std::pmr::memory_resource::deallocate (3) - Linux Man Pages
void deallocate(void* p,
std::size_t bytes, (since C++17)
std::size_t alignment = alignof(std::max_align_t));
Deallocates the storage pointed to by p. p shall have been returned by a prior call to allocate(bytes, alignment) on a memory_resource that compares equal to *this, and the storage it points to shall not yet have been deallocated.
Equivalent to do_deallocate(p, bytes, alignment);.
do_deallocate deallocates memory