Creates and releases compile-time constants.
You can use the #DEFINE and #UNDEF preprocessor directives to create compile-time constants in programs. By creating constants with #DEFINE instead of using variables, you can reduce memory consumption, increase performance, and simplify programs.
To create a constant with #DEFINE, specify the constant's name with ConstantName and its value with eExpression. When the program is compiled, text substitution is performed and the constant value expression is substituted for the constant name wherever it appears in the program. You can stop the substitution for the constant by issuing #UNDEF.