Observers
`auto as_failure() const &`
Return the output from free function auto failure(T &&, ...) containing a copy of any errored state. The error state is accessed using const error_type &assume_error() const & noexcept . Requires: Always available. Complexity: Whatever that of error_type’s copy constructor is. Guarantees: None. »
`bool has_error() const noexcept`
Returns true if an error is present. Constexpr where possible. Requires: Always available. Complexity: Constant time. Guarantees: Never throws an exception. »
`bool has_error() const noexcept`
Returns true if an error is present. Constexpr where possible. Requires: Always available. Complexity: Constant time. Guarantees: Never throws an exception. »
`bool has_exception() const noexcept`
Returns true if an exception is present. Constexpr where possible. Requires: Always available. Complexity: Constant time. Guarantees: Never throws an exception. »
`bool has_exception() const noexcept`
Always returns false for basic_result. Constexpr where possible. Requires: Always available. Complexity: Constant time. Guarantees: Never throws an exception. »
`bool has_failure() const noexcept`
Returns true if there is either an error or an exception. Constexpr where possible. Requires: Always available. Complexity: Constant time. Guarantees: Never throws an exception. »
`bool has_failure() const noexcept`
Returns true if there is either an error or an exception. Constexpr where possible. Requires: Always available. Complexity: Constant time. Guarantees: Never throws an exception. »
`bool has_lost_consistency() const noexcept`
Returns true if a preceding swap involving this object failed to preserve the strong guarantee. Constexpr where possible. Requires: Always available. Complexity: Constant time. Guarantees: Never throws an exception. »
`bool has_value() const noexcept`
Returns true if a value is present. Constexpr where possible. Alias for explicit operator bool() const noexcept . Requires: Always available. Complexity: Constant time. Guarantees: Never throws an exception. »
`bool has_value() const noexcept`
Returns true if a value is present. Constexpr where possible. Alias for explicit operator bool() const noexcept . Requires: Always available. Complexity: Constant time. Guarantees: Never throws an exception. »