is_error_code_available<T> - Boost.Outcome documentation

# `is_error_code_available<T>`

True if an error code can be constructed from a `T` e.g. if there exists an ADL discovered free function `make_error_code(T)`.

Overridable: By template specialisation into the `trait` namespace.

Default: True if `T` is an error code, else to metaprogramming which performs the ADL discovery of `make_error_code(T)`. Note that the STL defines multiple overloads of an ADL discovered free function `std::make_error_code(T)` for its error enumerations, as does Boost.System for the Boost error enumerations. Thus this trait will pick up those free functions for those error types.

Namespace: `BOOST_OUTCOME_V2_NAMESPACE::trait`

Header: `<boost/outcome/trait.hpp>`

Variable alias: `is_error_code_available_v<T>`

Last revised: February 05, 2019 at 21:41:47 UTC