int cvSliceLength( CvSlice slice, const CvSeq* seq );
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..ocv:cfunction:: int cvSliceLength( CvSlice slice, const CvSeq* seq )
Calculates the sequence slice length
Some of functions that operate on sequences take a ``CvSlice slice`` parameter that is often set to the whole sequence (CV_WHOLE_SEQ) by default. Either of the ``start_index`` and ``end_index`` may be negative or exceed the sequence length. If they are equal, the slice is considered empty (i.e., contains no elements). Because sequences are treated as circular structures, the slice may select a
few elements in the end of a sequence followed by a few elements at the beginning of the sequence. For example, ``cvSlice(-2, 3)`` in the case of a 10-element sequence will select a 5-element slice, containing the pre-last (8th), last (9th), the very first (0th), second (1th) and third (2nd)
elements. The functions normalize the slice argument in the following way: