echo client problems

Hi,

I tried to post this problem in my other thread, but although I keep seeing the 'new posts' icon there are none, so I am going to try and repost this. Also I think since this is a different problem I should make a new thread, I'm sorry if I shouldn't do this but as far as I know I am following the rules.

I wrote a simple echo client in c++, but it keeps crashing whilst calling connect(). I have checked a few examples of other echo clients online, but cannot see what I am missing that theirs has. I am pretty lost so any hints or help would be very appreciated.

Quote:

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Could not connect to remote host.
connect: Socket operation on non-socket

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Here is the code for my client:

Code:

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#include<iostream>
#include<sys/socket.h>
#include<sys/types.h>
#include<netinet/in.h>
#include<arpa/inet.h>

#define DEST_IP "127.0.0.1"
#define MAX 1024

using namespace std;

int main()
{
        char buf[MAX];

        struct sockaddr_in dest_addr;

        int sock, len, check_recv, check_send;

        if ( sock=socket(PF_INET, SOCK_STREAM, 0 ) == -1 )
        {
                cout<<"Error, could not open socket\n";
        }

        dest_addr.sin_family = AF_INET;
        dest_addr.sin_port = htons(31337);
        dest_addr.sin_addr.s_addr = inet_addr(DEST_IP);
        memset( dest_addr.sin_zero, '\0', sizeof( dest_addr.sin_zero ) );

        if (( connect( sock, (struct sockaddr *)&dest_addr, sizeof(struct sockaddr_in))) == -1 )
        {
                cout<<"Could not connect to remote host.\n";
                perror("connect");
        }

        cin.getline( buf, MAX, '\n' );

        len = sizeof(buf);

        while(1)
        {

                check_send=send( sock, buf, len, 0 );
                switch ( check_send )
                {
                        case -1:
                                cout<<"Error sending, bailing out...\n";
                                break;
                        default:
                                cout<<check_send<<"Bytes sent\n";
                                break;
                }
                check_recv=recv( sock, buf, MAX, 0 );
                switch ( check_recv )
                {
                        case 0:
                                cout<<"Remote host closed connection.\n";
                                break;
                        case -1:
                                cout<<"Error receiving data.\n";
                                break;
                        default:
                                cout<<check_recv<<"Bytes received.\n";
                                break;
                }
        }
        close(sock);
}

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Calef13

refer to this table
http://www.cppreference.com/operator_precedence.html

Code:

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if ( sock=socket(PF_INET, SOCK_STREAM, 0 ) == -1 )

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the part in bold is evaluated first

Code:

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if ( ( sock=socket(PF_INET, SOCK_STREAM, 0 ) ) == INVALID_SOCKET )

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never assume -1 is the returned error value on failure;
The same goes for the switch statement.

Thanks for all the help guys, it connects now, just shows how much I still have to learn if I am still messing up operator precedence :P. Thanks about the heads up on the returning -1 but I didn't assume, beej's guide says it returns -1 on error. Is your method more generic so I can use that always instead of -1? If so then I will certainly be using that from now on :)

Once again, thanks for all the help guys.

Calef13

The method I showed (I wont claim its 'my' method) is more portable. AFAIK all sockets implementations do return -1 on failure, but they arent required to return a specific value. They are however required to define INVALID_SOCKET.