🚀 go-pugleaf

Colin B Maharaj wrote:

> Now, is there some way that I can then call this code , which I want
> to put in a DLL and instantiate multiple instances of the classes in
> the DLL.

Yes but importing/exporting object instances is proprietary and
language specific. You will not find it easy to import a Borland object
from a VC application. Should you or someone else ever need to use
those classes from a different language it will probably be nigh-on
impossible.

Generally accepted wisdom is to provide handle based access to classes
across DLL boundaries. The handle can either be a subscript into an
array of objects or the pointer to the object instance casted to 'void
*'.

Example 1:Easier to spot invalid handles.
// DLL code
int DLL_Exported_Wibbler( int objectHandle )
{
  return MyObjectList[ objectHandle ]->Wibble();
}

Example 2:Slightly faster than using an array/vector
// DLL code
int DLL_Exported_Wibbler( void * objectHandle )
{
  return reinterpret_cast<TMyObject *>( objectHandle )->Wibble();
}

-- 
Andrue Cope [TeamB]
[Bicester, Uk]
http://info.borland.com/newsgroups/guide.html