# `const error_type &error() const &`

Wide contract const lvalue reference observer of the stored error. `NoValuePolicy::wide_error_check()` is first invoked, then the reference to the error is returned. As a valid default constructed error is always present, no undefined behaviour occurs if `NoValuePolicy::wide_error_check()` returns.

Note that if `error_type` is `void`, only a `const` overload returning `void` is present.

Requires: Always available.

Complexity: Depends on `NoValuePolicy::wide_error_check()`.

Guarantees: None.

Last revised: February 12, 2019 at 16:36:24 UTC