… | |
… | |
260 | flags. If that is troubling you, check C<ev_backend ()> afterwards). |
260 | flags. If that is troubling you, check C<ev_backend ()> afterwards). |
261 | |
261 | |
262 | If you don't know what event loop to use, use the one returned from this |
262 | If you don't know what event loop to use, use the one returned from this |
263 | function. |
263 | function. |
264 | |
264 | |
|
|
265 | The default loop is the only loop that can handle C<ev_signal> and |
|
|
266 | C<ev_child> watchers, and to do this, it always registers a handler |
|
|
267 | for C<SIGCHLD>. If this is a problem for your app you can either |
|
|
268 | create a dynamic loop with C<ev_loop_new> that doesn't do that, or you |
|
|
269 | can simply overwrite the C<SIGCHLD> signal handler I<after> calling |
|
|
270 | C<ev_default_init>. |
|
|
271 | |
265 | The flags argument can be used to specify special behaviour or specific |
272 | The flags argument can be used to specify special behaviour or specific |
266 | backends to use, and is usually specified as C<0> (or C<EVFLAG_AUTO>). |
273 | backends to use, and is usually specified as C<0> (or C<EVFLAG_AUTO>). |
267 | |
274 | |
268 | The following flags are supported: |
275 | The following flags are supported: |
269 | |
276 | |
… | |
… | |
403 | While this backend scales well, it requires one system call per active |
410 | While this backend scales well, it requires one system call per active |
404 | file descriptor per loop iteration. For small and medium numbers of file |
411 | file descriptor per loop iteration. For small and medium numbers of file |
405 | descriptors a "slow" C<EVBACKEND_SELECT> or C<EVBACKEND_POLL> backend |
412 | descriptors a "slow" C<EVBACKEND_SELECT> or C<EVBACKEND_POLL> backend |
406 | might perform better. |
413 | might perform better. |
407 | |
414 | |
|
|
415 | On the positive side, ignoring the spurious readyness notifications, this |
|
|
416 | backend actually performed to specification in all tests and is fully |
|
|
417 | embeddable, which is a rare feat among the OS-specific backends. |
|
|
418 | |
408 | =item C<EVBACKEND_ALL> |
419 | =item C<EVBACKEND_ALL> |
409 | |
420 | |
410 | Try all backends (even potentially broken ones that wouldn't be tried |
421 | Try all backends (even potentially broken ones that wouldn't be tried |
411 | with C<EVFLAG_AUTO>). Since this is a mask, you can do stuff such as |
422 | with C<EVFLAG_AUTO>). Since this is a mask, you can do stuff such as |
412 | C<EVBACKEND_ALL & ~EVBACKEND_KQUEUE>. |
423 | C<EVBACKEND_ALL & ~EVBACKEND_KQUEUE>. |
… | |
… | |
414 | It is definitely not recommended to use this flag. |
425 | It is definitely not recommended to use this flag. |
415 | |
426 | |
416 | =back |
427 | =back |
417 | |
428 | |
418 | If one or more of these are ored into the flags value, then only these |
429 | If one or more of these are ored into the flags value, then only these |
419 | backends will be tried (in the reverse order as given here). If none are |
430 | backends will be tried (in the reverse order as listed here). If none are |
420 | specified, most compiled-in backend will be tried, usually in reverse |
431 | specified, all backends in C<ev_recommended_backends ()> will be tried. |
421 | order of their flag values :) |
|
|
422 | |
432 | |
423 | The most typical usage is like this: |
433 | The most typical usage is like this: |
424 | |
434 | |
425 | if (!ev_default_loop (0)) |
435 | if (!ev_default_loop (0)) |
426 | fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?"); |
436 | fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?"); |
… | |
… | |
473 | Like C<ev_default_destroy>, but destroys an event loop created by an |
483 | Like C<ev_default_destroy>, but destroys an event loop created by an |
474 | earlier call to C<ev_loop_new>. |
484 | earlier call to C<ev_loop_new>. |
475 | |
485 | |
476 | =item ev_default_fork () |
486 | =item ev_default_fork () |
477 | |
487 | |
|
|
488 | This function sets a flag that causes subsequent C<ev_loop> iterations |
478 | This function reinitialises the kernel state for backends that have |
489 | to reinitialise the kernel state for backends that have one. Despite the |
479 | one. Despite the name, you can call it anytime, but it makes most sense |
490 | name, you can call it anytime, but it makes most sense after forking, in |
480 | after forking, in either the parent or child process (or both, but that |
491 | the child process (or both child and parent, but that again makes little |
481 | again makes little sense). |
492 | sense). You I<must> call it in the child before using any of the libev |
|
|
493 | functions, and it will only take effect at the next C<ev_loop> iteration. |
482 | |
494 | |
483 | You I<must> call this function in the child process after forking if and |
495 | On the other hand, you only need to call this function in the child |
484 | only if you want to use the event library in both processes. If you just |
496 | process if and only if you want to use the event library in the child. If |
485 | fork+exec, you don't have to call it. |
497 | you just fork+exec, you don't have to call it at all. |
486 | |
498 | |
487 | The function itself is quite fast and it's usually not a problem to call |
499 | The function itself is quite fast and it's usually not a problem to call |
488 | it just in case after a fork. To make this easy, the function will fit in |
500 | it just in case after a fork. To make this easy, the function will fit in |
489 | quite nicely into a call to C<pthread_atfork>: |
501 | quite nicely into a call to C<pthread_atfork>: |
490 | |
502 | |
491 | pthread_atfork (0, 0, ev_default_fork); |
503 | pthread_atfork (0, 0, ev_default_fork); |
492 | |
|
|
493 | At the moment, C<EVBACKEND_SELECT> and C<EVBACKEND_POLL> are safe to use |
|
|
494 | without calling this function, so if you force one of those backends you |
|
|
495 | do not need to care. |
|
|
496 | |
504 | |
497 | =item ev_loop_fork (loop) |
505 | =item ev_loop_fork (loop) |
498 | |
506 | |
499 | Like C<ev_default_fork>, but acts on an event loop created by |
507 | Like C<ev_default_fork>, but acts on an event loop created by |
500 | C<ev_loop_new>. Yes, you have to call this on every allocated event loop |
508 | C<ev_loop_new>. Yes, you have to call this on every allocated event loop |
… | |
… | |
551 | usually a better approach for this kind of thing. |
559 | usually a better approach for this kind of thing. |
552 | |
560 | |
553 | Here are the gory details of what C<ev_loop> does: |
561 | Here are the gory details of what C<ev_loop> does: |
554 | |
562 | |
555 | - Before the first iteration, call any pending watchers. |
563 | - Before the first iteration, call any pending watchers. |
556 | * If there are no active watchers (reference count is zero), return. |
564 | * If EVFLAG_FORKCHECK was used, check for a fork. |
557 | - Queue all prepare watchers and then call all outstanding watchers. |
565 | - If a fork was detected, queue and call all fork watchers. |
|
|
566 | - Queue and call all prepare watchers. |
558 | - If we have been forked, recreate the kernel state. |
567 | - If we have been forked, recreate the kernel state. |
559 | - Update the kernel state with all outstanding changes. |
568 | - Update the kernel state with all outstanding changes. |
560 | - Update the "event loop time". |
569 | - Update the "event loop time". |
561 | - Calculate for how long to block. |
570 | - Calculate for how long to sleep or block, if at all |
|
|
571 | (active idle watchers, EVLOOP_NONBLOCK or not having |
|
|
572 | any active watchers at all will result in not sleeping). |
|
|
573 | - Sleep if the I/O and timer collect interval say so. |
562 | - Block the process, waiting for any events. |
574 | - Block the process, waiting for any events. |
563 | - Queue all outstanding I/O (fd) events. |
575 | - Queue all outstanding I/O (fd) events. |
564 | - Update the "event loop time" and do time jump handling. |
576 | - Update the "event loop time" and do time jump handling. |
565 | - Queue all outstanding timers. |
577 | - Queue all outstanding timers. |
566 | - Queue all outstanding periodics. |
578 | - Queue all outstanding periodics. |
567 | - If no events are pending now, queue all idle watchers. |
579 | - If no events are pending now, queue all idle watchers. |
568 | - Queue all check watchers. |
580 | - Queue all check watchers. |
569 | - Call all queued watchers in reverse order (i.e. check watchers first). |
581 | - Call all queued watchers in reverse order (i.e. check watchers first). |
570 | Signals and child watchers are implemented as I/O watchers, and will |
582 | Signals and child watchers are implemented as I/O watchers, and will |
571 | be handled here by queueing them when their watcher gets executed. |
583 | be handled here by queueing them when their watcher gets executed. |
572 | - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
584 | - If ev_unloop has been called, or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
573 | were used, return, otherwise continue with step *. |
585 | were used, or there are no active watchers, return, otherwise |
|
|
586 | continue with step *. |
574 | |
587 | |
575 | Example: Queue some jobs and then loop until no events are outsanding |
588 | Example: Queue some jobs and then loop until no events are outstanding |
576 | anymore. |
589 | anymore. |
577 | |
590 | |
578 | ... queue jobs here, make sure they register event watchers as long |
591 | ... queue jobs here, make sure they register event watchers as long |
579 | ... as they still have work to do (even an idle watcher will do..) |
592 | ... as they still have work to do (even an idle watcher will do..) |
580 | ev_loop (my_loop, 0); |
593 | ev_loop (my_loop, 0); |
… | |
… | |
584 | |
597 | |
585 | Can be used to make a call to C<ev_loop> return early (but only after it |
598 | Can be used to make a call to C<ev_loop> return early (but only after it |
586 | has processed all outstanding events). The C<how> argument must be either |
599 | has processed all outstanding events). The C<how> argument must be either |
587 | C<EVUNLOOP_ONE>, which will make the innermost C<ev_loop> call return, or |
600 | C<EVUNLOOP_ONE>, which will make the innermost C<ev_loop> call return, or |
588 | C<EVUNLOOP_ALL>, which will make all nested C<ev_loop> calls return. |
601 | C<EVUNLOOP_ALL>, which will make all nested C<ev_loop> calls return. |
|
|
602 | |
|
|
603 | This "unloop state" will be cleared when entering C<ev_loop> again. |
589 | |
604 | |
590 | =item ev_ref (loop) |
605 | =item ev_ref (loop) |
591 | |
606 | |
592 | =item ev_unref (loop) |
607 | =item ev_unref (loop) |
593 | |
608 | |
… | |
… | |
598 | returning, ev_unref() after starting, and ev_ref() before stopping it. For |
613 | returning, ev_unref() after starting, and ev_ref() before stopping it. For |
599 | example, libev itself uses this for its internal signal pipe: It is not |
614 | example, libev itself uses this for its internal signal pipe: It is not |
600 | visible to the libev user and should not keep C<ev_loop> from exiting if |
615 | visible to the libev user and should not keep C<ev_loop> from exiting if |
601 | no event watchers registered by it are active. It is also an excellent |
616 | no event watchers registered by it are active. It is also an excellent |
602 | way to do this for generic recurring timers or from within third-party |
617 | way to do this for generic recurring timers or from within third-party |
603 | libraries. Just remember to I<unref after start> and I<ref before stop>. |
618 | libraries. Just remember to I<unref after start> and I<ref before stop> |
|
|
619 | (but only if the watcher wasn't active before, or was active before, |
|
|
620 | respectively). |
604 | |
621 | |
605 | Example: Create a signal watcher, but keep it from keeping C<ev_loop> |
622 | Example: Create a signal watcher, but keep it from keeping C<ev_loop> |
606 | running when nothing else is active. |
623 | running when nothing else is active. |
607 | |
624 | |
608 | struct ev_signal exitsig; |
625 | struct ev_signal exitsig; |
… | |
… | |
983 | In general you can register as many read and/or write event watchers per |
1000 | In general you can register as many read and/or write event watchers per |
984 | fd as you want (as long as you don't confuse yourself). Setting all file |
1001 | fd as you want (as long as you don't confuse yourself). Setting all file |
985 | descriptors to non-blocking mode is also usually a good idea (but not |
1002 | descriptors to non-blocking mode is also usually a good idea (but not |
986 | required if you know what you are doing). |
1003 | required if you know what you are doing). |
987 | |
1004 | |
988 | You have to be careful with dup'ed file descriptors, though. Some backends |
|
|
989 | (the linux epoll backend is a notable example) cannot handle dup'ed file |
|
|
990 | descriptors correctly if you register interest in two or more fds pointing |
|
|
991 | to the same underlying file/socket/etc. description (that is, they share |
|
|
992 | the same underlying "file open"). |
|
|
993 | |
|
|
994 | If you must do this, then force the use of a known-to-be-good backend |
1005 | If you must do this, then force the use of a known-to-be-good backend |
995 | (at the time of this writing, this includes only C<EVBACKEND_SELECT> and |
1006 | (at the time of this writing, this includes only C<EVBACKEND_SELECT> and |
996 | C<EVBACKEND_POLL>). |
1007 | C<EVBACKEND_POLL>). |
997 | |
1008 | |
998 | Another thing you have to watch out for is that it is quite easy to |
1009 | Another thing you have to watch out for is that it is quite easy to |
… | |
… | |
1033 | |
1044 | |
1034 | =head3 The special problem of dup'ed file descriptors |
1045 | =head3 The special problem of dup'ed file descriptors |
1035 | |
1046 | |
1036 | Some backends (e.g. epoll), cannot register events for file descriptors, |
1047 | Some backends (e.g. epoll), cannot register events for file descriptors, |
1037 | but only events for the underlying file descriptions. That means when you |
1048 | but only events for the underlying file descriptions. That means when you |
1038 | have C<dup ()>'ed file descriptors and register events for them, only one |
1049 | have C<dup ()>'ed file descriptors or weirder constellations, and register |
1039 | file descriptor might actually receive events. |
1050 | events for them, only one file descriptor might actually receive events. |
1040 | |
1051 | |
1041 | There is no workaround possible except not registering events |
1052 | There is no workaround possible except not registering events |
1042 | for potentially C<dup ()>'ed file descriptors, or to resort to |
1053 | for potentially C<dup ()>'ed file descriptors, or to resort to |
1043 | C<EVBACKEND_SELECT> or C<EVBACKEND_POLL>. |
1054 | C<EVBACKEND_SELECT> or C<EVBACKEND_POLL>. |
1044 | |
1055 | |
… | |
… | |
1073 | =item int events [read-only] |
1084 | =item int events [read-only] |
1074 | |
1085 | |
1075 | The events being watched. |
1086 | The events being watched. |
1076 | |
1087 | |
1077 | =back |
1088 | =back |
|
|
1089 | |
|
|
1090 | =head3 Examples |
1078 | |
1091 | |
1079 | Example: Call C<stdin_readable_cb> when STDIN_FILENO has become, well |
1092 | Example: Call C<stdin_readable_cb> when STDIN_FILENO has become, well |
1080 | readable, but only once. Since it is likely line-buffered, you could |
1093 | readable, but only once. Since it is likely line-buffered, you could |
1081 | attempt to read a whole line in the callback. |
1094 | attempt to read a whole line in the callback. |
1082 | |
1095 | |
… | |
… | |
1180 | or C<ev_timer_again> is called and determines the next timeout (if any), |
1193 | or C<ev_timer_again> is called and determines the next timeout (if any), |
1181 | which is also when any modifications are taken into account. |
1194 | which is also when any modifications are taken into account. |
1182 | |
1195 | |
1183 | =back |
1196 | =back |
1184 | |
1197 | |
|
|
1198 | =head3 Examples |
|
|
1199 | |
1185 | Example: Create a timer that fires after 60 seconds. |
1200 | Example: Create a timer that fires after 60 seconds. |
1186 | |
1201 | |
1187 | static void |
1202 | static void |
1188 | one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1203 | one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1189 | { |
1204 | { |
… | |
… | |
1346 | When active, contains the absolute time that the watcher is supposed to |
1361 | When active, contains the absolute time that the watcher is supposed to |
1347 | trigger next. |
1362 | trigger next. |
1348 | |
1363 | |
1349 | =back |
1364 | =back |
1350 | |
1365 | |
|
|
1366 | =head3 Examples |
|
|
1367 | |
1351 | Example: Call a callback every hour, or, more precisely, whenever the |
1368 | Example: Call a callback every hour, or, more precisely, whenever the |
1352 | system clock is divisible by 3600. The callback invocation times have |
1369 | system clock is divisible by 3600. The callback invocation times have |
1353 | potentially a lot of jittering, but good long-term stability. |
1370 | potentially a lot of jittering, but good long-term stability. |
1354 | |
1371 | |
1355 | static void |
1372 | static void |
… | |
… | |
1421 | |
1438 | |
1422 | =head3 Watcher-Specific Functions and Data Members |
1439 | =head3 Watcher-Specific Functions and Data Members |
1423 | |
1440 | |
1424 | =over 4 |
1441 | =over 4 |
1425 | |
1442 | |
1426 | =item ev_child_init (ev_child *, callback, int pid) |
1443 | =item ev_child_init (ev_child *, callback, int pid, int trace) |
1427 | |
1444 | |
1428 | =item ev_child_set (ev_child *, int pid) |
1445 | =item ev_child_set (ev_child *, int pid, int trace) |
1429 | |
1446 | |
1430 | Configures the watcher to wait for status changes of process C<pid> (or |
1447 | Configures the watcher to wait for status changes of process C<pid> (or |
1431 | I<any> process if C<pid> is specified as C<0>). The callback can look |
1448 | I<any> process if C<pid> is specified as C<0>). The callback can look |
1432 | at the C<rstatus> member of the C<ev_child> watcher structure to see |
1449 | at the C<rstatus> member of the C<ev_child> watcher structure to see |
1433 | the status word (use the macros from C<sys/wait.h> and see your systems |
1450 | the status word (use the macros from C<sys/wait.h> and see your systems |
1434 | C<waitpid> documentation). The C<rpid> member contains the pid of the |
1451 | C<waitpid> documentation). The C<rpid> member contains the pid of the |
1435 | process causing the status change. |
1452 | process causing the status change. C<trace> must be either C<0> (only |
|
|
1453 | activate the watcher when the process terminates) or C<1> (additionally |
|
|
1454 | activate the watcher when the process is stopped or continued). |
1436 | |
1455 | |
1437 | =item int pid [read-only] |
1456 | =item int pid [read-only] |
1438 | |
1457 | |
1439 | The process id this watcher watches out for, or C<0>, meaning any process id. |
1458 | The process id this watcher watches out for, or C<0>, meaning any process id. |
1440 | |
1459 | |
… | |
… | |
1446 | |
1465 | |
1447 | The process exit/trace status caused by C<rpid> (see your systems |
1466 | The process exit/trace status caused by C<rpid> (see your systems |
1448 | C<waitpid> and C<sys/wait.h> documentation for details). |
1467 | C<waitpid> and C<sys/wait.h> documentation for details). |
1449 | |
1468 | |
1450 | =back |
1469 | =back |
|
|
1470 | |
|
|
1471 | =head3 Examples |
1451 | |
1472 | |
1452 | Example: Try to exit cleanly on SIGINT and SIGTERM. |
1473 | Example: Try to exit cleanly on SIGINT and SIGTERM. |
1453 | |
1474 | |
1454 | static void |
1475 | static void |
1455 | sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
1476 | sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
… | |
… | |
1664 | kind. There is a C<ev_idle_set> macro, but using it is utterly pointless, |
1685 | kind. There is a C<ev_idle_set> macro, but using it is utterly pointless, |
1665 | believe me. |
1686 | believe me. |
1666 | |
1687 | |
1667 | =back |
1688 | =back |
1668 | |
1689 | |
|
|
1690 | =head3 Examples |
|
|
1691 | |
1669 | Example: Dynamically allocate an C<ev_idle> watcher, start it, and in the |
1692 | Example: Dynamically allocate an C<ev_idle> watcher, start it, and in the |
1670 | callback, free it. Also, use no error checking, as usual. |
1693 | callback, free it. Also, use no error checking, as usual. |
1671 | |
1694 | |
1672 | static void |
1695 | static void |
1673 | idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
1696 | idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
… | |
… | |
1744 | parameters of any kind. There are C<ev_prepare_set> and C<ev_check_set> |
1767 | parameters of any kind. There are C<ev_prepare_set> and C<ev_check_set> |
1745 | macros, but using them is utterly, utterly and completely pointless. |
1768 | macros, but using them is utterly, utterly and completely pointless. |
1746 | |
1769 | |
1747 | =back |
1770 | =back |
1748 | |
1771 | |
|
|
1772 | =head3 Examples |
|
|
1773 | |
1749 | There are a number of principal ways to embed other event loops or modules |
1774 | There are a number of principal ways to embed other event loops or modules |
1750 | into libev. Here are some ideas on how to include libadns into libev |
1775 | into libev. Here are some ideas on how to include libadns into libev |
1751 | (there is a Perl module named C<EV::ADNS> that does this, which you could |
1776 | (there is a Perl module named C<EV::ADNS> that does this, which you could |
1752 | use for an actually working example. Another Perl module named C<EV::Glib> |
1777 | use for an actually working example. Another Perl module named C<EV::Glib> |
1753 | embeds a Glib main context into libev, and finally, C<Glib::EV> embeds EV |
1778 | embeds a Glib main context into libev, and finally, C<Glib::EV> embeds EV |
… | |
… | |
1921 | portable one. |
1946 | portable one. |
1922 | |
1947 | |
1923 | So when you want to use this feature you will always have to be prepared |
1948 | So when you want to use this feature you will always have to be prepared |
1924 | that you cannot get an embeddable loop. The recommended way to get around |
1949 | that you cannot get an embeddable loop. The recommended way to get around |
1925 | this is to have a separate variables for your embeddable loop, try to |
1950 | this is to have a separate variables for your embeddable loop, try to |
1926 | create it, and if that fails, use the normal loop for everything: |
1951 | create it, and if that fails, use the normal loop for everything. |
|
|
1952 | |
|
|
1953 | =head3 Watcher-Specific Functions and Data Members |
|
|
1954 | |
|
|
1955 | =over 4 |
|
|
1956 | |
|
|
1957 | =item ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop) |
|
|
1958 | |
|
|
1959 | =item ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop) |
|
|
1960 | |
|
|
1961 | Configures the watcher to embed the given loop, which must be |
|
|
1962 | embeddable. If the callback is C<0>, then C<ev_embed_sweep> will be |
|
|
1963 | invoked automatically, otherwise it is the responsibility of the callback |
|
|
1964 | to invoke it (it will continue to be called until the sweep has been done, |
|
|
1965 | if you do not want thta, you need to temporarily stop the embed watcher). |
|
|
1966 | |
|
|
1967 | =item ev_embed_sweep (loop, ev_embed *) |
|
|
1968 | |
|
|
1969 | Make a single, non-blocking sweep over the embedded loop. This works |
|
|
1970 | similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most |
|
|
1971 | apropriate way for embedded loops. |
|
|
1972 | |
|
|
1973 | =item struct ev_loop *other [read-only] |
|
|
1974 | |
|
|
1975 | The embedded event loop. |
|
|
1976 | |
|
|
1977 | =back |
|
|
1978 | |
|
|
1979 | =head3 Examples |
|
|
1980 | |
|
|
1981 | Example: Try to get an embeddable event loop and embed it into the default |
|
|
1982 | event loop. If that is not possible, use the default loop. The default |
|
|
1983 | loop is stored in C<loop_hi>, while the mebeddable loop is stored in |
|
|
1984 | C<loop_lo> (which is C<loop_hi> in the acse no embeddable loop can be |
|
|
1985 | used). |
1927 | |
1986 | |
1928 | struct ev_loop *loop_hi = ev_default_init (0); |
1987 | struct ev_loop *loop_hi = ev_default_init (0); |
1929 | struct ev_loop *loop_lo = 0; |
1988 | struct ev_loop *loop_lo = 0; |
1930 | struct ev_embed embed; |
1989 | struct ev_embed embed; |
1931 | |
1990 | |
… | |
… | |
1942 | ev_embed_start (loop_hi, &embed); |
2001 | ev_embed_start (loop_hi, &embed); |
1943 | } |
2002 | } |
1944 | else |
2003 | else |
1945 | loop_lo = loop_hi; |
2004 | loop_lo = loop_hi; |
1946 | |
2005 | |
1947 | =head3 Watcher-Specific Functions and Data Members |
2006 | Example: Check if kqueue is available but not recommended and create |
|
|
2007 | a kqueue backend for use with sockets (which usually work with any |
|
|
2008 | kqueue implementation). Store the kqueue/socket-only event loop in |
|
|
2009 | C<loop_socket>. (One might optionally use C<EVFLAG_NOENV>, too). |
1948 | |
2010 | |
1949 | =over 4 |
2011 | struct ev_loop *loop = ev_default_init (0); |
|
|
2012 | struct ev_loop *loop_socket = 0; |
|
|
2013 | struct ev_embed embed; |
|
|
2014 | |
|
|
2015 | if (ev_supported_backends () & ~ev_recommended_backends () & EVBACKEND_KQUEUE) |
|
|
2016 | if ((loop_socket = ev_loop_new (EVBACKEND_KQUEUE)) |
|
|
2017 | { |
|
|
2018 | ev_embed_init (&embed, 0, loop_socket); |
|
|
2019 | ev_embed_start (loop, &embed); |
|
|
2020 | } |
1950 | |
2021 | |
1951 | =item ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop) |
2022 | if (!loop_socket) |
|
|
2023 | loop_socket = loop; |
1952 | |
2024 | |
1953 | =item ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop) |
2025 | // now use loop_socket for all sockets, and loop for everything else |
1954 | |
|
|
1955 | Configures the watcher to embed the given loop, which must be |
|
|
1956 | embeddable. If the callback is C<0>, then C<ev_embed_sweep> will be |
|
|
1957 | invoked automatically, otherwise it is the responsibility of the callback |
|
|
1958 | to invoke it (it will continue to be called until the sweep has been done, |
|
|
1959 | if you do not want thta, you need to temporarily stop the embed watcher). |
|
|
1960 | |
|
|
1961 | =item ev_embed_sweep (loop, ev_embed *) |
|
|
1962 | |
|
|
1963 | Make a single, non-blocking sweep over the embedded loop. This works |
|
|
1964 | similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most |
|
|
1965 | apropriate way for embedded loops. |
|
|
1966 | |
|
|
1967 | =item struct ev_loop *other [read-only] |
|
|
1968 | |
|
|
1969 | The embedded event loop. |
|
|
1970 | |
|
|
1971 | =back |
|
|
1972 | |
2026 | |
1973 | |
2027 | |
1974 | =head2 C<ev_fork> - the audacity to resume the event loop after a fork |
2028 | =head2 C<ev_fork> - the audacity to resume the event loop after a fork |
1975 | |
2029 | |
1976 | Fork watchers are called when a C<fork ()> was detected (usually because |
2030 | Fork watchers are called when a C<fork ()> was detected (usually because |
… | |
… | |
2455 | wants osf handles on win32 (this is the case when the select to |
2509 | wants osf handles on win32 (this is the case when the select to |
2456 | be used is the winsock select). This means that it will call |
2510 | be used is the winsock select). This means that it will call |
2457 | C<_get_osfhandle> on the fd to convert it to an OS handle. Otherwise, |
2511 | C<_get_osfhandle> on the fd to convert it to an OS handle. Otherwise, |
2458 | it is assumed that all these functions actually work on fds, even |
2512 | it is assumed that all these functions actually work on fds, even |
2459 | on win32. Should not be defined on non-win32 platforms. |
2513 | on win32. Should not be defined on non-win32 platforms. |
|
|
2514 | |
|
|
2515 | =item EV_FD_TO_WIN32_HANDLE |
|
|
2516 | |
|
|
2517 | If C<EV_SELECT_IS_WINSOCKET> is enabled, then libev needs a way to map |
|
|
2518 | file descriptors to socket handles. When not defining this symbol (the |
|
|
2519 | default), then libev will call C<_get_osfhandle>, which is usually |
|
|
2520 | correct. In some cases, programs use their own file descriptor management, |
|
|
2521 | in which case they can provide this function to map fds to socket handles. |
2460 | |
2522 | |
2461 | =item EV_USE_POLL |
2523 | =item EV_USE_POLL |
2462 | |
2524 | |
2463 | If defined to be C<1>, libev will compile in support for the C<poll>(2) |
2525 | If defined to be C<1>, libev will compile in support for the C<poll>(2) |
2464 | backend. Otherwise it will be enabled on non-win32 platforms. It |
2526 | backend. Otherwise it will be enabled on non-win32 platforms. It |
… | |
… | |
2501 | be detected at runtime. |
2563 | be detected at runtime. |
2502 | |
2564 | |
2503 | =item EV_H |
2565 | =item EV_H |
2504 | |
2566 | |
2505 | The name of the F<ev.h> header file used to include it. The default if |
2567 | The name of the F<ev.h> header file used to include it. The default if |
2506 | undefined is C<< <ev.h> >> in F<event.h> and C<"ev.h"> in F<ev.c>. This |
2568 | undefined is C<"ev.h"> in F<event.h>, F<ev.c> and F<ev++.h>. This can be |
2507 | can be used to virtually rename the F<ev.h> header file in case of conflicts. |
2569 | used to virtually rename the F<ev.h> header file in case of conflicts. |
2508 | |
2570 | |
2509 | =item EV_CONFIG_H |
2571 | =item EV_CONFIG_H |
2510 | |
2572 | |
2511 | If C<EV_STANDALONE> isn't C<1>, this variable can be used to override |
2573 | If C<EV_STANDALONE> isn't C<1>, this variable can be used to override |
2512 | F<ev.c>'s idea of where to find the F<config.h> file, similarly to |
2574 | F<ev.c>'s idea of where to find the F<config.h> file, similarly to |
2513 | C<EV_H>, above. |
2575 | C<EV_H>, above. |
2514 | |
2576 | |
2515 | =item EV_EVENT_H |
2577 | =item EV_EVENT_H |
2516 | |
2578 | |
2517 | Similarly to C<EV_H>, this macro can be used to override F<event.c>'s idea |
2579 | Similarly to C<EV_H>, this macro can be used to override F<event.c>'s idea |
2518 | of how the F<event.h> header can be found. |
2580 | of how the F<event.h> header can be found, the default is C<"event.h">. |
2519 | |
2581 | |
2520 | =item EV_PROTOTYPES |
2582 | =item EV_PROTOTYPES |
2521 | |
2583 | |
2522 | If defined to be C<0>, then F<ev.h> will not define any function |
2584 | If defined to be C<0>, then F<ev.h> will not define any function |
2523 | prototypes, but still define all the structs and other symbols. This is |
2585 | prototypes, but still define all the structs and other symbols. This is |
… | |
… | |
2737 | watchers becomes O(1) w.r.t. prioritiy handling. |
2799 | watchers becomes O(1) w.r.t. prioritiy handling. |
2738 | |
2800 | |
2739 | =back |
2801 | =back |
2740 | |
2802 | |
2741 | |
2803 | |
|
|
2804 | =head1 Win32 platform limitations and workarounds |
|
|
2805 | |
|
|
2806 | Win32 doesn't support any of the standards (e.g. POSIX) that libev |
|
|
2807 | requires, and its I/O model is fundamentally incompatible with the POSIX |
|
|
2808 | model. Libev still offers limited functionality on this platform in |
|
|
2809 | the form of the C<EVBACKEND_SELECT> backend, and only supports socket |
|
|
2810 | descriptors. This only applies when using Win32 natively, not when using |
|
|
2811 | e.g. cygwin. |
|
|
2812 | |
|
|
2813 | There is no supported compilation method available on windows except |
|
|
2814 | embedding it into other applications. |
|
|
2815 | |
|
|
2816 | Due to the many, low, and arbitrary limits on the win32 platform and the |
|
|
2817 | abysmal performance of winsockets, using a large number of sockets is not |
|
|
2818 | recommended (and not reasonable). If your program needs to use more than |
|
|
2819 | a hundred or so sockets, then likely it needs to use a totally different |
|
|
2820 | implementation for windows, as libev offers the POSIX model, which cannot |
|
|
2821 | be implemented efficiently on windows (microsoft monopoly games). |
|
|
2822 | |
|
|
2823 | =over 4 |
|
|
2824 | |
|
|
2825 | =item The winsocket select function |
|
|
2826 | |
|
|
2827 | The winsocket C<select> function doesn't follow POSIX in that it requires |
|
|
2828 | socket I<handles> and not socket I<file descriptors>. This makes select |
|
|
2829 | very inefficient, and also requires a mapping from file descriptors |
|
|
2830 | to socket handles. See the discussion of the C<EV_SELECT_USE_FD_SET>, |
|
|
2831 | C<EV_SELECT_IS_WINSOCKET> and C<EV_FD_TO_WIN32_HANDLE> preprocessor |
|
|
2832 | symbols for more info. |
|
|
2833 | |
|
|
2834 | The configuration for a "naked" win32 using the microsoft runtime |
|
|
2835 | libraries and raw winsocket select is: |
|
|
2836 | |
|
|
2837 | #define EV_USE_SELECT 1 |
|
|
2838 | #define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */ |
|
|
2839 | |
|
|
2840 | Note that winsockets handling of fd sets is O(n), so you can easily get a |
|
|
2841 | complexity in the O(n²) range when using win32. |
|
|
2842 | |
|
|
2843 | =item Limited number of file descriptors |
|
|
2844 | |
|
|
2845 | Windows has numerous arbitrary (and low) limits on things. Early versions |
|
|
2846 | of winsocket's select only supported waiting for a max. of C<64> handles |
|
|
2847 | (probably owning to the fact that all windows kernels can only wait for |
|
|
2848 | C<64> things at the same time internally; microsoft recommends spawning a |
|
|
2849 | chain of threads and wait for 63 handles and the previous thread in each). |
|
|
2850 | |
|
|
2851 | Newer versions support more handles, but you need to define C<FD_SETSIZE> |
|
|
2852 | to some high number (e.g. C<2048>) before compiling the winsocket select |
|
|
2853 | call (which might be in libev or elsewhere, for example, perl does its own |
|
|
2854 | select emulation on windows). |
|
|
2855 | |
|
|
2856 | Another limit is the number of file descriptors in the microsoft runtime |
|
|
2857 | libraries, which by default is C<64> (there must be a hidden I<64> fetish |
|
|
2858 | or something like this inside microsoft). You can increase this by calling |
|
|
2859 | C<_setmaxstdio>, which can increase this limit to C<2048> (another |
|
|
2860 | arbitrary limit), but is broken in many versions of the microsoft runtime |
|
|
2861 | libraries. |
|
|
2862 | |
|
|
2863 | This might get you to about C<512> or C<2048> sockets (depending on |
|
|
2864 | windows version and/or the phase of the moon). To get more, you need to |
|
|
2865 | wrap all I/O functions and provide your own fd management, but the cost of |
|
|
2866 | calling select (O(n²)) will likely make this unworkable. |
|
|
2867 | |
|
|
2868 | =back |
|
|
2869 | |
|
|
2870 | |
2742 | =head1 AUTHOR |
2871 | =head1 AUTHOR |
2743 | |
2872 | |
2744 | Marc Lehmann <libev@schmorp.de>. |
2873 | Marc Lehmann <libev@schmorp.de>. |
2745 | |
2874 | |