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Comparing libev/ev.3 (file contents):
Revision 1.45 by root, Sat Dec 8 22:11:14 2007 UTC vs.
Revision 1.47 by root, Sun Dec 9 19:46:56 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 "2007-12-08" "perl v5.8.8" "User Contributed Perl Documentation" 132.TH "<STANDARD INPUT>" 1 "2007-12-09" "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-1API/ABI\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-1API\s0 and \s-1ABI\s0 version of the library, not
271the release 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.
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1235but on wallclock time (absolute time). You can tell a periodic watcher 1238but on wallclock time (absolute time). You can tell a periodic watcher
1236to trigger \*(L"at\*(R" some specific point in time. For example, if you tell a 1239to trigger \*(L"at\*(R" some specific point in time. For example, if you tell a
1237periodic watcher to trigger in 10 seconds (by specifiying e.g. \f(CW\*(C`ev_now () 1240periodic watcher to trigger in 10 seconds (by specifiying e.g. \f(CW\*(C`ev_now ()
1238+ 10.\*(C'\fR) and then reset your system clock to the last year, then it will 1241+ 10.\*(C'\fR) and then reset your system clock to the last year, then it will
1239take a year to trigger the event (unlike an \f(CW\*(C`ev_timer\*(C'\fR, which would trigger 1242take a year to trigger the event (unlike an \f(CW\*(C`ev_timer\*(C'\fR, which would trigger
1240roughly 10 seconds later and of course not if you reset your system time 1243roughly 10 seconds later).
1241again).
1242.PP 1244.PP
1243They can also be used to implement vastly more complex timers, such as 1245They can also be used to implement vastly more complex timers, such as
1244triggering an event on eahc midnight, local time. 1246triggering an event on each midnight, local time or other, complicated,
1247rules.
1245.PP 1248.PP
1246As with timers, the callback is guarenteed to be invoked only when the 1249As with timers, the callback is guarenteed to be invoked only when the
1247time (\f(CW\*(C`at\*(C'\fR) has been passed, but if multiple periodic timers become ready 1250time (\f(CW\*(C`at\*(C'\fR) has been passed, but if multiple periodic timers become ready
1248during the same loop iteration then order of execution is undefined. 1251during the same loop iteration then order of execution is undefined.
1249.IP "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" 4 1252.IP "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" 4
… …
1253.IX Item "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)" 1256.IX Item "ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)"
1254.PD 1257.PD
1255Lots of arguments, lets sort it out... There are basically three modes of 1258Lots of arguments, lets sort it out... There are basically three modes of
1256operation, and we will explain them from simplest to complex: 1259operation, and we will explain them from simplest to complex:
1257.RS 4 1260.RS 4
1258.IP "* absolute timer (interval = reschedule_cb = 0)" 4 1261.IP "* absolute timer (at = time, interval = reschedule_cb = 0)" 4
1259.IX Item "absolute timer (interval = reschedule_cb = 0)" 1262.IX Item "absolute timer (at = time, interval = reschedule_cb = 0)"
1260In this configuration the watcher triggers an event at the wallclock time 1263In this configuration the watcher triggers an event at the wallclock time
1261\&\f(CW\*(C`at\*(C'\fR and doesn't repeat. It will not adjust when a time jump occurs, 1264\&\f(CW\*(C`at\*(C'\fR and doesn't repeat. It will not adjust when a time jump occurs,
1262that is, if it is to be run at January 1st 2011 then it will run when the 1265that is, if it is to be run at January 1st 2011 then it will run when the
1263system time reaches or surpasses this time. 1266system time reaches or surpasses this time.
1264.IP "* non-repeating interval timer (interval > 0, reschedule_cb = 0)" 4 1267.IP "* non-repeating interval timer (at = offset, interval > 0, reschedule_cb = 0)" 4
1265.IX Item "non-repeating interval timer (interval > 0, reschedule_cb = 0)" 1268.IX Item "non-repeating interval timer (at = offset, interval > 0, reschedule_cb = 0)"
1266In this mode the watcher will always be scheduled to time out at the next 1269In this mode the watcher will always be scheduled to time out at the next
1267\&\f(CW\*(C`at + N * interval\*(C'\fR time (for some integer N) and then repeat, regardless 1270\&\f(CW\*(C`at + N * interval\*(C'\fR time (for some integer N, which can also be negative)
1268of any time jumps. 1271and then repeat, regardless of any time jumps.
1269.Sp 1272.Sp
1270This can be used to create timers that do not drift with respect to system 1273This can be used to create timers that do not drift with respect to system
1271time: 1274time:
1272.Sp 1275.Sp
1273.Vb 1 1276.Vb 1
… …
1280by 3600. 1283by 3600.
1281.Sp 1284.Sp
1282Another way to think about it (for the mathematically inclined) is that 1285Another way to think about it (for the mathematically inclined) is that
1283\&\f(CW\*(C`ev_periodic\*(C'\fR will try to run the callback in this mode at the next possible 1286\&\f(CW\*(C`ev_periodic\*(C'\fR will try to run the callback in this mode at the next possible
1284time where \f(CW\*(C`time = at (mod interval)\*(C'\fR, regardless of any time jumps. 1287time where \f(CW\*(C`time = at (mod interval)\*(C'\fR, regardless of any time jumps.
1288.Sp
1289For numerical stability it is preferable that the \f(CW\*(C`at\*(C'\fR value is near
1290\&\f(CW\*(C`ev_now ()\*(C'\fR (the current time), but there is no range requirement for
1291this value.
1285.IP "* manual reschedule mode (reschedule_cb = callback)" 4 1292.IP "* manual reschedule mode (at and interval ignored, reschedule_cb = callback)" 4
1286.IX Item "manual reschedule mode (reschedule_cb = callback)" 1293.IX Item "manual reschedule mode (at and interval ignored, reschedule_cb = callback)"
1287In this mode the values for \f(CW\*(C`interval\*(C'\fR and \f(CW\*(C`at\*(C'\fR are both being 1294In this mode the values for \f(CW\*(C`interval\*(C'\fR and \f(CW\*(C`at\*(C'\fR are both being
1288ignored. Instead, each time the periodic watcher gets scheduled, the 1295ignored. Instead, each time the periodic watcher gets scheduled, the
1289reschedule callback will be called with the watcher as first, and the 1296reschedule callback will be called with the watcher as first, and the
1290current time as second argument. 1297current time as second argument.
1291.Sp 1298.Sp
1292\&\s-1NOTE:\s0 \fIThis callback \s-1MUST\s0 \s-1NOT\s0 stop or destroy any periodic watcher, 1299\&\s-1NOTE:\s0 \fIThis callback \s-1MUST\s0 \s-1NOT\s0 stop or destroy any periodic watcher,
1293ever, or make any event loop modifications\fR. If you need to stop it, 1300ever, or make any event loop modifications\fR. If you need to stop it,
1294return \f(CW\*(C`now + 1e30\*(C'\fR (or so, fudge fudge) and stop it afterwards (e.g. by 1301return \f(CW\*(C`now + 1e30\*(C'\fR (or so, fudge fudge) and stop it afterwards (e.g. by
1295starting a prepare watcher). 1302starting an \f(CW\*(C`ev_prepare\*(C'\fR watcher, which is legal).
1296.Sp 1303.Sp
1297Its prototype is \f(CW\*(C`ev_tstamp (*reschedule_cb)(struct ev_periodic *w, 1304Its prototype is \f(CW\*(C`ev_tstamp (*reschedule_cb)(struct ev_periodic *w,
1298ev_tstamp now)\*(C'\fR, e.g.: 1305ev_tstamp now)\*(C'\fR, e.g.:
1299.Sp 1306.Sp
1300.Vb 4 1307.Vb 4
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1324.IX Item "ev_periodic_again (loop, ev_periodic *)" 1331.IX Item "ev_periodic_again (loop, ev_periodic *)"
1325Simply stops and restarts the periodic watcher again. This is only useful 1332Simply stops and restarts the periodic watcher again. This is only useful
1326when you changed some parameters or the reschedule callback would return 1333when you changed some parameters or the reschedule callback would return
1327a different time than the last time it was called (e.g. in a crond like 1334a different time than the last time it was called (e.g. in a crond like
1328program when the crontabs have changed). 1335program when the crontabs have changed).
1336.IP "ev_tstamp offset [read\-write]" 4
1337.IX Item "ev_tstamp offset [read-write]"
1338When repeating, this contains the offset value, otherwise this is the
1339absolute point in time (the \f(CW\*(C`at\*(C'\fR value passed to \f(CW\*(C`ev_periodic_set\*(C'\fR).
1340.Sp
1341Can be modified any time, but changes only take effect when the periodic
1342timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called.
1329.IP "ev_tstamp interval [read\-write]" 4 1343.IP "ev_tstamp interval [read\-write]" 4
1330.IX Item "ev_tstamp interval [read-write]" 1344.IX Item "ev_tstamp interval [read-write]"
1331The current interval value. Can be modified any time, but changes only 1345The current interval value. Can be modified any time, but changes only
1332take effect when the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being 1346take effect when the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being
1333called. 1347called.

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