sys-file-reader: Tolerate nominal case size of 0 without warning.

[pspp] / doc / dev / system-file-format.texi

diff --git a/doc/dev/system-file-format.texi b/doc/dev/system-file-format.texi
index 7cc0342c4cd81e966f45abbeafb9c65a3d2cce60..e52b9571166a25b477a8f6263f34d0960b9f0423 100644 (file)
--- a/doc/dev/system-file-format.texi
+++ b/doc/dev/system-file-format.texi
@@ -232,8 +232,8 @@ file's integer endianness (@pxref{System File Format}).
 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
 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;
 unsafe for systems reading system files to rely upon this value.
 
 @item int32 compression;


@@ -605,7 +605,10 @@ char                lines[][80];
 Record type.  Always set to 6.
 
 @item int32 n_lines;
 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 the system file writer that identifies itself as
+@url{https://github.com/WizardMac/ReadStat} writes document records
+with zero @code{n_lines}.

 
 @item char lines[][80];
 Document lines.  The number of elements is defined by @code{n_lines}.
 
 @item char lines[][80];
 Document lines.  The number of elements is defined by @code{n_lines}.