where should I download the core foundation library? I have a program that includes CoreFoundation/CoreFoundation.h ... It is an iPhone app, but I'm thinking the core foundation code will run on linux.
All Apple's open source code can be found in http://opensource.apple.com/. The source code of Core Foundation (actually, "CFLite") can be found in https://github.com/apple-oss-distributions/CF/tree/CF-635.19, and can be downloaded from http://www.opensource.apple.com/tarballs/CF/CF-635.19.tar.gz.
The README file describes how to build the library on Linux. Note that not the full Core Foundation is available.
The Mac OS X version of CFLite supports most of the functionality of the full CoreFoundation. The Linux version of CFLite focuses on strings, dates, collections, and other property-list related items.