Description

   The rewinddir function resets the position of the specified
   directory stream to the beginning of the directory. It also
   causes the directory stream to refer to the current state of the
   corresponding directory, the same as using the opendir function.
   If the dir_pointer argument does not refer to a directory stream,
   the effect is undefined.

   The type DIR, defined in the <dirent.h> header file, represents
   a directory stream. A directory stream is an ordered sequence of
   all the directory entries in a particular directory. Directory
   entries represent files.

   See also opendir.