Print clang include path and store in file

I'm writing a program that needs to pull in the clang include paths. Thanks to Dump include paths from g++ I'm half-way there. The command I'm using is: clang++ -E -x c++ - -v stdout.txt clang++ -E -x c++ - -v stderr.txt So where is the output being redirected to and what command do I need to execute to properly store off the information that is printed to console?