Programming Reference Manual
 
Syntax
 
Option Base [0|1]
-or-
Option Compare [Binary | Text]
-or-
Option Explicit
-or-
Option Private Module
 
Description
Form 1: Set the default base index for array declarations. Affects Dim, Static, Private, Public and ReDim. Does not affect Array, ParamArray or arrays declare in a Type. Option Base 0 is the default.
 
Form 2: Set the default comparison mode for string.
•   Option Compare Binary - compare string text using binary data (default)
•   Option Compare Text - compare string text using the collation rules
String comparision using <, <=, =, >, >=, <>, Like and StrComp are affected by this mode's setting.
 
Form 3: Require all variables to be declared prior to use. Variables are declared using Dim, Private, Public, Static or as a parameter of Sub, Function or Property blocks.
 
Form 4: Public symbols defined by the module are only accessible from the same project.
See Also
 
Example
 
Option Base 1
Option Explicit
 
Sub Main
    Dim A
        Dim C(2) ' same as Dim C(1 To 2)
        Dim D(0 To 2)
    A = 1
    B = 2 ' B has not been declared
End Sub