bus VS winlamb

I would say channels. In this case, a single producer, multiple consumer (spmc) broadcast channel, like bus. I can't vouch for this library, but it seems to do what you're looking for

The first thing that came into my mind was: why not simply go fully native, with the aid of something like WinLamb? Often you can roll your own custom controls quicker than a cross-platform library.

With WinLamb it's trivial: just create a field in the class.

However, if you still want to go Win32, this library is a thin wrapper which may save you a lot of time (and sanity). However, it's C++, not C.

I write C++ and raw Win32 for more than 20 years. I'm the author of this, and I'm rewriting my personal stuff in Rust just for fun.

I wrote a very thin C++11 wrapper for Win32 a few years ago, in case you're interested: WinLamb. It won't do everything, it just covers window creation and messaging, and leaves room to plug any other Win32 stuff on top of it.

Take a look at WinLamb source if you want to see how to build a native GUI.

Given my C++ Win32 background, the very first thing I tried was to write a native Win32 GUI app in Rust. It later became the WinSafe crate, which is strikingly similar to WinLamb C++ lib. The Rust experience was awesome. The correctness of the type system was something I really appreciated, things C++ cannot give you.

I write native Windows stuff sometimes, and I use Windigo, which I wrote based on my WinLamb C++ lib. It's a GUI system over raw Win32, so this has the disadvantage that you'll have to learn some Win32... but it has the advantage that you have the unleashed power of Win32 at your fingertips.