TCP sockets classes

I am trying to create a simple library for using TCP sockets. There are three classes, a main socket class, a class for a server and a class for a client. The main socket class is publicly inherited by the other classes. When a client calls scSend() the function works fine and the data is sent. However when a server calls either scSend() or scRecv() it fails and prints an error message. Why?

Here is the relavent code

Code:

---

class scSocket
{
  public:
      int scSend(char* data, int size);
      int scRecv(char* data, int size);

      int scRecvcallback();

      int scGetlasterror();

  protected:
      int sock;
      int error;
};


class scClient : public scSocket
{
  public:
      scClient();
      scClient(char* host, int port);

      ~scClient();


      int scConnect(char* host, int port);

  protected:
      bool scTryhostname(char* host, int port);
      bool scTryip(char* host, int port);
     
      struct sockaddr_in server;
      struct hostent *server2;
     
};


class scServer : public scSocket
{
  public:
      scServer();
      scServer(int port);
      ~scServer();

      int scListen(int port);

  protected:
      int listener;
      struct sockaddr_in aserver, aclient;
};


int scSocket::scSend(char* data, int size)
{
  int ret = write(sock, data, size);
  if(ret != size)
  {
      cout << "error sending data\nsend returned " << ret << endl;
      error = 4;
      return ret;
  }
  cout << "data sent" << endl;
  return 0;
}

int scSocket::scRecv(char* data, int size)
{
  int ret = read(sock, data, size);
  if(ret < 0)
  {
      cout << "error recving data\nrecv() returned " << ret << endl;
      error = 4;
  }
  cout << "data recved" << endl;
  return ret;
}

int scServer::scListen(int port)
{
  memset(&aserver, 0, sizeof(aserver));
  aserver.sin_family = AF_INET;
  aserver.sin_addr.s_addr = htonl(INADDR_ANY);
  aserver.sin_port = htons(port);

  if(bind(listener, (struct sockaddr *) &aserver, sizeof(aserver)) < 0)
  {
      cout << "error binding socket!\n";
      error = 1;
      return -1;
  }

  cout << "socket bound\n";
  listen(listener, 5);
  cout << "listening . . .\n";
  unsigned int clen = sizeof(aclient);

  if(sock = accept(listener, (struct sockaddr *) &aclient, &clen) < 0)
  {
      cout << "error accepting client!\n";
      error = 3;
      return -3;
  }

  cout << "connection accepted!\n";
  return 1;
}


scServer::scServer()
{
  listener = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
  if(listener < 0)
  {
      cout << "error creating listener socket" << endl;
      error = 1;
  }
  cout << "socket created\n";
}


int main()
{
  scServer ss(4651);

  char buf[50];
  bzero(buf, 50);

  ss.scRecv(buf, 50);

  cout << buf << endl;
}

---

I dont see any obvious place where scServer::scListen is called from.

Can you be more specific than "an error" ?

A lot of things set a variable called errno (which you can print with perror(), or get a meaningful description with strerror() )
Use that to tell you why things are not working.

Quote:

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Originally Posted by Salem

I dont see any obvious place where scServer::scListen is called from.

Can you be more specific than "an error" ?

A lot of things set a variable called errno (which you can print with perror(), or get a meaningful description with strerror() )
Use that to tell you why things are not working.

---

scServer::scListen is called in the overloaded constructor scServer(int port).

The error is scSocket::scRecv() always prints out the error message and returns -1.

Im googling for info about errno now. ;)

Code:

---

int scSocket::scRecv(char* data, int size)
{
        cout << "waiting to recv data\n";
        int ret = recv(sock, data, size, 0);
        if(ret < 0)
        {
                cout << "error recving data\nrecv() returned " << ret << endl;
                cout << h_errno << endl;
                error = 4;
        }
        cout << "data recved" << endl;
        return ret;
}

---

Output from this function

Code:

---

error recving data
recv() returned -1
0

---

This is obviously not correct. recv() returns -1 but h_errno says there was no error.

:confused:

> scServer::scListen is called in the overloaded constructor scServer(int port).
I'm assuming this is in some code you didn't post.

> cout << h_errno << endl;
Except I said errno.
h_errno is only used by the 'gethost' functions AFAIK.

I can't see anything terribly wrong to cause what you're describing. Some things to try:
In scRecv(), what is the value of sock? (Is it a valid socket?)
Is data actually sent from the other end? (Ethereal is a great program for that)