Class template new

Class template new_allocator

boost::container::new_allocator

Synopsis

// In header: <boost/container/new_allocator.hpp>

template<typename T> 
class new_allocator {
public:
  // types
  typedef T                      value_type;                            
  typedef T *                    pointer;                               
  typedef const T *              const_pointer;                         
  typedef T &                    reference;                             
  typedef const T &              const_reference;                       
  typedef std::size_t            size_type;                             
  typedef std::ptrdiff_t         difference_type;                       
  typedef implementation_defined propagate_on_container_move_assignment;  // A integral constant of type bool with value true. 
  typedef implementation_defined is_always_equal;                         // A integral constant of type bool with value true. 

  // member classes/structs/unions
  template<typename T2> 
  struct rebind {
    // types
    typedef new_allocator< T2 > other;
  };

  // public member functions
  new_allocator() noexcept;
  new_allocator(const new_allocator &) noexcept;
  new_allocator & operator=(const new_allocator &) noexcept;
  template<typename T2> new_allocator(const new_allocator< T2 > &) noexcept;
  pointer allocate(size_type);
  void deallocate(pointer, size_type) noexcept;
  size_type max_size() const noexcept;

  // friend functions
  void swap(new_allocator &, new_allocator &) noexcept;
  bool operator==(const new_allocator &, const new_allocator &) noexcept;
  bool operator!=(const new_allocator &, const new_allocator &) noexcept;
};

Description

This class is a reduced STL-compatible allocator that allocates memory using operator new or compatible calls. This allocator is stateless and can be used with any type. It supports overaligned types, even if the compiler does not support overaligned operator new. It is a drop-in replacement for std::allocator

`new_allocator` public member functions

```
new_allocator() noexcept;
```
Default constructor Never throws

new_allocator(const new_allocator &) noexcept;

Constructor from other new_allocator. Never throws

new_allocator & operator=(const new_allocator &) noexcept;

Copy assignment operator from other new_allocator. Never throws

template<typename T2> new_allocator(const new_allocator< T2 > &) noexcept;

Constructor from related new_allocator. Never throws

```
pointer allocate(size_type count);
```
Allocates memory for an array of count elements. Throws bad_alloc if there is no enough memory

void deallocate(pointer ptr, size_type n) noexcept;

Deallocates previously allocated memory. Never throws

```
size_type max_size() const noexcept;
```
Returns the maximum number of elements that could be allocated. Never throws

`new_allocator` friend functions

```
void swap(new_allocator &, new_allocator &) noexcept;
```
Swaps two allocators, does nothing because this new_allocator is stateless
```
bool operator==(const new_allocator &, const new_allocator &) noexcept;
```
An new_allocator always compares to true, as memory allocated with one instance can be deallocated by another instance
```
bool operator!=(const new_allocator &, const new_allocator &) noexcept;
```
An new_allocator always compares to false, as memory allocated with one instance can be deallocated by another instance

Specializations

Class new_allocator<void>