Socket Programming?

[kaidto]

Hello!

I'm trying to start programming sockets, but have no idea where to start from!! There is a lot of documentation, BUT! I'm kind of confused with it.

this is my server code

#include <cstdlib>
#include <iostream>
#include <netinet/in.h>

using namespace std;

/*
 * 
 */
int main(int argc, char** argv) {

    //We're creating the socket, AF_INET, SOCK_STREAM Type, 6 
    //stands for tcp.
    int fdc, fdl = socket(AF_INET, SOCK_STREAM, 6);
    
    //We're creating a struct from sockaddr_in 
    //AF_INET, custom port (15557), Ip is our loopback
    struct sockaddr_in dir = { AF_INET, htons(15557), INADDR_ANY};
    
    //Binding socket to port.
       char ch;
 
        bind(fdl, (sockaddr*) &dir, sizeof(dir));
        listen(fdl, 1);
        fdc = accept(fdl, NULL, NULL);        
        close(fdl);
        
        while (read(fdc, &ch, 1)) 
            write(1, &ch, 1);
        
        
        
        cout<<"\n";
        
        cout<<"End?";
        
    
    return 0;
}

What about read and write functions?

Why is the socket being closed trought close(fdl);?

AF_INET or AF_INET6?

Should I create this struct?

struct sockaddr_in dir = { AF_INET, htons(15557), INADDR_ANY};

this web page, shows totally different info from what I posted?

http://www.linuxhowtos.org/C_C++/socket.htm

Any Ideas from where to start?

Thanks in advance!

Regards!

[kbw]

What about read and write functions?

What about them?

Why is the socket being closed trought close(fdl);?

The server creates a socket to listen on. That is the one bound to port 15557 on all interfaces on your machine.

When a client connects, that connection is returned by accept() and you store it as fdc (file descriptor for client)
http://pubs.opengroup.org/onlinepubs/007908799/xns/accept.html

The server's listening socket is being closed because it does not want to accept any further connections.

Should I create this struct?

struct sockaddr_in dir = { AF_INET, htons(15557), INADDR_ANY};

Yes. You're binding that connection to a socket. That's how the sockets library identifies your server socket as a server socket that will service that end point.

An end point is a port on an address. But as you've specified INADDR_ANY, you're saying you want to bind to port 15557 on any network interface IP4 (AF_INET) that your computer has.

htos() means host to network short and deals with endian issues on your computer.
http://pubs.opengroup.org/onlinepubs/007908799/xns/htonl.html
http://en.wikipedia.org/wiki/Endianness

Any Ideas from where to start?

It's customary to point you here: http://www.beej.us/guide/bgnet/output/html/multipage/index.html

[kaidto]

Hmm, Thanks a lot!!!

that web page looks kind of interesting I will read it from start to end.

ok, and, if we want to prepare our server to receive multiple connections, what should we use? Threads?

we need a main while(true) loop or something like that?

[kaidto]

Incredible documentation.

Thanks. REALLY, THANKS!