[FFmpeg-devel] [PATCH V3 3/3] libavfilter: add filter dnn_detect for object detection

[Nicolas George]

Andreas Rheinhardt (12021-03-01):
> 3. As you probably guessed from the last part of 2., I don't think that
> casting avoids the possibility of undefined behaviour* (because this
> conversion is done automatically anyway); but it might very well protect
> the code from aggressively optimizing compilers.

Possibly not.

On the other hand, there is no doubt that (type *)((char *)structp +
offsetof(field)) would be valid, since:

- (char *)structp + offsetof(field) is really a pointer on field, so it
  has proper alignment for type;

- the entire array is within a memory block obtained through malloc().

So, worst case scenario, we can use this construct to work around a
compiler that does stupid optimizations.

Regards,

-- 
  Nicolas George
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