Re: [Swig-user] GSoC - COM module

[Jan J. <je...@po...>]

David Piepgrass wrote:
> Hi, I would like to start using the COM module. How can I get a Windows
> swig.exe that wraps to COM?
> 
> Thanks for making it, Jan! I'm sure it will be very useful to me!
> 
> By the way, since I am new to COM, can someone suggest a primer? And
> what does one need to know in order to pass strings, floating-point, and
> small structures (e.g. X,Y,Z points) between C++ and the COM interface?
> 
> 
> -------------------------------------------------------------------------
> This SF.Net email is sponsored by the Moblin Your Move Developer's challenge
> Build the coolest Linux based applications with Moblin SDK & win great prizes
> Grand prize is a trip for two to an Open Source event anywhere in the world
> http://moblin-contest.org/redirect.php?banner_id=100&url=/

Hi David,

Sorry for the late response. There is no official build containing the 
SWIG COM module yet. I have prepared a snapshot build of revision
10893, in case that you want to give it a quick try. It is available here:
http://tcs.uj.edu.pl/~jezabek/swig-com-r10893.zip
Unfortunately it needs to be unpacked to c:\program files\swig, and
the path is hardcoded at configure time. If this path is unacceptable to 
you then just drop me a note and I'll prepare another build (takes just 
a few minutes).
The build is unofficial, but it should be pretty stable and feature 
complete.

Regarding your other questions - if you use SWIG then you do not need to 
do anything special to handle strings and FP types. The string types are 
converted to BSTR - which is de facto standard in COM, and required for 
VB interoperability. FP types (float and double) are supported by COM 
and should work without problems.
For structures - currently they are treated just like classes, so you 
get a getter/setter for each member. There is no support yet for 
treating them as 'value-types' (as one would say in C#), although it is 
one of my future goals. Still with the current approach you can 
manipulate structures in a natural way from languages supporting 
properties (VB, Delphi, probably many more).

I know no primer on COM that I could recommend - all that I know about 
COM comes from various info picked up here and there in the last few 
years. I found the reference at MSDN quite useful, but as its name says 
it is more a reference than an introduction. It is available here:
http://msdn.microsoft.com/en-us/library/ms680573(VS.85).aspx
There is also an article that seems to be a general introduction to COM. 
I haven't read it, but maybe you'll find something interesting there:
http://msdn.microsoft.com/en-us/library/ms877981.aspx

Feel free to follow up with any questions you might have.

Thanks,
Jan Jezabek

-- 
My GSoC 2008 development blog: http://jezabekgsoc.wordpress.com/