@brief Reserve a single line, set the direction to output.
@param line GPIO line object.
@param consumer Name of the consumer.
@param flags Additional request flags.
@param default_val Initial line value.
@return 0 if the line was properly reserved, -1 on failure.
@brief Reserve a single line, set the direction to output. @param line GPIO line object. @param consumer Name of the consumer. @param flags Additional request flags. @param default_val Initial line value. @return 0 if the line was properly reserved, -1 on failure.