netdb.h:
/* Description of data base entry for a single host. */
struct hostent
{
char *h_name; /* Official name of host. */
char **h_aliases; /* Alias list. */
int h_addrtype; /* Host address type. */
int h_length; /* Length of address. */
char **h_addr_list; /* List of addresses from name server. */
#define h_addr h_addr_list[0] /* Address, for backward compatibility. */
};
struct sockaddr{
unisgned short as_family;
char sa_data[14];
};
struct sockaddr_in{
unsigned short sin_family;
unsigned short int sin_port;
struct in_addr sin_addr;
unsigned char sin_zero[8];
}
typedef uint32_t in_addr_t;
struct in_addr
{
in_addr_t s_addr;
};