Re: passing settings byRef

[BB <adamnt42@xxxxxxxxx>]

On 4/6/26 7:53 am, Karl Reinl wrote:
> Am Mittwoch, dem 03.06.2026 um 22:21 +0100 schrieb Bruce Steers:
> > On Wed, 3 Jun 2026 at 18:05, Karl Reinl <karl.reinl@xxxxxxxxxx 
> > <mailto:karl.reinl@xxxxxxxxxx>> wrote:
> > > Salut Benoît,
> > >
> > > sorry, but I don’t understand the difference between calling
> > > fDialogColor and fDialogFile. Why can settings be passed to fDialogFile
> > > but not to the other two?
> > > (see attached project)
> > > --
> > > Amicalement
> > > Charlie
> >
> > You need to better understand how to use Byref and also when (or not) 
> > you might need it.
> >
> > For starters as the wiki states to use Byref it must be used at both 
> > ends.  Ie, you use ByRef in the class methods as you have in the Run 
> > functions, but you must also use it in the calling command
> >
> > The calling command should look more like this DialogFont.Run(ByRef 
> > Me.cfg, "FIDE", "", True)
> >
> > But i do not think you have to use ByRef at all for your needs here.
> > Passing the Settings object as an argument should work as expected as 
> > you read the object to write to it's members. (I hope that makes sense)
> >
> > Consider this ...
> >
> > Public myNumber As Integer
> > Public myArray As New String[]
> >
> >
> > Public Sub PassVariable(ByRef Writable As Boolean)  ' ByRef is needed 
> > here AND in the calling command.
> >
> > Writable += 10
> >
> > End
> >
> > Public Sub PassObject(Obj As String[])  ' Objects are accessed (read) 
> > and can be manipulated.  only a direct write to the object is not 
> > possible.
> >
> > Obj.Add("A New Item")
> >
> > End
> >
> > Public Sub Main()
> >
> > PassVariable(ByRef myNumber)  ' here ByRef is needed to write the 
> > value back to the myNumber variable. Note "ByRef" is in the calling 
> > command and also in the method
> >
> > PassObject(myArray)  ' As An object myArray can be manipulated 
> > without using ByRef
> >
> > End
> >
> > I think in your program passing a Settings object should not need to 
> > use ByRef.
> >
> > Someone else might be able to explain the exact reason for this 
> > difference and where you do or do not need ByRef.
> >
> > As to why it is only failing with some of your classes i could not 
> > say. sorry.
> >
> > Respects
> > BruceS
>
> Oh, man, that code comes from gambas1, was ported to gambas2 and the 
> to gambas3.
> As the programme is rarely used, the errors may not have been noticed 
> for a year or two. They are always down to changes in Gambas 3 itself; 
> I always use the very latest versions. Thanks for the tip – by 
> omitting the `ByRef`, it’s working again.
> What’s baffling, of course, is that it works sometimes and not others, 
> and that no errors were reported during compilation, not even during 
> the two passes.
>
> --
> Amicalement
> Charlie


I don't think that the compiler knows or even thinks about how the call 
stack is going to be used at runtime. It is only looking at whether it 
can construct a JUMP thingo with a valid parameter stack and whether the 
return stack can be processed (maybe not even that).

b