C++:Client Server Communication: not all elements send and received with socket

Question

im playing with some client server examples on a linux system. One of this is form this site: http://tldp.org/LDP/LG/issue74/tougher.html

With this example I send a stringstream to the socket. The problem is, that i dont get all elements of the stringstream on both sides (Server of Cliend). Has someone an idee why not ?

// Definition of the Socket class

#ifndef Socket_class
#define Socket_class


#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <unistd.h>
#include <string>
#include <arpa/inet.h>


const int MAXHOSTNAME = 200;
const int MAXCONNECTIONS = 5;
const int MAXRECV = 500;

class Socket
{
 public:
  Socket();
  virtual ~Socket();

  // Server initialization
  bool create();
  bool bind ( const int port );
  bool listen() const;
  bool accept ( Socket& ) const;

  // Client initialization
  bool connect ( const std::string host, const int port );

  // Data Transimission
  bool send ( const std::string ) const;
  int recv ( std::string& ) const;


  void set_non_blocking ( const bool );

  bool is_valid() const { return m_sock != -1; }

 private:

  int m_sock;
  sockaddr_in m_addr;


};


#endif




// Implementation of the Socket class.


#include "Socket.h"
#include "string.h"
#include <string.h>
#include <errno.h>
#include <fcntl.h>



Socket::Socket() :
  m_sock ( -1 )
{

  memset ( &m_addr,
       0,
       sizeof ( m_addr ) );

}

Socket::~Socket()
{
  if ( is_valid() )
    ::close ( m_sock );
}

bool Socket::create()
{
  m_sock = socket ( AF_INET,
            SOCK_STREAM,
            0 );

  if ( ! is_valid() )
    return false;


  // TIME_WAIT - argh
  int on = 1;
  if ( setsockopt ( m_sock, SOL_SOCKET, SO_REUSEADDR, ( const char* ) &on, sizeof ( on ) ) == -1 )
    return false;


  return true;

}



bool Socket::bind ( const int port )
{

  if ( ! is_valid() )
    {
      return false;
    }



  m_addr.sin_family = AF_INET;
  m_addr.sin_addr.s_addr = INADDR_ANY;
  m_addr.sin_port = htons ( port );

  int bind_return = ::bind ( m_sock,
                 ( struct sockaddr * ) &m_addr,
                 sizeof ( m_addr ) );


  if ( bind_return == -1 )
    {
      return false;
    }

  return true;
}


bool Socket::listen() const
{
  if ( ! is_valid() )
    {
      return false;
    }

  int listen_return = ::listen ( m_sock, MAXCONNECTIONS );


  if ( listen_return == -1 )
    {
      return false;
    }

  return true;
}


bool Socket::accept ( Socket& new_socket ) const
{
  int addr_length = sizeof ( m_addr );
  new_socket.m_sock = ::accept ( m_sock, ( sockaddr * ) &m_addr, ( socklen_t * ) &addr_length );

  if ( new_socket.m_sock <= 0 )
    return false;
  else
    return true;
}


bool Socket::send ( const std::string s ) const
{
  int status = ::send ( m_sock, s.c_str(), s.size(), MSG_NOSIGNAL );
  if ( status == -1 )
    {
      return false;
    }
  else
    {
      return true;
    }
}


int Socket::recv ( std::string& s ) const
{
  char buf [ MAXRECV + 1 ];

  s = "";

  memset ( buf, 0, MAXRECV + 1 );

  int status = ::recv ( m_sock, buf, MAXRECV, 0 );

  if ( status == -1 )
    {
      std::cout << "status == -1   errno == " << errno << "  in Socket::recv\n";
      return 0;
    }
  else if ( status == 0 )
    {
      return 0;
    }
  else
    {
      s = buf;
      return status;
    }
}



bool Socket::connect ( const std::string host, const int port )
{
  if ( ! is_valid() ) return false;

  m_addr.sin_family = AF_INET;
  m_addr.sin_port = htons ( port );

  int status = inet_pton ( AF_INET, host.c_str(), &m_addr.sin_addr );

  if ( errno == EAFNOSUPPORT ) return false;

  status = ::connect ( m_sock, ( sockaddr * ) &m_addr, sizeof ( m_addr ) );

  if ( status == 0 )
    return true;
  else
    return false;
}

void Socket::set_non_blocking ( const bool b )
{

  int opts;

  opts = fcntl ( m_sock,
         F_GETFL );

  if ( opts < 0 )
    {
      return;
    }

  if ( b )
    opts = ( opts | O_NONBLOCK );
  else
    opts = ( opts & ~O_NONBLOCK );

  fcntl ( m_sock,
      F_SETFL,opts );

}




// Definition of the ServerSocket class

#ifndef ServerSocket_class
#define ServerSocket_class

#include "Socket.h"


class ServerSocket : private Socket
{
 public:

  ServerSocket ( int port );
  ServerSocket (){};
  virtual ~ServerSocket();

  const ServerSocket& operator << ( const std::string& ) const;
  const ServerSocket& operator >> ( std::string& ) const;

  void accept ( ServerSocket& );

};


// Implementation of the ServerSocket class

#include "ServerSocket.h"
#include "SocketException.h"


ServerSocket::ServerSocket ( int port )
{
  if ( ! Socket::create() )
    {
      throw SocketException ( "Could not create server socket." );
    }

  if ( ! Socket::bind ( port ) )
    {
      throw SocketException ( "Could not bind to port." );
    }

  if ( ! Socket::listen() )
    {
      throw SocketException ( "Could not listen to socket." );
    }

}

ServerSocket::~ServerSocket()
{
}


const ServerSocket& ServerSocket::operator << ( const std::string& s ) const
{
  if ( ! Socket::send ( s ) )
    {
      throw SocketException ( "Could not write to socket." );
    }

  return *this;

}


const ServerSocket& ServerSocket::operator >> ( std::string& s ) const
{
  if ( ! Socket::recv ( s ) )
    {
      throw SocketException ( "Could not read from socket." );
    }

  return *this;
}

void ServerSocket::accept ( ServerSocket& sock )
{
  if ( ! Socket::accept ( sock ) )
    {
      throw SocketException ( "Could not accept socket." );
    }
}



    #endif


// Definition of the ClientSocket class

#ifndef ClientSocket_class
#define ClientSocket_class

#include "Socket.h"


class ClientSocket : private Socket
{
 public:

  ClientSocket ( std::string host, int port );
  virtual ~ClientSocket(){};

  const ClientSocket& operator << ( const std::string& ) const;
  const ClientSocket& operator >> ( std::string& ) const;

};


#endif


// Implementation of the ClientSocket class

#include "ClientSocket.h"
#include "SocketException.h"


ClientSocket::ClientSocket ( std::string host, int port )
{
  if ( ! Socket::create() )
    {
      throw SocketException ( "Could not create client socket." );
    }

  if ( ! Socket::connect ( host, port ) )
    {
      throw SocketException ( "Could not bind to port." );
    }

}


const ClientSocket& ClientSocket::operator << ( const std::string& s ) const
{
  if ( ! Socket::send ( s ) )
    {
      throw SocketException ( "Could not write to socket." );
    }

  return *this;

}


const ClientSocket& ClientSocket::operator >> ( std::string& s ) const
{
  if ( ! Socket::recv ( s ) )
    {
      throw SocketException ( "Could not read from socket." );
    }

  return *this;
}


int main()
{
std::stringstream streamIn, streamOut;  // stream for server
    std::stringstream ssInput, ssOut;       // stream for client

    int size = 250;


    for(int i=0; i < size; i++)
    {
        ssInput << i << " ";
    }

    std::cout << "\nssInput.str()" << ssInput.str() << std::endl;

    // Create the socket
    ServerSocket server ( 30000 );

    ClientSocket client_socket ( "localhost", 30000 );

    ServerSocket new_sock;
    server.accept ( new_sock );

    client_socket << ssInput;

    new_sock >> streamIn;

    std::cout << "\nstreamIn.str()" << streamIn.str() << std::endl;


    for(int i=0; i < size; i++)
    {
        streamOut << i << " ";
    }

    std::cout << "\nstreamOut.str()" << streamOut.str() << std::endl;

    new_sock << streamOut;


    client_socket >> ssOut;


    std::cout << "\nssOut.str()" << ssOut.str() << std::endl;

}

This is the output:

---

ssInput.str()0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249

streamIn.str()0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65

streamOut.str()0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249

ssOut.str()0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65

---

Thx...

Answer 1

TCP streams are transmitted in packets. recv (and read) receive a part of the stream, i.e. the data from one or more packets.

You stop after the first successful recv, but you should instead call it again until there is no more data (or until certain bytes are received - this depends on your protocol* really).

The same applies to send. It returns the number of bytes sent, which can theoretically be less than the amount you wanted to send. You should check how many bytes were sent, and call send again as needed to send the remaining bytes.

---

* By protocol I mean there must be some kind of agreement on how the server and the client communicate.

For example, you could say "The data shall be transmitted in lines. A line is defined as a sequence of 0 or more characters followed by a '\n' character." In that case your server needs to call recv repeatedly and collect data until it encounters a '\n' character.

Or you could say "The data shall be transmitted in logical packets. A packet is defined as 2 bytes in network order, specifying the length of the message, followed by the message (not null-terminated)". Then you call recv, fetch the message length from the first 2 bytes, and call recv repeatedly if needed to gather that many bytes.

You also need to specify this separately for client->server (request), and server->client (response).

Finally, you specify who (client or server) and when closes the connection.

Answer 2

sorry it was the wrong codebase: this is the right one:

#include "ServerSocket.h"
#include "SocketException.h"

ServerSocket::ServerSocket(int port)
{
    if (!Socket::create())
    {
        throw SocketException("Could not create server socket.");
    }

    if (!Socket::bind(port))
    {
        throw SocketException("Could not bind to port.");
    }

    if (!Socket::listen())
    {
        throw SocketException("Could not listen to socket.");
    }

}

ServerSocket::~ServerSocket()
{
}

const ServerSocket& ServerSocket::operator <<(const std::string& s) const
{
    if (!Socket::send(s))
    {
        throw SocketException("Could not write to socket.");
    }

    return *this;

}

const ServerSocket& ServerSocket::operator >>(std::string& s) const
{
    if (!Socket::recv(s))
    {
        throw SocketException("Could not read from socket.");
    }

    return *this;
}

void ServerSocket::accept(ServerSocket& sock)
{
    if (!Socket::accept(sock))
    {
        throw SocketException("Could not accept socket.");
    }
}

const ServerSocket& ServerSocket::operator << ( const std::stringstream& ss ) const
{

    if ( ! Socket::write ( ss ) )
    {
      throw SocketException ( "Could not write stream to socket." );
    }

  return *this;

}


const ServerSocket& ServerSocket::operator >> ( std::stringstream& ss ) const
{

    if ( ! Socket::read ( ss ) )
    {
      throw SocketException ( "Could not read stream from socket." );
    }

  return *this;
}




#include "Socket.h"
//#include "string.h"
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#include <string>
#include <iostream>
#include <sstream>

Socket::Socket() :
        m_sock(-1)
{

    memset(&m_addr, 0, sizeof(m_addr));

}

Socket::~Socket()
{
    if (is_valid())
        ::close(m_sock);
}

bool Socket::create()
{
    m_sock = socket( AF_INET,
    SOCK_STREAM, 0);

    if (!is_valid())
        return false;

    // TIME_WAIT - argh
    int on = 1;
    if (setsockopt(m_sock, SOL_SOCKET, SO_REUSEADDR, (const char*) &on,
            sizeof(on)) == -1)
        return false;

    return true;

}

bool Socket::bind(const int port)
{

    if (!is_valid())
    {
        return false;
    }

    m_addr.sin_family = AF_INET;
    m_addr.sin_addr.s_addr = INADDR_ANY;
    m_addr.sin_port = htons(port);

    int bind_return = ::bind(m_sock, (struct sockaddr *) &m_addr,
            sizeof(m_addr));

    if (bind_return == -1)
    {
        return false;
    }

    return true;
}

bool Socket::listen() const
{
    if (!is_valid())
    {
        return false;
    }

    int listen_return = ::listen(m_sock, MAXCONNECTIONS);

    if (listen_return == -1)
    {
        return false;
    }

    return true;
}

bool Socket::accept(Socket& new_socket) const
{
    int addr_length = sizeof(m_addr);
    new_socket.m_sock = ::accept(m_sock, (sockaddr *) &m_addr,
            ( socklen_t *) &addr_length);

    if (new_socket.m_sock <= 0)
        return false;
    else
        return true;
}

void Socket::close()
{
    if (is_valid())
        ::close(m_sock);
}

bool Socket::send(const std::string s) const
{
    std::cout << "Socket :: send :: s.size()\t" << s.size() << std::endl;

    int status = ::send(m_sock, s.c_str(), s.size(), MSG_NOSIGNAL);
    if (status == -1)
    {
        std::cout << "Error :: Socket::send" << std::endl;
        return false;
    }
    else
    {
        return true;
    }
}

int Socket::recv(std::string& s) const
{
    char buf[MAXRECV + 1];

    s = "";

    std::memset(buf, 0, MAXRECV + 1);

    int status = ::recv(m_sock, buf, MAXRECV, 0);

    if (status == -1)
    {
        std::cout << "status == -1   errno == " << errno
                << "  in Socket::recv\n";
        return 0;
    }
    else if (status == 0)
    {
        return 0;
    }
    else
    {
        s = buf;
        return status;
    }
}

bool Socket::write(const std::stringstream& ss) const
{
    int status = ::write(m_sock, ss.str().c_str(), sizeof(ss));
    if (status == -1)
    {
        return false;
    }
    else
    {
        return true;
    }
}

int Socket::read(std::stringstream& ss) const
{
    char buf[MAXRECV + 1];
    std::string temp;

    std::memset(buf, 0, MAXRECV + 1);

    int status = ::read(m_sock, buf, MAXRECV);

    if (status == -1)
    {
        std::cout << "status == -1   errno == " << errno
                << "  in Socket::read stream\n";
        return 0;
    }
    else if (status == 0)
    {
        return 0;
    }
    else
    {
        temp.assign(buf);
        ss << temp;

        return status;
    }
}

bool Socket::connect(const std::string host, const int port)
{
    if (!is_valid())
        return false;

    m_addr.sin_family = AF_INET;
    m_addr.sin_port = htons(port);

    int status = inet_pton( AF_INET, host.c_str(), &m_addr.sin_addr);

    if ( errno == EAFNOSUPPORT)
        return false;

    status = ::connect(m_sock, (sockaddr *) &m_addr, sizeof(m_addr));

    if (status == 0)
        return true;
    else
        return false;
}

void Socket::set_non_blocking(const bool b)
{

    int opts;

    opts = fcntl(m_sock,
    F_GETFL);

    if (opts < 0)
    {
        return;
    }

    if (b)
        opts = (opts | O_NONBLOCK);
    else
        opts = (opts & ~O_NONBLOCK);

    fcntl(m_sock,
    F_SETFL, opts);

}

Answer 3

i have modify the write an read method. The write method seems to work. The read method doesnt.

bool Socket::write(const std::stringstream& ss) const
{
    int total_bytes_written = 0;

    while (total_bytes_written != 1024)
    {
                //  int status = ::write(m_sock, ss.str().c_str(), sizeof(ss));
        int bytes_written = ::write(m_sock, ss.str().c_str() + total_bytes_written, 500 - total_bytes_written);

        if (bytes_written == -1)
        {
            return false;
        }
        if(bytes_written == 0)
        {
            std::cout << "Socket :: write :: 2 :: DONE" << std::endl;
            return true;
        }
        std::cout << "Socket :: write :: 1 :: ss.str():\t" <<ss.str() << "\tsizeof(ss)\t"<< sizeof(ss) << "\tss.str().size()\t" << ss.str().size() <<std::endl;
        total_bytes_written += bytes_written;
    }
        return false;

}


int Socket::read(std::stringstream& ss) const
{
    int MAXRECV = 500;
    char buf[MAXRECV + 1];
    std::string temp;

    std::memset(buf, 0, MAXRECV + 1);

    int bytesRead = 0;
    int result;

    std::cout << "Socket :: read :: 1" << std::endl;
    while (bytesRead < MAXRECV)
    {
        std::cout << "Socket :: read :: 2" << std::endl;

        result = ::read(m_sock, buf , MAXRECV );
        if (result < 1)
        {
            std::cout << "status == -1   errno == " << errno
                    << "  in Socket::read stream\n";
            return 0;
        }
        if (result == 0)
        {
            std::cout << "Socket :: read :: 3 :: DONE" << std::endl;
            return 0;
        }


        bytesRead += result;
        temp.assign(buf);
        std::cout << "Socket :: read :: 4 :: bytesRead\t" << bytesRead <<"\ttemp::\t" << temp << std::endl;
        ss << temp;
    }

    return result;

}

This is the output:

ssInput.str()0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 E|N|D


Socket :: write :: 1 :: ss.str():   0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 E|N|D sizeof(ss)  188 ss.str().size() 895
Socket :: write :: 2 :: DONE
Socket :: read :: 1
Socket :: read :: 2
Socket :: read :: 4 :: bytesRead    500 temp::  0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 15

streamIn.str()0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 15

streamOut.str()0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 
Socket :: write :: 1 :: ss.str():   0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249   sizeof(ss)  188 ss.str().size() 890
Socket :: write :: 2 :: DONE
Socket :: read :: 1
Socket :: read :: 2
Socket :: read :: 4 :: bytesRead    500 temp::  0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 15

ssOut.str()0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 15

Answer 4

I think now its running: As a separator between every element i used a '|' char and to finish the transmission I check every element, if its contain a "E-N-D" string.

bool Socket::write(const std::stringstream& ss) const
{

    std::string stemp;
    std::stringstream tempSS;
    tempSS << ss.rdbuf();

    do
    {
        tempSS >> stemp;
        stemp+= "|";                        // seperator

        int bytes_written = ::write(m_sock, stemp.c_str() , stemp.length() );

        if (bytes_written == -1)
        {
            return false;
        }

    }while(stemp.find("E-N-D") ==  std::string::npos);

    return true;

}


int Socket::read(std::stringstream& ss) const
{
    std::string stemp;

    int result;

    do
    {
        char buf[MAXRECV + 1];
        std::memset(buf, 0, MAXRECV + 1);

        result = ::read(m_sock, buf , MAXRECV );
        if (result < 1)
        {
            std::cout << "status == -1   errno == " << errno
                    << "  in Socket::read stream\n";
            return 0;
        }
        stemp.assign(buf);
    }while(stemp.find("E-N-D") ==  std::string::npos);

    return result;

Thx for help