std::allocator_traits::allocate (3) Linux Manual Page

std::allocator_traits<Alloc>::allocate – std::allocator_traits<Alloc>::allocate

Synopsis

Defined in header <memory>

static pointer allocate( Alloc& a, size_type n );                       (since C++11)
(until C++20)

[[nodiscard]] static pointer allocate( Alloc& a, size_type n );         (since C++20)

static pointer allocate( Alloc& a, size_type n,                 (1)                    (since C++11)

const_void_pointer hint );                                          (2)                (until C++20)

[[nodiscard]] static pointer allocate( Alloc& a, size_type n,                          (since C++20)

const_void_pointer hint );

Uses the allocator a to allocate n*sizeof(Alloc::value_type) bytes of uninitialized storage.
1) Calls a.allocate(n)
2) Additionally passes memory locality hint hint. Calls a.allocate(n, hint) if possible. If not possible (e.g. a has no two-argument member function allocate()), calls a.allocate(n)

Parameters

a – allocator to use
n – the number of objects to allocate storage for
hint – pointer to a nearby memory location

Return value

The pointer returned by the call to a.allocate(n)

See also

         allocates uninitialized storage
allocate (public member function of std::allocator<T>)