text: #include "unistd.h"
  #include "math.h"
  #include "stdint.h"
  
  // From common.c
  void hal_gpio_on(void);
  void hal_gpio_off(void);
  void hal_gpio_init(void);
  int hal_i2c_init(int devID);
  void hal_i2c_deinit(void);
  void hal_i2c_write(int fd, uint8_t reg, uint8_t value);
  uint8_t hal_i2c_read(int fd, uint8_t reg);
  void hal_i2c_BulkRead(int fd, uint8_t reg, uint8_t len, uint8_t *buf);
  int32_t magnitude(int32_t x, int32_t y, int32_t z);
  int32_t findArctan(double x, double y);
  int32_t upness(int32_t x, int32_t y, int32_t z);
  double toAngle(int x);
  
  // From accel.c
  void accel_init(void);
  void accel_read(void);
  int32_t accel_x(void);
  int32_t accel_y(void);
  int32_t accel_z(void);
  
  // From baro3115.c
  void baro_init(void);
  void turnOnBaro(void);
  void turnOffBaro(void);
  int32_t baro_alt(void);
  int32_t baro_press(void);
  int32_t baro_temp(void);
  
  // From mag3110.c
  void  mag_init(void);
  int32_t magnet_x();
  int32_t magnet_y();
  int32_t magnet_z();
  int32_t mag_compass(int32_t pitch, int32_t roll);
  
  
  