code: def search_filename(fname, lineno, local_first):
      
      fname = api.utils.sanitize_filename(fname)
      i_path = [CURRENT_DIR] + INCLUDEPATH if local_first else list(INCLUDEPATH)
      i_path.extend(OPTIONS.include_path.value.split(':') if OPTIONS.include_path.value else [])
      if os.path.isabs(fname):
          if os.path.isfile(fname):
              return fname
      else:
          for dir_ in i_path:
              path = api.utils.sanitize_filename(os.path.join(dir_, fname))
              if os.path.exists(path):
                  return path
  
      error(lineno, "file '%s' not found" % fname)
      return ''
docs: Search a filename into the list of the include path.
      If local_first is true, it will try first in the current directory of
      the file being analyzed.