Paul Eggert <eggert@cs.ucla.edu> schrieb am Fr., 20. Nov. 2015 um 21:32 Uhr:

> Philipp Stephani wrote:
> > Daniel felt pretty strongly about using int64 for fixnums.
>
> As I recall, he felt that we shouldn't use EMACS_INT in the module API, and
> int64_t was merely a means to that goal. If so, that's not a reason to
> prefer
> int64_t over intmax_t; it's merely a reason to make sure that intmax_t is
> at
> least as portable as int64_t is in this area. Which it is.
>
>  > Is there any reason to change that?
>
> Yes, int64_t is not required by POSIX, C99, etc.  That is, int64_t is an
> optional type.  In contrast, intmax_t is required on all C99 platforms,
> and it
> has better support (e.g., there's a printf format specifier for it), so
> there
> are advantages to intmax_t over int64_t.  I don't know of any advantage
> int64_t
> would have over intmax_t on any platform that Emacs supports.
>

It would be guaranteed to always have the same size, if available. My
understanding is that intmax_t could differ between compilers even on the
same machine, which would silently break compatibility.