I want to learn COM. How should I proceed?

Question

Hello Guys,

I am a fresh graduate with a bachelor in Computer Science. As most school today, they are no longer teaching students C or advance C++ (only an Introductory course in C++... With lessons up to Pointers). The standard programming language prescribed in the curriculum is C# (.NET stack).

Just recently, I got hired as a junior software developer. 95% of our codebase is in C++ and our products are using COM/DCOM. The other 5% is in .NET. My current responsibility is to maintain a project written in .NET (ASP.NET) and I am not required to study C++ and other technology YET. But I want to learn COM as soon as possible so I can help out on other projects.

So I am seeking the advice of this community on how I can go about learning COM. My current questions are the following:

1. Any required reading? (Pre-requisite topics)
2. A Good Site in Learning the basics of COM?
3. A type of Simple Program to really appreciate the "purpose" of COM (A chat program perhaps?)

Thanks! :)

PS: Should I mark this as a community wiki?

Answer 1

The book of Don Box about COM is the definitive reference. Amazon link.

Beware is a tough read, but it covers everything in deep. And remember, as Don said... COM IS LOVE.

I do not believe you can find a lot of web site, COM was a up to date technology a lot of time ago, but if you can forgot about it trust me... it's better!

Answer 2

I would recommend the book ATL Internals, it may be getting a bit old but it will teach you the basic fundamentals of COM. As the tho poster commented, the Don Box is good as well.

Answer 3

It's obvious, but have you visited microsoft site for COM? That's how I started, later I just googled for info when I stuck at something (which was a lot, COM's nasty at some points). I also asked a lot my co-workers, nothing's better than face-to-face explanation on some voodoo you can see in code

Answer 4

Read the Don Box book for all you could ever want to know (and forget) about COM.

As for the purpose of COM: Whereas C++ gives you (source) code reuse, COM gives you (compiled) component reuse.

Answer 5

To learn the very basic ideas behind COM, I've never come across anything better than Inside COM by Dale Rogerson. This is an old book, but it explains very clearly why COM is needed and how it is implemented, and you can pick up a second hand copy on Amazon.

As for the Don Box books, I've read all of them and I think they are pretty damn poor. Box neverr explains the motivation for the code he descrribes and uses deeply unrealistic examples. But I realise this is a minority opinion.

Answer 6

I have in my library these books on COM which I'd recommend:

1. 1995 - Kraig Brockschmidt - Inside OLE 2nd Edition
2. 1998 - Don Box - Essential COM
3. 1999 - George Shepherd - Inside ATL
4. 2000 - Andrew Troelsen - Developer's Workshop to COM and ATL 3.0
5. 2006 - Christopher Tavares - ATL Internals : Working with ATL 8, 2nd Edition

and if you say you have some .net background there's the

1. 2003 - Julian Templeman - COM Programming with Microsoft .NET

Hope this helps.

Answer 7

Some classic books already mentioned here. I'll also throw in Designing Component-Based Applications by Mary Kirtland.

It is old (as most titles mentioned are), and is mainly aimed at Enterprise developers. It has a nice overview of COM without getting too deep in the weeds, talks about 3-tier development, discusses MTS (the book predates COM+) and its uses. It also talks about designing data and business components and walks through developing a sample application.

I'm not sure how well it has aged but I remember 10 years ago it was a great introduction to the world of COM. The strength of the book is that it assumes that you know nothing about the topic. It nicely balances theory with practical implementations in a logical progression. I think there is some ASP (classic) in there too...so for the love of all that is holy skip that part. :)

I remember that Dr. GUI had some great COM articles (e.g. Dr. GUI's Gentle Guide to COM) but was unable to track them down.