Function extendr_api::functions::na_str

pub fn na_str() -> &'static str

Special "NA" string that represents null strings.

use extendr_api::prelude::*;
test! {
    assert!(na_str().as_ptr() != "NA".as_ptr());
    assert_eq!(na_str(), "NA");
    assert_eq!("NA".is_na(), false);
    assert_eq!(na_str().is_na(), true);
}