… | |
… | |
131 | .\} |
131 | .\} |
132 | .rm #[ #] #H #V #F C |
132 | .rm #[ #] #H #V #F C |
133 | .\" ======================================================================== |
133 | .\" ======================================================================== |
134 | .\" |
134 | .\" |
135 | .IX Title "LIBEV 3" |
135 | .IX Title "LIBEV 3" |
136 | .TH LIBEV 3 "2019-06-23" "libev-4.25" "libev - high performance full featured event loop" |
136 | .TH LIBEV 3 "2019-12-20" "libev-4.27" "libev - high performance full featured event loop" |
137 | .\" For nroff, turn off justification. Always turn off hyphenation; it makes |
137 | .\" For nroff, turn off justification. Always turn off hyphenation; it makes |
138 | .\" way too many mistakes in technical documents. |
138 | .\" way too many mistakes in technical documents. |
139 | .if n .ad l |
139 | .if n .ad l |
140 | .nh |
140 | .nh |
141 | .SH "NAME" |
141 | .SH "NAME" |
… | |
… | |
291 | When libev detects a usage error such as a negative timer interval, then |
291 | When libev detects a usage error such as a negative timer interval, then |
292 | it will print a diagnostic message and abort (via the \f(CW\*(C`assert\*(C'\fR mechanism, |
292 | it will print a diagnostic message and abort (via the \f(CW\*(C`assert\*(C'\fR mechanism, |
293 | so \f(CW\*(C`NDEBUG\*(C'\fR will disable this checking): these are programming errors in |
293 | so \f(CW\*(C`NDEBUG\*(C'\fR will disable this checking): these are programming errors in |
294 | the libev caller and need to be fixed there. |
294 | the libev caller and need to be fixed there. |
295 | .PP |
295 | .PP |
|
|
296 | Via the \f(CW\*(C`EV_FREQUENT\*(C'\fR macro you can compile in and/or enable extensive |
|
|
297 | consistency checking code inside libev that can be used to check for |
|
|
298 | internal inconsistencies, suually caused by application bugs. |
|
|
299 | .PP |
296 | Libev also has a few internal error-checking \f(CW\*(C`assert\*(C'\fRions, and also has |
300 | Libev also has a few internal error-checking \f(CW\*(C`assert\*(C'\fRions. These do not |
297 | extensive consistency checking code. These do not trigger under normal |
|
|
298 | circumstances, as they indicate either a bug in libev or worse. |
301 | trigger under normal circumstances, as they indicate either a bug in libev |
|
|
302 | or worse. |
299 | .SH "GLOBAL FUNCTIONS" |
303 | .SH "GLOBAL FUNCTIONS" |
300 | .IX Header "GLOBAL FUNCTIONS" |
304 | .IX Header "GLOBAL FUNCTIONS" |
301 | These functions can be called anytime, even before initialising the |
305 | These functions can be called anytime, even before initialising the |
302 | library in any way. |
306 | library in any way. |
303 | .IP "ev_tstamp ev_time ()" 4 |
307 | .IP "ev_tstamp ev_time ()" 4 |
… | |
… | |
589 | threads that are not interested in handling them. |
593 | threads that are not interested in handling them. |
590 | .Sp |
594 | .Sp |
591 | Signalfd will not be used by default as this changes your signal mask, and |
595 | Signalfd will not be used by default as this changes your signal mask, and |
592 | there are a lot of shoddy libraries and programs (glib's threadpool for |
596 | there are a lot of shoddy libraries and programs (glib's threadpool for |
593 | example) that can't properly initialise their signal masks. |
597 | example) that can't properly initialise their signal masks. |
|
|
598 | .ie n .IP """EVFLAG_NOTIMERFD""" 4 |
|
|
599 | .el .IP "\f(CWEVFLAG_NOTIMERFD\fR" 4 |
|
|
600 | .IX Item "EVFLAG_NOTIMERFD" |
|
|
601 | When this flag is specified, the libev will avoid using a \f(CW\*(C`timerfd\*(C'\fR to |
|
|
602 | detect time jumps. It will still be able to detect time jumps, but takes |
|
|
603 | longer and has a lower accuracy in doing so, but saves a file descriptor |
|
|
604 | per loop. |
594 | .ie n .IP """EVFLAG_NOSIGMASK""" 4 |
605 | .ie n .IP """EVFLAG_NOSIGMASK""" 4 |
595 | .el .IP "\f(CWEVFLAG_NOSIGMASK\fR" 4 |
606 | .el .IP "\f(CWEVFLAG_NOSIGMASK\fR" 4 |
596 | .IX Item "EVFLAG_NOSIGMASK" |
607 | .IX Item "EVFLAG_NOSIGMASK" |
597 | When this flag is specified, then libev will avoid to modify the signal |
608 | When this flag is specified, then libev will avoid to modify the signal |
598 | mask. Specifically, this means you have to make sure signals are unblocked |
609 | mask. Specifically, this means you have to make sure signals are unblocked |
… | |
… | |
638 | This backend maps \f(CW\*(C`EV_READ\*(C'\fR to \f(CW\*(C`POLLIN | POLLERR | POLLHUP\*(C'\fR, and |
649 | This backend maps \f(CW\*(C`EV_READ\*(C'\fR to \f(CW\*(C`POLLIN | POLLERR | POLLHUP\*(C'\fR, and |
639 | \&\f(CW\*(C`EV_WRITE\*(C'\fR to \f(CW\*(C`POLLOUT | POLLERR | POLLHUP\*(C'\fR. |
650 | \&\f(CW\*(C`EV_WRITE\*(C'\fR to \f(CW\*(C`POLLOUT | POLLERR | POLLHUP\*(C'\fR. |
640 | .ie n .IP """EVBACKEND_EPOLL"" (value 4, Linux)" 4 |
651 | .ie n .IP """EVBACKEND_EPOLL"" (value 4, Linux)" 4 |
641 | .el .IP "\f(CWEVBACKEND_EPOLL\fR (value 4, Linux)" 4 |
652 | .el .IP "\f(CWEVBACKEND_EPOLL\fR (value 4, Linux)" 4 |
642 | .IX Item "EVBACKEND_EPOLL (value 4, Linux)" |
653 | .IX Item "EVBACKEND_EPOLL (value 4, Linux)" |
643 | Use the linux-specific \fBepoll\fR\|(7) interface (for both pre\- and post\-2.6.9 |
654 | Use the Linux-specific \fBepoll\fR\|(7) interface (for both pre\- and post\-2.6.9 |
644 | kernels). |
655 | kernels). |
645 | .Sp |
656 | .Sp |
646 | For few fds, this backend is a bit little slower than poll and select, but |
657 | For few fds, this backend is a bit little slower than poll and select, but |
647 | it scales phenomenally better. While poll and select usually scale like |
658 | it scales phenomenally better. While poll and select usually scale like |
648 | O(total_fds) where total_fds is the total number of fds (or the highest |
659 | O(total_fds) where total_fds is the total number of fds (or the highest |
… | |
… | |
701 | This backend maps \f(CW\*(C`EV_READ\*(C'\fR and \f(CW\*(C`EV_WRITE\*(C'\fR in the same way as |
712 | This backend maps \f(CW\*(C`EV_READ\*(C'\fR and \f(CW\*(C`EV_WRITE\*(C'\fR in the same way as |
702 | \&\f(CW\*(C`EVBACKEND_POLL\*(C'\fR. |
713 | \&\f(CW\*(C`EVBACKEND_POLL\*(C'\fR. |
703 | .ie n .IP """EVBACKEND_LINUXAIO"" (value 64, Linux)" 4 |
714 | .ie n .IP """EVBACKEND_LINUXAIO"" (value 64, Linux)" 4 |
704 | .el .IP "\f(CWEVBACKEND_LINUXAIO\fR (value 64, Linux)" 4 |
715 | .el .IP "\f(CWEVBACKEND_LINUXAIO\fR (value 64, Linux)" 4 |
705 | .IX Item "EVBACKEND_LINUXAIO (value 64, Linux)" |
716 | .IX Item "EVBACKEND_LINUXAIO (value 64, Linux)" |
706 | Use the linux-specific linux aio (\fInot\fR \f(CWaio(7)\fR but \f(CWio_submit(2)\fR) event interface available in post\-4.18 kernels. |
717 | Use the Linux-specific Linux \s-1AIO\s0 (\fInot\fR \f(CWaio(7)\fR but \f(CWio_submit(2)\fR) event interface available in post\-4.18 kernels (but libev |
|
|
718 | only tries to use it in 4.19+). |
|
|
719 | .Sp |
|
|
720 | This is another Linux train wreck of an event interface. |
707 | .Sp |
721 | .Sp |
708 | If this backend works for you (as of this writing, it was very |
722 | If this backend works for you (as of this writing, it was very |
709 | experimental), it is the best event interface available on linux and might |
723 | experimental), it is the best event interface available on Linux and might |
710 | be well worth enabling it \- if it isn't available in your kernel this will |
724 | be well worth enabling it \- if it isn't available in your kernel this will |
711 | be detected and this backend will be skipped. |
725 | be detected and this backend will be skipped. |
712 | .Sp |
726 | .Sp |
713 | This backend can batch oneshot requests and supports a user-space ring |
727 | This backend can batch oneshot requests and supports a user-space ring |
714 | buffer to receive events. It also doesn't suffer from most of the design |
728 | buffer to receive events. It also doesn't suffer from most of the design |
715 | problems of epoll (such as not being able to remove event sources from |
729 | problems of epoll (such as not being able to remove event sources from |
716 | the epoll set), and generally sounds too good to be true. Because, this |
730 | the epoll set), and generally sounds too good to be true. Because, this |
717 | being the linux kernel, of course it suffers from a whole new set of |
731 | being the Linux kernel, of course it suffers from a whole new set of |
718 | limitations. |
732 | limitations, forcing you to fall back to epoll, inheriting all its design |
|
|
733 | issues. |
719 | .Sp |
734 | .Sp |
720 | For one, it is not easily embeddable (but probably could be done using |
735 | For one, it is not easily embeddable (but probably could be done using |
721 | an event fd at some extra overhead). It also is subject to a system wide |
736 | an event fd at some extra overhead). It also is subject to a system wide |
722 | limit that can be configured in \fI/proc/sys/fs/aio\-max\-nr\fR \- each loop |
737 | limit that can be configured in \fI/proc/sys/fs/aio\-max\-nr\fR. If no \s-1AIO\s0 |
723 | currently requires \f(CW61\fR of this number. If no aio requests are left, this |
|
|
724 | backend will be skipped during initialisation. |
738 | requests are left, this backend will be skipped during initialisation, and |
|
|
739 | will switch to epoll when the loop is active. |
725 | .Sp |
740 | .Sp |
726 | Most problematic in practise, however, is that not all file descriptors |
741 | Most problematic in practice, however, is that not all file descriptors |
727 | work with it. For example, in linux 5.1, tcp sockets, pipes, event fds, |
742 | work with it. For example, in Linux 5.1, \s-1TCP\s0 sockets, pipes, event fds, |
728 | files, \fI/dev/null\fR and a few others are supported, but ttys do not work |
743 | files, \fI/dev/null\fR and many others are supported, but ttys do not work |
729 | (probably because of a bug), so this is not (yet?) a generic event polling |
744 | properly (a known bug that the kernel developers don't care about, see |
730 | interface. |
745 | <https://lore.kernel.org/patchwork/patch/1047453/>), so this is not |
|
|
746 | (yet?) a generic event polling interface. |
731 | .Sp |
747 | .Sp |
|
|
748 | Overall, it seems the Linux developers just don't want it to have a |
|
|
749 | generic event handling mechanism other than \f(CW\*(C`select\*(C'\fR or \f(CW\*(C`poll\*(C'\fR. |
|
|
750 | .Sp |
732 | To work around this latter problem, the current version of libev uses |
751 | To work around all these problem, the current version of libev uses its |
733 | epoll as a fallback for file deescriptor types that do not work. Epoll |
752 | epoll backend as a fallback for file descriptor types that do not work. Or |
734 | is used in, kind of, slow mode that hopefully avoids most of its design |
753 | falls back completely to epoll if the kernel acts up. |
735 | problems and requires 1\-3 extra syscalls per active fd every iteration. |
|
|
736 | .Sp |
754 | .Sp |
737 | This backend maps \f(CW\*(C`EV_READ\*(C'\fR and \f(CW\*(C`EV_WRITE\*(C'\fR in the same way as |
755 | This backend maps \f(CW\*(C`EV_READ\*(C'\fR and \f(CW\*(C`EV_WRITE\*(C'\fR in the same way as |
738 | \&\f(CW\*(C`EVBACKEND_POLL\*(C'\fR. |
756 | \&\f(CW\*(C`EVBACKEND_POLL\*(C'\fR. |
739 | .ie n .IP """EVBACKEND_KQUEUE"" (value 8, most \s-1BSD\s0 clones)" 4 |
757 | .ie n .IP """EVBACKEND_KQUEUE"" (value 8, most \s-1BSD\s0 clones)" 4 |
740 | .el .IP "\f(CWEVBACKEND_KQUEUE\fR (value 8, most \s-1BSD\s0 clones)" 4 |
758 | .el .IP "\f(CWEVBACKEND_KQUEUE\fR (value 8, most \s-1BSD\s0 clones)" 4 |
741 | .IX Item "EVBACKEND_KQUEUE (value 8, most BSD clones)" |
759 | .IX Item "EVBACKEND_KQUEUE (value 8, most BSD clones)" |
742 | Kqueue deserves special mention, as at the time of this writing, it |
760 | Kqueue deserves special mention, as at the time this backend was |
743 | was broken on all BSDs except NetBSD (usually it doesn't work reliably |
761 | implemented, it was broken on all BSDs except NetBSD (usually it doesn't |
744 | with anything but sockets and pipes, except on Darwin, where of course |
762 | work reliably with anything but sockets and pipes, except on Darwin, |
745 | it's completely useless). Unlike epoll, however, whose brokenness |
763 | where of course it's completely useless). Unlike epoll, however, whose |
746 | is by design, these kqueue bugs can (and eventually will) be fixed |
764 | brokenness is by design, these kqueue bugs can be (and mostly have been) |
747 | without \s-1API\s0 changes to existing programs. For this reason it's not being |
765 | fixed without \s-1API\s0 changes to existing programs. For this reason it's not |
748 | \&\*(L"auto-detected\*(R" unless you explicitly specify it in the flags (i.e. using |
766 | being \*(L"auto-detected\*(R" on all platforms unless you explicitly specify it |
749 | \&\f(CW\*(C`EVBACKEND_KQUEUE\*(C'\fR) or libev was compiled on a known-to-be-good (\-enough) |
767 | in the flags (i.e. using \f(CW\*(C`EVBACKEND_KQUEUE\*(C'\fR) or libev was compiled on a |
750 | system like NetBSD. |
768 | known-to-be-good (\-enough) system like NetBSD. |
751 | .Sp |
769 | .Sp |
752 | You still can embed kqueue into a normal poll or select backend and use it |
770 | You still can embed kqueue into a normal poll or select backend and use it |
753 | only for sockets (after having made sure that sockets work with kqueue on |
771 | only for sockets (after having made sure that sockets work with kqueue on |
754 | the target platform). See \f(CW\*(C`ev_embed\*(C'\fR watchers for more info. |
772 | the target platform). See \f(CW\*(C`ev_embed\*(C'\fR watchers for more info. |
755 | .Sp |
773 | .Sp |
756 | It scales in the same way as the epoll backend, but the interface to the |
774 | It scales in the same way as the epoll backend, but the interface to the |
757 | kernel is more efficient (which says nothing about its actual speed, of |
775 | kernel is more efficient (which says nothing about its actual speed, of |
758 | course). While stopping, setting and starting an I/O watcher does never |
776 | course). While stopping, setting and starting an I/O watcher does never |
759 | cause an extra system call as with \f(CW\*(C`EVBACKEND_EPOLL\*(C'\fR, it still adds up to |
777 | cause an extra system call as with \f(CW\*(C`EVBACKEND_EPOLL\*(C'\fR, it still adds up to |
760 | two event changes per incident. Support for \f(CW\*(C`fork ()\*(C'\fR is very bad (you |
778 | two event changes per incident. Support for \f(CW\*(C`fork ()\*(C'\fR is very bad (you |
761 | might have to leak fd's on fork, but it's more sane than epoll) and it |
779 | might have to leak fds on fork, but it's more sane than epoll) and it |
762 | drops fds silently in similarly hard-to-detect cases. |
780 | drops fds silently in similarly hard-to-detect cases. |
763 | .Sp |
781 | .Sp |
764 | This backend usually performs well under most conditions. |
782 | This backend usually performs well under most conditions. |
765 | .Sp |
783 | .Sp |
766 | While nominally embeddable in other event loops, this doesn't work |
784 | While nominally embeddable in other event loops, this doesn't work |
… | |
… | |
1643 | .IX Subsection "WATCHER PRIORITY MODELS" |
1661 | .IX Subsection "WATCHER PRIORITY MODELS" |
1644 | Many event loops support \fIwatcher priorities\fR, which are usually small |
1662 | Many event loops support \fIwatcher priorities\fR, which are usually small |
1645 | integers that influence the ordering of event callback invocation |
1663 | integers that influence the ordering of event callback invocation |
1646 | between watchers in some way, all else being equal. |
1664 | between watchers in some way, all else being equal. |
1647 | .PP |
1665 | .PP |
1648 | In libev, Watcher priorities can be set using \f(CW\*(C`ev_set_priority\*(C'\fR. See its |
1666 | In libev, watcher priorities can be set using \f(CW\*(C`ev_set_priority\*(C'\fR. See its |
1649 | description for the more technical details such as the actual priority |
1667 | description for the more technical details such as the actual priority |
1650 | range. |
1668 | range. |
1651 | .PP |
1669 | .PP |
1652 | There are two common ways how these these priorities are being interpreted |
1670 | There are two common ways how these these priorities are being interpreted |
1653 | by event loops: |
1671 | by event loops: |
… | |
… | |
1860 | reuse the same code path. |
1878 | reuse the same code path. |
1861 | .PP |
1879 | .PP |
1862 | \fIThe special problem of fork\fR |
1880 | \fIThe special problem of fork\fR |
1863 | .IX Subsection "The special problem of fork" |
1881 | .IX Subsection "The special problem of fork" |
1864 | .PP |
1882 | .PP |
1865 | Some backends (epoll, kqueue, probably linuxaio) do not support \f(CW\*(C`fork ()\*(C'\fR |
1883 | Some backends (epoll, kqueue, linuxaio, iouring) do not support \f(CW\*(C`fork ()\*(C'\fR |
1866 | at all or exhibit useless behaviour. Libev fully supports fork, but needs |
1884 | at all or exhibit useless behaviour. Libev fully supports fork, but needs |
1867 | to be told about it in the child if you want to continue to use it in the |
1885 | to be told about it in the child if you want to continue to use it in the |
1868 | child. |
1886 | child. |
1869 | .PP |
1887 | .PP |
1870 | To support fork in your child processes, you have to call \f(CW\*(C`ev_loop_fork |
1888 | To support fork in your child processes, you have to call \f(CW\*(C`ev_loop_fork |
… | |
… | |
4613 | \& |
4631 | \& |
4614 | \& ev_select.c only when select backend is enabled |
4632 | \& ev_select.c only when select backend is enabled |
4615 | \& ev_poll.c only when poll backend is enabled |
4633 | \& ev_poll.c only when poll backend is enabled |
4616 | \& ev_epoll.c only when the epoll backend is enabled |
4634 | \& ev_epoll.c only when the epoll backend is enabled |
4617 | \& ev_linuxaio.c only when the linux aio backend is enabled |
4635 | \& ev_linuxaio.c only when the linux aio backend is enabled |
|
|
4636 | \& ev_iouring.c only when the linux io_uring backend is enabled |
4618 | \& ev_kqueue.c only when the kqueue backend is enabled |
4637 | \& ev_kqueue.c only when the kqueue backend is enabled |
4619 | \& ev_port.c only when the solaris port backend is enabled |
4638 | \& ev_port.c only when the solaris port backend is enabled |
4620 | .Ve |
4639 | .Ve |
4621 | .PP |
4640 | .PP |
4622 | \&\fIev.c\fR includes the backend files directly when enabled, so you only need |
4641 | \&\fIev.c\fR includes the backend files directly when enabled, so you only need |
… | |
… | |
4735 | higher, as it simplifies linking (no need for \f(CW\*(C`\-lrt\*(C'\fR). |
4754 | higher, as it simplifies linking (no need for \f(CW\*(C`\-lrt\*(C'\fR). |
4736 | .IP "\s-1EV_USE_NANOSLEEP\s0" 4 |
4755 | .IP "\s-1EV_USE_NANOSLEEP\s0" 4 |
4737 | .IX Item "EV_USE_NANOSLEEP" |
4756 | .IX Item "EV_USE_NANOSLEEP" |
4738 | If defined to be \f(CW1\fR, libev will assume that \f(CW\*(C`nanosleep ()\*(C'\fR is available |
4757 | If defined to be \f(CW1\fR, libev will assume that \f(CW\*(C`nanosleep ()\*(C'\fR is available |
4739 | and will use it for delays. Otherwise it will use \f(CW\*(C`select ()\*(C'\fR. |
4758 | and will use it for delays. Otherwise it will use \f(CW\*(C`select ()\*(C'\fR. |
|
|
4759 | .IP "\s-1EV_USE_EVENTFD\s0" 4 |
|
|
4760 | .IX Item "EV_USE_EVENTFD" |
|
|
4761 | If defined to be \f(CW1\fR, then libev will assume that \f(CW\*(C`eventfd ()\*(C'\fR is |
|
|
4762 | available and will probe for kernel support at runtime. This will improve |
|
|
4763 | \&\f(CW\*(C`ev_signal\*(C'\fR and \f(CW\*(C`ev_async\*(C'\fR performance and reduce resource consumption. |
|
|
4764 | If undefined, it will be enabled if the headers indicate GNU/Linux + Glibc |
|
|
4765 | 2.7 or newer, otherwise disabled. |
|
|
4766 | .IP "\s-1EV_USE_SIGNALFD\s0" 4 |
|
|
4767 | .IX Item "EV_USE_SIGNALFD" |
|
|
4768 | If defined to be \f(CW1\fR, then libev will assume that \f(CW\*(C`signalfd ()\*(C'\fR is |
|
|
4769 | available and will probe for kernel support at runtime. This enables |
|
|
4770 | the use of \s-1EVFLAG_SIGNALFD\s0 for faster and simpler signal handling. If |
|
|
4771 | undefined, it will be enabled if the headers indicate GNU/Linux + Glibc |
|
|
4772 | 2.7 or newer, otherwise disabled. |
|
|
4773 | .IP "\s-1EV_USE_TIMERFD\s0" 4 |
|
|
4774 | .IX Item "EV_USE_TIMERFD" |
|
|
4775 | If defined to be \f(CW1\fR, then libev will assume that \f(CW\*(C`timerfd ()\*(C'\fR is |
|
|
4776 | available and will probe for kernel support at runtime. This allows |
|
|
4777 | libev to detect time jumps accurately. If undefined, it will be enabled |
|
|
4778 | if the headers indicate GNU/Linux + Glibc 2.8 or newer and define |
|
|
4779 | \&\f(CW\*(C`TFD_TIMER_CANCEL_ON_SET\*(C'\fR, otherwise disabled. |
4740 | .IP "\s-1EV_USE_EVENTFD\s0" 4 |
4780 | .IP "\s-1EV_USE_EVENTFD\s0" 4 |
4741 | .IX Item "EV_USE_EVENTFD" |
4781 | .IX Item "EV_USE_EVENTFD" |
4742 | If defined to be \f(CW1\fR, then libev will assume that \f(CW\*(C`eventfd ()\*(C'\fR is |
4782 | If defined to be \f(CW1\fR, then libev will assume that \f(CW\*(C`eventfd ()\*(C'\fR is |
4743 | available and will probe for kernel support at runtime. This will improve |
4783 | available and will probe for kernel support at runtime. This will improve |
4744 | \&\f(CW\*(C`ev_signal\*(C'\fR and \f(CW\*(C`ev_async\*(C'\fR performance and reduce resource consumption. |
4784 | \&\f(CW\*(C`ev_signal\*(C'\fR and \f(CW\*(C`ev_async\*(C'\fR performance and reduce resource consumption. |
… | |
… | |
4805 | otherwise another method will be used as fallback. This is the preferred |
4845 | otherwise another method will be used as fallback. This is the preferred |
4806 | backend for GNU/Linux systems. If undefined, it will be enabled if the |
4846 | backend for GNU/Linux systems. If undefined, it will be enabled if the |
4807 | headers indicate GNU/Linux + Glibc 2.4 or newer, otherwise disabled. |
4847 | headers indicate GNU/Linux + Glibc 2.4 or newer, otherwise disabled. |
4808 | .IP "\s-1EV_USE_LINUXAIO\s0" 4 |
4848 | .IP "\s-1EV_USE_LINUXAIO\s0" 4 |
4809 | .IX Item "EV_USE_LINUXAIO" |
4849 | .IX Item "EV_USE_LINUXAIO" |
|
|
4850 | If defined to be \f(CW1\fR, libev will compile in support for the Linux aio |
|
|
4851 | backend (\f(CW\*(C`EV_USE_EPOLL\*(C'\fR must also be enabled). If undefined, it will be |
|
|
4852 | enabled on linux, otherwise disabled. |
|
|
4853 | .IP "\s-1EV_USE_IOURING\s0" 4 |
|
|
4854 | .IX Item "EV_USE_IOURING" |
4810 | If defined to be \f(CW1\fR, libev will compile in support for the Linux |
4855 | If defined to be \f(CW1\fR, libev will compile in support for the Linux |
4811 | aio backend. Due to it's currenbt limitations it has to be requested |
4856 | io_uring backend (\f(CW\*(C`EV_USE_EPOLL\*(C'\fR must also be enabled). Due to it's |
4812 | explicitly. If undefined, it will be enabled on linux, otherwise |
4857 | current limitations it has to be requested explicitly. If undefined, it |
4813 | disabled. |
4858 | will be enabled on linux, otherwise disabled. |
4814 | .IP "\s-1EV_USE_KQUEUE\s0" 4 |
4859 | .IP "\s-1EV_USE_KQUEUE\s0" 4 |
4815 | .IX Item "EV_USE_KQUEUE" |
4860 | .IX Item "EV_USE_KQUEUE" |
4816 | If defined to be \f(CW1\fR, libev will compile in support for the \s-1BSD\s0 style |
4861 | If defined to be \f(CW1\fR, libev will compile in support for the \s-1BSD\s0 style |
4817 | \&\f(CW\*(C`kqueue\*(C'\fR(2) backend. Its actual availability will be detected at runtime, |
4862 | \&\f(CW\*(C`kqueue\*(C'\fR(2) backend. Its actual availability will be detected at runtime, |
4818 | otherwise another method will be used as fallback. This is the preferred |
4863 | otherwise another method will be used as fallback. This is the preferred |
… | |
… | |
5074 | in. If set to \f(CW1\fR, then verification code will be compiled in, but not |
5119 | in. If set to \f(CW1\fR, then verification code will be compiled in, but not |
5075 | called. If set to \f(CW2\fR, then the internal verification code will be |
5120 | called. If set to \f(CW2\fR, then the internal verification code will be |
5076 | called once per loop, which can slow down libev. If set to \f(CW3\fR, then the |
5121 | called once per loop, which can slow down libev. If set to \f(CW3\fR, then the |
5077 | verification code will be called very frequently, which will slow down |
5122 | verification code will be called very frequently, which will slow down |
5078 | libev considerably. |
5123 | libev considerably. |
|
|
5124 | .Sp |
|
|
5125 | Verification errors are reported via C's \f(CW\*(C`assert\*(C'\fR mechanism, so if you |
|
|
5126 | disable that (e.g. by defining \f(CW\*(C`NDEBUG\*(C'\fR) then no errors will be reported. |
5079 | .Sp |
5127 | .Sp |
5080 | The default is \f(CW1\fR, unless \f(CW\*(C`EV_FEATURES\*(C'\fR overrides it, in which case it |
5128 | The default is \f(CW1\fR, unless \f(CW\*(C`EV_FEATURES\*(C'\fR overrides it, in which case it |
5081 | will be \f(CW0\fR. |
5129 | will be \f(CW0\fR. |
5082 | .IP "\s-1EV_COMMON\s0" 4 |
5130 | .IP "\s-1EV_COMMON\s0" 4 |
5083 | .IX Item "EV_COMMON" |
5131 | .IX Item "EV_COMMON" |