On 2012-08-15 09:28:46 +0100, Måns Rullgård wrote: > aviad rozenhek <avia...@gmail.com> writes: > > > On Mon, Aug 13, 2012 at 12:33 PM, aviad rozenhek <avia...@gmail.com> wrote: > > > >> unary minus operator applied to unsigned type, result still unsigned > >> > >> > >> I get this compiler warning when using any if the specialized AVERROR_XXX > >> macros, like AVERROR_BSF_NOT_FOUND or AVERROR_DECODER_NOT_FOUND. > >> > >> the reason is because > >> > >>> #define AVERROR_BSF_NOT_FOUND (-MKTAG(0xF8,'B','S','F')) ///< > >>> Bitstream filter not found > >> > >> > >> and the result from MKTAG is *unsigned* . > > > > how about we stop using the high byte [which contains the sign, thus making > > the tag convertible to signed, like so, would this work? > > > > #define DEFINE_AVERROR_3CC_TAG(a, b, c) (-(int32_t)MKTAG(a, b, c, 0)) > > Or how about we revert 6b34fbb and fix the one case where that matters > differently?
Depends a little of that the user of MKTAG is expecting? Reverting 6b34fbb is only fine if we make clear that MKTAG is only supposed to be used with 7 bit chars. But I suspect most user of it will expect MKTAG(0xff, 0xff, 0xff, 0xff) to work. I would add a AVERROR_MKTAG without the unsigned cast and keep 6b34fbb. It has the additional advantage of removing use of the unprefixed MKTAG from a public header. avformat.h is the only other public header which uses MKTAG. Janne _______________________________________________ libav-devel mailing list libav-devel@libav.org https://lists.libav.org/mailman/listinfo/libav-devel
