Option Definition

Syntax:

Option Base [0|1]

-or-

Option Compare [Binary | Text]

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Option Explicit

-or-

Option Private 
 Module

Group:Declaration

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 comparison 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.

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
EndSub