Comment by EliRivers

Don't use standard library containers because we have our own containers that date back to before the STL was even stable.

Flashback to last job. Wrote their own containers. Opaque.

You ask for an item from it, you get back a void pointer. It's a pointer to the item. You ask for the previous, or the next, and you give back that void pointer (because it then goes through the data to find that one again, to know from where you want the next or previous) and get a different void pointer. No random access. You had to start with the special function which would give you the first item and go from there.

They screwed up the end, or the beginning, depending on what you were doing, so you wouldn't get back a null pointer if there was no next or previous. You had to separately check for that.

It was called an iterator, but it wasn't an iterator; an iterator is something for iterating over containers, but it didn't have actual iterators either.

When I opened it up, inside there was an actual container. Templated, so you could choose the real inside container. The default was a QList (as in Qt 4.7.4). The million line codebase contained no other uses; it was always just the default. They took a QList, and wrapped it inside a machine that only dealt in void pointers and stripped away almost all functionality, safety and ability to use std::algorithm

I suspect but cannot prove that the person who did this was a heavy C programmer in the 1980s. I do not know but suspect that this person first encountered variable data type containers that did this sort of thing (a search for "generic linked list in C" gives some ideas, for example) and when they had to move on to C++, learned just enough C++ to recreate what they were used to. And then made it the fundamental container class in millions of lines of code.