＆是什么QUOT; [这里]＆QUOT;意味着C ++

问题描述

当我读 Cocos2dx 3.0 API，我发现这样的事情：

 自动监听= [这]（事件*事件）{
    汽车的KeyboardEvent =的static_cast＆LT; EventKeyboard *＆GT;（事件）;
    如果（keyboardEvent-＆GT; _is pressed）
    {
        如果（安其pressed！= nullptr）
            安其pressed（keyboardEvent-＆GT; _key code，事件）;
    }
    其他
    {
        如果（onKeyReleased！= nullptr）
            onKeyReleased（keyboardEvent-＆GT; _key code，事件）;
    }
};
 

这是什么 [这] 是什么意思？在 C ++ 11 ？

这种新语法

解决方案

It introduces a lambda - a callable function object. Putting this in the brackets means that the lambda captures this, so that members of this object are available within it. Lambdas can also capture local variables, by value or reference, as described in the linked page.

The lambda has an overload of operator(), so that it can be called like a function:

Event * event = some_event();
listener(event);

which will run the code defined in the body of the lambda.

Yes.

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