Clyde R. Schrank

Hello, i was trying to connect sensors via i2c, and neither wiringPi.h nor i2c-dev.h are comiting Read/Write comands. The file descriptor is given a value, so i think the connection worked, but functions like : i2c_smbus_read_byte_data(FILEDESCRIPTOR, (u_int8_t)REGISTERADRESS) just pop errors. Do you guys have any idea? Thanks for any help! edit: i have also included /linux/i2c.h and the function error persists. "I2C_SMBUS_READ_BYTE_DATA was not declared in this scope"