GRND_NONBLOCK
if (flags & ~(GRND_NONBLOCK | GRND_RANDOM | GRND_INSECURE))
if (flags & GRND_NONBLOCK)
if (unlikely(flags & ~(GRND_NONBLOCK | GRND_RANDOM | GRND_INSECURE)))
#ifndef GRND_NONBLOCK
ret = getrandom(&rng, sizeof(rng), GRND_NONBLOCK);
if (!getrandom(NULL, 0, GRND_NONBLOCK))