[ViewVC] Diff of: cvs/libev/ev.pod

Comparing libev/ev.pod (file contents):
Revision 1.459 by root, Wed Jan 22 01:50:42 2020 UTC vs.
Revision 1.467 by root, Sun Sep 13 22:17:02 2020 UTC

    - Queue all expired timers.
    - Queue all expired periodics.
    - Queue all idle watchers with priority higher than that of pending events.
    - Queue all check watchers.
    - Call all queued watchers in reverse order (i.e. check watchers first).
-     Signals and child watchers are implemented as I/O watchers, and will
+     Signals, async and child watchers are implemented as I/O watchers, and
-     be handled here by queueing them when their watcher gets executed.
+     will be handled here by queueing them when their watcher gets executed.
    - If ev_break has been called, or EVRUN_ONCE or EVRUN_NOWAIT
      were used, or there are no active watchers, goto FINISH, otherwise
      continue with step LOOP.
    FINISH:
    - Reset the ev_break status iff it was EVBREAK_ONE.
 with a watcher-specific start function (C<< ev_TYPE_start (loop, watcher
 *) >>), and you can stop watching for events at any time by calling the
 corresponding stop function (C<< ev_TYPE_stop (loop, watcher *) >>.
 As long as your watcher is active (has been started but not stopped) you
-must not touch the values stored in it. Most specifically you must never
+must not touch the values stored in it except when explicitly documented
-reinitialise it or call its C<ev_TYPE_set> macro.
+otherwise. Most specifically you must never reinitialise it or call its
+C<ev_TYPE_set> macro.
 Each and every callback receives the event loop pointer as first, the
 registered watcher structure as second, and a bitset of received events as
 third argument.
 =item bool ev_is_active (ev_TYPE *watcher)
 Returns a true value iff the watcher is active (i.e. it has been started
 and not yet been stopped). As long as a watcher is active you must not modify
-it.
+it unless documented otherwise.
 =item bool ev_is_pending (ev_TYPE *watcher)
 Returns a true value iff the watcher is pending, (i.e. it has outstanding
 events but its callback has not yet been invoked). As long as a watcher
 Most members are additionally marked with either I<[read-only]>, meaning
 that, while the watcher is active, you can look at the member and expect
 some sensible content, but you must not modify it (you can modify it while
 the watcher is stopped to your hearts content), or I<[read-write]>, which
-means you can expect it to have some sensible content while the watcher
+means you can expect it to have some sensible content while the watcher is
-is active, but you can also modify it. Modifying it may not do something
+active, but you can also modify it (within the same thread as the event
+loop, i.e. without creating data races). Modifying it may not do something
 sensible or take immediate effect (or do anything at all), but libev will
 not crash or malfunction in any way.
 In any case, the documentation for each member will explain what the
 effects are, and if there are any additional access restrictions.
 =item ev_io_init (ev_io *, callback, int fd, int events)
 =item ev_io_set (ev_io *, int fd, int events)
 Configures an C<ev_io> watcher. The C<fd> is the file descriptor to
-receive events for and C<events> is either C<EV_READ>, C<EV_WRITE> or
+receive events for and C<events> is either C<EV_READ>, C<EV_WRITE>, both
-C<EV_READ | EV_WRITE>, to express the desire to receive the given events.
+C<EV_READ | EV_WRITE> or C<0>, to express the desire to receive the given
+events.
+Note that setting the C<events> to C<0> and starting the watcher is
+supported, but not specially optimized - if your program sometimes happens
+to generate this combination this is fine, but if it is easy to avoid
+starting an io watcher watching for no events you should do so.
 =item ev_io_modify (ev_io *, int events)
-Similar to C<ev_io_set>, but only changes the event mask. Using this might
+Similar to C<ev_io_set>, but only changes the requested events. Using this
-be faster with some backends, as libev can assume that the C<fd> still
+might be faster with some backends, as libev can assume that the C<fd>
-refers to the same underlying file description, something it cannot do
+still refers to the same underlying file description, something it cannot
-when using C<ev_io_set>.
+do when using C<ev_io_set>.
 =item int fd [no-modify]
 The file descriptor being watched. While it can be read at any time, you
 must not modify this member even when the watcher is stopped - always use
 C<ev_io_set> for that.
 =item int events [no-modify]
-The set of events being watched, among other flags. This field is a
+The set of events the fd is being watched for, among other flags. Remember
-bit set - to test for C<EV_READ>, use C<< w->events & EV_READ >>, and
+that this is a bit set - to test for C<EV_READ>, use C<< w->events &
-similarly for C<EV_WRITE>.
+EV_READ >>, and similarly for C<EV_WRITE>.
 As with C<fd>, you must not modify this member even when the watcher is
 stopped, always use C<ev_io_set> or C<ev_io_modify> for that.
 =back
 event loop thread and an unspecified mechanism to wake up the main thread.
 First, you need to associate some data with the event loop:
    typedef struct {
-     mutex_t lock; /* global loop lock */
+     pthread_mutex_t lock; /* global loop lock */
+     pthread_t tid;
+     pthread_cond_t invoke_cv;
      ev_async async_w;
-     thread_t tid;
-     cond_t invoke_cv;
    } userdata;
    void prepare_loop (EV_P)
    {
       // for simplicity, we use a static userdata struct.
       static userdata u;
-      ev_async_init (&u->async_w, async_cb);
+      ev_async_init (&u.async_w, async_cb);
-      ev_async_start (EV_A_ &u->async_w);
+      ev_async_start (EV_A_ &u.async_w);
-      pthread_mutex_init (&u->lock, 0);
+      pthread_mutex_init (&u.lock, 0);
-      pthread_cond_init (&u->invoke_cv, 0);
+      pthread_cond_init (&u.invoke_cv, 0);
       // now associate this with the loop
-      ev_set_userdata (EV_A_ u);
+      ev_set_userdata (EV_A_ &u);
       ev_set_invoke_pending_cb (EV_A_ l_invoke);
       ev_set_loop_release_cb (EV_A_ l_release, l_acquire);
       // then create the thread running ev_run
-      pthread_create (&u->tid, 0, l_run, EV_A);
+      pthread_create (&u.tid, 0, l_run, EV_A);
    }
 The callback for the C<ev_async> watcher does nothing: the watcher is used
 solely to wake up the event loop so it takes notice of any new watchers
 that might have been added:
 gets automatically stopped and restarted when reconfiguring it with this
 method.
 For C<ev::embed> watchers this method is called C<set_embed>, to avoid
 clashing with the C<set (loop)> method.
+For C<ev::io> watchers there is an additional C<set> method that acepts a
+new event mask only, and internally calls C<ev_io_modfify>.
 =item w->start ()
 Starts the watcher. Note that there is no C<loop> argument, as the
 constructor already stores the event loop.

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Comparing libev/ev.pod (file contents): Revision 1.459 by root, Wed Jan 22 01:50:42 2020 UTC vs. Revision 1.467 by root, Sun Sep 13 22:17:02 2020 UTC

Diff Legend

Comparing libev/ev.pod (file contents):
Revision 1.459 by root, Wed Jan 22 01:50:42 2020 UTC vs.
Revision 1.467 by root, Sun Sep 13 22:17:02 2020 UTC