gethostbyaddr
struct hostent* gethostbyaddr(const void *address, socklen_t length, int type);
#define cap_gethostbyaddr(w, x, y, z) gethostbyaddr(x, y, z)
hp = gethostbyaddr((char *)&in, sizeof(in), AF_INET);
hp = gethostbyaddr((const char *)ip, sizeof(*ip), AF_INET);
__weak_alias(gethostbyaddr,_gethostbyaddr)