Re: Why the asprintf patch is still breaking the buildfarm

On Tue, Oct 22, 2013 at 8:58 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:

> So I returned from vacation only to find that the buildfarm has a bad case
> of acne. All the Windows members are red or pink, and have been for
> awhile. Sigh.
>
> After some research I believe that I understand the reason for the CHECK
> failures, at least:
>
> 1. src/port/asprintf.c exhibits a truly touching faith that vsnprintf will
> report exactly the number of bytes that would have been required, even if
> the buffer is not that large. While this is what is specified in recent
> versions of the POSIX standard, older platforms have much sketchier
> behavior.
>
> 2. In particular, our own src/port/snprintf.c follows the SUS v2 rule that
> it should report the number of bytes it *actually wrote*. This means
> that asprintf.c will never think that its initial 128-byte allocation was
> insufficient. So, on platforms where we use this implementation (notably
> including Windows), the result of any asprintf call is effectively
> truncated at 128 bytes.
>
>
Thanks for looking at this. I had a bash and trying to figure out why
vcregress check would not work last night and didn't get very far...
I can confirm that you are right just by changing the 128 into 12800 and
compiling, vcregress check worked after that.

Regards

David Rowley

>
> I have a lot of other gripes about this whole patch, but they can
> wait till tomorrow.
>
> regards, tom lane
>
>
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