… | |
… | |
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; |
… | |
… | |
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 | |
… | |
… | |
2491 | 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 |
2492 | 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, |
2493 | 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 |
2494 | on win32. Should not be defined on non-win32 platforms. |
2513 | on win32. Should not be defined on non-win32 platforms. |
2495 | |
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. |
|
|
2522 | |
2496 | =item EV_USE_POLL |
2523 | =item EV_USE_POLL |
2497 | |
2524 | |
2498 | 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) |
2499 | backend. Otherwise it will be enabled on non-win32 platforms. It |
2526 | backend. Otherwise it will be enabled on non-win32 platforms. It |
2500 | takes precedence over select. |
2527 | takes precedence over select. |
… | |
… | |
2536 | be detected at runtime. |
2563 | be detected at runtime. |
2537 | |
2564 | |
2538 | =item EV_H |
2565 | =item EV_H |
2539 | |
2566 | |
2540 | 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 |
2541 | undefined is C<"ev.h"> in F<event.h> and F<ev.c>. This can be used to |
2568 | undefined is C<"ev.h"> in F<event.h>, F<ev.c> and F<ev++.h>. This can be |
2542 | 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. |
2543 | |
2570 | |
2544 | =item EV_CONFIG_H |
2571 | =item EV_CONFIG_H |
2545 | |
2572 | |
2546 | 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 |
2547 | 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 |
2548 | C<EV_H>, above. |
2575 | C<EV_H>, above. |
2549 | |
2576 | |
2550 | =item EV_EVENT_H |
2577 | =item EV_EVENT_H |
2551 | |
2578 | |
2552 | 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 |
2553 | of how the F<event.h> header can be found, the dfeault is C<"event.h">. |
2580 | of how the F<event.h> header can be found, the default is C<"event.h">. |
2554 | |
2581 | |
2555 | =item EV_PROTOTYPES |
2582 | =item EV_PROTOTYPES |
2556 | |
2583 | |
2557 | 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 |
2558 | 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 |
… | |
… | |
2772 | watchers becomes O(1) w.r.t. prioritiy handling. |
2799 | watchers becomes O(1) w.r.t. prioritiy handling. |
2773 | |
2800 | |
2774 | =back |
2801 | =back |
2775 | |
2802 | |
2776 | |
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 | |
2777 | =head1 AUTHOR |
2871 | =head1 AUTHOR |
2778 | |
2872 | |
2779 | Marc Lehmann <libev@schmorp.de>. |
2873 | Marc Lehmann <libev@schmorp.de>. |
2780 | |
2874 | |