… | |
… | |
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 "2020-03-12" "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" |
… | |
… | |
606 | 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 |
607 | unblocking the signals. |
607 | unblocking the signals. |
608 | .Sp |
608 | .Sp |
609 | 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 |
610 | \&\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 |
|
|
615 | detect time jumps. It will still be able to detect time jumps, but takes |
|
|
616 | longer and has a lower accuracy in doing so, but saves a file descriptor |
|
|
617 | per loop. |
611 | .Sp |
618 | .Sp |
612 | 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 |
|
|
621 | cannot be created, but this behaviour might change in the future. |
613 | .ie n .IP """EVBACKEND_SELECT"" (value 1, portable select backend)" 4 |
622 | .ie n .IP """EVBACKEND_SELECT"" (value 1, portable select backend)" 4 |
614 | .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 |
615 | .IX Item "EVBACKEND_SELECT (value 1, portable select backend)" |
624 | .IX Item "EVBACKEND_SELECT (value 1, portable select backend)" |
616 | 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 |
617 | 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, |
… | |
… | |
1340 | with a watcher-specific start function (\f(CW\*(C`ev_TYPE_start (loop, watcher |
1349 | with a watcher-specific start function (\f(CW\*(C`ev_TYPE_start (loop, watcher |
1341 | *)\*(C'\fR), and you can stop watching for events at any time by calling the |
1350 | *)\*(C'\fR), and you can stop watching for events at any time by calling the |
1342 | corresponding stop function (\f(CW\*(C`ev_TYPE_stop (loop, watcher *)\*(C'\fR. |
1351 | corresponding stop function (\f(CW\*(C`ev_TYPE_stop (loop, watcher *)\*(C'\fR. |
1343 | .PP |
1352 | .PP |
1344 | As long as your watcher is active (has been started but not stopped) you |
1353 | As long as your watcher is active (has been started but not stopped) you |
1345 | must not touch the values stored in it. Most specifically you must never |
1354 | must not touch the values stored in it except when explicitly documented |
1346 | reinitialise it or call its \f(CW\*(C`ev_TYPE_set\*(C'\fR macro. |
1355 | otherwise. Most specifically you must never reinitialise it or call its |
|
|
1356 | \&\f(CW\*(C`ev_TYPE_set\*(C'\fR macro. |
1347 | .PP |
1357 | .PP |
1348 | Each and every callback receives the event loop pointer as first, the |
1358 | Each and every callback receives the event loop pointer as first, the |
1349 | registered watcher structure as second, and a bitset of received events as |
1359 | registered watcher structure as second, and a bitset of received events as |
1350 | third argument. |
1360 | third argument. |
1351 | .PP |
1361 | .PP |
… | |
… | |
1654 | .IX Subsection "WATCHER PRIORITY MODELS" |
1664 | .IX Subsection "WATCHER PRIORITY MODELS" |
1655 | Many event loops support \fIwatcher priorities\fR, which are usually small |
1665 | Many event loops support \fIwatcher priorities\fR, which are usually small |
1656 | integers that influence the ordering of event callback invocation |
1666 | integers that influence the ordering of event callback invocation |
1657 | between watchers in some way, all else being equal. |
1667 | between watchers in some way, all else being equal. |
1658 | .PP |
1668 | .PP |
1659 | In libev, Watcher priorities can be set using \f(CW\*(C`ev_set_priority\*(C'\fR. See its |
1669 | In libev, watcher priorities can be set using \f(CW\*(C`ev_set_priority\*(C'\fR. See its |
1660 | description for the more technical details such as the actual priority |
1670 | description for the more technical details such as the actual priority |
1661 | range. |
1671 | range. |
1662 | .PP |
1672 | .PP |
1663 | There are two common ways how these these priorities are being interpreted |
1673 | There are two common ways how these these priorities are being interpreted |
1664 | by event loops: |
1674 | by event loops: |
… | |
… | |
1758 | .IX Header "WATCHER TYPES" |
1768 | .IX Header "WATCHER TYPES" |
1759 | This section describes each watcher in detail, but will not repeat |
1769 | This section describes each watcher in detail, but will not repeat |
1760 | information given in the last section. Any initialisation/set macros, |
1770 | information given in the last section. Any initialisation/set macros, |
1761 | functions and members specific to the watcher type are explained. |
1771 | functions and members specific to the watcher type are explained. |
1762 | .PP |
1772 | .PP |
1763 | Members are additionally marked with either \fI[read\-only]\fR, meaning that, |
1773 | Most members are additionally marked with either \fI[read\-only]\fR, meaning |
1764 | while the watcher is active, you can look at the member and expect some |
1774 | that, while the watcher is active, you can look at the member and expect |
1765 | sensible content, but you must not modify it (you can modify it while the |
1775 | some sensible content, but you must not modify it (you can modify it while |
1766 | watcher is stopped to your hearts content), or \fI[read\-write]\fR, which |
1776 | the watcher is stopped to your hearts content), or \fI[read\-write]\fR, which |
1767 | means you can expect it to have some sensible content while the watcher |
1777 | means you can expect it to have some sensible content while the watcher is |
1768 | is active, but you can also modify it. Modifying it may not do something |
1778 | active, but you can also modify it (within the same thread as the event |
|
|
1779 | loop, i.e. without creating data races). Modifying it may not do something |
1769 | sensible or take immediate effect (or do anything at all), but libev will |
1780 | sensible or take immediate effect (or do anything at all), but libev will |
1770 | not crash or malfunction in any way. |
1781 | not crash or malfunction in any way. |
|
|
1782 | .PP |
|
|
1783 | In any case, the documentation for each member will explain what the |
|
|
1784 | effects are, and if there are any additional access restrictions. |
1771 | .ie n .SS """ev_io"" \- is this file descriptor readable or writable?" |
1785 | .ie n .SS """ev_io"" \- is this file descriptor readable or writable?" |
1772 | .el .SS "\f(CWev_io\fP \- is this file descriptor readable or writable?" |
1786 | .el .SS "\f(CWev_io\fP \- is this file descriptor readable or writable?" |
1773 | .IX Subsection "ev_io - is this file descriptor readable or writable?" |
1787 | .IX Subsection "ev_io - is this file descriptor readable or writable?" |
1774 | I/O watchers check whether a file descriptor is readable or writable |
1788 | I/O watchers check whether a file descriptor is readable or writable |
1775 | in each iteration of the event loop, or, more precisely, when reading |
1789 | in each iteration of the event loop, or, more precisely, when reading |
… | |
… | |
1871 | reuse the same code path. |
1885 | reuse the same code path. |
1872 | .PP |
1886 | .PP |
1873 | \fIThe special problem of fork\fR |
1887 | \fIThe special problem of fork\fR |
1874 | .IX Subsection "The special problem of fork" |
1888 | .IX Subsection "The special problem of fork" |
1875 | .PP |
1889 | .PP |
1876 | Some backends (epoll, kqueue, probably linuxaio) do not support \f(CW\*(C`fork ()\*(C'\fR |
1890 | Some backends (epoll, kqueue, linuxaio, iouring) do not support \f(CW\*(C`fork ()\*(C'\fR |
1877 | at all or exhibit useless behaviour. Libev fully supports fork, but needs |
1891 | at all or exhibit useless behaviour. Libev fully supports fork, but needs |
1878 | to be told about it in the child if you want to continue to use it in the |
1892 | to be told about it in the child if you want to continue to use it in the |
1879 | child. |
1893 | child. |
1880 | .PP |
1894 | .PP |
1881 | To support fork in your child processes, you have to call \f(CW\*(C`ev_loop_fork |
1895 | To support fork in your child processes, you have to call \f(CW\*(C`ev_loop_fork |
… | |
… | |
1941 | .PD 0 |
1955 | .PD 0 |
1942 | .IP "ev_io_set (ev_io *, int fd, int events)" 4 |
1956 | .IP "ev_io_set (ev_io *, int fd, int events)" 4 |
1943 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
1957 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
1944 | .PD |
1958 | .PD |
1945 | Configures an \f(CW\*(C`ev_io\*(C'\fR watcher. The \f(CW\*(C`fd\*(C'\fR is the file descriptor to |
1959 | Configures an \f(CW\*(C`ev_io\*(C'\fR watcher. The \f(CW\*(C`fd\*(C'\fR is the file descriptor to |
1946 | receive events for and \f(CW\*(C`events\*(C'\fR is either \f(CW\*(C`EV_READ\*(C'\fR, \f(CW\*(C`EV_WRITE\*(C'\fR or |
1960 | receive events for and \f(CW\*(C`events\*(C'\fR is either \f(CW\*(C`EV_READ\*(C'\fR, \f(CW\*(C`EV_WRITE\*(C'\fR, both |
1947 | \&\f(CW\*(C`EV_READ | EV_WRITE\*(C'\fR, to express the desire to receive the given events. |
1961 | \&\f(CW\*(C`EV_READ | EV_WRITE\*(C'\fR or \f(CW0\fR, to express the desire to receive the given |
|
|
1962 | events. |
|
|
1963 | .Sp |
|
|
1964 | Note that setting the \f(CW\*(C`events\*(C'\fR to \f(CW0\fR and starting the watcher is |
|
|
1965 | supported, but not specially optimized \- if your program sometimes happens |
|
|
1966 | to generate this combination this is fine, but if it is easy to avoid |
|
|
1967 | starting an io watcher watching for no events you should do so. |
|
|
1968 | .IP "ev_io_modify (ev_io *, int events)" 4 |
|
|
1969 | .IX Item "ev_io_modify (ev_io *, int events)" |
|
|
1970 | Similar to \f(CW\*(C`ev_io_set\*(C'\fR, but only changes the requested events. Using this |
|
|
1971 | might be faster with some backends, as libev can assume that the \f(CW\*(C`fd\*(C'\fR |
|
|
1972 | still refers to the same underlying file description, something it cannot |
|
|
1973 | do when using \f(CW\*(C`ev_io_set\*(C'\fR. |
1948 | .IP "int fd [read\-only]" 4 |
1974 | .IP "int fd [no\-modify]" 4 |
1949 | .IX Item "int fd [read-only]" |
1975 | .IX Item "int fd [no-modify]" |
1950 | The file descriptor being watched. |
1976 | The file descriptor being watched. While it can be read at any time, you |
|
|
1977 | must not modify this member even when the watcher is stopped \- always use |
|
|
1978 | \&\f(CW\*(C`ev_io_set\*(C'\fR for that. |
1951 | .IP "int events [read\-only]" 4 |
1979 | .IP "int events [no\-modify]" 4 |
1952 | .IX Item "int events [read-only]" |
1980 | .IX Item "int events [no-modify]" |
1953 | The events being watched. |
1981 | The set of events the fd is being watched for, among other flags. Remember |
|
|
1982 | that this is a bit set \- to test for \f(CW\*(C`EV_READ\*(C'\fR, use \f(CW\*(C`w\->events & |
|
|
1983 | EV_READ\*(C'\fR, and similarly for \f(CW\*(C`EV_WRITE\*(C'\fR. |
|
|
1984 | .Sp |
|
|
1985 | As with \f(CW\*(C`fd\*(C'\fR, you must not modify this member even when the watcher is |
|
|
1986 | stopped, always use \f(CW\*(C`ev_io_set\*(C'\fR or \f(CW\*(C`ev_io_modify\*(C'\fR for that. |
1954 | .PP |
1987 | .PP |
1955 | \fIExamples\fR |
1988 | \fIExamples\fR |
1956 | .IX Subsection "Examples" |
1989 | .IX Subsection "Examples" |
1957 | .PP |
1990 | .PP |
1958 | Example: Call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well |
1991 | Example: Call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well |
… | |
… | |
4386 | gets automatically stopped and restarted when reconfiguring it with this |
4419 | gets automatically stopped and restarted when reconfiguring it with this |
4387 | method. |
4420 | method. |
4388 | .Sp |
4421 | .Sp |
4389 | For \f(CW\*(C`ev::embed\*(C'\fR watchers this method is called \f(CW\*(C`set_embed\*(C'\fR, to avoid |
4422 | For \f(CW\*(C`ev::embed\*(C'\fR watchers this method is called \f(CW\*(C`set_embed\*(C'\fR, to avoid |
4390 | clashing with the \f(CW\*(C`set (loop)\*(C'\fR method. |
4423 | clashing with the \f(CW\*(C`set (loop)\*(C'\fR method. |
|
|
4424 | .Sp |
|
|
4425 | For \f(CW\*(C`ev::io\*(C'\fR watchers there is an additional \f(CW\*(C`set\*(C'\fR method that acepts a |
|
|
4426 | new event mask only, and internally calls \f(CW\*(C`ev_io_modfify\*(C'\fR. |
4391 | .IP "w\->start ()" 4 |
4427 | .IP "w\->start ()" 4 |
4392 | .IX Item "w->start ()" |
4428 | .IX Item "w->start ()" |
4393 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument, as the |
4429 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument, as the |
4394 | constructor already stores the event loop. |
4430 | constructor already stores the event loop. |
4395 | .IP "w\->start ([arguments])" 4 |
4431 | .IP "w\->start ([arguments])" 4 |
… | |
… | |
4624 | \& |
4660 | \& |
4625 | \& ev_select.c only when select backend is enabled |
4661 | \& ev_select.c only when select backend is enabled |
4626 | \& ev_poll.c only when poll backend is enabled |
4662 | \& ev_poll.c only when poll backend is enabled |
4627 | \& ev_epoll.c only when the epoll backend is enabled |
4663 | \& ev_epoll.c only when the epoll backend is enabled |
4628 | \& ev_linuxaio.c only when the linux aio backend is enabled |
4664 | \& ev_linuxaio.c only when the linux aio backend is enabled |
|
|
4665 | \& ev_iouring.c only when the linux io_uring backend is enabled |
4629 | \& ev_kqueue.c only when the kqueue backend is enabled |
4666 | \& ev_kqueue.c only when the kqueue backend is enabled |
4630 | \& ev_port.c only when the solaris port backend is enabled |
4667 | \& ev_port.c only when the solaris port backend is enabled |
4631 | .Ve |
4668 | .Ve |
4632 | .PP |
4669 | .PP |
4633 | \&\fIev.c\fR includes the backend files directly when enabled, so you only need |
4670 | \&\fIev.c\fR includes the backend files directly when enabled, so you only need |
… | |
… | |
4746 | higher, as it simplifies linking (no need for \f(CW\*(C`\-lrt\*(C'\fR). |
4783 | higher, as it simplifies linking (no need for \f(CW\*(C`\-lrt\*(C'\fR). |
4747 | .IP "\s-1EV_USE_NANOSLEEP\s0" 4 |
4784 | .IP "\s-1EV_USE_NANOSLEEP\s0" 4 |
4748 | .IX Item "EV_USE_NANOSLEEP" |
4785 | .IX Item "EV_USE_NANOSLEEP" |
4749 | If defined to be \f(CW1\fR, libev will assume that \f(CW\*(C`nanosleep ()\*(C'\fR is available |
4786 | If defined to be \f(CW1\fR, libev will assume that \f(CW\*(C`nanosleep ()\*(C'\fR is available |
4750 | and will use it for delays. Otherwise it will use \f(CW\*(C`select ()\*(C'\fR. |
4787 | and will use it for delays. Otherwise it will use \f(CW\*(C`select ()\*(C'\fR. |
|
|
4788 | .IP "\s-1EV_USE_EVENTFD\s0" 4 |
|
|
4789 | .IX Item "EV_USE_EVENTFD" |
|
|
4790 | If defined to be \f(CW1\fR, then libev will assume that \f(CW\*(C`eventfd ()\*(C'\fR is |
|
|
4791 | available and will probe for kernel support at runtime. This will improve |
|
|
4792 | \&\f(CW\*(C`ev_signal\*(C'\fR and \f(CW\*(C`ev_async\*(C'\fR performance and reduce resource consumption. |
|
|
4793 | If undefined, it will be enabled if the headers indicate GNU/Linux + Glibc |
|
|
4794 | 2.7 or newer, otherwise disabled. |
|
|
4795 | .IP "\s-1EV_USE_SIGNALFD\s0" 4 |
|
|
4796 | .IX Item "EV_USE_SIGNALFD" |
|
|
4797 | If defined to be \f(CW1\fR, then libev will assume that \f(CW\*(C`signalfd ()\*(C'\fR is |
|
|
4798 | available and will probe for kernel support at runtime. This enables |
|
|
4799 | the use of \s-1EVFLAG_SIGNALFD\s0 for faster and simpler signal handling. If |
|
|
4800 | undefined, it will be enabled if the headers indicate GNU/Linux + Glibc |
|
|
4801 | 2.7 or newer, otherwise disabled. |
|
|
4802 | .IP "\s-1EV_USE_TIMERFD\s0" 4 |
|
|
4803 | .IX Item "EV_USE_TIMERFD" |
|
|
4804 | If defined to be \f(CW1\fR, then libev will assume that \f(CW\*(C`timerfd ()\*(C'\fR is |
|
|
4805 | available and will probe for kernel support at runtime. This allows |
|
|
4806 | libev to detect time jumps accurately. If undefined, it will be enabled |
|
|
4807 | if the headers indicate GNU/Linux + Glibc 2.8 or newer and define |
|
|
4808 | \&\f(CW\*(C`TFD_TIMER_CANCEL_ON_SET\*(C'\fR, otherwise disabled. |
4751 | .IP "\s-1EV_USE_EVENTFD\s0" 4 |
4809 | .IP "\s-1EV_USE_EVENTFD\s0" 4 |
4752 | .IX Item "EV_USE_EVENTFD" |
4810 | .IX Item "EV_USE_EVENTFD" |
4753 | If defined to be \f(CW1\fR, then libev will assume that \f(CW\*(C`eventfd ()\*(C'\fR is |
4811 | If defined to be \f(CW1\fR, then libev will assume that \f(CW\*(C`eventfd ()\*(C'\fR is |
4754 | available and will probe for kernel support at runtime. This will improve |
4812 | available and will probe for kernel support at runtime. This will improve |
4755 | \&\f(CW\*(C`ev_signal\*(C'\fR and \f(CW\*(C`ev_async\*(C'\fR performance and reduce resource consumption. |
4813 | \&\f(CW\*(C`ev_signal\*(C'\fR and \f(CW\*(C`ev_async\*(C'\fR performance and reduce resource consumption. |
… | |
… | |
4816 | otherwise another method will be used as fallback. This is the preferred |
4874 | otherwise another method will be used as fallback. This is the preferred |
4817 | backend for GNU/Linux systems. If undefined, it will be enabled if the |
4875 | backend for GNU/Linux systems. If undefined, it will be enabled if the |
4818 | headers indicate GNU/Linux + Glibc 2.4 or newer, otherwise disabled. |
4876 | headers indicate GNU/Linux + Glibc 2.4 or newer, otherwise disabled. |
4819 | .IP "\s-1EV_USE_LINUXAIO\s0" 4 |
4877 | .IP "\s-1EV_USE_LINUXAIO\s0" 4 |
4820 | .IX Item "EV_USE_LINUXAIO" |
4878 | .IX Item "EV_USE_LINUXAIO" |
|
|
4879 | If defined to be \f(CW1\fR, libev will compile in support for the Linux aio |
|
|
4880 | backend (\f(CW\*(C`EV_USE_EPOLL\*(C'\fR must also be enabled). If undefined, it will be |
|
|
4881 | enabled on linux, otherwise disabled. |
|
|
4882 | .IP "\s-1EV_USE_IOURING\s0" 4 |
|
|
4883 | .IX Item "EV_USE_IOURING" |
4821 | If defined to be \f(CW1\fR, libev will compile in support for the Linux |
4884 | If defined to be \f(CW1\fR, libev will compile in support for the Linux |
4822 | aio backend. Due to it's currenbt limitations it has to be requested |
4885 | io_uring backend (\f(CW\*(C`EV_USE_EPOLL\*(C'\fR must also be enabled). Due to it's |
4823 | explicitly. If undefined, it will be enabled on linux, otherwise |
4886 | current limitations it has to be requested explicitly. If undefined, it |
4824 | disabled. |
4887 | will be enabled on linux, otherwise disabled. |
4825 | .IP "\s-1EV_USE_KQUEUE\s0" 4 |
4888 | .IP "\s-1EV_USE_KQUEUE\s0" 4 |
4826 | .IX Item "EV_USE_KQUEUE" |
4889 | .IX Item "EV_USE_KQUEUE" |
4827 | If defined to be \f(CW1\fR, libev will compile in support for the \s-1BSD\s0 style |
4890 | If defined to be \f(CW1\fR, libev will compile in support for the \s-1BSD\s0 style |
4828 | \&\f(CW\*(C`kqueue\*(C'\fR(2) backend. Its actual availability will be detected at runtime, |
4891 | \&\f(CW\*(C`kqueue\*(C'\fR(2) backend. Its actual availability will be detected at runtime, |
4829 | otherwise another method will be used as fallback. This is the preferred |
4892 | otherwise another method will be used as fallback. This is the preferred |