RE: Need Help on dblib program

> From: Steven J. Backus [mailto:backus@xxxxxxxxxxxxx]
> Sent: July 31, 2003 5:08 PM
> 
> > What does your log show?  Does it stop just before the 
> "family" conversion?
> 
> The last few lines from the log are:
> 
> 15:01:26.158004 dbconvert() srctype = 39 desttype = 47
> 15:01:26.269232 dbconvert() calling tds_convert
> 15:01:26.378415 dbconvert() called tds_convert returned 4
> 15:01:26.491374 dbconvert() outputting 4 bytes character data 
> destlen = -2 

Well, then we know things went awry before that.  We have to look at
tds_convert's input (see my last message) but I'll bet 10:1 it's corrupted.
Why is it four bytes?  

A little before the I5 conversion is the dage conversion.  Your table has
that as datatype float, 8 bytes, and you're binding it to a C float, 4
bytes.  Does anything change if you redefine the age column as datatype
"real" instead?  

> Then I do "c" again, another watch point appears:
> 
> Old value = 84 'T'
> New value = 0 '\000'
> dbconvert (dbproc=0x807b910, srctype=39, src=0x807d214 
> "I64TY", srclen=3, desttype=47, 
>     dest=0x804763c "I64", destlen=-2) at dblib.c:1907
> 1907                            ret = len;
> (gdb) bt
> #0  dbconvert (dbproc=0x807b910, srctype=39, src=0x807d214 
> "I64TY", srclen=3, desttype=47, 
>     dest=0x804763c "I64", destlen=-2) at dblib.c:1907
> #1  0x804a471 in buffer_transfer_bound_data (rowtype=-1, 
> compute_id=0, buf=0x807b914, 
>     dbproc=0x807b910, row_num=2) at dblib.c:449

Oh, boy.  We're supposed to believe that assigning "len" to "ret" changes
the value of your bound variable.  I'll choose to believe that's not true,
that it's actually the statement prior:

                dest[len] = 0;

that's doing the job, as expected.  The real question is: what happened to
cause tds_convert() to return 4 when its varchar input was "I64" and srclen
was 3?  

> And yet again:
> 
> Hardware watchpoint 2: *(DBCHAR *) 134510143
> 
> Old value = 0 '\000'
> New value = -33 'ß'
> (gdb) bt
> #0  0xdfae22bf in ?? ()
> #1  0xdfad3339 in ?? ()

This is expected.  You're exiting the program.  Memory's being freed and
reused on the way out.  

The next step is to try changing the age to type real.  That will avoid the
8->4 byte conversion, and I think the problem will go away.  If not, log the
inputs to dbconvert and tds_convert.  

My guess is we're doing something silly with dage, but I don't see what it
is yet.  

--jkl
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