1 | .\" Automatically generated by Pod::Man 4.11 (Pod::Simple 3.35) |
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4 | .\" ======================================================================== |
4 | .\" ======================================================================== |
5 | .de Sp \" Vertical space (when we can't use .PP) |
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132 | .rm #[ #] #H #V #F C |
132 | .rm #[ #] #H #V #F C |
133 | .\" ======================================================================== |
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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 "2023-05-15" "libev-4.33" "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 |
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|
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 |
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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. |
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|
611 | .ie n .IP """EVFLAG_NOTIMERFD""" 4 |
|
|
612 | .el .IP "\f(CWEVFLAG_NOTIMERFD\fR" 4 |
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|
613 | .IX Item "EVFLAG_NOTIMERFD" |
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|
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 |
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|
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, |
… | |
… | |
788 | and is not embeddable, which would limit the usefulness of this backend |
801 | and is not embeddable, which would limit the usefulness of this backend |
789 | immensely. |
802 | immensely. |
790 | .ie n .IP """EVBACKEND_PORT"" (value 32, Solaris 10)" 4 |
803 | .ie n .IP """EVBACKEND_PORT"" (value 32, Solaris 10)" 4 |
791 | .el .IP "\f(CWEVBACKEND_PORT\fR (value 32, Solaris 10)" 4 |
804 | .el .IP "\f(CWEVBACKEND_PORT\fR (value 32, Solaris 10)" 4 |
792 | .IX Item "EVBACKEND_PORT (value 32, Solaris 10)" |
805 | .IX Item "EVBACKEND_PORT (value 32, Solaris 10)" |
793 | This uses the Solaris 10 event port mechanism. As with everything on Solaris, |
806 | This uses the Solaris 10 event port mechanism. As with everything on |
794 | it's really slow, but it still scales very well (O(active_fds)). |
807 | Solaris, it's really slow, but it still scales very well (O(active_fds)). |
795 | .Sp |
808 | .Sp |
796 | While this backend scales well, it requires one system call per active |
809 | While this backend scales well, it requires one system call per active |
797 | file descriptor per loop iteration. For small and medium numbers of file |
810 | file descriptor per loop iteration. For small and medium numbers of file |
798 | descriptors a \*(L"slow\*(R" \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR or \f(CW\*(C`EVBACKEND_POLL\*(C'\fR backend |
811 | descriptors a \*(L"slow\*(R" \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR or \f(CW\*(C`EVBACKEND_POLL\*(C'\fR backend |
799 | might perform better. |
812 | might perform better. |
… | |
… | |
1074 | \& \- Queue all expired timers. |
1087 | \& \- Queue all expired timers. |
1075 | \& \- Queue all expired periodics. |
1088 | \& \- Queue all expired periodics. |
1076 | \& \- Queue all idle watchers with priority higher than that of pending events. |
1089 | \& \- Queue all idle watchers with priority higher than that of pending events. |
1077 | \& \- Queue all check watchers. |
1090 | \& \- Queue all check watchers. |
1078 | \& \- Call all queued watchers in reverse order (i.e. check watchers first). |
1091 | \& \- Call all queued watchers in reverse order (i.e. check watchers first). |
1079 | \& Signals and child watchers are implemented as I/O watchers, and will |
1092 | \& Signals, async and child watchers are implemented as I/O watchers, and |
1080 | \& be handled here by queueing them when their watcher gets executed. |
1093 | \& will be handled here by queueing them when their watcher gets executed. |
1081 | \& \- If ev_break has been called, or EVRUN_ONCE or EVRUN_NOWAIT |
1094 | \& \- If ev_break has been called, or EVRUN_ONCE or EVRUN_NOWAIT |
1082 | \& were used, or there are no active watchers, goto FINISH, otherwise |
1095 | \& were used, or there are no active watchers, goto FINISH, otherwise |
1083 | \& continue with step LOOP. |
1096 | \& continue with step LOOP. |
1084 | \& FINISH: |
1097 | \& FINISH: |
1085 | \& \- Reset the ev_break status iff it was EVBREAK_ONE. |
1098 | \& \- Reset the ev_break status iff it was EVBREAK_ONE. |
… | |
… | |
1336 | 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 |
1337 | *)\*(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 |
1338 | 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. |
1339 | .PP |
1352 | .PP |
1340 | 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 |
1341 | 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 |
1342 | 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 |
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|
1356 | \&\f(CW\*(C`ev_TYPE_set\*(C'\fR macro. |
1343 | .PP |
1357 | .PP |
1344 | 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 |
1345 | 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 |
1346 | third argument. |
1360 | third argument. |
1347 | .PP |
1361 | .PP |
… | |
… | |
1518 | therefore a good idea to always call its \f(CW\*(C`ev_TYPE_stop\*(C'\fR function. |
1532 | therefore a good idea to always call its \f(CW\*(C`ev_TYPE_stop\*(C'\fR function. |
1519 | .IP "bool ev_is_active (ev_TYPE *watcher)" 4 |
1533 | .IP "bool ev_is_active (ev_TYPE *watcher)" 4 |
1520 | .IX Item "bool ev_is_active (ev_TYPE *watcher)" |
1534 | .IX Item "bool ev_is_active (ev_TYPE *watcher)" |
1521 | Returns a true value iff the watcher is active (i.e. it has been started |
1535 | Returns a true value iff the watcher is active (i.e. it has been started |
1522 | and not yet been stopped). As long as a watcher is active you must not modify |
1536 | and not yet been stopped). As long as a watcher is active you must not modify |
1523 | it. |
1537 | it unless documented otherwise. |
|
|
1538 | .Sp |
|
|
1539 | Obviously, it is safe to call this on an active watcher, or actually any |
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1540 | watcher that is initialised. |
1524 | .IP "bool ev_is_pending (ev_TYPE *watcher)" 4 |
1541 | .IP "bool ev_is_pending (ev_TYPE *watcher)" 4 |
1525 | .IX Item "bool ev_is_pending (ev_TYPE *watcher)" |
1542 | .IX Item "bool ev_is_pending (ev_TYPE *watcher)" |
1526 | Returns a true value iff the watcher is pending, (i.e. it has outstanding |
1543 | Returns a true value iff the watcher is pending, (i.e. it has outstanding |
1527 | events but its callback has not yet been invoked). As long as a watcher |
1544 | events but its callback has not yet been invoked). As long as a watcher |
1528 | is pending (but not active) you must not call an init function on it (but |
1545 | is pending (but not active) you must not call an init function on it (but |
1529 | \&\f(CW\*(C`ev_TYPE_set\*(C'\fR is safe), you must not change its priority, and you must |
1546 | \&\f(CW\*(C`ev_TYPE_set\*(C'\fR is safe), you must not change its priority, and you must |
1530 | make sure the watcher is available to libev (e.g. you cannot \f(CW\*(C`free ()\*(C'\fR |
1547 | make sure the watcher is available to libev (e.g. you cannot \f(CW\*(C`free ()\*(C'\fR |
1531 | it). |
1548 | it). |
|
|
1549 | .Sp |
|
|
1550 | It is safe to call this on any watcher in any state as long as it is |
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1551 | initialised. |
1532 | .IP "callback ev_cb (ev_TYPE *watcher)" 4 |
1552 | .IP "callback ev_cb (ev_TYPE *watcher)" 4 |
1533 | .IX Item "callback ev_cb (ev_TYPE *watcher)" |
1553 | .IX Item "callback ev_cb (ev_TYPE *watcher)" |
1534 | Returns the callback currently set on the watcher. |
1554 | Returns the callback currently set on the watcher. |
1535 | .IP "ev_set_cb (ev_TYPE *watcher, callback)" 4 |
1555 | .IP "ev_set_cb (ev_TYPE *watcher, callback)" 4 |
1536 | .IX Item "ev_set_cb (ev_TYPE *watcher, callback)" |
1556 | .IX Item "ev_set_cb (ev_TYPE *watcher, callback)" |
… | |
… | |
1549 | from being executed (except for \f(CW\*(C`ev_idle\*(C'\fR watchers). |
1569 | from being executed (except for \f(CW\*(C`ev_idle\*(C'\fR watchers). |
1550 | .Sp |
1570 | .Sp |
1551 | If you need to suppress invocation when higher priority events are pending |
1571 | If you need to suppress invocation when higher priority events are pending |
1552 | you need to look at \f(CW\*(C`ev_idle\*(C'\fR watchers, which provide this functionality. |
1572 | you need to look at \f(CW\*(C`ev_idle\*(C'\fR watchers, which provide this functionality. |
1553 | .Sp |
1573 | .Sp |
1554 | You \fImust not\fR change the priority of a watcher as long as it is active or |
1574 | You \fImust not\fR change the priority of a watcher as long as it is active |
1555 | pending. |
1575 | or pending. Reading the priority with \f(CW\*(C`ev_priority\*(C'\fR is fine in any state. |
1556 | .Sp |
1576 | .Sp |
1557 | Setting a priority outside the range of \f(CW\*(C`EV_MINPRI\*(C'\fR to \f(CW\*(C`EV_MAXPRI\*(C'\fR is |
1577 | Setting a priority outside the range of \f(CW\*(C`EV_MINPRI\*(C'\fR to \f(CW\*(C`EV_MAXPRI\*(C'\fR is |
1558 | fine, as long as you do not mind that the priority value you query might |
1578 | fine, as long as you do not mind that the priority value you query might |
1559 | or might not have been clamped to the valid range. |
1579 | or might not have been clamped to the valid range. |
1560 | .Sp |
1580 | .Sp |
… | |
… | |
1579 | callback to be invoked, which can be accomplished with this function. |
1599 | callback to be invoked, which can be accomplished with this function. |
1580 | .IP "ev_feed_event (loop, ev_TYPE *watcher, int revents)" 4 |
1600 | .IP "ev_feed_event (loop, ev_TYPE *watcher, int revents)" 4 |
1581 | .IX Item "ev_feed_event (loop, ev_TYPE *watcher, int revents)" |
1601 | .IX Item "ev_feed_event (loop, ev_TYPE *watcher, int revents)" |
1582 | Feeds the given event set into the event loop, as if the specified event |
1602 | Feeds the given event set into the event loop, as if the specified event |
1583 | had happened for the specified watcher (which must be a pointer to an |
1603 | had happened for the specified watcher (which must be a pointer to an |
1584 | initialised but not necessarily started event watcher). Obviously you must |
1604 | initialised but not necessarily started event watcher, though it can be |
1585 | not free the watcher as long as it has pending events. |
1605 | active). Obviously you must not free the watcher as long as it has pending |
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|
1606 | events. |
1586 | .Sp |
1607 | .Sp |
1587 | Stopping the watcher, letting libev invoke it, or calling |
1608 | Stopping the watcher, letting libev invoke it, or calling |
1588 | \&\f(CW\*(C`ev_clear_pending\*(C'\fR will clear the pending event, even if the watcher was |
1609 | \&\f(CW\*(C`ev_clear_pending\*(C'\fR will clear the pending event, even if the watcher was |
1589 | not started in the first place. |
1610 | not started in the first place. |
1590 | .Sp |
1611 | .Sp |
… | |
… | |
1611 | \&\f(CW\*(C`ev_TYPE_init\*(C'\fR again. |
1632 | \&\f(CW\*(C`ev_TYPE_init\*(C'\fR again. |
1612 | .IP "started/running/active" 4 |
1633 | .IP "started/running/active" 4 |
1613 | .IX Item "started/running/active" |
1634 | .IX Item "started/running/active" |
1614 | Once a watcher has been started with a call to \f(CW\*(C`ev_TYPE_start\*(C'\fR it becomes |
1635 | Once a watcher has been started with a call to \f(CW\*(C`ev_TYPE_start\*(C'\fR it becomes |
1615 | property of the event loop, and is actively waiting for events. While in |
1636 | property of the event loop, and is actively waiting for events. While in |
1616 | this state it cannot be accessed (except in a few documented ways), moved, |
1637 | this state it cannot be accessed (except in a few documented ways, such as |
1617 | freed or anything else \- the only legal thing is to keep a pointer to it, |
1638 | stoping it), moved, freed or anything else \- the only legal thing is to |
1618 | and call libev functions on it that are documented to work on active watchers. |
1639 | keep a pointer to it, and call libev functions on it that are documented |
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1640 | to work on active watchers. |
|
|
1641 | .Sp |
|
|
1642 | As a rule of thumb, before accessing a member or calling any function on |
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1643 | a watcher, it should be stopped (or freshly initialised). If that is not |
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1644 | convenient, you can check the documentation for that function or member to |
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1645 | see if it is safe to use on an active watcher. |
1619 | .IP "pending" 4 |
1646 | .IP "pending" 4 |
1620 | .IX Item "pending" |
1647 | .IX Item "pending" |
1621 | If a watcher is active and libev determines that an event it is interested |
1648 | If a watcher is active and libev determines that an event it is interested |
1622 | in has occurred (such as a timer expiring), it will become pending. It will |
1649 | in has occurred (such as a timer expiring), it will become pending. It |
1623 | stay in this pending state until either it is stopped or its callback is |
1650 | will stay in this pending state until either it is explicitly stopped or |
1624 | about to be invoked, so it is not normally pending inside the watcher |
1651 | its callback is about to be invoked, so it is not normally pending inside |
1625 | callback. |
1652 | the watcher callback. |
1626 | .Sp |
1653 | .Sp |
1627 | The watcher might or might not be active while it is pending (for example, |
1654 | Generally, the watcher might or might not be active while it is pending |
1628 | an expired non-repeating timer can be pending but no longer active). If it |
1655 | (for example, an expired non-repeating timer can be pending but no longer |
1629 | is stopped, it can be freely accessed (e.g. by calling \f(CW\*(C`ev_TYPE_set\*(C'\fR), |
1656 | active). If it is pending but not active, it can be freely accessed (e.g. |
1630 | but it is still property of the event loop at this time, so cannot be |
1657 | by calling \f(CW\*(C`ev_TYPE_set\*(C'\fR), but it is still property of the event loop at |
1631 | moved, freed or reused. And if it is active the rules described in the |
1658 | this time, so cannot be moved, freed or reused. And if it is active the |
1632 | previous item still apply. |
1659 | rules described in the previous item still apply. |
|
|
1660 | .Sp |
|
|
1661 | Explicitly stopping a watcher will also clear the pending state |
|
|
1662 | unconditionally, so it is safe to stop a watcher and then free it. |
1633 | .Sp |
1663 | .Sp |
1634 | It is also possible to feed an event on a watcher that is not active (e.g. |
1664 | It is also possible to feed an event on a watcher that is not active (e.g. |
1635 | via \f(CW\*(C`ev_feed_event\*(C'\fR), in which case it becomes pending without being |
1665 | via \f(CW\*(C`ev_feed_event\*(C'\fR), in which case it becomes pending without being |
1636 | active. |
1666 | active. |
1637 | .IP "stopped" 4 |
1667 | .IP "stopped" 4 |
… | |
… | |
1650 | .IX Subsection "WATCHER PRIORITY MODELS" |
1680 | .IX Subsection "WATCHER PRIORITY MODELS" |
1651 | Many event loops support \fIwatcher priorities\fR, which are usually small |
1681 | Many event loops support \fIwatcher priorities\fR, which are usually small |
1652 | integers that influence the ordering of event callback invocation |
1682 | integers that influence the ordering of event callback invocation |
1653 | between watchers in some way, all else being equal. |
1683 | between watchers in some way, all else being equal. |
1654 | .PP |
1684 | .PP |
1655 | In libev, Watcher priorities can be set using \f(CW\*(C`ev_set_priority\*(C'\fR. See its |
1685 | 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 |
1686 | description for the more technical details such as the actual priority |
1657 | range. |
1687 | range. |
1658 | .PP |
1688 | .PP |
1659 | There are two common ways how these these priorities are being interpreted |
1689 | There are two common ways how these these priorities are being interpreted |
1660 | by event loops: |
1690 | by event loops: |
… | |
… | |
1754 | .IX Header "WATCHER TYPES" |
1784 | .IX Header "WATCHER TYPES" |
1755 | This section describes each watcher in detail, but will not repeat |
1785 | This section describes each watcher in detail, but will not repeat |
1756 | information given in the last section. Any initialisation/set macros, |
1786 | information given in the last section. Any initialisation/set macros, |
1757 | functions and members specific to the watcher type are explained. |
1787 | functions and members specific to the watcher type are explained. |
1758 | .PP |
1788 | .PP |
1759 | Members are additionally marked with either \fI[read\-only]\fR, meaning that, |
1789 | Most members are additionally marked with either \fI[read\-only]\fR, meaning |
1760 | while the watcher is active, you can look at the member and expect some |
1790 | that, while the watcher is active, you can look at the member and expect |
1761 | sensible content, but you must not modify it (you can modify it while the |
1791 | some sensible content, but you must not modify it (you can modify it while |
1762 | watcher is stopped to your hearts content), or \fI[read\-write]\fR, which |
1792 | the watcher is stopped to your hearts content), or \fI[read\-write]\fR, which |
1763 | means you can expect it to have some sensible content while the watcher |
1793 | means you can expect it to have some sensible content while the watcher is |
1764 | is active, but you can also modify it. Modifying it may not do something |
1794 | active, but you can also modify it (within the same thread as the event |
|
|
1795 | loop, i.e. without creating data races). Modifying it may not do something |
1765 | sensible or take immediate effect (or do anything at all), but libev will |
1796 | sensible or take immediate effect (or do anything at all), but libev will |
1766 | not crash or malfunction in any way. |
1797 | not crash or malfunction in any way. |
|
|
1798 | .PP |
|
|
1799 | In any case, the documentation for each member will explain what the |
|
|
1800 | effects are, and if there are any additional access restrictions. |
1767 | .ie n .SS """ev_io"" \- is this file descriptor readable or writable?" |
1801 | .ie n .SS """ev_io"" \- is this file descriptor readable or writable?" |
1768 | .el .SS "\f(CWev_io\fP \- is this file descriptor readable or writable?" |
1802 | .el .SS "\f(CWev_io\fP \- is this file descriptor readable or writable?" |
1769 | .IX Subsection "ev_io - is this file descriptor readable or writable?" |
1803 | .IX Subsection "ev_io - is this file descriptor readable or writable?" |
1770 | I/O watchers check whether a file descriptor is readable or writable |
1804 | I/O watchers check whether a file descriptor is readable or writable |
1771 | in each iteration of the event loop, or, more precisely, when reading |
1805 | in each iteration of the event loop, or, more precisely, when reading |
… | |
… | |
1867 | reuse the same code path. |
1901 | reuse the same code path. |
1868 | .PP |
1902 | .PP |
1869 | \fIThe special problem of fork\fR |
1903 | \fIThe special problem of fork\fR |
1870 | .IX Subsection "The special problem of fork" |
1904 | .IX Subsection "The special problem of fork" |
1871 | .PP |
1905 | .PP |
1872 | Some backends (epoll, kqueue, probably linuxaio) do not support \f(CW\*(C`fork ()\*(C'\fR |
1906 | 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 |
1907 | 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 |
1908 | to be told about it in the child if you want to continue to use it in the |
1875 | child. |
1909 | child. |
1876 | .PP |
1910 | .PP |
1877 | To support fork in your child processes, you have to call \f(CW\*(C`ev_loop_fork |
1911 | To support fork in your child processes, you have to call \f(CW\*(C`ev_loop_fork |
… | |
… | |
1937 | .PD 0 |
1971 | .PD 0 |
1938 | .IP "ev_io_set (ev_io *, int fd, int events)" 4 |
1972 | .IP "ev_io_set (ev_io *, int fd, int events)" 4 |
1939 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
1973 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
1940 | .PD |
1974 | .PD |
1941 | Configures an \f(CW\*(C`ev_io\*(C'\fR watcher. The \f(CW\*(C`fd\*(C'\fR is the file descriptor to |
1975 | Configures an \f(CW\*(C`ev_io\*(C'\fR watcher. The \f(CW\*(C`fd\*(C'\fR is the file descriptor to |
1942 | 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 |
1976 | 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 |
1943 | \&\f(CW\*(C`EV_READ | EV_WRITE\*(C'\fR, to express the desire to receive the given events. |
1977 | \&\f(CW\*(C`EV_READ | EV_WRITE\*(C'\fR or \f(CW0\fR, to express the desire to receive the given |
|
|
1978 | events. |
|
|
1979 | .Sp |
|
|
1980 | Note that setting the \f(CW\*(C`events\*(C'\fR to \f(CW0\fR and starting the watcher is |
|
|
1981 | supported, but not specially optimized \- if your program sometimes happens |
|
|
1982 | to generate this combination this is fine, but if it is easy to avoid |
|
|
1983 | starting an io watcher watching for no events you should do so. |
|
|
1984 | .IP "ev_io_modify (ev_io *, int events)" 4 |
|
|
1985 | .IX Item "ev_io_modify (ev_io *, int events)" |
|
|
1986 | Similar to \f(CW\*(C`ev_io_set\*(C'\fR, but only changes the requested events. Using this |
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|
1987 | might be faster with some backends, as libev can assume that the \f(CW\*(C`fd\*(C'\fR |
|
|
1988 | still refers to the same underlying file description, something it cannot |
|
|
1989 | do when using \f(CW\*(C`ev_io_set\*(C'\fR. |
1944 | .IP "int fd [read\-only]" 4 |
1990 | .IP "int fd [no\-modify]" 4 |
1945 | .IX Item "int fd [read-only]" |
1991 | .IX Item "int fd [no-modify]" |
1946 | The file descriptor being watched. |
1992 | The file descriptor being watched. While it can be read at any time, you |
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|
1993 | must not modify this member even when the watcher is stopped \- always use |
|
|
1994 | \&\f(CW\*(C`ev_io_set\*(C'\fR for that. |
1947 | .IP "int events [read\-only]" 4 |
1995 | .IP "int events [no\-modify]" 4 |
1948 | .IX Item "int events [read-only]" |
1996 | .IX Item "int events [no-modify]" |
1949 | The events being watched. |
1997 | The set of events the fd is being watched for, among other flags. Remember |
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|
1998 | that this is a bit set \- to test for \f(CW\*(C`EV_READ\*(C'\fR, use \f(CW\*(C`w\->events & |
|
|
1999 | EV_READ\*(C'\fR, and similarly for \f(CW\*(C`EV_WRITE\*(C'\fR. |
|
|
2000 | .Sp |
|
|
2001 | As with \f(CW\*(C`fd\*(C'\fR, you must not modify this member even when the watcher is |
|
|
2002 | stopped, always use \f(CW\*(C`ev_io_set\*(C'\fR or \f(CW\*(C`ev_io_modify\*(C'\fR for that. |
1950 | .PP |
2003 | .PP |
1951 | \fIExamples\fR |
2004 | \fIExamples\fR |
1952 | .IX Subsection "Examples" |
2005 | .IX Subsection "Examples" |
1953 | .PP |
2006 | .PP |
1954 | Example: Call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well |
2007 | Example: Call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well |
… | |
… | |
3965 | .PP |
4018 | .PP |
3966 | First, you need to associate some data with the event loop: |
4019 | First, you need to associate some data with the event loop: |
3967 | .PP |
4020 | .PP |
3968 | .Vb 6 |
4021 | .Vb 6 |
3969 | \& typedef struct { |
4022 | \& typedef struct { |
3970 | \& mutex_t lock; /* global loop lock */ |
4023 | \& pthread_mutex_t lock; /* global loop lock */ |
|
|
4024 | \& pthread_t tid; |
|
|
4025 | \& pthread_cond_t invoke_cv; |
3971 | \& ev_async async_w; |
4026 | \& ev_async async_w; |
3972 | \& thread_t tid; |
|
|
3973 | \& cond_t invoke_cv; |
|
|
3974 | \& } userdata; |
4027 | \& } userdata; |
3975 | \& |
4028 | \& |
3976 | \& void prepare_loop (EV_P) |
4029 | \& void prepare_loop (EV_P) |
3977 | \& { |
4030 | \& { |
3978 | \& // for simplicity, we use a static userdata struct. |
4031 | \& // for simplicity, we use a static userdata struct. |
3979 | \& static userdata u; |
4032 | \& static userdata u; |
3980 | \& |
4033 | \& |
3981 | \& ev_async_init (&u\->async_w, async_cb); |
4034 | \& ev_async_init (&u.async_w, async_cb); |
3982 | \& ev_async_start (EV_A_ &u\->async_w); |
4035 | \& ev_async_start (EV_A_ &u.async_w); |
3983 | \& |
4036 | \& |
3984 | \& pthread_mutex_init (&u\->lock, 0); |
4037 | \& pthread_mutex_init (&u.lock, 0); |
3985 | \& pthread_cond_init (&u\->invoke_cv, 0); |
4038 | \& pthread_cond_init (&u.invoke_cv, 0); |
3986 | \& |
4039 | \& |
3987 | \& // now associate this with the loop |
4040 | \& // now associate this with the loop |
3988 | \& ev_set_userdata (EV_A_ u); |
4041 | \& ev_set_userdata (EV_A_ &u); |
3989 | \& ev_set_invoke_pending_cb (EV_A_ l_invoke); |
4042 | \& ev_set_invoke_pending_cb (EV_A_ l_invoke); |
3990 | \& ev_set_loop_release_cb (EV_A_ l_release, l_acquire); |
4043 | \& ev_set_loop_release_cb (EV_A_ l_release, l_acquire); |
3991 | \& |
4044 | \& |
3992 | \& // then create the thread running ev_run |
4045 | \& // then create the thread running ev_run |
3993 | \& pthread_create (&u\->tid, 0, l_run, EV_A); |
4046 | \& pthread_create (&u.tid, 0, l_run, EV_A); |
3994 | \& } |
4047 | \& } |
3995 | .Ve |
4048 | .Ve |
3996 | .PP |
4049 | .PP |
3997 | The callback for the \f(CW\*(C`ev_async\*(C'\fR watcher does nothing: the watcher is used |
4050 | The callback for the \f(CW\*(C`ev_async\*(C'\fR watcher does nothing: the watcher is used |
3998 | solely to wake up the event loop so it takes notice of any new watchers |
4051 | solely to wake up the event loop so it takes notice of any new watchers |
… | |
… | |
4382 | gets automatically stopped and restarted when reconfiguring it with this |
4435 | gets automatically stopped and restarted when reconfiguring it with this |
4383 | method. |
4436 | method. |
4384 | .Sp |
4437 | .Sp |
4385 | For \f(CW\*(C`ev::embed\*(C'\fR watchers this method is called \f(CW\*(C`set_embed\*(C'\fR, to avoid |
4438 | For \f(CW\*(C`ev::embed\*(C'\fR watchers this method is called \f(CW\*(C`set_embed\*(C'\fR, to avoid |
4386 | clashing with the \f(CW\*(C`set (loop)\*(C'\fR method. |
4439 | clashing with the \f(CW\*(C`set (loop)\*(C'\fR method. |
|
|
4440 | .Sp |
|
|
4441 | For \f(CW\*(C`ev::io\*(C'\fR watchers there is an additional \f(CW\*(C`set\*(C'\fR method that acepts a |
|
|
4442 | new event mask only, and internally calls \f(CW\*(C`ev_io_modify\*(C'\fR. |
4387 | .IP "w\->start ()" 4 |
4443 | .IP "w\->start ()" 4 |
4388 | .IX Item "w->start ()" |
4444 | .IX Item "w->start ()" |
4389 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument, as the |
4445 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument, as the |
4390 | constructor already stores the event loop. |
4446 | constructor already stores the event loop. |
4391 | .IP "w\->start ([arguments])" 4 |
4447 | .IP "w\->start ([arguments])" 4 |
… | |
… | |
4620 | \& |
4676 | \& |
4621 | \& ev_select.c only when select backend is enabled |
4677 | \& ev_select.c only when select backend is enabled |
4622 | \& ev_poll.c only when poll backend is enabled |
4678 | \& ev_poll.c only when poll backend is enabled |
4623 | \& ev_epoll.c only when the epoll backend is enabled |
4679 | \& ev_epoll.c only when the epoll backend is enabled |
4624 | \& ev_linuxaio.c only when the linux aio backend is enabled |
4680 | \& ev_linuxaio.c only when the linux aio backend is enabled |
|
|
4681 | \& ev_iouring.c only when the linux io_uring backend is enabled |
4625 | \& ev_kqueue.c only when the kqueue backend is enabled |
4682 | \& ev_kqueue.c only when the kqueue backend is enabled |
4626 | \& ev_port.c only when the solaris port backend is enabled |
4683 | \& ev_port.c only when the solaris port backend is enabled |
4627 | .Ve |
4684 | .Ve |
4628 | .PP |
4685 | .PP |
4629 | \&\fIev.c\fR includes the backend files directly when enabled, so you only need |
4686 | \&\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). |
4799 | higher, as it simplifies linking (no need for \f(CW\*(C`\-lrt\*(C'\fR). |
4743 | .IP "\s-1EV_USE_NANOSLEEP\s0" 4 |
4800 | .IP "\s-1EV_USE_NANOSLEEP\s0" 4 |
4744 | .IX Item "EV_USE_NANOSLEEP" |
4801 | .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 |
4802 | 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. |
4803 | and will use it for delays. Otherwise it will use \f(CW\*(C`select ()\*(C'\fR. |
|
|
4804 | .IP "\s-1EV_USE_EVENTFD\s0" 4 |
|
|
4805 | .IX Item "EV_USE_EVENTFD" |
|
|
4806 | If defined to be \f(CW1\fR, then libev will assume that \f(CW\*(C`eventfd ()\*(C'\fR is |
|
|
4807 | available and will probe for kernel support at runtime. This will improve |
|
|
4808 | \&\f(CW\*(C`ev_signal\*(C'\fR and \f(CW\*(C`ev_async\*(C'\fR performance and reduce resource consumption. |
|
|
4809 | If undefined, it will be enabled if the headers indicate GNU/Linux + Glibc |
|
|
4810 | 2.7 or newer, otherwise disabled. |
|
|
4811 | .IP "\s-1EV_USE_SIGNALFD\s0" 4 |
|
|
4812 | .IX Item "EV_USE_SIGNALFD" |
|
|
4813 | If defined to be \f(CW1\fR, then libev will assume that \f(CW\*(C`signalfd ()\*(C'\fR is |
|
|
4814 | available and will probe for kernel support at runtime. This enables |
|
|
4815 | the use of \s-1EVFLAG_SIGNALFD\s0 for faster and simpler signal handling. If |
|
|
4816 | undefined, it will be enabled if the headers indicate GNU/Linux + Glibc |
|
|
4817 | 2.7 or newer, otherwise disabled. |
|
|
4818 | .IP "\s-1EV_USE_TIMERFD\s0" 4 |
|
|
4819 | .IX Item "EV_USE_TIMERFD" |
|
|
4820 | If defined to be \f(CW1\fR, then libev will assume that \f(CW\*(C`timerfd ()\*(C'\fR is |
|
|
4821 | available and will probe for kernel support at runtime. This allows |
|
|
4822 | libev to detect time jumps accurately. If undefined, it will be enabled |
|
|
4823 | if the headers indicate GNU/Linux + Glibc 2.8 or newer and define |
|
|
4824 | \&\f(CW\*(C`TFD_TIMER_CANCEL_ON_SET\*(C'\fR, otherwise disabled. |
4747 | .IP "\s-1EV_USE_EVENTFD\s0" 4 |
4825 | .IP "\s-1EV_USE_EVENTFD\s0" 4 |
4748 | .IX Item "EV_USE_EVENTFD" |
4826 | .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 |
4827 | 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 |
4828 | 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. |
4829 | \&\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 |
4890 | 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 |
4891 | 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. |
4892 | headers indicate GNU/Linux + Glibc 2.4 or newer, otherwise disabled. |
4815 | .IP "\s-1EV_USE_LINUXAIO\s0" 4 |
4893 | .IP "\s-1EV_USE_LINUXAIO\s0" 4 |
4816 | .IX Item "EV_USE_LINUXAIO" |
4894 | .IX Item "EV_USE_LINUXAIO" |
|
|
4895 | If defined to be \f(CW1\fR, libev will compile in support for the Linux aio |
|
|
4896 | backend (\f(CW\*(C`EV_USE_EPOLL\*(C'\fR must also be enabled). If undefined, it will be |
|
|
4897 | enabled on linux, otherwise disabled. |
|
|
4898 | .IP "\s-1EV_USE_IOURING\s0" 4 |
|
|
4899 | .IX Item "EV_USE_IOURING" |
4817 | If defined to be \f(CW1\fR, libev will compile in support for the Linux |
4900 | 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 |
4901 | 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 |
4902 | current limitations it has to be requested explicitly. If undefined, it |
4820 | disabled. |
4903 | will be enabled on linux, otherwise disabled. |
4821 | .IP "\s-1EV_USE_KQUEUE\s0" 4 |
4904 | .IP "\s-1EV_USE_KQUEUE\s0" 4 |
4822 | .IX Item "EV_USE_KQUEUE" |
4905 | .IX Item "EV_USE_KQUEUE" |
4823 | If defined to be \f(CW1\fR, libev will compile in support for the \s-1BSD\s0 style |
4906 | 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, |
4907 | \&\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 |
4908 | 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 |
5164 | 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 |
5165 | 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 |
5166 | 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 |
5167 | verification code will be called very frequently, which will slow down |
5085 | libev considerably. |
5168 | libev considerably. |
|
|
5169 | .Sp |
|
|
5170 | Verification errors are reported via C's \f(CW\*(C`assert\*(C'\fR mechanism, so if you |
|
|
5171 | disable that (e.g. by defining \f(CW\*(C`NDEBUG\*(C'\fR) then no errors will be reported. |
5086 | .Sp |
5172 | .Sp |
5087 | The default is \f(CW1\fR, unless \f(CW\*(C`EV_FEATURES\*(C'\fR overrides it, in which case it |
5173 | 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. |
5174 | will be \f(CW0\fR. |
5089 | .IP "\s-1EV_COMMON\s0" 4 |
5175 | .IP "\s-1EV_COMMON\s0" 4 |
5090 | .IX Item "EV_COMMON" |
5176 | .IX Item "EV_COMMON" |