Comment by kelnos

> I have never understood libraries or imterfaces that want me to allocate buffers for their type.

That doesn't seem that odd to me. It's a trade off: more flexibility, but more manual work. Maybe I have a buffer that I've allocated that I'm not using anymore (say I have a buffer pool) and want to use it again. If the type allocates its own behind the scenes, I can't do that. Or maybe I'm working in an environment where I need to statically allocate all of my resources up-front, and can't allocate later.

The big downside is that if 90% of people are just going to allocate a buffer and pass it in, it sucks that 90% of people need to do more work and understand more minutiae when only 10% of the people actually need to. The holy grail is to give lots of flexibility, but make the simple/common case easy.

A simple improvement to this interface might be to allow the caller to pass a zero-length buffer (or Zig's version of null), and then the type will allocate its own buffer. Of course, there's still a documentation burden so people know they can do that. Another option could be to have second constructor function that takes no buffer arguments at all, which allocates the buffers and passes them to the fully-flexible constructor function.