Socket Send error

Question

Hi,

I am using a unix socket. When buffer is send to the socket it gives me unknown error 196. Please help on this.

BOOL SendData(int iBuffer)
{
    //Send data over socket
    int nRet = send(m_listenSock, m_cBuffer, iBuffer, 0);

    if(SOCKET_ERROR > nRet)
    {
        //log the error char temp;
        int length= sizeof(int);
        int rc = getsockopt(m_listenSock,SOL_SOCKET,SO_ERROR,&temp,(socklen_t *)&length);

        //if(rc == 0)
        {
            errno = temp;
            perror("\nError is");
        }

#ifndef LINUX
        WSACleanup();
#else
        close(m_listenSock);
#endif

        printf("\nSend data failed to");

        return FALSE;
    }

    return TRUE;
}

Answer 1

If errno is set but the call didn't fail (i.e. it didn't return -1), then errno's value isn't related to the last call you did. You can try clearing first:

errno = 0;

To be on the safe side. What I'm trying to say is that you can't know that the value of errno is relevant except right after the call that set it. You must check all calls you do that can fail for success/failure.

Answer 2

To detect an error you SHOULD be checking that send returns -1. I don't know what SOCKET_ERROR is, but if it's -1, then the above code won't work right anyway.

Assuming you do get -1 from send(), then an error code will be in errno. It is not necessary to do a getsockopt to retrieve it.

There is no error code 196, so I'd be deeply suspicious about your error handling.

Also, if send() fails, you should probably not close the socket. You haven't specified either the address family or socket type, but I'm assuming AF_INET and SOCK_DGRAM respectively (i.e. UDP)