=head3 new ($filename, $dict [,%opts])
Creates a new system file from the dictionary C<dict>. The file will
-be written to the file called C<filename>.
+be written to the file called C<filename>. The string C<filename> must
+be encoded in UTF-8.
C<opt>, if specified, is a hash containing optional parameters for the
system file. Currently, the only supported parameter is
C<compress>. If C<compress> is non zero, then the system file written
Open is used to read data from an existing system file.
It creates and returns a PSPP::Reader object which can be used to read
-data and dictionary information from C<filename>.
+data and dictionary information from C<filename>. The string C<filename>
+must be in UTF-8 encoding.
+
+=head3 get_case_cnt ()
+
+Returns the number of cases in a open system file. Some files
+do not store the number of cases. In these instances undef
+will be returned. Therefore, then programmer must check that the
+returned value is not undef before using it.
=cut