[Gambas-user] Callback

[tommyline at ...2340...]

I was experimenting with the code and simply this works :

Public sub main()
  calll(twotimes(3))
end

Public Sub twotimes(a As Integer) As Integer
  Print a
  a *= 2
  Print a
  Return a  
End

Public Sub calll(cb As Pointer)
  
  Print "should be printed twice"
  
End

output:

3
6
should be printed twice

External function using callback works fine too:

in freeglut_std.h:
glutDisplayFunc( void (* callback)( void ) );


in Gambas:

Public Extern glutDisplayFunc(callback As Pointer)

call simply:

glutDisplayFunc(screen_draw)

when

public sub screen_draw()
...
end


Tomek.
----- Original Message -----
From: "tobias" <tobiasboe1 at ...20...>
To: "mailing list for gambas users" <gambas-user at lists.sourceforge.net>
Sent: Thursday, 11 August, 2011 9:41:05 PM
Subject: Re: [Gambas-user] Callback

hi,

> Or, see code:
>
> To class named "Twotimes":
>
> Static Public Function _call(x As Integer) As Integer
>    Return x * 2
> End
>
>
> Then somewhere else:
>
> ''This is the function that accepts callbacks.
> Public Function testing(x As Integer, ofunc As Object) As Integer
>   Return ofunc(x)
> End
>
>
> ''Here is how to call it.
> Dim ChosenFunction As Object
>
> ChosenFunction = New Twotimes ''Here you can set the callback function.
> Print testing(2, ChosenFunction)
>
>
> Jussi
  this is a very pretty workaround. i'll use that!
thanks

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