A generic dynamic array in C that stores no capacity and needs no struct

A developer has created a generic dynamic array implementation in C that uses a two-pointer array to store both data and length without requiring a struct, by encoding the length directly in a pointer value. The design avoids storing capacity by default, instead computing it on-demand as the next power of two when needed, though it optionally supports explicit capacity tracking through a three-pointer array variant for cases where that's beneficial.