Boszormenyi Zoltan írta:
> Hi,
>
> my question is that what platform were these
> functions developed and tested?
>
> We have come across a value that fails a NOT NULL
> constraint upon INSERT under HP-UX/IA64, but not
> under x86-64 Linux. The value in question is
> 1.9999999999999998 assigned to a "double" variable.
> Under HP-UX/IA64, testing with risnull() from
> the application indeed returns true, but under
> Linux/x86-64 returns false.
>
> I will test rsetnull() results on real Informix under
> HP-UX/IA64.
>
I have tested it under ESQL/C on HP-UX/ia64 and
this happened:
- rsetnull() on a double value creates
FF FF FF FF FF FF FF FF
- the value causing the error above is
3F FF FF FF FF FF FF FF
It seems that this function in ecpglib/misc.c has
an off-by-one bug as it's interpreted by the HP-UX CC:
static bool
_check(unsigned char *ptr, int length)
{
for (; length > 0 && ptr[--length] == 0xff;);
if (length <= 0)
return true;
return false;
}
I suspect that GCC does the "--length" after checking
"length > 0" and before checking the "ptr[...] == 0xff",
but HP CC does it before checking "length > 0".
The attached patch solves the problem.
Best regards,
Zoltán Böszörményi
--
Bible has answers for everything. Proof:
"But let your communication be, Yea, yea; Nay, nay: for whatsoever is more
than these cometh of evil." (Matthew 5:37) - basics of digital technology.
"May your kingdom come" - superficial description of plate tectonics
----------------------------------
Zoltán Böszörményi
Cybertec Schönig & Schönig GmbH
http://www.postgresql.at/
*** pgsql.4/src/interfaces/ecpg/ecpglib/misc.c.old 2009-11-19 19:50:38.000000000 +0100
--- pgsql.4/src/interfaces/ecpg/ecpglib/misc.c 2009-11-19 19:51:23.000000000 +0100
***************
*** 364,373 ****
static bool
_check(unsigned char *ptr, int length)
{
! for (; length > 0 && ptr[--length] == 0xff;);
! if (length <= 0)
! return true;
! return false;
}
bool
--- 364,375 ----
static bool
_check(unsigned char *ptr, int length)
{
! int i;
! for (i = 0; i < length && ptr[i] == 0xff; i++)
! ;
! if (i < length)
! return false;
! return true;
}
bool
--
Sent via pgsql-hackers mailing list ([email protected])
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-hackers
