55: warning: unused variable 'vdd'

[h-Naima-s]

I am using MLX90640 evaluation board and Teensy 3.2. I have connected SCL of sensor to Pin 19 of Teensy and SDA to Pin 18. The MLX90640 evaluation board as well as Teensy 3.2 I have powered by connecting it to my computer, so I have not connected VDD and GND of sensor anywhere on Teensy. When I am uploading the code, I am getting following error and the code is not working.

P_Teeny: In function 'void loop()':
P_Teeny:55: warning: unused variable 'vdd'
float vdd = MLX90640_GetVdd(mlx90640Frame, &mlx90640);

What is wrong here? something with code or pin connections i made. Please guide.