Function CheckStyle

Checks rules from the 'C++ style rules' section of cppguide.html. Most of these rules are hard to test (naming, comment style), but we do what we can. In particular we check for 2-space indents, line lengths, tab usage, spaces inside code, etc. Args: filename: The name of the current

(filename, clean_lines, linenum, file_extension, nesting_state,
               error)