Hmmm. Well, in this case:

#1: My code contains zero classes (yes, it is C++, but more like C code written in C++ to take advantage of a few minor syntax conveniences). Also, I do not #include any object-oriented libraries. The only external libraries I include are standard C libraries (not C++ libraries), xlib (XWindows lowest level library), GLX (part of XWindows to support efficient OpenGL).

#2: My code compiled and ran before I upgraded to the new Java and made sure everything was configured correctly with galternatives. This problem appeared after doing the above, with zero lines of my code changed. I also re-installed / upgraded a couple core packages that you (or one of the other software packages) told me to. I think those were called "build-essential" and "lib32".

I'm not sure what you mean by "the way your files are organized in /usr/include". None of my files are in directory "/usr/include/". All my files are in "/home/max/workspace/ice" and "/home/max/workspace/ig" (the main project directory).

So I'm thinking something about the new configuration or updated packages is probably the cause. I just have no idea what. Any ideas?

what no emacs?
you can't talk about IDEs without mentioning emacs

I can't really see how upgrading java could get in the way of a c++ project as all it does it drive the GUI. It seems more likely that upgrading build-essential has something to do with it. Maybe it installed a different c++ compiler (g++)?

By the way, have you checked project > Properties? If g++ was upgraded, it may have changed one or more settings.

Yup, the project properties look the same as they were. Also, I doubt a new g++ compiler could change the property settings stored inside a project managed by eclipse!

No, it wouldn't but I was referring to system settings/variables. Still, this is such a strange case that I don't know what to think. Have you tried switching galternatives back to gcj? That would place you back where you started out from but at least it would show whether it is the java upgrade that is to blame or not.

I changed them all back, but it made no obvious difference. So I changed them back to the more recent release again. Still no difference. Unfortunately, it appears I will need to completely reinstall everything from scratch again, probably including ubuntu (just to be safe). Unfortunately, I don't think I wrote down every step that I've taken - though at least the ideas on this forum are still here to refer to. Sigh. I so need to return to developing my application! Boo hoo, but that's life. Oh, I created a new small, barely larger than "hello world" project that includes the <time.h> file - and it doesn't work either. That's what convinced me it is time for serious action (as in clean install of everything). BackToTheFuture IV.