See L</seek> for some details about mixing reading and writing.
+=item opendir DIRHANDLE,MODE,EXPR
+
=item opendir DIRHANDLE,EXPR
Opens a directory named EXPR for processing by C<readdir>, C<telldir>,
C<seekdir>, C<rewinddir>, and C<closedir>. Returns true if successful.
DIRHANDLEs have their own namespace separate from FILEHANDLEs.
+In three-argument form the middle argument may be C<:utf8> to force
+the filenames returned by readdir() to be in UTF-8 encoding of Unicode.
+This naturally works only if your filesystem returns UTF-8 filenames.
+
=item ord EXPR
=item ord
@dots = grep { /^\./ && -f "$some_dir/$_" } readdir(DIR);
closedir DIR;
+In some filesystems it is possible to return UTF-8 encoded filenames.
+To get readdir() to return such filenames, you must use C<:utf8> with
+the three-argument form of opendir(), see L</opendir>.
+
=item readline EXPR
Reads from the filehandle whose typeglob is contained in EXPR. In scalar