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)));.
| n | - | the number of objects to allocate storage for |
A pointer to the allocated storage.
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.
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 size | throws length_error instead |
| LWG 3237 | C++17 | the exception thrown by allocate was inconsistent with std::allocator::allocate | made consistent |
|
(C++20) | allocate raw aligned memory from the underlying resource (public member function) |
|
(C++20) | allocates raw memory suitable for an object or an array (public member function) |
|
(C++20) | allocates and constructs an object (public member function) |
|
[static] | allocates uninitialized storage using the allocator (public static member function of std::allocator_traits<Alloc>) |
| allocates memory (public member function of std::pmr::memory_resource) |
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