This sample application shows how to implement a Winsock TCP stream socket server. It checks an incoming message sent by the client and sends a message to the client. This sample can be run on different Windows CE–based devices or the same device with Client.exe.
#include <windows.h>
#include <winsock.h>
#define PORTNUM 5000 // Port number
#define MAX_PENDING_CONNECTS 4 // Maximum length of the queue
// of pending connections
int WINAPI WinMain (
HINSTANCE hInstance, // Handle to the current instance
HINSTANCE hPrevInstance,// Handle to the previous instance
LPTSTR lpCmdLine, // Pointer to the command line
int nCmdShow) // Show state of the window
{
int index = 0, // Integer index
iReturn; // Return value of recv function
char szServerA[100]; // ASCII string
TCHAR szServerW[100]; // Unicode string
TCHAR szError[100]; // Error message string
SOCKET WinSocket = INVALID_SOCKET, // Window socket
ClientSock = INVALID_SOCKET; // Socket for communicating
// between the server and client
SOCKADDR_IN local_sin, // Local socket address
accept_sin; // Receives the address of the
// connecting entity
int accept_sin_len; // Length of accept_sin
WSADATA WSAData; // Contains details of the Winsock
// implementation
// Initialize Winsock.
if (WSAStartup (MAKEWORD(1,1), &WSAData) != 0)
{
wsprintf (szError, TEXT("WSAStartup failed. Error: %d"),
WSAGetLastError ());
MessageBox (NULL, szError, TEXT("Error"), MB_OK);
return FALSE;
}
// Create a TCP/IP socket, WinSocket.
if ((WinSocket = socket (AF_INET, SOCK_STREAM, 0)) == INVALID_SOCKET)
{
wsprintf (szError, TEXT("Allocating socket failed. Error: %d"),
WSAGetLastError ());
MessageBox (NULL, szError, TEXT("Error"), MB_OK);
return FALSE;
}
// Fill out the local socket's address information.
local_sin.sin_family = AF_INET;
local_sin.sin_port = htons (PORTNUM);
local_sin.sin_addr.s_addr = htonl (INADDR_ANY);
// Associate the local address with WinSocket.
if (bind (WinSocket,
(struct sockaddr *) &local_sin,
sizeof (local_sin)) == SOCKET_ERROR)
{
wsprintf (szError, TEXT("Binding socket failed. Error: %d"),
WSAGetLastError ());
MessageBox (NULL, szError, TEXT("Error"), MB_OK);
closesocket (WinSocket);
return FALSE;
}
// Establish a socket to listen for incoming connections.
if (listen (WinSocket, MAX_PENDING_CONNECTS) == SOCKET_ERROR)
{
wsprintf (szError,
TEXT("Listening to the client failed. Error: %d"),
WSAGetLastError ());
MessageBox (NULL, szError, TEXT("Error"), MB_OK);
closesocket (WinSocket);
return FALSE;
}
accept_sin_len = sizeof (accept_sin);
// Accept an incoming connection attempt on WinSocket.
ClientSock = accept (WinSocket,
(struct sockaddr *) &accept_sin,
(int *) &accept_sin_len);
// Stop listening for connections from clients.
closesocket (WinSocket);
if (ClientSock == INVALID_SOCKET)
{
wsprintf (szError, TEXT("Accepting connection with client failed.")
TEXT(" Error: %d"), WSAGetLastError ());
MessageBox (NULL, szError, TEXT("Error"), MB_OK);
return FALSE;
}
for (;;)
{
// Receive data from the client.
iReturn = recv (ClientSock, szServerA, sizeof (szServerA), 0);
// Check if there is any data received. If there is, display it.
if (iReturn == SOCKET_ERROR)
{
wsprintf (szError, TEXT("No data is received, recv failed.")
TEXT(" Error: %d"), WSAGetLastError ());
MessageBox (NULL, szError, TEXT("Server"), MB_OK);
break;
}
else if (iReturn == 0)
{
MessageBox (NULL, TEXT("Finished receiving data"), TEXT("Server"),
MB_OK);
break;
}
else
{
// Convert the ASCII string to the Unicode string.
for (index = 0; index <= sizeof (szServerA); index++)
szServerW[index] = szServerA[index];
// Display the string received from the client.
MessageBox (NULL, szServerW, TEXT("Received From Client"), MB_OK);
}
}
// Send a string from the server to the client.
if (send (ClientSock, "To Client.", strlen ("To Client.") + 1, 0)
== SOCKET_ERROR)
{
wsprintf (szError,
TEXT("Sending data to the client failed. Error: %d"),
WSAGetLastError ());
MessageBox (NULL, szError, TEXT("Error"), MB_OK);
}
// Disable both sending and receiving on ClientSock.
shutdown (ClientSock, 0x02);
// Close ClientSock.
closesocket (ClientSock);
WSACleanup ();
return TRUE;
}