A lot of times libraries want to have a C-callable ABI. This means you don't see a lot of C++ features in use between library boundaries, even if they use a lo

A lot of times libraries want to have a C-callable ABI. This means you don't see a lot of C++ features in use between library boundaries, even if they use a lot of it internally. Also, further back in history, the ABIs for a lot of C++ features were subject to change. If you used g++ on Linux in the 90s and 2000s you've been bit by this. I'm not sure if this still happens in the modern era with the standards still iterating a lot; would not surprise me if it still does. This is another reason to avoid interfaces with a high risk of breaking ABI, which C++ features can be.