On Thu, Apr 18, 2024 at 8:47 PM Peter Eisentraut <peter@eisentraut.org> wrote:
> Maybe this means something like our int64 is long long int but the
> system's int64_t is long int underneath, but I don't see how that would
> matter for the limit macros.
Agreed, so I don't think it's long vs long long (when they have the same width).
I wonder if this comment is a clue:
static char *
inet_net_ntop_ipv6(const u_char *src, int bits, char *dst, size_t size)
{
/*
* Note that int32_t and int16_t need only be "at least" large enough to
* contain a value of the specified size. On some systems, like Crays,
* there is no such thing as an integer variable with 16 bits. Keep this
* in mind if you think this function should have been coded to use
* pointer overlays. All the world's not a VAX.
*/
I'd seen that claim before somewhere else but I can't recall where.
So there were systems using those names in an ad hoc unspecified way
before C99 nailed this stuff down? In modern C, int32_t is definitely
an exact width type (but there are other standardised variants like
int_fast32_t to allow for Cray-like systems that would prefer to use a
wider type, ie "at least", 32 bits wide, so I guess that's what
happened to that idea?).
Or perhaps it's referring to worries about the width of char, short,
int or the assumption of two's-complement. I think if any of that
stuff weren't as assumed we'd have many problems in many places, so
I'm not seeing a problem. (FTR C23 finally nailed down
two's-complement as a requirement, and although C might not say so,
POSIX says that char is a byte, and our assumption that int = int32_t
is pretty deeply baked into PostgreSQL, so it's almost impossible to
imagine that short has a size other than 16 bits; but these are all
assumptions made by the OLD coding, not by the patch I posted). In
short, I guess that isn't what was meant.