22 Diagnostics library [diagnostics]

22.5 System error support [syserr]

22.5.3 Class error_­code [syserr.errcode]

22.5.3.4 Class error_­code observers [syserr.errcode.observers]

int value() const noexcept;
Returns: val_­.
const error_category& category() const noexcept;
Returns: *cat_­.
error_condition default_error_condition() const noexcept;
Returns: category().default_­error_­condition(value()).
string message() const;
Returns: category().message(value()).
explicit operator bool() const noexcept;
Returns: value() != 0.