If you’re having problems with Xcode not intercepting console/terminal output from your program (with ⌘-R, Build and Run or ⌘-Y, Build and Debug), try this:

• Go to your Xcode project and select the executable in the project list.
• Bring up the inspector for the executable (⌘-I, or just double-click on it).
• Change “Use Pseudo terminal for standard input/output” to “Use Pipe for standard input/output” on the General tab of the inspector.
• Do not use a Pipe for standard input/output on the Debugging tab of the inspector, unless you don’t want to be able to debug your executable.

That fixed it up for me.