… | |
… | |
862 | |
862 | |
863 | This call will simply invoke all pending watchers while resetting their |
863 | This call will simply invoke all pending watchers while resetting their |
864 | pending state. Normally, C<ev_loop> does this automatically when required, |
864 | pending state. Normally, C<ev_loop> does this automatically when required, |
865 | but when overriding the invoke callback this call comes handy. |
865 | but when overriding the invoke callback this call comes handy. |
866 | |
866 | |
|
|
867 | =item int ev_pending_count (loop) |
|
|
868 | |
|
|
869 | Returns the number of pending watchers - zero indicates that no watchers |
|
|
870 | are pending. |
|
|
871 | |
867 | =item ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(EV_P)) |
872 | =item ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(EV_P)) |
868 | |
873 | |
869 | This overrides the invoke pending functionality of the loop: Instead of |
874 | This overrides the invoke pending functionality of the loop: Instead of |
870 | invoking all pending watchers when there are any, C<ev_loop> will call |
875 | invoking all pending watchers when there are any, C<ev_loop> will call |
871 | this callback instead. This is useful, for example, when you want to |
876 | this callback instead. This is useful, for example, when you want to |
… | |
… | |
3998 | protecting the loop data, respectively. |
4003 | protecting the loop data, respectively. |
3999 | |
4004 | |
4000 | static void |
4005 | static void |
4001 | l_release (EV_P) |
4006 | l_release (EV_P) |
4002 | { |
4007 | { |
4003 | udat *u = ev_userdata (EV_A); |
4008 | userdata *u = ev_userdata (EV_A); |
4004 | pthread_mutex_unlock (&u->lock); |
4009 | pthread_mutex_unlock (&u->lock); |
4005 | } |
4010 | } |
4006 | |
4011 | |
4007 | static void |
4012 | static void |
4008 | l_acquire (EV_P) |
4013 | l_acquire (EV_P) |
4009 | { |
4014 | { |
4010 | udat *u = ev_userdata (EV_A); |
4015 | userdata *u = ev_userdata (EV_A); |
4011 | pthread_mutex_lock (&u->lock); |
4016 | pthread_mutex_lock (&u->lock); |
4012 | } |
4017 | } |
4013 | |
4018 | |
4014 | The event loop thread first acquires the mutex, and then jumps straight |
4019 | The event loop thread first acquires the mutex, and then jumps straight |
4015 | into C<ev_loop>: |
4020 | into C<ev_loop>: |
… | |
… | |
4028 | } |
4033 | } |
4029 | |
4034 | |
4030 | Instead of invoking all pending watchers, the C<l_invoke> callback will |
4035 | Instead of invoking all pending watchers, the C<l_invoke> callback will |
4031 | signal the main thread via some unspecified mechanism (signals? pipe |
4036 | signal the main thread via some unspecified mechanism (signals? pipe |
4032 | writes? C<Async::Interrupt>?) and then waits until all pending watchers |
4037 | writes? C<Async::Interrupt>?) and then waits until all pending watchers |
4033 | have been called: |
4038 | have been called (in a while loop because a) spurious wakeups are possible |
|
|
4039 | and b) skipping inter-thread-communication when there are no pending |
|
|
4040 | watchers is very beneficial): |
4034 | |
4041 | |
4035 | static void |
4042 | static void |
4036 | l_invoke (EV_P) |
4043 | l_invoke (EV_P) |
4037 | { |
4044 | { |
4038 | udat *u = ev_userdata (EV_A); |
4045 | userdata *u = ev_userdata (EV_A); |
4039 | |
4046 | |
|
|
4047 | while (ev_pending_count (EV_A)) |
|
|
4048 | { |
4040 | wake_up_other_thread_in_some_magic_or_not_so_magic_way (); |
4049 | wake_up_other_thread_in_some_magic_or_not_so_magic_way (); |
4041 | |
|
|
4042 | pthread_cond_wait (&u->invoke_cv, &u->lock); |
4050 | pthread_cond_wait (&u->invoke_cv, &u->lock); |
|
|
4051 | } |
4043 | } |
4052 | } |
4044 | |
4053 | |
4045 | Now, whenever the main thread gets told to invoke pending watchers, it |
4054 | Now, whenever the main thread gets told to invoke pending watchers, it |
4046 | will grab the lock, call C<ev_invoke_pending> and then signal the loop |
4055 | will grab the lock, call C<ev_invoke_pending> and then signal the loop |
4047 | thread to continue: |
4056 | thread to continue: |
4048 | |
4057 | |
4049 | static void |
4058 | static void |
4050 | real_invoke_pending (EV_P) |
4059 | real_invoke_pending (EV_P) |
4051 | { |
4060 | { |
4052 | udat *u = ev_userdata (EV_A); |
4061 | userdata *u = ev_userdata (EV_A); |
4053 | |
4062 | |
4054 | pthread_mutex_lock (&u->lock); |
4063 | pthread_mutex_lock (&u->lock); |
4055 | ev_invoke_pending (EV_A); |
4064 | ev_invoke_pending (EV_A); |
4056 | pthread_cond_signal (&u->invoke_cv); |
4065 | pthread_cond_signal (&u->invoke_cv); |
4057 | pthread_mutex_unlock (&u->lock); |
4066 | pthread_mutex_unlock (&u->lock); |
… | |
… | |
4059 | |
4068 | |
4060 | Whenever you want to start/stop a watcher or do other modifications to an |
4069 | Whenever you want to start/stop a watcher or do other modifications to an |
4061 | event loop, you will now have to lock: |
4070 | event loop, you will now have to lock: |
4062 | |
4071 | |
4063 | ev_timer timeout_watcher; |
4072 | ev_timer timeout_watcher; |
4064 | udat *u = ev_userdata (EV_A); |
4073 | userdata *u = ev_userdata (EV_A); |
4065 | |
4074 | |
4066 | ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.); |
4075 | ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.); |
4067 | |
4076 | |
4068 | pthread_mutex_lock (&u->lock); |
4077 | pthread_mutex_lock (&u->lock); |
4069 | ev_timer_start (EV_A_ &timeout_watcher); |
4078 | ev_timer_start (EV_A_ &timeout_watcher); |
… | |
… | |
4078 | =head3 COROUTINES |
4087 | =head3 COROUTINES |
4079 | |
4088 | |
4080 | Libev is very accommodating to coroutines ("cooperative threads"): |
4089 | Libev is very accommodating to coroutines ("cooperative threads"): |
4081 | libev fully supports nesting calls to its functions from different |
4090 | libev fully supports nesting calls to its functions from different |
4082 | coroutines (e.g. you can call C<ev_loop> on the same loop from two |
4091 | coroutines (e.g. you can call C<ev_loop> on the same loop from two |
4083 | different coroutines, and switch freely between both coroutines running the |
4092 | different coroutines, and switch freely between both coroutines running |
4084 | loop, as long as you don't confuse yourself). The only exception is that |
4093 | the loop, as long as you don't confuse yourself). The only exception is |
4085 | you must not do this from C<ev_periodic> reschedule callbacks. |
4094 | that you must not do this from C<ev_periodic> reschedule callbacks. |
4086 | |
4095 | |
4087 | Care has been taken to ensure that libev does not keep local state inside |
4096 | Care has been taken to ensure that libev does not keep local state inside |
4088 | C<ev_loop>, and other calls do not usually allow for coroutine switches as |
4097 | C<ev_loop>, and other calls do not usually allow for coroutine switches as |
4089 | they do not call any callbacks. |
4098 | they do not call any callbacks. |
4090 | |
4099 | |