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Revision 1.371 by root, Sat Jun 4 05:25:03 2011 UTC vs.
Revision 1.374 by sf-exg, Sat Jun 4 16:54:59 2011 UTC

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441example) that can't properly initialise their signal masks. 441example) that can't properly initialise their signal masks.
442 442
443=item C<EVFLAG_NOSIGMASK> 443=item C<EVFLAG_NOSIGMASK>
444 444
445When this flag is specified, then libev will avoid to modify the signal 445When this flag is specified, then libev will avoid to modify the signal
446mask. Specifically, this means you ahve to make sure signals are unblocked 446mask. Specifically, this means you have to make sure signals are unblocked
447when you want to receive them. 447when you want to receive them.
448 448
449This behaviour is useful when you want to do your own signal handling, or 449This behaviour is useful when you want to do your own signal handling, or
450want to handle signals only in specific threads and want to avoid libev 450want to handle signals only in specific threads and want to avoid libev
451unblocking the signals. 451unblocking the signals.
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512totally I<different> file descriptors (even already closed ones, so 512totally I<different> file descriptors (even already closed ones, so
513one cannot even remove them from the set) than registered in the set 513one cannot even remove them from the set) than registered in the set
514(especially on SMP systems). Libev tries to counter these spurious 514(especially on SMP systems). Libev tries to counter these spurious
515notifications by employing an additional generation counter and comparing 515notifications by employing an additional generation counter and comparing
516that against the events to filter out spurious ones, recreating the set 516that against the events to filter out spurious ones, recreating the set
517when required. Epoll also errornously rounds down timeouts, but gives you 517when required. Epoll also erroneously rounds down timeouts, but gives you
518no way to know when and by how much, so sometimes you have to busy-wait 518no way to know when and by how much, so sometimes you have to busy-wait
519because epoll returns immediately despite a nonzero timeout. And last 519because epoll returns immediately despite a nonzero timeout. And last
520not least, it also refuses to work with some file descriptors which work 520not least, it also refuses to work with some file descriptors which work
521perfectly fine with C<select> (files, many character devices...). 521perfectly fine with C<select> (files, many character devices...).
522 522
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952overhead for the actual polling but can deliver many events at once. 952overhead for the actual polling but can deliver many events at once.
953 953
954By setting a higher I<io collect interval> you allow libev to spend more 954By setting a higher I<io collect interval> you allow libev to spend more
955time collecting I/O events, so you can handle more events per iteration, 955time collecting I/O events, so you can handle more events per iteration,
956at the cost of increasing latency. Timeouts (both C<ev_periodic> and 956at the cost of increasing latency. Timeouts (both C<ev_periodic> and
957C<ev_timer>) will be not affected. Setting this to a non-null value will 957C<ev_timer>) will not be affected. Setting this to a non-null value will
958introduce an additional C<ev_sleep ()> call into most loop iterations. The 958introduce an additional C<ev_sleep ()> call into most loop iterations. The
959sleep time ensures that libev will not poll for I/O events more often then 959sleep time ensures that libev will not poll for I/O events more often then
960once per this interval, on average. 960once per this interval, on average (as long as the host time resolution is
961good enough).
961 962
962Likewise, by setting a higher I<timeout collect interval> you allow libev 963Likewise, by setting a higher I<timeout collect interval> you allow libev
963to spend more time collecting timeouts, at the expense of increased 964to spend more time collecting timeouts, at the expense of increased
964latency/jitter/inexactness (the watcher callback will be called 965latency/jitter/inexactness (the watcher callback will be called
965later). C<ev_io> watchers will not be affected. Setting this to a non-null 966later). C<ev_io> watchers will not be affected. Setting this to a non-null
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1385 1386
1386=over 4 1387=over 4
1387 1388
1388=item initialiased 1389=item initialiased
1389 1390
1390Before a watcher can be registered with the event looop it has to be 1391Before a watcher can be registered with the event loop it has to be
1391initialised. This can be done with a call to C<ev_TYPE_init>, or calls to 1392initialised. This can be done with a call to C<ev_TYPE_init>, or calls to
1392C<ev_init> followed by the watcher-specific C<ev_TYPE_set> function. 1393C<ev_init> followed by the watcher-specific C<ev_TYPE_set> function.
1393 1394
1394In this state it is simply some block of memory that is suitable for 1395In this state it is simply some block of memory that is suitable for
1395use in an event loop. It can be moved around, freed, reused etc. at 1396use in an event loop. It can be moved around, freed, reused etc. at
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4903requires, and its I/O model is fundamentally incompatible with the POSIX 4904requires, and its I/O model is fundamentally incompatible with the POSIX
4904model. Libev still offers limited functionality on this platform in 4905model. Libev still offers limited functionality on this platform in
4905the form of the C<EVBACKEND_SELECT> backend, and only supports socket 4906the form of the C<EVBACKEND_SELECT> backend, and only supports socket
4906descriptors. This only applies when using Win32 natively, not when using 4907descriptors. This only applies when using Win32 natively, not when using
4907e.g. cygwin. Actually, it only applies to the microsofts own compilers, 4908e.g. cygwin. Actually, it only applies to the microsofts own compilers,
4908as every compielr comes with a slightly differently broken/incompatible 4909as every compiler comes with a slightly differently broken/incompatible
4909environment. 4910environment.
4910 4911
4911Lifting these limitations would basically require the full 4912Lifting these limitations would basically require the full
4912re-implementation of the I/O system. If you are into this kind of thing, 4913re-implementation of the I/O system. If you are into this kind of thing,
4913then note that glib does exactly that for you in a very portable way (note 4914then note that glib does exactly that for you in a very portable way (note

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