29 Numerics library [numerics]

29.6 Numeric arrays [numarray]

29.6.5 Class template slice_array [template.slice.array]

29.6.5.2 Assignment [slice.arr.assign]

void operator=(const valarray<T>&) const;
const slice_array& operator=(const slice_array&) const;

These assignment operators have reference semantics, assigning the values of the argument array elements to selected elements of the valarray<T> object to which the slice_array object refers.