I don't understand this article.

I think there is no language level feature in Rust to prevent TTCTTOU. TTCTTOU can happen in both c++ and rust.

for example:

    let f = File::open("username.txt");

    /*what if the file is deleted here?*/

    let mut f = match f {

        Ok(file) => /*what if the file is deleted here?*/ file,

        Err(e) => return Err(e),

    };

    /*what if the file is deleted here*/

I mean even if you write it like: let f = File::open("username.txt")?;

it looks atomic, it is not.

the c++ example, on the other hand, can do a filtering too, using:

http://www.cplusplus.com/reference/fstream/ifstream/is_open/

I mean Rust forces you to do error handling, which is nice. But that's not enough for preventing TTCTTOU. I don't think the first example is a strong argument.