This extremely useful tool allows you to search masses of open source code. It’s nothing new, but I only stumbled upon it the other week and have been using it ever since.

http://www.google.com/codesearch

One of the many cases I find it handy is when I’d like to know how a function is used. For example, search “wxtoolbar(” including quotes to instantly find out how to add a toolbar with wxWidgets. It saves wading through documentation (or lack of it) to learn how to perform simple tasks. You can also enter a string of text describing what you are looking for. Or, if you’re familiar with regular expressions, you can find some very specific code examples.

It’s a must for programmers looking to improve productivity.