std::extents<IndexType,Extents...>::dynamic-index
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                    |   private: static constexpr auto /*dynamic-index*/( rank_type i ) noexcept;  | 
 (since C++23)  (exposition only*)  | 
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Returns the number of dynamic extents below index i. If i <= rank() is false, the behavior is undefined.
Parameters
| i | - | the index | 
Return value
The number of Er with r < i for which Er is a dynamic extent.
See also
| This section is incomplete |