pointer_traits Struct

Artikkeli
08/03/2021

Supplies information that is needed by an object of type allocator_traits to describe an allocator with pointer type Ptr.

Syntax

template <class Ptr>
    struct pointer_traits;

Remarks

Ptr can be a raw pointer of type Ty * or a class with the following properties.

struct Ptr
{ // describes a pointer type usable by allocators
   typedef Ptr pointer;
   typedef T1 element_type; // optional
   typedef T2 difference_type; // optional
   template <class Other>
   using rebind = typename Ptr<Other, Rest...>; // optional
   static pointer pointer_to(element_type& obj); // optional
};

Members

Typedefs

Name	Description
`typedef T2 difference_type`	The type `T2` is `Ptr::difference_type` if that type exists, otherwise `ptrdiff_t`. If `Ptr` is a raw pointer, the type is `ptrdiff_t`.
`typedef T1 element_type`	The type `T1` is `Ptr::element_type` if that type exists, otherwise `Ty`. If `Ptr` is a raw pointer, the type is `Ty`.
`typedef Ptr pointer`	The type is `Ptr`.

Structs

Name	Description
`rebind`	Attempts to convert the underlying pointer type to a specified type.

Methods

Name	Description
pointer_to	Converts an arbitrary reference to an object of class `Ptr`.

pointer_to

Static method that returns Ptr::pointer_to(obj), if that function exists. Otherwise, it is not possible to convert an arbitrary reference to an object of class Ptr. If Ptr is a raw pointer, this method returns addressof(obj).

static pointer pointer_to(element_type& obj);

Jaa