Description

   The realpath function returns an absolute pathname from the
   POSIX root. The generated pathname is stored as a null-terminated
   string, up to a maximum of PATH_MAX bytes, in the buffer pointed
   to by resolved_name.

   The realpath function is supported only in POSIX-compliant modes
   (that is, with DECC$POSIX_COMPLIANT_PATHNAMES defined to one of
   the allowed values).

   See also symlink, unlink, readlink, lchown, and lstat.