ProblemSolution

Common issues you may encounter and their solutions.

NSConcreteStackBlock

Your application fails to launch, and you see a crash message that looks something like

Dyld Error Message: Symbol not found: **NSConcreteStackBlock

This seems to be an issue with LLVM, and blocks in general. It seems to affect those using Xcode 3, and targeting either Mac OS X 10.5 or iOS 3.X, and perhaps using the LLVM compiler.

A solution was posted to StackOverflow, and states that you should specify the linker flag

-weak_library /usr/lib/libSystem.B.dylib

This was also reported in Issue #10 (concerning Mac OS X 10.5), and the linker flag was reported to work.