inttypes.h bug leads to inconsistent warnings cross platform

[Joel Sherrill]

Hi

This code will compile warning free on some targets but not
on others. This issue should exist on all targets base on the
CPU architecture as shown below.

#include <stdio.h>
#include <inttypes.h>

void f( uintptr_t p )
{
  printf( "Value = %" PRIuPTR "\n", p );
}

This is a list of warning/no warning for every RTEMS target
that compiles on the head.

=== arm-rtems4.11-gcc - no warning
=== bfin-rtems4.11-gcc - warning
=== i386-rtems4.11-gcc - warning
=== lm32-rtems4.11-gcc - no warning
=== m68k-rtems4.11-gcc - warning
=== nios2-rtems4.11-gcc - no warning
=== or1k-rtems4.11-gcc - warning
=== powerpc-rtems4.11-gcc - no warning
=== sh-rtems4.11-gcc - no warning
=== sparc64-rtems4.11-gcc - no warning
=== sparc-rtems4.11-gcc - no warning
=== v850-rtems4.11-gcc - no warning

I have tracked this down to newlib's inttypes.h does not detect
when gcc defines integer pointer types to long. PRIuPTR turns
into "u" not "ul".

$ or1k-rtems4.11-gcc -dM -E - </dev/null | grep INTPTR_T
#define __INTPTR_TYPE__ long int
#define __UINTPTR_TYPE__ long unsigned int
$ arm-rtems4.11-gcc -dM -E - </dev/null | grep INTPTR_T
#define __INTPTR_TYPE__ int
#define __UINTPTR_TYPE__ unsigned int

On the above two targets __PTRDIFF_TYPE__ is the same.

The code in inttypes.h in question is:

#if PTRDIFF_MAX <= __INTTYPES_EXP(INT_MAX)
# define __PRIPTR(x) __STRINGIFY(x)
# define __SCNPTR(x) __STRINGIFY(x)
#elif PTRDIFF_MAX <= __INTTYPES_EXP(LONG_MAX) || !defined(__have_longlong64)
# define __PRIPTR(x) __STRINGIFY(l##x)
# define __SCNPTR(x) __STRINGIFY(l##x)
#else
# define __PRIPTR(x) __STRINGIFY(ll##x)
# define __SCNPTR(x) __STRINGIFY(ll##x)
#endif

Any thoughts on how to detect when it should use
"ul" for long uinptr_t instead of "u" for targets with
int uintptr_t?

I don't see any related variables that differ in the predefined
CPP macros except the actual type.

Thanks.

-- 
Joel Sherrill, Ph.D.             Director of Research & Development
joel.sherrill@OARcorp.com        On-Line Applications Research
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