\brief Retrieve a file handle within the given translation unit.
\param tu the translation unit
\param file_name the name of the file.
\returns the file handle for the named file in the translation unit \p tu, or a NULL file handle if the file was not a part of this translation unit.
See Implementation
\brief Retrieve a file handle within the given translation unit.
\param tu the translation unit
\param file_name the name of the file.
\returns the file handle for the named file in the translation unit \p tu, or a NULL file handle if the file was not a part of this translation unit.