I don't see any reason why, in the few instances you actually intend to flush, you won't just say << std::flush. This will make it very clear that you intend to

I don't see any reason why, in the few instances you actually intend to flush, you won't just say << std::flush. This will make it very clear that you intend to flush the output. And we should definitely be prioritizing the documentation of our intentions over shaving a few bytes off of our source code file sizes. It was weird to ever merge two unrelated functions into something, and then name it something as cryptic as "endl". Especially when the most common case novices would encounter this would be std::cout, where terminals will automatically flush text to the screen upon receiving "\n" anyway.