getentropy
error = getentropy(region, sizeof(struct uuid));
extern int getentropy(void *, size_t);
if (getentropy(rnd, sizeof (rnd)) == -1)
ret = getentropy(buf, sizeof (buf));
ret = getentropy(errbuf, sizeof (errbuf));
ret = getentropy(errbuf, 257);
ret = getentropy(errbuf, 256);
ret = getentropy(errbuf, 0);
ret = getentropy(NULL, sizeof (buf));
ret = getentropy(addr, sizeof (buf));