Programming Forums > Application Development > C++

Exodust · Jan 17th, 2007, 11:04 AM

Hi,
I am trying to make a chat program over a LAN network for my college project.
So as a start, I tried to make a server program and a client program, and ran them on the same pc using that loop back address 127.0.0.1.

Now, I successfully made the client program connect to the server program. But when I tried to implement send() and recv() to receive a string of text and show the text in a messagebox, I failed to do so. I can't find the error in the code. It is compiling with no problems, but while running, the server receives no text string.

Here is the code (for client) (showing only the windows procedure and the required functions:

(Toggle Plain Text)

HWND hwnd;
SOCKET s;

bool ConnectToHost(int PortNo,char* IPAddress)
{
     WSADATA wsadata;
     
     int error=WSAStartup(0x0202, &wsadata);
     
     if(error)
     return false;
     
     if(wsadata.wVersion!=0x0202)
     {
                                 WSACleanup();
                                 return false;
     }
     
     SOCKADDR_IN target;
     
     target.sin_family=AF_INET;
     target.sin_port=htons(PortNo);
     target.sin_addr.s_addr= inet_addr(IPAddress);
     
     s=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);
     
     if(s==INVALID_SOCKET)
     {return false;
     }
     
     if(connect(s,(SOCKADDR*)&target,sizeof(target))==SOCKET_ERROR)
     return false;
     else return true;
}

void CloseConnection()
{
     if(s)
     closesocket(s);
     WSACleanup();
}

LRESULT CALLBACK WindowProcedure (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    switch (message)                  /* handle the messages */
    {
        case WM_CREATE:
            { bool flag;
              flag=ConnectToHost(1337,"127.0.0.1");
              if(flag) MessageBox(hwnd,"Connected","Connected",MB_OK);
              else MessageBox(hwnd,"Error","Error",MB_OK);
              char messg[20]="Nice!!!!";
              send(s,messg,8,0);
            }
             break;
             
        case WM_QUIT:
             {CloseConnection();
             }
             break;
        case WM_DESTROY:
            PostQuitMessage (0);       /* send a WM_QUIT to the message queue */
            break;
        default:                      /* for messages that we don't deal with */
            return DefWindowProc (hwnd, message, wParam, lParam);
    }

    return 0;

Here is the code for the server program:

(Toggle Plain Text)

SOCKET s;
WSADATA w;
HWND hwnd;

bool ListenOnPort(int portno)
{
     int error=WSAStartup(0x0202,&w);
     
     if(error)
     {
              return false;
     }
     
     if(w.wVersion!=0x0202)
     {
              WSACleanup();
              return false;
     }
     
     SOCKADDR_IN addr;
     addr.sin_family=AF_INET;
     addr.sin_port=htons(portno);
     
     addr.sin_addr.s_addr=htonl(INADDR_ANY);
     
     s=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);
     
     if(s==INVALID_SOCKET)
     {
                           return false;
     }
     
     if(bind(s,(LPSOCKADDR)&addr,sizeof(addr))==SOCKET_ERROR)
     {
           return false;
     }
     
     listen(s,SOMAXCONN);
     WSAAsyncSelect(s,hwnd,MY_MESSAGE_NOTIFICATION,(FD_ACCEPT|FD_CONNECT|FD_READ|FD_CLOSE));
     
}

void CloseConnection()
{
     if(s)
     closesocket(s);
     WSACleanup();
}

LRESULT CALLBACK WindowProcedure (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    switch (message)                  /* handle the messages */
    {
        case WM_CREATE:
           ListenOnPort(1337);
           break;
           
        case WM_QUIT:
             CloseConnection();
             break;
        case MY_MESSAGE_NOTIFICATION:
             {
                  switch(lParam)
                  {
                      case FD_ACCEPT:
                           break;
                      case FD_CONNECT:
                           break;
                      case FD_READ:
                           char buffer[80];
                           memset(buffer,0,sizeof(buffer));
                           recv(s,buffer,sizeof(buffer)-1,0);
                           MessageBox(hwnd,buffer,"Captured Text...",MB_OK);
                           break;
                      case FD_CLOSE:
                           break;
                  }
              }
              break;
                                
        
        case WM_DESTROY:
            PostQuitMessage (0);       /* send a WM_QUIT to the message queue */
            break;
        default:                      /* for messages that we don't deal with */
            return DefWindowProc (hwnd, message, wParam, lParam);
    }

    return 0;
}

SOCKET s;
WSADATA w;
HWND hwnd;

bool ListenOnPort(int portno)
{
     int error=WSAStartup(0x0202,&w);
     
     if(error)
     {
              return false;
     }
     
     if(w.wVersion!=0x0202)
     {
              WSACleanup();
              return false;
     }
     
     SOCKADDR_IN addr;
     addr.sin_family=AF_INET;
     addr.sin_port=htons(portno);
     
     addr.sin_addr.s_addr=htonl(INADDR_ANY);
     
     s=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);
     
     if(s==INVALID_SOCKET)
     {
                           return false;
     }
     
     if(bind(s,(LPSOCKADDR)&addr,sizeof(addr))==SOCKET_ERROR)
     {
           return false;
     }
     
     listen(s,SOMAXCONN);
     WSAAsyncSelect(s,hwnd,MY_MESSAGE_NOTIFICATION,(FD_ACCEPT|FD_CONNECT|FD_READ|FD_CLOSE));
     
}

void CloseConnection()
{
     if(s)
     closesocket(s);
     WSACleanup();
}

LRESULT CALLBACK WindowProcedure (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    switch (message)                  /* handle the messages */
    {
        case WM_CREATE:
           ListenOnPort(1337);
           break;
           
        case WM_QUIT:
             CloseConnection();
             break;
        case MY_MESSAGE_NOTIFICATION:
             {
                  switch(lParam)
                  {
                      case FD_ACCEPT:
                           break;
                      case FD_CONNECT:
                           break;
                      case FD_READ:
                           char buffer[80];
                           memset(buffer,0,sizeof(buffer));
                           recv(s,buffer,sizeof(buffer)-1,0);
                           MessageBox(hwnd,buffer,"Captured Text...",MB_OK);
                           break;
                      case FD_CLOSE:
                           break;
                  }
              }
              break;
                                
        
        case WM_DESTROY:
            PostQuitMessage (0);       /* send a WM_QUIT to the message queue */
            break;
        default:                      /* for messages that we don't deal with */
            return DefWindowProc (hwnd, message, wParam, lParam);
    }

    return 0;
}

Exodust · Jan 19th, 2007, 12:44 AM

It's been two days, and no replies.....

I've searched through each instance of the function send() or recv() in the MSDN.... read some examples etc. All examples use the functions like I do. What's the problem then?

Forum veterans please read this and help. Dawei, where are you

Duck · Jan 20th, 2007, 8:29 AM

Quote:

if(connect(s,(SOCKADDR*)&target,sizeof(target))==SOCKET_ERROR)
return false;
else return true;

There could be other errors, but something that stands out to me is in your ConnectToHost function you haven't called the WSAAsyncSelect function to setup windows message-based notification of network events for the connect socket.

EDIT: By the way there are many nice example projects you can download from places like codeproject.com/gamedev.net

Exodust · Jan 20th, 2007, 10:46 AM

Ok, Thanks, I'll give it a shot. And thanks for the link.

Jan 17th, 2007, 11:04 AM	#1
Exodust Newbie Join Date: Mar 2006 Location: India, The great :p Posts: 7 Rep Power: 0	Problems with send() and recv() functions(socket programing) Hi, I am trying to make a chat program over a LAN network for my college project. So as a start, I tried to make a server program and a client program, and ran them on the same pc using that loop back address 127.0.0.1. Now, I successfully made the client program connect to the server program. But when I tried to implement send() and recv() to receive a string of text and show the text in a messagebox, I failed to do so. I can't find the error in the code. It is compiling with no problems, but while running, the server receives no text string. Here is the code (for client) (showing only the windows procedure and the required functions: (Toggle Plain Text) HWND hwnd; SOCKET s; bool ConnectToHost(int PortNo,char* IPAddress) { WSADATA wsadata; int error=WSAStartup(0x0202, &wsadata); if(error) return false; if(wsadata.wVersion!=0x0202) { WSACleanup(); return false; } SOCKADDR_IN target; target.sin_family=AF_INET; target.sin_port=htons(PortNo); target.sin_addr.s_addr= inet_addr(IPAddress); s=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP); if(s==INVALID_SOCKET) {return false; } if(connect(s,(SOCKADDR)&target,sizeof(target))==SOCKET_ERROR) return false; else return true; } void CloseConnection() { if(s) closesocket(s); WSACleanup(); } LRESULT CALLBACK WindowProcedure (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam) { switch (message) / handle the messages / { case WM_CREATE: { bool flag; flag=ConnectToHost(1337,"127.0.0.1"); if(flag) MessageBox(hwnd,"Connected","Connected",MB_OK); else MessageBox(hwnd,"Error","Error",MB_OK); char messg[20]="Nice!!!!"; send(s,messg,8,0); } break; case WM_QUIT: {CloseConnection(); } break; case WM_DESTROY: PostQuitMessage (0); / send a WM_QUIT to the message queue / break; default: / for messages that we don't deal with / return DefWindowProc (hwnd, message, wParam, lParam); } return 0; HWND hwnd; SOCKET s; bool ConnectToHost(int PortNo,char IPAddress) { WSADATA wsadata; int error=WSAStartup(0x0202, &wsadata); if(error) return false; if(wsadata.wVersion!=0x0202) { WSACleanup(); return false; } SOCKADDR_IN target; target.sin_family=AF_INET; target.sin_port=htons(PortNo); target.sin_addr.s_addr= inet_addr(IPAddress); s=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP); if(s==INVALID_SOCKET) {return false; } if(connect(s,(SOCKADDR)&target,sizeof(target))==SOCKET_ERROR) return false; else return true; } void CloseConnection() { if(s) closesocket(s); WSACleanup(); } LRESULT CALLBACK WindowProcedure (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam) { switch (message) / handle the messages / { case WM_CREATE: { bool flag; flag=ConnectToHost(1337,"127.0.0.1"); if(flag) MessageBox(hwnd,"Connected","Connected",MB_OK); else MessageBox(hwnd,"Error","Error",MB_OK); char messg[20]="Nice!!!!"; send(s,messg,8,0); } break; case WM_QUIT: {CloseConnection(); } break; case WM_DESTROY: PostQuitMessage (0); / send a WM_QUIT to the message queue / break; default: / for messages that we don't deal with / return DefWindowProc (hwnd, message, wParam, lParam); } return 0; Here is the code for the server program: (Toggle Plain Text) SOCKET s; WSADATA w; HWND hwnd; bool ListenOnPort(int portno) { int error=WSAStartup(0x0202,&w); if(error) { return false; } if(w.wVersion!=0x0202) { WSACleanup(); return false; } SOCKADDR_IN addr; addr.sin_family=AF_INET; addr.sin_port=htons(portno); addr.sin_addr.s_addr=htonl(INADDR_ANY); s=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP); if(s==INVALID_SOCKET) { return false; } if(bind(s,(LPSOCKADDR)&addr,sizeof(addr))==SOCKET_ERROR) { return false; } listen(s,SOMAXCONN); WSAAsyncSelect(s,hwnd,MY_MESSAGE_NOTIFICATION,(FD_ACCEPT\|FD_CONNECT\|FD_READ\|FD_CLOSE)); } void CloseConnection() { if(s) closesocket(s); WSACleanup(); } LRESULT CALLBACK WindowProcedure (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam) { switch (message) / handle the messages / { case WM_CREATE: ListenOnPort(1337); break; case WM_QUIT: CloseConnection(); break; case MY_MESSAGE_NOTIFICATION: { switch(lParam) { case FD_ACCEPT: break; case FD_CONNECT: break; case FD_READ: char buffer[80]; memset(buffer,0,sizeof(buffer)); recv(s,buffer,sizeof(buffer)-1,0); MessageBox(hwnd,buffer,"Captured Text...",MB_OK); break; case FD_CLOSE: break; } } break; case WM_DESTROY: PostQuitMessage (0); / send a WM_QUIT to the message queue / break; default: / for messages that we don't deal with / return DefWindowProc (hwnd, message, wParam, lParam); } return 0; } SOCKET s; WSADATA w; HWND hwnd; bool ListenOnPort(int portno) { int error=WSAStartup(0x0202,&w); if(error) { return false; } if(w.wVersion!=0x0202) { WSACleanup(); return false; } SOCKADDR_IN addr; addr.sin_family=AF_INET; addr.sin_port=htons(portno); addr.sin_addr.s_addr=htonl(INADDR_ANY); s=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP); if(s==INVALID_SOCKET) { return false; } if(bind(s,(LPSOCKADDR)&addr,sizeof(addr))==SOCKET_ERROR) { return false; } listen(s,SOMAXCONN); WSAAsyncSelect(s,hwnd,MY_MESSAGE_NOTIFICATION,(FD_ACCEPT\|FD_CONNECT\|FD_READ\|FD_CLOSE)); } void CloseConnection() { if(s) closesocket(s); WSACleanup(); } LRESULT CALLBACK WindowProcedure (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam) { switch (message) / handle the messages / { case WM_CREATE: ListenOnPort(1337); break; case WM_QUIT: CloseConnection(); break; case MY_MESSAGE_NOTIFICATION: { switch(lParam) { case FD_ACCEPT: break; case FD_CONNECT: break; case FD_READ: char buffer[80]; memset(buffer,0,sizeof(buffer)); recv(s,buffer,sizeof(buffer)-1,0); MessageBox(hwnd,buffer,"Captured Text...",MB_OK); break; case FD_CLOSE: break; } } break; case WM_DESTROY: PostQuitMessage (0); / send a WM_QUIT to the message queue / break; default: / for messages that we don't deal with */ return DefWindowProc (hwnd, message, wParam, lParam); } return 0; } __________________ My Blog!!

Jan 19th, 2007, 12:44 AM	#2
Exodust Newbie Join Date: Mar 2006 Location: India, The great :p Posts: 7 Rep Power: 0	It's been two days, and no replies..... I've searched through each instance of the function send() or recv() in the MSDN.... read some examples etc. All examples use the functions like I do. What's the problem then? Forum veterans please read this and help. Dawei, where are you __________________ My Blog!!

Jan 20th, 2007, 10:46 AM	#4
Exodust Newbie Join Date: Mar 2006 Location: India, The great :p Posts: 7 Rep Power: 0	Ok, Thanks, I'll give it a shot. And thanks for the link. __________________ My Blog!!

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Programming Forums > Application Development > C++

Problems with send() and recv() functions(socket programing)