On Thu, Feb 01, 2024 at 02:13:11PM +0100, Jakub Jelinek wrote:
> Or hwint.h could define PRIusize_t etc. macros and some corresponding type
> to be used in casts, something like
> #if SIZE_MAX == LONG_LONG_MAX
> #define PRIusize_t HOST_LONG_LONG_FORMAT "u"
> #define fmt_size_t unsigned long long
> #elif SIZE_MAX == LONG_MAX
> #define PRIusize_t HOST_LONG_FORMAT "u"
> #define fmt_size_t unsigned long
> #elif SIZE_MAX == INT_MAX
> #define PRIusize_t "u"
> #define fmt_size_t unsigned int
> #else
> #error "Unsupported size_t"
> #endif
>
> and then use
> "... %" PRIusize_t " ... ", ... (fmt_size_t) (some_size_t_expr), ...
>
> Or at configure time figure out which exact type size_t is say (unsigned
> long long vs. unsigned long vs. unsigned int) using templates and
> use that info to pick the right format modifier depending on that, then
> the casts aren't needed.
Note, the former is probably better and might need some fallback, because
on some platforms size_t is some weird type like __uint20 or similar.
So maybe just start with smallest to largest, #if SIZE_MAX <= INT_MAX ...
#elif SIZE_MAX <= LONG_MAX ... #else ... #endif.
Jakub
