | \& ev_set_cb (watcher, callback); |
3904 | \& ev_set_cb (watcher, callback); |
3746 | \& ev_feed_event (EV_A_ watcher, 0); |
3905 | \& ev_feed_event (EV_A_ watcher, 0); |
3747 | .Ve |
3906 | .Ve |
3748 | .PP |
3907 | .PP |
3749 | This way, \f(CW\*(C`start_new_request\*(C'\fR can safely return before the callback is |
3908 | 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. |
3909 | 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" |
3910 | .SS "\s-1MODEL/NESTED EVENT LOOP INVOCATIONS AND EXIT CONDITIONS\s0" |
3752 | .IX Subsection "MODEL/NESTED EVENT LOOP INVOCATIONS AND EXIT CONDITIONS" |
3911 | .IX Subsection "MODEL/NESTED EVENT LOOP INVOCATIONS AND EXIT CONDITIONS" |
3753 | Often (especially in \s-1GUI\s0 toolkits) there are places where you have |
3912 | Often (especially in \s-1GUI\s0 toolkits) there are places where you have |
3754 | \&\fImodal\fR interaction, which is most easily implemented by recursively |
3913 | \&\fImodal\fR interaction, which is most easily implemented by recursively |
3755 | invoking \f(CW\*(C`ev_run\*(C'\fR. |
3914 | invoking \f(CW\*(C`ev_run\*(C'\fR. |
3756 | .PP |
3915 | .PP |
3757 | This brings the problem of exiting \- a callback might want to finish the |
3916 | 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 |
3917 | 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 |
3918 | 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 |
3919 | 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. |
3920 | other combination: In these cases, a simple \f(CW\*(C`ev_break\*(C'\fR will not work. |
3762 | .PP |
3921 | .PP |
3763 | The solution is to maintain \*(L"break this loop\*(R" variable for each \f(CW\*(C`ev_run\*(C'\fR |
3922 | 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 |
3923 | 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: |
3924 | triggered, using \f(CW\*(C`EVRUN_ONCE\*(C'\fR: |
3766 | .PP |
3925 | .PP |
… | |
… | |
3788 | \& exit_main_loop = 1; |
3947 | \& exit_main_loop = 1; |
3789 | \& |
3948 | \& |
3790 | \& // exit both |
3949 | \& // exit both |
3791 | \& exit_main_loop = exit_nested_loop = 1; |
3950 | \& exit_main_loop = exit_nested_loop = 1; |
3792 | .Ve |
3951 | .Ve |
3793 | .SS "\s-1THREAD\s0 \s-1LOCKING\s0 \s-1EXAMPLE\s0" |
3952 | .SS "\s-1THREAD LOCKING EXAMPLE\s0" |
3794 | .IX Subsection "THREAD LOCKING EXAMPLE" |
3953 | .IX Subsection "THREAD LOCKING EXAMPLE" |
3795 | Here is a fictitious example of how to run an event loop in a different |
3954 | 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 |
3955 | thread from where callbacks are being invoked and watchers are |
3797 | created/added/removed. |
3956 | created/added/removed. |
3798 | .PP |
3957 | .PP |
… | |
… | |
3939 | .PP |
4098 | .PP |
3940 | Note that sending the \f(CW\*(C`ev_async\*(C'\fR watcher is required because otherwise |
4099 | 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 |
4100 | 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 |
4101 | about the newly added timer. By waking up the loop it will pick up any new |
3943 | watchers in the next event loop iteration. |
4102 | 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" |
4103 | .SS "\s-1THREADS, COROUTINES, CONTINUATIONS, QUEUES... INSTEAD OF CALLBACKS\s0" |
3945 | .IX Subsection "THREADS, COROUTINES, CONTINUATIONS, QUEUES... INSTEAD OF CALLBACKS" |
4104 | .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 |
4105 | 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 |
4106 | 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 |
4107 | kind of threads or coroutines, you might want to customise libev so that |
3949 | doesn't need callbacks anymore. |
4108 | doesn't need callbacks anymore. |
… | |
… | |
3971 | .PP |
4130 | .PP |
3972 | .Vb 6 |
4131 | .Vb 6 |
3973 | \& void |
4132 | \& void |
3974 | \& wait_for_event (ev_watcher *w) |
4133 | \& wait_for_event (ev_watcher *w) |
3975 | \& { |
4134 | \& { |
3976 | \& ev_cb_set (w) = current_coro; |
4135 | \& ev_set_cb (w, current_coro); |
3977 | \& switch_to (libev_coro); |
4136 | \& switch_to (libev_coro); |
3978 | \& } |
4137 | \& } |
3979 | .Ve |
4138 | .Ve |
3980 | .PP |
4139 | .PP |
3981 | That basically suspends the coroutine inside \f(CW\*(C`wait_for_event\*(C'\fR and |
4140 | 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 \- |
4144 | 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 |
4145 | 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 |
4146 | switching to a coroutine, you push the watcher onto the queue and notify |
3988 | any waiters. |
4147 | any waiters. |
3989 | .PP |
4148 | .PP |
3990 | To embed libev, see \s-1EMBEDDING\s0, but in short, it's easiest to create two |
4149 | 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: |
4150 | files, \fImy_ev.h\fR and \fImy_ev.c\fR that include the respective libev files: |
3992 | .PP |
4151 | .PP |
3993 | .Vb 4 |
4152 | .Vb 4 |
3994 | \& // my_ev.h |
4153 | \& // my_ev.h |
3995 | \& #define EV_CB_DECLARE(type) struct my_coro *cb; |
4154 | \& #define EV_CB_DECLARE(type) struct my_coro *cb; |
3996 | \& #define EV_CB_INVOKE(watcher) switch_to ((watcher)\->cb); |
4155 | \& #define EV_CB_INVOKE(watcher) switch_to ((watcher)\->cb) |
3997 | \& #include "../libev/ev.h" |
4156 | \& #include "../libev/ev.h" |
3998 | \& |
4157 | \& |
3999 | \& // my_ev.c |
4158 | \& // my_ev.c |
4000 | \& #define EV_H "my_ev.h" |
4159 | \& #define EV_H "my_ev.h" |
4001 | \& #include "../libev/ev.c" |
4160 | \& #include "../libev/ev.c" |
… | |
… | |
4034 | .IP "\(bu" 4 |
4193 | .IP "\(bu" 4 |
4035 | The libev emulation is \fInot\fR \s-1ABI\s0 compatible to libevent, you need |
4194 | The libev emulation is \fInot\fR \s-1ABI\s0 compatible to libevent, you need |
4036 | to use the libev header file and library. |
4195 | to use the libev header file and library. |
4037 | .SH "\*(C+ SUPPORT" |
4196 | .SH "\*(C+ SUPPORT" |
4038 | .IX Header " SUPPORT" |
4197 | .IX Header " SUPPORT" |
|
|
4198 | .SS "C \s-1API\s0" |
|
|
4199 | .IX Subsection "C API" |
|
|
4200 | The normal C \s-1API\s0 should work fine when used from \*(C+: both ev.h and the |
|
|
4201 | libev sources can be compiled as \*(C+. Therefore, code that uses the C \s-1API\s0 |
|
|
4202 | will work fine. |
|
|
4203 | .PP |
|
|
4204 | Proper exception specifications might have to be added to callbacks passed |
|
|
4205 | to libev: exceptions may be thrown only from watcher callbacks, all other |
|
|
4206 | callbacks (allocator, syserr, loop acquire/release and periodic reschedule |
|
|
4207 | callbacks) must not throw exceptions, and might need a \f(CW\*(C`noexcept\*(C'\fR |
|
|
4208 | specification. If you have code that needs to be compiled as both C and |
|
|
4209 | \&\*(C+ you can use the \f(CW\*(C`EV_NOEXCEPT\*(C'\fR macro for this: |
|
|
4210 | .PP |
|
|
4211 | .Vb 6 |
|
|
4212 | \& static void |
|
|
4213 | \& fatal_error (const char *msg) EV_NOEXCEPT |
|
|
4214 | \& { |
|
|
4215 | \& perror (msg); |
|
|
4216 | \& abort (); |
|
|
4217 | \& } |
|
|
4218 | \& |
|
|
4219 | \& ... |
|
|
4220 | \& ev_set_syserr_cb (fatal_error); |
|
|
4221 | .Ve |
|
|
4222 | .PP |
|
|
4223 | The only \s-1API\s0 functions that can currently throw exceptions are \f(CW\*(C`ev_run\*(C'\fR, |
|
|
4224 | \&\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 |
|
|
4225 | because it runs cleanup watchers). |
|
|
4226 | .PP |
|
|
4227 | Throwing exceptions in watcher callbacks is only supported if libev itself |
|
|
4228 | is compiled with a \*(C+ compiler or your C and \*(C+ environments allow |
|
|
4229 | throwing exceptions through C libraries (most do). |
|
|
4230 | .SS "\*(C+ \s-1API\s0" |
|
|
4231 | .IX Subsection " API" |
4039 | Libev comes with some simplistic wrapper classes for \*(C+ that mainly allow |
4232 | Libev comes with some simplistic wrapper classes for \*(C+ that mainly allow |
4040 | you to use some convenience methods to start/stop watchers and also change |
4233 | you to use some convenience methods to start/stop watchers and also change |
4041 | the callback model to a model using method callbacks on objects. |
4234 | the callback model to a model using method callbacks on objects. |
4042 | .PP |
4235 | .PP |
4043 | To use it, |
4236 | To use it, |
… | |
… | |
4153 | \& void operator() (ev::io &w, int revents) |
4346 | \& void operator() (ev::io &w, int revents) |
4154 | \& { |
4347 | \& { |
4155 | \& ... |
4348 | \& ... |
4156 | \& } |
4349 | \& } |
4157 | \& } |
4350 | \& } |
4158 | \& |
4351 | \& |
4159 | \& myfunctor f; |
4352 | \& myfunctor f; |
4160 | \& |
4353 | \& |
4161 | \& ev::io w; |
4354 | \& ev::io w; |
4162 | \& w.set (&f); |
4355 | \& w.set (&f); |
4163 | .Ve |
4356 | .Ve |
… | |
… | |
4181 | .IX Item "w->set (loop)" |
4374 | .IX Item "w->set (loop)" |
4182 | Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only |
4375 | Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only |
4183 | do this when the watcher is inactive (and not pending either). |
4376 | do this when the watcher is inactive (and not pending either). |
4184 | .IP "w\->set ([arguments])" 4 |
4377 | .IP "w\->set ([arguments])" 4 |
4185 | .IX Item "w->set ([arguments])" |
4378 | .IX Item "w->set ([arguments])" |
4186 | Basically the same as \f(CW\*(C`ev_TYPE_set\*(C'\fR, with the same arguments. Either this |
4379 | Basically the same as \f(CW\*(C`ev_TYPE_set\*(C'\fR (except for \f(CW\*(C`ev::embed\*(C'\fR watchers>), |
4187 | method or a suitable start method must be called at least once. Unlike the |
4380 | with the same arguments. Either this method or a suitable start method |
4188 | C counterpart, an active watcher gets automatically stopped and restarted |
4381 | must be called at least once. Unlike the C counterpart, an active watcher |
4189 | when reconfiguring it with this method. |
4382 | gets automatically stopped and restarted when reconfiguring it with this |
|
|
4383 | method. |
|
|
4384 | .Sp |
|
|
4385 | For \f(CW\*(C`ev::embed\*(C'\fR watchers this method is called \f(CW\*(C`set_embed\*(C'\fR, to avoid |
|
|
4386 | clashing with the \f(CW\*(C`set (loop)\*(C'\fR method. |
4190 | .IP "w\->start ()" 4 |
4387 | .IP "w\->start ()" 4 |
4191 | .IX Item "w->start ()" |
4388 | .IX Item "w->start ()" |
4192 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument, as the |
4389 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument, as the |
4193 | constructor already stores the event loop. |
4390 | constructor already stores the event loop. |
4194 | .IP "w\->start ([arguments])" 4 |
4391 | .IP "w\->start ([arguments])" 4 |
… | |
… | |
4252 | there are additional modules that implement libev-compatible interfaces |
4449 | there are additional modules that implement libev-compatible interfaces |
4253 | 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), |
4450 | 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), |
4254 | \&\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 |
4451 | \&\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 |
4255 | and \f(CW\*(C`EV::Glib\*(C'\fR). |
4452 | and \f(CW\*(C`EV::Glib\*(C'\fR). |
4256 | .Sp |
4453 | .Sp |
4257 | It can be found and installed via \s-1CPAN\s0, its homepage is at |
4454 | It can be found and installed via \s-1CPAN,\s0 its homepage is at |
4258 | <http://software.schmorp.de/pkg/EV>. |
4455 | <http://software.schmorp.de/pkg/EV>. |
4259 | .IP "Python" 4 |
4456 | .IP "Python" 4 |
4260 | .IX Item "Python" |
4457 | .IX Item "Python" |
4261 | Python bindings can be found at <http://code.google.com/p/pyev/>. It |
4458 | Python bindings can be found at <http://code.google.com/p/pyev/>. It |
4262 | seems to be quite complete and well-documented. |
4459 | seems to be quite complete and well-documented. |
… | |
… | |
4270 | Roger Pack reports that using the link order \f(CW\*(C`\-lws2_32 \-lmsvcrt\-ruby\-190\*(C'\fR |
4467 | Roger Pack reports that using the link order \f(CW\*(C`\-lws2_32 \-lmsvcrt\-ruby\-190\*(C'\fR |
4271 | makes rev work even on mingw. |
4468 | makes rev work even on mingw. |
4272 | .IP "Haskell" 4 |
4469 | .IP "Haskell" 4 |
4273 | .IX Item "Haskell" |
4470 | .IX Item "Haskell" |
4274 | A haskell binding to libev is available at |
4471 | A haskell binding to libev is available at |
4275 | http://hackage.haskell.org/cgi\-bin/hackage\-scripts/package/hlibev <http://hackage.haskell.org/cgi-bin/hackage-scripts/package/hlibev>. |
4472 | <http://hackage.haskell.org/cgi\-bin/hackage\-scripts/package/hlibev>. |
4276 | .IP "D" 4 |
4473 | .IP "D" 4 |
4277 | .IX Item "D" |
4474 | .IX Item "D" |
4278 | Leandro Lucarella has written a D language binding (\fIev.d\fR) for libev, to |
4475 | Leandro Lucarella has written a D language binding (\fIev.d\fR) for libev, to |
4279 | be found at <http://www.llucax.com.ar/proj/ev.d/index.html>. |
4476 | be found at <http://www.llucax.com.ar/proj/ev.d/index.html>. |
4280 | .IP "Ocaml" 4 |
4477 | .IP "Ocaml" 4 |
4281 | .IX Item "Ocaml" |
4478 | .IX Item "Ocaml" |
4282 | Erkki Seppala has written Ocaml bindings for libev, to be found at |
4479 | Erkki Seppala has written Ocaml bindings for libev, to be found at |
4283 | http://modeemi.cs.tut.fi/~flux/software/ocaml\-ev/ <http://modeemi.cs.tut.fi/~flux/software/ocaml-ev/>. |
4480 | <http://modeemi.cs.tut.fi/~flux/software/ocaml\-ev/>. |
4284 | .IP "Lua" 4 |
4481 | .IP "Lua" 4 |
4285 | .IX Item "Lua" |
4482 | .IX Item "Lua" |
4286 | Brian Maher has written a partial interface to libev for lua (at the |
4483 | Brian Maher has written a partial interface to libev for lua (at the |
4287 | time of this writing, only \f(CW\*(C`ev_io\*(C'\fR and \f(CW\*(C`ev_timer\*(C'\fR), to be found at |
4484 | time of this writing, only \f(CW\*(C`ev_io\*(C'\fR and \f(CW\*(C`ev_timer\*(C'\fR), to be found at |
4288 | http://github.com/brimworks/lua\-ev <http://github.com/brimworks/lua-ev>. |
4485 | <http://github.com/brimworks/lua\-ev>. |
|
|
4486 | .IP "Javascript" 4 |
|
|
4487 | .IX Item "Javascript" |
|
|
4488 | Node.js (<http://nodejs.org>) uses libev as the underlying event library. |
|
|
4489 | .IP "Others" 4 |
|
|
4490 | .IX Item "Others" |
|
|
4491 | There are others, and I stopped counting. |
4289 | .SH "MACRO MAGIC" |
4492 | .SH "MACRO MAGIC" |
4290 | .IX Header "MACRO MAGIC" |
4493 | .IX Header "MACRO MAGIC" |
4291 | Libev can be compiled with a variety of options, the most fundamental |
4494 | Libev can be compiled with a variety of options, the most fundamental |
4292 | of which is \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines whether (most) |
4495 | of which is \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines whether (most) |
4293 | functions and callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument. |
4496 | functions and callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument. |
… | |
… | |
4376 | .SS "\s-1FILESETS\s0" |
4579 | .SS "\s-1FILESETS\s0" |
4377 | .IX Subsection "FILESETS" |
4580 | .IX Subsection "FILESETS" |
4378 | Depending on what features you need you need to include one or more sets of files |
4581 | Depending on what features you need you need to include one or more sets of files |
4379 | in your application. |
4582 | in your application. |
4380 | .PP |
4583 | .PP |
4381 | \fI\s-1CORE\s0 \s-1EVENT\s0 \s-1LOOP\s0\fR |
4584 | \fI\s-1CORE EVENT LOOP\s0\fR |
4382 | .IX Subsection "CORE EVENT LOOP" |
4585 | .IX Subsection "CORE EVENT LOOP" |
4383 | .PP |
4586 | .PP |
4384 | To include only the libev core (all the \f(CW\*(C`ev_*\*(C'\fR functions), with manual |
4587 | To include only the libev core (all the \f(CW\*(C`ev_*\*(C'\fR functions), with manual |
4385 | configuration (no autoconf): |
4588 | configuration (no autoconf): |
4386 | .PP |
4589 | .PP |
… | |
… | |
4413 | \& ev_vars.h |
4616 | \& ev_vars.h |
4414 | \& ev_wrap.h |
4617 | \& ev_wrap.h |
4415 | \& |
4618 | \& |
4416 | \& ev_win32.c required on win32 platforms only |
4619 | \& ev_win32.c required on win32 platforms only |
4417 | \& |
4620 | \& |
4418 | \& ev_select.c only when select backend is enabled (which is enabled by default) |
4621 | \& ev_select.c only when select backend is enabled |
4419 | \& ev_poll.c only when poll backend is enabled (disabled by default) |
4622 | \& ev_poll.c only when poll backend is enabled |
4420 | \& ev_epoll.c only when the epoll backend is enabled (disabled by default) |
4623 | \& ev_epoll.c only when the epoll backend is enabled |
|
|
4624 | \& ev_linuxaio.c only when the linux aio backend is enabled |
4421 | \& ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
4625 | \& ev_kqueue.c only when the kqueue backend is enabled |
4422 | \& ev_port.c only when the solaris port backend is enabled (disabled by default) |
4626 | \& ev_port.c only when the solaris port backend is enabled |
4423 | .Ve |
4627 | .Ve |
4424 | .PP |
4628 | .PP |
4425 | \&\fIev.c\fR includes the backend files directly when enabled, so you only need |
4629 | \&\fIev.c\fR includes the backend files directly when enabled, so you only need |
4426 | to compile this single file. |
4630 | to compile this single file. |
4427 | .PP |
4631 | .PP |
4428 | \fI\s-1LIBEVENT\s0 \s-1COMPATIBILITY\s0 \s-1API\s0\fR |
4632 | \fI\s-1LIBEVENT COMPATIBILITY API\s0\fR |
4429 | .IX Subsection "LIBEVENT COMPATIBILITY API" |
4633 | .IX Subsection "LIBEVENT COMPATIBILITY API" |
4430 | .PP |
4634 | .PP |
4431 | To include the libevent compatibility \s-1API\s0, also include: |
4635 | To include the libevent compatibility \s-1API,\s0 also include: |
4432 | .PP |
4636 | .PP |
4433 | .Vb 1 |
4637 | .Vb 1 |
4434 | \& #include "event.c" |
4638 | \& #include "event.c" |
4435 | .Ve |
4639 | .Ve |
4436 | .PP |
4640 | .PP |
… | |
… | |
4438 | .PP |
4642 | .PP |
4439 | .Vb 1 |
4643 | .Vb 1 |
4440 | \& #include "event.h" |
4644 | \& #include "event.h" |
4441 | .Ve |
4645 | .Ve |
4442 | .PP |
4646 | .PP |
4443 | in the files that want to use the libevent \s-1API\s0. This also includes \fIev.h\fR. |
4647 | in the files that want to use the libevent \s-1API.\s0 This also includes \fIev.h\fR. |
4444 | .PP |
4648 | .PP |
4445 | You need the following additional files for this: |
4649 | You need the following additional files for this: |
4446 | .PP |
4650 | .PP |
4447 | .Vb 2 |
4651 | .Vb 2 |
4448 | \& event.h |
4652 | \& event.h |
4449 | \& event.c |
4653 | \& event.c |
4450 | .Ve |
4654 | .Ve |
4451 | .PP |
4655 | .PP |
4452 | \fI\s-1AUTOCONF\s0 \s-1SUPPORT\s0\fR |
4656 | \fI\s-1AUTOCONF SUPPORT\s0\fR |
4453 | .IX Subsection "AUTOCONF SUPPORT" |
4657 | .IX Subsection "AUTOCONF SUPPORT" |
4454 | .PP |
4658 | .PP |
4455 | Instead of using \f(CW\*(C`EV_STANDALONE=1\*(C'\fR and providing your configuration in |
4659 | Instead of using \f(CW\*(C`EV_STANDALONE=1\*(C'\fR and providing your configuration in |
4456 | whatever way you want, you can also \f(CW\*(C`m4_include([libev.m4])\*(C'\fR in your |
4660 | whatever way you want, you can also \f(CW\*(C`m4_include([libev.m4])\*(C'\fR in your |
4457 | \&\fIconfigure.ac\fR and leave \f(CW\*(C`EV_STANDALONE\*(C'\fR undefined. \fIev.c\fR will then |
4661 | \&\fIconfigure.ac\fR and leave \f(CW\*(C`EV_STANDALONE\*(C'\fR undefined. \fIev.c\fR will then |
… | |
… | |
4460 | For this of course you need the m4 file: |
4664 | For this of course you need the m4 file: |
4461 | .PP |
4665 | .PP |
4462 | .Vb 1 |
4666 | .Vb 1 |
4463 | \& libev.m4 |
4667 | \& libev.m4 |
4464 | .Ve |
4668 | .Ve |
4465 | .SS "\s-1PREPROCESSOR\s0 \s-1SYMBOLS/MACROS\s0" |
4669 | .SS "\s-1PREPROCESSOR SYMBOLS/MACROS\s0" |
4466 | .IX Subsection "PREPROCESSOR SYMBOLS/MACROS" |
4670 | .IX Subsection "PREPROCESSOR SYMBOLS/MACROS" |
4467 | Libev can be configured via a variety of preprocessor symbols you have to |
4671 | Libev can be configured via a variety of preprocessor symbols you have to |
4468 | define before including (or compiling) any of its files. The default in |
4672 | define before including (or compiling) any of its files. The default in |
4469 | the absence of autoconf is documented for every option. |
4673 | the absence of autoconf is documented for every option. |
4470 | .PP |
4674 | .PP |
4471 | Symbols marked with \*(L"(h)\*(R" do not change the \s-1ABI\s0, and can have different |
4675 | Symbols marked with \*(L"(h)\*(R" do not change the \s-1ABI,\s0 and can have different |
4472 | values when compiling libev vs. including \fIev.h\fR, so it is permissible |
4676 | values when compiling libev vs. including \fIev.h\fR, so it is permissible |
4473 | to redefine them before including \fIev.h\fR without breaking compatibility |
4677 | to redefine them before including \fIev.h\fR without breaking compatibility |
4474 | to a compiled library. All other symbols change the \s-1ABI\s0, which means all |
4678 | to a compiled library. All other symbols change the \s-1ABI,\s0 which means all |
4475 | users of libev and the libev code itself must be compiled with compatible |
4679 | users of libev and the libev code itself must be compiled with compatible |
4476 | settings. |
4680 | settings. |
4477 | .IP "\s-1EV_COMPAT3\s0 (h)" 4 |
4681 | .IP "\s-1EV_COMPAT3\s0 (h)" 4 |
4478 | .IX Item "EV_COMPAT3 (h)" |
4682 | .IX Item "EV_COMPAT3 (h)" |
4479 | Backwards compatibility is a major concern for libev. This is why this |
4683 | Backwards compatibility is a major concern for libev. This is why this |
… | |
… | |
4588 | .IX Item "EV_WIN32_CLOSE_FD(fd)" |
4792 | .IX Item "EV_WIN32_CLOSE_FD(fd)" |
4589 | If programs implement their own fd to handle mapping on win32, then this |
4793 | If programs implement their own fd to handle mapping on win32, then this |
4590 | macro can be used to override the \f(CW\*(C`close\*(C'\fR function, useful to unregister |
4794 | macro can be used to override the \f(CW\*(C`close\*(C'\fR function, useful to unregister |
4591 | file descriptors again. Note that the replacement function has to close |
4795 | file descriptors again. Note that the replacement function has to close |
4592 | the underlying \s-1OS\s0 handle. |
4796 | the underlying \s-1OS\s0 handle. |
|
|
4797 | .IP "\s-1EV_USE_WSASOCKET\s0" 4 |
|
|
4798 | .IX Item "EV_USE_WSASOCKET" |
|
|
4799 | If defined to be \f(CW1\fR, libev will use \f(CW\*(C`WSASocket\*(C'\fR to create its internal |
|
|
4800 | communication socket, which works better in some environments. Otherwise, |
|
|
4801 | the normal \f(CW\*(C`socket\*(C'\fR function will be used, which works better in other |
|
|
4802 | environments. |
4593 | .IP "\s-1EV_USE_POLL\s0" 4 |
4803 | .IP "\s-1EV_USE_POLL\s0" 4 |
4594 | .IX Item "EV_USE_POLL" |
4804 | .IX Item "EV_USE_POLL" |
4595 | If defined to be \f(CW1\fR, libev will compile in support for the \f(CW\*(C`poll\*(C'\fR(2) |
4805 | If defined to be \f(CW1\fR, libev will compile in support for the \f(CW\*(C`poll\*(C'\fR(2) |
4596 | backend. Otherwise it will be enabled on non\-win32 platforms. It |
4806 | backend. Otherwise it will be enabled on non\-win32 platforms. It |
4597 | takes precedence over select. |
4807 | takes precedence over select. |
… | |
… | |
4600 | If defined to be \f(CW1\fR, libev will compile in support for the Linux |
4810 | If defined to be \f(CW1\fR, libev will compile in support for the Linux |
4601 | \&\f(CW\*(C`epoll\*(C'\fR(7) backend. Its availability will be detected at runtime, |
4811 | \&\f(CW\*(C`epoll\*(C'\fR(7) backend. Its availability will be detected at runtime, |
4602 | otherwise another method will be used as fallback. This is the preferred |
4812 | otherwise another method will be used as fallback. This is the preferred |
4603 | backend for GNU/Linux systems. If undefined, it will be enabled if the |
4813 | backend for GNU/Linux systems. If undefined, it will be enabled if the |
4604 | headers indicate GNU/Linux + Glibc 2.4 or newer, otherwise disabled. |
4814 | headers indicate GNU/Linux + Glibc 2.4 or newer, otherwise disabled. |
|
|
4815 | .IP "\s-1EV_USE_LINUXAIO\s0" 4 |
|
|
4816 | .IX Item "EV_USE_LINUXAIO" |
|
|
4817 | If defined to be \f(CW1\fR, libev will compile in support for the Linux |
|
|
4818 | aio backend. Due to it's currenbt limitations it has to be requested |
|
|
4819 | explicitly. If undefined, it will be enabled on linux, otherwise |
|
|
4820 | disabled. |
4605 | .IP "\s-1EV_USE_KQUEUE\s0" 4 |
4821 | .IP "\s-1EV_USE_KQUEUE\s0" 4 |
4606 | .IX Item "EV_USE_KQUEUE" |
4822 | .IX Item "EV_USE_KQUEUE" |
4607 | If defined to be \f(CW1\fR, libev will compile in support for the \s-1BSD\s0 style |
4823 | If defined to be \f(CW1\fR, libev will compile in support for the \s-1BSD\s0 style |
4608 | \&\f(CW\*(C`kqueue\*(C'\fR(2) backend. Its actual availability will be detected at runtime, |
4824 | \&\f(CW\*(C`kqueue\*(C'\fR(2) backend. Its actual availability will be detected at runtime, |
4609 | otherwise another method will be used as fallback. This is the preferred |
4825 | otherwise another method will be used as fallback. This is the preferred |
… | |
… | |
4634 | between threads, that is, threads can be used, but threads never run on |
4850 | between threads, that is, threads can be used, but threads never run on |
4635 | different cpus (or different cpu cores). This reduces dependencies |
4851 | different cpus (or different cpu cores). This reduces dependencies |
4636 | and makes libev faster. |
4852 | and makes libev faster. |
4637 | .IP "\s-1EV_NO_THREADS\s0" 4 |
4853 | .IP "\s-1EV_NO_THREADS\s0" 4 |
4638 | .IX Item "EV_NO_THREADS" |
4854 | .IX Item "EV_NO_THREADS" |
4639 | If defined to be \f(CW1\fR, libev will assume that it will never be called |
4855 | If defined to be \f(CW1\fR, libev will assume that it will never be called from |
4640 | from different threads, which is a stronger assumption than \f(CW\*(C`EV_NO_SMP\*(C'\fR, |
4856 | different threads (that includes signal handlers), which is a stronger |
4641 | above. This reduces dependencies and makes libev faster. |
4857 | assumption than \f(CW\*(C`EV_NO_SMP\*(C'\fR, above. This reduces dependencies and makes |
|
|
4858 | libev faster. |
4642 | .IP "\s-1EV_ATOMIC_T\s0" 4 |
4859 | .IP "\s-1EV_ATOMIC_T\s0" 4 |
4643 | .IX Item "EV_ATOMIC_T" |
4860 | .IX Item "EV_ATOMIC_T" |
4644 | Libev requires an integer type (suitable for storing \f(CW0\fR or \f(CW1\fR) whose |
4861 | Libev requires an integer type (suitable for storing \f(CW0\fR or \f(CW1\fR) whose |
4645 | access is atomic and serialised with respect to other threads or signal |
4862 | access is atomic with respect to other threads or signal contexts. No |
4646 | contexts. No such type is easily found in the C language, so you can |
4863 | such type is easily found in the C language, so you can provide your own |
4647 | provide your own type that you know is safe for your purposes. It is used |
4864 | type that you know is safe for your purposes. It is used both for signal |
4648 | both for signal handler \*(L"locking\*(R" as well as for signal and thread safety |
4865 | handler \*(L"locking\*(R" as well as for signal and thread safety in \f(CW\*(C`ev_async\*(C'\fR |
4649 | in \f(CW\*(C`ev_async\*(C'\fR watchers. |
4866 | watchers. |
4650 | .Sp |
4867 | .Sp |
4651 | In the absence of this define, libev will use \f(CW\*(C`sig_atomic_t volatile\*(C'\fR |
4868 | In the absence of this define, libev will use \f(CW\*(C`sig_atomic_t volatile\*(C'\fR |
4652 | (from \fIsignal.h\fR), which is usually good enough on most platforms, |
4869 | (from \fIsignal.h\fR), which is usually good enough on most platforms. |
4653 | although strictly speaking using a type that also implies a memory fence |
|
|
4654 | is required. |
|
|
4655 | .IP "\s-1EV_H\s0 (h)" 4 |
4870 | .IP "\s-1EV_H\s0 (h)" 4 |
4656 | .IX Item "EV_H (h)" |
4871 | .IX Item "EV_H (h)" |
4657 | The name of the \fIev.h\fR header file used to include it. The default if |
4872 | The name of the \fIev.h\fR header file used to include it. The default if |
4658 | undefined is \f(CW"ev.h"\fR in \fIevent.h\fR, \fIev.c\fR and \fIev++.h\fR. This can be |
4873 | undefined is \f(CW"ev.h"\fR in \fIevent.h\fR, \fIev.c\fR and \fIev++.h\fR. This can be |
4659 | used to virtually rename the \fIev.h\fR header file in case of conflicts. |
4874 | used to virtually rename the \fIev.h\fR header file in case of conflicts. |
… | |
… | |
4698 | all the priorities, so having many of them (hundreds) uses a lot of space |
4913 | all the priorities, so having many of them (hundreds) uses a lot of space |
4699 | and time, so using the defaults of five priorities (\-2 .. +2) is usually |
4914 | and time, so using the defaults of five priorities (\-2 .. +2) is usually |
4700 | fine. |
4915 | fine. |
4701 | .Sp |
4916 | .Sp |
4702 | If your embedding application does not need any priorities, defining these |
4917 | If your embedding application does not need any priorities, defining these |
4703 | both to \f(CW0\fR will save some memory and \s-1CPU\s0. |
4918 | both to \f(CW0\fR will save some memory and \s-1CPU.\s0 |
4704 | .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 |
4919 | .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 |
4705 | .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." |
4920 | .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." |
4706 | If undefined or defined to be \f(CW1\fR (and the platform supports it), then |
4921 | If undefined or defined to be \f(CW1\fR (and the platform supports it), then |
4707 | the respective watcher type is supported. If defined to be \f(CW0\fR, then it |
4922 | the respective watcher type is supported. If defined to be \f(CW0\fR, then it |
4708 | is not. Disabling watcher types mainly saves code size. |
4923 | is not. Disabling watcher types mainly saves code size. |
4709 | .IP "\s-1EV_FEATURES\s0" 4 |
4924 | .IP "\s-1EV_FEATURES\s0" 4 |
… | |
… | |
4726 | \& #define EV_CHILD_ENABLE 1 |
4941 | \& #define EV_CHILD_ENABLE 1 |
4727 | \& #define EV_ASYNC_ENABLE 1 |
4942 | \& #define EV_ASYNC_ENABLE 1 |
4728 | .Ve |
4943 | .Ve |
4729 | .Sp |
4944 | .Sp |
4730 | The actual value is a bitset, it can be a combination of the following |
4945 | The actual value is a bitset, it can be a combination of the following |
4731 | values: |
4946 | values (by default, all of these are enabled): |
4732 | .RS 4 |
4947 | .RS 4 |
4733 | .ie n .IP "1 \- faster/larger code" 4 |
4948 | .ie n .IP "1 \- faster/larger code" 4 |
4734 | .el .IP "\f(CW1\fR \- faster/larger code" 4 |
4949 | .el .IP "\f(CW1\fR \- faster/larger code" 4 |
4735 | .IX Item "1 - faster/larger code" |
4950 | .IX Item "1 - faster/larger code" |
4736 | Use larger code to speed up some operations. |
4951 | Use larger code to speed up some operations. |
… | |
… | |
4739 | code size by roughly 30% on amd64). |
4954 | code size by roughly 30% on amd64). |
4740 | .Sp |
4955 | .Sp |
4741 | When optimising for size, use of compiler flags such as \f(CW\*(C`\-Os\*(C'\fR with |
4956 | When optimising for size, use of compiler flags such as \f(CW\*(C`\-Os\*(C'\fR with |
4742 | gcc is recommended, as well as \f(CW\*(C`\-DNDEBUG\*(C'\fR, as libev contains a number of |
4957 | gcc is recommended, as well as \f(CW\*(C`\-DNDEBUG\*(C'\fR, as libev contains a number of |
4743 | assertions. |
4958 | assertions. |
|
|
4959 | .Sp |
|
|
4960 | The default is off when \f(CW\*(C`_\|_OPTIMIZE_SIZE_\|_\*(C'\fR is defined by your compiler |
|
|
4961 | (e.g. gcc with \f(CW\*(C`\-Os\*(C'\fR). |
4744 | .ie n .IP "2 \- faster/larger data structures" 4 |
4962 | .ie n .IP "2 \- faster/larger data structures" 4 |
4745 | .el .IP "\f(CW2\fR \- faster/larger data structures" 4 |
4963 | .el .IP "\f(CW2\fR \- faster/larger data structures" 4 |
4746 | .IX Item "2 - faster/larger data structures" |
4964 | .IX Item "2 - faster/larger data structures" |
4747 | Replaces the small 2\-heap for timer management by a faster 4\-heap, larger |
4965 | Replaces the small 2\-heap for timer management by a faster 4\-heap, larger |
4748 | hash table sizes and so on. This will usually further increase code size |
4966 | hash table sizes and so on. This will usually further increase code size |
4749 | and can additionally have an effect on the size of data structures at |
4967 | and can additionally have an effect on the size of data structures at |
4750 | runtime. |
4968 | runtime. |
|
|
4969 | .Sp |
|
|
4970 | The default is off when \f(CW\*(C`_\|_OPTIMIZE_SIZE_\|_\*(C'\fR is defined by your compiler |
|
|
4971 | (e.g. gcc with \f(CW\*(C`\-Os\*(C'\fR). |
4751 | .ie n .IP "4 \- full \s-1API\s0 configuration" 4 |
4972 | .ie n .IP "4 \- full \s-1API\s0 configuration" 4 |
4752 | .el .IP "\f(CW4\fR \- full \s-1API\s0 configuration" 4 |
4973 | .el .IP "\f(CW4\fR \- full \s-1API\s0 configuration" 4 |
4753 | .IX Item "4 - full API configuration" |
4974 | .IX Item "4 - full API configuration" |
4754 | This enables priorities (sets \f(CW\*(C`EV_MAXPRI\*(C'\fR=2 and \f(CW\*(C`EV_MINPRI\*(C'\fR=\-2), and |
4975 | This enables priorities (sets \f(CW\*(C`EV_MAXPRI\*(C'\fR=2 and \f(CW\*(C`EV_MINPRI\*(C'\fR=\-2), and |
4755 | enables multiplicity (\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR=1). |
4976 | enables multiplicity (\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR=1). |
… | |
… | |
4891 | and the way callbacks are invoked and set. Must expand to a struct member |
5112 | and the way callbacks are invoked and set. Must expand to a struct member |
4892 | definition and a statement, respectively. See the \fIev.h\fR header file for |
5113 | definition and a statement, respectively. See the \fIev.h\fR header file for |
4893 | their default definitions. One possible use for overriding these is to |
5114 | their default definitions. One possible use for overriding these is to |
4894 | avoid the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument in all cases, or to use |
5115 | avoid the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument in all cases, or to use |
4895 | method calls instead of plain function calls in \*(C+. |
5116 | method calls instead of plain function calls in \*(C+. |
4896 | .SS "\s-1EXPORTED\s0 \s-1API\s0 \s-1SYMBOLS\s0" |
5117 | .SS "\s-1EXPORTED API SYMBOLS\s0" |
4897 | .IX Subsection "EXPORTED API SYMBOLS" |
5118 | .IX Subsection "EXPORTED API SYMBOLS" |
4898 | If you need to re-export the \s-1API\s0 (e.g. via a \s-1DLL\s0) and you need a list of |
5119 | If you need to re-export the \s-1API\s0 (e.g. via a \s-1DLL\s0) and you need a list of |
4899 | exported symbols, you can use the provided \fISymbol.*\fR files which list |
5120 | exported symbols, you can use the provided \fISymbol.*\fR files which list |
4900 | all public symbols, one per line: |
5121 | all public symbols, one per line: |
4901 | .PP |
5122 | .PP |
… | |
… | |
4955 | \& #include "ev_cpp.h" |
5176 | \& #include "ev_cpp.h" |
4956 | \& #include "ev.c" |
5177 | \& #include "ev.c" |
4957 | .Ve |
5178 | .Ve |
4958 | .SH "INTERACTION WITH OTHER PROGRAMS, LIBRARIES OR THE ENVIRONMENT" |
5179 | .SH "INTERACTION WITH OTHER PROGRAMS, LIBRARIES OR THE ENVIRONMENT" |
4959 | .IX Header "INTERACTION WITH OTHER PROGRAMS, LIBRARIES OR THE ENVIRONMENT" |
5180 | .IX Header "INTERACTION WITH OTHER PROGRAMS, LIBRARIES OR THE ENVIRONMENT" |
4960 | .SS "\s-1THREADS\s0 \s-1AND\s0 \s-1COROUTINES\s0" |
5181 | .SS "\s-1THREADS AND COROUTINES\s0" |
4961 | .IX Subsection "THREADS AND COROUTINES" |
5182 | .IX Subsection "THREADS AND COROUTINES" |
4962 | \fI\s-1THREADS\s0\fR |
5183 | \fI\s-1THREADS\s0\fR |
4963 | .IX Subsection "THREADS" |
5184 | .IX Subsection "THREADS" |
4964 | .PP |
5185 | .PP |
4965 | All libev functions are reentrant and thread-safe unless explicitly |
5186 | All libev functions are reentrant and thread-safe unless explicitly |
… | |
… | |
5011 | An example use would be to communicate signals or other events that only |
5232 | An example use would be to communicate signals or other events that only |
5012 | work in the default loop by registering the signal watcher with the |
5233 | work in the default loop by registering the signal watcher with the |
5013 | default loop and triggering an \f(CW\*(C`ev_async\*(C'\fR watcher from the default loop |
5234 | default loop and triggering an \f(CW\*(C`ev_async\*(C'\fR watcher from the default loop |
5014 | watcher callback into the event loop interested in the signal. |
5235 | watcher callback into the event loop interested in the signal. |
5015 | .PP |
5236 | .PP |
5016 | See also \*(L"\s-1THREAD\s0 \s-1LOCKING\s0 \s-1EXAMPLE\s0\*(R". |
5237 | See also \*(L"\s-1THREAD LOCKING EXAMPLE\*(R"\s0. |
5017 | .PP |
5238 | .PP |
5018 | \fI\s-1COROUTINES\s0\fR |
5239 | \fI\s-1COROUTINES\s0\fR |
5019 | .IX Subsection "COROUTINES" |
5240 | .IX Subsection "COROUTINES" |
5020 | .PP |
5241 | .PP |
5021 | Libev is very accommodating to coroutines (\*(L"cooperative threads\*(R"): |
5242 | Libev is very accommodating to coroutines (\*(L"cooperative threads\*(R"): |
… | |
… | |
5026 | that you must not do this from \f(CW\*(C`ev_periodic\*(C'\fR reschedule callbacks. |
5247 | that you must not do this from \f(CW\*(C`ev_periodic\*(C'\fR reschedule callbacks. |
5027 | .PP |
5248 | .PP |
5028 | Care has been taken to ensure that libev does not keep local state inside |
5249 | Care has been taken to ensure that libev does not keep local state inside |
5029 | \&\f(CW\*(C`ev_run\*(C'\fR, and other calls do not usually allow for coroutine switches as |
5250 | \&\f(CW\*(C`ev_run\*(C'\fR, and other calls do not usually allow for coroutine switches as |
5030 | they do not call any callbacks. |
5251 | they do not call any callbacks. |
5031 | .SS "\s-1COMPILER\s0 \s-1WARNINGS\s0" |
5252 | .SS "\s-1COMPILER WARNINGS\s0" |
5032 | .IX Subsection "COMPILER WARNINGS" |
5253 | .IX Subsection "COMPILER WARNINGS" |
5033 | Depending on your compiler and compiler settings, you might get no or a |
5254 | Depending on your compiler and compiler settings, you might get no or a |
5034 | lot of warnings when compiling libev code. Some people are apparently |
5255 | lot of warnings when compiling libev code. Some people are apparently |
5035 | scared by this. |
5256 | scared by this. |
5036 | .PP |
5257 | .PP |
… | |
… | |
5088 | .PP |
5309 | .PP |
5089 | If you need, for some reason, empty reports from valgrind for your project |
5310 | If you need, for some reason, empty reports from valgrind for your project |
5090 | I suggest using suppression lists. |
5311 | I suggest using suppression lists. |
5091 | .SH "PORTABILITY NOTES" |
5312 | .SH "PORTABILITY NOTES" |
5092 | .IX Header "PORTABILITY NOTES" |
5313 | .IX Header "PORTABILITY NOTES" |
5093 | .SS "\s-1GNU/LINUX\s0 32 \s-1BIT\s0 \s-1LIMITATIONS\s0" |
5314 | .SS "\s-1GNU/LINUX 32 BIT LIMITATIONS\s0" |
5094 | .IX Subsection "GNU/LINUX 32 BIT LIMITATIONS" |
5315 | .IX Subsection "GNU/LINUX 32 BIT LIMITATIONS" |
5095 | GNU/Linux is the only common platform that supports 64 bit file/large file |
5316 | GNU/Linux is the only common platform that supports 64 bit file/large file |
5096 | interfaces but \fIdisables\fR them by default. |
5317 | interfaces but \fIdisables\fR them by default. |
5097 | .PP |
5318 | .PP |
5098 | That means that libev compiled in the default environment doesn't support |
5319 | That means that libev compiled in the default environment doesn't support |
5099 | files larger than 2GiB or so, which mainly affects \f(CW\*(C`ev_stat\*(C'\fR watchers. |
5320 | files larger than 2GiB or so, which mainly affects \f(CW\*(C`ev_stat\*(C'\fR watchers. |
5100 | .PP |
5321 | .PP |
5101 | Unfortunately, many programs try to work around this GNU/Linux issue |
5322 | Unfortunately, many programs try to work around this GNU/Linux issue |
5102 | by enabling the large file \s-1API\s0, which makes them incompatible with the |
5323 | by enabling the large file \s-1API,\s0 which makes them incompatible with the |
5103 | standard libev compiled for their system. |
5324 | standard libev compiled for their system. |
5104 | .PP |
5325 | .PP |
5105 | Likewise, libev cannot enable the large file \s-1API\s0 itself as this would |
5326 | Likewise, libev cannot enable the large file \s-1API\s0 itself as this would |
5106 | suddenly make it incompatible to the default compile time environment, |
5327 | suddenly make it incompatible to the default compile time environment, |
5107 | i.e. all programs not using special compile switches. |
5328 | i.e. all programs not using special compile switches. |
5108 | .SS "\s-1OS/X\s0 \s-1AND\s0 \s-1DARWIN\s0 \s-1BUGS\s0" |
5329 | .SS "\s-1OS/X AND DARWIN BUGS\s0" |
5109 | .IX Subsection "OS/X AND DARWIN BUGS" |
5330 | .IX Subsection "OS/X AND DARWIN BUGS" |
5110 | The whole thing is a bug if you ask me \- basically any system interface |
5331 | The whole thing is a bug if you ask me \- basically any system interface |
5111 | you touch is broken, whether it is locales, poll, kqueue or even the |
5332 | you touch is broken, whether it is locales, poll, kqueue or even the |
5112 | OpenGL drivers. |
5333 | OpenGL drivers. |
5113 | .PP |
5334 | .PP |
… | |
… | |
5135 | .PP |
5356 | .PP |
5136 | \fI\f(CI\*(C`select\*(C'\fI is buggy\fR |
5357 | \fI\f(CI\*(C`select\*(C'\fI is buggy\fR |
5137 | .IX Subsection "select is buggy" |
5358 | .IX Subsection "select is buggy" |
5138 | .PP |
5359 | .PP |
5139 | All that's left is \f(CW\*(C`select\*(C'\fR, and of course Apple found a way to fuck this |
5360 | All that's left is \f(CW\*(C`select\*(C'\fR, and of course Apple found a way to fuck this |
5140 | one up as well: On \s-1OS/X\s0, \f(CW\*(C`select\*(C'\fR actively limits the number of file |
5361 | one up as well: On \s-1OS/X,\s0 \f(CW\*(C`select\*(C'\fR actively limits the number of file |
5141 | descriptors you can pass in to 1024 \- your program suddenly crashes when |
5362 | descriptors you can pass in to 1024 \- your program suddenly crashes when |
5142 | you use more. |
5363 | you use more. |
5143 | .PP |
5364 | .PP |
5144 | There is an undocumented \*(L"workaround\*(R" for this \- defining |
5365 | There is an undocumented \*(L"workaround\*(R" for this \- defining |
5145 | \&\f(CW\*(C`_DARWIN_UNLIMITED_SELECT\*(C'\fR, which libev tries to use, so select \fIshould\fR |
5366 | \&\f(CW\*(C`_DARWIN_UNLIMITED_SELECT\*(C'\fR, which libev tries to use, so select \fIshould\fR |
5146 | work on \s-1OS/X\s0. |
5367 | work on \s-1OS/X.\s0 |
5147 | .SS "\s-1SOLARIS\s0 \s-1PROBLEMS\s0 \s-1AND\s0 \s-1WORKAROUNDS\s0" |
5368 | .SS "\s-1SOLARIS PROBLEMS AND WORKAROUNDS\s0" |
5148 | .IX Subsection "SOLARIS PROBLEMS AND WORKAROUNDS" |
5369 | .IX Subsection "SOLARIS PROBLEMS AND WORKAROUNDS" |
5149 | \fI\f(CI\*(C`errno\*(C'\fI reentrancy\fR |
5370 | \fI\f(CI\*(C`errno\*(C'\fI reentrancy\fR |
5150 | .IX Subsection "errno reentrancy" |
5371 | .IX Subsection "errno reentrancy" |
5151 | .PP |
5372 | .PP |
5152 | The default compile environment on Solaris is unfortunately so |
5373 | The default compile environment on Solaris is unfortunately so |
… | |
… | |
5169 | great. |
5390 | great. |
5170 | .PP |
5391 | .PP |
5171 | If you can't get it to work, you can try running the program by setting |
5392 | If you can't get it to work, you can try running the program by setting |
5172 | the environment variable \f(CW\*(C`LIBEV_FLAGS=3\*(C'\fR to only allow \f(CW\*(C`poll\*(C'\fR and |
5393 | the environment variable \f(CW\*(C`LIBEV_FLAGS=3\*(C'\fR to only allow \f(CW\*(C`poll\*(C'\fR and |
5173 | \&\f(CW\*(C`select\*(C'\fR backends. |
5394 | \&\f(CW\*(C`select\*(C'\fR backends. |
5174 | .SS "\s-1AIX\s0 \s-1POLL\s0 \s-1BUG\s0" |
5395 | .SS "\s-1AIX POLL BUG\s0" |
5175 | .IX Subsection "AIX POLL BUG" |
5396 | .IX Subsection "AIX POLL BUG" |
5176 | \&\s-1AIX\s0 unfortunately has a broken \f(CW\*(C`poll.h\*(C'\fR header. Libev works around |
5397 | \&\s-1AIX\s0 unfortunately has a broken \f(CW\*(C`poll.h\*(C'\fR header. Libev works around |
5177 | this by trying to avoid the poll backend altogether (i.e. it's not even |
5398 | this by trying to avoid the poll backend altogether (i.e. it's not even |
5178 | compiled in), which normally isn't a big problem as \f(CW\*(C`select\*(C'\fR works fine |
5399 | compiled in), which normally isn't a big problem as \f(CW\*(C`select\*(C'\fR works fine |
5179 | with large bitsets on \s-1AIX\s0, and \s-1AIX\s0 is dead anyway. |
5400 | with large bitsets on \s-1AIX,\s0 and \s-1AIX\s0 is dead anyway. |
5180 | .SS "\s-1WIN32\s0 \s-1PLATFORM\s0 \s-1LIMITATIONS\s0 \s-1AND\s0 \s-1WORKAROUNDS\s0" |
5401 | .SS "\s-1WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS\s0" |
5181 | .IX Subsection "WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS" |
5402 | .IX Subsection "WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS" |
5182 | \fIGeneral issues\fR |
5403 | \fIGeneral issues\fR |
5183 | .IX Subsection "General issues" |
5404 | .IX Subsection "General issues" |
5184 | .PP |
5405 | .PP |
5185 | Win32 doesn't support any of the standards (e.g. \s-1POSIX\s0) that libev |
5406 | Win32 doesn't support any of the standards (e.g. \s-1POSIX\s0) that libev |
… | |
… | |
5254 | \& #define EV_USE_SELECT 1 |
5475 | \& #define EV_USE_SELECT 1 |
5255 | \& #define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */ |
5476 | \& #define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */ |
5256 | .Ve |
5477 | .Ve |
5257 | .PP |
5478 | .PP |
5258 | Note that winsockets handling of fd sets is O(n), so you can easily get a |
5479 | Note that winsockets handling of fd sets is O(n), so you can easily get a |
5259 | complexity in the O(nA\*^X) range when using win32. |
5480 | complexity in the O(nX) range when using win32. |
5260 | .PP |
5481 | .PP |
5261 | \fILimited number of file descriptors\fR |
5482 | \fILimited number of file descriptors\fR |
5262 | .IX Subsection "Limited number of file descriptors" |
5483 | .IX Subsection "Limited number of file descriptors" |
5263 | .PP |
5484 | .PP |
5264 | Windows has numerous arbitrary (and low) limits on things. |
5485 | Windows has numerous arbitrary (and low) limits on things. |
… | |
… | |
5280 | by calling \f(CW\*(C`_setmaxstdio\*(C'\fR, which can increase this limit to \f(CW2048\fR |
5501 | by calling \f(CW\*(C`_setmaxstdio\*(C'\fR, which can increase this limit to \f(CW2048\fR |
5281 | (another arbitrary limit), but is broken in many versions of the Microsoft |
5502 | (another arbitrary limit), but is broken in many versions of the Microsoft |
5282 | runtime libraries. This might get you to about \f(CW512\fR or \f(CW2048\fR sockets |
5503 | runtime libraries. This might get you to about \f(CW512\fR or \f(CW2048\fR sockets |
5283 | (depending on windows version and/or the phase of the moon). To get more, |
5504 | (depending on windows version and/or the phase of the moon). To get more, |
5284 | you need to wrap all I/O functions and provide your own fd management, but |
5505 | you need to wrap all I/O functions and provide your own fd management, but |
5285 | the cost of calling select (O(nA\*^X)) will likely make this unworkable. |
5506 | the cost of calling select (O(nX)) will likely make this unworkable. |
5286 | .SS "\s-1PORTABILITY\s0 \s-1REQUIREMENTS\s0" |
5507 | .SS "\s-1PORTABILITY REQUIREMENTS\s0" |
5287 | .IX Subsection "PORTABILITY REQUIREMENTS" |
5508 | .IX Subsection "PORTABILITY REQUIREMENTS" |
5288 | In addition to a working ISO-C implementation and of course the |
5509 | In addition to a working ISO-C implementation and of course the |
5289 | backend-specific APIs, libev relies on a few additional extensions: |
5510 | backend-specific APIs, libev relies on a few additional extensions: |
5290 | .ie n .IP """void (*)(ev_watcher_type *, int revents)"" must have compatible calling conventions regardless of ""ev_watcher_type *""." 4 |
5511 | .ie n .IP """void (*)(ev_watcher_type *, int revents)"" must have compatible calling conventions regardless of ""ev_watcher_type *""." 4 |
5291 | .el .IP "\f(CWvoid (*)(ev_watcher_type *, int revents)\fR must have compatible calling conventions regardless of \f(CWev_watcher_type *\fR." 4 |
5512 | .el .IP "\f(CWvoid (*)(ev_watcher_type *, int revents)\fR must have compatible calling conventions regardless of \f(CWev_watcher_type *\fR." 4 |
5292 | .IX Item "void (*)(ev_watcher_type *, int revents) must have compatible calling conventions regardless of ev_watcher_type *." |
5513 | .IX Item "void (*)(ev_watcher_type *, int revents) must have compatible calling conventions regardless of ev_watcher_type *." |
5293 | Libev assumes not only that all watcher pointers have the same internal |
5514 | Libev assumes not only that all watcher pointers have the same internal |
5294 | structure (guaranteed by \s-1POSIX\s0 but not by \s-1ISO\s0 C for example), but it also |
5515 | structure (guaranteed by \s-1POSIX\s0 but not by \s-1ISO C\s0 for example), but it also |
5295 | assumes that the same (machine) code can be used to call any watcher |
5516 | assumes that the same (machine) code can be used to call any watcher |
5296 | callback: The watcher callbacks have different type signatures, but libev |
5517 | callback: The watcher callbacks have different type signatures, but libev |
5297 | calls them using an \f(CW\*(C`ev_watcher *\*(C'\fR internally. |
5518 | calls them using an \f(CW\*(C`ev_watcher *\*(C'\fR internally. |
|
|
5519 | .IP "null pointers and integer zero are represented by 0 bytes" 4 |
|
|
5520 | .IX Item "null pointers and integer zero are represented by 0 bytes" |
|
|
5521 | Libev uses \f(CW\*(C`memset\*(C'\fR to initialise structs and arrays to \f(CW0\fR bytes, and |
|
|
5522 | relies on this setting pointers and integers to null. |
5298 | .IP "pointer accesses must be thread-atomic" 4 |
5523 | .IP "pointer accesses must be thread-atomic" 4 |
5299 | .IX Item "pointer accesses must be thread-atomic" |
5524 | .IX Item "pointer accesses must be thread-atomic" |
5300 | Accessing a pointer value must be atomic, it must both be readable and |
5525 | Accessing a pointer value must be atomic, it must both be readable and |
5301 | writable in one piece \- this is the case on all current architectures. |
5526 | writable in one piece \- this is the case on all current architectures. |
5302 | .ie n .IP """sig_atomic_t volatile"" must be thread-atomic as well" 4 |
5527 | .ie n .IP """sig_atomic_t volatile"" must be thread-atomic as well" 4 |
… | |
… | |
5315 | thread\*(R" or will block signals process-wide, both behaviours would |
5540 | thread\*(R" or will block signals process-wide, both behaviours would |
5316 | be compatible with libev. Interaction between \f(CW\*(C`sigprocmask\*(C'\fR and |
5541 | be compatible with libev. Interaction between \f(CW\*(C`sigprocmask\*(C'\fR and |
5317 | \&\f(CW\*(C`pthread_sigmask\*(C'\fR could complicate things, however. |
5542 | \&\f(CW\*(C`pthread_sigmask\*(C'\fR could complicate things, however. |
5318 | .Sp |
5543 | .Sp |
5319 | The most portable way to handle signals is to block signals in all threads |
5544 | The most portable way to handle signals is to block signals in all threads |
5320 | except the initial one, and run the default loop in the initial thread as |
5545 | except the initial one, and run the signal handling loop in the initial |
5321 | well. |
5546 | thread as well. |
5322 | .ie n .IP """long"" must be large enough for common memory allocation sizes" 4 |
5547 | .ie n .IP """long"" must be large enough for common memory allocation sizes" 4 |
5323 | .el .IP "\f(CWlong\fR must be large enough for common memory allocation sizes" 4 |
5548 | .el .IP "\f(CWlong\fR must be large enough for common memory allocation sizes" 4 |
5324 | .IX Item "long must be large enough for common memory allocation sizes" |
5549 | .IX Item "long must be large enough for common memory allocation sizes" |
5325 | To improve portability and simplify its \s-1API\s0, libev uses \f(CW\*(C`long\*(C'\fR internally |
5550 | To improve portability and simplify its \s-1API,\s0 libev uses \f(CW\*(C`long\*(C'\fR internally |
5326 | instead of \f(CW\*(C`size_t\*(C'\fR when allocating its data structures. On non-POSIX |
5551 | instead of \f(CW\*(C`size_t\*(C'\fR when allocating its data structures. On non-POSIX |
5327 | systems (Microsoft...) this might be unexpectedly low, but is still at |
5552 | systems (Microsoft...) this might be unexpectedly low, but is still at |
5328 | least 31 bits everywhere, which is enough for hundreds of millions of |
5553 | least 31 bits everywhere, which is enough for hundreds of millions of |
5329 | watchers. |
5554 | watchers. |
5330 | .ie n .IP """double"" must hold a time value in seconds with enough accuracy" 4 |
5555 | .ie n .IP """double"" must hold a time value in seconds with enough accuracy" 4 |
… | |
… | |
5332 | .IX Item "double must hold a time value in seconds with enough accuracy" |
5557 | .IX Item "double must hold a time value in seconds with enough accuracy" |
5333 | The type \f(CW\*(C`double\*(C'\fR is used to represent timestamps. It is required to |
5558 | The type \f(CW\*(C`double\*(C'\fR is used to represent timestamps. It is required to |
5334 | have at least 51 bits of mantissa (and 9 bits of exponent), which is |
5559 | have at least 51 bits of mantissa (and 9 bits of exponent), which is |
5335 | good enough for at least into the year 4000 with millisecond accuracy |
5560 | good enough for at least into the year 4000 with millisecond accuracy |
5336 | (the design goal for libev). This requirement is overfulfilled by |
5561 | (the design goal for libev). This requirement is overfulfilled by |
5337 | implementations using \s-1IEEE\s0 754, which is basically all existing ones. |
5562 | implementations using \s-1IEEE 754,\s0 which is basically all existing ones. |
5338 | .Sp |
5563 | .Sp |
5339 | With \s-1IEEE\s0 754 doubles, you get microsecond accuracy until at least the |
5564 | With \s-1IEEE 754\s0 doubles, you get microsecond accuracy until at least the |
5340 | year 2255 (and millisecond accuracy till the year 287396 \- by then, libev |
5565 | year 2255 (and millisecond accuracy till the year 287396 \- by then, libev |
5341 | is either obsolete or somebody patched it to use \f(CW\*(C`long double\*(C'\fR or |
5566 | is either obsolete or somebody patched it to use \f(CW\*(C`long double\*(C'\fR or |
5342 | something like that, just kidding). |
5567 | something like that, just kidding). |
5343 | .PP |
5568 | .PP |
5344 | If you know of other additional requirements drop me a note. |
5569 | If you know of other additional requirements drop me a note. |
… | |
… | |
5406 | calls in the current loop iteration and the loop is currently |
5631 | calls in the current loop iteration and the loop is currently |
5407 | blocked. Checking for async and signal events involves iterating over all |
5632 | blocked. Checking for async and signal events involves iterating over all |
5408 | running async watchers or all signal numbers. |
5633 | running async watchers or all signal numbers. |
5409 | .SH "PORTING FROM LIBEV 3.X TO 4.X" |
5634 | .SH "PORTING FROM LIBEV 3.X TO 4.X" |
5410 | .IX Header "PORTING FROM LIBEV 3.X TO 4.X" |
5635 | .IX Header "PORTING FROM LIBEV 3.X TO 4.X" |
5411 | The major version 4 introduced some incompatible changes to the \s-1API\s0. |
5636 | The major version 4 introduced some incompatible changes to the \s-1API.\s0 |
5412 | .PP |
5637 | .PP |
5413 | At the moment, the \f(CW\*(C`ev.h\*(C'\fR header file provides compatibility definitions |
5638 | At the moment, the \f(CW\*(C`ev.h\*(C'\fR header file provides compatibility definitions |
5414 | for all changes, so most programs should still compile. The compatibility |
5639 | for all changes, so most programs should still compile. The compatibility |
5415 | layer might be removed in later versions of libev, so better update to the |
5640 | layer might be removed in later versions of libev, so better update to the |
5416 | new \s-1API\s0 early than late. |
5641 | new \s-1API\s0 early than late. |
5417 | .ie n .IP """EV_COMPAT3"" backwards compatibility mechanism" 4 |
5642 | .ie n .IP """EV_COMPAT3"" backwards compatibility mechanism" 4 |
5418 | .el .IP "\f(CWEV_COMPAT3\fR backwards compatibility mechanism" 4 |
5643 | .el .IP "\f(CWEV_COMPAT3\fR backwards compatibility mechanism" 4 |
5419 | .IX Item "EV_COMPAT3 backwards compatibility mechanism" |
5644 | .IX Item "EV_COMPAT3 backwards compatibility mechanism" |
5420 | The backward compatibility mechanism can be controlled by |
5645 | The backward compatibility mechanism can be controlled by |
5421 | \&\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 |
5646 | \&\f(CW\*(C`EV_COMPAT3\*(C'\fR. See \*(L"\s-1PREPROCESSOR SYMBOLS/MACROS\*(R"\s0 in the \*(L"\s-1EMBEDDING\*(R"\s0 |
5422 | section. |
5647 | section. |
5423 | .ie n .IP """ev_default_destroy"" and ""ev_default_fork"" have been removed" 4 |
5648 | .ie n .IP """ev_default_destroy"" and ""ev_default_fork"" have been removed" 4 |
5424 | .el .IP "\f(CWev_default_destroy\fR and \f(CWev_default_fork\fR have been removed" 4 |
5649 | .el .IP "\f(CWev_default_destroy\fR and \f(CWev_default_fork\fR have been removed" 4 |
5425 | .IX Item "ev_default_destroy and ev_default_fork have been removed" |
5650 | .IX Item "ev_default_destroy and ev_default_fork have been removed" |
5426 | These calls can be replaced easily by their \f(CW\*(C`ev_loop_xxx\*(C'\fR counterparts: |
5651 | These calls can be replaced easily by their \f(CW\*(C`ev_loop_xxx\*(C'\fR counterparts: |
… | |
… | |
5466 | .SH "GLOSSARY" |
5691 | .SH "GLOSSARY" |
5467 | .IX Header "GLOSSARY" |
5692 | .IX Header "GLOSSARY" |
5468 | .IP "active" 4 |
5693 | .IP "active" 4 |
5469 | .IX Item "active" |
5694 | .IX Item "active" |
5470 | A watcher is active as long as it has been started and not yet stopped. |
5695 | A watcher is active as long as it has been started and not yet stopped. |
5471 | See \*(L"\s-1WATCHER\s0 \s-1STATES\s0\*(R" for details. |
5696 | See \*(L"\s-1WATCHER STATES\*(R"\s0 for details. |
5472 | .IP "application" 4 |
5697 | .IP "application" 4 |
5473 | .IX Item "application" |
5698 | .IX Item "application" |
5474 | In this document, an application is whatever is using libev. |
5699 | In this document, an application is whatever is using libev. |
5475 | .IP "backend" 4 |
5700 | .IP "backend" 4 |
5476 | .IX Item "backend" |
5701 | .IX Item "backend" |
… | |
… | |
5503 | The model used to describe how an event loop handles and processes |
5728 | The model used to describe how an event loop handles and processes |
5504 | watchers and events. |
5729 | watchers and events. |
5505 | .IP "pending" 4 |
5730 | .IP "pending" 4 |
5506 | .IX Item "pending" |
5731 | .IX Item "pending" |
5507 | A watcher is pending as soon as the corresponding event has been |
5732 | A watcher is pending as soon as the corresponding event has been |
5508 | detected. See \*(L"\s-1WATCHER\s0 \s-1STATES\s0\*(R" for details. |
5733 | detected. See \*(L"\s-1WATCHER STATES\*(R"\s0 for details. |
5509 | .IP "real time" 4 |
5734 | .IP "real time" 4 |
5510 | .IX Item "real time" |
5735 | .IX Item "real time" |
5511 | The physical time that is observed. It is apparently strictly monotonic :) |
5736 | The physical time that is observed. It is apparently strictly monotonic :) |
5512 | .IP "wall-clock time" 4 |
5737 | .IP "wall-clock time" 4 |
5513 | .IX Item "wall-clock time" |
5738 | .IX Item "wall-clock time" |