Option Explicit
Forces explicit declaration of all variables.
The Option explicit statement is used outside of the script in the declarations section. This statement can be contained in a declare file or outside of any script in a file or buffer. If this statement is contained in the middle of a file the rest of the compile buffer will be affected.
Related Topics: Const and Global Statements
Example :
Option Explicit
Sub Main
Print y ‘because y is not explicitly dimmed an error will occur.
End Sub