c++ - 对象生存期内 `this`指针的值是否恒定？

Question

在特定对象的生存期内，this指针的值是否保证是恒定的？我无法想象情况会发生变化，但是不知道我是否没有错过任何东西。

Answer 1

Is the value of this pointer guaranteed to be constant during a lifetime of a particular object?

是。
正如用户 Aconcagua所说: this指针的值始终是在其上调用了on1的对象的地址的值。因此，问题等同于:

Can an object change its memory address over life time?

根据 lifetime 2的定义，这是不可能的。对象的生存期在获取对象的存储之时或之后开始，而在其释放之前终止。

1) [class.this]/1

In the body of a non-static ([class.mfct]) member function, the keyword this is a prvalue whose value is a pointer to the object for which the function is called.

2) [basic.life]/1 (重点是我的)

The lifetime of an object or reference is a runtime property of the object or reference. A variable is said to have vacuous initialization if it is default-initialized and, if it is of class type or a (possibly multi-dimensional) array thereof, that class type has a trivial default constructor.The lifetime of an object of type T begins when:

• storage with the proper alignment and size for type T is obtained, and
• its initialization (if any) is complete (including vacuous initialization) ([dcl.init]), except that if the object is a union member or subobject thereof, its lifetime only begins if that union member is the initialized member in the union ([dcl.init.aggr], [class.base.init]), or as described in [class.union].

The lifetime of an object o of type T ends when:

• if T is a non-class type, the object is destroyed, or
• if T is a class type, the destructor call starts, or
• the storage which the object occupies is released, or is reused by an object that is not nested within o ([intro.object]).