xcodebuild doesn't output warnings & errors?

I'm running xcodebuild, but the command line isn't outputting source code warnings and errors. It just says CompileC failed. How do I get xcodebuild to output 开发者_JAVA百科source code level warnings and errors?

The problem is often that an error has occurred higher up the stack, but then the message is completely missing by the time that Xcode prints out the error message. Try running:

xcodebuild | grep error

and it often gives more helpful advice than before.