… | |
… | |
159 | When libev detects a usage error such as a negative timer interval, then |
159 | When libev detects a usage error such as a negative timer interval, then |
160 | it will print a diagnostic message and abort (via the C<assert> mechanism, |
160 | it will print a diagnostic message and abort (via the C<assert> mechanism, |
161 | so C<NDEBUG> will disable this checking): these are programming errors in |
161 | so C<NDEBUG> will disable this checking): these are programming errors in |
162 | the libev caller and need to be fixed there. |
162 | the libev caller and need to be fixed there. |
163 | |
163 | |
|
|
164 | Via the C<EV_FREQUENT> macro you can compile in and/or enable extensive |
|
|
165 | consistency checking code inside libev that can be used to check for |
|
|
166 | internal inconsistencies, suually caused by application bugs. |
|
|
167 | |
164 | Libev also has a few internal error-checking C<assert>ions, and also has |
168 | Libev also has a few internal error-checking C<assert>ions. These do not |
165 | extensive consistency checking code. These do not trigger under normal |
|
|
166 | circumstances, as they indicate either a bug in libev or worse. |
169 | trigger under normal circumstances, as they indicate either a bug in libev |
|
|
170 | or worse. |
167 | |
171 | |
168 | |
172 | |
169 | =head1 GLOBAL FUNCTIONS |
173 | =head1 GLOBAL FUNCTIONS |
170 | |
174 | |
171 | These functions can be called anytime, even before initialising the |
175 | These functions can be called anytime, even before initialising the |
… | |
… | |
476 | unblocking the signals. |
480 | unblocking the signals. |
477 | |
481 | |
478 | It's also required by POSIX in a threaded program, as libev calls |
482 | It's also required by POSIX in a threaded program, as libev calls |
479 | C<sigprocmask>, whose behaviour is officially unspecified. |
483 | C<sigprocmask>, whose behaviour is officially unspecified. |
480 | |
484 | |
481 | This flag's behaviour will become the default in future versions of libev. |
485 | =item C<EVFLAG_NOTIMERFD> |
|
|
486 | |
|
|
487 | When this flag is specified, the libev will avoid using a C<timerfd> to |
|
|
488 | detect time jumps. It will still be able to detect time jumps, but takes |
|
|
489 | longer and has a lower accuracy in doing so, but saves a file descriptor |
|
|
490 | per loop. |
|
|
491 | |
|
|
492 | The current implementation only tries to use a C<timerfd> when the first |
|
|
493 | C<ev_periodic> watcher is started and falls back on other methods if it |
|
|
494 | cannot be created, but this behaviour might change in the future. |
482 | |
495 | |
483 | =item C<EVBACKEND_SELECT> (value 1, portable select backend) |
496 | =item C<EVBACKEND_SELECT> (value 1, portable select backend) |
484 | |
497 | |
485 | This is your standard select(2) backend. Not I<completely> standard, as |
498 | This is your standard select(2) backend. Not I<completely> standard, as |
486 | libev tries to roll its own fd_set with no limits on the number of fds, |
499 | libev tries to roll its own fd_set with no limits on the number of fds, |
… | |
… | |
1205 | with a watcher-specific start function (C<< ev_TYPE_start (loop, watcher |
1218 | with a watcher-specific start function (C<< ev_TYPE_start (loop, watcher |
1206 | *) >>), 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 |
1207 | corresponding stop function (C<< ev_TYPE_stop (loop, watcher *) >>. |
1220 | corresponding stop function (C<< ev_TYPE_stop (loop, watcher *) >>. |
1208 | |
1221 | |
1209 | As long as your watcher is active (has been started but not stopped) you |
1222 | As long as your watcher is active (has been started but not stopped) you |
1210 | must not touch the values stored in it. Most specifically you must never |
1223 | must not touch the values stored in it except when explicitly documented |
1211 | reinitialise it or call its C<ev_TYPE_set> macro. |
1224 | otherwise. Most specifically you must never reinitialise it or call its |
|
|
1225 | C<ev_TYPE_set> macro. |
1212 | |
1226 | |
1213 | Each and every callback receives the event loop pointer as first, the |
1227 | Each and every callback receives the event loop pointer as first, the |
1214 | registered watcher structure as second, and a bitset of received events as |
1228 | registered watcher structure as second, and a bitset of received events as |
1215 | third argument. |
1229 | third argument. |
1216 | |
1230 | |
… | |
… | |
1531 | |
1545 | |
1532 | Many event loops support I<watcher priorities>, which are usually small |
1546 | Many event loops support I<watcher priorities>, which are usually small |
1533 | integers that influence the ordering of event callback invocation |
1547 | integers that influence the ordering of event callback invocation |
1534 | between watchers in some way, all else being equal. |
1548 | between watchers in some way, all else being equal. |
1535 | |
1549 | |
1536 | In libev, Watcher priorities can be set using C<ev_set_priority>. See its |
1550 | In libev, watcher priorities can be set using C<ev_set_priority>. See its |
1537 | description for the more technical details such as the actual priority |
1551 | description for the more technical details such as the actual priority |
1538 | range. |
1552 | range. |
1539 | |
1553 | |
1540 | There are two common ways how these these priorities are being interpreted |
1554 | There are two common ways how these these priorities are being interpreted |
1541 | by event loops: |
1555 | by event loops: |
… | |
… | |
1635 | |
1649 | |
1636 | This section describes each watcher in detail, but will not repeat |
1650 | This section describes each watcher in detail, but will not repeat |
1637 | information given in the last section. Any initialisation/set macros, |
1651 | information given in the last section. Any initialisation/set macros, |
1638 | functions and members specific to the watcher type are explained. |
1652 | functions and members specific to the watcher type are explained. |
1639 | |
1653 | |
1640 | Members are additionally marked with either I<[read-only]>, meaning that, |
1654 | Most members are additionally marked with either I<[read-only]>, meaning |
1641 | while the watcher is active, you can look at the member and expect some |
1655 | that, while the watcher is active, you can look at the member and expect |
1642 | sensible content, but you must not modify it (you can modify it while the |
1656 | some sensible content, but you must not modify it (you can modify it while |
1643 | watcher is stopped to your hearts content), or I<[read-write]>, which |
1657 | the watcher is stopped to your hearts content), or I<[read-write]>, which |
1644 | means you can expect it to have some sensible content while the watcher |
1658 | means you can expect it to have some sensible content while the watcher |
1645 | is active, but you can also modify it. Modifying it may not do something |
1659 | is active, but you can also modify it. Modifying it may not do something |
1646 | sensible or take immediate effect (or do anything at all), but libev will |
1660 | sensible or take immediate effect (or do anything at all), but libev will |
1647 | not crash or malfunction in any way. |
1661 | not crash or malfunction in any way. |
1648 | |
1662 | |
|
|
1663 | In any case, the documentation for each member will explain what the |
|
|
1664 | effects are, and if there are any additional access restrictions. |
1649 | |
1665 | |
1650 | =head2 C<ev_io> - is this file descriptor readable or writable? |
1666 | =head2 C<ev_io> - is this file descriptor readable or writable? |
1651 | |
1667 | |
1652 | I/O watchers check whether a file descriptor is readable or writable |
1668 | I/O watchers check whether a file descriptor is readable or writable |
1653 | in each iteration of the event loop, or, more precisely, when reading |
1669 | in each iteration of the event loop, or, more precisely, when reading |
… | |
… | |
1745 | when you rarely read from a file instead of from a socket, and want to |
1761 | when you rarely read from a file instead of from a socket, and want to |
1746 | reuse the same code path. |
1762 | reuse the same code path. |
1747 | |
1763 | |
1748 | =head3 The special problem of fork |
1764 | =head3 The special problem of fork |
1749 | |
1765 | |
1750 | Some backends (epoll, kqueue, probably linuxaio) do not support C<fork ()> |
1766 | Some backends (epoll, kqueue, linuxaio, iouring) do not support C<fork ()> |
1751 | at all or exhibit useless behaviour. Libev fully supports fork, but needs |
1767 | at all or exhibit useless behaviour. Libev fully supports fork, but needs |
1752 | to be told about it in the child if you want to continue to use it in the |
1768 | to be told about it in the child if you want to continue to use it in the |
1753 | child. |
1769 | child. |
1754 | |
1770 | |
1755 | To support fork in your child processes, you have to call C<ev_loop_fork |
1771 | To support fork in your child processes, you have to call C<ev_loop_fork |
… | |
… | |
1816 | |
1832 | |
1817 | Configures an C<ev_io> watcher. The C<fd> is the file descriptor to |
1833 | Configures an C<ev_io> watcher. The C<fd> is the file descriptor to |
1818 | receive events for and C<events> is either C<EV_READ>, C<EV_WRITE> or |
1834 | receive events for and C<events> is either C<EV_READ>, C<EV_WRITE> or |
1819 | C<EV_READ | EV_WRITE>, to express the desire to receive the given events. |
1835 | C<EV_READ | EV_WRITE>, to express the desire to receive the given events. |
1820 | |
1836 | |
1821 | =item int fd [read-only] |
1837 | =item ev_io_modify (ev_io *, int events) |
1822 | |
1838 | |
1823 | The file descriptor being watched. |
1839 | Similar to C<ev_io_set>, but only changes the event mask. Using this might |
|
|
1840 | be faster with some backends, as libev can assume that the C<fd> still |
|
|
1841 | refers to the same underlying file description, something it cannot do |
|
|
1842 | when using C<ev_io_set>. |
1824 | |
1843 | |
|
|
1844 | =item int fd [no-modify] |
|
|
1845 | |
|
|
1846 | The file descriptor being watched. While it can be read at any time, you |
|
|
1847 | must not modify this member even when the watcher is stopped - always use |
|
|
1848 | C<ev_io_set> for that. |
|
|
1849 | |
1825 | =item int events [read-only] |
1850 | =item int events [no-modify] |
1826 | |
1851 | |
1827 | The events being watched. |
1852 | The set of events the fd is being watched for, among other flags. Remember |
|
|
1853 | that this is a bit set - to test for C<EV_READ>, use C<< w->events & |
|
|
1854 | EV_READ >>, and similarly for C<EV_WRITE>. |
|
|
1855 | |
|
|
1856 | As with C<fd>, you must not modify this member even when the watcher is |
|
|
1857 | stopped, always use C<ev_io_set> or C<ev_io_modify> for that. |
1828 | |
1858 | |
1829 | =back |
1859 | =back |
1830 | |
1860 | |
1831 | =head3 Examples |
1861 | =head3 Examples |
1832 | |
1862 | |
… | |
… | |
4480 | |
4510 | |
4481 | ev_select.c only when select backend is enabled |
4511 | ev_select.c only when select backend is enabled |
4482 | ev_poll.c only when poll backend is enabled |
4512 | ev_poll.c only when poll backend is enabled |
4483 | ev_epoll.c only when the epoll backend is enabled |
4513 | ev_epoll.c only when the epoll backend is enabled |
4484 | ev_linuxaio.c only when the linux aio backend is enabled |
4514 | ev_linuxaio.c only when the linux aio backend is enabled |
|
|
4515 | ev_iouring.c only when the linux io_uring backend is enabled |
4485 | ev_kqueue.c only when the kqueue backend is enabled |
4516 | ev_kqueue.c only when the kqueue backend is enabled |
4486 | ev_port.c only when the solaris port backend is enabled |
4517 | ev_port.c only when the solaris port backend is enabled |
4487 | |
4518 | |
4488 | F<ev.c> includes the backend files directly when enabled, so you only need |
4519 | F<ev.c> includes the backend files directly when enabled, so you only need |
4489 | to compile this single file. |
4520 | to compile this single file. |
… | |
… | |
4610 | available and will probe for kernel support at runtime. This will improve |
4641 | available and will probe for kernel support at runtime. This will improve |
4611 | C<ev_signal> and C<ev_async> performance and reduce resource consumption. |
4642 | C<ev_signal> and C<ev_async> performance and reduce resource consumption. |
4612 | If undefined, it will be enabled if the headers indicate GNU/Linux + Glibc |
4643 | If undefined, it will be enabled if the headers indicate GNU/Linux + Glibc |
4613 | 2.7 or newer, otherwise disabled. |
4644 | 2.7 or newer, otherwise disabled. |
4614 | |
4645 | |
|
|
4646 | =item EV_USE_SIGNALFD |
|
|
4647 | |
|
|
4648 | If defined to be C<1>, then libev will assume that C<signalfd ()> is |
|
|
4649 | available and will probe for kernel support at runtime. This enables |
|
|
4650 | the use of EVFLAG_SIGNALFD for faster and simpler signal handling. If |
|
|
4651 | undefined, it will be enabled if the headers indicate GNU/Linux + Glibc |
|
|
4652 | 2.7 or newer, otherwise disabled. |
|
|
4653 | |
|
|
4654 | =item EV_USE_TIMERFD |
|
|
4655 | |
|
|
4656 | If defined to be C<1>, then libev will assume that C<timerfd ()> is |
|
|
4657 | available and will probe for kernel support at runtime. This allows |
|
|
4658 | libev to detect time jumps accurately. If undefined, it will be enabled |
|
|
4659 | if the headers indicate GNU/Linux + Glibc 2.8 or newer and define |
|
|
4660 | C<TFD_TIMER_CANCEL_ON_SET>, otherwise disabled. |
|
|
4661 | |
|
|
4662 | =item EV_USE_EVENTFD |
|
|
4663 | |
|
|
4664 | If defined to be C<1>, then libev will assume that C<eventfd ()> is |
|
|
4665 | available and will probe for kernel support at runtime. This will improve |
|
|
4666 | C<ev_signal> and C<ev_async> performance and reduce resource consumption. |
|
|
4667 | If undefined, it will be enabled if the headers indicate GNU/Linux + Glibc |
|
|
4668 | 2.7 or newer, otherwise disabled. |
|
|
4669 | |
4615 | =item EV_USE_SELECT |
4670 | =item EV_USE_SELECT |
4616 | |
4671 | |
4617 | If undefined or defined to be C<1>, libev will compile in support for the |
4672 | If undefined or defined to be C<1>, libev will compile in support for the |
4618 | C<select>(2) backend. No attempt at auto-detection will be done: if no |
4673 | C<select>(2) backend. No attempt at auto-detection will be done: if no |
4619 | other method takes over, select will be it. Otherwise the select backend |
4674 | other method takes over, select will be it. Otherwise the select backend |
… | |
… | |
4682 | backend for GNU/Linux systems. If undefined, it will be enabled if the |
4737 | backend for GNU/Linux systems. If undefined, it will be enabled if the |
4683 | headers indicate GNU/Linux + Glibc 2.4 or newer, otherwise disabled. |
4738 | headers indicate GNU/Linux + Glibc 2.4 or newer, otherwise disabled. |
4684 | |
4739 | |
4685 | =item EV_USE_LINUXAIO |
4740 | =item EV_USE_LINUXAIO |
4686 | |
4741 | |
|
|
4742 | If defined to be C<1>, libev will compile in support for the Linux aio |
|
|
4743 | backend (C<EV_USE_EPOLL> must also be enabled). If undefined, it will be |
|
|
4744 | enabled on linux, otherwise disabled. |
|
|
4745 | |
|
|
4746 | =item EV_USE_IOURING |
|
|
4747 | |
4687 | If defined to be C<1>, libev will compile in support for the Linux |
4748 | If defined to be C<1>, libev will compile in support for the Linux |
4688 | aio backend. Due to it's currenbt limitations it has to be requested |
4749 | io_uring backend (C<EV_USE_EPOLL> must also be enabled). Due to it's |
4689 | explicitly. If undefined, it will be enabled on linux, otherwise |
4750 | current limitations it has to be requested explicitly. If undefined, it |
4690 | disabled. |
4751 | will be enabled on linux, otherwise disabled. |
4691 | |
4752 | |
4692 | =item EV_USE_KQUEUE |
4753 | =item EV_USE_KQUEUE |
4693 | |
4754 | |
4694 | If defined to be C<1>, libev will compile in support for the BSD style |
4755 | If defined to be C<1>, libev will compile in support for the BSD style |
4695 | C<kqueue>(2) backend. Its actual availability will be detected at runtime, |
4756 | C<kqueue>(2) backend. Its actual availability will be detected at runtime, |
… | |
… | |
4973 | called. If set to C<2>, then the internal verification code will be |
5034 | called. If set to C<2>, then the internal verification code will be |
4974 | called once per loop, which can slow down libev. If set to C<3>, then the |
5035 | called once per loop, which can slow down libev. If set to C<3>, then the |
4975 | verification code will be called very frequently, which will slow down |
5036 | verification code will be called very frequently, which will slow down |
4976 | libev considerably. |
5037 | libev considerably. |
4977 | |
5038 | |
|
|
5039 | Verification errors are reported via C's C<assert> mechanism, so if you |
|
|
5040 | disable that (e.g. by defining C<NDEBUG>) then no errors will be reported. |
|
|
5041 | |
4978 | The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it |
5042 | The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it |
4979 | will be C<0>. |
5043 | will be C<0>. |
4980 | |
5044 | |
4981 | =item EV_COMMON |
5045 | =item EV_COMMON |
4982 | |
5046 | |