INADDR_LOOPBACK
#define INADDR_LOOPBACK ((in_addr_t)0x7f000001)
# define INADDR_LOOPBACK 0x7f000001 /* loopback address */
#define INADDR_LOOPBACK ((unsigned long) 0x7f000001)
#define INADDR_LOOPBACK 0x7F000001U