Re: [HACKERS] Strange interval arithmetic

I started working on this problem on Tuesday, but was in New York City
yesterday so I was not able to comment on this patch before. I think
the one applied is great. (I added C comments on the use of "errno =
0".

Here is the patch I was working on. It does us a separate libpq
strtol() function, but I question whether it is worth it, or if it is
meaningful when used by FRONTEND applications. Anyway, I am just
throwing it out if it gives others ideas.

---------------------------------------------------------------------------

Michael Fuhr wrote:
> On Wed, Nov 30, 2005 at 02:01:46PM -0500, Tom Lane wrote:
> > Michael Fuhr <mike(at)fuhr(dot)org> writes:
> > > Any preferences on an approach? The simplest and easiest to verify
> > > would be to raise an error for just this particular case; a TODO
> > > item might be to change how the string is parsed to allow values
> > > larger than LONG_MAX.
> >
> > I think the latter would be a feature enhancement and therefore not
> > good material to back-patch. Just erroring out seems appropriate
> > for now.
>
> Agreed. I'm thinking about rewriting strtol() calls in datetime.c
> to look like this:
>
> errno = 0;
> val = strtol(field[i], &cp, 10);
> if (errno == ERANGE)
> return DTERR_FIELD_OVERFLOW;
>
> Does that look okay? Or would you rather raise an error with ereport()?
>
> > > I see several calls to strtol() that aren't checked for overflow but
> > > that might not be relevant to this problem, so I'm thinking this patch
> > > ought not touch them. Maybe that's another TODO item.
> >
> > If it's possible for them to be given overflowing input, they probably
> > ought to be checked.
>
> I'm looking at all the strtol() calls in datetime.c right now; I
> haven't looked anywhere else yet. Should I bother checking values
> that will be range checked later anyway? Time zone displacements,
> for example?
>
> --
> Michael Fuhr
>
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