[AccessD] Can a function return an object?

[John Colby]

 http://www.thevbzone.com/secrets.htm

Interesting and useful for understanding the behind the scenes.  Thanks for
that.

On Sat, Mar 18, 2023 at 12:44 AM Stuart McLachlan <stuart at lexacorp.com.pg>
wrote:

> ChatGPT? <vbg>
> (Actually, don't bother it just told me that
> "OBJPTR is not a built-in function in Visual Basic or VBA. "
>
> Whch is strange, because this works :)
> Function OBJTest() As Long
>     Dim col As Collection
>     Set col = New Collection
>     Debug.Print ObjPtr(col)
> End Function
>
> As for your link. VB.NET?  .net is on a different planet :)
>
> And essentially, the stuff in that link is a load of badly explained
> garbage..
> (Also, you'll' notice that the last "News" update on that site was 2010!)
>
> This seems to be a fairly good reference at first glance:
> http://www.thevbzone.com/secrets.htm
>
>
> On 18 Mar 2023 at 9:17, Borge Hansen wrote:
>
> > Hi Stuart,
> > Interesting information.
> > I am amazed about your level of knowledge.
> > If I wanted to deepen my knowledge about this particular subject, can
> > you give me any pointers / links where I can read more about the
> > STRPTR and VARPTR .... Well - I thought to search Google ... here is
> > one link: https://classicvb.net/tips/varptr/
> >
> > /borge
> >
> > On Sat, 18 Mar 2023 at 07:50, Stuart McLachlan
> > <stuart at lexacorp.com.pg> wrote:
> >
> > > Be careful with the word "pointer".
> > > A pointer "points"  to a memory location.
> > > There is a differentce between a pointer and a reference.
> > > You pass a reference to an object instance , not a pointer.
> > >
> > > An object reference (reference to an object instance) stays  the
> > > same for the life of the instance, but theinstance's location in
> > > memory  may change.   VBA doesn't expose the pointer to it. It's
> > > managed behind the scenes
> > >
> > > It's a bit like the difference between VARPTR and STRPTR for dynamic
> > > strings.The STRPTR will change every time the string is modified so
> > > that it moves in memory, the VARPTR remains the same since it is a
> > > pointer to a pointer to the string.
> > >
> > > In general, all return values are pointers returned in registers
> > > which are de-referenced by the calling statement.
> > >
> > >
> > > On 17 Mar 2023 at 16:13, John Colby wrote:
> > >
> > > > Technically speaking a function returns a *pointer* to an object.
> > > > It is a 32 bit or 64 bit number which points to an address in
> > > > memory where the actual instance of the object resides.  This is
> > > > an important distinction because functions can accept and return
> > > > actual instances of *some* things such as an integer variable.
> > > > But AFAIK objects are never passed, only pointers to objects are
> > > > passed.
> > > >
> > > > IIRC the function is defined with the 'as' keywords after it,
> > > > followed by the type of thing being returned, in this case an
> > > > object of type form.
> > > >
> > > > Function fFrm() As Form
> > > >
> > > >     Set fFrm = Forms("frmLocation")
> > > >
> > > > End Function
> > > >
> > > > Now in the debug window:
> > > >
> > > > ?ffrm.Caption
> > > > frmLocation
> > > >
> > > > On Fri, Mar 17, 2023 at 5:56AM Arthur Fuller
> > > > <fuller.artful at gmail.com> wrote:
> > > >
> > > > > Can a VBA function return an object, such as a form or
> > > > > DAO.database?
> > > > >
> > > > > Can a function return a collection?
> > > > >
> > > > > --
> > > > > Arthur
> > > > > --
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> > > > > Website: http://www.databaseadvisors.com
> > > > >
> > > >
> > > >
> > > > --
> > > > John W. Colby
> > > > Colby Consulting
> > > > --
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> > >
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-- 
John W. Colby
Colby Consulting