Syntax: .IFDEF symbolic-constant
Discussion: The .IFDEF 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 .IFDEF directive can appear anywhere in an Internet Basic source program. As part of the conditional compilation feature of the Internet Basic compiler, the .IFDEF directive is a variation on the .IF directive. It compiles the code segment only if the symbolic constant has been defined (via the SET directive), regardless of its value. Otherwise, the code segment is not compiled.