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Date: Sun, 15 Mar 2009 01:43:41 -0400
From: Charles Wilson <cygwin AT cwilson DOT fastmail DOT fm>
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To: cygwin AT cygwin DOT com
Subject: long unsigned int vs. uint32_t again
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Why does the following give me a warning (with -Wformat=2):

      uint32_t seconds = ...
      uint32_t minutes = ...
      uint32_t hours   = ...
      snprintf(buf, sizeof(buf),
               "%" PRIu32 ":%02" PRIu32 ":%02" PRIu32,
               hours, minutes, seconds);

warning: long unsigned int format, uint32_t arg (arg 4)
                                                    warning: long
unsigned int format, uint32_t arg (arg 5)
                                  warning: long unsigned int format,
uint32_t arg (arg 6)

If you've got a uint32_t, then 'PRIu32' is the correct code to use,
right? What OTHER code could there be for printing unsigned, 32bit,
integers?

cygwin's <inttypes.h> has:
#define PRIu8 "u"
#define PRIu16 "u"
#define PRIu32 "lu"
#define PRIu64 "llu"

and <stdint.h> has
typedef unsigned int uint32_t;

This is on cygwin-1.7.0-43, with gcc-3.4.4-999.  Is it possible that our
inttypes.h should be changed, to use "u" for 8, 16, and 32 bits?  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?

--
Chuck

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