FreeTDS Development Group

[Brian Bruns <camber AT ais.org>]

hi all,

I've removed the swap on the message number.  If someone needs to use 
broken SQL Servers with broken datetimes on big endian clients, you'll 
need to set emulate little endian in the freetds.conf file.  Let me know 
if there are still problems.

Brian

On Wed, 23 Jan 2002, Michael Horowitz wrote:

> I have tried using the datetime/money swaps with TDS versions 4.2 and 7.0
> with and without emulate little endian(for 4.2), and connecting to both MS
> SQL Server 7.0 and 2000, and it seems to have no effect at all.  Only the
> emulate little endian options(or using v7.0) seems to fix the
> datetime/money problems.
> 
> The bigger problem is that on big endian machines(for me Solaris 2.6), the
> error messages don't get handled properly, because the message number is
> double swapped and then truncated from 4 bytes to 2.  So, it ends up as
> zero, and from a discussion 2-3 weeks ago with Michael Peppler, it ends up
> being treated as a SQL PRINT statement.  When using freeTDS through
> DBD::Sybase, errors are never raised properly, and they all end up just
> being printed to STDERR(via the perl "warn" function).
> 
> The problem was in freetds-0.53/src/tds/token.c where if the client is
> emulating little endian either via the config option or by using tds
> version 7.0, tds_get_int would swap the bytes or the message number before
> returning the int, but then it would be swapped again right after.  For me
> I am always using emulate little endian anyway, so the easiest solution
> was to just remove the second swap, or condition the second swap only if
> emulate little endian was false.  I discussed this a while back with Mark
> Lilback, and he said that he had to look into it because it would still
> break something when not using emulate little endian.  I did some test of
> my own and differences between MS SQL Server 7.0 and 2000 seem to cause
> problems with this fix.
> 
> Now it seems that Chris Eleveld is having the same problems as me, and
> came up with the same fix, plus some others that I didn't notice.
> 
> For now it seems if I use the temporary patch of the swapping issue, and I
> am careful about the configuration I use, I can get it to work properly,
> but I would feel better if I knew that some sort of more complete
> permanent patch was going into the main code, so that I know future
> versions of freetds will work if I want to upgrade.
> I am not familiar enough with the code to make any sort of fix that I am
> sure wont break anything else.  I only read enough of the code to trace
> down that one swapping error.
> 
> Anyway, I would appreciate any help I can get to fix this properly.
> 
> Thanks,
> 
> Mike
> 
> > On Tue, 22 Jan 2002, Michael Horowitz wrote:
> > 
> > > Anyway, it seems that you have had a similar problem with the big endian
> > > issue as me, so I wanted to chyme in with my experience with it.  While
> > > either of the fixes seems to work under specific configurations, I am 
> > > not
> > > sure what the final fix should be to make it work under all platforms 
> > > and
> > > with all types of SQL Servers both MS and Sybase.
> > > 
> > > Do you have any other info that might help with this?
> > 
> > What I would like to do, is remove the datetime/money swaps entirely.  If
> > you are using FreeTDS on a big endian box against MS SQL, use emulate 
> > little endian.  Anything else works in bits and pieces here and there, but
> > then breaks with the next service pack.  It'll also simplify what is going
> > on underneath anyway.
> > 
> > Besides, TDS 7.0 is little endian only, and it doesn't appear that MS QA's
> > big endian machines so it's a crap shoot trying to get it working.
> > 
> > Brian
> 
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