posish::fs
pub fn renameat<P: Arg, Q: Arg, PFd: AsRawFd, QFd: AsRawFd>( old_dirfd: &PFd, old_path: P, new_dirfd: &QFd, new_path: Q) -> Result<()>
renameat(old_dirfd, old_path, new_dirfd, new_path)