I think you might be misunderstanding the intentions of this. AFAICT it's not a mechanism for supporting multiple interfaces, just a bit of a light trickery to

I think you might be misunderstanding the intentions of this. AFAICT it's not a mechanism for supporting multiple interfaces, just a bit of a light trickery to get a length passed into functions within the limitations of array->pointer decay in C. It also helps avoid cases where a miscalculated n is passed by 'encapsulating' it with the data. Edit: I stand corrected. Just had a look over the source and this does a lot more than the OP link indicates. The Github README is more informative.