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Date:	Sun, 15 Mar 2009 10:48:12 -0400
From:	Charles Wilson <cygwin AT cwilson DOT fastmail DOT fm>
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To:	cygwin AT cygwin DOT com
Subject:	Re: long unsigned int vs. uint32_t again
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Andy Koppe wrote:
> Chuck wrote:
>> cygwin's <inttypes.h> has:
>> #define PRIu32 "lu"
>>
>> and <stdint.h> has
>> typedef unsigned int uint32_t;
>>
>> Is it possible that our inttypes.h should be changed, to use "u" for 8, 16, and 32 bits?
> 
> Yep, I'd say so.

Linux agrees with you.  Its inttypes.h has:

# if __WORDSIZE == 64
#  define __PRI64_PREFIX        "l"
#  define __PRIPTR_PREFIX       "l"
# else
#  define __PRI64_PREFIX        "ll"
#  define __PRIPTR_PREFIX
# endif

...

# define PRIu8          "u"
# define PRIu16         "u"
# define PRIu32         "u"
# define PRIu64         __PRI64_PREFIX "u"

and similar, throughout [*]. Fortunately, this file is from src/winsup,
not src/newlib, so we don't have to worry about the impact of any change
on other platforms supported by newlib.

Should I prepare a patch (and I assume we're not worried yet about
WORDSIZE==64)?

>>  Or is gcc's -Wformat=2 in 3.4.4 just too strict here -- and should be checking
>> the actual bitwidths of types against the formats, before assuming that
>> "lu" doesn't match uint32_t?
> 
> No. "long" and "int" are different types, and ignoring this would just
> store up trouble for when code is ported to platforms with 64-bit
> longs.

Ack.

--
Chuck


[*] The *FAST* macros follow a different pattern:

# define PRIuFAST8      "u"
# define PRIuFAST16     __PRIPTR_PREFIX "u"
# define PRIuFAST32     __PRIPTR_PREFIX "u"
# define PRIuFAST64     __PRI64_PREFIX "u"

because stdint.h has this (and similar, throughout):

typedef unsigned char           uint_fast8_t;
#if __WORDSIZE == 64
typedef unsigned long int       uint_fast16_t;
typedef unsigned long int       uint_fast32_t;
typedef unsigned long int       uint_fast64_t;
#else
typedef unsigned int            uint_fast16_t;
typedef unsigned int            uint_fast32_t;
__extension__
typedef unsigned long long int  uint_fast64_t;
#endif


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