Re: [PATCH] Fix some printf format warnings
On Wed, 30 Sep 2009, Ramsay Jones wrote:
Show 32 quoted lines
>
> commit 51ea551 ("make sure byte swapping is optimal for git"
> 2009-08-18) introduced a "sane definition for ntohl()/htonl()"
> for use on some GNU C platforms. Unfortunately, for some of
> these platforms, this results in the introduction of a problem
> which is essentially the reverse of a problem that commit 6e1c234
> ("Fix some warnings (on cygwin) to allow -Werror" 2008-07-3) was
> intended to fix.
>
> In particular, on platforms where the uint32_t type is defined
> to be unsigned long, the return type of the new ntohl()/htonl()
> is causing gcc to issue printf format warnings, such as:
>
> warning: long unsigned int format, unsigned int arg (arg 3)
>
> (nine such warnings, covering six different files). The earlier
> commit (6e1c234) needed to suppress these same warnings, except
> that the types were in the opposite direction; namely the format
> specifier ("%u") was 'unsigned int' and the argument type (ie the
> return type of ntohl()) was 'long unsigned int' (aka uint32_t).
>
> In order to suppress these warnings, the earlier commit used the
> (C99) PRIu32 format specifier, since the definition of this macro
> is suitable for use with the uint32_t type on that platform.
> This worked because the return type of the (original) platform
> ntohl()/htonl() functions was uint32_t.
>
> In order to suppress these warnings, we change the return type of
> the new byte swapping functions in the compat/bswap.h header file
> from 'unsigned int' to uint32_t.
>
> Signed-off-by: Ramsay Jones <ramsay@ramsay1.demon.co.uk>Acked-by: Nicolas Pitre <nico@fluxnic.net>
Show 30 quoted lines
> ---
> compat/bswap.h | 4 ++--
> 1 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/compat/bswap.h b/compat/bswap.h
> index 7246a12..5cc4acb 100644
> --- a/compat/bswap.h
> +++ b/compat/bswap.h
> @@ -9,7 +9,7 @@
> * Default version that the compiler ought to optimize properly with
> * constant values.
> */
> -static inline unsigned int default_swab32(unsigned int val)
> +static inline uint32_t default_swab32(uint32_t val)
> {
> return (((val & 0xff000000) >> 24) |
> ((val & 0x00ff0000) >> 8) |
> @@ -20,7 +20,7 @@ static inline unsigned int default_swab32(unsigned int val)
> #if defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__))
>
> #define bswap32(x) ({ \
> - unsigned int __res; \
> + uint32_t __res; \
> if (__builtin_constant_p(x)) { \
> __res = default_swab32(x); \
> } else { \
> --
> 1.6.4
>
> Nicolas Pitre <nico@fluxnic.net>