# Function std::error::request_value

source ·

    pub fn request_value<T, 'a>(err: &'a (impl Error + ?Sized)) -> Option<T>where
        T: 'static,

🔬This is a nightly-only experimental API. (`error_generic_member_access` #99301)
Expand description

Request a value of type `T` from the given `impl Error`.

## Examples

Get a string value from an error.

    use std::error::Error;
    use core::error::request_value;

    fn get_string(err: &impl Error) -> String {
        request_value::<String>(err).unwrap()
    }

Run