Re: Using the return value of strlcpy() and strlcat()

Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> writes:

> Ashwin Agrawal <aagrawal(at)pivotal(dot)io> writes:
>> On Wed, Mar 13, 2019 at 9:51 AM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>>> I don't think that's a safe transformation: what strlcpy returns is
>>> strlen(src), which might be different from what it was actually
>>> able to fit into the destination.

Yeah, Andrew Gierth pointed this out on IRC as well.

>>> Sure, they're equivalent if no truncation occurred; but if we were
>>> 100.00% sure of no truncation, we'd likely not bother with strlcpy.
>
>> So, if return value < length (3rd argument) we should be able to use the
>> return value and avoid the strlen, else do the strlen ?
>
> Mmm ... if there's a way to do it that's not messy and typo-prone,
> maybe. But I'm dubious that the potential gain is worth complicating
> the code. The strings involved aren't usually all that long.

Please consider this patch withdrawn.

- ilmari
--
"I use RMS as a guide in the same way that a boat captain would use
a lighthouse. It's good to know where it is, but you generally
don't want to find yourself in the same spot." - Tollef Fog Heen