18 Diagnostics library [diagnostics]

18.5 System error support [syserr]

18.5.2 Class error_­category [syserr.errcat] Virtual members [syserr.errcat.virtuals]

virtual ~error_category();
Effects: Destroys an object of class error_­category.
virtual const char* name() const noexcept = 0;
Returns: A string naming the error category.
virtual error_condition default_error_condition(int ev) const noexcept;
Returns: error_­condition(ev, *this).
virtual bool equivalent(int code, const error_condition& condition) const noexcept;
Returns: default_­error_­condition(code) == condition.
virtual bool equivalent(const error_code& code, int condition) const noexcept;
Returns: *this == code.category() && code.value() == condition.
virtual string message(int ev) const = 0;
Returns: A string that describes the error condition denoted by ev.