ActiveX and RR
chipp at chipp.com
Mon Aug 9 18:07:30 CDT 2004
Dar Scott wrote:
> Many automation COM services do not need a control. I realize that most
> folks want the control, but where I could have used this over the past
> couple years, I have not needed the control.
I agree, this actually would be the best case scenario for an
ActiveX/COM wrapper external.
> The calls should be more straightforward. The callbacks may be a
> problem and there may be a need to get across a thread boundary. In
> looking at similar problems, I think the Revolution app may need to poll
> for the callbacks.
You are correct, this is the big hurdle.
> I don't think this is as bad as it sounds. The first step is to come up
> with the right mapping of types. The pointers are known and are not
> arbitrary so a scheme can be set up for those. The implementation step
> might be tedious but half can be done in transcript.
Certainly a naming convention could be setup where variable prefixes in
RR could be used to 'type' data on the other side. But, even then,
pointers referring to pointers still remains a problem... And arrays,
too (Arrays of arrays of arrays...I know I know...'Dar's Boxes!' :-)
> Such a thing would have been handy for some DCOM work over the past
> couple years, but I don't know how much that might come up again. I
> have toyed with the idea of a generic dll interface, but that has crash
> risks if the developer gets the interface wrong.
No doubt, making a crash proof version would be a challenge. In fact, a
main reason we haven't taken this on is primarily one of support.
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