#if __SIZEOF_SIZE_T__ == 8
: __first_{__v}
#elif __SIZEOF_SIZE_T__ == 4
: __first_{__v, __v >> __bits_per_word}
: __first_{static_cast<unsigned int>(__v),static_cast<unsigned int>(__v >> __bits_per_word)}
#else
#error This constructor has not been ported to this platform
#endif