Despite the widespread availability of POSIX operating systems, writing C code that is portable to a wide variety of Unix operating systems is still a challenging problem, even for an experienced developer. Add in the need to run on Windows, Netware, OS/2, and even BeOS and you've got something that's beyond all but the most operating system agnostic among us. But all is not lost for the cross platform C programmer, you can make the task manageable simply by building on the right foundation, the Apache Portable Runtime. The Apache HTTPD runs on all of these platforms, and the collective knowledge of the developers that made that possible has been condensed into a C level API that lets you portably take advantage of the best platform specific abilities on each system, while still remaining portable enough to run without them. Learn how to portably go from "Hello World" all the way up through a multithreaded network server, gaining a working knowledge of APR's API via complete examples who's lessons you can easily use in your own applications.