pi@raspberrypi:~$ gcc -o Video Video.c  -L/usr/local/lib -lwiringPi
/usr/lib/gcc/arm-linux-gnueabihf/4.6/../../../libwiringPi.so: undefined reference to `i2c_smbus_write_byte'
/usr/lib/gcc/arm-linux-gnueabihf/4.6/../../../libwiringPi.so: undefined reference to `i2c_smbus_read_byte'
/usr/lib/gcc/arm-linux-gnueabihf/4.6/../../../libwiringPi.so: undefined reference to `i2c_smbus_write_byte_data'
/usr/lib/gcc/arm-linux-gnueabihf/4.6/../../../libwiringPi.so: undefined reference to `i2c_smbus_write_word_data'
/usr/lib/gcc/arm-linux-gnueabihf/4.6/../../../libwiringPi.so: undefined reference to `i2c_smbus_read_word_data'
/usr/lib/gcc/arm-linux-gnueabihf/4.6/../../../libwiringPi.so: undefined reference to `i2c_smbus_read_byte_data'
collect2: ld returned 1 exit status