类成员函数模板可以是虚拟的吗？ [英] Can a class member function template be virtual?

问题描述

我听说C ++类成员函数模板不能是虚拟的。这是真的？

I have heard that C++ class member function templates can't be virtual. Is this true?

如果它们可以是虚拟的，那么使用这种功能的情况的例子是什么？

If they can be virtual, what is an example of a scenario in which one would use such a function?

推荐答案

模板都是有关编译器在 compile-time 时生成代码的。虚拟函数都是关于运行时系统的，用于确定在运行时中调用哪个函数。

Templates are all about the compiler generating code at compile-time. Virtual functions are all about the run-time system figuring out which function to call at run-time.

一旦运行时系统发现需要调用模板化的虚拟函数，编译就完成了，并且编译器无法再生成适当的实例了。因此，您不能具有虚拟成员功能模板。

Once the run-time system figured out it would need to call a templatized virtual function, compilation is all done and the compiler cannot generate the appropriate instance anymore. Therefore you cannot have virtual member function templates.

但是，结合多态性和模板有一些强大而有趣的技术，尤其是所谓的 类型擦除 。

However, there are a few powerful and interesting techniques stemming from combining polymorphism and templates, notably so-called type erasure.

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