iPhone Open Application Development

Building the Free Tool Chain

As we discussed in Chapter 1, the iPhone began life as a closed platform. This originally meant that no developer tools were publicly available to build iPhone-native applications. There has been much speculation about whether Apple secretly hoped the community would break into the phone, thus bolstering its status among the geek community. Over the first few months of the iPhone's life, this is exactly what happened. The open source community successfully cracked the phone and began writing a tool chain to build applications. It has since been released as free software. The tool chain consists of a cross-compiler, a linker, an assembler, a C hook into the assembler called Csu, and class headers for Objective-C frameworks generated by a tool called class-dump.

The tool chain uses a cross-compiler, which is a compiler that runs on one machine (namely, your desktop) but builds executables that can run on a different machine (the arm processor in an iPhone). The commands and path names provided throughout this book presume that you've used the procedures from this chapter to build and install the tool chain. The tool chain is updated periodically as new versions of it are released, so its setup can sometimes change. The instructions here will guide you through the steps to install version 0.30 of the tool chain, which is the latest available at the time of this writing. Newer versions are documented on the official tool chain project page at http://code.google.com/p/iphone-dev ...