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Revision 1.58 by root, Sat Dec 22 16:53:56 2007 UTC vs.
Revision 1.59 by root, Tue Dec 25 07:16:53 2007 UTC

… …
127.\} 127.\}
128.rm #[ #] #H #V #F C 128.rm #[ #] #H #V #F C
129.\" ======================================================================== 129.\" ========================================================================
130.\" 130.\"
131.IX Title "EV 1" 131.IX Title "EV 1"
132.TH EV 1 "2007-12-22" "perl v5.8.8" "User Contributed Perl Documentation" 132.TH EV 1 "2007-12-25" "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
138\& #include <ev.h> 138\& #include <ev.h>
139.Ve 139.Ve
140.SH "EXAMPLE PROGRAM" 140.Sh "\s-1EXAMPLE\s0 \s-1PROGRAM\s0"
141.IX Header "EXAMPLE PROGRAM" 141.IX Subsection "EXAMPLE PROGRAM"
142.Vb 1 142.Vb 1
143\& #include <ev.h> 143\& #include <ev.h>
144.Ve 144.Ve
145.PP 145.PP
146.Vb 2 146.Vb 2
… …
212.PP 212.PP
213You register interest in certain events by registering so-called \fIevent 213You register interest in certain events by registering so-called \fIevent
214watchers\fR, which are relatively small C structures you initialise with the 214watchers\fR, which are relatively small C structures you initialise with the
215details of the event, and then hand it over to libev by \fIstarting\fR the 215details of the event, and then hand it over to libev by \fIstarting\fR the
216watcher. 216watcher.
217.SH "FEATURES" 217.Sh "\s-1FEATURES\s0"
218.IX Header "FEATURES" 218.IX Subsection "FEATURES"
219Libev supports \f(CW\*(C`select\*(C'\fR, \f(CW\*(C`poll\*(C'\fR, the Linux-specific \f(CW\*(C`epoll\*(C'\fR, the 219Libev supports \f(CW\*(C`select\*(C'\fR, \f(CW\*(C`poll\*(C'\fR, the Linux-specific \f(CW\*(C`epoll\*(C'\fR, the
220BSD-specific \f(CW\*(C`kqueue\*(C'\fR and the Solaris-specific event port mechanisms 220BSD-specific \f(CW\*(C`kqueue\*(C'\fR and the Solaris-specific event port mechanisms
221for file descriptor events (\f(CW\*(C`ev_io\*(C'\fR), the Linux \f(CW\*(C`inotify\*(C'\fR interface 221for file descriptor events (\f(CW\*(C`ev_io\*(C'\fR), the Linux \f(CW\*(C`inotify\*(C'\fR interface
222(for \f(CW\*(C`ev_stat\*(C'\fR), relative timers (\f(CW\*(C`ev_timer\*(C'\fR), absolute timers 222(for \f(CW\*(C`ev_stat\*(C'\fR), relative timers (\f(CW\*(C`ev_timer\*(C'\fR), absolute timers
223with customised rescheduling (\f(CW\*(C`ev_periodic\*(C'\fR), synchronous signals 223with customised rescheduling (\f(CW\*(C`ev_periodic\*(C'\fR), synchronous signals
… …
228(\f(CW\*(C`ev_fork\*(C'\fR). 228(\f(CW\*(C`ev_fork\*(C'\fR).
229.PP 229.PP
230It also is quite fast (see this 230It also is quite fast (see this
231benchmark comparing it to libevent 231benchmark comparing it to libevent
232for example). 232for example).
233.SH "CONVENTIONS" 233.Sh "\s-1CONVENTIONS\s0"
234.IX Header "CONVENTIONS" 234.IX Subsection "CONVENTIONS"
235Libev is very configurable. In this manual the default configuration will 235Libev is very configurable. In this manual the default configuration will
236be described, which supports multiple event loops. For more info about 236be described, which supports multiple event loops. For more info about
237various configuration options please have a look at \fB\s-1EMBED\s0\fR section in 237various configuration options please have a look at \fB\s-1EMBED\s0\fR section in
238this manual. If libev was configured without support for multiple event 238this manual. If libev was configured without support for multiple event
239loops, then all functions taking an initial argument of name \f(CW\*(C`loop\*(C'\fR 239loops, then all functions taking an initial argument of name \f(CW\*(C`loop\*(C'\fR
240(which is always of type \f(CW\*(C`struct ev_loop *\*(C'\fR) will not have this argument. 240(which is always of type \f(CW\*(C`struct ev_loop *\*(C'\fR) will not have this argument.
241.SH "TIME REPRESENTATION" 241.Sh "\s-1TIME\s0 \s-1REPRESENTATION\s0"
242.IX Header "TIME REPRESENTATION" 242.IX Subsection "TIME REPRESENTATION"
243Libev represents time as a single floating point number, representing the 243Libev represents time as a single floating point number, representing the
244(fractional) number of seconds since the (\s-1POSIX\s0) epoch (somewhere near 244(fractional) number of seconds since the (\s-1POSIX\s0) epoch (somewhere near
245the beginning of 1970, details are complicated, don't ask). This type is 245the beginning of 1970, details are complicated, don't ask). This type is
246called \f(CW\*(C`ev_tstamp\*(C'\fR, which is what you should use too. It usually aliases 246called \f(CW\*(C`ev_tstamp\*(C'\fR, which is what you should use too. It usually aliases
247to the \f(CW\*(C`double\*(C'\fR type in C, and when you need to do any calculations on 247to the \f(CW\*(C`double\*(C'\fR type in C, and when you need to do any calculations on
… …
1138In general you can register as many read and/or write event watchers per 1138In general you can register as many read and/or write event watchers per
1139fd as you want (as long as you don't confuse yourself). Setting all file 1139fd as you want (as long as you don't confuse yourself). Setting all file
1140descriptors to non-blocking mode is also usually a good idea (but not 1140descriptors to non-blocking mode is also usually a good idea (but not
1141required if you know what you are doing). 1141required if you know what you are doing).
1142.PP 1142.PP
1143You have to be careful with dup'ed file descriptors, though. Some backends
1144(the linux epoll backend is a notable example) cannot handle dup'ed file
1145descriptors correctly if you register interest in two or more fds pointing
1146to the same underlying file/socket/etc. description (that is, they share
1147the same underlying \*(L"file open\*(R").
1148.PP
1149If you must do this, then force the use of a known-to-be-good backend 1143If you must do this, then force the use of a known-to-be-good backend
1150(at the time of this writing, this includes only \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR and 1144(at the time of this writing, this includes only \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR and
1151\&\f(CW\*(C`EVBACKEND_POLL\*(C'\fR). 1145\&\f(CW\*(C`EVBACKEND_POLL\*(C'\fR).
1152.PP 1146.PP
1153Another thing you have to watch out for is that it is quite easy to 1147Another thing you have to watch out for is that it is quite easy to
… …
1189.PP 1183.PP
1190\fIThe special problem of dup'ed file descriptors\fR 1184\fIThe special problem of dup'ed file descriptors\fR
1191.IX Subsection "The special problem of dup'ed file descriptors" 1185.IX Subsection "The special problem of dup'ed file descriptors"
1192.PP 1186.PP
1193Some backends (e.g. epoll), cannot register events for file descriptors, 1187Some backends (e.g. epoll), cannot register events for file descriptors,
1194but only events for the underlying file descriptions. That menas when you 1188but only events for the underlying file descriptions. That means when you
1195have \f(CW\*(C`dup ()\*(C'\fR'ed file descriptors and register events for them, only one 1189have \f(CW\*(C`dup ()\*(C'\fR'ed file descriptors or weirder constellations, and register
1196file descriptor might actually receive events. 1190events for them, only one file descriptor might actually receive events.
1197.PP 1191.PP
1198There is no workaorund possible except not registering events 1192There is no workaround possible except not registering events
1199for potentially \f(CW\*(C`dup ()\*(C'\fR'ed file descriptors or to resort to 1193for potentially \f(CW\*(C`dup ()\*(C'\fR'ed file descriptors, or to resort to
1200\&\f(CW\*(C`EVBACKEND_SELECT\*(C'\fR or \f(CW\*(C`EVBACKEND_POLL\*(C'\fR. 1194\&\f(CW\*(C`EVBACKEND_SELECT\*(C'\fR or \f(CW\*(C`EVBACKEND_POLL\*(C'\fR.
1201.PP 1195.PP
1202\fIThe special problem of fork\fR 1196\fIThe special problem of fork\fR
1203.IX Subsection "The special problem of fork" 1197.IX Subsection "The special problem of fork"
1204.PP 1198.PP
… …
1659reader). Inotify will be used to give hints only and should not change the 1653reader). Inotify will be used to give hints only and should not change the
1660semantics of \f(CW\*(C`ev_stat\*(C'\fR watchers, which means that libev sometimes needs 1654semantics of \f(CW\*(C`ev_stat\*(C'\fR watchers, which means that libev sometimes needs
1661to fall back to regular polling again even with inotify, but changes are 1655to fall back to regular polling again even with inotify, but changes are
1662usually detected immediately, and if the file exists there will be no 1656usually detected immediately, and if the file exists there will be no
1663polling. 1657polling.
1658.PP
1659\fIInotify\fR
1660.IX Subsection "Inotify"
1661.PP
1662When \f(CW\*(C`inotify (7)\*(C'\fR support has been compiled into libev (generally only
1663available on Linux) and present at runtime, it will be used to speed up
1664change detection where possible. The inotify descriptor will be created lazily
1665when the first \f(CW\*(C`ev_stat\*(C'\fR watcher is being started.
1666.PP
1667Inotify presense does not change the semantics of \f(CW\*(C`ev_stat\*(C'\fR watchers
1668except that changes might be detected earlier, and in some cases, to avoid
1669making regular \f(CW\*(C`stat\*(C'\fR calls. Even in the presense of inotify support
1670there are many cases where libev has to resort to regular \f(CW\*(C`stat\*(C'\fR polling.
1671.PP
1672(There is no support for kqueue, as apparently it cannot be used to
1673implement this functionality, due to the requirement of having a file
1674descriptor open on the object at all times).
1675.PP
1676\fIThe special problem of stat time resolution\fR
1677.IX Subsection "The special problem of stat time resolution"
1678.PP
1679The \f(CW\*(C`stat ()\*(C'\fR syscall only supports full-second resolution portably, and
1680even on systems where the resolution is higher, many filesystems still
1681only support whole seconds.
1682.PP
1683That means that, if the time is the only thing that changes, you might
1684miss updates: on the first update, \f(CW\*(C`ev_stat\*(C'\fR detects a change and calls
1685your callback, which does something. When there is another update within
1686the same second, \f(CW\*(C`ev_stat\*(C'\fR will be unable to detect it.
1687.PP
1688The solution to this is to delay acting on a change for a second (or till
1689the next second boundary), using a roughly one-second delay \f(CW\*(C`ev_timer\*(C'\fR
1690(\f(CW\*(C`ev_timer_set (w, 0., 1.01); ev_timer_again (loop, w)\*(C'\fR). The \f(CW.01\fR
1691is added to work around small timing inconsistencies of some operating
1692systems.
1664.PP 1693.PP
1665\fIWatcher-Specific Functions and Data Members\fR 1694\fIWatcher-Specific Functions and Data Members\fR
1666.IX Subsection "Watcher-Specific Functions and Data Members" 1695.IX Subsection "Watcher-Specific Functions and Data Members"
1667.IP "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" 4 1696.IP "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" 4
1668.IX Item "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" 1697.IX Item "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)"
… …
1700The specified interval. 1729The specified interval.
1701.IP "const char *path [read\-only]" 4 1730.IP "const char *path [read\-only]" 4
1702.IX Item "const char *path [read-only]" 1731.IX Item "const char *path [read-only]"
1703The filesystem path that is being watched. 1732The filesystem path that is being watched.
1704.PP 1733.PP
1734\fIExamples\fR
1735.IX Subsection "Examples"
1736.PP
1705Example: Watch \f(CW\*(C`/etc/passwd\*(C'\fR for attribute changes. 1737Example: Watch \f(CW\*(C`/etc/passwd\*(C'\fR for attribute changes.
1706.PP 1738.PP
1707.Vb 15 1739.Vb 15
1708\& static void 1740\& static void
1709\& passwd_cb (struct ev_loop *loop, ev_stat *w, int revents) 1741\& passwd_cb (struct ev_loop *loop, ev_stat *w, int revents)
… …
1726\& ... 1758\& ...
1727\& ev_stat passwd; 1759\& ev_stat passwd;
1728.Ve 1760.Ve
1729.PP 1761.PP
1730.Vb 2 1762.Vb 2
1731\& ev_stat_init (&passwd, passwd_cb, "/etc/passwd"); 1763\& ev_stat_init (&passwd, passwd_cb, "/etc/passwd", 0.);
1732\& ev_stat_start (loop, &passwd); 1764\& ev_stat_start (loop, &passwd);
1765.Ve
1766.PP
1767Example: Like above, but additionally use a one-second delay so we do not
1768miss updates (however, frequent updates will delay processing, too, so
1769one might do the work both on \f(CW\*(C`ev_stat\*(C'\fR callback invocation \fIand\fR on
1770\&\f(CW\*(C`ev_timer\*(C'\fR callback invocation).
1771.PP
1772.Vb 2
1773\& static ev_stat passwd;
1774\& static ev_timer timer;
1775.Ve
1776.PP
1777.Vb 4
1778\& static void
1779\& timer_cb (EV_P_ ev_timer *w, int revents)
1780\& {
1781\& ev_timer_stop (EV_A_ w);
1782.Ve
1783.PP
1784.Vb 2
1785\& /* now it's one second after the most recent passwd change */
1786\& }
1787.Ve
1788.PP
1789.Vb 6
1790\& static void
1791\& stat_cb (EV_P_ ev_stat *w, int revents)
1792\& {
1793\& /* reset the one-second timer */
1794\& ev_timer_again (EV_A_ &timer);
1795\& }
1796.Ve
1797.PP
1798.Vb 4
1799\& ...
1800\& ev_stat_init (&passwd, stat_cb, "/etc/passwd", 0.);
1801\& ev_stat_start (loop, &passwd);
1802\& ev_timer_init (&timer, timer_cb, 0., 1.01);
1733.Ve 1803.Ve
1734.ie n .Sh """ev_idle"" \- when you've got nothing better to do..." 1804.ie n .Sh """ev_idle"" \- when you've got nothing better to do..."
1735.el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do..." 1805.el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do..."
1736.IX Subsection "ev_idle - when you've got nothing better to do..." 1806.IX Subsection "ev_idle - when you've got nothing better to do..."
1737Idle watchers trigger events when no other events of the same or higher 1807Idle watchers trigger events when no other events of the same or higher
… …
2633interface to speed up \f(CW\*(C`ev_stat\*(C'\fR watchers. Its actual availability will 2703interface to speed up \f(CW\*(C`ev_stat\*(C'\fR watchers. Its actual availability will
2634be detected at runtime. 2704be detected at runtime.
2635.IP "\s-1EV_H\s0" 4 2705.IP "\s-1EV_H\s0" 4
2636.IX Item "EV_H" 2706.IX Item "EV_H"
2637The name of the \fIev.h\fR header file used to include it. The default if 2707The name of the \fIev.h\fR header file used to include it. The default if
2638undefined is \f(CW\*(C`<ev.h>\*(C'\fR in \fIevent.h\fR and \f(CW"ev.h"\fR in \fIev.c\fR. This 2708undefined is \f(CW"ev.h"\fR in \fIevent.h\fR and \fIev.c\fR. This can be used to
2639can be used to virtually rename the \fIev.h\fR header file in case of conflicts. 2709virtually rename the \fIev.h\fR header file in case of conflicts.
2640.IP "\s-1EV_CONFIG_H\s0" 4 2710.IP "\s-1EV_CONFIG_H\s0" 4
2641.IX Item "EV_CONFIG_H" 2711.IX Item "EV_CONFIG_H"
2642If \f(CW\*(C`EV_STANDALONE\*(C'\fR isn't \f(CW1\fR, this variable can be used to override 2712If \f(CW\*(C`EV_STANDALONE\*(C'\fR isn't \f(CW1\fR, this variable can be used to override
2643\&\fIev.c\fR's idea of where to find the \fIconfig.h\fR file, similarly to 2713\&\fIev.c\fR's idea of where to find the \fIconfig.h\fR file, similarly to
2644\&\f(CW\*(C`EV_H\*(C'\fR, above. 2714\&\f(CW\*(C`EV_H\*(C'\fR, above.
2645.IP "\s-1EV_EVENT_H\s0" 4 2715.IP "\s-1EV_EVENT_H\s0" 4
2646.IX Item "EV_EVENT_H" 2716.IX Item "EV_EVENT_H"
2647Similarly to \f(CW\*(C`EV_H\*(C'\fR, this macro can be used to override \fIevent.c\fR's idea 2717Similarly to \f(CW\*(C`EV_H\*(C'\fR, this macro can be used to override \fIevent.c\fR's idea
2648of how the \fIevent.h\fR header can be found. 2718of how the \fIevent.h\fR header can be found, the dfeault is \f(CW"event.h"\fR.
2649.IP "\s-1EV_PROTOTYPES\s0" 4 2719.IP "\s-1EV_PROTOTYPES\s0" 4
2650.IX Item "EV_PROTOTYPES" 2720.IX Item "EV_PROTOTYPES"
2651If defined to be \f(CW0\fR, then \fIev.h\fR will not define any function 2721If defined to be \f(CW0\fR, then \fIev.h\fR will not define any function
2652prototypes, but still define all the structs and other symbols. This is 2722prototypes, but still define all the structs and other symbols. This is
2653occasionally useful if you want to provide your own wrapper functions 2723occasionally useful if you want to provide your own wrapper functions
… …
2710pid. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), usually more 2780pid. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), usually more
2711than enough. If you need to manage thousands of children you might want to 2781than enough. If you need to manage thousands of children you might want to
2712increase this value (\fImust\fR be a power of two). 2782increase this value (\fImust\fR be a power of two).
2713.IP "\s-1EV_INOTIFY_HASHSIZE\s0" 4 2783.IP "\s-1EV_INOTIFY_HASHSIZE\s0" 4
2714.IX Item "EV_INOTIFY_HASHSIZE" 2784.IX Item "EV_INOTIFY_HASHSIZE"
2715\&\f(CW\*(C`ev_staz\*(C'\fR watchers use a small hash table to distribute workload by 2785\&\f(CW\*(C`ev_stat\*(C'\fR watchers use a small hash table to distribute workload by
2716inotify watch id. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), 2786inotify watch id. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR),
2717usually more than enough. If you need to manage thousands of \f(CW\*(C`ev_stat\*(C'\fR 2787usually more than enough. If you need to manage thousands of \f(CW\*(C`ev_stat\*(C'\fR
2718watchers you might want to increase this value (\fImust\fR be a power of 2788watchers you might want to increase this value (\fImust\fR be a power of
2719two). 2789two).
2720.IP "\s-1EV_COMMON\s0" 4 2790.IP "\s-1EV_COMMON\s0" 4
… …
2824.RS 4 2894.RS 4
2825.IP "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" 4 2895.IP "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" 4
2826.IX Item "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" 2896.IX Item "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)"
2827This means that, when you have a watcher that triggers in one hour and 2897This means that, when you have a watcher that triggers in one hour and
2828there are 100 watchers that would trigger before that then inserting will 2898there are 100 watchers that would trigger before that then inserting will
2829have to skip those 100 watchers. 2899have to skip roughly seven (\f(CW\*(C`ld 100\*(C'\fR) of these watchers.
2830.IP "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" 4 2900.IP "Changing timer/periodic watchers (by autorepeat or calling again): O(log skipped_other_timers)" 4
2831.IX Item "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" 2901.IX Item "Changing timer/periodic watchers (by autorepeat or calling again): O(log skipped_other_timers)"
2832That means that for changing a timer costs less than removing/adding them 2902That means that changing a timer costs less than removing/adding them
2833as only the relative motion in the event queue has to be paid for. 2903as only the relative motion in the event queue has to be paid for.
2834.IP "Starting io/check/prepare/idle/signal/child watchers: O(1)" 4 2904.IP "Starting io/check/prepare/idle/signal/child watchers: O(1)" 4
2835.IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)" 2905.IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)"
2836These just add the watcher into an array or at the head of a list. 2906These just add the watcher into an array or at the head of a list.
2907.IP "Stopping check/prepare/idle watchers: O(1)" 4
2837=item Stopping check/prepare/idle watchers: O(1) 2908.IX Item "Stopping check/prepare/idle watchers: O(1)"
2909.PD 0
2838.IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % \s-1EV_PID_HASHSIZE\s0))" 4 2910.IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % \s-1EV_PID_HASHSIZE\s0))" 4
2839.IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))" 2911.IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))"
2912.PD
2840These watchers are stored in lists then need to be walked to find the 2913These watchers are stored in lists then need to be walked to find the
2841correct watcher to remove. The lists are usually short (you don't usually 2914correct watcher to remove. The lists are usually short (you don't usually
2842have many watchers waiting for the same fd or signal). 2915have many watchers waiting for the same fd or signal).
2843.IP "Finding the next timer per loop iteration: O(1)" 4 2916.IP "Finding the next timer in each loop iteration: O(1)" 4
2844.IX Item "Finding the next timer per loop iteration: O(1)" 2917.IX Item "Finding the next timer in each loop iteration: O(1)"
2845.PD 0 2918By virtue of using a binary heap, the next timer is always found at the
2919beginning of the storage array.
2846.IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4 2920.IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4
2847.IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 2921.IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)"
2848.PD
2849A change means an I/O watcher gets started or stopped, which requires 2922A change means an I/O watcher gets started or stopped, which requires
2850libev to recalculate its status (and possibly tell the kernel). 2923libev to recalculate its status (and possibly tell the kernel, depending
2851.IP "Activating one watcher: O(1)" 4 2924on backend and wether \f(CW\*(C`ev_io_set\*(C'\fR was used).
2852.IX Item "Activating one watcher: O(1)" 2925.IP "Activating one watcher (putting it into the pending state): O(1)" 4
2926.IX Item "Activating one watcher (putting it into the pending state): O(1)"
2853.PD 0 2927.PD 0
2854.IP "Priority handling: O(number_of_priorities)" 4 2928.IP "Priority handling: O(number_of_priorities)" 4
2855.IX Item "Priority handling: O(number_of_priorities)" 2929.IX Item "Priority handling: O(number_of_priorities)"
2856.PD 2930.PD
2857Priorities are implemented by allocating some space for each 2931Priorities are implemented by allocating some space for each
2858priority. When doing priority-based operations, libev usually has to 2932priority. When doing priority-based operations, libev usually has to
2859linearly search all the priorities. 2933linearly search all the priorities, but starting/stopping and activating
2934watchers becomes O(1) w.r.t. prioritiy handling.
2860.RE 2935.RE
2861.RS 4 2936.RS 4
2862.SH "AUTHOR" 2937.SH "AUTHOR"
2863.IX Header "AUTHOR" 2938.IX Header "AUTHOR"
2864Marc Lehmann <libev@schmorp.de>. 2939Marc Lehmann <libev@schmorp.de>.

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