Convert size_t (4 or 8) bytes to array of bytes same length.

bytes_to_array.cpp

#include <array>
#include <cstddef>

constexpr auto dissolve(size_t value) noexcept {
	return [=]<size_t... I>(std::index_sequence<I...>) noexcept -> std::array<uint8_t, sizeof(size_t)>{
		return { static_cast<uint8_t>((value >> (((sizeof(size_t)-1)*8) - (8 * I)) ) & 0xFF)... };
	}(std::make_index_sequence<sizeof(size_t)>());
}

auto convert2(size_t v) {
    return dissolve(v);
}