allocator::allocate

_Count

The number of elements for which sufficient storage is to be allocated.

_Hint

A const pointer that may assist the allocator object satisfy the request for storage by locating the address of an object allocated prior to the request.

A pointer to the allocated object or null if memory was not allocated.

The member function allocates storage for an array of count elements of type Type, by calling operator new(_Count). It returns a pointer to the allocated object. The hint argument helps some allocators in improving locality of reference; a valid choice is the address of an object earlier allocated by the same allocator object and not yet deallocated. To supply no hint, use a null pointer argument instead.

// allocator_allocate.cpp
// compile with: /EHsc
#include <memory>
#include <iostream>
#include <vector>

using namespace std;

int main( ) 
{
   allocator<int> v1Alloc;

   allocator<int>::pointer v1aPtr;

   v1aPtr = v1Alloc.allocate ( 10 );

   int i;
   for ( i = 0 ; i < 10 ; i++ )
   {
      v1aPtr[ i ] = i;
   }

   for ( i = 0 ; i < 10 ; i++ )
   {
      cout << v1aPtr[ i ] << " ";
   }
   cout << endl;

   v1Alloc.deallocate( v1aPtr, 10 );
}

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Header: <memory>

Namespace: std

Reference