Igor Tandetnik wrote:
PaulH <paul.heil@gmail.com> wrote:
I have an ATL COM dll that, in some cases, I would prefer to access
the methods of as if it were a C dll with an exported function to get
access to CMyClass() as below.
Is this even possible?
It is possible, but it's very rarely a good idea. One of the points of
COM is that you can change your implementation later, but still preserve
binary compatibility with existing clients. If you expose your C++ class
directly, every time you change anything in it you would have to rebuild
all clients.
MyClass.h is auto-generated by visual studio,
how do I add a GetClass() method to it?
By opening the file in your favorite text editor and typing the code in,
of course. Programmers are known to do this at times.
Note that it doesn't have to go into the same source file, if for some
reason you would prefer to keep it separate.
--
With best wishes,
Igor Tandetnik
With sufficient thrust, pigs fly just fine. However, this is not
necessarily a good idea. It is hard to be sure where they are going to
land, and it could be dangerous sitting under them as they fly
overhead. -- RFC 1925
Okay, but CMyClass uses the BEGIN_COM_MAP() and END_COM_MAP() macros
which contain virtual functions, so I end up with:
.\MyAPI.cpp(88) : error C2259: 'CMyClass' : cannot instantiate abstract
class
due to following members:
'HRESULT CMyClass::QueryInterface(const IID &,void **) throw()'
: is abstract
MyClass.h(118) : see declaration of 'CMyClass::QueryInterface'
'ULONG CMyClass::AddRef(void) throw()' : is abstract
MyClass.h(118) : see declaration of 'CMyClass::AddRef'
'ULONG CMyClass::Release(void) throw()' : is abstract
MyClass.h(118) : see declaration of 'CMyClass::Release'
'HRESULT CMyClass::QueryInterface(const IID &,void **) throw()'
: is abstract
MyClass.h(118) : see declaration of 'CMyClass::QueryInterface'
'ULONG CMyClass::AddRef(void) throw()' : is abstract
MyClass.h(118) : see declaration of 'CMyClass::AddRef'
'ULONG CMyClass::Release(void) throw()' : is abstract
MyClass.h(118) : see declaration of 'CMyClass::Release'
What do I do with all of these?
-PaulH