Question

I am writing a CLIENT/SERVER program and I have a problem with the client part.
In the client part, I start by receiving messages from the server but when I want to send a message to the server, I have a problem – how can I get the server socket that I can use as first parameter in the send function?

Function: int connect (int socket, struct sockaddr *addr, socklen_t length)

this is a part of the client code :

#if defined (WIN32)
#include <winsock2.h>
typedef int socklen_t;
#elif defined (linux)
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#define INVALID_SOCKET -1
#define SOCKET_ERROR -1
#define closesocket(s) close(s)
typedef int SOCKET;
typedef struct sockaddr_in SOCKADDR_IN;
typedef struct sockaddr SOCKADDR;
#endif

#include <stdio.h>
#include <stdlib.h>
#define PORT 23



int main(void)
{


#if defined (WIN32)
    WSADATA WSAData;
    int erreur = WSAStartup(MAKEWORD(2,2), &WSAData);
#else
    int erreur = 0;
#endif

SOCKET csock;
SOCKADDR_IN sin;
char buffer[32] = "";


if(!erreur)
{
    csock = socket(AF_INET, SOCK_STREAM, 0); 


    sin.sin_addr.s_addr = inet_addr("127.0.0.1");
    sin.sin_family = AF_INET;
    sin.sin_port = htons(PORT);

    if(connect(csock, (SOCKADDR*)&sin, sizeof(sin)) != SOCKET_ERROR)
    {


     // 
        if(recv(csock, buffer, 32, 0) != SOCKET_ERROR) 
            printf("Recu : %s\n", buffer);



         char buffer1[32] = "how are you  !";
         send( ?sock?, buffer1, 32, 0);  // here is my problem , so what is the first parameter(?sock?) in the "send" function that i need to send message to the server ?

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Answer 1

You already have it: it is your csock variable. TCP Connections are established both ways. When you connected to your sever you got value for your csock: you can use it for both sending and receiving data.