Syntax: .IFNDEF symbolic-constant
Discussion: The .IFNDEF statement is a compiler directive. As such, it causes an action to occur when the program is compiled, not when the program is executed. The .IFNDEF directive can appear anywhere in an Internet Basic source program. As part of the conditional compilation feature of the Internet Basic compiler, the .IFNDEF directive is a variation on the .IF directive. It compiles the code segment only if the symbolic constant has not been defined (via the SET directive), or has been UNSET.