ByRef param As datatype

[ Declare ] { Sub | Function } proc_name ( ByRef param As datatype )

Passes a variable by reference, that is its address, to a subroutine or function. When a variable is passed by reference, the contents of the variable can be changed by the target subroutine or function.

In -lang qb and -lang fblite dialects, ByRef is the default parameter passing convention, unless Option ByVal is in effect.

Opposite of ByVal.

Dim MyVar As Integer

Sub ChangeVar(ByRef AVar As Integer)
    AVar = AVar + 1
End Sub

MyVar = 1
Print "MyVar: "; MyVar 'output = 1
ChangeVar MyVar
Print "MyVar: "; MyVar 'output = 2
Sleep
End

• In -lang fb dialect, ByVal is the default parameter passing convention for all built-in types except String; String and user-defined Types are passed ByRef by default.
  
• In -lang qb and -lang fblite dialects, ByRef is the default parameter passing convention.
  
  

• New to FreeBASIC
  
  

• Passing Arguments to Procedures
  
• Declare
  
• ByVal