Re: [patch]: Add check for stdint header

[Richard Guenther <richard.guenther@gmail.com>]

On Fri, Sep 4, 2009 at 9:49 AM, Kai Tietz<ktietz70@googlemail.com> wrote:
> 2009/9/3 Richard Guenther <richard.guenther@gmail.com>:
>> On Thu, Sep 3, 2009 at 1:05 PM, Kai Tietz<ktietz70@googlemail.com> wrote:
>>> 2009/9/3 Richard Guenther <richard.guenther@gmail.com>:
>>>> On Thu, Sep 3, 2009 at 12:18 AM, Kai Tietz<ktietz70@googlemail.com> wrote:
>>>>> Hello,
>>>>>
>>>>> this patch adds to gcc's system.h file the include of stdint.h file,
>>>>> if present. If it doesn't finds this header it defines uintptr_t as
>>>>> 'unsigned long' and intptr_t as 'long'.
>>>>
>>>> The toplevel already has support for creating a stdint comaptible header,
>>>> you should probably simply use that.  See config/stdint*.m4.
>>>>
>>>> Richard.
>>>
>>> Well, we could extend this, but autoconf 2.64 supports the
>>> AC_TYPE_UINTPTR_T and AC_TYPE_INTPTR_T, and defines the types
>>> uintptr_t & intptr_t (as macros) for hosts without stdint.h fine.
>>
>> I'd say use the exisitng support - it's already heavily used by target
>> libs which
>> just do
>>
>> GCC_HEADER_STDINT(gstdint.h)
>>
>> and then include gstdint.h instead of stdint.h.
>>
>> The question is of course if it works well enough for the host, but
>> you'll find out.
>>
>> Richard.
>
> Well, I tested things about it. There are two issues I found about the
> use of gstdint.h instead of using 2.64 UINTPTR_T and INPTR_T checks.
> First the gstdint.h needs to generated dependent and added to the
> include CFLAGS options, well this isn't hard. But by using it in
> system.h header all function decl checks seems to fail. I tested the
> other variant by using
> #ifdef HAVE_STDINT_H
> #include <stdint.h>
> #endif
> in system.h and it bootstraps on linux without issues.
>
> So I would like to use the previous patch without gstdint.h header for
> solving this issue.

I suppose the explicit check for stdint.h is not necessary and you need to
cover for the case where inttypes.h provides the required definition.  See
the autoconf manual which says

 -- Macro: AC_TYPE_INTPTR_T
     If `stdint.h' or `inttypes.h' defines the type `intptr_t', define
     `HAVE_INTPTR_T'.  Otherwise, define `intptr_t' to a signed integer
     type wide enough to hold a pointer, if such a type exists.

I don't know what the canonical header inclusion case to use would be
though.  Maybe Ralf knows.

Richard.