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Revision 1.236 by root, Thu Apr 16 07:56:05 2009 UTC vs.
Revision 1.238 by root, Sat Apr 18 12:10:41 2009 UTC

… …
122name C<loop> (which is always of type C<ev_loop *>) will not have 122name C<loop> (which is always of type C<ev_loop *>) will not have
123this argument. 123this argument.
124 124
125=head2 TIME REPRESENTATION 125=head2 TIME REPRESENTATION
126 126
127Libev represents time as a single floating point number, representing the 127Libev represents time as a single floating point number, representing
128(fractional) number of seconds since the (POSIX) epoch (somewhere near 128the (fractional) number of seconds since the (POSIX) epoch (somewhere
129the beginning of 1970, details are complicated, don't ask). This type is 129near the beginning of 1970, details are complicated, don't ask). This
130called C<ev_tstamp>, which is what you should use too. It usually aliases 130type is called C<ev_tstamp>, which is what you should use too. It usually
131to the C<double> type in C, and when you need to do any calculations on 131aliases to the C<double> type in C. When you need to do any calculations
132it, you should treat it as some floating point value. Unlike the name 132on it, you should treat it as some floating point value. Unlike the name
133component C<stamp> might indicate, it is also used for time differences 133component C<stamp> might indicate, it is also used for time differences
134throughout libev. 134throughout libev.
135 135
136=head1 ERROR HANDLING 136=head1 ERROR HANDLING
137 137
… …
644 644
645This function is rarely useful, but when some event callback runs for a 645This function is rarely useful, but when some event callback runs for a
646very long time without entering the event loop, updating libev's idea of 646very long time without entering the event loop, updating libev's idea of
647the current time is a good idea. 647the current time is a good idea.
648 648
649See also "The special problem of time updates" in the C<ev_timer> section. 649See also L<The special problem of time updates> in the C<ev_timer> section.
650 650
651=item ev_suspend (loop) 651=item ev_suspend (loop)
652 652
653=item ev_resume (loop) 653=item ev_resume (loop)
654 654
… …
2708event loop blocks next and before C<ev_check> watchers are being called, 2708event loop blocks next and before C<ev_check> watchers are being called,
2709and only in the child after the fork. If whoever good citizen calling 2709and only in the child after the fork. If whoever good citizen calling
2710C<ev_default_fork> cheats and calls it in the wrong process, the fork 2710C<ev_default_fork> cheats and calls it in the wrong process, the fork
2711handlers will be invoked, too, of course. 2711handlers will be invoked, too, of course.
2712 2712
2713=head3 The special problem of life after fork - how is it possible?
2714
2715Most uses of C<fork()> consist of forking, then some simple calls to ste
2716up/change the process environment, followed by a call to C<exec()>. This
2717sequence should be handled by libev without any problems.
2718
2719This changes when the application actually wants to do event handling
2720in the child, or both parent in child, in effect "continuing" after the
2721fork.
2722
2723The default mode of operation (for libev, with application help to detect
2724forks) is to duplicate all the state in the child, as would be expected
2725when I<either> the parent I<or> the child process continues.
2726
2727When both processes want to continue using libev, then this is usually the
2728wrong result. In that case, usually one process (typically the parent) is
2729supposed to continue with all watchers in place as before, while the other
2730process typically wants to start fresh, i.e. without any active watchers.
2731
2732The cleanest and most efficient way to achieve that with libev is to
2733simply create a new event loop, which of course will be "empty", and
2734use that for new watchers. This has the advantage of not touching more
2735memory than necessary, and thus avoiding the copy-on-write, and the
2736disadvantage of having to use multiple event loops (which do not support
2737signal watchers).
2738
2739When this is not possible, or you want to use the default loop for
2740other reasons, then in the process that wants to start "fresh", call
2741C<ev_default_destroy ()> followed by C<ev_default_loop (...)>. Destroying
2742the default loop will "orphan" (not stop) all registered watchers, so you
2743have to be careful not to execute code that modifies those watchers. Note
2744also that in that case, you have to re-register any signal watchers.
2745
2713=head3 Watcher-Specific Functions and Data Members 2746=head3 Watcher-Specific Functions and Data Members
2714 2747
2715=over 4 2748=over 4
2716 2749
2717=item ev_fork_init (ev_signal *, callback) 2750=item ev_fork_init (ev_signal *, callback)

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