sys-file-reader: Accept document records with no document lines.

[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..fb131f5274f0d61e90f9eefdf0c994c413b7e468 100644 (file)
--- a/doc/dev/system-file-format.texi
+++ b/doc/dev/system-file-format.texi
@@ -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}.