Re: AC_SYS_LARGEFILE

[Evgeny Grin]

On 21.09.2023 0:49, Paul Eggert wrote:
> On 2023-09-20 05:52, Evgeny Grin wrote:
> > If you need have a function with "file offset" argument then use 
> > either 'uint64_t'
>
> Although your other advice is good, this one is suspect. I'm glad I 
> didn't follow similar advice to use 'int32_t' or 'long' for file offsets 
> back in the day.

Most probably 9 petabytes limitation (int64_t) would be sufficient for 
direct file addressing for the next two decades or a bit longer.
Your public API will likely evolve by this time, and you'll add new 
functionality as needed.

> Also, to be pedantic, the types int64_t and uint64_t are optional in 
> POSIX, and portable programs shouldn't use them unconditionally.

Yes, '[u]int64_t' is optional. Actually, '[u]int32_t' is optional too 
(according to C99), so a very portable programs may avoid it as well. 
However, in practice, any modern platform supports it, so if you want to 
limit your portability to realistic scenarios, you may safely use them.

For higher portability you may use '[u]int_least32_t' and 
'[u]int_least64_t', both are mandatory.

--
Evgeny

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