Re: inttypes.h bug leads to inconsistent warnings cross platform

["Joseph S. Myers" <joseph at codesourcery dot com>]

On Wed, 10 Sep 2014, Joel Sherrill wrote:

> Adding Joseph Myers since newlib-stdint.h appears to have
> originated with him.

Well - newlib-stdint.h was designed to replicate the logic that already 
existed in newlib to define these types, which defined intptr_t to be the 
same as ptrdiff_t, and uintptr_t to be the corresponding unsigned type 
(normally the same as size_t).

> Does anyone have any ideas on how to address this? Is there some
> piece of info from gcc now to for inttypes.h to make the right
> selection? Or can gcc provide another cpp macro which would help?

GCC's predefines are intended for stdint.h, not for inttypes.h given 
that's not required for freestanding implementations so GCC doesn't try to 
provide it.

You could have a header varying depending on the architecture (or with 
architecture conditionals) that embeds the logic about the choice of types 
here.  Or you could do some sort of hack along the lines of

#define signed +0
#define int +0
#define long +1
#if __INTPTR_TYPE__ == 2
/* long long */
#elif __INTPTR_TYPE__ == 1
/* long */
#elif __INTPTR_TYPE__ == 0
/* int */
#else
#error
#endif
#undef signed
#undef int
#undef long

to identify what type is being used (it's invalid to include a standard 
header with any keywords defined as macros, so it's valid for such a 
header to temporarily define such macros then undefine them).

-- 
Joseph S. Myers
joseph@codesourcery.com