@brief Read current value of a single GPIO line. @param line GPIO line object. @return 0 or 1 if the operation succeeds. On error this routine returns -1 and sets the last error number.
See Implementation
@brief Read current value of a single GPIO line. @param line GPIO line object. @return 0 or 1 if the operation succeeds. On error this routine returns -1 and sets the last error number.