BrokenPipe error occured in send data in socket programing

Question

I have a client side source code that connects to server over internet.
When I tracing my code it shows me the SIGPIPE error when the compiler run send code. where is my problem?
I changed send method as the comment say and used strcpy.
But I have error again.

#include <QCoreApplication>
#include <stdio.h>   /* Standard input/output definitions */
#include <string.h>  /* String function definitions */
#include <unistd.h>  /* UNIX standard function definitions */
#include <fcntl.h>   /* File control definitions */
#include <errno.h>   /* Error number definitions */
#include <termios.h> /* POSIX terminal control definitions */
#include <string>    /*To use string type*/
#include <iostream>
#include <string>
#include <QChar>
#include <stdlib.h>
#include <netdb.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <typeinfo>//for print the type typeid(a).name --> int
#include <string>
#include <arpa/inet.h>
#include <signal.h>
//#include <pthread.h> //make thread
using namespace std ;

//________________
#define bufsize 100
int sock;
struct sockaddr_in server;
string str;
char*     message = new char[bufsize];
char*     server_reply = new char[bufsize];
void RECV()
{
        memset(&server_reply,'\0',bufsize);
        int a=recv(sock , server_reply ,bufsize  , 0);
        cout<<a;
        if(server_reply[0]!='\0')
        cout<<server_reply<<endl;

}
int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);
    sock = socket(AF_INET , SOCK_STREAM , IPPROTO_TCP);//0
    if (sock == -1)
    {
        printf("Could not create socket");
    }
    puts("Socket created");
    server.sin_addr.s_addr = inet_addr("example.com");//
    server.sin_family = AF_UNSPEC;//AF_INET;
    server.sin_port = htons( 3490 );


    //Connect to remote server
    if (connect(sock , (struct sockaddr *)&server , sizeof(server)) < 0)
    {
        perror("connect failed. Error");
        return 1;
    }

    puts("Connected\n");
    puts("Bienvenido al Chatroom, puedes empezar a escribir en la sala!");

    strcpy(message,"Hi");
    signal(SIGPIPE, SIG_IGN);
    if((send(sock , message , strlen(message)+1 , 0))<0)
    {
        perror("send");
        exit(1);
    }
    RECV();   
    close(sock);
    return a.exec();
}

Answer 1

In both memset calls, you are passing the address of the pointer rather than the pointer itself. Because bufsize is 100, these memset calls will corrupt other memory. At that point, any number of bad things can happen.

Below is my version of your code that does not get the SIGPIPE. Most notable is that AF_UNSPEC has been changed to AF_INET.

#include <stdio.h>   /* Standard input/output definitions */
#include <string.h>  /* String function definitions */
#include <unistd.h>  /* UNIX standard function definitions */
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <signal.h>

#define bufsize 100

static int sock;
static char* message      = new char[bufsize];
static char* server_reply = new char[bufsize];

static void RECV(int sock)
{
  recv(sock, server_reply, bufsize, 0);

  printf("%s\n", server_reply);
}

int main(int argc, char *argv[])
{
  struct sockaddr_in server;

  message      = new char[bufsize];
  server_reply = new char[bufsize];

  sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);

  if (sock == -1)
  {
    printf("Could not create socket");
    return 1;
  }

  puts("Socket created");
  server.sin_addr.s_addr = inet_addr("93.184.216.34");
  server.sin_family = AF_INET;
  server.sin_port = htons( 80 );

  if (connect(sock, (struct sockaddr *)&server, sizeof(server)) < 0)
  {
    perror("connect failed. Error");
    return 1;
  }

  puts("Connected\n");
  puts("Bienvenido al Chatroom, puedes empezar a escribir en la sala!");

  strcpy(message,"GET http://example.com/index.html HTTP/1.1\r\n\r\n");
  signal(SIGPIPE, SIG_IGN);

  if ((send(sock, message, strlen(message)+1, 0))<0)
  {
    perror("send");
    return 1;
  }

  puts("Sent\n");
  RECV(sock);
  close(sock);
  return 0;
}