NAME

std::pmr::polymorphic_allocator::allocate - std::pmr::polymorphic_allocator::allocate

Synopsis

T* allocate( std::size_t n ); (since C++17)
(until C++20)
[[nodiscard]] T* allocate( std::size_t n ); (since C++20)

Allocates storage for n objects of type T using the underlying memory resource.
Equivalent to return static_cast<T*>(resource()->allocate(n * sizeof(T),
alignof(T)));.

Parameters

n - the number of objects to allocate storage for

Return value

A pointer to the allocated storage.

Exceptions

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

Defect reports

The following behavior-changing defect reports were applied retroactively to
previously published C++ standards.

DR Applied to Behavior as published Correct behavior
LWG 3038 C++17 allocate might allocate storage of wrong throws length_error
size instead
LWG 3237 C++17 the exception thrown by allocate was made consistent
inconsistent with std::allocator::allocate

See also

allocate_bytes Allocate raw aligned memory from the underlying resource
(C++20) (public member function)
allocate_object Allocates raw memory suitable for an object or an array
(C++20) (public member function)
new_object Allocates and constructs an object
(C++20) (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)