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

Comparing libev/ev.pod (file contents):
Revision 1.272 by root, Tue Nov 24 06:39:28 2009 UTC vs.
Revision 1.275 by root, Sat Dec 26 09:21:54 2009 UTC

118Libev is very configurable. In this manual the default (and most common) 118Libev is very configurable. In this manual the default (and most common)
119configuration will be described, which supports multiple event loops. For 119configuration will be described, which supports multiple event loops. For
120more info about various configuration options please have a look at 120more info about various configuration options please have a look at
121B<EMBED> section in this manual. If libev was configured without support 121B<EMBED> section in this manual. If libev was configured without support
122for multiple event loops, then all functions taking an initial argument of 122for multiple event loops, then all functions taking an initial argument of
123name C<loop> (which is always of type C<ev_loop *>) will not have 123name C<loop> (which is always of type C<struct ev_loop *>) will not have
124this argument. 124this argument.
125 125
126=head2 TIME REPRESENTATION 126=head2 TIME REPRESENTATION
127 127
128Libev represents time as a single floating point number, representing 128Libev represents time as a single floating point number, representing
919 919
920While event loop modifications are allowed between invocations of 920While event loop modifications are allowed between invocations of
921C<release> and C<acquire> (that's their only purpose after all), no 921C<release> and C<acquire> (that's their only purpose after all), no
922modifications done will affect the event loop, i.e. adding watchers will 922modifications done will affect the event loop, i.e. adding watchers will
923have no effect on the set of file descriptors being watched, or the time 923have no effect on the set of file descriptors being watched, or the time
924waited. USe an C<ev_async> watcher to wake up C<ev_loop> when you want it 924waited. Use an C<ev_async> watcher to wake up C<ev_loop> when you want it
925to take note of any changes you made. 925to take note of any changes you made.
926 926
927In theory, threads executing C<ev_loop> will be async-cancel safe between 927In theory, threads executing C<ev_loop> will be async-cancel safe between
928invocations of C<release> and C<acquire>. 928invocations of C<release> and C<acquire>.
929 929
1126 1126
1127 ev_io w; 1127 ev_io w;
1128 ev_init (&w, my_cb); 1128 ev_init (&w, my_cb);
1129 ev_io_set (&w, STDIN_FILENO, EV_READ); 1129 ev_io_set (&w, STDIN_FILENO, EV_READ);
1130 1130
1131=item C<ev_TYPE_set> (ev_TYPE *, [args]) 1131=item C<ev_TYPE_set> (ev_TYPE *watcher, [args])
1132 1132
1133This macro initialises the type-specific parts of a watcher. You need to 1133This macro initialises the type-specific parts of a watcher. You need to
1134call C<ev_init> at least once before you call this macro, but you can 1134call C<ev_init> at least once before you call this macro, but you can
1135call C<ev_TYPE_set> any number of times. You must not, however, call this 1135call C<ev_TYPE_set> any number of times. You must not, however, call this
1136macro on a watcher that is active (it can be pending, however, which is a 1136macro on a watcher that is active (it can be pending, however, which is a
1149 1149
1150Example: Initialise and set an C<ev_io> watcher in one step. 1150Example: Initialise and set an C<ev_io> watcher in one step.
1151 1151
1152 ev_io_init (&w, my_cb, STDIN_FILENO, EV_READ); 1152 ev_io_init (&w, my_cb, STDIN_FILENO, EV_READ);
1153 1153
1154=item C<ev_TYPE_start> (loop *, ev_TYPE *watcher) 1154=item C<ev_TYPE_start> (loop, ev_TYPE *watcher)
1155 1155
1156Starts (activates) the given watcher. Only active watchers will receive 1156Starts (activates) the given watcher. Only active watchers will receive
1157events. If the watcher is already active nothing will happen. 1157events. If the watcher is already active nothing will happen.
1158 1158
1159Example: Start the C<ev_io> watcher that is being abused as example in this 1159Example: Start the C<ev_io> watcher that is being abused as example in this
1160whole section. 1160whole section.
1161 1161
1162 ev_io_start (EV_DEFAULT_UC, &w); 1162 ev_io_start (EV_DEFAULT_UC, &w);
1163 1163
1164=item C<ev_TYPE_stop> (loop *, ev_TYPE *watcher) 1164=item C<ev_TYPE_stop> (loop, ev_TYPE *watcher)
1165 1165
1166Stops the given watcher if active, and clears the pending status (whether 1166Stops the given watcher if active, and clears the pending status (whether
1167the watcher was active or not). 1167the watcher was active or not).
1168 1168
1169It is possible that stopped watchers are pending - for example, 1169It is possible that stopped watchers are pending - for example,
1194=item ev_cb_set (ev_TYPE *watcher, callback) 1194=item ev_cb_set (ev_TYPE *watcher, callback)
1195 1195
1196Change the callback. You can change the callback at virtually any time 1196Change the callback. You can change the callback at virtually any time
1197(modulo threads). 1197(modulo threads).
1198 1198
1199=item ev_set_priority (ev_TYPE *watcher, priority) 1199=item ev_set_priority (ev_TYPE *watcher, int priority)
1200 1200
1201=item int ev_priority (ev_TYPE *watcher) 1201=item int ev_priority (ev_TYPE *watcher)
1202 1202
1203Set and query the priority of the watcher. The priority is a small 1203Set and query the priority of the watcher. The priority is a small
1204integer between C<EV_MAXPRI> (default: C<2>) and C<EV_MINPRI> 1204integer between C<EV_MAXPRI> (default: C<2>) and C<EV_MINPRI>
1235returns its C<revents> bitset (as if its callback was invoked). If the 1235returns its C<revents> bitset (as if its callback was invoked). If the
1236watcher isn't pending it does nothing and returns C<0>. 1236watcher isn't pending it does nothing and returns C<0>.
1237 1237
1238Sometimes it can be useful to "poll" a watcher instead of waiting for its 1238Sometimes it can be useful to "poll" a watcher instead of waiting for its
1239callback to be invoked, which can be accomplished with this function. 1239callback to be invoked, which can be accomplished with this function.
1240
1241=item ev_feed_event (loop, ev_TYPE *watcher, int revents)
1242
1243Feeds the given event set into the event loop, as if the specified event
1244had happened for the specified watcher (which must be a pointer to an
1245initialised but not necessarily started event watcher). Obviously you must
1246not free the watcher as long as it has pending events.
1247
1248Stopping the watcher, letting libev invoke it, or calling
1249C<ev_clear_pending> will clear the pending event, even if the watcher was
1250not started in the first place.
1251
1252See also C<ev_feed_fd_event> and C<ev_feed_signal_event> for related
1253functions that do not need a watcher.
1240 1254
1241=back 1255=back
1242 1256
1243 1257
1244=head2 ASSOCIATING CUSTOM DATA WITH A WATCHER 1258=head2 ASSOCIATING CUSTOM DATA WITH A WATCHER
1840C<repeat> value), or reset the running timer to the C<repeat> value. 1854C<repeat> value), or reset the running timer to the C<repeat> value.
1841 1855
1842This sounds a bit complicated, see L<Be smart about timeouts>, above, for a 1856This sounds a bit complicated, see L<Be smart about timeouts>, above, for a
1843usage example. 1857usage example.
1844 1858
1845=item ev_timer_remaining (loop, ev_timer *) 1859=item ev_tstamp ev_timer_remaining (loop, ev_timer *)
1846 1860
1847Returns the remaining time until a timer fires. If the timer is active, 1861Returns the remaining time until a timer fires. If the timer is active,
1848then this time is relative to the current event loop time, otherwise it's 1862then this time is relative to the current event loop time, otherwise it's
1849the timeout value currently configured. 1863the timeout value currently configured.
1850 1864
2967=head3 Queueing 2981=head3 Queueing
2968 2982
2969C<ev_async> does not support queueing of data in any way. The reason 2983C<ev_async> does not support queueing of data in any way. The reason
2970is that the author does not know of a simple (or any) algorithm for a 2984is that the author does not know of a simple (or any) algorithm for a
2971multiple-writer-single-reader queue that works in all cases and doesn't 2985multiple-writer-single-reader queue that works in all cases and doesn't
2972need elaborate support such as pthreads. 2986need elaborate support such as pthreads or unportable memory access
2987semantics.
2973 2988
2974That means that if you want to queue data, you have to provide your own 2989That means that if you want to queue data, you have to provide your own
2975queue. But at least I can tell you how to implement locking around your 2990queue. But at least I can tell you how to implement locking around your
2976queue: 2991queue:
2977 2992
3135 /* doh, nothing entered */; 3150 /* doh, nothing entered */;
3136 } 3151 }
3137 3152
3138 ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0); 3153 ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0);
3139 3154
3140=item ev_feed_event (struct ev_loop *, watcher *, int revents)
3141
3142Feeds the given event set into the event loop, as if the specified event
3143had happened for the specified watcher (which must be a pointer to an
3144initialised but not necessarily started event watcher).
3145
3146=item ev_feed_fd_event (struct ev_loop *, int fd, int revents) 3155=item ev_feed_fd_event (loop, int fd, int revents)
3147 3156
3148Feed an event on the given fd, as if a file descriptor backend detected 3157Feed an event on the given fd, as if a file descriptor backend detected
3149the given events it. 3158the given events it.
3150 3159
3151=item ev_feed_signal_event (struct ev_loop *loop, int signum) 3160=item ev_feed_signal_event (loop, int signum)
3152 3161
3153Feed an event as if the given signal occurred (C<loop> must be the default 3162Feed an event as if the given signal occurred (C<loop> must be the default
3154loop!). 3163loop!).
3155 3164
3156=back 3165=back
3236 3245
3237=over 4 3246=over 4
3238 3247
3239=item ev::TYPE::TYPE () 3248=item ev::TYPE::TYPE ()
3240 3249
3241=item ev::TYPE::TYPE (struct ev_loop *) 3250=item ev::TYPE::TYPE (loop)
3242 3251
3243=item ev::TYPE::~TYPE 3252=item ev::TYPE::~TYPE
3244 3253
3245The constructor (optionally) takes an event loop to associate the watcher 3254The constructor (optionally) takes an event loop to associate the watcher
3246with. If it is omitted, it will use C<EV_DEFAULT>. 3255with. If it is omitted, it will use C<EV_DEFAULT>.
3323Example: Use a plain function as callback. 3332Example: Use a plain function as callback.
3324 3333
3325 static void io_cb (ev::io &w, int revents) { } 3334 static void io_cb (ev::io &w, int revents) { }
3326 iow.set <io_cb> (); 3335 iow.set <io_cb> ();
3327 3336
3328=item w->set (struct ev_loop *) 3337=item w->set (loop)
3329 3338
3330Associates a different C<struct ev_loop> with this watcher. You can only 3339Associates a different C<struct ev_loop> with this watcher. You can only
3331do this when the watcher is inactive (and not pending either). 3340do this when the watcher is inactive (and not pending either).
3332 3341
3333=item w->set ([arguments]) 3342=item w->set ([arguments])

Diff Legend

Removed lines
+ Added lines
< Changed lines
> Changed lines