sockaddr_in에서 ip addr 얻기 ( IPv4 demo of inet_ntop() and inet_pton() )

// 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 it

inet_ntop(AF_INET, &(sa.sin_addr), str, INET_ADDRSTRLEN);

printf("%s\n", str); // prints "192.0.2.33"