Fearless concurrency with Rust unless you are worried about lifecycle management, threads/co-operation and general ergonomics. Even modern c++ might be better at this (gasp!) with std::jthread
Are there any languages that provide for or care about lifecycle management across address space boundaries? After fork() you're usually fucked and need explicit controls.
So, std::jthread is basically fixing std::thread. In C++ it's difficult to fix broken standard library features so they just make a new thing and discard the old busted one. Landfill programming.
The fact Rust actually has scoped threads is unrelated, in Rust they can do this because they have working lifetime checking and in C++ such a feature would be meaningless, you're always assumed to have manually ensured the correct lifetimes and they aren't checked.
Generously you could say they're gesturing at the fact C++ decided to bolt the stop flag mechanic to jthreads, so you can have the old broken threads or this newer non-broken threads which also has built-in stop flags. But that's less choice, it's not as though you can't have a stop flag in Rust.
Ok, but I am literally getting filtered by installing C++ libraries. I haven't accomplished anything in the last 5 days other than determine that the previous libraries are not usable.