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Revision 1.40 by root, Fri Dec 7 19:23:48 2007 UTC vs.
Revision 1.50 by root, Wed Dec 12 17:55:05 2007 UTC

… …
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 "2007-12-07" "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"
134libev \- a high performance full\-featured event loop written in C 134libev \- 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
264You can find out the major and minor version numbers of the library 264You can find out the major and minor \s-1ABI\s0 version numbers of the library
265you linked against by calling the functions \f(CW\*(C`ev_version_major\*(C'\fR and 265you 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
267symbols \f(CW\*(C`EV_VERSION_MAJOR\*(C'\fR and \f(CW\*(C`EV_VERSION_MINOR\*(C'\fR, which specify the 267symbols \f(CW\*(C`EV_VERSION_MAJOR\*(C'\fR and \f(CW\*(C`EV_VERSION_MINOR\*(C'\fR, which specify the
268version of the library your program was compiled against. 268version of the library your program was compiled against.
269.Sp 269.Sp
270These version numbers refer to the \s-1ABI\s0 version of the library, not the
271release version.
272.Sp
270Usually, it's a good idea to terminate if the major versions mismatch, 273Usually, it's a good idea to terminate if the major versions mismatch,
271as this indicates an incompatible change. Minor versions are usually 274as this indicates an incompatible change. Minor versions are usually
272compatible to older versions, so a larger minor version alone is usually 275compatible to older versions, so a larger minor version alone is usually
273not a problem. 276not a problem.
274.Sp 277.Sp
275Example: Make sure we haven't accidentally been linked against the wrong 278Example: Make sure we haven't accidentally been linked against the wrong
276version. 279version.
… …
634libev watchers. However, a pair of \f(CW\*(C`ev_prepare\*(C'\fR/\f(CW\*(C`ev_check\*(C'\fR watchers is 637libev watchers. However, a pair of \f(CW\*(C`ev_prepare\*(C'\fR/\f(CW\*(C`ev_check\*(C'\fR watchers is
635usually a better approach for this kind of thing. 638usually a better approach for this kind of thing.
636.Sp 639.Sp
637Here are the gory details of what \f(CW\*(C`ev_loop\*(C'\fR does: 640Here 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.
… …
889.IP "bool ev_is_pending (ev_TYPE *watcher)" 4 893.IP "bool ev_is_pending (ev_TYPE *watcher)" 4
890.IX Item "bool ev_is_pending (ev_TYPE *watcher)" 894.IX Item "bool ev_is_pending (ev_TYPE *watcher)"
891Returns a true value iff the watcher is pending, (i.e. it has outstanding 895Returns a true value iff the watcher is pending, (i.e. it has outstanding
892events but its callback has not yet been invoked). As long as a watcher 896events but its callback has not yet been invoked). As long as a watcher
893is pending (but not active) you must not call an init function on it (but 897is pending (but not active) you must not call an init function on it (but
894\&\f(CW\*(C`ev_TYPE_set\*(C'\fR is safe) and you must make sure the watcher is available to 898\&\f(CW\*(C`ev_TYPE_set\*(C'\fR is safe), you must not change its priority, and you must
895libev (e.g. you cnanot \f(CW\*(C`free ()\*(C'\fR it). 899make sure the watcher is available to libev (e.g. you cannot \f(CW\*(C`free ()\*(C'\fR
900it).
896.IP "callback ev_cb (ev_TYPE *watcher)" 4 901.IP "callback ev_cb (ev_TYPE *watcher)" 4
897.IX Item "callback ev_cb (ev_TYPE *watcher)" 902.IX Item "callback ev_cb (ev_TYPE *watcher)"
898Returns the callback currently set on the watcher. 903Returns the callback currently set on the watcher.
899.IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 904.IP "ev_cb_set (ev_TYPE *watcher, callback)" 4
900.IX Item "ev_cb_set (ev_TYPE *watcher, callback)" 905.IX Item "ev_cb_set (ev_TYPE *watcher, callback)"
… …
918watchers on the same event and make sure one is called first. 923watchers on the same event and make sure one is called first.
919.Sp 924.Sp
920If you need to suppress invocation when higher priority events are pending 925If you need to suppress invocation when higher priority events are pending
921you need to look at \f(CW\*(C`ev_idle\*(C'\fR watchers, which provide this functionality. 926you need to look at \f(CW\*(C`ev_idle\*(C'\fR watchers, which provide this functionality.
922.Sp 927.Sp
928You \fImust not\fR change the priority of a watcher as long as it is active or
929pending.
930.Sp
923The default priority used by watchers when no priority has been set is 931The default priority used by watchers when no priority has been set is
924always \f(CW0\fR, which is supposed to not be too high and not be too low :). 932always \f(CW0\fR, which is supposed to not be too high and not be too low :).
925.Sp 933.Sp
926Setting a priority outside the range of \f(CW\*(C`EV_MINPRI\*(C'\fR to \f(CW\*(C`EV_MAXPRI\*(C'\fR is 934Setting a priority outside the range of \f(CW\*(C`EV_MINPRI\*(C'\fR to \f(CW\*(C`EV_MAXPRI\*(C'\fR is
927fine, as long as you do not mind that the priority value you query might 935fine, as long as you do not mind that the priority value you query might
928or might not have been adjusted to be within valid range. 936or might not have been adjusted to be within valid range.
937.IP "ev_invoke (loop, ev_TYPE *watcher, int revents)" 4
938.IX Item "ev_invoke (loop, ev_TYPE *watcher, int revents)"
939Invoke the \f(CW\*(C`watcher\*(C'\fR with the given \f(CW\*(C`loop\*(C'\fR and \f(CW\*(C`revents\*(C'\fR. Neither
940\&\f(CW\*(C`loop\*(C'\fR nor \f(CW\*(C`revents\*(C'\fR need to be valid as long as the watcher callback
941can deal with that fact.
942.IP "int ev_clear_pending (loop, ev_TYPE *watcher)" 4
943.IX Item "int ev_clear_pending (loop, ev_TYPE *watcher)"
944If the watcher is pending, this function returns clears its pending status
945and returns its \f(CW\*(C`revents\*(C'\fR bitset (as if its callback was invoked). If the
946watcher isn't pending it does nothing and returns \f(CW0\fR.
929.Sh "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0" 947.Sh "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0"
930.IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER" 948.IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER"
931Each watcher has, by default, a member \f(CW\*(C`void *data\*(C'\fR that you can change 949Each watcher has, by default, a member \f(CW\*(C`void *data\*(C'\fR that you can change
932and read at any time, libev will completely ignore it. This can be used 950and read at any time, libev will completely ignore it. This can be used
933to associate arbitrary data with your watcher. If you need more data and 951to associate arbitrary data with your watcher. If you need more data and
… …
1047If you cannot run the fd in non-blocking mode (for example you should not 1065If you cannot run the fd in non-blocking mode (for example you should not
1048play around with an Xlib connection), then you have to seperately re-test 1066play around with an Xlib connection), then you have to seperately re-test
1049whether a file descriptor is really ready with a known-to-be good interface 1067whether a file descriptor is really ready with a known-to-be good interface
1050such as poll (fortunately in our Xlib example, Xlib already does this on 1068such as poll (fortunately in our Xlib example, Xlib already does this on
1051its own, so its quite safe to use). 1069its 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
1074Some backends (e.g kqueue, epoll) need to be told about closing a file
1075descriptor (either by calling \f(CW\*(C`close\*(C'\fR explicitly or by any other means,
1076such as \f(CW\*(C`dup\*(C'\fR). The reason is that you register interest in some file
1077descriptor, but when it goes away, the operating system will silently drop
1078this interest. If another file descriptor with the same number then is
1079registered with libev, there is no efficient way to see that this is, in
1080fact, a different file descriptor.
1081.PP
1082To avoid having to explicitly tell libev about such cases, libev follows
1083the following policy: Each time \f(CW\*(C`ev_io_set\*(C'\fR is being called, libev
1084will assume that this is potentially a new file descriptor, otherwise
1085it is assumed that the file descriptor stays the same. That means that
1086you \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
1087descriptor even if the file descriptor number itself did not change.
1088.PP
1089This is how one would do it normally anyway, the important point is that
1090the libev application should not optimise around libev but should leave
1091optimisations to libev.
1092.PP
1093\fIWatcher-Specific Functions\fR
1094.IX Subsection "Watcher-Specific Functions"
1052.IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 1095.IP "ev_io_init (ev_io *, callback, int fd, int events)" 4
1053.IX Item "ev_io_init (ev_io *, callback, int fd, int events)" 1096.IX Item "ev_io_init (ev_io *, callback, int fd, int events)"
1054.PD 0 1097.PD 0
1055.IP "ev_io_set (ev_io *, int fd, int events)" 4 1098.IP "ev_io_set (ev_io *, int fd, int events)" 4
1056.IX Item "ev_io_set (ev_io *, int fd, int events)" 1099.IX Item "ev_io_set (ev_io *, int fd, int events)"
… …
1109.Ve 1152.Ve
1110.PP 1153.PP
1111The callback is guarenteed to be invoked only when its timeout has passed, 1154The callback is guarenteed to be invoked only when its timeout has passed,
1112but if multiple timers become ready during the same loop iteration then 1155but if multiple timers become ready during the same loop iteration then
1113order of execution is undefined. 1156order of execution is undefined.
1157.PP
1158\fIWatcher-Specific Functions and Data Members\fR
1159.IX Subsection "Watcher-Specific Functions and Data Members"
1114.IP "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" 4 1160.IP "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" 4
1115.IX Item "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" 1161.IX Item "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)"
1116.PD 0 1162.PD 0
1117.IP "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)" 4 1163.IP "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)" 4
1118.IX Item "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)" 1164.IX Item "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)"
… …
1220but on wallclock time (absolute time). You can tell a periodic watcher 1266but on wallclock time (absolute time). You can tell a periodic watcher
1221to trigger \*(L"at\*(R" some specific point in time. For example, if you tell a 1267to trigger \*(L"at\*(R" some specific point in time. For example, if you tell a
1222periodic watcher to trigger in 10 seconds (by specifiying e.g. \f(CW\*(C`ev_now () 1268periodic watcher to trigger in 10 seconds (by specifiying e.g. \f(CW\*(C`ev_now ()
1223+ 10.\*(C'\fR) and then reset your system clock to the last year, then it will 1269+ 10.\*(C'\fR) and then reset your system clock to the last year, then it will
1224take a year to trigger the event (unlike an \f(CW\*(C`ev_timer\*(C'\fR, which would trigger 1270take a year to trigger the event (unlike an \f(CW\*(C`ev_timer\*(C'\fR, which would trigger
1225roughly 10 seconds later and of course not if you reset your system time 1271roughly 10 seconds later).
1226again).
1227.PP 1272.PP
1228They can also be used to implement vastly more complex timers, such as 1273They can also be used to implement vastly more complex timers, such as
1229triggering an event on eahc midnight, local time. 1274triggering an event on each midnight, local time or other, complicated,
1275rules.
1230.PP 1276.PP
1231As with timers, the callback is guarenteed to be invoked only when the 1277As with timers, the callback is guarenteed to be invoked only when the
1232time (\f(CW\*(C`at\*(C'\fR) has been passed, but if multiple periodic timers become ready 1278time (\f(CW\*(C`at\*(C'\fR) has been passed, but if multiple periodic timers become ready
1233during the same loop iteration then order of execution is undefined. 1279during the same loop iteration then order of execution is undefined.
1280.PP
1281\fIWatcher-Specific Functions and Data Members\fR
1282.IX Subsection "Watcher-Specific Functions and Data Members"
1234.IP "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" 4 1283.IP "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" 4
1235.IX Item "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" 1284.IX Item "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)"
1236.PD 0 1285.PD 0
1237.IP "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" 4 1286.IP "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" 4
1238.IX Item "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" 1287.IX Item "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)"
1239.PD 1288.PD
1240Lots of arguments, lets sort it out... There are basically three modes of 1289Lots of arguments, lets sort it out... There are basically three modes of
1241operation, and we will explain them from simplest to complex: 1290operation, and we will explain them from simplest to complex:
1242.RS 4 1291.RS 4
1243.IP "* absolute timer (interval = reschedule_cb = 0)" 4 1292.IP "* absolute timer (at = time, interval = reschedule_cb = 0)" 4
1244.IX Item "absolute timer (interval = reschedule_cb = 0)" 1293.IX Item "absolute timer (at = time, interval = reschedule_cb = 0)"
1245In this configuration the watcher triggers an event at the wallclock time 1294In this configuration the watcher triggers an event at the wallclock time
1246\&\f(CW\*(C`at\*(C'\fR and doesn't repeat. It will not adjust when a time jump occurs, 1295\&\f(CW\*(C`at\*(C'\fR and doesn't repeat. It will not adjust when a time jump occurs,
1247that is, if it is to be run at January 1st 2011 then it will run when the 1296that is, if it is to be run at January 1st 2011 then it will run when the
1248system time reaches or surpasses this time. 1297system time reaches or surpasses this time.
1249.IP "* non-repeating interval timer (interval > 0, reschedule_cb = 0)" 4 1298.IP "* non-repeating interval timer (at = offset, interval > 0, reschedule_cb = 0)" 4
1250.IX Item "non-repeating interval timer (interval > 0, reschedule_cb = 0)" 1299.IX Item "non-repeating interval timer (at = offset, interval > 0, reschedule_cb = 0)"
1251In this mode the watcher will always be scheduled to time out at the next 1300In this mode the watcher will always be scheduled to time out at the next
1252\&\f(CW\*(C`at + N * interval\*(C'\fR time (for some integer N) and then repeat, regardless 1301\&\f(CW\*(C`at + N * interval\*(C'\fR time (for some integer N, which can also be negative)
1253of any time jumps. 1302and then repeat, regardless of any time jumps.
1254.Sp 1303.Sp
1255This can be used to create timers that do not drift with respect to system 1304This can be used to create timers that do not drift with respect to system
1256time: 1305time:
1257.Sp 1306.Sp
1258.Vb 1 1307.Vb 1
… …
1265by 3600. 1314by 3600.
1266.Sp 1315.Sp
1267Another way to think about it (for the mathematically inclined) is that 1316Another way to think about it (for the mathematically inclined) is that
1268\&\f(CW\*(C`ev_periodic\*(C'\fR will try to run the callback in this mode at the next possible 1317\&\f(CW\*(C`ev_periodic\*(C'\fR will try to run the callback in this mode at the next possible
1269time where \f(CW\*(C`time = at (mod interval)\*(C'\fR, regardless of any time jumps. 1318time where \f(CW\*(C`time = at (mod interval)\*(C'\fR, regardless of any time jumps.
1319.Sp
1320For numerical stability it is preferable that the \f(CW\*(C`at\*(C'\fR value is near
1321\&\f(CW\*(C`ev_now ()\*(C'\fR (the current time), but there is no range requirement for
1322this value.
1270.IP "* manual reschedule mode (reschedule_cb = callback)" 4 1323.IP "* manual reschedule mode (at and interval ignored, reschedule_cb = callback)" 4
1271.IX Item "manual reschedule mode (reschedule_cb = callback)" 1324.IX Item "manual reschedule mode (at and interval ignored, reschedule_cb = callback)"
1272In this mode the values for \f(CW\*(C`interval\*(C'\fR and \f(CW\*(C`at\*(C'\fR are both being 1325In this mode the values for \f(CW\*(C`interval\*(C'\fR and \f(CW\*(C`at\*(C'\fR are both being
1273ignored. Instead, each time the periodic watcher gets scheduled, the 1326ignored. Instead, each time the periodic watcher gets scheduled, the
1274reschedule callback will be called with the watcher as first, and the 1327reschedule callback will be called with the watcher as first, and the
1275current time as second argument. 1328current time as second argument.
1276.Sp 1329.Sp
1277\&\s-1NOTE:\s0 \fIThis callback \s-1MUST\s0 \s-1NOT\s0 stop or destroy any periodic watcher, 1330\&\s-1NOTE:\s0 \fIThis callback \s-1MUST\s0 \s-1NOT\s0 stop or destroy any periodic watcher,
1278ever, or make any event loop modifications\fR. If you need to stop it, 1331ever, or make any event loop modifications\fR. If you need to stop it,
1279return \f(CW\*(C`now + 1e30\*(C'\fR (or so, fudge fudge) and stop it afterwards (e.g. by 1332return \f(CW\*(C`now + 1e30\*(C'\fR (or so, fudge fudge) and stop it afterwards (e.g. by
1280starting a prepare watcher). 1333starting an \f(CW\*(C`ev_prepare\*(C'\fR watcher, which is legal).
1281.Sp 1334.Sp
1282Its prototype is \f(CW\*(C`ev_tstamp (*reschedule_cb)(struct ev_periodic *w, 1335Its prototype is \f(CW\*(C`ev_tstamp (*reschedule_cb)(struct ev_periodic *w,
1283ev_tstamp now)\*(C'\fR, e.g.: 1336ev_tstamp now)\*(C'\fR, e.g.:
1284.Sp 1337.Sp
1285.Vb 4 1338.Vb 4
… …
1309.IX Item "ev_periodic_again (loop, ev_periodic *)" 1362.IX Item "ev_periodic_again (loop, ev_periodic *)"
1310Simply stops and restarts the periodic watcher again. This is only useful 1363Simply stops and restarts the periodic watcher again. This is only useful
1311when you changed some parameters or the reschedule callback would return 1364when you changed some parameters or the reschedule callback would return
1312a different time than the last time it was called (e.g. in a crond like 1365a different time than the last time it was called (e.g. in a crond like
1313program when the crontabs have changed). 1366program when the crontabs have changed).
1367.IP "ev_tstamp offset [read\-write]" 4
1368.IX Item "ev_tstamp offset [read-write]"
1369When repeating, this contains the offset value, otherwise this is the
1370absolute point in time (the \f(CW\*(C`at\*(C'\fR value passed to \f(CW\*(C`ev_periodic_set\*(C'\fR).
1371.Sp
1372Can be modified any time, but changes only take effect when the periodic
1373timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called.
1314.IP "ev_tstamp interval [read\-write]" 4 1374.IP "ev_tstamp interval [read\-write]" 4
1315.IX Item "ev_tstamp interval [read-write]" 1375.IX Item "ev_tstamp interval [read-write]"
1316The current interval value. Can be modified any time, but changes only 1376The current interval value. Can be modified any time, but changes only
1317take effect when the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being 1377take effect when the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being
1318called. 1378called.
… …
1378first watcher gets started will libev actually register a signal watcher 1438first watcher gets started will libev actually register a signal watcher
1379with the kernel (thus it coexists with your own signal handlers as long 1439with the kernel (thus it coexists with your own signal handlers as long
1380as you don't register any with libev). Similarly, when the last signal 1440as you don't register any with libev). Similarly, when the last signal
1381watcher for a signal is stopped libev will reset the signal handler to 1441watcher for a signal is stopped libev will reset the signal handler to
1382\&\s-1SIG_DFL\s0 (regardless of what it was set to before). 1442\&\s-1SIG_DFL\s0 (regardless of what it was set to before).
1443.PP
1444\fIWatcher-Specific Functions and Data Members\fR
1445.IX Subsection "Watcher-Specific Functions and Data Members"
1383.IP "ev_signal_init (ev_signal *, callback, int signum)" 4 1446.IP "ev_signal_init (ev_signal *, callback, int signum)" 4
1384.IX Item "ev_signal_init (ev_signal *, callback, int signum)" 1447.IX Item "ev_signal_init (ev_signal *, callback, int signum)"
1385.PD 0 1448.PD 0
1386.IP "ev_signal_set (ev_signal *, int signum)" 4 1449.IP "ev_signal_set (ev_signal *, int signum)" 4
1387.IX Item "ev_signal_set (ev_signal *, int signum)" 1450.IX Item "ev_signal_set (ev_signal *, int signum)"
… …
1394.ie n .Sh """ev_child"" \- watch out for process status changes" 1457.ie n .Sh """ev_child"" \- watch out for process status changes"
1395.el .Sh "\f(CWev_child\fP \- watch out for process status changes" 1458.el .Sh "\f(CWev_child\fP \- watch out for process status changes"
1396.IX Subsection "ev_child - watch out for process status changes" 1459.IX Subsection "ev_child - watch out for process status changes"
1397Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to 1460Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to
1398some child status changes (most typically when a child of yours dies). 1461some child status changes (most typically when a child of yours dies).
1462.PP
1463\fIWatcher-Specific Functions and Data Members\fR
1464.IX Subsection "Watcher-Specific Functions and Data Members"
1399.IP "ev_child_init (ev_child *, callback, int pid)" 4 1465.IP "ev_child_init (ev_child *, callback, int pid)" 4
1400.IX Item "ev_child_init (ev_child *, callback, int pid)" 1466.IX Item "ev_child_init (ev_child *, callback, int pid)"
1401.PD 0 1467.PD 0
1402.IP "ev_child_set (ev_child *, int pid)" 4 1468.IP "ev_child_set (ev_child *, int pid)" 4
1403.IX Item "ev_child_set (ev_child *, int pid)" 1469.IX Item "ev_child_set (ev_child *, int pid)"
… …
1468reader). Inotify will be used to give hints only and should not change the 1534reader). Inotify will be used to give hints only and should not change the
1469semantics of \f(CW\*(C`ev_stat\*(C'\fR watchers, which means that libev sometimes needs 1535semantics of \f(CW\*(C`ev_stat\*(C'\fR watchers, which means that libev sometimes needs
1470to fall back to regular polling again even with inotify, but changes are 1536to fall back to regular polling again even with inotify, but changes are
1471usually detected immediately, and if the file exists there will be no 1537usually detected immediately, and if the file exists there will be no
1472polling. 1538polling.
1539.PP
1540\fIWatcher-Specific Functions and Data Members\fR
1541.IX Subsection "Watcher-Specific Functions and Data Members"
1473.IP "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" 4 1542.IP "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" 4
1474.IX Item "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" 1543.IX Item "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)"
1475.PD 0 1544.PD 0
1476.IP "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" 4 1545.IP "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" 4
1477.IX Item "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" 1546.IX Item "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)"
… …
1556.PP 1625.PP
1557Apart from keeping your process non-blocking (which is a useful 1626Apart from keeping your process non-blocking (which is a useful
1558effect on its own sometimes), idle watchers are a good place to do 1627effect on its own sometimes), idle watchers are a good place to do
1559\&\*(L"pseudo\-background processing\*(R", or delay processing stuff to after the 1628\&\*(L"pseudo\-background processing\*(R", or delay processing stuff to after the
1560event loop has handled all outstanding events. 1629event loop has handled all outstanding events.
1630.PP
1631\fIWatcher-Specific Functions and Data Members\fR
1632.IX Subsection "Watcher-Specific Functions and Data Members"
1561.IP "ev_idle_init (ev_signal *, callback)" 4 1633.IP "ev_idle_init (ev_signal *, callback)" 4
1562.IX Item "ev_idle_init (ev_signal *, callback)" 1634.IX Item "ev_idle_init (ev_signal *, callback)"
1563Initialises and configures the idle watcher \- it has no parameters of any 1635Initialises and configures the idle watcher \- it has no parameters of any
1564kind. There is a \f(CW\*(C`ev_idle_set\*(C'\fR macro, but using it is utterly pointless, 1636kind. There is a \f(CW\*(C`ev_idle_set\*(C'\fR macro, but using it is utterly pointless,
1565believe me. 1637believe me.
… …
1620are ready to run (it's actually more complicated: it only runs coroutines 1692are ready to run (it's actually more complicated: it only runs coroutines
1621with priority higher than or equal to the event loop and one coroutine 1693with priority higher than or equal to the event loop and one coroutine
1622of lower priority, but only once, using idle watchers to keep the event 1694of lower priority, but only once, using idle watchers to keep the event
1623loop from blocking if lower-priority coroutines are active, thus mapping 1695loop from blocking if lower-priority coroutines are active, thus mapping
1624low-priority coroutines to idle/background tasks). 1696low-priority coroutines to idle/background tasks).
1697.PP
1698It is recommended to give \f(CW\*(C`ev_check\*(C'\fR watchers highest (\f(CW\*(C`EV_MAXPRI\*(C'\fR)
1699priority, to ensure that they are being run before any other watchers
1700after the poll. Also, \f(CW\*(C`ev_check\*(C'\fR watchers (and \f(CW\*(C`ev_prepare\*(C'\fR watchers,
1701too) should not activate (\*(L"feed\*(R") events into libev. While libev fully
1702supports this, they will be called before other \f(CW\*(C`ev_check\*(C'\fR watchers did
1703their job. As \f(CW\*(C`ev_check\*(C'\fR watchers are often used to embed other event
1704loops those other event loops might be in an unusable state until their
1705\&\f(CW\*(C`ev_check\*(C'\fR watcher ran (always remind yourself to coexist peacefully with
1706others).
1707.PP
1708\fIWatcher-Specific Functions and Data Members\fR
1709.IX Subsection "Watcher-Specific Functions and Data Members"
1625.IP "ev_prepare_init (ev_prepare *, callback)" 4 1710.IP "ev_prepare_init (ev_prepare *, callback)" 4
1626.IX Item "ev_prepare_init (ev_prepare *, callback)" 1711.IX Item "ev_prepare_init (ev_prepare *, callback)"
1627.PD 0 1712.PD 0
1628.IP "ev_check_init (ev_check *, callback)" 4 1713.IP "ev_check_init (ev_check *, callback)" 4
1629.IX Item "ev_check_init (ev_check *, callback)" 1714.IX Item "ev_check_init (ev_check *, callback)"
1630.PD 1715.PD
1631Initialises and configures the prepare or check watcher \- they have no 1716Initialises and configures the prepare or check watcher \- they have no
1632parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR 1717parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR
1633macros, but using them is utterly, utterly and completely pointless. 1718macros, but using them is utterly, utterly and completely pointless.
1634.PP 1719.PP
1635Example: To include a library such as adns, you would add \s-1IO\s0 watchers 1720There are a number of principal ways to embed other event loops or modules
1636and a timeout watcher in a prepare handler, as required by libadns, and 1721into libev. Here are some ideas on how to include libadns into libev
1722(there is a Perl module named \f(CW\*(C`EV::ADNS\*(C'\fR that does this, which you could
1723use for an actually working example. Another Perl module named \f(CW\*(C`EV::Glib\*(C'\fR
1724embeds a Glib main context into libev, and finally, \f(CW\*(C`Glib::EV\*(C'\fR embeds \s-1EV\s0
1725into the Glib event loop).
1726.PP
1727Method 1: Add \s-1IO\s0 watchers and a timeout watcher in a prepare handler,
1637in a check watcher, destroy them and call into libadns. What follows is 1728and in a check watcher, destroy them and call into libadns. What follows
1638pseudo-code only of course: 1729is pseudo-code only of course. This requires you to either use a low
1730priority for the check watcher or use \f(CW\*(C`ev_clear_pending\*(C'\fR explicitly, as
1731the callbacks for the IO/timeout watchers might not have been called yet.
1639.PP 1732.PP
1640.Vb 2 1733.Vb 2
1641\& static ev_io iow [nfd]; 1734\& static ev_io iow [nfd];
1642\& static ev_timer tw; 1735\& static ev_timer tw;
1643.Ve 1736.Ve
1644.PP 1737.PP
1645.Vb 9 1738.Vb 4
1646\& static void 1739\& static void
1647\& io_cb (ev_loop *loop, ev_io *w, int revents) 1740\& io_cb (ev_loop *loop, ev_io *w, int revents)
1648\& { 1741\& {
1649\& // set the relevant poll flags
1650\& // could also call adns_processreadable etc. here
1651\& struct pollfd *fd = (struct pollfd *)w->data;
1652\& if (revents & EV_READ ) fd->revents |= fd->events & POLLIN;
1653\& if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT;
1654\& } 1742\& }
1655.Ve 1743.Ve
1656.PP 1744.PP
1657.Vb 8 1745.Vb 8
1658\& // create io watchers for each fd and a timer before blocking 1746\& // create io watchers for each fd and a timer before blocking
… …
1670\& ev_timer_init (&tw, 0, timeout * 1e-3); 1758\& ev_timer_init (&tw, 0, timeout * 1e-3);
1671\& ev_timer_start (loop, &tw); 1759\& ev_timer_start (loop, &tw);
1672.Ve 1760.Ve
1673.PP 1761.PP
1674.Vb 6 1762.Vb 6
1675\& // create on ev_io per pollfd 1763\& // create one ev_io per pollfd
1676\& for (int i = 0; i < nfd; ++i) 1764\& for (int i = 0; i < nfd; ++i)
1677\& { 1765\& {
1678\& ev_io_init (iow + i, io_cb, fds [i].fd, 1766\& ev_io_init (iow + i, io_cb, fds [i].fd,
1679\& ((fds [i].events & POLLIN ? EV_READ : 0) 1767\& ((fds [i].events & POLLIN ? EV_READ : 0)
1680\& | (fds [i].events & POLLOUT ? EV_WRITE : 0))); 1768\& | (fds [i].events & POLLOUT ? EV_WRITE : 0)));
1681.Ve 1769.Ve
1682.PP 1770.PP
1683.Vb 5 1771.Vb 4
1684\& fds [i].revents = 0; 1772\& fds [i].revents = 0;
1685\& iow [i].data = fds + i;
1686\& ev_io_start (loop, iow + i); 1773\& ev_io_start (loop, iow + i);
1687\& } 1774\& }
1688\& } 1775\& }
1689.Ve 1776.Ve
1690.PP 1777.PP
… …
1694\& adns_check_cb (ev_loop *loop, ev_check *w, int revents) 1781\& adns_check_cb (ev_loop *loop, ev_check *w, int revents)
1695\& { 1782\& {
1696\& ev_timer_stop (loop, &tw); 1783\& ev_timer_stop (loop, &tw);
1697.Ve 1784.Ve
1698.PP 1785.PP
1699.Vb 2 1786.Vb 8
1700\& for (int i = 0; i < nfd; ++i) 1787\& for (int i = 0; i < nfd; ++i)
1788\& {
1789\& // set the relevant poll flags
1790\& // could also call adns_processreadable etc. here
1791\& struct pollfd *fd = fds + i;
1792\& int revents = ev_clear_pending (iow + i);
1793\& if (revents & EV_READ ) fd->revents |= fd->events & POLLIN;
1794\& if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT;
1795.Ve
1796.PP
1797.Vb 3
1798\& // now stop the watcher
1701\& ev_io_stop (loop, iow + i); 1799\& ev_io_stop (loop, iow + i);
1800\& }
1702.Ve 1801.Ve
1703.PP 1802.PP
1704.Vb 2 1803.Vb 2
1705\& adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); 1804\& adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop));
1805\& }
1806.Ve
1807.PP
1808Method 2: This would be just like method 1, but you run \f(CW\*(C`adns_afterpoll\*(C'\fR
1809in the prepare watcher and would dispose of the check watcher.
1810.PP
1811Method 3: If the module to be embedded supports explicit event
1812notification (adns does), you can also make use of the actual watcher
1813callbacks, and only destroy/create the watchers in the prepare watcher.
1814.PP
1815.Vb 5
1816\& static void
1817\& timer_cb (EV_P_ ev_timer *w, int revents)
1818\& {
1819\& adns_state ads = (adns_state)w->data;
1820\& update_now (EV_A);
1821.Ve
1822.PP
1823.Vb 2
1824\& adns_processtimeouts (ads, &tv_now);
1825\& }
1826.Ve
1827.PP
1828.Vb 5
1829\& static void
1830\& io_cb (EV_P_ ev_io *w, int revents)
1831\& {
1832\& adns_state ads = (adns_state)w->data;
1833\& update_now (EV_A);
1834.Ve
1835.PP
1836.Vb 3
1837\& if (revents & EV_READ ) adns_processreadable (ads, w->fd, &tv_now);
1838\& if (revents & EV_WRITE) adns_processwriteable (ads, w->fd, &tv_now);
1839\& }
1840.Ve
1841.PP
1842.Vb 1
1843\& // do not ever call adns_afterpoll
1844.Ve
1845.PP
1846Method 4: Do not use a prepare or check watcher because the module you
1847want to embed is too inflexible to support it. Instead, youc na override
1848their poll function. The drawback with this solution is that the main
1849loop is now no longer controllable by \s-1EV\s0. The \f(CW\*(C`Glib::EV\*(C'\fR module does
1850this.
1851.PP
1852.Vb 4
1853\& static gint
1854\& event_poll_func (GPollFD *fds, guint nfds, gint timeout)
1855\& {
1856\& int got_events = 0;
1857.Ve
1858.PP
1859.Vb 2
1860\& for (n = 0; n < nfds; ++n)
1861\& // create/start io watcher that sets the relevant bits in fds[n] and increment got_events
1862.Ve
1863.PP
1864.Vb 2
1865\& if (timeout >= 0)
1866\& // create/start timer
1867.Ve
1868.PP
1869.Vb 2
1870\& // poll
1871\& ev_loop (EV_A_ 0);
1872.Ve
1873.PP
1874.Vb 3
1875\& // stop timer again
1876\& if (timeout >= 0)
1877\& ev_timer_stop (EV_A_ &to);
1878.Ve
1879.PP
1880.Vb 3
1881\& // stop io watchers again - their callbacks should have set
1882\& for (n = 0; n < nfds; ++n)
1883\& ev_io_stop (EV_A_ iow [n]);
1884.Ve
1885.PP
1886.Vb 2
1887\& return got_events;
1706\& } 1888\& }
1707.Ve 1889.Ve
1708.ie n .Sh """ev_embed"" \- when one backend isn't enough..." 1890.ie n .Sh """ev_embed"" \- when one backend isn't enough..."
1709.el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..." 1891.el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..."
1710.IX Subsection "ev_embed - when one backend isn't enough..." 1892.IX Subsection "ev_embed - when one backend isn't enough..."
… …
1779\& ev_embed_start (loop_hi, &embed); 1961\& ev_embed_start (loop_hi, &embed);
1780\& } 1962\& }
1781\& else 1963\& else
1782\& loop_lo = loop_hi; 1964\& loop_lo = loop_hi;
1783.Ve 1965.Ve
1966.PP
1967\fIWatcher-Specific Functions and Data Members\fR
1968.IX Subsection "Watcher-Specific Functions and Data Members"
1784.IP "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 1969.IP "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" 4
1785.IX Item "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" 1970.IX Item "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)"
1786.PD 0 1971.PD 0
1787.IP "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 1972.IP "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" 4
1788.IX Item "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)" 1973.IX Item "ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)"
… …
1894.PP 2079.PP
1895.Vb 1 2080.Vb 1
1896\& #include <ev++.h> 2081\& #include <ev++.h>
1897.Ve 2082.Ve
1898.PP 2083.PP
1899(it is not installed by default). This automatically includes \fIev.h\fR 2084This automatically includes \fIev.h\fR and puts all of its definitions (many
1900and puts all of its definitions (many of them macros) into the global 2085of them macros) into the global namespace. All \*(C+ specific things are
1901namespace. All \*(C+ specific things are put into the \f(CW\*(C`ev\*(C'\fR namespace. 2086put into the \f(CW\*(C`ev\*(C'\fR namespace. It should support all the same embedding
2087options as \fIev.h\fR, most notably \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR.
1902.PP 2088.PP
1903It should support all the same embedding options as \fIev.h\fR, most notably 2089Care has been taken to keep the overhead low. The only data member the \*(C+
1904\&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. 2090classes add (compared to plain C\-style watchers) is the event loop pointer
2091that the watcher is associated with (or no additional members at all if
2092you disable \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR when embedding libev).
2093.PP
2094Currently, functions, and static and non-static member functions can be
2095used as callbacks. Other types should be easy to add as long as they only
2096need one additional pointer for context. If you need support for other
2097types of functors please contact the author (preferably after implementing
2098it).
1905.PP 2099.PP
1906Here is a list of things available in the \f(CW\*(C`ev\*(C'\fR namespace: 2100Here is a list of things available in the \f(CW\*(C`ev\*(C'\fR namespace:
1907.ie n .IP """ev::READ""\fR, \f(CW""ev::WRITE"" etc." 4 2101.ie n .IP """ev::READ""\fR, \f(CW""ev::WRITE"" etc." 4
1908.el .IP "\f(CWev::READ\fR, \f(CWev::WRITE\fR etc." 4 2102.el .IP "\f(CWev::READ\fR, \f(CWev::WRITE\fR etc." 4
1909.IX Item "ev::READ, ev::WRITE etc." 2103.IX Item "ev::READ, ev::WRITE etc."
… …
1921which is called \f(CW\*(C`ev::sig\*(C'\fR to avoid clashes with the \f(CW\*(C`signal\*(C'\fR macro 2115which is called \f(CW\*(C`ev::sig\*(C'\fR to avoid clashes with the \f(CW\*(C`signal\*(C'\fR macro
1922defines by many implementations. 2116defines by many implementations.
1923.Sp 2117.Sp
1924All of those classes have these methods: 2118All of those classes have these methods:
1925.RS 4 2119.RS 4
1926.IP "ev::TYPE::TYPE (object *, object::method *)" 4 2120.IP "ev::TYPE::TYPE ()" 4
1927.IX Item "ev::TYPE::TYPE (object *, object::method *)" 2121.IX Item "ev::TYPE::TYPE ()"
1928.PD 0 2122.PD 0
1929.IP "ev::TYPE::TYPE (object *, object::method *, struct ev_loop *)" 4 2123.IP "ev::TYPE::TYPE (struct ev_loop *)" 4
1930.IX Item "ev::TYPE::TYPE (object *, object::method *, struct ev_loop *)" 2124.IX Item "ev::TYPE::TYPE (struct ev_loop *)"
1931.IP "ev::TYPE::~TYPE" 4 2125.IP "ev::TYPE::~TYPE" 4
1932.IX Item "ev::TYPE::~TYPE" 2126.IX Item "ev::TYPE::~TYPE"
1933.PD 2127.PD
1934The constructor takes a pointer to an object and a method pointer to 2128The constructor (optionally) takes an event loop to associate the watcher
1935the event handler callback to call in this class. The constructor calls 2129with. If it is omitted, it will use \f(CW\*(C`EV_DEFAULT\*(C'\fR.
1936\&\f(CW\*(C`ev_init\*(C'\fR for you, which means you have to call the \f(CW\*(C`set\*(C'\fR method 2130.Sp
1937before starting it. If you do not specify a loop then the constructor 2131The constructor calls \f(CW\*(C`ev_init\*(C'\fR for you, which means you have to call the
1938automatically associates the default loop with this watcher. 2132\&\f(CW\*(C`set\*(C'\fR method before starting it.
2133.Sp
2134It will not set a callback, however: You have to call the templated \f(CW\*(C`set\*(C'\fR
2135method to set a callback before you can start the watcher.
2136.Sp
2137(The reason why you have to use a method is a limitation in \*(C+ which does
2138not allow explicit template arguments for constructors).
1939.Sp 2139.Sp
1940The destructor automatically stops the watcher if it is active. 2140The destructor automatically stops the watcher if it is active.
2141.IP "w\->set<class, &class::method> (object *)" 4
2142.IX Item "w->set<class, &class::method> (object *)"
2143This method sets the callback method to call. The method has to have a
2144signature of \f(CW\*(C`void (*)(ev_TYPE &, int)\*(C'\fR, it receives the watcher as
2145first argument and the \f(CW\*(C`revents\*(C'\fR as second. The object must be given as
2146parameter and is stored in the \f(CW\*(C`data\*(C'\fR member of the watcher.
2147.Sp
2148This method synthesizes efficient thunking code to call your method from
2149the C callback that libev requires. If your compiler can inline your
2150callback (i.e. it is visible to it at the place of the \f(CW\*(C`set\*(C'\fR call and
2151your compiler is good :), then the method will be fully inlined into the
2152thunking function, making it as fast as a direct C callback.
2153.Sp
2154Example: simple class declaration and watcher initialisation
2155.Sp
2156.Vb 4
2157\& struct myclass
2158\& {
2159\& void io_cb (ev::io &w, int revents) { }
2160\& }
2161.Ve
2162.Sp
2163.Vb 3
2164\& myclass obj;
2165\& ev::io iow;
2166\& iow.set <myclass, &myclass::io_cb> (&obj);
2167.Ve
2168.IP "w\->set<function> (void *data = 0)" 4
2169.IX Item "w->set<function> (void *data = 0)"
2170Also sets a callback, but uses a static method or plain function as
2171callback. The optional \f(CW\*(C`data\*(C'\fR argument will be stored in the watcher's
2172\&\f(CW\*(C`data\*(C'\fR member and is free for you to use.
2173.Sp
2174The prototype of the \f(CW\*(C`function\*(C'\fR must be \f(CW\*(C`void (*)(ev::TYPE &w, int)\*(C'\fR.
2175.Sp
2176See the method\-\f(CW\*(C`set\*(C'\fR above for more details.
2177.Sp
2178Example:
2179.Sp
2180.Vb 2
2181\& static void io_cb (ev::io &w, int revents) { }
2182\& iow.set <io_cb> ();
2183.Ve
1941.IP "w\->set (struct ev_loop *)" 4 2184.IP "w\->set (struct ev_loop *)" 4
1942.IX Item "w->set (struct ev_loop *)" 2185.IX Item "w->set (struct ev_loop *)"
1943Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only 2186Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only
1944do this when the watcher is inactive (and not pending either). 2187do this when the watcher is inactive (and not pending either).
1945.IP "w\->set ([args])" 4 2188.IP "w\->set ([args])" 4
1946.IX Item "w->set ([args])" 2189.IX Item "w->set ([args])"
1947Basically the same as \f(CW\*(C`ev_TYPE_set\*(C'\fR, with the same args. Must be 2190Basically the same as \f(CW\*(C`ev_TYPE_set\*(C'\fR, with the same args. Must be
1948called at least once. Unlike the C counterpart, an active watcher gets 2191called at least once. Unlike the C counterpart, an active watcher gets
1949automatically stopped and restarted. 2192automatically stopped and restarted when reconfiguring it with this
2193method.
1950.IP "w\->start ()" 4 2194.IP "w\->start ()" 4
1951.IX Item "w->start ()" 2195.IX Item "w->start ()"
1952Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument as the 2196Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument, as the
1953constructor already takes the loop. 2197constructor already stores the event loop.
1954.IP "w\->stop ()" 4 2198.IP "w\->stop ()" 4
1955.IX Item "w->stop ()" 2199.IX Item "w->stop ()"
1956Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument. 2200Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument.
1957.ie n .IP "w\->again () ""ev::timer""\fR, \f(CW""ev::periodic"" only" 4 2201.ie n .IP "w\->again () ""ev::timer""\fR, \f(CW""ev::periodic"" only" 4
1958.el .IP "w\->again () \f(CWev::timer\fR, \f(CWev::periodic\fR only" 4 2202.el .IP "w\->again () \f(CWev::timer\fR, \f(CWev::periodic\fR only" 4
… …
1984.Vb 2 2228.Vb 2
1985\& myclass (); 2229\& myclass ();
1986\& } 2230\& }
1987.Ve 2231.Ve
1988.PP 2232.PP
1989.Vb 6 2233.Vb 4
1990\& myclass::myclass (int fd) 2234\& myclass::myclass (int fd)
1991\& : io (this, &myclass::io_cb),
1992\& idle (this, &myclass::idle_cb)
1993\& { 2235\& {
2236\& io .set <myclass, &myclass::io_cb > (this);
2237\& idle.set <myclass, &myclass::idle_cb> (this);
2238.Ve
2239.PP
2240.Vb 2
1994\& io.start (fd, ev::READ); 2241\& io.start (fd, ev::READ);
1995\& } 2242\& }
1996.Ve 2243.Ve
1997.SH "MACRO MAGIC" 2244.SH "MACRO MAGIC"
1998.IX Header "MACRO MAGIC" 2245.IX Header "MACRO MAGIC"

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