X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=doc%2Fdev%2Fsystem-file-format.texi;h=e52b9571166a25b477a8f6263f34d0960b9f0423;hb=f518002b6673e3bcc030c903378d5d75f64697ea;hp=7cc0342c4cd81e966f45abbeafb9c65a3d2cce60;hpb=e4f726ad61233531b155b62f0c99ff667b2c2e11;p=pspp

diff --git a/doc/dev/system-file-format.texi b/doc/dev/system-file-format.texi
index 7cc0342c4c..e52b957116 100644
--- 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
-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;
@@ -605,7 +605,10 @@ char                lines[][80];
 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}.