(Command-line option to suppress warning: -w-rng) 

Your source file includes a comparison involving a constant sub-expression that was outside the range allowed by the other sub-expression's type. 

For example, comparing an unsigned quantity to -1 makes no sense. 

To get an unsigned constant greater than 32,767 (in decimal), you should either

• cast the constant to unsigned--for example, (unsigned) 65535, or
• append a letter u or U to the constant--for example, 65535u.

Whenever this message is issued, the compiler still generates code to do the comparison. 

If this code ends up always giving the same result (such as comparing a char expression to 4000), the code will still perform the test.