Returns the current location associated with a specified
    directory stream. Performs operations on directories.
    Format
      #include  <dirent.h>
      long int telldir  (DIR *dir_pointer);
1 – Argument
 dir_pointer
    A pointer to the DIR structure of an open directory.
2 – Description
    The telldir function returns the current location associated with
    the specified directory stream.
3 – Return Values
    x                  The current location.
    -1                 Indicates an error and is further specified in
                       the global errno.