Extension (type 7) records, in ascending numerical order of their
subtypes.
+System files written by SPSS include at most one of each kind of
+extension record. This is generally true of system files written by
+other software as well, with known exceptions noted below in the
+individual sections about each type of record.
+
@item
Dictionary termination record.
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
Number of data elements per case. This is the number of variables,
except that long string variables add extra data elements (one for every
8 characters after the first 8). However, string variables do not
-contribute to this value beyond the first 255 bytes. Further, system
-files written by some systems set this value to -1. In general, it is
+contribute to this value beyond the first 255 bytes. Further, some
+software always writes -1 or 0 in this field. In general, it is
unsafe for systems reading system files to rely upon this value.
@item int32 compression;
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
Record type. Always set to 6.
@item int32 n_lines;
-Number of lines of documents present.
+Number of lines of documents present. This should be greater than
+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}.
@item char attributes[];
The attributes, in a text-based format.
-In record type 17, this field contains a single attribute set. An
+In record subtype 17, this field contains a single attribute set. An
attribute set is a sequence of one or more attributes concatenated
together. Each attribute consists of a name, which has the same
syntax as a variable name, followed by, inside parentheses, a sequence
an attribute with a single value and an attribute array with one
element.
-In record type 18, this field contains a sequence of one or more
+In record subtype 18, this field contains a sequence of one or more
variable attribute sets. If more than one variable attribute set is
present, each one after the first is delimited from the previous by
@code{/}. Each variable attribute set consists of a long
variable name,
followed by @code{:}, followed by an attribute set with the same
-syntax as on record type 17.
+syntax as on record subtype 17.
+
+System files written by @code{Stata 14.1/-savespss- 1.77 by
+S.Radyakin} may include multiple records with subtype 18, one per
+variable that has variable attributes.
The total length is @code{count} bytes.
@end table
projects / pspp / blobdiff