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Revision 1.112 by root, Sun Jun 23 23:27:34 2019 UTC vs.
Revision 1.118 by root, Sat Dec 21 16:11:51 2019 UTC

… …
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 "2019-12-21" "libev-4.31" "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"
… …
291When libev detects a usage error such as a negative timer interval, then 291When libev detects a usage error such as a negative timer interval, then
292it will print a diagnostic message and abort (via the \f(CW\*(C`assert\*(C'\fR mechanism, 292it will print a diagnostic message and abort (via the \f(CW\*(C`assert\*(C'\fR mechanism,
293so \f(CW\*(C`NDEBUG\*(C'\fR will disable this checking): these are programming errors in 293so \f(CW\*(C`NDEBUG\*(C'\fR will disable this checking): these are programming errors in
294the libev caller and need to be fixed there. 294the libev caller and need to be fixed there.
295.PP 295.PP
296Via the \f(CW\*(C`EV_FREQUENT\*(C'\fR macro you can compile in and/or enable extensive
297consistency checking code inside libev that can be used to check for
298internal inconsistencies, suually caused by application bugs.
299.PP
296Libev also has a few internal error-checking \f(CW\*(C`assert\*(C'\fRions, and also has 300Libev also has a few internal error-checking \f(CW\*(C`assert\*(C'\fRions. These do not
297extensive consistency checking code. These do not trigger under normal
298circumstances, as they indicate either a bug in libev or worse. 301trigger under normal circumstances, as they indicate either a bug in libev
302or worse.
299.SH "GLOBAL FUNCTIONS" 303.SH "GLOBAL FUNCTIONS"
300.IX Header "GLOBAL FUNCTIONS" 304.IX Header "GLOBAL FUNCTIONS"
301These functions can be called anytime, even before initialising the 305These functions can be called anytime, even before initialising the
302library in any way. 306library in any way.
303.IP "ev_tstamp ev_time ()" 4 307.IP "ev_tstamp ev_time ()" 4
… …
602want to handle signals only in specific threads and want to avoid libev 606want to handle signals only in specific threads and want to avoid libev
603unblocking the signals. 607unblocking the signals.
604.Sp 608.Sp
605It's also required by \s-1POSIX\s0 in a threaded program, as libev calls 609It's also required by \s-1POSIX\s0 in a threaded program, as libev calls
606\&\f(CW\*(C`sigprocmask\*(C'\fR, whose behaviour is officially unspecified. 610\&\f(CW\*(C`sigprocmask\*(C'\fR, whose behaviour is officially unspecified.
611.ie n .IP """EVFLAG_NOTIMERFD""" 4
612.el .IP "\f(CWEVFLAG_NOTIMERFD\fR" 4
613.IX Item "EVFLAG_NOTIMERFD"
614When this flag is specified, the libev will avoid using a \f(CW\*(C`timerfd\*(C'\fR to
615detect time jumps. It will still be able to detect time jumps, but takes
616longer and has a lower accuracy in doing so, but saves a file descriptor
617per loop.
607.Sp 618.Sp
608This flag's behaviour will become the default in future versions of libev. 619The current implementation only tries to use a \f(CW\*(C`timerfd\*(C'\fR when the first
620\&\f(CW\*(C`ev_periodic\*(C'\fR watcher is started and falls back on other methods if it
621cannot be created, but this behaviour might change in the future.
609.ie n .IP """EVBACKEND_SELECT"" (value 1, portable select backend)" 4 622.ie n .IP """EVBACKEND_SELECT"" (value 1, portable select backend)" 4
610.el .IP "\f(CWEVBACKEND_SELECT\fR (value 1, portable select backend)" 4 623.el .IP "\f(CWEVBACKEND_SELECT\fR (value 1, portable select backend)" 4
611.IX Item "EVBACKEND_SELECT (value 1, portable select backend)" 624.IX Item "EVBACKEND_SELECT (value 1, portable select backend)"
612This is your standard \fBselect\fR\|(2) backend. Not \fIcompletely\fR standard, as 625This is your standard \fBselect\fR\|(2) backend. Not \fIcompletely\fR standard, as
613libev tries to roll its own fd_set with no limits on the number of fds, 626libev tries to roll its own fd_set with no limits on the number of fds,
… …
638This backend maps \f(CW\*(C`EV_READ\*(C'\fR to \f(CW\*(C`POLLIN | POLLERR | POLLHUP\*(C'\fR, and 651This 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. 652\&\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)" 4 653.ie n .IP """EVBACKEND_EPOLL"" (value 4, Linux)" 4
641.el .IP "\f(CWEVBACKEND_EPOLL\fR (value 4, Linux)" 4 654.el .IP "\f(CWEVBACKEND_EPOLL\fR (value 4, Linux)" 4
642.IX Item "EVBACKEND_EPOLL (value 4, Linux)" 655.IX Item "EVBACKEND_EPOLL (value 4, Linux)"
643Use the linux-specific \fBepoll\fR\|(7) interface (for both pre\- and post\-2.6.9 656Use the Linux-specific \fBepoll\fR\|(7) interface (for both pre\- and post\-2.6.9
644kernels). 657kernels).
645.Sp 658.Sp
646For few fds, this backend is a bit little slower than poll and select, but 659For few fds, this backend is a bit little slower than poll and select, but
647it scales phenomenally better. While poll and select usually scale like 660it scales phenomenally better. While poll and select usually scale like
648O(total_fds) where total_fds is the total number of fds (or the highest 661O(total_fds) where total_fds is the total number of fds (or the highest
… …
701This backend maps \f(CW\*(C`EV_READ\*(C'\fR and \f(CW\*(C`EV_WRITE\*(C'\fR in the same way as 714This 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. 715\&\f(CW\*(C`EVBACKEND_POLL\*(C'\fR.
703.ie n .IP """EVBACKEND_LINUXAIO"" (value 64, Linux)" 4 716.ie n .IP """EVBACKEND_LINUXAIO"" (value 64, Linux)" 4
704.el .IP "\f(CWEVBACKEND_LINUXAIO\fR (value 64, Linux)" 4 717.el .IP "\f(CWEVBACKEND_LINUXAIO\fR (value 64, Linux)" 4
705.IX Item "EVBACKEND_LINUXAIO (value 64, Linux)" 718.IX Item "EVBACKEND_LINUXAIO (value 64, Linux)"
706Use 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. 719Use 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
720only tries to use it in 4.19+).
721.Sp
722This is another Linux train wreck of an event interface.
707.Sp 723.Sp
708If this backend works for you (as of this writing, it was very 724If this backend works for you (as of this writing, it was very
709experimental), it is the best event interface available on linux and might 725experimental), it is the best event interface available on Linux and might
710be well worth enabling it \- if it isn't available in your kernel this will 726be well worth enabling it \- if it isn't available in your kernel this will
711be detected and this backend will be skipped. 727be detected and this backend will be skipped.
712.Sp 728.Sp
713This backend can batch oneshot requests and supports a user-space ring 729This backend can batch oneshot requests and supports a user-space ring
714buffer to receive events. It also doesn't suffer from most of the design 730buffer to receive events. It also doesn't suffer from most of the design
715problems of epoll (such as not being able to remove event sources from 731problems of epoll (such as not being able to remove event sources from
716the epoll set), and generally sounds too good to be true. Because, this 732the epoll set), and generally sounds too good to be true. Because, this
717being the linux kernel, of course it suffers from a whole new set of 733being the Linux kernel, of course it suffers from a whole new set of
718limitations. 734limitations, forcing you to fall back to epoll, inheriting all its design
735issues.
719.Sp 736.Sp
720For one, it is not easily embeddable (but probably could be done using 737For one, it is not easily embeddable (but probably could be done using
721an event fd at some extra overhead). It also is subject to a system wide 738an event fd at some extra overhead). It also is subject to a system wide
722limit that can be configured in \fI/proc/sys/fs/aio\-max\-nr\fR \- each loop 739limit that can be configured in \fI/proc/sys/fs/aio\-max\-nr\fR. If no \s-1AIO\s0
723currently requires \f(CW61\fR of this number. If no aio requests are left, this
724backend will be skipped during initialisation. 740requests are left, this backend will be skipped during initialisation, and
741will switch to epoll when the loop is active.
725.Sp 742.Sp
726Most problematic in practise, however, is that not all file descriptors 743Most problematic in practice, however, is that not all file descriptors
727work with it. For example, in linux 5.1, tcp sockets, pipes, event fds, 744work with it. For example, in Linux 5.1, \s-1TCP\s0 sockets, pipes, event fds,
728files, \fI/dev/null\fR and a few others are supported, but ttys do not work 745files, \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 746properly (a known bug that the kernel developers don't care about, see
730interface. 747<https://lore.kernel.org/patchwork/patch/1047453/>), so this is not
748(yet?) a generic event polling interface.
731.Sp 749.Sp
750Overall, it seems the Linux developers just don't want it to have a
751generic event handling mechanism other than \f(CW\*(C`select\*(C'\fR or \f(CW\*(C`poll\*(C'\fR.
752.Sp
732To work around this latter problem, the current version of libev uses 753To work around all these problem, the current version of libev uses its
733epoll as a fallback for file deescriptor types that do not work. Epoll 754epoll backend as a fallback for file descriptor types that do not work. Or
734is used in, kind of, slow mode that hopefully avoids most of its design 755falls back completely to epoll if the kernel acts up.
735problems and requires 1\-3 extra syscalls per active fd every iteration.
736.Sp 756.Sp
737This backend maps \f(CW\*(C`EV_READ\*(C'\fR and \f(CW\*(C`EV_WRITE\*(C'\fR in the same way as 757This 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. 758\&\f(CW\*(C`EVBACKEND_POLL\*(C'\fR.
739.ie n .IP """EVBACKEND_KQUEUE"" (value 8, most \s-1BSD\s0 clones)" 4 759.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)" 4 760.el .IP "\f(CWEVBACKEND_KQUEUE\fR (value 8, most \s-1BSD\s0 clones)" 4
741.IX Item "EVBACKEND_KQUEUE (value 8, most BSD clones)" 761.IX Item "EVBACKEND_KQUEUE (value 8, most BSD clones)"
742Kqueue deserves special mention, as at the time of this writing, it 762Kqueue deserves special mention, as at the time this backend was
743was broken on all BSDs except NetBSD (usually it doesn't work reliably 763implemented, it was broken on all BSDs except NetBSD (usually it doesn't
744with anything but sockets and pipes, except on Darwin, where of course 764work reliably with anything but sockets and pipes, except on Darwin,
745it's completely useless). Unlike epoll, however, whose brokenness 765where of course it's completely useless). Unlike epoll, however, whose
746is by design, these kqueue bugs can (and eventually will) be fixed 766brokenness is by design, these kqueue bugs can be (and mostly have been)
747without \s-1API\s0 changes to existing programs. For this reason it's not being 767fixed 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 768being \*(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) 769in the flags (i.e. using \f(CW\*(C`EVBACKEND_KQUEUE\*(C'\fR) or libev was compiled on a
750system like NetBSD. 770known-to-be-good (\-enough) system like NetBSD.
751.Sp 771.Sp
752You still can embed kqueue into a normal poll or select backend and use it 772You still can embed kqueue into a normal poll or select backend and use it
753only for sockets (after having made sure that sockets work with kqueue on 773only for sockets (after having made sure that sockets work with kqueue on
754the target platform). See \f(CW\*(C`ev_embed\*(C'\fR watchers for more info. 774the target platform). See \f(CW\*(C`ev_embed\*(C'\fR watchers for more info.
755.Sp 775.Sp
756It scales in the same way as the epoll backend, but the interface to the 776It scales in the same way as the epoll backend, but the interface to the
757kernel is more efficient (which says nothing about its actual speed, of 777kernel is more efficient (which says nothing about its actual speed, of
758course). While stopping, setting and starting an I/O watcher does never 778course). While stopping, setting and starting an I/O watcher does never
759cause an extra system call as with \f(CW\*(C`EVBACKEND_EPOLL\*(C'\fR, it still adds up to 779cause an extra system call as with \f(CW\*(C`EVBACKEND_EPOLL\*(C'\fR, it still adds up to
760two event changes per incident. Support for \f(CW\*(C`fork ()\*(C'\fR is very bad (you 780two event changes per incident. Support for \f(CW\*(C`fork ()\*(C'\fR is very bad (you
761might have to leak fd's on fork, but it's more sane than epoll) and it 781might have to leak fds on fork, but it's more sane than epoll) and it
762drops fds silently in similarly hard-to-detect cases. 782drops fds silently in similarly hard-to-detect cases.
763.Sp 783.Sp
764This backend usually performs well under most conditions. 784This backend usually performs well under most conditions.
765.Sp 785.Sp
766While nominally embeddable in other event loops, this doesn't work 786While nominally embeddable in other event loops, this doesn't work
… …
1643.IX Subsection "WATCHER PRIORITY MODELS" 1663.IX Subsection "WATCHER PRIORITY MODELS"
1644Many event loops support \fIwatcher priorities\fR, which are usually small 1664Many event loops support \fIwatcher priorities\fR, which are usually small
1645integers that influence the ordering of event callback invocation 1665integers that influence the ordering of event callback invocation
1646between watchers in some way, all else being equal. 1666between watchers in some way, all else being equal.
1647.PP 1667.PP
1648In libev, Watcher priorities can be set using \f(CW\*(C`ev_set_priority\*(C'\fR. See its 1668In libev, watcher priorities can be set using \f(CW\*(C`ev_set_priority\*(C'\fR. See its
1649description for the more technical details such as the actual priority 1669description for the more technical details such as the actual priority
1650range. 1670range.
1651.PP 1671.PP
1652There are two common ways how these these priorities are being interpreted 1672There are two common ways how these these priorities are being interpreted
1653by event loops: 1673by event loops:
… …
1860reuse the same code path. 1880reuse the same code path.
1861.PP 1881.PP
1862\fIThe special problem of fork\fR 1882\fIThe special problem of fork\fR
1863.IX Subsection "The special problem of fork" 1883.IX Subsection "The special problem of fork"
1864.PP 1884.PP
1865Some backends (epoll, kqueue, probably linuxaio) do not support \f(CW\*(C`fork ()\*(C'\fR 1885Some backends (epoll, kqueue, linuxaio, iouring) do not support \f(CW\*(C`fork ()\*(C'\fR
1866at all or exhibit useless behaviour. Libev fully supports fork, but needs 1886at all or exhibit useless behaviour. Libev fully supports fork, but needs
1867to be told about it in the child if you want to continue to use it in the 1887to be told about it in the child if you want to continue to use it in the
1868child. 1888child.
1869.PP 1889.PP
1870To support fork in your child processes, you have to call \f(CW\*(C`ev_loop_fork 1890To support fork in your child processes, you have to call \f(CW\*(C`ev_loop_fork
… …
4613\& 4633\&
4614\& ev_select.c only when select backend is enabled 4634\& ev_select.c only when select backend is enabled
4615\& ev_poll.c only when poll backend is enabled 4635\& ev_poll.c only when poll backend is enabled
4616\& ev_epoll.c only when the epoll backend is enabled 4636\& ev_epoll.c only when the epoll backend is enabled
4617\& ev_linuxaio.c only when the linux aio backend is enabled 4637\& ev_linuxaio.c only when the linux aio backend is enabled
4638\& ev_iouring.c only when the linux io_uring backend is enabled
4618\& ev_kqueue.c only when the kqueue backend is enabled 4639\& ev_kqueue.c only when the kqueue backend is enabled
4619\& ev_port.c only when the solaris port backend is enabled 4640\& ev_port.c only when the solaris port backend is enabled
4620.Ve 4641.Ve
4621.PP 4642.PP
4622\&\fIev.c\fR includes the backend files directly when enabled, so you only need 4643\&\fIev.c\fR includes the backend files directly when enabled, so you only need
… …
4735higher, as it simplifies linking (no need for \f(CW\*(C`\-lrt\*(C'\fR). 4756higher, as it simplifies linking (no need for \f(CW\*(C`\-lrt\*(C'\fR).
4736.IP "\s-1EV_USE_NANOSLEEP\s0" 4 4757.IP "\s-1EV_USE_NANOSLEEP\s0" 4
4737.IX Item "EV_USE_NANOSLEEP" 4758.IX Item "EV_USE_NANOSLEEP"
4738If defined to be \f(CW1\fR, libev will assume that \f(CW\*(C`nanosleep ()\*(C'\fR is available 4759If defined to be \f(CW1\fR, libev will assume that \f(CW\*(C`nanosleep ()\*(C'\fR is available
4739and will use it for delays. Otherwise it will use \f(CW\*(C`select ()\*(C'\fR. 4760and will use it for delays. Otherwise it will use \f(CW\*(C`select ()\*(C'\fR.
4761.IP "\s-1EV_USE_EVENTFD\s0" 4
4762.IX Item "EV_USE_EVENTFD"
4763If defined to be \f(CW1\fR, then libev will assume that \f(CW\*(C`eventfd ()\*(C'\fR is
4764available and will probe for kernel support at runtime. This will improve
4765\&\f(CW\*(C`ev_signal\*(C'\fR and \f(CW\*(C`ev_async\*(C'\fR performance and reduce resource consumption.
4766If undefined, it will be enabled if the headers indicate GNU/Linux + Glibc
47672.7 or newer, otherwise disabled.
4768.IP "\s-1EV_USE_SIGNALFD\s0" 4
4769.IX Item "EV_USE_SIGNALFD"
4770If defined to be \f(CW1\fR, then libev will assume that \f(CW\*(C`signalfd ()\*(C'\fR is
4771available and will probe for kernel support at runtime. This enables
4772the use of \s-1EVFLAG_SIGNALFD\s0 for faster and simpler signal handling. If
4773undefined, it will be enabled if the headers indicate GNU/Linux + Glibc
47742.7 or newer, otherwise disabled.
4775.IP "\s-1EV_USE_TIMERFD\s0" 4
4776.IX Item "EV_USE_TIMERFD"
4777If defined to be \f(CW1\fR, then libev will assume that \f(CW\*(C`timerfd ()\*(C'\fR is
4778available and will probe for kernel support at runtime. This allows
4779libev to detect time jumps accurately. If undefined, it will be enabled
4780if the headers indicate GNU/Linux + Glibc 2.8 or newer and define
4781\&\f(CW\*(C`TFD_TIMER_CANCEL_ON_SET\*(C'\fR, otherwise disabled.
4740.IP "\s-1EV_USE_EVENTFD\s0" 4 4782.IP "\s-1EV_USE_EVENTFD\s0" 4
4741.IX Item "EV_USE_EVENTFD" 4783.IX Item "EV_USE_EVENTFD"
4742If defined to be \f(CW1\fR, then libev will assume that \f(CW\*(C`eventfd ()\*(C'\fR is 4784If defined to be \f(CW1\fR, then libev will assume that \f(CW\*(C`eventfd ()\*(C'\fR is
4743available and will probe for kernel support at runtime. This will improve 4785available 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. 4786\&\f(CW\*(C`ev_signal\*(C'\fR and \f(CW\*(C`ev_async\*(C'\fR performance and reduce resource consumption.
… …
4805otherwise another method will be used as fallback. This is the preferred 4847otherwise another method will be used as fallback. This is the preferred
4806backend for GNU/Linux systems. If undefined, it will be enabled if the 4848backend for GNU/Linux systems. If undefined, it will be enabled if the
4807headers indicate GNU/Linux + Glibc 2.4 or newer, otherwise disabled. 4849headers indicate GNU/Linux + Glibc 2.4 or newer, otherwise disabled.
4808.IP "\s-1EV_USE_LINUXAIO\s0" 4 4850.IP "\s-1EV_USE_LINUXAIO\s0" 4
4809.IX Item "EV_USE_LINUXAIO" 4851.IX Item "EV_USE_LINUXAIO"
4852If defined to be \f(CW1\fR, libev will compile in support for the Linux aio
4853backend (\f(CW\*(C`EV_USE_EPOLL\*(C'\fR must also be enabled). If undefined, it will be
4854enabled on linux, otherwise disabled.
4855.IP "\s-1EV_USE_IOURING\s0" 4
4856.IX Item "EV_USE_IOURING"
4810If defined to be \f(CW1\fR, libev will compile in support for the Linux 4857If defined to be \f(CW1\fR, libev will compile in support for the Linux
4811aio backend. Due to it's currenbt limitations it has to be requested 4858io_uring backend (\f(CW\*(C`EV_USE_EPOLL\*(C'\fR must also be enabled). Due to it's
4812explicitly. If undefined, it will be enabled on linux, otherwise 4859current limitations it has to be requested explicitly. If undefined, it
4813disabled. 4860will be enabled on linux, otherwise disabled.
4814.IP "\s-1EV_USE_KQUEUE\s0" 4 4861.IP "\s-1EV_USE_KQUEUE\s0" 4
4815.IX Item "EV_USE_KQUEUE" 4862.IX Item "EV_USE_KQUEUE"
4816If defined to be \f(CW1\fR, libev will compile in support for the \s-1BSD\s0 style 4863If 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, 4864\&\f(CW\*(C`kqueue\*(C'\fR(2) backend. Its actual availability will be detected at runtime,
4818otherwise another method will be used as fallback. This is the preferred 4865otherwise another method will be used as fallback. This is the preferred
… …
5074in. If set to \f(CW1\fR, then verification code will be compiled in, but not 5121in. If set to \f(CW1\fR, then verification code will be compiled in, but not
5075called. If set to \f(CW2\fR, then the internal verification code will be 5122called. If set to \f(CW2\fR, then the internal verification code will be
5076called once per loop, which can slow down libev. If set to \f(CW3\fR, then the 5123called once per loop, which can slow down libev. If set to \f(CW3\fR, then the
5077verification code will be called very frequently, which will slow down 5124verification code will be called very frequently, which will slow down
5078libev considerably. 5125libev considerably.
5126.Sp
5127Verification errors are reported via C's \f(CW\*(C`assert\*(C'\fR mechanism, so if you
5128disable that (e.g. by defining \f(CW\*(C`NDEBUG\*(C'\fR) then no errors will be reported.
5079.Sp 5129.Sp
5080The default is \f(CW1\fR, unless \f(CW\*(C`EV_FEATURES\*(C'\fR overrides it, in which case it 5130The default is \f(CW1\fR, unless \f(CW\*(C`EV_FEATURES\*(C'\fR overrides it, in which case it
5081will be \f(CW0\fR. 5131will be \f(CW0\fR.
5082.IP "\s-1EV_COMMON\s0" 4 5132.IP "\s-1EV_COMMON\s0" 4
5083.IX Item "EV_COMMON" 5133.IX Item "EV_COMMON"

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