Thread: Socket, client (help-me)

I am beginning in C, I made a server in delphi and one client in C with some examples that I found in net... I obtained to make the two if to communicate, however I am with some problems in client... one of them is the BUFFER_SIZE that I have that to define a fixed value... and has commands that they return texts bigger that the buffer, this to make a menu in client, I have that to pressure to enter to receive the remain from the messages.... what of it has made a mistake with my code and what can be improved?

thanks!!

Code:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <winsock.h>


#define BUFFER_SIZE 256
#define EXIT_CALL_STRING "FECHACON"

int remote_socket = 0;
int message_length = 0;

unsigned short remote_port = 0;

char remote_ip[32];
char message[BUFFER_SIZE];


struct sockaddr_in remote_address;

WSADATA wsa_data;


/* Exibe uma mensagem de erro e termina o programa */
void msg_err_exit(char *msg)
{
    fprintf(stderr, msg);
    system("PAUSE");
    exit(EXIT_FAILURE);
}


int main(int argc, char **argv)
{
    if (WSAStartup(MAKEWORD(2, 0), &wsa_data) != 0)
        msg_err_exit("WSAStartup() failed\n");

    printf("IP do servidor: ");
    scanf("%s", remote_ip);
    fflush(stdin);

    printf("Porta do servidor: ");
    scanf("%d", &remote_port);
    fflush(stdin);

    remote_socket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if (remote_socket == INVALID_SOCKET)
    {
        WSACleanup();
        msg_err_exit("socket() failed\n");
    }

    // preenchendo o remote_address (servidor)
    memset(&remote_address, 0, sizeof(remote_address));
    remote_address.sin_family = AF_INET;
    remote_address.sin_addr.s_addr = inet_addr(remote_ip);
    remote_address.sin_port = htons(remote_port);


    printf("conectando ao servidor %s...\n", remote_ip);
    if (connect(remote_socket, (struct sockaddr *) &remote_address, sizeof(remote_address)) == SOCKET_ERROR)
    {
        WSACleanup();
        msg_err_exit("connect() failed\n");
    }


    printf("digite as mensagens\n");
    do
    {
        // limpa o buffer
        memset(&message, 0, BUFFER_SIZE);

        printf("msg: ");
        gets(message);
        fflush(stdin);

        message_length = strlen(message);

        // envia a mensagem para o servidor
        if (send(remote_socket, message, message_length, 0) == SOCKET_ERROR)
        {
            WSACleanup();
            closesocket(remote_socket);
            msg_err_exit("send() failed\n");
        }
        
        //RECEBE MENSAGEM DO SERVIDOR
        // limpa o buffer
        memset(&message, 0, BUFFER_SIZE);
        // recebe a mensagem do cliente
        if (select(0,remote_socket,NULL,remote_socket,0)) {
          do{
            message_length = recv(remote_socket, message, BUFFER_SIZE, 0);
            if(message_length == SOCKET_ERROR)
             {
              WSACleanup();
              closesocket(remote_socket);
              msg_err_exit("recv() failed\n");
             }
           printf("%s\n tamanho da msg = %d", message, (int)message_length);
           }while(select(0,remote_socket,NULL,remote_socket,0) == 0);
          }
        
        
    }
    while(strcmp(message, EXIT_CALL_STRING)); // sai quando enviar um "#quit" para o servidor


    printf("encerrando\n");
    WSACleanup();
    closesocket(remote_socket);


    system("PAUSE");
    return 0;
}

Code:

memset(&message, 0, BUFFER_SIZE);

memset is expecting just the base pointer of your string, not pointer to pointer of your string. Just replace &message to message. Perhaps you will have to change that in quite a few places in your code.

And please avoid using gets, fflush, system (Have a look at our FAQ). There are reply dangerous function. Have you enables your warning flag yet. If not do that first

Code:

gcc -Wall -W <filename>

Which compiler are u using?

ssharish

I use the DEV-C++,

you obtained to understand my problem? it is everything functioning, I only have problems when receiving the message because of the size from the buffer!

I'm not sure I totally understand your problem. But is it possible to have your server send a prior message indicating the size of the buffer needed? This will allow you to dynamically allocate storage for the actual message that is causing the storage issue.