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1 | .\" Automatically generated by Pod::Man 4.14 (Pod::Simple 3.43) |
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4 | .\" ======================================================================== |
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132 | .rm #[ #] #H #V #F C |
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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" |
… | |
… | |
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. |
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|
611 | .ie n .IP """EVFLAG_NOTIMERFD""" 4 |
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|
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. |
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 |
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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. |
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, |
… | |
… | |
792 | 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 |
793 | immensely. |
802 | immensely. |
794 | .ie n .IP """EVBACKEND_PORT"" (value 32, Solaris 10)" 4 |
803 | .ie n .IP """EVBACKEND_PORT"" (value 32, Solaris 10)" 4 |
795 | .el .IP "\f(CWEVBACKEND_PORT\fR (value 32, Solaris 10)" 4 |
804 | .el .IP "\f(CWEVBACKEND_PORT\fR (value 32, Solaris 10)" 4 |
796 | .IX Item "EVBACKEND_PORT (value 32, Solaris 10)" |
805 | .IX Item "EVBACKEND_PORT (value 32, Solaris 10)" |
797 | 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 |
798 | 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)). |
799 | .Sp |
808 | .Sp |
800 | 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 |
801 | 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 |
802 | 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 |
803 | might perform better. |
812 | might perform better. |
… | |
… | |
1078 | \& \- Queue all expired timers. |
1087 | \& \- Queue all expired timers. |
1079 | \& \- Queue all expired periodics. |
1088 | \& \- Queue all expired periodics. |
1080 | \& \- 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. |
1081 | \& \- Queue all check watchers. |
1090 | \& \- Queue all check watchers. |
1082 | \& \- 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). |
1083 | \& 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 |
1084 | \& be handled here by queueing them when their watcher gets executed. |
1093 | \& will be handled here by queueing them when their watcher gets executed. |
1085 | \& \- 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 |
1086 | \& were used, or there are no active watchers, goto FINISH, otherwise |
1095 | \& were used, or there are no active watchers, goto FINISH, otherwise |
1087 | \& continue with step LOOP. |
1096 | \& continue with step LOOP. |
1088 | \& FINISH: |
1097 | \& FINISH: |
1089 | \& \- Reset the ev_break status iff it was EVBREAK_ONE. |
1098 | \& \- Reset the ev_break status iff it was EVBREAK_ONE. |
… | |
… | |
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 |
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|
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 |
… | |
… | |
1522 | 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. |
1523 | .IP "bool ev_is_active (ev_TYPE *watcher)" 4 |
1533 | .IP "bool ev_is_active (ev_TYPE *watcher)" 4 |
1524 | .IX Item "bool ev_is_active (ev_TYPE *watcher)" |
1534 | .IX Item "bool ev_is_active (ev_TYPE *watcher)" |
1525 | 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 |
1526 | 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 |
1527 | it. |
1537 | it unless documented otherwise. |
|
|
1538 | .Sp |
|
|
1539 | Obviously, it is safe to call this on an active watcher, or actually any |
|
|
1540 | watcher that is initialised. |
1528 | .IP "bool ev_is_pending (ev_TYPE *watcher)" 4 |
1541 | .IP "bool ev_is_pending (ev_TYPE *watcher)" 4 |
1529 | .IX Item "bool ev_is_pending (ev_TYPE *watcher)" |
1542 | .IX Item "bool ev_is_pending (ev_TYPE *watcher)" |
1530 | 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 |
1531 | 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 |
1532 | 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 |
1533 | \&\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 |
1534 | 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 |
1535 | it). |
1548 | it). |
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|
1549 | .Sp |
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1550 | It is safe to call this on any watcher in any state as long as it is |
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1551 | initialised. |
1536 | .IP "callback ev_cb (ev_TYPE *watcher)" 4 |
1552 | .IP "callback ev_cb (ev_TYPE *watcher)" 4 |
1537 | .IX Item "callback ev_cb (ev_TYPE *watcher)" |
1553 | .IX Item "callback ev_cb (ev_TYPE *watcher)" |
1538 | Returns the callback currently set on the watcher. |
1554 | Returns the callback currently set on the watcher. |
1539 | .IP "ev_set_cb (ev_TYPE *watcher, callback)" 4 |
1555 | .IP "ev_set_cb (ev_TYPE *watcher, callback)" 4 |
1540 | .IX Item "ev_set_cb (ev_TYPE *watcher, callback)" |
1556 | .IX Item "ev_set_cb (ev_TYPE *watcher, callback)" |
… | |
… | |
1553 | 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). |
1554 | .Sp |
1570 | .Sp |
1555 | 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 |
1556 | 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. |
1557 | .Sp |
1573 | .Sp |
1558 | 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 |
1559 | pending. |
1575 | or pending. Reading the priority with \f(CW\*(C`ev_priority\*(C'\fR is fine in any state. |
1560 | .Sp |
1576 | .Sp |
1561 | 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 |
1562 | 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 |
1563 | or might not have been clamped to the valid range. |
1579 | or might not have been clamped to the valid range. |
1564 | .Sp |
1580 | .Sp |
… | |
… | |
1583 | callback to be invoked, which can be accomplished with this function. |
1599 | callback to be invoked, which can be accomplished with this function. |
1584 | .IP "ev_feed_event (loop, ev_TYPE *watcher, int revents)" 4 |
1600 | .IP "ev_feed_event (loop, ev_TYPE *watcher, int revents)" 4 |
1585 | .IX Item "ev_feed_event (loop, ev_TYPE *watcher, int revents)" |
1601 | .IX Item "ev_feed_event (loop, ev_TYPE *watcher, int revents)" |
1586 | 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 |
1587 | 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 |
1588 | initialised but not necessarily started event watcher). Obviously you must |
1604 | initialised but not necessarily started event watcher, though it can be |
1589 | 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. |
1590 | .Sp |
1607 | .Sp |
1591 | Stopping the watcher, letting libev invoke it, or calling |
1608 | Stopping the watcher, letting libev invoke it, or calling |
1592 | \&\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 |
1593 | not started in the first place. |
1610 | not started in the first place. |
1594 | .Sp |
1611 | .Sp |
… | |
… | |
1615 | \&\f(CW\*(C`ev_TYPE_init\*(C'\fR again. |
1632 | \&\f(CW\*(C`ev_TYPE_init\*(C'\fR again. |
1616 | .IP "started/running/active" 4 |
1633 | .IP "started/running/active" 4 |
1617 | .IX Item "started/running/active" |
1634 | .IX Item "started/running/active" |
1618 | 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 |
1619 | 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 |
1620 | 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 |
1621 | 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 |
1622 | 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. |
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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. |
1623 | .IP "pending" 4 |
1646 | .IP "pending" 4 |
1624 | .IX Item "pending" |
1647 | .IX Item "pending" |
1625 | 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 |
1626 | 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 |
1627 | 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 |
1628 | 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 |
1629 | callback. |
1652 | the watcher callback. |
1630 | .Sp |
1653 | .Sp |
1631 | 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 |
1632 | 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 |
1633 | 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. |
1634 | 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 |
1635 | 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 |
1636 | previous item still apply. |
1659 | rules described in the previous item still apply. |
|
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1660 | .Sp |
|
|
1661 | Explicitly stopping a watcher will also clear the pending state |
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|
1662 | unconditionally, so it is safe to stop a watcher and then free it. |
1637 | .Sp |
1663 | .Sp |
1638 | 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. |
1639 | 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 |
1640 | active. |
1666 | active. |
1641 | .IP "stopped" 4 |
1667 | .IP "stopped" 4 |
… | |
… | |
1654 | .IX Subsection "WATCHER PRIORITY MODELS" |
1680 | .IX Subsection "WATCHER PRIORITY MODELS" |
1655 | Many event loops support \fIwatcher priorities\fR, which are usually small |
1681 | Many event loops support \fIwatcher priorities\fR, which are usually small |
1656 | integers that influence the ordering of event callback invocation |
1682 | integers that influence the ordering of event callback invocation |
1657 | between watchers in some way, all else being equal. |
1683 | between watchers in some way, all else being equal. |
1658 | .PP |
1684 | .PP |
1659 | 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 |
1660 | description for the more technical details such as the actual priority |
1686 | description for the more technical details such as the actual priority |
1661 | range. |
1687 | range. |
1662 | .PP |
1688 | .PP |
1663 | 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 |
1664 | by event loops: |
1690 | by event loops: |
… | |
… | |
1758 | .IX Header "WATCHER TYPES" |
1784 | .IX Header "WATCHER TYPES" |
1759 | This section describes each watcher in detail, but will not repeat |
1785 | This section describes each watcher in detail, but will not repeat |
1760 | information given in the last section. Any initialisation/set macros, |
1786 | information given in the last section. Any initialisation/set macros, |
1761 | functions and members specific to the watcher type are explained. |
1787 | functions and members specific to the watcher type are explained. |
1762 | .PP |
1788 | .PP |
1763 | 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 |
1764 | 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 |
1765 | 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 |
1766 | 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 |
1767 | 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 |
1768 | 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 |
1769 | 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 |
1770 | 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. |
1771 | .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?" |
1772 | .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?" |
1773 | .IX Subsection "ev_io - is this file descriptor readable or writable?" |
1803 | .IX Subsection "ev_io - is this file descriptor readable or writable?" |
1774 | 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 |
1775 | 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 |
… | |
… | |
1871 | reuse the same code path. |
1901 | reuse the same code path. |
1872 | .PP |
1902 | .PP |
1873 | \fIThe special problem of fork\fR |
1903 | \fIThe special problem of fork\fR |
1874 | .IX Subsection "The special problem of fork" |
1904 | .IX Subsection "The special problem of fork" |
1875 | .PP |
1905 | .PP |
1876 | 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 |
1877 | 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 |
1878 | 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 |
1879 | child. |
1909 | child. |
1880 | .PP |
1910 | .PP |
1881 | 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 |
… | |
… | |
1941 | .PD 0 |
1971 | .PD 0 |
1942 | .IP "ev_io_set (ev_io *, int fd, int events)" 4 |
1972 | .IP "ev_io_set (ev_io *, int fd, int events)" 4 |
1943 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
1973 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
1944 | .PD |
1974 | .PD |
1945 | 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 |
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 |
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 |
1947 | \&\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 |
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1978 | events. |
|
|
1979 | .Sp |
|
|
1980 | Note that setting the \f(CW\*(C`events\*(C'\fR to \f(CW0\fR and starting the watcher is |
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1981 | supported, but not specially optimized \- if your program sometimes happens |
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1982 | to generate this combination this is fine, but if it is easy to avoid |
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1983 | starting an io watcher watching for no events you should do so. |
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1984 | .IP "ev_io_modify (ev_io *, int events)" 4 |
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1985 | .IX Item "ev_io_modify (ev_io *, int events)" |
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|
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 |
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1988 | still refers to the same underlying file description, something it cannot |
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1989 | do when using \f(CW\*(C`ev_io_set\*(C'\fR. |
1948 | .IP "int fd [read\-only]" 4 |
1990 | .IP "int fd [no\-modify]" 4 |
1949 | .IX Item "int fd [read-only]" |
1991 | .IX Item "int fd [no-modify]" |
1950 | 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 |
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1994 | \&\f(CW\*(C`ev_io_set\*(C'\fR for that. |
1951 | .IP "int events [read\-only]" 4 |
1995 | .IP "int events [no\-modify]" 4 |
1952 | .IX Item "int events [read-only]" |
1996 | .IX Item "int events [no-modify]" |
1953 | 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 & |
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1999 | EV_READ\*(C'\fR, and similarly for \f(CW\*(C`EV_WRITE\*(C'\fR. |
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2000 | .Sp |
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2001 | As with \f(CW\*(C`fd\*(C'\fR, you must not modify this member even when the watcher is |
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2002 | stopped, always use \f(CW\*(C`ev_io_set\*(C'\fR or \f(CW\*(C`ev_io_modify\*(C'\fR for that. |
1954 | .PP |
2003 | .PP |
1955 | \fIExamples\fR |
2004 | \fIExamples\fR |
1956 | .IX Subsection "Examples" |
2005 | .IX Subsection "Examples" |
1957 | .PP |
2006 | .PP |
1958 | 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 |
… | |
… | |
3969 | .PP |
4018 | .PP |
3970 | First, you need to associate some data with the event loop: |
4019 | First, you need to associate some data with the event loop: |
3971 | .PP |
4020 | .PP |
3972 | .Vb 6 |
4021 | .Vb 6 |
3973 | \& typedef struct { |
4022 | \& typedef struct { |
3974 | \& mutex_t lock; /* global loop lock */ |
4023 | \& pthread_mutex_t lock; /* global loop lock */ |
|
|
4024 | \& pthread_t tid; |
|
|
4025 | \& pthread_cond_t invoke_cv; |
3975 | \& ev_async async_w; |
4026 | \& ev_async async_w; |
3976 | \& thread_t tid; |
|
|
3977 | \& cond_t invoke_cv; |
|
|
3978 | \& } userdata; |
4027 | \& } userdata; |
3979 | \& |
4028 | \& |
3980 | \& void prepare_loop (EV_P) |
4029 | \& void prepare_loop (EV_P) |
3981 | \& { |
4030 | \& { |
3982 | \& // for simplicity, we use a static userdata struct. |
4031 | \& // for simplicity, we use a static userdata struct. |
3983 | \& static userdata u; |
4032 | \& static userdata u; |
3984 | \& |
4033 | \& |
3985 | \& ev_async_init (&u\->async_w, async_cb); |
4034 | \& ev_async_init (&u.async_w, async_cb); |
3986 | \& ev_async_start (EV_A_ &u\->async_w); |
4035 | \& ev_async_start (EV_A_ &u.async_w); |
3987 | \& |
4036 | \& |
3988 | \& pthread_mutex_init (&u\->lock, 0); |
4037 | \& pthread_mutex_init (&u.lock, 0); |
3989 | \& pthread_cond_init (&u\->invoke_cv, 0); |
4038 | \& pthread_cond_init (&u.invoke_cv, 0); |
3990 | \& |
4039 | \& |
3991 | \& // now associate this with the loop |
4040 | \& // now associate this with the loop |
3992 | \& ev_set_userdata (EV_A_ u); |
4041 | \& ev_set_userdata (EV_A_ &u); |
3993 | \& ev_set_invoke_pending_cb (EV_A_ l_invoke); |
4042 | \& ev_set_invoke_pending_cb (EV_A_ l_invoke); |
3994 | \& ev_set_loop_release_cb (EV_A_ l_release, l_acquire); |
4043 | \& ev_set_loop_release_cb (EV_A_ l_release, l_acquire); |
3995 | \& |
4044 | \& |
3996 | \& // then create the thread running ev_run |
4045 | \& // then create the thread running ev_run |
3997 | \& pthread_create (&u\->tid, 0, l_run, EV_A); |
4046 | \& pthread_create (&u.tid, 0, l_run, EV_A); |
3998 | \& } |
4047 | \& } |
3999 | .Ve |
4048 | .Ve |
4000 | .PP |
4049 | .PP |
4001 | 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 |
4002 | 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 |
… | |
… | |
4386 | gets automatically stopped and restarted when reconfiguring it with this |
4435 | gets automatically stopped and restarted when reconfiguring it with this |
4387 | method. |
4436 | method. |
4388 | .Sp |
4437 | .Sp |
4389 | 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 |
4390 | 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. |
4391 | .IP "w\->start ()" 4 |
4443 | .IP "w\->start ()" 4 |
4392 | .IX Item "w->start ()" |
4444 | .IX Item "w->start ()" |
4393 | 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 |
4394 | constructor already stores the event loop. |
4446 | constructor already stores the event loop. |
4395 | .IP "w\->start ([arguments])" 4 |
4447 | .IP "w\->start ([arguments])" 4 |
… | |
… | |
4624 | \& |
4676 | \& |
4625 | \& ev_select.c only when select backend is enabled |
4677 | \& ev_select.c only when select backend is enabled |
4626 | \& ev_poll.c only when poll backend is enabled |
4678 | \& ev_poll.c only when poll backend is enabled |
4627 | \& ev_epoll.c only when the epoll backend is enabled |
4679 | \& ev_epoll.c only when the epoll backend is enabled |
4628 | \& 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 |
4629 | \& ev_kqueue.c only when the kqueue backend is enabled |
4682 | \& ev_kqueue.c only when the kqueue backend is enabled |
4630 | \& ev_port.c only when the solaris port backend is enabled |
4683 | \& ev_port.c only when the solaris port backend is enabled |
4631 | .Ve |
4684 | .Ve |
4632 | .PP |
4685 | .PP |
4633 | \&\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 |
… | |
… | |
4746 | 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). |
4747 | .IP "\s-1EV_USE_NANOSLEEP\s0" 4 |
4800 | .IP "\s-1EV_USE_NANOSLEEP\s0" 4 |
4748 | .IX Item "EV_USE_NANOSLEEP" |
4801 | .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 |
4802 | 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. |
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. |
4751 | .IP "\s-1EV_USE_EVENTFD\s0" 4 |
4825 | .IP "\s-1EV_USE_EVENTFD\s0" 4 |
4752 | .IX Item "EV_USE_EVENTFD" |
4826 | .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 |
4827 | 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 |
4828 | 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. |
4829 | \&\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 |
4890 | 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 |
4891 | 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. |
4892 | headers indicate GNU/Linux + Glibc 2.4 or newer, otherwise disabled. |
4819 | .IP "\s-1EV_USE_LINUXAIO\s0" 4 |
4893 | .IP "\s-1EV_USE_LINUXAIO\s0" 4 |
4820 | .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" |
4821 | 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 |
4822 | 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 |
4823 | explicitly. If undefined, it will be enabled on linux, otherwise |
4902 | current limitations it has to be requested explicitly. If undefined, it |
4824 | disabled. |
4903 | will be enabled on linux, otherwise disabled. |
4825 | .IP "\s-1EV_USE_KQUEUE\s0" 4 |
4904 | .IP "\s-1EV_USE_KQUEUE\s0" 4 |
4826 | .IX Item "EV_USE_KQUEUE" |
4905 | .IX Item "EV_USE_KQUEUE" |
4827 | 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 |
4828 | \&\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, |
4829 | 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 |