Question

我想将在“ CbSetter”类构造函数中定义的回调传递给“ CbReceptor”类构造函数，以将其设置为类成员。如果我不使用lambda上下文也可以。但是，如果设置了上下文，它将发出错误：

/home/user/Arduino/sketch_jan06b/sketch_jan06b.ino: In constructor 'CbSetter::CbSetter()':
sketch_jan06b:28:8: error: no matching function for call to 'CbReceptor::CbReceptor(CbSetter::CbSetter()::<lambda()>)'
       });
        ^
/home/user/Arduino/sketch_jan06b/sketch_jan06b.ino:9:5: note: candidate: CbReceptor::CbReceptor(Callback)
     CbReceptor(Callback callback)
     ^
/home/user/Arduino/sketch_jan06b/sketch_jan06b.ino:9:5: note:   no known conversion for argument 1 from 'CbSetter::CbSetter()::<lambda()>' to 'Callback {aka void (*)()}'
/home/user/Arduino/sketch_jan06b/sketch_jan06b.ino:4:7: note: candidate: constexpr CbReceptor::CbReceptor(const CbReceptor&)
 class CbReceptor
       ^
/home/user/Arduino/sketch_jan06b/sketch_jan06b.ino:4:7: note:   no known conversion for argument 1 from 'CbSetter::CbSetter()::<lambda()>' to 'const CbReceptor&'
/home/user/Arduino/sketch_jan06b/sketch_jan06b.ino:4:7: note: candidate: constexpr CbReceptor::CbReceptor(CbReceptor&&)
/home/user/Arduino/sketch_jan06b/sketch_jan06b.ino:4:7: note:   no known conversion for argument 1 from 'CbSetter::CbSetter()::<lambda()>' to 'CbReceptor&&'
exit status 1
no matching function for call to 'CbReceptor::CbReceptor(CbSetter::CbSetter()::<lambda()>)'

代码是：

typedef void (*Callback)();

class CbReceptor
{
    Callback cb;

  public:
    CbReceptor(Callback callback)
    {
      cb = callback;
      cb();
    }

};

class CbSetter
{
  public:
    CbSetter()
    {
      // Doesn't emit an error but dosn't have a context
      //Callback cb = [] () {};

      // emits error
      Callback cb = [=] () { contextMethod(); };

      CbReceptor* receptor = new CbReceptor(cb);
    }

  private:
    void contextMethod()
    {
      Serial.println("I've called!");
    }
};


void setup() {
  Serial.begin(9600);
  CbSetter* setter = new CbSetter();
}

void loop() {
}

也许我在想错方法。我很喜欢TypeScript，在JS中传递回调是很平常的事情，但是不幸的是，在C ++中却没有。也许还有其他方法可以将回调从另一个类传递到一个类。

在Arduino Web编辑器和Linux上本地安装的编辑器中，结果相同。

此问题与passing-capturing-lambda-as-function-pointer不同，因为真正的问题是将类方法作为上下文传递。在那个问题中，上下文只是静态函数中的一个变量。

如何将带有类构造函数内部上下文的lambda回调传递给Arduino上的其他类构造函数

0 个答案: