Xcode4 Linking Problem. File was built for archive which is not the architecture being linked (arm6)

Question

Recently, I switched to Xcode4 and when I compile my project I got following error.

ld: warning: ignoring file /Users/myname/Library/Developer/Xcode/DerivedD         


        

Answer 1

If I get the ignore file warning - I would run lipo -info on ignored file to find it's architecture as below

lipo -info libTapkuLibrary.a

That would print either of i386, armv6, armv7, armv7s, x86_64 etc. In general, that architecture has to match with your target build platform. E.g.

• i386 = ios simulator or 32 bit build on mac os x
• armv6 armv7 arm7s = ios device
• x86_64 = 64 bit build on mac os x

Depending on the mismatch, either you have to rebuild your library for your target platform or change your target platform.

Note: For fat binaries, lipo -info will print a combination of above architectures.