Overridesub

Method attribute; specifies that a method must override a virtual

Syntax

Type typename Extends basename

...

Declare Sub|Function|Operator|Property|Destructor ... ( [parameterlist] ) [[ ByRef ] As datatype] Override

...

End Type

Description

In method declarations, Override can be used to indicate that this method is expected to override a Virtual or Abstract method from the base class. Then the compiler will show an error if the method does not override anything (only a non-static method can override a virtual or abstract method).

Use of Override is not mandatory to override a virtual or abstract method, it is highly recommended, as it will help prevent inadvertent errors (name/signature not matching).

Override can only be specified on the method declaration in the UDT block, but not on the method body, because it is just a compile-time check in the context of the inheritance hierarchy, and does not affect the method in any way.

Override is only recognized as a keyword at the end of member procedure declarations. It can still be used as identifier elsewhere.

Remarks

Differences from QB

• New to FreeBASIC
  
  

See also

• Virtual, Abstract
  
  

Example

Type A Extends Object

    Declare Virtual Sub f1( )

    Declare Virtual Function f2( ) As Integer

End Type



Type B Extends A

    Declare Sub f1( ) Override

    Declare Function f2( ) As Integer Override

End Type



Sub A.f1( )

End Sub



Function A.f2( ) As Integer

    Function = 0

End Function



Sub B.f1( )

End Sub



Function B.f2( ) As Integer

    Function = 0

End Function

Reference

• Documented in KeyPgOverride.html