bz(at)mailinator(dot)com writes:
> I have a table containing ISBNs stored as the isbn type provided by the isn
> extension. In certain cases an ISBN in ISBN10 form is considered unequal to
> the same ISBN in ISBN13 form.
I poked at this a little bit. I think the issue may be that this bit
at line 832 in isn.c:
case ISBN:
memcpy(buf, "978", 3);
supposes that all ISBNs should have prefix 978, whereas your example is
using prefix 979, which seems to be also valid according to code a few
lines above. I don't know enough about the whole ISBN/EAN mess to
understand what this should be doing instead, though.
regards, tom lane