Subject: Re: [bug-diffutils] bug#24311: bug#24311: bug#24311: [PATCH] maint: accommodate LP64 systems

From: Paul Eggert <[email-masked]>
Date: Sat, 27 Aug 2016 16:09:19 -0700

Andreas Grünbacher wrote:
> FWIW, patch has the following typedef for line numbers:
>
>   typedef off_t lin;
>
> Maybe it would be time to switch to int64_t / uint64_t and PRId64 /
> PRIu64 in diff as well as in patch?

No, as 'diff' puts all its data into memory (hence ptrdiff_t is appropriate), 
whereas 'patch' can operate on files that do not fit into memory (hence off_t is 
appropriate).

Generally speaking, portable code should be wary of using exact-sized types like 
int64_t. POSIX and the C standard don't even require int64_t, and there are a 
few (admittedly rare) implementations that lack int64_t. Even if int64_t was 
universally available, it would be better to use types like ptrdiff_t and off_t 
that reflect actual implementation limitations, as that better documents the code.