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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
792 792
793Ref/unref can be used to add or remove a reference count on the event 793Ref/unref can be used to add or remove a reference count on the event
794loop: Every watcher keeps one reference, and as long as the reference 794loop: Every watcher keeps one reference, and as long as the reference
795count is nonzero, C<ev_loop> will not return on its own. 795count is nonzero, C<ev_loop> will not return on its own.
796 796
797If you have a watcher you never unregister that should not keep C<ev_loop> 797This is useful when you have a watcher that you never intend to
798from returning, call ev_unref() after starting, and ev_ref() before 798unregister, but that nevertheless should not keep C<ev_loop> from
799returning. In such a case, call C<ev_unref> after starting, and C<ev_ref>
799stopping it. 800before stopping it.
800 801
801As an example, libev itself uses this for its internal signal pipe: It 802As an example, libev itself uses this for its internal signal pipe: It
802is not visible to the libev user and should not keep C<ev_loop> from 803is not visible to the libev user and should not keep C<ev_loop> from
803exiting if no event watchers registered by it are active. It is also an 804exiting if no event watchers registered by it are active. It is also an
804excellent way to do this for generic recurring timers or from within 805excellent way to do this for generic recurring timers or from within
919 920
920While event loop modifications are allowed between invocations of 921While event loop modifications are allowed between invocations of
921C<release> and C<acquire> (that's their only purpose after all), no 922C<release> and C<acquire> (that's their only purpose after all), no
922modifications done will affect the event loop, i.e. adding watchers will 923modifications 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 924have 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 925waited. Use an C<ev_async> watcher to wake up C<ev_loop> when you want it
925to take note of any changes you made. 926to take note of any changes you made.
926 927
927In theory, threads executing C<ev_loop> will be async-cancel safe between 928In theory, threads executing C<ev_loop> will be async-cancel safe between
928invocations of C<release> and C<acquire>. 929invocations of C<release> and C<acquire>.
929 930
1126 1127
1127 ev_io w; 1128 ev_io w;
1128 ev_init (&w, my_cb); 1129 ev_init (&w, my_cb);
1129 ev_io_set (&w, STDIN_FILENO, EV_READ); 1130 ev_io_set (&w, STDIN_FILENO, EV_READ);
1130 1131
1131=item C<ev_TYPE_set> (ev_TYPE *, [args]) 1132=item C<ev_TYPE_set> (ev_TYPE *watcher, [args])
1132 1133
1133This macro initialises the type-specific parts of a watcher. You need to 1134This 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 1135call 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 1136call 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 1137macro on a watcher that is active (it can be pending, however, which is a
1149 1150
1150Example: Initialise and set an C<ev_io> watcher in one step. 1151Example: Initialise and set an C<ev_io> watcher in one step.
1151 1152
1152 ev_io_init (&w, my_cb, STDIN_FILENO, EV_READ); 1153 ev_io_init (&w, my_cb, STDIN_FILENO, EV_READ);
1153 1154
1154=item C<ev_TYPE_start> (loop *, ev_TYPE *watcher) 1155=item C<ev_TYPE_start> (loop, ev_TYPE *watcher)
1155 1156
1156Starts (activates) the given watcher. Only active watchers will receive 1157Starts (activates) the given watcher. Only active watchers will receive
1157events. If the watcher is already active nothing will happen. 1158events. If the watcher is already active nothing will happen.
1158 1159
1159Example: Start the C<ev_io> watcher that is being abused as example in this 1160Example: Start the C<ev_io> watcher that is being abused as example in this
1160whole section. 1161whole section.
1161 1162
1162 ev_io_start (EV_DEFAULT_UC, &w); 1163 ev_io_start (EV_DEFAULT_UC, &w);
1163 1164
1164=item C<ev_TYPE_stop> (loop *, ev_TYPE *watcher) 1165=item C<ev_TYPE_stop> (loop, ev_TYPE *watcher)
1165 1166
1166Stops the given watcher if active, and clears the pending status (whether 1167Stops the given watcher if active, and clears the pending status (whether
1167the watcher was active or not). 1168the watcher was active or not).
1168 1169
1169It is possible that stopped watchers are pending - for example, 1170It is possible that stopped watchers are pending - for example,
1194=item ev_cb_set (ev_TYPE *watcher, callback) 1195=item ev_cb_set (ev_TYPE *watcher, callback)
1195 1196
1196Change the callback. You can change the callback at virtually any time 1197Change the callback. You can change the callback at virtually any time
1197(modulo threads). 1198(modulo threads).
1198 1199
1199=item ev_set_priority (ev_TYPE *watcher, priority) 1200=item ev_set_priority (ev_TYPE *watcher, int priority)
1200 1201
1201=item int ev_priority (ev_TYPE *watcher) 1202=item int ev_priority (ev_TYPE *watcher)
1202 1203
1203Set and query the priority of the watcher. The priority is a small 1204Set and query the priority of the watcher. The priority is a small
1204integer between C<EV_MAXPRI> (default: C<2>) and C<EV_MINPRI> 1205integer between C<EV_MAXPRI> (default: C<2>) and C<EV_MINPRI>
1236watcher isn't pending it does nothing and returns C<0>. 1237watcher isn't pending it does nothing and returns C<0>.
1237 1238
1238Sometimes it can be useful to "poll" a watcher instead of waiting for its 1239Sometimes it can be useful to "poll" a watcher instead of waiting for its
1239callback to be invoked, which can be accomplished with this function. 1240callback to be invoked, which can be accomplished with this function.
1240 1241
1241=item ev_feed_event (struct ev_loop *, watcher *, int revents) 1242=item ev_feed_event (loop, ev_TYPE *watcher, int revents)
1242 1243
1243Feeds the given event set into the event loop, as if the specified event 1244Feeds 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 1245had happened for the specified watcher (which must be a pointer to an
1245initialised but not necessarily started event watcher). Obviously you must 1246initialised but not necessarily started event watcher). Obviously you must
1246not free the watcher as long as it has pending events. 1247not free the watcher as long as it has pending events.
1854C<repeat> value), or reset the running timer to the C<repeat> value. 1855C<repeat> value), or reset the running timer to the C<repeat> value.
1855 1856
1856This sounds a bit complicated, see L<Be smart about timeouts>, above, for a 1857This sounds a bit complicated, see L<Be smart about timeouts>, above, for a
1857usage example. 1858usage example.
1858 1859
1859=item ev_timer_remaining (loop, ev_timer *) 1860=item ev_tstamp ev_timer_remaining (loop, ev_timer *)
1860 1861
1861Returns the remaining time until a timer fires. If the timer is active, 1862Returns the remaining time until a timer fires. If the timer is active,
1862then this time is relative to the current event loop time, otherwise it's 1863then this time is relative to the current event loop time, otherwise it's
1863the timeout value currently configured. 1864the timeout value currently configured.
1864 1865
2981=head3 Queueing 2982=head3 Queueing
2982 2983
2983C<ev_async> does not support queueing of data in any way. The reason 2984C<ev_async> does not support queueing of data in any way. The reason
2984is that the author does not know of a simple (or any) algorithm for a 2985is that the author does not know of a simple (or any) algorithm for a
2985multiple-writer-single-reader queue that works in all cases and doesn't 2986multiple-writer-single-reader queue that works in all cases and doesn't
2986need elaborate support such as pthreads. 2987need elaborate support such as pthreads or unportable memory access
2988semantics.
2987 2989
2988That means that if you want to queue data, you have to provide your own 2990That means that if you want to queue data, you have to provide your own
2989queue. But at least I can tell you how to implement locking around your 2991queue. But at least I can tell you how to implement locking around your
2990queue: 2992queue:
2991 2993
3149 /* doh, nothing entered */; 3151 /* doh, nothing entered */;
3150 } 3152 }
3151 3153
3152 ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0); 3154 ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0);
3153 3155
3154=item ev_feed_fd_event (struct ev_loop *, int fd, int revents) 3156=item ev_feed_fd_event (loop, int fd, int revents)
3155 3157
3156Feed an event on the given fd, as if a file descriptor backend detected 3158Feed an event on the given fd, as if a file descriptor backend detected
3157the given events it. 3159the given events it.
3158 3160
3159=item ev_feed_signal_event (struct ev_loop *loop, int signum) 3161=item ev_feed_signal_event (loop, int signum)
3160 3162
3161Feed an event as if the given signal occurred (C<loop> must be the default 3163Feed an event as if the given signal occurred (C<loop> must be the default
3162loop!). 3164loop!).
3163 3165
3164=back 3166=back
3244 3246
3245=over 4 3247=over 4
3246 3248
3247=item ev::TYPE::TYPE () 3249=item ev::TYPE::TYPE ()
3248 3250
3249=item ev::TYPE::TYPE (struct ev_loop *) 3251=item ev::TYPE::TYPE (loop)
3250 3252
3251=item ev::TYPE::~TYPE 3253=item ev::TYPE::~TYPE
3252 3254
3253The constructor (optionally) takes an event loop to associate the watcher 3255The constructor (optionally) takes an event loop to associate the watcher
3254with. If it is omitted, it will use C<EV_DEFAULT>. 3256with. If it is omitted, it will use C<EV_DEFAULT>.
3331Example: Use a plain function as callback. 3333Example: Use a plain function as callback.
3332 3334
3333 static void io_cb (ev::io &w, int revents) { } 3335 static void io_cb (ev::io &w, int revents) { }
3334 iow.set <io_cb> (); 3336 iow.set <io_cb> ();
3335 3337
3336=item w->set (struct ev_loop *) 3338=item w->set (loop)
3337 3339
3338Associates a different C<struct ev_loop> with this watcher. You can only 3340Associates a different C<struct ev_loop> with this watcher. You can only
3339do this when the watcher is inactive (and not pending either). 3341do this when the watcher is inactive (and not pending either).
3340 3342
3341=item w->set ([arguments]) 3343=item w->set ([arguments])

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