when N is of a wider type and N > SIZE_MAX. */
#define xtimes(N, ELSIZE) \
((N) <= SIZE_MAX / (ELSIZE) ? (size_t) (N) * (ELSIZE) : SIZE_MAX)
when N is of a wider type and N > SIZE_MAX. */
#define xtimes(N, ELSIZE) \
((N) <= SIZE_MAX / (ELSIZE) ? (size_t) (N) * (ELSIZE) : SIZE_MAX)