如何定义模板类的模板成员函数 [英] How to define a template member function of a template class

问题描述

可能重复:
如何执行我在类定义之外的模板类中定义了模板函数?

在模板类中具有模板成员函数的情况下，我在语法上苦苦挣扎:

I'm struggling with the syntax for the case where I have a template member function within a template class:

template <typename T> class Foo
{
    void Bar(const T * t);
    template <typename T2> void Bar(const T2 * t);
};

template <typename T> void Foo<T>::Bar(const T * t)
{
    // ... no problem ...
}

template <typename T> void Foo<T>::Bar<typename T2>(const T2 * t)
{
    // ... this is where I'm tearing my hair out ...
}

第一个成员函数很好，但是处理模板类的基本类型以外的类型的模板成员函数是我遇到问题的地方.对于上述情况，我得到以下错误:

The first member function is fine, but the template member function which handles types other than the base type of the template class is where I am having problems. For the above case I get the following errors:

template_problem.cpp:12: error: parse error in template argument list
template_problem.cpp:12: error: expected ‘,’ or ‘...’ before ‘*’ token
template_problem.cpp:12: error: ISO C++ forbids declaration of ‘T2’ with no type
template_problem.cpp:12: error: template-id ‘Bar<<expression error> >’ in declaration of primary template
template_problem.cpp:12: error: prototype for ‘void Foo<T>::Bar(int)’ does not match any in class ‘Foo<T>’
template_problem.cpp:4: error: candidates are: template<class T> template<class T2> void Foo::Bar(const T2*)
template_problem.cpp:7: error:                 void Foo<T>::Bar(const T*)
template_problem.cpp:12: error: template definition of non-template ‘void Foo<T>::Bar(int)’

，而且我还尝试了 Bar 的模板版本可以想到的所有其他语法变体.

and I've also tried every other syntax variation I can think of for the template version of Bar.

推荐答案

template<typename T>
template<typename T2>
void Foo<T>::Bar(const T2* t) 
{
     // stop tearing your hair out
}

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