鏈接錯誤模板方法

Question

我在使用的連接器問題。

它給了我下面的錯誤：

[Linker error] undefined reference to `bool Polis :: deleteEdifice <Mine> (int) ' 

原型聲明如下：

template <typename T> bool deleteEdifice(int); 

deleteEdifice是空的，不，現在做任何事情，但它不工作。

原型的調用是：

obj->deleteEdifice<Mine>(3); 

我也試着這樣做：

obj->template deleteEdifice<Mine>(3); 

打印以下錯誤：

`template' (as a disambiguator) is only allowed within templates 

你能告訴我我是什麼做錯了。

Answer 1

這

template <typename T> bool deleteEdifice(int); 

並不意味着它是空的，這意味着它是不確定的，如錯誤[Linker error] undefined reference

這

template <typename T> bool deleteEdifice(int) { return false; } 

是空

Answer 2

I'm having problems with the linker. It gives me the following error: [Linker error] undefined reference to `bool Polis :: deleteEdifice (int) '

我「M假設你的代碼如下所示：

//.h file 
class Polis 
{ 
    public: 
    //...constructor etc... 
    template <class T> 
    bool deleteEdifice(int); 
}; 

同樣的.h文件

//, where definition of template is visible at 
// point of instantiation - remember, template is instantiated 
// when used (in compilation unit where used), therefore its 
// definition has to be visible in the scope where used. It is 
// only instantiated when used... If it's definition is not 
// available at the point of instantiation (where called for 
// a function template), it is never 
// compiled. 

template <class T> 
bool Polis::deleteEdifice(int) 
{ 
    //Implementation here... 
}