Re: [FFmpeg-devel] [PATCH]lavf/hevc: Fix type specifiers

[Andreas Rheinhardt <andreas.rheinhardt@outlook.com>]

Carl Eugen Hoyos:
> Fixes several warnings:
> warning: format specifies type 'unsigned char' but the argument has type 'unsigned int'
> ---
>  libavformat/hevc.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/libavformat/hevc.c b/libavformat/hevc.c
> index 1841dd5785..ca5187a92e 100644
> --- a/libavformat/hevc.c
> +++ b/libavformat/hevc.c
> @@ -848,15 +848,15 @@ static int hvcc_write(AVIOContext *pb, HEVCDecoderConfigurationRecord *hvcc)
>          if (array->numNalus == 0)
>              continue;
>  
> -        av_log(NULL, AV_LOG_TRACE, "array_completeness[%"PRIu8"]:               %"PRIu8"\n",
> +        av_log(NULL, AV_LOG_TRACE, "array_completeness[%u]:               %"PRIu8"\n",
>                 j, array->array_completeness);
> -        av_log(NULL, AV_LOG_TRACE, "NAL_unit_type[%"PRIu8"]:                    %"PRIu8"\n",
> +        av_log(NULL, AV_LOG_TRACE, "NAL_unit_type[%u]:                    %"PRIu8"\n",
>                 j, array->NAL_unit_type);
> -        av_log(NULL, AV_LOG_TRACE, "numNalus[%"PRIu8"]:                         %"PRIu16"\n",
> +        av_log(NULL, AV_LOG_TRACE, "numNalus[%u]:                         %"PRIu16"\n",
>                 j, array->numNalus);
>          for (unsigned k = 0; k < array->numNalus; k++)
>              av_log(NULL, AV_LOG_TRACE,
> -                    "nalUnitLength[%"PRIu8"][%"PRIu16"]:                 %"PRIu16"\n",
> +                    "nalUnitLength[%u][%u]:                 %"PRIu16"\n",
>                     j, k, array->nalUnitLength[k]);
>          j++;
>      }
> -- 

I didn't catch this, as I didn't get a warning at all. The reason for
this is that it is actually not problematic:
"The ellipsis notation in a function prototype declarator causes

argument type conversion to stop after the last declared parameter. The
default argument
 promotions are performed on trailing arguments." The default argument
promotions include promoting integral types of conversion rank < int to
int. So av_log() has to read an int/unsigned even when one uses a
%"PRIu8". And so my inttypes.h contains this:

# define PRIu8		"u"
# define PRIu16		"u"
# define PRIu32		"u"

No wonder neither GCC nor Clang warned about this.
Anyway, patch LGTM.

- Andreas
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