> If you don't mind me asking:

> Is there a way to have one instance of a COM object to be used by multiple
> machines/applications? (dcom?)

> My programming environments are Borland Delphi 4 (and VB6)

> Erik Tamminga
> etammi...@starren.nl

> Do you really mean can you create a singleton COM object?  If so then the
> answer is yes, although how you achieve this in the Delphi framework is
> questionable.   It is recommended (esp for DCOM implementation) to create
> multiple object instances, but each instance uses the same object data.
> This allows for load-balancing, better garbage collection etc.

> The long and short of it is that yes you can create a singleton - how you
do
> it is down to one of two means:

> 1. Override IClassFactory to return the same instance pointer (*not so
good)
> 2. Implement multiple objects using the same data

> *If you override CreateInstance in the IClassFactory, to return the same
> instance pointer, then you will be violating the laws of COM - the
semantics
> of the of interface (the contract) is violated, since the user expects
> CreateInstance to create a new instance, all the time.

> Nick.

> Erik Tamminga <etammi...@starren.nl> wrote in message
> news:7umkar$s6n2@forums.borland.com...
> > Hello,

> > If you don't mind me asking:

> > Is there a way to have one instance of a COM object to be used by
multiple
> > machines/applications? (dcom?)

> > My programming environments are Borland Delphi 4 (and VB6)

> > Erik Tamminga
> > etammi...@starren.nl

> When using word, you can say:

>     // Create a word object
>     Word := CoApplication.Create;
>     Word.Visible := True

> and later on for example in a VB Application say

>     Set Word = GetObject(, "Word.Application")
>     Word.Visible = False

> This returns a pointer to the same instance of word as created in the
first
> application. The first app displays word, the second app hides word.

> Erik

> Nicholas Robinson <NicholasRobin...@yahoo.co.uk> wrote in message
> news:7umm22$s713@forums.borland.com...
> > Hi Erik,

> > Do you really mean can you create a singleton COM object?  If so then
the
> > answer is yes, although how you achieve this in the Delphi framework is
> > questionable.   It is recommended (esp for DCOM implementation) to
create
> > multiple object instances, but each instance uses the same object data.
> > This allows for load-balancing, better garbage collection etc.

> > The long and short of it is that yes you can create a singleton - how
you
> do
> > it is down to one of two means:

> > 1. Override IClassFactory to return the same instance pointer (*not so
> good)
> > 2. Implement multiple objects using the same data

> > *If you override CreateInstance in the IClassFactory, to return the same
> > instance pointer, then you will be violating the laws of COM - the
> semantics
> > of the of interface (the contract) is violated, since the user expects
> > CreateInstance to create a new instance, all the time.

> > Nick.

> > Erik Tamminga <etammi...@starren.nl> wrote in message
> > news:7umkar$s6n2@forums.borland.com...
> > > Hello,

> > > If you don't mind me asking:

> > > Is there a way to have one instance of a COM object to be used by
> multiple
> > > machines/applications? (dcom?)

> > > My programming environments are Borland Delphi 4 (and VB6)

> > > Erik Tamminga
> > > etammi...@starren.nl