By value and by reference

Pass-by-value and pass-by-reference

NOTE: tag-Value semantic and reference semantic-pass

这两者是最最能够体现value-semantic和reference-semantic的。

Call-by-value and call-by-reference-pointer

NOTE: tag-Value semantic and reference semantic-call

1、C++中，只有call-by-reference-pointer才能够触发subtyping/dynamic polymorphism。

在 Subtyping-polymorphism # Reference semantic and runtime polymorphism 段中对此进行了非常详细的说明。

2、

	Call-by-value	Call-by-reference-pointer
	static bind	dynamic bind
	static type	dynamic type

下面是说明:

Call-by-value 对应的是 static bind ，使用的是 static type

Call-by-reference-pointer 对应的是 dynamic bind，使用的是 dynamic type

谈及这个topic的文章:

1、 stackoverflow What is object slicing? # A 中进行了详细介绍

2、nextptr shared_ptr - basics and internals with examples

其中谈及了"Call-by-value and call-by-reference-pointer"，已经收录了

TODO Return-by-value and return-by-reference

NOTE: NOTE: tag-Value semantic and reference semantic-return

draft

By value and by reference

显然by value涉及到copy，并且构造的对象在函数调用结束后就会被release掉；但是by reference则不存在。

This is not just a matter of convenience but in fact an optimization. If the parameter (s) binds to an lvalue (another non-const object), a copy of the object is made automatically while creating the parameter (s). However, when s binds to an rvalue (temporary object, literal), the copy is typically elided, which saves a call to a copy constructor and a destructor. In the earlier version of the assignment operator where the parameter is accepted as const reference, copy elision does not happen when the reference binds to an rvalue. This results in an additional object being created and destroyed.