I've tossed everything else into this blog, why not a little C++ code? Here's a routine for locking files in C++. I couldn't find a good example on the web, so perhaps this will be of use to someone. This code has been tested on Linux. For Windows, you'll have to do something different, using _sopen I think.

Update, September 2005: This code has proved so popular in my weblog stats, that I have moved it to a new page on my site for especially for C++ code. I hope to add more code later.