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std::pmr::polymorphic_allocator::allocate_object(3) C++ Standard Libary std::pmr::polymorphic_allocator::allocate_object(3)

NAME

std::pmr::polymorphic_allocator::allocate_object - std::pmr::polymorphic_allocator::allocate_object

Synopsis


template< class U > (since C++20)
[[nodiscard]] U* allocate_object( std::size_t n = 1 );


Allocates storage for n objects of type U using the underlying memory resource.


If std::numeric_limits<std::size_t>::max() / sizeof(U) < n, throws
std::bad_array_new_length, otherwise equivalent to return
static_cast<U*>(allocate_bytes(n * sizeof(U), alignof(U)) );

Parameters


n - the number of objects to allocate storage for

Return value


A pointer to the allocated storage.

Notes


This function was introduced for use with the fully-specialized allocator
std::pmr::polymorphic_allocator<>, but it may be useful in any specialization as a
shortcut to avoid having to rebind from std::pmr::polymorphic_allocator<T> to
std::pmr::polymorphic_allocator<U>.


Since U is not deduced, it must be provided as a template argument when calling this
function.

Exceptions


Throws std::bad_array_new_length if n > std::numeric_limits<std::size_t>::max() /
sizeof(U); may also be any exceptions thrown by the call to resource()->allocate.

See also


allocate_bytes Allocate raw aligned memory from the underlying resource
(C++20) (public member function)
new_object Allocates and constructs an object
(C++20) (public member function)
allocate Allocate memory
(public member function)
allocate allocates uninitialized storage using the allocator
[static] (public static member function of std::allocator_traits<Alloc>)
allocate allocates memory
(public member function of std::pmr::memory_resource)

2022.07.31 http://cppreference.com