Subject Re: [IB-Architect] dsql/dsql.c v2 A Cursor Too Far.
Author Chris Jewell
> From: "Griffin, Patrick J." <griffin@...>
> Date: Fri, 8 Sep 2000 15:10:16 -0400

> Meditating on the randomness of this problem I was stuck by the thought:
> COBOL doesn't use null terminated strings.
> Studying GDS_DSQL_SET_CURSOR I see:
> length = name_length (input_cursor);
> for (i=0; i<length && i< sizeof(cursor)-1; i++)
> cursor [i] = UPPER7 (input_cursor [i]);
> cursor [i] = '\0';
> where, I believe, name_length is expecting a null terminated string.

It is, and I think you're in the right area there, but there is more
to the story. The static function name_length() is called twice in
GDS_DSQL_SET_CURSOR(), but those calls don't really want the same

The first call is handling a traditional, non-delimited identifier,
and therefore should stop at the first blank it finds (because blanks
are not permitted in an ordinary identifier). That is exactly what
name_length() did in 5.6.

The second call is handling something which *may* have been a
delimited identifier which had its delimiters stripped off, and
therefore is permitted to contain embedded blanks (but is sure to be
null- terminated, because the null was inserted either 2 lines or 10
lines above that second call to name_length()), and should only ignore
trailing blanks, not embedded blanks. The 6.0 version of
name_length() handles that situation just fine.

We need 2 different functions to be called from those two places,
quite apart from any questions about null-terminated strings. The
first name_length() call should instead call something, which doesn't
exist yet, but will probably look like the following UNTESTED code.

static USHORT length_before_first_blank(TEXT *name)
TEXT * first_blank;

first_blank = (TEXT *) strchr((char *) name, ' ');
if (first_blank)
return (USHORT) (first_blank - name);
return (USHORT) strlen((char *) name);

(The 5.6 version of name_length() would also do fine, but as an
Inprise employee I feel on safer ground suggesting a new fix than
posting a chunk of the pre-open-source code in a public place. I
don't want the rottweilers nipping at the seat of my trousers. <grin>)

Delimited identifiers are new in 6.0, which makes it unsurprising for
code related to delimited idents to turn up at the site of something
that worked for several previous releases but fails in 6.0.

That COBOL doesn't use null-terminated strings is very old news, yet
your applications work with previous releases of IB. In IB 5.X, I can
see that the name was ALWAYS passed to name_length() as in 6.0, with
no worries at all. It appears to me that the implementor of delimited
identifiers introduced the bug you are experiencing when he changed
the semantics of name_length(), and that my suggestion above should
fix it.

Chris Jewell developer/sysadmin voice: 831-431-6531
cjewell@... InterBase Software, Borland-Inprise fax: 831-431-6510