The #define Statement
The #define statement is used to create new macro variables and change the value of existing ones. It has the following syntax:
# define $variable [expr | bool_expr]
$variable
Specifies the name of the macro variable. The leading $ is required.
expr
Specifies the character or integer expression assigned to the macro variable. Character strings must be delimited with single quotation marks.
bool_expr
Specifies an expression that evaluates to TRUE or FALSE
For example, to define a macro variable, for a default color, you would use the following statement:
# define $defaultcolor 'CC_LIGHT_GRAY'