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From: William E. Kempf (wekempf_at_[hidden])
Date: 2003-04-24 13:09:36

Noel Yap said:
> "Justin M. Lewis" wrote:
>> in/out seems to be used fairly commonly in COM. I'm not sure I have
>> any great examples off the top of my head, but I know they're commonly
>> used.
> I'm not a COM person, but I believe it's written in C. If so, then you
> are correct that in/out parameters are more needed since noone would
> want to create a struct for each multiple return type.

COM can be coded in any language. In COM, as in every RPC mechanism I
have experience with, in/out attributes are used to optimize how things
are wired (or not). That they might also be meaningful to someone
reading/maintaining the code is just a side effect.

> OTOH, C++ has templates to deal with this situation (ie boost::tuple<>)
> so, qualifying my previous statement, in C++ I still see no need for
> in/out parameters.

Same reason as with RPC... though all it really would do is make the
compilers job easier in optimizing code. (Note that I'm not advocating
the usage.)

William E. Kempf

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