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Comparing libev/ev.pod (file contents):
Revision 1.301 by root, Fri Sep 10 05:38:38 2010 UTC vs.
Revision 1.302 by root, Thu Oct 14 04:23:19 2010 UTC

… …
2965C<ev_default_fork> cheats and calls it in the wrong process, the fork 2965C<ev_default_fork> cheats and calls it in the wrong process, the fork
2966handlers will be invoked, too, of course. 2966handlers will be invoked, too, of course.
2967 2967
2968=head3 The special problem of life after fork - how is it possible? 2968=head3 The special problem of life after fork - how is it possible?
2969 2969
2970Most uses of C<fork()> consist of forking, then some simple calls to ste 2970Most uses of C<fork()> consist of forking, then some simple calls to set
2971up/change the process environment, followed by a call to C<exec()>. This 2971up/change the process environment, followed by a call to C<exec()>. This
2972sequence should be handled by libev without any problems. 2972sequence should be handled by libev without any problems.
2973 2973
2974This changes when the application actually wants to do event handling 2974This changes when the application actually wants to do event handling
2975in the child, or both parent in child, in effect "continuing" after the 2975in the child, or both parent in child, in effect "continuing" after the
… …
3009believe me. 3009believe me.
3010 3010
3011=back 3011=back
3012 3012
3013 3013
3014=head2 C<ev_async> - how to wake up another event loop 3014=head2 C<ev_async> - how to wake up an event loop
3015 3015
3016In general, you cannot use an C<ev_loop> from multiple threads or other 3016In general, you cannot use an C<ev_loop> from multiple threads or other
3017asynchronous sources such as signal handlers (as opposed to multiple event 3017asynchronous sources such as signal handlers (as opposed to multiple event
3018loops - those are of course safe to use in different threads). 3018loops - those are of course safe to use in different threads).
3019 3019
3020Sometimes, however, you need to wake up another event loop you do not 3020Sometimes, however, you need to wake up an event loop you do not control,
3021control, for example because it belongs to another thread. This is what 3021for example because it belongs to another thread. This is what C<ev_async>
3022C<ev_async> watchers do: as long as the C<ev_async> watcher is active, you 3022watchers do: as long as the C<ev_async> watcher is active, you can signal
3023can signal it by calling C<ev_async_send>, which is thread- and signal 3023it by calling C<ev_async_send>, which is thread- and signal safe.
3024safe.
3025 3024
3026This functionality is very similar to C<ev_signal> watchers, as signals, 3025This functionality is very similar to C<ev_signal> watchers, as signals,
3027too, are asynchronous in nature, and signals, too, will be compressed 3026too, are asynchronous in nature, and signals, too, will be compressed
3028(i.e. the number of callback invocations may be less than the number of 3027(i.e. the number of callback invocations may be less than the number of
3029C<ev_async_sent> calls). 3028C<ev_async_sent> calls).
… …
4397I suggest using suppression lists. 4396I suggest using suppression lists.
4398 4397
4399 4398
4400=head1 PORTABILITY NOTES 4399=head1 PORTABILITY NOTES
4401 4400
4401=head2 GNU/LINUX 32 BIT LIMITATIONS
4402
4403GNU/Linux is the only common platform that supports 64 bit file/large file
4404interfaces but disables them by default.
4405
4406That means that libev compiled in the default environment doesn't support
4407files larger than 2GiB, which mainly affects C<ev_stat> watchers.
4408
4409Unfortunately, many programs try to work around this GNU/Linux issue
4410by enabling the large file API, which makes them incompatible with the
4411standard libev compiled for their system.
4412
4413Likewise, libev cannot enable the large file API itself as this would
4414suddenly make it incompatible to the default compile time environment,
4415i.e. all programs not using special compile switches.
4416
4417=head2 OS/X AND DARWIN BUGS
4418
4419The whole thing is a bug if you ask me - basically any system interface
4420you touch is broken, whether it is locales, poll, kqueue or even their
4421OpenGL drivers.
4422
4423=over 4
4424
4425=item KQUEUE IS BUGGY
4426
4427The kqueue syscall is broken in all known versions - most versions support
4428only sockets, many support pipes.
4429
4430=item POLL IS BUGGY
4431
4432Instead of fixing C<kqueue>, Apple replaced their (working) C<poll>
4433implementation by something calling C<kqueue> internally around the 10.5.6
4434release, so now C<kqueue> I<and> C<poll> are broken.
4435
4436Libev tries to work around this by neither using C<kqueue> nor C<poll> by
4437default on this rotten platform, but of course you cna still ask for them
4438when creating a loop.
4439
4440=item SELECT IS BUGGY
4441
4442All that's left is C<select>, and of course Apple found a way to fuck this
4443one up as well: On OS/X, C<select> actively limits the number of file
4444descriptors you can pass in to 1024 - your program suddenyl crashes when
4445you use more.
4446
4447There is an undocumented "workaround" for this - defining
4448C<_DARWIN_UNLIMITED_SELECT>, which libev tries to use, so select I<should>
4449work on OS/X.
4450
4451=back
4452
4453=head2 SOLARIS PROBLEMS AND WORKAROUNDS
4454
4455=over 4
4456
4457=item C<errno> reentrancy
4458
4459The default compile environment on Solaris is unfortunately so
4460thread-unsafe that you can't even use components/libraries compiled
4461without C<-D_REENTRANT> (as long as they use C<errno>), which, of course,
4462isn't defined by default.
4463
4464If you want to use libev in threaded environments you have to make sure
4465it's compiled with C<_REENTRANT> defined.
4466
4467=item Event Port Backend
4468
4469The scalable event interface for Solaris is called "event ports". Unfortunately,
4470this mechanism is very buggy. If you run into high CPU usage, your program
4471freezes or you get a large number of spurious wakeups, make sure you have
4472all the relevant and latest kernel patches applied. No, I don't know which
4473ones, but there are multiple ones.
4474
4475If you can't get it to work, you can try running the program with
4476C<LIBEV_FLAGS=3> to only allow C<poll> and C<select> backends.
4477
4478=back
4479
4480=head2 AIX POLL BUG
4481
4482AIX unfortunately has a broken C<poll.h> header. Libev works around
4483this by trying to avoid the poll backend altogether (i.e. it's not even
4484compiled in), which normally isn't a big problem as C<select> works fine
4485with large bitsets, and AIX is dead anyway.
4486
4402=head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS 4487=head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS
4403 4488
4404Win32 doesn't support any of the standards (e.g. POSIX) that libev 4489Win32 doesn't support any of the standards (e.g. POSIX) that libev
4405requires, and its I/O model is fundamentally incompatible with the POSIX 4490requires, and its I/O model is fundamentally incompatible with the POSIX
4406model. Libev still offers limited functionality on this platform in 4491model. Libev still offers limited functionality on this platform in

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