include 
    
     // All pointers to socket address structures are often cast to pointers// to this type before use in various functions and system calls:struct sockaddr {    unsigned short    sa_family;    // address family, AF_xxx    char              sa_data[14];  // 14 bytes of protocol address};// IPv4 AF_INET sockets:struct sockaddr_in {    short            sin_family;   // e.g. AF_INET, AF_INET6    unsigned short   sin_port;     // e.g. htons(3490)    struct in_addr   sin_addr;     // see struct in_addr, below    char             sin_zero[8];  // zero this if you want to};struct in_addr {    unsigned long s_addr;          // load with inet_pton()};// IPv6 AF_INET6 sockets:struct sockaddr_in6 {    u_int16_t       sin6_family;   // address family, AF_INET6    u_int16_t       sin6_port;     // port number, Network Byte Order    u_int32_t       sin6_flowinfo; // IPv6 flow information    struct in6_addr sin6_addr;     // IPv6 address    u_int32_t       sin6_scope_id; // Scope ID};struct in6_addr {    unsigned char   s6_addr[16];   // load with inet_pton()};// General socket address holding structure, big enough to hold either// struct sockaddr_in or struct sockaddr_in6 data:struct sockaddr_storage {    sa_family_t  ss_family;     // address family    // all this is padding, implementation specific, ignore it:    char      __ss_pad1[_SS_PAD1SIZE];    int64_t   __ss_align;    char      __ss_pad2[_SS_PAD2SIZE];};
    

// IPv4:struct sockaddr_in ip4addr;int s;ip4addr.sin_family = AF_INET;ip4addr.sin_port = htons(3490);inet_pton(AF_INET, "10.0.0.1", &ip4addr.sin_addr);s = socket(PF_INET, SOCK_STREAM, 0);bind(s, (struct sockaddr*)&ip4addr, sizeof ip4addr);// IPv6:struct sockaddr_in6 ip6addr;int s;ip6addr.sin6_family = AF_INET6;ip6addr.sin6_port = htons(4950);inet_pton(AF_INET6, "2001:db8:8714:3a90::12", &ip6addr.sin6_addr);s = socket(PF_INET6, SOCK_STREAM, 0);bind(s, (struct sockaddr*)&ip6addr, sizeof ip6addr);

// IPv4 demo of inet_ntop() and inet_pton()struct sockaddr_in sa;char str[INET_ADDRSTRLEN];// store this IP address in sa:inet_pton(AF_INET, "192.0.2.33", &(sa.sin_addr));// now get it back and print itinet_ntop(AF_INET, &(sa.sin_addr), str, INET_ADDRSTRLEN);printf("%s\n", str); // prints "192.0.2.33"// IPv6 demo of inet_ntop() and inet_pton()// (basically the same except with a bunch of 6s thrown around)struct sockaddr_in6 sa;char str[INET6_ADDRSTRLEN];// store this IP address in sa:inet_pton(AF_INET6, "2001:db8:8714:3a90::12", &(sa.sin6_addr));// now get it back and print itinet_ntop(AF_INET6, &(sa.sin6_addr), str, INET6_ADDRSTRLEN);printf("%s\n", str); // prints "2001:db8:8714:3a90::12"

struct sockaddr_in antelope;char *some_addr;inet_aton("10.0.0.1", &antelope.sin_addr); // store IP in antelopesome_addr = inet_ntoa(antelope.sin_addr); // return the IPprintf("%s\n", some_addr); // prints "10.0.0.1"// and this call is the same as the inet_aton() call, above:antelope.sin_addr.s_addr = inet_addr("10.0.0.1");