Recursive vs. CallBack

[Shark]

What is the difference with "recursive" function and "callback" function?

A recursive function is one that calls itself eg:

Public Function foo(arg as Variant)
    'do some stuff (like the exit case)
    foo(arg)
Next Function

It has no reference point ot the function that called it.

On the other hand a call back function knows which function called it, and can talk back to that function (its a bit of a theoretical concept, and I can't provde a decnt sample)

- gaffa

[Joacim Andersson]

Just like gaffa said a recursive function calls itself. The most usual example is a function that count the faculty of a number:

Public Function Faculty(Number As Integer) As Long
    'The facutly of 1 or 0 is 1
    'so that's the exit point
    If Number = 1 Or Number = 0 Then
        Faculty = 1
        Exit Function
    End If
    Faculty = Number * Faculty(Number - 1)
End Function

A call back function is when you pass a pointer to a function as an argument to an other function.
The function you call in turn calls the function you pass as an argument.
A lot of API functions use callback functions. A few of them is:[*]EnumWindows[*]EnumChildWindows[*]EnumTimeFormats[*]EnumClipboardFormats[*]...and so on...

Before VB5 you couldn't use any of these functions because VB didn't have a way for passing a function pointer.
But Microsoft introduced the AddressOf keyword in VB5.

Best regards