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Comparing libev/ev.pod (file contents):
Revision 1.456 by root, Tue Jul 2 06:07:54 2019 UTC vs.
Revision 1.460 by root, Wed Jan 22 02:00:13 2020 UTC

… …
480unblocking the signals. 480unblocking the signals.
481 481
482It's also required by POSIX in a threaded program, as libev calls 482It's also required by POSIX in a threaded program, as libev calls
483C<sigprocmask>, whose behaviour is officially unspecified. 483C<sigprocmask>, whose behaviour is officially unspecified.
484 484
485This flag's behaviour will become the default in future versions of libev. 485=item C<EVFLAG_NOTIMERFD>
486
487When this flag is specified, the libev will avoid using a C<timerfd> to
488detect time jumps. It will still be able to detect time jumps, but takes
489longer and has a lower accuracy in doing so, but saves a file descriptor
490per loop.
491
492The current implementation only tries to use a C<timerfd> when the first
493C<ev_periodic> watcher is started and falls back on other methods if it
494cannot be created, but this behaviour might change in the future.
486 495
487=item C<EVBACKEND_SELECT> (value 1, portable select backend) 496=item C<EVBACKEND_SELECT> (value 1, portable select backend)
488 497
489This is your standard select(2) backend. Not I<completely> standard, as 498This is your standard select(2) backend. Not I<completely> standard, as
490libev tries to roll its own fd_set with no limits on the number of fds, 499libev tries to roll its own fd_set with no limits on the number of fds,
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1209with a watcher-specific start function (C<< ev_TYPE_start (loop, watcher 1218with a watcher-specific start function (C<< ev_TYPE_start (loop, watcher
1210*) >>), and you can stop watching for events at any time by calling the 1219*) >>), and you can stop watching for events at any time by calling the
1211corresponding stop function (C<< ev_TYPE_stop (loop, watcher *) >>. 1220corresponding stop function (C<< ev_TYPE_stop (loop, watcher *) >>.
1212 1221
1213As long as your watcher is active (has been started but not stopped) you 1222As long as your watcher is active (has been started but not stopped) you
1214must not touch the values stored in it. Most specifically you must never 1223must not touch the values stored in it except when explicitly documented
1215reinitialise it or call its C<ev_TYPE_set> macro. 1224otherwise. Most specifically you must never reinitialise it or call its
1225C<ev_TYPE_set> macro.
1216 1226
1217Each and every callback receives the event loop pointer as first, the 1227Each and every callback receives the event loop pointer as first, the
1218registered watcher structure as second, and a bitset of received events as 1228registered watcher structure as second, and a bitset of received events as
1219third argument. 1229third argument.
1220 1230
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1535 1545
1536Many event loops support I<watcher priorities>, which are usually small 1546Many event loops support I<watcher priorities>, which are usually small
1537integers that influence the ordering of event callback invocation 1547integers that influence the ordering of event callback invocation
1538between watchers in some way, all else being equal. 1548between watchers in some way, all else being equal.
1539 1549
1540In libev, Watcher priorities can be set using C<ev_set_priority>. See its 1550In libev, watcher priorities can be set using C<ev_set_priority>. See its
1541description for the more technical details such as the actual priority 1551description for the more technical details such as the actual priority
1542range. 1552range.
1543 1553
1544There are two common ways how these these priorities are being interpreted 1554There are two common ways how these these priorities are being interpreted
1545by event loops: 1555by event loops:
… …
1639 1649
1640This section describes each watcher in detail, but will not repeat 1650This section describes each watcher in detail, but will not repeat
1641information given in the last section. Any initialisation/set macros, 1651information given in the last section. Any initialisation/set macros,
1642functions and members specific to the watcher type are explained. 1652functions and members specific to the watcher type are explained.
1643 1653
1644Members are additionally marked with either I<[read-only]>, meaning that, 1654Most members are additionally marked with either I<[read-only]>, meaning
1645while the watcher is active, you can look at the member and expect some 1655that, while the watcher is active, you can look at the member and expect
1646sensible content, but you must not modify it (you can modify it while the 1656some sensible content, but you must not modify it (you can modify it while
1647watcher is stopped to your hearts content), or I<[read-write]>, which 1657the watcher is stopped to your hearts content), or I<[read-write]>, which
1648means you can expect it to have some sensible content while the watcher 1658means you can expect it to have some sensible content while the watcher
1649is active, but you can also modify it. Modifying it may not do something 1659is active, but you can also modify it. Modifying it may not do something
1650sensible or take immediate effect (or do anything at all), but libev will 1660sensible or take immediate effect (or do anything at all), but libev will
1651not crash or malfunction in any way. 1661not crash or malfunction in any way.
1652 1662
1663In any case, the documentation for each member will explain what the
1664effects are, and if there are any additional access restrictions.
1653 1665
1654=head2 C<ev_io> - is this file descriptor readable or writable? 1666=head2 C<ev_io> - is this file descriptor readable or writable?
1655 1667
1656I/O watchers check whether a file descriptor is readable or writable 1668I/O watchers check whether a file descriptor is readable or writable
1657in each iteration of the event loop, or, more precisely, when reading 1669in each iteration of the event loop, or, more precisely, when reading
… …
1820 1832
1821Configures an C<ev_io> watcher. The C<fd> is the file descriptor to 1833Configures an C<ev_io> watcher. The C<fd> is the file descriptor to
1822receive events for and C<events> is either C<EV_READ>, C<EV_WRITE> or 1834receive events for and C<events> is either C<EV_READ>, C<EV_WRITE> or
1823C<EV_READ | EV_WRITE>, to express the desire to receive the given events. 1835C<EV_READ | EV_WRITE>, to express the desire to receive the given events.
1824 1836
1825=item int fd [read-only] 1837=item ev_io_modify (ev_io *, int events)
1826 1838
1827The file descriptor being watched. 1839Similar to C<ev_io_set>, but only changes the event mask. Using this might
1840be faster with some backends, as libev can assume that the C<fd> still
1841refers to the same underlying file description, something it cannot do
1842when using C<ev_io_set>.
1828 1843
1844=item int fd [no-modify]
1845
1846The file descriptor being watched. While it can be read at any time, you
1847must not modify this member even when the watcher is stopped - always use
1848C<ev_io_set> for that.
1849
1829=item int events [read-only] 1850=item int events [no-modify]
1830 1851
1831The events being watched. 1852The set of events the fd is being watched for, among other flags. Remember
1853that this is a bit set - to test for C<EV_READ>, use C<< w->events &
1854EV_READ >>, and similarly for C<EV_WRITE>.
1855
1856As with C<fd>, you must not modify this member even when the watcher is
1857stopped, always use C<ev_io_set> or C<ev_io_modify> for that.
1832 1858
1833=back 1859=back
1834 1860
1835=head3 Examples 1861=head3 Examples
1836 1862
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4615available and will probe for kernel support at runtime. This will improve 4641available and will probe for kernel support at runtime. This will improve
4616C<ev_signal> and C<ev_async> performance and reduce resource consumption. 4642C<ev_signal> and C<ev_async> performance and reduce resource consumption.
4617If undefined, it will be enabled if the headers indicate GNU/Linux + Glibc 4643If undefined, it will be enabled if the headers indicate GNU/Linux + Glibc
46182.7 or newer, otherwise disabled. 46442.7 or newer, otherwise disabled.
4619 4645
4646=item EV_USE_SIGNALFD
4647
4648If defined to be C<1>, then libev will assume that C<signalfd ()> is
4649available and will probe for kernel support at runtime. This enables
4650the use of EVFLAG_SIGNALFD for faster and simpler signal handling. If
4651undefined, it will be enabled if the headers indicate GNU/Linux + Glibc
46522.7 or newer, otherwise disabled.
4653
4654=item EV_USE_TIMERFD
4655
4656If defined to be C<1>, then libev will assume that C<timerfd ()> is
4657available and will probe for kernel support at runtime. This allows
4658libev to detect time jumps accurately. If undefined, it will be enabled
4659if the headers indicate GNU/Linux + Glibc 2.8 or newer and define
4660C<TFD_TIMER_CANCEL_ON_SET>, otherwise disabled.
4661
4662=item EV_USE_EVENTFD
4663
4664If defined to be C<1>, then libev will assume that C<eventfd ()> is
4665available and will probe for kernel support at runtime. This will improve
4666C<ev_signal> and C<ev_async> performance and reduce resource consumption.
4667If undefined, it will be enabled if the headers indicate GNU/Linux + Glibc
46682.7 or newer, otherwise disabled.
4669
4620=item EV_USE_SELECT 4670=item EV_USE_SELECT
4621 4671
4622If undefined or defined to be C<1>, libev will compile in support for the 4672If undefined or defined to be C<1>, libev will compile in support for the
4623C<select>(2) backend. No attempt at auto-detection will be done: if no 4673C<select>(2) backend. No attempt at auto-detection will be done: if no
4624other method takes over, select will be it. Otherwise the select backend 4674other method takes over, select will be it. Otherwise the select backend

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