Re: Strange interval arithmetic

On Wed, Nov 30, 2005 at 05:23:23PM -0500, Tom Lane wrote:
> Michael Fuhr <mike(at)fuhr(dot)org> writes:
> > I usually check both in my own code but I noticed several places
> > where PostgreSQL doesn't, so I kept that style. I'll check both
> > if that's preferred.
>
> I'd say not --- it's more code and it makes a possibly unwarranted
> assumption about strtol's behavior.

OTOH, it might be an unwarranted assumption that ERANGE alone
indicates error. It's possible that on some system errno's value
is meaningless unless strtol() returns one of the documented
indicators (LONG_MAX or LONG_MIN). I've seen system calls that
behave that way: errno might get set in a non-error situation due
to the underlying implementation (e.g., wrappers around socket
functions in userland thread implementations), but the programmer
has no business looking at errno unless the function returns -1.

--
Michael Fuhr