Hi Simon,
On Mon, 22 Dec 2014 21:46:26 -0700 Simon Glass sjg@chromium.org wrote:
Hi Masahiro,
On 22 December 2014 at 03:16, Masahiro Yamada yamada.m@jp.panasonic.com wrote:
CONFIG_USE_STDINT was introduced to use compiler-provided types for fixed-width variables. This must be consistent everywhere to avoid warnings/errors including printf() and friends.
Assume the code below
uint32_t foo;
printf("foo= %x\n", foo);
If <stdint.h> is included, uint32_t is defined by the compiler. The code above only works on compilers that define "uint32_t" as "unsigned int". Actually there exist compilers that define "uint32_t" as "unsigned long".
Going forward, to print out fixed-width variables, we always have to use PRIxN like this
uint32_t foo;
printf("foo= " PRIx32 "\n", foo);
Notice,
- Typedefs ( uint32_t, int32_t etc.) are provided by <stdint.h>
- Printf formats ( PRIx32, PRId32 etc.) are provided by <inttypes.h>
Also notice, it makes sense only when <stdint.h> and <inttypes.h> are provided by the same compiler. ^^^^^^^^^^^^^^^^^^
Commit 4166ecb24 (Add some standard headers external code might need) added hard-coded include/inttypes.h. It provides hard-coded PRIx32 "x", but it does not make sense. Some compiler's <stdint.h> define "uint32_t" as "unsigned long" and expect the format string "lx" to print out "uint32_t" variable.
This commit:
Adds scripts/gcc-have-stdint.sh to check if the compiler is providing both <stdint.h> and <inttypes.h>
Modifies config.mk to error-out if CONFIG_USE_STDINT is enabled, but <stdint.h> or <inttyps.h> is missing
Modifies the top Makefile to delete "-nostdinc" option and allow to include compiler-provided <inttypes.h>
Remove hard-coded include/inttypes.h
This patch looks good to me except that I don't understand why you are removing inttypes.h? Where will the PRI defines come from? Or is it because you are fixing things such that the defines are not needed anymore?
According to this question, I am afraid you are not understanding <inttypes.h> very well. Maybe is this page useful? http://pubs.opengroup.org/onlinepubs/009695399/basedefs/inttypes.h.html
My commit description has also answered your question:
Notice, - Typedefs ( uint32_t, int32_t etc.) are provided by <stdint.h> - Printf formats ( PRIx32, PRId32 etc.) are provided by <inttypes.h> Also notice, it makes sense only when <stdint.h> and <inttypes.h> are provided by the same compiler.
Best Regards Masahiro Yamada