C++ Error Handling -- Good Sources of Example Code?

Just about every piece of example code everywhere omits error handling (because it "confuses the issue" that the example code is addressing). My programming knowledge comes primarily from books and web sites, and you seldom see any error handling in use at all there, let alone good stuff.

Where are some places to see good examples of C++ error handling code? Specific books, specific open-source projects (preferably with the files and functions to look at), and specific web pages or sites will all be gratefully accepted.