英文:
How do I access member variables from a repeating timer callback
问题
使用RPI Pico SDK，我有三个文件。
我想要使用回调函数并访问类的私有成员。
回调函数位于SDK中，我无法修改它。
我该如何做？
/////// test.h
bool main_loop_timer_callback(struct repeating_timer *t);
class MyClass {
private:
static int count;
struct repeating_timer main_loop_timer;
public:
MyClass();
friend bool main_loop_timer_callback(struct repeating_timer *t);
};
//////// test.cc
#include <iostream>
#include "pico/stdlib.h"
#include "test.h"
using namespace std;
bool main_loop_timer_callback(struct repeating_timer *t) {
MyClass::count++;
cout << "callback " << MyClass::count << endl;
return true;
}
MyClass::MyClass() {
add_repeating_timer_us(-50000,
main_loop_timer_callback,
NULL,
&main_loop_timer);
count = 0;
};
/////// test-main.cc
#include "pico/stdlib.h"
#include "test.h"
using namespace std;
int main() {
MyClass test;
stdio_init_all();
}
英文:
Using the RPI Pico SDK, I have three files.
I want to use a callback function and access private members of a class.
The callback function is in an SDK and I can not modify it.
How do I do this?
/////// test.h
bool main_loop_timer_callback(struct repeating_timer *t);
class MyClass {
private:
static int count;
struct repeating_timer main_loop_timer;
public:
MyClass();
friend bool main_loop_timer_callback(struct repeating_timer *t);
};
//////// test.cc
#include <iostream>
#include "pico/stdlib.h"
#include "test.h"
using namespace std;
bool main_loop_timer_callback(struct repeating_timer *t) {
MyClass::count++;
cout << "callback " << MyClass::count << endl;
return true;
}
MyClass::MyClass() {
add_repeating_timer_us(-50000,
main_loop_timer_callback,
NULL,
&main_loop_timer);
count = 0;
};
/////// test-main.cc
#include "pico/stdlib.h"
#include "test.h"
using namespace std;
int main() {
MyClass test;
stdio_init_all();
}
答案1
得分: 1
Pico Pico repeating_timer API 允许您在添加定时器时传递一个 user_data 参数（传递给 add_repeating_timer_us 的第三个参数）。
该值稍后将在传递到回调函数的 struct repeating_timer 的 user_data 成员中返回。
这可以是您想要的任何内容，例如在您的情况下，一个指向 MyClass 的指针，只要您将其转换为 void * 类型。
英文:
The Pi Pico repeating_timer API allows you to pass a user_data argument when adding a timer (the third parameter to add_repeating_timer_us).
This value is later returned in the user_data member of the struct repeating_timer passed to your callback.
This can be anything you want, e.g. in your case, a pointer to MyClass, so long as you cast it to and from void *.
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