… | |
… | |
127 | .\} |
127 | .\} |
128 | .rm #[ #] #H #V #F C |
128 | .rm #[ #] #H #V #F C |
129 | .\" ======================================================================== |
129 | .\" ======================================================================== |
130 | .\" |
130 | .\" |
131 | .IX Title ""<STANDARD INPUT>" 1" |
131 | .IX Title ""<STANDARD INPUT>" 1" |
132 | .TH "<STANDARD INPUT>" 1 "2007-12-08" "perl v5.8.8" "User Contributed Perl Documentation" |
132 | .TH "<STANDARD INPUT>" 1 "2007-12-12" "perl v5.8.8" "User Contributed Perl Documentation" |
133 | .SH "NAME" |
133 | .SH "NAME" |
134 | libev \- a high performance full\-featured event loop written in C |
134 | libev \- a high performance full\-featured event loop written in C |
135 | .SH "SYNOPSIS" |
135 | .SH "SYNOPSIS" |
136 | .IX Header "SYNOPSIS" |
136 | .IX Header "SYNOPSIS" |
137 | .Vb 1 |
137 | .Vb 1 |
… | |
… | |
259 | .IX Item "int ev_version_major ()" |
259 | .IX Item "int ev_version_major ()" |
260 | .PD 0 |
260 | .PD 0 |
261 | .IP "int ev_version_minor ()" 4 |
261 | .IP "int ev_version_minor ()" 4 |
262 | .IX Item "int ev_version_minor ()" |
262 | .IX Item "int ev_version_minor ()" |
263 | .PD |
263 | .PD |
264 | You can find out the major and minor version numbers of the library |
264 | You can find out the major and minor \s-1ABI\s0 version numbers of the library |
265 | you linked against by calling the functions \f(CW\*(C`ev_version_major\*(C'\fR and |
265 | you linked against by calling the functions \f(CW\*(C`ev_version_major\*(C'\fR and |
266 | \&\f(CW\*(C`ev_version_minor\*(C'\fR. If you want, you can compare against the global |
266 | \&\f(CW\*(C`ev_version_minor\*(C'\fR. If you want, you can compare against the global |
267 | symbols \f(CW\*(C`EV_VERSION_MAJOR\*(C'\fR and \f(CW\*(C`EV_VERSION_MINOR\*(C'\fR, which specify the |
267 | symbols \f(CW\*(C`EV_VERSION_MAJOR\*(C'\fR and \f(CW\*(C`EV_VERSION_MINOR\*(C'\fR, which specify the |
268 | version of the library your program was compiled against. |
268 | version of the library your program was compiled against. |
269 | .Sp |
269 | .Sp |
|
|
270 | These version numbers refer to the \s-1ABI\s0 version of the library, not the |
|
|
271 | release version. |
|
|
272 | .Sp |
270 | Usually, it's a good idea to terminate if the major versions mismatch, |
273 | Usually, it's a good idea to terminate if the major versions mismatch, |
271 | as this indicates an incompatible change. Minor versions are usually |
274 | as this indicates an incompatible change. Minor versions are usually |
272 | compatible to older versions, so a larger minor version alone is usually |
275 | compatible to older versions, so a larger minor version alone is usually |
273 | not a problem. |
276 | not a problem. |
274 | .Sp |
277 | .Sp |
275 | Example: Make sure we haven't accidentally been linked against the wrong |
278 | Example: Make sure we haven't accidentally been linked against the wrong |
276 | version. |
279 | version. |
… | |
… | |
634 | libev watchers. However, a pair of \f(CW\*(C`ev_prepare\*(C'\fR/\f(CW\*(C`ev_check\*(C'\fR watchers is |
637 | libev watchers. However, a pair of \f(CW\*(C`ev_prepare\*(C'\fR/\f(CW\*(C`ev_check\*(C'\fR watchers is |
635 | usually a better approach for this kind of thing. |
638 | usually a better approach for this kind of thing. |
636 | .Sp |
639 | .Sp |
637 | Here are the gory details of what \f(CW\*(C`ev_loop\*(C'\fR does: |
640 | Here are the gory details of what \f(CW\*(C`ev_loop\*(C'\fR does: |
638 | .Sp |
641 | .Sp |
639 | .Vb 18 |
642 | .Vb 19 |
|
|
643 | \& - Before the first iteration, call any pending watchers. |
640 | \& * If there are no active watchers (reference count is zero), return. |
644 | \& * If there are no active watchers (reference count is zero), return. |
641 | \& - Queue prepare watchers and then call all outstanding watchers. |
645 | \& - Queue all prepare watchers and then call all outstanding watchers. |
642 | \& - If we have been forked, recreate the kernel state. |
646 | \& - If we have been forked, recreate the kernel state. |
643 | \& - Update the kernel state with all outstanding changes. |
647 | \& - Update the kernel state with all outstanding changes. |
644 | \& - Update the "event loop time". |
648 | \& - Update the "event loop time". |
645 | \& - Calculate for how long to block. |
649 | \& - Calculate for how long to block. |
646 | \& - Block the process, waiting for any events. |
650 | \& - Block the process, waiting for any events. |
… | |
… | |
1061 | If you cannot run the fd in non-blocking mode (for example you should not |
1065 | If you cannot run the fd in non-blocking mode (for example you should not |
1062 | play around with an Xlib connection), then you have to seperately re-test |
1066 | play around with an Xlib connection), then you have to seperately re-test |
1063 | whether a file descriptor is really ready with a known-to-be good interface |
1067 | whether a file descriptor is really ready with a known-to-be good interface |
1064 | such as poll (fortunately in our Xlib example, Xlib already does this on |
1068 | such as poll (fortunately in our Xlib example, Xlib already does this on |
1065 | its own, so its quite safe to use). |
1069 | its own, so its quite safe to use). |
|
|
1070 | .PP |
|
|
1071 | \fIThe special problem of disappearing file descriptors\fR |
|
|
1072 | .IX Subsection "The special problem of disappearing file descriptors" |
|
|
1073 | .PP |
|
|
1074 | Some backends (e.g kqueue, epoll) need to be told about closing a file |
|
|
1075 | descriptor (either by calling \f(CW\*(C`close\*(C'\fR explicitly or by any other means, |
|
|
1076 | such as \f(CW\*(C`dup\*(C'\fR). The reason is that you register interest in some file |
|
|
1077 | descriptor, but when it goes away, the operating system will silently drop |
|
|
1078 | this interest. If another file descriptor with the same number then is |
|
|
1079 | registered with libev, there is no efficient way to see that this is, in |
|
|
1080 | fact, a different file descriptor. |
|
|
1081 | .PP |
|
|
1082 | To avoid having to explicitly tell libev about such cases, libev follows |
|
|
1083 | the following policy: Each time \f(CW\*(C`ev_io_set\*(C'\fR is being called, libev |
|
|
1084 | will assume that this is potentially a new file descriptor, otherwise |
|
|
1085 | it is assumed that the file descriptor stays the same. That means that |
|
|
1086 | you \fIhave\fR to call \f(CW\*(C`ev_io_set\*(C'\fR (or \f(CW\*(C`ev_io_init\*(C'\fR) when you change the |
|
|
1087 | descriptor even if the file descriptor number itself did not change. |
|
|
1088 | .PP |
|
|
1089 | This is how one would do it normally anyway, the important point is that |
|
|
1090 | the libev application should not optimise around libev but should leave |
|
|
1091 | optimisations to libev. |
1066 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
1092 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
1067 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
1093 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
1068 | .PD 0 |
1094 | .PD 0 |
1069 | .IP "ev_io_set (ev_io *, int fd, int events)" 4 |
1095 | .IP "ev_io_set (ev_io *, int fd, int events)" 4 |
1070 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
1096 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
… | |
… | |
1234 | but on wallclock time (absolute time). You can tell a periodic watcher |
1260 | but on wallclock time (absolute time). You can tell a periodic watcher |
1235 | to trigger \*(L"at\*(R" some specific point in time. For example, if you tell a |
1261 | to trigger \*(L"at\*(R" some specific point in time. For example, if you tell a |
1236 | periodic watcher to trigger in 10 seconds (by specifiying e.g. \f(CW\*(C`ev_now () |
1262 | periodic watcher to trigger in 10 seconds (by specifiying e.g. \f(CW\*(C`ev_now () |
1237 | + 10.\*(C'\fR) and then reset your system clock to the last year, then it will |
1263 | + 10.\*(C'\fR) and then reset your system clock to the last year, then it will |
1238 | take a year to trigger the event (unlike an \f(CW\*(C`ev_timer\*(C'\fR, which would trigger |
1264 | take a year to trigger the event (unlike an \f(CW\*(C`ev_timer\*(C'\fR, which would trigger |
1239 | roughly 10 seconds later and of course not if you reset your system time |
1265 | roughly 10 seconds later). |
1240 | again). |
|
|
1241 | .PP |
1266 | .PP |
1242 | They can also be used to implement vastly more complex timers, such as |
1267 | They can also be used to implement vastly more complex timers, such as |
1243 | triggering an event on eahc midnight, local time. |
1268 | triggering an event on each midnight, local time or other, complicated, |
|
|
1269 | rules. |
1244 | .PP |
1270 | .PP |
1245 | As with timers, the callback is guarenteed to be invoked only when the |
1271 | As with timers, the callback is guarenteed to be invoked only when the |
1246 | time (\f(CW\*(C`at\*(C'\fR) has been passed, but if multiple periodic timers become ready |
1272 | time (\f(CW\*(C`at\*(C'\fR) has been passed, but if multiple periodic timers become ready |
1247 | during the same loop iteration then order of execution is undefined. |
1273 | during the same loop iteration then order of execution is undefined. |
1248 | .IP "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" 4 |
1274 | .IP "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" 4 |
… | |
… | |
1252 | .IX Item "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" |
1278 | .IX Item "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" |
1253 | .PD |
1279 | .PD |
1254 | Lots of arguments, lets sort it out... There are basically three modes of |
1280 | Lots of arguments, lets sort it out... There are basically three modes of |
1255 | operation, and we will explain them from simplest to complex: |
1281 | operation, and we will explain them from simplest to complex: |
1256 | .RS 4 |
1282 | .RS 4 |
1257 | .IP "* absolute timer (interval = reschedule_cb = 0)" 4 |
1283 | .IP "* absolute timer (at = time, interval = reschedule_cb = 0)" 4 |
1258 | .IX Item "absolute timer (interval = reschedule_cb = 0)" |
1284 | .IX Item "absolute timer (at = time, interval = reschedule_cb = 0)" |
1259 | In this configuration the watcher triggers an event at the wallclock time |
1285 | In this configuration the watcher triggers an event at the wallclock time |
1260 | \&\f(CW\*(C`at\*(C'\fR and doesn't repeat. It will not adjust when a time jump occurs, |
1286 | \&\f(CW\*(C`at\*(C'\fR and doesn't repeat. It will not adjust when a time jump occurs, |
1261 | that is, if it is to be run at January 1st 2011 then it will run when the |
1287 | that is, if it is to be run at January 1st 2011 then it will run when the |
1262 | system time reaches or surpasses this time. |
1288 | system time reaches or surpasses this time. |
1263 | .IP "* non-repeating interval timer (interval > 0, reschedule_cb = 0)" 4 |
1289 | .IP "* non-repeating interval timer (at = offset, interval > 0, reschedule_cb = 0)" 4 |
1264 | .IX Item "non-repeating interval timer (interval > 0, reschedule_cb = 0)" |
1290 | .IX Item "non-repeating interval timer (at = offset, interval > 0, reschedule_cb = 0)" |
1265 | In this mode the watcher will always be scheduled to time out at the next |
1291 | In this mode the watcher will always be scheduled to time out at the next |
1266 | \&\f(CW\*(C`at + N * interval\*(C'\fR time (for some integer N) and then repeat, regardless |
1292 | \&\f(CW\*(C`at + N * interval\*(C'\fR time (for some integer N, which can also be negative) |
1267 | of any time jumps. |
1293 | and then repeat, regardless of any time jumps. |
1268 | .Sp |
1294 | .Sp |
1269 | This can be used to create timers that do not drift with respect to system |
1295 | This can be used to create timers that do not drift with respect to system |
1270 | time: |
1296 | time: |
1271 | .Sp |
1297 | .Sp |
1272 | .Vb 1 |
1298 | .Vb 1 |
… | |
… | |
1279 | by 3600. |
1305 | by 3600. |
1280 | .Sp |
1306 | .Sp |
1281 | Another way to think about it (for the mathematically inclined) is that |
1307 | Another way to think about it (for the mathematically inclined) is that |
1282 | \&\f(CW\*(C`ev_periodic\*(C'\fR will try to run the callback in this mode at the next possible |
1308 | \&\f(CW\*(C`ev_periodic\*(C'\fR will try to run the callback in this mode at the next possible |
1283 | time where \f(CW\*(C`time = at (mod interval)\*(C'\fR, regardless of any time jumps. |
1309 | time where \f(CW\*(C`time = at (mod interval)\*(C'\fR, regardless of any time jumps. |
|
|
1310 | .Sp |
|
|
1311 | For numerical stability it is preferable that the \f(CW\*(C`at\*(C'\fR value is near |
|
|
1312 | \&\f(CW\*(C`ev_now ()\*(C'\fR (the current time), but there is no range requirement for |
|
|
1313 | this value. |
1284 | .IP "* manual reschedule mode (reschedule_cb = callback)" 4 |
1314 | .IP "* manual reschedule mode (at and interval ignored, reschedule_cb = callback)" 4 |
1285 | .IX Item "manual reschedule mode (reschedule_cb = callback)" |
1315 | .IX Item "manual reschedule mode (at and interval ignored, reschedule_cb = callback)" |
1286 | In this mode the values for \f(CW\*(C`interval\*(C'\fR and \f(CW\*(C`at\*(C'\fR are both being |
1316 | In this mode the values for \f(CW\*(C`interval\*(C'\fR and \f(CW\*(C`at\*(C'\fR are both being |
1287 | ignored. Instead, each time the periodic watcher gets scheduled, the |
1317 | ignored. Instead, each time the periodic watcher gets scheduled, the |
1288 | reschedule callback will be called with the watcher as first, and the |
1318 | reschedule callback will be called with the watcher as first, and the |
1289 | current time as second argument. |
1319 | current time as second argument. |
1290 | .Sp |
1320 | .Sp |
1291 | \&\s-1NOTE:\s0 \fIThis callback \s-1MUST\s0 \s-1NOT\s0 stop or destroy any periodic watcher, |
1321 | \&\s-1NOTE:\s0 \fIThis callback \s-1MUST\s0 \s-1NOT\s0 stop or destroy any periodic watcher, |
1292 | ever, or make any event loop modifications\fR. If you need to stop it, |
1322 | ever, or make any event loop modifications\fR. If you need to stop it, |
1293 | return \f(CW\*(C`now + 1e30\*(C'\fR (or so, fudge fudge) and stop it afterwards (e.g. by |
1323 | return \f(CW\*(C`now + 1e30\*(C'\fR (or so, fudge fudge) and stop it afterwards (e.g. by |
1294 | starting a prepare watcher). |
1324 | starting an \f(CW\*(C`ev_prepare\*(C'\fR watcher, which is legal). |
1295 | .Sp |
1325 | .Sp |
1296 | Its prototype is \f(CW\*(C`ev_tstamp (*reschedule_cb)(struct ev_periodic *w, |
1326 | Its prototype is \f(CW\*(C`ev_tstamp (*reschedule_cb)(struct ev_periodic *w, |
1297 | ev_tstamp now)\*(C'\fR, e.g.: |
1327 | ev_tstamp now)\*(C'\fR, e.g.: |
1298 | .Sp |
1328 | .Sp |
1299 | .Vb 4 |
1329 | .Vb 4 |
… | |
… | |
1323 | .IX Item "ev_periodic_again (loop, ev_periodic *)" |
1353 | .IX Item "ev_periodic_again (loop, ev_periodic *)" |
1324 | Simply stops and restarts the periodic watcher again. This is only useful |
1354 | Simply stops and restarts the periodic watcher again. This is only useful |
1325 | when you changed some parameters or the reschedule callback would return |
1355 | when you changed some parameters or the reschedule callback would return |
1326 | a different time than the last time it was called (e.g. in a crond like |
1356 | a different time than the last time it was called (e.g. in a crond like |
1327 | program when the crontabs have changed). |
1357 | program when the crontabs have changed). |
|
|
1358 | .IP "ev_tstamp offset [read\-write]" 4 |
|
|
1359 | .IX Item "ev_tstamp offset [read-write]" |
|
|
1360 | When repeating, this contains the offset value, otherwise this is the |
|
|
1361 | absolute point in time (the \f(CW\*(C`at\*(C'\fR value passed to \f(CW\*(C`ev_periodic_set\*(C'\fR). |
|
|
1362 | .Sp |
|
|
1363 | Can be modified any time, but changes only take effect when the periodic |
|
|
1364 | timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called. |
1328 | .IP "ev_tstamp interval [read\-write]" 4 |
1365 | .IP "ev_tstamp interval [read\-write]" 4 |
1329 | .IX Item "ev_tstamp interval [read-write]" |
1366 | .IX Item "ev_tstamp interval [read-write]" |
1330 | The current interval value. Can be modified any time, but changes only |
1367 | The current interval value. Can be modified any time, but changes only |
1331 | take effect when the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being |
1368 | take effect when the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being |
1332 | called. |
1369 | called. |
… | |
… | |
1634 | are ready to run (it's actually more complicated: it only runs coroutines |
1671 | are ready to run (it's actually more complicated: it only runs coroutines |
1635 | with priority higher than or equal to the event loop and one coroutine |
1672 | with priority higher than or equal to the event loop and one coroutine |
1636 | of lower priority, but only once, using idle watchers to keep the event |
1673 | of lower priority, but only once, using idle watchers to keep the event |
1637 | loop from blocking if lower-priority coroutines are active, thus mapping |
1674 | loop from blocking if lower-priority coroutines are active, thus mapping |
1638 | low-priority coroutines to idle/background tasks). |
1675 | low-priority coroutines to idle/background tasks). |
|
|
1676 | .PP |
|
|
1677 | It is recommended to give \f(CW\*(C`ev_check\*(C'\fR watchers highest (\f(CW\*(C`EV_MAXPRI\*(C'\fR) |
|
|
1678 | priority, to ensure that they are being run before any other watchers |
|
|
1679 | after the poll. Also, \f(CW\*(C`ev_check\*(C'\fR watchers (and \f(CW\*(C`ev_prepare\*(C'\fR watchers, |
|
|
1680 | too) should not activate (\*(L"feed\*(R") events into libev. While libev fully |
|
|
1681 | supports this, they will be called before other \f(CW\*(C`ev_check\*(C'\fR watchers did |
|
|
1682 | their job. As \f(CW\*(C`ev_check\*(C'\fR watchers are often used to embed other event |
|
|
1683 | loops those other event loops might be in an unusable state until their |
|
|
1684 | \&\f(CW\*(C`ev_check\*(C'\fR watcher ran (always remind yourself to coexist peacefully with |
|
|
1685 | others). |
1639 | .IP "ev_prepare_init (ev_prepare *, callback)" 4 |
1686 | .IP "ev_prepare_init (ev_prepare *, callback)" 4 |
1640 | .IX Item "ev_prepare_init (ev_prepare *, callback)" |
1687 | .IX Item "ev_prepare_init (ev_prepare *, callback)" |
1641 | .PD 0 |
1688 | .PD 0 |
1642 | .IP "ev_check_init (ev_check *, callback)" 4 |
1689 | .IP "ev_check_init (ev_check *, callback)" 4 |
1643 | .IX Item "ev_check_init (ev_check *, callback)" |
1690 | .IX Item "ev_check_init (ev_check *, callback)" |
1644 | .PD |
1691 | .PD |
1645 | Initialises and configures the prepare or check watcher \- they have no |
1692 | Initialises and configures the prepare or check watcher \- they have no |
1646 | parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR |
1693 | parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR |
1647 | macros, but using them is utterly, utterly and completely pointless. |
1694 | macros, but using them is utterly, utterly and completely pointless. |
1648 | .PP |
1695 | .PP |
1649 | Example: To include a library such as adns, you would add \s-1IO\s0 watchers |
1696 | There are a number of principal ways to embed other event loops or modules |
1650 | and a timeout watcher in a prepare handler, as required by libadns, and |
1697 | into libev. Here are some ideas on how to include libadns into libev |
|
|
1698 | (there is a Perl module named \f(CW\*(C`EV::ADNS\*(C'\fR that does this, which you could |
|
|
1699 | use for an actually working example. Another Perl module named \f(CW\*(C`EV::Glib\*(C'\fR |
|
|
1700 | embeds a Glib main context into libev, and finally, \f(CW\*(C`Glib::EV\*(C'\fR embeds \s-1EV\s0 |
|
|
1701 | into the Glib event loop). |
|
|
1702 | .PP |
|
|
1703 | Method 1: Add \s-1IO\s0 watchers and a timeout watcher in a prepare handler, |
1651 | in a check watcher, destroy them and call into libadns. What follows is |
1704 | and in a check watcher, destroy them and call into libadns. What follows |
1652 | pseudo-code only of course: |
1705 | is pseudo-code only of course. This requires you to either use a low |
|
|
1706 | priority for the check watcher or use \f(CW\*(C`ev_clear_pending\*(C'\fR explicitly, as |
|
|
1707 | the callbacks for the IO/timeout watchers might not have been called yet. |
1653 | .PP |
1708 | .PP |
1654 | .Vb 2 |
1709 | .Vb 2 |
1655 | \& static ev_io iow [nfd]; |
1710 | \& static ev_io iow [nfd]; |
1656 | \& static ev_timer tw; |
1711 | \& static ev_timer tw; |
1657 | .Ve |
1712 | .Ve |
1658 | .PP |
1713 | .PP |
1659 | .Vb 9 |
1714 | .Vb 4 |
1660 | \& static void |
1715 | \& static void |
1661 | \& io_cb (ev_loop *loop, ev_io *w, int revents) |
1716 | \& io_cb (ev_loop *loop, ev_io *w, int revents) |
1662 | \& { |
1717 | \& { |
1663 | \& // set the relevant poll flags |
|
|
1664 | \& // could also call adns_processreadable etc. here |
|
|
1665 | \& struct pollfd *fd = (struct pollfd *)w->data; |
|
|
1666 | \& if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
|
|
1667 | \& if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
|
|
1668 | \& } |
1718 | \& } |
1669 | .Ve |
1719 | .Ve |
1670 | .PP |
1720 | .PP |
1671 | .Vb 8 |
1721 | .Vb 8 |
1672 | \& // create io watchers for each fd and a timer before blocking |
1722 | \& // create io watchers for each fd and a timer before blocking |
… | |
… | |
1684 | \& ev_timer_init (&tw, 0, timeout * 1e-3); |
1734 | \& ev_timer_init (&tw, 0, timeout * 1e-3); |
1685 | \& ev_timer_start (loop, &tw); |
1735 | \& ev_timer_start (loop, &tw); |
1686 | .Ve |
1736 | .Ve |
1687 | .PP |
1737 | .PP |
1688 | .Vb 6 |
1738 | .Vb 6 |
1689 | \& // create on ev_io per pollfd |
1739 | \& // create one ev_io per pollfd |
1690 | \& for (int i = 0; i < nfd; ++i) |
1740 | \& for (int i = 0; i < nfd; ++i) |
1691 | \& { |
1741 | \& { |
1692 | \& ev_io_init (iow + i, io_cb, fds [i].fd, |
1742 | \& ev_io_init (iow + i, io_cb, fds [i].fd, |
1693 | \& ((fds [i].events & POLLIN ? EV_READ : 0) |
1743 | \& ((fds [i].events & POLLIN ? EV_READ : 0) |
1694 | \& | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
1744 | \& | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
1695 | .Ve |
1745 | .Ve |
1696 | .PP |
1746 | .PP |
1697 | .Vb 5 |
1747 | .Vb 4 |
1698 | \& fds [i].revents = 0; |
1748 | \& fds [i].revents = 0; |
1699 | \& iow [i].data = fds + i; |
|
|
1700 | \& ev_io_start (loop, iow + i); |
1749 | \& ev_io_start (loop, iow + i); |
1701 | \& } |
1750 | \& } |
1702 | \& } |
1751 | \& } |
1703 | .Ve |
1752 | .Ve |
1704 | .PP |
1753 | .PP |
… | |
… | |
1708 | \& adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
1757 | \& adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
1709 | \& { |
1758 | \& { |
1710 | \& ev_timer_stop (loop, &tw); |
1759 | \& ev_timer_stop (loop, &tw); |
1711 | .Ve |
1760 | .Ve |
1712 | .PP |
1761 | .PP |
1713 | .Vb 2 |
1762 | .Vb 8 |
1714 | \& for (int i = 0; i < nfd; ++i) |
1763 | \& for (int i = 0; i < nfd; ++i) |
|
|
1764 | \& { |
|
|
1765 | \& // set the relevant poll flags |
|
|
1766 | \& // could also call adns_processreadable etc. here |
|
|
1767 | \& struct pollfd *fd = fds + i; |
|
|
1768 | \& int revents = ev_clear_pending (iow + i); |
|
|
1769 | \& if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
|
|
1770 | \& if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
|
|
1771 | .Ve |
|
|
1772 | .PP |
|
|
1773 | .Vb 3 |
|
|
1774 | \& // now stop the watcher |
1715 | \& ev_io_stop (loop, iow + i); |
1775 | \& ev_io_stop (loop, iow + i); |
|
|
1776 | \& } |
1716 | .Ve |
1777 | .Ve |
1717 | .PP |
1778 | .PP |
1718 | .Vb 2 |
1779 | .Vb 2 |
1719 | \& adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
1780 | \& adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
|
|
1781 | \& } |
|
|
1782 | .Ve |
|
|
1783 | .PP |
|
|
1784 | Method 2: This would be just like method 1, but you run \f(CW\*(C`adns_afterpoll\*(C'\fR |
|
|
1785 | in the prepare watcher and would dispose of the check watcher. |
|
|
1786 | .PP |
|
|
1787 | Method 3: If the module to be embedded supports explicit event |
|
|
1788 | notification (adns does), you can also make use of the actual watcher |
|
|
1789 | callbacks, and only destroy/create the watchers in the prepare watcher. |
|
|
1790 | .PP |
|
|
1791 | .Vb 5 |
|
|
1792 | \& static void |
|
|
1793 | \& timer_cb (EV_P_ ev_timer *w, int revents) |
|
|
1794 | \& { |
|
|
1795 | \& adns_state ads = (adns_state)w->data; |
|
|
1796 | \& update_now (EV_A); |
|
|
1797 | .Ve |
|
|
1798 | .PP |
|
|
1799 | .Vb 2 |
|
|
1800 | \& adns_processtimeouts (ads, &tv_now); |
|
|
1801 | \& } |
|
|
1802 | .Ve |
|
|
1803 | .PP |
|
|
1804 | .Vb 5 |
|
|
1805 | \& static void |
|
|
1806 | \& io_cb (EV_P_ ev_io *w, int revents) |
|
|
1807 | \& { |
|
|
1808 | \& adns_state ads = (adns_state)w->data; |
|
|
1809 | \& update_now (EV_A); |
|
|
1810 | .Ve |
|
|
1811 | .PP |
|
|
1812 | .Vb 3 |
|
|
1813 | \& if (revents & EV_READ ) adns_processreadable (ads, w->fd, &tv_now); |
|
|
1814 | \& if (revents & EV_WRITE) adns_processwriteable (ads, w->fd, &tv_now); |
|
|
1815 | \& } |
|
|
1816 | .Ve |
|
|
1817 | .PP |
|
|
1818 | .Vb 1 |
|
|
1819 | \& // do not ever call adns_afterpoll |
|
|
1820 | .Ve |
|
|
1821 | .PP |
|
|
1822 | Method 4: Do not use a prepare or check watcher because the module you |
|
|
1823 | want to embed is too inflexible to support it. Instead, youc na override |
|
|
1824 | their poll function. The drawback with this solution is that the main |
|
|
1825 | loop is now no longer controllable by \s-1EV\s0. The \f(CW\*(C`Glib::EV\*(C'\fR module does |
|
|
1826 | this. |
|
|
1827 | .PP |
|
|
1828 | .Vb 4 |
|
|
1829 | \& static gint |
|
|
1830 | \& event_poll_func (GPollFD *fds, guint nfds, gint timeout) |
|
|
1831 | \& { |
|
|
1832 | \& int got_events = 0; |
|
|
1833 | .Ve |
|
|
1834 | .PP |
|
|
1835 | .Vb 2 |
|
|
1836 | \& for (n = 0; n < nfds; ++n) |
|
|
1837 | \& // create/start io watcher that sets the relevant bits in fds[n] and increment got_events |
|
|
1838 | .Ve |
|
|
1839 | .PP |
|
|
1840 | .Vb 2 |
|
|
1841 | \& if (timeout >= 0) |
|
|
1842 | \& // create/start timer |
|
|
1843 | .Ve |
|
|
1844 | .PP |
|
|
1845 | .Vb 2 |
|
|
1846 | \& // poll |
|
|
1847 | \& ev_loop (EV_A_ 0); |
|
|
1848 | .Ve |
|
|
1849 | .PP |
|
|
1850 | .Vb 3 |
|
|
1851 | \& // stop timer again |
|
|
1852 | \& if (timeout >= 0) |
|
|
1853 | \& ev_timer_stop (EV_A_ &to); |
|
|
1854 | .Ve |
|
|
1855 | .PP |
|
|
1856 | .Vb 3 |
|
|
1857 | \& // stop io watchers again - their callbacks should have set |
|
|
1858 | \& for (n = 0; n < nfds; ++n) |
|
|
1859 | \& ev_io_stop (EV_A_ iow [n]); |
|
|
1860 | .Ve |
|
|
1861 | .PP |
|
|
1862 | .Vb 2 |
|
|
1863 | \& return got_events; |
1720 | \& } |
1864 | \& } |
1721 | .Ve |
1865 | .Ve |
1722 | .ie n .Sh """ev_embed"" \- when one backend isn't enough..." |
1866 | .ie n .Sh """ev_embed"" \- when one backend isn't enough..." |
1723 | .el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..." |
1867 | .el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..." |
1724 | .IX Subsection "ev_embed - when one backend isn't enough..." |
1868 | .IX Subsection "ev_embed - when one backend isn't enough..." |