C++ 模板函数 : explicit instantiate one or more specializations

Question

是否可以显式实例化模板函数的一个或多个特化？其次，函数是否是类成员有关系吗？它是合法的 C++11 吗？它是否被编译器接受，因此不会出现问题？

Answer 1

Is it possible to explicit instantiate one or more specializations of a template function?

是的，但是，[temp.explicit]/5:

For a given set of template arguments, if an explicit instantiation of a template appears after a declaration of an explicit specialization for that template, the explicit instantiation has no effect.

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Second, does it matter if the function is a class member?

不，据我所知；[temp.explicit]/1:

A class, a function or member template specialization can be explicitly instantiated from its template. A member function, member class or static data member of a class template can be explicitly instantiated from the member definition associated with its class template. An explicit instantiation of a function template or member function of a class template shall not use the inline or constexpr specifiers.

来自 [temp.explicit]/3 的示例:

template<class T> class Array { void mf(); };
template class Array<char>;

template void Array<int>::mf();

template<class T> void sort(Array<T>& v) { /∗ ... ∗/ }
template void sort(Array<char>&);    // argument is deduced here

namespace N {
template<class T> void f(T&) { }
}
template void N::f<int>(int&);

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Is it legal C++11 and also is it accepted by compilers so it doesn't come with problems?

嗯，是的，但是对于库来说，总是存在 ABI 兼容性问题；特别是如果不同的编译器已用于库和库用户(例如，包含该库的程序)。 C++ 标准不指定 ABI。