Problem with WIN32 Asynchronous Sockets

Hey, I`ve started learning win32 asynchronous sockets. but im having a problem when incomming connection arrive, accept succeed.
I`m using WSAAsyncSelect after listen function. when message arrives it invokes my WindowProcedure callback function and then it process the message, and the problem is when im trying to recv the message (by recvfrom, it always returns -1).
Here is my code:

#include <windows.h>
#define WM_WINSOCK 7083

LRESULT CALLBACK WindowProcedure (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam);
SOCKET sock;

int WINAPI WinMain (HINSTANCE hThisInstance, HINSTANCE hPrevInstance, LPSTR lpszArgument, int nFunsterStil)
{
	HWND hwnd;               /* This is the handle for our window */
	MSG messages;            /* Here messages to the application are saved */
	WNDCLASSEX wincl;        /* Data structure for the windowclass */

	/* The Window structure */
	wincl.hInstance = hThisInstance;
	wincl.lpszClassName = "winsock";
	wincl.lpfnWndProc = WindowProcedure;      /* This function is called by windows */
	wincl.style = CS_DBLCLKS;                 /* Catch double-clicks */
	wincl.cbSize = sizeof (WNDCLASSEX);

	/* Use default icon and mouse-pointer */
	wincl.hIcon = LoadIcon (NULL, IDI_APPLICATION);
	wincl.hIconSm = LoadIcon (NULL, IDI_APPLICATION);
	wincl.hCursor = LoadCursor (NULL, IDC_ARROW);
	wincl.lpszMenuName = NULL;                 /* No menu */
	wincl.cbClsExtra = 0;                      /* No extra bytes after the window class */
	wincl.cbWndExtra = 0;                      /* structure or the window instance */
	/* Use Windows's default color as the background of the window */
	wincl.hbrBackground = (HBRUSH) COLOR_BACKGROUND;

	/* Register the window class, and if it fails quit the program */
	if (!RegisterClassEx (&wincl))
		return 0;

	/* The class is registered, let's create the program*/
	hwnd = CreateWindowEx (
		0,                   /* Extended possibilites for variation */
		"winsock",         /* Classname */
		"bla",       /* Title Text */
		WS_OVERLAPPEDWINDOW, /* default window */
		CW_USEDEFAULT,       /* Windows decides the position */
		CW_USEDEFAULT,       /* where the window ends up on the screen */
		544,                 /* The programs width */
		375,                 /* and height in pixels */
		HWND_DESKTOP,        /* The window is a child-window to desktop */
		NULL,                /* No menu */
		hThisInstance,       /* Program Instance handler */
		NULL                 /* No Window Creation data */
		);

	/* Make the window visible on the screen */
	ShowWindow (hwnd, nFunsterStil);

	WSADATA w;
	int error = WSAStartup(0x0202, &w); // start up winsock
	/* Error checking */
	if(error)
		return 1;
	if(w.wVersion != 0x0202)
	{
		WSACleanup();
		return 1;
	}

	/* ip address and port to be bound */
	SOCKADDR_IN addr;
	addr.sin_family = AF_INET;
	addr.sin_port = htons(5912);
	addr.sin_addr.s_addr = htonl(INADDR_ANY);

	sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP); // create a tcp socket
	/* Error checking */
	if(sock == INVALID_SOCKET)
	{
		WSACleanup();
		return 1;
	}

	if(bind(sock, (SOCKADDR *)&addr, sizeof(addr)) == SOCKET_ERROR) // bind the ip address
	{
		WSACleanup();
		return 1;
	}


	listen(sock, SOMAXCONN); // listen on the port
	WSAAsyncSelect(sock, hwnd, WM_WINSOCK, (FD_ACCEPT | FD_READ | FD_CLOSE));
	/* Run the message loop. It will run until GetMessage() returns 0 */
	while (GetMessage (&messages, NULL, 0, 0))
	{
		/* Translate virtual-key messages into character messages */
		TranslateMessage(&messages);
		/* Send message to WindowProcedure */
		DispatchMessage(&messages);
	}

	/* The program return-value is 0 - The value that PostQuitMessage() gave */
	return messages.wParam;
}

LRESULT CALLBACK WindowProcedure (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
	switch (message)   /* handle the messages */
	{
	case WM_WINSOCK:
		switch (lParam) //If so, which one is it?
		{
		case FD_ACCEPT:
			{
				//Connection request was made
				SOCKADDR_IN _addr;
				int len = sizeof(_addr);
				if(accept(sock, (SOCKADDR *)&_addr, &len) != INVALID_SOCKET)
					MessageBox(hwnd, "Accept.", "Success", MB_OK);
			}
			break;
		case FD_READ:
			{
				//Incoming data; get ready to receive
				int len;
				sockaddr_in addr;
				char buffer[1024];
				int state = recvfrom(sock, buffer, 1023, 0, (SOCKADDR*)&addr, &len);
				if(state > 0)
				{
					buffer[state] = '\0';
					MessageBox(hwnd, buffer, "Success", MB_OK);
				}
			}
			break;
		case FD_CLOSE:
			//Lost the connection
			MessageBox(hwnd, "Closed.", "Success", MB_OK);
			break;
		}
		break;
	case WM_DESTROY:
		PostQuitMessage (0); /* send a WM_QUIT to the message queue */
		break;
	}

	return DefWindowProc (hwnd, message, wParam, lParam);
}

Thank you in advance :).

Edited by fondi, 16 July 2009 - 04:50 AM.