… | |
… | |
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 "2019-06-25" "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" |
… | |
… | |
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 |
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297 | consistency checking code inside libev that can be used to check for |
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298 | internal inconsistencies, suually caused by application bugs. |
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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 |
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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 |
… | |
… | |
602 | want to handle signals only in specific threads and want to avoid libev |
606 | want to handle signals only in specific threads and want to avoid libev |
603 | unblocking the signals. |
607 | unblocking the signals. |
604 | .Sp |
608 | .Sp |
605 | It's also required by \s-1POSIX\s0 in a threaded program, as libev calls |
609 | It'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" |
|
|
614 | When this flag is specified, the libev will avoid using a \f(CW\*(C`timerfd\*(C'\fR to |
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|
615 | detect time jumps. It will still be able to detect time jumps, but takes |
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|
616 | longer and has a lower accuracy in doing so, but saves a file descriptor |
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|
617 | per loop. |
607 | .Sp |
618 | .Sp |
608 | This flag's behaviour will become the default in future versions of libev. |
619 | The 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 |
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|
621 | cannot 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)" |
612 | This is your standard \fBselect\fR\|(2) backend. Not \fIcompletely\fR standard, as |
625 | This is your standard \fBselect\fR\|(2) backend. Not \fIcompletely\fR standard, as |
613 | libev tries to roll its own fd_set with no limits on the number of fds, |
626 | libev tries to roll its own fd_set with no limits on the number of fds, |
… | |
… | |
1650 | .IX Subsection "WATCHER PRIORITY MODELS" |
1663 | .IX Subsection "WATCHER PRIORITY MODELS" |
1651 | Many event loops support \fIwatcher priorities\fR, which are usually small |
1664 | Many event loops support \fIwatcher priorities\fR, which are usually small |
1652 | integers that influence the ordering of event callback invocation |
1665 | integers that influence the ordering of event callback invocation |
1653 | between watchers in some way, all else being equal. |
1666 | between watchers in some way, all else being equal. |
1654 | .PP |
1667 | .PP |
1655 | In libev, Watcher priorities can be set using \f(CW\*(C`ev_set_priority\*(C'\fR. See its |
1668 | In libev, watcher priorities can be set using \f(CW\*(C`ev_set_priority\*(C'\fR. See its |
1656 | description for the more technical details such as the actual priority |
1669 | description for the more technical details such as the actual priority |
1657 | range. |
1670 | range. |
1658 | .PP |
1671 | .PP |
1659 | There are two common ways how these these priorities are being interpreted |
1672 | There are two common ways how these these priorities are being interpreted |
1660 | by event loops: |
1673 | by event loops: |
… | |
… | |
1867 | reuse the same code path. |
1880 | reuse the same code path. |
1868 | .PP |
1881 | .PP |
1869 | \fIThe special problem of fork\fR |
1882 | \fIThe special problem of fork\fR |
1870 | .IX Subsection "The special problem of fork" |
1883 | .IX Subsection "The special problem of fork" |
1871 | .PP |
1884 | .PP |
1872 | Some backends (epoll, kqueue, probably linuxaio) do not support \f(CW\*(C`fork ()\*(C'\fR |
1885 | Some backends (epoll, kqueue, linuxaio, iouring) do not support \f(CW\*(C`fork ()\*(C'\fR |
1873 | at all or exhibit useless behaviour. Libev fully supports fork, but needs |
1886 | at all or exhibit useless behaviour. Libev fully supports fork, but needs |
1874 | to be told about it in the child if you want to continue to use it in the |
1887 | to be told about it in the child if you want to continue to use it in the |
1875 | child. |
1888 | child. |
1876 | .PP |
1889 | .PP |
1877 | To support fork in your child processes, you have to call \f(CW\*(C`ev_loop_fork |
1890 | To support fork in your child processes, you have to call \f(CW\*(C`ev_loop_fork |
… | |
… | |
4620 | \& |
4633 | \& |
4621 | \& ev_select.c only when select backend is enabled |
4634 | \& ev_select.c only when select backend is enabled |
4622 | \& ev_poll.c only when poll backend is enabled |
4635 | \& ev_poll.c only when poll backend is enabled |
4623 | \& ev_epoll.c only when the epoll backend is enabled |
4636 | \& ev_epoll.c only when the epoll backend is enabled |
4624 | \& 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 |
4625 | \& ev_kqueue.c only when the kqueue backend is enabled |
4639 | \& ev_kqueue.c only when the kqueue backend is enabled |
4626 | \& ev_port.c only when the solaris port backend is enabled |
4640 | \& ev_port.c only when the solaris port backend is enabled |
4627 | .Ve |
4641 | .Ve |
4628 | .PP |
4642 | .PP |
4629 | \&\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 |
… | |
… | |
4742 | higher, as it simplifies linking (no need for \f(CW\*(C`\-lrt\*(C'\fR). |
4756 | higher, as it simplifies linking (no need for \f(CW\*(C`\-lrt\*(C'\fR). |
4743 | .IP "\s-1EV_USE_NANOSLEEP\s0" 4 |
4757 | .IP "\s-1EV_USE_NANOSLEEP\s0" 4 |
4744 | .IX Item "EV_USE_NANOSLEEP" |
4758 | .IX Item "EV_USE_NANOSLEEP" |
4745 | If defined to be \f(CW1\fR, libev will assume that \f(CW\*(C`nanosleep ()\*(C'\fR is available |
4759 | If defined to be \f(CW1\fR, libev will assume that \f(CW\*(C`nanosleep ()\*(C'\fR is available |
4746 | and will use it for delays. Otherwise it will use \f(CW\*(C`select ()\*(C'\fR. |
4760 | and 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" |
|
|
4763 | If defined to be \f(CW1\fR, then libev will assume that \f(CW\*(C`eventfd ()\*(C'\fR is |
|
|
4764 | available 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. |
|
|
4766 | If undefined, it will be enabled if the headers indicate GNU/Linux + Glibc |
|
|
4767 | 2.7 or newer, otherwise disabled. |
|
|
4768 | .IP "\s-1EV_USE_SIGNALFD\s0" 4 |
|
|
4769 | .IX Item "EV_USE_SIGNALFD" |
|
|
4770 | If defined to be \f(CW1\fR, then libev will assume that \f(CW\*(C`signalfd ()\*(C'\fR is |
|
|
4771 | available and will probe for kernel support at runtime. This enables |
|
|
4772 | the use of \s-1EVFLAG_SIGNALFD\s0 for faster and simpler signal handling. If |
|
|
4773 | undefined, it will be enabled if the headers indicate GNU/Linux + Glibc |
|
|
4774 | 2.7 or newer, otherwise disabled. |
|
|
4775 | .IP "\s-1EV_USE_TIMERFD\s0" 4 |
|
|
4776 | .IX Item "EV_USE_TIMERFD" |
|
|
4777 | If defined to be \f(CW1\fR, then libev will assume that \f(CW\*(C`timerfd ()\*(C'\fR is |
|
|
4778 | available and will probe for kernel support at runtime. This allows |
|
|
4779 | libev to detect time jumps accurately. If undefined, it will be enabled |
|
|
4780 | if 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. |
4747 | .IP "\s-1EV_USE_EVENTFD\s0" 4 |
4782 | .IP "\s-1EV_USE_EVENTFD\s0" 4 |
4748 | .IX Item "EV_USE_EVENTFD" |
4783 | .IX Item "EV_USE_EVENTFD" |
4749 | If defined to be \f(CW1\fR, then libev will assume that \f(CW\*(C`eventfd ()\*(C'\fR is |
4784 | If defined to be \f(CW1\fR, then libev will assume that \f(CW\*(C`eventfd ()\*(C'\fR is |
4750 | available and will probe for kernel support at runtime. This will improve |
4785 | available and will probe for kernel support at runtime. This will improve |
4751 | \&\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. |
… | |
… | |
4812 | otherwise another method will be used as fallback. This is the preferred |
4847 | otherwise another method will be used as fallback. This is the preferred |
4813 | backend for GNU/Linux systems. If undefined, it will be enabled if the |
4848 | backend for GNU/Linux systems. If undefined, it will be enabled if the |
4814 | headers indicate GNU/Linux + Glibc 2.4 or newer, otherwise disabled. |
4849 | headers indicate GNU/Linux + Glibc 2.4 or newer, otherwise disabled. |
4815 | .IP "\s-1EV_USE_LINUXAIO\s0" 4 |
4850 | .IP "\s-1EV_USE_LINUXAIO\s0" 4 |
4816 | .IX Item "EV_USE_LINUXAIO" |
4851 | .IX Item "EV_USE_LINUXAIO" |
|
|
4852 | If defined to be \f(CW1\fR, libev will compile in support for the Linux aio |
|
|
4853 | backend (\f(CW\*(C`EV_USE_EPOLL\*(C'\fR must also be enabled). If undefined, it will be |
|
|
4854 | enabled on linux, otherwise disabled. |
|
|
4855 | .IP "\s-1EV_USE_IOURING\s0" 4 |
|
|
4856 | .IX Item "EV_USE_IOURING" |
4817 | If defined to be \f(CW1\fR, libev will compile in support for the Linux |
4857 | If defined to be \f(CW1\fR, libev will compile in support for the Linux |
4818 | aio backend. Due to it's currenbt limitations it has to be requested |
4858 | io_uring backend (\f(CW\*(C`EV_USE_EPOLL\*(C'\fR must also be enabled). Due to it's |
4819 | explicitly. If undefined, it will be enabled on linux, otherwise |
4859 | current limitations it has to be requested explicitly. If undefined, it |
4820 | disabled. |
4860 | will be enabled on linux, otherwise disabled. |
4821 | .IP "\s-1EV_USE_KQUEUE\s0" 4 |
4861 | .IP "\s-1EV_USE_KQUEUE\s0" 4 |
4822 | .IX Item "EV_USE_KQUEUE" |
4862 | .IX Item "EV_USE_KQUEUE" |
4823 | If defined to be \f(CW1\fR, libev will compile in support for the \s-1BSD\s0 style |
4863 | If defined to be \f(CW1\fR, libev will compile in support for the \s-1BSD\s0 style |
4824 | \&\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, |
4825 | otherwise another method will be used as fallback. This is the preferred |
4865 | otherwise another method will be used as fallback. This is the preferred |
… | |
… | |
5081 | in. If set to \f(CW1\fR, then verification code will be compiled in, but not |
5121 | in. If set to \f(CW1\fR, then verification code will be compiled in, but not |
5082 | called. If set to \f(CW2\fR, then the internal verification code will be |
5122 | called. If set to \f(CW2\fR, then the internal verification code will be |
5083 | called once per loop, which can slow down libev. If set to \f(CW3\fR, then the |
5123 | called once per loop, which can slow down libev. If set to \f(CW3\fR, then the |
5084 | verification code will be called very frequently, which will slow down |
5124 | verification code will be called very frequently, which will slow down |
5085 | libev considerably. |
5125 | libev considerably. |
|
|
5126 | .Sp |
|
|
5127 | Verification errors are reported via C's \f(CW\*(C`assert\*(C'\fR mechanism, so if you |
|
|
5128 | disable that (e.g. by defining \f(CW\*(C`NDEBUG\*(C'\fR) then no errors will be reported. |
5086 | .Sp |
5129 | .Sp |
5087 | The default is \f(CW1\fR, unless \f(CW\*(C`EV_FEATURES\*(C'\fR overrides it, in which case it |
5130 | The default is \f(CW1\fR, unless \f(CW\*(C`EV_FEATURES\*(C'\fR overrides it, in which case it |
5088 | will be \f(CW0\fR. |
5131 | will be \f(CW0\fR. |
5089 | .IP "\s-1EV_COMMON\s0" 4 |
5132 | .IP "\s-1EV_COMMON\s0" 4 |
5090 | .IX Item "EV_COMMON" |
5133 | .IX Item "EV_COMMON" |