Read/write loop server/client

[Ozymandias0]

I have a read/write loop between a client and a server on a TCP socket, and I can't see why the loop is being gone through twice for every write from the client?

For every message that is entered by the client, the server loops through twice up until the second write.

Server:

again:
    while((bytes_read = read(newsockfd, data, 50))>0) {   // read from client
         if (bytes_read < 0 && errno == EINTR)
            goto again;
         else if (bytes_read < 0)
            cerr<<"read error"<<endl;
     data[bytes_read]='\0';         										
     cout<<data<<endl;			     // print message
     write(newsockfd, data, bytes_read);     // Write the buffer to the client
      }

Client:

while(cin.getline(sendbuf, 100)!=NULL) {    // get message from stdin
    cin.clear();
    if((nbytes = write(sfd, sendbuf,100))==-1) {   // write message to server
       cout<<"Write error"<<endl;
       exit(1);
    }					
    if((nbytes=read(sfd,recv, 100))==-1) {     // read message from server
       cout<<"Read error"<<endl;
       exit(1);
    }
    recv[nbytes]='\0';
    cout<<recv<<endl;                         // print message to stdout
   }

[coder777]

The point is that your client writes 100 bytes regardless what entered. Your server receives only 50 bytes. Hence it loops twice to get all the data.

[Ozymandias0]

Ah, how stupid of me! Thanks for pointing it out.