ViewVC Help
View File | Revision Log | Show Annotations | Download File
/cvs/libev/ev.3
(Generate patch)

Comparing libev/ev.3 (file contents):
Revision 1.28 by root, Tue Nov 27 20:26:50 2007 UTC vs.
Revision 1.30 by root, Wed Nov 28 11:27:29 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 "2007-11-27" "perl v5.8.8" "User Contributed Perl Documentation" 132.TH "<STANDARD INPUT>" 1 "2007-11-28" "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
… …
856Returns a true value iff the watcher is pending, (i.e. it has outstanding 856Returns a true value iff the watcher is pending, (i.e. it has outstanding
857events but its callback has not yet been invoked). As long as a watcher 857events but its callback has not yet been invoked). As long as a watcher
858is pending (but not active) you must not call an init function on it (but 858is pending (but not active) you must not call an init function on it (but
859\&\f(CW\*(C`ev_TYPE_set\*(C'\fR is safe) and you must make sure the watcher is available to 859\&\f(CW\*(C`ev_TYPE_set\*(C'\fR is safe) and you must make sure the watcher is available to
860libev (e.g. you cnanot \f(CW\*(C`free ()\*(C'\fR it). 860libev (e.g. you cnanot \f(CW\*(C`free ()\*(C'\fR it).
861.IP "callback = ev_cb (ev_TYPE *watcher)" 4 861.IP "callback ev_cb (ev_TYPE *watcher)" 4
862.IX Item "callback = ev_cb (ev_TYPE *watcher)" 862.IX Item "callback ev_cb (ev_TYPE *watcher)"
863Returns the callback currently set on the watcher. 863Returns the callback currently set on the watcher.
864.IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 864.IP "ev_cb_set (ev_TYPE *watcher, callback)" 4
865.IX Item "ev_cb_set (ev_TYPE *watcher, callback)" 865.IX Item "ev_cb_set (ev_TYPE *watcher, callback)"
866Change the callback. You can change the callback at virtually any time 866Change the callback. You can change the callback at virtually any time
867(modulo threads). 867(modulo threads).
… …
893\& struct my_io *w = (struct my_io *)w_; 893\& struct my_io *w = (struct my_io *)w_;
894\& ... 894\& ...
895\& } 895\& }
896.Ve 896.Ve
897.PP 897.PP
898More interesting and less C\-conformant ways of catsing your callback type 898More interesting and less C\-conformant ways of casting your callback type
899have been omitted.... 899instead have been omitted.
900.PP
901Another common scenario is having some data structure with multiple
902watchers:
903.PP
904.Vb 6
905\& struct my_biggy
906\& {
907\& int some_data;
908\& ev_timer t1;
909\& ev_timer t2;
910\& }
911.Ve
912.PP
913In this case getting the pointer to \f(CW\*(C`my_biggy\*(C'\fR is a bit more complicated,
914you need to use \f(CW\*(C`offsetof\*(C'\fR:
915.PP
916.Vb 1
917\& #include <stddef.h>
918.Ve
919.PP
920.Vb 6
921\& static void
922\& t1_cb (EV_P_ struct ev_timer *w, int revents)
923\& {
924\& struct my_biggy big = (struct my_biggy *
925\& (((char *)w) - offsetof (struct my_biggy, t1));
926\& }
927.Ve
928.PP
929.Vb 6
930\& static void
931\& t2_cb (EV_P_ struct ev_timer *w, int revents)
932\& {
933\& struct my_biggy big = (struct my_biggy *
934\& (((char *)w) - offsetof (struct my_biggy, t2));
935\& }
936.Ve
900.SH "WATCHER TYPES" 937.SH "WATCHER TYPES"
901.IX Header "WATCHER TYPES" 938.IX Header "WATCHER TYPES"
902This section describes each watcher in detail, but will not repeat 939This section describes each watcher in detail, but will not repeat
903information given in the last section. Any initialisation/set macros, 940information given in the last section. Any initialisation/set macros,
904functions and members specific to the watcher type are explained. 941functions and members specific to the watcher type are explained.
… …
1346not exist\*(R" is signified by the \f(CW\*(C`st_nlink\*(C'\fR field being zero (which is 1383not exist\*(R" is signified by the \f(CW\*(C`st_nlink\*(C'\fR field being zero (which is
1347otherwise always forced to be at least one) and all the other fields of 1384otherwise always forced to be at least one) and all the other fields of
1348the stat buffer having unspecified contents. 1385the stat buffer having unspecified contents.
1349.PP 1386.PP
1350Since there is no standard to do this, the portable implementation simply 1387Since there is no standard to do this, the portable implementation simply
1351calls \f(CW\*(C`stat (2)\*(C'\fR regulalry on the path to see if it changed somehow. You 1388calls \f(CW\*(C`stat (2)\*(C'\fR regularly on the path to see if it changed somehow. You
1352can specify a recommended polling interval for this case. If you specify 1389can specify a recommended polling interval for this case. If you specify
1353a polling interval of \f(CW0\fR (highly recommended!) then a \fIsuitable, 1390a polling interval of \f(CW0\fR (highly recommended!) then a \fIsuitable,
1354unspecified default\fR value will be used (which you can expect to be around 1391unspecified default\fR value will be used (which you can expect to be around
1355five seconds, although this might change dynamically). Libev will also 1392five seconds, although this might change dynamically). Libev will also
1356impose a minimum interval which is currently around \f(CW0.1\fR, but thats 1393impose a minimum interval which is currently around \f(CW0.1\fR, but thats
… …
1358.PP 1395.PP
1359This watcher type is not meant for massive numbers of stat watchers, 1396This watcher type is not meant for massive numbers of stat watchers,
1360as even with OS-supported change notifications, this can be 1397as even with OS-supported change notifications, this can be
1361resource\-intensive. 1398resource\-intensive.
1362.PP 1399.PP
1363At the time of this writing, no specific \s-1OS\s0 backends are implemented, but 1400At the time of this writing, only the Linux inotify interface is
1364if demand increases, at least a kqueue and inotify backend will be added. 1401implemented (implementing kqueue support is left as an exercise for the
1402reader). Inotify will be used to give hints only and should not change the
1403semantics of \f(CW\*(C`ev_stat\*(C'\fR watchers, which means that libev sometimes needs
1404to fall back to regular polling again even with inotify, but changes are
1405usually detected immediately, and if the file exists there will be no
1406polling.
1365.IP "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" 4 1407.IP "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" 4
1366.IX Item "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" 1408.IX Item "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)"
1367.PD 0 1409.PD 0
1368.IP "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" 4 1410.IP "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" 4
1369.IX Item "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" 1411.IX Item "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)"
… …
2133otherwise another method will be used as fallback. This is the preferred 2175otherwise another method will be used as fallback. This is the preferred
2134backend for Solaris 10 systems. 2176backend for Solaris 10 systems.
2135.IP "\s-1EV_USE_DEVPOLL\s0" 4 2177.IP "\s-1EV_USE_DEVPOLL\s0" 4
2136.IX Item "EV_USE_DEVPOLL" 2178.IX Item "EV_USE_DEVPOLL"
2137reserved for future expansion, works like the \s-1USE\s0 symbols above. 2179reserved for future expansion, works like the \s-1USE\s0 symbols above.
2180.IP "\s-1EV_USE_INOTIFY\s0" 4
2181.IX Item "EV_USE_INOTIFY"
2182If defined to be \f(CW1\fR, libev will compile in support for the Linux inotify
2183interface to speed up \f(CW\*(C`ev_stat\*(C'\fR watchers. Its actual availability will
2184be detected at runtime.
2138.IP "\s-1EV_H\s0" 4 2185.IP "\s-1EV_H\s0" 4
2139.IX Item "EV_H" 2186.IX Item "EV_H"
2140The name of the \fIev.h\fR header file used to include it. The default if 2187The name of the \fIev.h\fR header file used to include it. The default if
2141undefined is \f(CW\*(C`<ev.h>\*(C'\fR in \fIevent.h\fR and \f(CW"ev.h"\fR in \fIev.c\fR. This 2188undefined is \f(CW\*(C`<ev.h>\*(C'\fR in \fIevent.h\fR and \f(CW"ev.h"\fR in \fIev.c\fR. This
2142can be used to virtually rename the \fIev.h\fR header file in case of conflicts. 2189can be used to virtually rename the \fIev.h\fR header file in case of conflicts.
… …
2187.IP "\s-1EV_PID_HASHSIZE\s0" 4 2234.IP "\s-1EV_PID_HASHSIZE\s0" 4
2188.IX Item "EV_PID_HASHSIZE" 2235.IX Item "EV_PID_HASHSIZE"
2189\&\f(CW\*(C`ev_child\*(C'\fR watchers use a small hash table to distribute workload by 2236\&\f(CW\*(C`ev_child\*(C'\fR watchers use a small hash table to distribute workload by
2190pid. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), usually more 2237pid. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), usually more
2191than enough. If you need to manage thousands of children you might want to 2238than enough. If you need to manage thousands of children you might want to
2192increase this value. 2239increase this value (\fImust\fR be a power of two).
2240.IP "\s-1EV_INOTIFY_HASHSIZE\s0" 4
2241.IX Item "EV_INOTIFY_HASHSIZE"
2242\&\f(CW\*(C`ev_staz\*(C'\fR watchers use a small hash table to distribute workload by
2243inotify watch id. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR),
2244usually more than enough. If you need to manage thousands of \f(CW\*(C`ev_stat\*(C'\fR
2245watchers you might want to increase this value (\fImust\fR be a power of
2246two).
2193.IP "\s-1EV_COMMON\s0" 4 2247.IP "\s-1EV_COMMON\s0" 4
2194.IX Item "EV_COMMON" 2248.IX Item "EV_COMMON"
2195By default, all watchers have a \f(CW\*(C`void *data\*(C'\fR member. By redefining 2249By default, all watchers have a \f(CW\*(C`void *data\*(C'\fR member. By redefining
2196this macro to a something else you can include more and other types of 2250this macro to a something else you can include more and other types of
2197members. You have to define it each time you include one of the files, 2251members. You have to define it each time you include one of the files,
… …
2261.IX Item "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" 2315.IX Item "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)"
2262.IP "Starting io/check/prepare/idle/signal/child watchers: O(1)" 4 2316.IP "Starting io/check/prepare/idle/signal/child watchers: O(1)" 4
2263.IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)" 2317.IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)"
2264.IP "Stopping check/prepare/idle watchers: O(1)" 4 2318.IP "Stopping check/prepare/idle watchers: O(1)" 4
2265.IX Item "Stopping check/prepare/idle watchers: O(1)" 2319.IX Item "Stopping check/prepare/idle watchers: O(1)"
2266.IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % 16))" 4 2320.IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % \s-1EV_PID_HASHSIZE\s0))" 4
2267.IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % 16))" 2321.IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))"
2268.IP "Finding the next timer per loop iteration: O(1)" 4 2322.IP "Finding the next timer per loop iteration: O(1)" 4
2269.IX Item "Finding the next timer per loop iteration: O(1)" 2323.IX Item "Finding the next timer per loop iteration: O(1)"
2270.IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4 2324.IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4
2271.IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 2325.IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)"
2272.IP "Activating one watcher: O(1)" 4 2326.IP "Activating one watcher: O(1)" 4

Diff Legend

– Removed lines
+ Added lines
< Changed lines
> Changed lines