SUB (Member)

• Source: https://www.freebasic.net/wiki/wikka.php?wakka=KeyPgMemberSub
• Last revised: 2021-09-28

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Declares or defines a member procedure

Syntax

{ Type | Class | Union } typename

declare [ static | const ] Sub fieldname [calling convention specifier] [ alias external_name ] ( [ parameters ] ) [ Static ]

End { Type | Class | Union }

Sub typename.fieldname ( [ parameters ] ) [ Export ]

statements

End Sub

Parameters

typename

name of the Type, Class, or Union

fieldname

name of the procedure

external_name

name of field as seen when externally linked

parameters

the parameters to be passed to the procedure

calling convention specifier

can be one of: Cdecl, Stdcall or Pascal

Description

Sub members are accessed with Operator . (Member access) or Operator -> (Pointer to member access) to call a member procedure and may optionally accept parameters either byval or byref. typename be overloaded without explicit use of the Overload keyword.

typename is the name of the type for which the Sub method is declared and defined. Name resolution for typename follows the same rules as procedures when used in a Namespace.

A hidden this parameter having the same type as typename is passed to non-static member procedures. this is used to access the fields of the Type, Class, or Union.

To access duplicated symbols defined as global outside the Type, add one or preferably two dot(s) as prefix: .SomeSymbol or preferably ..SomeSymbol (or only ..SomeSymbol if inside a With..End With block).

A Static (Member) may be declared using the Static specifier. A Const (Member) may be declared using the Const specifier.

Examples

start GeSHi

Type Statistics
  count As Single
  sum As Single
  Declare Sub AddValue( ByVal x As Single )
  Declare Sub ShowResults( )
End Type

Sub Statistics.AddValue( ByVal x As Single )
  count += 1
  sum += x
End Sub

Sub Statistics.ShowResults( )
  Print "Number of Values = "; count
  Print "Average          = ";
  If( count > 0 ) Then
    Print sum / count
  Else
    Print "N/A"
  End If
End Sub

Dim stats As Statistics

stats.AddValue 17.5
stats.AddValue 20.1
stats.AddValue 22.3
stats.AddValue 16.9

stats.ShowResults

end GeSHi

Output:

Number of Values =  4
Average          =  19.2

Dialect Differences

• Only available in the -lang fb dialect.

See also

• Class
• Function (Member)
• Sub
• Type

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