"undefined reference" to functions I have certainly included
I am writing a program in C that needs to use colored text (DOS-type, 16 colors). I decided to use the color functions in conio.h because it seemed easiest and had everything I needed, but the compiler reports undefined references to the functions at the lines they are used, but I did include conio.h at the beginning of the file and with proper notation. I am also sure that I spelled the function correctly and used the correct parameters.
What is the problem here?