Releasing source code snippets created by others under the GPL

With the open source licenses in general... and the GPL in particular, you can't assume you have permission to incorporate a piece of code if you don't know specifically how it is licensed. There are some GPL compatible free software licenses like Modified BSD (sans copyright notice requirement), X11, Python, Zope, Public Domain (no copyright), etc. There are some GPL-Incompatible Free software licenses like the original BSD license, Apache, Mozilla Public License, PHP, etc. There are also Non-Free licenses like Sun's Community License, Qmail, PINE, Microsoft's Share Source licenses, etc.

The general rule of thumb is to assume you can not incorporate the code into a GPLed project unless you specifically know that you can. You know you can if it is using one of the GPL-compatible licenses above. You also know you can if the author specifically releases all their code into the public domain (hence no copyright). In other cases, you should get specific permission from the copyright holder and make sure that they are, in fact, the copyright holder to all the code in their project (or that they have permission from all said holders). Sometimes, some "free" applications out there are using code bits taken from other sites with questionable licenses/copyrights. (Side note: In emailing El Salvador, the creator of ASuite, we discovered one of the code libraries he was using was GPL-incompatible, but he contacted the author and got permission for it to be GPLed... so it can work out).

As for the Microsoft example code, I recall from when, in years past (back in my former life working corporate), that the example code with many of Microsoft's products was licensed in a way that permitted commercial use, company use and personal use provided you adhered to certain restrictions. I also remember that many code snippets released carried a license that prohibited their inclusion in a product that competed with a Microsoft product (like Word, for example) which I always found particularly distasteful... I can understand it from a company/business perspective... but this is them putting limitations on what someone can do with Microsoft's development tools. I can't locate a license specifically for the example code in the knowledge base anywhere (and I've been looking for a while), but of the other source code licenses I've found, it doesn't look good: gotdotnet.com sample code license, asp.net sample code license, Microsoft Permissive License (Microsoft's most open license) and their other shared source licenses. Now, from my own completely un-lawyerly reading of these (i am not a lawyer, etc etc), none of them are GPL-compatible. None are even BSD-compatible. Basically, unless you can find out what the licensing terms are for the code in the Microsoft Knowledgebase, you can't relicense it under the GPL. If you want to use it in a GPLed project, you'll need to ask Microsoft. Unless someone else can find a definitve URL that tells us all what the license is.

Believe me, I wanted to use the code to eject under Windows NT/2000/XP and eject under Windows 95/98/Me, too. But without knowing the license, we can't.

Also, I double-checked the code project, and their rules from the FAQ are as follows:

Can I use code snippets and programs in my own work?

Some authors may also have specific restrictions on using code in commercial apps such as providing credit in documentation or sending them an email first.

As you mentioned, that first bit about notices appears to be fine (the GPL require proper attribution). And the third bit about no implied or express warranty would also appear to be ok, too (Sections 11 and 12 of the GPL have a solid no warranty clause). But that second bit about not selling or republishing would appear to be an issue. GPLed code can be freely published and the resulting binaries can be sold. BSDed code can be freely published and sold as well. Thus, I don't think you can release anything you've gotten from The Code Project as open source without permission from the copyright holder. Hopefully, it will be as simple as asking the author you mentioned, Uwe Sieber, and him saying OK. Give it a shot... it worked out for ASuite.