extrusive

Is there a difference between intrusive and extrusive list when the member type is a struct (value type)?

If you're teaching generic programming you might want both (single and double) extrusive linked list types for your explanation.

There might be a few, but a dynamic array is (and has always been?) usually preferable to an extrusive list.

The advantage of extrusive linked lists is that you don't need to modify the data layout of Member at all.

An extrusive list puts the pointers in a separate node structure, which then has a pointer to the actual member type.

That depends on which array & extrusive linked list classes you’re talking about.

The vector takes less memory (1 pointer per element, with a max of 50% overhead, while an extrusive doubly-linked list is 3 pointers per element).

There are about two dozen stone types that form layers, divided quasi-realistically into sedimentary, igneous intrusive, igneous extrusive, and metamorphic [1].

The advantage versus your extrusive example is that the payload doesn't need to be referenced through a pointer, which drastically simplifies lifetime tracking / memory management.

I don’t know many good reasons for extrusive linked lists, even before caches.

Of course, things can be incredibly hard - but even in the poorest regions under the most extrusive of governments, there are ways to carve out niches.

There's just little reason to use an extrusive linked list because the use-cases where intrusive linked lists are not better are precisely the same ones where vectors are better.

The extrusive example I posted gives "inclusion into multiple lists".

Extrusive linked lists (like you might see in a class library or CS 101 project), where the node structure is heap-allocated separately from the data that it points to, have very few practical advantages over vectors, which is why standard libraries are increasingly defaulting to vectors even when the class is named "list".

Extrusive linked lists, however, have very few advantages over vectors (which also require heap allocation but are more cache & locality friendly).