Cannot compile a static library for arch armv7

Question

I have a static library (very simple, no includes) which builds fine with "-arch i386", I can use the demo method in this library and everything is fine. As usual I have an .a file to link in my project.

Unfortunately I want to use this library in an iOS project, so when I use the iPhone Simulator everything is fine with the library built with "-arch i386" (because this is the processor the simulator uses). If I now want to build the library with "-arch armv7" (or "-arch armv6") for my ARM-based iPhone device I get in Eclipse and in Xcode the same error message: (in Xcode:) llvm-gcc-4.2 failed with exit code 255 . Same exit code in Eclipse (255). With "i386" everything works.

Must I install anything in addition to my Xcode 4.2.1 on OSX Lion to make compile the lib for my ARM-Device?

Answer 1

The issue lies in the fact that Xcode 4 builds static libraries for each build rather than one unified universal build. So my guess is that you are just adding the build for debug-simulator and not for debug-device. Your best bet, add a script to your static library to build them all into one.

This post here on SO saved my life. Hopefully it will help you too.