CTL_STATUS_t ctl_bus_read_bit(CTL_PARALLEL_BUS_t *self, unsigned bit);
ctl_bus_read_bit reads bit number bit from the bus self.
ctl_bus_read_bit returns an extended status code: 0 if the port bit is low, 1 if the port bit is high, and a negative value indicating an error.
ctl_bus_read_bit is thread-safe if a mutex is associated with the bus self.