循环C ++头包括 [英] Circular C++ Header Includes

问题描述

在一个项目中，我有两个类：

In a project I have 2 classes:

// mainw.h

// mainw.h

#include "IFr.h"
...
class mainw
{
public:
static IFr ifr;
static CSize=100;
...
};

// IFr.h

#include "mainw.h"
...
class IFr
{
public float[mainw::CSize];
};

但是我无法编译这个代码，在 ; 行。是否禁止这种交叉包含？

But I cannot compile this code, getting an error at the static IFr ifr; line. Is this kind of cross-inclusion prohibited?

推荐答案

？

Is this kind of cross-inclusions are prohibited?

是的。

一种解决方法是说mainw的ifr成员是一个引用或指针，所以前向声明将做而不是包括完整的声明，如：

A work-around would be to say that the ifr member of mainw is a reference or a pointer, so that a forward-declaration will do instead of including the full declaration, like:

//#include "IFr.h" //not this
class IFr; //this instead
...
class mainw
{
public:
static IFr* ifr; //pointer; don't forget to initialize this in mainw.cpp!
static CSize=100;
...
}

头文件（以便Ifr.h可以包括这个其他头文件，而不包括mainw.h）。

Alternatively, define the CSize value in a separate header file (so that Ifr.h can include this other header file instead of including mainw.h).

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