This is of use for defining comparator callbacks. Common approaches like return x-y are not safe due to the risks of overflow. Furthermore, the (x > y) - (x < y) trick is optimized to branchless code. This also documents this macro accordingly.
265f83f avutil/common: add FFDIFFSIGN macro
libavutil/common.h | 11 +++++++++++
1 file changed, 11 insertions(+)