Unable To Generate TUs With PCH Files

Hello everyone,

I'm not able to generate a TU using clang_parseTranslationUnit, with a PCH
file, that is located on disk. Does anybody know what I am missing?
These are the command line option arguments that I'm passing to
clang_parseTranslationUnit:
-include-pch <path-to-pch-file>
-arch i386-pc-win32
-Xclang
-ccc-host-triple i386-pc-win32
clang_parseTranslationUnit returns an empty TU.

Thank you!