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Showing content from https://cplusplus.com/map::get_allocator below:

public member function

<map>

std::map::get_allocator 
allocator_type get_allocator() const;
allocator_type get_allocator() const noexcept;

Get allocator

Returns a copy of the allocator object associated with the map.

Parameters none

Return Value The allocator.

Member type allocator_type is the type of the allocator used by the container, defined in map as an alias of its fourth template parameter (Alloc).



Example 
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// map::get_allocator
#include <iostream>
#include <map>

int main ()
{
  int psize;
  std::map<char,int> mymap;
  std::pair<const char,int>* p;

  // allocate an array of 5 elements using mymap's allocator:
  p=mymap.get_allocator().allocate(5);

  // assign some values to array
  psize = sizeof(std::map<char,int>::value_type)*5;

  std::cout << "The allocated array has a size of " << psize << " bytes.\n";

  mymap.get_allocator().deallocate(p,5);

  return 0;
}
The example shows an elaborate way to allocate memory for an array of pairs using the same allocator used by the container.
A possible output is: 
The allocated array has a size of 40 bytes.


Complexity Constant.

Iterator validity No changes.

Data races The container is accessed.
No contained elements are accessed: concurrently accessing or modifying them is safe.

Exception safetyNo-throw guarantee: this member function never throws exceptions.
Copying any instantiation of the default allocator is also guaranteed to never throw.

See also
allocator
Default allocator (class template)

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