Introduction MTB Statements File System Compiler Applications Reference Guide Index

Overview Creating MTB Source Programs Compiling MTB Programs Compiler Directives Special Characters

UNSET directive

Syntax: UNSET symbolic-constant
Discussion: The UNSET 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 UNSET directive can appear anywhere in an MTB source program.

To facilitate the manipulation of symbolic constants for conditional compilation purposes, the MTB language includes the UNSET directive. The UNSET directive clears the definition of the symbolic constant (i.e., "un-defines" it). This directive is particularly useful when working with the .IFDEF and .IFNDEF directives.

Example:
UNSET ABC     ! un-define the symbolic constant named ABC