Another thing to know about is the directory_options enum class. The constructor of recursive_directory_iterator does indeed accept a value of this type as a second argument. The default value which we have been implicitly using is directory_options::none. The other values are:

• follow_directory_symlink: This allows the recursive iterator to follow symbolic links to directories
• skip_permission_denied: This tells the iterator to skip directories that would otherwise result in errors because permission to access is denied by the filesystem

These options can be combined with the | operator.