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  • From: LacaK <lacak AT zoznam.sk>
  • To: FreeTDS Development Group <freetds AT lists.ibiblio.org>
  • Subject: Re: [freetds] tds_get_size_by_type for SYBMSDATE
  • Date: Fri, 11 Apr 2014 09:45:23 +0200

Frediano Ziglio wrote / napĂ­sal(a):
2014-04-10 8:48 GMT+01:00 LacaK <lacak AT zoznam.sk>:
24 ?? On my 64 bit machine is 16 and should be 16.
I did some testing and googling and it seems, that inter - padding in
structures can vary compiler to compiler.
(as C++ standard does not strictly defines binary layout)
It seems, that Microsoft uses his "own padding and sizing" with bit-fields.

I did small change in TDS_DATETIMEALL, which gives me now 16 bytes size (as
in your case):
typedef struct
{
TDS_UINT8 time; /* time, 7 digit precision */
TDS_INT date; /* date, 0 = 1900-01-01 */
TDS_SMALLINT offset; /* time offset */
// HERE "unsigned short" instead of "unsigned":
unsigned short time_prec:4;
unsigned short has_time:1;
unsigned short has_date:1;
unsigned short has_offset:1;
} TDS_DATETIMEALL;

So now we have: 8 bytes + 4 bytes + 2 bytes + 2 bytes = 16 bytes (seems,
that no padding occurs at end because 16 mod 8 = 0)
Can you change please "unsigned" to "unsigned short" in definition of
TDS_DATETIMEALL ?

-Laco.


Was thinking the same. Probably even better TDS_USMALLINT
I see, that you have already commited this change. Thanks.
Now I hope, that this struct will not change "often" in future, else it will break applications which will rely on exact binary layout of it.
(like other languages which link to dblib.dll)
-Laco.





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