Return a newly allocated block of memory of (at least) the specified positive size (in bytes). If size is 0, a null pointer is returned with no other effect. If this allocator cannot return the requested number of bytes, then it will return a null pointer. The behavior is undefined unless 0 <= size. Note that the alignment of the address returned is the maximum alignment for any type defined on this platform. Also note that std::malloc is not called when size is 0 (in order to avoid having to acquire a lock, and potential contention in multi-treaded programs).