stl allocator::rebind

allocator::rebind

   看侯捷先生的《STL源码剖析》，第二章将空间配置器中提到allocator::rebind，不知所云。查了一下MSDN，才略懂一些，摘到此。

allocator::rebind

功能：

A structure that enables an allocator for objects of one type to allocate storage for objects of another type.

实现：

template<class _Other>

struct rebind

{

   typedef allocator<_Other> other;

};

参数：

other  The type of element for which memory is being allocated.

标注：

This structure is useful for allocating memory for type that differs from the element type of the container being implemented.

The member template class defines the type other. Its sole purpose is to provide the type name allocator<_Other>, given the type name allocator<Type>.

   For example, given an allocator object al of type A, you can allocate an object of type _Other with the expression:

CopyA::rebind<Other>::other(al).allocate(1, (Other *)0)

Or, you can name its pointer type by writing the type:

CopyA::rebind<Other>::other::pointer

Example

--------------------------------------------------------------------------------

// allocator_rebind.cpp

// compile with: /EHsc

#include <memory>

#include <iostream>

#include <algorithm>

#include <vector>

 

using namespace std;

 

typedef vector<int>::allocator_type IntAlloc;

int main( )

{

   IntAlloc v1Iter;

   vector<int> v1;

 

   IntAlloc::rebind<char>::other::pointer pszC =

      IntAlloc::rebind<char>::other(v1.get_allocator()).allocate(1, (void *)0);

 

   int * pInt = v1Iter.allocate(10);

}

头文件：

--------------------------------------------------------------------------------

Header: <memory>