system-file-format: More string fields with null bytes spotted.

Manoharan <s.manoharan@auckland.ac.nz> reported that he has also seen
system files that contain string fields with compressed null bytes, so
reword the description to make this sound less exotic.

diff --git a/doc/dev/system-file-format.texi b/doc/dev/system-file-format.texi
index 484fbb43f1eca08fc089bd0f5ec171215f279403..116fa6f787445fb5931e9ae2dafe87eb97782988 100644 (file)
--- a/doc/dev/system-file-format.texi
+++ b/doc/dev/system-file-format.texi
@@ -1572,9 +1572,10 @@ value @var{code} - @var{bias}, where
 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