would be longer than 60 characters; otherwise it is padded on the right
with spaces.
+The product name field allow readers to behave differently based on
+quirks in the way that particular software writes system files.
+@xref{Value Labels Records}, for the detail of the quirk that the PSPP
+system file reader tolerates in files written by ReadStat, which has
+@code{https://github.com/WizardMac/ReadStat} in @code{prod_name}.
+
@anchor{layout_code}
@item int32 layout_code;
Normally set to 2, although a few system files have been spotted in
@tab @code{EDATE}
@item 39
@tab @code{SDATE}
+@item 40
+@tab @code{MTIME}
+@item 41
+@tab @code{YMDHMS}
@end multitable
@end quotation
have value labels, but their value labels are recorded using a
different record type (@pxref{Long String Value Labels Record}).
+ReadStat (@pxref{File Header Record}) writes value labels that label a
+single value more than once. In more detail, it emits value labels
+whose values are longer than string variables' widths, that are
+identical in the actual width of the variable, e.g.@: labels for
+values @code{ABC123} and @code{ABC456} for a string variable with
+width 3. For files written by this software, PSPP ignores such
+labels.
+
The value label record has the following format:
@example
@item int32 n_lines;
Number of lines of documents present. This should be greater than
-zero, but the system file writer that identifies itself as
-@url{https://github.com/WizardMac/ReadStat} writes document records
-with zero @code{n_lines}.
+zero, but ReadStats writes system files with zero @code{n_lines}.
@item char lines[][80];
Document lines. The number of elements is defined by @code{n_lines}.
variable @code{bias} from the file header. For example,
code 105 with bias 100.0 (the normal value) indicates a numeric variable
of value 5.
-One file has been seen written by SPSS 14 that contained such a code
-in a @emph{string} field with the value 0 (after the bias is
-subtracted) as a way of encoding null bytes.
+
+A code of 0 (after subtracting the bias) in a string field encodes
+null bytes. This is unusual, since a string field normally encodes
+text data, but it exists in real system files.
@item 252
End of file. This code may or may not appear at the end of the data