empty value {{{_state._value}}} error {{{_state._error}}} exception {{{_ptr}}} error + exception {{{_state._error}}} + {{{_ptr}}} error (errno) {{{_state._error}}} error (errno) + exception {{{_error}}} + {{{_ptr}}} value (moved from) {{{_state._value}}} error (moved from) {{{_state._error}}} exception (moved from) {{{_ptr}}} error + exception (moved from) {{{_state._error}}} + {{{_ptr}}} error (errno, moved from) {{{_state._error}}} error (errno, moved from) + exception {{{_error}}} + {{{_ptr}}} unknown _state._value _state._error _ptr empty value {{{_state._value}}} error {{{_state._error}}} error (errno) {{{_state._error}}} value (moved from) {{{_state._value}}} error (moved from) {{{_state._error}}} error (errno, moved from) {{{_state._error}}} unknown _state._value _state._error