当一个类声明显示有两个名称时，是什么意思？ [英] What does it mean when a class declaration appears to have two names?

问题描述

我想了解一些具有以下类语法的C ++代码：

I'm trying to understand some C++ code which has the following class syntax:

class Q_MONKEY_EXPORT BasePlugin : public QObject
{
    // some code comes here
};

我不明白语法 class Q_MONKEY_EXPORT BasePlugin 。对我来说，看起来像是有两个名字的类。这种语法在C ++中到底意味着什么？

I cannot understand the syntax class Q_MONKEY_EXPORT BasePlugin. To me it looks like if there are two names for the class. What exactly does this kind of syntax mean in C++?

推荐答案

Q_MONKEY_EXPORT很可能是一个#define。有时需要定义类，例如当类位于库中并且需要在头文件包含在其他位置时导出。在这种情况下，define解析为 __ declspec（dllexport）（确切的语法将取决于您使用的工具）。

Q_MONKEY_EXPORT is most likely a #define somewhere. Defines like that are sometimes required, for example when the class is in a library and needs to be exported when the header file is included from somewhere else. In that case, the define resolves to something like __declspec(dllexport) (the exact syntax will depend on the tools you are using).

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