connect to remote server using sockets unix - sockets

Question

In unix, I want to make a client program connect to a server running on different machine. For this, I need to enter the ip address of server through keyboard and then pass that ip address in the connect() system call of client. I tried reading as a string, and passing it.But it didnt work. Is there any specific way to pass the ip address?

Answer 1

Assuming IPv4, the function you're looking for is inet_addr, which converts the string representation of an IPv4 address to a numerical value which can be passed into various socket functions:
int get_connection(const char *ip, int port)
{
int sock;
struct sockaddr_in sin;
bzero(&sin,sizeof(sin));
sin.sin_family = AF_INET;
sin.sin_addr.s_addr = inet_addr(ip);
sin.sin_port = htons(port);
if ((sock=socket(AF_INET,SOCK_STREAM,0))==-1) {
perror("Error creating socket");
return -1;
}
if (connect(sock,(struct sockaddr *)&sin,sizeof(sin))==-1) {
perror("Couldn't connect");
close(sock);
return -1;
}
return sock;
}