模板规范得到“对重载函数的不明确调用”

Question

I'm working on a template function that could return a Collection or the first element in Collection , which stored some native pointers.

template<typename T>
class Collection
{
public:
    std::vector<T*> m_Container;
};

template<typename T>
T* GetGlobal()
{
    return &(*g_GlobalStrings.begin());
}

template<typename T>
Collection<T>* GetGlobal()
{
    auto res = std::vector<T*>(g_GlobalStrings.size());
    for (auto&& item : g_GlobalStrings)
    {
        res.push_back(&item);
    }
    return Collection<T>{res};
}

But compiler(MSVC) says:

error C2668: 'GetGlobal': ambiguous call to overloaded function.

I'm not sure how to implement this. Any help will be really appreciated.

Answer 1

Return type doesn't make difference on function signature so the call is ambigious.

You should use something like std::enable_if<>.

The only way to prevent ambiguity is that not enabling both functions for the same type. Another simpler way is to change the function names.