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Comparing libev/ev.pod (file contents):
Revision 1.290 by root, Tue Mar 16 18:03:01 2010 UTC vs.
Revision 1.291 by root, Tue Mar 16 20:32:20 2010 UTC

345useful to try out specific backends to test their performance, or to work 345useful to try out specific backends to test their performance, or to work
346around bugs. 346around bugs.
347 347
348=item C<EVFLAG_FORKCHECK> 348=item C<EVFLAG_FORKCHECK>
349 349
350Instead of calling C<ev_default_fork> or C<ev_loop_fork> manually after 350Instead of calling C<ev_loop_fork> manually after a fork, you can also
351a fork, you can also make libev check for a fork in each iteration by 351make libev check for a fork in each iteration by enabling this flag.
352enabling this flag.
353 352
354This works by calling C<getpid ()> on every iteration of the loop, 353This works by calling C<getpid ()> on every iteration of the loop,
355and thus this might slow down your event loop if you do a lot of loop 354and thus this might slow down your event loop if you do a lot of loop
356iterations and little real work, but is usually not noticeable (on my 355iterations and little real work, but is usually not noticeable (on my
357GNU/Linux system for example, C<getpid> is actually a simple 5-insn sequence 356GNU/Linux system for example, C<getpid> is actually a simple 5-insn sequence
611name, you can call it anytime, but it makes most sense after forking, in 610name, you can call it anytime, but it makes most sense after forking, in
612the child process (or both child and parent, but that again makes little 611the child process (or both child and parent, but that again makes little
613sense). You I<must> call it in the child before using any of the libev 612sense). You I<must> call it in the child before using any of the libev
614functions, and it will only take effect at the next C<ev_loop> iteration. 613functions, and it will only take effect at the next C<ev_loop> iteration.
615 614
615Again, you I<have> to call it on I<any> loop that you want to re-use after
616a fork, I<even if you do not plan to use the loop in the parent>. This is
617because some kernel interfaces *cough* I<kqueue> *cough* do funny things
618during fork.
619
616On the other hand, you only need to call this function in the child 620On the other hand, you only need to call this function in the child
617process if and only if you want to use the event library in the child. If 621process if and only if you want to use the event loop in the child. If you
618you just fork+exec, you don't have to call it at all. 622just fork+exec or create a new loop in the child, you don't have to call
623it at all.
619 624
620The function itself is quite fast and it's usually not a problem to call 625The function itself is quite fast and it's usually not a problem to call
621it just in case after a fork. To make this easy, the function will fit in 626it just in case after a fork. To make this easy, the function will fit in
622quite nicely into a call to C<pthread_atfork>: 627quite nicely into a call to C<pthread_atfork>:
623 628
625 630
626=item ev_loop_fork (loop) 631=item ev_loop_fork (loop)
627 632
628Like C<ev_default_fork>, but acts on an event loop created by 633Like C<ev_default_fork>, but acts on an event loop created by
629C<ev_loop_new>. Yes, you have to call this on every allocated event loop 634C<ev_loop_new>. Yes, you have to call this on every allocated event loop
630after fork that you want to re-use in the child, and how you do this is 635after fork that you want to re-use in the child, and how you keep track of
631entirely your own problem. 636them is entirely your own problem.
632 637
633=item int ev_is_default_loop (loop) 638=item int ev_is_default_loop (loop)
634 639
635Returns true when the given loop is, in fact, the default loop, and false 640Returns true when the given loop is, in fact, the default loop, and false
636otherwise. 641otherwise.
637 642
638=item unsigned int ev_loop_count (loop) 643=item unsigned int ev_iteration (loop)
639 644
640Returns the count of loop iterations for the loop, which is identical to 645Returns the current iteration count for the loop, which is identical to
641the number of times libev did poll for new events. It starts at C<0> and 646the number of times libev did poll for new events. It starts at C<0> and
642happily wraps around with enough iterations. 647happily wraps around with enough iterations.
643 648
644This value can sometimes be useful as a generation counter of sorts (it 649This value can sometimes be useful as a generation counter of sorts (it
645"ticks" the number of loop iterations), as it roughly corresponds with 650"ticks" the number of loop iterations), as it roughly corresponds with
646C<ev_prepare> and C<ev_check> calls. 651C<ev_prepare> and C<ev_check> calls - and is incremented between the
652prepare and check phases.
647 653
648=item unsigned int ev_loop_depth (loop) 654=item unsigned int ev_depth (loop)
649 655
650Returns the number of times C<ev_loop> was entered minus the number of 656Returns the number of times C<ev_loop> was entered minus the number of
651times C<ev_loop> was exited, in other words, the recursion depth. 657times C<ev_loop> was exited, in other words, the recursion depth.
652 658
653Outside C<ev_loop>, this number is zero. In a callback, this number is 659Outside C<ev_loop>, this number is zero. In a callback, this number is
654C<1>, unless C<ev_loop> was invoked recursively (or from another thread), 660C<1>, unless C<ev_loop> was invoked recursively (or from another thread),
655in which case it is higher. 661in which case it is higher.
656 662
657Leaving C<ev_loop> abnormally (setjmp/longjmp, cancelling the thread 663Leaving C<ev_loop> abnormally (setjmp/longjmp, cancelling the thread
658etc.), doesn't count as exit. 664etc.), doesn't count as "exit" - consider this as a hint to avoid such
665ungentleman behaviour unless it's really convenient.
659 666
660=item unsigned int ev_backend (loop) 667=item unsigned int ev_backend (loop)
661 668
662Returns one of the C<EVBACKEND_*> flags indicating the event backend in 669Returns one of the C<EVBACKEND_*> flags indicating the event backend in
663use. 670use.
4618involves iterating over all running async watchers or all signal numbers. 4625involves iterating over all running async watchers or all signal numbers.
4619 4626
4620=back 4627=back
4621 4628
4622 4629
4623=head1 PORTING FROM 3.X TO 4.X 4630=head1 PORTING FROM LIBEV 3.X TO 4.X
4624 4631
4625The major version 4 introduced some minor incompatible changes to the API. 4632The major version 4 introduced some minor incompatible changes to the API.
4626 4633
4634At the moment, the C<ev.h> header file tries to implement superficial
4635compatibility, so most programs should still compile. Those might be
4636removed in later versions of libev, so better update early than late.
4637
4627=over 4 4638=over 4
4628 4639
4640=item C<ev_loop_count> renamed to C<ev_iteration>
4641
4642=item C<ev_loop_depth> renamed to C<ev_depth>
4643
4644=item C<ev_loop_verify> renamed to C<ev_verify>
4645
4646Most functions working on C<struct ev_loop> objects don't have an
4647C<ev_loop_> prefix, so it was removed. Note that C<ev_loop_fork> is
4648still called C<ev_loop_fork> because it would otherwise clash with the
4649C<ev_frok> typedef.
4650
4629=item C<EV_TIMEOUT> replaced by C<EV_TIMER> in C<revents> 4651=item C<EV_TIMEOUT> renamed to C<EV_TIMER> in C<revents>
4630 4652
4631This is a simple rename - all other watcher types use their name 4653This is a simple rename - all other watcher types use their name
4632as revents flag, and now C<ev_timer> does, too. 4654as revents flag, and now C<ev_timer> does, too.
4633 4655
4634Both C<EV_TIMER> and C<EV_TIMEOUT> symbols were present in 3.x versions 4656Both C<EV_TIMER> and C<EV_TIMEOUT> symbols were present in 3.x versions

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