On Tue, Nov 17, 2015 at 04:54:10PM -0500, Ganesh Ajjanagadde wrote: > isnan and isinf are actually macros as per the standard. In particular, > the existing implementation has incorrect signature. Furthermore, this > results in undefined behavior for e.g double values outside float range > as per the standard. > > This patch corrects the undefined behavior for all usage within FFmpeg. > > Note that long double is not handled as it is not used in FFmpeg. > Furthermore, even if at some point long double gets used, it is likely > not needed to modify the macro in practice for usage in FFmpeg. See > below for analysis. > > Getting long double to work strictly per the spec is significantly harder > since a long double may be an IEEE 128 bit quad (very rare), 80 bit > extended precision value (on GCC/Clang), or simply double (on recent > Microsoft). > On the other hand, any potential future usage of long double is likely > for precision (when a platform offers extra precision) and not for range, > since > the range anyway varies and is not as portable as IEEE 754 single/double > precision. In such cases, the implicit cast to a double is well defined > and isinf and isnan should work as intended. > > Reviewed-by: Michael Niedermayer <mich...@niedermayer.cc> > Signed-off-by: Ganesh Ajjanagadde <gajjanaga...@gmail.com> > --- > libavutil/libm.h | 34 ++++++++++++++++++++++++++++++++-- > 1 file changed, 32 insertions(+), 2 deletions(-)
probably ok maybe wait a day or 2 before pushing so people can test it on more obscure platforms thx [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB I do not agree with what you have to say, but I'll defend to the death your right to say it. -- Voltaire
signature.asc
Description: Digital signature
_______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
