Event
The Event class provides APIs to configure events delay and period timings. The timings use the std::chrono::duration class provided by the <utility> library. You can use post API to post an event to the underlying EventQueue, and you can use cancel to cancel the most recently posted event.
The Event class is thread safe. The post and cancel APIs are IRQ safe.
Event class reference
| Public Member Functions | |
| template<typename F > | |
| Event (EventQueue *q, F f) | |
| Create an event. More... | |
| Event (const Event &e) | |
| Copy constructor for events. More... | |
| Event & | operator= (const Event &that) |
| Assignment operator for events. More... | |
| ~Event () | |
| Destructor for events. More... | |
| void | delay (duration d) |
| Configure the delay of an event. More... | |
| void | delay (int d) |
| Configure the delay of an event. More... | |
| void | period (duration p) |
| Configure the period of an event. More... | |
| void | period (int p) |
| Configure the period of an event. More... | |
| int | post (ArgTs...args) const |
| Posts an event onto the underlying event queue. More... | |
| void | call (ArgTs...args) const |
| Posts an event onto the underlying event queue, returning void. More... | |
| void | operator() (ArgTs...args) const |
| Posts an event onto the underlying event queue, returning void. More... | |
| void | cancel () const |
| Cancels the most recently posted event. More... | |
| template<typename F , typename... ContextArgTs> | |
| Event (EventQueue *q, F f, ContextArgTs...context_args) | |
| Create an event. More... | |
| template<typename T , typename R , typename B0 > | |
| Event (EventQueue *q, T *obj, R(T::*method)(B0, ArgTs...), B0 b0) | |
| Create an event. More... | |
| template<typename T , typename R , typename B0 > | |
| Event (EventQueue *q, const T *obj, R(T::*method)(B0, ArgTs...) const, B0 b0) | |
| Create an event. More... | |
| template<typename T , typename R , typename B0 > | |
| Event (EventQueue *q, volatile T *obj, R(T::*method)(B0, ArgTs...) volatile, B0 b0) | |
| Create an event. More... | |
| template<typename T , typename R , typename B0 > | |
| Event (EventQueue *q, const volatile T *obj, R(T::*method)(B0, ArgTs...) const volatile, B0 b0) | |
| Create an event. More... | |
| template<typename T , typename R , typename B0 , typename B1 > | |
| Event (EventQueue *q, T *obj, R(T::*method)(B0, B1, ArgTs...), B0 b0, B1 b1) | |
| Create an event. More... | |
| template<typename T , typename R , typename B0 , typename B1 > | |
| Event (EventQueue *q, const T *obj, R(T::*method)(B0, B1, ArgTs...) const, B0 b0, B1 b1) | |
| Create an event. More... | |
| template<typename T , typename R , typename B0 , typename B1 > | |
| Event (EventQueue *q, volatile T *obj, R(T::*method)(B0, B1, ArgTs...) volatile, B0 b0, B1 b1) | |
| Create an event. More... | |
| template<typename T , typename R , typename B0 , typename B1 > | |
| Event (EventQueue *q, const volatile T *obj, R(T::*method)(B0, B1, ArgTs...) const volatile, B0 b0, B1 b1) | |
| Create an event. More... | |
| template<typename T , typename R , typename B0 , typename B1 , typename B2 > | |
| Event (EventQueue *q, T *obj, R(T::*method)(B0, B1, B2, ArgTs...), B0 b0, B1 b1, B2 b2) | |
| Create an event. More... | |
| template<typename T , typename R , typename B0 , typename B1 , typename B2 > | |
| Event (EventQueue *q, const T *obj, R(T::*method)(B0, B1, B2, ArgTs...) const, B0 b0, B1 b1, B2 b2) | |
| Create an event. More... | |
| template<typename T , typename R , typename B0 , typename B1 , typename B2 > | |
| Event (EventQueue *q, volatile T *obj, R(T::*method)(B0, B1, B2, ArgTs...) volatile, B0 b0, B1 b1, B2 b2) | |
| Create an event. More... | |
| template<typename T , typename R , typename B0 , typename B1 , typename B2 > | |
| Event (EventQueue *q, const volatile T *obj, R(T::*method)(B0, B1, B2, ArgTs...) const volatile, B0 b0, B1 b1, B2 b2) | |
| Create an event. More... | |
| template<typename T , typename R , typename B0 , typename B1 , typename B2 , typename B3 > | |
| Event (EventQueue *q, T *obj, R(T::*method)(B0, B1, B2, B3, ArgTs...), B0 b0, B1 b1, B2 b2, B3 b3) | |
| Create an event. More... | |
| template<typename T , typename R , typename B0 , typename B1 , typename B2 , typename B3 > | |
| Event (EventQueue *q, const T *obj, R(T::*method)(B0, B1, B2, B3, ArgTs...) const, B0 b0, B1 b1, B2 b2, B3 b3) | |
| Create an event. More... | |
| template<typename T , typename R , typename B0 , typename B1 , typename B2 , typename B3 > | |
| Event (EventQueue *q, volatile T *obj, R(T::*method)(B0, B1, B2, B3, ArgTs...) volatile, B0 b0, B1 b1, B2 b2, B3 b3) | |
| Create an event. More... | |
| template<typename T , typename R , typename B0 , typename B1 , typename B2 , typename B3 > | |
| Event (EventQueue *q, const volatile T *obj, R(T::*method)(B0, B1, B2, B3, ArgTs...) const volatile, B0 b0, B1 b1, B2 b2, B3 b3) | |
| Create an event. More... | |
| template<typename T , typename R , typename B0 , typename B1 , typename B2 , typename B3 , typename B4 > | |
| Event (EventQueue *q, T *obj, R(T::*method)(B0, B1, B2, B3, B4, ArgTs...), B0 b0, B1 b1, B2 b2, B3 b3, B4 b4) | |
| Create an event. More... | |
| template<typename T , typename R , typename B0 , typename B1 , typename B2 , typename B3 , typename B4 > | |
| Event (EventQueue *q, const T *obj, R(T::*method)(B0, B1, B2, B3, B4, ArgTs...) const, B0 b0, B1 b1, B2 b2, B3 b3, B4 b4) | |
| Create an event. More... | |
| template<typename T , typename R , typename B0 , typename B1 , typename B2 , typename B3 , typename B4 > | |
| Event (EventQueue *q, volatile T *obj, R(T::*method)(B0, B1, B2, B3, B4, ArgTs...) volatile, B0 b0, B1 b1, B2 b2, B3 b3, B4 b4) | |
| Create an event. More... | |
| template<typename T , typename R , typename B0 , typename B1 , typename B2 , typename B3 , typename B4 > | |
| Event (EventQueue *q, const volatile T *obj, R(T::*method)(B0, B1, B2, B3, B4, ArgTs...) const volatile, B0 b0, B1 b1, B2 b2, B3 b3, B4 b4) | |
| Create an event. More... | |
| Static Public Member Functions | |
| static void | thunk (void *func, ArgTs...args) |
| Static thunk for passing as C-style function. More... | |
EventQueue example: posting events to the queue
The code below demonstrates how you can instantiate, configure and post events.
/*
* Copyright (c) 2020 Arm Limited and affiliates.
* SPDX-License-Identifier: Apache-2.0
*/
#include "mbed.h"
// Creates an event bound to the specified event queue
EventQueue queue;
void handler(int count);
Event<void(int)> event(&queue, handler);
void handler(int count)
{
printf("Event = %d \n", count);
return;
}
void post_events(void)
{
// Events can be posted multiple times and enqueue gracefully until
// the dispatch function is called.
event.post(1);
event.post(2);
event.post(3);
}
int main()
{
Thread event_thread;
// The event can be manually configured for special timing requirements
// specified in milliseconds
event.delay(100); // Starting delay - 100 msec
event.period(200); // Delay between each evet - 200msec
event_thread.start(callback(post_events));
// Posted events are dispatched in the context of the queue's
// dispatch function
queue.dispatch(400); // Dispatch time - 400msec
// 400 msec - Only 2 set of events will be dispatched as period is 200 msec
event_thread.join();
}