On windows, "atty" dereferences a potentially unaligned pointer. In practice however, the pointer won't be unaligned unless a custom global allocator is used. In particular, the "System" allocator on windows uses "HeapAlloc", which guarantees a large enough alignment. atty is Unmaintained A Pull Request with a fix has been provided over a year ago but the maintainer seems to be unreachable. Last release of "atty" was almost 3 years ago. Possible Alternative(s) The below list has not been vetted in any way and may or may not contain alternatives; - "std::io::IsTerminal" (https://doc.rust-lang.org/stable/std/io/trait.IsTerminal.html) - Stable since Rust 1.70.0 - "is-terminal" (https://crates.io/crates/is-terminal) - Standalone crate supporting Rust older than 1.70.0"