Method SetAtGrow, etc.
For magnification of the size it is caused SetCount.
SetCount causes GrowBuffer.
GrowBuffer creates the new buffer, and for data migration from the old buffer in the new causes RelocateElements from class Traits specified by second argument CAtlArray.
Implementation RelocateElements on-default for the arbitrary types fulfills memmove, i.e. bit-by-bit copying.
(traits it is specified for some types - , the variant, guid and the built in integral types, but there is redefined only hash coding and comparing).
It turns out, CAtlArray "from a box" it is unsuitable for usage and demands ?