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Comparing libev/ev.pod (file contents):
Revision 1.55 by root, Tue Nov 27 20:38:07 2007 UTC vs.
Revision 1.57 by root, Wed Nov 28 11:27:29 2007 UTC

… …
1222not exist" is signified by the C<st_nlink> field being zero (which is 1222not exist" is signified by the C<st_nlink> field being zero (which is
1223otherwise always forced to be at least one) and all the other fields of 1223otherwise always forced to be at least one) and all the other fields of
1224the stat buffer having unspecified contents. 1224the stat buffer having unspecified contents.
1225 1225
1226Since there is no standard to do this, the portable implementation simply 1226Since there is no standard to do this, the portable implementation simply
1227calls C<stat (2)> regulalry on the path to see if it changed somehow. You 1227calls C<stat (2)> regularly on the path to see if it changed somehow. You
1228can specify a recommended polling interval for this case. If you specify 1228can specify a recommended polling interval for this case. If you specify
1229a polling interval of C<0> (highly recommended!) then a I<suitable, 1229a polling interval of C<0> (highly recommended!) then a I<suitable,
1230unspecified default> value will be used (which you can expect to be around 1230unspecified default> value will be used (which you can expect to be around
1231five seconds, although this might change dynamically). Libev will also 1231five seconds, although this might change dynamically). Libev will also
1232impose a minimum interval which is currently around C<0.1>, but thats 1232impose a minimum interval which is currently around C<0.1>, but thats
… …
1234 1234
1235This watcher type is not meant for massive numbers of stat watchers, 1235This watcher type is not meant for massive numbers of stat watchers,
1236as even with OS-supported change notifications, this can be 1236as even with OS-supported change notifications, this can be
1237resource-intensive. 1237resource-intensive.
1238 1238
1239At the time of this writing, no specific OS backends are implemented, but 1239At the time of this writing, only the Linux inotify interface is
1240if demand increases, at least a kqueue and inotify backend will be added. 1240implemented (implementing kqueue support is left as an exercise for the
1241reader). Inotify will be used to give hints only and should not change the
1242semantics of C<ev_stat> watchers, which means that libev sometimes needs
1243to fall back to regular polling again even with inotify, but changes are
1244usually detected immediately, and if the file exists there will be no
1245polling.
1241 1246
1242=over 4 1247=over 4
1243 1248
1244=item ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval) 1249=item ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)
1245 1250
… …
2014 2019
2015=item EV_USE_DEVPOLL 2020=item EV_USE_DEVPOLL
2016 2021
2017reserved for future expansion, works like the USE symbols above. 2022reserved for future expansion, works like the USE symbols above.
2018 2023
2024=item EV_USE_INOTIFY
2025
2026If defined to be C<1>, libev will compile in support for the Linux inotify
2027interface to speed up C<ev_stat> watchers. Its actual availability will
2028be detected at runtime.
2029
2019=item EV_H 2030=item EV_H
2020 2031
2021The name of the F<ev.h> header file used to include it. The default if 2032The name of the F<ev.h> header file used to include it. The default if
2022undefined is C<< <ev.h> >> in F<event.h> and C<"ev.h"> in F<ev.c>. This 2033undefined is C<< <ev.h> >> in F<event.h> and C<"ev.h"> in F<ev.c>. This
2023can be used to virtually rename the F<ev.h> header file in case of conflicts. 2034can be used to virtually rename the F<ev.h> header file in case of conflicts.
… …
2078=item EV_PID_HASHSIZE 2089=item EV_PID_HASHSIZE
2079 2090
2080C<ev_child> watchers use a small hash table to distribute workload by 2091C<ev_child> watchers use a small hash table to distribute workload by
2081pid. The default size is C<16> (or C<1> with C<EV_MINIMAL>), usually more 2092pid. The default size is C<16> (or C<1> with C<EV_MINIMAL>), usually more
2082than enough. If you need to manage thousands of children you might want to 2093than enough. If you need to manage thousands of children you might want to
2083increase this value. 2094increase this value (I<must> be a power of two).
2095
2096=item EV_INOTIFY_HASHSIZE
2097
2098C<ev_staz> watchers use a small hash table to distribute workload by
2099inotify watch id. The default size is C<16> (or C<1> with C<EV_MINIMAL>),
2100usually more than enough. If you need to manage thousands of C<ev_stat>
2101watchers you might want to increase this value (I<must> be a power of
2102two).
2084 2103
2085=item EV_COMMON 2104=item EV_COMMON
2086 2105
2087By default, all watchers have a C<void *data> member. By redefining 2106By default, all watchers have a C<void *data> member. By redefining
2088this macro to a something else you can include more and other types of 2107this macro to a something else you can include more and other types of
… …
2148 2167
2149=item Starting io/check/prepare/idle/signal/child watchers: O(1) 2168=item Starting io/check/prepare/idle/signal/child watchers: O(1)
2150 2169
2151=item Stopping check/prepare/idle watchers: O(1) 2170=item Stopping check/prepare/idle watchers: O(1)
2152 2171
2153=item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % 16)) 2172=item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))
2154 2173
2155=item Finding the next timer per loop iteration: O(1) 2174=item Finding the next timer per loop iteration: O(1)
2156 2175
2157=item Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd) 2176=item Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)
2158 2177

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