return fmt.Errorf("creating meta-data file %s: %v", s.mftmp, err)
		}
	}
	return nil
}

// openCounterFile opens an output file for the counter data portion
// of a test coverage run. If updates the 'cfname' and 'cf' fields in
// 's', returning an error if something went wrong.
func (s *emitState) openCounterFile(metaHash [16]byte) error {
	processID := os.Getpid()