COMMON


Variable declaration and scope modifier

Syntax:
Common [Shared] symbolname[()] [AS DataType] [, ...]

Description:
Declares a variable which is shared between code modules. A matching Common statement must appear in all other code modules using the variable.

Common variables cannot be initialized.
Common arrays are always variable-length, and must be defined with an empty parameter list (), and its dimensions set in a later Dim or Redim statement.
Common variables cannot be instances of a user-defined type having a constructor or a destructor even implicit.

The Shared optional parameter makes the variable global so that it can be used inside subs and functions, as well as at module level.

Examples:
'' common1.bas

Declare Sub initme()

Common Shared foo() As Double

ReDim foo(0 To 2) As Double

initme()

Print foo(0), foo(1), foo(2)


'' common2.bas

Common Shared foo() As Double

Sub initme()
  foo(0) = 4*Atn(1)
  foo(1) = foo(0)/3
  foo(2) = foo(1)*2
End Sub

Output:
 3.141592653589793           1.047197551196598           2.094395102393195


Differences from QB:
See also:
Back to Modularizing
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