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Revision 1.112 by root, Wed Dec 26 08:06:09 2007 UTC vs.
Revision 1.118 by root, Thu Jan 10 06:00:55 2008 UTC

260flags. If that is troubling you, check C<ev_backend ()> afterwards). 260flags. If that is troubling you, check C<ev_backend ()> afterwards).
261 261
262If you don't know what event loop to use, use the one returned from this 262If you don't know what event loop to use, use the one returned from this
263function. 263function.
264 264
265The default loop is the only loop that can handle C<ev_signal> and
266C<ev_child> watchers, and to do this, it always registers a handler
267for C<SIGCHLD>. If this is a problem for your app you can either
268create a dynamic loop with C<ev_loop_new> that doesn't do that, or you
269can simply overwrite the C<SIGCHLD> signal handler I<after> calling
270C<ev_default_init>.
271
265The flags argument can be used to specify special behaviour or specific 272The flags argument can be used to specify special behaviour or specific
266backends to use, and is usually specified as C<0> (or C<EVFLAG_AUTO>). 273backends to use, and is usually specified as C<0> (or C<EVFLAG_AUTO>).
267 274
268The following flags are supported: 275The following flags are supported:
269 276
403While this backend scales well, it requires one system call per active 410While this backend scales well, it requires one system call per active
404file descriptor per loop iteration. For small and medium numbers of file 411file descriptor per loop iteration. For small and medium numbers of file
405descriptors a "slow" C<EVBACKEND_SELECT> or C<EVBACKEND_POLL> backend 412descriptors a "slow" C<EVBACKEND_SELECT> or C<EVBACKEND_POLL> backend
406might perform better. 413might perform better.
407 414
415On the positive side, ignoring the spurious readyness notifications, this
416backend actually performed to specification in all tests and is fully
417embeddable, which is a rare feat among the OS-specific backends.
418
408=item C<EVBACKEND_ALL> 419=item C<EVBACKEND_ALL>
409 420
410Try all backends (even potentially broken ones that wouldn't be tried 421Try all backends (even potentially broken ones that wouldn't be tried
411with C<EVFLAG_AUTO>). Since this is a mask, you can do stuff such as 422with C<EVFLAG_AUTO>). Since this is a mask, you can do stuff such as
412C<EVBACKEND_ALL & ~EVBACKEND_KQUEUE>. 423C<EVBACKEND_ALL & ~EVBACKEND_KQUEUE>.
414It is definitely not recommended to use this flag. 425It is definitely not recommended to use this flag.
415 426
416=back 427=back
417 428
418If one or more of these are ored into the flags value, then only these 429If one or more of these are ored into the flags value, then only these
419backends will be tried (in the reverse order as given here). If none are 430backends will be tried (in the reverse order as listed here). If none are
420specified, most compiled-in backend will be tried, usually in reverse 431specified, all backends in C<ev_recommended_backends ()> will be tried.
421order of their flag values :)
422 432
423The most typical usage is like this: 433The 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?");
551usually a better approach for this kind of thing. 561usually a better approach for this kind of thing.
552 562
553Here are the gory details of what C<ev_loop> does: 563Here are the gory details of what C<ev_loop> does:
554 564
555 - Before the first iteration, call any pending watchers. 565 - Before the first iteration, call any pending watchers.
556 * If there are no active watchers (reference count is zero), return. 566 * If EVFLAG_FORKCHECK was used, check for a fork.
557 - Queue all prepare watchers and then call all outstanding watchers. 567 - If a fork was detected, queue and call all fork watchers.
568 - Queue and call all prepare watchers.
558 - If we have been forked, recreate the kernel state. 569 - If we have been forked, recreate the kernel state.
559 - Update the kernel state with all outstanding changes. 570 - Update the kernel state with all outstanding changes.
560 - Update the "event loop time". 571 - Update the "event loop time".
561 - Calculate for how long to block. 572 - Calculate for how long to sleep or block, if at all
573 (active idle watchers, EVLOOP_NONBLOCK or not having
574 any active watchers at all will result in not sleeping).
575 - Sleep if the I/O and timer collect interval say so.
562 - Block the process, waiting for any events. 576 - Block the process, waiting for any events.
563 - Queue all outstanding I/O (fd) events. 577 - Queue all outstanding I/O (fd) events.
564 - Update the "event loop time" and do time jump handling. 578 - Update the "event loop time" and do time jump handling.
565 - Queue all outstanding timers. 579 - Queue all outstanding timers.
566 - Queue all outstanding periodics. 580 - Queue all outstanding periodics.
567 - If no events are pending now, queue all idle watchers. 581 - If no events are pending now, queue all idle watchers.
568 - Queue all check watchers. 582 - Queue all check watchers.
569 - Call all queued watchers in reverse order (i.e. check watchers first). 583 - 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 584 Signals and child watchers are implemented as I/O watchers, and will
571 be handled here by queueing them when their watcher gets executed. 585 be handled here by queueing them when their watcher gets executed.
572 - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK 586 - If ev_unloop has been called, or EVLOOP_ONESHOT or EVLOOP_NONBLOCK
573 were used, return, otherwise continue with step *. 587 were used, or there are no active watchers, return, otherwise
588 continue with step *.
574 589
575Example: Queue some jobs and then loop until no events are outsanding 590Example: Queue some jobs and then loop until no events are outstanding
576anymore. 591anymore.
577 592
578 ... queue jobs here, make sure they register event watchers as long 593 ... 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..) 594 ... as they still have work to do (even an idle watcher will do..)
580 ev_loop (my_loop, 0); 595 ev_loop (my_loop, 0);
584 599
585Can be used to make a call to C<ev_loop> return early (but only after it 600Can be used to make a call to C<ev_loop> return early (but only after it
586has processed all outstanding events). The C<how> argument must be either 601has processed all outstanding events). The C<how> argument must be either
587C<EVUNLOOP_ONE>, which will make the innermost C<ev_loop> call return, or 602C<EVUNLOOP_ONE>, which will make the innermost C<ev_loop> call return, or
588C<EVUNLOOP_ALL>, which will make all nested C<ev_loop> calls return. 603C<EVUNLOOP_ALL>, which will make all nested C<ev_loop> calls return.
604
605This "unloop state" will be cleared when entering C<ev_loop> again.
589 606
590=item ev_ref (loop) 607=item ev_ref (loop)
591 608
592=item ev_unref (loop) 609=item ev_unref (loop)
593 610
598returning, ev_unref() after starting, and ev_ref() before stopping it. For 615returning, ev_unref() after starting, and ev_ref() before stopping it. For
599example, libev itself uses this for its internal signal pipe: It is not 616example, libev itself uses this for its internal signal pipe: It is not
600visible to the libev user and should not keep C<ev_loop> from exiting if 617visible to the libev user and should not keep C<ev_loop> from exiting if
601no event watchers registered by it are active. It is also an excellent 618no event watchers registered by it are active. It is also an excellent
602way to do this for generic recurring timers or from within third-party 619way to do this for generic recurring timers or from within third-party
603libraries. Just remember to I<unref after start> and I<ref before stop>. 620libraries. Just remember to I<unref after start> and I<ref before stop>
621(but only if the watcher wasn't active before, or was active before,
622respectively).
604 623
605Example: Create a signal watcher, but keep it from keeping C<ev_loop> 624Example: Create a signal watcher, but keep it from keeping C<ev_loop>
606running when nothing else is active. 625running when nothing else is active.
607 626
608 struct ev_signal exitsig; 627 struct ev_signal exitsig;
2544be detected at runtime. 2563be detected at runtime.
2545 2564
2546=item EV_H 2565=item EV_H
2547 2566
2548The name of the F<ev.h> header file used to include it. The default if 2567The name of the F<ev.h> header file used to include it. The default if
2549undefined is C<"ev.h"> in F<event.h> and F<ev.c>. This can be used to 2568undefined is C<"ev.h"> in F<event.h>, F<ev.c> and F<ev++.h>. This can be
2550virtually rename the F<ev.h> header file in case of conflicts. 2569used to virtually rename the F<ev.h> header file in case of conflicts.
2551 2570
2552=item EV_CONFIG_H 2571=item EV_CONFIG_H
2553 2572
2554If C<EV_STANDALONE> isn't C<1>, this variable can be used to override 2573If C<EV_STANDALONE> isn't C<1>, this variable can be used to override
2555F<ev.c>'s idea of where to find the F<config.h> file, similarly to 2574F<ev.c>'s idea of where to find the F<config.h> file, similarly to
2556C<EV_H>, above. 2575C<EV_H>, above.
2557 2576
2558=item EV_EVENT_H 2577=item EV_EVENT_H
2559 2578
2560Similarly to C<EV_H>, this macro can be used to override F<event.c>'s idea 2579Similarly to C<EV_H>, this macro can be used to override F<event.c>'s idea
2561of how the F<event.h> header can be found, the dfeault is C<"event.h">. 2580of how the F<event.h> header can be found, the default is C<"event.h">.
2562 2581
2563=item EV_PROTOTYPES 2582=item EV_PROTOTYPES
2564 2583
2565If defined to be C<0>, then F<ev.h> will not define any function 2584If defined to be C<0>, then F<ev.h> will not define any function
2566prototypes, but still define all the structs and other symbols. This is 2585prototypes, but still define all the structs and other symbols. This is

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