内联函数的 gtest 问题

发布于 2024-11-04 09:46:29 字数 724 浏览 0 评论 0原文

你好，我有包含内联函数，当我尝试用谷歌测试测试这个类时，我有这样的错误：

 error LNK2019: unresolved external symbol "public: double __thiscall Math::returnPi(void)" (?returnPi@Math@@QAENXZ) referenced in function "private: virtual void __thiscall Speed_Math_Test::TestBody(void)" (?TestBody@Speed_Math_Test@@EAEXXZ)

例如我的类（头文件）

class Math
{
public:
    Math(void);
    inline double returnPi();
    ~Math(void);
};

我的类（cpp文件）

Math::Math(void)
{}
Math::~Math(void)
{}
double Math::returnPi()
{ return 3.14;}

测试：

TEST(EQ, Math)
{
    Math *m=new Math();
    EXPECT_EQ(3.14,m->returnPi());
}

我需要做什么？我阅读了手册，但不知道如何解决此错误。

原文

hello i have which include inline function, when i try testing this class with google test, i have error like:

 error LNK2019: unresolved external symbol "public: double __thiscall Math::returnPi(void)" (?returnPi@Math@@QAENXZ) referenced in function "private: virtual void __thiscall Speed_Math_Test::TestBody(void)" (?TestBody@Speed_Math_Test@@EAEXXZ)

for example my class(header file)

class Math
{
public:
    Math(void);
    inline double returnPi();
    ~Math(void);
};

my class(cpp file)

Math::Math(void)
{}
Math::~Math(void)
{}
double Math::returnPi()
{ return 3.14;}

test:

TEST(EQ, Math)
{
    Math *m=new Math();
    EXPECT_EQ(3.14,m->returnPi());
}

what i need to do? i read manual but dont see how i can resolved this error.

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抽个烟儿 2024-11-11 09:46:29

内联函数应该位于您的头文件中，而不是位于源文件中，因此它实际上可以由调用者（无权访问源文件）内联。

此外，如果您给出了函数的定义，则无需在类声明中指定inline。

因此，您的标头应变为：

class Math
{
public:
    Math(void);
    double returnPi() { return 3.14; } // no need to specify inline here
    ~Math(void);
};

并从源文件中删除 returnPi() 的定义。

请注意，您也可以这样做：

class Math
{
public:
    Math(void);
    double returnPi();
    ~Math(void);
};


inline double Math::returnPi() { return 3.14; } // inline is mandatory here to avoid respecting the "One Definition Rule"

如果您想将类声明与函数定义分开，则第二种解决方案很好。

另请注意，inline 并不保证实际的函数调用将被内联：它强制执行的唯一一件事是您不必遵守“单一定义规则”：inline< /code> 函数在所有翻译单元中必须具有相同的定义。

An inline function should be in your header file, not in your source file so it can actually be inlined by the callers (which don't have access to the source file).

Moreover, you don't need to specify inline in your class declaration if you give the definition of the function.

So your header should become:

class Math
{
public:
    Math(void);
    double returnPi() { return 3.14; } // no need to specify inline here
    ~Math(void);
};

And remove the definition for returnPi() from your source file.

Note that you could also have done:

class Math
{
public:
    Math(void);
    double returnPi();
    ~Math(void);
};


inline double Math::returnPi() { return 3.14; } // inline is mandatory here to avoid respecting the "One Definition Rule"

The second solution is good if you want to keep the class declaration separate from the function definition.

Also note that inline does not guarantees that the actual function calls will be inlined: the only thing it enforces is that you don't have to respect the "One Definition Rule": the inline function must have the same definition in all translation units.

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