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long unsigned int vs. uint32_t again
- From: Charles Wilson <cygwin at cwilson dot fastmail dot fm>
- To: cygwin at cygwin dot com
- Date: Sun, 15 Mar 2009 01:43:41 -0400
- Subject: long unsigned int vs. uint32_t again
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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